336 research outputs found
An Expanding HI Photodissociated Region Associated with the Compact HII Region G213.880-11.837 in the GGD 14 Complex
We present high angular and spectral resolution HI 21~cm line observations
toward the cometary-shaped compact HII region G213.880-11.837 in the GGD~14
complex.The kinematics and morphology of the photodissociated region, traced by
the HI line emission, reveal that the neutral gas is part of an expanding flow.
The kinematics of the HI gas along the major axis of G213.880-11.837 shows that
the emission is very extended toward the SE direction, reaching LSR radial
velocities in the tail of about 14 km/s. The ambient LSR radial velocity of the
molecular gas is 11.5 km/s, which suggests a champagne flow of the HI gas. This
is the second (after G111.61+0.37) cometary HII/HI region known.Comment: Accepted for publication in the Astronomical Journal (10 pages, 4
figures, 1 table
Sensing sulfur-containing gases using titanium and tin decorated zigzag graphene nanoribbons from first-principles
Atom implantation in graphene or graphene nanoribbons offers a rich opportunity to tune the material structure and functional properties. In this study, zigzag graphene nanoribbons with Ti or Sn adatoms stabilised on a double carbon vacancy site are theoretically studied to investigate their sensitivity to sulfur-containing gases (H2S and SO2). Due to the abundance of oxygen in the atmosphere, we also consider the sensitivity of the structures in the presence of oxygen. Density functional theory calculations are performed to determine the adsorption geometry and energetics, and nonequilibrium Green's function method is employed to compute the current–voltage characteristics of the considered systems. Our results demonstrate the sensitivity of both Ti- and Sn-doped systems to H2S, and the mild sensitivity of Ti-doped sensor systems to SO2. The Ti-doped sensor structure exhibits sensitivity to H2S with or without oxidation, while oxidation of the Sn-doped sensor structure reduces its ability to adsorb H2S and SO2 molecules. Interestingly, oxygen dissociates on the Ti-doped sensor structure, but it does not affect the sensor's response to the H2S gas species. Oxidation prevents the dissociation of the H–S bond when H2S adsorbs on the Ti-doped structure, thus enhancing its reusability for this gas species. Our study suggests the potential of Ti- and Sn-doped graphene in selective gas sensing, irrespective of the sensing performance of the bulk oxides
Mental Health Problems among Children One-Year after Sichuan Earthquake in China: A Follow-up Study
Background: On May 12, 2008, a destructive earthquake registering 8.0 on the Richter scale struck Sichuan Province, southwest China. Beichuan County was the epicenter which was one of the areas nearly completely destroyed by the earthquake. In Beichuan, about 15000 people died and 3000 people were missing. Specially, the earthquake took 1587 students' and 214 teachers' lives from the elementary and middle schools there. The main purpose of the study was to provide a better understanding of mental health problems and associated risk factors among children after earthquake
Social and occupational factors associated with psychological distress and disorder among disaster responders: a systematic review
BACKGROUND: When disasters occur, there are many different occupational groups involved in rescue, recovery and support efforts. This study aimed to conduct a systematic literature review to identify social and occupational factors affecting the psychological impact of disasters on responders. METHODS: Four electronic literature databases (MEDLINE®, Embase, PsycINFO® and Web of Science) were searched and hand searches of reference lists were carried out. Papers were screened against specific inclusion criteria (e.g. published in peer-reviewed journal in English; included a quantitative measure of wellbeing; participants were disaster responders). Data was extracted from relevant papers and thematic analysis was used to develop a list of key factors affecting the wellbeing of disaster responders. RESULTS: Eighteen thousand five papers were found and 111 included in the review. The psychological impact of disasters on responders appeared associated with pre-disaster factors (occupational factors; specialised training and preparedness; life events and health), during-disaster factors (exposure; duration on site and arrival time; emotional involvement; peri-traumatic distress/dissociation; role-related stressors; perceptions of safety, threat and risk; harm to self or close others; social support; professional support) and post-disaster factors (professional support; impact on life; life events; media; coping strategies). CONCLUSIONS: There are steps that can be taken at all stages of a disaster (before, during and after) which may minimise risks to responders and enhance resilience. Preparedness (for the demands of the role and the potential psychological impact) and support (particularly from the organisation) are essential. The findings of this review could potentially be used to develop training workshops for professionals involved in disaster response. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40359-016-0120-9) contains supplementary material, which is available to authorized users
