2,020 research outputs found
A Protease Isolated from the Latex of Plumeria rubra Linn (Apocynaceae) 2: Anti-inflammatory and Wound- Healing Activities
Purpose: The aim of this study was to investigate the anti-inflammatory and wound-healing activities of the protease isolated from the latex of Plumeria rubra Linn.Methods: The protease was isolated from the latex of the plant by acetone precipitation method and given a trivial name, Plumerin-R. The anti-inflammatory activity of the protease was based on its effects on carrageenan-induced paw oedema in rats. Its wound healing effect was investigated using an excision wound rat model.Results: Four hours after treatment, the reduction in carrageenan-induced rat paw oedema by 20, 40 and 80 mg/kg body weight of plumerin-R was 21.6, 33.8 and 48.8 %, respectively, while oedema reduction by indomethacin (10 mg/kg) was 58.0 %. Plumerin-R showed significant (p < 0.05) wound closure and epithelialization time compared with control.Conclusion: This study demonstrates that the protease, Plumerin-R, has significant anti-inflammatory and wound-healing properties.Keywords: Protease, Plumerin-R, Anti-inflammatory, Excision wound, Healing
Regge behaviour of distribution functions and evolution of gluon distribution function in Next-to-Leading order at low-x
Evolution of gluon distribution function from
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equation in
next-to-leading order (NLO) at low-x is presented assuming the Regge behaviour
of quarks and gluons at this limit. We compare our results of gluon
distribution function with MRST2004, GRV98LO and GRV98NLO parameterizations and
show the compatibility of Regge behaviour of quark and gluon distribution
functions with perturbative quantum chromodynamics (PQCD) at low-x.Comment: 12 pages, 4 figure
Efficient adiabatic demagnetization refrigeration to below 50 mK with UHV compatible Ytterbium diphosphates YbPO (Na, K)
Attaining milli-Kelvin temperatures is often a prerequisite for the study of
novel quantum phenomena and the operation of quantum devices. Adiabatic
demagnetization refrigeration (ADR) is an effective, easy and sustainable
alternative to evaporation or dilution cooling with the rare and
super-expensive He. Paramagnetic salts, traditionally used for mK-ADR,
suffer from chemical instability related to water of crystallization. We report
synthesis, characterization as well as low-temperature magnetization and
specific heat measurements of two new UHV compatible candidate materials
NaYbPO and KYbPO. Utilizing the PPMS at 2 K, the ADR of
sintered pellets with Ag powder admixture starting at 5 T yields base
temperatures (warm-up times) of 45 mK (55 min) and 37 mK (35 min) for
NaYbPO and KYbPO, respectively, slightly advantageous to
KBaYb(BO) (45 mK and 40 min) studied under similar conditions.Comment: 9 pages, 7 figure
Adiabatic demagnetization refrigeration to millikelvin temperatures with the distorted square lattice magnet NaYbGeO4
We report the synthesis, characterization, low-temperature magnetic, and thermodynamic measurements of the millikelvin adiabatic demagnetization refrigeration (mK-ADR) candidate material NaYbGeO4 which exhibits a distorted square lattice arrangement of YbO6 magnetic units. Magnetization and specific heat indicate weakly interacting effective spin-1/2 moments below 10 K, with a Curie-Weiss temperature of only 15 mK, that can be polarized by magnetic fields of order 1 T. For the ADR performance test, we start the demagnetization from 5 T at a temperature of ∼2K and reach a minimum temperature of 150 mK at zero field. The warming curve indicates a sharp magnetic transition in the heat capacity at 210 mK, implying only weak magnetic frustration. The entropy density of SGS≃101 mJK−1cm-3 and hold time below 2 K of 220 min are competitive while the minimal temperature is higher compared to frustrated Ytterbium-oxide ADR materials studied under similar conditions
Quantum decoherence of a charge qubit in a spin-fermion model
We consider quantum decoherence in solid-state systems by studying the
transverse dynamics of a single qubit interacting with a fermionic bath and
driven by external pulses. Our interest is in investigating the extent to which
the lost coherence can be restored by the application of external pulses to the
qubit. We show that the qubit evolution under various pulse sequences can be
mapped onto Keldysh path integrals. This approach allows a simple diagrammatic
treatment of different bath excitation processes contributing to qubit
decoherence. We apply this theory to the evolution of the qubit coupled to the
Andreev fluctuator bath in the context of widely studied superconducting
qubits. We show that charge fluctuations within the Andreev-fluctuator model
lead to a 1/f noise spectrum with a characteristic temperature depedence. We
discuss the strategy for suppression of decoherence by the application of
higher-order (beyond spin echo) pulse sequences.Comment: 7 pages, 4 figures; extended version (accepted to Phys. Rev. B
Entanglement between charge qubits induced by a common dissipative environment
We study entanglement generation between two charge qubits due to the strong
coupling with a common bosonic environment (Ohmic bath). The coupling to the
boson bath is a source of both quantum noise (leading to decoherence) and an
indirect interaction between qubits. As a result, two effects compete as a
function of the coupling strength with the bath: entanglement generation and
charge localization induced by the bath. These two competing effects lead to a
non-monotonic behavior of the concurrence as a function of the coupling
strength with the bath. As an application, we present results for charge qubits
based on double quantum dots.Comment: 9 pages, 7 figure
Cell-specific responses to the cytokine TGFβ are determined by variability in protein levels
The cytokine TGFβ provides important information during embryonic development, adult tissue homeostasis, and regeneration. Alterations in the cellular response to TGFβ are involved in severe human diseases. To understand how cells encode the extracellular input and transmit its information to elicit appropriate responses, we acquired quantitative time-resolved measurements of pathway activation at the single-cell level. We established dynamic time warping to quantitatively compare signaling dynamics of thousands of individual cells and described heterogeneous single-cell responses by mathematical modeling. Our combined experimental and theoretical study revealed that the response to a given dose of TGFβ is determined cell specifically by the levels of defined signaling proteins. This heterogeneity in signaling protein expression leads to decomposition of cells into classes with qualitatively distinct signaling dynamics and phenotypic outcome. Negative feedback regulators promote heterogeneous signaling, as a SMAD7 knock-out specifically affected the signal duration in a subpopulation of cells. Taken together, we propose a quantitative framework that allows predicting and testing sources of cellular signaling heterogeneity
Exchange Instabilities in Semiconductor Double Quantum Well Systems
We consider various exchange-driven electronic instabilities in semiconductor
double-layer systems in the absence of any external magnetic field. We
establish that there is no exchange-driven bilayer to monolayer charge transfer
instability in the double-layer systems. We show that, within the unrestricted
Hartree-Fock approximation, the low density stable phase (even in the absence
of any interlayer tunneling) is a quantum ``pseudospin rotated'' spontaneous
interlayer phase coherent spin-polarized symmetric state rather than the
classical Ising-like charge-transfer phase. The U(1) symmetry of the double
quantum well system is broken spontaneously at this low density quantum phase
transition, and the layer density develops quantum fluctuations even in the
absence of any interlayer tunneling. The phase diagram for the double quantum
well system is calculated in the carrier density--layer separation space, and
the possibility of experimentally observing various quantum phases is
discussed. The situation in the presence of an external electric field is
investigated in some detail using the
spin-polarized-local-density-approximation-based self-consistent technique and
good agreement with existing experimental results is obtained.Comment: 24 pages, figures included. Also available at
http://www-cmg.physics.umd.edu/~lzheng/preprint/ct.uu/ . Revised final
version to appear in PR
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