Preparation of weak cation exchange packings based on monodisperse poly(glycidyl methacrylate-<Emphasis Type="Italic">co</Emphasis>-ethylene dimethacrylate) beads and their chromatographic properties

The monodisperse, macroporous poly(glycidyl methacrylate- co-ethylene dimethacrylate) beads were synthesized by a single-step swelling and polymerization method. Based on this media, a weak cation exchange (WCX) stationary phase for HPLC was synthesized by a new chemically modified method. The prepared resin has advantages for biopolymer separation, high column efficiency, low column backpressure, high protein mass recovery, and good resolution for proteins. The measured bioactivity recovery for lysozyme was 98+/-5%. The dynamic protein loading capacity of the WCX packings was 17.3 mg g(-1). The experimental results show that the synthesized WCX resin has very weak hydrophobicity.     

政府奖惩机制下零售商主导的闭环供应链微分博弈策略

本文在考虑政府奖惩机制下,研究零售商主导的闭环供应链中成员的动态均衡策略,其中制造商负责回收再制造,回收率随时间动态变化。分别构建了三种模式下的Stackelberg微分博弈模型:政府不对制造商和零售商实施奖惩机制、政府只对制造商实施奖惩机制以及政府同时对制造商和零售商实施奖惩机制。运用贝尔曼连续型动态规划理论,求解了三种模式下制造商和零售商的决策均衡结果并进行了对比分析,从消费者剩余价值和成员利润的视角证明了政府实施奖惩机制的有效性。最后通过算例对成员均衡策略进行了稳态分析和非稳态分析。研究结果表明:政府的奖惩机制能够正确引导闭环供应链成员做出最优决策,有利于减缓分散决策所带来的双重边际效应,提高消费者剩余价值。零售商分担回收责任会削减政府对制造商回收的激励作用,降低闭环供应链整体利润。相比之下,政府只对制造商实施奖惩机制是最优模式选择,可以同时提高经济和环保双重效益。     

Inclusion complexes of alcohols with α-cyclodextrin

Calorimetric studies of the inclusion complexes of straight and branched alcohols and of diols with alpha-cyclodextrin (-CD) have been carried out in water solvent. The data suggest that straight and branched chain alcohols enter the cavity of -CD alkyl end first. The hydroxyl group hydrogen bonds to the outer oxygen ring of the cyclodextrin. For branched chain alcohols the longer alkyl part of the molecule penetrates the -CD cavity up to the hydroxyl group. Diols form two hydrogen bonds to the outer oxygen ring of the cyclodextrin with some penetration into its interior.     

Generalized evaluation subgroups of product spaces relative to a factor

For any -complexes and , we show that . We use this fact to compute generalized evaluation subgroups of generalized tori relative to a sphere.

     

New hydrolysis method for extremely small amount of lipids and capillary gas chromatographic analysis as n(O)-tert.-butyldimethylsilyl fatty acid derivatives compared with methyl ester derivatives

The organic basic solution, 1 M tetramethylammonium hydroxide (TMAH) in methanol, was employed for the hydrolysis of extremely small amounts of lipids compared to the classical inorganic basic solution, 1 M KOH in ethanol. The hydrolysed fatty acids were derivatized as N(O)-tert.-butyldimethylsilyl (tBDMSi) esters with N-methyl-N-(tert.-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) and compared with the classical derivatives, the methyl esters, made by the BF3-methanol method. Recoveries of fatty acids determined on the standard fatty acids and soybean oil hydrolysed with TMAH were high: about 1.1-2.1- and 2.0-5.4-times, respectively, in all fatty acids compared with the hydrolysis by KOH regardless of derivatization method. The relative standard deviations (RSDs) on the recoveries of standard fatty acids were less than 5% when hydrolysed with TMAH, regardless of derivatives, but when hydrolysed with KOH, RSDs were more than 5% for most fatty acids, especially for long-chain fatty acids. The RSDs on the recoveries of fatty acids on the soybean oil were also very high in the KOH hydrolysis. Fatty acid compositions of soybean oil were similar in the main fatty acids regardless of hydrolysis methods, but showed slightly different values, depending on the methods of derivatization. RSDs were also very high in the KOH hydrolysis. In view of these results, precision of analysis by KOH hydrolysis was very poor, so we could not rely on the data. On the other hand, the reliability of data by TMAH hydrolysis method was very high, so it is a useful new hydrolysis method for extremely small amounts of lipid samples. Both derivatives of 35 standard fatty acids were successfully separated on a HP-1 nonpolar capillary column. tBDMSi derivatives were completely resolved in 70 min by 295 degrees C. In the methyl ester derivatives it took about 80 min to get satisfying resolution, but these derivatives were completely resolved by 250 degrees C. The sensitivity of tBDMSi derivatives was about 1.5-6.3-times higher than that with methyl ester derivatives. The stability of tBDMSi derivatives was constant for about 144 h except arachidic, docosahexanoic, behenic and heneicosanoic acids, which were stable for only 86 h.     

Gas chromatographic study of the urinary codeine-to-morphine ratios in controlled codeine consumption and in mass screening for opiate drugs

The urinary codeine-to-morphine ratios in fifteen volunteers administered codeine tablets at intervals were studied by gas chromatography (GC) and compared with one month's GC results for enzyme multiplied immunoassay technique (EMIT)-screened urine specimens in a mass-screening programme for abuse of opiate drugs, particularly heroin. It appears that when M less than 2 and C/M greater than 0 or when M greater than 2 and C/M greater than 0.5, where C and M are codeine and morphine concentrations in micrograms per 10 ml of urine, codeine consumption has to be presumed.     

A New Method to Investigate the Clustering Phenomena in Supercritical Fluids

EstimationoflocaldensityofsolventaboutthesoluteSolvatochromicbehaviorsofspectroscopicprobesarewidelyusedtoestimatethesol-ventstrengthofsupercriticalfluids(SCF,).i-3lnthiswork,thesolvatochrondcshiftofthen-n*transitionbandforacetone(O.o37mo1.L-')insupercrihcal(SC)CO2wasde-terminedbyUVspectroscopytostUdythesolvationeffect.TheMcRae-BaylissexpressionbasedonthedielectriccontinUUInmodelgivestherelahonshipbetWeenso1vatochromicshiftandpo1arizabilityofnonPolarsolvents4-5asfollows:wherevisthewave…     

Study of hydantoin. III . Mass spectrometric behaviour in the electron impact of 2-imino-4-thiazolidinone derivatives

The mass spectral decomposition modes of a series of 2-imino-4-thiazolidinone derivatives are reported and discussed. The fragmentation patterns and mechanisms postulated have been confirmed by the analysis of the MIKE spectra and using DADI technique and the effects of heteroatoms and substituents on the MIKE spectrum of these compounds are compared with that of 3-substituted hydantoins.     

π-Allyl palladium approach toward the diazabicyclo[3.2.1]octane core of the naphthyridinomycin alkaloids

A novel and efficient protocol for the synthesis of the 3,8-diazabicyclo[3.2.1]octane system found in the naphthyridinomycin, dnacin, and tetrazomine families of alkaloids is described. The key transformation involves an intramolecular palladium-catalyzed allylic alkylation. The cyclization proceeds smoothly under mild conditions (20 mol % Pd₂dba₃, 1.5 equiv DBU, 65 °C, THF, 20 min) to afford 3,8-diazabicyclo[3.2.1]octanes in excellent yields (94-98%).