菜豆环氧水解酶归一性水解间硝基环氧苯乙烷的研究

旨在研究菜豆环氧水解酶PvEH2对映归一性水解外消旋(rac-)间硝基环氧苯乙烷(mNSO)的特性,为制备光学纯(R)-间硝基苯乙二醇(mNPED)提供优良的生物催化剂。构建表达有重组PvEH2的工程菌E.coli/pveh2。以rac-mNSO为底物,借助手性色谱法分析E.coli/pveh2全细胞的EH活性和区域选择性。基于有机助溶剂种类和剂量对酶活性的影响,筛选并优化缓冲液/助溶剂反应体系。结果显示,在菜豆植株中,PvEH2基因的转录水平可能受体外环境诱导因素的影响。E.coli/pveh2的EH活性为15.4 U/g,水解反应的区域选择性系数αS和βR分别为90.3%和96.4%。在经过筛选优化的含有5%(V/V)丙三醇的磷酸干细胞盐缓冲液中,最高底物浓度为40 mmol/L,是原缓冲液体系的4倍。当反应至12 h时,所得(R)-mNPED的光学纯度eep及产率分别为84.9%和90.2%。E.coli/pveh2或PvEH2在水解rac-mNSO中表现出优秀的区域选择性,在制备光学纯(R)-mNPED中具有较好的应用潜力。

4,6-二硝基-7-氧-苯并氧化呋咱钾一水合物(KDNP·H_2O)的合成、晶体结构与性能

2,4,6-三硝基间苯二酚铅(LTNR)的主要缺点是静电感度过高以及含铅对人体、环境造成危害。为了寻找LTNR的替代物,采用两步法合成了4,6-二硝基-7-氧-苯并氧化呋咱钾一水合物(KDNP·H_2O)。利用溶剂蒸发法获得了该化合物的单晶。利用元素分析、红外光谱法、核磁共振氢/碳谱法和单晶X-衍射对其结构进行了表征。按国军标GJB-5891测试了其感度,计算了爆热。根据Kamlet-Jacobs方程计算了该化合物的爆轰参数。结果表明,该晶体为三斜晶系,空间群为P-1,有一个结晶水。该起爆药撞击感度为21.3 cm,静电感度为0.69 J,摩擦感度为56%,火焰感度为为24.7 cm,爆热为3.50 kJ·kg^(-1),爆速为6.77 km·s^(-1)、爆压为21.25 GPa,显示KDNP·H_2O是一种无铅安全环保的起爆药。

12-(4-硝基苯氧甲基)-5-卤代苯-1,3,4-噁二唑的合成与结构表征

以4-硝基苯氧乙酰肼为原料,经N,N′-二酰基肼3,最后脱水环化合成了最终产物2-(4-硝基苯氧甲基)-5-卤代苯基-1,3,4-噁二唑4,收率在90%以上。通过IR、1HNMR对化合物3、4的结构进行了表征。

固相萃取-高效液相色谱荧光检测法测定人血浆3-硝基酪氨酸含量

建立了人血浆中痕量3-硝基酪氨酸的高效液相色谱-荧光检测法。血浆经乙腈沉淀蛋白后,上清液用氮气吹干,残渣复溶后过C18固相萃取小柱净化浓缩,洗脱液再用氮气吹干,残渣进行荧光衍生化反应。采用高效液相色谱分离,荧光检测器检测,外标法定量。3-硝基酪氨酸在0.50～50.0nmol/L范围内线性关系良好,相关系数为0.9999;样品加标绝对回收率为89.3%～91.9%,相对回收率为99.2%～107.9%;日内相对标准偏差为1.46%～4.79%,日间相对标准偏差为2.75%～9.20%;在血浆中检出限为0.25nmol/L;测定正常人血浆中3-硝基酪氨酸平均浓度为1.18nmol/L(n=21),Ⅱ型糖尿病病人血浆中3-NT平均浓度为3.63nmol/L(n=23)。本方法灵敏度高,重现性好,适用于临床研究中大样本量的测定。

Synthesis of N,N′-Bis(2-Nitro Benzodifuroxanyl)-1,3,5-Trinitro-2,6- Diaminobenzene

N, N’-bis (2-nitro benzodifuroxanyl)-1, 3, 5-trinitro-2, 6-diaminobenzene has been synthesized from 1, 3-dianimobenzene and trinitrotrichloro benzene. The molecular structure of this compound has been determined by elemental analysis. IR. ′HNMR, and M. S. spectroscopies.

