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81.
Touqeer Sohail Tian Tang Ben Nadler 《International Journal of Solids and Structures》2013,50(16-17):2678-2690
Adhesion of a particle with a substrate in presence of electrostatic interaction is an appealing area of research because of its significance in many biological and industrial applications. In this work, we study an interesting problem in which a charged flexible particle located in an electrolytic environment adheres to an oppositely charged rigid substrate due to the electrostatic attraction between them. The particle is a membrane filled with incompressible fluid and can undergo large deformation. Continuum theories are used to model the mechanics of the membrane and the electric potential in the electrolytic solution. The developed model allows us to examine the nature of the coupling between the electrostatic interaction and the deformation of the membrane. In particular, the deformation of the membrane causes non-uniform distribution of charges on its surface and significant electrostatic repulsion between these charges. This repulsion is most pronounced within and near the contact zone and provides a source of resistance to its further deformation and contact formation. As a result, the coupling between electrostatics and deformation is most significant for moderate deformation and becomes weaker for very large deformation. The relation between the total electrostatic adhesive force and the contact area shows similar scaling , where to the classical Hertz theory of contact at small deformation, but the value of n increases as deformation increases. The dependence of this relation on the Debye length of the solution and the initial fluid pressure in the membrane is also investigated. 相似文献
82.
Shiwei He Sohail S. Chaudhry Zhonglin Lei Wang Baohua 《Annals of Operations Research》2009,168(1):169-179
We study a vendor selection problem in which the buyer allocates an order quantity for an item among a set of suppliers such
that the required aggregate quality, service, and lead time requirements are achieved at minimum cost. Some or all of these
characteristics can be stochastic and hence, we treat the aggregate quality and service as uncertain. We develop a class of
special chance-constrained programming models and a genetic algorithm is designed for the vendor selection problem. The solution
procedure is tested on randomly generated problems and our computational experience is reported. The results demonstrate that
the suggested approach could provide managers a promising way for studying the stochastic vendor selection problem.
The authors would like to thank the referees for providing constructive comments that led to an improved version of the paper.
Also, this research was partially supported by grants from National Natural Science Foundation (60776825)—China, 863 Programs
(2007AA11Z208)—China, Doctorate Foundation (20040004012)—China, Villanova University Research Sabbatical Fall 2006, and the
National Science Foundation (0332490)—USA. 相似文献
83.
Ullah Naeem Nadeem Sohail Khan Arif Ullah 《Journal of Thermal Analysis and Calorimetry》2021,143(6):4169-4181
Journal of Thermal Analysis and Calorimetry - In this study, numerical simulations of natural convection in a partially heated rectangular cavity containing water-based copper oxide nanofluid... 相似文献
84.
85.
Muhammad Sohail Noora Barzkar Philippe Michaud Saeid Tamadoni Jahromi Olga Babich Stanislav Sukhikh Rakesh Das Reza Nahavandi 《Molecules (Basel, Switzerland)》2022,27(12)
Lignocellulose, the main component of plant cell walls, comprises polyaromatic lignin and fermentable materials, cellulose and hemicellulose. It is a plentiful and renewable feedstock for chemicals and energy. It can serve as a raw material for the production of various value-added products, including cellulase and xylanase. Cellulase is essentially required in lignocellulose-based biorefineries and is applied in many commercial processes. Likewise, xylanases are industrially important enzymes applied in papermaking and in the manufacture of prebiotics and pharmaceuticals. Owing to the widespread application of these enzymes, many prokaryotes and eukaryotes have been exploited to produce cellulase and xylanases in good yields, yet yeasts have rarely been explored for their plant-cell-wall-degrading activities. This review is focused on summarizing reports about cellulolytic and xylanolytic yeasts, their properties, and their biotechnological applications. 相似文献
86.
Noora Barzkar Ruilong Sheng Muhammad Sohail Saeid Tamadoni Jahromi Olga Babich Stanislav Sukhikh Reza Nahavandi 《Molecules (Basel, Switzerland)》2022,27(11)
The cell wall of brown algae contains alginate as a major constituent. This anionic polymer is a composite of β-d-mannuronate (M) and α-l-guluronate (G). Alginate can be degraded into oligosaccharides; both the polymer and its products exhibit antioxidative, antimicrobial, and immunomodulatory activities and, hence, find many commercial applications. Alginate is attacked by various enzymes, collectively termed alginate lyases, that degrade glycosidic bonds through β-elimination. Considering the abundance of brown algae in marine ecosystems, alginate is an important source of nutrients for marine organisms, and therefore, alginate lyases play a significant role in marine carbon recycling. Various marine microorganisms, particularly those that thrive in association with brown algae, have been reported as producers of alginate lyases. Conceivably, the marine-derived alginate lyases demonstrate salt tolerance, and many are activated in the presence of salts and, therefore, find applications in the food industry. Therefore, this review summarizes the structural and biochemical features of marine bacterial alginate lyases along with their applications. This comprehensive information can aid in the expansion of future prospects of alginate lyases. 相似文献
87.
88.
