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1.
利用双功能螯合剂2-[(4-异硫氰基苯基)甲基]-1,4,7-三氮杂环九烷-1,4,7-三乙酸(NCS-Bz-NOTA)对Herceptin单抗表面的氨基进行修饰获得了NOTA-Herceptin,通过基质辅助激光解吸电离飞行时间质谱(MALDI-TOF)对该偶联物进行了表征.利用酶联免疫吸附测定了偶联前后Herceptin抗体效价的改变.利用新型正电子核素~(64)Cu标记,获得可用于肿瘤放射靶向精准诊疗的~(64)Cu-NOTA-Herceptin探针,其标记率为90%,放化纯度98%,比活度185 MBq/nmol.分别进行了该探针在HER2过表达胃癌细胞NCI-N87及HER2低表达胃癌细胞BGC823等肿瘤细胞中的摄取实验,测定了该探针的肿瘤特异性.建立了荷人胃癌BGC823裸鼠模型,通过微型正电子断层显像(Micro-PET)设备观察了探针在模型动物体内的代谢情况:在静脉注射7.4 MBq~(64)Cu-NOTA-Herceptin探针后,分别于4和60 h进行正电子断层显像(PET)的显像,观察到其在肿瘤部位的摄取有所富集,且随着代谢时间的延长,肝脏部位摄取得到明显降低.研究结果表明,~(64)Cu-NOTAHerceptin探针有望应用于肿瘤放射性靶向诊疗.  相似文献   

2.
石墨相氮化碳(g?C3N4)由于具有对可见光吸收范围较窄和光生载流子分离效率低等缺陷,其光解水产氢活性较差。我们采用简单的一步热共聚法,以尿素和2,4,6?三氨基嘧啶(TAPD)混合物为前驱物,制备碳自掺杂纳米片(CNNS?x,x mg代表掺入TAPD的质量)。X射线衍射(XRD)、元素分析(EA)和X射线光电子能谱(XPS)等测试结果表明,来自TAPD的嘧啶环成功引入g?C3N4共轭体系中,使所得的CNNS?x具有较窄的带隙,较快的光生载流子迁移速率,从而提高其对可见光的吸收效率和光生载流子的分离效率。得益于此,CNNS?x在可见光照射下表现出较好的光解水产氢活性。特别是CNNS?30具有最佳光解水性能,其产氢速率可达57.6μmol·h-1,是g?C3N4纳米片(CNNS)的4倍。  相似文献   

3.
刘晶  郑楚光  贾小红  徐杰英 《分析化学》2003,31(11):1360-1363
应用微波消解和电感耦合等离子体发射光谱法同时测定煤灰中的常量、少量和微量元素Si、Al、Ca、Fe、Mg、Ti、K、Ba、Mn、V、Pb、Cr、Cu和Zn。考察了微波消解体系和消解条件,0.1g煤灰用10mL硝酸和1mL氢氟酸分解,加入10mL4%硼酸溶液分解氟化物沉淀。用本法测定煤飞灰标准参考物质的结果与标准值一致。方法准确,快速,回收率为94.2%~102.3%;RSD均小于5%。  相似文献   

4.
Ultrasonic extraction was used to develop a suitable binary solvent system for the analysis of synthetic pyrethroid pesticides and mirex on soil. The analysis was carried out by gas chromatography with negative ion chemical ionization mass spectrometry (GC/MS-NICI). In the initial experiments, accurately weighed soil samples were spiked with a mixture of standard solution pyrethroids and mirex and shaken for 24?h to ensure homogeneity, then extracted with solvent. The extracts were evaporated to dryness before the volumetric internal standard was added.

