151 research outputs found

    Nuclear structure of 30S and its implications for nucleosynthesis in classical novae

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    The uncertainty in the 29P(p,gamma)30S reaction rate over the temperature range of 0.1 - 1.3 GK was previously determined to span ~4 orders of magnitude due to the uncertain location of two previously unobserved 3+ and 2+ resonances in the 4.7 - 4.8 MeV excitation region in 30S. Therefore, the abundances of silicon isotopes synthesized in novae, which are relevant for the identification of presolar grains of putative nova origin, were uncertain by a factor of 3. To investigate the level structure of 30S above the proton threshold (4394.9(7) keV), a charged-particle spectroscopy and an in-beam gamma-ray spectroscopy experiments were performed. Differential cross sections of the 32S(p,t)30S reaction were measured at 34.5 MeV. Distorted wave Born approximation calculations were performed to constrain the spin-parity assignments of the observed levels. An energy level scheme was deduced from gamma-gamma coincidence measurements using the 28Si(3He,n-gamma)30S reaction. Spin-parity assignments based on measurements of gamma-ray angular distributions and gamma-gamma directional correlation from oriented nuclei were made for most of the observed levels of 30S. As a result, the resonance energies corresponding to the excited states in 4.5 MeV - 6 MeV region, including the two astrophysically important states predicted previously, are measured with significantly better precision than before. The uncertainty in the rate of the 29P(p,gamma)30S reaction is substantially reduced over the temperature range of interest. Finally, the influence of this rate on the abundance ratios of silicon isotopes synthesized in novae are obtained via 1D hydrodynamic nova simulations.Comment: 22 pages, 12 figure

    In situ, real-time visualization of electrochemistry using magnetic resonance imaging

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    The drive to develop better electrochemical energy storage devices requires the development of not only new materials, but also better understanding of the underpinning chemical and dynamical processes within such devices during operation, for which new analytical techniques are required. Currently, there are few techniques that can probe local composition and transport in the electrolyte during battery operation. In this paper, we report a novel application of magnetic resonance imaging (MRI) for probing electrochemical processes in a model electrochemical cell. Using MRI, the transport and zinc and oxygen electrochemistry in an alkaline electrolyte, typical of that found in zinc-air batteries, are investigated. Magnetic resonance relaxation maps of the electrolyte are used to visualize the chemical composition and electrochemical processes occurring during discharge in this model metal-air battery. Such experiments will be useful in the development of new energy storage/conversion devices, as well as other electrochemical technologies

    Causes of death and demographic characteristics of victims of meteorological disasters in Korea from 1990 to 2008

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    <p>Abstract</p> <p>Background</p> <p>Meteorological disasters are an important component when considering climate change issues that impact morbidity and mortality rates. However, there are few epidemiological studies assessing the causes and characteristics of deaths from meteorological disasters. The present study aimed to analyze the causes of death associated with meteorological disasters in Korea, as well as demographic and geographic vulnerabilities and their changing trends, to establish effective measures for the adaptation to meteorological disasters.</p> <p>Methods</p> <p>Deaths associated with meteorological disasters were examined from 2,045 cases in Victim Survey Reports prepared by 16 local governments from 1990 to 2008. Specific causes of death were categorized as drowning, structural collapse, electrocution, lightning, fall, collision, landslide, avalanche, deterioration of disease by disaster, and others. Death rates were analyzed according to the meteorological type, specific causes of death, and demographic and geographic characteristics.</p> <p>Results</p> <p>Drowning (60.3%) caused the greatest number of deaths in total, followed by landslide (19.7%) and structural collapse (10.1%). However, the causes of deaths differed between disaster types. The meteorological disaster associated with the greatest number of deaths has changed from flood to typhoon. Factors that raised vulnerability included living in coastal provinces (11.3 times higher than inland metropolitan), male gender (1.9 times higher than female), and older age.</p> <p>Conclusions</p> <p>Epidemiological analyses of the causes of death and vulnerability associated with meteorological disasters can provide the necessary information for establishing future adaptation measures against climate change. A more comprehensive system for assessing disaster epidemiology needs to be established.</p

