GENETIC ENGINEERING OF TOBACCO PLANTS WITH CMV RESISTANCE CONFERRED BY MONOMER cDNA OF SATELLITE RNA

The synthesized full-length cDNA to CMV satellite RNA-1 was integrated into plant expression vector RoKII with a CaMV 35S promoter. Infected by Agrobacterium tumefaciens harbouring the recombinant plasmid. The tobacco leaf discs (the G-140 variety which is widely cultivated in China) were regenerated into plants. After being inoculated with virulent strain CMV, most of the transgenic plants expressed satellite RNA at high levels and developed a much milder symptom than the untransformed ones.Basically in accordance with Mendel's law of segregation, the novel tobacco pure line engineered with viral resistance was screened out. The secondary generation transgenic plants still maintained high level satellite RNA expression and the resistance to CMV.     

A NEW SPIROPLASMA FROM THE SURFACE OF PLANT FLOWER IN CHINA

The strain CCH, isolated from the surface of the plant flower in China, is a wall- less,helical prokaryote which passes through a microfilter 0. 22 μm in diameter. Cholesterol isrequired for its growth. The strain CCH could metabolize glucose, fructose, maltose, treha-lose and arginine, but not urea. Its electrophoresis pattern of cell proteins is distinct fromthat of other spiroplasmas. The guanine-plus-cyrosine content of its DNA determined bymelting temperature is 29. 15 mol%. No relation with any known spiroplasmas was found inenzyme-linked immunosorbent assay and deformation tests. According to these results, thestrain CCH is referred to a new species in the genus of Spiroplasma or the representative ofa new spiroplasma group.     

Experimental and Theoretical Study of the Effect of Moisture on Methane Adsorption and Desorption by Activated Carbon at 273.5 K

Adsorption and desorption of methane by activated carbon (AC) at constant temperature and at various pressures were investigated. The effect of moisture was also studied. A volumetric method was used, up to 40 bar, at a temperature of 273.5 K. Results of a dry AC sample were compared with those obtained from a moist sample and two different ACs with different physical and surface properties were used. As expected, the results showed that the existence of moisture, trapped in the AC pores, could lead to a decrease in the amount of methane adsorbed and a decrease in the amount of methane delivered during desorption. To model the experimental results, a large variety of adsorption isotherms were used. The regressed parameters for the adsorption isotherms were obtained using the experimental data generated in the present study. The accuracy of the results obtained from the different adsorption isotherms was favorably compared.     

Denatured Thermodynamics of Proteins in Weak Cation－exchange Chromatography

The thermostability of some proteins in weak cation-exchange chromatography was investigated at 20—80 ℃. The results show that there is a fixed thermal denaturation transition temperature for each protein. The appearance of the thermal transition temperature indicates that the conformations of the proteins are de-stroyed seriously. The thermal behavior of the proteins in weak cation-exchange and hydrophobic interaction chromatographies were compared in a wide temperature range. It was found that the proteins have a higher thermostability in a weak cation-exchange chromatography system. The thermodynamic parameters (△H^0,△S^0) of those proteins were determined by means of Van′t t Hoff re|ationship(lnk′-1/T). According to stan-dard entropy change(△S^0) , the conformational change of the proteins was judged in the chromatographic pro-cess. The linear relationships between △H^0 and △S^0 can be used to evaluate “compensation temperature“ (β) at the protein denaturation and identify the identity of the protein retention mechanism in weak cation-ex-change chromatography.     

CONFORMATIONAL ANALYSIS ON ANTICHOLINERGIC DRUG (Ⅰ) MOLECULAR MECHANICS MMPM CALCULATION OF ATROPINE AND OTHER ALKALOIDS IN THE BELLADONNA PLANT

Alkaloids of balladonna plant were studied by molecular mechanics MMPM calculation. The results showed that the ideal conformation was quite different from the structure found in the crystals of the alkaloids in belladonna plant. The intramolecular hydrogen bond was present between the hydroxy group and carbonyl oxygen atom in the ideal conformation for these alkaloids. The origin of asymmetrical molecules in nature obeys the lowest energy principle. This may be a reason why only S-(-) not R-(+)-isomer, only hyoscyamine not pseudotropine were found to be present in natural belladonna plant, The model of four recognition sites between anticholinergic drug-receptor interaction in mydriasis was suggested, in which the hydroxy group with 8～9 A distanced from nitrogen atom is possibly necessary for maximum mydriasis activity.     

