RP-HPLC测定普瑞巴林胶囊

建立以反相高效液相色谱法测定普瑞巴林胶囊含量的方法。色谱柱为Waters Sunfire C₁₈（4.6mm×150mm,5μm）,流动相为磷酸盐缓冲液-乙腈（95:5,V/V）,柱温30℃,流速1.0mL·min^-1,检测波长为205nm。普瑞巴林在0.2147—2.1466mg·mL^-1浓度范围内线性关系良好,回归方程为:Y=1492321.09X+1516.89（r=0.9999）;平均回收率为100.2%,RSD=1.26%（n=9）。该法准确、简便、快速、可靠,能有效控制普瑞巴林胶囊的质量。     

A new diketopiperazine derivative from a deep sea-derived Streptomyces sp. SCSIO 04496

A new diketopiperazine (DKP) derivative, (6R,3Z)-3-benzylidene-6-isobutyl-1-methyl piperazine-2,5-dione (1), as well as five known DKPs 2–6 was isolated from a deep sea-derived Streptomyces sp. SCSIO 04496. The structure of 1 was elucidated using a combination of 1D and 2D NMR, HR-ESI-MS and chiral-phase HPLC techniques. Compounds 1–6 did not show cytotoxic activity at a concentration of 100 μM in bioactivity assay.     

A characterization of maximum norms of commutators of positive contractions

In this note, we give a characterization of a pair (A,B) of positive contractions with commutator AB−BA of maximum possible norm. A necessary and sufficient condition is that either or its complex conjugate is in the closure of the numerical range of AB.     

The expression patterns of vascular endothelial growth factor and thrombospondin 2 after corneal alkali burn

The aim of the investigation was to explore the expression patterns of VEGF and TSP2 after corneal alkali burn in vivo. After the model of corneal alkali burn was established in mice, the expression levels of VEGF and TSP2 were determined by immunohistochemistry (IHC), RT-PCR, image analysis and statistical evaluation. Compared with control group, the expression level of VEGF increased significantly at 6h after alkali burn and reached its maximum at 12h. Then, it increased again till the second peak appeared at 96h and 192h. The VEGF-positive reaction mainly gathered in the stroma of cornea. On the other hand, the expression of TSP2 enhanced at 3h and attained two peaks at 6h and 96h, respectively, with the process of wound healing. TSP2 was expressed mainly in the base of epithelial layer. The expression patterns of VEGF and TSP2 reflect the complicated interaction with many factors including promoted and inhibited vascularization in vivo. Moreover, it might provide a novel method for controlling vascular hyperplasia in future clinical work according to the data of VEGF and TSP2.     

反相高效液相色谱荧光检测法测定新型咀嚼胶片剂中右美沙芬的血浆浓度

建立反相高效液相色谱荧光检测法测定口服新型咀嚼胶片剂后血浆中右美沙芬浓度的方法。采用Hanbon C18（4.6mm×250mm,5μm）色谱柱,以乙腈-水-磷酸-三乙胺（35∶65∶0.14∶0.10,V/V/V/V）为流动相,在流速0.6mL.min-1,进样量50μL,柱温30℃,荧光激发波长（Ex）和发射波长（Em）分别为280nm和320nm条件下,测定咀嚼胶片剂中右美沙芬的兔血药浓度。药物与杂质分离效果良好、线性范围为1—1000ng.mL-1,相关系数为0.9996。方法回收率和提取回收率分别为110.0%和83.9%。当S/N=3时,右美沙芬最低检出浓度可达1ng.mL-1。本方法准确、灵敏,可满足血药浓度检测和研究药代动力学行为的需要。     

