995 resultados para Qinghaosu (QHS) or Artemisinin


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A theoretical approach has been developed to relate the voltage delay transients of the Mg-MnO2 dry cell observed during discharge by two commonly employed modes, viz., (1) at constant current, and (2) across a constant resistance. The approach has been verified by comparison of experimentally obtained transients with those generated from theory. The method may be used to predict the delay parameters of the Mg-MnO2 dry cell under the two modes of discharge and can, in principle, be extended to lithium batteries.

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Oxides of the formula La3LnBaCu5O13+δ (Ln = Nd, Sm, Gd, Dy, or Y) exhibiting metallic resistivity have been prepared and characterized. In the case of yttrium, a composition close to La2Y2BaCu5O13+δ, which is also metallic, could be prepared.

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The steady natural convection flow on a horizontal cone embedded in a saturated porous medium with non-uniform wall temperature/concentration or heat/mass flux and suction/injection has been investigated. Non-similar solutions have been obtained. The nonlinear couple differential equations under boundary layer approximations governing the flow have been numerically solved. The Nusselt and Sherwood numbers are found to depend on the buoyancy forces, suction/injection rates, variation of wall temperature/concentration or heat/mass flux, Lewis number and the non-Darcy parameter.

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Cosmopolitan ideals have been on the philosophical agenda for several millennia but the end of the Cold War started a new discussion on state sovereignty, global democracy, the role of international law and global institutions. The Westphalian state system in practice since the 17th century is transforming and the democracy deficit needs new solutions. An impetus has been the fact that in the present world, an international body representing global citizens does not exist. In this Master’s thesis, the possibility of establishing a world parliament is examined. In a case analysis, 17 models on world parliament from two journals, a volume of essays and two other publications are discussed. Based on general observations, the models are divided into four thematic groups. The models are analyzed with an emphasis on feasible and probable elements. Further, a new scenario with a time frame of thirty years is proposed based on the methodology of normative futures studies, taking special interest in causal relationships and actions leading to change. The scenario presents three gradual steps that each need to be realized before a sustainable world parliament is established. The theoretical framework is based on social constructivism, and changes in international and multi-level governance are examined with the concepts of globalization, democracy and sovereignty. A feasible, desirable and credible world parliament is constituted gradually by implying electoral, democratic and legal measures for members initially from exclusively democratic states, parliamentarians, non-governmental organizations and other groups. The parliament should be located outside the United Nations context, since a new body avoids the problem of inefficiency currently prevailing in the UN. The main objectives of the world parliament are to safeguard peace and international law and to offer legal advice in cases when international law has been violated. A feasible world parliament is advisory in the beginning but it is granted legislative powers in the future. The number of members in the world parliament could also be extended following the example of the EU enlargement process.

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The crystal structures of two ternary metal nucleotide complexes of cobalt, [Co(en)2(H2O)2]-[Co(5?-IMP)2(H2O)4]Cl2·4H2O (1) and [Co(en)2(H2O)2][Co(5?-GMP)2(H2O)4]Cl2·4H2O (2), have been analysed by X-ray diffraction (en = ethylenediamine, 5?-IMP = inosine 5?-monophosphate, and 5?-GMP = guanosine 5?-monophosphate). Both complexes crystallize in the orthorhombic space group C2221 with a= 8.725(1), b= 25.891(5), c= 21.212(5)Å, Z= 4 for (1) and a= 8.733(2), b= 26.169(4), c= 21.288(4)Å, Z= 4 for (2). The structure of (1) was solved by the heavy-atom method, while that of (2) was deduced from (1). The structures were refined to R values of 0.09 and 0.10 for 1 546 and 1 572 reflections for (1) and (2) respectively. The two structures are isomorphous. A novel feature is that the chelate ligand en and the nucleotide are not co-ordinated to the same metal ion. One of the metal ions lying on the two-fold a axis is octahedrally co-ordinated by two chelating en molecules and two water oxygens, while the other on the two-fold b axis is octahedrally co-ordinated by two N(7) atoms of symmetry-related nucleotides in a cis position and four water oxygens. The conformations of the nucleotides are C(2?)-endo, anti, and gauche�gauche. In both (1) and (2) the charge-neutralising chloride ions are disordered in the vacant space between the molecules. These structures bear similarities to the mode of nucleotide co-ordination to PtII complexes of 6-oxopurine nucleotides, which are the proposed models for intrastrand cross-linking in DNA by a metal complex.