STUDY ON THE ADSORPTION OF PHENOL BY CHITOSAN FROM AQUEOUS SOLUTION

The effects of pH, initial concentration and temperature on the adsorption of phenol by chitosan were investigated in this paper. The isothermal data was applied to Langmuir linear and the Freundlich linear isotherm equation, and the thermodynamic parameters （AH, AG, AS） were calculated according to the values of binding Langmuir constant, KL. Results indicated that the adsorption between chitosan and phenol was significantly physical in nature, the negative ΔH constant at lower temperature confirmed that more phenol was adsorbed by chitosan at lower temperature. The kinetics of the sorption process of phenol on chitosan was investigated using the pseudo-first order and pseudo-second order kinetics, and results showed that the second order equation model provided the best correlation with the experimental results.     

ON A DIFFERENTIAL EQUATION FOR KINETICS OF NON- ISOTHERMAL CRYSTALLIZATION

A new differential equation was derived from the modified first-order kinetic model to describe the polymer crystallization processes. The crystallization experiments were carried out by means of DSC. Poly (ethylene terephthalate) resins were selected as the samples containing different catalysts. The relationships between the parameters obtained from the known Avrami equation and from one in the present paper were discussed. A method for applying the equation to determine the kinetic parameters from a constant heating and a constant cooling curve was proposed.     

COMPONENT ANALYSIS OF SLOW-RUSTING RESISTANCE OF WHEAT CULTIVARS TO STRIPE RUST (Puccinia striiformis) (Ⅰ)

Under field conditions in 1984 and 1985, resistance components (infection frequency, sporulationcapacity, latent period, lesion size expansion and infectious period) were quantified on six wheat cultivarsinoculated with 3 races of Puccinia striiformis at three different growth stages. The five resistance com-ponents of slow-rusting cultivars were significantly different from those of the check cultivar, and thevariance among cultivars occupied the most part of total variance. The cultivar×race interactions eitherwere insignificant or only occupied a very small proportion of the total variance. Results of estimation ofthe resistance component parameters were fitted to the apparent infection rates of these cultivars in thefields.     

THE SYNTHESIS OF PHOSPHORAMIDOTHIOATES AND THEIR QUANTITATIVE STRUCTUREACTIVITY CORRELATIONS

O-Aryl O-ethyl N-isopropyl phosphoramidothioates (Ⅰ) have herbicidal activity. In order to study the relationship between structures and activities of these compounds, more than thirty compounds (Ⅰ) have been prepared by the reaction of O-aryl O-ethyl phosphorochloridothioates with isopropylamine in the presence of 40% NaOH at 0℃. The intermediates, phosphorochloridothioates, were prepared separately from a large excess of O-ethyl Phosphorodichloridothioate and various substituted phenols in the presence of 40% NaOH and a catalyrical amount of Et_3N at 0—5℃. As a result, higher purity and good yields were obtained.It was found that the activity of these compounds was highly dependent upon the substituents attached to the benzene ring with respect to the characteristic parameters π, E_s, σ and F by using Hansch's equation.It was indicated that hydrophobic (π), steric (E_s), and electronic (σ and F) effects of the substituents on the ring in those molecules seem to be of considerable importance i     

Kinetic and thermodynamic studies of the esterification of acidified oil catalyzed by sulfonated cation exchange resin

This study describes the kinetics and thermodynamics of the esterification of acidified oil with methanol catalyzed by sulfonated cation exchange resins(SCER). The effects of the mass ratio of methanol to acidified oil,reaction temperature,and catalyst loading were studied to optimize the conditions for maximum conversion of free fatty acids(FFAs). The results showed that the optimal conversion rate of FFAs was 91.87% at the mass ratio of methanol to acidified oil of 2.5:1.0,reaction temperature of 65.0 °C,catalyst loading of 5.0 g and reaction time of 8.0 h. The external and internal mass transfer resistances were negligible based on the experimental results and a pseudo-homogeneous kinetic model was proposed for the esterification. The activation energy and thermodynamic parameters including G,S and H were determined. The conversion rates of FFAs obtained from the established model were in good agreement with the experimental data.     

