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  • 1
    Electronic Resource
    Electronic Resource
    Heavy doping effects in the diffusion of group IV and V impurities in silicon (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 691-698 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Studies of the diffusion of Ge, Sn, As, and Sb in Si at high donor concentrations provided by phosphorous doping have been performed. It is found that for donor concentrations, CD below ∼2×1020 cm−3, the diffusivity depends linearly on CD; for doping concentrations above ∼2×1020 cm−3, however, the diffusivity increases dramatically with increasing donor concentrations. This behavior has been successfully modeled within the vacancy–percolation model, and it is concluded that collective phenomena play a significant role at high donor concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.353324
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  • 2
    Electronic Resource
    Electronic Resource
    Identification of Immunodominant Antigens during Infection with Mycobacterium tuberculosis (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 36 (1992), S. 0 
    Details
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: T lymphocytes isolated from mice infected with Mycobacterium tuberculosis respond vigorously to proteins secreted by the bacilli and these antigens may be of importance in the generation of protective immunity against the disease. In this study, short-term culture filtrate (ST-CF), which constitutes a complex mixture of secreted proteins, was fractionated by a modified preparative SDS-PAGE technique. The ability of each fraction to be recognized by T cells isolated from infected mice was evaluated by quantifying proliferation and IFN-γ production in cell cultures. Two molecular mass regions 4–11 and 26–35 kDa were found to possess marked stimulatory properties. Four potent single antigens were mapped within the stimulatory regions. These purified antigens stimulated T cells isolated from mice at the height of a tuberculous infection to produce large amounts of IFN-γ, Two of these stimulatory antigens belonged to lhe antigen 85 complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3083.1992.tb03144.x
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  • 3
    Electronic Resource
    Electronic Resource
    Ultralow power low noise ultrahigh frequency magnetic resonance spectrometer (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 157-162 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We describe a simple marginal oscillator that operates at ultralow power dissipation (≥20 μW at 750 MHz) for use in ultrasensitive low noise magnetic resonance detection at very low temperatures. We have operated the circuit down to 0.6 K with the sample maintained below 20 mK and in magnetic fields up to 4.0 T. The samples are maintained at mK temperatures by physically separating the sample from the rf coil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142980
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  • 4
    Electronic Resource
    Electronic Resource
    Failure to Induce Long-term Depression by an Anti-Correlation Procedure in Area CA1 of the Rat Hippocampal Slice (1993)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 5 (1993), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have independently in our two laboratories re-examined the report by Stanton and Sejnowski (Nature, 339, 215 – 218, 1989) that single stimuli to a test pathway in area CA1 of the hippocampal slice, when delivered between short bursts of stimuli to a second, convergent pathway, produce an associative long-term depression (LTD) in the test pathway. While robust associative LTP was observed when stimuli to the two inputs were correlated in time, the anti-correlation procedure failed to induce LTD; rather, a trend towards potentiation was observed. This result was obtained using both submerged and interface chambers, and in two different strains of rat. A transient depression lasting for a few minutes could usually be elicited by strong tetanic stimulation; this depression was not restricted to activated pathways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1993.tb00909.x
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  • 5
    Electronic Resource
    Electronic Resource
    The cutaneous corticosteroid vasoconstriction assay: a reflectance spectroscopic and laser-Doppler flowmetric study (1993)
