Knockdown of <Emphasis Type="Italic">MRP4</Emphasis> by lentivirus-mediated siRNA improves sensitivity to adriamycin in adriamycin-resistant acute myeloid leukemia cells

Chemotherapy remains the standard treatment for acute myeloid leukemia;however,the emergence of drug resistance is a major hurdle in the successful treatment of leukemia.The expression of multidrug resistance-associated protein 4(MRP4)induces re- sistance in the adriamycin-resistant acute myeloid leukemia cell line,K562/ADR.The aim of this study was to investigate whether knockdown of MRP4 by lentivirus-mediated siRNA could improve the sensitivity of K562/ADR cells to adriamycin.Five lenti- virus-mediated short hairpin RNAs(lv-shRNAs-MRP4)were designed to trigger the gene silencing RNA interference(RNAi) pathway.The efficiency of lentivirus-mediated siRNA infection into K562/ADR cells was determined using fluorescence mi- croscopy to observe lentivirus-mediated GFP expression.MRP4 expression in infected K562/ADR cells was evaluated by real- time PCR and Western blot analysis.The MTS assay was used to measure cell viability and flow cytometry was used to measure apoptosis.The transfection efficiency of K562/ADR cells was over 80 percent.The gene silencing efficacy of lv-shRNA1-MRP4 was superior to the other constructs.Infection of K562/ADR cells with lv-shRNA1-MRP4 led to strong inhibition of MRP4 mRNA and protein expression.Combined treatment with lv-shRNA1-MRP4 and adriamycin decreased cell growth and increased apoptosis compared to treatment with lv-shRNA1-MRP4 or adriamycin alone.These data indicate that in K562/ADR cells MRP4 is involved in drug resistance mechanisms and that lentivirus-mediated knockdown of MRP4 may enhance sensitivity to adriamycin.     

Synthesis of PbS–K2La2Ti3O10 composite and its photocatalytic activity for hydrogen production

Photocatalyst, lead sulfide (PbS )-intercalated layer perovskite-type compound (K2La2Ti3O10), was synthesized via ion-exchange reaction, butylamine pillaring and sulfuration processes under the assistance of the microwave irradiation. The structure of the photoc atalysts was determined by means of powder X-ray diffraction, scanning electron microscope, ultraviolet- visible diffuse reflection spectra and photoluminescence measu rement. And the photocatalytic activity of the composite compound for hydrogen production was also investigated. The experimental results showed that the intercalation of PbS in the layered space of K2La2Ti3O10 greatly improved the absorption edge and the photocatalytic activity. Hydrogen production of the PbS–K2La2Ti3O10 was 127.19 mmol/(g cat) after 3 h irradiation of ultraviolet light.     

羟基喜树碱联合丝裂霉素诱导人白血病K562细胞凋亡

观察羟基喜树碱与丝裂霉索联合应用对人白血病细胞K562的作用效果,并探讨其机制。不同浓度羟基喜树碱与丝裂霉素单独及联合作用于人白血病细胞K562后,应用台盼蓝拒染法检测细胞生长抑制率,计算合用指数（CI）,流式细胞仪（FCM）检测K562细胞凋亡率,吖啶橙（AO）荧光染色和透射电镜观察凋亡形态学变化。结果表明：单独应用时羟基喜树碱和丝裂霉素的IC50分别是8μ/mL和12．5μg/mL,联合应用时IC50下降为4μg/mL（HCPT）和3．6μg/mL（MMC）,CI=0．78,为协同效应。羟基喜树碱与丝裂霉素单独及联合应用均可诱导K562细胞凋亡。2种药物联合应用时的凋亡率高于各自单独用药。羟基喜树碱与丝裂霉素联合应用可以通过共同诱导细胞凋亡。协同抑制人白血病细胞生长。     

采用正交设计和响应曲面设计法优化芦苇随机扩增多态DNA体系

采用正交设计和响应曲面设计(RSD)优化适合于芦苇[Phragmites australis (Cav.)Trin.ex steud]增多态DNA(RAPD)的反应体系,结果确定芦苇RAPD反应体系的最佳方案为：在PCR扩增程序,冷启动,94℃变性1min,36℃复性90s,72℃延伸2min,40个循环;72℃延伸7min,4℃保存;25μl反应体系包括模板DNA 60ng、三磷酸脱氧核苷酸(dNTP)7．5mmol、Taq酶1．5u、引物5pmol。     

