The dental amalgam issue. A review

Using an interdisciplinary approach, the current position in the dental amalgam controversy and the potential impact of amalgam mercury on human health are reviewed. Aspects of materials science, corrosion, mercury exposure, toxicology, neurology and immunology are included. New data on mercury exposure from corroded amalgam fillings in vivo are presented. The exposure can reach levels considerably over known threshold limit values. Also, measurements of mercury absorption from intraoral air are presented. The vital importance of avoiding a galvanic amalgam-gold coupling is emphasized. The symptomatology of a disabled patient, who recovered after amalgam removal, has been included. It is concluded that discussion of the dental amalgam issue has suffered from the lack of an interdisciplinary approach. It would be wise to learn from the lesson of acrodynia, and consider amalgam mercury among other possible factors in neurological and immunological diseases of unclear etiology.     

Chronic mercury vapor poisoning of aphids

Summary Exposure of green peach aphids,Myzus persicae (Sulz.), to an atmosphere containing mercury vapor resulted in a curtailment ofembryogenesis and larviposition by adults, and in the development by larvae and adults of a cuticular darkening of their legs, head capsule, antennae, cornicles and cauda. Mortality of affected larvae resulted from molting difficulties, particularly by last-instar alatiform female and male larvae. Greenbugs,Schizaphis graminum (Rond.), and pea aphids,Acyrthosiphon pisum (Harr.), responded to mercury vapor exposure in similar ways.     

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.     

Out of the fog: Catalyzing integrative capacity in interdisciplinary research

Social studies of interdisciplinary science investigate how scientific collaborations approach complex challenges that require multiple disciplinary perspectives. In order for collaborators to meet these complex challenges, interdisciplinary collaborations must develop and maintain integrative capacity, understood as the ability to anticipate and weigh tradeoffs in the employment of different disciplinary approaches. Here we provide an account of how one group of interdisciplinary fog scientists intentionally catalyzed integrative capacity. Through conversation, collaborators negotiated their commitments regarding the ontology of fog systems and the methodologies appropriate to studying fog systems, thereby enhancing capabilities which we take to constitute integrative capacity. On the ontological front, collaborators negotiated their commitments by setting boundaries to and within the system, layering different subsystems, focusing on key intersections of these subsystems, and agreeing on goals that would direct further investigation. On the methodological front, collaborators sequenced various methods, anchored methods at different scales, validated one method with another, standardized the outputs of related methods, and coordinated methods to fit a common model. By observing the process and form of collaborator conversations, this case study demonstrates that social studies of science can bring into critical focus how interdisciplinary collaborators work toward an integrated conceptualization of study systems.     

La pression intrarénale chez l'homme

Summary The intrarenal pressure has been determined in man using a needle of the lumbal puncture type connected with a mercury manometer. Preliminary results in 8 patients with various renal diseases indicate no significant difference between cases of glomerulonephritis, acute anuria, chronic pyelonephritis and normal or almost normal kidneys. Our values are comprised between 23.5 and 41.5 mm of mercury, with an average of 34 mm. A possible correlation with the mean blood pressure is suggested by our data: intrarenal pressure =0.19 mean blood pressure +9.0. In one case, renal decapsulation had no influence on the intrarenal pressure.     

Forecasting non-normal time series

We look at the problem of forecasting time series which are not normally distributed. An overall approach is suggested which works both on simulated data and on real data sets. The idea is intuitively attractive and has the considerable advantage that it can readily be understood by non-specialists. Our approach is based on ARMA methodology and our models are estimated via a likelihood procedure which takes into account the non-normality of the data. We examine in some detail the circumstances in which taking explicit account of the nonnormality improves the forecasting process in a significant way. Results from several simulated and real series are included.     

Modelling gene regulation: (De)compositional and template-based strategies

Although the interdisciplinary nature of contemporary biological sciences has been addressed by philosophers, historians, and sociologists of science, the different ways in which engineering concepts and methods have been applied in biology have been somewhat neglected. We examine – using the mechanistic philosophy of science as an analytic springboard – the transfer of network methods from engineering to biology through the cases of two biology laboratories operating at the California Institute of Technology. The two laboratories study gene regulatory networks, but in remarkably different ways. The research strategy of the Davidson lab fits squarely into the traditional mechanist philosophy in its aim to decompose and reconstruct, in detail, gene regulatory networks of a chosen model organism. In contrast, the Elowitz lab constructs minimal models that do not attempt to represent any particular naturally evolved genetic circuits. Instead, it studies the principles of gene regulation through a template-based approach that is applicable to any kinds of networks, whether biological or not. We call for the mechanists to consider whether the latter approach can be accommodated by the mechanistic approach, and what kinds of modifications it would imply for the mechanistic paradigm of explanation, if it were to address modelling more generally.     

