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11.
Adnan Khan Muhammad Waleed 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(5):432-459
In this article, a deterministic model is formulated to perform a thorough investigation of the transmission dynamics of influenza. In particular, our model takes into account the effects of medication as well as hospitalization. An in-depth stability analysis of the model is performed, and it is subsequently shown that the model is locally, as well as globally asymptotically stable, when R0 > 1. It is also shown that there exists a unique endemic equilibrium whenever R0 > 1. After estimating the effective contact rate, we estimate the basic reproduction number, using both an ordinary least squares and generalized least squares methodology. We also estimated confidence intervals for the effective contact rate using parametric bootstrapping. Furthermore, we perform uncertainty and sensitivity analysis to recognize the impact of crucial model parameters on R0. In addition, using ideas from the optimal control theory, optimal medication and hospitalization strategies are proposed to eliminate the disease. 相似文献
12.
Dr. Waleed Alsalahi Dr. Adam W. Augustyniak Dr. Włodzimierz Tylus Prof. Dr. Anna M. Trzeciak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(6):e202103538
The new nanocomposites, Pd/C/ZrO2, PdO/ZrO2, and Pd/PdO/ZrO2, were prepared by thermal conversion of Pd@UiO-66-Zr−NH2 (MOF) in nitrogen or air atmosphere. The presence of Pd nanoparticles, uniformly distributed on the ZrO2 or C/ZrO2 matrix, was evidenced by transmission electron microscopy, scanning electron microscopy (SEM), Raman and X-ray Photoelectron Spectroscopy (XPS) methods. All pyrolysed composites retained the shape of the MOF template. They catalyze carbonylative Suzuki coupling under 1 atm CO with an efficiency significantly higher than the original Pd@UiO-66-Zr−NH2. The most active PdO/ZrO2 composite, formed benzophenone with TOF up to 1600 h−1, while by using Pd@UiO-66-Zr−NH2, much lower TOF values, 51–95 h−1, were achieved. After the reaction, PdO/ZrO2 was recovered with the same composition and catalytic activity. Very good results were also obtained in the transfer hydrogenation of benzophenones to alcohols with Pd/C/ZrO2 and PdO/ZrO2 catalysts under microwave irradiation. 相似文献
13.
Hadad GM El-Gindy A Mahmoud WM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(3):655-663
High-performance liquid chromatography (HPLC) and multivariate spectrophotometric methods are described for the simultaneous determination of ambroxol hydrochloride (AM) and doxycycline (DX) in combined pharmaceutical capsules. The chromatographic separation was achieved on reversed-phase C(18) analytical column with a mobile phase consisting of a mixture of 20mM potassium dihydrogen phosphate, pH 6-acetonitrile in ratio of (1:1, v/v) and UV detection at 245 nm. Also, the resolution has been accomplished by using numerical spectrophotometric methods as classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS-1) applied to the UV spectra of the mixture and graphical spectrophotometric method as first derivative of the ratio spectra ((1)DD) method. Analytical figures of merit (FOM), such as sensitivity, selectivity, analytical sensitivity, limit of quantitation and limit of detection were determined for CLS, PLS-1 and PCR methods. The proposed methods were validated and successfully applied for the analysis of pharmaceutical formulation and laboratory-prepared mixtures containing the two component combination. 相似文献
14.
S. Waleed Noor 《Integral Equations and Operator Theory》2012,73(4):589-602
Given a strictly increasing sequence ${\Lambda = (\lambda_n)}$ of nonnegative real numbers, with ${\sum_{n=1}^\infty \frac{1}{\lambda_n}<\infty}$ , the Müntz spaces ${M_\Lambda^p}$ are defined as the closure in L p ([0, 1]) of the monomials ${x^{\lambda_n}}$ . We discuss how properties of the embedding ${M_\Lambda^2\subset L^2(\mu)}$ , where?μ is a finite positive Borel measure on the interval [0, 1], have immediate consequences for composition operators on ${M^2_\Lambda}$ . We give criteria for composition operators to be bounded, compact, or to belong to the Schatten–von Neumann ideals. 相似文献
15.
New eight lanthanide metal complexes were prepared. These complexes were characterized by elemental analysis, molar conductivity measurements, spectral analysis (1H NMR, FT-IR, UV–vis), luminescence and thermal gravimetric analysis. All Ln(III) complexes were 1:1 electrolytes as established by their molar conductivities. The microanalysis and spectroscopic analysis revealed eight-coordinated environments around lanthanide ions with two nitrate ligands behaving in a bidentate manner. The other four positions were found to be occupied with tetradentate LIII ligand. Tb–LIII and Sm–LIII complexes exhibited characteristic luminescence emissions of the central metal ions and this was attributed to efficient energy transfer from the ligand to the metal center. The LIII and Ln–LIII complexes showed antibacterial activity against a number of pathogenic bacteria. 相似文献
16.
