287 research outputs found
Quantum Correlations Dynamics In Two Coupled Semiconductor InAs Quantum Dots
We investigate the dynamics of quantum discord and concurrence between two
excitonic qubits placed inside two coupled semiconductor quantum dots
independently interacting with dephasing reservoirs. We explore their behavior
against the dimensionless time and the temperature in both Markovian and
non-Markovian environments. Moreover, we analyze the external electric field
effects and the F\"orster interaction effects on these correlations. We show
that, although the quantum correlations amount is strongly influenced by the
variation of the electric field and the F\"orster interaction, their
non-Markovian behavior is still preserved under the variation of these two
parameters. Furthermore, we show that for large values of temperature and
dimensionless time, unlike concurrence which vanishes, nonzero discord can
still be observed.Comment: 15 pages, 12 figure
PHYTOCHEMICAL ANALYSIS, ASSESSMENT OF ANTIPROLIFERATIVE AND FREE RADICAL SCAVENGING ACTIVITY OF MORUS ALBA AND MORUS RUBRA FRUITS
Objective: Mulberry is a nontoxic commonly eaten plant, belongs to the Morus and used in folk medicine in the remedy of dysentery, antiphlogistic, diuretic, expectorant, and antidiabetic. The purpose of this study is to evaluate the antiproliferative and radical scavenging activity of the total alcoholic and successive fractions thereof of Morus alba and Morus rubra fruits. In addition, the chemical composition of the bioactive fractions of each species was investigated.Methods: The antiproliferative potential of 8 extracts on 4 human cancer cell lines, hepatocellular carcinoma (HepG2), Caucasian breast adenocarcinoma (MCF7), prostate (PC3), and colon carcinoma (HCT116) in addition to one normal cell line namely human normal immortalized skin fibroblast cells (BJ1) were carried out. Cell viability was determined using MTT assay. The potency was compared with the reference drug doxorubicin. These extracts were also assayed for 1,1-diphenyl-2-hydrazyl free radical scavenging activities. After saponification of the n-hexane fraction, unsaponifiable matter and fatty acid methyl esters were analyzed by gas liquid chromatography (GLC). The chemical composition of the bioactive fractions was investigated using gas chromatography/mass spectrometry (GC/MS) analysis.Results: All the extracts showed significant free radical scavenging activity dose-dependently. The n-hexane and dichloromethane (DCM) fractions of M. rubra exhibited potent cytotoxic activity on almost cancer cell lines. In the same pattern, ethyl acetate (EtOAc) of M. rubra has moderate cytotoxic activity against all cell lines except HepG2. DCM fraction of M. alba possessed both radical scavenging and high potential antiproliferated activities against HCT116 and MCF7 with inhibitory concentration of 43.9 and 32.3 ĂÂŒg/ml, respectively, while it showed no cytotoxic effect on BJ1. GLC analysis showed the major hydrocarbons in M. alba and M. rubra were heptacosane and docosane, respectively. Sterols were similar in both species but with different ratios and cholesterol was the major one. Palmitic and margaric were the major saturated fatty acid while arachidonic was the major unsaturated fatty acid in both species. GC/MS analysis showed the main compound in DCM fraction of each Morus species was palmitic acid. Furthermore, 1,11-bis-(methoxycarbonyl-ethenyl)-10,2-dihydroxy-cycloeicosane and linolelaidic acid, methyl ester were the main compounds in the EtOAc fraction of each Morus species. Whereas, the main compounds in alcoholic extract of M. alba and M. rubra were methyl-14-methyl-pentadecanoate and 1,2-O-isopropylyidene-4-nonene-1,2,3-triol, respectively.Conclusions: The results observed remarkable biological activity of the successive fractions of M. rubra more than those of M. alba and confirmed its importance as a natural bioactive source. Morus species are good candidates to be promising as possible sources for future antitumor and antioxidants in food and pharmaceutical formulations. The strong activity partly explains the potential effects of Morus species for the treatment of cancer and degenerative diseases caused by free radicals
Peculiar properties of the cluster-cluster interaction induced by the Pauli exclusion principle
Role of the Pauli principle in the formation of both the discrete spectrum
and multi-channel states of the binary nuclear systems composed of clusters is
studied in the Algebraic Version of the resonating-group method. Solutions of
the Hill-Wheeler equations in the discrete representation of a complete basis
of the Pauli-allowed states are discussed for 4He+n, 3H+3H, and 4He+4He binary
systems. An exact treatment of the antisymmetrization effects are shown to
result in either an effective repulsion of the clusters, or their effective
attraction. It also yields a change in the intensity of the centrifugal
potential. Both factors significantly affect the scattering phase behavior.
