以一种新型Gemini表面活性剂作为介孔模板剂通过转晶过程合成介孔ZSM-5分子筛

将一种新型Gemini表面活性剂,丙撑基双(十八烷基二甲基氯化铵)[C18H37(CH3)2–N+–(CH2)3–N+–(CH3)2C18H37]Cl2(C18-3-18),作为介孔模板剂用于水热法合成介孔ZSM-5分子筛.结果表明,在130 oC低温晶化即可高效合成介孔ZSM-5分子刷.C18-3-18的加入量可影响到所合成介孔ZSM-5分子筛的相对结晶度和织构性质,它的形成遵从一个转晶过程.在合成初期,凝胶中介孔模板剂C18-3-18的使用导向了介孔材料的生成;随后在TPABr的模板作用下,介孔材料慢慢转晶生成具有MFI结构的介孔ZSM-5;然后所合成的介孔ZSM-5晶粒进一步长大并聚集形成块状颗粒,同时产生晶间介孔.C18-3-18作为介孔导向剂不仅可用于合成介孔ZSM-5分子筛,也可用于其它介孔分子筛的合成中.     

纤维二糖与葡萄糖催化转化制备乙二醇(英文)

选用纤维二糖作为探针分子,探索纤维素催化转化制备乙二醇过程的反应路径.分别考察了纤维二糖和葡萄糖在双组分催化剂H2WO4和Ru/C下的催化反应活性.结果表明,乙二醇不仅来自于纤维二糖水解产物葡萄糖的逆羟醛缩合作用,同时也可以来自于纤维二糖的直接逆羟醛缩合过程.而且,纤维二糖的直接逆羟醛缩合作用对糖苷键的水解也有一定的促进作用.比较发现,钨基催化剂作用下纤维二糖的逆羟醛缩合反应活性比葡萄糖要低,因此乙醇醛可以缓慢产生并在Ru/C催化剂上迅速加氢生成乙二醇.使得以纤维二糖作为原料比以葡萄糖作为原料时获得更高的乙二醇收率.     

Opening Band Gap of Graphene by Chemical Doping: a First Principles Study

Single atom chemically doped graphene has been theoretically studied by density functional theory. The largest band gap, 0.62 eV, appears in arsenic atom doped graphene, then 0.60 eV comes by the tin atom, whose deformations can neither be ignored. It is also found that oxygen and iron single atom embedded graphene can open band gap by 0.52 and 0.54 eV, respectively. Moreover, doping O atom shows little distortion and high stability by charge redistribution. The band gap of Fe doped graphene is opened by orbital hybridization. The other heteroatom doped results are a little inferior to them.     

Syntheses,Crystal Structures,and Biological Activities of Two 5-Pyrimidinyl-1,2,4-oxadiazoles

Two 5-pyrimidinyl-1,2,4-oxadiazoles were synthesized through two different routes and their structures were characterized by single-crystal X-ray diffraction, NMR and MS. Compound 3, 5-(2-chloro-4-methyl-6-phenylpyrimidin-5-yl)-3-phenyl-1,2,4-oxadiazole, crystallizes in orthorhombic, space group Pbca with a = 19.1575(11), b = 8.2115(5), c = 21.2035(12), V = 3335.6(3)3 and Z = 4. Compound 6, 5-(2,6-dichloropyrimidin-4-yl)-3-phenyl-1,2,4-oxadiazole, crystallizes in monoclinic space group Pn with a = 8.4275(13), b = 5.4088(8), c = 13.493(2), β = 99.768(3)o, V = 4658.6(6)3 and Z = 8. Preliminary bioassay indicated that the two title compounds had good herbicidal activities.     

Influence of Cell Disruption and Elution on Cellulase Release of Clostridium straminisolvens (CSK1)

Clostridium straminisolvens (CSK1) is a novel cellulolytic bacterium isolated from a cellulose-degrading bacterial community MC1. In this study, the influence of the following cell disruption and elution methods on CSK1cellulase release was investigated: (1) freezing–thawing, (2) ultrasonication, (3) elution, (4) freezing–thawing following elution, (5) ultrasonication following elution, and lastly (6) high-pressure homogenization following elution. The activity of the cellulases CMCase, β-glucosidase, Avicelase, FPase, and xylanase in crude extracts increased 81.5, 23.8, 87.7, 46.3, and 51.7 %, respectively, with an observed optimal treatment method for each cellulase type. The release of protein from CSK1 cells increased following either cell disruption or elution and was highest at 88.3 % in the homogenization high pressure following elution treatment. A newly observed protein was present following cell elution. The performance of cell elution as determined by real time-PCR indicated that the first time cell elution removed more than 90 % of the CSK1 cells from the substrate. These findings demonstrate that cell disruption and elution are effective methods for inducing cellulase release, and elution is the key step for CSK1. To our knowledge, this study presents the first evidence of optimal treatments for induction of cellulase release of Clostridium straminisolvens. This information will be of great value for use in subsequent efforts to better understand the cellulase characteristics of CSK1 and cellulose degradation mechanisms of the MC1 community.     

