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排序方式: 共有390条查询结果,搜索用时 15 毫秒
381.
Imdad Ullah Ahmad Naveed Afzal Shah Amin Badshah Zia-ur-Rehman Gul Shahzada Khan Arif Nadeem 《Journal of surfactants and detergents》2014,17(2):243-251
Two new cationic surfactants, N-(dodecanoyl(ethylammonio)carbonothioyl)-N-ethylbenzenaminium bromide and N-(dodecanoyl(ethylammonio)carbonothioyl)-N-ethyl-N-phenylbenzenaminium bromide were synthesized with a high yield by the reaction of appropriate amounts of lauryl chlorides, potassium thiocyanate, amine and alkyl halides. The structures were characterized by 1H-NMR, 13C-NMR, FTIR and UV–Vis spectroscopy. Cyclic, square wave and differential pulse voltammetry were used to investigate the electrochemical fate of both surfactants over a wide pH range. 相似文献
382.
A thermal hydraulic study of convective heat transfer in 3 × 3 square array of heated vertical cylinders is carried out using computational fluid dynamics (CFD). Two different CFD approaches were used, i.e., full structural details (FSD) and porous media modeling (PMM). The computational requirement in PMM declined significantly due the porous media approximation. The PMM only gives the overall flow and temperature field. In the FSD model all the geometry details are presented without any approximation. The PMM and FSD results are compared to experimental data. In general, the prediction of temperature profiles from both PMM and FSD agreed well with the experimental data. 相似文献
383.
Nadeem Akhter Ajit Wilson Reeby Thomas Fatema Al-Rashed Shihab Kochumon Areej Al-Roub Hossein Arefanian Ashraf Al-Madhoun Fahd Al-Mulla Rasheed Ahmad Sardar Sindhu 《International journal of molecular sciences》2021,22(19)
IL-8/MCP-1 act as neutrophil/monocyte chemoattractants, respectively. Oxidative stress emerges as a key player in the pathophysiology of obesity. However, it remains unclear whether the TNF-α/oxidative stress interplay can trigger IL-8/MCP-1 expression and, if so, by which mechanism(s). IL-8/MCP-1 adipose expression was detected in lean, overweight, and obese individuals, 15 each, using immunohistochemistry. To detect the role of reactive oxygen species (ROS)/TNF-α synergy as a chemokine driver, THP-1 cells were stimulated with TNF-α, with/without H2O2 or hypoxia. Target gene expression was measured by qRT-PCR, proteins by flow cytometry/confocal microscopy, ROS by DCFH-DA assay, and signaling pathways by immunoblotting. IL-8/MCP-1 adipose expression was significantly higher in obese/overweight. Furthermore, IL-8/MCP-1 mRNA/protein was amplified in monocytic cells following stimulation with TNF-α in the presence of H2O2 or hypoxia (p ˂ 0.0001). Synergistic chemokine upregulation was related to the ROS levels, while pre-treatments with NAC suppressed this chemokine elevation (p ≤ 0.01). The ROS/TNF-α crosstalk involved upregulation of CHOP, ERN1, HIF1A, and NF-κB/ERK-1,2 mediated signaling. In conclusion, IL-8/MCP-1 adipose expression is elevated in obesity. Mechanistically, ROS/TNF-α crosstalk may drive expression of these chemokines in monocytic cells by inducing ER stress, HIF1A stabilization, and signaling via NF-κB/ERK-1,2. NAC had inhibitory effect on oxidative stress-driven IL-8/MCP-1 expression, which may have therapeutic significance regarding meta-inflammation. 相似文献
384.
