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  • Insulin
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  • Electronic Resource  (14,697)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Rechtsmedizin 9 (1999), S. 190-192 
    ISSN: 1434-5196
    Keywords: Key words Hypoglycaemia factitia ; Insulin ; Diet ; Lethal outcome ; Schlüsselwörter Hypoglykaemia factitia ; Insulin ; Diät ; Tödlicher Verlauf
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Wir berichten über den Fall einer 28jährigen, nicht insulinpflichtigen nicht-Diabetikerin, in deren Anamnese eine hypoglykaemische Episode vor dem Todeseintritt bekannt wurde. Autoptisch wurde eine (heimliche) Applikation von Insulin durch letal hohe Insulinspiegel im zentralen und peripheren Blut mit Hypoglykaemie diagnostiziert. Nach der Anamnese, den Ergebnissen des Ermittlungsverfahrens und der Autopsie konnte die Applikation von Insulin aus suizidaler und homizidaler Absicht oder im Rahmen eines Münchhausen-Syndroms ausgeschlossen werden. Vielmehr handelte es sich in der Gesamtschau um eine Hypoglykaemia factitia aus diätetischen Gründen.
    Notes: Abstract The medical history of a 28-year-old non-insulin-dependent and non-diabetic patient with a hypoglycaemic episode before death is reported. At autopsy, an (surreptious) insulin administration was documented by lethally high serum insulin in central and peripheral blood during hypoglycaemia, According to the anamnesis, the judical inquiry and the autopsy findings, a suicidal intent, murder by insulin or Munchhausen-syndrome could be excluded. We therefore diagnosed a hypoglycaemia factitia caused by the diet.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 77 (1999), S. 107-110 
    ISSN: 1432-1440
    Keywords: Key words Pancreatic islet transplantation ; Cryopreservation ; Conservation ; Insulin ; Nude mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cryopreservation is the only available technique for long-term storage of pancreatic islets. The freezing/thawing protocol may cause considerable loss of viable islet tissue and impair its function in vivo. The aim of this study was to investigate glucose and insulin levels after transplantation of fresh and cryo/thawed rat islets. Rat pancreatic islets were isolated following intraductal collagenase injection and Ficoll gradient purification. After isolation, islets were cultured for 24 h and then either transplanted or frozen after stepwise addition of DMSO according to Rajotte et al. and stored in liquid nitrogen. After rapid thawing islets were stepwise transferred into RPMI medium and cultured for another 24 h. The recipients were athymic mice with streptozotocine-induced diabetes. Two hundred fresh (n=13) or cryo/thawed (n=15) islets were transplanted beneath the renal capsule. Glucose levels were measured for 14 days and blood samples for insulin determination were obtained 15 min after i.p. glucagon (10 mg/kg) administration on day 14. Glucose levels were normalized (〈9 mmol/l) in all recipients within 3 days since transplantation. On day 14, mean fasting values±SE in fresh and cryo/thawed islet groups were 4.0±0.6 and 4.4±0.4 mmol/l, respectively (P〉0.05). Fasting insulin levels were higher in the cryo/thaw than in the fresh islet group (1.67±0.33 vs 0.57±0.13 ng/ml; P〈0.01). Post-glucagon levels did not differ significantly (1.45±0.24 vs 0.86±0.24 ng/ml; P=0.06). While glucagon significantly increased insulin levels (P〈0.01) in the fresh islet group, no change in insulin levels was observed (P〉0.05) in the cryo/thaw group. Immunohistochemical staining demonstrated fragmentation of viable islet tissue which was more apparent in the cryo/thaw group. We conclude that in a short-term study cryo/thawed rat islets produce higher insulin levels than fresh islets transplanted into nude mice. This may be due to better islet survival or loss of feed-back regulation.
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  • 3
    ISSN: 1432-2307
    Keywords: Key words Rat ; Pancreatic beta cell ; Insulin ; GLUT2 glucose transporter ; Glucokinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Functional heterogeneity among pancreatic beta cells is a characteristic feature of the islets of Langerhans. Under physiological conditions, beta cells in the pancreas of fed rats exhibited heterogeneous immunohistochemical staining for insulin and glucokinase. Intracellular beta cell glucokinase staining was either faint or dense. In the pericapillary space beta cell glucokinase immunoreactivity had a polar orientation, with the highest density in cytoplasmic regions close to the blood vessels. Starvation resulted in a loss of heterogeneity with homogeneous insulin staining in all beta cells of the islets, and this was accompanied by a loss of heterogeneous glucokinase staining. The intracellular polarity of glucokinase staining in contact to blood vessels also disappeared after starvation. Refeeding resulted in the reappearance of intercellular heterogeneity. In dependence on the functional demand, the endocrine pancreas recruited insulin from beta cells according to a well-defined hierarchy, with an initial preferential mobilization of medullary beta cells. In the course of this process intracellular polarity of glucokinase staining reappeared in areas of the beta cell with functional contact to the GLUT2 glucose transporter in the plasma membrane. This can be regarded as the morphological correlate of an activation of the glucose signal recognition apparatus. Interestingly, the study also provides evidence that the changes in glucokinase distribution apparently preceded those in insulin distribution, which is in keeping with the central role of glucokinase as the glucose sensor of the pancreatic beta cell.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 209 (1999), S. 447-450 
    ISSN: 1432-041X
    Keywords: Key words Bombyxin ; Insulin ; Bombyx mori ; Electroporation ; Cell-specific expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A transgene reporter consisting of the bombyxin gene promoter and the green fluorescent protein coding region was introduced into intact brains of the silkworm Bombyx mori by in vitro electroporation. After in vitro culture of the brains, the fluorescence derived from the introduced reporter gene was observed in all cases in eight neurosecretory cells that had previously been identified as bombyxin-producing cells (BPCs). Although the fluorescence was not always observed in all cells, it was specific to BPCs, indicating that the reporter was under the control of the bombyxin gene promoter in a BPC-specific manner. Electroporatical introduction of a reporter gene was therefore found to be a suitable method for analyzing cell-specific expression in intact tissues and to be substitute for germ-line transmission of reporters in the transgenic system. Application of this technique enables us to analyze the cell-specific expression of transgene reporters within a few days and treat more than several dozens of the reporters within 1 month, which is difficult to do with the transgenic system.
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  • 5
    ISSN: 1432-1912
    Keywords: Key words Arterial smooth muscle ; Glucose ; Inducible NO synthesis ; Insulin ; Lean and obese Zucker rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Insulin has been suggested to prevent the induction of nitric oxide synthase (NOS) in vitro in arterial smooth muscle, but whether such a mechanism is operative in vivo is not known. Therefore, we evaluated the sensitivity of smooth muscle NOS to induction by interleukin-1β (IL-1β) in aortic rings of lean and obese Zucker rats, a model of experimental hyperinsulinaemia. In order to modulate the insulin and glucose balance of the rats, a 22-week-long treadmill exercise was included in the study. The training attenuated weight gain and reduced blood glucose in the obese and lean rats, whereas the abnormally high plasma insulin of the obese rats remained unaffected. A 6-h incubation of aortic rings with IL-1β (10 ng/ml) increased cyclic GMP in smooth muscle by approximately threefold in all groups, and this effect was prevented by methylene blue. The contractile sensitivity of endothelium-denuded aortic rings to phenylephrine was reduced by incubation with IL-1β (1 ng/ml and 10 ng/ml) in the exercised obese and lean rats, whereas no significant change was observed in the sedentary groups. The aortic maximal contractile force induced by phenylephrine was reduced in sedentary and exercised obese rats by incubation with IL-1β, while no change was detected in the lean rats. The aortic relaxation to exogenous L-arginine was augmented by IL-1β in all groups, while the relaxation sensitivity to L-arginine after induction by IL-1β was enhanced by exercise in the obese but not in the lean rats. Finally, the relaxation to nitroprusside was not significantly affected by IL-1β in any of the study groups. In conclusion, since maximal contractile force generation to phenylephrine was reduced by IL-1β in the obese but not in the lean rats, the sensitivity of NOS to induction by IL-1β was higher in arterial smooth muscle of the obese than the lean Zucker rats. Thus, this model of hyperinsulinaemia was not associated with reduced sensitivity of smooth muscle NOS to induction by IL-1β. Regular exercise did not change plasma insulin concentrations, but it enhanced the action of insulin in both strains as reflected by reduced blood glucose, and increased the sensitivity of smooth muscle NOS to induction by IL-1β.
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  • 6
    ISSN: 1432-2013
    Keywords: Key words A6 cells ; Capacitance ; Hormones ; Insulin ; Membrane area ; Membrane traffic ; Renal epithelia ; Water permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The role of membrane traffic in the stimulation of apical Na+ permeability caused by increases in cytoplasmic cyclic AMP was assessed by measuring the effects of forskolin on transepithelial capacitance (C T), transepithelial conductance (G T), and short-circuit current (I sc) in A6 cultured toad kidney cells. Apical water permeability was probed by recording cell volume changes after reducing the osmolality of the apical bath. We found that forskolin does not increase the osmotic water permeability of the apical membrane of A6 cells, and thus does not stimulate the insertion of water channels. Comparison of the effects of forskolin and insulin on Na+ transport demonstrated that both agents produce reversible increases in C T, G T and I sc. G T and C T increased proportionally during the rising phase of the insulin response. However, a non-linear relationship between both parameters was recorded when forskolin was given in NaCl Ringer’s solution. The relationship between C T and G T became linear after the effects of forskolin on Cl– conductances were eliminated by substituting Cl– by an impermeant anion. In contrast, in Cl–-containing Na+-free solutions, the non-linearity became more pronounced. Successive additions of insulin and forskolin caused additive increases in C T. Because increases in C T and Na+ transport occurred in the absence of stimulation of water permeability and increases of C T and G T were directly proportional when Na+ was the major permeating ion across the apical membrane, we suggest that the increase in apical Na+ permeability in the presence of either forskolin or insulin is due to the insertion of channels residing in intracellular pools. In contrast, the increased Cl– permeability caused by forskolin may be related to the activation of channels already present in the membrane.
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  • 7
    ISSN: 1432-2013
    Keywords: Key words Hypokalaemic periodic paralysis ; ATP-sensitive K+ channels ; Insulin ; Skeletal muscle ; Patch clamp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In the present work, we examined the effects of in vivo administration of insulin to rats made hypokalaemic by feeding a K+-free diet. The i.p. injection of insulin in the hypokalaemic rats provoked muscle paralysis within 3–5 h. Consistent with this observation, the skeletal muscle fibres of the paralysed rats were depolarized. In contrast, in the normokalaemic animals, insulin neither provoked paralysis nor produced significant fibre hyperpolarization. In the hypokalaemic rats, insulin almost completely abolished the sarcolemma adenosine triphosphate (ATP)-sensitive K+ currents without altering the sensitivity of the channels to ATP or glibenclamide. In contrast, in the normokalaemic rats, insulin enhanced ATP-sensitive K+ currents that became also resistant to ATP and glibenclamide. Our experiments indicate that the modulation of the sarcolemma ATP-sensitive K+ channels by insulin is impaired in the hypokalaemic state. This phenomenon appears to be related to the fibre depolarization and paralysis observed in the same animals.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta diabetologica 36 (1999), S. 93-97 
    ISSN: 1432-5233
    Keywords: Key words Type 2 diabetes mellitus ; Insulin ; Acarbose ; Gliclazide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In this prospective study we aimed to compare insulin plus acarbose with insulin plus gliclazide with respect to their effect on insulin requirement, lipid profiles and body mass index (BMI) while achieving good glycemic control. Forty patients with type 2 diabetes mellitus who were on conventional insulin therapy (subcutaneous insulin therapy consisting of regular and NPH insulin, two times a day) were included in the study. They were randomized to double blind treatment with insulin in combination with gliclazide or acarbose for 6 months. For both groups, acceptable glycemic control was achieved at the end of study period. The mean HbA1c levels decreased from 8.32±0.26 to 7.13±0.18% in acarbose group and 8.6±0.15 to 7.48±0.21% in the gliclazide group. The difference between groups was not significant (P 0.29). In the acarbose group, total cholesterol and LDL concentration decreased significantly while other parameters did not change. In the gliclazide group, HDL levels decreased significantly from 46.6±2.48 mg/dl to 41.3±2.09 mg/dl (P 0.001) BMI increased significantly from 27.60±1.21 kg/m2 to 28.69±1.26 kg/m2. (P 0.003) Total daily insulin dose was not changed in the acarbose group significantly, but increased from 42.6±2.73 to 49.27±3.58 U/day, which was significant in gliclazide group of (P 0.016). In the acarbose group, there were no significant differences between responders and nonresponders with respect to fasting and stimulated C-peptide, HbA1c levels and baseline BMI values. But in the gliclazide group, baseline BMI values were significantly higher in the nonresponding group compared to responders (P 0.02). In conclusion, combination of insulin with acarbose can be a good alternative for type 2 diabetic patients on insulin therapy; seems more beneficial than combination with gliclazide; may have advantage of achieving good glycemic control without increasing insulin dose and BMI; also may have the advantage of providing a decrease in LDL level, which are all important to prevent atherosclerosis.
