155 research outputs found

    Regulation of Redox Signaling by Selenoproteins

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    The unique chemistry of oxygen has been both a resource and threat for life on Earth for at least the last 2.4 billion years. Reduction of oxygen to water allows extraction of more metabolic energy from organic fuels than is possible through anaerobic glycolysis. On the other hand, partially reduced oxygen can react indiscriminately with biomolecules to cause genetic damage, disease, and even death. Organisms in all three superkingdoms of life have developed elaborate mechanisms to protect against such oxidative damage and to exploit reactive oxygen species as sensors and signals in myriad processes. The sulfur amino acids, cysteine and methionine, are the main targets of reactive oxygen species in proteins. Oxidative modifications to cysteine and methionine can have profound effects on a protein’s activity, structure, stability, and subcellular localization. Non-reversible oxidative modifications (oxidative damage) may contribute to molecular, cellular, and organismal aging and serve as signals for repair, removal, or programmed cell death. Reversible oxidation events can function as transient signals of physiological status, extracellular environment, nutrient availability, metabolic state, cell cycle phase, immune function, or sensory stimuli. Because of its chemical similarity to sulfur and stronger nucleophilicity and acidity, selenium is an extremely efficient catalyst of reactions between sulfur and oxygen. Most of the biological activity of selenium is due to selenoproteins containing selenocysteine, the 21st genetically encoded protein amino acid. The most abundant selenoproteins in mammals are the glutathione peroxidases (five to six genes) that reduce hydrogen peroxide and lipid hydroperoxides at the expense of glutathione and serve to limit the strength and duration of reactive oxygen signals. Thioredoxin reductases (three genes) use nicotinamide adenine dinucleotide phosphate to reduce oxidized thioredoxin and its homologs, which regulate a plethora of redox signaling events. Methionine sulfoxide reductase B1 reduces methionine sulfoxide back to methionine using thioredoxin as a reductant. Several selenoproteins in the endoplasmic reticulum are involved in the regulation of protein disulfide formation and unfolded protein response signaling, although their precise biological activities have not been determined. The most widely distributed selenoprotein family in Nature is represented by the highly conserved thioredoxin-like selenoprotein W and its homologs that have not yet been assigned specific biological functions. Recent evidence suggests selenoprotein W and the six other small thioredoxin-like mammalian selenoproteins may serve to transduce hydrogen peroxide signals into regulatory disulfide bonds in specific target proteins

    CP violation at BABAR

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    Several new and updated BABAR measurements of sin 2β are presented, together with the latest constraints on the Unitarity Triangle angles α and γ. The higher statistics now available allow more sophisticated analysis techniques, such as time-dependent Dalitz plot fitting. Combined worldaverage results place tight constraints on the Unitarity Triangle. There is good agreement among the measurements and with the unitarity of the CKM matrix. This represents an impressive verification of the Standard Model description of the quark-flavour sector and of CP violation

    Characterization of the Aquistore CO2 project storage site, Saskatchewan, Canada

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    AbstractAquistore is a new integrated Carbon Capture and Storage demonstration project in southeastern Saskatchewan, Canada. An extensive geological, geophysical, petrophysical, hydrogeological, and geochemical characterization program was undertaken using both pre-existing and newly-acquired data at this site. Data were assembled into several geological models that were used to support planning and permitting of the project. Carbon dioxide will be injected into a permeable sandstone interval approximately 150m thick using a newly-drilled 3400m deep injection well and monitored, in part, using a new 3400m deep instrumented observation well that is 150m away from the injection well. All of the integrated characterization work at the site thus far indicates strongly favorable conditions for geological CO2 storage in the subsurface at Aquistore

    Why Men Trophy Hunt

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    The killing of Cecil the lion (Panthera leo) ignited enduring and increasingly global discussion about trophy hunting. Yet, policy debate about its benefits and costs focuses only on the hunted species and biodiversity, not the unique behaviour of hunters. Some contemporary recreational hunters from the developed world behave curiously, commonly targeting ‘trophies’: individuals within populations with large body or ornament size, as well as rare and/or inedible species, like carnivores. Although contemporary hunters have been classified according to implied motivation (i.e. for meat, recreation, trophy or population control, as well the ‘multiple satisfactions’ they seek while hunting (affiliation, appreciation, achievement; an evolutionary explanation of the motivation underlying trophy hunting (and big-game fishing) has never been pursued. Too costly (difficult, dangerous) a behaviour to be common among other vertebrate predators, we postulate that trophy hunting is in fact motivated by the costs hunters accept. We build on empirical and theoretical contributions from evolutionary anthropology to hypothesize that signalling these costs to others is key to understanding, and perhaps influencing, this otherwise perplexing activity

    Beyond Electronics

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    Amundson traces the histories of electronic technologies, video, and electronic art, examining the shift from art about the technology itself to work that uses it as an expressive tool or addresses its social dimension. Lists exhibitions related to art and technology. Statements by 11 artists. Biographical notes. 14 bibl. ref

    Ongoing studies on the bats of Danum Valley Borneo

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    Here we provide an update on the batting activities of the James Cook University's biannual undergraduate field trip to Danum Valley Field Centre in Borneo. The 2013 trip focussed on various bat surveying techniques, with an emphasis on the use and effectiveness of the EM3 full-spectrum and Anabat II ZCAM ultrasonic detectors. We captured a total of thirty-three individuals of 12 different species in harp traps and mist nets, three species of which had not been encountered on previous surveys. We collected an additional 16,500 call files and in total, we now have a call library of 43 microbat species (of which 28 can be allocated to individual species) along with high-quality photographs of 20 micro- and megabats. It will be no surprise that Terry Reardon also took dynamic photographs of individuals in flight upon release, and generously donated his flash-setup to the staff of Danum Valley. Future field trips will continue to build the call and photo library as well as collect tissue samples for collaborative studies with scientists in Malaysia and Australia. We plan to make the calls and photos available via an open-access WWW page

    Epidemiology and outcomes from out-of-hospital cardiac arrests in England

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    Introduction This study reports the epidemiology and outcomes from out-of-hospital cardiac arrest (OHCA) in England during 2014. Methods Prospective observational study from the national OHCA registry. The incidence, demographic and outcomes of patients who were treated for an OHCA between 1st January 2014 and 31st December 2014 in 10 English ambulance service (EMS) regions, serving a population of almost 54 million, are reported in accordance with Utstein recommendations. Results 28,729 OHCA cases of EMS treated cardiac arrests were reported (53 per 100,000 of resident population). The mean age was 68.6 (SD = 19.6) years and 41.3% were female. Most (83%) occurred in a place of residence, 52.7% were witnessed by either the EMS or a bystander. In non-EMS witnessed cases, 55.2% received bystander CPR whilst public access defibrillation was used rarely (2.3%). Cardiac aetiology was the leading cause of cardiac arrest (60.9%). The initial rhythm was asystole in 42.4% of all cases and was shockable (VF or pVT) in 20.6%. Return of spontaneous circulation at hospital transfer was evident in 25.8% (n = 6302) and survival to hospital discharge was 7.9%. Conclusion Cardiac arrest is an important cause of death in England. With less than one in ten patients surviving, there is scope to improve outcomes. Survival rates were highest amongst those who received bystander CPR and public access defibrillation
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