The pre-raphaelites and science

Classic voltaic batteries of the silver/zinc and copper/zinc types are the ancestors of today's primary cells, and facilitated the development of many aspects of electrical technology. Nevertheless, they appear never to have been studied and evaluated in a quantitative manner, with results recorded in terms of volts, amps, ohms, and watts. Research of this nature is reported here, and has been conducted for the most part with copper/zinc cells. Log–log graphs of voltage versus load and current, and power versus load, are presented for many electrolyte systems. It has been shown that, although the textbook electrolyte of dilute sulphuric acid does work, it is an order of magnitude inferior to a solution containing some additional nitric acid. The latter diminishes the current‐limiting phenomenon of polarization, and was in fact used by Davy, Faraday, and other early investigators. A quantitative consideration of Nicholson and Carlisle's discovery of the electrolysis of water with a silver/zinc voltaic pile is followed by examination of the electrolysis of pure water, trough batteries, and Davy's isolation of potassium and sodium. Every battery gives maximum power when its resistance is adjusted (by appropriate series/parallel connections) to match the resistance of the load: the maximum output of the ‘Great Battery’ of the Royal Institution is assessed at no more than 3 kW. The paper concludes with a note on the recognized hazard of long‐term exposure to mercury vapour (produced by amalgamation of zinc electrodes in batteries) and its possible relevance to the health of Michael Faraday.     

磁流体-泡沫金属减振器磁路优化设计

利用ANSYS软件对磁流体-泡沫金属减振器的磁路进行数值模拟研究,对影响其性能的磁路级数及相邻两级线圈中电流流向的异同进行了分析.研究结果表明,相同条件下采用多级磁路较单级磁路具有较多的优点,并且多级磁路中相邻激励线圈绕向相反能够更好的改善磁路性能.本研究为磁流体-泡沫金属减振器的设计提供依据.     

History and scientific practice in the construction of an adequate philosophy of science: revisiting a Whewell/Mill debate

William Whewell raised a series of objections concerning John Stuart Mill’s philosophy of science which suggested that Mill’s views were not properly informed by the history of science or by adequate reflection on scientific practices. The aim of this paper is to revisit and evaluate this incisive Whewellian criticism of Mill’s views by assessing Mill’s account of Michael Faraday’s discovery of electrical induction. The historical evidence demonstrates that Mill’s reconstruction is an inadequate reconstruction of this historical episode and the scientific practices Faraday employed. But a study of Faraday’s research also raises some questions about Whewell’s characterization of this discovery. Thus, this example provides an opportunity to reconsider the debate between Whewell and Mill concerning the role of the sciences in the development of an adequate philosophy of scientific methodology.     

Intermediate filament assembly: temperature sensitivity and polymorphism

Intermediate filament (IF) proteins are encoded by a large multigene family and form polymers with a uniform diameter of approximately 10 nm. However, although the cytoplasmic representatives all confirm to a unit-type structural principle leading to the formation of extended coiled coils, it is becoming increasingly clear that subunit arrangements and physical properties vary among the different filaments. Thus, the intricate tissue-specific expression pattern of individual IF proteins (especially, their co-expression with other members of the IF protein family or with IF-associated proteins to form obligatory heteropolymers) points to distinct functions acquired during evolution relevant to cellular homeostasis in various tissues.     

Unipolar induction: a case study of the interaction between science and technology

Unipolar induction, discovered in 1832 by Michael Faraday, is the case of electromagnetic induction in which a conductor and magnet are in relative rotatory motion. Attempts by scientists and engineers in the nineteenth and twentieth centuries to understand unipolar induction by using magnetic lines of force displayed striking national differences that influenced where the first largescale unipolar dynamo was built. This episode is described, as well as the effect of unipolar induction on Albert Einstein's thinking toward the special theory of relativity, in sections 1–6. The analysis of electromagnetic induction in cases where the source of the magnetic field is in motion relative to the conductor is provided in sections 7–9.     

能源互联网重要基础支撑:分布式储能技术的探索与实践

可再生能源分布式发电的能量波动性以及用户驱动的能量需求的时空随机性,导致能源互联网中能量流本身具有先天的不确定性与无秩序性,因此,分布式储能技术由于可以有效消除能量流的不确定性,并使能量的时空转移和能量流的有序流动成为可能,成为能源互联网重要基础支撑.分布式电池储能作为一种重要的储能方式,电池单体本身非线性特性与电池成组或成网后单体间的差异性,使得电池储能系统"管理好"成为真正"使用好"的基础.但是,电池成组或成网后将构成复杂巨系统,这对"管理好"带来巨大的挑战.因此,本文基于作者多年理论与技术的成果积累,总结了一套适用于分布式储能的大规模电池网络优化管理的理论与方法,包括:单体和电池组或电池网络的建模与状态参数精确估算;基于模糊测度的电池网络特征提取及快速计算;基于自适应动态规划的电池网络优化管理.随后,本文将基于能源互联网思想的分布式储能架构及其管理优化方法与技术引入数据中心,并给出了其在数据中心中实际应用原型系统介绍.本文工作可以为能源互联网的重要基础支撑—分布式储能技术—的研究与应用提供方法指导与技术支撑.     

