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81.
Javid Hussain Hidayatullah Khan Liaqat Ali Abdul Latif Khan Najeeb Ur Rehman Sajid Jahangir Ahmed Al‐Harrasi 《Helvetica chimica acta》2015,98(5):719-723
The phytochemical investigations on Cleome droserifolia resulted in the isolation and characterization of a new indole alkaloid, 5‐hydroxy‐2‐methoxy‐1‐methyl‐1H‐indole‐3‐carbaldehyde ( 1 ). The structure elucidation was carried out on the basis of 1D‐ and 2D‐NMR techniques. In addition to 1 , two known aromatic derivatives, veratrol ( 2 ) and 2‐methoxy‐4‐methylacetophenone ( 3 ), were also obtained. All these compounds were purified by repeated column chromatography of the CH2Cl2 fraction obtained from MeOH extract of Cleome droserifolia. The structure of the new compound 1 was finally confirmed by the combined 1D (1H‐ and 13C‐) and 2D (H? C correlations; HMBC and HSQC) NMR and IR spectroscopy, mass spectrometry (MS), and UV absorption spectroscopy techniques. The comparison of the physical and spectroscopic data with those in the literature provided evidence for the structure confirmation of known compounds. All the purified compounds were subjected to urease and α‐glucosidase enzymes inhibition. The results showed that compound 1 was more potent with an IC50 value 11.97±2.067 μg/ml towards urease inhibition, while the activity of α‐glucosidase enzyme was marginal. 相似文献
82.
Synthesis characterization and biological study of diorganotin(IV) complexes of monomethyl phthalate
Rehman W Baloch MK Badshah A Ali S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(3-4):689-694
The synthesis and characterization of new coordination compounds of some organotin(IV) chlorides with monomethyl phthalate is reported; the ligand molecules appear to be bound to the tin atom through carbonyl oxygen atoms. Their structures have been characterized by elemental analyses, molar conductance, and bonding in these complexes is discussed in terms of their IR, (1)H, (13)C, (119)Sn NMR and (119 m)Sn M?ssbauer spectral studies. The spectroscopic results obtained are in full agreement with the proposed 2:1 stoichiometry. The complexes soluble in DMSO have been screened against a wide spectrum of bacteria and the results obtained are quite promising. The LD(50) values have also been determined in the albino rats. Some of the complexes also exhibit high anti-inflammatory activity. 相似文献
83.
Saba Noor Muhammad Waseem Umer Rashid Muhammad Anis-ur-Rehman Wajid Rehman Khalid Mahmood 《中国化学快报》2014,25(5):819-822
We have prepared silica,SiO2coated NiO and NiO coated SiO2by sol-gel method.The physicochemical properties of the desired materials were investigated by surface charge properties,scanning electron microscopy(SEM),energy dispersive X-ray(EDX) spectroscopy,surface area measurements and X-ray diffraction(XRD) analyses.The point of zero charge(PZC) of the solid was determined by the salt addition method.In coated materials,two PZC values were noted representing the surface charge of their counterparts.The SEM image of SiO2coated NiO displays a uniform coating of silica on the surface of NiO whereas in case of NiO coated SiO2,a honeycomb like appearance was observed with highly porous structures.In the diffractograms of NiO,the characteristic peaks were suppressed in NiO coated silica however,no diffraction peak could be seen in SiO2coated NiO.Batch adsorption technique was applied for the removal of Pb2+ions from aqueous solution.The sorption trend for Pb2+ions was observed in the order of NiO coated SiO2〉 SiO2coated NiO 〉 NiO 〉 SiO2.This trend confirms that the coated materials have more sorption capacities than their parent counterparts. 相似文献
84.
85.
Rehman Samiya Keefover-Ring Ken Haq Ihsan ul Dilshad Erum Khan Mohammad Imran Akhtar Nosheen Mirza Bushra 《Applied biochemistry and biotechnology》2019,188(3):893-895
Applied Biochemistry and Biotechnology - The original version of this article unfortunately contained a mistake in the image of Figure 1 and in Table 4. The corrected version of the figure... 相似文献
86.
Adil Amin Aijaz Ahmad Dar Mohsin Ahmad Bhat Musarat Jan Nuzhat Rehman Mohammad Amin Mir 《Journal of Dispersion Science and Technology》2013,34(3):406-414
The present study deals with the interaction of sodium alkanoates viz. sodium acetate, sodium propionate, sodium butanoate, sodium hexanoate and sodium benzoate on the micellization of dodecylbenzyldimethylammonium chloride using conductometeric and flourscence quenching experiments carried out at 25°C. The analysis has been made through study of variation of critical micelle concentration (cmc), degree of counterion binding (β), aggregation number (N), and micropolarity with the concentration of these hydrophobic salts. The differentiation between the effects of hydrophobic and inorganic salts was made by comparing the above results with the influence of NaCl on cmc, β, and N. 相似文献
87.
