204 research outputs found
New Supersymmetric Solutions in N=2 Matter Coupled AdS_3 Supergravities
We construct new 1/2 supersymmetric solutions in D=3, N=2, matter coupled,
U(1) gauged supergravities and study some of their properties. We do this by
employing a quite general supersymmetry breaking condition, from which we also
redrive some of the already known solutions. Among the new solutions, we have
an explicit non-topological soliton for the non-compact sigma model, a locally
flat solution for the compact sigma model and a string-like solution for both
types of sigma models. The last one is smooth for the compact scalar manifold.Comment: 1+21 pages, 2 figures, LaTeX2e, JHEP style; v2: added one reference +
made minor changes and added a few comments to clarify the presentatio
Accelerated Born-Infeld Metrics in Kerr-Schild Geometry
We consider Einstein Born-Infeld theory with a null fluid in Kerr-Schild
Geometry. We find accelerated charge solutions of this theory. Our solutions
reduce to the Plebanski solution when the acceleration vanishes and to the
Bonnor-Vaidya solution as the Born-Infeld parameter b goes to infinity. We also
give the explicit form of the energy flux formula due to the acceleration of
the charged sources.Comment: Latex file (12 pp
Dynamics and stability of the Godel universe
We use covariant techniques to describe the properties of the Godel universe
and then consider its linear response to a variety of perturbations. Against
matter aggregations, we find that the stability of the Godel model depends
primarily upon the presence of gradients in the centrifugal energy, and
secondarily on the equation of state of the fluid. The latter dictates the
behaviour of the model when dealing with homogeneous perturbations. The
vorticity of the perturbed Godel model is found to evolve as in almost-FRW
spacetimes, with some additional directional effects due to shape distortions.
We also consider gravitational-wave perturbations by investigating the
evolution of the magnetic Weyl component. This tensor obeys a simple plane-wave
equation, which argues for the neutral stability of the Godel model against
linear gravity-wave distortions. The implications of the background rotation
for scalar-field Godel cosmologies are also discussed.Comment: Revised version, to match paper published in Class. Quantum Gra
Оцінка оновлення основних засобів за рахунок позикових коштів
Оновлення основних засобів є актуальною проблемою сьогодення. Для багатьох підприємств кредити банків є чи не єдиним джерелом коштів на модернізацію виробничих потужностей. В даній статті нами були розглянуті можливості і перспективи приватних фірм для використання з цією метою позикових засобів, оцінений ступінь прозорості банківських установ, річні ставки за інвестиційними кредитами та інші умови їхнього надання.Modernizing of the basic assets is a topical problem of the present. For many business firms bank loans are may be the only source of funds for renewal of production facilities. In the article we have considered the opportunities and prospects for use of borrowed funds by private firms for this purpose, rated the degree of transparency of banking institutions, the annual rates of investment credits and other conditions of their granting
Methanogens, sulphate and heavy metals: a complex system
Anaerobic digestion (AD) is a well-established technology used for the treatment of wastes and wastewaters with high organic content. During AD organic matter is converted stepwise to methane-containing biogasa renewable energy carrier. Methane production occurs in the last AD step and relies on methanogens, which are rather sensitive to some contaminants commonly found in wastewaters (e.g. heavy metals), or easily outcompeted by other groups of microorganisms (e.g. sulphate reducing bacteria, SRB). This review gives an overview of previous research and pilot-scale studies that shed some light on the effects of sulphate and heavy metals on methanogenesis. Despite the numerous studies on this subject, comparison is not always possible due to differences in the experimental conditions used and parameters explained. An overview of the possible benefits of methanogens and SRB co-habitation is also covered. Small amounts of sulphide produced by SRB can precipitate with metals, neutralising the negative effects of sulphide accumulation and free heavy metals on methanogenesis. Knowledge on how to untangle and balance sulphate reduction and methanogenesis is crucial to take advantage of the potential for the utilisation of biogenic sulphide as a metal detoxification agent with minimal loss in methane production in anaerobic digesters.The research was financially supported by the People Program (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007-2013 under REA agreement 289193
Can the ADO Index Be Used as a Predictor of Mortality from COVID-19 in Patients with COPD?
