7,085 research outputs found
Monte Carlo Hamiltonian: Inverse Potential
The Monte Carlo Hamiltonian method developed recently allows to investigate
ground state and low-lying excited states of a quantum system, using Monte
Carlo algorithm with importance sampling. However, conventional MC algorithm
has some difficulties when applying to inverse potentials. We propose to use
effective potential and extrapolation method to solve the problem. We present
examples from the hydrogen system.Comment: To appear in Communications in Theoretical Physic
Enrichment and characterization of a bacteria consortium capable of heterotrophic nitrification and aerobic denitrification at low temperature
Nitrogen removal in wastewater treatment plants is usually severely inhibited under cold temperature. The present study proposes bioaugmentation using psychrotolerant heterotrophic nitrification-aerobic denitrification consortium to enhance nitrogen removal at low temperature. A functional consortium has been successfully enriched by stepped increase in DO concentration. Using this consortium, the specific removal rates of ammonia and nitrate at 10 degrees C reached as high as 3.1 mg N/(g SS h) and 9.6 mg N/ (g SS h), respectively. PCR-DGGE and clone library analysis both indicated a significant reduction in bacterial diversity during enrichment. Phylogenetic analysis based on nearly full-length 16S rRNA genes showed that Alphaproteobacteria. Deltaproteobacteria and particularly Bacteroidetes declined while Gammaproteobacteria (all clustered into Pseudomonas sp.) and Betaproteobacteria (mainly Rhodoferax ferrireducens) became dominant in the enriched consortium. It is likely that Pseudomonas spp. played a major role in nitrification and denitrification, while R. ferrireducens and its relatives utilized nitrate as both electron acceptor and nitrogen source. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000312926400021&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Agricultural EngineeringBiotechnology & Applied MicrobiologyEnergy & FuelsSCI(E)EIPubMed31ARTICLE151-15712
Impact of Decoherence on Internal State Cooling using Optical Frequency Combs
We discuss femtosecond Raman type techniques to control molecular vibrations,
which can be implemented for internal state cooling from Feshbach states with
the use of optical frequency combs with and without modulation. The technique
makes use of multiple two-photon resonances induced by optical frequencies
present in the comb. It provides us with a useful tool to study the details of
molecular dynamics at ultracold temperatures. In our theoretical model we take
into account decoherence in the form of spontaneous emission and collisional
dephasing in order to ascertain an accurate model of the population transfer in
the three-level system. We analyze the effects of odd and even chirps of the
optical frequency comb in the form of sine and cosine functions on the
population transfer. We compare the effects of these chirps to the results
attained with the standard optical frequency comb to see if they increase the
population transfer to the final deeply bound state in the presence of
decoherence. We also analyze the inherent phase relation that takes place owing
to collisional dephasing between molecules in each of the states. This ability
to control the rovibrational states of a molecule with an optical frequency
comb enables us to create a deeply bound ultracold polar molecules from the
Feshbach state.Comment: 10 pages, 6 figure
Uniqueness of signature for simple curves
We propose a topological approach to the problem of determining a curve from its iterated integrals. In particular, we prove that a family of terms in the signature series of a two dimensional closed curve with finite p variation, 1≤p<21≤p<2, are in fact moments of its winding number. This relation allows us to prove that the signature series of a class of simple non-smooth curves uniquely determine the curves. This implies that outside a Chordal SLEκSLEκ null set, where 0<κ≤40<κ≤4, the signature series of curves uniquely determine the curves. Our calculations also enable us to express the Fourier transform of the n-point functions of SLE curves in terms of the expected signature of SLE curves. Although the techniques used in this article are deterministic, the results provide a platform for studying SLE curves through the signatures of their sample paths
Cryptotanshinone Induces Apoptosis of HL-60 Cells via Mitochondrial Pathway
Purpose: To test the effect of Cryptotanshinone (CPT), a natural compound isolated from the plant Salvia miltiorrhiza Bunge, on human leukemic cell lines (HL-60).Methods: HL-60 cells were treated with CPT. Cell growth inhibition (%) was quantitated using MTT assay. Apoptosis detection with Annexin V-FITC/propidium iodide staining was followed by flow cytometry. Caspase-3, caspase-8, and caspase-9 colorimetric assay kit was used to determine caspase protease activity. Loss of mitochondrial membrane potential was examined by flow cytometry with JC-1 staining. Bax, PARP, p53, p21 and cytochrome C were determined using Western blot.Results: Morphologic assessment, Annexin V-FITC/propidium iodide staining results and sub-G1 percentage indicate that the cytotoxic effect of CPT was mediated by induction of apoptosis. Furthermore, increased Bax expression, decreased Bcl-2 expression, loss of mitochondria membranepotential (MMP), release of cytochrome C, activation of caspase enzyme, cleavage of PARP and accumulation of p53 and p21 were detected during the apoptotic process. Caspase inhibitor partially abrogated CPT-induced apoptosis.Conclusion: The results show that CPT induced apoptosis of HL-60 cell lines by mitochondria pathway, and suggest that CPT may serve as a potential therapy for leukemia.Keywords: Cryptotanshinone, Salvia miltiorrhiza Bunge, Caspase, Membrane potential, Mitochondrial, Apoptosis, Leukemia, Cytochrome C, Cell cycl
Multi-epoch analysis of the X-ray spectrum of the active galactic nucleus in NGC 5506
We present a multi-epoch X-ray spectroscopy analysis of the nearby
narrow-line Seyfert I galaxy NGC 5506. For the first time, spectra taken by
Chandra, XMM-Newton, Suzaku, and NuSTAR - covering the 2000-2014 time span -
are analyzed simultaneously, using state-of-the-art models to describe
reprocessing of the primary continuum by optical thick matter in the AGN
environment. The main goal of our study is determining the spin of the
supermassive black hole (SMBH). The nuclear X-ray spectrum is photoelectrically
absorbed by matter with column density cm. A
soft excess is present at energies lower than the photoelectric cut-off. Both
photo-ionized and collisionally ionized components are required to fit it. This
component is constant over the time-scales probed by our data. The spectrum at
energies higher than 2 keV is variable. We propose that its evolution could be
driven by flux-dependent changes in the geometry of the innermost regions of
the accretion disk. The black hole spin in NGC 5506 is constrained to be
0.93 at 90% confidence level for one interesting
parameter.Comment: 13 pages, 9 figures. v2: refereed versio
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