超声彩色血流成像的计算机快速仿真方法

研究超声彩色血流成像的快速仿真方法,克服原先仿真方法非常耗时的缺点。方法超声彩色血流成像计算机仿真中,血流信号是对成像区间内所有点散射体的回波信号累加而得到的。通过引入新的等效散射体模型,可以大大降低散射体的密度,从而减少计算回波信号所需时间。在计算机上用Matlab编程来进行仿真实验,对以往仿真方法和基于等效散射体模型方法的性能进行比较。结果实验表明:基于等效散射体模型的仿真,在保证相同流速精度的前提下,仿真速度比传统方法提高了10倍以上。结论基于等效散射体模型的仿真方法能极大地提高超声彩色血流成像的仿真速度,可以为超声彩色血流成像的方法研究提供便利。     

一种新的B链C端去四肽胰岛素的研制方法

报道了将单体胰岛素前体(MIP)经胰蛋白酶和羧肽酶B两步连续酶切获得B链C端去四肽胰岛素(DTI)的方法。MIP由甲醇酵母表达,最高发酵表达量达到150mg/L。发酵液中MIP通过疏水层析,分子筛初步纯化后直接进行酶切,在胰蛋白酶酶切3h后加入抑制剂paminobenzamidine处理15min,然后直接加入羧肽酶B酶切6h,再通过反相柱纯化即可得到纯品DTI,从分子筛到最后DTI,总纯化得率达到77%。按中国药典小白鼠惊厥法测定得DTI的生物活力为22IU/mg,是胰岛素的80%,在Superdex G-75分子筛上测定DTI的解离聚合曲线,证明其是单体。     

Simulation of Migration of Human Epidermal Keratinocytes over Three-Dimensional Collagen Gel

We developed a novel model for studying migration of keratinocyte colonies over 3D collagen gel. It was shown that keratinocytes previously cultured on plastic and then seeded on the surface of collagen gel proliferate more actively than the primary cells. The gel density could significantly affect the morphology and migration of keratinocyte colonies. Modification of collagen gel by fibronectin-like protein or poly-L-lysine altered the morphometric parameters of colonies without significant changes in the velocity of migration.     

A Database of Accurate Electrophoretic Migration Patterns for Human Proteins

Native molecular weight (MW) is one of the defining features of proteins. Denaturing gel electrophoresis (SDS-PAGE) is a very popular technique for separating proteins and determining their MW. Coupled with antibody-based detection, SDS-PAGE is widely applied for protein identification and quantitation. Yet, electrophoresis is poorly reproducible and the MWs obtained are often inaccurate. This hampers antibody validation and negatively impacts the reliability of western blot data, resulting worldwide in a considerable waste of reagents and labour. We argue that, to alleviate these problems there is a need to establish a database of reference MWs measured by SDS-PAGE. Using mass spectrometry as an orthogonal detection method, we acquired electrophoretic migration patterns for approximately 10′000 human proteins in five commonly used cell lines. We applied a robust internal calibration of migration to determine accurate and reproducible molecular weights. This in turn allows merging replicates to increase accuracy, but also enables comparing different cell lines. Mining of the data obtained highlights structural factors that affect migration of distinct classes of proteins. When combined with peptide coverage, the data produced recapitulates known post-translational modifications and differential splicing and can be used to formulate hypotheses on new or poorly known processing events. The full information is freely accessible as a web resource through a user friendly graphical interface (https://pumba.dcsr.unil.ch/). We anticipate that this database will be useful to investigators worldwide for troubleshooting western blot experiments, but could also contribute to the characterization of human proteoforms.     

Computer Simulation of Two-Dimensional Continuum Flows by the Direct Simulation Monte Carlo Method

Abstract

Computer simulations using particles are an attractive method to extract microscopic information of flow phenomena [1]. The molecular dynamics (MD) method, in which Newton's equations of motions are integrated, gives the temporal development of the system. In the MD simulation of fluid flows, the computational region is limited to atomistic scales [2]. On the other hand, the direct simulation Monte Carlo (DSMC) method, in which collisions of particles are made on a probabilistic basis, has a potential of treating a realistic system with a macroscopic scale length retaining the atomistic details. The DSMC method provides an efficient way to integrate the Boltzmann equation from the rarefied gas to the near-continuum region. Bird clarified the validity of the DSMC method in the near-continuum flow region [3]. However, the DSMC method has not been applied to the continuum region and compared with the continuum hydrodynamics.     