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  • 9
    ISSN: 1432-2277
    Keywords: Key words Cyclosporin A ; Langerhans ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the effect of different doses of cyclosporin A (CyA) on glucose and insulin levels, as well as its residual effects on pancreatic islets ultrastructure after discontinuation of the drug. We studied four groups of Wistar rats. One control- (n = 5) and three experimental groups, n = 10 each, were treated with different doses of CyA IM for 14 days: group I, 5 mg/Kg; group II, 15 mg/Kg; and group III, 25 mg/Kg. Five animals of each group were sacrificed after 14 days, and the remaining five after 21 days to assess residual CyA effects. On the day of sacrifice, the rats underwent maltose absorption test, and glucose and insulin levels were measured. Pancreatic biopsies were obtained on day 21 to evaluate islets ultrastructure by electron microscopy. As a result, statistically significant, dose dependent (P 〈 0.05) increases in glucose and insulin levels were observed in CyA-treated groups. Groups II and III showed insulin levels significantly higher after fasting (P 〈 0.05) on day 14 comparing to the controls, while in groups I and II values returned to normal after CyA discontinuation. Group III showed persistently increased insulin levels on day 21. Pancreatic ultrastructural changes were observed only in group III. We can conclude that CyA effects on glucose and insulin levels were temporary and reversible at low doses. Ultrastuctural changes in the pancreatic islets may occur with high doses of CyA.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 79 (1999), S. 331-335 
    ISSN: 1439-6327
    Keywords: Key words Leptin ; Exercise Energy balance ; Insulin ; Glucocorticoids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In subjects who maintain a constant body mass, the increased energy expenditure induced by exercise must be compensated by a similar increase in energy intake. Since leptin has been shown to decrease food intake in animals, it can be expected that physical exercise would increase energy intake by lowering plasma leptin concentrations. This effect may be secondary either to exercise-induced negative energy balance or to other effects of exercise. To delineate the effects of moderate physical activity on plasma leptin concentrations, 11 healthy lean subjects (4 men, 7 women) were studied on three occasions over 3 days; in study 1 they consumed an isoenergetic diet (1.3 times resting energy expenditure) over 3 days with no physical activity; in study 2 the subjects received the same diet as in study 1, but they exercised twice daily during the 3 days (cycling at 60 W for 30 min); in study 3 the subjects exercised twice daily during the 3 days, and their energy intake was increased by 18% to cover the extra energy expenditure induced by the physical activity. Fasting plasma leptin concentration (measured on the morning of day 4) was unaltered by exercise [8.64 (SEM 2.22) 7.17 (SEM 1.66), 7.33 (SEM 1.72) 1μg · l−1 in studies 1, 2 and 3, respectively]. It was concluded that a moderate physical activity performed over a 3-day period does not alter plasma leptin concentrations, even when energy balance is slightly negative. This argues against a direct effect of physical exercise on plasma leptin concentrations, when body composition is unaltered.
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  • 11
    ISSN: 1435-232X
    Keywords: Key words Complex disease ; Carbohydrate ; Insulin ; Aboriginal populations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We undertook a genome-wide scan using 190 markers with an average separation of 20 cM in 49 Canadian Oji-Cree sib pairs affected with type 2 diabetes. Four of these markers, one each on chromosomes 6, 8, 16, and 22, showed both suggestive linkage and suggestive association with type 2 diabetes in the Oji-Cree. None of these markers corresponded to any chromosomal region or marker that has so far been linked with type 2 diabetes in other populations. Thus, there might be several genetic loci that confer susceptibility to type 2 diabetes in this study sample. We are following up on these preliminary leads by increasing the density of the markers within these linked and associated regions, and also by increasing the number of study subjects. Also, we found instances in which there were wide disparities between the Oji-Cree and reference Caucasians with respect to marker heterozygosity. This suggests that a particular set of markers for genome-wide scanning will have different informativeness in different ethnic groups. Thus, different marker sets will likely be required for different ethnic groups in order to maximize their information content for linkage calculations.
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  • 12
    ISSN: 1432-1440
    Keywords: Key words Postprandial hyperlipoproteinemia ; Lipoprotein lipase ; Insulin ; Apolipoprotein E ; Hyperlipoproteinemia type III
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Type III hyperlipoproteinemia (HLP) is a multifactorial disorder associated with homozygosity for the apolipoprotein (apo) E-2 allele. Factors which may promote the development of HLP include lipoprotein lipase (LPL) and hyperinsulinemia. These factors were investigated in eight patients with type III HLP and in nine normolipidemic controls. In vitro the interaction of apoE with LPL was analyzed in cell binding assays. All type III HLP patients showed delayed triglyceride (TG) clearance and remnant lipoprotein accumulation in an oral fat tolerance test. Normolipidemic apoE-2/2 controls revealed normal TG clearance comparable to apoE3/3 controls. HLP patients showed lower LPL activity and mass than controls. Analysis of the LPL gene revealed an Asn 291→Ser mutation in three patients and a –93 T-G substitution combined with an Asp 9→Asn mutation in one control subject. In addition to LPL abnormalities, postprandial hyperinsulinemia was observed in five out of eight patients. In vitro LPL compensated the defective function of apoE-2 in mediating remnant lipoprotein binding to cells. In summary, seven out of eight patients with type III HLP showed LPL abnormalities and/or postprandial hyperinsulinemia. Together with the in vitro data these findings support a coordinate effect of apoE and LPL for the manifestation of type III HLP. Hyperinsulinemia appears to be an additional factor important for disease expression.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 433 (1998), S. 495-504 
    ISSN: 1432-2307
    Keywords: Key words Insulinomas ; Prohormone convertases ; Carboxypeptidase H ; Insulin ; Proinsulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Sixty-seven insulinomas were investigated by immunohistochemistry using site-directed antibodies against insulin, proinsulin, chromogranin A, HISL-19, and four proteins directly or indirectly involved in the proteolytic processing of proinsulin: the prohormone convertases PC2 and PC3, carboxypeptidase H (CPH) and 7B2. Results were expressed in a six-grade score according to the frequency of immunoreactive tumour cells. Insulin was expressed by all tumours, appearing in either a diffuse or a polarized pattern and being detected in more than 30% of tumour cells in all cases but three. Proinsulin was also expressed in all tumours, with more than 50% of tumour cells immunoreactive in all cases but 5. It was consistently localized in the Golgi apparatus. In about half the cases, moreover, it also showed diffuse cytoplasmic staining, usually with a very sparse distribution. Trabecular and solid insulinomas did not present specific, homogeneous patterns of insulin immunostaining. However, insulin immunoreactivity was much more abundant in trabecular than in solid neoplasms, being present in virtually all tumour cells (score 6) in 50% and 8% of cases, respectively. Virtually all insulinomas expressed PC2, PC3, CPH and 7B2, usually in 30–100% of tumour cells, with a frequency significantly related to that of insulin. However, detection of PC2 and 7B2 was slightly less frequent than that of PC3 and CPH. In consecutive sections these proteins were found to be mostly co-localized with insulin and chromogranin A but not with proinsulin. They were heavily expressed in all 10 tumours with more than 10% of cells showing cytoplasmic proinsulin immunoreactivity, indicating that the leakage of proinsulin from the Golgi compartment is not associated with faulty expression of converting enzymes and possibly reflects a saturated processing capacity. HISL-19 immunoreactivity was found in both Golgi apparatus and insulin stores, indicating that the relevant antigen is different from all other proteins investigated. These results do not support a defect in expression or localization of proinsulin-processing enzymes in most insulinomas.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 96 (1998), S. 144-150 
    ISSN: 1432-0533
    Keywords: Key words Neuropathy ; Hypoglycaemia ; Hyperglycaemia ; Insulin ; BB/Wor rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To elucidate the pathophysiology of diabetic neuropathy many workers have examined nerve specimens from diabetic rats. While most workers found that animals with high blood glucose levels develop neuropathy, some researchers report that the peripheral nerves are normal in hyperglycaemic rats. Hypoglycaemia may also cause neuropathy. Some workers suggest that neuropathy is linked to fluctuations of the blood glucose level. In the present study we examine plantar nerves of diabetic BB/ Wor rats maintained on an eu-/hyperglycaemic or an eu-/ hypoglycaemic regime with insulin implants. Treatment with implants worked well. Light microscopic examination of nerve fibres in non-diabetic control rats and in eu-/ hyperglycaemic diabetic rats showed a normal picture. Preparations from eu-/hypoglycemic rats showed irregular myelin sheaths and signs of Wallerian degeneration. The lengths and diameters of the largest internodes were significantly subnormal. We conclude, that periodic moderate hypoglycaemia, but not periodic moderate hyperglycaemia, elicits neuropathy in diabetic BB/Wor rats treated with insulin implants.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 96 (1998), S. 151-156 
    ISSN: 1432-0533
    Keywords: Key words Neuropathy ; Hypoglycemia ; Insulin ; implant ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Insulin-dependent diabetes mellitus is a chronic metabolic disease that causes long-term secondary complications such as neuropathy. The occurrence of diabetic neuropathy has generally been thought of as being associated with hyperglycaemia. However, in a previous light microscopic examination of plantar nerves in diabetic BB/Wor rats treated with insulin implants we found that eu-/hyperglycaemic rats present a normal picture, whereas eu-/hypoglycaemic rats show severe changes. The aim of the present work is to supplement our previous light microscopic report with electron microsocpic data from the lateral plantar nerve of normal, eu-/hyperglycaemic and eu-/hypoglycaemic BB/Wor rats. Under the electron microscope lateral plantar nerves collected from eu-/hyperglycaemic rats presented a qualitatively normal picture. In addition, the fibre numbers and the size distribution of the myelinated fibres were normal. In contrast, specimens from eu-/hypoglycaemic BB/Wor rats showed severe qualitative changes, interpreted as signs of axonal de- and regeneration. The total number of axons was somewhat subnormal and the sizes of the myelinated fibres were strongly shifted towards smaller diameters. These data confirm our previous light microscopic observations. We conclude that eu-/hypoglycaemic BB/Wor rats treated with insulin implants, but not similarly treated eu-/hyperglycaemic animals, develop a neuropathy in their plantar nerves.
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  • 16
    ISSN: 1432-041X
    Keywords: Key words Bombyxin ; Insulin ; Bombyx mori ; Multigene family ; Brain neurosecretory cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Bombyxin G1 gene, a novel insulin-related peptide gene of the silkmoth Bombyx mori, has been identified. The G1 gene encodes a precursor peptide which shows 41–56% and 28% sequence identities with preprobombyxins previously characterized and human preproinsulin, respectively. The G1 gene forms a pair with bombyxin C2 gene with opposite transcriptional orientation in a bombyxin gene cluster. The bombyxin G1 mRNA in Bombyx brain was shown to locate in four pairs of medial neurosecretory cells.
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  • 17
    ISSN: 1432-1076
    Keywords: Key words Diabetes mellitus ; Infantile cystinosis ; Insulin ; C-peptide ; Chronic renal failure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Infantile cystinosis, a rare lysosomal storage disease of cystine, leads to Fanconi syndrome and end-stage renal failure. After renal transplantation, no recurrence of the disease occurs in the graft, but other organ involvement becomes evident later in life. Diabetes mellitus has been associated with cystinosis, but the mechanisms of impaired glucose tolerance have not yet been characterized. Here, we studied glucose tolerance, glucose constant decay (k-values), insulin and C-peptide by intravenous glucose tolerance test (IVGTT) in eight patients with infantile cystinosis (three with impaired GFR (CRF) and five after kidney transplantation (KTX)). For comparison, 15 age-matched children with CRF and 15 age-matched KTX patients were analysed. Both early and second insulin secretion phases were diminished in patients with infantile cystinosis, whereas in CRF, k-values were no different from control patients. After renal transplantation, k-values were significantly lower in cystinotic patients with a markedly reduced early insulin secretion phase. There was a significant negative correlation between k-values and age in patients with cystinosis. Repetitive IVGTTs in these patients demonstrated progressive but rather slow loss of first phase insulin secretion and C-peptide production, suggesting a slowly reducing secretion potential of the beta cell due to cystine storage. Conclusion Unlike type I diabetes mellitus, glucose intolerance in patients with infantile cystinosis is characterized by a slow, progressive loss of insulin secretion and C-peptide production. For these patients, the data indicate a 50% risk of developing glucose intolerance by the age of 18 years. We recommend to perform intravenous glucose tolerance tests at 5-year intervals.