Esra Ertan Yazar,1 Gulsah Gunluoglu,2 Burcu Arpinar Yigitbas,1 Mukadder Calikoglu,3 Gazi Gulbas,4 Nilgün Yılmaz Demirci,5 Nurhan Sarioglu,6 Fulsen Bozkus,7 Nevin Taci Hoca,5 Nalan Ogan,8 Seda Tural Onur,2 Muzaffer Onur Turan,9 Filiz Kosar,2 Evrim Eylem Akpinar,8 Burak Mete,10 Can Ozturk5 1Department of Chest Diseases, Istanbul Medeniyet University, Medical Faculty, Istanbul, Turkey; 2Department of Chest Diseases, Yedikule Chest Disease and Chest Surgery Research and Training Hospital, Istanbul, Turkey; 3Department of Chest Diseases, Mersin University, Medical Faculty, Mersin, Turkey; 4Department of Chest Diseases, Inonu University, Medical Faculty, Malatya, Turkey; 5Department of Chest Diseases, Gazi University, Medical Faculty, Ankara, Turkey; 6Department of Chest Diseases, Balikesir University, Medical Faculty, Balikesir, Turkey; 7Department of Chest Diseases, Kahramanmaras Sutcu Imam University, Medical Faculty, Kahramanmaras, Turkey; 8Department of Chest Diseases, Ufuk University, Medical Faculty, Ankara, Turkey; 9Department of Chest Diseases, Prof Dr, Izmir Katip Celebi University, Atatürk Research and Training Hospital, Izmir, Turkey; 10Department of Public Health Çukurova University, Medical Faculty, Adana, TurkeyCorrespondence: Esra Ertan Yazar, Istanbul Medeniyet University, Medical Faculty, Department of Chest Diseases, Istanbul, Turkey, Email [email protected]: Several studies have shown that the risk of mortality due to COVID-19 is high in patients with COPD. However, evidence on factors predicting mortality is limited.Research Question: Are there any useful markers to predict mortality in COVID-19 patients with COPD?.Study Design and Methods: A total of 689 patients were included in this study from the COPET study, a national multicenter observational study investigating COPD phenotypes consisting of patients who were followed up with a spirometry-confirmed COPD diagnosis. Patients were also retrospectively examined in terms of COVID-19 and their outcomes.Results: Among the study patients, 105 were diagnosed with PCR-positive COVID-19, and 19 of them died. Body mass index (p= 0.01) and ADO (age, dyspnoea, airflow obstruction) index (p= 0.01) were higher, whereas predicted FEV1 (p< 0.001) and eosinophil count (p= 0.003) were lower in patients who died of COVID-19. Each 0.755 unit increase in the ADO index increased the risk of death by 2.12 times, and each 0.007 unit increase in the eosinophil count decreased the risk of death by 1.007 times. The optimum cut-off ADO score of 3.5 was diagnostic with 94% sensitivity and 40% specificity in predicting mortality.Interpretation: Our study suggested that the ADO index recorded in the stable period in patients with COPD makes a modest contribution to the prediction of mortality due to COVID-19. Further studies are needed to validate the use of the ADO index in estimating mortality in both COVID-19 and other viral respiratory infections in patients with COPD.Keywords: body mass index, COVID-19, eosinophils, FEV1, mortality, pneumonia, pulmonary disease, chronic obstructiv
Spermatogonial stem cell sensitivity to capsaicin: An in vitro study
<p>Abstract</p> <p>Background</p> <p>Conflicting reports have been published on the sensitivity of spermatogenesis to capsaicin (CAP), the pungent ingredient of hot chili peppers. Here, the effect of CAP on germ cell survival was investigated by using two testis germ cell lines as a model. As CAP is a potent agonist of the transient receptor potential vanilloid receptor 1 (TRPV1) and no information was available of its expression in germ cells, we also studied the presence of TRPV1 in the cultured cells and in germ cells in situ.</p> <p>Methods</p> <p>The rat spermatogonial stem cell lines Gc-5spg and Gc-6spg were used to study the effects of different concentrations of CAP during 24 and 48 h. The response to CAP was first monitored by phase-contrast microscopy. As germ cells appear to undergo apoptosis in the presence of CAP, the activation of caspase 3 was studied using an anti activated caspase 3 antibody or by quantifying the amount of cells with DNA fragmentation using flow cytometry. Immunolocalization was done with an anti-TRPV1 antibody either with the use of confocal microscopy to follow live cell labeling (germ cells) or on Bouin fixed paraffin embedded testicular tissues. The expression of TRPV1 by the cell lines and germ cells was confirmed by Western blots.</p> <p>Results</p> <p>Initial morphological observations indicated that CAP at concentrations ranging from 150 uM to 250 uM and after 24 and 48 h of exposure, had deleterious apoptotic-like effects on both cell lines: A large population of the CAP treated cell cultures showed signs of DNA fragmentation and caspase 3 activation. Quantification of the effect demonstrated a significant effect of CAP with doses of 150 uM in the Gc-5spg cell line and 200 uM in the Gc-6spg cell line, after 24 h of exposure. The effect was dose and time dependent in both cell lines. TRPV1, the receptor for CAP, was found to be expressed by the spermatogonial stem cells in vitro and also by premeiotic germ cells in situ.</p> <p>Conclusion</p> <p>CAP adversely affects spermatogonial survival in vitro by inducing apoptosis to those cells and TRPV-1, a CAP receptor, may be involved in this effect as this receptor is expressed by mitotic germ cells.</p
