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61.
Some amide derivatives of ethylene glycol‐bis(2‐aminoethylether)‐N,N,N′,N′‐tetraacetic acid (EGTA) have been prepared via their coupling with different aniline derivatives: amino, methyl, chloro, and hydroxy aniline. The EGTA amide derivatives were characterized, and their antimicrobial activities were evaluated. These antimicrobial agents have been investigated as photostabilizers for rigid poly(vinyl chloride) (PVC), suspension PVC, with a K value of 70. Their stabilizing efficiencies were evaluated by determining the percentage of weight loss, the intrinsic viscosities, as well as the amount of formed gel of the photodegraded PVC. The extent of discoloration and the change in the mechanical properties of the photodegraded polymer were also evaluated. The applied materials reduced the loss in weight that resulted from HCl evolution during photodegradation. Both viscosity and gel content measurements showed also a decrease in their values during the degradation process. The decrease in the percentage of gel formation upon applying the investigated photostabilizers reflects the lowering in extent of cross‐linking of the polymer, which implies preserving the mechanical properties of PVC. The extent of discoloration was also improved in the presence of the investigated compounds. The results have proved a greater stabilizing efficiencies of the antimicrobial EGTA amide derivatives than that of the phenyl salicylate ultraviolet (UV) absorber, which is commonly used as an industrial stabilizer. A radical mechanism was proposed to account for the stabilizing action of the investigated products. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
62.
Fereshteh Chekin Jahan‐Bakhsh Raoof Samira Bagheri Sharifah Bee Abd Hamid 《中国化学会会志》2012,59(11):1461-1467
We report a simple and effective strategy for fabrication of the nanocomposite containing chitosan (CS) and multiwall carbon nanotube (MWNT) coated on a glassy carbon electrode (GCE). The characterization of the modified electrode (CS‐MWNT/GC) was carried out using scanning electron microscopy (SEM) and UV–vis absorption spectroscopy. The electrochemical behavior of CS‐MWNT/GC electrode was investigated and compared with the electrochemical behavior of chitosan modified GC (CS/GC), multiwalled carbon nanotube modified GC (MWNT/GC) and unmodified GC using cyclic voltammetry (CV) and electron impedance spectroscopy (EIS). The chitosan films are electrochemically inactive; similar background charging currents are observed at bare GC. The chitosan films are permeable to anionic Fe(CN)63?/4? (FC) redox couple. Electrochemical parameters, including apparent diffusion coefficient for the Fe(CN)63?/4? redox probe at FC/CS‐MWNT/GC electrode is comparable to values reported for cast chitosan films. This modified electrode also showed electrocatalytic effect for the simultaneous determination of D‐penicillamine (D‐PA) and tryptophan (Trp). The detection limit of 0.9 μM and 4.0 μM for D‐PA and Trp, respectively, makes this nanocomposite very suitable for determination of them with good sensitivity. 相似文献
63.
M. A. Moharram Samira M. Rabie Aisha Y. Daghistani 《International Journal of Infrared and Millimeter Waves》1992,13(9):1433-1447
Infrared spectroscopy was applied for the investigation of the combined effects of -irradiation and heat on polyvinyl alcohol (PVA). The samples were exposed in an atmosphere of air at room temperature to doses ranging form 0.5 to 15 M rads. The obtained results revealed that exposure to -irradiation produces no considerable changes in the IR spectra of PVA apart from very slight changes in the intensities of the absorption bands. The crystallinity of the irradiated samples was determined by following the induced changes in the absorbances of the crystalline bands.The IR spectra of PVA samples heated at 180°C exhibited two absorption bands at 1580 and 1710 cm–1 due to carbonyl groups. Alken double bonds and possibly also carboxyl groups.IR spectroscopy was also used for the examination of the effect of time of heating in air or in vacuum and also the effect of quenching of the degree of crystallinity of -irradiated PVA. Careful examination of the IR spectra led to the conclusion that the temperature induced changes depend on time of heating, rate of cooling and -dosage used. The highest crystallinity was obtained by heating in vacuum at 140°C and quenching at –40°C. 相似文献
64.
