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51.
Fozia Fozia Nisar Ahmad Zohra Aftab Buoharee Ijaz Ahmad Madeeha Aslam Abdul Wahab Riaz Ullah Shakeel Ahmad Amal Alotaibi Akash Tariq 《Molecules (Basel, Switzerland)》2022,27(14)
The goal of the research was to explore a new green method used to synthesize silver nanoparticles (Ag NPs) from an aqueous extract of Trigonella incise, which serves as a reducing and stabilizing agent. The obtained results showed an 85% yield of nanoparticles by using 2:5 (v/v) of 5% plant extract with a 0.5 M solution of AgNO3. Different techniques were used to characterize the synthesized Ag NPs, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and UV–visible spectroscopy. The UV–visible spectra of green synthesized silver nanoparticles showed maximum absorption at a wavelength of 440 nm. The FT-IR studies revealed the stretching oscillation frequency of synthesized silver nanoparticles in the absorption band near 860 cm−1. Similarly, the bending and stretching oscillation frequencies of the NH function group were assigned to the band in the 3226 cm−1 and 1647 cm−1 regions. The bending vibration of C-O at 1159 cm−1 confirmed the carbonyl functional group that was also assigned to the small intensity band in the range of 2361 cm−1. The X-ray diffraction analysis of Ag NPs revealed four distinct diffraction peaks at 2θ of 38°, 45°, 65° and 78°, corresponds to (111), (200), (220) and (311) of the face-centered cubic shape. The round shape morphology of Ag NPs with a mean diameter in the range 20–80 nm was analyzed via SEM images. Furthermore, the nanoparticles showed more significant antimicrobial activity against Salmonella typhi (S. typhi) and Staphylococcus aureus (S. aureus) with an inhibition zone of 21.5 mm and 20.5 mm at 6 μg/mL concentrations, respectively, once compared to the standard reference. At concentrations of 2 µg/mL and 4 µg/mL, all of the bacterial strains showed moderate activity, with inhibition zones ranging from 11 mm to 18.5 mm. Even at high concentrations of AgNPs, S. typhi showed maximum resistance. The best antifungal activity was observed by synthesized Ag NPs against Candida albicans (C. albicans) with 21 mm zone of inhibition, as compared to a standard drug which gives 22 mm of inhibition. Therefore, we conclude that the antibacterial and antifungal activities showed satisfactory results from the synthesized Ag NPs. 相似文献
52.
Malika Elouali Christophe Beyens Fatima Zohra Elouali Oleg Yaroshchuk Boucif Abbar Ulrich Maschke 《Macromolecular Symposia》2011,303(1):108-113
Summary: Electro-optical properties of Polymer Dispersed Liquid Crystal (PDLC) films doped with different nanoparticles (NPs), as well as optical and morphological properties of liquid crystal/NP mixtures have been investigated. PDLC films were prepared by UV irradiation of thiol-ene monomers and liquid crystal E7 in the presence of a small amount (0.5 and 1 wt.%) of nanoparticles. The presence of NP strongly influence the properties of liquid crystal/NP mixtures. In particular, adding nanoparticles results in a decrease of the glass and nematic-isotropic transition temperatures of the LC, suggesting that strong interactions occur between LC and nanoparticles. 相似文献
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Hussam Aldoori Zohra Bouberka Abdelouahab Nadim Yassine Agguine Said Eddarir Philippe Supiot 《Journal of Macromolecular Science: Physics》2020,59(10):609-620
AbstractDecabromodiphenylether (DBDE) is a brominated flame retardant which belongs to the group of polybromodiphenylethers (PBDEs) often used as a fire resistant additive in various well known polymeric systems like polystyrene, poly(acrylonitrile-butadiene-styrene) (ABS), polypropylene, etc. This compound can be considered as a persistent organic pollutant and presents certain risks for the environment owing to the fact that it is bioaccumulable and not biodegradable. A detailed investigation, described here, was carried out on the effect of ultraviolet/visible radiation on DBDE in ABS with the aim to study the photolytic reactions of this molecule in the solid state, in order to improve the economic and ecological treatment of brominated plastic waste from waste electrical and electronic equipment (WEEE). This study presents new aspects of the photochemical degradation of DBDE/ABS systems in the solid state. The photodegradation of DBDE in ABS was followed by Fourier transform infrared spectroscopy (FTIR) as well as by thermogravimetrical analysis (TGA). Good agreement was obtained for the results of both analytical methods in terms of the overall photolysis of DBDE. 相似文献
55.
