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441.
442.
Surekha Kumari Shudh Kirti Dolma Anmol Upendra Sharma S. G. Eswara Reddy 《Molecules (Basel, Switzerland)》2022,27(3)
Aphis craccivora Koch is a polyphagous and major pest of leguminous crops causing significant damage by reducing the yield. Repeated application of synthetic insecticides for the control of aphids has led to development of resistance. Therefore, the present study aimed to screen the insecticidal activity of root/stem extracts/fractions, and pure molecules from Cissampelos pareira Linnaeus against A. craccivora for identification of lead(s). Among root extract/fractions, the n-hexane fraction was found most effective (LC50 = 1828.19 mg/L) against A. craccivora, followed by parent extract (LC50 = 2211.54 mg/L). Among stem extract/fractions, the n-hexane fraction (LC50 = 1246.92 mg/L) was more effective than the water and n-butanol fractions. Based on GC and GC-MS analysis, among different compounds identified in the n-hexane fraction of root and stem, ethyl palmitate (known to possess insecticidal activity) was present in the highest concentration (24.94 to 52.95%) in both the fractions. Among pure molecules, pareirarineformate was found most effective (LC50 = 1491.93 mg/L) against A. craccivora, followed by cissamine (LC50 = 1556.31 mg/L). Parent extract and fractions of C. pareira possess promising activity against aphid. Further, field bio-efficacy studies are necessary to validate the current findings for the development of botanical formulation. 相似文献
443.
A nonsimilar boundary layer analysis is presented for the problem of mixed convection in power-law type non-Newtonian fluids
along a vertical plate with power-law surface heat flux distribution. The mixed convection regime is divided into two regions,
namely, the forced convection dominated regime and the free convection dominated regime. The two solutions are matched. Numerical
results are presented for the details of the velocity and temperature fields. A discussion is provided for the effect of viscosity
index on the surface heat transfer rate.
Received on 13 October 1998 相似文献
444.
Infrared intensity analysis was done in two ways. In one approach, formulas connecting electrooptical parameters (eop's) and intensities were derived and, using the intensities, the former were obtained. In evaluating the eop's the intensity sum equations were used directly so that the sign ambiguity of is avoided. In the other method, polar tensors were obtained directly from intensities. The two methods have now been connected, and polar tensors have been obtained in terms of electrooptical parameters so that the former were also free from sign ambiguity of . They compare well with those obtained directly from intensities. In similar connecting formulas by other authors [see, for example, P. L. Prasad, J. Chem. Phys., 69, 4403, (1978)], both polar tensors and eop's were affected by the sign ambiguity. 相似文献
445.
Vijay Kumari Suresh K. Sahni Sushma Kher Ramesh N. Kapoor 《Transition Metal Chemistry》1980,5(1):85-87
Summary Uranyl(VI) complexes of malonic acid dihydrazide (MDH2) and phthalic acid dihydrazide (PDH2) and the products of their reactions with four -diketones have been characterised by elemental analysis and by electrical conductance, and spectral (i.r. and electronic) measurements. The MDH2 and PDH2 complexes UO2(L)2(H2O)2 are eight coordinate whereas the macrocyclic UO2(L)(H2O)2 complexes are six coordinate. In each complex MDH2 and PDH2 act as bidentate liglands having the coordination sites at secondary amide-nitrogen atoms. 相似文献
446.
The dissociation constants for N-(l-naphthyl)ethylenediamine (NEN) and the formation constants for binary (ML) and ternary
metal complexes (MLA), where M = Cu(II), L = alanine, phenylalanine, tryptophan, lysine, arginine, serine, threonine, aspartic
acid or histidine and A = NEN or ethylenediamine (EN) have been determined by pH titrations and are reported at 35°C (gm = 0.2 M KNO3). The relative stability of the ternary complexes are discussed in terms of statistical effects and the nature of ligands
in the coordination sphere of the metal ion. 相似文献
447.
Sunita Kumari 《Liquid crystals》2013,40(4):522-529
Employing a phenomenological mean field theory, we analyse the effect of high pressure on the B2I phase transition properties of a bent-core liquid crystal. The basic idea of the work is to explain the phase transition behaviour of system by assuming that certain Landau coefficients associated with the order parameters coupling terms of the free-energy density expansion are pressure dependent. We observe excellent agreement between the theoretical and experimental results of mesogen PHDBB and that the B2I transition remains first order even at the elevated pressures. 相似文献
448.
General equations governing the stability of stratified fluid in a stratified porous medium in the presence of suspended particles and variable horizontal magnetic field, separately, have been derived. Assuming stratifications in density, viscosity, suspended particles number density, medium porosity, medium permeability and a magnetic field of exponential form the dispersion relations have been obtained. Systems have been found to be stable for stable stratifications and unstable for unstable stratifications. A system which was unstable in the absence of magnetic field can be completely stabilized by a magnetic field for a certain wave-number range. The behaviour of growth rates with respect to fluid viscosity, medium permeability, suspended particles number density and magnetic field has been examined analytically. 相似文献
449.
Mixed-ligand complexes of Pt(II) and Pt(IV) with 2,6-diaminopurine and 6-thioguanine were synthesized and characterised. The complexes were prepared in acidic and basic media. The binding of the ligands to the metal ion varies according to the pH of the medium. Thus, in the complexes of 6-thioguanine, the ligand acts as a monodentate ligand coordinating through the neutral C6-SH group in the acidic medium and in the basic medium as a bidentate ligand binding to the metal ion through C6S? and N7, forming a five-membered chelate ring. In an acidic medium 2,6-diaminopurine forms mononuclear complexes with Pt(II) and Pt(IV) binding through N7. In a basic medium binuclear hydroxobridged complexes are formed with Pt(IV) and the ligand is monodentate, coordinating through N7. 相似文献
450.
Navjeet Kaur Neha Ahlawat Yamini Verma Pooja Grewal Pranshu Bhardwaj Nirmala Kumari Jangid 《合成通讯》2020,50(8):1075-1132
AbstractOne of the highly emerging and important aspect of organic chemistry is the metal-catalyzed synthesis of the heterocycles. The methodologies used earlier for its synthesis were less approachable to the organic chemist because of their high cost, highly specified instrumentation and inconvenient methods. For both the stereoselective and regioselective synthesis of six-membered nitrogen-containing heterocycles, cyclic reactions that are Cu-catalyzed have known to be very efficient. The presented review covers the varied applications of Cu as a catalyst and its importance in the formation of six-membered nitrogen-containing heterocycles. The fascinating research that has been done in this area is also enclosed in this review. 相似文献