引种植物水竹芋捕虫行为的初步观察研究

通过对引种植物水竹芋的观察,发现水竹芋的花具有捕捉昆虫的能力,在此基础上对其花进行了解剖结构特征和捕虫行为的观察,并初步探讨了其捕虫行为的生态学意义.观察研究显示,水竹芋开放花以及即将开放花的花柱具有较强的卷曲能力;未开放以及开放后没有被触及的花的花柱被兜状退化雄蕊包被;当昆虫进入饰变雄蕊群形成的筒状结构而触及到兜状退化雄蕊时,花柱因产生应激反应而迅速卷曲,从而将昆虫捕捉.初步观察研究认为,水竹芋不仅具有捕捉昆虫的能力,而且在水污染处理以及湿地的恢复与重建中具有重要的应用潜力.     

Maxwell’s contrived analogy: An early version of the methodology of modeling

The term “analogy” stands for a variety of methodological practices all related in one way or another to the idea of proportionality. We claim that in his first substantial contribution to electromagnetism James Clerk Maxwell developed a methodology of analogy which was completely new at the time or, to borrow John North’s expression, Maxwell’s methodology was a “newly contrived analogue”. In his initial response to Michael Faraday’s experimental researches in electromagnetism, Maxwell did not seek an analogy with some physical system in a domain different from electromagnetism as advocated by William Thomson; rather, he constructed an entirely artificial one to suit his needs. Following North, we claim that the modification which Maxwell introduced to the methodology of analogy has not been properly appreciated. In view of our examination of the evidence, we argue that Maxwell gave a new meaning to analogy; in fact, it comes close to modeling in current usage.     

熊野藻属Kumanoa系统分类研究进展

熊野藻属(Kumanoa)是淡水红藻中基于rbcL和SSU基因序列建立的一个属,并进一步得到了cox1和UPA序列结果的支持,隶属于串珠藻目(Batrachospermales)。本文综述了熊野藻属系统分类及我国该属植物研究的研究进展,对其主要形态特征进行了界定。该属植物与串珠藻属植物形态结构相似,但果孢子体通常半球形,位于轮节中央,受精丝长度有限,果胞枝弯曲、扭曲或螺旋状,其细胞形状明显区别于营养细胞。分子数据显示其单独聚为一支,明显区别于串珠藻属的类群。中国淡水熊野藻属已记录的种类有10种。利用分子生物学手段对我国淡水熊野藻属进行深入系统的、多特征的分类研究是今后该属植物的主要研究方向。     

Perception and description of New World non-human primates in the travel literature of the fifteenth and sixteenth centuries: a critical review

The current work presents the results of a review of most of the European diaries and travel chronicles containing reports of New World non-human primates dating from the discovery of America in 1492 until the end of the sixteenth century. We report the integral texts translated into English of these literary sources, giving a critical interpretation from a historical and scientific point of view. We note the ways these primates were perceived and described, with attention to the most important characteristics that were highlighted by the first explorers. Ethnotaxonomy and vernacular names used to designate non-human primates are also provided. This new body of knowledge, based largely on empirical reports full of details and first-hand observations, emerged as the first nucleus in the natural history of Neotropical Primates.     

锂离子电池失效的快速判定

通过锂离子单体电池的循环寿命实验,分析了该电池的充放电电流,电压以及内阻随循环次数的老化特性.研究发现,随着充放电次数的增加,电池在恒流阶段充入的容量占总容量的百分比的变化趋势和电池内阻变化相一致,因此可以根据恒流充电的时间来快速判定电池的衰减程度.     

Interactions among beans in neighboring Faraday cages

Summary Bean seeds, during their initial 4 h of absorption of water while in a Faraday cage, are able to interact mutually with similar absorbing beans in nearby Faraday cages. The interaction effects complementarity of response between adjacent cages to a common, fluctuating environmental factor affecting water uptake.This research was supported by a grant from the National Science Foundation, No. GB-41392X.     

