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281.
282.
The reaction kinetics of the Autocatalytic Oxidation of L-asparagine by permanganate ions has been investigated in moderately strong acid medium using the spectrophotometric technique. In all cases studied, an autocatalytic effect due to Mn2+ ions formed as a reaction product was observed. Both catalytic and noncatalytic processes were determined to be first order with respect to the permanganate ions while a first and a fractional order with respect to the amino acid for noncatalytic and catalytic reactions were obtained, respectively. The overall rate equation for this process may be written asd[MO4
–]/dt= k´1[MnO4
–]+k´2[MnO4
–][Mn+2],where k´1 and k´2 are rate pseudoconstants for noncatalytic and catalytic reactions, respectively. The influence of some factors such as temperature and reactant concentration on the rate constants has been studied, and the activation parameters have been calculated. Reaction mechanisms satisfying observations for both catalytic and noncatalytic routes have been presented. 相似文献
283.
A simple kinetic spectrophotometric method was developed for the determination of josamycin in its dosage forms. The method is based on oxidation of the drug with alkaline potassium permanganate at room temperature for a fixed time of 20 min and measuring the produced green color at 611 nm. The absorbance-concentration plot is rectilinear over the range of 2-10 microg/mL (2.4 x 10(6)-1.2 x 10(-5)M) with minimum detectability of 1.0 microg/mL (1.2 x 10(-6)M). The determination of josamycin by fixed concentration and the rate-constant methods is also feasible with the calibration equations obtained, but the fixed-time method proved to be more applicable. The procedure was applied successfully to commercial tablets, and statistical analysis showed that the results compared favorably with those obtained by reference methods. The effect of sensitizers and surfactants on the performance of the proposed method was also studied. A proposal of the reaction pathway was presented. 相似文献
284.
The aldol condensation reaction of cyclic ketones with aromatic aldehydes in ethanol under reflux conditions using ZrCl4 as a catalyst to afford the corresponding α,α′‐bis(substituted benzylidene and cinnamylidene)cycloalkanones in excellent yields has been described. No self‐condensation product was produced. 相似文献
285.
Shirin Bahrami Amarjeet Bassi Ernest Yanful 《Journal of Sol-Gel Science and Technology》2007,42(2):119-126
The application of silica sol–gel particles containing crude metallothionein (MT) was investigated for cadmium removal from
water. The metallothionein was first extracted from the yeast Scchizosaccharomyces pombe, and entrapped in the sol–gel matrices. Then sol–gel particles with the different sizes (ranging from 45 to 225 μm) were
made. The effect of different flow rates as well as different particle sizes on adsorption of cadmium was investigated. The
particle size has a greater effect on Cd adsorption than flow rate in the system studied. The breakthrough curves in the column
were modeled using an empirical two parameter fixed-bed adsorption model. The model relates the changes of cadmium concentration
in effluent to the standard deviation (σ) and characteristic of time (t
0). 相似文献
286.
Farid Bahrami Henrik Shahgholian 《Proceedings of the American Mathematical Society》1998,126(3):745-750
For set , and let be a measure with compact support. Suppose, for , there are functions and (bounded) domains , both containing the support of with the property that in (weakly) and in the complement of . If in addition is convex, then and .
287.
Moncer A. Hariga Abdulrahman Al-Ahmari Abdel-Rahman A. Mohamed 《European Journal of Operational Research》2007
In this paper, we propose an optimisation model to determine the product assortment, inventory replenishment, display area and shelf space allocation decisions that jointly maximize the retailer’s profit under shelf space and backroom storage constraints. The variety of products to be displayed in the retail store, their display locations within the store, their ordering quantities, and the allocated shelf space in each display area are considered as decision variables to be determined by the proposed integrated model. In the model formulation, we include the inventory investment costs, which are proportional to the average inventory, and storage and display costs as components of the inventory costs and make a clear distinction between showroom and backroom inventories. We also consider the effect of the display area location on the item demand. The developed model is a mixed integer non-linear program that we solved using LINGO software. Numerical examples are used to illustrate the developed model. 相似文献
288.
Abdulrahman Th. Mohammad Sohif Bin Mat M. Y. Sulaiman K. Sopian Abduljalil A. Al-abidi 《Heat and Mass Transfer》2013,49(11):1587-1593
A computer simulation using MATLAB is investigated to predict the distribution of air stream parameters (humidity ratio and temperature) as well as desiccant parameters (temperature and concentration) inside the parallel plate absorber. The present absorber consists of fourteen parallel plates with a surface area per unit volume ratio of 80 m2/m3. Calcium chloride as a liquid desiccant flows through the top of the plates to the bottom while the air flows through the gap between the plates making it a cross flow configuration. The model results show the effect of desiccant mass flow rate on the performance of the dehumidifier (moisture removal and dehumidifier effectiveness). Performance comparisons between present cross-flow dehumidifier and another experimental cross-flow dehumidifier in the literature are carried out. The simulation is expected to help in optimizing of a cross flow dehumidifier. 相似文献
289.
Naeem Jan Abdul Nasir Mohsin S. Alhilal Sami Ullah Khan Dragan Pamucar Abdulrahman Alothaim 《Entropy (Basel, Switzerland)》2021,23(9)
Recently, there has been enormous development due to advancements in technology. Industries and enterprises are moving towards a digital system, and the oil and gas industries are no exception. There are several threats and risks in digital systems, which are controlled through cyber-security. For the first time in the theory of fuzzy sets, this research analyzes the relationships between cyber-security and cyber-crimes in the oil and gas sectors. The novel concepts of complex intuitionistic fuzzy relations (CIFRs) are introduced. Moreover, the types of CIFRs are defined and their properties are discussed. In addition, an application is presented that uses the Hasse diagram to make a decision regarding the most suitable cyber-security techniques to implement in an industry. Furthermore, the omnipotence of the proposed methods is explained by a comparative study. 相似文献
290.
Pratibha Pandey Fahad Khan Faisal Abdulrahman Alzahrani Huda A. Qari Mohammad Oves 《Molecules (Basel, Switzerland)》2021,26(18)
Rutin has been well recognized for possessing numerous pharmacological and biological activities in several human cancer cells. This research has addressed the inhibitory potential of rutin against the Jab1 oncogene in SiHa cancer cells, which is known to inactivate various tumor suppressor proteins including p53 and p27. Further, the inhibitory efficacy of rutin via Jab1 expression modulation in cervical cancer has not been yet elucidated. Hence, we hypothesized that rutin could exhibit strong inhibitory efficacy against Jab1 and, thereby, induce significant growth arrest in SiHa cancer cells in a dose-dependent manner. In our study, the cytotoxic efficacy of rutin on the proliferation of a cervical cancer cell line (SiHa) was exhibited using MTT and LDH assays. The correlation between rutin and Jab1 mRNA expression was assessed by RT-PCR analysis and the associated events (a mechanism) with this downregulation were then explored via performing ROS assay, DAPI analysis, and expression analysis of apoptosis-associated signaling molecules such as Bax, Bcl-2, and Caspase-3 and -9 using qRT-PCR analysis. Results exhibit that rutin produces anticancer effects via inducing modulation in the expression of oncogenes as well as tumor suppressor genes. Further apoptosis induction, caspase activation, and ROS generation in rutin-treated SiHa cancer cells explain the cascade of events associated with Jab1 downregulation in SiHa cancer cells. Additionally, apoptosis induction was further confirmed by the FITC-Annexin V/PI double staining method. Altogether, our research supports the feasibility of developing rutin as one of the potent drug candidates in cervical cancer management via targeting one such crucial oncogene associated with cervical cancer progression. 相似文献