464 research outputs found

    EXTENDED MODELLING AND NUMERICAL INVESTIGATION OF PHASED ARRAY SYNTHETIC JET CROSS-FLOW INTERACTIONS

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    A classical analysis of incompressible unsteady Navier-Stokes equation have been under discussion for a long time by various reasearchers, it has been found that the exact analytical unique solution existed only below and undefined Reynolds number limit. Several solutions were existed for a range of Reynolds number above the limit, and that has no solution exsisted above the second undefined Reynolds number (i.e, solution enter into turbulent region and one has to solve another set of equations for turbulance). A useful study was done for two dimensional unsteady incompressible flow in which vorticity is propotional to stream function perturbed by uniform stream. Recently this unsteady sloution was used to analyse the flow behaviour on flat plate using Synthetic Jet Actuators (SJA) which consists of oscillating membrane expels in fluid through orifice. The results obtained at different time level were presented and it was found as the time progresses streamlines, on the flat plate with number of actuators placed in an array, become flatter caused rapidly decay in vortices on trailing edge. The authentication of these results were needded to be validated through experiment or numerical simulation. In this paper, an attempt has been made to solve incompressible unsteady Navier-Stokes equations numerically to analyse the behaviour of single and multiple sythetic jet actuator in a cross flow conditions. The behaviour of SJA implemented by imposing a special kind of boundary condition on the bottom of flate plate was studied. Results have been obtained for various Reynolds numbers and were presented. These numerical results were in close agreement with [1]

    One-pion transitions between heavy baryons in the constituent quark model

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    Single pion transitions of S wave to S wave, P wave to S wave and P wave to P wave heavy baryons are analyzed in the framework of the Heavy Quark Symmetry limit (HQS). We use a constituent quark model picture for the light diquark system with an underlying SU(2N_{f}) X O(3) symmetry to reduce the number of the HQS coupling factors required to describe these transitions. We also use the quantum theory of angular momentum to rewrite the one-pion transitions constituent quark model results in a more general form using the 6j- and 9j-symbols. We finally estimate the decay rates of some single pion transitions between charm baryon states.Comment: Latex, 33 pages including 2 figures (Postscript). Some typos are corrected with minor changes. Two references were added to the final version which will appear in Phy. Rev.

    Growth inhibitory and adjuvant therapeutic potential of aqueous extract of Triticum aestivum on MCF-7 and HeLa cells

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    Aim: The purpose of the present study is to evaluate the potent growth inhibitory effects of aqueous wheatgrass extract (AWE) alone and in combination with cisplatin on human breast and cervical cancer cells. Materials and Methods: The cytotoxic potential of AWE alone and in combination with cisplatin was evaluated on human breast and cervical cancer cells (MCF-7 and HeLa) by cell viability assay. Further, the mode of cell death induced by AWE was determined by nuclear morphological examination and cell cycle analysis. These effects were then correlated with the expression of genes involved in apoptosis and proliferation (cyclin D1 and Bax) by RT-PCR. Results: AWE showed dose- and time dependent selective cytotoxicity towards the cancerhighlighting its safe profile. Lower dose combinations of AWE and cisplatin induced increased growth inhibition compared with the individual drugs on both cell lines (combination index < 1) indicating strong synergistic interactions. AWE was found to induce apoptosis and arrested the cells at G0–G1 phase of the cell cycle which correlated with the modulation of expression of bax and cyclin D1 in a time-dependent manner in MCF-7 and HeLa cells. Conclusion: These results suggest that the anti-cancer potential of AWE may be due to apoptosis induction and its anti-proliferative properties. This study also provides the first evidence demonstrating synergism between AWE and cisplatin, which may enhance the therapeutic index of prevention and/or treatment of human breast and cervical cancer. Key Words: Bax, cisplatin, combination, cyclin D1, synergistic, wheatgrass

    Unparticle physics effects in (Lambda_b -> Lambda + missing energy) processes

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    We study unparticle physics effects in (Lambda_b -> Lambda + missing energy) decay with polarized Λb\Lambda_b and Λ\Lambda baryons. The sensitivity of the branching ratio of this decay and polarizations of (Lambda_b) and (Lambda) baryons on the scale dimension d_U and effective cut-off parameter (Lambda_U) are discussed.Comment: 17 pages, 6 figure

