1,484 research outputs found

    A phase II study of neoadjuvant chemotherapy with docetaxel, cisplatin and trastuzumab for T2 breast cancers

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    Preclinical data indicate that the combination of docetaxel, cisplatin and trastuzumab (TCH) may have the potential for clinically significant activity against breast cancers that overexpress the her2/neu gene (HER2). An open-label phase II trial was designed to investigate the response rate and toxicity profile of TCH in breast cancer patients with a primary tumor 2-5 cm in diameter (T2) in its original size. Thirty breast cancer patients with HER2-overexpressing tumors were enrolled. Patients received 6 cycles of docetaxel at 60 mg/m(2) and cisplatin at 50 mg/m(2) given on day 1 and then every 21 days. Trastuzumab was given on day 1, cycle 1 (4 mg/kg), and then continued weekly at 2 mg/kg for 1 year or until disease progression. Tumor measurements were obtained at baseline as well as after 3 and 6 cycles of chemotherapy. We identified 29 breast cancer patients in Taiwan, of whom 13 (44.8%) had pathological complete responses. No cardiac toxicity was observed. Hematologic grade 4 or 3 toxicities were observed in 1 of 28 patients. Non-hematologic grade 4 or 3 toxicities with a reverse pattern were observed in 6 of 29 patients. The results of our study indicate that TCH neoadjuvant chemotherapy is feasible and active in T2 HER2-overexpressing breast cancer patients in terms of pathological complete response rate, complete response, partial response and manageable toxicities

    Experimental pulse technique for the study of microbial kinetics in continuous culture

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    A novel technique was developed for studying the growth kinetics of microorganisms in continuous culture. The method is based on following small perturbations of a chemostat culture by on-line measurement of the dynamic response in oxygen consumption rates. A mathematical model, incorporating microbial kinetics and mass transfer between gas and liquid phases, was applied to interpret the data. Facilitating the use of very small disturbances, the technique is non-disruptive as well as fast and accurate. The technique was used to study the growth kinetics of two cultures, Methylosinus trichosporium OB3b growing on methane, both in the presence and in the absence of copper, and Burkholderia (Pseudomonas) cepacia G4 growing on phenol. Using headspace flushes, gas blocks and liquid substrate pulse experiments, estimates for limiting substrate concentrations, maximum conversion rates Vmax and half saturation constants Ks could rapidly be obtained. For M. trichosporium OB3b it was found that it had a far higher affinity for methane when particulate methane monooxygenase (pMMO) was expressed than when the soluble form (sMMO) was expressed under copper limitation. While for B. cepacia G4 the oxygen consumption pattern during a phenol pulse in the chemostat indicated that phenol was transiently converted to an intermediate (4-hydroxy-2-oxovalerate), so that initially less oxygen was used per mole of phenol.

    Medium-evolved fragmentation functions

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    Medium-induced gluon radiation is usually identified as the dominant dynamical mechanism underling the {\it jet quenching} phenomenon observed in heavy-ion collisions. In its actual implementation, multiple medium-induced gluon emissions are assumed to be independent, leading, in the eikonal approximation, to a Poisson distribution. Here, we introduce a medium term in the splitting probabilities so that both medium and vacuum contributions are included on the same footing in a DGLAP approach. The improvements include energy-momentum conservation at each individual splitting, medium-modified virtuality evolution and a coherent implementation of vacuum and medium splitting probabilities. Noticeably, the usual formalism is recovered when the virtuality and the energy of the parton are very large. This leads to a similar description of the suppression observed in heavy-ion collisions with values of the transport coefficient of the same order as those obtained using the {\it quenching weights}.Comment: LaTeX, 18 pages, 13 figures included using epsfig, uses JHEP3; v2: enlarged discussions, one figure replaced, some references added, final versio

    Uniaxial Phase Transition in Si : Ab initio Calculations

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    Based on a previously proposed thermodynamic analysis, we study the relative stabilities of five Si phases under uniaxial compression using ab initio methods. The five phases are diamond, beta-tin, sh, sc, and hcp structures. The possible phase-transition patterns were investigated by considering the phase transitions between any two chosen phases of the five phases. By analyzing the different conributions to the relative pahse stability, we identified the most important factors in reducing the phase-transition pressures at uniaxial compression. We also show that it is possible to have phase transitions occur only when the phases are under uniaxial compression, in spite of no phase transition when under hydrostatic commpression. Taking all five phases into consideration, the phase diagram at uniaxial compression was constructed for pressures under 20 GPa. The stable phases were found to be diamond, beta-tin and sh structures, i.e. the same as those when under hydrostatic condition. According to the phase diagram, direct phase transition from the diamond to the sh phase is possible if the applied uniaxial pressures, on increasing, satisfy the condition of Px>Pz. Simiilarly, the sh-to-beta-tin transition on increeasing pressures is also possible if the applied uniaxial pressures are varied from the condition of Px>Pz, on which the phase of sh is stable, to that of Px<Pz, on which the beta-tin is stable