Synthesis of N,N'-bis(2,4-dinitrobenzofuroxan)-3,5-dinitro-2,6-diaminopyridine

N,N'-bis(2,4-dinitrobenzofuroxan)-3,5-dinitro-2,6-diaminopy- ridine has been synthesized from 2,6-diaminopyridine and trinitrodich- lorobenzene.For this compound,the structure has been determined by ele- mental analysis,IR,HNMR and MS spectroscopy.

Curcumin-attenuated trinitrobenzene sulphonic acid induces chronic colitis by inhibiting expression of cyclooxygenase-2

AIM： To explore the possible mechanisms of curcumin in rat colitis induced by trinitrobenzene sulfonic （TNBS） acid. METHODS： Rats with TNBS acid-induced colitis were treated with curcumin （30 mg/kg or 60 mg/kg per day ip）. Changes of body weight and histological scores as well as survival rate were evaluated. Leukocyte infiltration was detected by myeloperoxidase （MPO） activity assay. The expression of cyclooxygenase-2 （COX-2） was detected by RT-PCR and Western blot. Inflammation cytokines were determined by RT-PCR. Local concentration of prostaglandin E2 （PGE2） in colon mucosa was determined by ELISA. RESULTS： Curcumin improved survival rate and histological image, decreased the macroscopic scores and MPO activity. Also curcumin reduced the expression of COX-2 and inflammation cytokines. In addition, treatment with curcumin increased the PGE2 level. CONCLUSION： Curcumin has therapeutic effects on TNBS acid-induced colitis, the mechanisms seem to be related to COX-2 inhibition and PGE2 improvement.

The Effect of Titania Structure on Ni/TiO_2 Catalysts for p-Nitrophenol Hydrogenation

The catalytic hydrogenation of p-nitrophenol to p-aminophenol was investigated over Ni/TiO2 catalysts prepared by a liquid-phase chemical reduction method. The catalysts were characterized by inductively coupled plasma (ICP), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS) and temperature-programmed reduction (TPR). Results show that the titania structure has favorable influence on physio-chemical and catalytic properties of Ni/TiO2 catalysts. Compared to commercial Raney nickel, the catalytic activity of Ni/TiO2 catalyst is much superior, irrespective of the titania structure. The catalytic activity of anatase titania supported nickel catalyst Ni/TiO2(A) is higher than that of rutile titania supported nickel catalyst Ni/TiO2(R), possibly because the reduction of nickel oxide to metallic nickel for Ni/TiO2(A) is easier than that for Ni/TiO2(R) at similar reaction conditions.

基于BODIPY的生物硫醇荧光探针的合成和光物理性质

以4,4-二氟-8-(4-羟基苯基)-1,3,5,7-四甲基-4-硼-3a,4a-二氮杂-s-茚烯(BODIPY)和N-丁基咔唑-3-甲醛(Ⅱ)为原料合成了一种具有红光发射的荧光分子Ⅲ,其在二氯甲烷中的最大荧光发射波长为617 nm。荧光分子Ⅲ与作为生物硫醇识别基团的4-氯-7-硝基-1,2,3-苯并氧杂二唑(NBD-Cl)反应得到了一种可用于生物硫醇检测的探针BDP-NBD。由于光诱导电子转移(PET)的荧光猝灭作用,BDP-NBD发射较弱荧光,但在生物硫醇存在的情况下,PET过程受到阻止,其荧光发射强度显著增强约95倍。这种"Turn on"型荧光探针能有效检测生物硫醇,并展现出较低的检出限〔同型半胱氨酸(Hcy)6.51×10–8 mol/L;谷胱甘肽(Gsh)4.25×10–8 mol/L;半胱氨酸(Cys)4.28×10–8 mol/L〕。此外,在多种金属离子及氨基酸存在下,该探针分子仍能高效识别生物硫醇。

