447 research outputs found
Increased sample asymmetry and memory of cardiac time-series following endotoxin administration in cirrhotic rats
Sepsis, and other causes of acute systemic inflammation, can reduce heart rate variability (HRV) and increase cardiac cycle regularity in mammals. Thus, HRV monitoring has been used for early detection of sepsis in adults and neonates. Liver cirrhosis is associated with reduced basal HRV and the development of tolerance to the cardiac chronotropic effects of bacterial endotoxin. This may pose limitations on the use of heart rate monitoring in early detection of sepsis in this patient population. In a study to develop a physiomarker for the detection of sepsis in cirrhosis, we observed that endotoxin administration in adult cirrhotic rats leads to the development of transient heart rate decelerations, a phenomenon which has been reported in neonates with sepsis, and quantified using sample asymmetry analysis. In the present study, cirrhosis was induced by surgical ligation of the bile duct in rats. Cirrhotic rats were given intraperitoneal injections of either saline or endotoxin (1 mg kg(-1)). Changes in sample asymmetry and memory length of cardiac time-series were studied in conscious rats using implanted telemetric probes. Cirrhotic (but not control) rats exhibited increased sample asymmetry following endotoxin injection, which was consistent with the development of transient heart rate deceleration. Endotoxin administration in cirrhotic rats was associated with prolongation of memory length for observing decelerating perturbations in the cardiac rhythm. These findings may have application in the development of an HRV monitoring system for early detection of sepsis in cirrhosis
Constraints on the Persistent Radio Source Associated with FRB 20190520B Using the European VLBI Network
We present very long baseline interferometry (VLBI) observations of a continuum radio source potentially associated with the fast radio burst source FRB 20190520B. Using the European VLBI network, we find the source to be compact on VLBI scales with an angular size of <2.3 mas (3σ). This corresponds to a transverse physical size of <9 pc (at the z = 0.241 redshift of the host galaxy), confirming it to be as fast radio burst (FRB) persistent radio source (PRS) like that associated with the first-known repeater FRB 20121102A. The PRS has a flux density of 201 ± 34 μJy at 1.7 GHz and a spectral radio luminosity of L1.7 GHz = (3.0 ± 0.5) × 1029 erg s−1 Hz−1 (also similar to the FRB 20121102A PRS). Compared to previous lower-resolution observations, we find that no flux is resolved out on milliarcsecond scales. We have refined the PRS position, improving its precision by an order of magnitude compared to previous results. We also report the detection of the FRB 20190520B burst at 1.4 GHz and find the burst position to be consistent with the PRS position, at ≲20 mas. This strongly supports their direct physical association and the hypothesis that a single central engine powers both the bursts and the PRS. We discuss the model of a magnetar in a wind nebula and present an allowed parameter space for its age and the radius of the putative nebula powering the observed PRS emission. Alternatively, we find that an accretion-powered hypernebula model also fits our observational constraints
The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/VIRGO GW170817. VII. Properties of the Host Galaxy and Constraints on the Merger Timescale
We present the properties of NGC 4993, the host galaxy of GW170817, the first
gravitational wave (GW) event from the merger of a binary neutron star (BNS)
system and the first with an electromagnetic (EM) counterpart. We use both
archival photometry and new optical/near-IR imaging and spectroscopy, together
with stellar population synthesis models to infer the global properties of the
host galaxy. We infer a star formation history peaked at Gyr ago,
with subsequent exponential decline leading to a low current star formation
rate of 0.01 M yr, which we convert into a binary merger
timescale probability distribution. We find a median merger timescale of
Gyr, with a 90% confidence range of Gyr. This
in turn indicates an initial binary separation of R,
comparable to the inferred values for Galactic BNS systems. We also use new and
archival images to measure a projected offset of
the optical counterpart of kpc (0.64) from the center of NGC 4993
and to place a limit of mag on any pre-existing emission,
which rules out the brighter half of the globular cluster luminosity function.
