1,102 research outputs found
Optically trapped bacteria pairs reveal discrete motile response to control aggregation upon cellâcell approach
Aggregation of bacteria plays a key role in the formation of many biofilms. The critical first step is cellâcell approach, and yet the ability of bacteria to control the likelihood of aggregation during this primary phase is unknown. Here, we use optical tweezers to measure the force between isolated Bacillus subtilis cells during approach. As we move the bacteria towards each other, cell motility (bacterial swimming) initiates the generation of repulsive forces at bacterial separations of ~3 ÎŒm. Moreover, the motile response displays spatial sensitivity with greater cellâcell repulsion evident as inter-bacterial distances decrease. To examine the environmental influence on the inter-bacterial forces, we perform the experiment with bacteria suspended in Tryptic Soy Broth, NaCl solution and deionised water. Our experiments demonstrate that repulsive forces are strongest in systems that inhibit biofilm formation (Tryptic Soy Broth), while attractive forces are weak and rare, even in systems where biofilms develop (NaCl solution). These results reveal that bacteria are able to control the likelihood of aggregation during the approach phase through a discretely modulated motile response. Clearly, the force-generating motility we observe during approach promotes biofilm prevention, rather than biofilm formation
Aerobic Exercise Training Reduces Cannabis Craving and Use in Non-Treatment Seeking Cannabis-Dependent Adults
Cannabis dependence is a significant public health problem. Because there are no approved medications for this condition, treatment must rely on behavioral approaches empirically complemented by such lifestyle change as exercise.To examine the effects of moderate aerobic exercise on cannabis craving and use in cannabis dependent adults under normal living conditions.Participants attended 10 supervised 30-min treadmill exercise sessions standardized using heart rate (HR) monitoring (60-70% HR reserve) over 2 weeks. Exercise sessions were conducted by exercise physiologists under medical oversight.Sedentary or minimally active non-treatment seeking cannabis-dependent adults (nâ=â12, age 25±3 years, 8 females) met criteria for primary cannabis dependence using the Substance Abuse module of the Structured Clinical Interview for DSM-IV (SCID).Self-reported drug use was assessed for 1-week before, during, and 2-weeks after the study. Participants viewed visual cannabis cues before and after exercise in conjunction with assessment of subjective cannabis craving using the Marijuana Craving Questionnaire (MCQ-SF).Daily cannabis use within the run-in period was 5.9 joints per day (SDâ=â3.1, range 1.8-10.9). Average cannabis use levels within the exercise (2.8 joints, SDâ=â1.6, range 0.9-5.4) and follow-up (4.1 joints, SDâ=â2.5, range 1.1-9.5) periods were lower than during the run-in period (both P<.005). Average MCQ factor scores for the pre- and post-exercise craving assessments were reduced for compulsivity (P â=â.006), emotionality (P â=â.002), expectancy (P â=â.002), and purposefulness (P â=â.002).The findings of this pilot study warrant larger, adequately powered controlled trials to test the efficacy of prescribed moderate aerobic exercise as a component of cannabis dependence treatment. The neurobiological mechanisms that account for these beneficial effects on cannabis use may lead to understanding of the physical and emotional underpinnings of cannabis dependence and recovery from this disorder.ClinicalTrials.gov NCT00838448]
Mapping gene associations in human mitochondria using clinical disease phenotypes
Nuclear genes encode most mitochondrial proteins, and their mutations cause diverse and debilitating clinical disorders. To date, 1,200 of these mitochondrial genes have been recorded, while no standardized catalog exists of the associated clinical phenotypes. Such a catalog would be useful to develop methods to analyze human phenotypic data, to determine genotype-phenotype relations among many genes and diseases, and to support the clinical diagnosis of mitochondrial disorders. Here we establish a clinical phenotype catalog of 174 mitochondrial disease genes and study associations of diseases and genes. Phenotypic features such as clinical signs and symptoms were manually annotated from full-text medical articles and classified based on the hierarchical MeSH ontology. This classification of phenotypic features of each gene allowed for the comparison of diseases between different genes. In turn, we were then able to measure the phenotypic associations of disease genes for which we calculated a quantitative value that is based on their shared phenotypic features. The results showed that genes sharing more similar phenotypes have a stronger tendency for functional interactions, proving