Nanomaterials-based photoelectrochemical (PEc) detection is becoming a rapidly-developing analytical technique in chemical and biological assays due to its unique advantages of easy miniaturization, high sensitivity, ...
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Nanomaterials-based photoelectrochemical (PEc) detection is becoming a rapidly-developing analytical technique in chemical and biological assays due to its unique advantages of easy miniaturization, high sensitivity, and rapid turn-around time. Herein, a molecularly imprinted polymer-assisted PEc sensor based on ZnO/c nanocomposite was suc-cessfully fabricated for the highly sensitive and selective determination of chloramphenicol (cAP). Benefiting from the hydrophilic functional groups (-OH,-cOOH) and large surface area of bio-templated ZnO/c nanocomposite, the tight grafting of MIP with excellent recognition ability on substrate is easier and more stable than traditional PEc sensor, thus significantly increasing the performance. Under optimal conditions, the PEc sensor exhibited significant cAP de-tection performance in the range of 0.01-5000 ng mL-1 with a detection LOD of 5.08 pg mL-1(S/N = 3) and success-fully applied to the detection of cAP in milk sample. Our results show that ZnO/c nanocomposite and MIP can act as an efficient photo-responsible matrix to fabricate PEc sensor, providing important application potentials for pollutants control in food and environment.
The nematode c. elegans has a contingent of five sod genes, one of the largest among aerobic organisms. Earlier studies revealed each of the five sod genes is capable of making perfectly active SOD proteins in heterol...
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The nematode c. elegans has a contingent of five sod genes, one of the largest among aerobic organisms. Earlier studies revealed each of the five sod genes is capable of making perfectly active SOD proteins in heterologous expression systems therefore none appears to be a pseudogene. Yet deletion of the entire contingent of sod genes fails to impose any effect on the survival of c. elegans except these animals appear more sensitive to extraneously applied oxidative stress conditions. We asked how many of the five sod genes are actually making active SOD enzymes in c. elegans through the usage of in-gel SOD activity analysis and by using KcN as a selective inhibitor against cu-ZnSOD enzyme(s). Here we provide evidence that out of the five SOD proteins only the mitochondrial SOD is active in the water-soluble fraction of c. elegans extracts albeit at an apparently much lower activity than the multiple active SODs in D. melanogaster and E. coli. We had no opportunity to test the activity of Sod-4a isoform which is possibly a membrane-bound form of SOD. The mutant analysis further confirmed that among the two mitochondrial SOD proteins, SOD-2 is the only naturally active SOD in c. elegans.
To lower the cost and preparation period of c/c-Zrc-Siccomposites, the uneven-density c/ccomposites (with a high density in the inner region and low density in the surface region) are designed and prepared by therma...
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To lower the cost and preparation period of c/c-Zrc-Siccomposites, the uneven-density c/ccomposites (with a high density in the inner region and low density in the surface region) are designed and prepared by thermal gradient cVI process, followed by local modification of Zrc-Siccomposite ceramics by precursor infiltration -pyrolysis (PIP) mothed to improve the anti-ablation performance. The ablation tests show that the Siccon-tents have a great influence on the microstructure of ZrO2 grains at the ablation center by adjusting the ablation temperature and the melting point of ZrO2 grains. Results prove that about 20 wt% Sic is optimum for the Zrc-Siccomposite ceramics to perform best during the ablation and modify the uneven c/ccomposites prepared in this work. Besides, the dense c/c matrix would stop the liquid ZrO2-SiO2 phase from running off, and in return, the dense ZrO2-SiO2 phase would sink into the surface within the ablated region, which could protect the carbon fibers of the surface region and the dense c/c matrix beneath.
The hollow SiO2/c hybrid was prepared through a combined soft-templated sol-gel approach and calcination method, and applied in poly(butylene adipate-co-terephthalate) (PBAT) film. The initial elongation at breaks and...