Nadeem Sayyed Abdul Hafeez Fahad A. Al-Abbasi Asma B Omer Shareefa A. AlGhamdi Amira M. Alghamdi Rayan A. Sheikh Imran Kazmi 《European Journal of Lipid Science and Technology》2023,125(9):2200205
Erucic acid is a single unsaturated fatty acid that falls under the omega-9 fatty acid family. It was suggested to treat Wistar rats with lipopolysaccharide (LPS)-induced memory impairment and minimize cognitive impairment. A total of 30 animals were randomized: group I was normally treated group, group II was administered with LPS, group III was treated with LPS along with erucic acid at the dose of 10 mg kg–1 p.o.–1, group IV was treated with LPS along with erucic acid at 20 mg kg–1 p.o.–1 and group V was the erucic acid per se group provided at the dose of 20 mg kg–1 p.o.–1 per se. Behavioral tests were evaluated by using the Morris water maze and Y-maze. Biochemical analysis including acetylcholine esterase (AChE), choline acetyltransferase (ChAT), glutathione (GSH), catalase activity (CAT), superoxide dismutase (SOD), and nitric oxide (NO) along with proinflammatory mediators tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), caspase 3, and neuroinflammatory biomarker (nuclear factor kappa B-NF-κB) were measured. Erucic acid produced substantial behavioral improvement in the Y-maze test, including spontaneous alterations and reduced latency time during acquisition, and a longer duration of time in the consolidation phase undergoing the MWM test. Furthermore, erucic acid improved the AChE, proinflammatory markers, and oxidative stress as well as restoring endogenous antioxidant levels, ChAT, caspase 3, and NF-κB levels. Erucic acid may be a therapeutic component for conditions related to memory disorders such as memory impairment, enhances memory functioning, and protects against neuronal damage. 相似文献
385.
S. Rahman K. Nadeem M. Anis-ur-Rehman M. Mumtaz S. Naeem I. Letofsky-Papst 《Ceramics International》2013,39(5):5235-5239
We synthesized soft magnetic spinel ferrite ZnMg-ferrite (Zn1?xMgxFe2O4, where x=0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) nanoparticles using the co-precipitation method. Structural and magnetic properties have been studied in detail. XRD revealed that the structure of these nanoparticles is spinel with crystallite size lies in the range 21–31 nm. Lattice parameter decreases with increasing Mg concentration due to the smaller ionic radius of the Mg2+ ion. FTIR spectroscopy also confirmed the formation of spinel ferrite by showing the characteristic absorption bands at 420 cm?1 and 545 cm?1. Vibrational band of metal ion at tetrahedral site (Mtet.) with oxygen ions (O–Mtet.–O) is shifted toward higher wave numbers with the increase of Mg concentration. The magnetization showed an increasing trend with increasing Mg concentration due to the rearrangement of cations at tetrahedral and octahedral sites, while the corecivity remained constant due to the soft nature of the ferrite composition. Both structural and magnetic properties of ZnMg-ferrite nanoparticles strongly depend upon Mg2+ cation doping percentage. 相似文献
386.
Sidra Nawaz Muhammad Sarfraz Asif Ali Qaiser Muneerah Alomar Soumaya Gouadria Amal Ali BaQais 《应用聚合物科学杂志》2024,141(8):e54971
Gas separation process is an effective method for capturing and removing CO2 from post-combustion flue gases. Due to their various essential properties such as ability to improve process efficiency, polymeric membranes are known to dominate the market. Trade-off between gas permeability and selectivity through membranes limits their separation performance. In this study, solution casting cum phase separation method was utilized to create polyethersulfone-based composite membranes doped with carbon nanotubes (CNTs) and silico aluminophosphate (SAPO-34) as nanofiller materials. Membrane properties were then examined by performing gas permeation test, chemical structural analysis and optical microscopy. While enhancing membranes CO2 permeance, SAPO-34 and CNTs mixture improved their CO2/N2 selectivity. By carefully adjusting membrane casting factors such as filler loadings. Using Taguchi statistical analysis, their carbon capture efficiency was improved. The improved mixed-matrix membrane with loading of 5 wt% CNTs and 10 wt% SAPO-34 in PES showed highly promising separation performance with a CO2 permeability of 319 Barrer and an ideal CO2/N2 selectivity of 12, both of which are within the 2008 Robeson upper bound. A better mixed-matrix membrane with outstanding CO2/N2 selectivity and CO2 permeability was produced as a result of the synergistic effect of adding two types of fillers in optimized loading. 相似文献
387.
Ahmad Niaz Qaiser Jawed Malik Sher Muhammad Tahir Shamim Shoaib Asghar 《Coloration Technology》2011,127(4):211-216
A study on bioscouring of cotton yarn with the pectinase enzyme was carried out and the results compared with the usual alkali scoured material. The results indicate that the bioscoured yarn has lower percentage of non‐cellulosic constituents (impurities), higher tenacity, higher absorbency and the same whiteness after hydrogen peroxide bleaching as compared with the Solomatic bleached yarn. A similar study on cotton fabric indicates that a combined desizing and bioscouring is not feasible at least at ambient temperature. More work, however, is required to compare bioscouring followed by bleaching with the Solomatic or two step scouring and bleaching methods. One interesting finding is that the efficiency of washing of the desized fabric improves on adding ethylene diamine tetraacetic acid sequestrating agent in the wash liquor. Additional advantages of bioscouring are lower energy cost and more easily biodegradable effluent in comparison to alkali scouring. 相似文献
388.
