水松的次生韧皮部解剖及其系统位置的讨论

在光学显微镜和扫描电子显微镜下观察，水松茎次生韧皮部的主要特征为：韧皮部由轴向系统和径向系统组成。轴向系统由筛胞、韧皮薄壁组织细胞、蛋白细胞和韧皮纤维组成，径向系统由韧皮射线组成。在横切面上，轴向系统的各组成分子以单层切向带交替有规律的排列，其排列顺序为：筛胞－韧皮薄壁组织细胞－韧皮纤维-筛胞。筛胞的径向壁上嵌埋有草酸钙结晶，韧皮纤维仅一种类型，韧皮射线同型、单列。根据水松茎次生韧皮部的解剖研究，并与杉科其它各属的有关资料进行比较，我们认为：水松属与水杉属和落羽杉属有较近的亲缘关系。     

日本农村工业化战略对托达罗模型的拓展研究

托达罗模型在一定程度上回答了发展中国家城乡发展中的乡-城人口流动的问题,但在解决发展中国家亟待迅速增加农民收入和保持工业发展低成本的两难境地时还存在不足。日本的农村工业化战略较好地解决了这一难题,将托达罗模型的两部门假设拓展为三部门,为发展中国家提供了统筹城乡发展的有效路径。     

扬子鳄心脏P物质免疫反应纤维和细胞的分布

用免疫组织化学法和异硫氰酸标记的间接免疫荧光方法观察了扬子鳄心脏内Ｐ物质免疫反应阳性神经纤维和细胞的分布。结果发现ＳＰ－ＩＲ纤维分布于心室、心房、静脉窦、主动脉瓣处;右心房见散在阳性细胞及神经节。ＩＲ纤维呈“串珠状”、线状或交织成网络状,主要分布于肌层及外膜,多伴血管走行。     

Solid-state intramolecular motions in continuous fibers driven by ambient humidity for fluorescent sensors

One striking feature of molecular rotors is their ability to change conformation with detectable optical signals through molecular motion when stimulated. However, due to the strong intermolecular interactions, synthetic molecular rotors have often relied on fluid environments. Here, we take advantage of the solid-state intramolecular motion of aggregation-induced emission (AIE) molecular rotors and one-dimensional fibers, developing highly sensitive optical fiber sensors that respond to ambient humidity rapidly and reversibly with observable chromatic fluorescence change. Moisture environments induce the swelling of the polymer fibers, activating intramolecular motions of AIE molecules to result in red-shifted fluorescence and linear response to ambient humidity. In this case, polymer fiber provides a process-friendly architecture and a physically tunable medium for the embedded AIE molecules to manipulate their fluorescence response characteristics. Assembly of sensor fibers could be built into hierarchical structures, which are adaptive to diverse-configuration for spatial-temporal humidity mapping, and suitable for device integration to build light-emitting sensors as well as touchless positioning interfaces for intelligence systems.     

Quantitative impedimetric monitoring of cell migration under the stimulation of cytokine or anti-cancer drug in a microfluidic chip

Cell migration is a cellular response and results in various biological processes such as cancer metastasis, that is, the primary cause of death for cancer patients. Quantitative investigation of the correlation between cell migration and extracellular stimulation is essential for developing effective therapeutic strategies for controlling invasive cancer cells. The conventional method to determine cell migration rate based on comparison of successive images may not be an objective approach. In this work, a microfluidic chip embedded with measurement electrodes has been developed to quantitatively monitor the cell migration activity based on the impedimetric measurement technique. A no-damage wound was constructed by microfluidic phenomenon and cell migration activity under the stimulation of cytokine and an anti-cancer drug, i.e., interleukin-6 and doxorubicin, were, respectively, investigated. Impedance measurement was concurrently performed during the cell migration process. The impedance change was directly correlated to the cell migration activity; therefore, the migration rate could be calculated. In addition, a good match was found between impedance measurement and conventional imaging analysis. But the impedimetric measurement technique provides an objective and quantitative measurement. Based on our technique, cell migration rates were calculated to be 8.5, 19.1, and 34.9 μm/h under the stimulation of cytokine at concentrations of 0 (control), 5, and 10 ng/ml. This technique has high potential to be developed into a powerful analytical platform for cancer research.     