对跨学科大学高等研究院评价的几点思考

在梳理中国现有大学高等研究院的基础上,从学科类型、数量质量、评价对象、评价主体、评价方法、评价过程六个方面构建了大学高等研究院评价框架.然后结合我国高等研究院发展的特点,对如何做好大学高等研究院评价工作提出了一系列的建议.     

Le Dosage Spectrométrique du Mercure dans l'Air vers 1930

In the 1930s, atomic absorption spectroscopy replaced chemical methods for determining the amount of mercury in atmospheric air. The overall state of chemical analysis was favourable: physical instruments were moving into the chemical laboratory. This new method emerged from work in quantitative physics, and it met a need arising from the risk encountered by those who handled mercury. The new spectrometer, which originally functioned as a detector, also made precise and rapid quantitative determinations possible. This in turn encouraged industrialists to take out patents and make commercial use of the method after various improvements. This method is considered to be the ancestor of modern atomic absorption spectroscopy, which developed independently after 1960. The method developed in the 1930s could only be used for gaseous mercury, and it was not generalized as a method for quantifying other elements. The determination of mercury in air by atomic absorption spectroscopy was the first application of this technique; indeed, it was the only example of a specific use of atomic absorption. It was also part of the instrumental revolution.     

Study on the distribution of methyl-mercury (203Hg) by whole body autoradiography of macaque monkeys (Macaca irus)]

The distribution of methyl-mercury labelled with mercury-203 has been studied in Monkeys by whole body autoradiography technique. The mercury is rapidly absorbed. It is localized in all the body and mainly in well defined areas of the central nervous system.     

The epidemiology of dental caries in relation to environmental trace elements

Summary This paper reviews the influence of the geochemical environment on the epidemiology of human dental caries. The best documented association is that between water borne fluoride and reduced caries prevalence. The influence of fluoride was first reported during the early decades of this century in Colorado, USA, and led to the fluoridation of some public water supplies in several countries. In all cases, fluoridation has been followed by significant improvements in dental health and no adverse effects in general health. Other trace elements in food and water have now been linked with dental caries. Molybdenum has been associated with reduced caries prevalence whereas selenium and lead appear to have adverse effects. Cavity formation in teeth probably involves a localised dissolution of the enamel surface by the products of bacterial activity. It is possible that the incorporation of trace metals into the apatite microcrystals of enamel may alter their physical properties, especially solubility, and hence their susceptibility to degradation.     

Experiments with interactional expertise

‘Interactional expertise’ is developed through linguistic interaction without full scale practical immersion in a culture. Interactional expertise is the medium of communication in peer review in science, in review committees, and in interdisciplinary projects. It is also the medium of specialist journalists and of interpretative methods in the social sciences. We describe imitation game experiments designed to make concrete the idea of interactional expertise. The experiments show that the linguistic performance of those well socialized in the language of a specialist group is indistinguishable from those with full blown practical socialization but distinguishable from those who are not well socialized. The imitation game can also be used to indicate whether an individual can enter an esoteric domain and master the interactional expertise, a skill required by interpretative sociologists of science, anthropologists, ethnographers, and the like.     

The epidemiology of dental caries in relation to environmental trace elements

This paper reviews the influence of the geochemical environment on the epidemiology of human dental caries. The best documented association is that between water borne fluoride and reduced caries prevalence. The influence of fluoride was first reported during the early decades of this century in Colorado, USA, and led to the fluoridation of some public water supplies in several countries. In all cases, fluoridation has been followed by significant improvements in dental health and no adverse effects in general health. Other trace elements in food and water have now been linked with dental caries. Molybdenum has been associated with reduced caries prevalence whereas selenium and lead appear to have adverse effects. Cavity formation in teeth probably involves a localised dissolution of the enamel surface by the products of bacterial activity. It is possible that the incorporation of trace metals into the apatite microcrystals of enamel may alter their physical properties, especially solubility, and hence their susceptibility to degradation.     

