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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 739-743 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ohmic contacts produced by high-energy pulsed laser beam alloying Au/Te/Au/n-GaAs are investigated by micro Raman spectroscopy. The results are compared to those from furnace annealed ohmic contacts. For the furnace as well as for the laser annealed ohmic contacts, no evidence for a doping of the contact region is found in the Raman spectra. The presence of a highly disordered GaAs surface layer is observed for both types of contacts. In addition, after furnace processing a Ga2Te3 layer is formed. These results are consistent with earlier Mössbauer studies. For the laser alloyed samples the results strengthen the role of a defective/disordered interface structure where conduction might occur by a resonant tunneling process involving localized gap states.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 598-600 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Polycrystalline silicon gate metal-oxide-semiconductor transistors, fabricated with polycrystalline silicon leads, were repeatedly electrically stressed by constant-current Fowler–Nordheim tunneling cycles. After every stress cycle the devices were annealed for various time intervals at 950 °C. Capacitance-voltage measurements were used to detect stress-related interface-state generation rates and saturation values. It was found that although the stress-generated interface states are totally annealed by the thermal treatment, their generation rates and saturation values after anneal are a strong function of the anneal time, significantly exceeding the values of the fresh devices and inversely dependent on the anneal time. From the results it is concluded that a new type of latent interface-state sites is generated by the combination of tunneling stress and high-temperature annealing.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 116 (1994), S. 2235-2242 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 186-188 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Polycrystalline silicon (poly) gate metal-oxide-semiconductor (MOS) transistors were electrically stressed by constant-current tunneling. After the stress the devices were thermally annealed for variable times in the temperature range between 800 and 950 °C, and a second tunneling stress was performed. Capacitance-voltage (C-V) curve broadening and a charge pumping (CP) technique were used to detect interface state generation. It was found that the stress generated interface states are totally annealed by the thermal treatment. On the other hand, generation rates and saturation values, due to the second stress after annealing, exceed those of the fresh devices. Analysis of the generation process indicates that two types of interface states are generated: one, similar in its generation rate and saturation value to that of a fresh device, and another one, which is characterized by a higher generation rate and saturation value, is attributed to a new type of latent site. The density of this new type of latent interface states site decays exponentially with the annealing time. The annealing rate follows a temperature-dependent Arrhenius function. The anneal of this new type of interface state is characterized by an activation energy of 3.47 eV.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Clinical and experimental dermatology 18 (1993), S. 0 
    ISSN: 1365-2230
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Cutaneous melanoma may occur as isolated, so-called 'sporadic’cases or in association with multiple atypical naevi and in familial clusters, in which case it is referred to as the familial dysplastic naevus syndrome (DNS).In this retrospective study (a) the number and body distribution of naevocytic naevi and (b) the body distribution of malignant melanoma (MM) in individuals with familial DNS were compared in order to study their association. In 45 patients with familial DNS aged 20–39 years naevus counts on trunk and lower extremities were compared with melanoma data and distributions from a second group of 43 patients from the same DNS families aged 12–66 years.Men had significantly more naevi of a size 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:03076938:CED248:ges" location="ges.gif"/〉 2 mm or 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:03076938:CED248:ges" location="ges.gif"/〉5 mm on the back than women (P=0.02). Women showed a tendency towards a greater number of naevi on the lower extremities than men, but in women no significant difference in naevi between the lower extremities and the back was found. The total number of naevi on the trunk and lower extremities in familial DNS patients was higher than that in the general population.In conclusion, it was found that predilection sites for melanoma in familial DNS patients of both sexes correspond with the distribution of naevi; in males naevi and melanoma counts and percentage distributions were higher on the back, in females both the back and the lower extremities were affected.These findings strongly suggest an association between naevus distribution and melanoma occurrence and sire in familial DNS, analogous to earlier reports on sporadic melanoma.1,2
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Three Cambridge Center, Suite 208, Cambridge, MA 02142, USA : Blackwell Scientific Publications Inc.
