3,010 research outputs found
Brane inflation with dark reheating
In brane world scenarios inflationary vacuum energy may escape into the
higher dimensional bulk leaving behind a dark radiation effect on the brane.
The paper analyses the damping of an inflaton by massless bulk scalar radiation
and the production of dark radiation in a Randall-Sundrum type of model.Comment: 4 pages, ReVTe
MCP-1 overexpressed in tuberous sclerosis lesions acts as a paracrine factor for tumor development
Patients with tuberous sclerosis complex (TSC) develop hamartomatous tumors showing loss of function of the tumor suppressor TSC1 (hamartin) or TSC2 (tuberin) and increased angiogenesis, fibrosis, and abundant mononuclear phagocytes. To identify soluble factors with potential roles in TSC tumorigenesis, we screened TSC skin tumor–derived cells for altered gene and protein expression. Fibroblast-like cells from 10 angiofibromas and five periungual fibromas produced higher levels of monocyte chemoattractant protein-1 (MCP-1) mRNA and protein than did fibroblasts from the same patient's normal skin. Conditioned medium from angiofibroma cells stimulated chemotaxis of a human monocytic cell line to a greater extent than conditioned medium from TSC fibroblasts, an effect blocked by neutralizing MCP-1–specific antibody. Overexpression of MCP-1 seems to be caused by loss of tuberin function because Eker rat embryonic fibroblasts null for Tsc2 (EEF Tsc2 (−/−)) produced 28 times as much MCP-1 protein as did EEF Tsc2 (+/+) cells; transient expression of WT but not mutant human TSC2 by EEF Tsc2 (−/−) cells inhibited MCP-1 production; and pharmacological inhibition of the Rheb-mTOR pathway, which is hyperactivated after loss of TSC2, decreased MCP-1 production by EEF Tsc2 (−/−) cells. Together these findings suggest that MCP-1 is an important paracrine factor for TSC tumorigenesis and may be a new therapeutic target
High-confinement high-Q silicon-rich silicon nitride nonlinear microresonators
We show our results on high-Q high-confinement microresonators based on the silicon-rich silicon nitride (SiRN) platform, featuring broad anomalous dispersion and an enhanced nonlinear Kerr coefficient with respect to stoichiometric Si3N4 technology
Emergence of Hemagglutinin Mutations during the Course of Influenza Infection
Influenza remains a significant cause of disease mortality. The ongoing threat of influenza infection is partly attributable to the emergence of new mutations in the influenza genome. Among the influenza viral gene products, the hemagglutinin (HA) glycoprotein plays a critical role in influenza pathogenesis, is the target for vaccines and accumulates new mutations that may alter the efficacy of immunization. To study the emergence of HA mutations during the course of infection, we employed a deep-targeted sequencing method. We used samples from 17 patients with active H1N1 or H3N2 influenza infections. These patients were not treated with antivirals. In addition, we had samples from five patients who were analyzed longitudinally. Thus, we determined the quantitative changes in the fractional representation of HA mutations during the course of infection. Across individuals in the study, a series of novel HA mutations directly altered the HA coding sequence were identified. Serial viral sampling revealed HA mutations that either were stable, expanded or were reduced in representation during the course of the infection. Overall, we demonstrated the emergence of unique mutations specific to an infected individual and temporal genetic variation during infection
Ram pressure stripping in elliptical galaxies: I. the impact of the interstellar medium turbulence
Elliptical galaxies contain X-ray emitting gas that is subject to continuous
ram pressure stripping over timescales comparable to cluster ages. The gas in
these galaxies is not in perfect hydrostatic equilibrium. Supernova feedback,
stellar winds, or active galactic nuclei (AGN) feedback can significantly
perturb the interstellar medium (ISM). Using hydrodynamical simulations, we
investigate the effect of subsonic turbulence in the hot ISM on the ram
pressure stripping process in early-type galaxies. We find that galaxies with
more turbulent ISM produce longer, wider, and more smoothly distributed tails
of the stripped ISM than those characterised by weaker ISM turbulence. Our main
conclusion is that even very weak internal turbulence, at the level of <15% of
the average ISM sound speed, can significantly accelerate the gas removal from
galaxies via ram pressure stripping. The magnitude of this effect increases
sharply with the strength of turbulence. As most of the gas stripping takes
place near the boundary between the ISM and the intraclustermedium (ICM), the
boost in the ISM stripping rate is due to the "random walk" of the ISM from the
central regions of the galactic potential well to larger distances, where the
ram pressure is able to permanently remove the gas from galaxies. The ICM can
be temporarily trapped inside the galactic potential well due to the mixing of
the turbulent ISM with the ICM. The galaxies with more turbulent ISM, yet still
characterised by very weak turbulence, can hold larger amounts of the ICM.
[Abridged]Comment: 12 pages, 11 figures, 2 tables; accepted for publication in MNRA
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High-throughput monitoring of wild bee diversity and abundance via mitogenomics
1. Bee populations and other pollinators face multiple, synergistically acting threats, which have led to population declines, loss of local species richness and pollination services, and extinctions. However, our understanding of the degree, distribution and causes of declines is patchy, in part due to inadequate monitoring systems, with the challenge of taxonomic identification posing a major logistical barrier. Pollinator conservation would benefit from a high-throughput identification pipeline.
