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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
    Diffusion of ion-implanted Sn and Sb in heavily doped n-type silicon (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 755-757 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The diffusion of ion-implanted Sn and Sb in silicon single crystals during rapid thermal annealing at 1000 and 1050 °C has been studied as a function of P donor concentration. For extrinsic/intrinsic carrier concentration ratios (n/ni )≥20, almost identical, extremely large diffusion coefficients are found for both impurities. The diffusion coefficients exhibit approximately an (n/ni )4 dependence. The onset of this dependence is accompanied by the appearance of a new defect-complex type containing Sb or Sn, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99823
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  • 3
    Electronic Resource
    Electronic Resource
    Properties of sputtered superconducting films of Bi2Sr2CaCu2Ox made by low-temperature in situ growth (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 2135-2137 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Superconducting films of Bi2Sr2CaCu2Ox have been fabricated on single-crystal MgO substrates by a low-temperature in situ process. Using a substrate temperature Ts≈645 °C, metallic films with a superconducting onset of 90–100 K and an extrapolated Tc0=56 K have been obtained. X-ray diffraction shows the films to be c-axis oriented. Electron microscopy reveals that the films are not significantly smoother than films which were post-annealed at 865 °C, and that some segregation into nonsuperconducting phases had occurred. The exact mechanism by which crystallization and superconductivity occurs at such low temperatures is not yet known, but it can be speculated that the surface atoms are less constrained and thus have a smaller energy barrier to overcome in forming a crystal structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102347
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  • 4
    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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  • 5
    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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  • 6
    Electronic Resource
    Electronic Resource
    Occurrence of Aspergillus umbrosus Antibodies in Danish Farmers (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Allergy 41 (1986), S. 0 
    Details
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Antibodies to Aspergillus umbrosus were investigated in 181 Danish farmers, 137 farmers spouses and a control group of 104 male blood donors with no relation to farming. By enzyme-linked immunosorbent assay (ELISA) higher levels of IgG antibodies were found in farmers than in their spouses and in non-farming controls (P 〈 0.0001). By double immunodiffusion precipitating antibodies occurred in 11 farmers, in none of farmers' spouses and in one control subject. Farmers and farmers' spouses who were non-smokers had higher IgG antibody levels than smokers in the same groups (P 〈 0.04). Farmers more than 30 years of age had higher IgG antibody levels than younger farmers (P 〈 0.04). Farmers rearing cattle tended to have higher IgG antibody levels than farmers without cattle. No correlation between antibody levels and respiratory symptoms or lung function parameters (FEV1 or FVC) could be demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1398-9995.1986.tb00285.x
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  • 7
    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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  • 8
    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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  • 9
    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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  • 10
    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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