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581.
Molecular Diversity - Machine learning (ML) methods have attracted increasing interest in chemistry as in all fields of science in recent years. This method is of great importance for the design of... 相似文献
582.
The chemistry of two bicyclic endoperoxides, obtained by photooxygenation of 2,3‐benzotropone (=5H‐benzocyclohepten‐5‐one; 5 ) and of its ethyl carboxylate derivative 15 , was investigated with the aim of synthesizing the respective benzotropolone derivatives. The reaction of the endoperoxide 10 derived from 5 with thiourea gave the desired benzotropolone, i.e., 6‐hydroxy‐5H‐benzocyclohepten‐5‐one ( 11 ), in high yield (Scheme 1). On the other hand, the endoperoxide 16 derived from the ethyl carboxylate derivative 15 underwent an unprecedented transformation yielding mainly the ring‐contracted lactones 28 and 29 besides the expected substituted benzotropolone derivative 27 (Scheme 5). However, the thermolysis reaction of the same endoperoxide 16 resulted in the formation of four rearranged compounds with different skeletons (Scheme 3). The formation mechanism of all products is discussed (Schemes 4 and 6). 相似文献
583.
Abdulqader Alhaider Abdel Galil Abdelgader Abdullah Arif Turjoman Keri Newell Stephen W. Hunsucker Baozhen Shan Bin Ma David S. Gibson Mark W. Duncan 《Journal of mass spectrometry : JMS》2013,48(7):779-794
The milk of the one‐humped camel (Camelus dromedarius) reportedly offers medicinal benefits, perhaps because of its unique bioactive components. Milk proteins were determined by (1) two‐dimensional gel electrophoresis and peptide mass mapping and (2) liquid chromatography–tandem mass spectrometry (LC–MS/MS) following one‐dimensional polyacrylamide gel electrophoresis. Over 200 proteins were identified: some known camel proteins including heavy‐chain immunoglobulins and others exhibiting regions of exact homology with proteins from other species. Indigenous peptides were also identified following isolation and concentration by two strategies: (1) gel‐eluted liquid fraction entrapment electrophoresis and (2) small‐scale electrophoretic separation. Extracts were analyzed by LC–MS/MS and peptides identified by matching strategies, by de novo sequencing and by applying a sequence tag tool requiring similarity to the proposed sequence, but not an exact match. A plethora of protein cleavage products including some novel peptides were characterized. These studies demonstrate that camel milk is a rich source of peptides, some of which may serve as nutraceuticals. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
584.
Siddiqi ZA Arif R Kumar S Khalid M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(5):1193-1197
The homo-bimetallic complexes of stoichiometry Fe2(L)ClO4(ClO4)2 where L are novel unsymmetrical [N10] (L1.2HClO4) and [N12] (L2.2HClO4) macrocyclic ligands, have been prepared. The ligands were obtained from an in situ capping reaction of the reactive substrate, N,N'-bis(N-ethylaniline)hydrazine-1,2-diimine with a mixture of aniline or 1,3-diaminopropane and HCHO in presence of HClO4. The compounds have been characterized by elemental analyses, conductometric, IR, FAB-mass and electronic spectral studies. IR data of complexes suggest coordination from unsymmetrical aza sites as a tridentate (N,N,N) or tetradentate (N,N,N,N) ligand. mu(eff) values of the complexes suggest presence of antiferromagnetically coupled (Fe3+-Fe3+=S5/2-S5/2) spin exchange. M?ssbauer parameters of the complexes support (+/-3/2)-->(+/-1/2) nuclear transition in high-spin configurations of Fe(III) nuclei of the homo-bimetallic complexes with the presence of Kramer's double degeneracy. 相似文献
585.
Raza Mohsan Srivastava Hari Mohan Arif Muhammad Ahmad Khurshid 《The Ramanujan Journal》2021,55(1):53-71
The Ramanujan Journal - In this paper, we study the coefficient estimates for a class of analytic functions defined by using the q-Ruscheweyh derivative operator. In particular, we investigate the... 相似文献
586.
Arif Salimov 《Journal of Geometry》2010,99(1-2):107-145
The aim of this paper is to introduce some operators which are applied to pure tensor fields. In this context Tachibana, Vishnevskii, Yano–Ako operators and their generalizations can be found. 相似文献
587.
