Histone deacetylase inhibitors augment doxorubicin-induced DNA damage in cardiomyocytes

Histone deacetylase inhibitors have emerged as a new class of anticancer therapeutics with suberoylanilide hydroxamic acid (Vorinostat) and depsipeptide (Romidepsin) already being approved for clinical use. Numerous studies have identified that histone deacetylase inhibitors will be most effective in the clinic when used in combination with conventional cancer therapies such as ionizing radiation and chemotherapeutic agents. One promising combination, particularly for hematologic malignancies, involves the use of histone deacetylase inhibitors with the anthracycline, doxorubicin. However, we previously identified that trichostatin A can potentiate doxorubicin-induced hypertrophy, the dose-limiting side-effect of the anthracycline, in cardiac myocytes. Here we have the extended the earlier studies and evaluated the effects of combinations of the histone deacetylase inhibitors, trichostatin A, valproic acid and sodium butyrate on doxorubicin-induced DNA double-strand breaks in cardiomyocytes. Using γH2AX as a molecular marker for the DNA lesions, we identified that all of the broad-spectrum histone deacetylase inhibitors tested augment doxorubicin-induced DNA damage. Furthermore, it is evident from the fluorescence photomicrographs of stained nuclei that the histone deacetylase inhibitors also augment doxorubicin-induced hypertrophy. These observations highlight the importance of investigating potential side-effects, in relevant model systems, which may be associated with emerging combination therapies for cancer.     

刚性系统数字仿真算法

介绍刚性的本质,综述刚性算法、间断处理、实时算法、微分代数问题、稳定性、并行算法的一些结果,给出在这个领域的进一步研究的建议。     

Cu_2O的生成对CuO纳米薄膜电极锂离子电池特性的影响

以铜箔为基底,采用一步水热法制备CuO纳米结构薄膜,通过XRD、SEM、XPS对所制薄膜的形貌、成分进行分析,并测试CuO薄膜电极的锂离子电池特性,研究铜基底与CuO薄膜之间生成的Cu_2O对电池性能的影响。结果表明,较高反应温度有利于铜基底和薄膜之间Cu_2O的生成,且利于改善CuO薄膜纳米结构;140℃反应温度下生长出的CuO薄膜电极,其比电容和电容保持率均高于80℃反应温度下生长出的CuO薄膜电极,其电池循环能力更强,这与铜基底和CuO薄膜之间产生的Cu_2O层有关。     

高砷烟尘酸性氧化浸出砷和锌的试验研究

采用酸性氧化浸出工艺对某冶炼厂高砷烟尘进行湿法浸出砷、锌的试验研究。通过单因素试验确定最佳浸出工艺条件。结果表明,采用pH值为2的稀硫酸溶液,在浸出温度80℃、浸出时间105min、液固体积质量比10∶1、H2O2添加量1.75mL/g(烟灰)、搅拌速度705r/min的条件下,砷、锌浸出率分别达到78.25%和85.42%。     

吉林西部盐碱区农田土壤盐碱程度与碳的稳定同位素比值的关系

为了探讨农田土壤盐碱程度对土壤碳固定和碳排放的影响,选取吉林西部不同开发年限的盐碱旱田、水田为研究对象,进行野外采样和实验测量。测定土壤盐碱程度的基本理化指标:土壤pH、电导率和碱化度;同时测定土壤有机碳和无机碳的稳定碳同位素比值。研究结果表明,旱田土壤整体盐碱程度较高、固碳水平较低,土壤-大气碳循环较慢。随开发年限的增加,盐碱程度没有显著降低;而水田土壤盐碱程度相对较低,固碳水平较高,促进了土壤-大气碳循环。随开发年限的增加,土壤盐碱程度得以改善,土壤固碳水平提高。总体而言,玉米的种植无法较为有效地改善土壤盐碱程度和土壤碳的固定,而水稻的种植则可以改善土壤条件,有利于土壤对碳的固定从而降低碳排放。在全球温室效应大环境下,研究区应大力关注水稻种植产业的发展,改造盐碱土壤,为减缓区域变暖做出一定贡献。     

First-principles study of the interactions of hydrogen with low-indexsurfaces of PdCu ordered alloy

PdCu catalysts play a key role in several hydrogen-involved processes. Among these reactions, the interaction ofhydrogen with PdCu essentially determines the catalytic performance. However, the response of PdCu to surroundinghydrogen has been poorly investigated, especially for specific facets of PdCu at different environment.In this work, taking temperature and hydrogen pressure into account, we studied the hydrogen-surface interactionsfor four low-index surfaces of PdCu through first-principles calculations. It was found that H-PdCu adsorptionstrong relies on the facets, hydrogen coverage, and reaction environment (temperature and H-pressure).Our work highlights the importance of the environment on the nature of catalyst surfaces and reactions andoffers a plausible way to investigate the interactions between gas and the surfaces of nanocatalysts in realreactions.     

基于模拟有限差分法的离散裂缝模型两相流动模拟

模拟有限差分作为一种新型数值计算方法,因其良好的局部守恒性和对复杂网格系统的适用性,在计算流体力学和油藏数值模拟中得到应用。将模拟有限差分方法进一步应用于离散裂缝流动模拟中,对模拟有限差分法的基本原理进行详细阐述,建立相应的离散裂缝数值计算格式,并采用IMPES方法对其两相流问题进行求解,并与实验结果对比。对比结果验证了新方法和程序的正确性,通过复杂离散裂缝算例进一步验证了方法的正确性和程序的鲁棒性。     

Structures of magnetic null points in reconnection diffusion region: Cluster observations

Magnetic reconnection is a very important and fundamental plasma process in transferring energy from magnetic field into plasma. Previous theory, numerical simulations and observations mostly concentrate on 2-dimensional （2D） model; however, magnetic reconnection is a 3-dimensional （3D） nonlinear process in nature. The properties of reconnection in 3D and its associated singular structure have not been resolved completely. Here we investigate the structures and charactedstics of null points inside the reconnection diffusion region by introducing the discretized Poincar6 index through Gauss integral and using magnetic field data with high resolution from the four satellites of Cluster mission. We estimate the velocity and trajectory of null points by calculating its position in different times, and compare and discuss the observations with different reconnection models with null points based on characteristics of electric current around null points.     

均值不等式的推广及应用

本文对均值不等式在指数方面作了推广,并举例说明本文的推广拓宽了均值不等式的应用,使一些问题简化.     

中美研究型大学通识课程的比较研究——以哈佛大学、北京大学为例

哈佛大学与北京大学在通识课程的目标、设置、管理机构及配套制度等方面存在着许多不同之处。在课程目标方面,哈佛大学通识课程的目标是培养“全人”;北京大学则将扩宽知识面,为专业打基础作为其目标。在课程设置方面,哈佛大学的通识课程在本科生课程中占有较大的比例,通识课程数量多,涉及领域广;而北京大学通识课程的比例远小于专业课程,只占三分之一,其内部全校性公共课所占比例较大,通选课比例较小,通识课程数量较少。在课程的管理方面,哈佛大学有着专门的管理机构;而北京大学的通识教育则没有专门的管理机构,仍旧归属教务部门管理。鉴于此,应借鉴哈佛大学之可取之处：理清通识教育的内涵,明确通识课程的目标;加强通识课程建设;建立独立的通识课程管理机构及相应的配套制度。