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Functional magnetic materials are used in a wide range of "green" applications, from wind turbines to magnetic refrigeration. Often the magnetic materials used contain expensive and/or scarce elements, making them unsuitable for long term solutions. Further, traditional material discovery is a slow and costly process, which can take over 10 years. Material informatics is a growing field, which combines informatics, machine learning (ML) and high-throughput experiments to rapidly discover new materials. To prove this concept, we have devised a material informatics workflow and demonstrated the core components of natural language processing (NLP) to extract data from research papers to create a functional magnetic material database, machine learning with semi-heuristic models to predict compositions of soft magnetic materials, and high-throughput experimental evaluation using combinatorial sputtering and high-throughput magneto-optic Kerr effect (MOKE) magnetometry. This material informatics workflow provides a quicker, cheaper route to functional magnetic materials discovery. [ABSTRACT FROM AUTHOR]

Cost-effective and controllable synthesis of M0.25Ni0.15Cu0.25Co0.35Fe2O4 (M2+ = Mg2+, Mn2+, and Cd2+) ferrites via the sol–gel auto-combustion technique. The impact of divalent cations on the structural, dielectric, and optoelectrical properties of ferrites was examined by XRD, FTIR, Raman, LCR, UV–Vis, and two probe I-V measurement techniques. The crystallite size was 52.66 nm, and the minimum specific surface area was observed 5.1507 m2/g for Mg2+ doped NCCF ferrite. The FTIR and Raman analysis also confirmed the substitution of divalent cations (M2+ = Mg2+, Mn2+, and Cd2+) at their respective lattice sites. The maximum energy bandgap was 1.67 eV Mg2+-doped NCCF ferrite as compared to other divalent ion-doped ferrites. The dielectric loss decreased while the ac conductivity increased with increasing frequency, and the minimum values were observed for Mg2+-doped NCCF ferrite. The activation energy was observed maximum for Mg2+-doped NCCF ferrite (0.2234 eV). Due to incredible properties including small specific surface area, large energy band gap, high resistivity, and loss dielectric loss of Mg2+-doped NCCF ferrite have potential applications in different fields. [ABSTRACT FROM AUTHOR]

Cadmium ferrites belong to normal spinel ferrites, and they exhibit interesting electrical, magnetic, and optical properties. The pure and cerium-doped cadmium ferrites CdFe2−xCexO4 (x = 0.0, 0.125, 0.250, 0.375, 0.5) were synthesized by a chemical co-precipitating technique using sodium hydroxide as a co-precipitating agent. The structures and phase purity of fabricated nanomaterials were analyzed by X-ray diffraction (XRD). The crystallite size for all the prepared nanomaterials was in the range of 28–46 nm. The lattice constant and unit cell volume were found to decrease with the increasing concentration of Cerium, which was confirmed by the peak shift in the XRD pattern. The X-ray density for all nano ferrites increased with the enhancement of cerium composition. The resistivity of the nanomaterials has random behavior with the enhancement of cerium composition for a temperature, but the value of resistivity at x = 0.125 has the lowest value and at x = 0.375 has the highest value for almost all temperatures. For specific concentrations, a decreasing trend of resistivity of fabricated materials was found with an increment of temperature. The activation energies were also calculated, and it increased for x = 0.125 and then decreased for all the nanomaterials. For the confirmation of the M–O bonds, FTIR analysis of all the nano ferrites was also performed. The analysis shows a higher frequency absorption band in the range of 531.24–534.84 cm−1. This absorption band confirms that metal oxides are formed in all the synthesized nanoparticles. [ABSTRACT FROM AUTHOR]

The high interest in FeGa films is due to the high magnetostriction present in single crystal thin films. There is, however, significant reduction in the magnetostriction when grown using sputtering. The reduction is explained here using finite element analysis by considering the local magnetocrystalline and magnetoelastic behavior of the grains within the sample. It is shown that, if the saturation magnetostrictive constant for each grain in a polycrystalline structure is of the order of 400 ppm, this is reduced to less than 90 ppm when the crystallites are randomly orientated. Furthermore, the inherent stress due to the sample fabrication leads to an increase in the anisotropy field. This work suggests that, with low stress fabrication and aligning the in-plane orientation of the crystallites, the potential in unlocking FeGa as a thin film for sensory applications can be realised. [ABSTRACT FROM AUTHOR]