Effect of organic modifiers on the capacity factor in micellar electrokinetic chromatography

Organic modifiers were effective both to extend the migration time window and to improve the separation of very hydrophobic compounds in MEKC.An iteration method was used to determine the migration time of micelles.The quantitative relationship between the capacity factor k' and the concentration of organic modifiers was derived,which was investigated experimentally.The linear solvation energy relationships (LSER) methodology was applied to MEKC,and good linear relationships between Ink' and solvatochromic parameters of 15 solutes were obtained in the presence of organic modifier in different concentrations,which indicated a new access in MEKC to predict k' from the structural parameters of solutes.The effect of column temperature T on k' was also investigated.     

Proteomics Dissection of Cold Responsive Proteins Based on PEG Fractionation in Arabidopsis

Proteome profiling was performed on Arabidopsis plant exposed to cold stress at 4 ℃ for 24 h in an attempt to explore the mechanisms of plant climate adaptation.The polyethylene glycol（PEG） fractionation protocol developed in this lab was used to identify as many differentially expressed low-abundance proteins as possible.In comparison with those of the biological controls,67 protein spots with at least two-fold difference in expression were identified for the plant exposed to cold temperatures; and from these spots,50 proteins were successfully identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry（MALDI-TOF MS）.Bioinformatics studies on these proteins show that 57.8％ of these proteins were localized in the chloroplast.Of these proteins,8 ones have functions in photosynthesis,including glycine hydroxymethyltransferase,Rubisco large subunit,Rubisco activase,PSBO2,fructose-1,6-bisphosphate aldolase,NADP-dependent malate dehydrogenase,sedoheptulose bisphosphatase and photosystem Ⅱ reaction center PsbP family protein,suggesting that photosynthesis is greatly affected by cold stress.The identified proteins were validated by quantitative real-time polymerase chain reaction（qPCR）.Taken together,our results suggest that the chloroplast might also act as a cold stress sensor and that photosynthesis-related proteins may play important roles in cold acclimation for Arabidopsis.     

A History of Fischer-Tropsch Wax Upgrading at BP—— from Catalyst Screening Studies to Full Scale Demonstration in Alaska

Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carried out in dedicated micro-reactors and pilot plants, whose designs are critical to the performance selection. Variation in catalyst composition and defining the gas to oil feed ratios with the operating temperature are a few of the parameters studied. Product selection and maximizing diesel yield combined with stability (catalyst life) were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel per day demonstration plant. The products were also tested in engines to assess their combustion characteristics.     

COS hydrolysis in the presence of oxygen： Experiment and modeling

A mathematical model of COS hydrolysis on Al2O3, with fouling of catalyst, has been developed. Kinetic studies were carried out in a fixed bed reactor under atmospheric pressure and low temperature （40-70℃）. The effects of the COS inlet concentration, temperature, and relative humidity were analyzed. Experimental results of breakthrough curves were used to obtain kinetic parameters, which accounted for effects of S deposition on the inner-face of the catalyst. The model described the experimental breakthrough curves satisfactorily and well explained the performance of COS hydrolysis in the presence of oxygen. The exothermic heat of adsorption and activation energy, assuming Arrhenius type of temperature dependence of the equilibrium constant, were determined. Activation energy of COS hydrolysis and H2S oxidation were 35.9 kJ/mol, 19.6 kJ/mol; adsorption heat of H2O and H2S on Al2O3 were 45.1 and 60.1 kJ/mol respectively. Deactivation coefficient （α） was used to quantify the behavior of COS hydrolysis at different operating conditions. The effect of relative humidity on α is significant in the relative humidity range under study. Experimental data accorded well with model data in the studied range.     

Comparative study of kinetic modeling for the oxidative coupling of methane by genetic and marquardt algorithms

Overall kinetic studies on the oxidative coupling of methane, OCM, have been conducted in a tubular fixed bed reactor, using perovskite titanate as the reaction catalyst. The appropriate operating conditions were found to be: temperature 750-775 ℃, total feed flow rate of 160 ml/min, CH4/O2 ratio of 2 and GHSV of 100 min-1. Under these conditions, C2 yield of 28% was achieved. Correlations of the kinetic data have been performed with lumped rate equations for C2 and COx formation as functions of temperature, O2 and CH4 partial pressures. Six models have been selected among the common lumped kinetic models. The selected models have been regressed with the experimental data which were obtained from the Catatest system by genetic algorithm in order to obtain optimized parameters. The kinetic coefficients in the overall reactions were optimized by different numerical optimization methods such as: the Levenberg-Marquardt and genetic algorithms and the results were compared with one another. It has been found that the Santamaria model is in good agreement with the experimental data. The Arrhenius parameters of this model have been obtained by linear regression. It should be noted that the Marquardt algorithm is sensitive to the first guesses and there is possibility to trap in the relative minimum.     