Finally, the age and offset of the system indicates it experienced a modest
natal kick with an upper limit of km s. Future GWEM
observations of BNS mergers will enable measurement of their population delay
time distribution, which will directly inform their viability as the dominant
source of -process enrichment in the Universe.Comment: 9 Pages, 3 Figures, 2 Tables, ApJL, In Press. Keywords: GW170817, LV
Epitope Prediction by Novel Immunoinformatics Approach: A State-of-the-art Review
Immunoinformatics is a science that helps to create significant immunological information using bioinformatics softwares and applications. One of the most important applications of immunoinformatics is the prediction of a variety of specific epitopes for B cell recognition and T cell through MHC class I and II molecules. This method reduces costs and time compared to laboratory tests. In this state-of-the-art review, we review about 50 papers to find the latest and most used immunoinformatic tools as well as their applications for predicting the viral, bacterial and tumoral structural and linear epitopes of B and T cells. In the clinic, the main application of prediction of epitopes is for designing peptide-based vaccines. Peptide-based vaccines are a considerably potential alternative to low-cost vaccines that may reduce the risks related to the production of common vaccines. © 2019, Springer Nature B.V
Local perceptions of mental health in Iran, Semnan Province
Introduction: Understanding local perceptions of mental health in different cultures and contexts is crucial for designing and implementing appropriate mental healthcare services. Methods: This qualitative study was conducted to investigate local perceptions of mental health in two highly populated provincial districts in Iran. Data were collected using the free list technique and interviews. A two-phase training workshop was held with the research team at a local health center, followed by a pilot study with the participation of six subjects. All the interviews were audio-recorded, transcribed, and then analyzed by the third and fourth authors in DEDOOSE. Results: A total of 30 individuals (20 in the free list and 10 as key informants in the interviews) took part in the study. Based on the study findings and the key informants' ideas, mental health problems were categorized into three categories of depression, anxiety, and obsessive�compulsive disorder (OCD). Conclusions: Mental health problems appear to be expressed in different ways and with different symptoms in different cultures, and there is a distinct need for examining mental disorders in each culture and nationality separately using culturally appropriate tools for disease screening. © 2020 The Authors. Brain and Behavior published by Wiley Periodicals LL
Electrodeposition and Capacitive Behavior of Films for Electrodes of Electrochemical Supercapacitors
Polypyrrole films were deposited by anodic electropolymerization on stainless steel substrates from aqueous pyrrole solutions containing sodium salicylate and tiron additives. The deposition yield was studied under galvanostatic conditions. The amount of the deposited material was varied by the variation of deposition time at a constant current density. SEM studies showed the formation of porous films with thicknesses in the range of 0–3 μm. Cyclic voltammetry data for the films tested in 0.5 M Na2SO4 solutions showed capacitive behavior and high specific capacitance (SC) in a voltage window of 0.9 V. The films prepared from pyrrole solutions containing tiron showed better capacitive behavior compared to the films prepared from the solutions containing sodium salicylate. A highest SC of 254 F g−1 was observed for the sample with a specific mass of 89 μg cm−2 at a scan rate of 2 mV s−1. The SC decreased with an increasing film thickness and scan rate. The results indicated that the polypyrrole films deposited on the stainless steel substrates by anodic electropolymerization can be used as electrodes for electrochemical supercapacitors (ES)
Thermal plasma synthesis of Li2S nanoparticles for application in lithium-sulfur batteries
Abstract : Inductively-coupled thermal plasma processes were used to produce nanosized Li2S. Prior to the syntheses, the feasibility of forming Li2S was first evaluated using FactSage by considering the phase diagrams of sulfur and different lithium precursors in reducing atmospheres; Li2O, LiOH·H2O, Li2CO3 and Li2SO4·H2O all showed promises in producing Li2S nanoparticles, as confirmed by experiments. Argon and hydrogen mixtures were used as plasma gases, and a carbothermal reduction was implemented for Li2SO4·H2O. In addition, carbon-coated Li2S nanoparticles were synthesized with downstream injection of methane. Carbon was shown to stabilize Li2S upon contact with ambient air. The Li2S nanoparticles were electrochemically tested in half-cells using electrolytes containing LiNO3 or Li2S6 as additives. It was found that adding LiNO3 to the electrolyte was detrimental to the electrochemical performance of Li2S, whereas the combination of Li2S6 and LiNO3 as additives doubled the charge and discharge capacities of the half-cell over 10 cycles
Brain perfusion imaging with voxel-based analysis in secondary progressive multiple sclerosis patients with a moderate to severe stage of disease: a boon for the workforce
Background: The present study was carried out to evaluate cerebral perfusion in multiple sclerosis (MS) patients
with a moderate to severe stage of disease. Some patients underwent hyperbaric oxygen therapy (HBOT) and brain
perfusion between before and after that was compared.