    Nitrogen doping into titanium dioxide by the sol–gel method using nitric acid

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    N-doped TiO(2) has been prepared by use of sol-gel systems containing titanium alkoxide, with nitric acid as the nitrogen source. The time needed for gelation of the systems was drastically reduced by ultrasonic irradiation. The peaks assigned to the nitrate and nitrous ions were observed by FT-IR measurement during the sol-gel reaction. The N-doping was confirmed by the observation of N-O peaks in the XPS spectrum of the sample heated at 400 A degrees C. The nitrate ion acted as an oxidizer of the ethanol solvent and titanium species. The TiO(2) became doped with nitrogen oxide species as a result of reduction of nitrate ion incorporated into the dried gel samples. These results indicated that the added nitric acid was reduced during the sol-gel transition and heating process, and the resulting NO species were situated in the titania networks. The UV and visible photocatalytic activity of the samples was confirmed by the degradation of trichloroethylene.ArticleRESEARCH ON CHEMICAL INTERMEDIATES. 37(8):869-881 (2011)journal articl

    Expansion of social protection is necessary towards zero catastrophic costs due to TB: The first national TB patient cost survey in the Philippines.

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    BACKGROUND: Tuberculosis (TB) is a disease associated with poverty. Moreover, a significant proportion of TB patients face a substantial financial burden before and during TB care. One of the top targets in the End TB strategy was to achieve zero catastrophic costs due to TB by 2020. To assess patient costs related to TB care and the proportion of TB-affected households that faced catastrophic costs, the Philippines National TB Programme (NTP) conducted a national TB patient cost survey in 2016-2017. METHODS: A cross-sectional survey of 1,912 TB patients taking treatment in health facilities engaged with the NTP. The sample consists of 786 drug-sensitive TB (DS-TB) patients in urban facilities, 806 DS-TB patients in rural facilities, and 320 drug-resistant TB (DR-TB) patients. Catastrophic cost due to TB is defined as total costs, consisting of direct medical and non-medical costs and indirect costs net of social assistance, exceeding 20% of annual household income. RESULTS: The overall mean total cost including pre- and post-diagnostic costs was US$601. The mean total cost was five times higher among DR-TB patients than DS-TB patients. Direct non-medical costs and income loss accounted for 42.7% and 40.4% of the total cost of TB, respectively. More than 40% of households had to rely on dissaving, taking loans, or selling their assets to cope with the costs. Overall, 42.4% (95% confidence interval (95% CI): 40.2-44.6) of TB-affected households faced catastrophic costs due to TB, and it was significantly higher among DR-TB patients (89.7%, 95%CI: 86.3-93.0). A TB enabler package, which 70% of DR-TB patients received, reduced catastrophic costs by 13.1 percentage points (89.7% to 76.6%) among DR-TB patients, but only by 0.4 percentage points (42.4% to 42.0%), overall. CONCLUSIONS: TB patients in the Philippines face a substantial financial burden due to TB despite free TB services provided by the National TB Programme. The TB enabler package mitigated catastrophic costs to some extent, but only for DR-TB patients. Enhancing the current social and welfare support through multisectoral collaboration is urgently required to achieve zero catastrophic costs due to TB

    A Host Small GTP-binding Protein ARL8 Plays Crucial Roles in Tobamovirus RNA Replication

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    Tomato mosaic virus (ToMV), like other eukaryotic positive-strand RNA viruses, replicates its genomic RNA in replication complexes formed on intracellular membranes. Previous studies showed that a host seven-pass transmembrane protein TOM1 is necessary for efficient ToMV multiplication. Here, we show that a small GTP-binding protein ARL8, along with TOM1, is co-purified with a FLAG epitope-tagged ToMV 180K replication protein from solubilized membranes of ToMV-infected tobacco (Nicotiana tabacum) cells. When solubilized membranes of ToMV-infected tobacco cells that expressed FLAG-tagged ARL8 were subjected to immunopurification with anti-FLAG antibody, ToMV 130K and 180K replication proteins and TOM1 were co-purified and the purified fraction showed RNA-dependent RNA polymerase activity that transcribed ToMV RNA. From uninfected cells, TOM1 co-purified with FLAG-tagged ARL8 less efficiently, suggesting that a complex containing ToMV replication proteins, TOM1, and ARL8 are formed on membranes in infected cells. In Arabidopsis thaliana, ARL8 consists of four family members. Simultaneous mutations in two specific ARL8 genes completely inhibited tobamovirus multiplication. In an in vitro ToMV RNA translation-replication system, the lack of either TOM1 or ARL8 proteins inhibited the production of replicative-form RNA, indicating that TOM1 and ARL8 are required for efficient negative-strand RNA synthesis. When ToMV 130K protein was co-expressed with TOM1 and ARL8 in yeast, RNA 5′-capping activity was detected in the membrane fraction. This activity was undetectable or very weak when the 130K protein was expressed alone or with either TOM1 or ARL8. Taken together, these results suggest that TOM1 and ARL8 are components of ToMV RNA replication complexes and play crucial roles in a process toward activation of the replication proteins' RNA synthesizing and capping functions