Suleiman Qaseem Abu-Ein Sayel M. Fayyad Waleed Momani Mamdouh Al-Bousoul 《Heat and Mass Transfer》2009,46(2):137-145
The present work provides a detailed thermodynamic analysis of a 10 kW solar absorption refrigeration system using ammonia-water
mixtures as a working medium. This analysis includes both first law and second law of thermodynamics. The coefficient of performance
(COP), exergetic coefficient of performance (ECOP) and the exergy losses (ΔE) through each component of the system at different operating conditions are obtained. The minimum and maximum values of COP
and ECOP were found to be at 110 and 200°C generator temperatures respectively. About 40% of the system exergy losses were
found to be in the generator. The maximum exergy losses in the absorber occur at generator temperature of 130°C for all evaporator
temperatures. A computer simulation model is developed to carry out the calculations and to obtain the results of the present
study. 相似文献
17.
Abdou O. Abdelhamid Sobhi M. Gomha Waleed A. M. A. El‐Enany 《Journal of heterocyclic chemistry》2019,56(9):2487-2493
Sodium salt of 3‐hydroxy‐1‐(1‐aryl‐5‐methylpyrazolyl)propenone derivatives was used as a precursor for synthesis of various fused azolopyrimidine ring systems as pyrazolopyrimidines, triazolopyrimidines, and pyrimidobenzimidazoles following many procedures. The identity of the prepared compounds was elucidated by their spectral data and elemental analyses. The in vitro antimicrobial activity of 13 new compounds was evaluated, and many derivatives showed good to moderate activity. 相似文献
18.
Microfluidic paper-based analytical devices (µPADs) have attracted much attention over the past decade because they offer clinicians the ability to deliver point-of-care testing and onsite analysis. Many of the advantages of µPADs, however, are limited to work in a laboratory setting due to the difficulties of processing data when using electronic devices in the field. This review focuses on the use of µPADs that have the potential to work without batteries or with only small and portable devices such as smartphones, timers, or miniaturized detectors. The µPADs that can be operated without batteries are, in general, those that allow the visual judgment of analyte concentrations via readouts that are measured in time, distance, count, or text. Conversely, a smartphone works as a camera to permit the capture and processing of an image that digitizes the color intensity produced by the reaction of an analyte with a colorimetric reagent. Miniaturized detectors for electrochemical, fluorometric, chemiluminescence, and electrochemiluminescence methods are also discussed, although some of them require the use of a laptop computer for operation and data processing. 相似文献
19.
The reaction between bleached banana pulp and pure maleic anhydride (MA) was investigated. The reaction was conducted in a reactor in the presence of xylene used as a solvent and sodium hypophosphite as catalyst. The appearance of infrared absorption bands at 1891 and 1708 cm?1 indicated that MA chemically reacted by esterification with bleached banana pulp. However, evidence of an esterification reaction was obtained between cellulose and MA. The production of fast‐responding bulk hydrogel with a high swelling ratio was also investigated. This hydrogel was synthesized first by the formation of maleated acrylamide particles and then by the graft copolymerization of the particles with cellulose. The maleated acrylamide particles were characterized with mass spectroscopy, and the formed hydrogl was characterized by FT‐IR. The esterification reaction between bleached banana pulp and maleated acrylamide was also studied. Steam absorption for bulk hydrogel, maleated acrylamide‐treated bleached banana pulp, MA‐treated cellulose and bleached banana pulp is higher than the steam absorption for untreated cellulose and bleached banana pulp. Compared with treated bleached banana pulp and cellulose, the hydrogel had very high swelling ratios and much faster swelling rates attributed to the collaboration of the ionized particles and bulk hydrogel. The number of ionic maleated acrylamide groups in the hydrogel affected the swelling behavior. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
20.
A series of cellulose-phenol-formaldehyde (LCPF) and cellulose-urea-formaldehyde (CUF) resins were produced using banana waste. Detailed structure and quantitative information was provided by FT-IR and mass spectroscopy. The main interests were the ability to use banana waste as a source of cellulose in the condensation reaction. Functionality of CPF and structure of CUF were investigated. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献