Juvenile ferric iron prevents microbiota dysbiosis and colitis in adult rodents

AIM: To assess whether juvenile chronic ferric iron ingestion limit colitis and dysbiosis at adulthood in rats and mice. METHODS: Two sets of experiments were designed. In the first set, recently weaned mice were either orally administered ferrous (Fe2+) iron salt or ferric (Fe3+) microencapsulated iron for 6 wk. The last week of experiments trinitrobenzene sulfonic acid (TNBS) colitis was induced. In the second set, juvenile rats received the microencapsulated ferric iron for 6 wk and were also submitted to TNBS colitis during the last week of experiments. In both sets of experiments, animals were sacrificed 7 d after TNBS instillation. Severity of the inflammation was assessed by scoring macroscopic lesions and quantifying colonic myeloperoxidase (MPO) activity. Alteration of the microflora profile was estimated usingquantitative polymerase chain reaction (qPCR) by measuring the evolution of total caecal microflora, Bacteroidetes, Firmicutes and enterobacteria. RESULTS: Neither ferrous nor ferric iron daily exposures at the juvenile period result in any effect in control animals at adulthood although ferrous iron repeated administration in infancy limited weight gain. Ferrous iron was unable to limit the experimental colitis (1.71 ± 0.27 MPO U/mg proteinvs 2.47 ± 0.22 MPO U/mg protein in colitic mice). In contrast, ferric iron significantly prevented the increase of MPO activity (1.64 ± 0.14 MPO U/mg protein) in TNBS-induced colitis. Moreover, this positive effect was observed at both the doses of ferric iron used (75 and 150 mg/kg per day po - 6 wk). In the study we also compared, in both rats and mice, the consequences of chronic repeated low level exposure to ferric iron (75 mg/kg per day po - 6 wk) on TNBS-induced colitis and its related dysbiosis. We confirmed that ferric iron limited the TNBS-induced increase of MPO activity in both the rodent species. Furthermore, we assessed the ferric iron incidence on TNBS-induced intestinal microbiota dysbiosis. At first, we needed to optimize the isolation and quantify DNA copy numbers using standard curves to perform by qPCR this interspecies comparison. Using this approach, we determined that total microflora was similar in control rats and mice and was mainly composed of Firmicutes and Bacteroidetes at a ratio of 10/1. Ferric juvenile administration did not modify the microflora profile in control animals. Total microflora numbers remained unchanged whichever experimental conditions studied. Following TNBS-induced colitis, the Firmicutes/Bacteroidetes ratio was altered resulting in a decrease of the Firmicutes numbers and an increase of the Bacteroidetes numbers typical of a gut inflammatory reaction. In parallel, the subdominant population, the enterobacteria was also increased. However, ferric iron supplementation for the juvenile period prevented the increase of Bacteroidetes and of enterobacteria numbers consecutive to the colitis in both the studied species at adulthood.CONCLUSION: Rats and mice juvenile chronic ferric iron ingestion prevents colitis and dysbiosis at adulthood as assessed by the first interspecies comparison.