    Transcriptomic comparison of the retina in two mouse models of diabetes

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    Mouse models of type I diabetes offer the potential to combine genetic approaches with other pharmacological or physiological manipulations to investigate the pathophysiology and treatment of diabetic retinopathy. Type I diabetes is induced in mice through chemical toxins or can arise spontaneously from genetic mutations. Both models are associated with retinal vascular and neuronal changes. Retinal transcriptomic responses in C57BL/6J mice treated with streptozotocin and Ins2Akita/+ were compared after 3 months of hyperglycemia. Specific gene expression changes suggest a neurovascular inflammatory response in diabetic retinopathy. Genes common to the two models may represent the response of the retina to hyperglycemia, while changes unique to each model may represent time-dependent disease progression differences in the various models. Further investigation of the commonalities and differences between mouse models of type I diabetes may define cause and effect events in early diabetic retinopathy disease progression

    Management of latent Mycobacterium tuberculosis infection: WHO guidelines for low tuberculosis burden countries

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    Latent tuberculosis infection (LTBI) is characterised by the presence of immune responses to previously acquired Mycobacterium tuberculosis infection without clinical evidence of active tuberculosis (TB). Here we report evidence-based guidelines from the World Health Organization for a public health approach to the management of LTBI in high risk individuals in countries with high or middle upper income and TB incidence of <100 per 100 000 per year. The guidelines strongly recommend systematic testing and treatment of LTBI in people living with HIV, adult and child contacts of pulmonary TB cases, patients initiating anti-tumour necrosis factor treatment, patients receiving dialysis, patients preparing for organ or haematological transplantation, and patients with silicosis. In prisoners, healthcare workers, immigrants from high TB burden countries, homeless persons and illicit drug users, systematic testing and treatment of LTBI is conditionally recommended, according to TB epidemiology and resource availability. Either commercial interferon-gamma release assays or Mantoux tuberculin skin testing could be used to test for LTBI. Chest radiography should be performed before LTBI treatment to rule out active TB disease. Recommended treatment regimens for LTBI include: 6 or 9 month isoniazid; 12 week rifapentine plus isoniazid; 3–4 month isoniazid plus rifampicin; or 3–4 month rifampicin alone

    Social Participation and Disaster Risk Reduction Behaviors in Tsunami Prone Areas

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    This paper examines the relationships between social participation and disaster risk reduction actions. A survey of 557 households in tsunami prone areas in Phang Nga, Thailand was conducted following the 2012 Indian Ocean earthquakes. We use a multivariate probit model to jointly estimate the likelihood of undertaking three responses to earthquake and tsunami hazards (namely, (1) following disaster-related news closely, (2) preparing emergency kits and/or having a family emergency plan, and (3) having an intention to migrate) and community participation.We find that those who experienced losses from the 2004 tsunami are more likely to participate in community activities and respond to earthquake hazards. Compared to men, women are more likely to prepare emergency kits and/or have an emergency plan and have a greater intention to migrate. Living in a community with a higher proportion of women with tertiary education increases the probability of engaging in community activities and carrying out disaster risk reduction measures. Individuals who participate in village-based activities are 5.2% more likely to undertake all three risk reduction actions compared to those not engaging in community activities. This implies that encouraging participation in community activities can have positive externalities in disaster mitigation
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