246 research outputs found
Modification of classical electron transport due to collisions between electrons and fast ions
A Fokker-Planck model for the interaction of fast ions with the thermal
electrons in a quasi-neutral plasma is developed. When the fast ion population
has a net flux (i.e. the distribution of the fast ions is anisotropic in
velocity space) the electron distribution function is significantly perturbed
from Maxwellian by collisions with the fast ions, even if the fast ion density
is orders of magnitude smaller than the electron density. The Fokker-Planck
model is used to derive classical electron transport equations (a generalized
Ohm's law and a heat flow equation) that include the effects of the
electron-fast ion collisions. It is found that these collisions result in a
current term in the transport equations which can be significant even when
total current is zero. The new transport equations are analyzed in the context
of a number of scenarios including particle heating in ICF and MIF
plasmas and ion beam heating of dense plasmas
Loss of imprinting at the Dlk1-Gtl2 locus caused by insertional mutagenesis in the Gtl2 5' region
BACKGROUND: The Dlk1 and Gtl2 genes define a region of mouse chromosome 12 that is subject to genomic imprinting, the parental allele-specific expression of a gene. Although imprinted genes play important roles in growth and development, the mechanisms by which imprinting is established and maintained are poorly understood. Differentially methylated regions (DMRs), which carry methylation on only one parental allele, are involved in imprinting control at many loci. The Dlk1-Gtl2 region contains three known DMRs, the Dlk1 DMR in the 3' region of Dlk1, the intergenic DMR 15 kb upstream of Gtl2, and the Gtl2 DMR at the Gtl2 promoter. Three mouse models are analyzed here that provide new information about the regulation of Dlk1-Gtl2 imprinting. RESULTS: A previously existing insertional mutation (Gtl2lacZ), and a targeted deletion in which the Gtl2 upstream region was replaced by a Neo cassette (Gtl2Î5'Neo), display partial lethality and dwarfism upon paternal inheritance. Molecular characterization shows that both mutations cause loss of imprinting and changes in expression of the Dlk1, Gtl2 and Meg8/Rian genes. Dlk1 levels are decreased upon paternal inheritance of either mutation, suggesting Dlk1 may be causative for the lethality and dwarfism. Loss of imprinting on the paternal chromosome in both Gtl2lacZ and Gtl2Î5'Neo mice is accompanied by the loss of paternal-specific Gtl2 DMR methylation, while maternal loss of imprinting suggests a previously unknown regulatory role for the maternal Gtl2 DMR. Unexpectedly, when the Neo gene is excised, Gtl2Î5' animals are of normal size, imprinting is unchanged and the Gtl2 DMR is properly methylated. The exogenous DNA sequences integrated upstream of Gtl2 are therefore responsible for the growth and imprinting effects. CONCLUSION: These data provide further evidence for the coregulation of the imprinted Dlk1 and Gtl2 genes, and support a role for Dlk1 as an important neonatal growth factor. The ability of the Gtl2lacZ and Gtl2Î5'Neo mutations to cause long-range changes in imprinting and gene expression suggest that regional imprinting regulatory elements may lie in proximity to the integration site
Physiotherapy Rehabilitation Post Patellar Dislocation (PRePPeD)-protocol for an external pilot randomised controlled trial and qualitative study comparing supervised versus self-managed rehabilitation for people after acute patellar dislocation
Background
Patellar dislocations mainly affect adolescents and young adults. After this injury, patients are usually referred to physiotherapy for exercise-based rehabilitation. Currently, limited high-quality evidence exists to guide rehabilitation practice and treatment outcomes vary. A full-scale trial comparing different rehabilitation approaches would provide high-quality evidence to inform rehabilitation practice. Whether this full-scale trial is feasible is uncertain: the only previous trial that compared exercise-based programmes in this patient population had high loss to follow-up. This study aims to assess the feasibility of conducting a future full-scale trial comparing the clinical and cost-effectiveness of two different rehabilitation approaches for people with an acute patellar dislocation.
Methods
Two-arm parallel external pilot randomised controlled trial and qualitative study. We aim to recruit at least 50 participants agedââ„â14 years with an acute first-time or recurrent patellar dislocation from at least three English National Health Service hospitals. Participants will be randomised 1:1 to supervised rehabilitation (four to six, one-to-one, physiotherapy sessions of advice and prescription of tailored progressive home exercise over a maximum of 6 months) or self-managed rehabilitation (one physiotherapy session of self-management advice, exercise, and provision of self-management materials). Pilot objectives are (1) willingness to be randomised, (2) recruitment rate, (3) retention, (4) intervention adherence, and (5) intervention and follow-up method acceptability to participants assessed through one-to-one semi-structured interviews (maximum 20 participants). Follow-up data will be collected 3, 6, and 9 months after randomisation. Quantitative pilot and clinical outcomes will be numerically summarised, with 95% confidence intervals generated for the pilot outcomes using Wilsonâs and exact Poisson methods as appropriate.
