超速离心机操作应用及基本理论

高速离心机、超速离心机在医学生物领域里的实验室、医院、大中院校、科研单位等用于分离细胞和细菌;纯化和分离病毒、RNA、DNA、质粒和蛋白质等生物大分子.     

质谱技术在中药小分子与生物大分子相互作用研究中的应用

中药发挥药理作用具有多组分,多靶点的重要特点。研究中药化学成分与生物大分子之间的相互作用不仅能够为阐明中药发挥药理作用的机理和物质基础提供科学依据,而且能够为新药设计提供理论指导。软电离质谱技术,尤其是电喷雾质谱(ESI-MS)和基质辅助激光解吸电离质谱(MALDI-MS)在一定条件下能够使药物与生物大分子形成的复合物完整地转移到气相中并被检测到,在中药小分子与生物大分子相互作用的研究中具有很大的优势。同时,色谱-质谱联用技术在中药复杂体系与生物大分子相互作用的研究中也显示出很大的应用潜力。本文介绍了质谱技术在药物与生物大分子相互作用研究中的应用原理,并总结了近年来软电离质谱技术在中药小分子与生物大分子相互作用研究中的应用。     

基于D-S证据理论的超速离心机健康状态评估方法

超速离心机的运行健康状态评估是确保离心机安全、稳定运行的基础.介绍了超速离心机的主要状态参数及检测技术,分析了常用的健康状态评估方法.利用人工神经网络实现不同信源的超速离心机状态信息评估,再根据D-S证据理论对各子神经网络的输出结果进行融合,建立了超速离心机运行健康状态综合评估方法.实例验证了该方法的有效性和准确性.     

卧式螺旋沉降离心机故障分析及对策

卧式螺旋沉降离心机在固-液分离中应用,主要是澄清液相,将固相有效脱水。对此,需保证固相得以有效输送,才能保证这两项任务顺利完成。在相关技术更新换代下,卧式螺旋沉降离心机性能、质量也在不断提升,以往高速离心机、超速离心机获得进一步发展,超速冷冻离心机和超大容量冷冻离心机被应用于生产中。实际使用中,由于设备长期处于连续运转状态等原因,容易出现振动过大、泄漏以及螺旋输送器叶片严重磨损等问题,严重影响生产工作的进行,无法保证分离效果。因此,需对卧式螺旋沉降离心机故障有全面、深刻认知,本文分析了离心机常见的几种故障以及故障产生原因,探讨合理的应对策略,以保证离心机的使用成效。     

分析超速离心机的光学检测器

分析超迷离心技术（简称AUC）是表征大分子溶液特性的一种行之有效方法,通过选择适当的转子速度进行沉降平衡或沉降速度试验,利用样品光吸收、折射、干涉、或荧光特性建立的光谱方法检测离心池中样品的沉降行为。然而,三种通用检测器（吸收、干涉、和荧光检测器）受到被测溶液浓度和大分子复杂性方面的限制,检测精度低、速度慢、不能做到真正在线获取数据进行分析。因此,改进原有检测器、研发新型检测器是AUC工作未来重要任务。目前除商售检测器外,还有多波长荧光检测器、多波长吸收检测器、小角激光散射检测器、高精度干涉仪、浊度检测器、拉曼检测器等也被部分研究者用在分析超速离心机里。     

湖南吉尔森新产品超速离心机亮相CISILE 2014

正2014年5月21日,湖南吉尔森科技发展有限公司在第12届中国国际科学仪器及实验室装备展览会举办的新产品发布会引起业内关注——国产超速离心机终于问世了。离心机广泛应用干生物细胞分离、制药、医学、石油化工、农业、食品卫生、核原料提纯等领域。通常把转速大于3万转/分以上的称为超速离心机。转速越快,离心力越大,样品分离的效果越好。目前,国际上先进的超速离心机转速可达15万转/分。     

基于人工神经网络的医用离心机故障监测机理研究

通过对医用离心机常见故障分析研究,对设备振动信号的采集、处理和提取特征参数的方法,利用人工神经网络原理,对医用离心机系统工作状态故障进行智能监测,并通过实验对DLB-7型离心机工作机理进行实验,获得了一些富有实际意义数据,从而为该技术的实际应用奠定了理论与实验基础。     

生物质谱技术及其在RNA检测中的应用

生命科学的需求促进质谱技术的发展,现代的质谱技术为生命科学研究提供丰富的检测手段,本文重点介绍生物质谱技术的特点、性能以及质谱技术的进展;及质谱技术在RNA研究领域的方法学,包括核酸的纯化方法、核酸的离子化技术、核酸的分子量检测技术和核酸质谱数据的解析方法及其软件;以及质谱在核酸领域的具体应用,包括质谱在测序、定量、转录后修饰、核酸的指纹识别、蛋白和核酸相互作用等方面的应用。     

