Pharmacokinetics and tissue distribution study of clevidipine and its primary metabolite H152/81 in rats

This present study was designed to investigate the pharmacokinetic profiles and tissue distribution characteristics of clevidipine and its primary metabolite H152/81 in rats following a single intravenous administration of clevidipine butyrate injectable emulsion. For this study, a sensitive and selective liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was established and validated for the simultaneous quantitation of clevidipine and H152/81 in rat whole blood and various tissues. A Hedera ODS‐2 column with two gradient elution programs was employed for the troubleshooting of matrix effect on the detection of analytes among different biological samples. The experimental data showed that clevidipine represented quick elimination from blood with a half‐life of about 4.3 min and rapid distribution in all of the investigated tissues after administration; the highest concentration of clevidipine was found in the heart whereas the lowest concentration was detected in the liver. In addition, clevidipine was almost undetectable in most tissues except for heart and brain at 90 min post‐dosing, suggesting that there was no apparent long‐term accumulation in rat tissues. For H152/81, the peak concentration of 3714 ± 319 ng/mL occurred at 0.129 ± 0.048 h, the half‐life was 10.08 ± 1.45 h and area under the concentration–time curve was 42091 ± 3812 ng h/mL after drug administration. In addition, H152/81 was found at significant concentration levels in all tissues, in descending order of lung, kidney, heart, liver, spleen and brain at each time point. The results of current study offer useful clues for better understanding the distribution and metabolism of clevidipine butyrate injectable emulsion in vivo.     

Residual level of dimethachlon in rice‐paddy field system and cooked rice determined by gas chromatography with electron capture detector

In this study, a modified quick, easy, cheap, effective, rugged and safe method coupled with gas chromatography with electron capture detection was established to determine dimethachlon residues in paddy soil, rice husk, rice straw, brown rice and cooked rice. The limits of quantification of dimethachlon were 0.01 mg/kg for paddy soil, brown rice and cooked rice and 0.02 mg/kg for rice straw and rice husk. The mean recoveries were in the range 78.59–104.7% with relative standard deviation values of <10% for dimethachlon in the five matrices. For field experiments, the final residues of dimethachlon in paddy soil were < 0.05 mg/kg and were < 1.21 mg/kg in rice straw from six sites. The final residues of dimethachlon in the brown rice at 21, 28 and 35 days after spraying from six sites were 0.08–7.58 mg/kg, and 0.16–30.1 mg/kg in rice husk. Our six test sites covered the main rice–producing areas of China. The routine rice cooking process of a Chinese family could apparently increase the removal of dimethachlon in rice compared with brown rice, and the reduction ratios were > 96%.     

A non-Gaussian Ornstein–Uhlenbeck model for pricing wind power futures

The recent introduction of wind power futures written on the German wind power production index has brought with it new interesting challenges in terms of modelling and pricing. Some particularities of this product are the strong seasonal component embedded in the underlying, the fact that the wind index is bounded from both above and below and also that the futures are settled against a synthetically generated spot index. Here, we consider the non-Gaussian Ornstein–Uhlenbeck type processes proposed by Barndorff-Nielsen and Shephard in the context of modelling the wind power production index. We discuss the properties of the model and estimation of the model parameters. Further, the model allows for an analytical formula for pricing wind power futures. We provide an empirical study, where the model is calibrated to 37 years of German wind power production index that is synthetically generated assuming a constant level of installed capacity. Also, based on 1 year of observed prices for wind power futures with different delivery periods, we study the market price of risk. Generally, we find a negative risk premium whose magnitude decreases as the length of the delivery period increases. To further demonstrate the benefits of our proposed model, we address the pricing of European options written on wind power futures, which can be achieved through Fourier techniques.     

Boundedness properties in function spaces

Some boundedness properties of function spaces (considered as topo- logical groups) are studied.     

Well‐defined polyisoprene‐grafted silica nanoparticles via the RAFT process

The preparation of well‐defined polyisoprene‐grafted silica nanoparticles (PIP‐g‐SiO₂ NPs) was investigated. Surface initiated reversible addition fragmentation chain transfer (SI‐RAFT) polymerization was used to polymerize isoprene from the surface of 15 nm silica NPs. A high temperature stable trithiocarbonate RAFT agent was anchored onto the surface of particles with controllable graft densities. The polymerization of isoprene mediated by silica anchored RAFT with different densities were investigated and compared to the polymerization mediated by free RAFT agents. The effects of different temperatures, initiators, and monomer feed ratios on the kinetics of the SI‐RAFT polymerization were also investigated. Using this technique, block copolymers of polyisoprene and polystyrene on the surface of silica particles were also prepared. The well‐defined synthesized PIP‐g‐SiO₂ NPs were then mixed with a polyisoprene matrix which showed a good level of dispersion throughout the matrix. These tunable grafted particles have potential applications in the field of rubber nanocomposites. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1493–1501     

