315 research outputs found
Magic angle spinning (MAS) NMR linewidths in the presence of solid-state dynamics
In solid-state NMR, the magic angle spinning (MAS) technique fails to suppress anisotropic spin interactions fully if reorientational dynamics are present, resulting in a decay of the rotational-echo train in the time-domain signal. We show that a simple analytical model can be used to quantify this linebroadening effect as a function of the MAS frequency, reorientational rate constant, and magnitude of the inhomogeneous anisotropic broadening. We compare this model with other theoretical approaches and with exact computer simulations, and show how it may be used to estimate rate constants from experimental NMR data
Electromagnetic follow-up of gravitational wave transient signal candidates
Pioneering efforts aiming at the development of multi-messenger gravitational
wave and electromagnetic astronomy have been made. An electromagnetic
observation follow-up program of candidate gravitational wave events has been
performed (Dec 17 2009 to Jan 8 2010 and Sep 4 to Oct 20 2010) during the
recent runs of the LIGO and Virgo gravitational wave detectors. It involved
ground-based and space electromagnetic facilities observing the sky at optical,
X-ray and radio wavelengths. The joint gravitational wave and electromagnetic
observation study requires the development of specific image analysis
procedures able to discriminate the possible electromagnetic counterpart of
gravitational wave triggers from contaminant/background events. The paper
presents an overview of the electromagnetic follow-up program and the image
analysis procedures.Comment: Proceedings of the 12th International Conference on "Topics in
Astroparticle and Underground Physics" (TAUP 2011), Munich, September 2011
(to appear in IoP Journal of Physics: Conference Series
Thiol-gelatin-norbornene bioink for laserâbased highâdefinition bioprinting
Two-photon polymerization (2PP) is a lithography-based 3D printing method allowing the fabrication of 3D structures with sub-micrometer resolution. This work focuses on the characterization of gelatin-norbornene (Gel-NB) bioinks which enables the embedding of cells via 2PP. The high reactivity of the thiol-ene system allows 2PP processing of cell-containing materials at remarkably high scanning speeds (1000 mm s(-1)) placing this technology in the domain of bioprinting. Atomic force microscopy results demonstrate that the indentation moduli of the produced hydrogel constructs can be adjusted in the 0.2-0.7 kPa range by controlling the 2PP processing parameters. Using this approach gradient 3D constructs are produced and the morphology of the embedded cells is observed in the course of 3 weeks. Furthermore, it is possible to tune the enzymatic degradation of the crosslinked bioink by varying the applied laser power. The 3D printed Gel-NB hydrogel constructs show exceptional biocompatibility, supported cell adhesion, and migration. Furthermore, cells maintain their proliferation capacity demonstrated by Ki-67 immunostaining. Moreover, the results demonstrate that direct embedding of cells provides uniform distribution and high cell loading independently of the pore size of the scaffold. The investigated photosensitive bioink enables high-definition bioprinting of well-defined constructs for long-term cell culture studies
Visuomotor learning promotes visually evoked activity in the medial prefrontal cortex
The medial prefrontal cortex (mPFC) is necessary for executing many learned associations between stimuli and movement. It is unclear, however, how activity in the mPFC evolves across learning, and how this activity correlates with sensory stimuli and the learned movements they evoke. To address these questions, we record cortical activity with widefield calcium imaging while mice learned to associate a visual stimulus with a forelimb movement. After learning, the mPFC shows stimulus-evoked activity both during task performance and during passive viewing, when the stimulus evokes no action. This stimulus-evoked activity closely tracks behavioral performance across training, with both exhibiting a marked increase between days when mice first learn the task, followed by a steady increase with further training. Electrophysiological recordings localized this activity to the secondary motor and anterior cingulate cortex. We conclude that learning a visuomotor task promotes a route for visual information to reach the prefrontal cortex
The effect of whole grain wheat sourdough bread consumption on serum lipids in healthy normoglycemic/normoinsulinemic and hyperglycemic/hyperinsulinemic adults depends on presence of the APOE E3/E3 genotype: a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Epidemiological studies associate consumption of whole grain foods, including breads, with reduced cardiovascular disease (CVD) risk; however, few studies have compared wheat whole grains with wheat refined grains.</p> <p>Methods</p> <p>This study investigated effects of 6-week consumption of whole grain wheat sourdough bread in comparison to white bread on fasting serum lipids in normoglycemic/normoinsulinemic (NGI; n = 14) and hyperglycemic/hyperinsulinemic (HGI; n = 14) adults. The influence of single-nucleotide polymorphisms, 3 within the <it>APOE </it>gene (E2, E3, E4) and 2 within the hepatic lipase gene promoter (<it>LIPC </it>-514C>T, LIPC -250G>A) were considered.