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  • 18
    ISSN: 1432-0738
    Keywords: Key words Proliferation ; Epidermal growth factor (EGF) ; Insulin ; Hepatocyte ; Cyclosporin A
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cyclosporin A (CsA) at concentrations up to 1 μM induced apoptosis in a dose-dependent manner in cultured rat hepatocytes for 48 h in the presence of insulin and epidermal growth factor (EGF). The effect of CsA was evidenced by the DNA fragmentation pattern constituted by fragments of multiples of 180–200 base pairs, which is a characteristic of programmed cell death. The metabolic activity did not change significantly in the presence of 0.1 μM CsA and diminished to 49% of control in the presence of 1 μM CsA. Changes in the metabolic activity were correlated with a decrease in both [methyl-3H]thymidine uptake and DNA content, which reflects a decrease in the cell number. The treatment of cells with CsA (1 μM) decreased the metabolic activity/DNA content ratio by 24% with respect to dimethyl sulphoxide (DMSO) control, which also suggests, under these conditions, that the necrosis achieved is at most only 24%. In addition, the changes observed (apoptotic process, arrest of the cell cycle and apparition of a necrotic process) were correlated with an increase in the high-affinity guanosine triphosphatase (GTPase) enzymes.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 435 (1998), S. 583-594 
    ISSN: 1432-2013
    Keywords: Key words GLP-1 ; cAMP ; Insulin ; Calcium ; NIDDM ; Glucagon ; Islet ; GIP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Glucagon-like peptide 1 is a gastrointestinally derived hormone with profound effects on nutrient-induced pancreatic hormone release. GLP-1 modulates insulin, glucagon and somatostatin secretion by binding to guanine nucleotide binding protein-coupled receptors resulting in the activation of adenylate cyclase and generation of cyclic adenosine monophosphate (cAMP). In the B-cell, cAMP, via activation of protein kinase A, interacts with a plethora of signal transduction processes including ion channel activity, intracellular Ca2+ handling and exocytosis of the insulin-containing granules. The stimulatory action of GLP-1 on insulin secretion, contrary to that of the currently used hypoglycaemic sulphonylureas, is glucose dependent and requires the presence of normal or elevated concentrations of the sugar. For this reason, GLP-1 attracts much interest as a possible novel principle for the treatment of human type-2 diabetes. Here we review the actions of GLP-1 on islet cell function and attempt to integrate current knowledge into a working model for the control of pancreatic hormone secretion.
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  • 20
    ISSN: 1432-5233
    Keywords: Key words Glucose ; Insulin ; Hyperinsulinaemia ; Blood flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Insulin-mediated stimulation of blood flow to skeletal muscle has been proposed to be of major importance for insulin-mediated glucose uptake. The aim of this study was to investigate the relative importance of blood flow and glucose extraction as determinants of insulin-mediated glucose uptake in the human forearm. Forearm blood flow (FBF), glucose extraction and oxygen consumption were evaluated for 100 min during the euglycaemic hyperinsulinaemic clamp (92 mU/l) in nine healthy subjects. FBF was measured by venous occlusion plethysmography. Forearm glucose uptake increased sevenfold during the hyperinsulinaemia (P〈0.001). Forearm glucose extraction showed a minor increase during the first 10 min of hyperinsulinaemia, but the most marked increase took place between 10 and 20 min (+170%). Thereafter, only a minor further increase was seen. During the first 10 min of hyperinsulinaemia FBF was unchanged. Thereafter, FBF increased steadily to a plateau reached after 60 min (+50%, P〈0.001). A close relationship between whole body glucose uptake and FBF was seen at the end of the clamp (r = 0.75, P〈0.02), but at this time the relationship between whole body glucose uptake and forearm glucose extraction was not significant. The modest increase in O2 consumption seen at the beginning of the clamp (+19%) was not related to FBF during the early phase of the clamp. In conclusion, the early course of insulin-mediated glucose uptake in the human forearm was mainly due to an increase in glucose extraction. However, with time the insulin-mediated increase in blood flow increased in importance and after 100 min of hyperinsulinaemia FBF was the major determinant of glucose uptake.
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  • 21
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    Process Safety Progress 17 (1998), S. 61-67 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Risk assessments have been performed to determine the risk associated with the transportation of hazardous wastes through a city. In the course of these assessments, a number of modeling issues arose relating to transportation accident rates, the characterization of incidents, the effect of thermal radiation, the impact of exposure to toxic chemicals, and the threshold for acceptable risk. This paper discusses these issues.
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  • 22
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    Process Safety Progress 17 (1998), S. S3 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 23
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    Process Safety Progress 17 (1998), S. 98-103 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents the design of ribbon wound pressure vessels useful for Ammonia, Urea and Methanol plants. The design is to create a thin shell of 1/5 the total wall thickness required, weld it to the end pieces, and wind 4 to 8 mm thick ribbons of 80 mm width at an angle of 15 to 30 degrees on the inner shell, using a prestress. The ribbons are welded at the ends and an even number of layers are wound cross-helically on to the shell. With more than 7000 vessels over the pressure range of 50 to 350 atmospheres in use in the various chemical industries in China over the past 30 years, their safety record has been excellent. Of particular interest has been the application of this technology in the Ammonia and Urea plants, where the design allows fabrication of these vessels at substantial reduction in cost, and early delivery, when compared to the mono wall technology.
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  • 24
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    Process Safety Progress 17 (1998), S. 20-22 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Most audits try to look at a representative selection of the plant procedures and equipment. An alternative is a survey, a look in depth at selected procedures (such as those for testing alarms and trips, issuing permits-to-work, controlling modifications, taking samples or testing relief devices) or selected equipment (such as level glasses or equipment for handling LPG). If the procedure or equipment is well-chosen, surveys may make a bigger contribution to safety, per person-hour, than a conventional audit.
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  • 25
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    Process Safety Progress 17 (1998), S. 39-42 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Under OSHA 1910.119, all Process Safety Management (PSM) facilities are required to keep their pressure relief system design information current. This article demonstrates why a pressure relief system design verification effort must be based on an equipment list, rather than a relief device list, in order to ensure that every piece of equipment is adequately protected. The formerly common practice of simply checking the design bases of all existing relief devices is deficient is deficient since this technique does not systematically ensure that every piece of equipment is protected.The “Berwanger Method” is a step by step process for designing or analyzing a pressure relief system to meet OSHA 1910.119 Process Safety Information (PSI) and Process Hazard Analysis (PHA) mandates. The method uses a relational database which tracks the relationships between protected equipment, potential overpressure scenarios, and protective devices.The challenge facing an operating company does not end once the design basis has been “verified” - the design basis information must also be maintained and be readily accessible to avoid costly reinvention of the wheel down the road. The “Berwanger Method” also addresses these maintenance issues.
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  • 26
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    Process Safety Progress 17 (1998), S. 49-60 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper reports on a comprehensive literature search and small scale experimental work on the reaction characteristics of phosphorous trichloride and water. More than 30 tests were conducted, including both closed and open test cells. The water to phosphorus trichloride molar ratio was varied from 1 to 25. When in contact, water and phosphorus trichloride will form two liquid layers with a reaction starting at the interface. The impact of variables on reaction rates including the interface surface area, layer depth, and stirring were investigated experimentally. A reaction rate model that fits all the measured data is presented. Case studies illustrating the use of this data for emergency relief systems and vent containment design are presented in reference. [1].
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  • 27
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    Process Safety Progress 17 (1998), S. 68-73 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two major accidents in the 80's: the summit Tunnel Fire, England and Piper Alpha disaster, an offshore platform in the North Sea; and very recently, possible explosion of the Boeing, TWA flight 800 at New York, makes it imperative that further research into the mechonisms of the ignition of flammable vapor/air mixture in contact with hot surfaces needs to be done. There have been a number of studies of ignition by hot surfaces, but in all these studies the ignition sources were wire, sphere or strip, i.e., most of them were flat surfaces. But to the authors' knowledge, other variables which affect the ignition mechanism such as irregular geometrical shapes have not been studied. The purpose of this paper is to examine how the degree of confinement (or, configuration), size and orientation, of the heated surface affects the ignition temperature of the flammable vapors. The results were obtained by experimentnal and by computational fluid dynamics.
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  • 28
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    Process Safety Progress 17 (1998), S. S3 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 29
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    Process Safety Progress 17 (1998), S. 9-15 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The design and deflagration pressure relief vents is based on correlations developed for various types of combustible materials and for enclosures of different strengths. The primary guideline for deflagration vent design in the US is NFPA 68 Guide for Venting of Deflagrations [5]. That document gives guidance for the design of vents for enclosures containing flammable gases, specifically hydrogen, coke oven gas, propane, and methane. Application of the guide to other gases is achieved using the KG value. Values of KG are published for a relatively small number of gases, as seen in Table D-1 of NFPA 68. This work present KG data on several additional gases obtained in a laboratory scale test vessel along with analysis of the results with respect to published values of fundamental burning velocity.
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  • 30
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    Process Safety Progress 17 (1998), S. 23-31 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In May 1996, the Flammable and Combustible Liquids Code Committee of the National Fire Protection Association (NFPA) proposed for adoption by the Association a new edition of NFPA 30, Flammable and Combustible Liquids Code. This new edition was the culmination of two and one-half years' work by the Committee and included one of the most significant changes to that document in some twenty years: the incorporation of mandatory fire protection criteria for warehouses and other inside areas that store flammable and combustible liquids in containers and portable tanks.
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  • 31
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    Process Safety Progress 17 (1998), S. 32-38 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper describes the development of a risk ranked Inspection Recommendation procedure that is used by one of Exxon's chemical plants to prioritize repairs that have been identified during equipment inspection.As part of the Company's Safety Management Practices initiative in the late 1980's a procedure was put into place to ensure that an Inspector's repair recommendations were properly addressed by the organization. The initial procedures were successful at “systematizing” the documentation and stewardship-to-completion of the Inspector's recommendation, however, there were complications with the original process: (1)The Inspector made a simple High, Medium or Low assessment of the priority/criticality of the recommendation. Frequently, this resulted in disagreements with Operations about the true priority of the recommendation.(2)If there was agreement on the priority of the recommendation, there was still disagreement on the relative rank within the priority-which high priority was the highest priority?(3)With limited funds to spend on repairs, it was (and is) important to make sure that the money was being spent on the highest risk items that had the greatest risk reduction/cost benefit ratio.To address these concerns, the procedure was modified to incorporate a risk assessment of the recommendation by both the Inspector and Operations. In the new procedure, the Inspector describes the deficiency that he/she finds and assesses the probability of failure within a certain time-frame. Operations must assess the consequences, from an environmental, safety and economics standpoint, were the failure to occur. These assessments are combined in the typical risk equation (risk = probability × consequences) to arrive at a severity index which serves to rank the recommendation relative to the other recommendations. Because Operations participates in the assessment there is very little disagreement about the priority of the recommendation. The severity index puts the recommendations in order so it is quite clear which are the highest priority recommendations. This process has helped to focus the entire organization on those deficiencies that represent the greatest risk with the result that less time and money is spent correcting items that have a low risk/cost benefit ratio, allowing these savings to be used to reduce the higher risks in the plant.
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  • 32
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    Process Safety Progress 17 (1998), S. 124-126 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple analytical method is presented for estimating the hybrid minimum ignition energy (HMIE) of dust-gas mixtures, based on the assumed generality of Bartknecht's well-known test data for mixtures of propane with a series of dusts in air. Since the HMIE equation requires input data which might be unavailable, the use of conservative default methods is discussed.
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  • 33
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    Process Safety Progress 17 (1998), S. 138-148 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A large and potentially hazardous decrease in aldehyde autoignition temperature (AIT) occurs with increased pressure. The AIT-pressure curve determined in a 5 L stainless steel sphere was similar for propionaldehyde and butyraldehyde in air, falling from about 185°C at atmospheric pressure to 90°C at 140 psia. Reduction of oxygen concentration had little effect on propionaldehyde AIT. At 100°C and 140 psia, autoignitions accompanied by at least a doubling of pressure were observed above 4% oxygen. In the presence of a few grams of free liquid, propionaldehyde vapor ignited in air at initial conditions significantly below the AIT. The mechanism appears to involve rapid Fe-catalyzed exothermic liquid-phase oxidation leading to autoignition of the adjacent heated gas layer. An acetaldehyde vapor-air mixture in the presence of free liquid and rust exploded at room temperature when air pressure was increased to 95 psia; this result is discussed with reference to a cylinder overpressurization that occurred while making up an ostensibly sub-LFL calibration mixture with compressed air. Propionaldehyde's limiting oxygen concentration (LOC) was investigated in the near-autoignition region using the same 5L apparatus; the findings are discussed with reference to an overpressurization incident in an air-liquid partial oxidation reactor. The general results are used to illustrate the application of LOC in partial oxidation processes subject to autoignition and to discuss elements of the current ASTM draft test method for LOC, which does not address test difficulties associated with condensable and/or reactive gas systems.