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 128 (1993), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Cutaneous vasoconstriction induced by topical corticosteroids was investigated using non-invasive bioengineering techniques. Corticosteroids of different potency in alcoholic solution were applied topically, under occlusion, and cutaneous blanching was investigated using visual scoring, reflectance spectroscopy (RS) and laser-DoppIer flowmetry (LDF), The RS technique allowed separation of cutaneous haemoglobin content into arterial oxygenated (OH) and venous deoxygen-ated haemoglobin (DOH) components.Application of alcohol decreased total haemoglobin by 10%, with a corresponding 8% increase in blood flow (BF). Clobetasol propionate was the most potent vasoconstrictor, inducing signiflcant visible blanching and decreasing DOH (30%), OH (33%) and BF (18%) (P〈0.01). Fluocinolone acetonide, betamethasone-17-valerate and dexamethasone also caused visible blanching (P〈0.01). There was no signiflcant decrease in BF, but reflectance spectroscopy showed a decrease in DOH (P〈0.01). Tixocortol, CMJ and hydrocortisone acetate did not produce signiflcant blanching, although DOH was decreased compared with the alcohol control.Measured by reflectance spectroscopy, corticosteroid-induced blanching was predominantly venoconstriction and only the most potent corticosteroid caused a significant decrease in OH and blood flow. This may explain why previous attempts to improve cutaneous vasoconstriction assays using laser-Doppler flowmetry have been unsuccessful.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2133.1993.tb00262.x
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  • 6
    Electronic Resource
    Electronic Resource
    Faecal enzymes: in vivo human skin irritation (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Contact dermatitis 30 (1994), S. 0 
    Details
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Digestive enzymes in faeces have been reported to posses skin irritation potential. The present study was designed to investigate the in vivo irritant potentials of faecal concentrations of proteolytic and lipolytic digestive enzymes in bile salt mixtures. In a 21-day cumulative irritation assay, clinical evaluation and noninvasive bioengineering techniques were used. 5 days occlusive exposure to phosphate buffer (pH = 8) caused no visual skin damage but reflectance spectroscopy demonstrated significant vasodilation (p 〈 0.01) and increases in transepidermal water loss (TEWL) and skin pH were also observed (p 〈 0.01). These increases were still present at days 12 and 19. Occlusive exposure to physiologic concentrations of faecal enzymes resulted in significant visual and objective scores at day 5, 12, and 19, with increased readings as a function of exposure time (p 〈 0.01). The enzyme mixture containing lipase caused delayed onset of skin erythema and epidermal barrier disruption compared to elastase and chymotrypsin containing solutions. Prolonged occlusive exposure to digestive enzymes in faecal concentrations caused severe skin erythema and epidermal barrier disruption in a human model, suggesting a possible etiologic role of digestive enzymes in perianal, circumstomal or diaper dermatitis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0536.1994.tb00696.x
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  • 7
    Electronic Resource
    Electronic Resource
    Erythema induced by organic solvents: in vivo evaluation of oxygenized and deoxygenized haemoglobin by reflectance spectroscopy (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Contact dermatitis 27 (1992), S. 0 
    Details
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objective: (i) using a new non-invasive technique capable of evaluating quantitatively and qualitatively the haemoglobin content of the skin (ii) to evaluate delipidization induced by organic solvents. Patients: 11 Caucasians treated for 1 min in a randomized manner on the volar forearm with a mixture of chloroform/methanol (2: 1) (CM) and ether/acetone (1:1) (EA) to delipidize the skin. Method erythema was evaluated by computerized remittance spectroscopy immediately after delipidization and hourly for 2 h. Results: only CM application induced subjectively observed and objectively quantified erythema. Erythema was related to a significant increase in oxygenized haemoglobin content due to dilatation of arterioles in the subpapillary plexus (P〈0.01). The increased blood flow induced a significant (P〈0.01) reduction in de-oxygenized haemoglobin in venous vessels immediately after CM application. Conclusion: short contact with certain potent solvent mixtures causes erythema, possibly due to massive lipid extraction and damage of the skin barrier. Using computerized remittance spectroscopy the visible erythema was composed of an increase in oxygenized haemoglobin and a relative decrease in deoxygenized haemoglobin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0536.1992.tb05190.x
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  • 8
    Electronic Resource
    Electronic Resource
    Chemical and pharmacologic skin irritation in man (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Contact dermatitis 25 (1991), S. 0 
    Details
    ISSN: 1600-0536