In the present study, an attempt has been made to improve cell supportive property of chitosan/nano beta tri‐calcium phosphate (β‐TCP) composite scaffolds by modification of scaffold surface with fibrin using ethyl‐3‐(3‐dimethylaminopropyl) carbodimide (EDC) as crosslinking agent. The developed fibrin conjugated chitosan/nano β‐TCP composite scaffolds possess desired pore size and porosity in the range of 45–151 µm and 81.4 ± 4.1%, respectively. No significant change in compressive strength of scaffolds was observed before and after fibrin conjugation. The calculated compressive strength of fibrin conjugated and non‐conjugated chitosan/nano β‐TCP scaffolds are 2.71 ± 0.14 MPa and 2.67 ± 0.11 MPa, respectively. Results of cell culture study have further shown an enhanced cell attachment, cell number, proliferation, differentiation, and mineralization on fibrin conjugated chitosan/nano β‐TCP scaffold. The uniform cell distribution over the scaffold surface and cell infiltration into the scaffold pores were assessed by confocal laser scanning microscopy. Furthermore, higher expression of osteogenic specific genes such as bone sialo protein, osteonectin, alkaline phosphatase, and osteocalcin (OC) on fibrin conjugated scaffolds was observed when compared to scaffolds without fibrin. Altogether, results indicate the potentiality of developed fibrin conjugated composite scaffolds for bone tissue engineering applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41534. 相似文献
389.
Ahmad Hussain Muhammad Adnan Qaiser Ji Zhang Shan‐Tao Zhang Yiping Wang Ying Yang Zhiguo Liu Guoliang Yuan 《Journal of the American Ceramic Society》2017,100(8):3522-3529
The 0‐3 type CaBi4Ti4O15:30 wt%BiFeO3 composite shows much better high‐temperature piezoelectric properties than the single‐phase CaBi4Ti4O15 or BiFeO3 ceramics. The composite with 0‐3 type connectivity exhibits a high density of 7.01 g/cm3, a saturated polarization of 21.5 μC/cm2 and an enhanced piezoelectric d33 of 25 pC/N. After the poled composite was annealed at 600°C, its d33 is 21 pC/N at room temperature. Resistance of the composite decreases slowly from 109 ohm at 20°C to ~105 ohm at 500°C. Furthermore, the poled composite shows strong radial and thickness dielectric resonances at 20°C‐500°C. 相似文献
390.
QuratulAin Nadeem Muhammad Rizwan Rohama Gill Muhammad Rafique Muhammad Shahid 《应用聚合物科学杂志》2016,133(5)
Novel electrically conductive composites were synthesized by incorporating Cu coated alumina (Cu‐Al2O3) powder prepared via electroless plating technique as filler (0–21wt %) into polystyrene‐b‐methylmethacrylate (PS‐b‐PMMA) and polystyrene (PS) matrices. XRD analysis depicted maximum Cu crystallite growth (26.116 nm~ plating time 30 min) onto Al2O3 along with a significant change in XRD patterns of composites with Cu‐Al2O3 inclusion. SEM–EDX analyses exhibited uniform Cu growth onto Al2O3 and confirmed presence of Cu, Al, Pd in Cu‐Al2O3, and C, O, Al, Cu, and Pd in PS‐b‐PMMA and PS composites. Increasing filler loadings exhibited increased electrical conductivity (5.55 × 10?5S/cm for PS‐b‐PMMA; 5.0 × 10?6S/cm for PS) with increased Young's modulus (1122MPa for PS‐b‐PMMA; 1053.9MPa for PS) and tensile strength (27.998MPa for PS‐b‐PMMA; 30.585MPa for PS) and decreased % elongation. TGA demonstrated increased thermal stability and DTG revealed two‐step degradation in composites while DSC depicted pronounced increment in Tg of Cu‐Al2O3/PS‐b‐PMMA with increased filler loading. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42939. 相似文献