Javad Razaviyan Razie Hadavi Rezvan Tavakoli Fereshteh Kamani Maliheh Paknejad Samira Mohammadi-Yeganeh 《Applied biochemistry and biotechnology》2018,186(4):1074-1089
Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer. Aberrant expression of genes in mTOR pathway and their targeting miRNAs plays an important role in TNBC. The aim of this study was to determine the expression of mTOR and S6K1 and their targeting miRNAs in breast cancer cell lines and clinical samples. miRNAs targeting 3′-UTR of mTOR and S6K1 mRNAs were predicted using bioinformatic algorithms. MDA-MB-231, MCF-7, and MCF-10A as well as 20 TNBC samples were analyzed for gene and miRNA expression using quantitative real-time PCR (RT-qPCR). A receiver operating characteristic (ROC) curve analysis was performed for evaluation of candidate miRNAs as diagnostic biomarkers. miR-96 and miR-557 targeting mTOR and S6K1 mRNAs, respectively, were selected, and miR-3182 was selected as the miRNA targeting both genes. The miRNAs were down-regulated in cell lines, while their target mRNAs were up-regulated. Similar findings were observed in clinical samples. The ROC curve analysis revealed decline in expression of these miRNAs. We suggest that miR-96, miR-557, and miR-3182 can be used as inhibitory agents for mTOR and S6K1 in TNBC-targeted therapy. 相似文献
65.
Infrared absorption spectroscopy has been applied for the identification of the minerals associated with natural goethite
(α-FeO·OH) from Saudi Arabia. The thermal transformation of natural goethite as well as the effects of the presence of the
associated minerals on the reaction products were investigated. The results revealed that at 300°C protohematite is formed
which at 600°C is slightly crystallized. Further recrystallization and hematite formation takes place at 1000°C. It was also
found that the presence of other minerals found in goethite samples has no effect on the reaction products. 相似文献
66.
67.
Enhanced properties of photovoltaic devices tailored with novel supramolecular structures based on reduced graphene oxide nanosheets grafted/functionalized with thiophenic materials
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Samira Agbolaghi Sara Ebrahimi Bakhshali Massoumi Saleheh Abbaspoor Raana Sarvari Farhang Abbasi 《Journal of Polymer Science.Polymer Physics》2017,55(24):1877-1889
For verifying the influence of donor–acceptor supramolecules on photovoltaic properties, different hybrids were designed and used in organic solar cells. In this respect, reduced graphene oxide (rGO) was functionalization with 2‐thiophene acetic acid (rGO‐f‐TAA) and grafted with poly(3‐dodecylthiophene) (rGO‐g‐PDDT) and poly(3‐thiophene ethanol) (rGO‐g‐PTEt) to manipulate orientation of poly(3‐hexylthiophene) (P3HT) assemblies. Face‐on, edge‐on, and flat‐on orientations were detected for assembled P3HTs on rGO and its functionalized and grafted derivatives, respectively. Alteration of P3HT orientation from face‐on to flat‐on enhanced current density (J sc), fill factor (FF), and power conversion efficiency (PCE) and thus J sc = 7.11 mA cm?2, FF = 47%, and PCE = 2.14% were acquired. By adding phenyl‐C71‐butyric acid methyl ester (PC71BM) to active layers composed of pre‐designed P3HT/rGO, P3HT/rGO‐f‐TAA, P3HT/rGO‐g‐PDDT, and P3HT/rGO‐g‐PTEt hybrids, photovoltaic characteristics further improved, demonstrating that supramolecules appropriately mediated in P3HT:PC71BM solar cells. Phase separation was more intensified in best‐performing photovoltaic systems. Larger P3HT crystals assembled onto grafted rGOs (95–143 nm) may have acted as convenient templates for the larger and more intensified phase separation in P3HT:PCBM films. The best performances were reached for P3HT:P3HT/rGO‐g‐PDDT:PCBM (J sc = 9.45 mA cm?2, FF = 54%, and PCE = 3.16%) and P3HT:P3HT/rGO‐g‐PTEt:PCBM (J sc = 9.32 mA cm?2, FF = 53%, and PCE = 3.11%) photovoltaic systems. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 1877–1889 相似文献
68.
Róbert Rajkó Samira Beyramysoltan Hamid Abdollahi János Eőri Gábor Pongor 《Analytica chimica acta》2015
In this paper the authors have investigated spectroscopic data analysis according to a recent development, i.e. the Direct Inversion in the Spectral Subspace (DISS) procedure. 相似文献
69.
70.
A combination of HBr and trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as anew and powerful oxidant was found effective for facile brotnination of different aromatic compounds at room temperature in water as a green solvent.Mild reaction conditions,high selectivity and yield,high reaction rate and non-toxicity are some of the major advantages of this synthetic protocol. 相似文献