3,034 research outputs found

    Haze in the Klang Valley of Malaysia

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    Continuous measurements of dry aerosol light scattering (Bsp) were made at two sites in the Klang Valley of Malaysia between December 1998 and December 2000. In addition 24-h PM2.5 samples were collected on a one-day-in-six cycle and the chemical composition of the aerosol was determined. Periods of excessive haze were defined as 24-h average Bsp values greater than 150 Mm-1 and these occurred on a number of occasions, between May and September 1999, during May 2000, and between July and September 2000. The evidence for smoke being a significant contributor to aerosol during periods of excessive haze is discussed and includes features of the aerosol chemistry, the diurnal cycle of Bsp, and the coincidence of forest fires on Sumatra during the southwest (SW) monsoon period, as well as transport modelling for one week of the southwest Monsoon of 2000. The study highlights that whilst transboundary smoke is a major contributor to poor visibility in the Klang Valley, smoke from fires on Peninsular Malaysia is also a contributor, and at all times, the domestic source of secondary particle production is present

    Quasiparticle properties in a density functional framework

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    We propose a framework to construct the ground-state energy and density matrix of an N-electron system by solving selfconsistently a set of single-particle equations. The method can be viewed as a non-trivial extension of the Kohn-Sham scheme (which is embedded as a special case). It is based on separating the Green's function into a quasi-particle part and a background part, and expressing only the background part as a functional of the density matrix. The calculated single-particle energies and wave functions have a clear physical interpretation as quasiparticle energies and orbitals.Comment: 12 pages, 1 figure, to be published in Phys. Rev.

    Creating a National Coalition to Address Tractor Overturn Fatalities.

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    Tractor overturns continue to be the leading cause of death on U.S. farms. While rollover protective structures (ROPS) are effective in preventing these fatalities, they are underutilized due to a number of barriers. Past programs in the U.S. and abroad have targeted this area of agricultural safety; however, a national program is not yet in place for U.S. farmers. This study seeks to build a national partnership to address tractor overturn fatalities by increasing the number of tractors with ROPS. A diverse, multisector steering committee has been organized and is working together using Whole System in a Room methods. This method brings together partners from nine stakeholder groups to identify and commit to a collaborative solution to the issue

    Mutations underlying Episodic Ataxia type-1 antagonize Kv1.1 RNA editing

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 7 (2017): 41095, doi:10.1038/srep41095.Adenosine-to-inosine RNA editing in transcripts encoding the voltage-gated potassium channel Kv1.1 converts an isoleucine to valine codon for amino acid 400, speeding channel recovery from inactivation. Numerous Kv1.1 mutations have been associated with the human disorder Episodic Ataxia Type-1 (EA1), characterized by stress-induced ataxia, myokymia, and increased prevalence of seizures. Three EA1 mutations, V404I, I407M, and V408A, are located within the RNA duplex structure required for RNA editing. Each mutation decreased RNA editing both in vitro and using an in vivo mouse model bearing the V408A allele. Editing of transcripts encoding mutant channels affects numerous biophysical properties including channel opening, closing, and inactivation. Thus EA1 symptoms could be influenced not only by the direct effects of the mutations on channel properties, but also by their influence on RNA editing. These studies provide the first evidence that mutations associated with human genetic disorders can affect cis-regulatory elements to alter RNA editing.This work was supported by the Vanderbilt Molecular Endocrinology Training Program (T32DK007563; E.A.F.K.), a Ruth L. Kirschstein National Research Service Award (F31NS087911; E.A.F.K), a Vanderbilt Dissertation Enhancement Grant (E.A.F.K.), and the Vanderbilt Joel G. Hardman Chair in Pharmacology (R.B.E). Additional support for J.J.C.R. included NINDS (R0111223855, R01NS64259) and the Cystic Fibrosis Foundation Therapeutics (Rosent14XXO). Infrastructural support for J.J.C.R. was provided by NIGMS (P20GM103642), NIMH (G12-MD007600), and NSF (DBI 0115825, DBI 1337284)

    Advice for Health Care Professionals and Users: An Evaluation of Websites for Perinatal Anxiety

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    Background: Many websites are available with information and resources for perinatal anxiety; however, there is limited research on the quality and content of these sites. Objective: This study aims to identify what sites are available on perinatal anxiety, identify any information and therapeutic advice given, and review its accuracy and website design. Methods: We conducted an evaluation of websites for perinatal anxiety. Eligible websites (N=50) were evaluated for accuracy of information, resources for mothers, website quality, and readability. Results: Information was often incomplete and focused on symptoms rather than risk factors or impact of untreated perinatal anxiety. Websites often had information on treatment (46/50, 92%), but much less on screening (19/50, 38%). Most sites provided at least some resources to support mothers (49/50, 98%), but active, guided support was infrequent (25/50, 50%). Website quality was extremely variable and mostly difficult to read (42/50, 84%). Conclusions: This study recommends the top 4 websites on perinatal anxiety for health care professionals and users. There is a need for websites to be developed that provide accurate, evidence-based information that women can relate to with quality support resources. Furthermore, these sites should be easy to use and readable