2. We show that the metagenomic mining and resequencing of mitochondrial genomes (mitogenomics) can be applied successfully to bulk samples of wild bees. We assembled the mitogenomes of 48 UK bee species and then shotgun-sequenced total DNA extracted from 204 whole bees that had been collected in 10 pan-trap samples from farms in England and been identified morphologically to 33 species. Each sample data set was mapped
against the 48 reference mitogenomes.
3. The morphological and mitogenomic data sets were highly congruent. Out of 63 total species detections in the morphological data set, the mitogenomic data set made 59 correct detections (93�7% detection rate) and detected
six more species (putative false positives). Direct inspection and an analysis with species-specific primers suggested that these putative false positives were most likely due to incorrect morphological IDs. Read frequency
significantly predicted species biomass frequency (R2 = 24�9%). Species lists, biomass frequencies, extrapolated
species richness and community structure were recovered with less error than in a metabarcoding pipeline.
4. Mitogenomics automates the onerous task of taxonomic identification, even for cryptic species, allowing the
tracking of changes in species richness and istributions. A mitogenomic pipeline should thus be able to contain
costs, maintain consistently high-quality data over long time series, incorporate retrospective taxonomic revisions and provide an auditable evidence trail. Mitogenomic data sets also provide estimates of species counts within samples and thus have potential for tracking population trajectories
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Climate Change Science Program Overview and Management
This program identifies the following criteria of interest: scientific or technical quality; relevance to reducing uncertainties and improving decision support tools; track record of consistently good past
performance and identified metrics for evaluating future progress; and cost and value
A Case of Neck Abscess Caused by Salmonella Serotype D in a Patient with Liver Cirrhosis
Non-typhoidal salmonellosis, which is increasing nowadays in Korea as well as in the developed countries, is manifested as enteritis in most cases, but it also encompasses bacteremia, intraabdominal infections, and bone, joint and soft tissue infections. These rare diseases are known to result from primary gastrointestinal infection and subsequent bacteremia with or without symptoms. We experienced a case of neck abscess caused by Salmonella serotype D, which is a rare but important differential diagnosis of neck abscess. We herein report it
Protocol for the development of a core outcome set for studies of pregnant women with pre-existing multimorbidity
Increasingly more pregnant women are living with pre-existing multimorbidity (≥two long-term physical or mental health conditions). This may adversely affect maternal and offspring outcomes. This study aims to develop a core outcome set (COS) for maternal and offspring outcomes in pregnant women with pre-existing multimorbidity. It is intended for use in observational and interventional studies in all pregnancy settings. We propose a four stage study design: (1) systematic literature search, (2) focus groups, (3) Delphi surveys and (4) consensus group meeting. The study will be conducted from June 2021 to August 2022. First, an initial list of outcomes will be identified through a systematic literature search of reported outcomes in studies of pregnant women with multimorbidity. We will search the Cochrane library, Medline, EMBASE and CINAHL. This will be supplemented with relevant outcomes from published COS for pregnancies and childbirth in general, and multimorbidity. Second, focus groups will be conducted among (1) women with lived experience of managing pre-existing multimorbidity in pregnancy (and/or their partners) and (2) their healthcare/social care professionals to identify outcomes important to them. Third, these initial lists of outcomes will be prioritised through a three-round online Delphi survey using predefined score criteria for consensus. Participants will be invited to suggest additional outcomes that were not included in the initial list. Finally, a consensus meeting using the nominal group technique will be held to agree on the final COS. The stakeholders will include (1) women (and/or their partners) with lived experience of managing multimorbidity in pregnancy, (2) healthcare/social care professionals involved in their care and (3) researchers in this field. This study has been approved by the University of Birmingham's ethical review committee. The final COS will be disseminated through peer-reviewed publication and conferences and to all stakeholders. [Abstract copyright: © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.
Effect of Pertussis Toxin and Herbimycin A on Proteinase-Activated Receptor 2-Mediated Cyclooxygenase 2 Expression in Helicobacter pylori-Infected Gastric Epithelial AGS Cells
Helicobacter pylori (H. pylori) is an important risk factor for chronic gastritis, peptic ulcer, and gastric cancer. Proteinase-activated receptor 2 (PAR2), subgroup of G-protein coupled receptor family, is highly expressed in gastric cancer, and chronic expression of cyclooxygenase-2 (COX-2) plays an important role in H. pylori-associated gastric carcinogenesis and inflammation. We previously demonstrated that H. pylori induced the expression of PAR2 and COX-2 in gastric epithelial cells. Present study aims to investigate whether COX-2 expression induced by H. pylori in Korean isolates is mediated by PAR2 via activation of Gi protein and Src kinase in gastric epithelial AGS cells. Results showed that H. pylori-induced COX-2 expression was inhibited in the cells transfected with antisense oligonucleotide for PAR2 or treated with Gi protein blocker pertussis toxin, Src kinase inhibitor herbimycin A and soybean trypsin inbitor, indicating that COX-2 expression is mediated by PAR2 through activation of Gi protein and Src kinase in gastric epithelial cells infected with H. pylori in Korean isolates. Thus, targeting the activation of PAR2 may be beneficial for prevention or treatment of gastric inflammation and carcinogenesis associated with H. pylori infection
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