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Attention is increasingly being focused on the relationship of dissocial Ion constant (pKa) of chemicals and skin irritation presumably caused by pH effects at epidermal levels. Human skin Studies of irritation have utilized both subjective visual-palpation scores and reflectance spectroscopy (RS) or laser Doppler velocimetry (LDV) respectively. Several studies document that erythema determined subjectively and objectively correlates with the degree of skin irritancy, but others report lack of correlation between LDV and irritancy scored subjectively. In this study, pharmacologicol and chemical in vivo, skin irritation was evaluated utilizing an improved reflectance spectrophotometer equipped with computerized data analysis. In 16 white females, a model for skin irritation was induced by a 24-h patch application of 4 basic chemicals, imipramine, norephedrine, nicotine and 8-aminoquinoline, with pKa's ranging from 3.8 to 9.5. Skin pigmentation (melanin) and the relative amounts of oxygenized (arterial) and deoxygenized (venous) hemoglobin present in the erythematous skin were calculated. A clear increase in the hemoglobin content was observed in chemical and vehicle exposed sites. Although skin irritation is a complex phenomenon involving chemical and solution properties, percutaneous absorption and the biological drug response, high pKa (p 〉 0.01) was predictive of acute skin irritation in man using computerized analysis of reflectance spectroscopy, A high correlation between visual score and RS was found (r= 0.91).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0536.1991.tb01875.x
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  • 9
    Electronic Resource
    Electronic Resource
    Diurnal variations of amino acids and organic acids in xylem fluid from Lagerstroemia indica: an endogenous circadian rhythm (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 89 (1993), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Diurnal variations in the concentrations of major organic compounds occurred in xylem fluid extracted from Lagerstroemia indica L. The concentration of amino acids and the N/C ratio was at a maximum and that of organic acids was at a minimum between 1230 and 2030 h. Since the concentrations of total organic nitrogen, total amino acids and most individual amino acids (but not organic acids or sugars) were also proportional to xylem tension two experiments were performed to discern whether variations in chemistry were a consequence of diurnal changes in moisture stress. In the first experiment, L. indica, exposed to variable levels of moisture stress during midday, manifested an increase in organic acids and a reduction in the N/C ratio. In the second experiment, chemical profiles of xylem fluid were collected and compared for plants exposed to a natural photoperiod, constant darkness or continuous light at noon and midnight. After 1 day amino acids increased in concentration during midday for all treatments; the variation was greatest (10-fold) for plants in constant darkness where xylem tension varied from 0.20 to 0.25 MPa. Only plants exposed to continuous light lost a diurnal rhythm after 3 days. Thus, the circadian rhythm was endogenous, terminated in continuous light and was not mediated by changes in moisture stress. Glutamine accounted for most of the diurnal variation in total amino acids, organic nitrogen and the N/C ratio in xylem fluid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1993.tb05285.x
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of glipizide on glucose metabolism and muscle content of the insulin-regulatable glucose transporter (GLUT 4) and glycogen synthase activity during hyperglycaemia in type 2 diabetic patients (1994)
    Springer
    Acta diabetologica 31 (1994), S. 31-36 
    Details
    ISSN: 1432-5233
    Keywords: Glipizide ; Type 2 diabetes mellitus ; Glucose metabolism ; GLUT 4 ; Glycogen synthase activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To examine whether sulphonylureas influence hyperglycaemia-induced glucose disposal and suppression of hepatic glucose production (HGP) in type 2 diabetes mellitus, a 150-min hyperglycaemic (plasma glucose 14 mmol/l) clamp with concomitant somatostatin infusion was used in eight type 2 diabetic patients before and after 6 weeks of glipizide (GZ) therapy. During the clamp a small replacement dose of insulin was given (0.15 mU/kg per min). Isotopically determined glucose-induced glucose uptake was similar before and after GZ administration which led to improved glycaemic control (basal plasma glucose 12.2±1.3 vs 8.9±0.7 mmol/l;P〈0.01). Glucose-induced suppression of HGP was, however, more pronounced during GZ treatment (0.96±0.14 vs 1.44±0.20 mg/kg per min;P〈0.02). Following GZ treatment hyperglycaemia failed to stimulate glycogen synthase activity. Moreover, GZ resulted in a significant increase in the immunoreactive abundance of the insulin-regulatable glucose transport protein (GLUT 4) (P〈0.02). In conclusion, these results suggest that GZ therapy in type 2 diabetic patients enhances hepatic sensitivity to hyperglycaemia, while glucose-induced glucose uptake remains unaffected. In addition, GZ tends to normalize the activity of glycogen synthase and increases the content of GLUT 4 protein in skeletal muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00580757
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