STUDIES IN MONKEYS OF ATTENUATED HEPATITIS A VARIANTS

Three HAV variants, H2M20(35℃), H2M20(32℃) and H2M20K5(32℃), were developed by passagein different tissue culture cells and at different temperatures. Virulence for monkeys was assessed by in-oculating each of the variants into four monkeys. Weekly bleeding through 16 weeks post-inoculation wasassayed for anti-HAV titers and SGPT as well as LDH5 activities. And in some monkeys liver biopsieswere also studied. Seroconversion was induced in all of the inoculated monkeys. The anti-HAV titers test-ed at 16 weeks post-inoculation were: 40-640 with H2M20(35℃), 40-160 wi1h H2M20(32℃) and 20-40 with H2M20K5(32℃). These variants showed different levels of virulence/attenuation for monkeys.Variant H2M20(35℃) showed no evidence of attenuation, variant H2M20(32℃) retained slight virulenceand variant H2M20K5(32℃) showed no evidence of virulence for monkeys. Criteria are proposed for as-say of HAV virulence tested in monkeys.     

JOURNAL OF NATURAL GAS CHEMISTRY CONTENTS OF VOLUME 3 February 1994 Volume 3 Number 1

Preparation and characteriration of bimetallic Pd-Fe/Al_2O_3 catalysts—Characterization by infrared spectroscopy and X-ray diffraction……………………………………………………XIAO,T.C.;AN,L.D.;TANG,A.H.;XU,X.L.(1)Preparation and characterization of bimetallic Pd-Fe/Al_2O_3 catalysts-Characterization by TEM,EDX,XPS and ESR…………………………XIAO,T.C.;AN,L.D.;TANG,A.H.;LI,S.L.;XU,X.L.(13)Effect of phosphorus addition to ZrO_2/SiO_2 on catalytic properties for dehydrogenation ofmethanol…………………………………………………………ZHANG,F.X.;MA,J.;XU,P.P.(24)Study of TPD and kinetics on NO+CO over copper-substrate catalysts……………………………………………………………………………………LU,G.Z.;WANG,R.(35)Effect of pelleting pressures on global reaction rates of methanol synthesis over CU-basedcatalyst……YAO,P.F.;LIU,G.J.;ZHU,B.C.(44)Selective oxidation of propane over α-Bi_2Mo_3O_(12)/MoO_3catalyst……WU.T.H.;YU,J.F.;YANG,H.M.;WAN,G.J.;JIANG,Y.Z.LI,Y.G.(53)Activity and selectivity of ruthenium carbonyl,ke     

CLONING IN Yersinia enterocolitica OF K99 ANTIGEN GENE FROM Escherichia coli

A recombinant plasmid pFS239 containing the geoe coding for K99 antigen of Escherichia coli and wide-host-range plasmid pKT230 has been cloned in E. coli C600. pFS239 has been transferred to Yersinia enterocolitica strains D29, L15 and L15 (pYV15) through triparental mating. In Y. enterocolitica transconjugants the expression of VW antigens and calcium dependence which represent the propertics associated with the virulence plastmid of Y. enterocolitica remains unchanged.     

Low-temperature heat capacities and thermodynamic properties of rare-earth triisothiocyanate hydrates (Ⅲ)——Sm(NCS)_3·6H_2O,Gd(NCS)_3·6H_2O,Yb(NCS)_3·6H_2O and Y(NCS)_3·6H_2O

The heat capacities of four RE isothiocyanate hydrates,Sm( NCS)3 6H2O,Gd( NCS)3 6H2O,Yb(NCS)3 6H2O and Y( NCS)3 6H2O,have been measured from 13 to 300 K with a fully-automated adiabatic calorimeter No obvious thermal anomaly was observed for the above-mentioned compounds in the experimental tem-peiatnre ranges.The polynomial equations for calculating the heat capacities of the four compounds in the range of 13-300K were obtained by the least-squares fitting based on the experimental Cp data.The Cp values below 13 K were estimated by using the Debye-Einstem heat capacity functions.The standard molar thermodynamic functions were calculated from 0 to 300 K.Gibbs energies of formation were also calculated.     

