可生物降解纳米粒子制备研究进展

可生物降解纳米粒子作为纳米级药物载体，在蛋白质、多肽、疫苗、基因等药物控制释放方面具有广阔的应用前景。它的优点不仅在于其能有效地降低药物毒性，屏蔽药物不良气味并对药物控制释放，纳米粒子超微小的粒径能够有效地穿越组织间隙被细胞吸收，可通过人体的毛细血管甚至血脑屏障(BBB)来发挥药效。本文重点介绍近年来国内外可生物降解纳米粒子制备方法的进展情况，同时概述了各种影响因素和条件，并对可生物降解纳米粒子的发展做出展望。     

氧化铁纳米粒子用于癌症的诊断和治疗

癌症是目前世界上最危险的疾病之一,目前已有的治疗方案包括外科手术,化疗,放疗等。但这些方案的治疗结果并不理想同时也会有一些严重的副作用,从而推动了新的治疗工具的开发。氧化铁纳米粒子因其细胞毒性低,尺寸小和独特的磁性等特点,为癌症的诊断和治疗提供了新的思路。本文着重于介绍氧化铁纳米粒子的制备以及在癌症诊断和治疗中的应用。     

纳米羟基磷灰石在药物载体中的应用

综述了纳米羟基磷灰石（HAP）作为药物或基因载体的研究现状与其生物相容性评价，指出了HAP纳米粒子作为药物或基因载体的主要发展趋势及存在的问题。药物或基因载体的研究较多，但是尚未找到一种理想的载体材料。作为一种新的药物基因载体，HAP纳米粒子有高的药物吸附量及良好的生物相容性，有望作为一种新的基因药物载体。     

刺激响应抗肿瘤药物载体研究进展

药物载体对于癌症的有效治疗非常重要,主要介绍光、酶、pH等刺激响应型纳米粒子及凝胶类药物载体性能及其在药物载体中的应用。     

微流控制备新型功能纳米粒子研究进展

纳米粒子在显示器、催化剂和生物医学等领域有着广泛的应用,其可控制备一直是研究的重点。与传统的间歇釜式生产工艺相比,微流控技术具有高效混合、传质传热快、反应条件精准可控以及可在线分析等特点,可用于高效连续化合成单分散纳米粒子,并为新型功能纳米粒子的开发提供了平台。本文主要介绍了近年来微流控技术在新型功能纳米粒子制备中的应用,重点综述了在量子点、金属及金属氧化物纳米粒子制备中的研究进展,并对其未来方向进行展望。     

纳米药物载体研究概述

纳米粒子药物载体可以有效提高难溶性药物的生物利用度,因为纳米粒子的粒径远小于毛细血管通路,一般在10～1 000 nm之间;利用纳米材料,将半衰期短的药物制备成缓释药,可以避免多次重复给药;将易水解的口服药物通过药物载体输送可以避免药物直接接触人体内的各种水解酶;可通过修饰纳米载体来达到靶向给药的目的,降低药物对正常组织的毒副作用;纳米载体具有生物易降解的特性且能携带不止一种药物。     

用于药物载体的纳米粒子的研究进展

抗肿瘤药物的纳米载体具有广阔的应用前景.按照应用于抗肿瘤药物给药系统的不同类型的纳米材料及制备方法,综述了纳米脂质体、固体脂质纳米粒、纳米胶束及纳米粒等主要纳米药物载体近年来在药物输送系统上的应用及研究进展,并展望了其发展前景.     

壳聚糖纳米粒子的制备方法及其作为药物递送载体的应用

以片剂、胶囊、溶液等为代表的传统药物剂型,具有生物利用率低、控制释放能力弱、依从性低等缺点。因此,寻找新型的递送载体来改善药物的有效性、稳定性及安全性尤为重要。壳聚糖纳米粒子具有生物相容性、生物可降解性、无毒,可以延长药物在吸收时的保留时间,提高药物稳定性及利用率。综述了壳聚糖纳米粒子的制备方法,如沉淀法、复凝聚法、离子交联法、微乳液法、静电自组装法等,并且总结了这几种方法及其各自优缺点。此外,还综述了壳聚糖纳米粒子在口服给药、皮肤给药、吸入给药、注射给药中的应用。最后对壳聚糖纳米粒子应用于药物递送系统进行了展望,为壳聚糖纳米粒子在药物递送系统中的未来研究和应用提供参考。     

