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991.
Fawaz?S.?Al-AnziEmail author Ali?Allahverdi 《Journal of Mathematical Modelling and Algorithms》2005,4(4):435-453
This research addresses the scheduling problem of multimedia object requests, which is an important problem in information
systems, in particular, for World Wide Web applications. The performance measure considered is the variance of response time
which is crucial as end users expect fair treatment to their service requests. This problem is known to be NP-hard. The literature
survey indicates that two heuristics have been proposed to solve the problem. In this paper, we present a new heuristic, a
hybrid evolutionary heuristic, which is shown to perform much better than the two existing ones, e.g., the overall average
errors of the existing ones are 1.012 and 2.042 while the error of the proposed hybrid evolutionary heuristic is 0.154. 相似文献
992.
Ali Mostafazadeh 《Czechoslovak Journal of Physics》2005,55(9):1157-1160
The main achievements of Pseudo-Hermitian Quantum Mechanics and its distinction from the indefinite-metric quantum theories
are reviewed. The issue of the non-uniqueness of the metric operator and its consequences for defining the observables are
discussed. A systematic perturbative expression for the most general metric operator is offered and its application for a
toy model is outlined.
Presented at the 3rd International Workshop “Pseudo-Hermitian Hamiltonians in Quantum Physics”, Istanbul, Turkey, June 20–22,
2005. 相似文献
993.
Our recent studies on the stem bark of Calophyllum mucigerum (Guttiferae) have yielded a new coumarin mucigerin, a prenylated xanthone cudraxanthone C and the common steroidal triterpenes friedelin and stigmasterol. Structural elucidations of these compounds were achieved using 1H NMR, 13C NMR, DEPT, COSY, HETCOR and HMBC experiments while MS gave the molecular masses. Cytotoxic assays using CEM-SS cell line (T-lymphoblastic leukemia) on the crude extracts of the stem bark indicated some activity. The crude extracts were also found to be moderately toxic against the larvae of Aedes aegypti. This article reports the isolation and identification of mucigerin as well as bioassay data. 相似文献
994.
Monosized poly(styrene/N-[3-(dimethylamino)propyl]methacrylamide/poly(ethylene glycol) ethyl ether methacrylate) [poly(St/PEG-EEM/DMAPM)] cationic nanoparticles were synthesized by emulsifier-free emulsion polymerization conducted in the presence of a cationic initiator, 2,2-azobis(2-methylpropionamidine) dihydrochloride (APDH or V-50). Particle sizes and surface charge densities were measured with a Zeta Sizer. The structure of the terpolymers was determined by Fourier transform IR and 1H NMR spectroscopies. The amounts of the main monomer (St), cationic comonomer (DMAPM), stabilizer (PEG-EEM), and initiator (APDH), and the water-to-monomer phase ratio were all effective on both the average size and the surface charge of the nanoparicles. The average particle size was in the range 75–400 nm depending on the recipe applied; it decreased on increasing the amount of DMAP or PEG-EEM or the water-to-monomer phase ratio in the feed, while it increased with increasing St or APDH content. These nanoparticles were quite monodisperse with a polydispersity index of 1.008–1.14. 相似文献
995.
Marine brown alga Dictyota dichotoma (Dictyotaceae) collected from Karachi coast of Arabian Sea yielded two new dolastane-diterpenoids named: dichototetraol (1) and dichotopentaol (3) along with 2 of the same skeleton as a new source. Their structures have been characterized with the aid of 2D-NMR spectroscopic techniques. 相似文献
996.
997.
Abstract (4-Methylpiperidine-dithiocarbamato-S,S′)triphenyltin(IV) derivative of 4-methyl-1-piperidine carbodithioic acid (4-MePCDTA) have been synthesized and characterized
by elemental, IR, multinuclear NMR (1H and 13C) and mass spectrometric studies. The crystal structure of the complex has been determined by X-ray single crystal analysis,
which shows unsymmetrical nature of the ligand towards coordination to tin. It crystallizes in monoclinic P21/c space group with the crystal cell parameters: a = 10.1863(10) ?, b = 21.200(2) ?, c = 11.7332(11) ?, β = 111.2020(10)°, Z = 4 and V = 2,362.2(4) ?3. The tin atom is coordinated to the two sulfur atoms of the dithiocarbamate ligand and three carbon atoms of the phenyl groups
are in distorted trigonal bipyramid geometry. This complex was tested for its antimicrobial activity against six different
plant and human pathogens. The screening results show that the complex exhibit higher antibacterial and antifungal activity
than the free ligand.