In Britain, a tradition of scientists actively communicating new developments in their fields with the general public has existed since the Victorian era. During the early twentieth century there were major developments in the nature of scientific communication with the rise of the mass media represented by popular magazines, newspapers and books, alongside the creation of a national radio broadcasting network. Many professional scientists took advantage of these changes to develop non-specialist careers through writing articles, books or radio talks for the enlightenment of the general public or the education of school children. However, most of this bibliographical material is ephemeral and may be ignored when considering the careers of the most distinguished scientists. One such scientist whose non-specialist activities have been generally undervalued is Munro Fox FRS (1889–1967). He was an eminent zoologist who, alongside a successful research career, had a well-developed non-specialist output promoting biological subjects that included many magazine articles and books as well as a substantial number of radio talks, particularly within the British Broadcasting Corporation's (BBC) Broadcasts to Schools programme. [ABSTRACT FROM AUTHOR]

This work focuses on the effect of film thickness on the microstructural and magnetic properties of polycrystalline Fe80Ga20 films of different thickness (20 nm⩽t⩽200 nm) fabricated on Si(100) substrates. From x-ray diffraction, a <110> texture was normal to the film plane in all films. For all film thicknesses, the lattice constant perpendicular to the film plane was less than the bulk, and first decreased and then increased toward the bulk value with increasing t. From atomic force microscopy data, both surface roughness and grain size were found to increase with film thickness. Using the Villari effect, the effective magnetostriction constant λeff was measured. Using the Szymczak model, it was found that λbulk=91±5 ppm, close to the bulk isotropic polycrystalline value (λiso=98 ppm). The surface magnetostriction λs contribution to λeff was found to be -1065±271 ppm nm. It was found that the 20 nm thick film had weak uniaxial anisotropy, while all the other films were magnetically isotropic. An extension of Néel's model to saturation field showed that the experimental data obeyed this model and the surface term affected the effective saturation field (Hs eff) significantly. [ABSTRACT FROM AUTHOR]

Results from studies of spin dependent transport in the hole transporting organic semiconductor regioregular poly 3-hexylthiophene (RR-P3HT) are reported. The organic spin valves were grown on glass, with the structure Fe50Co50/RR-P3HT/Ni81Fe19. RR-P3HT was cast from five different solvents with different boiling points; 1,2,4 trichlorobenzene, toluene, xylene, chloroform, and chlorobenzene. Magnetoresistance measurements were carried out at room temperature. Spin dependent transport was only observed when toluene, xylene, and annealed 1,2,4 trichlorobenzene were used as solvents. Results are interpreted on the basis of differences in the RR-P3HT morphology induced by different solvents under fixed processing conditions. [ABSTRACT FROM AUTHOR]

The structural, magnetic, and magnetostrictive properties of 75 nm Fe100-xGax films (0≤x≤30) have been studied to determine how a forming field during growth affects these properties. Two film sets were grown using a cosputtering-evaporation technique with and without a forming field of 65 kA m-1. Using x-ray diffraction, the texture, lattice parameter, and the grain size were determined. An out-of-plane <110> texture was found for all films. The magnetization loops were measured on a magneto-optic Kerr effect magnetometer, from which the anisotropy symmetry was inferred from the remanent magnetization. It was found that the forming field produced a pronounced uniaxial anisotropy. The effective magnetostriction constant was measured using the Villari effect. The effective magnetostriction constant was compared with that calculated for a polycrystalline film with <110> out-of-plane texture using bulk constants, and the results are discussed. [ABSTRACT FROM AUTHOR]

The magnetoresistance (MR) of organic spin valves containing the spacer layer regioregular poly(3-hexylthiophene) (RR-P3HT), which is a conjugated polymer, has been studied at room temperature. Investigations have been made of the influence of the thickness of organic spacer layer on the magnetoresistance of Fe50Co50/RR-P3HT/Ni81Fe19 spin valves. It was determined that the MR decreased as the layer thickness increased, consistent with the spin coherence length in this material. It has been observed at room temperature that there is the co-occurrence of two magnetoresistance effects, the spin-valve magnetoresistance, and anisotropic magnetoresistance in the magnetic electrodes. [ABSTRACT FROM AUTHOR]