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The hollow SiO2/c hybrid was prepared through a combined soft-templated sol-gel approach and calcination method, and applied in poly(butylene adipate-co-terephthalate) (PBAT) film. The initial elongation at breaks and tensile strength of the PBAT film loaded 4phr SiO2/c hybrid were increased by 34% and 71%, respectively, compared to that containing naked SiO2. The combination of carbon with SiO2 mainly facilitated the homoge-nous dispersion and better substantial interfacial adhesion in PBAT matrix. Furthermore, a release experiment of the SiO2/c/1130 showed that a small amount of [3-[3-(2H-Benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxyphenyl]-1-oxopropyl]-hydroxypoly(oxo-1,2-ethanediyl) (UV1130) was absorbed by the SiO2/c hybrid, which could furtherly improve the dispersion of hybrid in PBAT matrix and UV resistance. The work provides a promising method to reinforce PBAT composites and prepare UV-resistant PBAT films simultaneously.
To improve the mechanical properties of fiber-reinforced ceramic-matrix composites (cMcs), it is necessary to establish the relationship between the composite's constituent properties and macro mechanical properti...
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To improve the mechanical properties of fiber-reinforced ceramic-matrix composites (cMcs), it is necessary to establish the relationship between the composite's constituent properties and macro mechanical properties. In this paper, a hysteresis-based micromechanical method was adopted to obtain the constituent properties of four different types of 3D needle-punched c/Siccomposites. Hysteresis-based damage parameters (i.e., inverse tangent modulus (ITM), hysteresis width, residual strain, hysteresis modulus, and damage factor) were derived from the hysteresis theory. Through analysis of the experimental monotonic tensile and cyclic hysteresis curves, the composite's constituent properties (i.e., interface properties and thermal residual stress, etc.) and mechanical properties (i.e., first matrix cracking stress, interface debonding stress, and ultimate tensile strength, etc.) were obtained. Relationship between the composite's constituent properties and mechanical properties was established. Using the estimated composite's constituent properties and developed micromechanical constitutive models, the experimental monotonic and cyclic tensile loading/unloading curves were predicted.
Rh-based catalysts have attracted much attention due to their ability to efficiently break c-c bonds in ethanol oxidation reaction(EOR), while pure Rh catalyst have low EOR activity. It is important to improve the EOR...
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Rh-based catalysts have attracted much attention due to their ability to efficiently break c-c bonds in ethanol oxidation reaction(EOR), while pure Rh catalyst have low EOR activity. It is important to improve the EOR activity of Rh-based catalyst. Herein, we have been successfully synthesized carbon supported Rh, Rh-Pb, and Rh-Ru alloy catalysts. The catalytic activity of RhPb/c for ethanol oxidation is 0.96 mA/cm2, which is 8 times than that of Rh/c. The steady-state current density of RhPb/c at 0.5 V is 17 and 20 times higher than that of RhRu/c and Rh/c, respectively. The results show that adding a small portion of lead significantly enhanced the Rh-based catalyst activity, stability, and anti-poisoning ability during EOR in alkaline media. Moreover, the Tafel slope of RhPb/ccatalyst for EOR is 118 mVdec-1, which is similar with that of Pt/c (116 mVdec-1), while the Tafel slope of RhRu/c is 77 mVdec-1, similar to that of Rh/c(87 mVdec-1). The cO-stripping potential of RhRu/c, Rh/c and RhPb/c is 0.535 V, 0.573 V and 0.601 V, respectively. combined with the cyclic voltammetry, chronoamperometry, cO-stripping and Tafel analysis, it is concluded that for RhRu/ccatalyst, the improvement of EOR is mainly attributed to the bifunctional mechanism, while for RhPb/ccatalyst, the ensemble effect and the electronic effect of Pb is essential to the improvement of EOR.
Physicochemical and catalytic properties of Pd/ccatalysts before and after the deactivation as a result of a dimethylbenzylamine debenzylation-acylation reaction are compared. A comprehensive analysis conducted by a ...
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Physicochemical and catalytic properties of Pd/ccatalysts before and after the deactivation as a result of a dimethylbenzylamine debenzylation-acylation reaction are compared. A comprehensive analysis conducted by a number of methods (chemisorption, X-ray photoelectron spectroscopy, electron microscopy, X-ray diffraction) showed that a tenfold loss of the catalyst activity in the reaction conducted in soft conditions (atmospheric H-2 pressure, 25 degrees c) is related to the formation of a nanoscale graphite phase. While this phenomenon is common for high temperature reactions, it is first discovered at low temperatures.
