The application of the Lattice Boltzmann method to the one-dimensional modeling of pulse waves in elastic vessels

The one-dimensional nonlinear equations for the blood flow motion in distensible vessels are considered using the kinetic approach. It is shown that the Lattice Boltzmann (LB) model for non-ideal gas is asymptotically equivalent to the blood flow equations for compliant vessels at the limit of low Knudsen numbers. The equations of state for non-ideal gas are transformed to the pressure-luminal area response. This property allows to model arbitrary pressure-luminal area relations. Several test problems are considered: the propagation of a sole nonlinear wave in an elastic vessel, the propagation of a pulse wave in a vessel with varying mechanical properties (artery stiffening) and in an artery bifurcation, in the last problem Resistor–Capacitor–Resistor (RCR) boundary conditions are considered. The comparison with the previous results shows a good precision.     

Bioactive constituents of Iris hybrida (Iridaceae): Processing effect

Iris genus plants are a valuable source of bioactive compounds, which are an important component for pharmaceutical development. The present article shows the potential for mineral nutrition with application of magnesium sulfate, iron chelates and potassium oxide affecting the phenolic compound contents in Iris hybrida ‘Tsikavynka’, I. hybrida ‘Tambo’ and I. hybridа ‘Widecombe Fire’. The effect of mineral processing was specific to plant organs and varied in the component composition. The Iris rhizomes had an increased total phenolic compound content after treatment (up to 10% of the total isoflavonoid content, up to 8% of phenolic acids, up to 5% of γ-pyrones and up to 13% of flavonoids), determined using UV–vis spectroscopy. A positive effect of nutrition on the biosynthesis and content of individual isoflavonoids (tectoridin, nigricin d -glucoside, genistin, iristectorigenin B, nigricin, irigenin and irisolidone) and xanthone mangiferin in Iris rhizomes by HPLC was established. In addition, an increase in the chlorogenic acid amount in Iris leaves was noted. The results demonstrate the sensitivity of Iris phenylpropanoid metabolism to mineral nutrition and can be used to predict medical plant cultivation with increased content of bioactive constituents.     

A Dynamic Kinetic Resolution Approach to Axially Chiral Diaryl Ethers by Catalytic Atroposelective Transfer Hydrogenation

Diaryl ethers are widespread in biologically active compounds, ligands and catalysts. It is known that the diaryl ether skeleton may exhibit atropisomerism when both aryl rings are unsymmetrically substituted with bulky groups. Despite recent advances, only very few catalytic asymmetric methods have been developed to construct such axially chiral compounds. We describe herein a dynamic kinetic resolution approach to axially chiral diaryl ethers via a Brønsted acid catalyzed atroposelective transfer hydrogenation (ATH) reaction of dicarbaldehydes with anilines. The desired diaryl ethers could be obtained in moderate to good chemical yields (up to 79 %) and high enantioselectivities (up to 95 % ee) under standard reaction conditions. Such structural motifs are interesting precursors for further transformations and may have potential applications in the synthesis of chiral ligands or catalysts.     

Palladium-Catalyzed Atroposelective Kinetic C−H Olefination and Allylation for the Synthesis of C−B Axial Chirality

The direct C−H functionalization of 1,2-benzazaborines, especially asymmetric version, remains a great challenge. Here we report a palladium-catalyzed enantioselective C−H olefination and allylation reactions of 1,2-benzazaborines. This asymmetric approach is a kinetic resolution (KR), providing various C−B axially chiral 2-aryl-1,2-benzazaborines and 3-substituted 2-aryl-1,2-benzazaborines in generally high yields with excellent enantioselectivities (selectivity (S) factor up to 354). The synthetic potential of this reaction is showcased by late-stage modification of complex molecules, scale-up reaction, and applications.     

Effect of Direct yellow 50 removal from an aqueous solution using nano bentonite; adsorption isotherm,kinetic analysis and also thermodynamic behavior

The developing countries are suffering from the toxicity of different industrial effluents, especially dyes that contaminate water systems. This study successfully explained the preparation and characterization of nano bentonite to extract Direct Yellow Fifty (DY50). Direct Yellow 50 is an organic contaminant that may affect the quality of water. The characterization of prepared nanoparticles was done using Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR). The impact of different operating conditions was studied using different pH, dose, temperature, contact time, and initial DY50 concentrations. The obtained results indicated that nano bentonite could adsorb about 94 % at initial concentrations of 40 mg/L, respectively. The optimum removal conditions were observed at an acidic pH (pH 3) using a sorbent material dosage of 0.05 g for 4 h at 30 °C. The adsorption isotherm, kinetic analysis, and thermodynamic behavior were studied using linear equation form, and the adjusted R² was compared to detect the preferred models. The adsorption behavior pseudo-second order kinetics, and fitted Langmuir isotherm model, respectively, showed the chemisorption interactions between adsorbed and sorbed molecules. Thermodynamic behavior indicated that the reaction was exothermic. Finally, this study strongly recommended using nano bentonite for DY50 removal from an aqueous solution.     

