668 research outputs found

    Theory of magnetism with temporal disorder applied to magnetically doped ZnO

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    A dynamic model of the asymmetric Ising glass is presented: an Ising model with antiferromagnet bonds with probabilities q arranged at random in a ferromagnetic matrix. The dynamics is introduced by changing the arrangement of the antiferromagnetic bonds after n Monte Carlo steps but keeping the same value of q and spin configuration. In the region where there is a second order transition between the ferromagnetic and paramagnetic states the dynamic behaviour follows that expected for motional narrowing and reverts to the static behaviour only for large n. There is a different dynamic behaviour where there is a first order transition between the ferromagnetic and spin glass states where it shows no effects of motional narrowing. The implications of this are discussed. This model is devised to explain the properties of doped ZnO where the magnetisation is reduced when the exchange interactions change with time.Comment: Paper was presented at MMM 2008 and is accepted for publication in J.A.

    Draft genome sequence of Methyloferula stellata AR4, an obligate methanotroph possessing only a soluble methane monooxygenase

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    Methyloferula stellata AR4 is an aerobic acidophilic methanotroph, which, in contrast to most known methanotrophs but similar to Methylocella spp., possesses only a soluble methane monooxygenase. However, it differs from Methylocella spp. by its inability to grow on multicarbon substrates. Here, we report the draft genome sequence of this bacterium

    Emergency intubation in trauma in KwaZuluNatal Province South Africa

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    Background. Advanced airway management is a research priority in prehospital care. There is a high burden of major trauma in KwaZulu-Natal (KZN) Province, South Africa (SA), and transfer times to trauma units are often prolonged.Objectives. To examine emergency intubation practice in trauma and burns patients in Pietermaritzburg, KZN, and its environs.Methods. This was a prospective consecutive case series, conducted from 11 May to 17 July 2016. Data were collected from urban emergency department (ED), rural hospital and roadside procedures in Pietermaritzburg and its drainage area. Patients with emergency intubation following trauma were eligible for inclusion. The primary outcome was successful airway management. Secondary outcomes included first-pass success and adverse events.Results. Forty-one cases were recorded in patients aged 1 - 60 years. No instances of unsuccessful airway management were reported. Recorded first-pass intubation success rates were higher in receiving EDs than rural hospitals (19/22 v. 2/7; p=0.003). Use of a formal preintubation checklist was associated with a higher first-pass success rate (21/23 v. 6/15; p=0.001) and fewer adverse events (0/23 v. 7/16; p<0.001). Identified adverse event rates were 1/22 (EDs), 5/8 (rural hospitals) and 2/9 (roadside). Unmedicated intubation was more common in rural hospitals than EDs (3/8 v. 1/22; p=0.019), despite absence of cardiac arrest in these cases. Minimum standards of anaesthetic monitoring were not consistently met in any setting.Conclusions. The use of a preprocedural checklist was associated with improved intubation outcomes and may improve practice in SA trauma care and the prehospital environment, including in rural hospitals. Standardised rapid sequence induction protocols, routine use of introducers and end-tidal carbon dioxide monitoring, and increased availability of intraosseous devices also merit consideration. Key performance indicators should be monitored routinely.Â

    Emergency intubation in trauma in KwaZulu-Natal Province, South Africa

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    Background. Advanced airway management is a research priority in prehospital care. There is a high burden of major trauma in KwaZulu-Natal (KZN) Province, South Africa (SA), and transfer times to trauma units are often prolonged.Objectives. To examine emergency intubation practice in trauma and burns patients in Pietermaritzburg, KZN, and its environs.Methods. This was a prospective consecutive case series, conducted from 11 May to 17 July 2016. Data were collected from urban emergency department (ED), rural hospital and roadside procedures in Pietermaritzburg and its drainage area. Patients with emergency intubation following trauma were eligible for inclusion. The primary outcome was successful airway management. Secondary outcomes included first-pass success and adverse events.Results. Forty-one cases were recorded in patients aged 1 - 60 years. No instances of unsuccessful airway management were reported. Recorded first-pass intubation success rates were higher in receiving EDs than rural hospitals (19/22 v. 2/7; p=0.003). Use of a formal preintubation checklist was associated with a higher first-pass success rate (21/23 v. 6/15; p=0.001) and fewer adverse events (0/23 v. 7/16; p<0.001). Identified adverse event rates were 1/22 (EDs), 5/8 (rural hospitals) and 2/9 (roadside). Unmedicated intubation was more common in rural hospitals than EDs (3/8 v. 1/22; p=0.019), despite absence of cardiac arrest in these cases. Minimum standards of anaesthetic monitoring were not consistently met in any setting.Conclusions. The use of a preprocedural checklist was associated with improved intubation outcomes and may improve practice in SA trauma care and the prehospital environment, including in rural hospitals. Standardised rapid sequence induction protocols, routine use of introducers and end-tidal carbon dioxide monitoring, and increased availability of intraosseous devices also merit consideration. Key performance indicators should be monitored routinely.