Translocation of nanoparticles through a polymer brush-modified nanochannel

A basic understanding of the transport mechanisms of nanostructures in a polymer brush-modified nanochannel as well as the brush-nanostructure interactions at molecular level is important to design and fabricate emerging smart nano/microfluidic channels. In this work, we report coarse-grained molecular dynamics simulations of the translocation of nanoparticles through a cylindrical nanochannel coated with the polymer brush. The effects of the interparticle interaction and grafting density on the distribution and electrokinetic transport of nanoparticles are addressed in detail. Analysis of the distribution and velocity profiles of nanoparticles from the simulations indicate that the location of nanoparticles along the radial direction and their migration velocity are very sensitive to the change of interparticle interaction. We find complicated transport dynamics of nanoparticles under the influence of various grafting densities. The nanoparticles show markedly different translocation behavior upon increasing the grafting density, which depends on the counterion distribution, free room within the brush, nanoparticle-polymer friction, and brush configuration. Our results may serve as a useful starting point for the transport of nanostructures in polymer-modified channels and help to guide the design of novel smart nanofluidic channels for controlling the migration behavior of nanostructures.     

古紫萁属的订正及两个新种

The genus Palaeosmunda was established by R. E. Gould in 1970 based upon some  Late Permian Osmundaceous trunks with well-developed leaf gaps and rhomboidal  sclerotic ring within petiolar base seen in cross section.  As he thinks that the latter  character is more important than the former, this genus could not be assigned to any  subfamily of Osmundaceae.        However, the leaf gap is one of the most important characters in the structure of the fern stem, so the author suggests that this genus should be assigned to subfamily  Osmundoideae and its diagnosis must be emended as follows:       The genus Palaeosmunda is represented by some rhizomes (or trunks), roots and leaf bases of ferns which structurally are preserved,  resembling  Osmundacaulis  but which can’t be assigned to any group of this genus.        Stem containing an ectophloic dictyoxylic siphonostele; if tracheids present in  the pith, they being multiseriate scalariform pitted; pith or cortex sometimes contain-  ing groups of secretory cells or sclerenchyma; number of leaf traces seen in a tran-   sverse section of cortex more than 30; leaf traces adaxially curvature, rarely oblong-  shaped; petiolar bases with or without stipular  expansion,  containing  a C-shaped vascular strand; root diarch.       Type species——Palaeosmunda williamsii.      According to this diagnosis some primitive osmundaceous species with the  leaf gaps, which have already found in Upper Permian and Lower Triassic, could be assigned to this genus.  Two of them are P. williamsii Gould and P. playfordii Gould, and Osmundacaulis beardmorensis, which was from Lower Triassic of Antarctica in 1978, should be assigned to the genus Palaeosmunda.      In this paper two osmundaceous new species: P. primitiva and P. plenasioides were found in the coal balls of Upper Permian age  from  Wangjiazhai  of  Shuicheng  of Guizhou Province, China.       P. primitiva is represented by two trunks; stem about  4 cm in diameter;  stele actophloic dictyoxylic siphonostele; pith cavity about 3—4 mm in diameter, contianing parenchyma and tracheids; xylem cylinder thin, less than 10 tracheids in radial thick- ness, dissected by leaf gaps.  Inner cortex about 1.5 cm thick, mainly parenchymatous, but sometimes containing a few sclerenchymatous; number of leaf traces seen in a transverse section about 50—60; leaf traces departing at 35—45º,open C-shaped at point of departure, gradually becoming shallow C-shaped or V-shaped in different parts; protoxylem in base of leaf traces single, endarch; when leaf traces pass through inner cortex, protoxylem biturcating.  Petiole bases without stipular expansion, probablyloosely embracing the stem; xylem strand of potiole trace shallow C-shaped, surrounded by selerenchyma; sclerotic ring round, connected with single sclerenchyma mass in the concavity of the petiole trace.  Root arising singly from leaf trace, diarch, with inner and outer cortex.       P. plenasioides is represented by a rhizome; stem more than 4 cm in diameter; stele actophloic dictyoxylic siphonostele; xylem cylider with about 20  tracheids in radial thickness, dissected by leaf gaps; xylem bundle U-, O-, or crosier- (i.e. query-) shaped; pith and inner cortex parenchymatous, with many groups of secretory cells; leaf trace C-shaped, its base containing two endarch protoxylem groups; root diareh,with inner and outer cortex, arising singly from leaf trace or its base.     