Rates and risks for prolonged grief disorder in a sample of orphaned and widowed genocide survivors
<p>Abstract</p> <p>Background</p> <p>The concept of Prolonged Grief Disorder (PGD) has been defined in recent years by Prigerson and co-workers, who have developed and empirically tested consensus and diagnostic criteria for PGD. Using these most recent criteria defining PGD, the aim of this study was to determine rates of and risks for PGD in survivors of the 1994 Rwandan genocide who had lost a parent and/or the husband before, during or after the 1994 events.</p> <p>Methods</p> <p>The PG-13 was administered to 206 orphans or half orphans and to 194 widows. A regression analysis was carried out to examine risk factors of PGD.</p> <p>Results</p> <p>8.0% (<it>n </it>= 32) of the sample met criteria for PGD with an average of 12 years post-loss. All but one person had faced multiple losses and the majority indicated that their grief-related loss was due to violent death (70%). Grief was predicted mainly by time since the loss, by the violent nature of the loss, the severity of symptoms of posttraumatic stress disorder (PTSD) and the importance given to religious/spiritual beliefs. By contrast, gender, age at the time of bereavement, bereavement status (widow versus orphan), the number of different types of losses reported and participation in the funeral ceremony did not impact the severity of prolonged grief reactions.</p> <p>Conclusions</p> <p>A significant portion of the interviewed sample continues to experience grief over interpersonal losses and unresolved grief may endure over time if not addressed by clinical intervention. Severity of grief reactions may be associated with a set of distinct risk factors. Subjects who lose someone through violent death seem to be at special risk as they have to deal with the loss experience as such and the traumatic aspects of the loss. Symptoms of PTSD may hinder the completion of the mourning process. Religious beliefs may facilitate the mourning process and help to find meaning in the loss. These aspects need to be considered in the treatment of PGD.</p
Prediction of hot spot residues at protein-protein interfaces by combining machine learning and energy-based methods
Background: Alanine scanning mutagenesis is a powerful experimental methodology for investigating the structural and energetic characteristics of protein complexes. Individual aminoacids are systematically mutated to alanine and changes in free energy of binding (Delta Delta G) measured. Several experiments have shown that protein-protein interactions are critically dependent on just a few residues ("hot spots") at the interface. Hot spots make a dominant contribution to the free energy of binding and if mutated they can disrupt the interaction. As mutagenesis studies require significant experimental efforts, there is a need for accurate and reliable computational methods. Such methods would also add to our understanding of the determinants of affinity and specificity in protein-protein recognition.Results: We present a novel computational strategy to identify hot spot residues, given the structure of a complex. We consider the basic energetic terms that contribute to hot spot interactions, i.e. van der Waals potentials, solvation energy, hydrogen bonds and Coulomb electrostatics. We treat them as input features and use machine learning algorithms such as Support Vector Machines and Gaussian Processes to optimally combine and integrate them, based on a set of training examples of alanine mutations. We show that our approach is effective in predicting hot spots and it compares favourably to other available methods. In particular we find the best performances using Transductive Support Vector Machines, a semi-supervised learning scheme. When hot spots are defined as those residues for which Delta Delta G >= 2 kcal/mol, our method achieves a precision and a recall respectively of 56% and 65%.Conclusion: We have developed an hybrid scheme in which energy terms are used as input features of machine learning models. This strategy combines the strengths of machine learning and energy-based methods. Although so far these two types of approaches have mainly been applied separately to biomolecular problems, the results of our investigation indicate that there are substantial benefits to be gained by their integration
Common and Distant Structural Characteristics of Feruloyl Esterase Families from Aspergillus oryzae