Discussion
This study will assess the feasibility of conducting a full-scale trial comparing supervised versus self-managed rehabilitation for people after acute first-time or recurrent patellar dislocation. This full-scale trialâs results would provide high-quality evidence to guide rehabilitation provision for patients with this injury.
Trial registration
ISRCTN registry ISRCTN14235231. Registered on 09 August 2022
Large scale shell model calculations for odd-odd Mn isotopes
Large scale shell model calculations have been carried out for odd-odd
Mn isotopes in two different model spaces. First set of calculations
have been carried out in full shell valence space with two recently
derived shell interactions namely GXPF1A and KB3G treating Ca
as core. The second set of calculations have been performed in
valence space with the interaction treating Ca as core and
imposing a truncation by allowing up to a total of six particle excitations
from the 0f orbital to the upper orbitals for protons and
from the upper orbitals to the 0g orbital for neutron. For
low-lying states in Mn, the KB3G and GXPF1A both predicts good results
and for Mn, KB3G is much better than GXPF1A. For negative parity and
high-spin positive parity states in both isotopes interaction is
required. Experimental data on Mn is sparse and therefore it is not
possible to make any definite conclusions. More experimental data on negative
parity states is needed to ascertain the importance of 0g and higher
orbitals in neutron rich Mn isotopes.Comment: 5 pages, 4 figures, Submitted to Eur. Phys. J.
Development of an internationally agreed minimal dataset for juvenile dermatomyositis (JDM) for clinical and research use
Background: Juvenile dermatomyositis (JDM) is a rare autoimmune inflammatory disorder associated with significant morbidity and mortality. International collaboration is necessary to better understand the pathogenesis of the disease, response to treatment and long-term outcome. To aid international collaboration, it is essential to have a core set of data that all researchers and clinicians collect in a standardised way for clinical purposes and for research. This should include demographic details, diagnostic data and measures of disease activity, investigations and treatment. Variables in existing clinical registries have been compared to produce a provisional data set for JDM. We now aim to develop this into a consensus-approved minimum core dataset, tested in a wider setting, with the objective of achieving international agreement. Methods/Design: A two-stage bespoke Delphi-process will engage the opinion of a large number of key stakeholders through Email distribution via established international paediatric rheumatology and myositis organisations. This, together with a formalised patient/parent participation process will help inform a consensus meeting of international experts that will utilise a nominal group technique (NGT). The resulting proposed minimal dataset will be tested for feasibility within existing database infrastructures. The developed minimal dataset will be sent to all internationally representative collaborators for final comment. The participants of the expert consensus group will be asked to draw together these comments, ratify and 'sign off' the final minimal dataset. Discussion: An internationally agreed minimal dataset has the potential to significantly enhance collaboration, allow effective communication between groups, provide a minimal standard of care and enable analysis of the largest possible number of JDM patients to provide a greater understanding of this disease. The final approved minimum core dataset could be rapidly incorporated into national and international collaborative efforts, including existing prospective databases, and be available for use in randomised controlled trials and for treatment/protocol comparisons in cohort studies
Gender Differences in Experiences and Expectations of Hemodialysis in a Frail and Seriously Unwell Patient Population.
Surprisingly few studies have explored the experiences of seriously unwell people with kidney disease on hemodialysis therapy: we conducted a mixed-methods study to investigate gender differences in illness experience, symptom burden, treatment considerations or expectations in this cohort. Seriously unwell people on hemodialysis (1-year mortality risk of >20%) at 3 hospital-based units were invited to take part in a structured interview or to complete the same questions independently via a questionnaire. A total of 54 people took part (36 males, 18 females); data analysis was undertaken using a thematic approach. "Desire to keep living" is the most important and basic thought process when starting dialysis. Fear also predominates influencing risk assessment and decision-making. Once fear is managed, there are physical, social, practical and emotional issues to rationalize, but choice only seems possible if shared decision-making is part of the consultation.Gender differences were seen in perceived hopes and expectations of treatment. Males were more likely to prioritize achievement of physical goals, with females prioritizing a wish to feel well. Both genders reported significantly higher symptom scores than their health care provider perceived, however this difference was more marked in females. Dialysis regret existed in >50% of participants and 6 out of 54 (11%) stated that they would have chosen no dialysis at all. Females were more likely to report feeling depressed (  = 0.001). Different genders approach treatment decisions and prioritize treatment expectations differently. Recognizing this will allow personalized care plans to be developed and improve the experiences of seriously unwell people with kidney disease. [Abstract copyright: © 2022 International Society of Nephrology. Published by Elsevier Inc.