巫溪南门湾危岩体稳定性分区研究

危岩体是影响人类生命财产安全与工程活动的自然地质灾害之一。对危岩体的勘察、稳定性评价与防治是地质灾害防治的研究难题。受危岩体复杂地质特征影响,南门湾危岩体由20余个危岩块体组成,其防治设计存在一定工程风险。本文通过分析岩体裂隙系统发育状况,在W6危岩单体稳定性研究的基础上,建立了赤平投影法评价危岩体稳定性的判断标准与南门湾危岩体的稳定性分区,提出了对应的防治措施建议。本文的稳定性研究具有一定的理论意义,对该危岩体的防治工程具有指导意义。     

PVA/DTC纳米纤维的制备及对铅离子的吸附行为

通过高压静电纺丝技术制备了聚乙烯醇/聚乙烯亚胺(PVA/PEI)纳米纤维膜, 对纤维膜进行功能化使其转化为对重金属离子具有高络合能力的聚乙烯醇/二硫代氨基甲酸盐功能化聚乙烯亚胺(PVA/DTC)纳米纤维膜. 研究了PVA/PEI纳米纤维膜的交联和功能化以及PVA/DTC纤维膜对铅离子的吸附行为. 结果表明, 高压静电纺丝法可制备出纤维直径分布均匀、 形貌良好的纳米纤维膜, 且交联、 功能化后仍能保持蓬松纳米纤维状的网状结构. PVA/DTC纳米纤维膜对铅离子吸附速率快, 吸附量容量高, 且具有良好的再生吸附能力, 是一种潜在的重金属离子高效吸附材料.     

Phase Correction-Adaptive Line Enhancement for Noise Reduction of Low-Field NMR

The amplitude of low-field nuclear magnetic resonance (NMR) is weak, and the echo is buried in the noise. The reduction of noise is critical to accurately extract echo amplitude. Phase correction-adaptive line enhancement (PC-ALE) is proposed to noise suppression based on the principle of ALE and NMR spin-echo characteristics. The echo amplitude is calculated after two-stage processes; phase shift from time-delay and filter tap would be compensated effectively in frequency domain. Simulation and experiments show that PC-ALE has prominent performance on noise suppression, envelope recovery, as well as the correction of the phase shift. The amplitude from the method of sample average nearby the middle of the echo is more accurate than the maximum peak when the PC-ALE is applied to noise suppression of spin-echo.     

重庆地区食盐加碘含量下调的可行性研究

为探讨重庆市食盐加碘含量下调的可行性,分析比较了重庆市碘盐和碘缺乏病监测结果(儿童甲状腺肿大率、智商、尿碘、家庭食用碘盐)。结果表明,碘盐含量稳定,全民食盐加碘防治碘缺乏病的措施成功,但尿碘水平高于适宜水平,甲肿率居高不下,可能存在补碘过量,引起高碘性甲状腺肿大。为有效控制甲肿率和尿碘水平,建议下调食盐加碘含量。     

Nanosilver-doped DNA polyion complex membrane for electrochemical immunoassay of carcinoembryonic antigen using nanogold-labeled secondary antibodies

A simple and sensitive electrochemical immunoassay protocol was developed for the detection of carcinoembryonic antigen (CEA) using nanosilver-doped DNA polyion complex membrane (PIC) as sensing interface. To construct such an immunosensor, double-stranded DNA was initially assembled onto the surface of thionine/Nafion-modified screen-printed carbon electrode to adsorb silver ions with positive charges, then silver ions were reduced to nanosilver particles with the aid of NaBH₄, and then anti-CEA antibodies were immobilized on the nanosilver surface. Gold nanoparticles conjugated with horseradish peroxidase-labeled anti-CEA were employed as signal antibodies for the detection of CEA with a sandwich-type assay format. Under optimal conditions, the immunosensor exhibited a dynamic range of 0.03-32 ng mL⁻¹ with a low detection limit of 10 pg mL⁻¹ CEA. Intra- and inter-assay imprecision (CVs) were <9.5% and 6.5%, respectively. The response could remain 90.1% of the original current at 30th day. 50 real samples were evaluated using the immunosensor and the enzyme-linked immunosorbent assay, respectively, and received in accordance with those two methods.