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  • 34
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    Process Safety Progress 17 (1998), S. F3 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 35
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    Process Safety Progress 17 (1998), S. 157-170 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Risk analysis in chemical process industries is an elaborate exercise involving several steps from preliminary hazard identification to development of credible accident scenarios, to preparation of strategies for prevention or control of damage.All this requires substantial inputs of time and money. In order to get an approximate yet workable assessment of risk at much lesser costs, indices have been developed which link typical findings of elaborate risk analysis to scales of risk. The scales, in turn, provide workable measures of hazards/risks/safety.In the past, indices have been reported for swift risk assessment - the noteworthy among them include Dow fire and explosion index, Mond fire, explosion and toxicity index, IFAL index, and mortality index. A few rapid ranking techniques have also been proposed.This paper presents a new system of methodologies for Hazard Identification and Ranking (HIRA). The system consists of two indices: one for fire and explosion hazards and another for the hazard due to likely release of toxic chemical. The magnitudes of these indices indicate the severity of the likely accident; in terms of the size of the impacted area.HIRA has been applied to a typical chemical process industry - a sulfolane plant - and its performance has been compared with that of the Dow's and the Mond's indices. The study reveals that HIRA is more sensitive and accurate than the other indices.
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  • 36
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    Process Safety Progress 17 (1998), S. 200-208 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 14 Ill.
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  • 37
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    Process Safety Progress 17 (1998), S. 213-218 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: On October 31, 1987 a crane lifting a heat exchanger convection section failed and severed a 4″ loading line and a 2″ pressure relief line to an HF alkylation reactor settler drum at a petroleum refinery in Texas City, Texas. Vapors were emitted under pressure for about two hours and the vessel was plugged and drained aproximately 44 hours later. A plume from this accidental release passed through residential areas, damaging some vegetation (brown lawns), and spawning a class action law suit. An extensive analysis was conducted to determine the total inventory loss and to model the blowdown process and the concentrations of HF in the plume. Since the discharge rate was decreasing with time, a peak concentration of HF in the emitted vapors occurred just before the water spray mitigation system became fully operative. Consequently, the mitigation efforts were more effective late in the response when concentrations were already low. The predicted plume concentrations are consistent with observed vegetation damage effects, with concentrations below Emergency Response Planning Guideline Level 3 past 3/4 mile from the source. These results support a policy of sheltering in place during such an event.
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  • 38
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A fifty-five gallon steel drum of a liquid organic peroxide pressurized and ruptured in the mix room of a manufacturing plant. The head of the drum blew off and the ejected material ignited. The resulting fire was extinguished by the building sprinkler system and operating personnel. Although there were no injuries, the fire caused significant damage in the mix room. The investigation of this incident, its likely cause, and the corrective actions will be discussed.
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  • 39
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    Process Safety Progress 17 (1998), S. 238-242 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Brazoria County Petrochemical Council, 13 companies that are working together to enhance relations between industry and the community, united in a joint effort at complying with the EPA's Risk Management Program. One of the significant issues the group had to address was the need to develop meaningful hazard assessment for presentation to the public. The EPA's “Table Look-Up Approach” found in the Offsite Consequence Analysis Guidance document is certainly a good tool; however, the built-in conservatism results in over-estimates of potential hazard areas. Much more meaningful results are shown to be obtained using one of the hazard release models.The value of using a credible scenario with realistic meteorological data is demonstrated through the consistently smaller areas predicted by the PHAST Model for planning purposes. Realistic scenarios/failure modes and realistic model parameters are important so that the risk to the public is not overstated. Proprietary models such as PHAST are invaluable in providing more meaningful consequences for planning purposes.
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    Process Safety Progress 17 (1998), S. 263-271 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Some of the hazards encountered by process plant operators involve the operation of in-line valves to control, start, and to stop flow. Torque required to operate valves may vary according to valve wheel size, in-line pressure, and valve flange position (open/closed). This study determined how valve wheel size, in-line pressure and valve position (open/closed) affect torque required to actuate a valve. Data were gathered with each combination of size, pressure and position for 336 valves in an operating petrochemical process facility. The results indicate that the main effects of valve wheel size, the in-line pressure, and open/closed valve position significantly affect operational torque requirements. In addition, the interaction between position and pressure was significant for operational torque. The implication of these results is that operators are exposed to operational torque requirements that exceed maximum acceptable capabilities that have been determined in previous studies.
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  • 41
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    Process Safety Progress 17 (1998), S. 288-296 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An ammonia storage tank was built at the BASF Antwerp site in 1969 on land reclaimed from the sea. After several years of operation uneven foundation settlement, of up 2, occurred. In order to assure stability of this area for the next operation period (at least 10 years) measures were taken to ensure continued safe operation. One key measure was strain gauge monitoring at the location of maximum stress.
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  • 42
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    Process Safety Progress 17 (1998), S. 297-301 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Baker-Strehlow methodology was developed to provide an objective approach to prediction of blast pressures from vapor cloud explosions. The complete methodology was first published in 1994 [1]. Since then, it has evolved through ongoing research and use in VCE hazard analyses, facility siting studies and accident investigations. This article gives a brief overview of a paper on recent developments in the Baker-Strehlow methodology presented at the 31st Loss Prevention Symposium in Houston on March 9-13, 1997. Because the entire paper is too lengthy to be presented here, the following discussions may be lacking in some details. A copy of the complete paper can be obtained from the American Institute of Chemical Engineers (AIChE).Since the Baker-Strehlow method was first published, it has been used extensively in VCE hazard assessments in refineries and chemical plants. As expected, many practical lessons have been learned during the course of the hazard assessments, and the Baker-Strehlow method has evolved as a result. The changes have been evolutionary, not revolutionary. In keeping with the goals of the original study in which the methodology was developed, all changes have been incorporated with the intent of achieving an objective methodology to provide consistent prediction of VCE blast effects.The revisions to the Baker-Strehlow method resulting from experience gained during plant walk-downs and hazard assessments include: Systematic identification of “potential explosion sites” or “PESs,”Selection of the level of confinement for mixed zones of 2D and 3D confinement,Deciding on flame expansion when confinement is elevated above the vapor cloud,Selecting the reactivity for a fuel that is a mixture of fuels with differing reactivities,Predicting blast loads when there are multiple PES's within a vapor cloud considering different ignition source locations.
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    Process Safety Progress 17 (1998), S. 83-85 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Safety, health and loss prevention are major areas of interst for the American Institute of Chemical Engineers (AIChE). There has been an evolution of these concerns over the years in the Institute just as it has in industry. This article chronicles this evolution.
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  • 44
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    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 45
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    Process Safety Progress 17 (1998), S. 1-8 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Recent guidelines released by the U.S. EPA define a worst-case scenario as a release under stable atmospheric conditions defined as Pasquil-Gifford stability class F. Unfortunately, very few tests at F stability have been available heretofore to provide a basis for models. Recent test data with propane releases by the German research organization TUV provide a set of 60 experiments conducted specifically to define the effects of atmospheric stability class on dispersion. Of these, 25 tests were at F stability. A comparable number were at each other stability class A through E. In addition 23 tests were at wind speeds under 1.5 m/s in stable atmospheres. This paper reports on adjustments made to our models based on these new data by reducing the originally-postulated sensitivity to stability class. In spite of considerable scatter in the TUV data, particularly between two different types of propane analyzers, the model allows us to extract information by averaging over the tests.
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    Process Safety Progress 17 (1998), S. 16-19 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A multi-disciplinary team developed a guideline for determining access restriction zones around vented solids handling equipment. The guideline provides a method for ensuring the discharge from a vented explosion will not cause injury to personnel. The steps in this method include: calculating the extent of external hazards from vented explosions; identifying potential areas where personnel could be exposed to a hazard; identifying ways to eliminate or reduce the hazard area; and establishing and documenting any access restrictions needed. Hazard zone calculations use the latest knowledge from research into fireball size, flame length and external pressure equations in VDI 3673. The guideline provides guidance for using this information. Options for mitigating or reducing external hazards from vented explosions are also described. As part of the project, the team audited several solids handling systems to look for potential oversights in existing restricted access areas. Some of the team's learnings from these audits are reviewed.
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  • 47
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    Process Safety Progress 17 (1998), S. 43-48 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper defines situation awareness (SA) and discusses its importance to operator-machine system safety and functioning in the context of process control activities. Specifically, identified are relationships of human detection of critical process cues converying the status of automated control systems and operator interpretation of the meaning and relevance of such information to the potential for negative incidents in chemical processing. Beyond individual operator SA in interacting with control systems, intra- and inter- work team SA are discussed for supporting individual attainment of process control responsibilities. Factors critical to team SA are discussed. “Road blocks” to team SA are also analytically examined. Lastly, methods for assessing individual and team SA are reviewed and vehicles for relating outcomes of these methods to changes in process control operator and team behavior to improve human-machine system safety and performance are relayed.
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  • 48
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    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 49
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    Process Safety Progress 17 (1998), S. 74-81 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The knowledge of the ingition behavior of dust-air mixtures due to electrical sparks (MIE, Minimum Ignition Energy) and hot surfaces (MIT, Minimum Ignition Temperature) is important for risk assessments in chemical production plants. The ignition behavior determines the extent and hence the cost of preventive protection measures.This paper describes the use of the minimum ignition energy and minimum ignition temperature as very important safety indexes in practice.Based on the latest results from large scale experiments on pneumatic filling of silos with polymeric materials and new results of full scale filling tests using Flexible Intermediate Bulk Containers (FIBC) manufactured from a variety of materials, guidance can be given to ensure safe operation in different situations such as filling, emptying operations, type of powder handled.The aim of this paper is to assist people dealing with product. It reflects the present state of the art and current knowledge of the assessment and measures associated with powder handling.
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  • 50
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    Process Safety Progress 17 (1998), S. 104-106 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In mid-1997, an Advanced Process Control (APC) scheme was implemented at a resins manufacturing complex with the goal of minimizing flare fuel gas usage while maintaining sufficient energy (BTU/SCF flare gas) to be in environmental regulatory compliance. Prior to APC implementation, the flare system was manually controlled by plant operators with minor attention paid to the minimization of fuel gas usage. Since implementation, APC has saved the plant thousands of dollars in fuel gas costs and reduced unnecessary combusted fuel gas emissions.Hazard analysis techniques were used in the development of the control scheme. An overview of the APC used, the economic evaluation, and the hazard analysis techniques used in the project are presented here.
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  • 51
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    Process Safety Progress 17 (1998), S. 107-123 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the risk assessment parlance, especially with reference to chemical process industries, the term “domino effect” is used to denote “chain of accidents,” or situations when a fire/explosion/missile/toxic load generated by an accident in one unit in an industry causes secondary and higher order accidents in other units. The multi-accident catastrophe which occurred in a refinery at Vishakhapatnam, India, on September 14, 1997, claiming 60 lives and causing damages to property worth over Rs 600 million, is the most recent example of the damage potential of domino effect.But, even as the domino effect has been documented since 1947, very little attention has been paid towards modeling this phenomena. In this paper we have provided a conceptual framework based on sets of appropriate models to forecast domino effects, and assess their likely magnitudes and adverse impacts, while conducting risk assessment in a chemical process industry. The utilizability of the framework has been illustrated with a case study.
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  • 52
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    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 53
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    Process Safety Progress 17 (1998), S. 149-154 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article deals with fire protection for water miscible flammable liquids stored in plastic containers packaged in boxes located on pallets. A series of fire tests was conducted with palletized rack storage arrangements using in-rack sprinkler protection at various levels. The intent of the paper is to present data from this test series for these types of commodities. The paper will identify various existing water miscible flammable liquid products stored in this fashion and provide background information for protecting this type of storage as it relates to NFPA 30 Flammable and Combustible Liquids Code. The test data indicates that further research work is needed in the area of plastic containers for use with the storage of combustible and flammable liquids. Included in the paper are discussions concerning possible protection strategies and suggestions for future research which would benefit those involved in risk management of this type of commodity.
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  • 54
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    Process Safety Progress 17 (1998), S. 176-183 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The safest method to prevent fires and explosions of flammable mixtures in the first place. This method requires detailed knowledge of the flammability region as a function of the fuel, oxygen, and nitrogen concentrations. A triangular flammability diagram is the most useful tool to display the flammability region, and to determine if a flammable mixture is present during plant operations.This paper describes how to draw and use a flammability diagram. A procedure to estimate the flammability region using the available and sometimes limited data is discussed. The paper also shows how to use the flammability diagram with plant operations involving inerting and purging, and from bringing vessels into and out of service. A compilation of flammability diagrams for 30 materials, based on previously published data is provided.An automated apparatus for acquiring data for a flammability diagram is described. The apparatus consists of a 20-L sphere with an automated gas mixing system, a fuse-wire ignition system, and a high speed pressure measurement and data acquisition system. Data derived from the apparatus includes flammability limits, maximum pressure during combustion, and the maximum pressure rate. The effect of fuse-wire ignitor dynamics on the results is studied. A flammability diagram for methane drawn from data obtained from the apparatus, is presented.