    Nonleptonic Weak Decays of Bottom Baryons

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    Cabibbo-allowed two-body hadronic weak decays of bottom baryons are analyzed. Contrary to the charmed baryon sector, many channels of bottom baryon decays proceed only through the external or internal W-emission diagrams. Moreover, W-exchange is likely to be suppressed in the bottom baryon sector. Consequently, the factorization approach suffices to describe most of the Cabibbo-allowed bottom baryon decays. We use the nonrelativistic quark model to evaluate heavy-to-heavy and heavy-to-light baryon form factors at zero recoil. When applied to the heavy quark limit, the quark model results do satisfy all the constraints imposed by heavy quark symmetry. The decay rates and up-down asymmetries for bottom baryons decaying into (1/2)++P(V)(1/2)^++P(V) and (3/2)++P(V)(3/2)^++P(V) are calculated. It is found that the up-down asymmetry is negative except for Ωb(1/2)++P(V)\Omega_b \to (1/2)^++P(V) decay and for decay modes with ψ\psi' in the final state. The prediction B(ΛbJ/ψΛ)=1.6×104B(\Lambda_b \to J/\psi\Lambda)=1.6 \times 10^{-4} for Vcb=0.038|V_{cb}|=0.038 is consistent with the recent CDF measurement. We also present estimates for Ωc(3/2)++P(V)\Omega_c \to (3/2)^++P(V) decays and compare with various model calculations.Comment: 24 pages, to appear in Phys. Rev. Uncertainties with form factor q^2 dependence are discusse

    Ward Identities, B-> \rho Form Factors and |V_ub|

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    The exclusive FCNC beauty semileptonic decay B-> \rho is studied using Ward identities in a general vector meson dominance framework, predicting vector meson couplings involved. The long distance contributions are discussed which results to obtain form factors and |V_ub|. A detailed comparison is given with other approaches.Comment: 30 pages+four postscript figures, an Appendix adde

    Department of Defense prostate cancer clinical trials consortium: A new instrument for prostate cancer clinical research

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    Background: In 2005, the US Department of Defense, through the US Army Medical Research and Materiel Command, Office of the Congressionally Directed Medical Research Programs, created a funding mechanism to form a clinical trials consortium to conduct phase I and II studies in prostate cancer. This is the first report of the Prostate Cancer Clinical Trials Consortium (PCCTC). Patients and Methods: The Department of Defense award supports a consortium of 10 prostate cancer research centers. Memorial Sloan-Kettering Cancer Center was awarded the Coordinating Center grant for the consortium and charged with creating an infrastructure to conduct early-phase multicenter clinical trials. Each participating center was required to introduce ≥ 1 clinical trial per year and maintain accrual of a minimum of 35 patients per year. Results: The PCCTC was launched in 2006 and now encompasses 10 leading prostate cancer research centers. Fifty-one trials have been opened, and 1386 patients have been accrued at member sites. Members share an online clinical trial management system for protocol tracking, electronic data capture, and data storage. A legal framework has been instituted, and standard operating procedures, an administrative structure, editorial support, centralized budgeting, and mechanisms for scientific review are established. Conclusion: The PCCTC fulfills a congressional directive to create a clinical trials instrument dedicated to early-phase prostate cancer studies. The member institutions have built an administrative, informatics, legal, financial, statistical, and scientific infrastructure to support this endeavor. Clinical trials are open and accruing in excess of federally mandated goals

    Leptonic and Semileptonic Decays of Charm and Bottom Hadrons

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    We review the experimental measurements and theoretical descriptions of leptonic and semileptonic decays of particles containing a single heavy quark, either charm or bottom. Measurements of bottom semileptonic decays are used to determine the magnitudes of two fundamental parameters of the standard model, the Cabibbo-Kobayashi-Maskawa matrix elements VcbV_{cb} and VubV_{ub}. These parameters are connected with the physics of quark flavor and mass, and they have important implications for the breakdown of CP symmetry. To extract precise values of Vcb|V_{cb}| and Vub|V_{ub}| from measurements, however, requires a good understanding of the decay dynamics. Measurements of both charm and bottom decay distributions provide information on the interactions governing these processes. The underlying weak transition in each case is relatively simple, but the strong interactions that bind the quarks into hadrons introduce complications. We also discuss new theoretical approaches, especially heavy-quark effective theory and lattice QCD, which are providing insights and predictions now being tested by experiment. An international effort at many laboratories will rapidly advance knowledge of this physics during the next decade.Comment: This review article will be published in Reviews of Modern Physics in the fall, 1995. This file contains only the abstract and the table of contents. The full 168-page document including 47 figures is available at http://charm.physics.ucsb.edu/papers/slrevtex.p
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