Formulation and comparative characterization of chitosan, gelatin, and chitosan-gelatin-coated liposomes of CPT-11-HCl

Liposomes containing phosphatidylcholine and cholesterol (uncoated) and coated by chitosan, gelatin, and combination of chitosan and gelatin were prepared by the modified ethanol injection method. The aim of this work was to formulate and characterize liposomes of camptothecin (CPT)-11-HCl (Irinotecan HCl) containing chitosan, gelatin, and both polymers as coating materials; and also to increase its circulation longevity when compared with the free drug while maintaining the agent in its active lactone form. Size, shape, zeta potential, encapsulation efficiency, stability study, in vitro, and in vivo release study were used for characterization of liposomes. The size of liposomes was in the order of uncoated < chitosan coated < gelatin coated < combination of chitosan and gelatin coated. The zeta potential of liposomes was in the order of combination of chitosan and gelatin coated > chitosan coated > gelatin coated > uncoated. The formulations showed the long-term stability. The encapsulation efficiency of liposomes was in order of combination of chitosan and gelatin coated > gelatin coated > chitosan coated > uncoated. The in vitro and in vivo release of drug was observed in the order of combination chitosan and gelatin coated > gelatin coated > chitosan coated > uncoated.     

Design and Prototype of a Performance Tool Interface for OpenMP

This paper proposes a performance tools interface for OpenMP, similar in spirit to the MPI profiling interface in its intent to define a clear and portable API that makes OpenMP execution events visible to runtime performance tools. We present our design using a source-level instrumentation approach based on OpenMP directive rewriting. Rules to instrument each directive and their combination are applied to generate calls to the interface consistent with directive semantics and to pass context information (e.g., source code locations) in a portable and efficient way. Our proposed OpenMP performance API further allows user functions and arbitrary code regions to be marked and performance measurement to be controlled using new OpenMP directives. To prototype the proposed OpenMP performance interface, we have developed compatible performance libraries for the Expert automatic event trace analyzer [17, 18] and the TAU performance analysis framework [13]. The directive instrumentation transformations we define are implemented in a source-to-source translation tool called OPARI. Application examples are presented for both Expert and TAU to show the OpenMP performance interface and OPARI instrumentation tool in operation. When used together with the MPI profiling interface (as the examples also demonstrate), our proposed approach provides a portable and robust solution to performance analysis of OpenMP and mixed-mode (OpenMP+MPI) applications.     

Formulation and Comparative Characterization of Chitosan,Gelatin, and Chitosan–Gelatin-Coated Liposomes of CPT-11–HCl

Liposomes containing phosphatidylcholine and cholesterol (uncoated) and coated by chitosan, gelatin, and combination of chitosan and gelatin were prepared by the modified ethanol injection method. The aim of this work was to formulate and characterize liposomes of camptothecin (CPT)-11–HCl (Irinotecan HCl) containing chitosan, gelatin, and both polymers as coating materials; and also to increase its circulation longevity when compared with the free drug while maintaining the agent in its active lactone form. Size, shape, zeta potential, encapsulation efficiency, stability study, in vitro, and in vivo release study were used for characterization of liposomes. The size of liposomes was in the order of uncoated?<?chitosan coated?<?gelatin coated?<?combination of chitosan and gelatin coated. The zeta potential of liposomes was in the order of combination of chitosan and gelatin coated?>?chitosan coated?>?gelatin coated?>?uncoated. The formulations showed the long-term stability. The encapsulation efficiency of liposomes was in order of combination of chitosan and gelatin coated?>?gelatin coated?>?chitosan coated?>?uncoated. The in vitro and in vivo release of drug was observed in the order of combination chitosan and gelatin coated?>?gelatin coated?>?chitosan coated?>?uncoated.     

Catalytic HTL-derived biochar and sol-gel synthesized (Mn,Ti)-oxides for asymmetric supercapacitors

