7,501 research outputs found
Variability of the Spectral Energy Distribution of the Blazar S5 0716+714
The emission from blazars is known to be variable at all wavelengths. The
flux variability is often accompanied by spectral changes. Spectral energy
distribution (SED) changes must be associated with changes in the spectra of
emitting electrons and/or the physical parameters of the jet. Meaningful
modeling of blazar broadband spectra is required to understand the extreme
conditions within the emission region. Not only is the broadband SED crucial,
but also information about its variability is needed to understand how the
highest states of emission occur and how they differ from the low states. This
may help in discriminating between models. Here we present the results of our
SED modeling of the blazar S5 0716+714 during various phases of its activity.
The SEDs are classified into different bins depending on the optical brightness
state of the source.Comment: 4 pages, 3 figures, contributed talk presented at the conference
Multifrequency Variability of Blazars, Guangzhou, China, September 22-24,
2010. To appear in Journal of Astrophysics and Astronomy (JAA
Milk-Derived Exosomes and Metabolic Regulation
Exosomes are natural nanoparticles that play an important role in cell-to-cell communication. Communication is achieved through the transfer of cargos, such as microRNAs, from donor to recipient cells and binding of exosomes to cell surface receptors. Exosomes and their cargos are also obtained from dietary sources, such as milk. Exosome and cell glycoproteins are crucial for intestinal uptake. A large fraction of milk exosomes accumulates in the brain, whereas the tissue distribution of microRNA cargos varies among distinct species of microRNA. The fraction of milk exosomes that escapes absorption elicits changes in microbial communities in the gut. Dietary depletion of exosomes and their cargos causes a loss of circulating microRNAs and elicits phenotypes such as loss of cognitive performance, increase in purine metabolites, loss of fecundity, and changes in the immune response. Milk exosomes meet the definition of bioactive food compounds
A Pair of Measures of Rotational Error for Axisymmetric Robot End-Effectors
International audienceThis paper deals with the problem of representing the rotational error of spatial robots with three orientational degrees of freedom (DOF). Typically, the errors on each of three Euler angles defining the orientation of an end-effector are analysed separately. However, this is wrong since an accuracy measure should depend only on the "distance" between the nominal pose and the actual one, and not on the choice of reference frame in which these are represented. Several bi-invariant metrics for rotational error exist but are single-parameter and, by definition, disregard the shape of the robot end-effector. Yet, robot end-effectors are typically axisymmetric. Therefore, we propose a two-parameter measure of rotational errors that is better suited for such robot end-effectors
Metabonomics and Intensive Care
This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency medicine 2016. Other selected articles can be found online at http://www.biomedcentral.com/collections/annualupdate2016. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901
Intra-epithelial neutrophils in paediatric severe asthma are associated with better lung function
BACKGROUND: Neutrophils and IL-17A have been linked mechanistically in models of allergic airways disease and have been associated with asthma severity. However, their role in paediatric asthma is unknown. OBJECTIVES: To investigate the role of neutrophils and the IL-17A pathway in mediating paediatric severe therapy resistant asthma (STRA). METHODS: Children with STRA (n=51, age 12.6 (6 -16.3) years) and non-asthmatic controls (n=15, age 4.75 (1.6-16) years) underwent clinically indicated fiberoptic bronchoscopy, bronchoalveolar lavage (BAL), endobronchial brushings and biopsy. Neutrophils, IL-17A and IL-17RA expressing cells and levels of IL-17A and IL-22 were quantified in BAL and biopsies and related to clinical features. Primary bronchial epithelial cells (PBECs) were stimulated with IL-17A and/or IL-22, with and without Budesonide. RESULTS: Children with STRA had increased intra-epithelial neutrophils, which positively correlated with FEV1 %predicted (r=0.43, p=0.008). Neutrophil-high patients also had better symptom control, despite lower dose maintenance inhaled steroids. Submucosal neutrophils were not increased in STRA. Submucosal and epithelial IL-17A positive cells and BAL IL-17A and IL-22 levels were similar in STRA and controls. However, there were significantly more IL-17RA positive cells in the submucosa and epithelium in children with STRA compared to controls (p=0.001). Stimulation of PBECs with IL-17A enhanced mRNA expression of IL-17RA and increased release of IL-8, even in the presence of Budesonide. CONCLUSIONS: A proportion of children with STRA exhibit increased intra-epithelial airway neutrophilia that correlated with better lung function. STRA was additionally characterised by increased airway IL-17RA expression. These data suggest a potential beneficial rather than adverse role for neutrophils in paediatric severe asthma pathophysiology