Numerical analysis and experimental study of hydrogen production from dimethyl ether steam reforming

An experimental and theoretical study of steam reforming of dimethyl ether was carried out in a processor for fuel cell vehicles to explore the effect of temperature gradient and hydrogen content of the processor.A steady-state,laminar,two-dimensional axi-symmetric model was proposed to investigate the fluid flow,heat transfer and chemical reactions in the dimethyl ether steam reforming processor using porous medium approach.The numerical model was established with Star-CD program using SIMPLE algorithm and finite volume method.Experimental verification of the two-dimensional mathematical model was conducted.The numerical results coincided well with the experimental data.The effects of the parameters on the temperature gradient and hydrogen content of the processor were studied using the numerical model.     

Kinetic simulation of oxidative coupling of methane over perovskite catalyst by genetic algorithm： Mechanistic aspects

The reaction kinetics of oxidative coupling of methane catalyzed by perovskite was studied in a fixed bed flow reactor. At atmospheric pressure, the reactions were carried out at 725, 750 and 775 ℃, inlet methane to oxygen ratios of 2 to 4.5 and gas hourly space velocity (GHSV) of 100 min-1. Correlation of the kinetic data has been performed with the proposed mechanisms. The selected equations have been regressed with experimental data accompanied by genetic algorithm (GA) in order to obtain optimized parameters. After investigation the Langmuir-Hinshelwood mechanism was selected as the best mechanism, and Arrhenius and adsorption parameters of this model were obtained by linear regression. In this research the Marquardt algorithm was also used and its results were compared with those of genetic algorithm. It should be noted that the Marquardt algorithm is sensitive to the selection of initial values and there is possibility to trap in a local minimum.     

TRANSITION IN THE MELT OF FEP COPOLYMER

The nature of the transition in molten FEP copolymer was examined in relation to the enthalpy change, mechanical damping and melt viscosity. For a pre-heat-treated FEP copolymer sample a small endothermic peak appeared at 309—312 ℃in DSC trace with enthalpy change 0.03—0.05 cal/g. A peak was also detected in damping versus temperature curve at the same temperature range. The theological property of FEP copolymer melt was similar to that of liquid crystal, but no birefrigence was viewed in the melt. Therefore the transition was explained as the melting of small crystallites which persist in typical copolymer beyond its melting temperature. These crystallites can act as nuclei for crystallization upon cooling.     

BRITTLE-DUCTILE TRANSITION OF POLYMERS AND ITS PERCOLATION MODEL

The brittle-ductile transition (BDT) of particlc toughened polymers was extensively studied in terms ofmorphology, strain rate, and temperature. The calculation results showed that both the critical interparticle distance (ID_c) andthe brittle-ductile transition temperature (T_(BD)) of polymers were a function of strain rate. The ID_c reduced nonlinearly withincreasing strain rate, whereas T_(BD) increased considerably with increasing strain rate. The effects of temperature andplasticizer concentration on BDT were discussed using a percolation model. The results were in agreement with theexperiments.     

STUDIES ON THE RELATIONSHIP BETWEEN THE TR SPECTRA AND THE STRUCTURE OF SOME LINEAR Mo-Fe-S CLUSTERS

<正> The IR spectra of seven linear Mo-Fe-S clusters have been investigated. The characteristic frequencies VMo-st, VMo-sb, VFe-sb, VFe-spb and VFe-cl were assigned by comparing their vibratiional frequencies with the structural parameters and oxidation states of the metals in these clusters. The assignment of δS-Mo-S was attempted to approach. The influence ofMo atom on Vre-sb in the clusters containing heteronuclear MoS2Fe unit hasbeen discussed. The internal relationship and regularity between the characteristic frequencies and some structural parameters were demonstrated. Final a valuable parameter ΔV, which may be taken as a qualitative estimate of the extent of .Fe →Mo charge transfer in Mo-Fe-S clusters, was proposed.