Correlation between Boron Isotope of Coral Acropora and pH Value of Seawater Surface

A water circulation system with the almost same element composition and socket type was adopted in coral Acropora culture under different seawater pH value conditions and the data of the relationship between boron isotopic compositions of coral and seawater pH value by thermoelectric ionization mass spectrometer were obtained. According to the correlations between α_carb-3 of coral and the pH value of cultured seawater, α_carb-3 was not a constant but related to pH value, indicating that B(OH)₃ also incorporated carbonate. Therefore, the theoretical formula could not be used to calculate the seawater pH value from the δ¹¹B_carb value of the measured marine biological carbonate. The empirical equations obtained experimentally would be an alternative method to calculate the seawater pH value. In addition, the mixed precipitation of CaCO₃ and Mg(OH)₂ was found in aquaculture tanks with high pH value, and the δ¹¹B of the solid was significantly higher than that of cultured seawater. The result indicated that the presence of Mg(OH)₂ had a significant effect on the boron isotope fractionation, which deserved our attention.     

B(X)上保持约当积的固定点的满射

设B(X)是维数大于等于3的复Banach空间X上有界线性算子全体构成的代数.设A∈B(X),若Ax=x,则称x∈X是算子A的固定点.Fix(A)表示A的所有固定点的集合.本文刻画了B(X)上保持算子的Jordan积的固定点的满射.     

Leucine-coated cobalt ferrite nanoparticles: Synthesis,characterization and potential biomedical applications for drug delivery

This work was primarily focused on the synthesis, characterization and biomedical applications of cobalt ferrite (CoFe₂O₄) nanoparticles, which were synthesized by a facile solvothermal method using an amino acid of Leucine (Leu) as the surface coating agents. The morphology, structure and properties of the as-synthesized uncoated and Leu-coated CoFe₂O₄ nanoparticles were characterized in detail by means of XRD, SEM, TEM, DLS, FTIR, XPS, TGA and SQUID. More importantly, it was found that the Leu-coated CoFe₂O₄ nanoparticles can be used as the efficient drug delivery with a drug loading capacity of 0.32 mg/mg for doxorubicin hydrochloride (DOX), and the loaded DOX demonstrated a sustained and progressive release manner. The in vitro cytotoxicity studies towards the HeLa cells were carried out, and the results indicated that the Leu-coated CoFe₂O₄ nanoparticles exhibited a relatively high cell viability compared with that of bare CoFe₂O₄ nanoparticles and the DOX loaded Leu-coated CoFe₂O₄ nanoparticles presented an obvious cytotoxic effect on HeLa cells.     

直觉模糊模型检测在工程决策上的应用

将直觉模糊Kripke结构扩展到加权直觉模糊Kripke结构,将直觉模糊计算树逻辑诱导到加权直觉模糊计算树逻辑;研究在此之上的直觉模糊期望测度和多属性工程决策问题。用加权直觉模糊Kripke结构的权值自然地刻画了工程问题中的成本和收益,直觉模糊测度量化工程进展的不确定性,用加权直觉模糊计算树逻辑描述不确定性工程属性约束。给出了基于直觉模糊模型检测的多属性工程寻优算法,并讨论了算法的复杂度。     

基于残差加权经验过程方法的自回归模型分布变点监测

Change monitoring of distribution in time series models is an important issue.This paper proposes a procedure for monitoring changes in the error distribution of autoregressive time series,which is based on a weighed empirical process of residuals with weights equal to the regressors.The asymptotic properties of our monitoring statistic are derived under the null hypothesis of no change in distribution.The finite sample properties are investigated by a simulation.As it turns out,the procedure is not only able to detect distributional changes but also changes in the regression coefficient and mean.Finally,we apply the statistic to a groups of financial data.     