The diagnostic performance of novel skin-based in-vivo tests for tuberculosis infection compared with purified protein derivative tuberculin skin tests and blood-based in vitro interferon-γ release assays: a systematic review and meta-analysis
BACKGROUND: Novel skin-based tests for tuberculosis infection might present suitable alternatives to current tests; however, diagnostic performance of new tests compared with the purified protein derivative-tuberculin skin test (TST) or interferon-γ release assays (IGRA) needs systematic assessment. METHODS: In this systematic review and meta-analysis, we searched English (Medline OVID), Chinese (Chinese Biomedical Literature Database and the China National Knowledge Infrastructure), and Russian (e-library) databases from the inception of each database to May 15, 2019, (with updated search of the Russian and English databases on Oct, 20 2020) using terms "ESAT6" OR "CFP10" AND "skin test" AND "Tuberculosis" OR "C-Tb" OR "Diaskintest". We included studies reporting on the performance of index tests alone or compared with a comparator. Inclusion criteria varied according to review objectives and performance outcome, but reporting of test cut-offs for positivity applied to study population was required from all studies. We used a hierarchy of reference standards for tuberculosis infection consistent with the 2020 WHO framework to evaluate diagnostic performance. Two authors independently reviewed the titles and abstracts for English and Chinese (LF and MK) and Russian studies (MK and VN). Study quality was assessed with QUADAS-2. Pooled random-effects estimates are presented when appropriate for total agreement proportion, sensitivity in microbiologically confirmed tuberculosis and specificity in cohorts with low risk of tuberculosis infection. This study is registered with PROSPERO, CRD42019135572. FINDINGS: We identified 1466 original articles, of which 37 (2·5%) studies, including 10 915 individuals (7111 Diaskintest, 2744 C-Tb, 887 EC, 173 DPPD), were included in the qualitative analysis (29 [78%] studies of Diaskintest, five [15%] studies of C-Tb, two [5%] studies of EC-skintest, and one [3%] study of DPPD). 22 (1·5%) studies including 5810 individuals (3143 Diaskintest, 2129 C-Tb, 538 EC-skintest) were included in the quantitative analysis: 15 (68%) of Diaskintest, five (23%) of C-Tb, and two (9%) of EC-skintest. Tested sub-populations included individuals with HIV, children (0-18 years), and individuals exposed to tuberculosis. Studies were heterogeneous with moderate to high risk of bias. Nine head-to-head studies of index test versus TST and IGRA permitted direct comparisons and pooling. In a mixed cohort of people with and without tuberculosis, Diaskintest pooled agreement with IGRA was 87·16% (95% CI 79·47-92·24) and 55·45% (46·08-64·45) with TST-5 mm cut-off (TST5 mm). Diaskintest sensitivity was 91·18% (95% CI 81·72-95·98) compared with 88·24% (78·20-94·01) for TST5 mm, 89·66 (78·83-95·28) for IGRA QuantiFERON, and 90·91% (79·95-96·16) for TSPOT.TB. C-Tb agreement with IGRA in individuals with active tuberculosis was 79·80% (95% CI 76·10-83·07) compared with 78·92% (74·65-82·63) for TST5 mm/15 mm cut-off (TST5 mm/15 mm). TST5/15mm reflects threshold in cohorts that applied stratified cutoffs: 5 mm for HIV-infected, immunocompromised, or BCG-naive individuals, and 15mm for BCG-vaccinated immunocompetent individuals. C-Tb sensitivity was 74·52% (95% CI 70·39-78·25) compared with a sensitivity of 78·18% (67·75-85·94) for TST5 mm/15 mm, and 71·67% (63·44-78·68) for IGRA. Specificity was 97·85% (95% CI 93·96-99·25) for C-Tb versus 93·31% (90·22-95·48) for TST 15 mm cut-off and 99·15% (79·66-99·97) for IGRA. EC-skintest sensitivity was 86·06% (95% CI 82·39-89·07). INTERPRETATION: Novel skin-based tests for tuberculosis infection appear to perform similarly to IGRA or TST; however, study quality varied. Evaluation of test performance, patient-important outcomes, and diagnostic use in current clinical algorithms will inform implementation in key populations. FUNDING: StopTB (New Diagnostics Working Group) and FIND. TRANSLATIONS: For the Chinese and Russian translations of the abstract see Supplementary Materials section
Etiological Profile and Treatment Outcome of Epistaxis at a Tertiary Care Hospital in Northwestern Tanzania: A Prospective Review of 104 Cases.