    Effects of Microgravity on the Formation of Aerogels

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    This paper describes research to investigate fundamental aspects of the effects of microgravity on the formation of the microstructure of metal oxide alcogels and aerogels. We are studying the role of gravity on pore structure and gel uniformity in collaboration with Marshall Space Flight Center (MSFC) on gelling systems under microgravity conditions. While this project was just initiated in May 1998, related research performed earlier is described along with the plans and rationale for the current microgravity investigation to provide background and describe newly developing techniques that should be useful for the current gellation studies. The role of gravity in materials processing must be investigated through the study of well-mastered systems. Sol-gel processed materials are near-perfect candidates to determine the effect of gravity on the formation and growth of random clusters from hierarchies of aggregated units. The processes of hydrolysis, condensation, aggregation and gellation in the formation of alcogels are affected by gravity and therefore provide a rich system to study under microgravity conditions. Supercritical drying of the otherwise unstable wet alcogel preserves the alcogel structure produced during sol-gel processing as aerogel. Supercritically dried aerogel provides for the study of material microstructures without interference from the effects of surface tension, evaporation, and solvent flow. Aerogels are microstructured, low density open-pore solids. They have many unusual properties including: transparency, excellent thermal resistance, high surface area, very low refractive index, a dielectric constant approaching that of air, and extremely low sound velocity. Aerogels are synthesized using sol-gel processing followed by supercritical solvent extraction that leaves the original gel structure virtually intact. These studies will elucidate the effects of microgravity on the homogeneity of the microstructure and porosity of aerogel. The presence of poorly controlled microporosity in aerogel leads to material non-uniformity that gives rise to increased light scattering. Investigation of the effect of gravity driven solute flows within microclusters and their effect on condensation and agglomeration reactions will enable us to improve the preparation and properties of aerogel. Increased clarity of images viewed through aerogel and decreased scattering from the pores of aerogel will significantly improve the prospects for large-scale adoption of aerogel in such applications as transparent insulating windows, high performance thermal insulation, and Cherenkov detectors

    Do Younger TKR and THR Patients Have Similar Disability at Time of Surgery as Older Adults? Lessons from FORCE-TJR

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    Introduction: The number of US patients under 65 year old who are undergoing total knee replacement (TKR) and total hip replacement (THR) has been rising, raising concerns that younger patients may receive surgery prematurely. Therefore, we examined demographics and clinical factors and compared the severity of operative knee pain and functional status in younger versus older TKR patients from a US national sample. Materials & methods: The FORCE-TJR registry gathers data from patients, surgeons and hospitals on sociodemographic factors (age, sex, race), BMI, comorbid conditions using the modified Charlson comorbidity scores, burden of musculoskeletal disease using the Knee/Hip injury and Osteoarthritis Outcome Score (KOOS/HOOS) in both knees and hips, emotional health based on the Short Form 36 (SF-36) Mental Component Score (MCS) and physical function based on the Physical Component Score (SF-36 PCS). Results: We analysed data from 2035 younger (\u3c65) and 3084 older (≥65) TKR patients and 1780 younger and 1831 older THR patients. Younger TKR and THR patients were more likely nonwhite (TKR: 13.1% vs. 6.6%; THR: 51.7% vs. 48.3%),), with greater body mass index (mean BMI TKR: 33.1 vs. 30.5; THR: 29.9 vs. 28.4), smokers, had fewer number of comorbid conditions. Younger TKR patients reported lower emotional health (MCS 49.1 vs. 52.6), greater joint pain, stiffness and functional impairment (based on estimated WOMAC) and global functional impairment (using PCS). Younger THR patients reported greater joint pain, stiffness and functional impairment (estimated WOMAC) but not global function. Conclusion: At the time of TKR and THR, younger patients have fewer medical illnesses, but higher rates of obesity and smoking as well as lower mental health scores. Younger have the same or greater joint specific and global functional impairment compared to older patients, suggesting surgeons use comparable standards for selecting TKR and THR candidates in younger and older adults

    Integrative analysis of next generation sequencing for small non-coding RNAs and transcriptional regulation in Myelodysplastic Syndromes

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    Abstract. Background: Myelodysplastic Syndromes (MDSS) are pre-leukemic disorders with increasing incident rates worldwide, but very limited treatment options. Little is known about small regulatory RNAs and how they contribute to pathogenesis, progression and transcriptome changes in MDS. Methods. Patients' primary marrow cells were screened for short RNAs (RNA-seq) using next generation sequencing. Exon arrays from the same cells were used to profile gene expression and additional measures on 98 patients obtained. Integrative bioinformatics algorithms were proposed, and pathway and ontology analysis performed. Results: In low-grade MDS, observations implied extensive post-transcriptional regulation via microRNAs (miRNA) and the recently discovered Piwi interacting RNAs (piRNA). Large expression differences were found for MDS-associated and novel miRNAs, including 48 sequences matching to miRNA star (miRNA*) motifs. The detected species were predicted to regulate disease stage specific molecular functions and pathways, including apoptosis and response to DNA damage. In high-grade MDS, results suggested extensive post-translation editing via transfer RNAs (tRNAs), providing a potential link for reduced apoptosis, a hallmark for this disease stage. Bioinformatics analysis confirmed important regulatory roles for MDS linked miRNAs and TFs, and strengthened the biological significance of miRNA*. The "RNA polymerase II promoters" were identified as the tightest controlled biological function. We suggest their control by a miRNA dominated feedback loop, which might be linked to the dramatically different miRNA amounts seen between low and high-grade MDS. Discussion. The presented results provide novel findings that build a basis of further investigations of diagnostic biomarkers, targeted therapies and studies on MDS pathogenesis. © 2011 Beck et al; licensee BioMed Central Ltd
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