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111.
Metal oxides are highly reactive towards the compounds of sulphur, particularly thioles. A comparative study was made of the desulphurization potential of various metal oxides such as MnO2, PbO2, ArO3, Al2O3, MgO2, ZnO2 and silica on reaction with Jhal Magsi crude oil and its distillate fractions, i.e., kerosene and diesel oil. The effect of time was also studied and the desulphurization was performed for time durations of one hour, three hours and six hours. The analysis of the residual fractions indicated that significant sulphur depletion occurred with lead oxide and manganese dioxide in the one‐hour and three‐hour reaction times in all three samples. Lead oxide (PbO2) brought about a maximum desulphurization of 60.28% in the case of crude oil, 54.54% in the case of diesel oil and 52.57% in the case of kerosene oil in a 01 h reaction time. Similarly, manganese oxide (MnO2) caused a maximum desulphurization of 58.55% in the case of crude oil, 49.38% in the case of diesel oil and 53.30% in case of kerosene oil in a 3 h reaction time. The rest of the metal oxides also exhibited good sulphur removal activity, but their performance is not as noteworthy as in the cases of PbO2 and MnO2. 相似文献
112.
Abdul Sattar Chang Nusrat Naeem Memon Sidra Amin Fouzia Chang Umair Aftab Muhammad Ishaq Abro Ali dadChandio Aqeel Ahmed Shah Mazhar Hussain Ibupoto Muhammad Akram Ansari Zafar Hussain Ibupoto 《Electroanalysis》2019,31(7):1296-1303
In this study, we have investigated the effect of counter anions on the morphology of cobalt oxide nanostructures. The nanostructures of cobalt oxide are prepared by a low temperature aqueous chemical growth method. The morphology of cobalt oxide nanostructure material was investigated by scanning electron microscopy and the crystalline structure was studied by powder X‐ray diffraction technique. The cobalt oxide nanostructures exhibit the nanowire, lump, bundle of the nanowire and flower‐like morphologies. The XRD study has revealed a cubic phase of cobalt oxide nanostructures. The electro‐catalytic properties of cobalt oxide nanostructures were explored through cyclic voltammetry and amperometric techniques by sensing of lactic acid in the alkaline media. The cobalt oxide nanostructures prepared from cobalt nitrate have shown a well‐resolved redox peak. The proposed mechanism for the non‐enzymatic lactic acid sensor is elucidated by considering the morphology and cyclic voltammetry response. The limit of detection for the sensor was found to be 0.006 mM and it exhibits a linear range from 0.05–3 mM of lactic acid as shown by cyclic voltammetry. The amperometric response has shown the excellent current‐concentration response and the linear range of sensor was found to be 0.1 mM to 5.5 mM. The lactic acid sensor is stable, selective and can be used for practical applications. This study provides an excellent alternative analytical tool for the determination of lactic acid. 相似文献
113.
Iqbal MP Mahmood S Mehboobali N Ishaq M Fatima T Parveen S Frossard P 《Experimental & molecular medicine》2004,36(2):110-115
The angiotensin converting enzyme (ACE) is a strong candidate gene for myocardial infarction (MI). Insertion-deletion dimorphism in intron 16 of this gene has been inconclusively found to be associated with it. Several new polymorphisms in the ACE gene have been identified and among these, a dimorphism in exon 17, ACE G2350A, has a significant effect on plasma ACE concentrations. To assess the value of genotyping the ACE G2350A dimorphism in a genetically homogeneous population, we carried out a case-control study of dimorphism G2350A for a putative association with MI among Pakistani nationals. We investigated a sample population of 370 Pakistanis, comprising 163 controls, and 207 patients with clinical diagnosis of acute MI (AMI). ACE G2350A alleles were visualized by assays based on polymerase chain reaction and restriction endonuclease analysis. Frequencies of G alleles were 0.68 among controls and 0.72 among AMI patients. The ACE G2350A dimorphism showed no significant association with MI (chi2 = 0.90, 2 df, P = 0.64), plasma levels of homocysteine (P = 0.52) or with serum levels of folate (P = 0.299). The results indicate that ACE G2350A polymorphism is not associated with risk of myocardial infarction in the Pakistani population investigated here. 相似文献
114.
