Cu-Doped ZnO Nanoparticles for Non-Enzymatic Glucose Sensing

Copper-doped zinc oxide nanoparticles (NPs) Cu_xZn_1−xO (x = 0, 0.01, 0.02, 0.03, and 0.04) were synthesized via a sol-gel process and used as an active electrode material to fabricate a non-enzymatic electrochemical sensor for the detection of glucose. Their structure, composition, and chemical properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) and Raman spectroscopies, and zeta potential measurements. The electrochemical characterization of the sensors was studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Cu doping was shown to improve the electrocatalytic activity for the oxidation of glucose, which resulted from the accelerated electron transfer and greatly improved electrochemical conductivity. The experimental conditions for the detection of glucose were optimized: a linear dependence between the glucose concentration and current intensity was established in the range from 1 nM to 100 μM with a limit of detection of 0.7 nM. The proposed sensor exhibited high selectivity for glucose in the presence of various interfering species. The developed sensor was also successfully tested for the detection of glucose in human serum samples.     

Solid-phase extraction clean-up procedure for the analysis of PAHs in lichens

A clean-up procedure based on a solid-phase extraction column was optimized for determination of polycyclic aromatic hydrocarbons (PAHs) in lichen extracts to remove co-extracted compounds from the matrix in the final extract. Several kinds of solid phases were evaluated: normal phase (-NH₂ and alumina), strong anion exchange and reversed phase. The -NH₂ columns were the most effective by using a packed solid bed of 500?mg. The lichen raw extract was loaded on the column previously conditioned with dichloromethane and hexane. Hexane (0.5?mL) was used as rinsing solvent, and PAHs were quantitatively eluted (80–97%) using 2?mL of hexane–dichloromethane (65–35) as eluting solvent. In these conditions, even the heaviest PAHs were quantitatively eluted. The optimized SPE method provides a short time and low-solvent-consumption sample clean-up compared with other conventional methods based on column chromatography. The analytical procedure, dynamic sonication-assisted extraction, followed by the optimized solid-phase extraction clean-up, was used to determine the 16 EPA priority PAHs from native lichens collected from the Aragon valley in central Pyrenees. The PAH concentrations in lichen samples ranged from 352 to 1654?ng?g^?1, and the minimum concentration value was established as the regional reference PAH levels in the area.     

Ab Initio Study of Structures,Metallotropic 1,2-Shifts and Prototropic 1,2-Shifts of Cyclopentadienyl(trimethyl)silane, -germane and -stannane

Molecular structures, metallotropic and prototropic shifts of cyclopentadienyl(trimethyl)silane ( 1 ), cyclopentadienyl(trimethyl)germane ( 2 ), and cyclopentadienyl(trimethyl)stannane ( 3 ) were investigated using ab initio molecular orbital and the Becke, Lee, Yang, and Parr density functional (B3LYP) methods. The results show that the most stable structure of compounds 1-3 has the (CH 3 ) 3 M fragment in the allylic position. The energy barrier of metallotropic shifts in compound 1 is higher than in 2 , and in compound 2 higher than in 3 , in good agreement with experimental data. The cyclopentadienyl rings in compounds 1-3 are found to be planar but this result contradicts the reported experimental data.     

Amperometric Hydrogen Peroxide Biosensor Based on Multiwall Carbon Nanotubes and Cadmium Sulfide Quantum Dots

<正>A novel third-generation hydrogen peroxide(H_2O_2) biosensor(Hb/CdS/MWNTs/GCE) was fabricated through hemoglobin(Hb) adsorbed onto the mercaptoacetic acid modified CdS QDs/carboxyl multiwall carbon nanotubes'(MWNTs) films.Cyclic voltammogram of Hb/CdS/MWNTs/GCE showed a pair of well-defined and quasi-reversible redox peaks with a formal potential(E~0) of-0.230 V(vs.Ag/AgCl) in 0.1 mol/L pH=8.0 phosphate buffer solution(PBS),which was the characteristic of the Hb heme Fe(Ⅲ)/Fe(Ⅱ) redox couple.The biosensor shows an excellent electrocatalytic activity to the reduction of H_2O_2.The response time of the designed biosensor to H_2O_2 at a potential of -0.30 V was less than 2 s and linear relationships were obtained in the concentration ranges of 2.0×10~(-6)—2.7×10~(-3) mol/L and 2.7×10~(-3)—7.7×10~(-3) mol/L with a detection limit of 3.0×10~(-7)mol/L(S/N=3).The apparent Michaelis-Menten constant K_m was estimated to be 1.324 mmol/L that illustrated the excellent biological activity of the fixed Hb.     

