1,275 research outputs found
Response of lightning NOx emissions and ozone production to climate change: Insights from the Atmospheric Chemistry and Climate Model Intercomparison Project
Results from an ensemble of models are used to investigate the response of lightning nitrogen oxide emissions to climate change and the consequent impacts on ozone production. Most models generate lightning using a parameterization based on cloud top height. With this approach and a present-day global emission of 5 TgN, we estimate a linear response with respect to changes in global surface temperature of +0.44 ± 0.05 TgN K−1. However, two models using alternative approaches give +0.14 and −0.55 TgN K−1 suggesting that the simulated response is highly dependent on lightning parameterization. Lightning NOx is found to have an ozone production efficiency of 6.5 ± 4.7 times that of surface NOx sources. This wide range of efficiencies across models is partly due to the assumed vertical distribution of the lightning source and partly to the treatment of nonmethane volatile organic compound (NMVOC) chemistry. Careful consideration of the vertical distribution of emissions is needed, given its large influence on ozone production
Munchausen by internet: current research and future directions.
The Internet has revolutionized the health world, enabling self-diagnosis and online support to take place irrespective of time or location. Alongside the positive aspects for an individual's health from making use of the Internet, debate has intensified on how the increasing use of Web technology might have a negative impact on patients, caregivers, and practitioners. One such negative health-related behavior is Munchausen by Internet
Use of Twitter in Neurology: Boon or Bane?
Twitter is a free, open access social media platform that is widely used in medicine by physicians, scientists, and patients. It provides an opportunity for advocacy, education, and collaboration. However, it is likely not utilized to its full advantage by many disciplines in medicine, and pitfalls exist in its use. In particular, there has not been a review of Twitter use and its applications in the field of neurology. This review seeks to provide an understanding of the current use of Twitter in the field of neurology to assist neurologists in engaging with this potentially powerful application to support their work
Full Genome Characterization of the Culicoides-Borne Marsupial Orbiviruses: Wallal Virus, Mudjinbarry Virus and Warrego Viruses
Viruses belonging to the species Wallal virus and Warrego virus of the genus Orbivirus were identified as causative agents of blindness in marsupials in Australia during 1994/5. Recent comparisons of nucleotide (nt) and amino acid (aa) sequences have provided a basis for the grouping and classification of orbivirus isolates. However, full-genome sequence data are not available for representatives of all Orbivirus species. We report full-genome sequence data for three additional orbiviruses: Wallal virus (WALV); Mudjinabarry virus (MUDV) and Warrego virus (WARV). Comparisons of conserved polymerase (Pol), sub-core-shell 'T2' and core-surface 'T13' proteins show that these viruses group with other Culicoides borne orbiviruses, clustering with Eubenangee virus (EUBV), another orbivirus infecting marsupials. WARV shares <70% aa identity in all three conserved proteins (Pol, T2 and T13) with other orbiviruses, consistent with its classification within a distinct Orbivirus species. Although WALV and MUDV share <72.86%/67.93% aa/nt identity with other orbiviruses in Pol, T2 and T13, they share >99%/90% aa/nt identities with each other (consistent with membership of the same virus species - Wallal virus). However, WALV and MUDV share <68% aa identity in their larger outer capsid protein VP2(OC1), consistent with membership of different serotypes within the species - WALV-1 and WALV-2 respectively
Duodenal enteroglucagonoma revealed by differential comparison of serum and tissue glucagon reactivity with Siemens' Double Glucagon Antibody and DakoCytomation's Polyclonal Rabbit Anti-Human Glucagon: a case report
<p>Abstract</p> <p>Introduction</p> <p>This case report demonstrates that the differential immunohistochemical reactivities of Siemens' <it>Double Antibody Glucagon </it>compared to DakoCytomation's <it>Polyclonal Rabbit Anti-Human Glucagon </it>allow for pathologic distinction of enteral versus pancreatic glucagonoma.</p> <p>Case presentation</p> <p>A 64-year-old Caucasian man was diagnosed with a duodenal enteroglucagonoma following presentation with obstructive jaundice. He had a low serum glucagon level using Siemens' <it>Double Antibody Glucagon</it>, a clinical syndrome consistent with glucagon hypersecretion. A periampullary mass biopsy proved to be a neuroendocrine tumor, with positive immunohistochemical reactivity to DakoCytomation's <it>Polyclonal Rabbit Anti-Human Glucagon</it>.</p> <p>Conclusions</p> <p>Differential comparison of the immunohistochemical reactivities of Siemens' <it>Double Antibody Glucagon </it>and DakoCytomation's <it>Polyclonal Rabbit Anti-Human Glucagon </it>discerns enteroglucagon from pancreatic glucagon.</p
