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91.
92.
Lakovaara Matias Sirviö Juho Antti Ismail Mostafa Y. Liimatainen Henrikki Sliz Rafal 《Cellulose (London, England)》2021,28(9):5433-5447
Cellulose - In this work, deep eutectic solvent (DES) based on imidazole and triethylmethylammonium chloride was used as a reaction medium for the esterification of cellulose nanofiber (CNF) and... 相似文献
93.
Fabrication of a Single Layer and Bilayer Potentiometric Biosensors for Penicillin by Galvanostatic Entrapment of Penicillinase into Polypyrrole Films 总被引:1,自引:0,他引:1
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A single layer and bilayer potentiometric biosensors for the detection of penicillin have been developed. The favourable conditions that were established for the polypyrrole‐penicillinase ((PPy‐P’nase) single layer biosensor were 0.03 M pyrrole, 50 U/mL P’nase, 0.01 M penicillin, applied current density of 0.9 mA/cm2 and a polymerisation time of 40 s. The optimum conditions for the formation of the outer layer of the bilayer were: (a) 0.1 M Py, 19 U/mL P’nase, 0.01 M pen, current density of 0.9 mA/cm2 and a polymerisation time of 40 s. The minimum detectable penicillin concentration with the bilayer potentiometric biosensor was 0.3 µM and the linear concentration range was 7.5–146 µM. The average percentage recovery of penicillin that was found in amoxycillin 500 mg was 113±24 %. The determination of penicillin in milk was fraught with problems of non‐specific binding of penicillin to the milk. 相似文献
94.
The Use of Poly(Vinyl Alcohol) to Cross‐link Penicillinase for the Fabrication of a Penicillin Potentiometric Biosensor
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Chemically cross‐linked PVA films are permeable matrices for the fabrication of biosensors. PVA provides an attractive immobilisation method as it preserves the enzymatic activity. Penicillinase (P’nase) was cross‐linked with poly(vinyl alcohol) (PVA) and bovine serum albumin (BSA). The optimum conditions for the of BSA‐PVA‐P’nase film were: 2.5 % w/v PVA, 0.006 % w/v BSA, 2.4 mM penicillin (Pen) and 16 U/mL P’nase. The minimum detectable concentration was 1.7 µM. The linear concentration range obtained for the BSA‐PVA film was 7.5–283 µM. The BSA‐PVA P’nase biosensor detected penicillin in amoxycillin with an average percentage recovery of 97±12 %. Higher penicillin concentrations (10–20 ppm) were detected more successfully than lower concentrations (≤5 ppm). These results indicate that further work is required to enable the successful detection of lower penicillin concentrations such as 5 ppm. 相似文献
95.
由于抗生素的不当使用和细菌多药耐药的出现, 迫切需要开发新的抗菌剂. 本文制备了具有光热转换性能的正电荷半导体高分子材料及具有协同抗菌活性的半导体聚合物纳米粒子(SP-PPh3 NPs). SP-PPh3 NPs的光热转化效率为43.8%. 带正电荷的SP-PPh3 NPs可以附着在细菌上, 有助于将热量有效传递给细菌. 在热和正电荷的协同作用下, SP-PPh3 NPs对革兰氏阴性大肠杆菌(E. coli)和革兰氏阳性金黄色葡萄球菌(S. aureus)均具有抗菌活性, 其对二者的体外抑菌率分别为99.9%和98.6%. 此外, SP-PPh3 NPs具有良好的生物相容性, 对小鼠的主要器官几乎无副作用. 对细菌感染的小鼠皮肤伤口用SP-PPh3 NPs治疗12 d后, 伤口可以很好地愈合. 相似文献
96.
Ehab Abdel-Latif Mustafa M. Fahad Amr El-Demerdash Mohamed A. Ismail 《Journal of heterocyclic chemistry》2020,57(8):3071-3081
The chloroacetamide derivative, 1 , was used as a versatile precursor for the synthesis of various types of N-aryl-2-(benzothiazol-2-ylthio)acetamide derivatives. The reaction of 1 with 2-mercaptobenzothiazole followed by condensation reaction of the produced sulfide with phenylhydrazine, 2-cyanoacetohydrazide, and/or thiosemicarbazide furnished the conforming condensation products, 4 , 7 , and 10 , respectively. Treatment of the phenylhydrazone product, 4 , with Vilsmeier formylation reagent (POCl3/DMF) yielded the corresponding 4-formylpyrazole derivative, 5 . The thiosemicarbazone product, 10 , was reacted with ethyl bromoacetate to furnish the thiazolin-4-one derivative, 11 . The substitution reactions of chloroacetamide derivative, 1 , with 2-mercapto-4,6-dimethylnicotinonitrile and 6-amino-2-mercaptopyrimidin-4-ol, were explored to identify the sulfide products, 14 and 17 . Cyclization of 14 into its corresponding thieno[2,3-b]pyridine compound, 15 , was performed using sodium ethoxide. The thiosemicarbazone, 10 , and sulfide derivative, 14 , were found to be the most potent antibacterial compounds against Escherichia coli and Staphylococcus aureus, exhibiting growth inhibitory activities of 80.8% and 91.7%, respectively. Moreover, the thiosemicarbazone, 10 , displayed the most significant antioxidant activity with inhibitory activity of 82.6%, which comes close to the antioxidant activity of L-ascorbic acid. 相似文献
97.
