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Soumitra Sengupta 《Pramana》1999,53(6):1115-1119
In a space-time with torsion, the action for the gravitational field can be extended with a parity-violating piece. We show how to obtain such a piece from geometry itself, by suitably modifying the affine connection so as to include a pseudo-tensorial part. A consistent method is thus suggested for incorporating parity-violation in the Lagrangians of all matter fields with spin in a space-time background with torsion.  相似文献   
95.
Aristolindiquinone (1) , the first naturally occurring 8-methyl-juglone earlier isolated from Aristolochia indica has been synthesised from o-allyl-p-cresol in 7% overall yield.  相似文献   
96.
Manganese-incorporated ZnS (MnxZn1-xS) nanorods were synthesized by a simple solvothermal process. Synthesized nanorods were single crystalline. Manganese incorporation in the ZnS lattice induces a phase transformation from hexagonal wurtzite to cubic zinc blende structure. The diameter of the nanorods increased with the increase of Mn concentration. Intense orange luminescence at approximately 585 nm was observed for the nanorods. Six-line hyperfine splitting was observed in the EPR spectra for lower Mn concentrations, whereas broad Lorentzian-shaped EPR spectra were obtained for higher Mn concentrations because of the Mn-Mn cluster formation at higher Mn concentrations.  相似文献   
97.
Summary Ni(acac)2 · (H2O)2 (1 mol) and alkali metal fluorides (4 mols), MF (M=NH4, Na or K), react with an excess of 40% HF on a steam-bath. The product upon treatment with water gives light green crystalline alkali metal trifluoronickelate(II) monohydrate, MNiF3 · H2O in a high yield. Chemical analyses, pyrolysis at 120 °C, i.r. spectroscopic, and cryomagnetic (300–80 K) data have been used to characterise, and establish the identity of the compounds. While NH4NiF3 · H2O behaves as a normal octahedral nickel(II) compound, NaNiF3 · H2O is ferromagnetic with Curie point 145 K, KNiF3 · H2O behaves antiferromagnetically; its Neel point is 230 K.  相似文献   
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The reactions of Cp2>HfCl2> with hydrazones (LH) derived from acetylferrocene and aromatic acid hydrazides (benzoic, 2-chlorobenzoic, 3-nitrobenzoic and 4-toluic) in various stoichiometric ratios have been studied and the complexes of the types [Cp2>Hf(L)Cl] and [CpHf(L)3>] were obtained. Tentative structural conclusions are drawn for the reaction products based upon elemental analyses, electrical conductance, magnetic moment and spectral data (u.v.–vis, i.r., 1>H-n.m.r. and 13>C-n.m.r.). Studies were conducted to assess the growth-inhibiting potential of the complexes synthesized, and the ligands, against various fungal and bacterial strains.  相似文献   
99.
A novel approach to the construction of the functionalized core structure of the anticancer diterpene umbellactal is described using a domino metathesis protocol involving ROM-RCM of an appropriately constructed norbornene derivative.  相似文献   
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A solvent responsive dynamic nanoscale metal‐organic framework (NMOF) [Zn( 1 a )(H2O)2] has been devised based on the self‐assembly of ZnII and asymmetric bola‐amphiphilic oligo‐(p‐phenyleneethynylene) (OPE) dicarboxylate linker 1 a having dodecyl and triethyleneglycolmonomethylether (TEG, polar) side chains. In THF solvent, NMOF showed nanovesicular morphology ( NMOF‐1 ) with surface decorated dodecyl chains. In water and methanol, NMOF exhibited inverse‐nanovesicle ( NMOF‐2 ) and nanoscroll ( NMOF‐3 ) morphology, respectively, with surface projected TEG chains. The pre‐formed NMOFs also unveiled reversible solvent responsive transformation of different morphologies. The flexible NMOF showed cyan emission and no cytotoxicity, allowing live cell imaging. Cisplatin (14.4 wt %) and doxorubicin (4.1 wt %) were encapsulated in NMOF‐1 by non‐covalent interactions and, in vitro and in vivo drug release was studied. The drug loaded NMOFs exhibited micromolar cytotoxicity.  相似文献   
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