成熟产业实现技术追赶的惯性传导路径研究

为解决后发国家制造业在国际范围内实现由产业链低端向高端迁移过程中,亟待解决的如何实现技术追赶问题。文章以我国成熟产业的典型企业为样本,采用扎根理论方法对后发国家实现技术追赶的过程进行研究,力图在后发国家的独特情景下,提炼具有潜在社会应有价值的研究结论。基于文章所提出的后发国家成熟产业实现技术追赶的惯性传导路径模型,研究发现:(1)与多数研究结论不同,惯性因素在特定条件下不是企业实现变革的阻碍因素,而是促进企业实现技术追赶的本源性推动因素;(2)在实现技术追赶的不同阶段,主导惯性呈现出不同的特性,并通过不同惯性间的交互作用,驱动技术追赶过程完成;(3)作为惯性贯穿技术追赶全过程。     

Depoliticizing the European immigration debate: How to employ public sector innovation to integrate migrants

Immigration is a hotly debated and politicized policy area, one in which governments confront fierce opposition from populist parties and negative media narratives altering citizens’ perceptions of the issue. There is also growing scholarly interest in migration; new migrant integration research advocates for a conceptual shift away from focusing on migrant populations and towards rethinking host communities. At the same time, public sector innovation research is developing new approaches for how governments and public organizations can be innovative in dealing with grand challenges such as migration. The aim of this article is to merge these two subfields in order to answer a guiding research question: how can public organizations be innovative to promote integration for migrants? We suggest a typology of different innovation strategies that governments can adopt regarding integration, and we present five illustrative cases from European nations to examine how governments can innovate in order to integrate migrants. We find that governments can use multiple tools to promote integration and respond to grand challenges; governments can use various sources of innovation to address major barriers to migrant integration (e.g. language barriers, negative media and public opinion, and the difficulties of providing concrete assistance).     

Regional Distribution of Copper,Zinc and Iron in Brain of Wistar Rat Model for Non-Wilsonian Brain Copper Toxicosis

In previous studies, we have reported first in vivo evidence of copper deposition in the choroid plexus, cognitive impairments, astrocytes swelling (Alzheimer type II cells) and astrogliosis (increase in number of astrocytes), and degenerated neurons coupled with significant increase in the hippocampus copper and zinc content in copper-intoxicated Wistar rats. Nonetheless, hippocampus iron levels were not affected by chronic copper-intoxication. Notwithstanding information on distribution of copper, zinc and iron status in different regions of brain due to chronic copper exposure remains fragmentary. In continuation with our previous study, the aim of this study was to investigate the effects of intraperitoneally injected copper lactate (0.15 mg Cu/100 g body weight) daily for 90 days on copper, zinc and iron levels in different regions of the brain using atomic absorption spectrophotometry. Copper-intoxicated group showed significantly increased cortex, cerebellum and striatum copper content (76, 46.8 and 80.7 % increase, respectively) compared to control group. However, non-significant changes were observed for the zinc and iron content in cortex, cerebellum and striatum due to chronic copper exposure. In conclusion, the current study demonstrates that chronic copper toxicity causes differential copper buildup in cortex, cerebellum and striatum region of central nervous system of male Wistar rats; signifying the critical requirement to discretely evaluate the effect of copper neurotoxicity in different brain regions, and ensuing neuropathological and cognitive dysfunctions.     

SGK、糖皮质激素及其受体在应激促进空间学习记忆中的作用

应激会对动物的学习记忆能力产生影响,这种影响呈一种倒U型关系,即当应激强度过大或时间过长时这种影响往往是一种损伤,而适度的应激会对学习记忆产生促进作用。目前认为应激激活了下丘脑-垂体-肾上腺（hypothalamo-pituitary-adrenal,HPA）轴,诱导糖皮质激素的释放。适量的糖皮质激素会促进长时程增强（long-term potentiation,LTP）的形成,从而促进学习记忆。血清/糖皮质激素诱导激酶（serum and glucocorticoid regulated protein kinase,SGK）作为糖皮质激素诱导的一个激酶,参与了多种离子通道的调节,能够促进神经元的存活和轴突的再生。研究发现SGK的表达也会促进空间学习记忆能力。     

