95 research outputs found

    Deuteron photodisintegration with polarized photons at astrophysical energies

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    Following precise experimental studies at the Duke Free-Electron Laser Laboratory, we discuss photodisintegration of deuterons with 100% linearly polarized photons using a model independent theoretical approach taking together M1M1 and E1E1 amplitudes simultaneously. The isoscalar M1sM1_s contribution is also taken exactly into account. From the existing experimental measurement on doubly polarized thermal neutron capture, it is seen that the isoscalar M1sM1_s contribution could be of the same order of magnitude as the experimentally measured cross sections at energies relevant to Big Bang Nucleosynthesis (BBN). Therefore appropriate measurements on deuteron photodisintegration are suggested to empirically determine the M1sM1_s contribution at astrophysical energies.Comment: 5 Pages, Latex-2

    モダリティ ノ カンテン カラ ミル ソウダ ト ヨウダ ノ ソウイ

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    Scattering Polarization in the Presence of Magnetic and Electric Fields

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    The polarization of radiation by scattering on an atom embedded in combined external quadrupole electric and uniform magnetic fields is studied theoretically. Limiting cases of scattering under Zeeman effect and Hanle effect in weak magnetic fields are discussed. The theory is general enough to handle scattering in intermediate magnetic fields (Hanle-Zeeman effect) and for arbitrary orientation of magnetic field. The quadrupolar electric field produces asymmetric line shifts and causes interesting level-crossing phenomena either in the absence of an ambient magnetic field or in its presence. It is shown that the quadrupolar electric field produces an additional depolarization in the Q/IQ/I profiles and rotation of the plane of polarization in the U/IU/I profile over and above that arising from magnetic field itself. This characteristic may have a diagnostic potential to detect steady state and time varying electric fields that surround radiating atoms in Solar atmospheric layers.Comment: 41 pages, 6 figure

    High rate of virological failure and low rate of switching to second-line treatment among adolescents and adults living with HIV on first-line ART in Myanmar, 2005-2015.

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    BACKGROUND: The number of people living with HIV on antiretroviral treatment (ART) in Myanmar has been increasing rapidly in recent years. This study aimed to estimate rates of virological failure on first-line ART and switching to second-line ART due to treatment failure at the Integrated HIV Care program (IHC). METHODS: Routinely collected data of all adolescent and adult patients living with HIV who were initiated on first-line ART at IHC between 2005 and 2015 were retrospectively analyzed. The cumulative hazard of virological failure on first-line ART and switching to second-line ART were estimated. Crude and adjusted hazard ratios were calculated using the Cox regression model to identify risk factors associated with the two outcomes. RESULTS: Of 23,248 adults and adolescents, 7,888 (34%) were tested for HIV viral load. The incidence rate of virological failure among those tested was 3.2 per 100 person-years follow-up and the rate of switching to second-line ART among all patients was 1.4 per 100 person-years follow-up. Factors associated with virological failure included: being adolescent; being lost to follow-up at least once; having WHO stage 3 and 4 at ART initiation; and having taken first-line ART elsewhere before coming to IHC. Of the 1032 patients who met virological failure criteria, 762 (74%) switched to second-line ART. CONCLUSIONS: We found high rates of virological failure among one third of patients in the cohort who were tested for viral load. Of those failing virologically on first-line ART, about one quarter were not switched to second-line ART. Routine viral load monitoring, especially for those identified as having a higher risk of treatment failure, should be considered in this setting to detect all patients failing on first-line ART. Strategies also need to be put in place to prevent treatment failure and to treat more of those patients who are actually failing

    Long-term outcomes of second-line antiretroviral treatment in an adult and adolescent cohort in Myanmar.

