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1.
The thermal behavior and kinetic parameters of the exothermic decomposition reaction of N-methyl-N-nitro-2,2,2-trinitroethanamine in a temperature-programmed mode have been investigated by means of differential scanning calorimetry (DSC).The kinetic equation of the exothermic decomposition process of the compound is proposed. The values of the apparent activation energy (Ea), pre-exponential factor (A), entropy of activation (ΔS^≠ ), enthalpy of activation (ΔH^≠ ), and free energy of activation (ΔG^≠ ) of this reaction and the critical temperature of thermal explosion of the compound are reported. Information is obtained on the mechanism of the initial stage of the thermal decomposition of the compound.  相似文献   

2.
The thermal behavior, mechanism and kinetic parameters of the exothermic first-stage decomposition of the title compound in a temperature-programmed mode were investigated by means of DSC, TG-DTG and IR. The reaction mechanism was proposed. The kinetic model function in differential form, apparent activation energy(Ea) and pre-exponential factor(A) of this reaction are (3/2)(1-a)[-ln(1-a)]1/3, 185.52 kJ/mol and 1017.78 s-1, respectively. The critical temperature of the thermal explosion of the compound is 201.30 ℃. The values of ΔS≠, ΔH≠ and ΔG≠ of this reaction are 72.46 J/(mol · K), 175.1 kJ/mol and 141.50 kJ/mol, respectively.  相似文献   

3.
5-Acyl-2-furancarboxaldehydes2arelmpol-tantIntermedlateslforsynthesizingnaturallyoccuTTingfuranoldfattyacidswhichhaveantloxldanteffectsandantlneoplastlcactlvltlesInbiologicalsystems-.Nakayamaela尸reportedsuccessfulhalodesllylatlonofethyls-trlm...  相似文献   

4.
The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the disinfection of water polluted by microcystins. The influence factors such as H2O2, pH and UV light intensities were investigated respectively. Degradation of microcystin-RR (MC-RR) could be fitted by either the pseudo-first-order or second-order rate equations. This homogenous system could significantly enhance the degradation rate due to the synergetic effect between UV and H2O2. The degradation mainly followed the mechanism of direct photolysis and .OH oxidation reactions. Experimental results showed that 94.83% of MC-RR was removed under optimal experimental conditions and the UV/H2O2 system provided an alternative to promote the removal of microcystins in drinking water supplies.  相似文献   

5.
PaclitaxelisapromisinganticancerdmgusedfortreatInentofbreastandovarycancer.lSARstUdieshaverevealedthatthefunctionalitiesatthes0uthemhemisphereofthemoleculeareimPortantf0rantitUmoractivity',butl-hydroXyisstillablackb0x.TwogrouPs"shaveindePendentlyremovedC-l0oxygenfunctionalityusingsamariumdiiodide,anelectrontransferlanthanidereagent,stedingfr0mbaccatinIIIorfr0mpaclitaxel.Wereasonedthatthel-OHofbaccatinlllmightberemovedbyfirstconvertingC-2benzoateint0aketone,whichwillreducethesterichindran…  相似文献   

6.
IntroductionChlordiazepoxide (7 chloro 2 methylamino 5 phenyl 3H 1,4 benzodiazepine 4 oxide)showingpowerfulan tianxietyeffecthasbeenwidelyusedasapsychotherapeu ticdrug .Consequently ,theneedaroseforsensitiveandrapiddeterminationofchlordiazepoxideinblood ,urinean…  相似文献   

7.
For the first time the isomerization of 1,3,2-diazaphospholidine-2-sclenide dervatives in refluxing benzene in the presence of trace water was observed. The structures of isomerized products were determined by IR, ^1H NMR,^31P NMR, elemental analysis and X-ray crystallography. The mechanism of isomerization was also proposed.  相似文献   

8.
1 INTRODUCTION Recently coinage metal complexes of poly- dentate phosphines are of great interest owing to the applications in diverse areas such as supramolecular design, photophysics and catalysis[1~4]. It is well- known that the binuclear coinage metal complexes of diphosphine [M2(diphosphine)2(MeCN)2]2+ (M = Cu, Ag, Au)[5~16] are excellent precursors for the design of polynuclear or polymeric materials with desired properties due to the easy substitution of weakly coordinated ac…  相似文献   