Antibiotic Resistance Capability of Cultured Human Colonic Microbiota Growing in a Chemostat Model

To evaluate the potential antibiotic resistance capability of cultured human colonic microbiota as a whole system when residual antibiotics enter the human intestine, the combination of viable cell counting and denaturing gradient gel electrophoresis (DGGE) method was used to study effects of the enrofloxacin (ENR) residue on the microbial diversity, antibiotic resistance, and anti-colonization capability in a human chemostat model. The results indicated that the ENR enhanced the microbial antibiotic resistance to the ciprofloxacin (CI), and a dose-dependent effect was observed. When exposed to 1.25 μg/mL ENR, the growth of the tested bacteria (e.g., total aerobic bacteria, total anaerobic bacteria, Lactobacillus, Enterococci, Escherichia coli, Bacteroides fragilis) received little change, while the microbial diversity in this group was totally changed; In 12.5- and 125-μg/mL ENR group, the quantities and microbial diversity received a dramatic change compared to their no drug stage, while the addition of the cultured human colonic microbiota to the probiotic group did enhance the colonization resistance (CR) of the cultured microbiota to Candida albicans SC5314, indicating its potential beneficial effect on human intestinal healthy and anti-infection capability.     

Cobalt(II) and silver(I) coordination polymers constructed from flexible bis(5,6-dimethylbenzimidazole) and substituted isophthalate co-ligands

Two coordination polymers, [Co(L1)(IPA] _n (1) and {[Ag(L2)(HMIPA)]·H₂O} _n (2) (H₂IPA = isophthalic acid, L1 = 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H₂MIPA = 5-methylisophthalic acid, L2 = 1,6-bis(5,6-dimethylbenzimidazol-1-yl)hexane, have been synthesized and characterized by physicochemical and spectroscopic methods, as well as single-crystal X-ray diffraction. In 1, six-coordinated cobalt centers are bridged by L1 and IPA^2? ligands to generate a (4,4) two-dimensional layer. However, complex 2 features a 1D chain structure, which is further extended by O–H···O hydrogen bonding interactions into a 2D supramolecular layer with (6³) topology. The fluorescence and thermal gravimetric analysis of both complexes were also explored. Furthermore, the complexes 1 and 2 exhibit remarkable catalytic properties for the degradation of methyl orange dyes in a Fenton-like process.     

Fabrication of anisotropic silica hollow microspheres using polymeric protrusion particles as templates

Anisotropic polystyrene/poly(styrene-co-divinylbenzene) (PS/P(S-DVB)) protrusion particles with various morphologies such as eyeball-like, snowman-like, and raspberry-like were synthesized using a modified seeded polymerization method by dynamically controlling and stabilizing the phase separation. The effects of swelling agent, crosslinker, and monomer concentrations on the particle morphologies were studied. Using the PS/P(S-DVB) protrusion particles as templates, anisotropic silica (SiO₂) hollow microspheres were fabricated facilely. The obtained anisotropic silica hollow spheres had a potential application in rapid waste removal and detoxification extraction with a very simple procedure.     

双核铜配合物Cu2(2,2′-bpy)2(2-bba)4的合成、表征与晶体结构

在室温下,以2-溴苯甲酸和2,2'-联吡啶为配体,通过溶液法在甲醇/水的混合溶剂中反应合成了双核铜(II)配合物Cu2(2,2'-bpy)2(2-bba)4。通过元素分析、红外光谱、热重测试技术和X射线粉末衍射对其进行了结构表征,同时用X射线单晶衍射分析确定了其晶体结构。结果表明,其晶体属正交晶系,空间群为Pbca,晶胞参数:a=20.619(4),b=10.098(2),c=21.865(4),V=4552.5(15)3,Dc=1.808g·cm-3,μ=4.505mm-1,F(000)=2440.0,Z=4,最终残差因子R1=0.0583,wR2=0.1200。配合物为双核结构,每个结构单元中2个Cu(II)离子通过2个2-溴苯甲酸根配体单齿桥联。配合物中的每个Cu(II)离子为五配位的结构,分别和来自2个单齿桥联的2-溴苯甲酸根的2个氧原子、1个单齿配位的2-溴苯甲酸根的1个氧原子及来自1个2,2'-联吡啶的2个氮原子配位形成了畸变的四方锥型结构,分子间则通过弱的C—H…O氢键作用形成了一维链状的结构。CCDC:972827。     

真空离心浓缩/气相色谱-质谱联用法测定白酒中6种邻苯二甲酸酯类增塑剂

建立了测定白酒中6种邻苯二甲酸酯类增塑剂的真空离心浓缩/气相色谱-质谱联用(GC-MS)分析方法。样品经真空离心浓缩,正己烷提取,取上层正己烷,4000r/min离心5min,采用GC-MS测定,外标法定量。在0.10～5.00μg/mL范围内,相关系数r20.992,样品在0.10～2.00 mg/kg范围内加标,平均回收率在88.83%～111.67%之间,相对标准偏差(RSD)为4.85%～11.35%,检出限(LOD)在0.02～0.05 mg/kg之间。采用该方法对16个白酒样品进行测定,结果表明该法简便、快速、结果准确可靠、灵敏度高,能够满足白酒中6种邻苯二甲酸酯增塑剂检测需求。