PREPARATION OF POLYMER-SUPPORTED RCpCpTiCl_2 AND APPLICATION IN CATALYTIC ISOMERIZATION OF 1,5-HEXADIENE

Polymer-supported RCpCpTiCl2 (Cp =η5-C5H4; RCp = η5-RC5H4) have been prepared and reduced by i-C3H7MgBr in situ , then used in catalytic isomerization of1,5-hexadiene. The isomerization of 1, 5-hexadiene leads to a mixture of cyclic and linear products. The ratio of cyclic to linear product depends on the nature of the supporter and the substituent on the cyclopentadienyl ring. The former contributes themost, for example, silica supported Cp2TiCl2 gave cyclic-linear ratio of 99/1,while for polymer-supported Cp2TiCl2 species, linear compounds are the major products and the ratio of cyclic to linear product changes with different R groups on the cyclopentadienyl ring.     

CHEMICAL MODIFICATION OF THE SURFACE OF CALCIUM ALGINATE GEL BEADS

The chemical modification of the surface of calcium alginate gel beads (CAGB) via grafting copolymerization with vinyl acetate (VAc) was studied. The optimum reaction conditions with activation and graft copolymerization two steps were explored. First, 5 grams CAGB with 2.5 mm initial diameter was initiated with 0.0493 mol/L K2S208 at 51℃ for 30 min in 15 mL 1% PVA/H2O. Then 4.34 mol/L VAc was added dropwise and the reaction was allowed to proce at 48℃ for 3 h. The grafting efficiency could come up to 30%. It was found the stability of modified CAGB in the air and in electrolyte solutions was greatly improved.     

IDENTIFICATION OF NATURALLY OCCURRING TEMPERATURE-SENSITIVE STRAINS OF INFLUENZA A VIRUS AND LOCATION OF THEIR GENETIC LESIONS

Influenza A viruses of different subtypes isolated in different years and from differentparts of China were examined for temperature-sensitiveness (ts ) in their early egg passages.The validity of ts character has been confirmed by ti1e results of parallel tests in chickembryos and in cell cultures. From 12 strains of the old H1N1 subtype isolated between1949 and 1957, no ts strain was detected. Two out of 6 strains of new H1N1 isolated afterFebruary 1979 were found to be ts. For the H3N2 subtype, only 8 out of 23 strainsisolated between 1968 and 1978 were ts, but the proportion increased abruptly to 13 out of15 strains isolated in 1979--1980. We also found 6 out of 16 strains of the R2N2 subtypeto be ts. Two H2N2 and one H3N2 strains examined were found to be composed of mixedts and ts~ particles. By rocombination- complementation test against 7 standard ts strains ofWSN virus with known genetic lesions, the ts lesion of the H3N2 strain Hong Kong/8/68was located on the nucleoprotein gene, whereas that of the H1N1 strain Tianjin/78/77 waslocated on the matrix protein gene.     

CRYSTAL AND MOLECULAR STRUCTURE OF STEMOTININE

<正> C18H25NO5, Mr = 335.40, tetragonal, P41212, a = 15.578(4), c =14.723(3) A, V =3573(2) A3, Z = 8, D = 1.247 g cm-3, MoKα,λ= 0.71069 A, μ = 0.;85 cm-1, T = 293K, final R .= 0.100 and RW (on F2) = 0.080 for 1095 observed data [|FO| > 2σ(|FO|)]. The structure confirms the spectrbscopic assignment of a pentacyclic skeleton containing two α-methyl-γ-lactone rings, one ether and one tertiary amine.     