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  • 55
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    Process Safety Progress 17 (1998), S. 86-97 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Regulatory issues related to material safety have made the accurate measurement and/or prediction of flash points essential. The flash point is one of the major physical properties used to determine the fire and explosion hazards of a liquid. Flash points are used by virtually all governmental entities worldwide to define “flammable” and “combustible” materials for shipping and safety regulations.A model is described here for the calculation of closed cup flash points for multicomponent, single liquid phase, mixtures. The model is based upon rigorous vapor/liquid equilibrium calculations supplemented with information about the lower flammable limits (LFL's) and heats of combustion (ΔHc's) for the mixture's constituent components. The closed cup flash points predicted with this model are typically within ± 5°C of the experimentally reported values. Such a model is useful as a means of verifying experimental data and as a tool for screening product formulations prior to experimental flash point determination. The model should considerably enhance the safety evaluation portion of the product development cycle, thus leading to shortened product time-to-market cycles. While flash points calculated with this model are in excellent agreement with experiment, experimental determination is still encouraged for critìcal safety applications.
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  • 56
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    Process Safety Progress 17 (1998), S. 134-137 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: National Advisory Committee's Acute Exposure Guideline Levels (AEGLs) for ammonia are critically evaluated. The technical bases for concern about AEGL-2 and AEGL-3 values derived by the committee are summarized recommendations made.
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  • 57
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    Process Safety Progress 17 (1998), S. 127-133 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An explosion and flash fire in a fixed bed reactor occurred at a municipal wastewater treatment plant (WWTP). Two employees were injured in the accident. The accident occurred in an ozone treatment building where ozone was used to treat odors from the offgas of the sludge concentration units. Excess ozone manually was routed to the fixed bed reactor (ozone destruct unit) where the ozone is catalytically transformed into oxygen before being discharged to the atmosphere.An investigation of the accident was conducted to determine the root cause of the explosion and flash fire and identify corrective actions which the WWTP management could undertake to prevent a recurrence. This investigation included site inspections, interview with the injured employees, sampling and analysis of various materials, an explosion dynamics analysis, and a root cause analysis.It was concluded that cooling oil from one of the ozone generation units entered the main ozone gas line due to a crack in one of the reactor's dielectric tubes. The cooling oil was vented into the ozone destruct unit when an employee opened a ball valve on the main ozone gas line. The cooling oil, essentially a saturated hydrocarbon mixture, reacted exothermically when it contacted the manganese dioxide catalyst. The exothermic reaction resulted in an explosion which propelled the access panel outwards and dispersed the catalyst pellets. A flash fire followed the explosion. The flash fire burned two employees and caused thermal damage to a nearby control panel.Although this accident was the first of its kind at this facility, this was not the first time that the ozone generator had experienced a failure of a dielectric tube. Thus, there was a significant probability that a dielectric tube failure could leak cooling oil into the main ozone gas line. This failure event could, in turn, result in another explosion and flash fire. The WWTP staff neither designed nor fabricated the ozone generator-destructor system. Therefore, it did not seem appropriate for the WWTP staff to modify the ozone system. Instead, it was recommended that the ozone destruct unit be taken out of service. The WWTP management acted on this recommendation.
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  • 58
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    Process Safety Progress 17 (1998), S. 171-175 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An explosion occurred in a petroleum product storage tank at a refinery. The liquid petroleum product was a heavy oil used as an asphalt extender. There were no injuries, but the cleanup was costly. The storage tank was one of several which received the product stream from a dehydration unit. The accident occurred shortly after the refinery was brought back on-line following a shutdown for schduled maintenance.This was the first incident of this kind to occur at this facility. Analysis of the process data and eyewitness observations indicated that the dehydration tower, which was supposed to be maintained at a minimum of 100°C during the shutdown, was allowed to drift below 100°C for an unknown period of time. This deviation enabled liquid water to enter the storage tank. Three operational factors contributed to the accident. Corrective actions were recommended to prevent a recurrence of a similar incident.
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  • 59
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    Process Safety Progress 17 (1998), S. 184-189 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dust explosions have been with us for a long time. The first record of a dust explosion occurred in Turin, Italy, on December 14, 1785 [1]. The detailed record of this event is left to us by Count Morozzo. The event took place in Mr. Giacomelli's bakery. We know from his account that the weather was unseasonably dry, that a boy who worked in the bakery was using a shovel to stir and transfer the flour to a chute from a store room to the bakery and he had a lighted lamp to work by. The rest, as the saying goes, is history. No one was killed, and the building was saved by the sagacious fact of having plenty of windows. Since that first record, of course, there have been many explosions with much loss of life and significant economic consequences.
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  • 60
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    Process Safety Progress 17 (1998), S. 190-195 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The RSST DIERS vent sizing methodology is revised to provide realistic design equations for reactive systems consistent with available large-scale experience. Using easy to obtain RSST data such as rate of temperature rise and rate of pressure rise excellent agreement is illustrated for hybrid, vapor and gassy reactive systems.
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  • 61
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    Process Safety Progress 17 (1998), S. 196-199 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: From the 1960s onwards, the chemical and oil industries developed and used a number of new safety techniques which, in time, became second nature to those who applied them. They included the use of QRA for deciding priorities, Hazop and audits for identifying problems, inherently safer design for avoiding hazards, and more thorough investigation of incidents for identifying underlying causes. However, it has not yet become second nature to remember the accidents of the past and the actions needed to prevent them happening again.I joined industry in 1944 and moved to production in 1952. Then, and for at least 15 years afterwards, safety was a non-technical subject that could be left to arts graduates and elderly foremen. There was concern that people should not be hurt - great attention was paid to the lost-time accident rate - but there was no realization, that it was a subject worthy of systematic study by experienced technologists.This view changed at the end of the 1960s. A new generation of plants had been built, operating at higher temperatures and pressures and containing larger inventories of hazardous chemicals; the result was a series of fires and explosions and a worsening fatal accident rate. Figure 1 shows the situation in ICI, at the time the UK, s largest chemical company. Other companies experienced a similar state of affairs.As a result in 1968, I was appointed one of the company's first technical safety advisers, an unusual appointment at the time for someone with my experience, and if the reason for my appointment had not been so obvious I would have wondered what I had done wrong. I and my colleagues tried to apply the same sort of systematic thinking to safety that we applied in our other professional work. We developed some new concepts and techniques and adopted others. A common feature of our ides, realized only in restrospect, was that they consisted of more than mere problem-solving techniques. Once people had got used to these new concepts and used them a few times, they began to look at a whole range of problems in a different way.
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  • 62
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    Process Safety Progress 17 (1998), S. W3 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 63
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    Process Safety Progress 17 (1998), S. 259-262 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Case histories of 65 incidents in runaway reactions and emergency relief in Taiwan were analyzed and classified into several categories according to their causes, materials involved, equipment types, reaction types, and ignition sources. The cases in reactors and storage tanks were examined in more detail owing to the higher probability or larger potential hazard in these two types of equipments. The most common consequence of the incidents are explosions, fires, and atmospheric release of toxic chemicals. The most severe case was a thermal explosion from an organic peroxide storage area which caused the death of 33 persons. Popping and direct releasing of process chemicals to the atmosphere from relieving devices cause the greatest environmental concerns to the community close to the plants. Runaway reactions in batch type reactors occur frequently due to various operational mistakes. Heat of reaction is the most frequent ignition source of runaway reactions and emergency relief.
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  • 64
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    Process Safety Progress 17 (1998), S. 272-277 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: EPA's Risk Management Program regulation, promulgated in June 1996 as 40 CFR Part 68 requires subject industries to submit Risk Management Plans by June 1999. This plan requires hazard assessment of the operations of a facility using worst case scenarios and alternative releases. EPA has provided an Off-site Consequence Analysis (OCA) guidance to help facilities in their hazard assessment.OxyChem will be significantly impacted by the RMP rule. This paper outlines OxyChem's general experience and its strategy in planning to comply with this rule. OxyChem's approach in the development of the scenarios required by the rule is described in this paper. Limitations involved in the use of EPA's look-up tables or a single modeling solution for conducting all of the OCA are discussed. A three tiered OCA approach is presented as a possible alternative.
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  • 65
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    Process Safety Progress 17 (1998), S. 209-212 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: HFC-227ea (CF3CHFCF3;1, 1, 1, 2, 3, 3, 3-heptafluoropropane) is an effective replacement for Halon 1301 in fire suppression systems, providing rapid extinguishment of flames through a combination of physical and chemical mechanisms. The vast majority of applications for HFC-227ea involve the protection of Class A hazards, which are characterized by low fuel loadings and low energy output, with fire sizes often in the range of 5-10 kW. Mid- and large-scale testing has demonstrated that HFC-227ea, at its minimum design concentration of 7.0% v/v, is effective at extinguishing fires typical of those expected to occur in electronic data processing (EDP) facilities, telecommunication facilities and anechoic chambers. The levels of HF produced following extinguishment of typical Class a fires with HFC-227ea were well below the estimated mammalian LC50 and the human Dangerous Toxic Load (DTL), and do not appear to present a threat to electronic equipment.
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    Process Safety Progress 17 (1998), S. 219-224 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sandia National Laboratories (Sandia) has refined a process for developing inherently safer system designs based on methods used by Sandia to design detonation safety into nuclear weapons. The process was created when Sandia realized that standard engineering practices did not provide the level of safety assurance necessary for nuclear weapon operations, with their potential for catastrophic accidents. A systematic approach, which relies on mutually supportive design principles integrated through fundamental physical principles, was developed to ensure a predictably safe system response under a variety of operational and accident-based stesses. Robust, safe system designs result from this thematic approach to safety, minimizing the number of safety critical features. This safety assurance process has two profound benefits: the process avoids the need to understand or limit the ultimate intensity of off-normal environments and it avoids the requirement to analyze and test a large array of accident environment scenarios (e.g., directional threats, sequencing of environments, time races, etc) to demonstrate conformance to all safety requirements.
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    Process Safety Progress 17 (1998) 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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    Process Safety Progress 17 (1998), S. 233-237 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new method is described to enhance the management of process safety risks such that the number and type of safety systems protecting against any hazard are consistently predicated upon risk. Further, that such an assignment of safety systems can be made consistent throughout an organization. This consistency is gained through standardization of qualitative risk ranking and by setting company guidelines.
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  • 69
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    Process Safety Progress 17 (1998), S. 243-258 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Research was carried out to develop improved protection guidelines for silane handling systems through enhanced understanding of the behavior of releases of this pyrophoric gas. The approach involved addressing three aspects of the problem: the prompt ignition behavior of silane; the reactivity characteristics of quiescent silane/air mixtures; and the rates of reaction of silane leaked into enclosures with and without explosion venting, in the presence of ventilation air flow. A first conclusion, reached from tests in a ventilated cabinet, was that, contrary to prevailing belief, the ventilation flow has no measurable effect on the prompt ignition of the release. From experiments in a 5.1-liter (311-in.3) sphere it was found that silane/air mixtures of concentrations between 1.4 and 4.1% (by volume) are explosive but stable. In this case, piloted ignition tests yielded laminar burning velocities up to 5 m/s (1000 ft/min). Mixtures between 4.5 and 38% (the maximum reached in the tests) were found to be metastable, and would undergo spontaneous ignition after a delay ranging from 15 to 120 seconds, with the shorter values corresponding to higher silane concentrations. Experiments were also performed in a 0.645-m3 (22.8-ft3) vessel both with and without explosion venting, to measure the rates of energy release associated with impulsively-started silane leaks from 1/8 and 1/4-in. (3.2 and 6.4-mm) lines. A method for the prediction of the venting requirements of partial-volume deflagrations (PVD) was evolved into a tool to quantify the pressure rise from ignition of silane leaks in enclosures. These results represent a significant step toward updating existing design recommendations which prescribe ventilation requirements that are based on outdated and, in some instances, misinterpreted data.
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    Process Safety Progress 17 (1998), S. 278-287 
    ISSN: 1066-8527
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gas explosion simulators are often used as tools in process plant design. This article presents some properties of gas explosions found using the EXSIM simulation software on three offshore modules with a total of nearly 10,000 simulations. The selected results are chosen for their supposed applicability to structural design in the process industries.Generalized data are presented for the effect of gas cloud size, explosion impulse vs. explosion pressure, pressure and impulse vs. duration, the probability of a “short” explosion, loading rate, pressure-time “shape” function, and the effect of introducing louvers.