In this study, hydrothermal liquefaction (HTL)-derived biochar is investigated as electrode material with sol-gel-derived (Mn, Ti)-oxide electrode for asymmetric supercapacitor. To generate biochar, pinewood flour was used as an example biomass feedstock for HTL, which was carried out at 300°C and 1500 psi for 1 hour in the absence and presence of the Ni-nitrate (Ni[NO₃]₂.6H₂O) catalyst. After HTL, different products were analyzed by TOC analyzer, HPLC, and GCMS, and mass yield/carbon balance was determined. Solid residue recovered after HTL or catalytic HTL (CHTL) was thermally treated at 400°C for 2 hours to obtain biochar, which was characterized using BET surface area analyzer and SEM/EDX, and utilized as one of the electrodes. To fabricate asymmetric supercapacitor (ASC), (Mn,Ti)-oxide electrode material was synthesized using sol-gel technique with Mn:Ti precursor ratio of 30:70 wt%. As-synthesized gels were aged, dried, and calcined with a 2-step heating process (step-1: heating to 500°C and cooling to 50°C, and step-2: heating to 1000°C with soak time of 2 hours and cooling to 50°C), which were characterized by powdered X-ray diffraction and BET analysis. Asymmetric supercapacitors were fabricated with HTL/CHTL derived biochar/(Mn,Ti)-oxide electrodes and KOH electrolyte, and tested with cyclic voltammetry to determine specific capacitance. ASC fabricated with CHTL-derived biochar electrode showed a higher specific capacitance of 187 F/g.     

Synchronous steady state response of an overhung rotor with squeeze film damping

An analytical method is developed for treatment of a typical system in which the outrigger bearing of an overhung rotor is provided with a squeeze film damper supported in a flexible casing. The rotor and stator of multiple degrees-of-freedom are handled with convenience by a “polar receptance matrix” method. A characteristic equation is derived which governs rotor-stator interaction either with dry contact or through a squeeze film damper. For the nonlinear squeeze film action solutions based on “mobility” information of a dynamically loaded journal bearing are obtained facilitating a general approach. A computer programme is written in Fortran for steady state response of the system in terms of whirl, position and force vectors, trial runs of which indicate complex behaviour of a squeeze film damped system.     

2'-脱氧核糖胞苷的合成工艺

本文报道了2''-脱氧核糖胞苷的一条工业化生产的路线。该工艺路线以α-D-2-脱氧核糖和尿嘧啶为原料,经过甲苷化,酯化,氯代,亲核取代,高效氨化及水解脱保护等6个步骤,总收率44%,经一次重结晶纯化最终产品纯度达到99%以上。此路线条件温和,操作安全,终产物分离纯化简易。目前已经完成公斤级别的中试。     

Oscillatory flow in a stratified medium past an infinite porous plate with constant suction

An approximate solution to oscillatory flow past a porous horizontal plate was carried out under the following conditions

• (i) Constant suction
• (ii) Stratification of the medium due to change in density, viscosity and thermal conductivity
• (iii) Free-stream oscillation about a nonzero constant mean.

Solutions have been derived for the transient velocity, the transient temperature, the amplitude and the phase of skin friction and the amplitude and phase of the first and second harmonics of the rate of heat transfer. These are shown on the graphs. The effects of the suction parameter S, the stratification parameter λ, the frequency λ and the Eckert number E are discussed.     

肿瘤PET分子探针3-O-(2-18F-氟乙基)-L-多巴的合成及初步生物学评价

正电子类氨基酸显像剂是¹⁸F-氟代脱氧葡萄糖（¹⁸F-Fluorodeoxyglucose,¹⁸F-FDG）在临床肿瘤PET显像应用中的重要补充。针对6-¹⁸F-氟-L-多巴（¹⁸F-FDOPA）前体制备及标记过程的复杂性,本研究设计合成了一种新型¹⁸F-标记的氨基酸类肿瘤PET显像剂3-O-(2-¹⁸F-氟乙基)-L-多巴（3-O-(2-¹⁸F-fluoroethyl-L-DOPA,¹⁸F-FEDOPA）,并对其内生物分布及肿瘤PET显像进行了评价。以L-多巴（L-DOPA）为原料经多步反应合成标记前体化合物-N-叔丁氧羰基-(3-O-甲苯磺酸酯乙基-4-O-叔丁氧羰基)-L-多巴甲酯,通过¹⁸F-亲核取代反应实现放射性标记,经半制备高效液相色谱纯化、盐酸水解、NaOH中和后得到¹⁸F-FEDOPA注射液。放化合成时间为90 min,放化产率（33±6）%（n=10,衰减校正）,放射性比活度为55 GBq/μmol,放化纯度>99％,4 h后测定放化纯度>95%,稳定性良好。小鼠体内生物分布表明,¹⁸F-FEDOPA主要经肾脏代谢,心脏和脑组织摄取值较低,骨骼摄取随时间无明显变化。microPET/CT显像显示,¹⁸F-FEDOPA在H22和S180肿瘤组织有明显摄取;与¹⁸F-FDG相比,¹⁸F-FEDOPA在注射60 min时肿瘤与心（或脑）的比值高。因此,¹⁸F-FEDOPA有望成为一种新型氨基酸代谢类肿瘤PET显像剂。