A pre-enrichment procedure using diethyldithiocarbamate-modified TiO2 nanoparticles for the analysis of biological and natural water samples by ICP-AES

In this article, a new method that utilizes a diethyldithiocarbamate-modified nanometre TiO₂ (TiO₂–DDTC) as solid-phase extractant has been developed for simultaneous preconcentration of trace Cu(II), Pb(II), Zn(II), and Cd(II) prior to measurement by inductively coupled plasma atomic emission spectrometry (ICP-AES). The separation/preconcentration conditions of analytes, which include the effects of pH, sample flow rate and volume, elution conditions, and interfering ions on the recovery of the analytes, were investigated. At pH 5, the adsorption capacity of modified nanometre TiO₂–DDTC was found to be 6.2, 19, 4.7, and 6.0?mg/g for Cu(II), Pb(II), Zn(II), and Cd(II), respectively. According to the definition of IUPAC, the detection limits (3σ) of this method for Cu(II), Pb(II), Zn(II), and Cd(II) were 0.41, 1.7, 0.39, and 0.52?ng/mL, respectively. The proposed method achieved satisfied results when applied to the determinations of trace Cu(II), Pb(II), Zn(II), and Cd(II) in biological and natural water samples.     

Highly selective determination of rhodium(III) using silica gel surface-imprinted solid-phase extraction

A novel Rh(III)-imprinted amino-functionalised silica gel sorbent was prepared by a surface imprinting technique for preconcentration and separation of Rh(III) prior to its determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Compared with the traditional solid sorbents and non-imprinted polymer particles, the ion-imprinted polymers (IIPs) had higher adsorption capacity and selectivity for Rh(III). The maximum static adsorption capacity of the imprinted and non-imprinted sorbent for Rh(III) was 29.86?mg?g^?1 and 11.23?mg?g^?1, respectively. The imprinted Rh(III) was removed with 2?mL of 3% thiourea?+?2?mol?L^?1 HCl. The obtained imprinted particles exhibited excellent selectivity and rapid kinetics process for Rh(III). The relatively selective factor (α_r) values of Rh(III)/Ru(III), Rh(III)/Au(III), Rh(III)/Pt(IV), Rh(III)/Ir(IV), Rh(III)/Pd(II) were 26.7, 39.0 29.2, 28.1, 43.7, respectively, which were greater than 1. The detection limit (3σ) of the method was 0.26?µg?L^?1. The relative standard deviation of the method was 1.79% for eight replicate determination of 10?µg of Rh³⁺ in 200?mL water sample. The method was validated by analysing standard reference material (GBW 07293), the results obtained is in good agreement with standard values. The developed method was also successfully applied to the determination of trace rhodium(III) in geological samples with satisfactory results.     

Recent advances in the application of sulfinic acids for the construction of sulfur-containing compounds

Sulfur-containing organic compounds display wide applications in the field of materials science, synthetic chemistry, and pharmaceutical industry. Thus, numerous synthetic strategies have been developed for the synthesis of sulfur-containing compounds in synthetic chemistry. In recent years, the utilization of sulfinic acids as versatile synthons has emerged as attractive and powerful approach to access various organosulfur compounds through sulfonylation, sulfinylation or sulfenylation reaction...     

Hyperterpenoids A and B: Two pairs of unprecedented 6/6/4/6/6 polycyclic cyclobutane meroterpenoids with potent neuroprotective and anti-inflammatory activities from Hypericum beanii

Hyperterpenoid A (1) and B (2), two pairs of enantiomers, with an unprecedented 6/6/4/6/6 polycyclic skeleton, along with one known compoud hypermonone A (3) were isolated from Hypericum beanii. The racemate (±)-1 and (±)-2 were successfully separated into the two optically pure enantiomers (ee ≥ 99%) using a preparative HPLC system. Their absolute configurations were elucidated by extensive spectroscopic analyses and single-crystal X-ray diffraction method. The related plausible biogenetic pathways were presented. Compound 1-3 showed significant neuroprotective activity and potential anti-inflammatory activity. The result that (+)-2 and (-)-2 presented different anti-inflammatory properties, may lead us to new discovery of structure activity relationship between racemates, enantiomers, and diastereomers, as well as further research regarding the binding of drugs to target proteins.