Epistaxis is the commonest otolaryngological emergency affecting up to 60% of the population in their lifetime, with 6% requiring medical attention. There is paucity of published data regarding the management of epistaxis in Tanzania, especially the study area. This study was conducted to describe the etiological profile and treatment outcome of epistaxis at Bugando Medical Centre, a tertiary care hospital in Northwestern Tanzania. This was a prospective descriptive study of the cases of epistaxis managed at Bugando Medical Centre from January 2008 to December 2010. Data collected were analyzed using SPSS computer software version 15. A total of 104 patients with epistaxis were studied. Males were affected twice more than the females (2.7:1). Their mean age was 32.24 ± 12.54 years (range 4 to 82 years). The modal age group was 31-40 years. The commonest cause of epistaxis was trauma (30.8%) followed by idiopathic (26.9%) and hypertension (17.3%). Anterior nasal bleeding was noted in majority of the patients (88.7%). Non surgical measures such as observation alone (40.4%) and anterior nasal packing (38.5%) were the main intervention methods in 98.1% of cases. Surgical measures mainly intranasal tumor resection was carried out in 1.9% of cases. Arterial ligation and endovascular embolization were not performed. Complication rate was 3.8%. The overall mean of hospital stay was 7.2 ± 1.6 days (range 1 to 24 days). Five patients died giving a mortality rate of 4.8%. Trauma resulting from road traffic crush (RTC) remains the most common etiological factor for epistaxis in our setting. Most cases were successfully managed with conservative (non-surgical) treatment alone and surgical intervention with its potential complications may not be necessary in most cases and should be the last resort. Reducing the incidence of trauma from RTC will reduce the incidence of emergency epistaxis in our centre
Illiteracy, low educational status, and cardiovascular mortality in India
Background: Influence of education, a marker of SES, on cardiovascular disease (CVD) mortality has not been evaluated in low-income countries. To determine influence of education on CVD mortality a cohort study was performed in India. Methods: 148,173 individuals aged ≥ 35 years were recruited in Mumbai during 1991-1997 and followed to ascertain vital status during 1997-2003. Subjects were divided according to educational status into one of the five groups: illiterate, primary school ( ≦ 5 years of formal education), middle school (6-8 years), secondary school (9-10 years) and college (> 10 years). Multivariate analyses using Cox proportional hazard model was performed an
Role of geometrical cues in bone marrow-derived mesenchymal stem cell survival, growth and osteogenic differentiation
Mesenchymal stem cells play a vital role in bone formation process by differentiating into osteoblasts, in a tissue that offers not a flat but a discontinuous three-dimensional (3D) topography in vivo. In order to understand how geometry may be affecting mesenchymal stem cells, this study explored the influence of 3D geometry on mesenchymal stem cell-fate by comparing cell growth, viability and osteogenic potential using monolayer (two-dimensional, 2D) with microsphere (3D) culture systems normalised to surface area. The results suggested lower cell viability and reduced cell growth in 3D. Alkaline phosphatase activity was higher in 3D; however, both collagen and mineral deposition appeared significantly lower in 3D, even after osteogenic supplementation. Also, there were signs of patchy mineralisation in 3D with or without osteogenic supplementation as early as day 7. These results suggest that the convex surfaces on microspheres and inter-particulate porosity may have led to variable cell morphology and fate within the 3D culture. This study provides deeper insights into geometrical regulation of mesenchymal stem cell responses applicable for bone tissue engineering
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