435 research outputs found

    Research on Relation between Real Estate and Inflation in China

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    我国从1998年开始在制度上建立市场化住房体制,并提出了要把房地产业培育成为国民经济的支柱产业。自此房地产业开始进入快速发展时期,与之相伴,房价也呈现出一路飙升的势头。同时,随着资本市场的不断膨胀,房地产也已不再仅仅是消费品,更成了重要的投资品。 文章从分析房地产与通货膨胀的相关关系入手,研究了房地产行业对国民经济的带动效用、房地产作为一种资产自身的保值功能,同时通过详尽考察房地产价格波动对企业投资、消费以及货币供求的影响,揭示房地产价格波动影响通货膨胀的机制和渠道。这部分的分析为实证研究奠定了理论基础。 进一步,论文对改革开放后我国房地产市场化的发展历程进行了回顾,对这段时期国内出现的几...Housing system reform has begun institutional since 1998 in China, and real estate was aimed to be the mainstay industry of national economy. From then on, real estate is in a rapid growth stage while the housing price is sky-rocketing accordingly. At the same time, real estate is not only consumer goods, but also important investment item with the ever-expanding of the capital market. On one han...学位:经济学硕士院系专业:经济学院计划统计系_统计学学号:2005130075

    Inulin Molecular Detection Methods of High-Performance Gel FiltrationChromatography and Changes in Inulin Molecular Weight During Storage

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    菊芋是一种耐盐抗旱植物,可用于生产菊糖.菊糖具有良好的生物活性,其活性受到聚合度的影响.本研究对比了各项条件,总结得到了一套可以用于测定菊糖相对分子量的高效凝胶过滤色谱(HPGFC)方法:纯水为流动相,0.8 m L/min洗脱,Shodex OHpak SB-804HQ色谱柱检测,柱温控制在30℃,样品进样量为每次20μL,检测器为示差折光检测器(RID),采用Sigma公司生产的右旋糖酐标准品,绘制二次方的标准曲线,检测菊糖的相对分子质量.同时利用确定的凝胶过滤色谱(GFC)方法,观察了种植于海岸带盐碱地的菊芋块茎采收后在贮藏过程中的菊糖分子量的变化,发现在?20℃的贮藏条件下,菊芋中的菊..

    Shunting Economic Law:a Gradually Changing System Model——From the View of Thirty Years' Developing Course of Economic Law

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    我国经济法肇始于1978年改革开放的巨大变革时代,立足于我国转型经济的现实土壤,历经“有计划商品经济“到市场经济的跃迁,在我国波澜壮阔的经济体制改革进程中成长壮大。自身成长壮大的需要和社会经济变革的需求,都注定它必须面向不断试错的、渐进的社会转型需要,回应和影响市场经济跌宕起伏的动态进程,呈现一种渐进的制度变迁模式,在完成型塑我国社会经济的过程中发展、嬗变和成熟。Our country's economic law started at the policy of reform and opening-up time in 1978,based on the realistic background of economic system reform,went through "planned commodity economy" to market economy,grow up following the our country's magnificent economic system reform.The need of economic law's growing up and the need of social and economic reform makes it face to the gradual social reform need,reflect and inference the dynamic progress of market economy,show itself as a gradually changing system model,develop,change and become mature in the process of modeling our country's social economy

    The Role of Microorganisms in the Geochemical Iron Cycle

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    铁元素虽然只在地壳含量中位列第4,但却是地球上分布最广的变价金属元素之一,微生物介导的铁循环及其与生源要素碳、氮、氧和硫等耦合的氧化还原反应是微生物地球化学循环的重要驱动力.由于铁循环过程中氧化态三价铁Fe(Ⅲ)在环境p H条件下大多以不溶状态存在,因而由其参与的地球化学循环进程通常较为缓慢.研究表明,微生物在铁元素的地球化学循环过程中起着举足轻重的作用,并在该过程中参与矿物的生成与转化.近年来的最新研究发现,参与地球化学铁循环的微生物之间,微生物与矿物之间,以及矿物介导的微生物之间存在着多样的相互作用,而含铁矿物介导的微生物胞外电子传递机制是其中最受瞩目的研究热点.本文综述了微生物介导的地球..

