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51.
Ni/Fe bimetallic nanoparticles were synthesized for treatment of Aroclor 1242, in order to evaluate their applicability for in situ remediation of groundwater and soil contaminated by polychlorinated biphenyls (PCBs). Our experimental results indicate that the total PCB concentration changed during the reduction of 3,5-dichlorobiphenyl (PCB 14), and biphenyl was produced as the final product. Initially, the concentration of 3-chlorobiphenyl (PCB 2) was increased in the prophase reaction and then slowly decreased, suggesting that Aroclor 1242 was first adsorbed by Ni/Fe nanoparticles, and then, the higher chlorinated congeners were converted gradually to the lower chlorinated congeners, and finally to biphenyl. The dechlorination efficiency of Aroclor 1242 reached approximately 80% at 25°C in just 5h, then 95.6% and 95.8% in 10h and 24h, respectively. The study revealed that high Ni/Fe nanoparticle dosage and high Ni content in Ni/Fe nanoparticles favor the catalytic dechlorination reaction. Moreover, a comparison of different types of catalysts on the dechlorination of Aroclor 1242 indicated that Ni/Mg and Mg powders showed a greater reactivity than Ni/Fe and Fe nanoparticles, respectively. 相似文献
52.
Two-phase CFD calculations, using a Lagrangian model and commercial code Fluent 6.2.16, were employed to calculate the gas
and droplet flows and film cooling effectiveness with and without mist on a flat plate. Two different three dimensional geometries
are generated and the effects of the geometrical shape, size of droplets, mist concentration in the coolant flow and temperature
of mainstream flow for different blowing ratios are studied. A cylindrical and laterally diffused hole with a streamwise angle
of 30° and spanwise angle of 0° are used. The diameter of film cooling (d) hole, and the hole length to diameter ratio (L/d) for both of geometries are 10 mm and 4, respectively. Also the blowing ratio ranges from 1.0 to 2.0, and the mainstream
Reynolds number based on the mainstream velocity and hole diameter (Re
d) is 6,219. The results are shown for different droplets diameters (1–10 μm), concentrations (1–5%) and mainstream temperatures
(350–500 K). The centreline effectiveness and distribution of effectiveness on the surface of cooling wall are presented. 相似文献
53.
Faiz Ali Khan Gowhar Ali Khista Rahman Yahya Khan Muhammad Ayaz Osama F. Mosa Asif Nawaz Syed Shams ul Hassan Simona Bungau 《Molecules (Basel, Switzerland)》2022,27(17)
The current work examined the pharmacological potential of a selected flavanone derivative 2-hydroxyflavanone as a promising remedy for the treatment and management of pain. The selected flavanone derivative (2-HF) was evaluated for its analgesic and anti-inflammatory potentials following standard pharmacological protocols including hot plate, acetic acid-induced writhing and tail immersion tests. Naloxone and pentylenetetrazol were used to evaluate the potential implication of GABAergic and opioidergic mechanisms. The anti-inflammatory potential of 2-HF was confirmed using carrageenan-, serotonin- and histamine-induced paw edema models as well as a xylene-induced ear edema model. Furthermore, the anti-neuropathic potential of 2-HF was tested using a cisplatin-induced neuropathic pain model. Our sample, at the tested concentrations of 15, 30 and 45 mg kg−1, showed considerable analgesic, anti-inflammatory effects, as well as efficacy against neuropathic pain. Naloxone and pentylenetetrazol at 1 and 15 mg kg−1 antagonized the anti-nociceptive activities of 2-hydroxyflavanone indicating the involvement of opioidergic and GABAergic mechanisms. In the static allodynia model, combination of gabapentin 75 mg kg−1 with 2-HF at 15, 30, 45 mg kg−1 doses exhibited considerable efficacy. In cold allodynia, 2-hydroxyflavanone, at doses of 15, 30 and 45 mg kg−1 and in combination with gabapentin (75 mg kg−1), demonstrated prominent anti-allodynic effects. The paw withdrawal latency was considerably increased in gabapentin + cisplatin treated groups. Moreover, cisplatin + 2-hydroxyflavanone 15, 30, 45 mg kg−1 showed increases in paw withdrawal latency. Likewise, considerable efficacy was observed for 2-hydroxyflavanone in thermal hyperalgesia and dynamic allodynia models. Our findings suggest that 2-hydroxyflavanone is a potential remedy for pain syndrome, possibly mediated through opioidergic and GABAergic mechanisms. 相似文献
54.