9.
The photosystem Ⅱ (PS Ⅱ ) particles were purified by means of nano-anatase TiO2 treatment of spinach and studied by spectroscopy. The results show that the electron transport and the oxygen-evolving rate of PS Ⅱ are accelerated after it has been treated with nano-anatase TiO2; the UV-Vis absorption spectrum of PS Ⅱ particles is increased; the red shift of fluorescence emission peak of PS Ⅱ is 2 nm; the peak intensity is decreased; the PS Ⅱ signal Ⅱ s of low temperature electron paramagnetic resonanace(EPR) spectrum is intensified under light, and the PS Ⅱ circular dichroism(CD) spectrum is similar to that of control. It is suggested that nano-anatase TiO2 might bind to the PS Ⅱ reaction center complex and intensify the function of the PS Ⅱ electron donor, however, nano-anatase TiO2 treatment does not change the configuration of the PS Ⅱ reaction center complex.  相似文献   

10.
2-Amino substituted benzothiazole 4a—4l and p-acetamidobenzenesulfonyl chloride 2 were used to prepare 2-(p-aminophenylsulfonamido) substituted benzothiazole 6a—6l using mixture of pyridine and acetic anhydride which formed an electrophilic complex (N-acetyl pyridinium) to facilitate condensation to give desired product by removal of HCl. 2-{p-[(3-Carboxypyrid-2-yl)amino]phenylsulfonamido}benzothiazoles 8a—8l were synthesized from 2-chloropyridine-3-carboxylic acid 7 and 6a—6l in 2-ethoxy ethanol using Cu-powder and K2CO3. Acid chlorides 9a—9l were condensed with 2-hydroxyethyl piperazine 10 and 2,3-dichloropiperazine 11 for amide derivatives 2-(p-((3-(4-(2-hydroxyethyl)piperazin-1-ylcarbonyl)pyrid-2-yl)amino)phenylsulfonamido)benzothiazoles 12a—12l and 2-{p-[3-(2,3-dichloropiperazin-1-ylcarbonyl)pyrid-2-ylamino]phenylsulfonamido}benzothiazoles 13a—13l respectively. The structures of the new compounds have been established on the basis of their chemical analysis and spectral data (IR, 1H NMR and mass). All the compounds have been screened for their antibacterial and antifungal activities.  相似文献   

11.
The study aimed to evaluate the effects of deoxycholic acid (DCA) on human gastric carcinoma cell lines and to explore its mechanisms. In the present study, effects of DCA on SGC-7901 cell growth, cell cycle, and apoptosis were investigated by MTT assay, inverted microscopy, fluorescence microscopy, PI single- and FITC/PI double-staining flow cytometry, and western blotting. The study have revealed that DCA significantly inhibited the growth of SGC-7901 cells in a dose- and time-dependent manner and arrested cell cycle at G0/G1 phase. SGC-7901 cells showed typical apoptotic morphological changes after treated with DCA for 48 h. The intensity of typical apoptosis pattern- “ladders” formed by DNA in fragments of multiples of 200 base pairs was also observed. Apoptosis of SGC-7901 cells induced by DCA were associated with collapse of the mitochondrial membrane potential. DCA treatment could also increase the ratio of Bax to Bcl-2 in SGC-7901 cells. Meanwhile, the expression of p53, cyclinD1, and c-Myc were changed after DCA treatment. These results suggest that DCA induces apoptosis of gastric carcinoma cells through an intrinsic mitochondrial-dependent pathway, and the increase in the Bax/Bcl-2 ratio and collapse of the mitochondrial membrane potential may play important roles in DCA-induced apoptosis of gastric carcinoma cells.  相似文献   

12.
利用微流控芯片易于模拟体内生理环境、 流体控制精确及易于集成等优势, 将基于扩散原理的浓度梯度形成结构与经典的圣诞树形浓度梯度发生器相集成, 建立了在垂直和水平方向上形成连续、 双向浓度梯度的微流控芯片系统, 采用该系统对不同类型细胞(HEK-293, MCF-7, SGC-7901)的侵袭力进行了定量分析; 通过在垂直方向上施加血清浓度梯度, 在水平方向上施加抗肿瘤药物十字孢碱浓度梯度, 分析了在连续药物浓度作用下的人胃癌SGC-7901细胞侵袭能力被抑制的情况, 同时观察并定量评价了伴随细胞侵袭力变化过程中细胞增殖能力受抑制的情况. 研究结果表明, 该系统可形成稳定的双向物质浓度梯度; 在血清浓度梯度存在情况下, 伴随十字孢碱浓度梯度的升高, 肿瘤细胞侵袭(P<0.0001)和增殖能力(P<0.001)均呈现浓度依赖性的连续降低. 建立的双向浓度梯度微流控芯片系统可用于评价复杂环境对细胞的多重影响, 也为研究细胞间相互作用、 多种药物联用及药物筛选等提供了良好的研究平台.  相似文献   

