357 research outputs found
The efficacy of periodic +Gz exposure in the prevention of bedrest induced orthostatic intolerance
What is the most efficient dosage of periodic exposure to positive 1G(z) during microgravity to maintain a functional upright position after returning to a positive 1G(z) environment? The answer has implications for the type of countermeasures astronauts will be required to perform during long term space flight. Methods: Nine males were subjected to four different positive 1G exposure protocols plus a control protocol ('zero G(z)') during four days of continuous bedrest. The four positive 1G(z) exposures consisted of periodic standing or walking, each for a total period of two or four hours. Each subject was returned for bedrest on five different occasions over a period of approximately one year to obtain data on each of the nine subjects across all four positive 1G(z) treatments and the control. A 30 min tilt test was used to measure orthostatic response during pre and post bedrest. Results: In terms of survival rate (percentage of subjects who did not faint after 30 sec of tilt), four hours of intermittent standing was the only protocol that maintained a rate comparable to pre bedrest levels (87.5 percent). Although the other three positive 1G(z) protocols performed better than the 'zero G(z) control (22.2 percent), only the four hour standing returned post bedrest survival rates to pre bedrest levels. Conclusions: The results will need to be evaluated with regards to a variety of other physiological systems which are known to decondition during microgravitry
Dépistage du cancer anal : doit-on faire de même que pour le cancer du col utérin ? [Screening for anal cancer : is it the same as for cervical cancer ?]
Anal dysplasia is usually caused by HPV infection and can lead to squamous anal cancer. The purpose of this article is to describe the classification of these precursor lesions but above all to identify the groups of patients at risk and to clarify the screening and follow-up that must be initiated
Isoprene photochemistry over the Amazon rainforest
Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO_2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK + MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK + MACR spanned 0.4–0.6. This result implies a ratio of the reaction rate of ISOPOO with HO_2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). This abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest
Awareness of vaccination status and its predictors among working people in Switzerland
BACKGROUND: Adult vaccination status may be difficult to obtain, often requiring providers to rely on individual patient recall. To determine vaccination status awareness and the sociodemographic predictors of awareness for tetanus, hepatitis A and B, tick born encephalitis (TBE) and influenza vaccination. METHODS: Multivariate analyses were used to evaluate a questionnaire survey of 10 321 employees (4070 women and 6251 men aged 15–72 years) of two companies in Switzerland. RESULTS: Among 10 321 respondents, 75.5% reported knowing their tetanus vaccination status, 64.1% hepatitis A, 61.1% hepatitis B, 64.3% TBE and 71.9% influenza. Between 1 in 4 and 1 in 3 employees were not aware of their vaccination status. Differences in awareness for the five vaccinations considered correlated with gender and language. These differences persisted in multivariate analyses. CONCLUSION: Women employees, German-speaking employees and employees who paid more attention to their diet were more often aware of their vaccination status. A more reliable and readily accessible data source for vaccination status is needed in order to capitalize on opportunities to update vaccinations among Swiss employees
Potential application in biocatalysis of mycelium-bound lipases from Amazonian fungi
In this study, 212 fungi were isolated from Amazon region plants, aiming to obtain mycelium bound-lipase-producing biocatalysts. These isolates were submitted to hydrolytic and synthetic activity assays. When submitted to the tributyrine substrate test, 87% of the isolates showed hydrolytic activity. Of these, 30% showed good growth in lipase inducing liquid media and were submitted to evaluation of synthetic activity in esterification and transesterification reactions in organic solvents. The nine fungi which had the best synthetic activity were evaluated in the (R, S)-2-octanol resolution reaction, in order to verify the enantioselectivity of mycelium-bound lipases. The isolate UEA_115 was the most versatile biocatalyst, showing good performance in esterification reactions (conversion > 90%) and good ability for the resolution of (R, S)-2-octanol (ee s 29%; ee p 99%; c 22%; E > 200). Thus, this study has demonstrated the great potential of the Amazonian fungi as lipase suppliers for biocatalysts
Multi-locus genome-wide association analysis supports the role of glutamatergic synaptic transmission in the etiology of major depressive disorder
Major depressive disorder (MDD) is a common psychiatric illness characterized by low mood and loss of interest in pleasurable activities. Despite years of effort, recent genome-wide association studies (GWAS) have identified few susceptibility variants or genes that are robustly associated with MDD. Standard single-SNP (single nucleotide polymorphism)-based GWAS analysis typically has limited power to deal with the extensive heterogeneity and substantial polygenic contribution of individually weak genetic effects underlying the pathogenesis of MDD. Here, we report an alternative, gene-set-based association analysis of MDD in an effort to identify groups of biologically related genetic variants that are involved in the same molecular function or cellular processes and exhibit a significant level of aggregated association with MDD. In particular, we used a text-mining-based data analysis to prioritize candidate gene sets implicated in MDD and conducted a multi-locus association analysis to look for enriched signals of nominally associated MDD susceptibility loci within each of the gene sets. Our primary analysis is based on the meta-analysis of three large MDD GWAS data sets (total N = 4346 cases and 4430 controls). After correction for multiple testing, we found that genes involved in glutamatergic synaptic neurotransmission were significantly associated with MDD (set-based association P = 6.9 X 10(-4)). This result is consistent with previous studies that support a role of the glutamatergic system in synaptic plasticity and MDD and support the potential utility of targeting glutamatergic neurotransmission in the treatment of MDD