Mohammad Shakirullah Imtiaz Ahmad Mohammad Saeed Mohammad Arsala Khan Habib‐ur‐Rehman Mohammad Ishaq Amjad Ali Shah 《中国化学会会志》2006,53(2):335-342
The present paper demonstrates the review of some acid processes as well as development of some new solvent processes for reclamation of used lubricating oils. The conventional processes are found to be of low yield (? 50%), laborious, time consuming and environmentally hazardous, because of residual acidic sludge. Based on the findings, a new modified Aluminium sulphate‐sodium silicate‐acid‐base method employing a small quantity of acid and giving a high yield (? 60%) is proposed. Further, to avoid use of acid, new regeneration processes based on solvent extraction were investigated. They are termed CCl4‐alcohol method, Dodecane‐alcohol method and Toluene‐alcohol method. These processes are not only cost effective in terms of complete solvent recovery, but are rapid, less time consuming, more environmentally friendly and gave a high yield (70–75%). The virgin lubricants (Castrol GTX and Rimula‐C) as well as oils recovered by different methods were also characterized physicochemically to determine kinematic viscosity, density, refractive index, carbon distribution, wear scar diameter, % Conradson carbon residue, % ash, % chloride, pour point, etc. Results obtained show that many of the physico‐chemical properties of the recovered oils are in good agreement with those of virgin oils. The n.d.M analysis was also performed which shows that virgin oils have 73 ± 3% paraffinic carbon, 26 ± 3% naphthenic carbon and about 1% aromatic carbon. The recovered oils also showed nearly the same chemical composition. The UV‐Visible spectra of the recovered oils are all similar to those of virgin lubricants. The results suggest that the oils recovered by solvent treatments, particularly Dodecan‐alcohol and Toluene‐alcohol methods, may serve for lubrication purposes and can be rendered as excellent as virgin lubricants with the addition of certain additives. The proposed methods may be considered as alternative cost effective green techniques for acid reclamation processes and being the motivation of the present investigation. 相似文献
88.
Lieberzeit PA Rehman A Najafi B Dickert FL 《Analytical and bioanalytical chemistry》2008,391(8):2897-2903
Continuous surveillance of composting processes would enable a feedback loop to be obtained for both analysis and process
control. For this purpose, we designed e-noses based on a six-electrode quartz-crystal microbalance (QCM) array coated with
affinity materials and molecularly imprinted polymers (MIP). They enable quantitative monitoring of volatile organic compounds
(VOCs) emitted directly in a compost bin and are highly suitable tools for achieving on-line characterization of the degradation
processes occurring. During grass and pine composting (duration 14 days and 40 days, respectively), we observed concentrations
of up to 250 ppm of esters, 700 ppm of alcohols, 250 ppm of terpenes, and 90% relative humidity directly on-line with such
a system and could validate the data off-line by GC-MS. The sensor also gave direct insight into the differences between the
two composting batch types. Besides duration, during grass composting larger amounts of alcohols are emitted whereas relative
amount of terpenes is twice as high for pine composting. Detailed correlation of the sensor and the GC-MS data allows approximate
estimation of the sensitivity of the sensor materials towards analyte classes such as, e.g., aliphatic alcohols or terpenes.
Figure Mass sensitive sensor arrays coated with different molecularly imprinted and affinity materials are a highly suitable tool
for quantitatively monitoring solvent patterns during composting procedures on-line in a composter headspace.
Dedicated to Professor Udo Brinker on the occasion of his 65th birthday. 相似文献
89.
Five novel triorganotin(Ⅳ) complexes have been synthesized by refluxing trimethyl, triethyl, tributyl, triphenyl and tribenzyltin chloride with Cephlaxine.These compounds were characterized by spectroscopic (IR,1H, 13C, 119Sn NMR) techniques and elemental analysis.The results obtained through these techniques are in full agreement with the proposed 1:1 stoichiometry.The synthesized compounds were than tested against various microorganisms and fungi.The results of new products obtained showed that the triphenyltin(IV) complex displayed promising activity against all types of bacteria and fungi used while all other compounds showed significant antibacterial and antifungal activity. 相似文献
90.
S. M. Hasany M. A. Rauf H. Rehman 《Journal of Radioanalytical and Nuclear Chemistry》1991,153(1):5-14
Gamma irradiation studies of morin (10–5M) in ethanol and dimethyl sulphoxide (DMSO) in the dose range of 149–895 Gy and of 4.5–45 Gy were carried out, respectively, in aerated and anoxic conditions purged with nitrogen and nitrous oxide. The decoloration yield of morin was studied as a function of dose. The relative radiation sensitivity was estimated under similar conditions. The effect of the concentration (10–5–10–4M) of iodine, succinic acid and acryl amide on radiolysis of morin was investigated at constant dose in both solvents and results were interpreted in terms of scavenging reactions. 相似文献