Methods: We retrospectively reviewed 25 secondary progressive (SP)-MS patients from the hospital database.
Neurological disability evaluated by Expanded Disability Status Scale Score (EDSS). Brain perfusion was performed
by (99 m) Tc-labeled bicisate (ECD) brain SPECT and the data were compared using statistical parametric mapping
(SPM). In total, 16 patients underwent HBOT. Before HBOT and at the end of 20 sessions of oxygen treatment,
99mTc-ECD brain perfusion single photon emission computed tomography (SPECT) was performed again then
the results were evaluated and compared. Brain perfusion was performed by (99 m) Tc-labeled bicisate (ECD) brain
SPECT and the data were compared using statistical parametric mapping (SPM).
Results: A total of 25 SP-MS patients, 14 females (56 %) and 11 males (44 %) with a mean age of 38.92 ± 11.
28 years included in the study. The mean disease duration was 8.70 ± 5.30 years. Of the 25 patients, 2 (8 %) had
a normal SPECT and 23 (92 %) had abnormal brain perfusion SPECT studies. The study showed a significant
association between severity of perfusion impairment with disease duration and also with EDSS (P <0.05). There
was a significant improvement in pre- and post-treatment perfusion scans (P <0.05), but this did not demonstrate
a significant improvement in the clinical subjective and objective evaluation of patients (P >0.05).
Conclusions: This study depicted decreased cerebral perfusion in SP-MS patients with a moderate to severe
disability score and its association with clinical parameters. Because of its accessibility, rather low price, practical
ease, and being objective quantitative information, brain perfusion SPECT can be complementing to other
diagnostic modalities such as MRI and clinical examinations in disease surveillance and monitoring. The literature
on this important issue is extremely scarce, and follow up studies are required to assess these preliminary results
Evaluating the Anti-Leech Effects of Methanolic Extracts of Peganum harmala L. and Olea europaea L. on Limnatis nilotica. World's Vet
ABSTRACT Leeches had several complications such as pain, itching, inflammation, severe anemia, short-term bleeding, hypersensitivity, and anaphylactic reactions in their hosts. Harmal Peganum harmala L. is used as an analgesic and anti-inflammatory agent and it has antibacterial activity. Olive Olea europaea L. has antibacterial, anti-viral, hypoglycemic and the relaxation of blood vessels properties. Antioxidant properties of olive also had been reported. This study was carried out to detect the effects of methanolic extracts of P. harmala L. and O. europaea L. on L. nilotica immature form. In 2011, 55 immature leeches collected from the southern area of Ilam province were prepared. The methanolic extract of O. europaea L and P. harmala L. were compared with levamisole as the control drug. Distilled water was evaluated as the placebo group which investigated L. nilotica using anti-leech assay. Then extract and drugs were added and their effects were screened for 720 min and time to paralyze, kill and death of each leech was recorded. The results showed that olive methanolic extractions (600 and 300mg) could kill the leeches in an average time of 145±77.57 and171±33.28 min, respectively. An average death time for levamisole was found to be 15±7.49 min. The highest effectiveness was found for levamisole at dose 300 mg. Methanol extracts of the Harmal (300 and 600 μg/m) and springs water showed no anti-leech. In sum, olive plant could use for anti Limnatis nilotica expenditure
Reversal of diastereoselectivity in the synthesis of Peptidomimetic 3‑Carboxamide-1,4-benzodiazepin-5-ones
Enantiopure 3-carboxamide-1,4-benzodiazepin-5-ones were synthesized via the Ugi reaction followed by the Staudinger/aza-Wittig or reduction reactions in only two steps. A complete reversal of diastereoselectivity was achieved depending on the cyclization methodology employed. The different orientation of the C3 substituent in our 3-substituted 1,4-benzodiazepin-5-ones with respect to the most studied 1,4-benzodiazepin-2-ones makes them complementary in the development of new drugs because the primary source of binding selectivity of 1,4-benzodiazepines is the selective recognition of ligand conformations by the receptor.Ministerio de Economía y Competitividad, Spain (Project CTQ2012-31611), Junta de Castilla y León, Consejería de Educación y Cultura y Fondo Social Europeo (Project BU246A12-1) and the European Commission, Seventh Framework Programme (Project SNIFFER FP7-SEC-2012-312411)
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