    What is the impact of mental health-related stigma on help-seeking? A systematic review of quantitative and qualitative studies

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    Publisher Copyright: Copyright © 2014 Cambridge University Press.Background. Individuals often avoid or delay seeking professional help for mental health problems. Stigma may be a key deterrent to help-seeking but this has not been reviewed systematically. Our systematic review addressed the overarching question: What is the impact of mental health-related stigma on help-seeking for mental health problems? Subquestions were: (a) What is the size and direction of any association between stigma and help-seeking? (b) To what extent is stigma identified as a barrier to help-seeking? (c) What processes underlie the relationship between stigma and help-seeking? (d) Are there population groups for which stigma disproportionately deters help-seeking? Method Five electronic databases were searched from 1980 to 2011 and references of reviews checked. A meta-synthesis of quantitative and qualitative studies, comprising three parallel narrative syntheses and subgroup analyses, was conducted. Results. The review identified 144 studies with 90 189 participants meeting inclusion criteria. The median association between stigma and help-seeking was d = - 0.27, with internalized and treatment stigma being most often associated with reduced help-seeking. Stigma was the fourth highest ranked barrier to help-seeking, with disclosure concerns the most commonly reported stigma barrier. A detailed conceptual model was derived that describes the processes contributing to, and counteracting, the deterrent effect of stigma on help-seeking. Ethnic minorities, youth, men and those in military and health professions were disproportionately deterred by stigma. Conclusions. Stigma has a small- to moderate-sized negative effect on help-seeking. Review findings can be used to help inform the design of interventions to increase help-seeking.Peer reviewe

    Trends in suicide in Scotland 1981 – 1999: age, method and geography

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    BACKGROUND: Male suicide rates continued to increase in Scotland when rates in England and Wales declined. Female rates decreased, but at a slower rate than in England and Wales. Previous work has suggested higher than average rates in some rural areas of Scotland. This paper describes trends in suicide and undetermined death in Scotland by age, gender, geographical area and method for 1981 – 1999. METHODS: Deaths from suicide and undetermined cause in Scotland from 1981 – 1999 were identified using the records of the General Registrar Office. The deaths of people not resident in Scotland were excluded from the analysis. Death rates were calculated by area of residence, age group, gender, and method. Standardised Mortality Ratios (SMRs) and 95% confidence intervals were calculated for rates by geographical area. RESULTS: Male rates of death by suicide and undetermined death increased by 35% between 1981 – 1985 and 1996 – 1999. The largest increases were in the youngest age groups. All age female rates decreased by 7% in the same period, although there were increases in younger female age groups. The commonest methods of suicide in men were hanging, self-poisoning and car exhaust fumes. Hanging in males increased by 96.8% from 45 per million to 89 per million, compared to a 30.7% increase for self-poisoning deaths. In females, the commonest method of suicide was self-poisoning. Female hanging death rates increased in the time period. Male SMRs for 1981 – 1999 were significantly elevated in Western Isles (SMR 138, 95% CI 112 – 171), Highland (135, CI 125 – 147), and Greater Glasgow (120, CI 115 – 125). The female SMR was significantly high only in Greater Glasgow (120, CI 112 – 128). CONCLUSION: All age suicide rates increased in men and decreased in women in Scotland in 1981 – 1999. Previous findings of higher than expected male rates in some rural areas were supported. Rates were also high in Greater Glasgow, one of the most deprived areas of Scotland. There were changes in the methods used, with an increase in hanging deaths in men, and a smaller increase in hanging in women. Altered choice of method may have contributed to the increased male deaths

    Overcoming the Challenges Associated with Image-based Mapping of Small Bodies in Preparation for the OSIRIS-REx Mission to (101955) Bennu

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    The OSIRIS-REx Asteroid Sample Return Mission is the third mission in NASA's New Frontiers Program and is the first U.S. mission to return samples from an asteroid to Earth. The most important decision ahead of the OSIRIS-REx team is the selection of a prime sample-site on the surface of asteroid (101955) Bennu. Mission success hinges on identifying a site that is safe and has regolith that can readily be ingested by the spacecraft's sampling mechanism. To inform this mission-critical decision, the surface of Bennu is mapped using the OSIRIS-REx Camera Suite and the images are used to develop several foundational data products. Acquiring the necessary inputs to these data products requires observational strategies that are defined specifically to overcome the challenges associated with mapping a small irregular body. We present these strategies in the context of assessing candidate sample-sites at Bennu according to a framework of decisions regarding the relative safety, sampleability, and scientific value across the asteroid's surface. To create data products that aid these assessments, we describe the best practices developed by the OSIRIS-REx team for image-based mapping of irregular small bodies. We emphasize the importance of using 3D shape models and the ability to work in body-fixed rectangular coordinates when dealing with planetary surfaces that cannot be uniquely addressed by body-fixed latitude and longitude.Comment: 31 pages, 10 figures, 2 table

    Resuscitation with pre-hospital blood products in adults with trauma-related haemorrhagic shock:the RePHILL RCT

