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361.
Babar Murtaza Asghar Abbas Aqeel Aslam M. S. Akhtar S. Bashir Mariam Khalid Muhammad Moazzam Naseer 《Research on Chemical Intermediates》2016,42(5):4161-4170
The presently available therapies for type 2 diabetes have not been able to achieve normoglycemic status in a majority of the patients which may be either due to the limitations of the drug itself or its side effects. In an effort to develop potent and safe oral antidiabetic agents, 4-ethyloxychalcone, which was found to be the most potent antiglycating agent in our previous study, has been evaluated for its in vivo hypoglycemic activity using an alloxanized diabetic rat model. The diabetes was induced in rats by injection of intraperitoneal alloxan. However, the oral route was used for the administration of 4-ethyloxychalcone. A significant glucose-lowering effect (P < 0.05) comparable with the standard glibenclamide has been observed for 4-ethyloxychalcone in an oral glucose tolerance test. 4-Ethyloxychalcone also produced a significant decrease (P < 0.05) in fasting blood glucose levels during the 42 days of treatment. Furthermore, a significant lowering (P < 0.05) of glycated hemoglobin (HbA1C ) level was also shown by 4-ethyloxychalcone after 42 days of treatment. Thus, 4-ethyloxychalcone might be regarded as a potential hypoglycemic agent that can act as a platform for the development of future antidiabetic drugs. 相似文献
362.
In this paper, we prove in general that the homotopy perturbation method (HPM) proposed in 1998 is only a special case of
the homotopy analysis method (HAM) profound in 1992 when ħ = −1. Besides, by using the thin film flows of Sisko and Oldroyd
6-constant fluids on a moving belt as examples, we show that the solutions given by HPM (Siddiqui, A.M., Ahmed, M., Ghori,
Q.K.: Chaos Solitons and Fractals (2006) in press) are divergent, and thus useless. However, by choosing a proper value of
the auxiliary parameter ħ, we give convergent series solution by means of the HAM. These two examples also show that, different
from the HPM and other traditional analytic techniques, the HAM indeed provides us with a simple way to ensure the convergence
of the solution. 相似文献
363.
Conditions are derived for the linearizability via invertible maps of a system of n second-order quadratically semi-linear differential equations that have no lower degree lower order terms in them, i.e.,
for the symmetry Lie algebra of the system to be sl(n + 2, ℝ). These conditions are stated in terms of the coefficients of the equations and hence provide simple invariant criteria
for such systems to admit the maximal symmetry algebra. We provide the explicit procedure for the construction of the linearizing
transformation. In the simplest case of a system of two second-order quadratically semi-linear equations without the linear
terms in the derivatives, we also provide the construction of the linearizing point transformation using complex variables.
Examples are given to illustrate our approach for two- and three-dimensional systems. 相似文献
364.
Hong?Ma Xiaoyu?Liu Xudong?Wang Xinran?Li Chengduan?Yang Anam?Iqbal Weisheng?Liu Jiping?Li Wenwu?QinEmail author 《Mikrochimica acta》2017,184(1):177-185
We describe a highly sensitive glucose probe based on carbon dots modified with MnO2. A strong reduction of the green fluorescence of the carbon dots (CDs) happened due to the surface energy transfer (SET) from CDs to the deposited MnO2. In the presence of H2O2 (formed via enzymatic oxidation of glucose), fluorescence is restored because the MnO2 nanosheets are reduced to form colorless Mn(II) ions. These findings were used to design a fluorometric glucose assay that has a detection limit as low as 44 nM (at an S/N ratio of 3). 相似文献
365.
Muhammad Asghar Abdul Nabi 《International journal of environmental analytical chemistry》2017,97(3):276-288
A simple and sensitive chemiluminescence (CL) procedure is proposed for the determination of cyromazine (CYR) using flow injection technique. CYR has strong enhancing effect on the CL reaction of diperiodatoargentate-(III) complex (DPA) in H2SO4 medium. The CL intensity with solid phase extraction (SPE) technique and with and without using online ion exchange resin column (IERC; OH-form) was proportional to the concentration of CYR over the range 0.1–200, 10–1000 and 2–2500 µg L–1 (R2 = 0.9974, 0.9980 and 0.9990, n = 7 each), respectively. Under the conditions, the limits of detection (S/N = 3) 0.029, 2.5 and 0.5 µg L–1, relative standard deviations (n = 3) 1.9–3.6%, 1.4–2.7% and 1.0–3.0% and sample throughputs were 120, 80 and 120 h–1. The effect of reagents concentration, flow rate, sample loop volume, photomultiplier voltage and IERC length was optimised. The mean results for natural water samples analysed by the proposed method were not significantly different at 95% confidence limit with the previously reported HPLC method. Interference from chloride ions could be eliminated by using SPE procedure or incorporating an in-line IERC. The CL mechanism of DPA–H2SO4–CYR system was also discussed briefly. 相似文献
366.