分析超速离心机的多波长检测系统及其应用

分析超迷离心技术应用离心力场在对样品分级分离的同时借助光学系统检测离心池内大分子分布及相互作用。本文阐述用于分析超迷离心机的新型多波长检测器（MWL-AUC）,它以现代CCD uv-vis分光仪为基础,几乎可用所有波长的光线同时检测同一半径处沉降样品的分布,通过沉降平衡和沉降速度试验能够获得更多信息源并应用于生物科学和工业多聚物的研究。     

气动超速离心机

本文简要介绍了气动超速离心机的设计原理。用气体动力学分析了仪器关键部件——定子的喷嘴大小和入射气流,得出转子运动方程式,算出转速与驱动压力的关系曲线,与实验符合较好。对转子材料所受应力也作了分析,指出用非金属材料代替金属材料,具有比重小、安全可靠、材料易得等优点。该仪器无需加真空设备,样品容量为1.44m1,转速高达10.5万转/分,最大离心力为210000g。     

Studies on the shear stability of macromolecular additives by size exclusion chromatography

Factors affecting the mechanical stability of polyalkylmethacrylate type additives are comparatively examined for different shear degradation test methods and routine engine service, taking into account rheological and size exclusion chromatography data. The shear test methods are assessed regarding the MWD of the degraded additives. The extent of degradation of macromolecular additives and the molecular weight distribution (MWD) of the degraded products depend on the nature and extent of shear stress, average molecular weight, MWD, chemical structure, nature of the base oil and temperature. The shape of the MWD of the sonicated and automotive service subject additives was found to be similar, unlike that of the additives sheared by the diesel injector method. These are narrower and more dependent on the initial MWD of the additive, especially in the case of the additives with broader MWD. A shear test that better correlates with service has to take into account not only the control of shear stress, by appropriate calibration, but also a suitable degradation mechanism.     

Comparison of single‐particle analysis and electron tomography approaches: an overview

Three‐dimensional structure of a wide range of biological specimens can be computed from images collected by transmission electron microscopy. This information integrated with structural data obtained with other techniques (e.g., X‐ray crystallography) helps structural biologists to understand the function of macromolecular complexes and organelles within cells. In this paper, we compare two three‐dimensional transmission electron microscopy techniques that are becoming more and more related (at the image acquisition level as well as the image processing one): electron tomography and single‐particle analysis. The first one is currently used to elucidate the three‐dimensional structure of cellular components or smaller entire cells, whereas the second one has been traditionally applied to structural studies of macromolecules and macromolecular complexes. Also, we discuss possibilities for their integration with other structural biology techniques for an integrative study of living matter from proteins to whole cells.     

Quantitative fluorescent speckle microscopy: where it came from and where it is going

Fluorescent speckle microscopy (FSM) is a technology for analysing the dynamics of macromolecular assemblies. Originally, the effect of random speckle formation was discovered with microtubules. Since then, the method has been expanded to other proteins of the cytoskeleton such as f‐actin and microtubule binding proteins. Newly developed, specialized software for analysing speckle movement and photometric fluctuation in the context of polymer transport and turnover has turned FSM into a powerful method for the study of cytoskeletal dynamics in cell migration, division, morphogenesis and neuronal path finding. In all these settings, FSM serves as the quantitative readout to link molecular and genetic interventions to complete maps of the cytoskeleton dynamics and thus can be used for the systematic deciphering of molecular regulation of the cytoskeleton. Fully automated FSM assays can also be applied to live‐cell screens for toxins, chemicals, drugs and genes that affect cytoskeletal dynamics. We envision that FSM has the potential to become a core tool in automated, cell‐based molecular diagnostics in cases where variations in cytoskeletal dynamics are a sensitive signal for the state of a disease, or the activity of a molecular perturbant. In this paper, we review the origins of FSM, discuss these most recent technical developments and give a glimpse to future directions and potentials of FSM. It is written as a complement to the recent review (Waterman‐Storer & Danuser, 2002, Curr. Biol., 12, R633–R640), in which we emphasized the use of FSM in cell biological applications. Here, we focus on the technical aspects of making FSM a quantitative method.     

