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  • 1990-1994  (13)
  • 1915-1919
  • 1870-1879
  • 1994  (13)
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 4511-4515 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An experiment was performed in order to determine whether a first-order or second-order mechanism governs the re-emission of deuterium molecules from graphite during D+ bombardment. The order of the release mechanism should be reflected in the dependence of the re-emission on the incident flux density. No flux density dependence was observed, indicating a first-order process, in agreement with a hydrogen transport model where the rate of molecule release is determined by a first-order process involving H diffusion within graphite crystallites.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 3476-3478 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using high-resolution transmission electron microscopy (HRTEM), we have studied InAs/GaSb superlattices grown by molecular beam epitaxy. Our HRTEM observations indicate that the apparent interface width is on the order of 1 monolayer for InSb-like interfaces, and on the order of 2 monolayers for GaAs-like interfaces. The combination of these results with x-ray diffraction and Raman scattering measurements leads us to conclude that these interface widths are principally due to roughness rather than to interfacial diffusion.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 32 (1994), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: Measurements of air-permeability in outcrops provide a means of obtaining numerous spatially distributed measurements for statistical analysis and subsequent parameterization of ground-water flow and transport modeling. The air-minipermeameters previously used for such studies generally consist of a compressed air source, rotameters, and diaphragm gauges. We present a lightweight syringe-based air-minipermeameter (LSAMP) design that is significantly more portable than previous instruments. The prototype model is contained in a 12.7 × 15.2 × 23 centimeter (5 × 6 × 9 inch) electrical box and weighs approximately 2 kilograms. The prototype LSAMP has a sampling range of 0.5 to 200 darcys. Individual measurements in this range require less than one minute. Permeability measured with the LSAMP closely correspond to permeability measured with a traditional minipermeameter and those measured on cores. Measurement error caused by soil moisture is less than 5 percent for volumetric water contents less than 5 percent. An analysis of variance on 38 triplicate measurements indicates that the variability associated with measurement error is much less than the range of measured values. Repeated permeability measurements under field conditions on two standard cores indicate that while the measurement error is greater under field conditions, the prototype device field performance is consistent with laboratory calibration results.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Contact dermatitis 30 (1994), S. 0 
    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
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  • 5
    ISSN: 1432-1920
    Keywords: HMPAO-SPECT ; Computer-assisted mapping program ; Alzheimer's disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A computer-assisted mapping program was developed to determine changes of cerebral perfusion in normal and pathological aging using single photon emission computer tomography (SPECT) and99mTc-hexamethylpropyleneamine oxime (HMPAO). The software program outlined the cortex on 14 adjacent brain slices, and superimposed a ring of 12 regions of interest on each slice. Regional/global and regional/cerebellar relative flow values were calculated in 27 patients with clinically diagnosed Alzheimer's disease (AD) (mean age 71 years, SD 7.6) and in 10 normal controls (mean age 73.7 years, SD 7.3). The Dementia Rating Scale (DRS) was used to assess mental status in all subjects. Multiple regression analysis demonstrated a significant correlation between relative flow values and the DRS score. Regional/cerebellar (R=0.88,p〈0.0001) relative flow values were a better indicator of cortical impairment than regional/global relative flow values (R=0.68,p=0.003). Of the brain regions of interest, the left parietal flow values correlated best with the DRS score (r=0.83,p〈0.0001), a cutoff value of 77 accurately classifing 80% of the normals and 100% of the patients diagnosed as having Alzheimer's disease. The data show that computer-assisted mapping of SPECT can provide semiquantitative flow values with high diagnostic accuracy.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 208-216 
    ISSN: 1600-5740
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 55 (1994), S. 249-252 
    ISSN: 1432-0827
    Keywords: Bone mass ; Ethnicities ; Hawaiian ; Filipino ; Japanese ; White
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Our study compares the bone mass of Hawaiian, Filipino, Japanese, and white women living in Oahu, Hawaii. Eligible women ranged in age from 25 to 34; all had bone mass measurements at the spine, calcaneus, and proximal and distal radius. Their average bone mineral density (BMD) remained stable with age at all four bone sites, indicating that the age range 25–34 may represent the peak bone mass. Bone mass varied, however, between ethnicities; differences in BMD up to 11% were observed. The Hawaiian women had the greatest BMD, and whites had the second greatest BMD at the spine and calcaneus. The Japanese most frequently had the lowest BMD. Differences in body size partly explained the differences; most ethnic differences were reduced or eliminated after adjusting for height and weight. At the spine, the ethnic differences for BMD were also apparent with BMC and with vertebral area. Hawaiian and white women had greater values than Japanese or Filipino women. Differences at the proximal radius resembled the spine, except that whites had the widest proximal widths. The results were more complex for the distal radius. At the distal radius whites had the lowest BMD of the four ethic groups. The difference between whites and Hawaiians derived from the greater bone mineral content (BMC) of the Hawaiian women. By contrast, the difference between whites and the Japanese and Filipinos derived from the wider distal widths of the white women. Compared with the Japanese and Filipino women, the white women appeared to disperse their BMC at the distal radius across a wider bone width. Such differences in bone distributions might lead to an altered risk of distal radius (wrist) fractures. Within ethnicities there was marked variation among individuals in bone mass. At the extremes, women differed by 50–100% or more within all four ethnic groups.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 55 (1994), S. 243-248 
    ISSN: 1432-0827
    Keywords: Osteoporosis ; Bone density ; Longitudinal studies ; Statistical models ; Decision models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract We calculated how long to wait before repeating bone mineral density (BMD) measurements to reassess fracture risk. Correlation results from serial measurements of 495 postmenopausal Japanese-American women were used to estimate 95% confidence intervals (CI) for future BMD. After 7 years of follow-up, BMD correlations with the initial measurement ranged between 0.81 and 0.94, depending on age group and measurement site. In this analysis, the period between measurements was defined as the time required for the lower 95% CI to fall below the BMD value corresponding to doubling of fracture risk. Progressive bone loss causes fracture risk to double after 10 years, on average. However, the 95% CIs indicate that a second BMD measurement will detect risk doubling after only 2 or 3 years for some women. For untreated, early postmenopausal women, the period between measurements was approximately 2–5 years for the radius and 4–6 years for the calcaneus, depending on the initial BMD level. The period was approximately 1 year longer for women age 60 and older. Treatments that halve the bone loss rate would increase the period by 1–3 years. In the absence of a second measurement of BMD, the CI will continue to expand with time, corresponding to a wider range in risk between individuals, and a greater proportion of women will be at increased fracture risk. Obtaining a second BMD measurement pinpoints the patient's status within the precision of the measurement. We conclude that repeated BMD measurements will provide a more accurate estimate of fracture risk than a single, baseline measurement.
    Type of Medium: Electronic Resource
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  • 9
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    Gloucester : Periodicals Archive Online (PAO)
    Parliamentary history. 13:3 (1994) 372 
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 26 (1994), S. 132-133 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
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