The binary solvents used in this study were various mixtures of hexane?:?acetone, hexane?:?dichloromethane (DCM), isooctane?:?acetone and isooctane?:?dichloromethane, representing different classes of polarity. The recoveries of all pyrethroids and mirex were satisfactory over three solvent systems: hexane?:?acetone, hexane?:?DCM and isooctane?:?acetone, but results of isooctane?:?DCM produced low recoveries. The average recovery increased with the extraction time, but the increase was not statistically significant. A 30-min optimum extraction was deemed sufficient for recovering pyrethroids from soil. After 30?min, extraction decreased owing to the re-distribution of the analyte on the soil matrix.  相似文献   

5.
The antinociceptive activity of Flaveria trinervia extracts by tail-flicking and writhing methods was evaluated using mice. The abdominal writhing method was carried out by administering petroleum ether, chloroform and methanol extracts orally. After 1?h of incubation, 0.6% acetic acid (10?mL?kg(-1)) was administered intraperitoneally. After 5?min, each group of mice was observed for the amount of writhing for a duration of 20?min. Acetyl salicylic acid was used as the standard reference. The tail-flick method was carried out using a thermal model and the maximum possible analgesia was calculated. The LD?? values of petroleum ether, chloroform and methanol extracts were 700, 700 and 500?mg?kg?1, respectively. The methanol extract at 50?mg?kg?1 showed significant antinociceptive activity. The petroleum ether and chloroform extracts showed moderate antinociceptive activity at a dose of 70?mg?kg?1. The methanol extract showed more significant antinociceptive activity than the other extracts but was less effective than the standard. This investigation finds support for the ethnomedicinal claims of F. trinervia.  相似文献   

6.
A bare glassy carbon electrode is applied to nickel determination by adsorptive stripping voltammetry in the presence of dimethylglyoxime as a complexing agent. A procedure of nickel determination and electrode regeneration was proposed. The calibration graph for Ni(II) for an accumulation time of 120?s was linear from 2?×?10?9 to 1?×?10?7?mol?L?1. The detection limit was 8.2?×?10?10?mol?L?1. The relative standard deviation for a solution containing 2?×?10?8?mol?L?1 of Ni(II) was 4.1%. The proposed procedure was applied for Ni(II) determination in certified water reference materials.  相似文献   

7.
黄芪药渣经分级提取,再通过二乙氨乙基(DEAE)-纤维素52阴离子交换柱层析和Sephacryl S-400HR凝胶柱层析分离纯化,得到4个多糖组分AX-Ⅰ-1~AX-Ⅰ-4.对多糖AX-Ⅰ-1的理化性质和结构进行研究发现,AX-Ⅰ-1含有鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖和半乳糖(摩尔比为0.006∶14.113∶8.284∶0.116∶0.468∶1),主链由阿拉伯糖和木糖通过β-(1→2),(1→3)和(1→4)苷键组成,支链由(1→4)βArap,(1→3)βGalp和(1→2)βMan组成,非还原末端由αRhap,βGclp和βGalp组成.对多糖AX-Ⅰ-1~AX-Ⅰ-4的抗氧化研究结果表明,这4个组分对羟基自由基、超氧阴离子自由基和1,1-二苯基-2-三硝基苯肼(DPPH)自由基均有一定的清除作用;当浓度为0.1 mg/m L时,多糖AX-Ⅰ-2~AX-Ⅰ-4对超氧阴离子的清除率是阳性对照维生素C(Vc)的2倍.  相似文献   

8.
Chitosan (CS) decorated reduced graphene oxide‐Ferrocene nanocomposite (RGO?Fc?CS) was synthesized by a one‐pot reaction. In the synthesis process of RGO?Fc?CS, GO?Fc was successfully self‐assembled via the π–π interaction, which had the features of large surface area and the high load. Then GO‐Fc and CS linked via one‐pot under alkaline conditions. The FT?IR, TGA, SEM were employed to characterize the successful synthesis of RGO?Fc?CS composites. A miniature electrochemical system was fabricated by RGO?Fc?CS modified glassy carbon electrode (expressed as RGO?Fc?CS/GCE) for the sensitive detection of RhB enantiomers via DPV. Electrochemical results revealed that the RGO?Fc?CS/GCE exhibited high molecular recognition toward RhB. Due to the synergy between the RGO?Fc and CS, the RGO?Fc?CS/GCE showed a linear range of 0.001–70 μM with a LOD of 0.5 nM, indicating that RGO?Fc?CS/GCE has broad application prospects to simplify monitor RhB real‐time.  相似文献   