    International journal of gynecological cancer 1 (1991), S. 0 
    ISSN: 1525-1438
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have evaluated aspects of the EGF receptor content of four human cell lines derived from patients with previously untreated carcinoma of the cervix. Scatchard analysis revealed that three of the lines possessed approximately 2×105 low-affinity and 2×104 high-affinity receptors, whereas the fourth line had approximately 9×104 low-affinity receptors and 9×103 high-affinity receptors. Immunocytochemical staining using the monoclonal antibody EGFR1 showed wide intra- and inter-line variation in staining intensity. Flow cytometric analysis of EGFR1 demonstrated a fivefold difference in staining intensity between lines. Thirteen cloned derivatives of one of the lines exhibited a 200% variation in EGFR1 staining intensity. There were no differences in radiosensitivity in four of the cloned lines with different EGF receptor levels. Southern blotting analysis did not reveal any rearrangement or amplication of the EGF receptor gene. These three different methods for determining receptor content produced variations in the ranking of receptor number across the four cell lines. These studies with cervix carcinoma cell lines demonstrate the presence of varied levels of EGF receptors according to the methodology used. This may reflect differences in biological characteristics of the cell lines evaluated.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Chromotropic acid and acerylacetone methods for qualitative determination of formaldehyde were tested in parallel on 4N commercial samples, with high-performance liquid chromotography (HPLC) implemented for quantitave measuce. In addition, interference with the detection of formaldehyde was investigated by analyzing 12 other aldehydes and ketories, 7 essential oils and 3 polysorbstes. Throughout this comparative-study. the disadvantages of the chromotropic acid method., of with 2 variants were used, were delineated and we found that the acetylacetone test proved to be a more efficient screening method for formaldehyde detection in a clinical laboratory.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta diabetologica 30 (1993), S. 105-107 
    ISSN: 1432-5233
    Keywords: Leucocytes ; Nephropathy ; Smoking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case-control study was carried out to analyse leucocyte counts in relation to proteinuria and smoking in type 1 (insulin-dependent) diabetes. The subjects were 180 smoking (87 women, age 32±11 years, diabetes duration 14±6 years) and 188 nonsmoking (88 women, age 32±11 years, diabetes duration, 14±6 years) type 1 diabetic patients. Leucocyte counts were higher in smokers than in nonsmokers, both in women (7.6±2.3 vs 6.8±1.9×109/l,P〈0.01) and in men (8.1±2.7 vs 6.4±2.0×109/l,P〈0.0001). Leucocyte counts correlated with the number of cigarettes smoked per day (r=0.32,P〈0.0001), but were unrelated to glycosylated haemoglobin levels. Among nonsmokers, leucocyte counts were comparable between patients with normal proteinuria (6.7±2.2×109/l,n=106), microproteinuria (6.3±1.7×109/l,n=66) and macroproteinuria (6.8±1.1×109/l,n=16). Among smokers, patients with macroproteinuria or microproteinuria had higher leucocyte counts than those with normal proteinuria [8.9±3.0×109/l, (n=36) vs 8.4±2.7×109/l (n=61) vs 7.0±1.9×109/l (n=83)P〈0.0001], a finding which was not due to differences in the number of cigarettes smoked per day. It is concluded that in these type 1 diabetic patients leucocyte counts were higher in smokers than in nonsmokers. Among non-smokers leucocyte counts were comparable between patients with normal proteinuria and increased proteinuria, whereas among smokers leucocyte counts were higher in patients with increased proteinuria. It appears it would be worthwhile examining in prospective studies whether leucocyte counts can contribute to identifying those type 1 diabetic patients with a particularly high risk of cardiovascular complications.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Peu après l'introduction de la lithotritie par ondes de choc extracorporelles (LOCE) comme modalité thérapeutique nouvelle dans la lithiase biliaire, nous avons commencé une étude randomisée pour évaluer le coûts de la LOCE comparée à la cholécystectomie traditionnelle, le “gold standard”. Pendant cette étude s'étalant sur une période de trois ans, il n'a été possible, cependant, d'inclure que 8.3% seulement (37/488) des patients éventuellement éligibles. Trois facteurs pouvant empêcher le recrutement ont pu être identifiés. Premièrement, un nombre limité de patients éligibles pour la LOCE (et donc pour l'étude), fait imprévisible selon les données de la littérature, deuxièmement, l'introduction de la cholécystectomie par coelioscopie et son retentissement sur l'aspect thérapeutique de la lithiase, et troisièmement, la préférence du patient, refusant la randomisation dans un bon nombre de cas. On conclue qu'il n'est pas toujours aussi facile de conduire une étude randomisée en chirurgie, en raison des circonstances imprévues. Entrer des patients dans un essai est très difficile dans des domaines qui évoluent vite, tel que le traitement de la lithiase biliaire. Obtenir le consentement éclairé est également difficile lorsque les modalités thérapeutiques sont très divergentes. Il est probable que la réalisation d'une étude randomisée et contrôlée sur les effects de la cholécystectomie coelioscopique ne verra jamais le jour.