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    Background: The treatment of traumatic haemorrhagic shock has been transformed through better haemorrhage control, use of tranexamic acid and use of blood products. The improved survival seen from these strategies has stimulated an interest in pre-hospital transfusion.Objectives: To determine if the clinical effectiveness of resuscitation with red blood cells and lyophilised plasma was superior to 0.9% saline for improving tissue perfusion and reducing mortality in adults with haemorrhagic shock following major trauma.Design: A multi-centre, allocation concealed, open-label, parallel group, randomised controlled trial (with internal pilot).Setting: The trial was conducted in four civilian pre-hospital critical care services who operated within the National Health Service (NHS) England Major Trauma Networks.Participants: Adults (aged ≥16 years) who had sustained traumatic injuries, were attended by a pre-hospital emergency medical team and were hypotensive (systolic blood pressure &lt;90 mmHg or absence of radial pulse) as a consequence of traumatic haemorrhage were eligible for inclusion. The exclusion criteria were known or apparently &lt;16 years, blood administered on scene prior to the arrival of the RePHILL team, traumatic cardiac arrest where (1) the arrest occurred prior to arrival of the team and/or (2) the primary cause is not hypovolaemia, refusal of blood product administration, known Jehovah’s Witness, pregnancy, isolated head injury without evidence of external haemorrhage, prisoners in the custody of HM Prison and Probation Service.Interventions: Participants were randomised to receive up to either two units each of red blood cells and lyophilised plasma or up to 1 L 0.9% saline. Treatment was administered through the intravenous or intraosseous route.Main outcome measures: The primary outcome was a composite of episode mortality and/or impaired lactate clearance. The secondary outcomes included the individual components of the primary outcome.Results: From 6 December 2016 to 2 January 2021, pre-hospital medical teams randomised 432 participants to red blood cell/lyophilised plasma (n = 209) or 0.9% saline (n = 223) out of a target sample size of 490. Most participants were white (62%), males (82%), median age 38 (interquartile range 26 to 58), involved in a road traffic collision (62%) with severe injuries (median injury severity score 36, interquartile range 25 to 50). Prior to randomisation participants had received on average 430 ml crystalloid fluids and tranexamic acid (90%). The primary outcome occurred in 128/199 (64.3%) of participants randomised to red blood cell/lyophilised plasma and 136/210 (64.8%) randomised to 0.9% saline [adjusted risk difference –0.025% (95% confidence interval –9.0% to 9.0%), p = 0.996]. The event rates for the individual components of the primary outcome, episode mortality and lactate clearance were not statistically different between groups [adjusted average differences −3% (−12% to 7%); p = 0.57 and −5% (−14% to 5%), p = 0.33, respectively].Limitations: Recruitment stopped prematurely due to disruption caused by the COVID-19 pandemic.Future work: Identify the characteristics of patients who may benefit from pre-hospital blood products and whether alternative transfusion regimens are superior to standard care.Conclusions: The trial did not demonstrate that pre-hospital red blood cell/lyophilised plasma resuscitation was superior to 0.9% saline for trauma-related haemorrhagic shock.Trial registration: This trial is registered as ISRCTN62326938.Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Efficacy and Mechanism Evaluation Programme (NIHR award ref: 14/152/14) and is published in full in Efficacy and Mechanism Evaluation; Vol. 11, No. 2. See the NIHR Funding and Awards website for further award information.<br/

    Trace-gas metabolic versatility of the facultative methanotroph Methylocella silvestris

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    The climate-active gas methane is generated both by biological processes and by thermogenic decomposition of fossil organic material, which forms methane and short-chain alkanes, principally ethane, propane and butane1, 2. In addition to natural sources, environments are exposed to anthropogenic inputs of all these gases from oil and gas extraction and distribution. The gases provide carbon and/or energy for a diverse range of microorganisms that can metabolize them in both anoxic3 and oxic zones. Aerobic methanotrophs, which can assimilate methane, have been considered to be entirely distinct from utilizers of short-chain alkanes, and studies of environments exposed to mixtures of methane and multi-carbon alkanes have assumed that disparate groups of microorganisms are responsible for the metabolism of these gases. Here we describe the mechanism by which a single bacterial strain, Methylocella silvestris, can use methane or propane as a carbon and energy source, documenting a methanotroph that can utilize a short-chain alkane as an alternative to methane. Furthermore, during growth on a mixture of these gases, efficient consumption of both gases occurred at the same time. Two soluble di-iron centre monooxygenase (SDIMO) gene clusters were identified and were found to be differentially expressed during bacterial growth on these gases, although both were required for efficient propane utilization. This report of a methanotroph expressing an additional SDIMO that seems to be uniquely involved in short-chain alkane metabolism suggests that such metabolic flexibility may be important in many environments where methane and short-chain alkanes co-occur

    Complete Genome Sequence of the Aerobic Facultative Methanotroph Methylocella tundrae Strain T4

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    Methylocella tundrae T4T is a facultative aerobic methanotroph which was isolated from an acidic tundra wetland and possesses only a soluble methane monooxygenase. The complete genome, which includes two megaplasmids, was sequenced using a combination of Illumina and Nanopore technologies. One of the megaplasmids carries a propane monooxygenase gene cluster
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