Research on Chemical Intermediates - In this study, a facile and rapid method was developed to synthesize intensely organoselenium compounds, namely ethylseleno[2,3-b]pyridine carboxylate,... 相似文献
55.
Nasim Najjarzadeh Leonidas Matsakas Ulrika Rova Paul Christakopoulos 《Molecules (Basel, Switzerland)》2020,25(24)
Xylan is one of the most abundant carbohydrates on Earth. Complete degradation of xylan is achieved by the collaborative action of endo-β-1,4-xylanases and β-d-xylosidases and a number of accessories enzymes. In filamentous fungi, the xylanolytic system is controlled through induction and repression. However, the exact mechanism remains unclear. Substrates containing xylan promote the induction of xylanases, which release xylooligosaccharides. These, in turn, induce expression of xylanase-encoding genes. Here, we aimed to determine which xylan degradation products acted as inducers, and whether the size of the released oligomer correlated with its induction strength. To this end, we compared xylanase production by different inducers, such as sophorose, lactose, cellooligosaccharides, and xylooligosaccharides in Fusarium oxysporum f. sp. lycopersici. Results indicate that xylooligosaccharides are more effective than other substrates at inducing endoxylanase and β-xylosidases. Moreover, we report a correlation between the degree of xylooligosaccharide polymerization and induction efficiency of each enzyme. Specifically, xylotetraose is the best inducer of endoxylanase, xylohexaose of extracellular β-xylosidase, and xylobiose of cell-bound β-xylosidase. 相似文献
56.
Abdolghafar Abolhosseini Shahrnoy Ali Reza Mahjoub Sudabeh Shokrollahi Nasim Ezzati Kristiane Elsner Christoph T. Koch 《应用有机金属化学》2020,34(7):e5645
In this study, a step-by-step method for the synthesis of platinum nanoparticles and copper(I) complex supported on mesoporous silica hollow spheres (Pt-MSHSs-Cu) is introduced. Scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption, energy-dispersive X-ray spectrometry, X-ray photoelectron spectroscopy, and elemental and thermogravimetric analyses were applied for characterization of the surface, structure, size, phase composition, and morphology of the synthesized materials. The characterized material, Pt-MSHSs-Cu, was used as an efficient and heterogeneous catalyst in the Sonogashira coupling reaction under different reaction conditions. In comparison with MSHSs, Cu(I)-functionalized MSHSs (MSHSs-Cu), and Pt-MSHSs samples, the Pt-MSHSs-Cu catalyst exhibited significantly increased catalytic performance with 91.50% yield. Therefore, the results obtained suggested a synergistic effect derived from platinum nanoparticles, MSHSs substrate, and copper(I) complex, which enhanced the rate of the Sonogashira coupling reaction. 相似文献
57.
58.