Eosinophil and T Cell Markers Predict Functional Decline in COPD Patients
BACKGROUND. The major marker utilized to monitor COPD patients is forced expiratory volume in one second (FEV1). However, asingle measurement of FEV1 cannot reliably predict subsequent decline. Recent studies indicate that T lymphocytes and eosinophils are important determinants of disease stability in COPD. We therefore measured cytokine levels in the lung lavage fluid and plasma of COPD patients in order to determine if the levels of T cell or eosinophil related cytokines were predictive of the future course of the disease. METHODS. Baseline lung lavage and plasma samples were collected from COPD subjects with moderately severe airway obstruction and emphysematous changes on chest CT. The study participants were former smokers who had not had a disease exacerbation within the past six months or used steroids within the past two months. Those subjects who demonstrated stable disease over the following six months (ΔFEV1 % predicted = 4.7 ± 7.2; N = 34) were retrospectively compared with study participants who experienced a rapid decline in lung function (ΔFEV1 % predicted = -16.0 ± 6.0; N = 16) during the same time period and with normal controls (N = 11). Plasma and lung lavage cytokines were measured from clinical samples using the Luminex multiplex kit which enabled the simultaneous measurement of several T cell and eosinophil related cytokines. RESULTS AND DISCUSSION. Stable COPD participants had significantly higher plasma IL-2 levels compared to participants with rapidly progressive COPD (p = 0.04). In contrast, plasma eotaxin-1 levels were significantly lower in stable COPD subjects compared to normal controls (p < 0.03). In addition, lung lavage eotaxin-1 levels were significantly higher in rapidly progressive COPD participants compared to both normal controls (p < 0.02) and stable COPD participants (p < 0.05). CONCLUSION. These findings indicate that IL-2 and eotaxin-1 levels may be important markers of disease stability in advanced emphysema patients. Prospective studies will need to confirm whether measuring IL-2 or eotaxin-1 can identify patients at risk for rapid disease progression.National Heart, Lung, and Blood Institute (NO1-HR-96140, NO1-HR-96141-001, NO1-HR-96144, NO1-HR-96143; NO1-HR-96145; NO1-HR-96142, R01HL086936-03); The Flight Attendant Medical Research Institute; the Jo-Ann F. LeBuhn Center for Chest Diseas
Optimising clonidine dosage for sedation in mechanically ventilated children: a pharmacokinetic simulation study
BACKGROUND: Clonidine is in widespread off-label use as a sedative in mechanically ventilated children, despite limited evidence of efficacy. A variety of dosage regimens have been utilised in clinical practice and in research studies. Within these studies, clonidine has inconsistently shown useful sedation properties. One of the reasons attributed to the inconsistent signs of efficacy is suboptimal clonidine dosing. AIM: This study aims to propose a target plasma concentration and simulate clonidine pharmacokinetics (PK) in a cohort of mechanically ventilated children to evaluate the adequacy of clonidine dosage regimens used in clinical practice and research studies. METHOD: A literature search was undertaken to identify a clonidine PKPD model, from which a target concentration for sedation was defined. Using a previously published PK model the projected plasma concentrations of 692 mechanically ventilated children (demographics taken from a recent study) were generated. Doses from recently published clinical studies were investigated. Adequacy of each regimen to attain therapeutic clonidine plasma concentrations was assessed. RESULTS: A target plasma concentration of above 2 μg/L was proposed. Nine dosage regimens (four intravenous boluses, four intravenous infusions and one nasogastric route boluses) were evaluated ranging from 1μg/kg 8 hourly intravenous boluses to a regimen up to 3μg/kg/hr continuous intravenous infusion. Regimens with a loading dose of 2μg/kg followed by variable continuous infusion of up to 2μg/kg/hr titrated according to sedation score appear most suitable. CONCLUSIONS: The variety of dosage regimens in previous studies of clonidine along with difficulties in the conduct of interventional studies may have contributed to the lack of efficacy data to support its use. Simulations of clonidine plasma concentrations based on known population pharmacokinetic parameters suggest a loading dose followed by higher than current practice maintenance dose infusion is required to achieve adequate steady-state concentrations early in treatment. Further PKPD studies will aid in the determination of the optimal clonidine dosage regimen. This article is protected by copyright. All rights reserved
Correction: Getting evidence into clinical practice: protocol for evaluation of the implementation of a home-based cardiac rehabilitation programme for patients with heart failure.