COD Removal Efficiencies of Some Aromatic Compounds in Supercritical Water Oxidation

Some aromatic compounds, phenol, aniline and nitrobenzene, were oxidized in supercritical water. It was experimentally found that the chemical oxygen demand (COD) removal efficiency of these organic compounds can achieve a high level more than 90% in a short residence time at temperatures high enough. As temperature, pressure and residence time increase, the COD removal efficiencies of the organic compounds would all increase. It is also found that temperature and residence time offer greater influences on the oxidation process than pressure. The difficulty in oxidizing these three compounds is in the order of nitrobenzene ＞ aniline ＞ Phenol. In addition, it is extremely difficult to oxidize aniline and nitrobenzene to CO2 and H2O at the temperature lower than 873.15 K and 923.15 K, respectively. Only at the temperature higher than 873.15 K and 923.15 K, respectively, the COD removal efficiencies of 90% of aniline and nitrobenzene can be achieved.

Degradation of p-nitrotoluene by O_3/H_2O_2 process and oxidation mechanism

The degradation of p-nitrotoluene by O3/H2O2 process in a bubble contact column was investigated. Effects of the molar ratio of hydrogen peroxide to ozone,pH value and t-butanol on the oxidation process were discussed. It was found that the proper H2O2/O3 molar ratio for the degradation of p-nitrotoluene was around 0.6, different pH values and the presence of t-butanol highly influenced the removal efficiency of p-nitrotoluene. 5-methyl-2-nitrophenol, 2-methyl-5-nitrophenol, (4-nitrophenyl) methanol, 5-(hydroxymethyl)-2-nitro phenol, acetic acid, 2-methylpropane diacid and 2-(hydroxylmethyl)propane diacid were identified as degradation intermediates and products through GC-MS. Radical reaction mechanism and degradation pathway were proposed based on the results of experiments. It is deduced that the benzene ring of p-nitrotoluene can be only destroyed by hydroxyl radicals through a polyhydroxy intermediate pathway. Then unstable polyhydroxy intermediates can be oxidized to different acids with low molecular weight rapidly.

Lignin in Marine Environment and Its Analysis-A Review

Lignin is a group of phenolic polymers which is abundant in the woody tissues of vascular plants,and is essentially absent from all other living organisms.It has therefore been accepted as a tracer for terrestrial organic carbon(TOC) in marine environment since the 1970s.Lignin polymers are not amenable to direct chemical analysis without prior isolation.This review focused on the methods of chemical decomposition,extraction,derivatization and detection of lignin in marine environment.We described and compared several chemical decomposition methods,including nitrobenzene oxidation,alkaline cupric oxide(CuO) oxidation and thermochemolysis,and detection methods such as gas chromatography(GC),gas chromatography-mass spectrometry(GC-MS),high performance liquid chromatography(HPLC) and so on.Possible improvement of lignin analysis and the application prospects of this tracer were also discussed.

SYNTHESIS AND CHARACTERIZATION OF NOVEL SOL-GEL DOPED ORGANIC/INORGANIC HYBRID NONLINEAR OPTICAL MATERIALS

hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) materials containing NHA and DO3 were synthesized by Sol-Gel process. The preparation and properties of two NLO materials were studied and characterized by FTIR, 1H-NMR, UV-VIS, SEM, DSC and SHG measurements. The results show that the maximum doping amounts of NHA and DO3 in two doped hybrid NLO materials are 7.2(wt)% and 11.3(wt)% respectively, and the corresponding second-order NLO coefficients (d33 values) are 2.91×10 8esu and 6.14×10 8esu. Two doped NLO materials have relatively good RT stability, after 90 days at RT the d33 values can maintain about 85% of their initial values, but after 10h at 100℃ can only maintain about 50% of their initial values. In this report, the reasons for high-temperature instability of doped materials were discussed, and the possible improvements were also suggested.

Crystal Structure of 3-(4-nitro-) phenylsulfonyloxyisothiazole NO_2C_6H_4SO_3C_3H_2NS

C9H6N2O5S2 is monoclinic, space group P21/n, for 1278 observed reflections . The result indicates clearly the sul-fonylation takes place at oxygen. According to the data of bond lengths, the isothiazole ring displays aromaticity in some way.