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The ternary metal nucleotide complexes [Ni(en)1.3(H2O)1.4(H2O)2][Ni(5?-dGMP)2(en)0.7-(H2O)0.6(H2O)2]·7H2O (1) and [Ni(en)2(H2O)2][Ni(5?-GMP)2(H2O)4]·6H2O (2)(en = ethylenediamine, 5?-dGMP = 2?-deoxyguanosine 5?-monophosphate, 5?-GMP = guanosine 5?-monophosphate) have been prepared and their structures analyzed by X-ray diffraction methods. Both compounds crystallise in the space group C2221 with a= 8.810(1), b= 25.090(4), c= 21.084(1)Å, and Z= 4 for (1) and a= 8.730(1), b= 25.691(4), c= 21.313(5)Å, and Z= 4 for (2). The structures were deduced from the analogous CoIII complexes and refined by full-matrix least-squares methods to final R values of 0.087 and 0.131 for 1 211 and 954 reflections for (1) and (2) respectively. An interesting feature of the deoxyribonucleotide complex (1) is that en is not totally labilized from the metal centre on nucleotide co-ordination, as observed in corresponding ribonucleotide complexes. Apart from extensive intra- and inter-molecular hydrogen bonding, the structures are stabilized by significant intracomplex base�base and base�sugar interactions. The nucleotides in both complexes have an anti base, C(2?)-endo sugar pucker, and gauche�gauche conformation about the C(4?)�C(5?) bond.

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Initiation of follicular growth by specific hormonal stimuli in ovaries of immature rats and hamsters was studied by determining the rate of incorporation of3H-thymidine into ovarian DNAin vitro. Incorporation was considered as an index of DNA synthesis and cell multiplication. A single injection of pregnant mare serum gonadotropin could thus maximally stimulate by 18 hr3H-thymidine incorporation into DNA of the ovary of immature hamsters. Neutralization of pregnant mare serum gonadotropin by an antiserum to ovine follicle stimulating hormone only during the initial 8–10 hr and not later could inhibit the increase in3H-thymidine incorporationin vitro observed at 18 hr, suggesting that the continued presence of gonadotropin stimulus was not necessary for this response. The other indices of follicular growth monitored such as ovarian weight, serum estradiol and uterine weight showed discernible increase at periods only after the above initial event. A single injection of estrogen (diethyl stilbesterol or estradiol-l7β) could similarly cause 18 hr later, a stimulation in the rate of incorporation of3H-thymidine into DNAin vitro in ovaries of immature rats. The presence of endogenous gonadotropins, however, was obligatory for observing this response to estrogen. Evidence in support of the above was two-fold: (i) administration of antiserum to follicle stimulating hormone or luteinizing hormone along with estrogen completely inhibited the increase in3H-thymidine incorporation into ovarian DNAin vitro; (ii) a radioimmunological measurement revealed following estrogen treatment, the presence of a higher concentration of endogenous follicle stimulating hormone in the ovary. Finally, administration of varying doses of ovine follicle stimulating hormone along with a constant dose of estrogen to immature rats produced a dose-dependent increment in the incorporation of3H-thymidine into ovarian DNAin vitro. These observations suggested the potentiality of this system for developing a sensitive bioassay for follicle stimulating hormone.

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A new series of molybdenum cluster compounds of the general formula AxMo5As4(A = Cu, Al, or Ga) has been synthesized. They are isostructural with the host Mo5As4(Ti5Te4-type) consisting of trans-vertex shared Mo6 octahedral chains. Investigations by X-ray photoelectron and Auger electron spectroscopies revealed a charge transfer from A to Mo5As4 in AxMo5As4. The occurrence of metallic (CuxMo5As4) and non-metallic (Al2Mo5As4 and Ga2Mo5As4) properties in this isostructural series of solids is consistent with the electronic structure of Ti5Te4-type solids involving M–M bonding in the cluster chains.

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The effect of neutralizing FSH or LH on ovarian lipids in the cycling hamster was studied. In the normal cycling hamster on the day of proestrus, histochemical examination revealed the presence of sudanophilic lipids in the granulosa cells of the follicles and in the interstitium. A clear reduction in the intensity of lipid staining was observed on proestrus in the ovary of hamsters treated with FSH antiserum on the previous proestrus. Similar treatment with antiserum to LH, on the other hand, caused an accumulation of lipids in these structures. Estimation of the free and esterified fractions of cholesterol and triglycerides in the nonluteal tissue of the ovary of hamsters on proestrus following treatment with FSH antiserum on the previous proestrus revealed a significant reduction in all 3 lipid components. Even a short term deprivation of FSH caused a similar reduction in these lipids in the ovary. In contrast, treatment with LH antiserum either on the previous proestrus or on the previous day (diestrus-2) resulted in an enhancement in esterified cholesterol and triglycerides, while it caused a reduction in the free cholesterol fraction of the ovary on proestrus.It is suggested that though treatment with antisera to either FSH or LH causes a disruption in follicular maturation, their effect on lipid metabolism is different. A positive role for FSH and LH in maintaining normal sterol and triglyceride levels in the nonluteal ovarian tissue of cycling hamster is indicated.

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Following growth doping strategy and using dopant oxides nanocrystals as dopant sources, we report here two different transition-metal ions doped in a variety of group II-VI semiconductor nanocrystals. Using manganese oxide and copper oxide nanocrystals as corresponding dopant sources, intense photoluminescence emission over a wide range of wavelength has been observed for different host nanocrystals. Interestingly, this single doping strategy is successful in providing such highly emissive nanocrystals considered here, in contrast with the literature reports that would suggest synthesis strategies to be highly specific to the particular dopant, host, or both. We investigate and discuss the possible mechanism of the doping process, supporting the migration of dopant ions from dopant oxide nanocrystals to host nanocrystals as the most likely scenario.