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    Journal of molecular medicine 75 (1997), S. 327-340 
    ISSN: 1432-1440
    Keywords: Key words Pancreas ; Islet ; β Cell ; Insulin ; Transcription ; PDX-1 ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The pancreatic β cell is the major source of circulating insulin in adult mammals. In the multistep process of insulin synthesis it is initiation of transcription that restricts insulin synthesis to the β cell since all subsequent steps can be performed by other cell types. Many of the transcription factors that bind to the insulin promoter and activate insulin gene transcription have been isolated. Some of these factors are restricted in their expression pattern, but so far no truly β cell-specific transcriptional activator has been found. Since different transcription factors synergize to activate insulin gene transcription, cell-specific transcription of insulin is probably realized through the interactions of a unique set of regulatory proteins in the β cell. The same transcription factors that regulate insulin gene transcription in the adult β cell are involved in determining cell differentiation during pancreatic development. The endocrine and exocrine pancreas form from the gut endoderm as a dorsal and a ventral bud which later fuse to build a single organ. The homeodomain protein PDX-1, an insulin gene transcription factor, is uniformly expressed in the early pancreatic bud, and null mutation of PDX-1 in mice results in a failure of the pancreatic bud to grow and differentiate. Other transcription factors, such as the helix-loop-helix protein Beta-2 and the homeodomain protein Nkx 6.1, show a restricted pattern of expression during embryogenesis and in the mature islet. Those proteins may serve a dual role for the organism: during embryogenesis they may determine islet cell differentiation and in the adult they may ensure tissue-specific expression of the islet cell hormones. A better understanding of the factors involved in insulin gene transcription and islet cell differentiation will ultimately provide the basis for novel therapy of diabetes.
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  • 72
    ISSN: 1434-0879
    Keywords: Phosphaturia ; Glucose ; Insulin ; lipids ; Idiopathic recurrent calcium urolithiasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous work in younger males with recurrent idiopathic calcium urolithiasis (RCU) demonstrated inappropriately high postprandial phosphaturia, hyperinsulinemia and insulin resistance, but normal glycemia. To investigate further whether these abnormalities occur also in RCU patients with a mean age corresponding to the life period with peak formation of calcium-containing stones, two trials were carried out in 155 males of comparable age and body mass index. All participants underwent a standardized laboratory examination, including collection of urine and blood before and following a test meal rich in carbohydrate and calcium but low in phosphorus. In trial 1, comprising control subjects (n = 12, mean age 42 years) and RCU patients (n = 24, mean age 41 years), phosphate (Pi) excretion and fractional Pi excretion in postprandial urine of controls did not change compared with the values in fasting urine, but were significantly increased in RCU, despite the fact that there was almost equal suppression of serum parathyroid hormone (PTH) and increase in serum calcitonin. Postprandially, RCU patients were hyperinsulinemic but still normoglycemic versus controls. In trial 2, carried out in unclassified (in terms of calciuria) RCU patients (n = 119, mean age 40 years) only, the post-load Pi-uria was similar in magnitude to Pi-uria of RCU patients in trial l; increased postprandial Pi-uria was a phenomenon also of normocalciuria but was slightly more pronounced in hypercalciuria, while changes in calcium phosphate (brushite) and calcium oxalate supersaturation of urine were unrelated to calciuria. In RCU patients, but not controls, there was a tendency toward higher urinary glucose in post-load as compared with fasting urine. When urinary Pi and fractional Pi excretion in trial 2 were considered as dependent variables in multivariate regression analysis, they appeared unrelated to age, but positively associated with postprandial glycemia as the best predictor, followed by insulinemia, insulin resistance, to a lesser degree fasting serum PTH and the metabolic activity of stone disease, negatively associated with blood total lipids and very low density lipoprotein (VLDL) cholesterol. It was concluded that RCU males (1) show low Piuria during fasting but impaired renal Pi conservation in response to a mixed meal, a situation carrying the risk of Pi deficiency over the long term; (2) represent a population developing hyperei-uria despite suppressed PTH; (3) exhibit insulin resistance but are still able to maintain normoglycemia at the expense of hyperinsulinemia. It is suggested that calcium-containing renal stones are related to impaired Pi and glucose translocation across cell membranes, and that the role of lipids in this setting deserves further investigation.
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  • 73
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    Journal of biomedical science 4 (1997), S. 295-299 
    ISSN: 1423-0127
    Keywords: Hepatoma ; Hepatitis B surface antigen ; Insulin ; Glucocorticoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have shown previously that insulin suppresses the expression of hepatitis B surface antigen (HBsAg) gene from an endogenous integrated viral genome in cultured human hepatoma Hep3B cells. In this study, we demonstrated that insulin suppresses the viral mRNA transcribed from transiently transfected tandem repeat hepatitis B virus (HBV) dimer DNA or DNA fragment that contains only the major HBsAg gene. Insulin treatment also resulted in a decrease in HBV viral particles produced by the HBV-DNA-transfected cells in a dose-dependent manner. Furthermore, when insulin was simultaneously added with glucocorticoid, which stimulates HBV gene expression, the stimulatory effect of glucocorticoid was completely abolished. Our results suggest that insulin has a dominant negative effect on the HBV gene expression in cultured human liver cells.
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  • 74
    ISSN: 1432-2013
    Keywords: Key words GLP-1 ; Exocytosis ; B-cell ; Glucagon ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The mechanisms by which glucagon-like peptide 1(7–36)amide (GLP-1[7–36]amide) potentiates insulin secretion were investigated by measurements of whole-cell K+ and Ca2+ currents, membrane potential, the cytoplasmic Ca2+ concentration ([Ca2+]i) and exocytosis in mouse pancreatic B-cells. GLP-1(7–36)amide (10 nM) stimulated glucose-induced (10 mM) electrical activity in intact pancreatic islets. The effect was manifested as a 34% increase in the duration of the bursts of action potentials and a corresponding 28% shortening of the silent intervals. GLP-1(7–36)amide had no effect on the electrical activity at subthreshold glucose con- centrations (≤6.5 mM). In cultured B-cells, GLP-1(7–36)amide produced a decrease of the whole-cell ATP-sensitive K+ (KATP) conductance remaining at 5 mM glucose by ≈30%. This effect was associated with membrane depolarization and the initiation of electrical activity. GLP-1(7–36)amide produced a protein-kinase-A- (PKA-) and glucose-dependent fourfold potentiation of Ca2+-induced exocytosis whilst only increasing the Ca2+ current marginally. The stimulatory action of GLP-1(7–36)amide on exocytosis was mimicked by the pancreatic hormone glucagon and exendin-4, a GLP-1 receptor agonist. Whereas the stimulatory action of GLP-1(7–36)amide could be antagonized by exendin-(9–39), this peptide did not interfere with the ability of glucagon to stimulate exocytosis. We suggest that GLP-1(7–36)amide and glucagon stimulate insulin secretion by binding to distinct receptors. The GLP-1(7–36)amide-induced stimulation of electrical activity and Ca2+ influx can account for (maximally) a doubling of insulin secretion. The remainder of its stimulatory action results from a cAMP/PKA-dependent potentiation of Ca2+-dependent exocytosis exerted at a stage distal to the elevation of [Ca2+]i.
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  • 75
    ISSN: 1432-2013
    Keywords: Key words Na+-K+ pump ; Membrane potential ; Muscle fatigue ; Catecholamines ; Insulin ; Soleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Continued excitation of skeletal muscle may induce a combination of a low extracellular Na+ concentration ([Na+]o) and a high extracellular K+ concentration ([K+]o) in the T-tubular lumen, which may contribute to fatigue. Here, we examine the role of the Na+-K+ pump in the maintenance of contractility in isolated rat soleus muscles when the Na+, K+ gradients have been altered. When [Na+]o is lowered to 25 mM by substituting Na+ with choline, tetanic force is decreased to 30% of the control level after 60 min. Subsequent stimulation of the Na+-K+ pump with insulin or catecholamines induces a decrease in [Na+]i and hyperpolarization. This is associated with a force recovery to 80–90% of the control level which can be abolished by ouabain. This force recovery depends on hyperpolarization and is correlated to the decrease in [Na+]i (r = 0.93; P〈0.001). The inhibitory effect of a low [Na+]o on force development is considerably potentiated by increasing [K+]o. Again, stimulation of the Na+-K+ pump leads to rapid force recovery. The Na+-K+ pump has a large potential for rapid compensation of the excitation-induced rundown of Na+, K+ gradients and contributes, via its electrogenic effect, to the membrane potential. We conclude that these actions of the Na+-K+ pump are essential for the maintenance of excitability and contractile force.
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  • 76
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    Pflügers Archiv 434 (1997), S. 11-18 
    ISSN: 1432-2013
    Keywords: Key words A6 epithelia ; Ouabain binding ; Insulin ; Cycloheximide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The effects of insulin on the Na+-K+-ATPase pump of the basolateral membrane of tight epithelia were evaluated by measuring transepithelial transport and [3H]ouabain binding in cultured A6 kidney cells. [3H]Ouabain binding in epithelia incubated in either K+-containing or K+-free solutions was measured. Insulin induced increases in transepithelial sodium transport, as measured by the short-circuit current (I sc), and in the initial rate of [3H]ouabain binding determined when the preparation was bathed in K+-containing solutions. However, when initial [3H]ouabain binding in tissues incubated in K+-free solutions was measured the stimulation of the initial rate of [3H]ouabain binding caused by insulin was markedly reduced. Incubating the apical side of the epithelium with either amiloride or Na+-free solutions also reduced or abolished the increase in the initial rate of [3H]ouabain binding caused by insulin. Equilibrium binding measurements showed that insulin did not increase the maximum number of [3H]ouabain-binding sites in tissues incubated with either normal K+ or K+-free solutions. These results indicate that the increase in the initial rate of [3H]ouabain binding under transporting conditions is due to an effect on the binding kinetics of ouabain, probably related to an increased rate of Na+ entry, rather than to an increase in the number of Na+-K+-ATPases in the basolateral membrane. Cycloheximide inhibited both the increase in I sc and the increase in the initial rate of [3H]ouabain binding caused by insulin in epithelia incubated in K+-containing solutions. However, cycloheximide was without effect on the initial rate of [3H]ouabain binding in insulin-treated tissues incubated in K+-free solution. This finding suggests that the cycloheximide-sensitive step of the action of insulin is related to Na+ delivery to the pump.
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  • 77
    ISSN: 1439-6327
    Keywords: Key words Glucose ; Insulin ; Epinephrine ; Lactate ; Force-velocity test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated metabolic and hormonal responses during repeated bouts of brief and intense exercise (a force-velocity test; Fv test) and examined the effect of glucose ingestion on these responses and on exercise performance. The test was performed twice by seven subjects [27 (2) years] according to a double-blind randomized crossover protocol. During the experimental trial (GLU), the subjects ingested 500 ml of glucose polymer solution containing 25 g glucose 15 min before starting the exercise. During the control trial (CON), the subjects received an equal volume of sweet placebo (aspartame). Exercise performance was assessed by calculating peak anaerobic power ( W˙ an,peak). Venous plasma lactate concentration increased significantly during the Fv test (P 〈 0.001), but no difference was found between CON and GLU. Blood glucose first decreased significantly from the beginning of exercise up to the 6-kg load (P 〈 0.001) and then increased significantly at W˙ an,peak and for up to 10 min during the recovery period (P 〈 0.001) in both CON and GLU. Insulin concentrations decreased significantly in both groups, but were higher at W˙ an,peak in GLU compared with CON (P 〈 0.05). Glucagon and epinephrine did not change significantly in either group, but epinephrine was significantly lower in GLU after glucose ingestion (P 〈 0.05) and at W˙ an,peak (P 〈 0.05). W˙ an,peak was not significantly different between CON and GLU. In conclusion, blood glucose and insulin concentrations decreased during repeated bouts of brief and intense exercise, while blood lactate concentration increased markedly without any significant change in glucagon and epinephrine concentrations. Glucose ingestion altered metabolic and hormonal responses during the Fv test, but the performance as measured by W˙ an,peak was not changed.
