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991.
Ann Ling Tan Li Jian Khoo Siti Salwa Alias Ahmad Azmin Mohamad 《Journal of Sol-Gel Science and Technology》2012,64(1):184-192
This work presents a photo electrochemical cell based on zinc oxide (ZnO) nanoparticles and poly(acrylic) acid (PAA) doped with sodium iodide (NaI) and iodine (I2) polymer gel electrolyte. The ZnO powders were synthesized by sol–gel storage and sol–gel centrifugation. The ZnO powder synthesized via sol–gel centrifugation showed the optimal structural properties, with largest crystallite sizes of 58 nm, average particles size between 20 and 80 nm and indirect band gap energy of 3.20 eV. The highest conductivity [(8.0 ± 0.1) × 10?2 S cm?1] was obtained for PAA + 0.8 M NaI + 0.02 M I2. This sample achieved the lowest activation energy (0.029 eV) and electrochemical stability at 1.6 V. The ZnO powder synthesized via sol–gel centrifugation and PAA + 0.8 M NaI + 0.02 M I2 was fabricated as a Cu–ZnO/PAA + 0.8 M NaI + 0.02 M I2/C-ITO photo electrochemical cell. 相似文献
992.
The performance of matrix assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF) of bacterial proteins strongly depends on sample preparation. It is found that the mass spectral profiles obtained from direct MALDI-TOF MS of the protein extracts are much weaker for individual bacterial cells than compared to those prepared by the Tris-EDTA buffer approach (TEBA). Characteristic mass spectral peaks were observed in the mass range from 3,000 to 15,000?Da. The mass peaks reported earlier and claimed to serve as species-specific biomarkers are consistently found here as well. Mass peaks at m/z of 3636, 5466, 5750, 6315, 6547, 7274, 9192, and 9742 are found for Escherichia coli studied and assigned as specific biomarkers. Similarly, specific mass peaks have been identified at m/z 5443, 7270, 7724, and 9888 for Bacillus subtilis, and at 3603, 5496, 6800, 8858 and 9531 for Serratia marcescens. The detection limits for the three target bacteria range from 2.4?×?105 to 3.3?×?105?cfu·mL-1. We conclude that the TE buffer approach can produce reliable data for rapid classification, high-resolution and highly sensitive detection of bacteria. Fig
The Tris-EDTA buffer approach is a sample preparation technique before MALDI-TOF MS analysis. In this study, the bacterial cells were treated with Tris-EDTA buffer for high resolution MALDI-TOF mass spectrometry. It is important to note that mass spectral profiles obtained from direct MALDI-TOF MS of protein extracts are much weaker for individual bacterial cells than compared to those prepared by the Tris-EDTA buffer approach. The current approach is very simple and rapid for high sensitive detection of bacteria. 相似文献
993.
Muhammad Akhyar Farrukh Chin-Kiat Thong Rohana Adnan Mohd Amirrul Kamarulzaman 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(13):2041-2048
In this work, we report the formation of leaf-like ZnO nanoflakes by anodization of zinc foil in a mixture of ammonium sulfate and sodium hydroxide electrolytes under various applied voltage and concentration of sodium hydroxide. The morphology and structure of ZnO nanoflakes were investigated by field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis. In addition, the photocatalytic activity of the prepared nanoflakes zinc oxide was evaluated in the photodegradation of organic dye methylene blue (MB) solution under UV irradiation. It was found that zinc oxide prepared under high concentration of sodium hydroxide and high voltage showed better performance in the photodegradation of methylene blue. 相似文献
994.
A new protocol has been developed for the efficient synthesis of structurally diverse 1H-pyrazolo[1,2-b]phthalazine-1,2-dicarboxylates and 1H-pyrazolo[1,2-a]pyridazine-1,2-dicarboxylates via a four-component reaction of hydrazine hydrate, dialkyl acetylenedicarboxylates, isocyanides and various cyclic anhydrides such as succinic anhydride, maleic anhydride and phthalic anhydride in ethanol/acetone (1:1) at room temperature in good to moderate yields. 相似文献
995.
J.S. Yadav Sandip Sengupta Nagendra Nath Yadav D. Narasimha Chary Ahmad Alkhazim Al Ghamdi 《Tetrahedron letters》2012,53(44):5952-5954
(−)-Lardolure and (2R,4R,6R,8R)-2,4,6,8-tetramethylundecanoic acid have been synthesized via lipase catalyzed desymmetrization strategy to create two methyl chiral centers. Other key steps involved in the synthesis are Wittig reaction, Evan’s asymmetric alkylation, Grignard reaction, Pd-catalyzed isomerization of primary allylic alcohol to corresponding saturated aldehyde, and PhNO/proline catalyzed MacMillan α-hydroxylation. 相似文献
996.
