329 research outputs found
Computer programs and documentation
Various statistical tests that were used to check out random number generators are described. A total of twelve different tests were considered, and from these, six were chosen to be used. The frequency test, max t test, run test, lag product test, gap test, and the matrix test are included
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Modeling and Testing of Unbalanced Loading and Voltage Regulation
This report covers work to (1) develop and validate distribution circuit models, (2) determine optimum distributed generator operating conditions, and (3) determine distributed generation penetration limits
Contrasts in Tick Innate Immune Responses to Borrelia burgdorferi challenge: Immuno-tolerance in Ixodes scapularis versus Immunocompetence in Dermacentor variabilis (Acari: Ixodidae).
The blacklegged tick, Ixodes scapularis Say, transmits the Lyme disease spirochete (Borrelia burgdorferi), whereas the American dog tick, Dermacentor variabilis (Say), is unable to transmit the bacterium. We compared the innate immune response of these ticks against spirochetes directly inoculated into the hemocoel cavity of ticks. In I. scapularis, some Borrelia were found associated with hemocytes, while numerous other spiral-shaped, intact bacteria remained free in the hemolymph. In contrast, in D. variabilis only remnants of the bacteria were evident in the hemolymph, indicating lysis; intact spirochetes were rare. Spirochetes were observed bound to or within the organs of both tick species, although many more spirochetes were found associated with the I. scapularis organs. The few spirochetes observed with the D. variabilis organs appeared to be dead because D. variabilis tissues rarely contained culturable bacteria, unlike I. scapularis tissues. When spirochetes were incubated with I. scapularis hemolymph plasma in vitro, bacterial survival and motility were not reduced. In contrast, incubation of spirochetes with D. variabilis hemolymph plasma resulted in \u3e 50% of the spirochetes becoming nonmotile by 45 min. The differences in the responses of the two different tick species indicate that I. scapularis is immunotolerant when challenged with B. burgdorferi and dependent on a slow phagocytic response to clear Borrelia from the hemolymph. In contrast, D. variabilis is highly immunocompetent (i.e., innate immunity), using plasma borreliacidal factors and a rapid increase in phagocytic cells to clear the infection and limit tissue invasion
Glass Capillary Tube Feeding: A Method for Infecting Nymphal Ixodes scapularis (Acari: Ixodidae) with the Lyme Disease Spirochete Borrelia burgdorferi
We evaluated an artificial capillary feeding method to infect nymphal Ixodes scapularis (Say) ticks with Borrelia burgdorferi, the causative agent of Lyme disease. Thirty to 70% of the nymphs were infected after feeding for 2.5 h from glass capillary tubes filled with a solution of spirochetes. Capillary infection was stable and persisted in the nymphs for at least 10 d after feeding. Capillary feeding also maintained natural vector competence patterns because I. scapularis ticks acquired infection unlike Dermacentor variablis (Say), which did not become infected. Capillary infected I. scapularis nymphs were capable of transmitting the infection to naive mice although not as efficiently as naturally infected nymphs. The capillary infection method is convenient and is a better alternative to syringe inoculation as a means of infecting animals with B. burgdorferi
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Modeling and Verification of Distributed Generation and Voltage Regulation Equipment for Unbalanced Distribution Power Systems; Annual Subcontract Report, June 2007
This report summarizes the development of models for distributed generation and distribution circuit voltage regulation equipment for unbalanced power systems and their verification through actual field measurements
A structural role for arginine in proteins: Multiple hydrogen bonds to backbone carbonyl oxygens
We propose that arginine side chains often play a previously unappreciated general structural role in the maintenance of tertiary structure in proteins, wherein the positively charged guanidinium group forms multiple hydrogen bonds to backbone carbonyl oxygens. Using as a criterion for a “structural” arginine one that forms 4 or more hydrogen bonds to 3 or more backbone carbonyl oxygens, we have used molecular graphics to locate arginines of interest in 4 proteins: Arg 180 in Thermus thermophilus manganese superoxide dismutase, Arg 254 in human carbonic anhydrase II, Arg 31 in Streptomyces rubiginosus xylose isomerase, and Arg 313 in Rhodospirillum rubrum ribulose‐1,5‐bisphosphate carboxylase/oxygenase. Arg 180 helps to mold the active site channel of superoxide dismutase, whereas in each of the other enzymes the structural arginine is buried in the “mantle” (i.e., inside, but near the surface) of the protein interior well removed from the active site, where it makes 5 hydrogen bonds to 4 backbone carbonyl oxygens. Using a more relaxed