A Y(Ⅲ)-organic Coordination Polymer Constructed from 2-(Pyridine-4-yl)-1H-imidazole-4,5-dicarboxylate and Oxalate Ligands: Structure and Luminescent Property

A novel compound, {[Y(HPIDC)(OX)1/2(H2O)]·2H2O}n (1, H3PIDC = 2-(pyridin-4- yl)-1H-imidazole-4,5-dicarboxylic acid, H2OX = oxalic acid), has been synthesized under hydrothermal conditions and characterized by thermal analysis (TGA), powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction. Complex 1 crystallizes in monoclinic space group P21/c with a = 8.342(8), b = 14.61(1), c = 11.487(1), β = 90.78(9)°, V = 1400.4(2)3, Z = 4, C11H11N3O9Y, Mr = 418.14, Dc = 1.983 g/cm3, F(000) = 836, Rint = 0.0509, T = 293(2) K, μ = 4.240 mm-1, the final R = 0.0477 and wR = 0.1125 for 2770 observed reflections with I > 2σ(I). Compound 1 exhibits a 3D framework and generates the 1D open channels filled with free water molecules. The structure of 1 can be rationalized as a diamondoid network when the atom yttrium is regarded as a 4-connected node linking four surrounding yttrium atoms. The luminescent property of compound 1 is also investigated.     

PREPARATION OF POLYMER—SUPPORTED RCpCpTiCl2 AND APPLICATION IN CATALYTIC ISOMERIZATION OF 1,5—HEXADIENE

Polymer-supported RCpCpTiCl2(Cp=η^5-C5H4;RCp=η^5-RC5H4)have been prepared and reduced by i-C3H7MgBr in situ，then used in catalytic isomerization of 1,5-hexadiene.The isomerization of 1,5-hexadiene leads to a mixture of cyclic and linear products.The ratio of cyclic to linear product depends on the nature of the supporter and the substituent on the cyclopentadienyl ring.The former contributes the most,for example,silica supported Cp2 TiCl2 gave cyclic-linear ratio of 99/1,while for polymer-supported Cp2TiCl2 species,linear compounds are the major products and the ratio of cyclic to linear product changes with different R groups on the cyclopentadienyl ring.     

近期热点文章

正关键词:机器学习·CO_2还原·Cu基催化剂Y. Guo, X. R. He, Y. M. Su, Y. H. Dai, M. C. Xie, S.L. Yang, J. W. Chen, K. Wang, D. Zhou, C. Wang,Machine-Learning-Guided Discovery and Optimization of Additives in Preparing Cu Catalysts for CO2Reduction, J. Am. Chem. Soc., 2021, 143(15):5755-5762.厦门大学汪骋教授与周达副教授通过"实验测试→机器学习分析→预测和重新设计"三个迭代周期,     

EFFECTS OF K_2O AND MnO PROMOTERS ON THE PRODUCTION OF LIGHT ALKENES VIA SYNGAS OVER Fe/SILICALITE-2 CATALYST I.ACTIVITY OF K-Fe-MnO/SILICALIT-2 CATALYST

The activity and the selectivity to light alkenes of silicalite-2 (Si-2) zeolite supported F'e catalyst tor CO hydrogenation can he improved obviously with the addition of K2O and MnO promoters. The results of CO hydrogenation, CO-TPD, CO/H2-TPSR, C2H4/H2-TPSR and C2H4/H2 pulse reaction over K-Fe-MnO/Si-2 catalysts clearly show that the K2O additive into Fe-MnO/Si-2 catalyst leads to a remarkable increase in both the capacity and strength of the strong CO ad-species that will produce much more |Cad| via their disproportionation at higher temperatures. This results in an increase in the CO conversion and the selectivity to light olefins, and a decrease in CH4 formation. Moreover, K2O can suppress the disproportionate of C2H4 that occurs during the reaction as a side-reaction Meanwhile, the MnO promoter mainly prohibits the hydrogenation of C2H4 and C3H6, which is favorable to enhancing the selectivity to C2H4 and C3H6 and decreasing the formation of C2H6, and C3H8. It is also of interest that MnO has har     