9.
Concentrated dilute acid hydrolysate was obtained from hot water extracts of Acer saccharum (sugar maple) and was fermented to ethanol by Pichia stipitis in a 1.3-L-benchtop bioreactor. The conditions under which the highest ethanol yield was achieved were when the air flow rate was set to 100?cm3 and the agitation rate was set to 150?rpm resulting in an overall mass transfer coefficient (K L a) of 0.108?min?1. A maximum ethanol concentration of 29.7?g/L was achieved after 120?h of fermentation; however, after 90?h of fermentation, the ethanol concentration was only slightly lower at 29.1?g/L with a yield of 0.39?g ethanol per gram of sugar consumed. Using the same air flow rate and adjusting the agitation rate resulted in lower ethanol yields of 0.25?g/g at 50?rpm and 0.30?g/g at 300?rpm. The time it takes to reach the maximum ethanol concentration was also affected by the agitation rate. The ethanol concentration continued to increase even after 130?h of fermentation when the agitation rate was set at 50?rpm, whereas the maximum ethanol concentration was reached after only 68.5?h at 300?rpm.  相似文献   

10.
A simple, efficient and economical method for the recovery of P(3HB-co-3HHx) was developed using various chemicals and parameters. The initial content of P(3HB-co-3HHx) in bacterial cells was 50?C60?wt%, whereas the monomer composition of 3HHx used in this experiments was 3?C5?mol%. It was found that sodium hydroxide (NaOH) was the most effective chemical for the recovery of biodegradable polymer. High polyhydroxyalkanoate purity and recovery yield both in the range of 80?C90?wt% were obtained when 10?C30?mg/ml of cells were incubated in NaOH at the concentration of 0.1?M for 60?C180?min at 30?°C and polished using 20?% (v/v) of ethanol.  相似文献   

11.
The synthesis of galacto-oligosaccharides (GOS) by ??-galactosidase immobilized in both polyvinyl alcohol (PVA) lenses and sol?Cgel carriers was studied and compared with the performance of the free enzyme. PVA-immobilized ??-galactosidase retained 95?% of the initial activity after seven repeated uses and retained 51?% of the initial activity after 3?months of storage, while sol?Cgel-immobilized ??-galactosidase only retained 39?% of the initial activity under storage. Lactose conversion takes place at a higher rate in the PVA-immobilized ??-galactosidase, while the lowest rate of lactose conversion was noticed with immobilized ??-galactosidase in sol?Cgel. Continuous production of GOS from either lactose or whey, with PVA-immobilized ??-galactosidase, was performed in a packed-bed reactor. A maximum GOS production of 30?% of total sugars was attained for a 40-% lactose feed solution with a feed rate of 10.8?ml/h, at pH 4.5 and 40?°C, corresponding to a productivity of 117?g/l?h. The maximum GOS productivity of 344?g/l?h was obtained at a flow rate of 28.7?ml/h. 3-OS and 4-OS were the major types of GOS formed. Conversion of whey in continuous mode resulted in GOS production of 15?% of total sugars and formation of 45?% 3-OS, 40?% 4-OS, and 15?% 5-OS.  相似文献   

12.
This study was designed to examine the chemical composition of the essential oil and the antioxidant activity of the essential oil and methanol extracts of Eucalyptus loxophleba Benth. subsp. The chemical composition of the essential oil of the leaves of E. loxophleba was analysed by GC and GC/MS. The main constituents of the oil were found to be 1,8-cineole (39.4%), methyl amyl acetate (19.8%) and aromadendrene (10%). Antioxidant activities of the samples were determined by two different test systems namely DPPH and β-carotene/linoleic acid. In the DPPH system, the highest radical-scavenging activity was shown by the polar subfraction of the methanol extract (15.2?±?1.7?μg?mL?1). Also, in the second case, the inhibition capacity (%) of the polar subfraction (94.1?±?1.3) was found to be stronger. In addition, the amounts of total phenol components in the polar subfraction (273.0?±?2.6?μg?mg?1) and nonpolar subfraction (146.3?±?2.5?μg?mg?1) were determined.  相似文献   