Preparation of monosubstituted thiourea complexes of molybdenum carbonyl [Mo(CO)5L] both by thermal and UV irradiation methods have been described. The ligands (L) used were N,N′-dimethylthiourea (DMTU), N,N′-diphenylthiourea (DPTU), tetramethylthiourea (TMTU) and tetraethylthiourea (TETU). The complexes [Mo(CO)5(L)] were characterised by NMR, IR, UV-visible and elemental analyses. 相似文献
115.
116.
Sengul Uysal Aleksandra Cvetanović Gokhan Zengin Saša Đurović Zoran Zeković Abdurrahman Aktumsek 《Analytical letters》2018,51(10):1505-1519
In the last few years, bioactive components or their extraction techniques are gaining special interest in scientific areas. In this framework, orange leaves were used for preparation of extracts with high content of biologically active compounds. To optimize the extraction process, three levels and three variables of Box–Behnken design with response surface methodology were applied. Investigated responses were the total phenolic content (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, cupric ion reducing antioxidant capacity (CUPRAC), and ferric reducing antioxidant power (FRAP). Independent variables were methanol concentration (10–90%), temperature (20–60°C), and extraction time (60–180?min). Experimentally obtained results were fit into a second-order polynomial model with multiple regression. Analysis of variance was used to estimate model fitness and determine optimal conditions for processing. Estimated optimal conditions were 90% methanolic solution, 60°C and 180?min using these parameters; the predicted values of investigated responses were 43.19?mg GAE/g (GAE: gallic acid equivalents), 43.04?mg TE/g (TE: trolox equivalents), 139.34 and 93.76?mg TE/g for TPC, DPPH, CUPRAC, and FRAP, respectively. The obtained optimal conditions could be considered as an alternative strategy for developing novel functional products. 相似文献
117.
ükriye Nihan Karuk Elmas Ibrahim Berk Gunay Abdurrahman Karagoz Aykut Bostanci Gkhan Sadi Ibrahim Yilmaz 《Electroanalysis》2020,32(4):775-780
The selective and sensitive detection of biothiols; cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) in aqueous solutions is of considerable importance because of their pivotal roles in maintaining the reducing environment in the cells. This study describes a strategy for the determination of biothiols based on the PDI/Met‐Hg2+complex platform. We designed and fabricated methionine modified perylene diimide molecule as a selective sensing probe for Hg2+ ions in aqueous solutions ( PDI/Met‐Hg 2+). The complex between perylene bisimide derivative ( PDI/Met) and Hg2+ was investigated and it demonstrated turn‐on fluorescence response for the detection of the biological thiols. Besides, PDI/Met displayed fluorescence quenching response in the presence of mercury ions and the emission intensity of PDI/Met‐Hg2+ was recovered after transferring biothiols (Cys, Hcy, and GSH). Thus, PDI/Met could be utilized as a fluorescent chemosensor for the sequential recognition of mercury ions and biological thiols. 相似文献
118.
Sadin Özdemir Veysi Okumuş Abdurrahman Dündar Kadir Serdar Çelik Uyan Yüksel 《International journal of environmental analytical chemistry》2013,93(6):533-545
Coriolus versicolor, a wood fungus, was immobilised on Amberlite XAD-4 and used as solid-phase biosorbent for preconcentrations of rare earth elements. La(III), Th(IV), U(IV) and Ce(III) were subjected to solid-phase extraction procedure. We observed that La(III) was selectively preconcentrated, while other ions remained in solution at pH 6.0. 5.0 mL of 1.0 mol L?1 HCl was used to elaute La(III) from column. 250 mg of C. versicolor loaded on 1000 mg of XAD-4 was optimised as solid-phase matrix. Concentrations of ions in solutions were determined by inductively coupled plasma– optical emission spectrometry (ICP-OES). The calibration plot after preconcentration was linear in the range from 1.0 to 50.0 ng mL?1 for La(III). Limit of detection was found as 0.27 ng mL?1 for La(III) by SPE method. Relative standard deviation was found lower than 6.7% for 1.0 ng mL?1 of La(III) solution (n = 10). The sensitivity of ICP-OES was improved by a factor of 46.8. The applicability of the method was validated through the analysis of certified reference samples of tea (NCS ZC-73014) and spinach (NCS ZC-73013). 相似文献
119.
Salma Ishaq 《合成通讯》2013,43(5):547-557
Silyl ethers that are synthesized by coupling a propargylic alcohol with an allylsilyl chloride are shown to undergo sulfide‐promoted Pauson–Khand reactions, affording bicyclic enones. 相似文献