807 research outputs found
Benzolamide improves oxygenation and reduces acute mountain sickness during a high-altitude trek and has fewer side effects than acetazolamide at sea level.
Acetazolamide is the standard carbonic anhydrase (CA) inhibitor used for acute mountain sickness (AMS), however some of its undesirable effects are related to intracellular penetrance into many tissues, including across the blood-brain barrier. Benzolamide is a much more hydrophilic inhibitor, which nonetheless retains a strong renal action to engender a metabolic acidosis and ventilatory stimulus that improves oxygenation at high altitude and reduces AMS. We tested the effectiveness of benzolamide versus placebo in a first field study of the drug as prophylaxis for AMS during an ascent to the Everest Base Camp (5340 m). In two other studies performed at sea level to test side effect differences between acetazolamide and benzolamide, we assessed physiological actions and psychomotor side effects of two doses of acetazolamide (250 and 1000 mg) in one group of healthy subjects and in another group compared acetazolamide (500 mg), benzolamide (200 mg) and lorazepam (2 mg) as an active comparator for central nervous system (CNS) effects. At high altitude, benzolamide-treated subjects maintained better arterial oxygenation at all altitudes (3-6% higher at all altitudes above 4200 m) than placebo-treated subjects and reduced AMS severity by roughly 50%. We found benzolamide had fewer side effects, some of which are symptoms of AMS, than any of the acetazolamide doses in Studies 1 and 2, but equal physiological effects on renal function. The psychomotor side effects of acetazolamide were dose dependent. We conclude that benzolamide is very effective for AMS prophylaxis. With its lesser CNS effects, benzolamide may be superior to acetazolamide, in part, because some of the side effects of acetazolamide may contribute to and be mistaken for AMS
Purifying Selection in Deeply Conserved Human Enhancers Is More Consistent than in Coding Sequences
(c) 2014 De Silva et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Observation of Coherent Elastic Neutrino-Nucleus Scattering
The coherent elastic scattering of neutrinos off nuclei has eluded detection
for four decades, even though its predicted cross-section is the largest by far
of all low-energy neutrino couplings. This mode of interaction provides new
opportunities to study neutrino properties, and leads to a miniaturization of
detector size, with potential technological applications. We observe this
process at a 6.7-sigma confidence level, using a low-background, 14.6-kg
CsI[Na] scintillator exposed to the neutrino emissions from the Spallation
Neutron Source (SNS) at Oak Ridge National Laboratory. Characteristic
signatures in energy and time, predicted by the Standard Model for this
process, are observed in high signal-to-background conditions. Improved
constraints on non-standard neutrino interactions with quarks are derived from
this initial dataset
Next-generation mitogenomics: A comparison of approaches applied to caecilian amphibian phylogeny
Mitochondrial genome (mitogenome) sequences are being generated with increasing speed due to the advances of next-generation sequencing (NGS) technology and associated analytical tools. However, detailed comparisons to explore the utility of alternative NGS approaches applied to the same taxa have not been undertaken. We compared a 'traditional' Sanger sequencing method with two NGS approaches (shotgun sequencing and non-indexed, multiplex amplicon sequencing) on four different sequencing platforms (Illumina's HiSeq and MiSeq, Roche's 454 GS FLX, and Life Technologies' Ion Torrent) to produce seven (near-) complete mitogenomes from six species that form a small radiation of caecilian amphibians from the Seychelles. The fastest, most accurate method of obtaining mitogenome sequences that we tested was direct sequencing of genomic DNA (shotgun sequencing) using the MiSeq platform. Bayesian inference and maximum likelihood analyses using seven different partitioning strategies were unable to resolve compellingly all phylogenetic relationships among the Seychelles caecilian species, indicating the need for additional data in this case
The effectiveness of mindfulness-based interventions in the perinatal period: a systematic review and meta-analysis
Perinatal mental health difficulties are associated with adverse consequences for parents and infants. However, the potential risks associated with the use of psychotropic medication for pregnant and breastfeeding women and the preferences expressed by women for non-pharmacological interventions mean it is important to ensure that effective psychological interventions are available. It has been argued that mindfulness-based interventions may offer a novel approach to treating perinatal mental health difficulties, but relatively little is known about their effectiveness with perinatal populations. This paper therefore presents a systematic review and meta-analysis of the effectiveness of mindfulness-based interventions for reducing depression, anxiety and stress and improving mindfulness skills in the perinatal period. A systematic review identified seventeen studies of mindfulness-based interventions in the perinatal period, including both controlled trials (n = 9) and pre-post uncontrolled studies (n = 8). Eight of these studies also included qualitative data. Hedge’s g was used to assess uncontrolled and controlled effect sizes in separate meta-analyses, and a narrative synthesis of qualitative data was produced. Pre- to post-analyses showed significant reductions in depression, anxiety and stress and significant increases in mindfulness skills post intervention, each with small to medium effect sizes. Completion of the mindfulness-based interventions was reasonable with around three quarters of participants meeting study-defined criteria for engagement or completion where this was recorded. Qualitative data suggested that participants viewed mindfulness interventions positively. However, between-group analyses failed to find any significant post-intervention benefits for depression, anxiety or stress of mindfulness-based interventions in comparison to control conditions: effect sizes were negligible and it was conspicuous that intervention group participants did not appear to improve significantly more than controls in their mindfulness skills. The interventions offered often deviated from traditional mindfulness-based cognitive therapy or mindfulness-based stress reduction programmes, and there was also a tendency for studies to focus on healthy rather than clinical populations, and on antenatal rather than postnatal populations. It is argued that these and other limitations with the included studies and their interventions may have been partly responsible for the lack of significant between-group effects. The implications of the findings and recommendations for future research are discussed