the usefulness of phenotype similarity values in disease gene network analysis. We then constructed a functional network of mitochondrial genes and discovered a higher connectivity for non-disease than for disease genes, and a tendency of disease genes to interact with each other. Utilizing these differences, we propose 168 candidate genes that resemble the characteristic interaction patterns of mitochondrial disease genes. Through their network associations, the candidates are further prioritized for the study of specific disorders such as optic neuropathies and Parkinson disease. Most mitochondrial disease phenotypes involve several clinical categories including neurologic, metabolic, and gastrointestinal disorders, which might indicate the effects of gene defects within the mitochondrial system. The accompanying knowledgebase (http://www.mitophenome.org/) supports the study of clinical diseases and associated genes
A systematic review of the literature on the effectiveness of exercise therapy for groin pain in athletes
<p>Abstract</p> <p>Background</p> <p>Athletes competing in sports that require running, changes in direction, repetitive kicking and physical contact are at a relatively higher risk of experiencing episodes of athletic groin pain. To date, there has been no systematic review that aims to inform clinicians about the best available evidence on features of exercise interventions for groin pain in athletes. The primary aim of this systematic review was to evaluate the available evidence on the effectiveness of exercise therapy for groin pain in athletes. The secondary aim of this review was to identify the key features of exercise interventions used in the management of groin pain in an athletic population.</p> <p>Methods</p> <p>MEDLINE, CINAHL, PubMed, SPORTSDiscus, Embase, AMED, Ovid, PEDro, Cochrane Controlled Trials Register and Google Scholar databases were electronically searched. Data relating to research design, sample population, type of sport and exercise intervention was extracted. The methodological evaluation of included studies was conducted by using a modified quantitative critical appraisal tool.</p> <p>Results</p> <p>The search strategy identified 468 studies, 12 of which were potentially relevant. Ultimately five studies were included in this review. Overall the quality of primary research literature was moderate, with only one randomised controlled trial identified. All included studies provided evidence that an exercise intervention may lead to favourable outcomes in terms of return to sport. Four of the five studies reviewed included a strengthening component and most utilised functional, standing positions similar to those required by their sport. No study appropriately reported the intensity of their exercise interventions. Duration of intervention ranged from 3.8 weeks to 16 weeks. All five studies reported the use of one or more co-intervention.</p> <p>Conclusion</p> <p>Best available evidence to date, with its limitations, continues to support common clinical practice of exercise therapy as a key component of rehabilitation for groin pain in athletes. Overall, the available evidence suggests that exercise, particularly strengthening exercise of the hip and abdominal musculature could be an effective intervention for athletes with groin pain. Literature provides foundational evidence that this may need to be in the form of progressive exercises (static to functional) and performed through range. There is currently no clear evidence regarding the most effective intensity and frequency of exercise, because of a lack of reporting in the primary literature.</p
A Profile Likelihood Analysis of the Constrained MSSM with Genetic Algorithms
The Constrained Minimal Supersymmetric Standard Model (CMSSM) is one of the
simplest and most widely-studied supersymmetric extensions to the standard
model of particle physics. Nevertheless, current data do not sufficiently
constrain the model parameters in a way completely independent of priors,
statistical measures and scanning techniques. We present a new technique for
scanning supersymmetric parameter spaces, optimised for frequentist profile
likelihood analyses and based on Genetic Algorithms. We apply this technique to
the CMSSM, taking into account existing collider and cosmological data in our
global fit. We compare our method to the MultiNest algorithm, an efficient
Bayesian technique, paying particular attention to the best-fit points and
implications for particle masses at the LHC and dark matter searches. Our
global best-fit point lies in the focus point region. We find many
high-likelihood points in both the stau co-annihilation and focus point
regions, including a previously neglected section of the co-annihilation region
at large m_0. We show that there are many high-likelihood points in the CMSSM
parameter space commonly missed by existing scanning techniques, especially at
