114 research outputs found
Deuteron photodisintegration with polarized photons at astrophysical energies
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 and amplitudes simultaneously. The isoscalar
contribution is also taken exactly into account. From the existing experimental
measurement on doubly polarized thermal neutron capture, it is seen that the
isoscalar 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
contribution at astrophysical energies.Comment: 5 Pages, Latex-2
Scattering Polarization in the Presence of Magnetic and Electric Fields
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 profiles and rotation of the plane of polarization in the
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
Integrating a mobile-learning platform for enhancing clinical teaching:the learners' perspective
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.
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.
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
Fluctuations in Serum magnesium and Systemic Arterial Blood Pressures during the Menstrual Cycle in young reproductive women
Introduction: The menstrual cycle involves a sequence of structural, functional, and hormonal changes in the
reproductive system. This is linked and controlled by cyclical fluctuations in the levels of FSH, LH, estrogen,
and progesterone. Because of these cyclical fluctuations, there might also be associated cyclical changes of
magnesium and systemic arterial blood pressures during the menstrual cycle. Purpose: To assess the changes in
serum magnesium level and systemic arterial blood pressures during the menstrual cycle in young reproductive
women. Methodology: the sample population is 40 apparently healthy young reproductive-aged 18- 25years
female students from the University of Medicine, Magway participated in this study. Systemic arterial blood
pressures were measured by indirect method. The serum magnesium level was measured by spectrophotometry.
These measurements were done in the early follicular phase (EF), the peri-ovulatory phase (PO), and the midluteal phase (ML) of the menstrual cycle. The serum magnesium levels were significantly (p <0.001) lower, and
the systolic blood pressures were significantly higher (p <0.05) in the PO than the EF and the ML. In the EF,
there was a significant negative correlation between serum magnesium level and diastolic blood pressure (r= -
0.374, p <0.05) and mean arterial pressure (r = -0.354, p < 0.05) but no significant correlation with systolic blood
pressure. In the PO, there was no significant correlation between serum magnesium level and systemic arterial
blood pressures. In the ML, there was significant negative correlation between serum magnesium level and
systolic blood pressure (r = -0.651, p <0.001), diastolic blood pressure (r = -0.607, p <0.001), and mean arterial
pressure (r = -0.661, p <0.001). Conclusion: The study concludes that serum magnesium level has a negative
effect on blood pressure changes and the blood pressure-lowering effect of magnesium. These changes are
related to the fluctuation of estrogen levels during the menstrual cycle.
KEYWORDS: Serum magnesium, systemic arterial blood pressures, menstrual cycle reproductive syste
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