酯基型双子季铵盐的合成及其性能研究

本文设计合成了系列含有不同疏水尾链长度和间隔基长度的酯基型双子季铵盐QAS(n+m),n和m分别表示间隔基长度和疏水尾链长度。通过红外光谱(FT-IR)、核磁共振氢谱(;H-NMR)和质谱(MS)对产物结构进行了鉴定。并借助于电导率法和微量肉汤稀释法分别研究了其表面活性和抑菌活性。结果表明:增加疏水尾链和间隔基的长度可提高QAS(n+m)的表面活性;QAS(n+m)对革兰氏阳性菌(金黄色葡萄球菌)和革兰氏阴性菌(大肠杆菌)均表现出较强的抑菌活性,且对金黄色葡萄球菌的抑菌活性强于大肠杆菌。

酯基型聚氧乙烯醚复配体系的性能研究

对酯基型聚氧乙烯醚改性油脂乙氧基化物(SOE)、脂肪酸甲酯乙氧基化物(FMEE)与常用表面活性剂脂肪醇聚氧乙烯(9)醚(AEO_9)、十二烷基苯磺酸(LAS)、乙氧基化烷基硫酸钠(AES)复配体系的性能进行研究,考察凝胶相区、泡沫、水溶分散性等性能的变化,分析SOE、FMEE对AEO_9、LAS、AES性能的影响。结果表明,SOE、FMEE可明显缩小AEO_9、LAS、AES的凝胶相区,大幅降低阴离子表面活性剂LAS、AES的泡沫性能,但与AEO_9在一定范围内会产生协同作用,其起泡力和稳泡力均高于单一表面活性剂,SOE、FMEE能够促进AEO_9、LAS、AES在水中的溶解,且当FMEE与LAS的质量比大于6∶4时,体系的水溶分散性优于单一表面活性剂。

Use of Glucosyl 3,5-Dinitrobenzoate in Synthesis of Glucosides and Related Oligosaccharides

To investigate a new glycosylation method. Methods In the presence of TMSOTfas catalyst, 1-O-(3, 5-dinitrobenzoyl)-2, 3, 4, 6-tetra-O-benzyl-α-D-glucopyranose 1 reacted with aseries of carboxylic acid, phenols, alcohols and saccharides respectively to give the correspondingglycosylation products. The compounds were determined by ~1H NMR and ^(13)C NMR spectra. ResultsThe α-glu-co-pyranosides and related oligosaccharides were prepared in high yields. Conclusion The3, 5-dinitro-benzoyl group was found to be a good leaving group at the anomeric position andO-glucopyranosides and oligosaccharides were stereoselectively synthesized in good yield.

Kinetics of the decomposition of dimethylhexane-1,6-dicarbamate to1,6-hexamethylene diisocyanate

The kinetics of the decomposition of dimethylhexane-1,6-dicarbamate to 1,6-hexamethylene diisocyanate was studied. A consecutive reaction model was established and the reaction orders for the two steps were confirmed to be 1 and 1.3 by the integral test method and the numerical differential method, respectively. The activation energies of the two steps were （56.94 4±5.90） kJ·mol^-1 and （72.07±3.47） kJ·mol^-1 with the frequency factors exp（ 12.53±1.42） min^- 1 and （ 14.254±0.84） tool^-0.33. L^0.33·min^-1, respectively. Based on the kinetic model obtained, the progress of the reaction can be calculated under given conditions.

D-β-hydroxybutyrate inhibits microglial activation in a cell activation model in vitro

Microglial activation plays an important role in a panel of neurological disorders such as multiple sclerosis(MS) and Parkinson's disease(PD),and is a key target for developing therapeutic strategies for these diseases.Ketogenic diet (KD),which is able to inhibit microglial activation in substantia nigra pars compacta of mice,has been shown effective in a mouse model of PD,possibly through increasing D-β-hydroxybutyrate(D-β-HB),a major component of ketone bodies.To verify this,we developed an in vitro model of microglia activation with a microglia line,BV-2,and investigated how D-β-HB have an effect on the LPS-stimulated BV-2 cells.We found D-β-HB is able to recover the cell viability,and inhibit the production of inflammatory mediators and cytokines such as ROS,nitrite,IL-1β,TNF-α,and IL-6,which otherwise were increased in LPS-stimulated BV-2 cells.We conclude that the LPS induced BV-2 cells activation is a valid in vitro model of microglia activation.D-β-HB is able to suppress the activation of BV-2 cells, which might account for one of the possible reasons of KD therapy on the PD model.