    区域医疗物联网监管平台总体规划与设计

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    目的:解决当前医疗物联网应用中顶层设计缺乏和标准不统一的问题,加强医疗物联网数据监管,充分利用物联网可穿戴设备采集的数据,辅助医生及时有效地进行疾病预防干预和治疗。方法:采用Hadoop、REST、Hbase等关键技术,构建区域医疗物联网监管平台,实现健康监护,并以厦门慢病全程健康管理为切入点进行应用与实践。结果:医疗物联网监管平台在厦门全程慢病管理中的成功应用,能有效辅助基层医疗卫生机构管理者进行监管决策,辅助家庭医生进行健康照护,提升了居民的满意度与家庭医生的服务存在感。结论:区域医疗物联网监管平台能够为医院管理者和医务人员提供有效的健康数据支撑,辅助医务人员为患者提供个性化的预防和治疗解决方案,提升医疗服务水平与居民的满意度

    Redistribution of iron during directional solidification of metallurgical-grade silicon at low growth rate

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    研究冶金级硅低速定向凝固过程中杂质铁的再分布。采用ICP-MS检测铁的浓度,绘制铁在固相、液相、晶界和晶体生长方向上的浓度示意图。铁浓度在固、液相中具有明显差异。依据质量守恒定理,计算得出溶质边界层约为4 mm,铁的有效分凝系数约为2.98×10~(-4)。在低速凝固条件下,铁容易偏析聚集在晶界。在生长方向上,由于低速凝固,铁浓度在硅锭86%高度以下几乎恒定,不完全符合Scheil方程规律。讨论了对流对铁再分布的影响,对流"死区"对铁再分布具有重要影响。Redistribution of iron during directional solidification of metallurgical-grade silicon(MG-Si) was conducted at low growth rate. Concentrations of iron were examined by ICP-MS and figured in solid and liquid phases, at grain boundary and in growth direction. Concentrations are significantly different between solid and liquid phases. The thickness of the solute boundary layer is about 4 mm verified by mass balance law, and the effective distribution coefficient is 2.98×10~(-4). Iron element easily segregates at grain boundary at low growth rate. In growth direction, concentrations are almost constant until 86% ingot height, and they do not meet the Scheil equation completely, which is caused by the low growth rate. The effect of convection on the redistribution of iron was discussed in detail. Especially, the "dead zone" of convection plays an important role in the iron redistribution.Projects(51334004,51204143)supported by the National Natural Science Foundation of China;; Project(2006L2003)supported by the Scientific Technological Innovation Platform of Fujian Province,Chin

    中国黏膜黑色素瘤的临床特点及基因突变分析

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    【目的】采用二代测序(NGS)检测黏膜黑色素瘤中的295个基因突变情况,分析黏膜黑色素瘤患者的基因突变谱及突变特点,探索潜在治疗靶点。【方法】组织标本来自2017年9月至2018年9月在中山大学肿瘤防治中心生物治疗科就诊的黏膜黑色素瘤患者,于我院分子诊断科行NGS检测295个基因变异。【结果】黑色素瘤主要驱动基因突变频率分别为BRAF20%(5/25),KIT20%(5/25),NRAS12%(3/25),NF18%(2/25)。最常见的基因突变为MYC拷贝数增加(36%,9/25),其次为KDR拷贝数增加,突变率为24%(6/25)。DNA损伤修复,细胞周期,PI3K-mTOR,生长因子受体,MAPK,免疫应答和WNT/NOTCH相关通路广泛存在突变,突变率分别为76%(19/25),72%(18/25),56%(14/25),60%(15/25),36%(9/25),28%(7/25),24%(6/25)。可见多个靶向治疗靶点,如ATM,ATRX,EMSY,FANCI,RAD52,MET,PDGFRA,KDR,FLT4,ALK,ERBB3及ROS1等。【结论】中国黏膜黑色素瘤基因突变谱与皮肤型存在差异,且与西方人群不同,NGS测序可为黏膜黑色素瘤的治疗提供潜在治疗靶点

