214 research outputs found

    Halide binding by the purified halorhodopsin chromoprotein. II. New chloride-binding sites revealed by 35Cl NMR

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    Halorhodopsin is a light-driven chloride pump in the cell membrane of Halobacterium halobium. Recently, a polypeptide of apparent Mr = 20,000 has been purified that contains the halorhodopsin chromophore. Here we use 35Cl NMR to show that the purified chromoprotein possesses two previously unknown classes of chloride-binding sites. One class exhibits a low affinity (KD much greater than 1 M) for chloride and bromide. The second class exhibits a higher affinity (KD = 110 ± 50 mM) for chloride and also binds other anions according to the affinity series I-, SCN- greater than Br-, NO-3 greater than Cl- greater than F- , citrate. Both classes of NMR site remain intact at pH 11, indicating that the essential positive charges are provided by arginine. Also, both classes are unaffected by bleaching, suggesting that the sites are not in the immediate vicinity of the halorhodopsin chromophore. Although the chromoprotein also appears to contain the chloride- transport site (Steiner, M., Oesterhelt, D., Ariki, M., and Lanyi, J. K. (1984) J. Biol. Chem. 259, 2179-2184), this site was not detected by 35Cl NMR, suggesting that the transport site is in the interior of the protein where it is sampled slowly by chloride in the medium. It is proposed that the purified chromoprotein possesses a channel leading from the medium to the transport site and that the channel contains the high affinity NMR site which facilitates the migration of chloride between the medium and the transport site. We have also used 35Cl NMR to study chloride binding to purified monomeric bacteriorhodopsin; however, this protein contains no detectable chloride-binding sites

    What's the best treatment for cradle cap?

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    Ketoconazole (Nizoral) shampoo appears to be a safe and efficacious treatment for infants with cradle cap (strength of recommendation [SOR]: C, consensus, usual practice, opinion, disease-oriented evidence, and case series). Limit topical corticosteroids to severe cases because of possible systemic absorption (SOR: C). Overnight application of emollients followed by gentle brushing and washing with baby shampoo helps to remove the scale associated with cradle cap (SOR: C)

    The Evaluation of V_{ud}, Experiment and Theory

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    The value of the V_{ud} matrix element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be derived from nuclear superallowed beta decays, neutron decay, and pion beta decay. We survey current world data for all three. Today, the most precise value of V_{ud} comes from the nuclear decays; however, the precision is limited not by experimental error but by the estimated uncertainty in theoretical corrections. Experimental uncertainty does limit the neutron-decay result, which, though statistically consistent with the nuclear result, is approximately a factor of three poorer in precision. The value obtained for VudV_{ud} leads to a result that differs at the 98% confidence level from the unitarity condition for the CKM matrix. We examine the reliability of the small calculated corrections that have been applied to the data, and assess the likelihood of even higher quality nuclear data becoming available to confirm or deny the discrepancy. Some of the required experiments depend upon the availability of intense radioactive beams. Others are possible today.Comment: 21 pages, 1 figure, LaTe

    Live Robot Sensor View

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    The Valparaiso University Robotics Team\u27s Robotic Football group has requested an application to process and display real-time sensor data during gameplay. Data of interest to both the build and drive teams includes the robot\u27s uptime, current speed, motor power, control stick orientation, and battery life. This information will be sent to a Raspberry Pi single-board system by Arduino chips on each robot via MQTT and processed and presented by the application being built. To achieve this, the tool will be built on the Django web server framework, using Python. Challenges involve working with multiple stakeholders, multiple networked objects sending data simultaneously, and rapidly-evolving technical considerations

    Live Robot Sensor View

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    The Valparaiso University Robotics Team\u27s Robotic Football group has requested an application to process and display real-time sensor data during gameplay. Data of interest to both the build and drive teams includes the robot\u27s uptime, current speed, motor power, control stick orientation, and battery life. This information will be sent to a Raspberry Pi single-board system by Arduino chips on each robot via MQTT and processed and presented by the application being built. To achieve this, the tool will be built on the Django web server framework, using Python. Challenges involve working with multiple stakeholders, multiple networked objects sending data simultaneously, and rapidly-evolving technical considerations

    Epidemiology of unintentional child injuries in the makwanpur district of Nepal: A household survey