Thin epitaxial Fe films grown on GaAs(100) and Ga0.8In0.2As(100) substrates were investigated to determine how tuning the lattice constant mismatch between the Fe and the substrate may change the in-plane anisotropies and the magnetostriction. Two sets of Fe films were grown using molecular-beam epitaxy, each capped with a Cr overlayer. For each film, the in-plane anisotropy constants were determined from the normalized magnetization loops measured using a magneto-optic Kerr effect magnetometer. The lattice mismatch was found to give no contribution to the in-plane anisotropies. For all the films the magnetostriction constants, determined by the Villari method, were negative and became more negative as the Fe thickness decreased. [ABSTRACT FROM AUTHOR]

In this article we present data which show that Cr overlayers on epitaxial Fe films on GaAs substrates change the magnetic properties of the films in comparison to Au overlayers. For films thinner than 50 ML, the presence of the Cr overlayer reduced the magnitude of the uniaxial anisotropy in the Fe film, while for a 150 ML film, there was still a strong uniaxial anisotropy present. The anisotropy constants were determined using a modified energy density model, and were found to be smaller than those for Au overlayer films. The absolute magnetizations were measured on a vibrating sample magnetometer. It was determined that for the same thickness of Fe the magnetization with a Cr overlayer was 75% of that for a Au overlayer. This was either due to the Cr alloying with the Fe at the interface, or the Cr forming CrO2 on the surface of the film. The magnetostriction constant was determined using the Villari effect. For all the films the saturation magnetostriction constant was more negative than the bulk Fe value. [ABSTRACT FROM AUTHOR]

We report an experimental and theoretical study of the influence of uniaxial strain on the magnetic properties of Fe/GaAs(100) ultrathin film systems. In-plane tensile strains have been applied along different directions relative to the intrinsic uniaxial magnetic anisotropy axes of the Fe/GaAs(100) films, and the M-H loops were measured. In an attempt to interpret the observed behavior, a phenomenological energy model is considered, which incorporates both intrinsic and strain-induced uniaxial anisotropy terms. Theoretical magnetization reversal loops were obtained from the model, assuming that the magnetoelastic coefficients of the thin films are same as the bulk bcc Fe. The model qualitatively predicted the magnetization loops for all the experimental data, assuming a positive uniaxial anisotropy constant. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Richard Owen (1804-1892) is one of the most important British biologists of the nineteenth century, making significant contributions in the field of comparative anatomy. However, one aspect of his scientific output continues to be overlooked, namely his contributions to parasitology and the influence parasites had on formulating his ideas on comparative anatomy and sexual reproduction. An overview of Owen's writings on parasites is presented delineated into three phases, a primary research phase during the 1830s including descriptions of the important human parasite Trichinella spiralis, a secondary phase of using parasites as models for his biological theories during the 1840s and 1850s, and a latter phase dominated by the controversy surrounding priority for the discovery of T. spiralis. Owen is considered as a pioneer of parasitology research whose popularization of the field provided a receptive environment in the UK that facilitates the ground breaking research in tropical parasitology undertaken by other researchers during the late nineteenth century. A bibliography of Owen's publications on parasites is included as an appendix. [ABSTRACT FROM AUTHOR]

We overview current experiments and accompanying theoretical studies in the area of MHD thermofluids in the US, which are aimed at characterization of MHD flows coupled with heat and mass transfer in fusion breeding blankets. We also outline recent upgrades of the experimental MHD facility at UCLA called MaPLE (Magnetohydrodynamic PbLi Experiment) and introduce near-future experimental plans. [ABSTRACT FROM AUTHOR]