一步法制备含W介孔碳材料及其氧化脱硫性能研究

以钨酸钠为钨源,以乙二胺四乙酸二钠为碳源经过高温煅烧制备了含W的介孔碳材料,采用XRD、SEM、FT-IR、BET对含钨的介孔碳材料进行表征。结果表明,煅烧后介孔碳材料的表面形成了粒状含有结晶水的氧化钨(WO_3·H_2O)。相比于纯的介孔碳材料,含钨介孔碳材料的总比表面积减小。以含W介孔碳材料为催化剂,H_2O_2作为氧化剂,1-丁基-3-甲基咪唑氟硼酸盐([BMIM][BF_4])离子液体作为萃取剂,组成萃取-催化氧化脱硫体系(ECODS)并研究其对模拟油中二苯并噻吩脱除效果。考察了氧化钨负载量、反应温度、H_2O_2加入量、催化剂用量、离子液体用量以及不同类型硫化物对二苯并噻吩脱除的影响。在最佳反应条件下,催化剂对二苯并噻吩(DBT)、4,6-二甲基二苯并噻吩(4,6-DMDBT)、苯并噻吩(BT)、噻吩(TH)和真实汽油的脱除率分别达到98.6%、65.6%、61.2%、57.8%和64.3%。催化剂回收利用五次之后脱硫率略有降低,仍高达95.2%。     

A new procedure for determination of nickel in some fake jewelry and cosmetics samples after dispersive liquid–liquid microextraction by FAAS

A new, simple and cheap dispersive liquid–liquid microextraction (DLLME) procedure was optimized for the preconcentration of trace amounts of Ni(II) as a prior step to its determination by flame atomic absorption spectrometry (FAAS). It is based on the microextraction of nickel, where appropriate amounts of the extraction solvent (CHCl₃), disperser solvent (ethanol) and chelating agent, name 5‐[(Z)‐isoxazol‐3‐yl‐diazenyl]‐2‐methyl‐quinolin‐8‐ol (MMD), were firstly synthesized/characterized and used. Various parameters that affect the extraction procedure such as pH, centrifugation rate and time, the chelating agent (MMD) concentration and sampling volume on the recovery of Ni(II) were investigated. The preconcentration of a 20 ml sample solution was thus enhanced by a factor of 80. The resulting calibration graph was linear in the range of 0.24–10 mg L⁻¹ with a correlation coefficient of 0.9998. The limit of detection (3 s/b) obtained under optimal conditions was 1.00 μg L⁻¹. The relative standard deviation for certified reference material determinations was 1.2%. The accuracy of the method was verified by the determination of Ni(II) in the certified reference material of wastewater (Waste water CWW TMD). The proposed procedure was successfully applied to the determination of Ni(II) in some fake jewelry and cosmetics samples.     

Reactive ligand influence on initiation in phenylene catalyst‐transfer polymerization

Synthesizing conjugated polymers via catalyst‐transfer polymerization (CTP) has led to unprecedented control over polymer sequence and molecular weight. Yet many challenges remain, including broadening the monomer scope and narrowing the molecular weight dispersities. Broad polymer dispersities can arise from nonliving pathways as well as slow initiation. Previously, slow initiation was observed in Ni‐mediated CTP of phenylene monomers. Although precatalysts with faster initiation rates have been reported, the rates still do not exceed propagation. Herein a second‐ and third‐generation of reactive ligands are described, along with a simple method for measuring initiation rates. A precatalyst with an initiation rate that exceeds propagation is now reported, however, the resulting polymer samples still exhibit broad dispersities, suggesting that slow initiation is not the most significant contributing factor in Ni‐mediated phenylene polymerizations. In addition, initiation rates measured under authentic polymerization conditions revealed that both exogenous triphenylphosphine and an ortho‐trifluoroethoxy substituent on the reactive ligand have a strong influence. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1530–1535     

Impact of average photon-energy coefficient of solar spectrum on the short circuit current of photovoltaic modules

The output energy of photovoltaic (PV) modules is influenced by the spectral irradiance distribution of the solar spectrum under outdoor conditions. To rate the precise output energy of PV modules, the correction of short circuit current (I_SC) based on actual environmental conditions is needed, because I_SC significantly depends on the shape of the spectral irradiance distribution. The average photon energy (APE) is a zero-dimensional index for spectral irradiance distribution, and APE value uniquely describes the shape of a solar spectrum. Thus, APE has an impact on I_SC of PV modules. In this contribution, the relationship between APE coefficient and I_SC of the multi-crystalline silicon, single-crystalline silicon, heterojunction intrinsic thin-layer, back contact, copper indium selenide and cadmium telluride PV modules has explored. It is revealed that APE value changes the I_SC of PV modules which appeared to have immense possibilities of I_SC correction using APE coefficient. This new approach can be very effective for precise rating the output energy of PV modules under actual outdoor conditions.     

Mannose‐based graft polyesters with tunable binding affinity to concanavalin A

Glycopolymers have been widely used to understand the interactions between carbohydrates and lectins, which facilitate the diagnosis and detection of disease and pathogens as well as the development of vaccines. While studies have been focused on the correlation of glycopolymer structure and their binding to lectins, graft‐type glycopolyesters are uncommon. Herein, we report the design and synthesis of mannose‐based graft polyesters by “grafting‐from” method and investigate their interactions with Concanavalin A (Con A). As confirmed by ¹H NMR spectroscopy and sulfuric acid‐UV method, graft polyesters with different lengths of mannose graft were successfully synthesized. Our results from turbidimetry binding assay showed that graft polyesters with longer mannose graft exhibit higher initial binding rate (k_i). Isothermal titration calorimetry measurements of these graft polyesters with Con A showed that polymers exhibit higher binding affinity (k_a) with the number of side chain mannose. This study provides understanding of the interaction between Con A and mannose‐based graft polyesters, which can be employed for the development of glycopolymeric therapeutics. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3908–3917