Index abstract
Synthesis, Spectroscopy, in vitro Biological Activity and X-Ray Structure of (4-Methylpiperidine-dithiocarbamato-S,S′)triphenyltin(IV)
Saira Shahzadi, Saqib Ali and Mohammmed Fettouhi
4-Methyl-1-piperidine carbodithioic acid behaves as anisobidentate ligand and chelates the tin atom by means of sulfur atoms
giving cis-trigonal bipyramid geometry around the tin atom.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
998.
Mahboob Nemati Mir Ali Farajzadeh Ali Mohebbi Fariba Khodadadeian Mohammad Reza Afshar Mogaddam 《Journal of separation science》2020,43(6):1119-1127
A stir bar sorptive extraction method coupled with deep eutectic solvent based solidification of floating organic droplets–dispersive liquid–liquid microextraction has been used for the simultaneous derivatization and extraction of some acidic pesticides in tomato samples. In this method, initially the analytes are adsorbed on a coated stir bar from tomato juice filled in a narrow tube. After extraction, the stir bar is removed and a water–miscible deep eutectic solvent is used to elute the analytes. Afterward, a derivatization agent and a water–immiscible deep eutectic solvent (as an extraction solvent) with melting point near to room temperature are added to the obtained eluant at µL–levels and the obtained mixture is rapidly injected into deionized water. Under the optimum conditions, the introduced method indicated high enhancement (1543–3353) and enrichment (2530–2999) factors, low limits of detection (7–14 ng/L) and quantification (23–47 ng/L), good linearity (r2 ≥ 0.9982), and satisfactory repeatabilities (relative standard deviation ≤12% for intra– and inter–day precisions at a concentration of 100 ng/L of each analyte). Finally, the proposed method was applied in analysis of the analytes in tomato samples. 相似文献
999.
AbstractThe whole plant, Tricholepis chaetolepis, powder was investigated using proximate and fluorescence analysis along with determining the extractive values. Total phenolics, flavonoids and total protein contents of n-hexane, chloroform and methanolic extracts of the whole plant were also determined. The anti-diabetic activity of all the three extracts of the plant was determined by in vitro alpha-amylase inhibition assay. The anti-oxidant potential was evaluated using Phosophomolybdenum and DPPH methods. The anti-inflammatory potential of all extracts were determined by carrageenan-induced rat paw oedema model. The evaluation of the plant extracts exhibited the anti-diabetic, anti-oxidant, and anti-inflammatory activities in dose dependent fashion. The research concludes that Tricholepis chaetolepis extracts contain phenol, flavonoids, and tannins that show observable anti-oxidant and anti-diabetic potential. It is also concluded that the methanol extract of the plant showed the maximum effect against inflammation induced by carrageenan in rat paw oedema as compared with n-hexane and chloroform extracts. 相似文献
1000.
Salwinder Singh Dhaliwal Vivek Sharma Arvind Kumar Shukla Janpriya Kaur Vibha Verma Prabhjot Singh Harkirat Singh Shams H. Abdel-Hafez Samy Sayed Ahmed Gaber Reham Ali Akbar Hossain 《Molecules (Basel, Switzerland)》2021,26(24)
Biofortification of pulse crops with Zn and Fe is a viable approach to combat their widespread deficiencies in humans. Lentil (Lens culinaris Medik.) is a widely consumed edible crop possessing a high level of Zn and Fe micronutrients. Thus, the present study was conducted to examine the influence of foliar application of Zn and Fe on productivity, concentration, uptake and the economics of lentil cultivation (LL 931). For this, different treatment combinations of ZnSO4·7H2O (0.5%) and FeSO4·7H2O (0.5%), along with the recommended dose of fertilizer (RDF), were applied to the lentil. The results of study reported that the combined foliar application of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at pre-flowering (S1) and pod formation (S2) stages was most effective in enhancing grain and straw yield, Zn and Fe concentration, and uptake. However, the outcome of this treatment was statistically on par with the results obtained under the treatment ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage. A single spray of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage enhanced the grain and straw yield up to 39.6% and 51.8%, respectively. Similarly, Zn and Fe concentrations showed enhancement in grain (10.9% and 20.4%, respectively) and straw (27.5% and 27.6% respectively) of the lentil. The increase in Zn and Fe uptake by grain was 54.8% and 68.0%, respectively, whereas uptake by straw was 93.6% and 93.7%, respectively. Also the benefit:cost was the highest (1.96) with application of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage. Conclusively, the combined use of ZnSO4·7H2O (0.5%) + FeSO4·7H2O (0.5%) at S1 stage can contribute significantly towards yield, Zn and Fe concentration, as well as uptake and the economic returns of lentil to remediate the Zn and Fe deficiency. 相似文献