We give a characterization of bicomplex-holomorphic anti-Hermitian manifolds by using pure metric connection 相似文献
588.
Muhammad Qaiser Shahbaz Saman Shahbaz Mohammad Mohsin Arif Rafiq 《Applied Mathematics Letters》2010,23(5):567-570
The distributions of two concomitants have been given when a random sample is available from a trivariate distribution. The illustration has been given by using a trivariate Pseudo-Exponential distribution. 相似文献
589.
Abdul Qadir Nausheen Khan Muhammad Arif Musarrat Husain Warsi Shehla Nasar Mir Najib Ullah Mohammad Yusuf 《印度化学会志》2022,99(6):100503
Trigonella foenumgraecum L. (TF) is a medicinal herb, belonging to the family Legumes. It has shown positive results in remedying hypo-cholesterolemic, anti-inflammatory, antibacterial, antioxidant, anti-lipidemia, antilithigenic, hepatoprotective, antiulcer, anticarcinogenic, antifungal and other miscellaneous pharmacological effects of fenugreek. The n-hexane extract of Trigonella foenumgraecum L. Seeds (TF) was analysed by gas chromatography-mass spectroscopy for identification and characterization of its therapeutic claim by traditional system. DPPH method was used to determine the antioxidant activity of Trigonella foenumgraecum L-seeds extract using UV spectrophotometer at a wavelength of 518 nm as it is one of the most sorted methods for antioxidant activity. The major compounds discovered in Trigonella foenumgraecum L. seeds extract are Linoleic acid (48.01%); 9,12-Octadecadienoic acid (Z,Z)-, 2,3-dihydroxypropyl ester (24.65%); 2-[4-Methyl-6-(2,6,6-trimethylcyclohex-1-enyl)hexa-1,3,5-trienyl]cyclohex-1-en-carboxaldehyde(1.88%); Nonane dioic acid, bis (2-ethylhexyl) ester (1.09%); Bis (2-ethylhexyl) ester of azelaic acid (11.97%); Elemicin (0.51%); cis-Linoleic acid methyl ester (0.76%); Linoleic acid chloride(0.57%); Ethyl oleate(0.18%); Isopropyl linoleate (0.38%); Dihydrovallesiachotamine (0.06%); 4-(2,2-Dimethyl-6-methylenecyclohexyl) butanal(0.12%); Citronellyl myristate (0.09%); Rhaphidecursinol B(0.25%); 5-Methoxygalbelgin (0.07%); Vitamin E (0.31%); 1,1,1,5,5,5-hexafluoro-4-{[3-(trifluoromethyl) phenyl]imino}-2-pentanone (0.76%); γ-Sitosterol (0.66%); 1-(1,5-Dimethylhexyl)-3a,12a-dimethyltetradecahydro-1H-cyclopenta[a]cyclopropa[e]phenanthren-7-ol (0.16%) and (9Z)-9-Octadecenyl (9Z)-9-hexadecenoate (1.57%). The results showed potential antioxidant activity of n-hexane extract of Trigonella foenumgraecum L. seeds by showing significant reduction in free radical against DPPH. The hexane extract of Trigonella foenumgraecum L. seeds comprises various non-water-soluble (nonpolar) constituents. These compounds were established qualitatively via GC-MS evaluation. The free radical scavenging activity of the plant extract was established owning to the presence of compounds such as terpenes, vitamin E, and unsaturated fatty acids. 相似文献
590.
The apparent reduction of reduced nicotinamide adenine dinucleotide (NADH) in acidic media at a static mercury drop electrode was investigated. A simple, quick pretreatment procedure was developed to convert the NADH to its acid-hydrated form. This adsorbs on the mercury surface during a film deposition time and the film is then reduced. The adsorption is diffusion-controlled and hence the peak currents for square-wave and linear-scan voltammetry are proportional to Ct1/2pAf and Ct1/2pAv, respectively, where tp is the effective film deposition time, C the concentration of NADH, A the electrode area, f the square-wave frequency, and ν the linear scan rate. Several electrochemical techniques were compared for the determination of NADH; the method of choice is square-wave voltammetry, although staircase or linear scan voltammetry can also be used. The detection limit is less than 7 nM, and the range of linear response covers 2–3 orders of magnitude of NADH concentration. 相似文献