31,139 research outputs found

    Antioxidant and Antitumor Activity of Indonesian Herbal Ingredients

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    The present study was to aimed to evaluated and compare in vitro antioxidant activities of 2 Indonesian herbal ingredients (A and B), determined total phenol content., cytotoxic and apoptosis induction activities on HL-60 cells. These data were providing some useful information for people healthy dietary and the new potential application of natural antioxidant containing food materials in functional foods and also as new cancer therapeutics promising candidates. The parameters were total antioxidant activity, amount of total cytotoxic effect on the growth of human promyelocytic leukemia cells (HL-60). Statistical comparison was perform with Student's t-test at p<0.05. The correlation coefficient (r2) between the parameters tested was established by regression analysis. The scavenging effect of extracts herbal on DPPH radicals increased from 0.3-1.5 mg/ml, where is sample A 14.33% to 64.29% and sample B 9.09% to 57.53% was obtained. High content of total phenol compounds were in sample A (21.72 mg GAE/g), lower amounts were in sample B (17.53 mg GAE/g). Apoptosis of HL-60 cells from the morphological changes side (chromatin condensation). Chromatin condensation, a specific and distinct feature of apoptotic cells, was found in the majority of treated cells. The results indicated that the cell death receptor pathway was involved in the apoptosis induced by Indonesian herbal extracts

    A characterization of positive linear maps and criteria of entanglement for quantum states

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    Let HH and KK be (finite or infinite dimensional) complex Hilbert spaces. A characterization of positive completely bounded normal linear maps from B(H){\mathcal B}(H) into B(K){\mathcal B}(K) is given, which particularly gives a characterization of positive elementary operators including all positive linear maps between matrix algebras. This characterization is then applied give a representation of quantum channels (operations) between infinite-dimensional systems. A necessary and sufficient criterion of separability is give which shows that a state ρ\rho on HKH\otimes K is separable if and only if (ΦI)ρ0(\Phi\otimes I)\rho\geq 0 for all positive finite rank elementary operators Φ\Phi. Examples of NCP and indecomposable positive linear maps are given and are used to recognize some entangled states that cannot be recognized by the PPT criterion and the realignment criterion.Comment: 20 page

    FHL2 regulates hematopoietic stem cell functions under stress conditions.

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    FHL2, a member of the four and one half LIM domain protein family, is a critical transcriptional modulator. Here, we identify FHL2 as a critical regulator of hematopoietic stem cells (HSCs) that is essential for maintaining HSC self-renewal under regenerative stress. We find that Fhl2 loss has limited effects on hematopoiesis under homeostatic conditions. In contrast, Fhl2-null chimeric mice reconstituted with Fhl2-null bone marrow cells developed abnormal hematopoiesis with significantly reduced numbers of HSCs, hematopoietic progenitor cells (HPCs), red blood cells and platelets as well as hemoglobin levels. In addition, HSCs displayed a significantly reduced self-renewal capacity and were skewed toward myeloid lineage differentiation. We find that Fhl2 loss reduces both HSC quiescence and survival in response to regenerative stress, probably as a consequence of Fhl2-loss-mediated downregulation of cyclin-dependent kinase-inhibitors, including p21(Cip) and p27(Kip1). Interestingly, FHL2 is regulated under the control of a tissue-specific promoter in hematopoietic cells and it is downregulated by DNA hypermethylation in the leukemia cell line and primary leukemia cells. Furthermore, we find that downregulation of FHL2 frequently occurs in myelodysplastic syndrome and acute myeloid leukemia patients, raising a possibility that FHL2 downregulation has a role in the pathogenesis of myeloid malignancies

    Analytical solutions of the lattice Boltzmann BGK model

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    Analytical solutions of the two dimensional triangular and square lattice Boltzmann BGK models have been obtained for the plain Poiseuille flow and the plain Couette flow. The analytical solutions are written in terms of the characteristic velocity of the flow, the single relaxation time τ\tau and the lattice spacing. The analytic solutions are the exact representation of these two flows without any approximation.Comment: 10 pages, no postscript figure provide