The influence of nitrate (NO3- -N) concentrations (40, 80 mg/L marked as R40 and R80) and carbon/nitrogen (c/N) ratios (0.8,1.5, 2.5, 3.5, 4.5) on nitrite (NO2- -N) accumulation in partial denitrification (PD) process...
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The influence of nitrate (NO3- -N) concentrations (40, 80 mg/L marked as R40 and R80) and carbon/nitrogen (c/N) ratios (0.8,1.5, 2.5, 3.5, 4.5) on nitrite (NO2- -N) accumulation in partial denitrification (PD) process was investigated. The results proved that R40-3.5 and R80-2.5 systems showed the optimal NO2- -N contents and nitrate-tonitrite transformation ratio (NTR) values of 14.88, 29.77 mg/L and 52.87 %, 59.12 % with strong resistance to low temperature (12.5-3.8 degrees c). Batch tests displayed the NO2- -N accumulation mechanism via substrate transformations, and the metabolic pathways of nitrogen and carbon for PD and complete denitrification were also compared. Based on the Monod equation, the half-saturation constants of 58.33 and 61.20 mg/L were estimated with zero-order reaction for NO3- -N and NO2- -N reduction, showing a tighter affinity to NO3- -N concentration. Proteobacteria, Bacteroidota, Acidobacteriota and chloroflexi were the four dominant phyla with total percentages of 85.16-94.55 % and 90.81-96.85 % in R40 and R80 groups, while Thauera, Flavobacterium contributing to NO2- N accumulation reached up to 42.79 % and 52.13 % in the R40-3.5 and R80-2.5 systems. The above discussion demonstrated that lower c/N ratio and higher NO3- -N concentration were more favorable for the PD formation.
Oxygen Reduction Reaction (ORR) is one of the key electrochemical reactions, especially in Polymer Electrolyte Fuel cells (PEFcs). In this work, the reaction pathway and intermediate species such as molecular-type oxy...
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Oxygen Reduction Reaction (ORR) is one of the key electrochemical reactions, especially in Polymer Electrolyte Fuel cells (PEFcs). In this work, the reaction pathway and intermediate species such as molecular-type oxygen during ORR were discussed. High energy resolution X-ray absorption fine structure spectra at the Pt L3-edge were obtained to observe the electronic structure of Pt catalyst. carbon-supported Pt nanoparticles as powder catalysts were used for measurement as more realisticconditions, and the species adsorbed on the Pt nanoparticles were analyzed while controlling under the potentials in acidic electrolyte solution with N2 or O2 gas bubbling. Molecular-type oxygen adsorption species is observed only in the O2-bubbled electrolyte solution. This intermediate adsorption species is assigned to a hydrogen superoxide.
The development of seven-membered heterocyclic scaffolds, namely benzothiazepine, has gained much recognition in mild environmentally friendly conditions such as low temperature and short reaction time due to its vast...
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The development of seven-membered heterocyclic scaffolds, namely benzothiazepine, has gained much recognition in mild environmentally friendly conditions such as low temperature and short reaction time due to its vast medicinal pertinence. A novel class of [1,5]-benzothiazepine-c -fi-D-glycosides was synthe-sized in a facile one-pot method from a, fi- unsaturated -b -c-glycosidic ketones where the use of p-TSA had shown a better result. The fi-anomeric forms of the c-glycosidiccompounds were assigned from 1 H NMR spectroscopy. Studies propose that the series of [1,5]-benzothiazepine-based fi-c-glycosides showed moderate anti-oxidant activities with maximum inhibitory activity of 60%. The second generation [1,5]-benzothiazepine-fi-c-glycoside (piperonal derivative) with 1,3-benzodioxole-substitution (compound 10d ) especially showed excellent anti-oxidant characteristics at all concentrations ranging from 100 to 600 mu g/mL.(c) 2023 Elsevier B.V. All rights reserved.
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