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排序方式: 共有150条查询结果,搜索用时 156 毫秒
61.
Ashraf A. Wani Alamgir A. Dar Ishrat Jan Malik Mukhtar Khurshid A. Sofi G. I. Hassan Javid A. Sofi 《Biomedical chromatography : BMC》2022,36(4):e5335
Herein we report a novel, accurate and cost-effective gas chromatography method for the determination of average deposits of profenofos on green pea and cucumber following good agricultural practices. Additionally the risk assessment, dissipation and waiting period for profenofos were determined. The average initial deposits (2 h after spraying) of profenofos in/on green pea and cucumber were 3.41 and 3.62 mg kg−1 respectively following two applications at a 10 day interval of profenofos 50EC formulation. Profenofos residues on both of the substrates were below the detection limit of 0.05 mg kg−1 after 20 days at the recommended dosage. For risk assessment studies, the 20th day will be safe for consumers for consumption of green peas. The gas chromatography method was validated according to the SANTE guidelines using the various analytical parameters: linearity, accuracy, detection and quantification limits. The developed method is simple, selective and repeatable and can be extended for profenofos-based standardization of pesticide formulations for green pea/cucumber and their use as pesticides. 相似文献
62.
63.
Jungck's Common Fixed Point Theorem and E.A Property 总被引:1,自引:0,他引:1
M. IMDAD Javid ALI 《数学学报(英文版)》2008,24(1):87-94
We prove that (E.A) property buys the required containment of range of one mapping into the range of other in common fixed point considerations up to a pair of mappings. While proving our results, we utilize the idea of implicit functions due to Popa, keeping in view their unifying power. 相似文献
64.
65.
Sangita Roy Nadeem Javid Pim W. J. M. Frederix Dimitrios A. Lamprou Andrew J. Urquhart Neil T. Hunt Prof. Peter J. Halling Prof. Rein V. Ulijn 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(37):11723-11731
We report on a pronounced specific‐ion effect on the intermolecular and chiral organization, supramolecular structure formation, and resulting materials properties for a series of low molecular weight peptide‐based hydrogelators, observed in the presence of simple inorganic salts. This effect was demonstrated using aromatic short peptide amphiphiles, based on fluorenylmethoxycarbonyl (Fmoc). Gel‐phase materials were formed due to molecular self‐assembly, driven by a combination of hydrogen bonding and π‐stacking interactions. Pronounced morphological changes were observed by atomic force microscopy (AFM) for Fmoc‐YL peptide, ranging from dense fibrous networks to spherical aggregates, depending on the type of anions present. The gels formed had variable mechanical properties, with G′ values between 0.8 kPa and 2.4 kPa as determined by rheometry. Spectroscopic analysis provided insights into the differential mode of self‐assembly, which was found to be dictated by the hydrophobic interactions of the fluorenyl component, with comparable H‐bonding patterns observed in each case. The efficiency of the anions in promoting the hydrophobic interactions and thereby self‐assembly was found to be consistent with the Hofmeister anion sequence. Similar effects were observed with other hydrophobic peptides, Fmoc‐VL and Fmoc‐LL. The effect was found to be less pronounced for a less hydrophobic peptide, Fmoc‐AA. To get more insights into the molecular mechanism, the effect of anions on sol–gel equilibrium was investigated, which indicates the observed changes result from the specific‐ion effects on gels structure, rather than on the sol–gel equilibrium. Thus, we demonstrate that, by simply changing the ionic environment, structurally diverse materials can be accessed providing an important design consideration in nanofabrication via molecular self‐assembly. 相似文献
66.
Javid Hussain Meamoona Munir Zahid Hassan Naseem Bano Saima Arshad Viqar Uddin Ahmad 《Helvetica chimica acta》2010,93(2):350-353
One new ceramide (=long‐chain base linked to a fatty acid via an amide bond), tanacetamide D ( 1 ), was isolated from Tanacetum artemisioides. Besides this, the two known constituents 5‐demethylnobiletin ( 2 ) and 5‐hydroxy‐3,6,7,8,3′,4′‐hexamethoxyflavone ( 3 ) were isolated for the first time from this species. The structure elucidation of the isolated compounds were based primarily on 2D‐NMR techniques including correlation spectroscopy (COSY), heteronuclear multiple‐quantum coherence (HMQC), heteronuclear multiple‐bond correlation (HMBC), and nuclear Overhauser effect spectroscopy (NOESY) experiments. 相似文献
67.
Biocatalytic Self‐Assembly of Supramolecular Charge‐Transfer Nanostructures Based on n‐Type Semiconductor‐Appended Peptides 下载免费PDF全文
Dr. Siva Krishna Mohan Nalluri Cristina Berdugo Dr. Nadeem Javid Dr. Pim W. J. M. Frederix Prof. Rein V. Ulijn 《Angewandte Chemie (International ed. in English)》2014,53(23):5882-5887
The reversible in situ formation of a self‐assembly building block (naphthalenediimide (NDI)–dipeptide conjugate) by enzymatic condensation of NDI‐functionalized tyrosine ( NDI‐Y ) and phenylalanine‐amide ( F‐NH2 ) to form NDI‐YF‐NH2 is described. This coupled biocatalytic condensation/assembly approach is thermodynamically driven and gives rise to nanostructures with optimized supramolecular interactions as evidenced by substantial aggregation induced emission upon assembly. Furthermore, in the presence of di‐hydroxy/alkoxy naphthalene donors, efficient charge‐transfer complexes are produced. The dynamic formation of NDI‐YF‐NH2 and electronic and H‐bonding interactions are analyzed and characterized by different methods. Microscopy (TEM and AFM) and rheology are used to characterize the formed nanostructures. Dynamic nanostructures, whose formation and function are driven by free‐energy minimization, are inherently self‐healing and provide opportunities for the development of aqueous adaptive nanotechnology. 相似文献
68.
Abstract The work presented in this article consists of synthesis of chiral dithioacetals and oxathioacetals using pure chiral auxiliaries, such as, (+) camphor, (?) menthol, and L‐cysteine. Metalation of these chiral dithioacetals and oxathioacetals, followed by nucleophilic addition to benzaldehyde and removal of chiral auxiliary, furnished scalemic mandelic acid with various enantiomeric purities. 相似文献
69.
Javid H. Zaidi 《合成通讯》2013,43(12):2407-2419
A simple preparation of n-butyl chloromethyl ether is described which can be extended to other alkyl chloromethyl ethers. n-Butoxymethyl ether derived from n-butyl chloromethyl ether and phenol were used to assess the effectiveness of n-butoxymethyl group in ortho-metalation. 相似文献
70.
This work presented a new approach to solve the location management problem by using the location areas approach. A combination
of Genetic Algorithm and Hopfield Neural Network is used to find the optimal configuration of location areas in a mobile network.
Toward this end, the location areas configuration of the network is modeled so that the general condition of all the chromosomes
of each population improves rapidly by the help of a Hopfield Neural Network. The Hopfield Neural Network is included in the
Genetic Algorithm optimization process, to expedite its convergence, since the generic Genetic Algorithm is not fast enough.
Simulation results are very promising and they lead to network configurations that are unexpected.
相似文献