Ammarah Raees Umer Farooq Muzamil Hussain Waseem Asghar Khan Fozia Bashir Farooq 《理论物理通讯》2021,73(6):65801
The aspiration of this research is to explore the impact of non-similar modeling for mixed convection in magnetized second-grade nanofluid flow. The flow is initiated by the stretching of a sheet at an exponential rate in the upward vertical direction. The buoyancy effects in terms of temperature and concentration differences are inserted in the $x$-momentum equation. The aspects of heat and mass transfer are studied using dimensionless thermophoresis, Schmidt and Brownian motion parameters. The governing coupled partial differential system (PDEs) is remodeled into coupled non-similar nonlinear PDEs by introducing non-similar transformations. The numerical analysis for the dimensionless non-similar partial differential system is performed using a local non-similarity method via bvp4c. Finally, the quantitative effects of emerging dimensionless quantities on the non-dimensional velocity, temperature and mass concentration in the boundary layer are conferred graphically, and inferences are drawn that important quantities of interest are substantially affected by these parameters. It is concluded that non-similar modeling, in contrast to similar models, is more general and more accurate in convection studies in the presence of buoyancy effects for second-grade non-Newtonian fluids. 相似文献
367.
Ali Asghar Foroughi Roohollah Abbasi Shureshjani 《Central European Journal of Operations Research》2017,25(4):889-905
Data envelopment analysis (DEA) is a non-parametric technique to assess the performance of a set of homogeneous decision making units (DMUs) with common crisp inputs and outputs. Regarding the problems that are modelled out of the real world, the data cannot constantly be precise and sometimes they are vague or fluctuating. So in the modelling of such data, one of the best approaches is using the fuzzy numbers. Substituting the fuzzy numbers for the crisp numbers in DEA, the traditional DEA problem transforms into a fuzzy data envelopment analysis (FDEA) problem. Different methods have been suggested to compute the efficiency of DMUs in FDEA models so far but the most of them have limitations such as complexity in calculation, non-contribution of decision maker in decision making process, utilizable for a specific model of FDEA and using specific group of fuzzy numbers. In the present paper, to overcome the mentioned limitations, a new approach is proposed. In this approach, the generalized FDEA problem is transformed into a parametric programming, in which, parameter selection depends on the decision maker’s ideas. Two numerical examples are used to illustrate the approach and to compare it with some other approaches. 相似文献
368.
Hamid Reza Shaterian Fahimeh Khorami Azita Amirzadeh Majid Ghashang Asghar Hosseinian 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2584-2595
Alumina sulfuric acid as a recyclable catalyst conducts the transformation of various types of alcohol, phenols, and oximes with hexamethyldisilazane (HMDS) to the corresponding O-trimethylsilylated compounds in good to excellent yields under mild and ambient conditions with short reaction times. The method is highly selective for the conversion of primary alcohols in the presence of secondary and tertiary alcohols. Additionally, the catalyst can be easily recovered and reused at least eight times without detectable loss of reactivity. 相似文献
369.
Nizar El Guesmi Guillaume Berionni Basim H. Asghar 《Monatshefte für Chemie / Chemical Monthly》2013,144(10):1537-1545
370.
Basim H. Asghar 《Monatshefte für Chemie / Chemical Monthly》2008,139(10):1191-1195
Kinetic and equilibrium studies are reported of the reactions of 1,3,5-trinitrobenzene (TNB) with a series of o-substituted anilines in dimethyl sulfoxide (DMSO) in the presence of 1,4-diazabicyclo[2.2.2.]octane (DABCO). The pK
a
values in DMSO for the aniline derivatives were measured using the proton-transfer equilibrium with 2,4-dinitrophenol. Kinetic studies are
compatible with a two-step process involving initial nucleophilic attack on TNB by amine to give a zwitterionic intermediate which may transfer an acidic proton to DABCO to yield the anionic product. The results indicate steric hindrance to proton transfer in reactions involving 2,6-disubstituted
anilines.
Correspondence: Basim H. Asghar, Department of Chemistry, Faculty of Applied Sciences, Umm Al-Qura University, P.O. Box 9569,
Makkah, Saudi Arabia. 相似文献