Remote sensing and inverse modelling studies indicate that the tropics emit more CH4 and N2O than predicted by bottom-up emissions inventories, suggesting that terrestrial sources are stronger or more numerous than previously thought. Tropical uplands are a potentially large and important source of CH4 and N2O often overlooked by past empirical and modelling studies. To address this knowledge gap, we investigated spatial, temporal and environmental trends in CH4 and N2O fluxes across a long elevation gradient (600-3700ma.s.l.) in the Kosñipata Valley, in the southern Peruvian Andes that experiences seasonal fluctuations in rainfall. The aim of this work was to produce preliminary estimates of CH4 and N2O fluxes from representative habitats within this region, and to identify the proximate controls on soil CH4 and N2O dynamics. Ecosystems across this altitudinal gradient were both atmospheric sources and sinks of CH4 on an annual basis. Montane grasslands (or, puna; 3200-3700ma.s.l.) were strong atmospheric sources, emitting 56.94±7.81 kgCH4 -Cha-1 yr-1. Upper montane forest (2200-3200ma.s.l.) and lower montane forest (1200-2200ma.s.l.) were net atmospheric sinks (-2.99±0.29 kgCH4-Cha-1 yr-1 and -2.34±0.29 kgCH4-Cha-1 yr-1, respectively); while premontane forests (600-1200ma.s.l.) fluctuated between source or sink depending on the season (wet season: 1.86±1.50 kgCH4-Cha-1 yr-1; dry season: -1.17±0.40 kgCH4-Cha-1 yr-1). Analysis of spatial, temporal and environmental trends in CH4 flux across the study site suggest that soil redox was a dominant control on net CH4 flux. CH4 emissions were greatest from elevations, landforms and during times of year when soils were sub-oxic, and CH4 efflux was inversely correlated with soil O2 concentration (r² = 0.82, F1,125 = 588.41, P < 0.0001). Ecosystems across the region were net atmospheric N2O sources. N2O fluxes declined with increasing elevation; N2O emissions from premontane forest, lower montane forest, upper montane forest and montane grasslands averaged 2.23±1.31 kgN2O-Nha-1 yr-1, 1.68±0.44 kgN2O- Nha-1 yr-1, 0.44±0.47 kgN2O-Nha-1 yr-1 and 0.15±1.10 kgN2O-Nha-1 yr-1, respectively. N2O fluxes from premontane and lower montane forests exceeded prior model predictions for the region. Comprehensive investigation of field and laboratory data collected in this study suggest that N2O fluxes from this region were primarily driven by denitrification; that nitrate (NO3-) availability was the principal constraint on N2O fluxes; and that soil moisture and water-filled porosity played a secondary role in modulating N2O emissions. Any current and future changes in N management or anthropogenic N deposition may cause shifts in net N2O fluxes from these tropical montane ecosystems, further enhancing this emission source. [ABSTRACT FROM AUTHOR]

Zooplanktonic animals live in the open water of freshwater habitats, whilst trematodes are ubiquitous parasitic worms of aquatic vertebrates and invertebrates. A defining characteristic of trematode life cycles is the cercariae, a mainly planktonic free-living larval stage that emerges into the aquatic environment from infected molluscan hosts. Cercariae are lecithotrophic (non-feeding) larvae analogous of meroplankton. Although millions of planktonic cercariae enter freshwater habitats on a daily basis and are capable of forming into dense clouds, they are a largely neglected component of the zooplankton community, rarely mentioned in faunal studies. Nevertheless, there is increasing evidence to suggest that cercariae have important secondary roles in aquatic food webs and energy transfer. This article reacquaints freshwater biologists with cercariae, highlighting the key characteristics of their biology and population dynamics, their role in food webs, public health and veterinary importance, and the risk of increased population densities under the influence of climate change. The reasons for their neglect in freshwater biology is evaluated and considered to be associated with zooplankton sampling methodologies being unsuitable for collecting cercariae and the paucity of identification keys in the limnological literature. [ABSTRACT FROM AUTHOR]

Spintronics has shown a remarkable and rapid development, for example from the initial discovery of giant magnetoresistance in spin valves to their ubiquity in hard-disk read heads in a relatively short time. However, the ability to fully harness electron spin as another degree of freedom in semiconductor devices has been slower to take off. One future avenue that may expand the spintronic technology base is to take advantage of the flexibility intrinsic to organic semiconductors (OSCs), where it is possible to engineer and control their electronic properties and tailor them to obtain new device concepts. Here we show that we can control the spin polarization of extracted charge carriers from an OSC by the inclusion of a thin interfacial layer of polar material. The electric dipole moment brought about by this layer shifts the OSC highest occupied molecular orbital with respect to the Fermi energy of the ferromagnetic contact. This approach allows us full control of the spin band appropriate for charge-carrier extraction, opening up new spintronic device concepts for future exploitation. [ABSTRACT FROM AUTHOR]

