Authors:Y. Xiong, D. Xu, Z. Chai, X. Li, Q. Tian, H. Zhou, W. Luo and X. Fang
The paper presents the results of determination of extractable organohalogens (EOX) by instrumental neutron activation analysis
(INAA), and polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) by gas chromatography (GC), in atmospheric
precipitation in Shanghai, China, from January to August 2005. The results showed that EOCI was the major component of organohalogens
in precipitation. A significant correlation between the concentrations of EOBr and EOI was observed (r2 = 0.75), which suggested that EOBr and EOI in precipitation might mainly come from the same sources. There were no clear
seasonal trends for the concentrations of EOX. The concentrations of ΣPCBs ranged from 0.2–2.8 ng/l, with the dominant PCBs
containing 3 to 5 chlorine atoms. HCH was the predominant pesticide in precipitation, accounting for over 80% of total OCPs,
in which β-HCH took 28%–72% of total HCH. Also, there may be an evidence for significantly historical usage of DDT.
Authors:Jiangang Yu, Jianguo Xu, Zhiqun Yu, Yi Jin, Jie Li and Yanwen Lv
A continuous-flow reactor (Corning G1 reactor) was hereby introduced for Fischer indole synthesis of 3-methylindole by reaction of phenyl hydrazines and propylaldehyde. Stoichiometric Lewis acid, ZnCl2, was supplied as catalyst as well as remover of NH3 which generated during the indole ring formation. Ionic liquid ([EMIM][BF4]) was employed as solvent according to its high-temperature tolerance and good product distribution. After a straightforward extraction process, 3-methylindole could be obtained in a 95.3% yield (96.0% purity) under optimized conditions. Ionic liquid (IL) was then recovered by another extraction process, and the recovered IL acted nearly as efficiently as new IL for this Fischer indole reaction.
Authors:Li Li, Wei Wang, Xiangshang Xu, Hui Wang, Shujie Liao, Wei Li, Weina Zhang, Dan Liu, Bo Cao, Shixuan Wang, Keng Shen and Ding Ma
Radioimmunotherapy (RIT) has emerged as an attractive and promising strategy for the management of malignant diseases. It
has been proven to be quite effective in the treatment of numerous tumors, such as non-Hodgkin lymphoma, metastatic prostate
cancer, melanoma, thyroid cancer, colon cancer and so on. The RIT currently used is mainly based on monoclonal antibodies
to recognize target antigens. As antibodies are large molecules, this method of RIT has some limitations in in vivo use, such
as the immunogenicity, the high costs and low efficiency of production. Aptamer is discovered and selected by SELEX technology.
As specific recognizers and binders, aptamers and antibodies have such a close similarity as to be interchangeable to some
extent. But, aptamers have many advantages over antibodies: higher affinity and specificity, smaller molecular weight, more
easily synthesized and modified, more rapidly penetrating into tumors, higher tumor-to-blood distribution ratio and more easily
to be cleared. In addition, since aptamer has almost no immunogenicity in vivo, it can be repeatedly administered. Thus, we
believe that aptamer-based RIT will be a feasible and promising way to treat human cancers, and it might display better results
in cancer treatment than antibody-based RIT. In conclusion, aptamer-based RIT is hopeful to become a key therapeutics in cancer
radiotherapy in the near future.
Authors:Xiao-Ling Xing, Feng-Qi Zhao, Shun-Nian Ma, Si-Yu Xu, Li-Bai Xiao, Hong-Xu Gao and Rong-Zu Hu
The thermal decomposition behavior of composite modified double-base propellant containing hexanitrohexaazaisowurtzitane (CL-20/CMDB propellant) was studied by microcalorimetry. The kinetic and thermodynamic parameters were obtained from the analysis of the heat flow curves. The effect of different proportion of CL-20 to the thermal decomposition behavior, kinetics, and thermal hazard was investigated at the same time. The critical temperature of thermal explosion (Tb), the self acceleration decomposition temperature (TSADT), and the adiabatic decomposition temperature rise (ΔTad) were calculated to evaluate the thermal hazard of the CL-20/CMDB propellant. It shows that the CMDB propellant with 38% CL-20 has relative lower values of E and lgA, and with 18% CL-20 has the highest potential hazard.
Authors:Li-Fang Song, Cheng-Li Jiao, Chun-Hong Jiang, Jian Zhang, Li-Xian Sun, Fen Xu, Qing-Zhu Jiao, Yong-Heng Xing, F. L. Huang, Yong Du, Zhong Cao, Fen Li and Jijun Zhao
One-three-dimensional metal-organic frameworks Mg1.5(C12H6O4)1.5(C3H7NO)2 (MgNDC) has been synthesized solvothermally and characterized by single crystal XRD, powder XRD, FT-IR spectra. The low-temperature molar heat capacities of MgNDC were measured by temperature modulated differential scanning calorimetry (TMDSC) over the temperature range from 205 to 470 K for the first time. No phase transition or thermal anomaly was observed in the experimental temperature range. The thermodynamic parameters of MgNDC such as entropy and enthalpy relative to reference temperature of 298.15 K were derived based on the above molar heat capacities data. Moreover, the thermal stability and decomposition of MgNDC was further investigated through thermogravimetry (TG)–mass spectrometer (MS). Three stages of mass loss were observed in the TG curve. TG–MS curve indicated that the oxidative degradation products of MgNDC are mainly H2O, CO2, NO, and NO2.
