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  • 1995-1999  (11)
  • 1905-1909
  • 1870-1879
  • 1999  (11)
  • 1
    Digitale Medien
    Digitale Medien
    Arsenic for antimony exchange on GaSb, its impacts on surface morphology, and interface structure (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 329-337 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: We quantify the rates and total amounts of the arsenic for antimony exchange on both the Sb-terminated and Ga (or In)-terminated GaSb (001) surfaces using in situ real time line-of-sight mass spectrometry (LOS-MS) during molecular beam epitaxy. On the Sb-terminated GaSb (001) surface, an As for Sb exchange is observed to occur at all values of incident As2 flux considered. At high substrate temperature, three-dimensional (3D) nanometer-sized clusters from as a consequence of As/Sb exchange and lattice mismatch strain between GaAs and GaSb. The 3D clusters are found to have lateral dimensions of ∼10–30 nm and heights of 1–3 nm by atomic force microscopy (AFM). By contrast, at lower substrate temperatures a two-dimensional surface morphology is maintained, and AFM reveals an array of atomically flat terraces. On the surface terminated by one monolayer (ML) of Ga or In, there exists a critical As2 flux below which the As/Sb exchange is greatly diminished. The net amounts of Sb leaving the surface during one period of InAs/GaSb type-II superlattice growth are measured in real time by LOS-MS and estimated to be in the range of 0–0.4 ML for the various conditions used. By supplying only an As2 beam to a GaSb surface covered by InAs, the Sb riding over the InAs layer is replaced by arsenic and the total amount of such Sb is measured. The amount of Sb riding on the InAs can be as large as 0.8 ML for the first 1 ML of InAs and it gradually decreases to zero as the number of InAs monolayer increases. X-ray diffraction data show that all the InAs/GaSb superlattices coherently match with the GaSb substrate in the growth plane. The average lattice constant along the growth direction reduces with decreasing Sb mole fraction shown by the increased Sb desorption signal. Using the information on As/Sb exchange and Sb riding on the InAs surface, we predict an average lattice constant along the growth direction to be consistent with the measured one to within 2×10−4. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.370733
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  • 2
    Digitale Medien
    Digitale Medien
    The NaCl pressure standard (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 5801-5808 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A revised pressure scale for NaCl is proposed as an update for the 30-year-old work of Decker. An alternative approach to the analysis is utilized in conjunction with more recent data. The zero-Kelvin compression curve is parameterized using local basis functions (splines) and constrained by accurate pressure-volume-temperature data. Thermal pressures are estimated within a quasiharmonic framework using a volume-dependent Grüneisen parameter and the Debye thermal energy. In the pressure regime extending to 5 GPa uncertainties in pressure (based on measured volumes) are estimated to be less than 1%. Uncertainty increases to 1.5% at 10 GPa and 3% at 25 GPa. The largest contribution to systematic uncertainty at the highest pressures is the lack of knowledge of the volume dependence of the Grüneisen parameter. Misfit of other calculated thermodynamic properties with respect to data is relatively small. On the basis of the current analysis, pressures determined using the older Decker calibration are low. Along the 300 K isotherm, apparent errors in the Decker scale are as large as −3% (−0.3 GPa at 10 GPa, −0.47 GPa near 18 GPa, and −0.37 GPa at 25 GPa). At higher temperatures the apparent errors are smaller. At 1100 K and 20 GPa the error is −0.2 GPa. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.371596
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  • 3
    Digitale Medien
    Digitale Medien
    APPLICATIONS OF IMPULSIVE STIMULATED SCATTERING IN THE EARTH AND PLANETARY SCIENCES (1999)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physical Chemistry 50 (1999), S. 279-313 
    Details
    ISSN: 0066-426X
    Quelle: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Thema: Chemie und Pharmazie , Physik
    Notizen: Abstract The elastic, thermodynamic, and transport properties of crystals and fluids at high temperature and pressure play a central role in the earth and planetary sciences as well as in a variety of technologies. These properties also constitute a principal experimental constraint on the description of intermolecular interactions at short distances. Aspects of "impulsive stimulated scattering," when adapted to measurements in the diamond-anvil high-pressure cell, provide an approach to the determination of a subset of equilibrium and dynamic properties at high density.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1146/annurev.physchem.50.1.279
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  • 4
    Digitale Medien
    Digitale Medien
    A condition index for evaluating larval quality of Macrobrachium rosenbergii ( de Man 1879) (1999)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 30 (1999), S. 0 
    Details
    ISSN: 1365-2109
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2109.1999.00411.x
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  • 5
    Digitale Medien
    Digitale Medien
    Characterization of tobacco geminiviruses in the Old and New World (1999)
    Springer
    Archives of virology 144 (1999), S. 703-717 
    Details
    ISSN: 1432-8798