重组人骨形态发生蛋白-2生物学活性测定新方法的建立

目的:采用小鼠异位成骨技术及甲基麝香草酚蓝比色法检测重组人骨形态发生蛋白-2(rhBMP-2)的生物学活性。方法:将rhBMP-2埋入小鼠肌间隙内,14d后取出新生组织,采用血清钙试剂盒检测其钙含量。结果:随着给药组剂量递增,相应地钙含量也增加,二者具有较强的量效关系。结论:此方法为本实验室独创,较传统的血清碱性磷酸酶方法更为方便、快捷,是一种能够定量检测rhBMP-2活性的新方法。     

一种检测人中期染色体原位切口移位的新方法

本研究首次详细描述了在BrdU替代4个细胞周期以上的中期染色体上进行原位染色体切口移位的方法。研究证明,切口移位效率达峰值的最适温度为15—20℃,最佳时间为10—15分钟,DNasc Ⅰ的最佳浓度为2ng/ml。用本方法进行的人外周血淋巴细胞染色体的原位切口移位带型表明,原位切口移位的染色体带型特征与已知的G带、R带有较明显的差异,是另一种新的带型。本方法较用’H-dTTP或Bio-dUTP作标记物进行染色体原位切口移位更简便、快速,不仅可用于活性基因在不同种类基因组内的分布研究,而且可能在细胞遗传学和分子生物学研究中具有更广泛的用途。     

A New Method for Mercury Removal

A method is desibed for the removal of mercury from solution by using the off-gas produced from aerobic cultures of Klebsiella pneumoniae M426. Cells growing in Hg-supplemented medium produced a black precipitate containing mercury and sulphur. The ratio of Hg:S was determined as ~1:1 by analysis using proton-induced X-ray emission, suggesting precipitation of HgS within the culture. The outlet gases produced by a mercury-unsupplemented aerated culture were bubbled into an external chamber supplemented with up to 10 mg HgCl₂/ml. A yellowish-white precipitate formed, corresponding to 99% removal of the mercury from solution within 120 min. Energy dispersive X-ray microanalysis showed that this metal precipitate consisted of mercury, carbon and sulphur. Formation of mercury carbonate was discounted since similar precipitation occurred at pH 2 and no oxygen was detected in the solid, which gave an X-ray powder pattern suggesting an amorphous material, with no evidence of HgS. Precipitation of mercury with a volatile organosulphur compound is suggested. Bio-precipitation of heavy metals by using culture off-gas is a useful approach because it can be used with concentrated or physiologically incompatible solutions. Since the metal precipitate is kept separate from the bacterial biomass, it can be managed independently.     

A New Method for Safranin Differentiation

A new method of differentiating safranin in pollen-mother-cell smears and paraffin sections is described in detail. Slides stained in safranin are dehydrated in a series of alcoholic solutions containing 1.5% picric acid with constantly decreasing percentages of water. Differentiation is principally effected in 83% alcohol containing 1.5% picric acid and completed in the final dehydration and clearing. Counterstains may be applied in clove oil if desired.     

A New Method for Synthesizing Acyclonucleosioes

Abstract

We prepared, using a phase transfer catalyst liquid-liquid or solid-liquid, a new series of acyclonucleoside analogues of allopurinol, where the ribose moiety is replaced by (hydroxy-2-ethoxy)-methyl.     

