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  • 1
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: OMEGA, a 60-beam, 351 nm, Nd:glass laser with an on-target energy capability of more than 40 kJ, is a flexible facility that can be used for both direct- and indirect-drive targets and is designed to ultimately achieve irradiation uniformity of 1% on direct-drive capsules with shaped laser pulses (dynamic range (approximately-greater-than)400:1). The OMEGA program for the next five years includes plasma physics experiments to investigate laser–matter interaction physics at temperatures, densities, and scale lengths approaching those of direct-drive capsules designed for the 1.8 MJ National Ignition Facility (NIF); experiments to characterize and mitigate the deleterious effects of hydrodynamic instabilities; and implosion experiments with capsules that are hydrodynamically equivalent to high-gain, direct-drive capsules. Details are presented of the OMEGA direct-drive experimental program and initial data from direct-drive implosion experiments that have achieved the highest thermonuclear yield (1014 DT neutrons) and yield efficiency (1% of scientific breakeven) ever attained in laser-fusion experiments. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 432-449 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experimental data and hydrodynamic simulation results are presented for long-scale-length plasmas produced by the multibeam OMEGA fusion laser, with (approximately-less-than)1.5 kJ on target at wavelength 351 nm. The appropriately time-delayed beams from this system allow the production of millimeter-sized plasmas with (approximately-greater-than)1 keV electron temperatures maintained over extended periods of time ((approximately-greater-than)1 nsec). The two-dimensional plasma expansion and the temporal evolution of the electron temperature and density are found to be in very good agreement with simulations. The plasma thus produced forms an excellent tool for investigating laser–plasma interaction processes under conditions relevant to future laser-fusion reactor targets.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 2405-2407 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the temporal and the frequency response of metal-semiconductor-metal ultraviolet photodetectors fabricated on single-crystal GaN. The best devices show a fast 10%–90% rise time of ∼23 ps implying a bandwidth of 〉15 GHz. These time domain data have been corroborated by direct measurement of the power spectral content. From this a cutoff frequency, f3 dB, of ∼16 GHz has been obtained. Analysis in terms of reverse bias and geometric scaling indicates that the photodetectors are transit-time limited. Modeling of the temporal behavior indicates that a slow component in the time and frequency response data is a consequence of the hole drift velocity. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 34 (1998), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : Forest land managers are concerned about the effects of logging on soil erosion, streamflow, and water quality and are promoting the use of Best Management Practices (BMPs) to control impacts. To compare the effects of BMP implementation on streamwater quality, two of three small watersheds in Kentucky were harvested in 1983 and 1984, one with BMPs, the other without BMPs. There was no effect of clearcutting on stream temperatures. Streamflow increased by 17.8 cm (123 percent) on the BMP watershed during the first 17 months after cutting and by 20.6 cm (138 percent) on the Non-BMP watershed. Water yields remained significantly elevated compared to the uncut watershed 8 years after harvesting. Suspended sediment flux was 14 and 30 times higher on the BMP and Non-BMP Watersheds, respectively, than on the uncut watershed during treatment, and 4 and 6.5 times higher in the 17 months after treatment was complete. Clearcutting resulted in increased concentrations of nitrate, and other nutrients compared to the uncut watershed, and concentrations were highest on the non-BMP watershed. Recovery of biotic control over nutrient losses occurred within three years of clearcutting. The streamside buffer strip was effective in reducing the impact of clearcutting on water yield and sediment flux.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Plant Physiology 27 (1976), S. 71-94 
    ISSN: 0066-4294
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1365-2516
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary.  Treatment with contaminated plasma products before 1990 resulted in extraordinary prevalence rates of human immunodeficiency virus (HIV) and hepatitis B and C viruses (HBV, HCV). In the Second Multicentre Haemophilia Cohort Study (MHCS-II) during 2001–03, 30% of HCV-seropositive survivors had HIV and 4.6% were HBV carriers. Highly active antiretroviral therapy (HAART) radically altered the consequences of HIV/HCV coinfection. Whereas opportunistic infections predominated previously, current major complications are liver failure and bleeding (exacerbated by decreased clotting factor synthesis, hypersplenic thrombocytopenia, and oesophageal varices). Most HIV-positives in MHCS-II were HIV RNA-negative and had 〉 200 CD4+ cells µL−1, but only 59% were on HAART. With HIV, especially after 41 years of age, liver disease was apparent (jaundice in 5%, ascites 7%, hepatomegaly 9%, splenomegaly 19%). HAART increases survival but may contribute to various comorbidities. Without HIV, sustained HCV clearance is obtained in 〉 50% with combined pegylated interferons plus ribavirin, but data in haemophilic populations, especially with HIV, are limited. In MHCS-II, HCV RNA negativity was 41% following standard interferon plus ribavirin; among interferon-naïve participants (implying spontaneous HCV clearance), HCV RNA negativity was 12% with and 25% without HIV. Without HIV, spontaneous HCV clearance was much more likely with early age at infection and particularly with recent birth (late 1970s or early 1980s) but not with bleeding propensity or its treatment. Most (72%) participants had received no anti-HCV therapy. Hepatic and haematological conditions are likely to increase during the coming years unless most adult haemophiliacs are successfully treated for HIV, HCV or both.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Anaesthesia 52 (1997), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This is the story of the development of pancuronium bromide and David S. Savage's enormous contribution to the first rational structure–function approach to the design of a pharmaceutically useful drug.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-1432