criterion of 3 or more hydrogen bonds to 2 or more backbone carbonyl oxygens, arginines that play a potentially important structural role were found in yeast enolase, Bacillus stearothermophilus glyceraldehyde‐3‐phosphate dehydrogenase, bacteriophage T4 and human lysozymes, Enteromorpha prolifera plastocyanin, HIV‐1 protease, Trypanosoma brucei brucei and yeast triosephosphate isomerases, and Escherichia coli trp aporepressor (but not trp repressor or the trp repressor/operator complex). In addition to helping form the active site funnel in superoxide dismutase, the structural arginines found in this study play such diverse roles as stapling together 3 strands of backbone from different regions of the primary sequence, and tying α‐helix to α‐helix, βturn to β‐turn, and subunit to subunit. Copyright © 1994 The Protein Societ
Separation of VUV/UV photons and reactive particles in the effluent of a He/O2 atmospheric pressure plasma jet
Cold atmospheric pressure plasmas can be used for treatment of living tissues
or for inactivation of bacteria or biological macromolecules. The treatment is
usually characterized by a combined effect of UV and VUV radiation, reactive
species, and ions. This combination is usually beneficial for the effectiveness
of the treatment but it makes the study of fundamental interaction mechanisms
very difficult. Here we report on an effective separation of VUV/UV photons and
heavy reactive species in the effluent of a micro scale atmospheric pressure
plasma jet (-APPJ). The separation is realized by an additional flow of
helium gas under well-defined flow conditions, which deflects heavy particles
in the effluent without affecting the VUV and UV photons. Both components of
the effluent, the photons and the reactive species, can be used separately or
in combination for sample treatment. The results of treatment of a model plasma
polymer film and vegetative Bacillus subtilis and Escherichia coli cells are
shown and discussed. A simple model of the He gas flow and reaction kinetics of
oxygen atoms in the gas phase and at the surface is used to provide a better
understanding of the processes in the plasma effluent. The new jet
modification, called X-Jet for its appearance, will simplify the investigation
of interaction mechanisms of atmospheric pressure plasmas with biological
samples.Comment: 10 pages, 7 figures, submitted to Journal of Physics D: Applied
Physic
Unsuspected Dengue as a Cause of Acute Febrile Illness in Children and Adults in Western Nicaragua
Dengue is an emerging infectious disease of global significance. Suspected dengue, especially in children in Nicaragua’s heavily-urbanized capital of Managua, has been well documented, but unsuspected dengue among children and adults with undifferentitated fever has not
Utility Scores and Treatment Preferences for Clinical Early-Stage Cervical Cancer
AbstractObjectivesTo determine utility scores for health states relevant to the treatment of early-stage, high-risk cervical cancer.MethodsSeven descriptive health states incorporating the physical and emotional aspects of medical treatment, recovery, and prognosis were developed. Forty-five female volunteers valuated each health state using the visual analogue score (VAS) and time trade off (TTO) methods. Treatment options were ranked by mean and median TTO scores. The 95% confidence intervals were calculated to determine the statistical significance of ranking preferences. The Wilcoxon rank-sum test was used to compare central tendencies related to age, race, parity, and subject history of abnormal cervical cytology.ResultsVAS and TTO scores were highly correlated. Volunteers ranked minimally invasive radical hysterectomy with low-risk features as most preferred (mean TTO = 0.96; median TTO = 1.00) and aborted radical hysterectomy followed by chemoradiation as least preferred (mean TTO = 0.69; median TTO = 0.83). Health states that included radical surgery were ranked higher than those that included chemoradiation, either in the adjuvant or primary setting. When survival was comparable, volunteers rated radical hysterectomy with high-risk pathology followed by adjuvant chemoradiation (mean TTO = 0.78; median TTO = 0.92; 95% CI: 0.69–0.87) similarly to chemoradiation alone (mean TTO = 0.76; median TTO 0.90; 95% CI: 0.66–0.86; p = NS). Utility scores for the majority of health states were not significantly associated with age, race, parity, or subject history of abnormal cervical cytology.ConclusionSubjects consistently preferred surgical excision to treat early-stage, high-risk cervical cancer and chose a minimally invasive approach. Such utility scores can be used to incorporate quality-of-life effects into comparative-effectiveness models for cervical cancer
Universal Mask Usage for Reduction of Respiratory Viral Infections After Stem Cell Transplant: A Prospective Trial
Background. Respiratory viral infections (RVIs) are frequent complications of hematopoietic stem cell transplant (HSCT). Surgical masks are a simple and inexpensive intervention that may reduce nosocomial spread
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