</p> <p>Results</p> <p>At baseline, HGI participants had significantly higher body weight, waist circumference, body fat, and fasted glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), glucagon, triacylglycerols (TAG) and TAG:HDL-cholesterol, compared to NGI participants; however, none of these in addition to none of the other serum lipids, differed between bread treatments, within either participant group. For participants with the <it>APOE </it>E3/E3 genotype, LDL-cholesterol (<it>P </it>= 0.02) increased in the NGI group (n = 7), and TAG (<it>P </it>= 0.03) and TAG:HDL-cholesterol (<it>P </it>= 0.04) increased in the HGI group (n = 10), following consumption of whole grain wheat sourdough compared to white bread.</p> <p>Conclusions</p> <p>In summary, 6-week consumption of whole grain wheat sourdough bread did not significantly modulate serum lipids in NGI or HGI adults; however, it significantly increased LDL-cholesterol, TAG and TAG:HDL-cholesterol in participants with the <it>APOE </it>E3/E3 genotype. These data add to limited literature comparing wheat whole grains to wheat refined grains on CVD risk and highlight the need to consider genetic variation in relation to lipoprotein lipid content and CVD risk.</p
Mortality risk during and after opioid substitution treatment: systematic review and meta-analysis of cohort studies
Objective To compare the risk for all cause and overdose mortality in people with opioid dependence during and after substitution treatment with methadone or buprenorphine and to characterise trends in risk of mortality after initiation and cessation of treatment.Design Systematic review and meta-analysis.Data sources Medline, Embase, PsycINFO, and LILACS to September 2016.Study selection Prospective or retrospective cohort studies in people with opioid dependence that reported deaths from all causes or overdose during follow-up periods in and out of opioid substitution treatment with methadone or buprenorphine.Data extraction and synthesis Two independent reviewers performed data extraction and assessed study quality. Mortality rates in and out of treatment were jointly combined across methadone or buprenorphine cohorts by using multivariate random effects meta-analysis.Results There were 19 eligible cohorts, following 122â885 people treated with methadone over 1.3-13.9 years and 15â831 people treated with buprenorphine over 1.1-4.5 years. Pooled all cause mortality rates were 11.3 and 36.1 per 1000 person years in and out of methadone treatment (unadjusted out-to-in rate ratio 3.20, 95% confidence interval 2.65 to 3.86) and reduced to 4.3 and 9.5 in and out of buprenorphine treatment (2.20, 1.34 to 3.61). In pooled trend analysis, all cause mortality dropped sharply over the first four weeks of methadone treatment and decreased gradually two weeks after leaving treatment. All cause mortality remained stable during induction and remaining time on buprenorphine treatment. Overdose mortality evolved similarly, with pooled overdose mortality rates of 2.6 and 12.7 per 1000 person years in and out of methadone treatment (unadjusted out-to-in rate ratio 4.80, 2.90 to 7.96) and 1.4 and 4.6 in and out of buprenorphine treatment.Conclusions Retention in methadone and buprenorphine treatment is associated with substantial reductions in the risk for all cause and overdose mortality in people dependent on opioids. The induction phase onto methadone treatment and the time immediately after leaving treatment with both drugs are periods of particularly increased mortality risk, which should be dealt with by both public health and clinical strategies to mitigate such risk. These findings are potentially important, but further research must be conducted to properly account for potential confounding and selection bias in comparisons of mortality risk between opioid substitution treatments, as well as throughout periods in and out of each treatment.This work was partially supported by the ISCIII Network on Addictive Disorders (Networks for Cooperative Research in Health from the Carlos III Institute of Health) (grant No RD16/0017/0013 and RD12/0028/0018) and by the EMCDDA in the context of the activities related to identification, promotion, and monitor of best practices.S
Comparison of In-Situ, Model and Ground Based In-Flight Icing Severity
As an aircraft flies through supercooled liquid water, the liquid freezes instantaneously to the airframe thus altering its lift, drag, and weight characteristics. In-flight icing is a contributing factor to many aviation accidents, and the reliable detection of this hazard is a fundamental concern to aviation safety. The scientific community has recently developed products to provide in-flight icing warnings. NASA's Icing Remote Sensing System (NIRSS) deploys a vertically--pointing Ka--band radar, a laser ceilometer, and a profiling multi-channel microwave radiometer for the diagnosis of terminal area in-flight icing hazards with high spatial and temporal resolution. NCAR s Current Icing Product (CIP) combines several meteorological inputs to produce a gridded, three-dimensional depiction of icing severity on an hourly basis. Pilot reports are the best and only source of information on in-situ icing conditions encountered by an aircraft. The goal of this analysis was to ascertain how the testbed NIRSS icing severity product and the operational CIP severity product compare to pilot reports of icing severity, and how NIRSS and CIP compare to each other. This study revealed that the icing severity product from the ground-based NASA testbed system compared very favorably with the operational model-based product and pilot reported in-situ icing
Does a pre-hospital emergency pathway improve early diagnosis and referral in suspected stroke patients? â Study protocol of a cluster randomised trial [ISRCTN41456865]