Zohra Farnana 《Nonlinear Analysis: Theory, Methods & Applications》2010,73(9):2819-2830
Let X be a complete metric space equipped with a doubling Borel measure supporting a p-Poincaré inequality. We obtain various convergence results for solutions of double obstacle problems on open subsets of X. In particular, we consider a sequence of double obstacle problems with converging obstacles and show that the corresponding solutions converge as well. We use the convergence properties to define and study a generalized solution of the double obstacle problem. 相似文献
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Mohammed Bouchakour Yazid Derouiche Zohra Bouberka Christophe Beyens Lahcène Mechernène Farid Riahi 《Liquid crystals》2013,40(11):1527-1536
This contribution focuses on a detailed investigation of the relationship between the method of polymerisation/cross-linking, such as slow and rapid UV radiation, and high voltage accelerated electron beam (EB), and the obtained physical properties including phase diagrams, polymerisation and phase separation kinetics, morphologies and electro-optic responses of polypropyleneglycoldiacrylate (PPGDA) monomers, in the presence of the nematic liquid crystal E7. The longer the spacing between double bonds, the more rapid was the photopolymerisation under both UV systems; however, the reverse was proved under EB. More homogenous and regular morphologies were obtained under EB curing.The electro-optical responses of various polymer dispersed liquid crystals (PDLCs) systems exhibited remarkable differences between the UV-cured samples and those cured by the EB technique. It was found that the threshold and saturation voltages considerably increased in the case of the UV-cured systems. Other results involving the contrast ratio, which is higher for EB-cured systems, confirm their higher quality, although the rapid photopolymerisation UV source was employed, which slightly improved the electro-optical responses. Moreover, EB curing leads to high enough conversions without a photoinitiator, which may act as an impurity that might have a strong impact on the electro-optical performance of the obtained PDLCs. 相似文献
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Guennoun Z Piétri N Couturier-Tamburelli I Aycard JP 《The journal of physical chemistry. A》2005,109(37):8299-8305
Photoreactivity of cyanoacetylene with water was successively studied in cryogenic matrixes and in the solid phase at lambda > 120 nm. These studies were performed using FTIR spectroscopy, isotopic experiments and DFT calculations at the B3LYP/6-31G level of theory. The photolysis of cyanoacetylene complexed with water in an argon cryogenic matrix led to the formation of two products. The first one corresponds to the cyanoketene and the second to the HCN:C2O complex. Trapped in water ice and submitted to UV photolysis, the cyanoacetylene molecule shows great photoreactivity. Indeed, besides the cyanoketene and cyanhydric acid, we characterized and identified the formation of other compounds issued from the addition of water to the CC triple bond of cyanoacetylene. 相似文献
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探讨新疆柯尔克孜族和维吾尔族人群血管紧张素转化酶(ACE)基因rs1799752位点插入或缺失(I/D)多态性及其与2型糖尿病(TypeⅡdiabetes mellitus,T2DM)的关系.方法采用病例-对照的研究设计.采集无血缘关系、年龄性别匹配的新疆柯尔克孜族样本117例、维吾尔族样本127例,分为2型糖尿病组(T2DM)、糖耐量异常组(impaired glucose tolerance, IGT)和糖耐量正常组(normal glucose tolerance, NGT),以Hardy-Weinberg平衡检验确认研究样本的群体代表性,采用PCR技术检测ACE基因I/D多态性.结果(1)病例组与对照组ACE基因多态性的分布符合Hardy-Weinberg平衡定律,所选人群具有代表性;(2)柯尔克孜族DD型42.74%,ID型31.58%,II型26.50%,D和I 等位基因频率分别为58.115%和41.876%;维吾尔族DD型35.43%,ID型28.35%,II型36.22%,D和I 等位基因频率分别为49.626%和50.387%.(3)ACE基因频率差异在柯尔克孜族(χ2=70.11,P 〈0.01),维吾尔族(χ^2=35.11,P〈0.01)的糖调节异常组与糖耐量正常组间,分别具有统计学意义.在维吾尔族T2DM组中携带DD、ID、ID+DD基因型的个体较携带II基因型的个体发生糖代谢异常(T2DM+IGT)的危险性增加(OR=7.812,95%CI=3.135-19.607;OR=4.854,95%CI=1.835-12.821;OR=6.410,95%CI=2.865-14.286,携带D等位基因的个体较携带I等位基因的个体发生糖代谢异常(T2DM+IGT)的危险性增加(OR=4.444,95%CI=2.617-7.576),而柯尔克孜族DD、ID+DD基因型和D等位基因性对糖代谢异常(T2DM+IGT)的发病风险降低.结论ACE基因I/D多态性与新疆两个少数民族T2DM相关,ACE基因I/D多态性可能是维吾尔族T2DM的危险因素,柯尔克孜族的保护因素. 相似文献
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Tanzeel Zohra Muhammad Ovais Ali Talha Khalil Muhammad Qasim Zabta Khan Shinwari 《Natural product research》2019,33(1):136-142
The present study aims to evaluate phytochemical and pharmacological potentials of Dysphania ambrosioides (L.) Mosyakin & Clemants previously known as Chenopodium ambrosioides L. Extraction was carried out using 14 solvents with wide range of polarity to find out the best solvent system for each bioactivity. Total phenolic and flavonoids contents were measured colorimetrically and polyphenolics were quantified via HPLC-DAD analysis. The samples were screened for inhibitory potentials against free radicals, leishmania, cancer cell lines, protein kinase, α-Amylase enzymes and microbial strains. Among all solvents, maximum percentage of extract was recovered from methanol-water fraction of leaves. HPLC analysis exhibited the presence of rutin, myricetin and quercetin. In DPPH assay, methanolic leaf extract exhibited IC50 value of 130.7 ± 0.57 μg/mL. Considerable α-amylase inhibitory, cytotoxic, leishmanicidal and antimicrobial potentials were exhibited by plant samples. D. ambrosioides revealed significant antioxidant, cytotoxic, antimicrobial and anti-diabetic potentials and thus warrant further detailed studies to find novel drugs. 相似文献
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Czechoslovak Mathematical Journal - We present sufficient conditions for the existence of pth powers of a quasiho-mogeneous Toeplitz operator Teisθφ, where φ is a radial polynomial... 相似文献