Background: Feruloyl esterases (FAEs) are important biomass degrading accessory enzymes due to their capability of cleaving the ester links between hemicellulose and pectin to aromatic compounds of lignin, thus enhancing the accessibility of plant tissues to cellulolytic and hemicellulolytic enzymes. FAEs have gained increased attention in the area of biocatalytic transformations for the synthesis of value added compounds with medicinal and nutritional applications. Following the increasing attention on these enzymes, a novel descriptor based classification system has been proposed for FAEs resulting into 12 distinct families and pharmacophore models for three FAE sub-families have been developed. Methodology/Principal Findings: The feruloylome of Aspergillus oryzae contains 13 predicted FAEs belonging to six sub-families based on our recently developed descriptor-based classification system. The three-dimensional structures of the 13 FAEs were modeled for structural analysis of the feruloylome. The three genes coding for three enzymes, viz., A.O.2, A.O.8 and A.O.10 from the feruloylome of A. oryzae, representing sub-families with unknown functional features, were heterologously expressed in Pichia pastoris, characterized for substrate specificity and structural characterization through CD spectroscopy. Common feature-based pharamacophore models were developed according to substrate specificity characteristics of the three enzymes. The active site residues were identified for the three expressed FAEs by determining the titration curves of amino acid residues as a function of the pH by applying molecular simulations. Conclusions/Significance: Our findings on the structure-function relationships and substrate specificity of the FAEs of A. oryzae will be instrumental for further understanding of the FAE families in the novel classification system. The developed pharmacophore models could be applied for virtual screening of compound databases for short listing the putative substrates prior to docking studies or for post-processing docking results to remove false positives. Our study exemplifies how computational predictions can complement to the information obtained through experimental methods. © 2012 Udatha et al.published_or_final_versio
Direct observation of topoisomerase IA gate dynamics
Type IA topoisomerases cleave single-stranded DNA and relieve negative supercoils in discrete steps corresponding to the passage of the intact DNA strand through the cleaved strand. Although type IA topoisomerases are assumed to accomplish this strand passage via a protein-mediated DNA gate, opening of this gate has never been observed. We developed a single-molecule assay to directly measure gate opening of the Escherichia coli type IA topoisomerases I and III. We found that after cleavage of single-stranded DNA, the protein gate opens by as much as 6.6 nm and can close against forces in excess of 16 pN. Key differences in the cleavage, ligation, and gate dynamics of these two enzymes provide insights into their different cellular functions. The single-molecule results are broadly consistent with conformational changes obtained from molecular dynamics simulations. These results allowed us to develop a mechanistic model of interactions between type IA topoisomerases and single-stranded DNA
A polymeric nanomedicine diminishes inflammatory events in renal tubular cells
The polyglutamic acid/peptoid 1 (QM56) nanoconjugate inhibits apoptosis by interfering with Apaf-1 binding to
procaspase-9. We now describe anti-inflammatory properties of QM56 in mouse kidney and renal cell models.
In cultured murine tubular cells, QM56 inhibited the inflammatory response to Tweak, a non-apoptotic stimulus. Tweak
induced MCP-1 and Rantes synthesis through JAK2 kinase and NF-kB activation. Similar to JAK2 kinase inhibitors, QM56
inhibited Tweak-induced NF-kB transcriptional activity and chemokine expression, despite failing to inhibit NF-kB-p65
nuclear translocation and NF-kB DNA binding. QM56 prevented JAK2 activation and NF-kB-p65(Ser536) phosphorylation.
The anti-inflammatory effect and JAK2 inhibition by QM56 were observed in Apaf-12/2 cells.
In murine acute kidney injury, QM56 decreased tubular cell apoptosis and kidney inflammation as measured by downmodulations
of MCP-1 and Rantes mRNA expression, immune cell infiltration and activation of the JAK2-dependent
inflammatory pathway. In conclusion, QM56 has an anti-inflammatory activity which is independent from its role as
inhibitor of Apaf-1 and apoptosis and may have potential therapeutic relevance.This work was supported by grants from the Instituto de Salud Carlos III (www.isciii.es), FIS: PI07/0020, CP08/1083, PS09/00447 and ISCIII-RETICS
REDINREN RD 06/0016; Sociedad Española de Nefrología (www.senefro.org). Álvaro Ucero, Sergio Berzal and Carlos Ocaña supported by Fundacion Conchita
Rabago (www.fundacionconchitarabago.net), Alberto Ortiz by the Programa de Intensificación de la Actividad Investigadora in the Sistema Nacional de Salud of
the Instituto de Salud Carlos III and the Agencia ‘‘Pedro Lain Entralgo’’ of the Comunidad de Madrid and CIFRA S-BIO 0283/2006 www.madrid.org/lainentralgo)
and Adrián Ramos, by FIS (Programa Miguel Servet)
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