Fatemeh Safa Shams Abyaneh Mahboube Eslami Moghadam Adeleh Divsalar Davood Ajloo Moyaed Hosaini Sadr 《Applied biochemistry and biotechnology》2018,186(2):271-291
Methylglycine, also known sarcosine, is dramatically used in drug molecules and its metal complexes can interact to DNA and also do cleavage. Hence, to study the influence of methylglycine ligand on biological behavior of metal complexes, two water-soluble platinum (II) complexes with the formula cis-[Pt(NH3)2(CH3-gly)]NO3 and cis-[Pt(NH2-CH3)2(CH3-gly)]NO3 (where CH3-gly is methylglycine) have been synthesized and characterized by spectroscopic methods, molar conductivity measurements, and elemental analyzes. The anticancer activity of synthesized complexes was tested against human breast adenocarcinoma cell line of MCF7 using MTT assay and results showed excellent anticancer activity with Cc50 values of 126 and 292 μM after 24 h incubation time, for both complexes of cis-[Pt(NH3)2(CH3gly)]NO3 and cis-[Pt(NH2-CH3)2(CH3gly)]NO3, respectively. Also, the interaction between Pt(II) complexes with calf thymus DNA was extensively studied by means of absorption spectroscopy, fluorescence titration spectra displacement with ethidium bromide (EtBr), and circular dichroism studied in Tris-buffer. The obtained spectroscopic results revealed that two complexes can bind to highly polymerized calf thymus DNA cooperatively and denature at micromolar concentrations. The fluorescence data indicate that quenching effect for cis-[Pt(NH3)2(CH3gly)]NO3 (Ksv?=?9.48 mM?1) was higher than that of cis-[Pt(NH2-CH3)2(CH3gly)]NO3 (Ksv?= 1.98 mM?1). These results were also confirmed by circular dichrosim spectra. Consequently, docking data showed that cis-[Pt(NH3)2(CH3gly)]NO3 with more interaction energy binds on DNA via groove binding which is more compatible with experimental results. 相似文献
59.
In this work, we fabricated a new renewable syringe carbon paste electrode (SCPE) equipped with a motor rotary cutting blade and used for voltammetric determination of dipyridamole (DIP) in aqueous solution, at room temperature. The cutter rotates by a small electrical motor and easily renews the surface of the carbon paste electrode by removing the spotty surface. Electrochemical performance of the constructed electrode was investigated with cyclic voltammetry (CV) and compared to some other previously reported works. The new sensor showed several advantages such as excellent repeatability, high stability, good sensitivity and easily surface renewable. The results indicated that the presence of methyltrioctyl ammonium chloride (MTOAC) could remarkably enhance the oxidation of DIP due to feasible electrical conductivity properties in a phosphate buffer solution. At optimum conditions for the new syringe CPE, the square wave voltammetry (SWV) was used to measure the concentration of DIP in a linear range of 0.08–30.0 µM and a detection limit of 0.02 µM was obtained after 100 s of accumulation time. The sensor was then tested for the simple, rapid and sensitive electrochemical determination of DIP in real samples such as pharmaceutical formulations. 相似文献
60.
A.M. Shams El Din S.M. Abd El Haleem J.M. Abd El Kader 《Journal of Electroanalytical Chemistry》1975,65(1):335-349
A simple experimental arrangement was applied for the measurement and the evaluation of pitting corrosion currents operating under natural conditions. The feasibility of the procedure was examined by using Zn as a test metal, K2CrO4, Na2HPO4 and Na2WO4 as inhibitors, and Cl?, Br? and I? as pitting corrosion agents. Both the type and concentration of the inhibiting and corroding agents were varied in a programmed manner. In CrO42? and HPO42? solutions, the pitting corrosion currents started to flow after an induction period, which decreased with increase in the concentration of the attacking agent. In WO42? solutions, on the other hand, initially high currents were recorded due to the reduction of the agent to soluble, non-inhibiting species.In all solutions tested the corrosion current reached steady-state values which depended on the type and concentration of both the inhibiting and the aggressive anions. When keeping the inhibitor concentration constant, the corrosion current varied with the concentration of the aggressor according to: log icorr = a1 + b1 log cagg On the other hand, in solutions of constant aggressor concentration, with varying inhibitor amounts, the relation was: log icorr = a2 ? b2 log cinh where a1(a2) and b1(b2) are constants.The two equations were derived theoretically on the basis of competitive adsorption of the two counteracting agents on the surface of the metal. Comparison between the experimental values of a and b, with the corresponding terms of the theoretical equations was made.The aggressivity of the three tested anions decreases in the order Cl? > Br? > I?, whilst inhibition varied as CrO42? > HPO42? > WO42?. 相似文献