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    BACKGROUND: Myanmar has a high burden of Human Immunodeficiency Virus (HIV) and second-line antiretroviral treatment (ART) has been available since 2008 in the public health sector. However, there have been no published data about the outcomes of such patients until now. OBJECTIVE: To assess the treatment and programmatic outcomes and factors associated with unfavorable outcomes (treatment failure, death and loss to follow-up from care) among people living with HIV (aged ≥ 10 years) receiving protease inhibitor-based second-line ART under the Integrated HIV Care Program in Myanmar between October 2008 and June 2015. DESIGN: Retrospective cohort study using routinely collected program data. RESULTS: Of 824 adults and adolescents on second-line ART, 52 patients received viral load testing and 19 patients were diagnosed with virological failure. However, their treatment was not modified. At the end of a total follow-up duration of 7 years, 88 (11%) patients died, 35 (4%) were lost to follow-up, 21 (2%) were transferred out to other health facilities and 680 (83%) were still under care. The incidence rate of unfavorable outcomes was 7.9 patients per 100 person years follow-up. Patients with a history of injecting drug use, with a history of lost to follow-up, with a higher baseline viral load and who had received didanosine and abacavir had a higher risk of unfavorable outcomes. Patients with higher baseline C4 counts, those having taken first-line ART at a private clinic, receiving ART at decentralized sites and taking zidovudine and lamivudine had a lower risk of unfavorable outcomes. CONCLUSIONS: Long-term outcomes of patients on second-line ART were relatively good in this cohort. Virological failure was relatively low, possibly because of lack of viral load testing. No patient who failed on second-line ART was switched to third-line treatment. The National HIV/AIDS Program should consider making routine viral load monitoring and third-line ART drugs available after a careful cost-benefit analysis

    Extracellular Electron Uptake by Two Methanosarcina Species

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    Direct electron uptake by prokaryotes is a recently described mechanism with a potential application for energy and CO2 storage into value added chemicals. Members of Methanosarcinales, an environmentally and biotechnologically relevant group of methanogens, were previously shown to retrieve electrons from an extracellular electrogenic partner performing Direct Interspecies Electron Transfer (DIET) and were therefore proposed to be electroactive. However, their intrinsic electroactivity has never been examined. In this study, we tested two methanogens belonging to the genus Methanosarcina, M. barkeri, and M. horonobensis, regarding their ability to accept electrons directly from insoluble electron donors like other cells, conductive particles and electrodes. Both methanogens were able to retrieve electrons from Geobacter metallireducens via DIET. Furthermore, DIET was also stimulated upon addition of electrically conductive granular activated carbon (GAC) when each was co-cultured with G. metallireducens. However, when provided with a cathode poised at −400 mV (vs. SHE), only M. barkeri could perform electromethanogenesis. In contrast, the strict hydrogenotrophic methanogen, Methanobacterium formicicum, did not produce methane regardless of the type of insoluble electron donor provided (Geobacter cells, GAC or electrodes). A comparison of functional gene categories between the two Methanosarcina showed differences regarding energy metabolism, which could explain dissimilarities concerning electromethanogenesis at fixed potentials. We suggest that these dissimilarities are minimized in the presence of an electrogenic DIET partner (e.g., Geobacter), which can modulate its surface redox potentials by adjusting the expression of electroactive surface proteins

    Bioactive compounds screening, antimicrobial activities of leave extract from two palatable plants: Piper betle and Murraya koenigii (Curry leaves)

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    Introduction: Piper betle Linn is one of the most commonly used compounding plants for ethno-medical purposes, with its extract generally used in modern products to enrich their functional efficacy. The extraction methods always lead to differences in the antimicrobial efficacy of methanol extracts of bioactive compounds. Purpose: The study was conducted to screen for bioactive compounds and determine their antimicrobial efficacy in a methanol extract of Piper betle and Murraya koenigi leaves from five different regions. Methodology: The phytochemical screening done according to the procedure that is implied in from Patil, et.al, with minor modifications by the researchers of the current study. Antimicrobial activity was determined; efficacy was measured by disc diffusion analysis. Results: Phytochemical screening revealed the presence of saponin, tannin, terpenoids, alkaloids and flavonoids in the extracts. The methanolic extract of betel leaves from all the selected regions except from Bau exhibited antimicrobial activities. Among them, extract from Kuching and Simunjan have no effect on E. coli. The methanolic extract of curry leaves from Kuching, Balai ringai and Bau have antimicrobial activities against Staph aureus and those from Balai ringai is also active against E.coli. Conclusion: Although there were previous reports of phytochemical screening and antimicrobial activities from the extract of these plants, there were still lack of research conducted on the specimens especially from our local community (Sarawak). The outcome of this study will help us to identify the bioactive compounds of the local samples and give us some pictures of their activities on how to ensure these plants can be brought forward based on the origin of the sample. KEYWORDS: Bioactive Compounds Screening, Antimicrobial Activities of Leave Extract, Palatable Plants, Piper betle and Murraya koenigii