This is the final version. Available on open access from BMJ Publishing group via the DOI in this recordThe article to which this is the correction is available in ORE at http://hdl.handle.net/10871/121757This is a correction to: Daw P, van Beurden SB, Greaves C, et al. Getting evidence into clinical practice: protocol for evaluation of the implementation of a home- based cardiac rehabilitation programme for patients with heart failure. BMJ Open 2020;10:e036137. doi: 10.1136/ bmjopen-2019-036137. This article was previously published with an error. The paper was linked to an incorrect trial registration number, which has now been remove
Opening a new window to other worlds with spectropolarimetry
A high level of diversity has already been observed among the planets of our
own Solar System. As such, one expects extrasolar planets to present a wide
range of distinctive features, therefore the characterisation of Earth- and
super Earth-like planets is becoming of key importance in scientific research.
The SEARCH (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) mission
proposal of this paper represents one possible approach to realising these
objectives. The mission goals of SEARCH include the detailed characterisation
of a wide variety of exoplanets, ranging from terrestrial planets to gas
giants. More specifically, SEARCH will determine atmospheric properties such as
cloud coverage, surface pressure and atmospheric composition, and may also be
capable of identifying basic surface features. To resolve a planet with a semi
major axis of down to 1.4AU and 30pc distant SEARCH will have a mirror system
consisting of two segments, with elliptical rim, cut out of a parabolic mirror.
This will yield an effective diameter of 9 meters along one axis. A phase mask
coronagraph along with an integral spectrograph will be used to overcome the
contrast ratio of star to planet light. Such a mission would provide invaluable
data on the diversity present in extrasolar planetary systems and much more
could be learned from the similarities and differences compared to our own
Solar System. This would allow our theories of planetary formation, atmospheric
accretion and evolution to be tested, and our understanding of regions such as
the outer limit of the Habitable Zone to be further improved.Comment: 23 pages, accepted for publication in Experimental Astronom
Seladin-1 expression is regulated by promoter methylation in adrenal cancer
<p>Abstract</p> <p>Background</p> <p>Seladin-1 overexpression exerts a protective mechanism against apoptosis. Seladin-1 mRNA is variably expressed in normal human tissues. Adrenal glands show the highest levels of seladin-1 expression, which are significantly reduced in adrenal carcinomas (ACC). Since up to now seladin-1 mutations were not described, we investigated whether promoter methylation could account for the down-regulation of seladin-1 expression in ACC.</p> <p>Methods</p> <p>A methylation sensitive site was identified in the seladin-1 gene. We treated DNA extracted from two ACC cell lines (H295R and SW13) with the demethylating agent 5-Aza-2-deoxycytidine (5-Aza). Furthermore, to evaluate the presence of an epigenetic regulation also 'in vivo', seladin-1 methylation and its mRNA expression were measured in 9 ACC and in 5 normal adrenal glands.</p> <p>Results</p> <p>The treatment of cell lines with 5-Aza induced a significant increase of seladin-1 mRNA expression in H295R (fold increase, F.I. = 1.8; p = 0.02) and SW13 (F.I. = 2.9; p = 0.03). In ACC, methylation density of seladin-1 promoter was higher (2682 ± 686) than in normal adrenal glands (362 ± 97; p = 0.02). Seladin-1 mRNA expression in ACC (1452 ± 196) was significantly lower than in normal adrenal glands (3614 ± 949; p = 0.01).</p> <p>Conclusion</p> <p>On this basis, methylation could be involved in the altered pattern of seladin-1 gene expression in ACC.</p
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