1,121 research outputs found
Sensitivity of plume descriptors of a Gaussian plume model to deposition and source elevation
Plume descriptors, constituting the first four moments of the concentration distribution, have been obtained for a Gaussian deposition plume model. Analytical expressions for the plume descriptors (centroid, variance, skewness and kurtosis) for point source ground-level and elevated releases are derived from a solution to the
advection-diffusion equation accounting for deposition at the ground surface. A sensitivity analysis has been carried out to investigate the effect of deposition velocity and source height on the plume descriptors. For the particular case of a fully reflected Gaussian plume from a
ground-level source, the centroid and the standard deviation have been found to vary as square root of
downwind distance whereas skewness and kurtosis are independent of downwind distance, the approximate values being 0.995 for skewness and 3.87 for kurtosis
LIBS-Based Detection of Antioxidant Elements in Seeds of Emblica officinalis
The aim of the study was to determine the effect of the elements of the extract of seed from Emblica officinalis on antioxidant enzymes and osmotic fragility of erythrocytes membrane in normal as well as streptozotocin-induced severely diabetic albino Wister rats. The results revealed that the untreated diabetic rats exhibited increase in oxidative stress as indicated by significantly diminished activities of free radical scavenging enzymes such as catalase (CAT) and superoxide dismutase (SOD) by 37.5% (p
Performance evaluation of rice bran biodiesel in small size agricultural diesel engines
India is the second largest rice producing country in the world. The estimated yield of crude Rice Bran Oil (RBO) is about 400,000 tons of which only 50% is of edible grade, 50% of the total available rice bran oil is left unutilized due to the presence of active lipase in bran and lack of economic stabilization methods most of the bran is used as animal feed or for industrial application. One of the best ways for the potential utilization of RBO is the production of biodiesel. This study targets at finding the effects of the engine parameters to compare the performance of diesel and rice bran biodiesel blends. Rice Bran (RB) blends were found to be substitute for diesel fuel. Brake Thermal Efficiency (BTHE) was maximum for RB05 blend and minimum for RB20 blend. RB05 blend can be considered as a substitute for diesel with lower Brake Specific Fuel Consumption (BSFC) and Brake Specific Energy Consumption (BSEC), RB15 was found to have minimum smoke opacity. Keywords: Rice bran oil, Blend, Brake parameters and opacit
Dual-acting stapled peptides target both HIV-1 entry and assembly
Background:
Previously, we reported the conversion of the 12-mer linear and cell-impermeable peptide CAI to a cell-penetrating peptide NYAD-1 by using an i,i + 4 hydrocarbon stapling technique and confirmed its binding to the C-terminal domain (CTD) of the HIV-1 capsid (CA) protein with an improved affinity (Kd ~ 1 μM) compared to CAI (Kd ~ 15 μM). NYAD-1 disrupts the formation of both immature- and mature-like virus particles in in vitro and cell-based assembly assays. In addition, it displays potent anti-HIV-1 activity in cell culture against a range of laboratory-adapted and primary HIV-1 isolates.<p></p>
Results:
In this report, we expanded the study to i,i + 7 hydrocarbon-stapled peptides to delineate their mechanism of action and antiviral activity. We identified three potent inhibitors, NYAD-36, -66 and -67, which showed strong binding to CA in NMR and isothermal titration calorimetry (ITC) studies and disrupted the formation of mature-like particles. They showed typical α-helical structures and penetrated cells; however, the cell penetration was not as efficient as observed with the i,i + 4 peptides. Unlike NYAD-1, the i,i + 7 peptides did not have any effect on virus release; however, they impaired Gag precursor processing. HIV-1 particles produced in the presence of these peptides displayed impaired infectivity. Consistent with an effect on virus entry, selection for viral resistance led to the emergence of two mutations in the gp120 subunit of the viral envelope (Env) glycoprotein, V120Q and A327P, located in the conserved region 1 (C1) and the base of the V3 loop, respectively.<p></p>
Conclusion:
The i,i + 7 stapled peptides derived from CAI unexpectedly target both CA and the V3 loop of gp120. This dual-targeted activity is dependent on their ability to penetrate cells as well as their net charge. This mechanistic revelation will be useful in further modifying these peptides as potent anti-HIV-1 agents.<p></p>