一种新的EST聚类方法

该研究发展了一种EST（expressed sequence tag）聚类方法（ESTClustering）,用于分析大规模EST测序中所产生的大量数据,以获得高质量,非重复表达序列,该方法在聚类过程中采用MEGABLAST工具对一致序列进行序列同源比较,并用phrap程序对每一EST簇进行拼接检验。这一聚类策略能降低测序错误带来的影响,有效识别基因家族成员,并避免选择性剪接的干扰,与NCB（National Center for Biotechnology Information）的UniGene clustering）方法相比,ESTClustering的聚类结果可以更好地反映表达序列的多样性,用ESTClustering对112256条拟南芥EST聚类测试,产生23581个EST簇,其中13597个EST簇有对应拟南芥基因组编码序列,与该基因组中有EST作为依据的预测基因数目接近。应用该方法对收集的147191条水稻EST序列进行聚类,形成33896个EST簇。     

A Simulation of Human Heart Function

A simulation of the function of the human heart and heart muscle has been developed in the form of a digital computer code. For a given set of values for the input variables, realistic values of the cardiac output variables are predicted. A detailed discussion of the simulation and some results obtained from its application are presented. This simulation represents a unique combination of what was known in muscle mechanics, muscle thermodynamics, and of the structure, size, and shape of the heart, into an engineering model to improve the understanding of human heart muscle function. The left ventricle (LV) is treated as a thick-walled sphere whose wall is composed entirely of muscle fibers. Force-length velocity relationships are used to determine the tension in each fiber. The pressure in the LV is computed from fiber tension and fiber structure in the LV. A lumped-parameter simulation of the arterial tree provides a load impedance for the LV. Results are presented for simulation of normal human LV performance.     

整合检验设备与计算机通讯的方法

目的 通过统一检验设备与计算机的通讯接口达到整合检验数据的目的.方法 基于Mscomm32、winsock等编程控件和数据库技术设计通用通讯工具.结果 实现了检验数据的统一通讯,统一存储.结论 通过统一接收、管理检验数据在提高检验科的管理效率的同时对医院信息系统的数据整合意义重大.     

A Functional Hypothesis for LGN-V1-TRN Connectivities Suggested by Computer Simulation

We employ computer simulation to investigate the function of neural circuitries between thalamic sensory relay nuclei, primary sensory cortices, and the thalamic reticular nucleus (TRN). Computational similarities exist between these circuits and the architecture of a simple artificial neural network. We impose processing parameters on this network architecture in keeping with anatomical and physiological details of the mammalian geniculo-cortical visual pathway, and then run the simulation on a task involving multiple simultaneous inputs from the simulated visual field. After two to three loops through the simulation, activity in cortical and thalamic units whose receptive fields include the stronger stimulus remains constant, while activity in other cortical and thalamic units activated by weaker stimuli declines toward resting values. These results suggest that the modeled neural circuitry functions to prime selective attentional mechanisms further up the visual streams toward specific portions of the total visual stimulus. Besides extending existing models and evidence about the function of these neural circuits, our results also provide physiologists with predicted activity profiles of thalamic and cortical elements of the modeled neural system for a task not yet studied experimentally.     

AMBUSH: A Computer Program for Stochastic Microsimulation of Small Human Populations

A new generation of computer simulation programs for exploring problems in demography, kinship ties, descent groups, and other kinds of connectivity in small human populations is now available for use. AMBUSH is a simulation package which may be useful for simulating effects of fertility and mortality schedules, rules of marriage and kinship, density-dependent infanticide, and other features of closed breeding groups, and their stochastic variability. The program, described here, is available from the authors . [microsimulation, demography, kinship, connectivity]     

一种新的DNA芯片的封闭方法

提出了一种新的DNA芯片的封闭方法:1-碘丙烷封闭方法,并对1-碘丙烷和琥珀酸酐两种不同的封闭方法的封闭效果进行了比较实验,研究封闭试剂、封闭时间对氨基DNA芯片杂交结果所产生的影响。结果表明:1-碘丙烷封闭效果明显好于琥珀酸杆的封闭效果,用1-碘丙烷封闭后的芯片进行杂交,芯片杂交信号强、背景噪声低,灵敏度高,整个封闭过程实验操作简单,时间短,1h即可达到所需效果。1-碘丙烷可以作为一种很好的DNA芯片封闭试剂。