Parasitism of fish in fully bunded storage reservoirs has rarely been studied, while the impact of a rapid decline in a fish population on its parasite fauna is poorly understood. The present paper investigates the helminth fauna of perch (Perca fluviatilis) over a 5-year period in the Queen Mary reservoir, a large (290 ha) completely artificial water storage impoundment, which forms a unique and challenging habitat for its resident fish population. After 3 years of study, the perch population suffered a significant reduction due to a disease outbreak caused by the pathogenic bacterium Flavobacterium column are, 'columnaris disease', and the subsequent effects on the helminth fauna over the next 2 years are evaluated. Conditions in the reservoir favour the development of large populations of zooplankton, which act as intermediate hosts for the majority of helminths in the dominant perch community. The prevalence and intensity of helminth infections showed much variation over the period prior to the perch mortality. These were likely to be due to changes in the zooplankton biomass, which was exposed to biotoxins released from periodic algal blooms and the application of copper to control them. The outbreak of F. column are resulted in a significant decrease in the size and condition coefficient of the perch population. Changes also occurred in the composition of helminth parasites, with many species demonstrating either an increase or decrease in infection levels. These changes may be partly associated with an increase in the zooplankton biomass and altered population structure, probably caused by a decrease in fish predation pressure, which would influence the parasite population dynamics, although other factors directly associated with changes in the perch population are also likely to be influential. The long-term affects on the levels of helminth infections in the fish and associated intermediate hosts in the Queen Mary reservoir are discussed. [ABSTRACT FROM AUTHOR]

In fish there is a close association between endocrine and immune function that during seasonal changes in reproductive status can affect the fishes susceptibility to parasitic infection. The effects of endocrine-disrupting pollution on this association are not known. The present study investigates the effects of a chemically polluted (ammoniacal nitrogen, zinc, bromide) discharge in Cranleigh Waters, a river in southern England, on the fecundity and parasitism of chub, Leuciscus cephalus, over an 18-month period. In the polluted site, the gonado-somatic index (GSI) of fish was lower in females and higher in males compared to an unpolluted upstream site, indicating an androgenic effect on reproduction. Parasite species richness, especially the intestinal helminths Proteocephalus torulosus and Pomphorynchus laevis, was increased in fish in the polluted site. However, the occurrence of the two most common parasite species in the river— Myxobulus sp. 1, a gill myxozoan, and Diplostomum sp., a trematode found in the eye—was unchanged between polluted and unpolluted river sites. Nevertheless, there was a significant relationship between GSI and the prevalence of these two parasite species in the unpolluted site but not the polluted site suggesting that endocrine disruption of reproduction did not lead to an increase in host susceptibility. The reasons for this are discussed. [ABSTRACT FROM AUTHOR]

Electronic devices that use the spin degree of freedom hold unique prospects for future technology. The performance of these ‘spintronic’ devices relies heavily on the efficient transfer of spin polarization across different layers and interfaces. This complex transfer process depends on individual material properties and also, most importantly, on the structural and electronic properties of the interfaces between the different materials and defects that are common to real devices. Knowledge of these factors is especially important for the relatively new field of organic spintronics, where there is a severe lack of suitable experimental techniques that can yield depth-resolved information about the spin polarization of charge carriers within buried layers of real devices. Here, we present a new depth-resolved technique for measuring the spin polarization of current-injected electrons in an organic spin valve and find the temperature dependence of the measured spin diffusion length is correlated with the device magnetoresistance. [ABSTRACT FROM AUTHOR]

We have compared the magnetoresistance of organic spin-valve (SV) structures with regioregular and regiorandom poly (3-hexylthiophene) (RR-P3HT and RRa-P3HT), hole transporting polymers, as the spacer layers sandwiched between two ferromagnetic electrodes. A SV structure of Fe[sub50]Co[sub50]/RRa-P3HT/Ni[sub81] Fe[sub19] was the test structure used. At room temperature, we observed the co-occurrence of two magnetoresistance effects, the spin magnetoresistance and magnetoresistance in the electrodes. [ABSTRACT FROM AUTHOR]