Integral equations between theory and practice: the cases of Italy and France to 1920

In 1899, Ivar Fredholm discovered how to treat an integral equation using conceptual methods from linear algebra and use these ideas to solve certain classes of boundary value problems. He formulated a theory allowing him both to unify large classes of problems and to attack several problems fruitfully. The historical literature on the theory of integral equations has concentrated largely on the unification that was afforded by Hilbert and his school, but has not throughly investigated the roots of the subject in the older theory of partial differential equations, as developed for instance by Fredholm himself but also by Volterra and Levi-Civita. By concentrating on work issuing from this older tradition, in particular on French and Italian work, the paper shows how the new theory of integral equations was enthusiastically received, especially for its fruitful applications to areas of mathematical physics such as hydrodynamics, elasticity, and heat theory.     

Antony van Leeuwenhoek's microscopes and other scientific instruments: new information from the Delft archives

This paper discusses the scientific instruments made and used by the microscopist Antony van Leeuwenhoek (1632–1723). The immediate cause of our study was the discovery of an overlooked document from the Delft archive: an inventory of the possessions that were left in 1745 after the death of Leeuwenhoek's daughter Maria. This list sums up which tools and scientific instruments Leeuwenhoek possessed at the end of his life, including his famous microscopes. This information, combined with the results of earlier historical research, gives us new insights about the way Leeuwenhoek began his lens grinding and how eventually he made his best lenses. It also teaches us more about Leeuwenhoek's work as a surveyor and a wine gauger.

A further investigation of the 1747 sale of Leeuwenhoek's 531 single lens microscopes has not only led us to the identification of nearly all buyers, but also has provided us with some explanation about why only a dozen of this large number of microscopes has survived.     

William Thomson's dynamical theory: An insight into a scientist's thinking

William Thomson, later Lord Kelvin, played a major role in the nineteenth century in changing scientific theory from the statical view, associated with imponderables, to the dynamical view which conceived of energy as a separate and convertible entity. Thomson's conversion from the statical to the dynamical view of nature was due to the influence of experimentalists, Michael Faraday and James Prescott Joule. It was Thomson's use of mathematical metaphor that enabled him to interpret on a theoretical level the physical explanation given by Faraday and Joule.     

Functional characterization of CP148, a novel key component for centrosome integrity in Dictyostelium

The Dictyostelium centrosome consists of a layered core structure surrounded by a microtubule-nucleating corona. A tight linkage through the nuclear envelope connects the cytosolic centrosome with the clustered centromeres within the nuclear matrix. At G2/M the corona dissociates, and the core structure duplicates, yielding two spindle poles. CP148 is a novel coiled coil protein of the centrosomal corona. GFP-CP148 exhibited cell cycle-dependent presence and absence at the centrosome, which correlates with dissociation of the corona in prophase and its reformation in late telophase. During telophase, GFP-CP148 formed cytosolic foci, which coalesced and joined the centrosome. This explains the hypertrophic appearance of the corona upon strong overexpression of GFP-CP148. Depletion of CP148 by RNAi caused virtual loss of the corona and disorganization of interphase microtubules. Surprisingly, formation of the mitotic spindle and astral microtubules was unaffected. Thus, microtubule nucleation complexes associate with centrosomal core components through different means during interphase and mitosis. Furthermore, CP148 RNAi caused dispersal of centromeres and altered Sun1 distribution at the nuclear envelope, suggesting a role of CP148 in the linkage between centrosomes and centromeres. Taken together, CP148 is an essential factor for the formation of the centrosomal corona, which in turn is required for centrosome/centromere linkage.     

Enhancement of the cytogenetic efficacy of the antitumor agent bleomycin by the calcium and calmodulin antagonist fendiline

The induction of chromosome aberrations (dicentric and ring chromosomes) in human lymphocytes by the antitumor agent bleomycin is synergistically enhanced when bleomycin is applied together with the calcium antagonist fendiline (Sensit).     

Resetting epigenetic signatures to induce somatic cell reprogramming

Somatic cell reprogramming consists of the induction of a complex sequence of events that results in the modification of the developmental state of the cell. It is now routinely possible to reprogram fully differentiated cells back to pluripotent cells, and to transdifferentiate cells of a given type in cells of a totally different lineage origin. However, whether there are key initiating factors that are distinct from those that control stem-cell renewal and that can initiate the reprogramming process remains unknown. In contrast, what is clear is that, by modifying the epigenetic status of a cell, its reprogramming can be initiated. Here, we review the current literature that shows how the plasticity of a cell can be modulated by modifying its epigenetic status, and we discuss how epigenetic barriers can be removed, to induce an efficient reprogramming process.     

Immigration of lymphoid precursor cells into the thymic rudiment inXenopus

Summary The origin of thymic lymphocytes was investigated, using a new reliable method to mark cells inXenopus. It was easily observed that extraneous cells immigrated into the thymic rudiment 4 days after fertilization and differentiated into a cell population identified as thymic lymphocytes in a fully developed thymus. Clearly, lymphoid precursor cells are of extrinsic origin.This work was supported in part by a grant from the Ministry of Education, Science and culture of Japan (No. 59770026).