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  • 78
    ISSN: 1439-6327
    Keywords: Key words Naloxone ; Insulin ; Glucagon ; C-peptide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract β-Endorphin (BE) infusion at rest can influence insulin and glucagon levels and thus may affect glucose availability during exercise. To clarify the effect of BE on levels of insulin, glucagon and glucose during exercise, 72 untrained male Sprague-Dawley rats were infused i.v. with either: (1) BE (bolus 0.05 mg · kg−1 +0.05 mg · kg−1 · h−1, n = 24); (2) naloxone (N, bolus 0.8 mg · kg−1 + 0.4 mg · kg−1, n = 24); or (3) volume-matched saline (S, n = 24). Six rats from each group were killed after 0, 60, 90 or 120 min of running at 22 m · min−1, at 0% gradient. BE infusion resulted in higher plasma glucose levels at 60 min [5.93 (0.32) mM] and 90 min [4.16 (0.29) mM] of exercise compared to S [4.62 (0.27) and 3.41 (0.26 mM] and N [4.97 (0.38) and 3.44 (0.25) mM]. Insulin levels decreased to a greater extent with BE [21.5 (0.9) and 18.3 (0.6) uIU · ml−1] at 60 and 90 min compared to S [24.5 (0.5) and 20.6 (0.6) uIU · ml−1] and N [24.5 (0.4) and 21.6 (0.7) uIU · ml−1] groups. Plasma C-peptide declined to a greater extent at 60 and 90 min of exercise with BE infusion compared to both S and N. BE infusion increased glucagon at all times during exercise compared to S and N. These data suggest that BE infusion during exercise influences plasma glucose by augmenting glucagon levels and attenuating insulin release.
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  • 79
    ISSN: 1573-7284
    Keywords: Elderly ; Health-status ; Insulin ; Lipids ; Metabolic-syndrome ; Survival
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The clinical significances of different components of the multiple metabolic syndrome were studied in a five-year follow-up study of random persons (n = 1,199) of four birth cohorts at ages 65, 75, 80, and 85 years. The subjects were examined clinically and their serum lipids, blood glucose, plasma insulin, blood pressure, and health score were determined. The health score was measured using a visual analogue scale. All subjects were followed for 5 years. Health score, diastolic blood pressure and body mass index declined over age, but serum triglycerides, and blood glucose were similar, whilst serum high density lipoprotein (HDL)-cholesterol increased. Among women fasting plasma insulin was lowest in the age group of 65 years. The associations of components of the multiple metabolic syndrome varied by age. In the age groups of 65 and 75 years high body mass index, plasma insulin, glucose, triglycerides and low HDL-cholesterol were associated with impaired health. In the age group of 85 years high blood pressure, total cholesterol, and HDL-cholesterol were associated with good health. The baseline health score was consistently lower in the decedents than survivors of all age groups, but components of the metabolic syndrome were generally not associated with impaired survival.
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  • 80
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    Langenbeck's archives of surgery 382 (1997), S. 164-166 
    ISSN: 1435-2451
    Keywords: Key words Cortical bone ; Capillaries ; TEM ; Receptor blockade ; Epinephrine ; Insulin ; Schlüsselwörter Knochenkapillaren ; TEM ; Rezeptorenblockade ; Adrenalin ; Insulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei 3mal sechs Mäusen wurden die α- und β-Rezeptoren mit Phentolamin und Propranolol blockiert. Den 3 Gruppen wurden Kochsalz, Adrenalin und Insulin injiziert. Kortikale Knochenkapillaren aus der Tibiadiaphyse wurden für die TEM aufgearbeitet. Ihre Lumen- und Endothelflächen wurden als Estimator angegeben und gruppenweise verglichen. Signifikante Änderungen wurden nur im Endothel nach Insulin gesehen. Das spricht für spezifische Insulinrezeptoren in der terminalen Strombahn von Knochen und bestätigt frühere Beobachtungen von Adrenalinwirkungen.
    Notes: Abstract In three groups of six mice each, the α- and β-receptors were blocked by phentolamine and propranolol. The mice in the three groups then received an intravenous bolus injection of saline solution, epinephrine, and insulin, respectively. Cortical bone capillaries from the tibia diaphysis were submitted to transmission electron microscopy (TEM). The lumen and endothelium were measured and the results compared. Significant changes were only noted in the endothelium after the administration of insulin. These findings suggest that there are also insulin receptors in bone. Furthermore, they support previous findings in similar studies with epinephrine.
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  • 81
    ISSN: 0009-2940
    Keywords: Alkoxopalladium(II) ; Conformational analysis ; Hydrogen bonding ; Two-dimensional and cage structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of palladium acetate with two equivalents of di- and triethanolamines RN(CH2CH2OH)2 in the presence of a base affords the new chelate-stabilized alkoxo Pd(II) complexes [Pd(OCH2CH2N(R)CH2CH2OH)2] [R = Me (1), Et (2), n-Bu (3), benzyl (4) or CH2CH2OH (5)]. These N,O-ligated complexes are isolated in high yield as yellow, crystalline solids and are thermally stable despite the presence of several β-hydrogen atoms in the ligand system. Both complexes possess a square-planar palladium coordination geometry with the two oxygen atoms positioned mutually trans. The most notable difference in the molecular structures is that 1 forms a two dimensional network of intermolecular O-H≡O hydrogen bonds, whereas 5 forms intramolecular O-H⃛O hydrogen bonds, which cage the palladium center. In solution 1-4 exist as a diastereoisomeric mixture (a racemic enantiomeric pair SNSN, RNRN and a mesomeric form RNSN) in a 1:1 molar ratio, and this ratio is independent of temperature in nonalcoholic solvents, When complexes 1-4 are dissolved in protic solvents (e.g. MeOH) the diastereomeric excess is temperature-dependent due to an exchange process between the meso diastereoisomer and the (racemic) enantiomeric pair. Thermodynamic parameters for this process in a mixture of MeOH-toluene have been determined with NMR and show this process to be influenced by the steric nature of the alkyl substituent (R) on nitrogen. A conformational analysis based on 1H-NMR coupling constants within the N,O-chelate ring of complexes 1-4 provides details on the solution structure of the ring in both diastereoisomers.
    Additional Material: 9 Ill.
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  • 82
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 13-22 
    ISSN: 0009-2940
    Keywords: Carbamates ; Catalysis ; Substituted nitrobenzenes ; Palladium ; Reductive carbonylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The palladium-catalyzed reductive carbonylation of ortho and para-substituted nitrobenzenes has proven to be an attractive route for the synthesis of functionalized carbamates. For the Pd(1, 10-phenanthroline)2(triflate)2 catalyst system, the scope of the reaction has been studied. Substrates with electron-donating substituents at the para position were found to decrease the catalytic activity, most probably as a result of their relatively low oxidizing capacity. the selectivity towards the desired carbamate, however, was increased for these substrates. Under the influence of electron-withdrawing substituents the azoxybenzene and azobenzene derivatives became important side products. Introduction of large steric hindrance at the ortho position of the nitro substrates gave rise to an interesting side reaction, viz. methoxylation of the aromatic ring. The methoxylation reaction appeared to occur on an intermediate species in the catalytic cycle. Several functionalities have shown to be resistant to the reaction conditions required for the conversion ot the nitro group. Especially with 4-nitrobenzoic acid, an extremely high activity and selectivity was found, thus yielding a very convenient synthesis for N-protected amines containing carboxylic acid function.
    Additional Material: 1 Ill.
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  • 83
    ISSN: 0009-2940
    Keywords: Isothiazole complexes ; Dinuclear silver(I) complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of isothiazole-based potential ligands bearing substituents with additional donor sites in the 5-position of the heterocycle was synthesized [3-Me-5-R-C3HNS; R = CH=N(CH2)2py (1), CH=NCH2py (2), CH2N(CH2CH2NEt2)2 (4), (CH2)2SMe (5)]. Upon reaction with AgO3SCF3 they formed complexes [(1)AgOSO2CF3]2 (6), [(2)AgOSO2CF3]2 (7), [(4)Ag]2+2(O3SCF-3)2 (8) and [(5)AgOSO2CF3]2 (9), respectively. 6, 8 and 9 were shown by X-ray structural analyses to consist of dimeric units L2Ag2+2, either discrete (8), coordinated by terminal CF3SO-3 units (6). In 8 and 9 the isothiazole moiety is bonded to the metal center via the ring-N. The coordination potential of the isothiazole heterocycle is discussed.
    Additional Material: 5 Ill.
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  • 84
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 115-118 
    ISSN: 0009-2940
    Keywords: Gold complexes ; Bromonium complex ; Halogenonium complex ; Halogen, two-coordinate ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of (R3P)AuX (X = Cl, Br, I) with [(R3P)Au]+ BF-4 obtained from (R3P)AuCl and AgBF4 in tetrahydrofuran, lead to cationic binuclear gold(I) complexes of the general formula ([(R3P)Au]2X}+ BF-4. A number of chloro- (R = Ph, o-Tol, Mes, Bzl, Et), bromo- (R = Ph, o-Tol, Mes) and iodo-bridged (R = Ph, Mes) complexes of this type have been isolated and identified on the basis of their analytical and spectroscopic data. The crystal structure of bis[(triphenylphosphane)gold(I)]bromonium tetrafluoroborate was determined by single-crystal X-ray diffraction. The cations contain two-coordinate bromine atoms with an Au-Br-Au angle of 96.83(3)°.
    Additional Material: 1 Ill.
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  • 85
    ISSN: 0009-2940
    Keywords: Arene complexes ; Ruthenium compounds ; Electrophilic substitution ; Lithiation ; Catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral or achiral (arene)(COD)Ru complexes can be made by replacing the η6-ligands of (η4-1,5-COD)(η6-1,3,5-cyclooctatriene)Ru (1) or (η4-1,5-COD)(η6-naphthalene)Ru (2) by a suitable arene. This well known reaction has been extended to mono- and dibromoarenes and we report a novel route to substituted (arene)(COD)Ru species, utilizing (bromoarene)-(COD)Ru as starting materials. These facilitate a rapid bromine-lithium exchange reaction with nBuLi at low temperatures and the lithiated species react readily with alkyl chloroformates as electrophiles. By using chiral electrophiles [alkyl = (-)-menthyl] enantiomerically pure or diastereomeric complexes containing CO2R* groups are formed, depending on the symmetry of the original complex. A diastereomeric 1:1 mixture was separated by recrystallization. All (arene)-(COD)Ru complexes tested so far are useful as catalysts for the hydrogenation of simple alkenes at room temperature.
    Additional Material: 3 Ill.
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  • 86
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    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 145-154 
    ISSN: 0009-2940
    Keywords: Fluorocarbons ; C-F bond activation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The main reaction pathways which lead to the breaking of C-F bonds in perfluoroalkanes and -arenes are discussed. Emphasis is placed on recent developments and on the mechanistic patterns that emerge.
    Additional Material: 2 Tab.
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  • 87
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metal-vapor reactions of Co atoms with 1,3-tBu2CpH (1a), 1,3-tBu2CpH (1a), 1,2,4-tBu3CpH (1b) and EtMe4CpH (1c) are described. With 1a the two mononuclear complexes [(η5-tBu2Cp) (η4-tBu2-1,3-cyclopentadiene)Co] (2a) and [(η5-tBu2Cp)2Co] (3a) were isolated, together with the dinuclear cobalt cluster [{(η5-tBu2Cp)Co}2H3] (4a) and trace amounts of the tetranuclear cluster [{(η5-tBu2Cp)CoH}4] (5a). The molecular structures of 3a and 4a were determined by X-ray diffraction. Reaction of 1b with Co atoms afforded a single product, the dinuclear cluster [{(η5-tBu3Cp)Co}2H3] (4b), whose molecular structure was determined by single-crystal X-ray diffraction. Both, 4a and 4b exhibit extremely short Co-Co distances [2.244(1) (4a) and 2.242(1) Å (4b)], as found for the Me5Cp analog [{(η5-Me5Cp)Co}2H3] (4c). Reaction of an isomeric mixture of Me4EtCpH (1c) with Co atoms furnished the mononuclear sandwich [ (η5-Me4EtCp)(η4-Me4Et-1,3- cyclopentadiene)Co] (2b), the trinuclear hydridocobalt cluster [{(η5-Me4EtCp)Co}3H4] (6a) and the tetranuclear hydridocobalt cluster [{(η5-Me4EtCp)Co}4H4] (5c). The molecular structure of 5c was determined by X-ray crystallography and revealed a tetrahedral arrangement of the cobalt atoms. The electrochemical behavior of the dinuclear complexes 4a-4c was studied by cyclic voltammetry. Reversible redox couples were found for all three compounds, with a correlation between the degree of alkyl substitution and their respective cathodic shifts. Compounds 4a and 4b react with CO to yield the mononuclear and dinuclear complexes [ (η5- CpR)Co(CO)2] (R=1,3-tBu2, 1,2,4-tBu3) (7a and 7b) as well as [{(η5-CpR)CO}2(CO)2] (8a and 8b). Reaction of the trinuclear hydridocobalt cluster 6a and its Me5Cp analog 6b with AgBF4 in the presence of PEt3 yielded the heteronuclear clusters [{η5-Me4CPR)Co}3AgP(Et)3H4]+[BF4]- (R=Et, Me) (9a and 9b). 9a was structurally characterized by X-ray crystallography.
    Additional Material: 8 Ill.