Localization of metabotropic glutamate receptors in the outer plexiform layer of the goldfish retina
We studied the localization of metabotropic glutamate receptors (mGluRs) in the goldfish outer plexiform layer by light-and electron-microscopical immunohistochemistry. The mGluR1α antibody labeled putative ON-type bipolar cell dendrites and horizontal cell processes in both rod spherules and cone triads. Immunolabeling for mGluR2/3 was absent in the rod synaptic complex but was found at horizontal cell dendrites directly opposing the cone synaptic ribbon. The mGluR5 antibody labeled Müller cell processes wrapping rod terminals and horizontal cell somata. The mGluR7 antibody labeled mainly horizontal cell dendrites invaginating rods and cones and some putative bipolar cell dendrites in the cone synaptic complex. The finding of abundant expression of various mGluRs in bipolar and horizontal cell dendrites suggests multiple sites of glutamatergic modulation in the outer retina
Genetic Dissection of Strain Dependent Paraquat-induced Neurodegeneration in the Substantia Nigra Pars Compacta
The etiology of the vast majority of Parkinson's disease (PD) cases is unknown. It is generally accepted that there is an interaction between exposures to environmental agents with underlying genetic sensitivity. Recent epidemiological studies have shown that people living in agricultural communities have an increased risk of PD. Within these communities, paraquat (PQ) is one of the most utilized herbicides. PQ acts as a direct redox cycling agent to induce formation of free radicals and when administered to mice induces the cardinal symptoms of parkinsonism, including loss of TH+-positive dopaminergic (DA) neurons in the ventral midbrain's substantia nigra pars compacta (SNpc). Here we show that PQ-induced SNpc neuron loss is highly dependent on genetic background: C57BL/6J mice rapidly lose ∼50% of their SNpc DA neurons, whereas inbred Swiss-Webster (SWR/J) mice do not show any significant loss. We intercrossed these two strains to map quantitative trait loci (QTLs) that underlie PQ-induced SNpc neuron loss. Using genome-wide linkage analysis we detected two significant QTLs. The first is located on chromosome 5 (Chr 5) centered near D5Mit338, whereas the second is on Chr 14 centered near D14Mit206. These two QTLs map to different loci than a previously identified QTL (Mptp1) that controls a significant portion of strain sensitivity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), suggesting that the mechanism of action of these two parkinsonian neurotoxins are different
Isoprene photochemistry over the Amazon rainforest
Isoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacrolein (MACR). Unimolecular isomerization and bimolecular reactions with organic peroxy radicals are also possible. There is uncertainty about the relative importance of each of these pathways in the atmosphere and possible changes because of anthropogenic pollution. Herein, measurements of ISOPOOH and MVK+MACR concentrations are reported over the central region of the Amazon basin during the wet season. The research site, downwind of an urban region, intercepted both background and polluted air masses during the GoAmazon2014/5 Experiment. Under background conditions, the confidence interval for the ratio of the ISOPOOH concentration to that of MVK+MACR spanned 0.4-0.6. This result implies a ratio of the reaction rate of ISOPOO with HO2 to that with NO of approximately unity. A value of unity is significantly smaller than simulated at present by global chemical transport models for this important, nominally low-NO, forested region of Earth. Under polluted conditions, when the concentrations of reactive nitrogen compounds were high (>1 ppb), ISOPOOH concentrations dropped below the instrumental detection limit (<60 ppt). This abrupt shift in isoprene photooxidation, sparked by human activities, speaks to ongoing and possible future changes in the photochemistry active over the Amazon rainforest
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Intermediate-scale horizontal isoprene concentrations in the near-canopy forest atmosphere and implications for emission heterogeneity
The emissions, deposition, and chemistry of volatile organic compounds (VOCs) are thought to be influenced by underlying landscape heterogeneity at intermediate horizontal scales of several hundred meters across different forest subtypes within a tropical forest. Quantitative observations and scientific understanding at these scales, however, remain lacking, in large part due to a historical absence of canopy access and suitable observational approaches. Herein, horizontal heterogeneity in VOC concentrations in the nearcanopy atmosphere was examined by sampling from an unmanned aerial vehicle (UAV) flown horizontally several hundred meters over the plateau and slope forests in central Amazonia during the morning and early afternoon periods of the wet season of 2018. Unlike terpene concentrations, the isoprene concentrations in the near-canopy atmosphere over the plateau forest were 60% greater than those over the slope forest. A gradient transport model constrained by the data suggests that isoprene emissions differed by 220 to 330%from these forest subtypes, which is in contrast to a 0% difference implemented in most present-day biosphere emissions models (i.e., homogeneous emissions). Quantifying VOC concentrations, emissions, and other processes at intermediate horizontal scales is essential for understanding the ecological and Earth system roles of VOCs and representing them in climate and air quality models. © 2019 National Academy of Sciences. All rights reserved
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