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Physical Studies of Some Hydrazinobenzoic Acid Complexes

Journal of materials Science & Technology 2005年第1期21卷 140-144页

作者： m.G.Abd el Wahed S.Abd el Wanees m.el gamel S.Abd el Haleem Faculty of Science Zagazig University Zagazig EgyptFaculty of Science Zagazig University Zagazig EgyptFaculty of Science Zagazig University Zagazig EgyptFaculty of Science Zagazig University Zagazig Egypt

The stability constants of complexes of 2-hydrazinobenzoic acid and 4-hydrazinobenzoic acid with Ni (Ⅱ), Cu (Ⅱ), Zn (Ⅱ), Cd (Ⅱ), and Hg (Ⅱ) were determined potentiometricaIly at different temperatures. The thermodynamic parameters, △G0, △H0, and △S0 were calculated and proved that the complexation process is spontaneous and endothermic. The thermodynamic functions were analyzed in terms of electrostatic and non-electrostatic components and the results reveal that ionic bonds are formed between the studied ligands and metal ions. Conductometric titration was shown that the stoichiometry of the formed complexes are m:L and m:2L. The structure of the prepared solid complexes was characterized using IR, 1H NmR, 13C NmR spectroscopies as well as X-ray diffraction technique. Finally electrical conductivity of the ligands and their copper complexes was measured and shown that the ligands have a semiconductor behaviour.

关键词： Potentiometric titration Stability constants Thermodynamic parameters Structure of metal complexes

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Two Very Accurate and Efficient methods for Solving Time-Dependent Problems

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Applied mathematics 2018年第11期9卷 1270-1280页

作者： mohamed el-gamel Waleed Adel m. S. el-Azab Department of mathematical Sciences Faculty of Engineering Mansoura University Mansoura Egypt

In this paper, collocation method based on Bernoulli and Galerkin method based on wavelet are proposed for solving nonhomogeneous heat and wave equations. The two methods have the linear systems solved by suitable sol... 详细信息

关键词： Wavelet Galerkin Daubechies Bernoulli Collocation

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Parametric Cure model versus Proportional Hazards model in Survival Analysis of Breast Cancer and Other malignancies

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Advances in Breast Cancer Research 2013年第4期2卷 119-125页

作者： Shunzo maetani John W. gamel Department of Ophthalmology University of Louisvill Louisville USA Tenri Institute of medical Research Tenri Japan

As cancer therapy has progressed dramatically, its goal has shifted toward cure of the disease (curative therapy) rather than prolongation of time to death (life-prolonging therapy). Consequently, the proportion of cured patients (c) has become an important measure of the long-term survival benefit derived from therapy. In 1949, Boag addressed this issue by developing the parametric log-normal cure model, which provides estimates of c and m where m is the mean of log times to death from cancer among uncured patients. Unfortunately, traditional methods based on the proportional hazards model like the Cox regression and log-rank tests cannot provide an estimate of either c or m. Rather, these methods estimate only the differences in hazard between two or more groups. In order to evaluate the long-term validity and usefulness of the parametric cure model compared with the proportional hazards model, we reappraised randomized controlled trials and simulation studies of breast cancer and other malignancies. The results reveal that: 1) the traditional methods fail to distinguish between curative and life-prolonging therapies;2) in certain clinical settings, these methods may favor life-prolonging treatment over curative treatment, giving clinicians a false estimate of the best regimen;3) although the Boag model is less sensitive to differences in failure time when follow-up is limited, it gains power as more failures occur. In conclusion, unless the disease is always fatal, the primary measure of survival benefit should be c rather than m or hazard ratio. Thus, the Boag lognormal cure model provides more accurate and more useful insight into the long-term benefit of cancer treatment than the traditional alternatives.

关键词： Cancer Survival Analysis Boag model Cox model Cure

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