1,471 research outputs found
Motion of a Particle with Isospin in the Presence of a Monopole
From a consistent expression for the quadriforce describing the interaction
between a coloured particle and gauge fields, we investigate the relativistic
motion of a particle with isospin interacting with a BPS monopole and with a
Julia-Zee dyon. The analysis of such systems reveals the existence of
unidimensional unbounded motion and asymptotic trajectories restricted to
conical surfaces, which resembles the equivalent case of Electromagnetism.Comment: 10 pages, 2 figures, onecolum
The universal functorial equivariant Lefschetz invariant
We introduce the universal functorial equivariant Lefschetz invariant for
endomorphisms of finite proper G-CW-complexes, where G is a discrete group. We
use K_0 of the category of "phi-endomorphisms of finitely generated free
RPi(G,X)-modules". We derive results about fixed points of equivariant
endomorphisms of cocompact proper smooth G-manifolds.Comment: 33 pages; shortened version of the author's PhD thesis, supervised by
Wolfgang Lueck, Westfaelische Wilhelms-Universitaet Muenster, 200
Relations Between Molecular Cloud Structure Sizes and Line Widths in the Large Magellanic Cloud
We present a comparative study of the size-line width relation for
substructures within six molecular clouds in the Large Magellanic Cloud (LMC)
mapped with the Atacama Large Millimeter/submillimeter Array (ALMA). Our sample
extends our previous study, which compared a Planck detected cold cloud in the
outskirts of the LMC with the 30 Doradus molecular cloud and found the typical
line width for 1 pc radius structures to be 5 times larger in 30 Doradus. By
observing clouds with intermediate levels of star formation activity, we find
evidence that line width at a given size increases with increasing local and
cloud-scale 8m intensity. At the same time, line width at a given size
appears to independently correlate with measures of mass surface density. Our
results suggest that both virial-like motions due to gravity and local energy
injection by star formation feedback play important roles in determining
intracloud dynamics.Comment: 20 pages, to appear in ApJ. Data presented in this paper can be found
at https://mmwave.astro.illinois.edu/almalmc
Clinical and Experimental Applications of NIR-LED Photobiomodulation
This review presents current research on the use of far-red to near-infrared (NIR) light treatment in various in vitro and in vivo models. Low-intensity light therapy, commonly referred to as âphotobiomodulation,â uses light in the far-red to near-infrared region of the spectrum (630â1000 nm) and modulates numerous cellular functions. Positive effects of NIRâlight-emitting diode (LED) light treatment include acceleration of wound healing, improved recovery from ischemic injury of the heart, and attenuated degeneration of injured optic nerves by improving mitochondrial energy metabolism and production. Various in vitro and in vivo models of mitochondrial dysfunction were treated with a variety of wavelengths of NIR-LED light. These studies were performed to determine the effect of NIR-LED light treatment on physiologic and pathologic processes. NIRLED light treatment stimulates the photoacceptor cytochrome c oxidase, resulting in increased energy metabolism and production. NIR-LED light treatment accelerates wound healing in ischemic rat and murine diabetic wound healing models, attenuates the retinotoxic effects of methanol-derived formic acid in rat models, and attenuates the developmental toxicity of dioxin in chicken embryos. Furthermore, NIR-LED light treatment prevents the development of oral mucositis in pediatric bone marrow transplant patients. The experimental results demonstrate that NIR-LED light treatment stimulates mitochondrial oxidative metabolism in vitro, and accelerates cell and tissue repair in vivo. NIR-LED light represents a novel, noninvasive, therapeutic intervention for the treatment of numerous diseases linked to mitochondrial dysfunction
Family physiciansâ roles in long-term care homes and other congregate residential care settings during the COVID-19 pandemic: a qualitative study
Context: The COVID-19 pandemic disproportionally affected long-term care (LTC) homes and other community-based congregate residential care settings. Although family physicians (FPs) play important roles in the care of residents in LTC homes, provincial pandemic plans make few references to their specific roles in LTC. Objective: To examine the experiences of FPs providing care in LTC homes and other congregate care settings in Canada during the first year of the COVID-19 pandemic (2020â2021). Methods: As part of a multiple case study, we conducted semi-structured qualitative interviews with FPs across four Canadian regions. Interviews were transcribed, and a thematic analysis approach was employed. Findings: Twenty-one of the 68 FPs interviewed discussed providing care in