13.
It was found that lanthanum complex of cyclodextrin derivative (??-CD?CMAH?CLa) was a highly active ??-nucleating agent for isotactic polypropylene (iPP) in this study. The influence of the nucleating agent on mechanical properties and isothermal and nonisothermal crystallization behavior of iPP has been investigated. Results showed that ??-CD?CMAH?CLa was efficient in inducing the crystallization of iPP into ??-modification (??-iPP), with K ?? value of 0.84, while the content of nucleating agent was 0.8?wt.%. ??-iPP could form extensively in the isothermal crystallization temperature range from 110?°C to 140?°C, and the highest amount of ??-crystal content was formed at 130?°C. Besides, it can be known that the addition of ??-CD?CMAH?CLa can obviously facilitate the overall crystallization process of iPP. Under nonisothermal condition, ??-iPP formed at the suitable cooling rates, ranging from 5?°C to 10?°C/min. Furthermore, the nucleation mechanism of ??-CD?CMAH?CLa for iPP was correlated to the special configuration of ??-CD?CMAH?CLa.  相似文献   

14.
在硫磺素上分别引入给电子基氧、 硫和甲氧基, 合成出2-[4-(苯并噻唑-2-基)苯氧基]乙-1-醇(BT-OH)、 2-{[4-(苯并噻唑-2-基)苯基]硫代}乙-1-醇(BT-SH)和2-[4-(苯并噻唑-2-基)-2-甲氧基苯氧基]乙-1-醇(BT-M-OH) 3种硫磺素衍生物. 利用硫磺素衍生物作为引发剂引发D,L-丙交酯聚合, 得到3种硫磺素型聚乳酸, 再加入苯磺酸, 构建出可在室温下产生磷光的硫磺素型聚乳酸/苯磺酸体系, 实现了从荧光到磷光的可调分子发射, 其中磷光寿命最长达108.19 ms. 研究发现, 引入苯磺酸会使硫磺素型聚乳酸产生分子内电荷转移态, 质子化效应导致绿色和橘色的磷光发射.  相似文献   

15.
从云南红豆杉树皮中分离得到一个新的紫杉烷二萜化合物,用核磁共振1H谱、13C谱、DEPT、1H-1HCOSY、HMQC、HMBC谱,辅以其它谱的数据确定其为具5/7/6元环的7,9-dideacetyltaxayuntin,指定了1H和13C谱所有谱线的归属。  相似文献   

16.
An innovative protocol on accelerated in vitro propagation and acclimatisation was developed in Aloe vera L. Culture was initiated with rhizomatous stem where Murashige and Skoog (MS) medium fortified with 0.5?mg?L(-1) α-naphthalene acetic acid and 1.5?mg?L(-1) N(6)-benzylaminopurine (BAP) promoted earliest shoot induction. Maximum shoot multiplication was achieved in MS medium supplemented with 2.5?mg?L(-1)BAP. The best in vitro rooting was observed in the MS medium with 0.5?mg?L(-1) indole-3-acetic acid plus 2?g?L(-1) activated charcoal. The simple acclimatisation process, primarily with a combination of sand and soil (1?:?1 v/v) and finally with a blend of sand, soil and farm yard manure (2?:?1?:?1 v/v), ensured a 98% survival rate. Overall, 192 true-to-type plantlets were achieved from a single explant within 85 days. Morphologically, in vitro generated plants performed better than conventionally propagated plants; nevertheless the similarity in aloin content, gel content and superoxide dismutase activity was corroborated.  相似文献   

17.
Ru(Ⅲ)、Rh(Ⅲ)、Pd(Ⅱ)离子与ct-DNA的相互作用研究   总被引:7,自引:0,他引:7       下载免费PDF全文
本文以中药小檗碱作为分子探针,在0.01mol·L-1醋酸-醋酸钠缓冲体系中,用紫外-可见吸收及荧光光谱法研究了Ru(Ⅲ)、Rh(Ⅲ)、Pd(Ⅱ)三种贵金属离子与DNA的键合相互作用。实验发现Ru(Ⅲ)离子对小檗碱-DNA二元体系的荧光有较强的猝灭作用;而Rh(Ⅲ)、Pd(Ⅱ)两种离子则对该二元体系产生显著的荧光敏化作用。考察了EDTA对贵金属离子、小檗碱及DNA三元混合体系的荧光光谱的影响,初步探讨了贵金属离子与DNA可能的键合机理。  相似文献   