    Connected Green function approach to ground state symmetry breaking in Φ1+14\Phi^4_{1+1}-theory

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    Using the cluster expansions for n-point Green functions we derive a closed set of dynamical equations of motion for connected equal-time Green functions by neglecting all connected functions higher than 4th4^{th} order for the λΦ4\lambda \Phi^4-theory in 1+11+1 dimensions. We apply the equations to the investigation of spontaneous ground state symmetry breaking, i.e. to the evaluation of the effective potential at temperature T=0T=0. Within our momentum space discretization we obtain a second order phase transition (in agreement with the Simon-Griffith theorem) and a critical coupling of λcrit/4m2=2.446\lambda_{crit}/4m^2=2.446 as compared to a first order phase transition and λcrit/4m2=2.568\lambda_{crit}/4m^2=2.568 from the Gaussian effective potential approach.Comment: 25 Revtex pages, 5 figures available via fpt from the directory ugi-94-11 of [email protected] as one postscript file (there was a bug in our calculations, all numerical results and figures have changed significantly), ugi-94-1

    Trade uncertainty and the two-step procedure: The choice of numeraire and exact indexation

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    In a small open economy it is optimal to first maximize national income and second choose the best consumption point. The same two-step procedure under (quantitative) uncertainty is suboptimal if one of the goods is used as numéraire. Optimality is restored however, if nominal prices are deflated by the exact price index. Hence there is equivalence between the appropriate two-step procedure and the introduction of a stock market under uncertainty (Diamond 1967) under ideal circumstances

    Dimer coverings on the Sierpinski gasket with possible vacancies on the outmost vertices

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    We present the number of dimers Nd(n)N_d(n) on the Sierpinski gasket SGd(n)SG_d(n) at stage nn with dimension dd equal to two, three, four or five, where one of the outmost vertices is not covered when the number of vertices v(n)v(n) is an odd number. The entropy of absorption of diatomic molecules per site, defined as SSGd=limnlnNd(n)/v(n)S_{SG_d}=\lim_{n \to \infty} \ln N_d(n)/v(n), is calculated to be ln(2)/3\ln(2)/3 exactly for SG2(n)SG_2(n). The numbers of dimers on the generalized Sierpinski gasket SGd,b(n)SG_{d,b}(n) with d=2d=2 and b=3,4,5b=3,4,5 are also obtained exactly. Their entropies are equal to ln(6)/7\ln(6)/7, ln(28)/12\ln(28)/12, ln(200)/18\ln(200)/18, respectively. The upper and lower bounds for the entropy are derived in terms of the results at a certain stage for SGd(n)SG_d(n) with d=3,4,5d=3,4,5. As the difference between these bounds converges quickly to zero as the calculated stage increases, the numerical value of SSGdS_{SG_d} with d=3,4,5d=3,4,5 can be evaluated with more than a hundred significant figures accurate.Comment: 35 pages, 20 figures and 1 tabl

    Anisotropic superconductivity mediated by phonons in layered compounds with weak screening effect

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    Anisotropic pairing interactions mediated by phonons are examined in layer systems. It is shown that the screening effects become weaker when the layer spacing increases. Then the anisotropic components of the pairing interactions increase with the screening length since the momentum dependence changes. As a result, various types of anisotropic superconductivity occur depending on the parameter region. For example, p-wave superconductivity occurs when the short-range part of Coulomb repulsion is strong and the layer spacing is large. Two kinds of inter-layer pairing may occur when the layer spacing is not too large. Although the phonon contribution to the d-wave pairing interaction is weaker than the p-wave interaction, it increases with the layer spacing. Relevance of the present results to organic superconductors, high-T_c cuprates, and Sr_2RuO_4 is discussed.Comment: 8 pages, 5 figures, (Latex, revtex.sty, epsf.sty
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