high masses. This has a significant influence on the derived confidence regions
for parameters and observables, and can dramatically change the entire
statistical inference of such scans.Comment: 47 pages, 8 figures; Fig. 8, Table 7 and more discussions added to
Sec. 3.4.2 in response to referee's comments; accepted for publication in
JHE
Explosive Nucleosynthesis: What we learned and what we still do not understand
This review touches on historical aspects, going back to the early days of
nuclear astrophysics, initiated by BFH and Cameron, discusses (i) the
required nuclear input from reaction rates and decay properties up to the
nuclear equation of state, continues (ii) with the tools to perform
nucleosynthesis calculations and (iii) early parametrized nucleosynthesis
studies, before (iv) reliable stellar models became available for the late
stages of stellar evolution. It passes then through (v) explosive environments
from core-collapse supernovae to explosive events in binary systems (including
type Ia supernovae and compact binary mergers), and finally (vi) discusses the
role of all these nucleosynthesis production sites in the evolution of
galaxies. The focus is put on the comparison of early ideas and present, very
recent, understanding.Comment: 11 pages, to appear in Springer Proceedings in Physics (Proc. of
Intl. Conf. "Nuclei in the Cosmos XV", LNGS Assergi, Italy, June 2018
A randomised control crossover trial of a theory based intervention to improve sun-safe and healthy behaviours in construction workers:Study protocol
Abstract Background Exposure to sunlight can have both positive and negative health impacts. Excessive exposure to ultra-violet (UV) radiation from the sun can cause skin cancer, however insufficient exposure to sunlight has a detrimental effect on production of Vitamin D. In the construction industry there are onsite proactive behaviours for safety, but sun-safety remains a low priority. There is limited research on understanding the barriers to adopting sun-safe behaviours and the association this may have with Vitamin D production. This paper reports a protocol for an intervention study, using text messaging in combination with a supportive smartphone App. The intervention aims to both reduce UV exposure during months with higher UV levels and promote appropriate dietary changes to boost Vitamin D levels during months with low UV levels. Method/design Approximately 60 construction workers will be recruited across the United Kingdom. A randomised control crossover trial (RCCT) will be used to test the intervention, with randomisation at site level â i.e. participants will receive both the control (no text messages or supportive App support) and intervention (daily text messages and supportive App). Using the Theory of Planned Behaviour (TPB) the intervention focuses on supporting sun-safety and healthy dietary decisions in relation to Vitamin D intake. The intervention emphasises cultivating the perception of normative support in the workplace, increasing awareness of control and self-efficacy in taking sun-protective behaviours, making healthier eating choices to boost Vitamin D, and tackling stigmas attached to image and group norms. Each study epoch will last 21Â days with intervention text messages delivered on workdays only. The supportive App will provide supplementary information about sun protective behaviours and healthy dietary choices. The primary outcome measure is 25-hydroxy-Vitamin D [25(OH)D] level (obtained using blood spot sampling), which will be taken pre and post control and intervention periods. Secondary outcome measures are two-fold, (1) using the TPB to detect changes in behaviour, and (2) quantifying UV exposure during the UK peak radiation season (AprilâSeptember) using body-mounted UV sensors. Discussion This study will provide important information about the effectiveness of a technology-based intervention to promote sun-safety and healthy behaviours in outdoor construction workers. Trial registration ISRCTN15888934 retrospectively registered 15.01.2018
A search for the decay modes B+/- to h+/- tau l
We present a search for the lepton flavor violating decay modes B+/- to h+/-
tau l (h= K,pi; l= e,mu) using the BaBar data sample, which corresponds to 472
million BBbar pairs. The search uses events where one B meson is fully
reconstructed in one of several hadronic final states. Using the momenta of the
reconstructed B, h, and l candidates, we are able to fully determine the tau
four-momentum. The resulting tau candidate mass is our main discriminant
against combinatorial background. We see no evidence for B+/- to h+/- tau l
decays and set a 90% confidence level upper limit on each branching fraction at
the level of a few times 10^-5.Comment: 15 pages, 7 figures, submitted to Phys. Rev.
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