The effect of five proteins on stem cells used for osteoblast differentiation and proliferation: a current review of the literature

Bone-tissue engineering is a therapeutic target in the field of dental implant and orthopedic surgery. It is therefore essential to find a microenvironment that enhances the growth and differentiation of osteoblasts both from mesenchymal stem cells (MSCs) and those derived from dental pulp. The aim of this review is to determine the relationship among the proteins fibronectin (FN), osteopontin (OPN), tenascin (TN), bone sialoprotein (BSP), and bone morphogenetic protein (BMP2) and their ability to coat different types of biomaterials and surfaces to enhance osteoblast differentiation. Pre-treatment of biomaterials with FN during the initial phase of osteogenic differentiation on all types of surfaces, including slotted titanium and polymers, provides an ideal microenvironment that enhances adhesion, morphology, and proliferation of pluripotent and multipotent cells. Likewise, in the second stage of differentiation, surface coating with BMP2 decreases the diameter and the pore size of the scaffold, causing better adhesion and reduced proliferation of BMP-MSCs. Coating oligomerization surfaces with OPN and BSP promotes cell adhesion, but it is clear that the polymeric coating material BSP alone is insufficient to induce priming of MSCs and functional osteoblastic differentiation in vivo. Finally, TN is involved in mineralization and can accelerate new bone formation in a multicellular environment but has no effect on the initial stage of osteogenesis.     

Methylmercury toxicity in insect: detection of mercury in lysosomes using electron microprobe]

Intoxication of Blattella by methylmercury leads to a storage of the ingested metal within the lysosomes of ileum. Mercury is always found associated with zinc, sulphur and copper. Lysosome, therefore, intervenes in a detoxication process in Insects which have been exposed to organic mercury. It is suggested that mercury might be trapped by metallothionein.     

Making more synapses: a way to store information?

Although information may be stored in the brain as changes in the strength of existing synapses, formation of new synapses has long been thought of as an additional substrate for memory storage. The identification of subcellular structural changes following learning in mammals poses a serious ‘needle-in-the-haystack’ problem. In most attempts to demonstrate structural plasticity during learning, animals have been exposed for prolonged periods to complex environments, where they are confronted with a variety of sensory, motor and spatial challenges throughout the exposure period. These environments are thought to promote several forms of learning. Repeated exposure to such environments has been shown to increase the density of spines and dendritic complexity in relevant brain structures. The number of neurons has also been reported to increase in some areas. It is not clear, however, whether the new synapses emerging from these forms of plasticity mediate specific information storage, or whether they reflect a more general sophistication of the excited parts of the network.     

Steigerung der Genauigkeit bei astronomischen Durchgangsbeobachtungen

Summary The influence of the axis-inclination on the transit time can be eliminated by the observation of the star image reflected by a mercury level together with the influence of the variable collimation produced by a flexion of the axis.The hand-driving of the impersonal micrometer has been remplaced by a motor with an additional wheelwork permitting to move the micrometer independently from the motor mechanism. Both improvements increase the precision of the transit observations.     

水环境中痕量、超痕量元素汞的形态分析技术进展

水环境中汞的含量虽微,但其毒性甚大。水环境中汞的赋存形态不同,其毒性亦不同,汞总量的测定已不能充分揭示汞的毒性及其生物有效性。本文较为详尽的归纳总结了近年来水环境中汞形态分析的样品处理技术及其形态分析技术进展。     

Molecular and engineering approaches to regenerate and repair teeth in mammals

Continuous replacement of teeth throughout the lifespan of an individual is possibly basal for most of the vertebrates including fish and reptiles; however, mammals generally have a limited capacity of tooth renewal. The ability to induce cellular differentiation in adults to replace lost or damaged cells in mammals, or to tissue-engineer organs in vitro, has hence become one of the major goals of regenerative medicine. In this article, we will revisit some of the important signals and tissue interactions that regulate mammalian tooth development, and will offer a synopsis of the latest progress in tooth regeneration and repair via molecular and engineering approaches. It is hoped that this article will not only offer an overview of recent technologies in tooth regeneration and repair but will also stimulate more interdisciplinary research in this field to turn the pursuit of tooth regeneration and repair into practical reality.     

Collaboration,interdisciplinarity, and the epistemology of contemporary science

Over the last decades, science has grown increasingly collaborative and interdisciplinary and has come to depart in important ways from the classical analyses of the development of science that were developed by historically inclined philosophers of science half a century ago. In this paper, I shall provide a new account of the structure and development of contemporary science based on analyses of, first, cognitive resources and their relations to domains, and second of the distribution of cognitive resources among collaborators and the epistemic dependence that this distribution implies. On this background I shall describe different ideal types of research activities and analyze how they differ. Finally, analyzing values that drive science towards different kinds of research activities, I shall sketch the main mechanisms underlying the perceived tension between disciplines and interdisciplinarity and argue for a redefinition of accountability and quality control for interdisciplinary and collaborative science.