The chalcone as (E)-1-([1,1′-biphenyl]-4-yl)-3-(3,4-dimethoxyphenyl)prop-2-en-1-one ( 3 ) was reacted with various active methylene compounds via Michael addition reaction under different conditions. In one hand, chalcone 3 reacted with isatin and glycine in one pot reaction via 1,3-dipolar cycloaddition reaction. On the other hand, chalcone 3 was also reacted with different N-nucleophiles via direct addition on the carbonyl group to award cyclic and/or acyclic products. Meanwhile, the reaction of chalcone 3 with S-benzylthiuronium chloride afforded the thio-Michael addition product. Chalcone 3 and 10 novel synthesized compounds were screened against two cell lines (HepG2 and MCF-7). Among of them, thiosemicarbazone 16 , oxime 14 and pyrimidine-2(1H)-thione 19 derivatives revealed an excellent activity against both cell lines (IC50 values = 6.79-12.91 μM), whereas thiosemicarbazone 16 (6.79 ± 0.5 and 7.58 ± 0.6 μM) showed the highest activity. 相似文献
98.
建立了水体、底泥、鱼体自然比例带皮肌肉和虾肌肉中氯硝柳胺(NIC)残留量测定的同位素稀释高效液相色谱-串联质谱(HPLC-MS/MS)法。水样经碱化后以乙酸乙酯提取,其他样品采用0.1%氨水乙腈提取,C_(18)粉进行样品净化。以乙腈-水为流动相,流速为0.3 mL/min,采用Thermo Hypersil Gold C_(18)(150 mm×2.1 mm,5μm)色谱柱进行分离,氯硝柳胺稳定同位素标记物(氯硝柳胺-~(13)C_6)为内标,选择反应监测(SRM)模式扫描,内标法定量。结果表明氯硝柳胺在0.2~200μg/L范围内呈良好线性关系,相关系数(r~2)不小于0.999 5。空白水样在2.5、25、250 ng/L加标水平下的平均回收率为90.5%~109%,相对标准偏差(RSD)为3.2%~11%,检出限(LOD)为1.0 ng/L,定量下限(LOQ)为2.5 ng/L;空白底泥、黄颡鱼自然比例带皮肌肉和克氏原螯虾肌肉在0.5、5.0、50μg/kg加标水平下的平均回收率分别为89.4%~113%、92.8%~110%和94.1%~107%,RSD分别为4.6%~12%、2.8%~11%和3.2%~9.3%,LOD均为0.2μg/kg,LOQ均为0.5μg/kg。该方法的灵敏度、准确度和选择性高,适用于实际水产养殖环境水体、底泥、鱼和虾中氯硝柳胺的残留分析。 相似文献
99.
Siti Aini Binti Nordin Mohan Prasath Mani Ahmad Zahran Md Khudzari Ahmad Fauzi Ismail 《International Journal of Polymer Analysis and Characterization》2020,25(3):126-133
AbstractWound healing is a complex process and it involves restoration of damaged skin tissues. Several wound dressings comprising naturally made substances are constantly investigated to assist wound healing. In this research, a new wound dressing based on polyurethane (PU) supplemented with essence of Channa striatus (CS) fish oil was made by electrospinning. Morphological study depicted the reduction in fiber diameter than PU with the addition of fish oil (0.552?±?0.109?μm for 8:1 v/v% and 0.519?±?0.196?μm 7:2 v/v%) than the pristine PU (0.971?±?0.205?µm). Fourier transform infrared spectroscopy (FTIR) analysis revealed the presence of fish oil in the composite as identified through increasing peak intensity. Fish oil resulted in the hydrophilic behavior (88?±?3 (8:1 v/v) and 70?±?6 (7:2 v/v)) as revealed in the contact angle analysis. Thermal gravimetric analysis (TGA) showed the superior thermal behavior of the wound dressing patch compared to the PU. Atomic force microscopy (AFM) analysis insinuated a decrease in the surface roughness of the pristine polyurethane with the added fish oil. Coagulation assays signified the delay in the blood clotting time portraying its anti-thrombogenic behavior. Hemolytic assay revealed the less toxic nature of the developed nanocomposites with the red blood cells (RBC’s) depicting its safety with blood. Hence, polyurethane nanofibers supplemented with fish oil made them as deserving candidates for wound dressing application. 相似文献
100.