Stresses in a radially constructed rotating cylinder

The dynamic radial stress distribution in a circular hollow cylinder, bonded to a rigid core at its inner surface and prevented from outward displacement by a smooth rigid cylindrical wall, due to a rotational motion with a variable angular velocity, is analyzed.The stress as a function of radial distance and time is determined. A sample calculation shows that the stress changes from tension at the inner surface to compression at the outer surface, as would be expected. The variation of stress vs radial distance is plotted for several instants of time. Also, the stress vs time for various radial positions is plotted.     

Microfluidic wet spinning of chitosan-alginate microfibers and encapsulation of HepG2 cells in fibers

The successful encapsulation of human hepatocellular carcinoma (HepG2) cells would greatly assist a broad range of applications in tissue engineering. Due to the harsh conditions during standard chitosan fiber fabrication processes, encapsulation of HepG2 cells in chitosan fibers has been challenging. Here, we describe the successful wet-spinning of chitosan-alginate fibers using a coaxial flow microfluidic chip. We determined the optimal mixing conditions for generating chitosan-alginate fibers, including a 1:5 ratio of 2% (w∕w) water-soluble chitosan (WSC) solution to 2% (w∕w) alginate solution. Ratio including higher than 2% (w∕w) WSC solution increased aggregation throughout the mixture. By suspending cells in the WSC-alginate solution, we successfully fabricated HepG2 cell-laden fibers. The encapsulated HepG2 cells in the chitosan-alginate fibers were more viable than cells encapsulated in pure alginate fibers, suggesting that cross-linked chitosan provides a better environment for HepG2 cells than alginate alone. In addition, we found that the adhesion of HepG2 cells on the chitosan-alginate fiber is much better than that on the alginate fibers.     

Microfluidic platform integrated with worm-counting setup for assessing manganese toxicity

We reported a new microfluidic system integrated with worm responders for evaluating the environmental manganese toxicity. The micro device consists of worm loading units, worm observing chambers, and a radial concentration gradient generator (CGG). Eight T-shape worm loading units of the micro device were used to load the exact number of worms into the corresponding eight chambers with the assistance of worm responders and doorsills. The worm responder, as a key component, was employed for performing automated worm-counting assay through electric impedance sensing. This label-free and non-invasive worm-counting technique was applied to the microsystem for the first time. In addition, the disk-shaped CGG can generate a range of stepwise concentrations of the appointed chemical automatically and simultaneously. Due to the scalable architecture of radial CGG, it has the potential to increase the throughput of the assay. Dopaminergic (DAergic) neurotoxicity of manganese on C. elegans was quantitatively assessed via the observation of green fluorescence protein-tagged DAergic neurons of the strain BZ555 on-chip. In addition, oxidative stress triggered by manganese was evaluated by the quantitative fluorescence intensity of the strain CL2166. By scoring the survival ratio and stroke frequency of worms, we characterized the dose- and time-dependent mobility defects of the manganese-exposed worms. Furthermore, we applied the microsystem to investigate the effect of natural antioxidants to protect manganese-induced toxicity.     

轮钟花属的恢复及其花粉和种皮证据

光学显微镜和扫描电镜观察表明,金钱豹属(广义)花粉明显分为两个类型:Campanumoea inflata和C.javanica subsp.laponica的花粉5～8沟,外壁具相对密的短刺,刺高不过1μm,而C.lancifolia,C.celebica和C.parviflora的花粉3孔沟,外壁刺稀疏,高于2μm。种子表面纹饰也同样可分为  两类,前两个种一类,其种子表面网状,网眼规则而多角形,直径大于网脊宽度,网脊上的次级纹饰为念  珠状,而后三种为一类,其种子表面网眼不规则,直径与网脊宽度近相等,网脊上的次级纹饰绳索状。可  见花粉特征与种皮性状是高度相关的。后三个种所属的分类群就是被归并了的属Cyclocodon Griffith。  综合花粉、种皮及外部形态,这个属应予恢复。其近缘属应是Platycodon,而不是Campanumoea。     

