黄河兰州段水体中有机污染物对MCF-7细胞凋亡的影响及其机制

采用固相萃取法提取黄河兰州段中山桥(污染断面)、什川桥(自净断面)和新城桥(清洁断面)三个断面水样中有机污染物,用流式细胞仪和激光共聚焦显微镜检测不同断面有机污染物对MCF-7细胞染毒后的周期分布、细胞凋亡率和细胞内游离[Ca2+]i的浓度,探讨水体中有机污染物的细胞毒性作用机制及其与细胞凋亡的关系.结果表明:染毒48 h,各断面MCF-7细胞的凋亡率由高到低依次为中山桥组(31.40±3.00)％、新城桥组(17.63±0.47)％、什川桥组(13.37±1.43)％,均显著高于对照组(8.1±0.25)％(P＜0.01);各组细胞主峰均在G0/G1期积聚(≥55％),说明有机污染物主要作用于细胞的G0/G1期,使细胞停滞于此期.各断面各剂量组有机污染物分别作用于MCF-7细胞24,48,72 h后,在不同时点细胞内[Ca2+]i浓度均升高,均显著高于对照组(P＜0.01);各组细胞内[Ca2+]i浓度随染毒时间的延长呈下降趋势,具有时间效应关系;在不同时点上无钙离子组和含钙离子组间均有显著性差异(P＜0.05),提示钙离子浓度增加与外钙无关.研究表明,黄河兰州段水体中有机污染物可影响体外MCF-7细胞的周期分布并诱导细胞凋亡,其作用机制还需进一步探讨.     

培养基再利用对螺旋藻增殖和低温耐受性的影响

在适宜温度(28±2)℃和低温(16±2)℃条件下,比较研究重复利用Zarrouk培养基(RZ)和新配制培养基(NZ)对钝顶螺旋藻(Spirulina platensis,SP)增殖和色素成分的影响,探讨培养基再利用对SP生长和低温耐受性的调节作用.结果发现,与采用NZ培养基相比,尽管在适宜温度下完全RZ培养基导致藻细胞增殖速率和生物量降低,但添加50%的RZ培养基(1/2RZ)不仅对藻细胞的增殖速率和生物量无明显影响,而且藻细胞中的主要色素含量明显升高.进一步发现,RZ可增强低温培养藻细胞对可见光的吸收,促进细胞叶绿素的含量.结果提示,培养基的合理再利用可获得SP最大生物量,增加SP中色素蛋白和胡萝卜素的累积,增强SP对低温的耐受性,因此对提高低温培养SP产量和品质具有一定的实践意义.     

融合矩阵分解和XGBoost的个性化推荐算法

针对传统的协同过滤推荐算法中评分矩阵过于稀疏和算法准确度不高的问题,提出一种融合矩阵分解和XGBoost算法的推荐算法(MFXGB,Matrix Factorization XGBoost),其特点是利用SVD++算法(SVD,Singular Value Decomposition)对用户项目评分矩阵进行填充,避免过多的缺失值对算法精确度的影响,再利用XGBoost(eXtreme Gradient Boosting)算法训练有监督的模型用于预测用户评分.为了克服计算成本过高的困难,提出利用K-均值聚类方法进行特征提取用于训练XGBoost模型.将MFXGB算法应用于MovieLens数据集进行实验分析,结果显示,MFXGB算法的推荐精确度比传统的3种方法分别提高了8.91％、10.18％和11.79％,效果明显优于传统的推荐算法.     

TdR诱导肝癌细胞株HepG2细胞周期同步化的效果

取对数生长期的 HepG2 细胞,加入含 TdR 的培养基 28 h 后,收集细胞,用 PBS 洗2次,加完全培养基,分别于 12 h 和24 h 收集各组细胞.用流式细胞术分析细胞周期各时相细胞百分数.探讨 TdR(胸腺嘧啶核苷)诱导人肝癌细胞株 HepG2 同步化后的细胞周期时相的变化.结果是TdR能较好地使肝癌细胞株Hepc2同步化于G1期和G2期.TdR诱导细胞后,分别于12中 h 获得(63.62±2.82)%的 G2/M 期同步化细胞,24 h 后获得(75.24±0.17)%的G1期同步化细胞.     