Geometric Phase: a Diagnostic Tool for Entanglement
Using a kinematic approach we show that the non-adiabatic, non-cyclic,
geometric phase corresponding to the radiation emitted by a three level cascade
system provides a sensitive diagnostic tool for determining the entanglement
properties of the two modes of radiation. The nonunitary, noncyclic path in the
state space may be realized through the same control parameters which control
the purity/mixedness and entanglement. We show analytically that the geometric
phase is related to concurrence in certain region of the parameter space. We
further show that the rate of change of the geometric phase reveals its
resilience to fluctuations only for pure Bell type states. Lastly, the
derivative of the geometric phase carries information on both purity/mixedness
and entanglement/separability.Comment: 13 pages 6 figure
Moderate deviations via cumulants
The purpose of the present paper is to establish moderate deviation
principles for a rather general class of random variables fulfilling certain
bounds of the cumulants. We apply a celebrated lemma of the theory of large
deviations probabilities due to Rudzkis, Saulis and Statulevicius. The examples
of random objects we treat include dependency graphs, subgraph-counting
statistics in Erd\H{o}s-R\'enyi random graphs and -statistics. Moreover, we
prove moderate deviation principles for certain statistics appearing in random
matrix theory, namely characteristic polynomials of random unitary matrices as
well as the number of particles in a growing box of random determinantal point
processes like the number of eigenvalues in the GUE or the number of points in
Airy, Bessel, and random point fields.Comment: 24 page
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Developing a coal quality expert: The prediction of ash deposit effects on boiler performance
The overall objective of the Coal Quality Expert (CQE) Clean Coal I Program is the development of a Coal Quality Expert -- a comprehensive PC based expert system for evaluating the potential for coal cleaning, blending and switching options to reduce emissions while producing the lowest cost electricity. A key part of the CQE model will be the development of a sub-model to predict the effects of ash deposition on boiler performance under various operating conditions. To facilitate sub-model development, a combination of full, pilot, and bench scale testing has been carried out on a series of coals and coal blends which were of interest to the Public Service of Oklahoma (PSO) at their Northeastern Station. A series of full-scale tests were also performed on PSO's Northeastern Unit {number sign}4 to characterize boiler performance when firing a baseline coal'' (their normal or desired fuel feed stock) and two blends comprised of the baseline coal blended with various amounts of an alternate coal. Actual furnace conditions were then closely matched during a series of tests performed in Combustion Engineering's pilot scale combustor, the Fireside Performance Test Facility (FPTF). Pilot scale testing allowed in-depth analyses of furnace deposits during and after formation under well-controlled conditions. Ash deposit properties were characterized during pilot scale furnace operation and in subsequent bench scale analyses. Determination of deposit behavior as a function of important operating parameters during the FPTF testing has permitted the prediction of expected performance for various coal/coal blends in PSO's Northeastern Units and allows a prediction of boiler performance for other units firing these fuels
Ebola virus disease: an update on post-exposure prophylaxis
The massive outbreak of Ebola virus disease in west Africa between 2013 and 2016 resulted in intense efforts to evaluate the efficacy of several specific countermeasures developed through years of preclinical work, including the first clinical trials for therapeutics and vaccines. In this Review, we discuss how the experience and data generated from that outbreak have helped to advance the understanding of the use of these countermeasures for post-exposure prophylaxis against Ebola virus infection. In future outbreaks, post-exposure prophylaxis could play an important part in reducing community transmission of Ebola virus by providing more immediate protection than does immunisation as well as providing additional protection for health-care workers who are inadvertently exposed over the course of their work. We propose provisional guidance for use of post-exposure prophylaxis in Ebola virus disease and identify the priorities for future preparedness and further research
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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