Macro kinetics for synthesis of dimethyl carbonate from urea and methanol on Zn-containing catalyst

In a stainless steel autoclave,the synthesis kinetics of dimethyl carbonate(DMC) from urea and methanol was separately investigated without catalyst and with Zn-containing catalyst.Without catalyst,for the first reaction of DMC synthesis(the reaction of urea with methanol to methyl carbamate(MC)),the reaction kinetics can be described as the first order with respect to the concentrations of both methanol and urea.For the second reaction of DMC synthesis(the reaction of MC with methanol to DMC),the results exhibit characteristics of zero-order reaction.For Zn-containing catalyst,the first reaction is neglected in the kinetics model since its rate is much faster than the second reaction.The macro-kinetic parameters of the second reaction are obtained by fitting the experimental data to a pseudo-homogenous model,in which a side reaction in forming process of DMC is incorporated since it decreases the yield of DMC drastically at high temperature.The activation energy of the reaction from MC to DMC is 104 kJ/mol while that of the side reaction of DMC is 135 kJ/mol.The highest yield of DMC is 23%.

A possible hydrolysis mechanism of β-naphthyl acetate catalyzed by antibodies

The mechanism of ester hydrolysis has been extensively studied; however, the precise function of active-site residues in promoting catalysis is nuclear. We describe here the structural models for the complex of a catalytic sntibody Fv fragment with a phosphonate transition -state analogue, constructed by using gene cloning, sequencing and molecular modeling, mainly based on a known X-ray structure of a catalytic atibody. Hydrophobic and electrostatic analyses of the Fv/analog and Fv/substrate interaction suggest the hydrolysis mechanism: In L91 and Tyr H97 play important roles to stabilize the β-naphthyl group of hapten through r-stack; His H35 donates a pair of free electrons at the atom NEZ to an active water and let it to be a partial hydroxide, which attacks the carbon atom of the carbonyl group of the substrate. Both His H35 and Arg L96 can form hydrogen bonds and stabilize the Anoinc tetrahedral intermediate formed during turnover. This mechanism emphasizes that an active water bridge may be formed during hydrolysis process.

Measurement and correlation of solubility of trimethylolethane in different pure solvents and binary mixtures

The solubilities of trimethylolethane in butanol,methyl acetate,ethyl acetate as well as in mixed solvents of(methanol+ethyl acetate) and(ethanol+ethyl acetate) were measured with the gravimetric method in the temperature range from 283.15 K to 318.15 K under atmosphere pressure.The experiment results showed that the solubility of trimethylolethane increased with the temperature,or along with the concentration of methanol or ethanol in the solvents of(methanol+ethyl acetate) and(ethanol + ethyl acetate).In addition,the experiment values were correlated by the van't Hoff equation,Modi fied Apelblat Equation,λh Equation,CNIBS/R-K equation and Jouyban–Acree Model.The Modi fied Apelblat Equation provided the best fitting results of the solubility data of TME in the pure solvents while the CNIBS/R-K model showed the best estimation of the solubility in the binary solvent mixtures.Furthermore,the density functional theory(DFT) calculations showed that solubility in different solvents related to the strength of the interaction between the trimethylolethane and the solvent molecules.Finally,the standard molar enthalpy and molar entropy of trimethylolethane during the dissolving process was also calculated by Modi fied Apelblat equation in this work.

A Structure-properties Study of MDI-based Hydrophilic Polyether-polyester Polyurethane

A series of segmented polyether-polyester polyurethane with amorphous hydrophilic soft segment domains were prepared from 4,4'- diphenylmethane diisocyanate (MDI), polybutylene adipate (Glycol) 2000 (PBA2000), and polyethylene glycol 1000 (PEG1000), with 1,4-butanediol (BDO) as the chain extender. Furthermore, several representative properties of the polyurethanes, such as moisture permeability, water resistance, hydrophilic property, and phase inversion temperature, were investigated. The studies show that the structure and concentration of soft segment have a remarkable effect on the main application properties of polyurethane. On the contrary, the functional properties of the polyurethane are almost not affected by its hard segment.

A novel method for fabricating polydimethylsiloxane microfluidic chip master molds

We proposed a novel method of fabricating polydimethylsiloxane (PDMS) microfluidic chip polymer master molds in this paper. The method mainly includes two steps. First, a stainless steel slice was laser etched to form a metal model. Then, the organic solution of poly(methyl methacrylate) (PMMA) was casted onto the metal model to fabricate the PMMA master which subsequently would be used to fabricate PDMS chips. We systematically researched different laser parameters influencing the surface status of microchannels and obtained optimized etching parameters. We investigated and optimized the organic solution composition of PMMA while casting chip masters, and developed a method to form fine polymer masters using two different viscosity solutions to cast the model in turn, and studied the repeatable replication. Then, we investigated physical performance of this chip and evaluated the practicability by analyzing Rhodamine B. Compared with present methods, the proposed method does not need photolithography on photoresistant and chemical etching. The entire fabricating progress is simple, fast, low-cost and can be controlled easily. Only several minutes are required to make a metal model, 3 hours for a PMMA master, and one day for PDMS chips.