congregate residential settings, including LTC. We identified three major themes: 1) the roles of FPs in community-based congregate residential care settings during a pandemic, 2) modification of the delivery of routine care, and 3) special workforce considerations in pandemic response for community-based congregate residential care settings. Limitations: We interviewed FPs in four Canadian jurisdictions between October 2020 and June 2021; findings may not be generalisable to later pandemic stages or to other provinces. Our recruitment strategy did not specifically target FPs who worked in different types of congregate residential care facilities; further research is needed to examine these settings in greater depth. Implications: FPs have a unique understanding of the populations they serve and are well suited to plan and implement community-adaptive procedures. Future pandemic plans should implement LTC-related FP roles during the pre-pandemic stage of a pandemic response
Significance of somatic mutations and content alteration of mitochondrial DNA in esophageal cancer
BACKGROUND: The roles of mitochondria in energy metabolism, the generation of ROS, aging, and the initiation of apoptosis have implicated their importance in tumorigenesis. In this study we aim to establish the mutation spectrum and to understand the role of somatic mtDNA mutations in esophageal cancer. METHODS: The entire mitochondrial genome was screened for somatic mutations in 20 pairs (18 esophageal squamous cell carcinomas, one adenosquamous carcinoma and one adenocarcinoma) of tumor/surrounding normal tissue of esophageal cancers, using temporal temperature gradient gel electrophoresis (TTGE), followed by direct DNA sequencing to identify the mutations. RESULTS: Fourteen somatic mtDNA mutations were identified in 55% (11/20) of tumors analyzed, including 2 novel missense mutations and a frameshift mutation in ND4L, ATP6 subunit, and ND4 genes respectively. Nine mutations (64%) were in the D-loop region. Numerous germline variations were found, at least 10 of them were novel and five were missense mutations, some of them occurred in evolutionarily conserved domains. Using real-time quantitative PCR analysis, the mtDNA content was found to increase in some tumors and decrease in others. Analysis of molecular and other clinicopathological findings does not reveal significant correlation between somatic mtDNA mutations and mtDNA content, or between mtDNA content and metastatic status. CONCLUSION: Our results demonstrate that somatic mtDNA mutations in esophageal cancers are frequent. Some missense and frameshift mutations may play an important role in the tumorigenesis of esophageal carcinoma. More extensive biochemical and molecular studies will be necessary to determine the pathological significance of these somatic mutations
Magnesium supplementation for the treatment of restless legs syndrome and periodic limb movement disorder : A systematic review
Magnesium supplementation is often suggested for restless legs syndrome (RLS) or period limb movement disorder (PLMD) based on anecdotal evidence that it relieves symptoms and because it is also commonly recommended for leg cramps. We aimed to review all articles reporting the effects of magnesium supplementation on changes in RLS and/or PLMD. We conducted a systematic search looking for all relevant articles and then two reviewers read all article titles and abstracts to identify relevant studies. Eligible studies were scored for their quality as interventional trials. We found 855 abstracts and 16 of these could not be definitively excluded for not addressing all aspects of our research question. Seven full-text articles were unlocatable and one was ineligible which left eight studies with relevant data. One was a randomised placebo-controlled trial, three were case series and four were case studies. The RCT did not find a significant treatment effect of magnesium but may have been underpowered. After quality appraisal and synthesis of the evidence we were unable to make a conclusion as to the effectiveness of magnesium for RLS/PLMD. It is not clear whether magnesium helps relieve RLS or PLMD or in which patient groups any benefit might be seen. (c) 2019 Elsevier Ltd. All rights reserved.Peer reviewe
Low Temperature Opacities
Previous computations of low temperature Rosseland and Planck mean opacities
from Alexander & Ferguson (1994) are updated and expanded. The new computations
include a more complete equation of state with more grain species and updated
optical constants. Grains are now explicitly included in thermal equilibrium in
the equation of state calculation, which allows for a much wider range of grain
compositions to be accurately included than was previously the case. The
inclusion of high temperature condensates such as AlO and CaTiO
significantly affects the total opacity over a narrow range of temperatures
before the appearance of the first silicate grains.