我国区域税收转移的成因与影响

目前中国存在税收与税源背离现象,税收转移大致呈现出由经济欠发达地区向发达地区转移的特征。其原因是：企业汇总纳税、总部经济、省际贸易、资源性产品价格扭曲、税制设计不尽合理、区域间税收竞争、税收政策区域差异、集团公司转让定价、隐形的税收转移、内外资企业迁移。税收与税源的背离,会减少地方财力,加剧地区差距,降低经济效率,不利于保护资源和改善投资环境,影响政府形象与科学决策。对此,要树立科学税收观,建立与完善税收分配体制,促进经济可持续发展。     

基于径向基函数网络的改进算法的股市数据预测

径向基函数网络的性能在很大程度上取决于径基函数中心位置的选取。本文通过结合输入输出矢量从而得到扩展矢量的方式改进了常用的确定径基函数中心的HCM算法。股市数据预测的实验结果表明：改进的HCM算法的网络的性能有了明显的改善。     

Correlation between cell migration and reactive oxygen species under electric field stimulation

Cell migration is an essential process involved in the development and maintenance of multicellular organisms. Electric fields (EFs) are one of the many physical and chemical factors known to affect cell migration, a phenomenon termed electrotaxis or galvanotaxis. In this paper, a microfluidics chip was developed to study the migration of cells under different electrical and chemical stimuli. This chip is capable of providing four different strengths of EFs in combination with two different chemicals via one simple set of agar salt bridges and Ag/AgCl electrodes. NIH 3T3 fibroblasts were seeded inside this chip to study their migration and reactive oxygen species (ROS) production in response to different EF strengths and the presence of β-lapachone. We found that both the EF and β-lapachone level increased the cell migration rate and the production of ROS in an EF-strength-dependent manner. A strong linear correlation between the cell migration rate and the amount of intracellular ROS suggests that ROS are an intermediate product by which EF and β-lapachone enhance cell migration. Moreover, an anti-oxidant, α-tocopherol, was found to quench the production of ROS, resulting in a decrease in the migration rate.     

土地确权与农村劳动力迁移——来自省级面板数据的证据

关于土地确权会促进还是抑制农村劳动力迁移,现有研究尚无定论。本文构建理论模型,将土地确权对劳动力迁移的影响分解为失地风险降低效应和土地投资激励效应,利用2005—2019年中国30个省份的面板数据和双向固定效应模型,从宏观视角对二者关系进行检验;在此基础上,引入面板门槛模型探讨该影响效果在不同土地流转市场发展水平下的异质性。结果表明：①中国土地确权主要发挥了失地风险降低效应,有助于促进农村劳动力向外迁移,尤其是对常年外出和省外迁移的促进效应更大。②土地确权对劳动力迁移的促进作用在东部和南方地区较强,而在中、西部和北方地区则不显著。③土地确权对劳动力迁移的影响存在以土地流转市场发展水平为前提的门槛效应,当土地流转市场发展水平较低时,确权对劳动力迁移无显著影响;只有当土地流转市场发展水平达到一定门槛值后,确权才会对劳动力迁移起到显著促进作用。本文的政策含义在于,要以确权推动农业剩余劳动力城市化迁移,除了明晰产权以外,还须同步推进土地流转市场建设。     

Multi-function microsystem for cells migration analysis and evaluation of photodynamic therapy procedure in coculture

Cell migration is an important physiological process, which is involved in cancer metastasis. Therefore, the investigation of cell migration may lead to the development of novel therapeutic approaches. In this study, we have successfully developed a microsystem for culture of two cell types (non-malignant and carcinoma) and for analysis of cell migration dependence on distance between them. Finally, we studied quantitatively the influence of photodynamic therapy (PDT) procedures on the viability of pairs of non-malignant (MRC5 or Balb/3T3) and carcinoma (A549) cells coculture. The proposed geometry of the microsystem allowed for separate introduction of two cell lines and analysis of cells migration dependence on distance between the cells. We found that a length of connecting microchannel has an influence on cell migration and viability of non-malignant cells after PDT procedure. Summarizing, the developed microsystem can constitute a new tool for carrying out experiments, which offers a few functions: cell migration analysis, carcinoma and non-malignant cells coculture, and evaluation of PDT procedure in the various steps of cell migration.