251 research outputs found

    Search for CP violation in D0 and D+ decays

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    A high statistics sample of photoproduced charm particles from the FOCUS (E831) experiment at Fermilab has been used to search for CP violation in the Cabibbo suppressed decay modes D+ to K-K+pi+, D0 to K-K+ and D0 to pi-pi+. We have measured the following CP asymmetry parameters: A_CP(K-K+pi+) = +0.006 +/- 0.011 +/- 0.005, A_CP(K-K+) = -0.001 +/- 0.022 +/- 0.015 and A_CP(pi-pi+) = +0.048 +/- 0.039 +/- 0.025 where the first error is statistical and the second error is systematic. These asymmetries are consistent with zero with smaller errors than previous measurements.Comment: 12 pages, 4 figure

    A Study of D0 --> K0(S) K0(S) X Decay Channels

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    Using data from the FOCUS experiment (FNAL-E831), we report on the decay of D0D^0 mesons into final states containing more than one KS0K^0_S. We present evidence for two Cabibbo favored decay modes, D0β†’KS0KS0Kβˆ’Ο€+D^0\to K^0_SK^0_S K^- \pi^+ and D0β†’KS0KS0K+Ο€βˆ’D^0\to K^0_SK^0_S K^+ \pi^-, and measure their combined branching fraction relative to D0β†’KΛ‰0Ο€+Ο€βˆ’D^0\to \bar{K} ^0\pi^+\pi^- to be Ξ“(D0β†’KS0KS0KΒ±Ο€βˆ“)Ξ“(D0β†’KΛ‰0Ο€+Ο€βˆ’)\frac{\Gamma(D^0\to K^0_SK^0_SK^{\pm}\pi^{\mp})}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0106 Β±\pm 0.0019 Β±\pm 0.0010. Further, we report new measurements of Ξ“(D0β†’KS0KS0KS0)Ξ“(D0β†’KΛ‰0Ο€+Ο€βˆ’)\frac{\Gamma(D^0\to K^0_SK^0_SK^0_S)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0179 Β±\pm 0.0027 Β±\pm 0.0026, Ξ“(D0β†’K0KΛ‰0)Ξ“(D0β†’KΛ‰0Ο€+Ο€βˆ’)\frac{\Gamma(D^0\to K^0\bar{K} ^0)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0144 Β±\pm 0.0032 Β±\pm 0.0016, and Ξ“(D0β†’KS0KS0Ο€+Ο€βˆ’)Ξ“(D0β†’KΛ‰0Ο€+Ο€βˆ’)\frac{\Gamma(D^0\to K^0_SK^0_S\pi^+\pi^-)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0208 Β±\pm 0.0035 Β±\pm 0.0021 where the first error is statistical and the second is systematic.Comment: 11 pages, 3 figures, typos correcte

    Quasispecies Theory and the Behavior of RNA Viruses

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    A large number of medically important viruses, including HIV, hepatitis C virus, and influenza, have RNA genomes. These viruses replicate with extremely high mutation rates and exhibit significant genetic diversity. This diversity allows a viral population to rapidly adapt to dynamic environments and evolve resistance to vaccines and antiviral drugs. For the last 30 years, quasispecies theory has provided a population-based framework for understanding RNA viral evolution. A quasispecies is a cloud of diverse variants that are genetically linked through mutation, interact cooperatively on a functional level, and collectively contribute to the characteristics of the population. Many predictions of quasispecies theory run counter to traditional views of microbial behavior and evolution and have profound implications for our understanding of viral disease. Here, we discuss basic principles of quasispecies theory and describe its relevance for our understanding of viral fitness, virulence, and antiviral therapeutic strategy

    Impact of Chronic Kidney Disease on the Presence and Severity of Aortic Stenosis in Patients at High Risk for Coronary Artery Disease

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    <p>Abstract</p> <p>Objective</p> <p>We evaluated the impact of chronic kidney disease (CKD) on the presence and severity of aortic stenosis (AS) in patients at high risk for coronary artery disease (CAD).</p> <p>Methods</p> <p>One hundred and twenty consecutive patients who underwent invasive coronary angiography were enrolled. Aortic valve area (AVA) was calculated by the continuity equation using transthoracic echocardiography, and was normalized by body surface area (AVA index).</p> <p>Results</p> <p>Among all 120 patients, 78% had CAD, 55% had CKD (stage 3: 81%; stage 4: 19%), and 34% had AS (AVA < 2.0cm<sup>2</sup>). Patients with AS were older, more often female, and had a higher frequency of CKD than those without AS, but the prevalence of CAD and most other coexisting conventional risk factors was similar between patients with and without AS. Multivariate linear regression analysis indicated that only CKD and CAD were independent determinants of AVA index with standardized coefficients of -0.37 and -0.28, respectively. When patients were divided into 3 groups (group 1: absence of CKD and CAD, n = 16; group 2: presence of either CKD or CAD, n = 51; and group 3: presence of both CKD and CAD, n = 53), group 3 had the smallest AVA index (1.19 Β± 0.30*# cm<sup>2</sup>/m<sup>2</sup>, *p < 0.05 vs. group 1: 1.65 Β± 0.32 cm<sup>2</sup>/m<sup>2</sup>, and #p < 0.05 vs. group 2: 1.43 Β± 0.29* cm<sup>2</sup>/m<sup>2</sup>) and the highest peak velocity across the aortic valve (1.53 Β± 0.41*# m/sec; *p < 0.05 vs. group 1: 1.28 Β± 0.29 m/sec, and #p < 0.05 vs. group 2: 1.35 Β± 0.27 m/sec).</p> <p>Conclusion</p> <p>CKD, even pre-stage 5 CKD, has a more powerful impact on the presence and severity of AS than other conventional risk factors for atherosclerosis in patients at high risk for CAD.</p