A new deposition technique involving the dc magnetron sputtering of Fe simultaneously with Ga evaporation has been developed to fabricate thin Fe(1-x)Gax (0

An adaptation of the Comet-assay was developed which enables the discrimination of viable, apoptotic and necrotic single cells by use of the common Annexin-V staining and a dye exclusion test on the cells already embedded in agarose gel on glass slides. Membrane integrity (Ethidium–Homodimer exclusion), cellular esterase activity (Calcein blue-AM) as well as translocation of phosphadidyl-serine (Annexin-V) were analysed using these stains. The advantage of the ‘apo/necro-Comet-assay’ is that the viability status of individual cells can be determined and correlated with the DNA fragmentation pattern (comet) formed by the same cells. Hence, DNA damage can be assessed and correlated with viable cells or cells undergoing early, mid- or late stage apoptosis or necrosis as identified by the staining pattern. The staining was verified using heat and etoposide-induced apoptosis. This technique, among others, was used to study whether apoptotic fragmentation interferes with repair kinetics measured with the comet assay following UVA exposure (doses up to 1280 kJ/m2) in the cultured human keratinocytes (HaCaT). Therefore, a time course of apoptotic events (phosphatidyl translocation and TUNEL fragmentation) was established and correlated to the DNA fragmentation in the comet-assay. Apoptotic cells were detected more than 8 h later. The combined three-colour staining method with the comet assay showed that there was no significant interference of DNA repair by apoptotic fragmentation processes since DNA repair was almost completed before the onset of apoptotic fragmentation. The apo/necro-Comet-assay reduces the general problem of false-positive results in genotoxicity tests using the Comet-assay. [ABSTRACT FROM AUTHOR]

Tungsten (W) has one of the highest melting points (3410±20°C) among the elements in the periodic table and therefore has gained considerable attention for high temperature applications such as porous tungsten as a high current density cathode for flash lamps or electronic valves. Its brittle behaviour and high density have also been important factors in the processing methods employed. Through the years it has been processed mostly using PM techniques in order to obtain different forms. To obtain densification, it is necessary to apply high temperatures during sintering. This paper considers a novel approach to the pressing and sintering of tungsten powders and how their densification can be improved. One potential aid is to add very small amount of Al as a binder. The densification characteristics are presented using SEM analysis to develop the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Porous tungsten as a high current density cathode is one of the important applications of the metal, which is mostly used in high temperature conditions due to its exceptional resistance to melting (Tm = 3410±20°C). Its porous form has been a crucial component of dispenser cathodes used in electronic valves and high power lamps. Porous tungsten skeleton forms the matrix, which is then impregnated with an electron emissive compound. Upon every emission from the surface, new material has to be fed into the surface pores via the open pore channels. Hence it may be proposed that a uniform porosity is needed for a better performance. However, a controlled porosity has not been achieved yet. Moreover, sintering of tungsten has always been difficult due to the extreme process conditions. A high sintering temperature (Ts≥2000°C) and a strong reductive atmosphere (hydrogen) have been the absolute necessity in making these parts. This study further explores an alternative sintering technique being developed. The idea is based on the reactive sintering concept. The energy output from the exothermic reactive system of tungsten oxide and aluminium has been the heat source for sintering porous tungsten. As a result, sintering temperature and time have been reduced considerably. Higher homogeneity, thus more uniform pore distribution, was observed. A better control of porosity related to the pressing and sintering conditions was achieved by the characterisation method previously developed. Microhardness has been a useful monitor of the scatter in porosity of the parts. Throughout the study, SEM was used to observe the porous structures and powder morphologies. DSC and XRD were useful to follow the microstructural evolution in the reactive system. [ABSTRACT FROM AUTHOR]