    Dynamical Symmetry Breaking With a Fourth Generation

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    Adding a fourth generation to the Standard Model and assuming it to be valid up to some cutoff \Lambda, we show that electroweak symmetry is broken by radiative corrections due to the fourth generation. The effects of the fourth generation are isolated using a Lagrangian with a genuine scalar without self-interactions at the classical level. For masses of the fourth generation consistent with electroweak precision data (including the B \rightarrow K \pi\ CP asymmetries) we obtain a Higgs mass of the order of a few hundreds GeV and a cutoff \Lambda\ around 1-2 TeV. We study the reliability of the perturbative treatment used to obtain these results taking into account the running of the Yukawa couplings of the fourth quark generation with the aid of the Renormalization Group (RG) equations, finding similar allowed values for the Higgs mass but a slightly lower cut-off due to the breaking of the perturbative regime. Such low cut-off means that the effects of new physics needed to describe electroweak interactions at energy above \Lambda\ should be measurable at the LHC. We use the minimal supersymmetric extension of the standard model with four generations as an explicit example of models realizing the dynamical electroweak symmetry breaking by radiative corrections and containing new physics. Here, the cutoff is replaced by the masses of the squarks and electroweak symmetry breaking by radiative corrections requires the squark masses to be of the order of 1 TeV.Comment: 20 pages, 7 figures. New section adde

    Stress Relaxation in Entangled Polymer Melts

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    We present an extensive set of simulation results for the stress relaxation in equilibrium and step-strained bead-spring polymer melts. The data allow us to explore the chain dynamics and the shear relaxation modulus, G(t)G(t), into the plateau regime for chains with Z=40Z=40 entanglements and into the terminal relaxation regime for Z=10Z=10. Using the known (Rouse) mobility of unentangled chains and the melt entanglement length determined via the primitive path analysis of the microscopic topological state of our systems, we have performed parameter -free tests of several different tube models. We find excellent agreement for the Likhtman-McLeish theory using the double reptation approximation for constraint release, if we remove the contribution of high-frequency modes to contour length fluctuations of the primitive chain.Comment: 5 pages, 3 figure

    The Backstroke framework for source level reverse computation applied to parallel discrete event simulation

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    This report introduces Backstroke, a new open source framework for the automatic generation of reverse code for functions written in C++. Backstroke enables reverse computation for optimistic parallel discrete event simulations. It is built over the ROSE open- source compiler infrastructure, and handles complex C++ features including pointers and pointer types, arrays, function and method calls, class types. inheritance, polymorphism, virtual functions, abstract classes, templated classes and containers. Backstroke also introduces new program inversion techniques based on advanced compiler analysis tools built into ROSE. We explore and illustrate some of the complex language and semantic issues that arise in generating correct reverse code for C++ functions

    A hard metallic material: Osmium Diboride

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    We calculate the structural and electronic properties of OsB2 using density functional theory with or without taking into account spin-orbit (SO) interaction. Our results show that the bulk modulus with and without SO interaction are 364 and 365 Gpa respectively, both are in good agreement with experiment (365-395 Gpa). The evidence of covalent bonding of Os-B, which plays an important role to form a hard material, is indicated both in charge density, atoms in molecules analysis, and density of states analysis. The good metallicity and hardness of OsB2 might suggest its potential application as hard conductors.Comment: Figures improve

    Distinguishing left- and right-handed molecules by two-step coherent pulses

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    Chiral molecules with broken parity symmetries can be modeled as quantum systems with cyclic-transition structures. By using these novel properties, we design two-step laser pulses to distinguish left- and right-handed molecules from the enantiomers. After the applied pulse drivings, one kind chiral molecules are trapped in coherent population trapping state, while the other ones are pumped to the highest states for ionizations. Then, different chiral molecules can be separated.Comment: 11 pages, 3 figures
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