Global-scale evidence for the refractory nature of riverine black carbon
Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Nature Geoscience 11 (2018): 584-588, doi:10.1038/s41561-018-0159-8.Wildfires and incomplete combustion of fossil fuel produce large amounts of black carbon. Black carbon production and transport are essential components of the carbon cycle. Constraining estimates of black carbon exported from land to ocean is critical, given ongoing changes in land use and climate, which affect fire occurrence and black carbon dynamics. Here, we present an inventory of the concentration and radiocarbon content (∆14C) of particulate black carbon for 18 rivers around the globe. We find that particulate black carbon accounts for about 15.8 ± 0.9% of river particulate organic carbon, and that fluxes of particulate black carbon co-vary with river-suspended sediment, indicating that particulate black carbon export is primarily controlled by erosion. River particulate black carbon is not exclusively from modern sources but is also aged in intermediate terrestrial carbon pools in several high-latitude rivers, with ages of up to 17,000 14C years. The flux-weighted 14C average age of particulate black carbon exported to oceans is 3,700 ± 400 14C years. We estimate that the annual global flux of particulate black carbon to the ocean is 0.017 to 0.037 Pg, accounting for 4 to 32% of the annually produced black carbon. When buried in marine sediments, particulate black carbon is sequestered to form a long-term sink for CO2.A.C. acknowledges financial support from the University of Zurich Forschungskredit Fellowship and the University of Zurich (grant No. STWF-18-026). M.R., S.A. and M.S. acknowledge support from the University Research Priority Projection Global Change and Biodiversity (URPP-GCB). M.Z. acknowledges support from the National Natural Science Foundation of China (No. 41521064). T.E. acknowledges support from the Swiss National Science Foundation (“CAPS-LOCK” and “CAPS-LOCK2” #200021_140850). V.G. acknowledges financial support from an Independent Study Award from the Woods Hole Oceanographic Institution
Effects of nutrient addition and soil drainage on germination of N-fixing and non-N-fixing tropical dry forest tree species
To develop generalised predictions regarding the effects of atmospheric nitrogen (N) and phosphorus (P) deposition on vegetation communities, it is necessary to account for the impacts of increased nutrient availability on the early life history stages of plants. Additionally, it is important to determine if these responses (a) differ between plant functional groups and (b) are modulated by soil drainage, which may affect the persistence of added nutrients. We experimentally assessed seed germination responses (germination proportion and germination energy, i.e. time to germination) of commonly occurring N-fixing and non-N-fixing tropical dry forest tree species found in India to simulated N and P deposition in well-drained soils, as well as soils with impeded drainage. When soils were not allowed to drain, germination proportion declined with nutrient addition, while germination energy remained unchanged. Stronger declines in germination proportion were observed for N-fixing species. In free-draining soils, nutrient addition did not affect germination proportion in either functional group. However, we detected a trend of delayed germination with nutrient addition, especially in N-fixers. Our results suggest that nutrient deposition can lead to potential shifts in functional dominance and tree community composition of tropical dry forests in the long term through its effects on early life stages of trees, although the mechanisms underlying the observed germination responses remain unclear. Further, such effects are likely to be spatially variable across the geographic range in which tropical dry forests occur depending on soil drainage properties
Nitrate Reduction Functional Genes and Nitrate Reduction Potentials Persist in Deeper Estuarine Sediments. Why?
Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are processes occurring simultaneously under oxygen-limited or anaerobic conditions, where both compete for nitrate and organic carbon. Despite their ecological importance, there has been little investigation of how denitrification and DNRA potentials and related functional genes vary vertically with sediment depth. Nitrate reduction potentials measured in sediment depth profiles along the Colne estuary were in the upper range of nitrate reduction rates reported from other sediments and showed the existence of strong decreasing trends both with increasing depth and along the estuary. Denitrification potential decreased along the estuary, decreasing more rapidly with depth towards the estuary mouth. In contrast, DNRA potential increased along the estuary. Significant decreases in copy numbers of 16S rRNA and nitrate reducing genes were observed along the estuary and from surface to deeper sediments. Both metabolic potentials and functional genes persisted at sediment depths where porewater nitrate was absent. Transport of nitrate by bioturbation, based on macrofauna distributions, could only account for the upper 10 cm depth of sediment. A several fold higher combined freeze-lysable KCl-extractable nitrate pool compared to porewater nitrate was detected. We hypothesised that his could be attributed to intracellular nitrate pools from nitrate accumulating microorganisms like Thioploca or Beggiatoa. However, pyrosequencing analysis did not detect any such organisms, leaving other bacteria, microbenthic algae, or foraminiferans which have also been shown to accumulate nitrate, as possible candidates. The importance and bioavailability of a KCl-extractable nitrate sediment pool remains to be tested. The significant variation in the vertical pattern and abundance of the various nitrate reducing genes phylotypes reasonably suggests differences in their activity throughout the sediment column. This raises interesting questions as to what the alternative metabolic roles for the various nitrate reductases could be, analogous to the alternative metabolic roles found for nitrite reductases
Early changes within the lymphocyte population are associated with the development of multiple organ dysfunction syndrome in trauma patients
2016 The Author(s). Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.JM was funded, in part, by the Royal College of Surgeons of England, The Phillip King Charitable Trust Research Fellowship and The National Institute of Health Research (NIHR)
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