It has been shown recently that porous tungsten can be obtained at much lower temperatures T ≤ 1200°C than those in conventional techniques where T ≥ 2000°C. This has been achieved by employing the concept of reactive sintering. The method makes use of the addition of Al, a low melting point phase which decreases the process temperature while acting as a potential sintering aid. As a result, higher homogeneity and uniform porosity distribution have been obtained. In this study, attention has been paid to the swelling phenomenon observed in porous tungsten upon post-sintering heat treatment. It has already been shown that swelling occurred in sintering porous tungsten by this alternative technique, and upon further heat treatment swelling instead of shrinkage became even more pronounced. This article explores the microstructural evolution upon post-sintering heat treatment on these parts. The relation between swelling and porosity for different tungsten particle sizes has been demonstrated. An attempt has been made to explain the possible reasons behind the changes in the porous structure. SEM has been a useful tool for the purpose of this study. [ABSTRACT FROM AUTHOR]

One of the most important applications of tungsten is its use as a high current density cathode in the form of porous tungsten impregnated with electron emissive salts. Powder metallurgy is the usual processing route to make these parts since melting and casting of tungsten is very tedious due to its high melting point (3410±20°C). The overall porosity and porosity distribution are crucial parameters for the performance and lifetime of porous tungsten cathodes. Although there is an active debate over what constitutes the optimal porosity distribution, lack of homogeneity is observed in conventional parts. This may contribute to a shorter cathode and hence lamp lifetime. These parts are conventionally sintered at temperatures in excess of 200°C. Furthermore, due to the high temperatures involved, the conventional sintering is very costly and energy consuming. This paper briefly looks into an alternative sintering process being developed for porous tungsten technology and its outcomes in terms of porosity distribution across the parts. As a result, the sintering temperature is dropped down to 1150°C and more homogeneous porous structures have been obtained. A characterisation method previously developed by the authors based on microhardness measurements is proved to be a good measure of the homogeneity of porous tungsten parts. [ABSTRACT FROM AUTHOR]

This article focuses on concentrations of metallothionein in heavy metals. Metallothioneins (MTs) are a group of low molecular weight, soluble, cysteine- rich and heat-stable proteins, which are induced by a variety of trace metals. Many fish and aquatic invertebrate species possess proteins that have features consistent with MTs, but often these metal-binding proteins are better referred to as metallothionein-like proteins (MTLPs) when they have not been purified and characterized to a sufficiently high level.

Porous tungsten is employed extensively for components such as dispenser cathodes in electronic valves and light technology. Normally parts are produced by die pressing or cipping and sintered in a reducing atmosphere at temperatures • 2000°C. In this study, the aim was to look critically at the behaviour of tungsten powder at compaction and sintering so that the distribution of porosity could be better controlled and optimised. Attention was focused on the basic powder properties, such as particle size and shape, surface area and apparent density. The effects of these parameters on the relative density of the parts are described. A small quantity of aluminium was added to the tungsten powder to serve as a binder and a potential sintering aid. [ABSTRACT FROM AUTHOR]

Abstract Increasing biological interest in minerals has led to the search for reliable methods to quantify body levels of trace elements and toxic metals. Hair has been a prime candidate because of its ease of collection and the possibility that this body tissue might accurately reflect body loads of these substances. A vast amount of research effort has been expended to explore the value of hair-element analysis. Unfortunately, there are so many confounding factors that influence these measurements that isolated individual results cannot be relied upon. Their current value is in epidemiological studies. [ABSTRACT FROM AUTHOR]

The toxicity of cadmium and zinc mixtures at concentrations ranging from 0.1 to 10,000 μg/L was investigated against the survival of the free-living cercarial stage of the parasitic fluke Diplostomum spathaceum. Cercariae were exposed to metal mixtures of equal concentration, metal mixtures of unequal concentration, and low-dose pretreatment followed by high-dose exposure mixtures. Under all exposures cercarial survival was increased compared to that achieved with single metals. At exposures with metal mixture of equal concentration in the range 0.1–100 μg/L survival was increased compared to that achieved by controls. The mechanism of metal toxicity and their effects on cercarial survival are discussed. [ABSTRACT FROM AUTHOR]