The low-temperature molar heat capacity of crystalline Mn3(HEDTA)2·10H2O was measured by temperature-modulated differential scanning calorimetry (TMDSC) for the first time. The thermodynamic parameters such as entropy and enthalpy relative to 298.15 K were calculated based on the above molar heat capacity data. The compound was characterized by powder XRD, FT-IR spectrum. Moreover, the thermal decomposition characteristics of Mn3(HEDTA)2·10H2O were investigated by thermogravimetry–mass spectrometer (TG–MS). The experimental result through TG measurement shows that a three-step mass loss process exists. H2O, CO2, NO, and NO2 were observed as products for oxidative degradation of Mn3(HEDTA)2·10H2O from the MS curves.
Authors:S.F. Dai, D.Y. Xu, Z.J. Wen, Z.P. Song, H.X. Chen, H.Y Li, J.R. Li, L.Z. Kang and Z.H. Yan
A novel 4.0-kb Fy was sequenced and bacterially expressed. This gene, the largest y-type HMW-GS currently reported, is 4,032-bp long and encodes a mature protein with 1,321 amino acid (AA) residues. The 4.0-kb Fy shows novel modifications in all domains. In the N-terminal, it contains only 67 AA residues, as three short peptides are absent. In the repetitive domain, the undecapeptide RYYPSVTSPQQ is completely lost and the dodecapeptide GSYYPGQTSPQQ is partially absent. A novel motif unit, PGQQ, is present in addition to the two standard motif units PGQGQQ and GYYPTSPQQ. Besides, an extra cysteine residue also occurs in the middle of this domain. The large molecular mass of the 4.0-kb Fy is mainly due to the presence of an extra-long repetitive domain with 1,279 AA residues. The novel 4.0-kb Fy gene is of interest in HMW-GS gene evolution as well as to wheat quality improvement with regard to its longest repetitive domain length and extra cysteines residues.
Authors:Hui-Zhou Gao, Qi Yang, Xiao-Yan Yan, Zhu-Jun Wang, Ji-Li Feng, Xia Yang, Sheng-Li Gao, Lei Feng, Xu Cheng, Chao Jia and Ke-Wu Yang
In an effort to probe the reaction of antibiotic hydrolysis catalyzed by B3 metallo-β-lactamase (MβL), the thermodynamic parameters of penicillin G hydrolysis catalyzed by MβL L1 from Stenotrophomonas maltophilia were determined by microcalorimetric method. The values of activation free energy ΔG≠θ are 88.26, 89.44, 90.49, and 91.57 kJ mol−1 at 293.15, 298.15, 303.15, and 308.15 K, respectively, activation enthalpy ΔH≠θ is 24.02 kJ mol−1, activation entropy ΔS≠θ is −219.2511 J mol−1 K−1, apparent activation energy E is 26.5183 kJ mol−1, and the reaction order is 1.0. The thermodynamic parameters reveal that the penicillin G hydrolysis catalyzed by MβL L1 is an exothermic and spontaneous reaction.
A novel two-dimensional metal organic framework MgBTC [MgBTC(OCN)2·2H2O, where BTC = 1,3,5-benzenetricarboxylate] has been synthesized solvothermally and characterized by single crystal XRD, powder
XRD, FT-IR spectra. The low-temperature molar heat capacities of MgBTC were measured by temperature modulated differential
scanning calorimetry (TMDSC) over the temperature range from 190 to 350 K for the first time. No phase transition or thermal
anomaly was observed in the experimental temperature range. The thermodynamic parameters of MgBTC such as entropy and enthalpy
relative to reference temperature of 298.15 K were derived based on the above molar heat capacities data. Moreover, the thermal
stability and decomposition of MgBTC was further investigated through thermogravimetry (TG)-mass spectrometer (MS). Four stages
of mass loss were observed in the TG curve. TG-MS curve indicated that the products of oxidative degradation of MgBTC are
H2O, N2, CO2 and CO. The powder XRD showed that the mixture after TG contains MgO and graphite.
Authors:Yi-Xi Zhou, Li-Xian Sun, Zhong Cao, Jian Zhang, Fen Xu, Li-Fang Song, Zi-Ming Zhao and Yong-Jin Zou
Two metal–organic frameworks (MOFs) of M(HBTC)(4,4′-bipy)·3DMF [M = Ni (for 1) and Co (for 2); H3BTC = 1,3,5-benzenetricarboxylic acid (1,3,5-BTC); 4,4′-bipy = 4,4′-bipyridine; DMF = N,N′-dimethylformamide] were synthesized by a one-pot solution reaction and a solvothermal method, respectively, and characterized by powder X-ray diffraction and FT-IR spectra. The low-temperature molar heat capacities of M(HBTC)(4,4′-bipy)·3DMF were measured by temperature-modulated differential scanning calorimetry (TMDSC) for the first time. The thermodynamic parameters such as entropy and enthalpy relative to reference temperature 298.15 K were derived based on the above molar heat capacity data. Moreover, the thermal stability and the decomposition mechanism of M(HBTC)(4,4′-bipy)·3DMF were investigated by thermogravimetry analysis (TGA). The experimental results through TGA measurement demonstrate that both of the two compounds have a three-stage mass loss in air flow.