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary.  Biological differences and molecular variability between six phenotypically distinct tobacco-infecting geminivirus isolates from southern Africa (Zimbabwe) and Mexico were investigated. Host range studies conducted with tobacco virus isolates ZIM H from Zimbabwe and MEX 15 and MEX 32 from Mexico indicated all had narrow host ranges restricted to the Solanaceae. Alignment of coat protein gene (CP) and common region (CR) sequences obtained by PCR, and phylogenetic analysis of the CP sequences indicated Zimbabwean isolates were distantly related to those from Mexico and that geographically proximal isolates shared their closest affinities with Old and New World geminiviruses, respectively. Zimbabwean isolates formed a distinct cluster of closely related variants (〉98% sequence identity) of the same species, while MEX 15 segregated independently from MEX 32, the former constituting a distinct species among New World geminiviruses, and the latter being a variant, Texas pepper virus-Chiapas isolate (TPV-CPS) with 95% sequence identity to TPV-TAM. Results collectively indicated a geographic basis for phylogenetic relationships rather than a specific affiliation with tobacco as a natural host. MEX 15 is provisionally described as a new begomovirus, tobacco apical stunt virus, TbASV, whose closest CP relative is cabbage leaf curl virus, and ZIM isolates are provisionally designated as tobacco leaf curl virus, TbLCV-ZIM, a new Eastern Hemisphere begomovirus, which has as its closest relative, chayote mosaic virus from Nigeria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s007050050537
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  • 6
    Digitale Medien
    Digitale Medien
    Risedronate, a Highly Effective, Short-Term Oral Treatment for Paget's Disease: A Dose-Response Study (1999)
    Springer
    Calcified tissue international 64 (1999), S. 93-99 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Key words: Risedronate — Bisphosphonate — Paget's disease.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Abstract. Risedronate is a potent pyridinyl bisphosphonate being developed for bone diseases such as Paget's disease and osteoporosis. In this study, we compared the efficacy, safety, and tolerability of three different doses of oral risedronate in 62 patients with severe Paget's disease of bone [serum alkaline phosphatase (AP) 〉3 times the upper limit of normal]. Patients were treated at six study centers with either 10, 20, or 30 mg oral risedronate daily for 28 days and followed up to day 85. The primary efficacy parameter was percentage change from baseline in AP excess. The data show that there is a dose-response with risedronate: patients who received 30 mg oral risedronate for 28 days benefited most, with a mean percentage decrease in AP excess of 72.2% (20 mg: 57.9%; 10 mg: 48.0%). Time to response—the first time point when there was a ≥30% reduction from baseline in AP excess and ≥50% reduction from baseline in urinary hydroxyproline (HP)/creatinine–was also significantly shorter (median 29 days) in the 30 mg group compared with the other two groups (20 mg: 43 days and 10 mg: 71 days). Long-term follow-up data up to 33 months from the start of the study indicated that AP remained below baseline levels for all patients. Histologic evaluation of bone formed during risedronate therapy demonstrated that normal lamellar bone was formed as opposed to woven pagetic bone, with no evidence of osteomalacia. Risedronate was well tolerated. Transient decreases in serum calcium and increases in serum intact parathyroid hormone were observed, consistent with the pharmacology of risedronate. In conclusion, risedronate administered at daily doses of 10, 20, and 30 mg for 28 days was effective in reducing the biochemical indices of disease activity in patients with severe Paget's disease of bone. A daily dose of 30 mg was most effective without compromising safety or tolerability.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002239900584
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  • 7
    Digitale Medien
    Digitale Medien
    Relative potency of controlled-release oxycodone and controlled-release morphine in a postoperative pain model (1999)
    Springer
    European journal of clinical pharmacology 55 (1999), S. 425-429 
    Details
    ISSN: 1432-1041
    Schlagwort(e): Key words Oxycodone ; Morphine ; Controlled-release formulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract Objective: The relative analgesic potency of single doses of oral controlled-release oxycodone and oral controlled-release morphine were compared in a randomized, double-blind trial using a postoperative pain model. Methods: Women (n = 169) with moderate to severe pain following abdominal hysterectomy received single oral doses of controlled-release oxycodone, 20 mg or 40 mg, or controlled-release morphine, 45 mg or 90 mg. Assessments were made at 30 min, 60 min, then hourly after dosing for 12 h or until remedication. Results: The most precise estimates of relative potency showed that controlled-release oxycodone was 1.8 times more potent than controlled-release morphine for total effect (95% confidence limits 1.09–2.42; lambda 0.44) and 2.2 times more potent for peak effect (95% confidence limits 0.96–4.59; lambda 0.71). Controlled-release oxycodone at doses of 20 mg or 40 mg was comparable with controlled-release morphine at doses of 45 mg or 90 mg, respectively, for total and peak analgesic effects. For the two higher doses, time to peak relief was approximately 1 h shorter with controlled-release oxycodone than with controlled-release morphine. Most patients reported onset of analgesia within 1 h with all doses. Side effects were similar with the two opioids. Conclusion: Oral controlled-release oxycodone was twice as potent as oral controlled-release morphine in this single-dose, relative potency assay. When converting patients from oral morphine to oral oxycodone, an initial oral oxycodone dose of one-half the oral morphine dose is recommended.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002280050651