嗅觉系统神经网络模型字符识别中的应用

Freeman在大量神经生理实验的基础上建立了生物嗅觉系统的非线性神经网络模型,即K系列模型．其中,KⅢ模型是一种混沌神经网络,它的模式识别机制与以往的人工神经网络完全不同,更接近实际生物神经系统的工作模式．研究通过对26个英文字符的学习、识别研究得出,系统相对于传统的神经网络有着很强的学习能力,学习5～6次就能有很好的识别能力,在10次达到最优学习效果,并与真实神经系统学习过程中的倒“U”曲线相对应．     

软硬互层岩滑坡的变形特征及稳定性分析 ——以湖南郴州S215公路K3+172~K3+252段滑坡为例

在软硬互层岩石中,地质灾害极易发生。本文以S215公路K3+172~K3+252段滑坡为研究对象,分析了该滑坡的空间形态、物质组成和变形特征,采用极限平衡法,选择折线型滑动模型,在两种不同工况下对其稳定性进行了计算,最后对滑坡稳定性进行了评价。滑坡在天然工况I条件下为基本稳定状态,在暴雨工况Ⅱ条件下为不稳定状态。提出了多级抗滑桩工程、截排水工程、坡腰平台复绿工程、道路路面修复工程和监测工程相结合的综合防治工程,为该滑坡的后期治理提供了依据。     

2种山姜属植物挥发性成分的GC-MS分析

采用同时蒸馏萃取法提取桂南山姜茎叶和毛红豆蔻茎叶的挥发油,以不同的毛细管柱进行分析,找出最佳的分析条件,用归一化法测定各个成分的相对含量,并利用气相色谱-质谱联用技术(GC-MS)对其化学成分进行分析鉴定.从桂南山姜茎叶的挥发油中分离鉴定出了65个化合物,占其挥发油总成分的95.40%;从毛红豆蔻茎叶的挥发油中分别分离鉴定出了71个化合物,占其挥发油总成分的92.38%.     

混凝土塑性损伤模型参数的研究

基于相关的试验研究成果,提出了一种确定混凝土塑性损伤模型(KC模型)强度参数取值的方法.针对KC模型损伤参数取值依赖于单元尺寸的问题,以我国混凝土规范为基准,阐述了损伤参数值的调整方法,使得数值计算结果更加合理.利用ANSYS/LSDYNA模拟混凝土常规三轴压缩试验,KC模型分别采用本文确定和程序自动生成的强度参数值,并将计算结果与国内外试验结果比较,研究表明:采用本文提出的方法确定KC模型强度参数值比较合理.     

基于光诱导荧光的维生素K1检测方法研究

建立一种灵敏度高、选择性好的基于紫外光诱导荧光的维生素K1(VK1)检测方法.不发荧光的VK1经紫外光(254nm,15W)照射后可转变为具有很高荧光量子产率的光化产物,检测出其特征荧光峰在465nm处;当加入咪唑并经光诱导后,光化产物荧光特性发生变化,在330nm处又出现一新的较强荧光发射峰,两峰间的stokes位移长达135nm.同时发现,随着VK1浓度的增加,465nm处的荧光峰强度增加,而330nm处的峰强度反而减小.方法的检出限为0.003#g·mL-1(S/N=3),对1.0#g·mL-1 VK1溶液进行11次平行测定,相对标准偏差(RSD)为2.4%.该法用于注射液及人血清中VK1含量测定,回收率为97%~104%,结果令人满意.     

Millennial climate changes since MIS 3 revealed by element records in deep-sea sediments from northern South China Sea

High resolution elemental MD05-2903 from the northern South records in core China Sea were obtained from XRF scanning and grain size and mineral component analyses. The K/Ti curve reveals climate changes since MIS 3 on a millennial scale, representing one of the best such records so far from deep-sea sediments of the South China Sea. When compared our K/Ti record with other climate records from high latitude ice cores and from East Asia stalagmites, variations in the K/Ti record show some typical saw-shaped features of rapid climate changes in the Northern Hemisphere. Grain size analysis reveals a close relationship between variations in K/Ti and in the fine end-member grain size. XRD analysis confirms that high K/Ti layers were dominated by K-rich weathering minerals, especially illite, while low K/Ti layers contain low illite but high abundance of Ti-rich heavy minerals. Therefore, the K/Ti record reflects changes in the input and deposition of fine weathering minerals and heavy minerals in the northern South China Sea region during stadials and interstadials. These elemental changes were largely con- trolled by variations in rainfall, erosion, and fluvial trans- portation induced by East Asia Monsoon.