    High-precision measurements of Fe and Zn isotopic ratios in marine sediments

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    介绍海洋沉积物fE和zn同位素化学前处理及测定方法,报道南海西部夏季上升流区两个沉积物柱样的fE和zn同位素组成。样品采用Hf+HnO3+HClO4常压消解,经脱盐后,转化为氯化物形式并经离子交换柱分离纯化后,用多接收器等离子体质谱法测定fE和zn同位素比值。该前处理方法可以快捷地实现海洋沉积物的消解、有机质的去除和海盐脱离;结合相关测试流程,可获得较高的δ56fE(0.10‰,2Sd)和δ66zn分析精度(0.11‰,2Sd)。两个沉积物柱样的δ56fE值(相对于IrMM-014)和δ66zn值(相对于JMC3-0749C)随深度变化不明显,两柱之间也无明显差异。总体上,南海西部上升流区1~2 kA以来的沉积物δ56fE值(0.04‰~0.20‰)和δ66zn值(0.12‰~0.30‰)与已报道的黄土和气溶胶、火成岩以及大部分海洋沉积物接近,明显高于静海相海洋沉积物的δ56fE值。We present an optimized chemical separation and purification procedure as well as an analytical method for measuring Fe and Zn isotopic composition in marine sediments.We also report Fe and Zn isotopic compositions in two sediment cores with an age of 1-2 ka from the summer upwelling region in the western South China Sea.Samples were dissolved with an acid solution(HF + HNO3 + HClO4) under normal pressure,followed by desalination and transformation to chloride matrix.After separation and purification,Fe and Zn isotopic ratios were determined with a Nu Plasma HR MC-ICPMS.Results demonstrate that this chemical preparation can rapidly dissolve marine sediments,remove organic matter,and,in combination with this analytical technique,we achieved high analytical precisions of 0.10‰ for δ56Fe(2SD) and of 0.11‰ for δ66Zn(2SD).These two sediment cores had nearly invariant δ56Fe and δ66Zn values throughout the sediment cores.Moreover,δ56Fe(0.04‰-0.20‰) and δ66Zn(0.12‰-0.30‰) from these 1-2 ka marine sediments are overall close to those reported for loesses and aerosols,igneous rocks and other marine sediments worldwide,but much higher than those deposited in euxinic environments.国家自然科学基金创新群体项目(40921001;40521003);国土资源部公益性行业研究专项经费项目(201011027

    PD-1 抗体联合替莫唑胺治疗晚期黑色素瘤的疗效及安全性分析

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    【目的】探讨PD-1抗体联合替莫唑胺治疗晚期黑色素瘤患者的疗效与安全性。【方法】回顾性分析2017年8月至2019年4月在中山大学肿瘤防治中心接受PD-1抗体联合替莫唑胺方案治疗的晚期恶性黑色素瘤患者33例,具体方案为:PD-1抗体[Pembrolizumab2mg/kg,每3周为一个周期;或Nivolumab3mg/kg,每2周为一个周期;或Toripalimab3mg/kg,每2周为一个周期]联合替莫唑胺[200mg(/m2·d),连续口服5d,每28d为一个周期;或75mg(/m2·d),连续口服21d,每28d为一个周期],至少2个周期(以替莫唑胺周期为准,下同)后评价疗效。应用RECISTv1.1标准评价疗效,不良事件按照NCI-CTCAE4.0分级。【结果】33例患者接受的中位疗程数为替莫唑胺6.0(1~12)个周期和PD-1抗体7.0(1~27)个周期,客观有效率(ORR)为24.2%(肢端型ORR为38.5%),疾病控制率(DCR)为60.6%,中位无进展生存期(mPFS)为4.3月(95%CI,1.3~7.3),中位疾病控制时间(mDDC)为7.5月(95%CI,2.3~12.7),中位缓解持续时间(mDOR)为11.1月(95%CI,5.5~16.6),中位总生存(mOS)尚未达到,1年生存率为86.1%。Kaplan-Meier法生存分析和COX多因素分析均显示影响PFS的因素有PD-L1表达和BARFV600E/K基因突变状态。PD-L1表达阳性患者比阴性患者有更长的PFS(0.05)。常见不良反应包括皮肤瘙痒(30.3%)、皮疹(21.2%)、疲劳(21.2%)、恶心(21.2%)、呕吐(15.2%)、转氨酶升高(15.2%)、胆红素升高(9.1%)等,绝大多数均为1~2级。【结论】PD-1抗体联合替莫唑胺治疗晚期黑色素瘤近期疗效优于单用,尤其是对于肢端型黑色素瘤,安全性高,可在临床进行更加深入的研究和应用

    笔谈:文史结合的现代学术意义

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    20 0 3年 9月 1 9日 ,南京大学中文系和古典文献研究所在该校知行楼召开了“文史结合的现代学术意义”研讨会。本刊顾问卞孝萱先生作了主题发言 ,与会专家学者进行了热烈讨论。今将本刊在会内会外收集的意见 ,摘要刊出 ,以飨读者
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