二维不规则贯通排样的模拟退火算法

提出一种获得不规则零件的最佳包络矩形的方法,根据矩形件的启发式算法,设计模拟退火智能算法将最佳包络矩形排样.模拟退火算法是全局优化概率的搜索算法,可以在优化排样中将排样次序优化,再利用最低水平线算法将不规则多边形排样.结果显示:同一排样问题,初始温度、冷却参数以及终止温度有一组最佳组合值,使得问题解的质量较高.该算法在排样效果和时间效率上更为优秀.     

人发中铬的色谱测定法准确度的研究

本文研究了发样制备过程中的误差来源,干、湿法制样所测得的发铬值相吻合,700℃高温下灼烧发样未见铬损失.讨论了不同酸度Htfa对Cr(Ⅲ)和Cr(Ⅵ)螯合效率的差异以及基体效应对发铬值测定准确度的影响,提高了解决方法,并用它测定了数批发样,混合发样平行测定的变异系数小于15％,个体发样小于10％.测定了NBS标样SRM 1570,含铬量为4.42±0.25μg/g(给定值4.6±0.3μg/g),平均回收率96.1％.     

华坪乌骨鸡产肉性能及肉质特性的研究初报

对放养并适量补饲的150日龄华坪乌骨鸡进行产肉性能、肉质特性、肉的常规营养成分及氨基酸含量进行测定.测定结果,其半净膛率、全净膛率、胸肌率、腿肌率、腹脂率,6分别为82.13±3.72％、69.47±3.03％、14.44±1.42％、24.46±0.69％、2.06±2.96％, 分别为82.15±3.20％、68.10±4.43％、16.18±3.72％、21.61±2.75％、5.03±4.21％;其肌肉(鲜样)水分、粗蛋白、粗脂肪、能量, 分别为75.5±0.6％、21.3±0.5％、2.2±0.4％、439.8±15.7 J/100g, 分别为73.9±1.2％、21.3±1.1％、3.4±13％、483.0±32.7 J/100g;其肌(鲜样)有17种氨基酸,总氨基酸、必需氨基酸、非必需氨基酸、必需/非必需, 分别为17402mg/100g、6663mg/100g、10739mg/100g、0.6204, 分别为17460mg/100g、6747mg/100g、10713mg/100g、0.6298;其肌肉pH值、嫩度、熟肉率、失水率, 分别为5.90±0.09、2.27±0.50kg、62.90±0.70％、40.13±4.52％, 分别为5.73±0.14、1.61±0.30kg、62.44±1.52％、38.69±6.80％.表明华坪乌骨鸡具有氨基酸种类齐全、营养丰富、低腹脂、低肌间脂肪、肉质细嫩等特点.     

一种改进的LDPC码译码算法

基于最小和译码算法,提出了一种改进算法,即在最小和译码算法的后期迭代中,采用尝试强制翻转最不可靠的比特位组的方法来提高译码性能.仿真结果表明,改进后的算法在信噪比1.4～2.2 dB时相对于改进前有0.3 dB的性能提高.     

MDCK单克隆细胞生长特性分析

目的:分析MDCK(犬肾细胞,Madin-Darby canine kidney cells,MDCK)单克隆细胞的生长特性,确定MDCK单克隆细胞库的可用性。方法:通过台盼蓝拒染测定细胞复苏活率,依据细胞生长的快慢、好坏和观察细胞形态判定细胞的生长速度、状态和形态.结果:MDCK单克隆细胞平均复苏活率为0.954±0.016,2～3 d长满的细胞占92.1%.57.9%的细胞生长状态良好,具有多角上皮样、梭形成纤维样和圆形岛状样三种形态.结论:MDCK单克隆细胞库中细胞复苏活率达到0.954±0.016,92.1%的单克隆细胞株在2～3 d长至单层致密,细胞状态良好.库内细胞有三种形态,可为病毒敏感细胞基质筛选提供丰富的资源。     

维不规则零件排样问题的粒子群算法求解

提出了一种基于粒子群算法求解二维不规则零件排样问题的方法.该方法首先将二维不规则零件的排样问题转化为矩形件的排样问题,然后利用粒子群算法优化求解,在求解过程中运用自适应调整策略对零件的排样位置进行微调.最后用该优化排样算法对文献中的两个算例求解,排样结果表明该算法是有效的.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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