The new opacity tables are tabulated for temperatures ranging from 30000 K to
500 K with gas densities from 10 g cm to 10 g cm.
Comparisons with previous Rosseland mean opacity calculations are discussed. At
high temperatures, the agreement with OPAL and Opacity Project is quite good.
Comparisons at lower temperatures are more divergent as a result of differences
in molecular and grain physics included in different calculations. The
computation of Planck mean opacities performed with the opacity sampling method
are shown to require a very large number of opacity sampling wavelength points;
previously published results obtained with fewer wavelength points are shown to
be significantly in error. Methods for requesting or obtaining the new tables
are provided.Comment: 39 pages with 12 figures. To be published in ApJ, April 200
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Effect of a 6-month vegan low-carbohydrate (âEco-Atkinsâ) diet on cardiovascular risk factors and body weight in hyperlipidaemic adults: a randomised controlled trial
Objective: Low-carbohydrate diets may be useful for weight loss. Diets high in vegetable proteins and oils may reduce the risk of coronary heart disease. The main objective was to determine the longer term effect of a diet that was both low-carbohydrate and plant-based on weight loss and low-density lipoprotein cholesterol (LDL-C). Design, setting, participants A parallel design study of 39 overweight hyperlipidaemic men and postmenopausal women conducted at a Canadian university-affiliated hospital nutrition research centre from April 2005 to November 2006. Intervention Participants were advised to consume either a low-carbohydrate vegan diet or a high-carbohydrate lacto-ovo vegetarian diet for 6 months after completing 1-month metabolic (all foods provided) versions of these diets. The prescribed macronutrient intakes for the low-carbohydrate and high-carbohydrate diets were: 26% and 58% of energy from carbohydrate, 31% and 16% from protein and 43% and 25% from fat, respectively. Primary outcome Change in body weight. Results: 23 participants (50% test, 68% control) completed the 6-month ad libitum study. The approximate 4 kg weight loss on the metabolic study was increased to â6.9 kg on low-carbohydrate and â5.8 kg on high-carbohydrate 6-month ad libitum treatments (treatment difference (95% CI) â1.1 kg (â2.1 to 0.0), p=0.047). The relative LDL-C and triglyceride reductions were also greater on the low-carbohydrate treatment (treatment difference (95% CI) â0.49 mmol/L (â0.70 to â0.28), p<0.001 and â0.34 mmol/L (â0.57 to â0.11), p=0.005, respectively), as were the total cholesterol:HDL-C and apolipoprotein B:A1 ratios (â0.57 (â0.83, â0.32), p<0.001 and â0.05 (â0.09, â0.02), p=0.003, respectively). Conclusions: A self-selected low-carbohydrate vegan diet, containing increased protein and fat from gluten and soy products, nuts and vegetable oils, had lipid lowering advantages over a high-carbohydrate, low-fat weight loss diet, thus improving heart disease risk factors. Trial Registration clinicaltrials.gov (http://www.clinicaltrials.gov/), #NCT00256516
LKB1 loss links serine metabolism to DNA methylation and tumorigenesis
Intermediary metabolism generates substrates for chromatin modification, enabling the potential coupling of metabolic and epigenetic states. Here we identify a network linking metabolic and epigenetic alterations that is central to oncogenic transformation downstream of the liver kinase B1 (LKB1, also known as STK11) tumour suppressor, an integrator of nutrient availability, metabolism and growth. By developing genetically engineered mouse models and primary pancreatic epithelial cells, and employing transcriptional, proteomics, and metabolic analyses, we find that oncogenic cooperation between LKB1 loss and KRAS activation is fuelled by pronounced mTOR-dependent induction of the serine-glycine-one-carbon pathway coupled to S-adenosylmethionine generation. At the same time, DNA methyltransferases are upregulated, leading to elevation in DNA methylation with particular enrichment at retrotransposon elements associated with their transcriptional silencing. Correspondingly, LKB1 deficiency sensitizes cells and tumours to inhibition of serine biosynthesis and DNA methylation. Thus, we define a hypermetabolic state that incites changes in the epigenetic landscape to support tumorigenic growth of LKB1-mutant cells, while resulting in potential therapeutic vulnerabilities
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