Malik Saadullah Muhammad Asif Arshad Farid Faiza Naseem Sheikh Abdur Rashid Shakira Ghazanfar Muhammad Muzammal Sohail Ahmad Yousef A. Bin Jardan Huda Alshaya Muhammad Hamzah Saleem Shafaqat Ali Charles Oluwaseun Adetunji Sania Arif 《Molecules (Basel, Switzerland)》2022,27(8)
Breynia distachia is a plant of genus Breynia belonging to family Phyllanthaceae. This study was conducted to isolate and examine the anti-inflammatory attributes of the roots of Breynia distachia. Methanol extract from roots were prepared by simple maceration. For phytochemical studies, isolation, purification, structure elucidation, metal analysis, total phenolic content, and solubility test were done by chromatographic and spectroscopic techniques. Anti-inflammatory activity was evaluated by cotton pallet edema model and carrageenan paw edema model, and antioxidant potential was evaluated by DPPH, FRAP, and ABTS antioxidants assays. Metal analysis of BD.Me revealed the presence of Na > Mg > K > Mn > Fe = Zn in respective order. Four phytochemicals such as gallic acid, quercetin, sinapic acid, and p-coumaric acid are found in Breynia distachia. Quercetin is present in relatively larger quantity, and shows antioxidant activity by reducing the ferric iron to ferrous iron. Novel distachionate shows high antioxidant activity in ABTS assay by reducing reactive oxygen species. Quantitative or qualitative analysis performed by HPLC indicates the ascending peaks or presence of secondary products (metabolites) respectively. Histopathology analysis of liver, spleen, heart, and kidney was done, revealing mild inflammations in spleen and liver, and no cytotoxicity in heart and kidney. Oral administration of BD.Me and ditachionate significantly inhibits the carrageenan and cotton pellet-induced paw edema in 1st and 2nd h with (ns = p > 0.05) than control. After 3rd, 4th, 5th, and 6th h, BD.Me and ditachionate showed inhibition of paw edema in a highly significant (*** = p < 0.001) manner as compared to control. In cotton-pellet edema model, distachionate shows a %inhibition of 57.3% at a dose level of 5 mg/kg. Docking values obtained from distachionate-COX-2 complex suggest a potent inhibitor evaluated for this protein. The distachionate shows effective anti-inflammatory activity. Methanol extracts of roots showed significant lipoxygenase inhibitory activity by IC50 values of 155.7 ± 0.55 and 132.9 ± 0.33 μg/mL. Data from various in vitro and in vivo models suggest that novel distachionate isolated from Breynia distachia shows strong antioxidant and anti-inflammatory activities; it should be further studied for the exploration of its medicinal potential. 相似文献
89.
Xia?Cheng Yao?Cen Guanhong?Xu Fangdi?Wei Menglan?Shi Xiaoman?Xu Muhammad?Sohail Qin?HuEmail author 《Mikrochimica acta》2018,185(2):144
The authors describe a fluorometric aptamer based assay for adenosine triphosphate (ATP). It is based on the use of carbon dots (CDs) and graphene oxide (GO). The resultant CD-aptamer is adsorbed on the surface of GO via π-stacking and hydrophobic interaction, and the fluorescence of CD-aptamer is quenched via fluorescence resonance energy transfer (FRET) between CDs and GO. If ATP is present, it will bind to the aptamer and the CD-aptamer will be desorbed from GO. This will suppress FRET and the fluorescence of the CDs is restored. Under the optimal conditions and at typical excitation/emission wavelengths of 358/455 nm, the assay has a 80 pM detection limit and a linear range that extends from 0.10 to 5.0 nM concentrations of ATP. The method was successfully applied to the determination of ATP in yogurt samples. This method can also be conceivably applied to the detection of other analytes for which appropriate aptamers are available. 相似文献
90.
Muhammad Iqbal Saqib Ali Manzar Sohail Muhammad N. Tahir Paul A. Anderson 《中国化学会会志》2019,66(12):1619-1627
Two new copper(II) carboxylate complexes with 2,2′‐bipyridine and para‐nitrophenyl acetate (complex 1 ) and phenyl acetate (complex 2 ) have been synthesized; isolated in quantitative yield; and characterized using fourier‐transform infrared spectroscopy (FT‐IR), electron paramagnetic resonance, absorption spectroscopy, electrochemistry, and powder and single crystal X‐ray diffraction (XRD) techniques. Being mononuclear, the geometry around copper in complex 1 is a Jahn–Teller distorted octahedral, while complex 2 is binuclear with slightly distorted square pyramidal geometry around both copper ions. Powder XRD indicated several peaks in spectra of both complexes, which coincided with their theoretical spectra. FT‐IR results of the carboxylate stretching frequency were in accordance with the single crystal structure data. Electron paramagnetic resonance spectra of complexes 1 and 2 yielded g┴ values of 2.06161 and 2.24623 and 1.94959, respectively, indicating a localized electron in b1 (d x2–y2‐orbital). Ultra‐violet (UV)–visible spectroscopy and electrochemistry helped in characterization, as well as in deoxyribonucleic acid (DNA)‐binding ability of the complexes, yielding DNA‐binding constant values = 1.351 × 104 and 1.361 × 104 and 1.820 × 104 and 2.426 × 104 M?1, respectively, for complexes 1 and 2 . The complexes demonstrate good biological potential. 相似文献