    DNA Damage and Reactive Nitrogen Species are Barriers to Vibrio cholerae Colonization of the Infant Mouse Intestine

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    Ingested Vibrio cholerae pass through the stomach and colonize the small intestines of its host. Here, we show that V. cholerae requires at least two types of DNA repair systems to efficiently compete for colonization of the infant mouse intestine. These results show that V. cholerae experiences increased DNA damage in the murine gastrointestinal tract. Agreeing with this, we show that passage through the murine gut increases the mutation frequency of V. cholerae compared to liquid culture passage. Our genetic analysis identifies known and novel defense enzymes required for detoxifying reactive nitrogen species (but not reactive oxygen species) that are also required for V. cholerae to efficiently colonize the infant mouse intestine, pointing to reactive nitrogen species as the potential cause of DNA damage. We demonstrate that potential reactive nitrogen species deleterious for V. cholerae are not generated by host inducible nitric oxide synthase (iNOS) activity and instead may be derived from acidified nitrite in the stomach. Agreeing with this hypothesis, we show that strains deficient in DNA repair or reactive nitrogen species defense that are defective in intestinal colonization have decreased growth or increased mutation frequency in acidified nitrite containing media. Moreover, we demonstrate that neutralizing stomach acid rescues the colonization defect of the DNA repair and reactive nitrogen species defense defective mutants suggesting a common defense pathway for these mutants

    Toro Times: Raising Our Voices!

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    During the Spring 2019 semester, Dr. Noah Asher Golden\u27s Teaching of Writing K-12 students partnered with the Journalism class at Yorba Academy for the Arts. Through collaboration over a four-month period, Chapman\u27s future teachers and Yorba\u27s junior high journalists engaged a deep writing process to write a series of features, editorials, and news articles related to a number of global issues. Thank you to Principal Preciado-Martin, former principal Tracy Knibb, Mrs. Andrea Lopez, Mrs. Kori Shelton, and the Lloyd E. and Elisabeth H. Klein Family Foundation for supporting this project.https://digitalcommons.chapman.edu/yorba-chapman/1004/thumbnail.jp

    INSL3 in the Ruminant: A Powerful Indicator of Gender- and Genetic-Specific Feto-Maternal Dialogue

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    The hormone Insulin-like peptide 3 (INSL3) is a major secretory product of the Leydig cells from both fetal and adult testes. Consequently, it is a major gender-specific circulating hormone in the male fetus, where it is responsible for the first phase of testicular descent, and in the adult male. In most female mammals, circulating levels are very low, corresponding to only a small production of INSL3 by the mature ovaries. Female ruminants are exceptional in exhibiting high INSL3 gene expression by the thecal cells of antral follicles and by the corpora lutea. We have developed a specific and sensitive immunoassay to measure ruminant INSL3 and show that, corresponding to the high ovarian gene expression, non-pregnant adult female sheep and cows have up to four times the levels observed in other female mammals. Significantly, this level declines during mid-pregnancy in cows carrying a female fetus, in which INSL3 is undetectable. However, in cows carrying a male fetus, circulating maternal INSL3 becomes elevated further, presumably due to the transplacental transfer of fetal INSL3 into the maternal circulation. Within male fetal blood, INSL3 is high in mid-pregnancy (day 153) corresponding to the first transabdominal phase of testicular descent, and shows a marked dependence on paternal genetics, with pure bred or hybrid male fetuses of Bos taurus (Angus) paternal genome having 30% higher INSL3 levels than those of Bos indicus (Brahman) paternity. Thus INSL3 provides the first example of a gender-specific fetal hormone with the potential to influence both placental and maternal physiology

    Telephone Consultation for Improving Health of People Living with or at Risk of HIV: A Systematic Review

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    BACKGROUND: Low cost, effective interventions are needed to deal with the major global burden of HIV/AIDS. Telephone consultation offers the potential to improve health of people living with HIV/AIDS cost-effectively and to reduce the burden on affected people and health systems. The aim of this systematic review was to assess the effectiveness of telephone consultation for HIV/AIDS care. METHODS: We undertook a comprehensive search of peer-reviewed and grey literature. Two authors independently screened citations, extracted data and assessed the quality of randomized controlled trials which compared telephone interventions with control groups for HIV/AIDS care. Telephone interventions were voice calls with landlines or mobile phones. We present a narrative overview of the results as the obtained trials were highly heterogeneous in design and therefore the data could not be pooled for statistical analysis. RESULTS: The search yielded 3321 citations. Of these, nine studies involving 1162 participants met the inclusion criteria. The telephone was used for giving HIV test results (one trial) and for delivering behavioural interventions aimed at improving mental health (four trials), reducing sexual transmission risk (one trial), improving medication adherence (two trials) and smoking cessation (one trial). Limited effectiveness of the intervention was found in the trial giving HIV test results, in one trial supporting medication adherence and in one trial for smoking cessation by telephone. CONCLUSIONS: We found some evidence of the benefits of interventions delivered by telephone for the health of people living with HIV or at risk of HIV. However, only limited conclusions can be drawn as we only found nine studies for five different interventions and they mainly took place in the United States. Nevertheless, given the high penetration of low-cost mobile phones in countries with high HIV endemicity, more evidence is needed on how telephone consultation can aid in the delivery of HIV prevention, treatment and care
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