13.
Recent observations indicate that the resistance of apoptosis is an important process of tumor metastasis and metastases are the cause of 90% of human cancer death. Etoposide, a semisynthetic derivative of the podophyllotoxins, is a clinically used anti-cancer reagent, but the effects of it on metastatic gastric carcinoma cells are totally unknown. In this study, etoposide induced apoptotic cell death in human gastric adenocarcinoma cell line SGC-7901, derived from metastatic lymph nodes, as evidenced by the analysis of DNA fragmentation, apoptotic body formation, caspase activation, and apoptosis specific changes in cell morphology is demonstrated. The depolarization of mitochondrial membrane and the release of cytochrome c were most early events in etoposide treated SGC-7901 cells, and were followed by caspase-3 activation and PARP cleavage. Caspase-8 activation was not detected under the same condition. Thus, it was proposed that etoposide induces caspase-associated apoptotic cell death in human metastatic gastric carcinoma, which is initiated by mitochondrial cytochrome c release.  相似文献   

14.
以2,6-二氯嘌呤为原料,对其2-位和6-位进行结构修饰,合成了8个新型2,6-二胺嘌呤类衍生物(3a~3h),其结构经~1H NMR,IR和MS(ESI)表征。采用MTT法研究了3a~3h对人胃癌SGC-7901细胞的体外抗肿瘤活性。结果表明:3a,3b,3c,3g具有良好的抗肿瘤活性,其中3c(IC5065.01μmol·L~(-1))对人胃癌细胞SGC-7901的抑制作用最强。  相似文献   

15.
光激发纳米TiO2对胃癌SGC-7901细胞的杀伤作用   总被引:1,自引:0,他引:1  
探讨了光激发纳米TiO2对胃癌SGC-7901细胞的杀伤作用, 考察了在不同纳米TiO2浓度及不同光照时间下纳米TiO2的抑瘤效果, 并探讨了抑瘤机制. 结果表明, 光激发纳米TiO2对胃癌SGC-7901细胞具有明显的抑制作用, 其过程类似一级反应的动力学规律; 当纳米TiO2浓度为300 μg/mL时, 对胃癌SGC-7901细胞表现出较强的杀伤效果, 其主要表现形式有两种, 即细胞坏死和细胞凋亡, 是由光激发条件下, 纳米TiO2表面产生的活性氧组分对肿瘤细胞的有效杀伤所致.  相似文献   

16.
A dioxovanadium(V) complex, [VO2(moptpy)](ClO4) (1, moptpy = 4′-(3-methoxyphenyl)2,2′:6′2″-terpyridine), was synthesized and characterized by elemental analysis, ESI-MS, UV–vis, IR, and 1H, 13C, and 51V NMR. The cytotoxicity in vitro of 1 was evaluated against cancer cell lines HepG-2 (hepatocellular carcinoma), SGC-7901 (gastric carcinoma), SiHa (cervical cancer), BEL-7402 (hepatocellular), and rat PC-12 (pheochromocytoma) by the MTT method. The results demonstrated that 1 exhibits superior anticancer activity in vitro with much lower values of 50% inhibitive concentration (IC50) against the selected cell lines than cisplatin, and 1 shows the highest cytotoxic activity toward SGC-7901 cells (IC50 = 1.3 ± 0.1 μM) among the selected cell lines. A series of cellular morphological and staining experiments were carried out, and the results indicated that 1 can effectively induce apoptosis of SGC-7901 cells through a ROS-mediated mitochondrial dysfunction pathway. In addition, cellular incorporation and cell cycle analysis were also performed, and it was concluded from the experimental observations that 1 can efficiently enter into the cell nuclei, and the complex inhibits cell growth in SGC-7901 cell at G0/G1 phase.  相似文献   