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    © 2015 by the authors; licensee MDPI, Basel, Switzerland. Secondary sources of information indicate that the proportion of child deaths due to injuries is increasing in Nepal. This study aimed to describe the epidemiology of unintentional injuries in children, explore risk factors and estimate the burden faced by families and the community in the Makwanpur district. We conducted a household survey in Makwanpur, covering 3441 households. Injuries that occurred during the 12 months before the survey and required treatment or caused the child to be unable to take part in usual activities for three or more days were included. We identified 193 cases of non-fatal unintentional child injuries from 181 households and estimated an annual rate of non-fatal injuries of 24.6/1000 children; rates for boys were double (32.7/1000) that for girls (16.8/1000). The rates were higher among the children of age groups 1–4 years and 5–9 years. Falls were the most common cause of non-fatal child injuries followed by burns in preschool children and road traffic injuries were the most likely cause in adolescence. Mean period of disability following injury was 25 days. The rates and the mechanisms of injury vary by age and gender. Falls and burns are currently the most common mechanisms of injury amongst young children around rural homes

    The Puzzle of Neutron Lifetime

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    In this paper we review the role of the neutron lifetime and discuss the present status of measurements. In view of the large discrepancy observed by the two most precise individual measurements so far we describe the different techniques and point out principle strengths and weaknesses. In particular we discuss the estimation of systematic uncertainties and its correlation to the statistical ones. In order to solve the present puzzle, many new experiments are either ongoing or being proposed. An overview on their possible contribution to this field will be given.Comment: 10 pages, 19 figures, Proceedings of the International Workshop on Particle Physics with Slow Neutron

    Marburg Virus Infection Detected in a Common African Bat

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    Marburg and Ebola viruses can cause large hemorrhagic fever (HF) outbreaks with high case fatality (80–90%) in human and great apes. Identification of the natural reservoir of these viruses is one of the most important topics in this field and a fundamental key to understanding their natural history. Despite the discovery of this virus family almost 40 years ago, the search for the natural reservoir of these lethal pathogens remains an enigma despite numerous ecological studies. Here, we report the discovery of Marburg virus in a common species of fruit bat (Rousettus aegyptiacus) in Gabon as shown by finding virus-specific RNA and IgG antibody in individual bats. These Marburg virus positive bats represent the first naturally infected non-primate animals identified. Furthermore, this is the first report of Marburg virus being present in this area of Africa, thus extending the known range of the virus. These data imply that more areas are at risk for MHF outbreaks than previously realized and correspond well with a recently published report in which three species of fruit bats were demonstrated to be likely reservoirs for Ebola virus

    Large serological survey showing cocirculation of Ebola and Marburg viruses in Gabonese bat populations, and a high seroprevalence of both viruses in Rousettus aegyptiacus

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    <p>Abstract</p> <p>Background</p> <p>Ebola and Marburg viruses cause highly lethal hemorrhagic fevers in humans. Recently, bats of multiple species have been identified as possible natural hosts of <it>Zaire ebolavirus </it>(ZEBOV) in Gabon and Republic of Congo, and also of <it>marburgvirus </it>(MARV) in Gabon and Democratic Republic of Congo.</p> <p>Methods</p> <p>We tested 2147 bats belonging to at least nine species sampled between 2003 and 2008 in three regions of Gabon and in the Ebola epidemic region of north Congo for IgG antibodies specific for ZEBOV and MARV.</p> <p>Results</p> <p>Overall, IgG antibodies to ZEBOV and MARV were found in 4% and 1% of bats, respectively. ZEBOV-specific antibodies were found in six bat species (<it>Epomops franqueti, Hypsignathus monstrosus, Myonycteris torquata, Micropteropus pusillus, Mops condylurus </it>and <it>Rousettus aegyptiacus</it>), while MARV-specific antibodies were only found in <it>Rousettus aegyptiacus </it>and <it>Hypsignathus monstrosus</it>. The prevalence of MARV-specific IgG was significantly higher in <it>R. aegyptiacus </it>members captured inside caves than elsewhere. No significant difference in prevalence was found according to age or gender. A higher prevalence of ZEBOV-specific IgG was found in pregnant females than in non pregnant females.</p> <p>Conclusion</p> <p>These findings confirm that ZEBOV and MARV co-circulate in Gabon, the only country where bats infected by each virus have been found. IgG antibodies to both viruses were detected only in <it>Rousettus aegyptiacus</it>, suggesting that this bat species may be involved in the natural cycle of both Marburg and Ebola viruses. The presence of MARV in Gabon indicates a potential risk for a first human outbreak. Disease surveillance should be enhanced in areas near caves.</p
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