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  • 8
    Digitale Medien
    Digitale Medien
    Variation in condition of coastal Newfoundland 0-group Atlantic cod (Gadus morhua): field and laboratory studies using simple condition indices (1999)
    Springer
    Marine biology 133 (1999), S. 611-620 
    Details
    ISSN: 1432-1793
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Demersal 0-group Atlantic cod (Gadus morhua L.) were collected in Trinity Bay, Newfoundland, Canada, between August 1993 and January 1994. Diet composition and simple indices of condition (hepato-somatic index, condition factors and body ash content) were determined. Laboratory experiments were also conducted to determine whether simple indices of condition reflect differences in energy intake (ration level) and to determine minimum index of condition values, assessed from 0-group cod that died due to exhaustion of their energy reserves. Determination of lower critical indices of condition provided a meaningful interpretation of field data on feeding, condition and survival of 0-group cod. In the wild, indices of condition reflecting variation in liver and muscle energy reserves of cod increased rapidly with the consumption of Calanus finmarchicus, which exhibited a high incidence of oil sacs, and declined abruptly when this lipid-rich prey was no longer consumed. Liver and muscle condition of 0-group cod from the field varied seasonally, but their condition was consistently above that of cod that died in the laboratory. Laboratory studies, using three ration levels, revealed that condition indices differed over time and among ration levels. Indices of condition representing variation in muscle energy reserves exhibited a steady decline once the hepato-somatic index fell below about 2.0. We interpret this as evidence for depletion of lipids first and then proteins, a pattern similar to that of larger juveniles and adults. We conclude that as long as 0-group cod are above a “safe” level of condition their body length can still increase even when condition is declining.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002270050501
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  • 9
    Digitale Medien
    Digitale Medien
    Tirapazamine: A new drug producing tumor specific enhancement of platinum-based chemotherapy in non-small-cell lung cancer (1999)
    Springer
    Annals of oncology 10 (1999), S. 29-33 
    Details
    ISSN: 1569-8041
    Schlagwort(e): carboplatin ; cisplatin ; hypoxia ; NSCLC ; p53 ; tirapazamine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Tirapazamine (TPZ), a new anti-cancer drug activated to a toxic free radical under hypoxic conditions, produces a tumor specific potentiation of cell kill by cisplatin. In the present study we discuss the mechanism and clinical potential of this effect, as well as investigate the influence of p53 mutations on the activity of TPZ. Materials and methods: For in vitro experiments we have used mouse SCCVII tumor cells, minimally transformed mouse embryo fibroblasts (MEFs) from wild-type and p53 knockout mice, and several human NSCLC cell lines. For in vivo experiments we have used RIF-1 tumors implanted subcutaneously into C3H mice. Results: Prior injection of TPZ into tumor-bearing mice markedly potentiated tumor cell kill by cisplatin, but produced no effect on systemic toxicity. The maximum potentiation occurred when TPZ was injected two to three hours prior to cisplatin administration. Experiments performed with cells in vitro showed a similar synergistic interaction between the two drugs when cells were exposed to TPZ under hypoxic conditions prior to exposure to cisplatin. Experiments with MEFs from either p53wild-type or p53-knockout mice showed no influence of p53on the sensitivity of cells to killing by TPZ under hypoxia. A similar lack of influence of p53 on the toxicity to TPZ was obtained for a panel of NSCLC cell lines. Conclusions: TPZ is a novel anticancer drug that produces tumor selective potentiation of cisplatin and carboplatin in both pre-clinical and clinical studies. The fact that the drug produces no potentiation of the systemic side effects of these drugs, or of other anticancer drugs used in combination with platinum in NSCLC, suggests that TPZ could become a useful agent in the treatment of lung cancer.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008391819103
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  • 10
    Digitale Medien
    Digitale Medien
    Fatal head injury in children: a new approach to scoring axonal and vascular damage (1999)
    Springer
    Child's nervous system 15 (1999), S. 322-328 
    Details
    ISSN: 1433-0350
    Schlagwort(e): Key words Traumatic brain injury ; Diffuse axonal injury ; β-Amyloid precursor protein ; Tolerance criteria ; Motor vehicle accidents
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  As part of a multidisciplinary study of brain damage in children fatally injured in motor vehicle accidents, a simple method to quantify and visualise the distribution and extent of injury has been developed. Vascular and axonal injury were assessed using coronal brain sections stained for haematoxylin and eosin, or reacted immunohistochemically for β-amyloid precursor protein. Subsequent analysis was carried out using NIH Image software, and the resulting information is displayed in schematic diagrams. These summary diagrams simply and clearly show the distribution of injury in both the coronal and horizontal planes. This technique offers an advantage over previous scoring methods in that it provides both a quantitative and a visual summary of the distribution and extent of brain injury. This information can then be used to compare the injury distribution and severity with estimated impact points and acceleration data.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003810050403
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