作为药物载体的聚氨酯纳米胶束的研究进展

聚氨酯材料具有生物相容性好、合成简单且分子结构可设计性强等优点,不可降解的聚氨酯材料在生物医学领域已经得到应用。目前可生物降解聚氨酯纳米胶束用作药物载体的研究受到广泛关注。本综述主要从生物相容性、刺激响应性、靶向作用、细胞摄取能力强的聚氨酯纳米胶束这几个方面,介绍了作为药物载体的可生物降解聚氨酯纳米胶束的研究进展。     

生物素-亲和素-DNA纳米颗粒信号放大检测载体的构建

目的构建用于检测细菌、病毒等病原体DNA的生物素-亲和素纳米颗粒信号放大载体。方法设计并合成两端和一端标记生物素的寡核苷酸探针(2B/1B-DNA),与抗生蛋白链菌素葡聚糖(Poly-STV)通过生物素与亲和素作用,偶联形成大分子纳米网状颗粒,并筛选最佳探针类型及其长度、2B-DNA和Poly-STV的浓度及比例和反应条件。结果2B-DNA和Poly-STV形成纳米颗粒信号放大载体的最佳浓度分别为1μmol/L和5μmol/L,最佳浓度比为1∶5,2B-DNA长度为60bp,缓冲液为Buffer B,反应条件为55℃,800r/min,20min。结论已成功构建了生物素-亲和素大分子纳米颗粒,可作为DNA检测信号放大技术的备选载体。     

酶固定化无机载体材料的研究进展

近年来,酶固定化技术已在食品工业、医药、精细化学品工业,尤其是手性化合物等行业得到广泛应用,在废水处理方面也取得了一定进展。然而,载体材料的物理和化学性能直接影响固定化酶的催化活性。本文介绍了酶固定化常用无机载体材料一传统的无机载体材料、改性无机载体材料以及复合载体材料,并对酶固定化用无机载体材料的发展进行了展望。     

Magnetic Resonance Imaging of fluidized beds

This paper reviews recent developments in Magnetic Resonance Imaging (MRI) which enable it to follow particle motion in fluidized beds. Imaging with a spatial resolution of 400 μm and a temporal resolution of 1 ms is now feasible; particle velocities of order 1 m/s can be measured with good accuracy. The technique provides voidage fractions on a motion-picture basis and particle velocity fields. Limitations are: (i) the particles must contain appropriate atoms e.g. C or H; and (ii) currently the fluidized bed diameter cannot exceed 50 mm, though measurements from larger units will doubtless become available. MR studies on fluidized beds are described: results are reported for (i) air jets entering the bed (ii) bubbling and slugging beds and (iii) dispersion in a bubbling bed. The data are consistent with published measurements. Study (i) helps to resolve the longstanding puzzle about the behaviour of an air jet entering a fluidized or partly-fluidized bed, answering the question: does the entering air form bubbles or a continuous jet?     

MRCP在梗阻性黄疸性病变中的临床应用价值

目的探讨磁共振胰胆管成像(MRCP)对梗阻性黄疸性病变的临床应用价值,总结梗阻性黄疸的MRCP表现,提高其诊断的准确性。方法对98例经手术和病理证实的梗阻性黄疸患者的MRCP表现进行回顾性分析。结果良性梗阻性黄疸82例,其中胆系结石67例,胆管炎性狭窄13例,胆总管囊肿2例。恶性梗阻性黄疸16例,其中胆管癌7例,壶腹癌3例,胰头癌6例。结论 MRCP对梗阻的定位诊断准确可靠,是诊断良、恶性梗阻性黄疸的有效方法。     

Zinc as an Imaging Biomarker of Prostate Cancer

Zinc has long been the focus of many biological investigations because of its essential role in biology including a catalytic role in many enzymes, a structural role in the many zinc finger proteins, and a physiological role in many secretory cell processes. Divalent zinc is known to be highly abundant in healthy prostate tissues and lower in prostate cancer (PCa). Given the need for newer diagnostic methods for detection of prostate cancer, zinc-responsive probes of various types have been considered as imaging tools for detecting tissue levels of zinc. Among them, recent zinc-responsive MRI probes show great promise for non-invasive detection of zinc ion secretion from the prostate and other tissues in vivo. In this review, we summarize the need for new diagnostic tools and demonstrate how responsive zinc probes and MRI could satisfy this unmet need.     