The GREAT triggerless total data readout method
Recoil decay tagging (RDT) is a very powerful method for the spectroscopy of exotic nuclei. RDT is a delayed coincidence technique between detectors usually at the target position and at the focal plane of a spectrometer. Such measurements are often limited by dead time. This paper describes a novel triggerless data acquisition method, which is being developed for the Gamma Recoil Electron Alpha Tagging (GREAT) spectrometer, that overcomes this limitation by virtually eliminating dead time. Our solution is a total data readout (TDR) method where all channels run independently and are associated in software to reconstruct events. The TDR method allows all the data from both target position and focal plane to be collected with practically no dead-time losses. Each data word is associated with a timestamp generated from a global 100-MHz clock. Events are then reconstructed in real time in the event builder using temporal and spatial associations defined by the physics of the experimen
e-Consent in UK academic-led clinical trials: current practice, challenges and the need for more evidence
BACKGROUND:
During the COVID-19 pandemic, in-person healthcare visits were reduced. Consequently, trial teams needed to consider implementing remote methods for conducting clinical trials, including e-Consent. Although some clinical trials may have implemented e-Consent prior to the pandemic, anecdotes of uptake for this method increased within academic-led trials. When the increased use of this process emerged, representatives from several large academic clinical trial groups within the UK collaborated to discuss ways in which trialists can learn from one another when implementing e-Consent.
METHODS:
A survey of UKCRC-registered Clinical Trials Units (CTUs) was undertaken in AprilâJune 2021 to understand the implementation of and their views on the use of e-Consent and experiences from the perspectives of systems programmers and quality assurance staff on the use of e-Consent. CTUs not using e-Consent were asked to provide any reasons/barriers (including no suitable trials) and any plans for implementing it in the future. Two events for trialists and patient and public involvement (PPI) representatives were then held to disseminate findings, foster discussion, share experiences and aid in the identification of areas that the academic CTU community felt required more research.
RESULTS:
Thirty-four (64%) of 53 CTUs responded to the survey, with good geographical representation across the UK. Twenty-one (62%) of the responding CTUs had implemented e-Consent in at least one of their trials, across different types of trials, including CTIMPs (Clinical Trial of Investigational Medicinal Product), ATIMPs (Advanced Therapy Medicinal Products) and non-CTIMPs. One hundred ninety-seven participants attended the two workshops for wide-ranging discussions.
CONCLUSION:
e-Consent is increasingly used in academic-led trials, yet uncertainties remain amongst trialists, patients and members of the public. Uncertainties include a lack of formal, practical guidance and a lack of evidence to demonstrate optimal or appropriate methods to use. We strongly encourage trialists to continue to share their own experiences of the implementation of e-Consent
Gender differences in experiences and expectations of haemodialysis in a frail and seriously unwell patient population
Introduction Surprisingly few studies have explored the experiences of seriously unwell people with kidney disease on haemodialysis therapy: we conducted a mixed-methods study to investigate gender differences in illness experience, symptom burden, treatment considerations or expectations in this cohort. Methods Seriously unwell people on haemodialysis (1-year mortality risk of >20%) at three hospital-based units were invited to take part in a structured interview or to complete the same questions independently via a questionnaire. 54 people took part (36 males, 18 females); data analysis was undertaken using a thematic approach. Results âDesire to keep livingâ is the most important and basic thought process when starting dialysis. Fear also predominates influencing risk assessment and decision-making. Once fear is managed, there are physical, social, practical and emotional issues to rationalise, but choice only seems possible if shared decision-making is part of the consultation. Gender differences were seen in perceived hopes and expectations of treatment. Males were more likely to prioritise achievement of physical goals, with females prioritising a wish to feel well. Both genders reported significantly higher symptom scores than their healthcare provider perceived, however this difference was more marked in females. Dialysis regret existed in >50% of participants and 6/54 (11%) stated that they would have chosen no dialysis at all. Females were more likely to report feeling depressed (P=0.001). Conclusion Different genders approach treatment decisions and prioritise treatment expectations differently. Recognising this will allow personalised care plans to be developed and improve the experiences of seriously unwell people with kidney disease
Methodological challenges in online trials: an update and insights from the REACT trial
There has been a growth in the number of web-based trials of web-based interventions, adding to an increasing evidence base for their feasibility and effectiveness. However, there are challenges associated with such trials, which researchers must address. This discussion paper follows the structure of the Down Your Drink trial methodology paper, providing an update from the literature for each key trial parameter (recruitment, registration eligibility checks, consent and participant withdrawal, randomization, engagement with a web-based intervention, retention, data quality and analysis, spamming, cybersquatting, patient and public involvement, and risk management and adverse events), along with our own recommendations based on designing the Relatives Education and Coping Toolkit randomized controlled trial for relatives of people with psychosis or bipolar disorder. The key recommendations outlined here are relevant for future web-based and hybrid trials and studies using iterative development and test models such as the Accelerated Creation-to-Sustainment model, both within general health research and specifically within mental health research for relatives. Researchers should continue to share lessons learned from conducting web-based trials of web-based interventions to benefit future studies
- âŠ