Special attention is paid to the multi-channel cluster structure 6He+6He as
well as to the difficulties arising in the case when the two clustering
configurations, 6He+6He and 4He+8He, are taken into account simultaneously. In
the latter case the Pauli principle, even in the absence of a potential energy
of the cluster-cluster interaction, leads to the inelastic processes and
secures an existence of both the bound state and resonance in the 12Be compound
nucleus.Comment: 17 pages, 14 figures, 1 table; submitted to Phys.Rev.C Keywords:
light neutron-rich nuclei, cluster model
Quasiclassical Green function in an external field and small-angle scattering
The quasiclassical Green functions of the Dirac and Klein-Gordon equations in
the external electric field are obtained with the first correction taken into
account. The relevant potential is assumed to be localized, while its spherical
symmetry is not required. Using these Green functions, the corresponding wave
functions are found in the approximation similar to the Furry-Sommerfeld-Maue
approximation. It is shown that the quasiclassical Green function does not
coincide with the Green function obtained in the eikonal approximation and has
a wider region of applicability. It is illustrated by the calculation of the
small-angle scattering amplitude for a charged particle and the forward photon
scattering amplitude. For charged particles, the first correction to the
scattering amplitude in the non-spherically symmetric potential is found. This
correction is proportional to the scattering angle. The real part of the
amplitude of forward photon scattering in a screened Coulomb potential is
obtained.Comment: 20 pages, latex, 1 figur
Advances in MetaDL: AAAI 2021 Challenge and Workshop
Algorithms and the Foundations of Software technolog
Effects of broadening and electron overheating in tunnel structures based on metallic clusters
We study the influence of energy levels broadening and electron subsystem
overheating in island electrode (cluster) on current-voltage characteristics of
three-electrode structure. A calculation scheme for broadening effect in
one-dimensional case is suggested. Estimation of broadening is performed for
electron levels in disc-like and spherical gold clusters. Within the
two-temperature model of metallic cluster and by using a size dependence of the
Debye frequency the effective electron temperature as a function of bias
voltage is found approximately. We suggest that the effects of broadening and
electron overheating are responsible for the strong smoothing of
current-voltage curves, which is observed experimentally at low temperatures in
structures based on clusters consisting of accountable number of atoms.Comment: 8 pages, 5 figure
Oral Treatment with Iododiflunisal Delays Hippocampal Amyloid-ÎČ Formation in a Transgenic Mouse Model of Alzheimer's Disease: A Longitudinal in vivo Molecular Imaging Study
Transthyretin (TTR) is a tetrameric, amyloid-ÎČ (AÎČ)-binding protein, which reduces AÎČ toxicity. The TTR/AÎČ interaction can be enhanced by a series of small molecules that stabilize its tetrameric form. Hence, TTR stabilizers might act as disease-modifying drugs in Alzheimer's disease. Objective: We monitored the therapeutic efficacy of two TTR stabilizers, iododiflunisal (IDIF), which acts as small-molecule chaperone of the TTR/AÎČ interaction, and tolcapone, which does not behave as a small-molecule chaperone, in an animal model of Alzheimer's disease using positron emission tomography (PET). Methods: Female mice (AÎČPPswe/PS1A246E/TTR+/-) were divided into 3 groups (n=7 per group): IDIF-treated, tolcapone-treated, and non-treated. The oral treatment (100mg/Kg/day) was started at 5 months of age. Treatment efficacy assessment was based on changes in longitudinal deposition of AÎČ in the hippocampus (HIP) and the cortex (CTX) and determined using PET-[18F]florbetaben. Immunohistochemical analysis was performed at age=14 months. Results: Standard uptake values relative to the cerebellum (SUVr) of [18F]florbetaben in CTX and HIP of non-treated animals progressively increased from age=5 to 11 months and stabilized afterwards. In contrast, [18F]florbetaben uptake in HIP of IDIF-treated animals remained constant between ages=5 and 11 months and significantly increased at 14 months. In the tolcapone-treated group, SUVr progressively increased with time, but at lower rate than in the non-treated group. No significant treatment effect was observed in CTX. Results from immunohistochemistry matched the in vivo data at age=14 months. Conclusion: Our work provides encouraging preliminary results on the ability of small-molecule chaperones to ameliorate AÎČ deposition in certain brain regions
Isolation and Identification Studies on Potential Xylanase Producing Strain Trichoderma sp. WICC F46 Isolated from Tropical Soil
Trichoderma is one of few fungal species of high potential application as bio factory for xylanase production. During last few years increased demand have been observed on the need to isolate high efficient strains from soil sample and to use different microbiological and bioprocess engineering approaches to increase the production yield. In this work, efficient xylanase producer strain was isolated from soil and fully identified using phylogeny analysis. In order to develop an efficient submerged medium for xylanase production, media screening was carried out followed by optimization using one factor at a time (OFAT) method. After optimization of medium composition, the maximal xylanase volumetric production reached 311.71 UmL-1. This medium was composed of corn cob, peptone, magnesium sulphate, calcium chloride, and ammonium sulphate
Number of quantal resonances
Employing the concept of time-delay, a relation is found which counts the
number of quantal resonances supported by a potential. Several simple and
advanced illustrations include a treatment of square-well, Dirac delta barrier,
an interesting physical situation from neutron reflectometry, and the Delta
resonance appearing in the scattering of \pi meson from proton.Comment: 9 pages, 5 figure
Bound, virtual and resonance -matrix poles from the Schr\"odinger equation
A general method, which we call the potential -matrix pole method, is
developed for obtaining the -matrix pole parameters for bound, virtual and
resonant states based on numerical solutions of the Schr\"odinger equation.
This method is well-known for bound states. In this work we generalize it for
resonant and virtual states, although the corresponding solutions increase
exponentially when . Concrete calculations are performed for the
ground and the first excited states of , the resonance
states (, ), low-lying states of and
, and the subthreshold resonances in the proton-proton system. We
also demonstrate that in the case the broad resonances their energy and width
can be found from the fitting of the experimental phase shifts using the
analytical expression for the elastic scattering -matrix. We compare the
-matrix pole and the -matrix for broad resonance in
Comment: 14 pages, 5 figures (figures 3 and 4 consist of two figures each) and
4 table
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