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  • 88
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    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 45-48 
    ISSN: 0009-2940
    Keywords: Metallated methyl isopropenyl ether ; Tetrahydrofurans ; 1-Oxabicyclo[4.3.0]heptanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl isopropenyl ether (1) has been metallated at low temperature with a 1:1 molar mixture of n-BuLi/t-BuOK in THF-hexane, and subsequently functionalized with a variety of electrophilic reagents. At temperatures higher than - 30°C, the metallated methyl isopropenyl ether (2) decomposes with formation of allene. When the suspension of 2 is allowed to warm up to room temperature in the presence of an additional equivalent of n-BuLi, the intermediary allene is converted into 1-propynyllithium (2c), which reacts with propylthiocyanate to give 1-propylthio-1-propyne (4). Some of the functionalization products were subjected to acidic hydrolysis affording the expected methyl ketones.
    Additional Material: 2 Tab.
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  • 89
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 55-62 
    ISSN: 0009-2940
    Keywords: Diastereoselective hydrogenation ; Folic acid ; Immobilized optically active rhodium(I)/diphosphane catalysts ; Leucovorin ; HPLC analysis of 5-formyltetrahydrofolic acid derivatives ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For the hydrogenation of the C=N bonds in the pyrazine ring of the vitamin folic acid (1) optically active rhodium(I)/diphosphane complexes immobilized on supports such as silica gel or Al2O3 were used. The reduction was carried out at 50 bar hydrogen pressure in an aqueous solution buffered to pH 7. Thus, 5,6,7,8-tetrahydrofolic acid (2) was obtained which contains a new asymmetric center at C-6 of the pterine system. Therefore, in combination with the (S) configuration of the natural L-glutamic acid part of the molecule two diastereomers with (6S,S) and (6R,S) configuration arise. The relatively unstable tetrahydrofolic acid (2) was converted into its 5-formyl derivative folinic acid (4) by treatment with methyl formate/formic acid in a 5:1 mixture of DMSO/pyridine. The Ca salt of folinic acid (4) is the widely used drug leucovorin. The diastereomers were separated by silica gel HPLC. To the column bovine serum albumine (BSA) is covalently bound. With optically active rhodium(I)/diphosphane catalysts, immobilized on silica gel supports, a diastereoselectivity of up to 90% could be achieved in the hydrogenation of folic acid (1).
    Additional Material: 1 Ill.
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  • 90
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 405-408 
    ISSN: 0009-2940
    Keywords: Hexahydro-closo-hexaborates ; Boron ; Bridging ligands ; NMR spectroscopy ; Gold ; Copper ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By reaction of (PPh3)3 CuCl and PPh3AuCl with [B6H6]2- in organic media, dinuclear complexes are formed containing the hexaborate as a bridging ligand coordinated to the metal centers by opposite B3 facets of the B6 cluster in a trihapto mode. This is verified by single-crystal X-ray structural analysis of the isotypical (Paā) compounds [Cu2μ-bis-η3-B6H6)(PPh3)2] (1) and [Au2(μ-bis-η3-B6H6)(PPh3)2)] (2) which showed the metal centers to be very close to the B3 plane [1.92 (1), 2.10 (2) Å. The 11B NMR spectra of the two compounds feature doublets, at δ= -15.32 in 1 and at -11.51 in 2, which are significantly shifted downfield in comparison to [B6H6]2- (δ= -17.2).
    Additional Material: 2 Ill.
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  • 91
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 425-429 
    ISSN: 0009-2940
    Keywords: Silver complexes ; Crown compounds ; Thioethers ; 1,3-Dithioles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coordination chemistry of two crown thioethers 2,5,8,10,12-pentathiabicyclo[7.3.0]dodeca-1)9)-ene-11-thione (L) and -11-one (L') with Ag1 has been investigated by structural methods. Both thioethers act as tridentate ligands coordinating the silver ion in a trigonal fashion. In the case L, the 11- thione sulfur is coordinated additionally by another silver ion, to yield a polymeric chain with a distorted-tetrahedral geometry about the metal ion. Despite differing only in its carbonyl chalcogen, L' forms six-coordinated, monomeric complexes.
    Additional Material: 3 Ill.
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  • 92
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 433-442 
    ISSN: 0009-2940
    Keywords: Metallobiosites ; Metalloproteins ; Metalloenzymes ; Dinucleating ligands ; Transition metals ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Awareness of the asymmetric nature of numerous dinuclear metallobiosites and of the ability of the individual metal ions to have quite distinct roles in the functioning of the metalloenzyme concerned has led to a search for carefully designed unsymmetric dinucleating ligands that will give dinuclear complexes capable of acting as models for the metallobiosites. This review surveys progress made in the design and synthesis of complexes capable of serving as models for donor atom, coordination number and geometric asymmetries found at dinuclear metal centres.
    Additional Material: 2 Ill.
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  • 93
    ISSN: 0009-2940
    Keywords: Alkali metal organophosphanylamide ; Carbon-potassium bonding ; Phosphazane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metalation of bis(diphenylphosphanyl)amine [HN-(PPh2)2,1 with KOtBu at 95°C in toluene affords a pale yellow precipitate of potassium bis(diphenylphosphanyl)amide (3a). On addition of liquid N,N,N′,N“,N“-pentamethyldiethylenetriamine (PMDTA, 4) the precipitate dissolves in toluene at 115°C to give a yellow solution, from which yellow-green blocks of [(Ph2P)2NK·PMDTA] (3b) are obtained. X-ray analysis reveals that the coordination sphere of potassium consists of the chelating triamine ligand and [N(PPh2)2]- as N-donor as well as η1 and η2 C-donor with two phenyl fragments. No phosphorus coordination of [N(PPh2)2]- is observed.
    Additional Material: 2 Ill.
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  • 94
    ISSN: 0009-2940
    Keywords: Phosphaalkynes ; Triorganoaluminium compounds ; Cooligomerization ; Cage compounds ; Aluminium compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When the trialkylaluminium reagents 5 are allowed to react with phosphaalkynes 4 in n-pentane, a highly selective phosphaalkyne cyclotrimerization with incorporation of two organometallic units occurs (→ 6). The tetracyclooctane derivatives 6a-e represent the first examples of phosphorus-aluminium-carbon cage compounds. The polycyclic products 6 are able to function as ligands in transition-metal complexes (→ 7), which is illustrated by the reactions of 6b, c with nonacarbonyldiiron and pentacarbonyl(tetrahydrofuran)tungsten, respectively.
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  • 95
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 283-289 
    ISSN: 0009-2940
    Keywords: Zinc ; Sulfonate ligands ; Perchlorates ; Coordination modes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempts are reported to incorporate sulfonate and perchlorate anions as ligands in zinc complexes of tripodal ligands. Using tris(benzimidazolylmethyl)amine (BIMA) only the aqua complexes [ (BIMA)Zn-OH2](RSO3)(ClO4) and [(BIMA)Zn-OH2](RSO3)2(R=CH3, CF3, p-tolyl) were accessible. Using substituted pyrazolylborates (Tp*), the same three sulfonate anions were found to be ligands in the complexes Tp*Zn-OSO2R. Spectroscopic evidence for perchlorate coordination in Tp*ZnClO4 · 2 DMSO conflicts with crystallograpic evidence against it in Tp*ZnClO4 · pyridine. The crystal structures of [(BIMA)Zn-OH2](CH3SO3)2, TpCum,MeZn-OS02CH3, TPtBu,MeZn-OSO2C6H4-p-CH3, and [TpCum,MeZn · NC5H5]ClO4 were determined.
    Additional Material: 4 Ill.
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  • 96
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 295-298 
    ISSN: 0009-2940
    Keywords: Rhenium ; Oxides ; Alkyl ligands ; Dirhenium compounds ; Metal-metal interactions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Most alkylrhenium(VII) oxides, e.g. ((cyclo)-C3H5)Re03 (2) are rather sensitive to temperature and moisture with the prominent exception of methyltrioxorhenium (1). The corresponding alkylrhenium(VI) oxides of formula [RR′(O)- Re(μ-O)]2 [R=R′=(cyclo)-C3H5 (3), iPr (4); R=CH3, R′=C2H5 (5), R=CH3, R′=iPr (6)] are much more stable in this regard. They can be handled in air at room temperature. They were synthesized from Re207 and dialkylzinc precursors, fully characterized and are available in much higher yields than their ReVII congeners. Mixed tetraalkyltetraoxodirhenium(VI) complexes (R # R′) synthesized from 1 and dialkylzinc compounds form as a mixture of cis/trans isomers. They are oily liquids at room temperature. The Re=O and Re-Re stretching force constants as a measure of the bond strengths, were determined from IR and Raman data.
    Additional Material: 3 Tab.
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  • 97
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 335-340 
    ISSN: 0009-2940
    Keywords: Allylsilanes ; Superbases ; Metalations ; Stereoselectivity ; Cyclizations ; Silicon ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When treated with two equivalents of a butyllithium/potassium tert-butoxide mixture, terminal olefins carrying unprotected hydroxy or carboxy groups generate allylmetal intermediates which can be trapped with chlorotrimethylsilane to afford functionalized (Z)-2-alkenyltrimethylsilanes. One equivalent of the superbasic reagent suffices if the unsaturated alcohols are first protected as acetals before being subjected to the metalation/silylation/hydrolysis sequence.
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  • 98
    ISSN: 0009-2940
    Keywords: Metallacycloalkanes ; Metallacycloalkenes ; Osmium ; Iron ; Cyclic ketones ; Metallacycles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the bis(triflates) [F3CSO3-(CH)m-O3SCF3] [m = 5-10, 12, 14, 16 (1a-i) with Na2[Os(CO)4] in dimethyl either affords the osmacycloalkanes 2a, 2b and 2f-i (m = 5, 6, 10, 12, 14, 16), diosmacycloalkanes 3a-i (m = 5-10, 12, 14, 16), and triosmacycloalkanes 4a-i (m = 5-10, 12, 14, 16). The structure of 3f was investigated by an X-ray structural analysis. This 22-membered disomacycle crystallizes in the space group Pā with Z = 1. If the unsaturated cis-4-octen-1,8-diyl bis(trifluoromethanesulfonate) (5) is treated with Na2[Os(CO)4] the diosmacyclooctadeca-5,14-diene 6 is obtained. By treating the bis(triflates) 1a, b with Na2[Fe(CO)4] the corresponding ferracycloalkanes are formed only in situ. Insertion of carbon monoxide into the M-C σ bonds leads to the cyclic ketones 7a, d and to the diketone 8d.
    Additional Material: 4 Ill.
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  • 99
    ISSN: 0009-2940
    Keywords: Pyrrolidinephosphanes ; 3-Hydroxypyrrolidine ; 3-Diphenylphosphanylpyronlidine ; Salt effects ; Polymorphism ; Homogeneous catalysis ; Palladium ; Asymmetric catalysis ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of both enantiomers of 3-diphenylphosphanulpyrrolidiine (2) and several N-substituted derivatives together with two PdIi complexes of this ligand is reported. Form L-malic acid and L-hydroxyproline both enantiomers of 3-hydroxypyrrolidine are prepared without any problems due to epimerization. KPPh2 in the presence of LiCl is shown to be the most effective reagent for the synthesis of 2. The reported X-ray structure determination sof Pdl2 complexes show a rather rigid bicyclic hetero-norbornane skeleton. The flexibility of the other parts of the molecules is obvious in several polymorphs revealed by this method. This polymorphism is additionally investigated by a 31P-CP-MAS study. From solution 1-, 13C- and 31P-NMR studies it is concluded that the bicyclic hetero-norbornane skeleton is retained in solution.
    Additional Material: 3 Ill.
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  • 100
    ISSN: 0009-2940
    Keywords: Trichlorosilylation ; Dichlorophosphanes ; Silylphosphanes ; Amino(silyl)phosphanes ; Silicon /Reductions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of hexachlorodisilane and of trichlorosilane/triethylamine with alkyl-and dialkylaminodichlorophosphanes RPCl2 1a-i [R = iPr: a; (Me3Si)2CH: b; R=1-adamantly: c: R=tBu: d; R=Et2N: e; R=iPr2M: f] furnish bis(trichlorosilyl)-phosphanes RP(SiCl3)2 3a-f. However, when less bulky substituents are attached to the phosphorus atom, so that there is little steric crowding, the double reductive silylations leading from 1 to 3 are accompanied by side reactions and decomposition of 3. Therefore, only 3b, 3c, 3d, and 3f wre isolated in a pure state. These compounds are more readily prepared by the; trichlorosilane/triethylamine method. 1H-, 31P- and 29Si-Nmr spectra confirm their constitution. The structure of solid 3f, the first aminobis(trichlorosilyl)phosphane, was determined by X-ray crystallography. 3f contains a phosphorus atom in a pyramidal environment surrounded by two silicon atoms and a planar nitrogen atom of the diisopropylamino group.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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