Single-cell gel electrophoresis (the comet assay) was used to assess single-strand breaks (SSBs) produced in cultured lung human fibroblasts by xenon lamp irradiation alone, various concentrations of arsenate [As(V)], alone or various combinations of the two. It was found that significantly higher levels of SSBs were observed in the irradiated cells than the nonirradiated cells and that elevating levels of arsenate enhanced the level of damage detected in both irradiated and nonirradiated cells in a concentration-dependent manner; that is, incubating cells with arsenate alone produced marked DNA damage without an irradiation insult being necessary. The results of this study indicate that arsenate is acting as a cogenotoxin with irradiation in this cell line. This additive effect may also be cocarcinogenic, and as a result it is possible that less solar irradiation may be required to induce skin cancer in arsenic-exposed populations. [ABSTRACT FROM AUTHOR]

Liquid wall concept has a significant place in the Advanced Power Extraction (APEX) study as a part of the US program on Nuclear Fusion. In the present paper, different approaches currently developed for modeling liquid wall magnetohydrodynamics and heat transfer in APEX have been presented. Turbulent flows of low-conductivity liquids, such as molten salts (Flibe), are analyzed using a two-equation turbulence model and Direct Numerical Simulation. The analysis of liquid metal flows under a strong reactor magnetic field is based on the magnetohydrodynamic equations for laminar flows. [ABSTRACT FROM AUTHOR]

The stereochemical course of the hydrolysis of synthetic sn-glycerol-1-palmitate-2-oleate-3-linoleate, sn-glycerol-1,2-dipalmitate-3-oleate and their antipodes by pancreatic and milk lipoprotein lipase was investigated by thin layer and gas liquid chromatographies of the diacylglycerol intermediates. The enzymic hydrolyses were made with bile salts or lysolecithin in a 1∶1 molar ratio to the substrate as emulsifiers and were limited to short time intervals which minimized isomerization and the reversal of lipolysis. In all instances, the products of hydrolysis by lipoprotein lipase contained a marked preponderance of the 2,3-diacylglycerols, while the composition of the diacylglycerol intermediates in the products of pancreatic lipase varied with the nature of the fatty acid in the 1 and 3 positions of the triacylglycerol molecule. Pancreatic lipase, but not lipoprotein lipase, gave a preferential release of unsaturated fatty acids. The above results are similar to those obtained with radioactive trioleoylglycerol and conventional stereospecific analyses and suggest that lipoprotein lipase may favor attack on the sn-1 position. It is hypothesized that the small amounts of the 1,2-diacylglycerols present may have arisen from a reversal of lipolysis also catalyzed by this enzyme. [ABSTRACT FROM AUTHOR]

The detailed analysis of atomic and magnetic structure has been performed by Mössbauer spectroscopy for polycrystalline Fe80Ga20 films of different thickness ranging from 20 nm to 200 nm. The films were deposited on Si(100) substrate using dual sputtering and evaporation method. Obtained CEMS spectra have been fitted with several Gaussian distributions of hyperfine magnetic field. The results point to the domination of BCC disordered A2 phase and the absence of DO3 and L12 phases in the films. Both hyperfine parameters and lattice constant reveal anomaly for 40 nm thick sample - presumably due to the change of the internal stress. Spin texture evolves from in-plane to out-of-the-plane configuration with increasing thickness. [ABSTRACT FROM AUTHOR]

The occurrence and microhabitat distribution of Dermocystidium percae on perch ( Perca fluviatilis) was investigated in four sites in the lower Thames Valley, south-east England. Fish were infected at all sites, with the highest prevalence occurring in a commercial fishery and the lowest in a large impounded water storage reservoir. The microhabitat distribution of D. percae cysts on the perch favoured the dorsal and anal fins, in contrast to previous studies, although a single occurrence on the gills was reported. The role of host stress on the prevalence of D. percae is discussed. [ABSTRACT FROM AUTHOR]

GaInSn, a eutectic alloy, has been successfully used in the Magneto-Thermofluid Research Laboratory at the University of California-Los Angeles and at the Princeton Plasma Physics Laboratory for the past six years. This paper describes the handling and safety of GaInSn based on the experience gained in these institutions, augmented by observations from other researchers in the liquid metal experimental community. GaInSn is an alloy with benign properties and shows considerable potential in liquid metal experimental research and cooling applications. [ABSTRACT FROM AUTHOR]