18.
The insecticidal activity of Piper nigrum fruit-derived piperidine alkaloid (piperine) and N-isobutylamide alkaloids (pellitorine, guineensine, pipercide and retrofractamide A) against female adults of Culex pipiens pallens and Aedes aegypti was examined. On the basis of 24-h LD(50) values, the compound most toxic to female C. pipiens pallens was pellitorine (0.4?μg/♀) followed by guineensine (1.9?μg/♀), retrofractamide A (2.4?μg/♀) and pipercide (3.2?μg/♀). LD(50) value of chlorpyrifos was 0.03?μg/♀. Against female A. aegypti, the insecticidal activity was more pronounced in pellitorine (0.17?μg/♀) than in retrofractamide A (1.5?μg/♀), guineensine (1.7?μg/♀), and pipercide (2.0?μg/♀). LD(50) value of chlorpyrifos was 0.0014?μg/♀.  相似文献   

19.
The kinetics of formation of the 1?:?1 complex of chromium(III) with 1,3-propanediamine-N,N′-diacetate-N,N′-di-3-propionate (1,3-pddadp) were followed spectrophotometrically at λ max?=?557?nm. The reaction was first-order in chromium(III). Increasing the 1,3-pddadp concentration from 2.2?×?10?2 to 0.11?mol?dm?3 accelerated the reaction rate. Increasing the hydrogen ion concentration from 1.995?×?10?5 to 6.31?×?10?4 mol?dm?3 retarded the reaction rate. The reaction rate was also retarded by increasing ionic strength and dielectric constant of the reaction medium. A mechanism was suggested to account for the results obtained which involves ion-pair formation between the various reactants. Values of 22?kJ?mol?1 and ?115?J?K?1 mol?1 were obtained for the energy and the entropy of activation, respectively, which indicate an associative mechanism. The logarithm of the formation constant of the 1?:?1 complex formed was 11.3.  相似文献   

20.
The dehydrocoupling/dehydrogenation behavior of primary arylamine-borane adducts ArNH(2)?BH(3) (3?a-c; Ar = a: Ph, b: p-MeOC(6)H(4), c: p-CF(3)C(6)H(4)) has been studied in detail both in solution at ambient temperature as well as in the solid state at ambient or elevated temperatures. The presence of a metal catalyst was found to be unnecessary for the release of H(2). From reactions of 3?a,b in concentrated solutions in THF at 22?°C over 24?h cyclotriborazanes (ArNH-BH(2))(3) (7?a,b) were isolated as THF adducts, 7?a,b?THF, or solvent-free 7?a, which could not be obtained via heating of 3?a-c in the melt. The μ-(anilino)diborane [H(2)B(μ-PhNH)(μ-H)BH(2)] (4?a) was observed in the reaction of 3?a with BH(3)?THF and was characterized in situ. The reaction of 3?a with PhNH(2) (2?a) was found to provide a new, convenient method for the preparation of dianilinoborane (PhNH)(2)BH (5?a), which has potential generality. This observation, together with further studies of reactions of 4?a, 5?a, and 7?a,b, provided insight into the mechanism of the catalyst-free ambient temperature dehydrocoupling of 3?a-c in solution. For example, the reaction of 4?a with 5?a yields 6?a and 7?a. It was found that borazines (ArN-BH)(3) (6?a-c) are not simply formed via dehydrogenation of cyclotriborazanes 7?a-c in solution. The transformation of 7?a to 6?a is slowly induced by 5?a and proceeds via regeneration of 3?a. The adducts 3?a-c also underwent rapid dehydrocoupling in the solid state at elevated temperatures and even very slowly at ambient temperature. From aniline-borane derivative 3?c, the linear iminoborane oligomer (p-CF(3)C(6)H(4))N[BH-NH(p-CF(3)C(6)H(4))](2) (11) was obtained. The single-crystal X-ray structures of 3?a-c, 5?a, 7?a, 7?b?THF, and 11 are discussed.  相似文献   

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