Photochemical Degradation of Phenols in Water Using Flavin-based Photosensitizers

A slightly modified method for 10-ethyl flavin was developed in the present study. The synthetic product was characterized by nuclear magnetic resonance(NMR) and mass spectrometry, and used to catalyze the photocatalytic degradation of phenol, 2, 4-dichlorophenoxyacetic acid, p-nitrophenol, 4-chlorophenol, 4-methoxyphenol, 4-chloro-2-methyl-phenoxyacetic acid and2, 4, 5-trichloro-phenoxyacetic acid. Both HPLC(high performance liquid chromatography) and GC-MS data suggested that all phenols were degraded in the presence of either flavin at micromolar concentrations under direct sun light. A rapid breakdown of the phenols was observed. The degradation efficiency was clearly dependent on phenol type. In a decreasing order of degradation efficiency over a 2-h period, the phenols were 4-chlorophenol and 4-methoxyphenol(-80%) > phenoxyacetic acids(60%-65%) > nitrophenol and phenol(-35%).

Influence of Inorganic Salts during the Photooxidative Process of Nitrobenzene

Into the photooxidation process, several factors such as pH, time of irradiation, dose of UV light, lamp power, contaminant concentration, turbidity of the solution and the presence of salts can interfere with the photodegradation of pollutants. This research aims to evaluate the influence of salts： NaCl, MgCl2, CaCI2, BaC12, CuCl2, Na2SO4, MgSO4, MnSO4, FeSO4, CuSO4, Na3PO4, K2CrO4 and K2Cr207 in concentrations of 0.0005 M, 0.005 M and 0.05 M during photodegradation of aqueous solution of 59.5 mg/L of nitrobenzene at a pH of 2.5. It was observed that the presence of salts such as CuCI2, CuSO4, FeSO4, K2CrO4 and K2Cr207 interfere negatively in the system UV/H202 applied for degradation of nitrobenzene; possibly by oxidation of Fe2＋ to Fe3＋ and Cu＋ to Cu2＋ in the Cr case, due to the difficulty of transforming the Cr6＋ to Cr3＋ or because these solutions have color and act as radiation absorbing filter.

Treatment of O-nitro-phenol Wastewater with Magnetization-Enhanced Oxidation by NaCIO Solution

O-nitro-phenol wastewater which contains refractory organic matters can not be degraded by conventional biological methods. In this work, o-nitro-phenol wastewater was effectively treated using magnetization-enhanced oxidation by NaCIO solutions. The pollutant concentrations in wastewater were 250 mg/L o-nitro-phenol, 2,000 mg/L CODcr and 150 times color. The experimental results show that, using the method in this work, 94.4% o-nitro-phenol, 94.2% CODCr and 100% color can be removed at pH 6, 200 mg charcoal, 8 mL oxidizer, 5 min reaction time in 1000 mL wastewater. The treatment can be enhanced under magnetic field. CODCr and o-nitro-phenol removal can keep unchanged while the reaction time can be reduced to 3 min when the intensity of magnetic field was 60 mT.

Synthesis and Crystal Structure ofDinitratedioxobis(p-methyl Phenyl Butyl Sulfoxide)Uranium(Ⅵ)[UO_2(p-CH_3C_6H_4SOC_4H_9)_2(NO_3)_2]

The title compound [UO2 （p-CH3C6H4SOC4H9）2 （NO3 ）2] is triclinicwith space group P1. a=8. 651 （3）, b=9. 097（2）, c=9. 621 （2） A;a=92. 29（1）, β=95. 97（3）, r=98. 25（3）, V=744. 1（3） A3, Z=1, Mr=786.41, Dc=1. 425 g/cm3. u=5. 626 mm-1, F （000） =300. R=0. 030, Rw=0. 071 for 2917 reflectionswith I≥2（I）. Uranyl ion is coordinated to six oxygen atoms, of which two are fromtwo monodenate sulfoxides and the others from two nitrate groups. The coordinationPOlyhedron around U is a hexagonal bipyramid, the U atom is in the center of symmetry.