SMALL-BORE COLUMNS OF 1 mm I. D. FOR HPLC

The performance of small-bore columns of 1 mm I. D. for HPLC is described. The effect of mobile phase velocity and connecting effect on the values of H, a′, b′ and β are investigated. By operating at mobile phase velocity of 0.8 mm/s, the column of 200×1 mm I. D. packed with YWG-5μm (silica gel) can give the efficiency of about 11,000 plates which meet the needs of ordinary analysis. Oompared with column of 150×2 mm I. D., the solvent consumption is reduced to 1/3. The value of n~∞/t_r~0 about 700 T. P./s can be obtained. But the value of β is rather large. It needs further to be improved. Coupling 5 columns of 200×1 mm I. D., the efficiency of about 50,000 plates can be obtained. For a column of 1000×1 mm I. D. packed directly, the efficiency of 70,000 plates was achieved. Some applications of 1 mm I. D. column are given. We propose to use the column of 200×1mm I. D. in the routine analysis.     

SYNTHESES AND ADSORPTION PROPERTIES OF PHENOL-FORMALDEHYDE-TYPE CHELATING RESINS BEARING THE FUNCTIONAL GROUP OF TARTARIC ACID

Several kinds of novel chelating resins bearing the functional group of tartaric acid (TTA-FQ-12, TTA-FQ-23, and TTA-FQ-34) were synthesized by reacting epoxy maleic anhydride, which was prepared through the oxidization reaction of maleic anhydride by hydrogen peroxide, with phenol-formaldehyde resin containing polyamine (FQ resins series). The effects of such factors as reaction time, reaction temperature and pH value on the loading capacity of TTA in resins were investigated. The results showed that the optimum reaction conditions are as follows: time 9-12h; temperature 90-105℃;pH value 6-10. The loading capacities of TTA can reach 0.15, 0.14, and 0.11 mmol/g^-1 when the functional group of FQ resin was -OCH2CH2NHC2H4NH2, -O(CH2CH2NH)2C2H4NH2 and -O(CH2CH2NH)3C2H4NH2), respectively. The structures of resins were characterized by FTIR spectra. The primary study on the adsorption properties of the resins for metal ions showed that there are two kinds of adsorption mechanisms i.e. ion exchange and chelate in the adsorption process. TTA-FQ resins have much higher adsorption selectivity for Pb^2 and Zn^2 than for Cu^2 and Ni^2 . These resins can probably be used for separating Pb^2 or Zn^2 in the mixture of metal ions or for treating wastewater containing heavy metal ions.     

D152树脂对铜(Ⅱ)的吸附性能

The sorption behavior and mechanism of D152 resin for Cu~(2+) is investigated.D152 resin has a good adsorptivity for Cu~(2+) in the HAc-NaAc medium at pH=4.73.The statically saturated sorption capacity is 309mg/g·(resin).Cu~(2+)adsorbed on D152 resin can be eluted quantitatively by using 0.1-2.0mol/L hydrochloric acid as an eluant.The apparent rate constant and activation energy are k_(298)=1.86×10~(-5) sec~(-1) and Ea=12.3kJ/mol.The sorption behavior of D152 resin for Cu~(2+) obeys the Freundlich isotherm.The sorption thermodynamic parameters of D152 resin for Cu~(2+)are enthalpy change ΔH=14.6 kJ/mol,free energy change ΔG=-0.72kJ/mol,entropy change ΔS=51.4J/(mol·K).respectively.     

CHEMILUMINESCENCE OF BaO UNDER SINGLE-COLLISION CONDITION

The results of Ba N_2O reaction studied in the crossed molecular beam experiment are presented briefly. By optical multichannel analyser observation of chemiluminescence angular distribution of the reaction coupled with the estimation of the radiative lifetime of the emitting states produced from the reaction, and by analysis of the chemiluminescence spectrum with partially well-defined bandheads obtained under the single collision reaction condition as well as by the fact that the chemiluminescence photon yield enhanced by reacting Ba(~3D) with ground state N_2O, the origin of the chemiluminescence is proved to be both the A~1Σ~ and A′~1 to X~1Σ~ emission of BaO. The reaction mechanism for Ba(~3D) N_2O is interpreted reasonably by the suggestion that the formation of ion pair, Ba~ N_2O~- initiates the reaction. According to this model and the phase space statistical approximation, the branching ratios for various electronic states of BaO produced in Ba(~3D) N_2O reaction have been calculated, whic     