Release of Bet v 1 from birch pollen from 5 European countries. Results from the HIALINE study
Exposure to allergens is pivotal in determining sensitization and allergic symptoms in individuals. Pollen grain counts in ambient air have traditionally been assessed to estimate airborne allergen exposure. However, the exact allergen content of ambient air is unknown. We therefore monitored atmospheric concentrations of birch pollen grains and the matched major birch pollen allergen Bet v 1 simultaneously across Europe within the EU-funded project HIALINE (Health Impacts of Airborne Allergen Information Network). Pollen count was assessed with Hirst type pollen traps at 10 I min(-1) at sites in France, United Kingdom, Germany, Italy and Finland. Allergen concentrations in ambient air were sampled at 800 I min(-1) with a Chemvol (R) high-volume cascade impactor equipped with stages PM > 10 mu m, 10 mu m > PM > 2.5 mu m, and in Germany also 2.5 mu m > PM > 0.12 mu m. The major birch pollen allergen Bet v 1 was determined with an allergen specific ELISA. Bet v 1 isoform patterns were analyzed by 2D-SDS-PAGE blots and mass spectrometric identification. Basophil activation was tested in an FC epsilon R1-humanized rat basophil cell line passively sensitized with serum of a birch pollen symptomatic patient. Compared to 10 previous years, 2009 was a representative birch pollen season for all stations. About 90% of the allergen was found in the PM > 10 mu m fraction at all stations. Bet v 1 isoforms pattern did not vary substantially neither during ripening of pollen nor between different geographical locations. The average European allergen release from birch pollen was 3.2 pg Bet v 1/pollen and did not vary much between the European countries. However, in all countries a >10-fold difference in daily allergen release per pollen was measured which could be explained by long-range transport of pollen with a deviating allergen release. Basophil activation by ambient air extracts correlated better with airborne allergen than with pollen concentration. Although Bet v 1 is a mixture of different isoforms, its fingerprint is constant across Europe. Bet v 1 was also exclusively linked to pollen. Pollen from different days varied >10-fold in allergen release. Thus exposure to allergen is inaccurately monitored by only monitoring birch pollen grains. Indeed, a humanized basophil activation test correlated much better with allergen concentrations in ambient air than with pollen count. Monitoring the allergens themselves together with pollen in ambient air might be an improvement in allergen exposure assessment.European CommissionChristine Kühne - Center for Allergy Research and Educatio
Overview of diagnosis and management of paediatric headache. Part I: diagnosis
Headache is the most common somatic complaint in children and adolescents. The evaluation should include detailed history of children and adolescents completed by detailed general and neurological examinations. Moreover, the possible role of psychological factors, life events and excessively stressful lifestyle in influencing recurrent headache need to be checked. The choice of laboratory tests rests on the differential diagnosis suggested by the history, the character and temporal pattern of the headache, and the physical and neurological examinations. Subjects who have any signs or symptoms of focal/progressive neurological disturbances should be investigated by neuroimaging techniques. The electroencephalogram and other neurophysiological examinations are of limited value in the routine evaluation of headaches. In a primary headache disorder, headache itself is the illness and headache is not attributed to any other disorder (e.g. migraine, tension-type headache, cluster headache and other trigeminal autonomic cephalgias). In secondary headache disorders, headache is the symptom of identifiable structural, metabolic or other abnormality. Red flags include the first or worst headache ever in the life, recent headache onset, increasing severity or frequency, occipital location, awakening from sleep because of headache, headache occurring exclusively in the morning associated with severe vomiting and headache associated with straining. Thus, the differential diagnosis between primary and secondary headaches rests mainly on clinical criteria. A thorough evaluation of headache in children and adolescents is necessary to make the correct diagnosis and initiate treatment, bearing in mind that children with headache are more likely to experience psychosocial adversity and to grow up with an excess of both headache and other physical and psychiatric symptoms and this creates an important healthcare problem for their future life
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