A Ph3P‐catalyzed cyclization of α‐halogeno ketones 2 with dialkyl acetylenedicarboxylates (=dialkyl but‐2‐ynedioates) 3 produced halogenated α,β‐unsaturated γ‐butyrolactone derivatives 4 in good yields (Scheme 1, Table). The presence of electron‐withdrawing groups such as halogen atoms at the α‐position of the ketones was necessary in this reaction. Cyclization of α‐chloro ketones resulted in higher yields than that of the corresponding α‐bromo ketones. Dihalogeno ketones similarly afforded the expected γ‐butyrolactone derivatives in high yields. 相似文献
997.
A highly sensitive ultra high pressure liquid chromatography (UHPLC‐MSMS) method for estimation of ropinirole in rat brain homogenate and plasma has been validated. The method was successfully used for the degradation kinetics in different stress condition and regulated temperature. The chromatographic separation was achieved using isocratic mobile phase, consisting of acetonitrile–2mM ammoniumacetate (28:72 v/v; 0.25 mL min?1). The mass spectrometer was operated in synapt mass spectrometry mode via positive electrospray ionization using the transitions m/z 260 → m/z 261 for ropinirole, and m/z 324.39 → m/z 262.161 as a parent ion of escitalopram (IS). The assay for ropinirole was linear over the range of 0.5–100 ng mL?1 (r2; 0.999). The intra‐ and inter day precisions were less than 11.2% in terms of relative standard deviation (R.S.D.), and the accuracy was within ±6.4% in terms of relative error (RE). The mean extraction‐efficiency of QC samples (MQC, 8 ng/mL) was ≥80%. The lower limit of quantification (LLOQ) was 0.049 ng/mL where as lower limit of detection (LLOD) was 0.016 ng/mL. All the peaks of degradation were well resolved. The degradation kinetics of ropinirole, showed highest stability (t1/2 256.66/h; t0.9, 39.11/h) in acidic medium, lower stability in alkaline environment (t1/2, 103.43/h; t0.9, 15.76/h) and highly susceptible in oxidative environment (t1/2, 21.58/h; t0.9, 3.28/h). The applicability of this assay was demonstrated and successfully applied for pharmacokinetic profiling of ropinirole in Wister rat brain homogenate after intranasal administration. 相似文献
998.
Using Monte Carlo simulation techniques, we calculate the phase diagram for a square-shoulder square-well potential in two dimensions that has been previously shown to exhibit liquid anomalies consistent with a metastable liquid-liquid critical point. We consider the liquid, gas, and five crystal phases, and find that all the melting lines are first order, despite a small range of metastability. One melting line exhibits a temperature maximum, as well as a pressure maximum that implies inverse melting over a small range in pressure. 相似文献
999.
Khan Z Al-Thabaiti SA Obaid AY Khan ZA Al-Youbi AA 《Journal of colloid and interface science》2012,367(1):101-108
We report a simple chemical reduction method for the synthesis of different colored silver nanoparticles, AgNP, using tyrosine as a reducing agent. Effects of cetyltrimethylammonium bromide, CTAB, and tyrosine concentrations are analyzed by UV-visible measurements and scanning electron microscopy (SEM) to evaluate the mode of AgNP aggregation. The position and shape of the surface resonance plasmon absorption bands strongly depend on the reaction conditions, i.e., [CTAB], [tyrosine], and reaction time. Sub-, post-, and dilution-micellar effects are accountable for the fast and slow nucleation and growth processes. Spectrophotometric measurement also shows that the average size and the polydispersity of AgNP increase with [CTAB] in the solution. CTAB acted as a shape-directing agent. 相似文献
1000.
Shaeel Ahmed Al-Thabaiti Abdullah Yousif Obaid Ziya Ahmad Khan Tanweer Ahmad Arniza Ghazali Kabir-ud-Din 《Colloid Journal》2012,74(1):125-131
The energetics of clouding in anionic surfactant (SDBS) and tetrabutylammonium bromide system in the presence of additives,
such as ureas, amino acids and sugars is reported. The change of standard Gibbs energy of solubilization (ΔG
s
o) for all of the additives was found to be negative. The values of change of standard enthalpy (ΔH
s
o) and that of standard entropy (TΔS
s
o) values were found to depend on the type and chemistry of the additive. The results were explained on the basis including
chemistry of additives, their effect on water structure, and solubilization of additives either in the micellar or in aqueous
phases. 相似文献