Flexible organic-inorganic hybrid photodetectors with n-type phenyl-C61-butyric acid methyl ester （PCBM） and p-type pearl-like GaP nanowires

Flexible photodetectors have become a focus of current researches because they may offer some unique applications in various new areas that require flexible, lightweight, and mechanical shock-resistive sensing elements. In this work, we designed flexible organic-inorganic hybrid photodetectors on various flexible substrates, including polyethylene terephthalate （PET）, common Sellotape and polydimethylsiloxane （PDMS）, with n-type phenyl-C61-butyric acid methyl ester （PCBM） and p-type pearl-like GaP nanowires （NWs） as the active materials. The as-fabricated hybrid devices exhibited an optimized performance superior to the device made of pristine GaP NWs, with a fast response time （43 ms） and high on/off ratio （-170）. Under different bending conditions, the flexible hybrid photodetectors demonstrated excellent flexibility and electrical stability, which make them very promising for further large-scale, high sensitivity and high speed photodetector applications.

Asm8, a specific LAL-type activator of 3-amino-5-hydroxy-benzoate biosynthesis in ansamitocin production

The highly potent antitumor agent ansamitocin P3 is a macrolactam isolated from Actinosynnema pretiosum ATCC 31565. A 120-kb DNA fragment was previously identified as the ansamitocin biosynthetic gene cluster, and contains genes for polyketide assembly, precursor synthesis, post-polyketide synthesis modification, and regulation. Within the biosynthetic gene cluster, asm8 encodes an 1117-amino-acid protein with a high degree of similarity to the large ATP-binding LuxR family-type regulators. In the current study, we determined that inactivation of asm8 by gene replacement in ATCC 31565 resulted in the complete loss of ansamitocin production, and that complementation with a cloned asm8 gene restored ansamitocin biosynthesis. Interestingly, the disruption of asm8 decreased the transcription of genes responsible for 3-amino-5-hydroxybenzoate (AHBA) formation, the starter unit required for ansamitocin biosynthesis. Subsequently, feeding of exogenous AHBA to the asm8 mutant restored ansamitocin biosynthesis, which showed that Asm8 is a specific positive regulator in AHBA biosynthesis. In addition, investigation of asm8 homologs identified two new ansamitocin producers, and inactivation of the asm8 homolog in A. pretiosum ATCC 31280 abolished ansamitocin production in this strain. Characterization of the positive regulator Asm8 and discovery of the two new ansamitocin producers paves the way for further improving production of this important antitumor agent.

Heat Transfer in Internal Channel of a Blade:Effects of Rotation in a Trailing Edge Cooling System

The aerothermal performance of a trailing edge （TE） internal cooling system of a high pressure gas turbine blade was evaluated under stationary and rotating conditions. The investigated geometry consists of a 30：1 scaled model reproducing a typical wedge shaped discharge duct with one row of enlarged pedestals. The airflow pattern inside the device simulates a highly loaded rotor blade cooling scheme with a 90 [deg] turning flow from the radial hub inlet to the tangential TE outlet. Two different tip configurations were tested, the first one with a completely closed section, the second one with a 5 holes outlet surfaces discharging at ambient pressure. In order to assess rotation effects, a rotating test rig, composed of a rotating ann holding both the PMMA TE model and the instru mentation, was purposely developed and manufactured. A thin Inconel heating foil and wide band Thermochromic Liquid Crystals are used to perform steady state heat transfer measurements on the blade pres sure side. A rotary joint ensures the pneumatic connection between the blower and the rotating apparatus; more over several slip rings are used for both instrumentation power supply and thermocouple connection. A parallel CFD analysis involving steadystate RANS modeling was conducted to allow an insight of the flow field inside the redirecting channel and the interpedestal ducts to better interpret the developing vortical structures. LowReynolds grid clustering permits to integrate up to the wall both the momentum and the thermal boundary layer. Calculations were performed by means of an inhouse developed pressure based solver exploiting the kco SST turbulence model implemented in the framework of the opensource finite volume discretization toolbox OpenFOAM~. Analyzed flow conditions correspond to Reynolds number of 20000 in the hub inlet section and angular speed varies to obtain rotation numbers in the range from 0 to 0.3. The orientation of the rotation axis is orthogonal to the heated surface as to resemble a 90 [deg] blade metal angle. Results are reported in terms of de tailed heat transfer coefficient 2D maps on the suction side surface as well as spanwise profiles inside the pedestal ducts.