    Abstract: Resumen Al poco tiempo de la introducción de la litotricia extracorpórea (LEC) como un promisoria y novel modalidad terapéutica para la enfermedad litiásica biliar, se realizó un estudio randomizado para evaluar la efectividad en cuanto a costo en comparación con la colecistectomía abierta, que es el “patrón oro”. Se encontró que en los 3 años del período de ingreso de pacientes al estudio, sólo 8.3% (36=7/448) de los pacientes pudieron ser ingresados, habiéndose identificado tres que interfirieron con el reclutamiento. Primero, la restringida elegibilidad para LEC (y por consiguiente para el estudio), lo cual no era predecible con base en la información de la literatura. Segundo, la introducción de la colecistectomía laparoscópica. Tercero, una fuerte preferencia por parte del paciente, lo cual inhibía la randomización. Ninguno de estos mecanismos podía ser prevìsto durante la fase de diseño del estudio. La conclusión es que no siempre es factible conducir estudios randomizados en el campo de la cirugía, debido a circunstancias imprevistas. Ingresar pacientes a ensayos clínicos en cirugía es difícil cuando se trata de campos de rápida evolución, como lo es del manejo de la colelitiasis. También es difícil lograr el consentimiento informado cuando las características de las formas de tratamiento son muy divergentes. Es por ello, que posiblemente nunca se hará un estudio randomizado sobre los efectos de la colecistectomía laparoscópica.
    Notes: Abstract Shortly after extracorporeal shock wave lithotripsy (ESWL) was introduced as a promising new treatment modality for gallstone disease, a randomized controlled study was performed to assess the cost-effectiveness of ESWL compared to open cholecystectomy, the gold standard. During the performance of this study it was found that during a 3-year intake period only 8.3% (37 of 448) of the patients could be entered into the trial. Three factors were identified that hampered patient accrual: (1) restricted eligibility for ESWL (and thus for the study), which could not have been predicted on the data provided in the literature; (2) the introduction of laparoscopic cholecystectomy; and (3) strong patient preference, inhibiting randomization. All three mechanisms could not have been predicted during the design phase of the study. It is concluded that it is not always feasible to conduct a randomized study in surgery due to unforeseen circumstances. Entering patients into surgical trials is difficult in quickly evolving fields of surgery, such as the management of gallstone disease. Acquiring informed consent is also difficult when treatment characteristics are divergent. A randomized controlled study on the effects of laparoscopic cholecystectomy will therefore probably nerver be performed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 344 (1991), S. 213-219 
    ISSN: 1432-1912
    Keywords: Ethylcholine aziridinium (AF64A) ; Choline acetyltransferase ; Hippocampus ; L-glutamate ; NMDA receptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The reaction of the glutamatergic systems in the rat hippocampus to the withdrawal of cholinergic function after cholinergic degeneration induced by ethylcholine aziridinium (AF64A) was investigated. Furthermore, the question whether blockade of N-methyl-D-aspartate (NMDA) receptors by MK-801 has an impact on the extent of the cholinergic lesion was addressed. After bilateral intracerebroventricular injection of AF64A (2 nmol/ventricle) the activity of choline acetyltransferase (ChAT) started to decline in the hippocampus within 24h. The reduction of ChAT activity reached its maximum within 4 days (65%) and persisted during the observation period of 65 days. The loss of ChAT activity was accompanied by a transient decline in the level of glutamate, which was most pronounced 1 to 2 days after AF64A (25% reduction). Within 65 days the glutamate level returned to normal. A detailed subdissection of the Hppocampus revealed that the cholinergic system was most affected in the ventral part of the hippocampus and the CA 3 subfield. On the other hand, the transient reduction in glutamate was restricted to the CA 1 and CA 3 area. In the dentate gyrus the marked loss of cholinergic function was not accompanied by any reduction in glutamate level. Treatment of the AF64A-injected rats with the muscarinic agonist pilocarpine prevented the decline in glutamate levels. The transient nature of the decline in glutamate as well as its reversal by treatment with pilocarpine are suggestive of an increased release of glutamate in response to the withdrawal of cholinergic function. Since treatment with the NMDA antagonist MK-801 during the acute phase of degeneration did not attenuate the extent of the cholinergic lesion, it is concluded that glutamate does not contribute to the neurotoxicity of AF64A.
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