    Keywords: Lymphocytes ; B cells ; T cells ; Antigen P1 ; Topoisomerase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary During the differentiation of the clonally distributed lymphocytes of mouse and man into mature resting B and T cells, their DNA becomes tightly packed into dense heterochromatin masses and exhibits very little transcriptional activity; it also becomes extensively nicked, containing some 3000–4000 single-strand breaks per diploid genome. The nuclear matrix is sparse and poorly organized and there are but trace amounts of the matrix-linked enzyme DNA topoisomerase II; the nucleus of these small cells is surrounded by a thin rim of cytoplasm. The resting cell can thus be considered (by analogy to a sperm cell) as a vector for transporting tightly packed and relatively inert genetic information to all parts of the body. When the lymphocyte is stimulated to enter a proliferative cycle by binding of appropriately presented antigen or mitogen to relevant membrane receptors, the cell enlarges, due to increased synthesis of protein; the dense heterochromatin is pulled out into very small clumps, as a result of an enormous growth in size as well as complexity of the nuclear matrix, and a great increase in transcriptional activity occurs. We have identified four nuclear matrix antigens that are very widely conserved in the evolution of eucaryotes and that occupy distinctive domains in interphase nuclei. Of particular interest is antigen P1, detected in organisms ranging from algae to mammals. By virtue of its location at the interface between nuclear envelope and chromatin, we propose that it plays a major and evolutionarily conserved role in chromatin organization and orientation in all eucaryotic cell types. Prior to these events, the DNA strand breaks are rejoined by a mechanism dependent on poly(ADP ribose) synthetase; rejoining of the breaks is required in order for the cells to enter the S phase of the cell cycle. Under certain experimental conditions, the induction of DNA topoisomerase II is clearly seen to precede DNA replication; topoisomerase II may be involved in some of the nuclear changes of blastogenesis. The evidence suggests that induction of single-strand breaks in DNA may be a general feature in the evolution of differentiated somatic cells. The selective advantage of the endogenously produced DNA strand breaks may be to provide an additional mechanism that prevents the differentiated cell from replicating its genome in the absence of an appropriate proliferative signal.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopic ultrasound — Intraoperative cholangiography — Laparoscopic cholecystectomy — Choledocholithiasis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: The laparoscopic ultrasound (US) probe provides a new modality for evaluating biliary anatomy during laparoscopic cholecystectomy (LC). Methods: We performed a laparoscopic US examination in 65 patients without suspected common bile duct (CBD) stones prior to the performance of a laparoscopic cholangiogram (IOC). We then compared the cost, time required, surgeon's assessment of difficulty, and interpretations of findings. Results: There was a significant difference in the cost of US versus the cost of IOC ($362 ± 12 versus $665 ± 12; p 〈 0.05). Surgeons who had performed 〉10 US (EXP) were compared with those who had performed ≤10 (NOV). There were significant differences between the EXP and NOV groups in ease of examination, visualization of biliary anatomy, and accuracy of measurement of the CBD. Conclusions: The use of laparoscopic US for the accurate evaluation of the CBD and biliary anatomy requires that the surgeon has surpassed the learning curve, which we have defined as having performed 〉10 US exams.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1573-2592
    Keywords: Cardiac transplantation ; immune complexes ; antithymocyte globulin antibodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Thirteen heart transplant patients receiving heterologous antithymocyte globulin were examined serially for the presence of circulating immune complexes, activation of complement, and antibodies to antihymocyte globulin. Using three independent assays, all patients were found to develop immune complexes at some time following transplantation, mostly as a consequence of antithymocyte globulin administration and infection. Simultaneous analysis of endogenous complement levels revealed C3 and C4 hypocomplementaemia in 28 and 44% of the samples, respectively. However, no correlation was evident between immune complex or complement levels and cardiac rejection assessed histologically in 64 endomyocardial biopsies. Serial analysis of antibodies to equine and rabbit antithymocyte globulin by solid-phase radio-immunoassay showed that 8 of 10 patients had significantly elevated values. Evidence was also obtained which indicated a substantial degree of cross-reactivity between the antibodies to these heterologous proteins. The results demonstrate a complex interplay of immune reactants relating to transplantation, infection, and immunosuppression therapy.
    Type of Medium: Electronic Resource
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