电感法测量磁流变液沉降系数的研究

磁流变液的沉降稳定性是磁流变液研究和生产所要考虑的重要因素之一，测量磁流变液的沉降特性的电感法利用了磁流变液的磁学特性，具有原理清晰、测量方便的优点。现有的基于离心装置的测量沉降性能的电感方法的实验结果与理论推导的偏差这一个数量级以上，对该方法的误差分析发现：由于电感工作区域选择不合理，沉降系数的最大值和最小值相差一倍；由于电感结构不合理，电感值对沉降位移的灵敏度低，测量误差增加；采用了离心力加快沉降速度，粒子的沉降速度大，均匀低速的假设条件不再满足，理论计算模型和实际情况偏差大。在此基础上，设计了一种结构合理的测量电感和相应的测量装置及测量方法，该方法克服了原有方法中存在的缺陷与不足，并且无需离心装置加快沉降速度。新方法测量数据与理论推导相吻合，能够在10h以内‘表确地测得某商品化磁流变液的沉降系数，长时间的测量显示该方法具有较高的测量稳定度。     

有机化合物分子式的组合方式和分布规律的研究及其应用

多年的观察和研究初步证实，自然界有机人合物可能存在的合理分子式在种类和数量上是有限和可知的，对分子量１０００以下的式范围了符合实际的界定方法和计算式。据此已经人工书写或计算机打印出分子量１６－８００、只Ｃ、Ｈ、Ｏ、Ｎ分子式２０３４７０个，初步估算分子量到１０００时共有分子式４７４０００个。若以分子量为横坐标，分子式中的碳原子数为纵坐标作图，除个别外，这些分子式均分布在坐系的一个三角形区域内，因而称     

Biomolecule mass spectrometry by fast heavy ion induced desorption

Fast heavy ions like fission fragments from a ²⁵²Cf-source induce desorption of molecular and fragment ions when they hit the surface of a bioorganic solid. This effect can be exploited in the ion-source of a mass spectrometer. As compared to other ionization methods available in mass spectroscopu this method is particularly powerful for large thermally labile biomolecules, e.g. proteins. Recently quasi-molecular ions from a protein of molecular weight 13 980 amu were observed in our laboratory with the use of fast ion induced desorption and the time-of-flight technique. A new area of research is rapidly developing. It involves studied of mechanisms for fast ion induced desorption and biomolecule ion formation and the development of experimental tools to determine the mass of these large molecular ions. Both ²⁵²Cf fission fragments and beams from several heavy ion accelerators are used in this research. The field will be briefly reviewed and results obtained recently at Uppsala will be discussed in some detail.     

Insights into virus capsid assembly from non-covalent mass spectrometry

The assembly of viral proteins into a range of macromolecular complexes of strictly defined architecture is one of Nature's wonders. Unraveling the details of these complex structures and the associated self-assembly pathways that lead to their efficient and precise construction will play an important role in the development of anti-viral therapeutics. It will also be important in bio-nanotechnology where there is a plethora of applications for such well-defined macromolecular complexes, including cell-specific drug delivery and as substrates for the formation of novel materials with unique electrical and magnetic properties. Mass spectrometry has the ability not only to measure masses accurately but also to provide vital details regarding the composition and stoichiometry of intact, non-covalently bound macromolecular complexes under near-physiological conditions. It is thus ideal for exploring the assembly and function of viruses. Over the past decade or so, significant advances have been made in this field, and these advances are summarized in this review, which covers the literature up to the end of 2007.     

The structure difference of proteins isolated on substrate with different techniques as studied by the atomic force microscope

The height and width of proteins deposited on mica substrates were measured from cross sections of their atomic force microscope (AFM) images. The tapping mode AFM gave very stable and reproducible images for high molecular weight proteins. The following results were obtained: (1) The thickness of mono-, bi-, and trilayered purple membranes was 5.3, 10.4, and 16.0 nm, respectively. The calibration curve of z range of AFM based on the above data was linear. The deviation of the calibration curve at the origin was < 0.6 nm. (2) The height of slow form α-2-macroglobulin (α2M) molecule changed depending on sampling methods. When the protein was freeze-dried on a mica substrate prewetted with water, α2M gave the highest value for its height. The fact that freeze-drying, especially after prewetting of the substrate, was effective to prevent flattening of the molecule suggested that sample deposition must be as gentle as possible to keep the original height of the molecules. (3) Furthermore, we compared differences of height and width between α2M and myosin filament. The result suggested that α2M had a disk-like rather than a spherical form. Large proteins such as α2M are still difficult to crystallize for x-ray analysis, and we tested the AFM method for the study of minute height differences of such proteins.     

An EKF based estimation scheme for sedimentation processes in vessels using EIT-type measurement data

Sedimentation is usually parameterized by settling curves, settling velocities and the concentration of the constituent layers. The estimation of sedimentation parameters leads to useful information in the fields of environmental and industrial engineering. This paper presents an extended Kalman filter (EKF) based dynamic estimation scheme to extract sedimentation parameters from electrical impedance tomography (EIT) measurements obtained across the electrodes attached to the walls of a process vessel. A state evolution model has been developed for three-layer sedimentation based on the solids flux theory for batch sedimentation. The performance of the proposed method has been verified by carrying out numerical experiments.