BACKGROUND: Early interventions proved to be able to improve prognosis in acute stroke patients. Prompt identification of symptoms, organised timely and efficient transportation towards appropriate facilities, become essential part of effective treatment. The implementation of an evidence based pre-hospital stroke care pathway may be a method for achieving the organizational standards required to grant appropriate care. We performed a systematic search for studies evaluating the effect of pre-hospital and emergency interventions for suspected stroke patients and we found that there seems to be only a few studies on the emergency field and none about implementation of clinical pathways. We will test the hypothesis that the adoption of emergency clinical pathway improves early diagnosis and referral in suspected stroke patients. We designed a cluster randomised controlled trial (C-RCT), the most powerful study design to assess the impact of complex interventions. The study was registered in the Current Controlled Trials Register: ISRCTN41456865 â Implementation of pre-hospital emergency pathway for stroke â a cluster randomised trial. METHODS/DESIGN: Two-arm cluster-randomised trial (C-RCT). 16 emergency services and 14 emergency rooms were randomised either to arm 1 (comprising a training module and administration of the guideline), or to arm 2 (no intervention, current practice). Arm 1 participants (152 physicians, 280 nurses, 50 drivers) attended an interactive two sessions course with continuous medical education CME credits on the contents of the clinical pathway. We estimated that around 750 patients will be met by the services in the 6 months of observation. This duration allows recruiting a sample of patients sufficient to observe a 30% improvement in the proportion of appropriate diagnoses. Data collection will be performed using current information systems. Process outcomes will be measured at the cluster level six months after the intervention. We will assess the guideline recommendations for emergency and pre-hospital stroke management relative to: 1) promptness of interventions for hyperacute ischaemic stroke; 2) promptness of interventions for hyperacute haemorrhagic stroke 3) appropriate diagnosis. Outcomes will be expressed as proportions of patients with a positive CT for ischaemic stroke and symptoms onset <= 6 hour admitted to the stroke unit. DISCUSSION: The fields in which this trial will play are usually neglected by Randomised Controlled Trial (RCT). We have chosen the Cluster-randomised Controlled Trial (C-RCT) to address the issues of contamination, adherence to real practice, and community dimension of the intervention, with a complex definition of clusters and an extensive use of routine data to collect the outcomes
Melatonin Attenuates Ischemic-like Cell Injury by Promoting Autophagosome Maturation via the Sirt1/FoxO1/Rab7 Axis in Hippocampal HT22 Cells and in Organotypic Cultures
Dysfunctional autophagy is linked to neuronal damage in ischemia/reperfusion injury. The Ras-related protein 7 (Rab7), a member of the Rab family of small GTPases, appears crucial for the progression of the autophagic flux, and its activity is strictly interconnected with the histone deacetylase Silent information regulator 1 (Sirt1) and transcription factor Forkhead box class O1 (FoxO1). The present study assessed the neuroprotective role of melatonin in the modulation of the Sirt1/FoxO1/Rab7 axis in HT22 cells and organotypic hippocampal cultures exposed to oxygen-glucose deprivation followed by reoxygenation (OGD/R). The results showed that melatonin re-established physiological levels of autophagy and reduced propidium iodide-positive cells, speeding up autophagosome (AP) maturation and increasing lysosomal activity. Our study revealed that melatonin modulates autophagic pathways, increasing the expression of both Rab7 and FoxO1 and restoring the Sirt1 expression affected by OGD/R. In addition, the Sirt1 inhibitor EX-527 significantly reduced Rab7, Sirt1, and FoxO1 expression, as well as autolysosomes formation, and blocked the neuroprotective effect of melatonin. Overall, our findings provide, for the first time, new insights into the neuroprotective role of melatonin against ischemic injury through the activation of the Sirt1/FoxO1/Rab7 axis
New insights into the efficient charge transfer of ternary chalcogenides composites of TiO2
Abstract A two-step solvothermal synthesis was adopted to prepare AgXSe2-TiO2 (X = In, Bi) composites. DFT study of the pristine parent samples showed the formation of the hexagonal phase of AgBiSe2, and tetragonal phase of AgInSe2 and TiO2, which corroborated the experimentally synthesised structures. Both the AgBiSe2-TiO2 and AgInSe2-TiO2 composites displayed enhanced visible light absorption and reduced band gap in the UV-DRS patterns. The XPS results exhibited a shift in binding energy values and the TEM results showed the formation of spherical nanoparticles of both AgBiSe2 and AgInSe2. The PL signals displayed delayed recombination of the photogenerated excitons. The as synthesised materials were studied for their photocatalytic efficiency, by hydrogen generation, degradation of doxycycline, and antimicrobial disinfection (E. coli and S. aureus). The composite samples illustrated more than 95 % degradation results within 180 min and showed 5 log reductions of bacterial strains within 30 min of light irradiation. The hydrogen production outcomes were significantly improved as the AgBiSe2 and AgInSe2 based composites illustrated 180-fold and 250-fold enhanced output compared to their parent samples. The enhanced photocatalytic efficiency displayed is attributed to the delayed charge recombination of the photogenerated electron-hole pairs in the AgXSe2-TiO2 interface. Formation of a p-n nano heterojunction for AgBiSe2-TiO2 and type II heterojunction for AgInSe2-TiO2 composite are explained
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