Velocity Profiles of Suspension Flows through an Abrupt Contraction Measured by Magnetic Resonance Imaging

Velocity profiles in steady flows of fluid/particle mixtures through a duct with an abrupt contraction were measured by magnetic resonance imaging. Aqueous solutions of carboxymethyl cellulose containing particles, including spheres, disk‐like particles, and short fibers, at high volume fractions were used. As a result, a plug‐like velocity profile was observed in a straight duct flow for every suspension, but the velocity profile depends on the particle shape at contraction. Disk‐like particles caused an unsteady flow, and short fibers caused a concave shape in the velocity profile near the centerline upstream of the contraction. Spheres did not affect the flow field. The concave profile became obvious with increased volume fraction of fiber. This result is caused by the larger elongational viscosity of the fiber suspension near the centerline of the channel, as compared with that of the sphere suspension.     

新型载体树脂在色母粒中的应用研究

对不同熔体质量流动速率（MFR）的同种聚乙烯树脂在色母粒应用方面进行了比较。结果表明：载体树脂MFR的差别对色母粒的质量、加工性能和应用影响较大;高MFR树脂制备的色母粒,加工性能较好,颜料在色母粒中的分散程度较高,但对其他树脂进行着色的效果不理想。因此,应该从色母粒中颜料的分散和色母粒与着色树脂的相容性两个方面进行新型色母粒用载体树脂的开发。     

Granular temperature: Comparison of Magnetic Resonance measurements with Discrete Element Model simulations

The Discrete Element Model (DEM) is a very promising modelling strategy for two-phase granular systems. However, owing to a lack of experimental measurements, validation of numerical simulations of two-phase granular systems is still an important issue. In this study, a small two-dimensional gas-fluidized bed was simulated using a Discrete Element Model. The dimensions of the simulated bed were 44 × 10 × 120 mm and the fluidized particles had a diameter d_p = 1.2 mm and density ρ_p = 1000 kg m^− 3. The influence of different drag-force correlations was investigated. Preliminary numerical experiments were also performed to study the effects of (i) the coefficient of restitution and (ii) the modelled transverse thickness of the two-dimensional bed. Experimental measurements were made using Magnetic Resonance (MR), with the comparisons between DEM simulations and experimental measurements performed on the basis of the time-averaged velocity and granular temperature profiles of the particles. It was found that the DEM simulations of the time-averaged vertical velocity of the particles agreed well with the MR measurements. The drag-force correlation proposed by [R. Beetstra, M.A. van der Hoef and J.A.M. Kuipers, Drag force of intermediate Reynolds number flow past mono- and bidispersed arrays of spheres. AIChE Journal, 53, 489-501 (2007).] showed the best agreement with the experimental data. Fair agreement was found if the granular temperature calculated by the DEM simulations was compared with MR measurements. At lower fluidization velocities and closer to the distributor the DEM simulations under-predicted both the velocity and the granular temperature measurements using MR.     

Rheological behavior of cement pastes from MRI velocimetry

From MRI measurements, it is shown that in a flowing cement paste the thixotropic effects dominate over short time scales, while aging effects become significant over larger timescales. The steady state behavior, defined as flow properties in the intermediate period, exhibits a yielding behavior which differs from the prediction of usual yield stress models. The transition from the “solid” to the “liquid” regime is abrupt: the shear rate changes suddenly from zero to a finite value (critical shear rate) when the shear stress overcomes a critical value. These critical shear rates and shear stresses are independent of the flow conditions so that they may be considered as intrinsic material parameters. It was also shown that these results are consistent with usual macroscopic observations from conventional rheometry.     

氧化铝载体的回收

以废氧化铝载体为原料，在一定温度下与盐酸反应生成了三氯化铝，再经酸化、中和、干燥等处理，最后得到可以利用的氧化铝载体。盐酸的最适宜浓度是７ｍｏｌ／Ｌ，氧化铝载体的回收获得了较好的经济效益。