ETHYLENE POLYMERIZATION AND COPOLYMERIZATION WITH POLAR MONOMERS BY A NEUTRAL NICKEL CATALYST COMBINED WITH CO-CATALYST OF Ni（COD）2 OR AL（i-Bu）3

A neutral nickel (Ⅱ) catalyst D, { [O-(3-cyclohexyl)(5-Cl)C6H2-ortho-C(H)=N-2,6-C6H3(i-Pr)2]Ni(Ph3P)(Ph)} has been synthesized and characterized by 1H-NMR, FTIR and elemental analysis. The results indicate that Al(i-Bu)3 is an effective cocatalyst for the neutral nickel catalyst. With bis(1,5-cyclooctadiene) nickel(0) [Ni(COD)2] or Al(i-Bu)3 as a cocatalyst, the neutral nickel catalyst D is active for ethylene polymerisation and copolymerisation with polar monomers (tertbutyl 10-undecenoate(BU), methyl 10-undecenoate (MU), allyl alcohol (AA) and 4-penten-1-ol (PO)) under mild conditions.The resulting polymers were characterized by 1H-NMR, FTIR, DSC, and GPC. From the comparative studies, Ni(COD)2 is more active than Al(i-Bu)3 for ethylene homopolymerization, while Al(i-Bu)3 is more effective than Ni(COD)2 for ethylene copolymerisation with polar monomers. The polymerization parameters which affect both the catalytic activity and properties of the resulting polyethylene were investigated in detail. Under the conditions of 20 μmol catalyst D and Ni(COD)2/D = 3(molar ratio) in 30 mL toluene solution at 45℃, 12 × 105 Pa ethylene for 20 min, the polymerization activity reaches as High as7.29×105gPE.(mol.Ni·h)-1and Mηis 7.16×104g.mol-1.For ethylene copolymerization with polar monomers,the effect of comonomer concentrations was examined. As high as 0.97 mol% of MU, 1.06 mol% of BU, 1.04 mol% of AA and 1.37 mol% of PO were incorporated into the polymer, respectively, catalyzed by D/Al(i-Bu)3 system.     

Open-framework Borophosphate:(NH4)_(0.5)Fe~II_(0.5)Fe~III_(0.5)(H_2O)_2BP_2O_8·0.5H_2O

We are investigating the synthesis and properties of a new class of open framework borophosphate solids with the goal of being able to use in optical devices and magnetic materials. Only a few open-framework ferric borophosphate compounds with a chiral tetraheda-tetraheda helices, KFe(H2O)2BP2O8)H2O(1), Fe(H2O)2BP2O8H2O(2), (NH4)0.4-FeII0.55FeIII0.5(H2O)[BP2O8]0.6H2O(3) have been reported by Boy et al.1, Ylmaze et al.2 and Huang and Schfer et al.3. However, Huang and Schfer et…     

DEPOLYMERIZATION AND KINETICS OF DEPOLYMERIZATION OF POLYETHYLENE TEREPHTHALATE USING DIBUTYLTIN OXIDE CATALYST

Depolymerization of poly（ethylene terephthalate） （PET） was performed in the tubular bomb microreactor which contained the solution of PET in methanol and dibutyltin oxide at the temperature ranging from 433 K to 473 K, the reaction time from 5 to 45 min and the catalyst-to-PET ratio of 0.3%-2% by weight. The optimal condition for PET depolymerization catalyzed by dibutyltin oxide is the temperature of 443-453 K, the reaction time of 20-25 min and 0.8% by weight of catalyst. By using differential methods, the activation energy for the depolymerization process was found to be 154.05 kJ/mol in the temperature range from 433-463 K.