17.
Two novel alkaloids, saprosmine A (1) and saprosmine B (2), were isolated from the stem of Saprosma hainanense MERR., along with five known alkaloids: marcanine A (3); cleistopholine (4); 4-methoxycarbonyl-5,10-benzogquinolinequinone (5); liriodenine (6); and quinoline (7). The chemical structures were established on the basis of extensive spectroscopic (IR, 1D-NMR, 2D-NMR, MS) data analysis and by comparison with spectroscopic data reported in the literature. Compounds 1 to 6 were evaluated for in vitro cytotoxic activities against the SPC-A-1 (human lung cancer), BEL-7402 (human hepatocellular carcinoma), SGC-7901 (human gastric cancer), and K-562 (human myelogenous leukaemia) cancer cell lines. Compounds 1 and 2 exhibited weak cytotoxic activities against K-562 cells. Compounds 3 and 5 showed cytotoxic activities against all four cancer cell lines.  相似文献   

18.
Thalictrum fortunei S. Moore, a perennial plant distributed in the southeastern part of China, has been used in Traditional Chinese Medicine for thousands of years for its antitumor, antibacterial and immunoregulatory effects. In order to investigate the active components and the mechanism of the anti-tumor effects of Thalictrum fortunei, the growth inhibitory effects of eight triterpenoids isolated from the aerial parts of the plant on tumor cell lines were examined by 3-(4,5)-dimethylthiazoy1-3,5-diphenyltetrazolium bromide (MTT) assay. The MTT-assay results showed that the inhibitory activity of 3-O-β-D-glucopyranosyl-(1→4)-β-D-fucopyranosyl(22S,24Z)-cycloart-24-en-3β,22,26-triol 26-O-β-D-glucopyranoside (1) was stronger than that of the other seven tested triterpenoids on human hepatoma Bel-7402 cell line (Bel-7402), human colon lovo cells (LoVo), human non-small cells lung cancer NCIH-460 cells (NCIH-460) and human gastric carcinoma SGC-7901 cells (SGC-7901) after 48 h treatment in vitro, with the IC(50) values of 66.4, 84.8, 73.5, 89.6 μM, respectively. Moreover, the antitumor mechanism of compound 1 on Bel-7402 cell was explored through nucleus dyeing, fluorescence assay, flow cytometry and western blot. The flow cytometric analysis results revealed that compound 1 caused apoptosis and mitochondrial membrane potential (MMP) loss in Bel-7402 cells. A fluorescence assay indicated that intracellular reactive oxygen species (ROS) were markedly provoked by compound 1 treatment compared to control cells. Immunoblot results showed that compound 1 significantly increased the expression levels of cleaved caspase-3, P53 and Bax protein, and decreased the expression level of Bcl-2 protein. These findings indicate that compound 1 inhibits the growth activity of tumor cells, probably through the P53 protein-induced apoptosis pathway.  相似文献   

19.
Two Au(III) complexes of the type [Au(en)2]Cl3 (2a) and [Au(N-pr-en)2]Cl3 (3a) were synthesized by reacting Auric acid (HAuCl(4)·3H2O) with 2 equiv. ethylenediamine (en) or N-alkyl substituted ethylenediamine ligands. This metallodrug was characterized by various analytical and spectroscopic techniques such as elemental analysis, UV-Vis, Far-IR, 1H NMR and solution 13C as well as solid 13C and 15N NMR. Potentiality of [Au(en)2]Cl3 and [Au(N-pr-en)2]Cl3 as an anti-cancer agent were investigated by measuring some relevant physicochemical and biochemical properties such as stability of Au-N bonds by vibrational stretching from Far IR as well as cytotoxicity and stomach cancer cell inhibiting effect, respectively. The solid-state 15N NMR chemical shift shows that the ligand is strongly bound to gold(III) centre via N atoms. The computational study of 2a shows that the gold coordination sphere adopts distorted square planar geometry with bidentate ethylenediamine ligands acting as a tetradentate chelate. While stable in the solution state, the in vitro biological studies performed with these compounds 2a in solution showed higher activity towards the inhibitory effects of the human cancer cell lines such as prostate cancer (PC-3) and gastric carcinoma (SGC-7901) than that of the N-substituted gold(III) complex (3a). Cytotoxicity of the new compounds has also been estimated in PC-3 and SGC-7901 cells.  相似文献   

20.
Bispecific antibodies were constructed using genetically encoded unnatural amino acids with orthogonal chemical reactivity. A two-step process afforded homogeneous products in excellent yield. Using this approach, we synthesized an anti-HER2/anti-CD3 bispecific antibody, which efficiently cross-linked HER2+ cells and CD3+ cells. In vitro effector-cell mediated cytotoxicity was observed at picomolar concentrations.  相似文献   

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