Musa sp. Leaves Extract Ameliorates the Hepato-Renal Toxicities Induced by Cadmium in Mice

Heavy metals intoxication causes several health problems that necessitate finding new protective and therapeutic approaches. This study aimed to evaluate the impact of Musa sp. leaves extract (MLE) on hepato-renal toxicities induced by cadmium (Cd) in male mice. The phytochemical screening, metal chelating activity (MCA), and the median lethal dose (LD₅₀) of MLE were determined. Fifty CD-1 male mice were used and intraperitoneally (i.p.) injected with MLE (1000 to 5000 mg/kg b.wt) for MLE LD₅₀ determination. Another 50 mice were used for evaluating the effect of MLE on Cd toxicity. Blood samples were collected for hematological, liver, and kidney functions assessments. Liver tissue homogenates were used for determination of oxidant/antioxidant parameters. Liver and kidney tissues were harvested for histopathological and molecular investigations. MLE showed potent in vitro antioxidant activities. The MCA and LD₅₀ of the MLE were 75 µg/mL and 3000 mg/kg b.wt, respectively. MLE showed beneficial therapeutic activity against hepato-renal toxicities in Cd-intoxicated mice, evidenced by improving the hematological, biochemical, histopathological, and molecular alterations.     

An overview of heterogeneous photocatalysis for the degradation of organic compounds: A special emphasis on photocorrosion and reusability

Heterogeneous photocatalysis has been extensively investigated for the degradation of organic pollutants from wastewater. The remarkable advantages of the heterogeneous photocatalysis process depend upon its ability to produce reactive oxygen species under visible/UV/solar light irradiation. However, the long-term stability and reuse potential of these catalysts are of great concern these days, yet understudied. This review aims to systematically present a state of the art understanding of such catalysts' reuse potential. Various important surface characteristics of the photocatalysts for improving the photostability and activity of the catalyst are discussed. Besides, the synergistic effect of different surface modified materials, composite materials and their surface characteristics for their enhanced activity are also covered. Finally, a discussion on various regeneration processes used for such catalysts is also presented, identifying some vital research needs in this field.     

Effect of the Ethanol/BTC Ratio on the Methane Uptake of Mechanochemically Synthesized MOF-199

We report on a detailed textural analysis of mechanochemically synthesized MOF-199 including N₂ adsorption-desorption and CO₂ adsorption isotherms data at 77 K and 273 K (up to atmospheric pressure), respectively, and CH₄ adsorption data at 298 K (up to 35 bar). We used the isotherm adsorption data to determine the micropore volume of the MOF-199 structures, to establish their methane uptake capacity and to understand how these properties depended on the Ethanol/BTC ratio used during the synthesis. The maximum methane uptake capacity for our specimens was recorded at 130 v/v at 35 bars. These results open an avenue for a better understanding of alternative manufacturing processes of MOF structures for gas storage applications.     

超球谐展开的收敛行为He原子的^3S态

利用相关函数－超球谐－广义Ｌａｇｕｅｒｒｅ函数方法，研究Ｈｅ原子＾３Ｓ态波函数向超球谐函数展开的收敛行为。截止于ｌ＝０，１，２的超球谐函数给出的本征能分别与组态相互作用的ｓ－，ｓｐ－，ｓｐｄ－极限能一致。仅用４４个超球谐函数，便得到了与精确的ＨｙｌｌｅｒａａｓＣＩ变分能量小数点后第５位的２＾３Ｓ，３＾３Ｓ的４＾３Ｓ态本征能吻合。     

(1R,2S)或(1S,2R)-1,2-二苯基-2-氨基乙醇衍生物手性配体的合成及其用于不对称催化反应

重点报道了以（１Ｒ，２Ｓ）或（１Ｓ，２Ｒ）－１，２－二苯基－２－氨基乙醇衍生物手性配体的合成及其用于不对称催化反应的研究，如去氢氨基酸的氢化、醛的乙基锌加成、酮的还原、活泼亚甲基化合物的烷基化、醛的硅腈化和瑞福马斯基反应等．研究了手性配体的结构、底物和反应条件等对上述反应的对映选择性和催化活性的影响．     

Polymerization of Norbornene via an Iron-Based Complex/MAO Catalytic System

IntroductionOwing to the high thermal stability,low waterabsorption and excellent optical properties as wellas the utility in an elastomeric material forvibration and sound damping or in a soakingmaterial for oil spills[1— 4 ] ,the homopolymers andthe copolymers of norbornene have attracted aconsiderable attention.So far,a large number oftransition- metal compounds have been known tocatalyze the ring- opening olefin metathesispolymerization (ROMP) ,or the vinyl additionpolymerization (VAP) …