双波长双指示剂催化动力学光度法测定痕量Fe(Ⅲ)

研究了在HCl介质中,Fe(Ⅲ)催化H2O2氧化甲基橙和亚甲基蓝褪色的指示反应。通过测量510nm和660nm波长处催化和非催化体系吸光度的变化,基于Fe(Ⅲ)的浓度与两波长处吸光度差值的加和呈线性关系,建立了双波长双指示剂催化动力学光度法测定Fe(Ⅲ)含量的新方法。方法的线性范围为0.008~0.24μg/mL,用该法测定菠菜、紫菜、蛋黄中Fe(Ⅲ)含量,相对标准偏差为1.0%~4.6%,加标回收率为98.9%~104.6%。     

邻菲啰啉-Fe(Ⅱ)分光光度法测定头孢唑啉钠

建立了用邻菲啰啉-Fe(Ⅱ)分光光度法测定头孢唑啉钠的方法 .头孢唑啉钠在0.10mol·L-1 NaOH溶液中,100℃水浴加热降解为含巯基的化合物.巯基化合物把Fe3+还原为Fe2+.加入邻菲啰啉显色,通过测定生成的橘红色配位化合物的吸光度间接测定头孢唑啉钠的含量.头孢唑啉钠浓度在0.02~40mg·L-1范围内呈现良好线性关系,线性回归方程A=0.043c(mg·L-1)-0.001,相关系数R=0.998 8,表观摩尔吸光系数ε=2.05×104 L·(mol·cm)-1,相对标准偏差RSD=1.27%,检测限(3σ/k)0.065mg·L-1.在此基础上,测定了市售头孢唑啉钠粉针剂的含量,回收率在99.17%~101.2%之间,结果令人满意.     

甲基绿分光光度法测定高氯废水中的铊

在0.08 mol/L氢溴酸介质中,Tl Br4–和甲基绿形成稳定的蓝紫色缔合物,该缔合物被乙酸异戊脂萃取后用分光光度法测定高氯废水中的铊。在最佳吸收波长590 nm处,铊的质量浓度在0~5μg/(10 mL)范围内与吸光度呈良好的线性关系,相关系数为0.998 7,检出限为0.005 3μg/mL。测定结果的相对标准偏差为1.99%~3.38%(n=6),样品加标回收率为96.55%~98.04%。该方法操作简单,可应用于高氯废水中铊的测定。     

Ti/α-PbO2/β-PbO2电极电化学降解2-氯酚

采用电化学沉积法在Ti基底上制备了复合电极Ti/α-PbO2/β-PbO2,扫描电镜结果表明电极呈现由β-PbO2小晶体组成的菜花状微观形貌.所制电极在电化学降解环境污染物2-氯酚时表现出较高的电催化效率、较好的电极稳定性和较长的电极寿命.用正交实验优化了电化学降解2-氯酚的实验条件.在最优的实验条件(2-氯酚初始浓度50 mg/L,电解质0.1 mol/L Na2SO4,温度35oC,阳极电流密度20 mA/cm2)下电化学降解180 min后,2-氯酚的去除率达100%.动力学结果表明, Ti/α-PbO2/β-PbO2电极上2-氯酚的电化学氧化符合准一级动力学过程.     

Liquid–liquid microextraction and spectrophotometric determination of anionic surfactants using Astra Phloxine FF

A novel and simple procedure for determination of anionic surfactants has been developed. The method is based on the reaction of sodium dodecyl sulphate (SDS) with Astra Phloxine FF reagent at pH 3–8, followed by liquid–liquid microextraction of the formed ion associate into an organic phase containing a mixture of carbon tetrachloride and dichloroethane (4:1, v/v) and subsequent UV-Vis detection at 555 nm. The calibration plot was linear in the range 0.006–0.29 mg L^?1 of SDS. The limit of detection (LOD), calculated based on 3s, is 0.002 mg L^?1. The method was applied to the determination of anionic surfactants in real wastewater samples.