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Multicenter collaborative networks are essential for advancing research and improving clinical care for a variety of conditions. Research networks are particularly important for central nervous system infections, which remain difficult to study due to their sporadic occurrence and requirement for collection and testing of cerebrospinal fluid. Establishment of long-term research networks in resource-limited areas also facilitates diagnostic capacity building, surveillance for emerging pathogens, and provision of appropriate treatment where needed. We review our experience developing a research network for encephalitis among twelve hospitals in five Peruvian cities since 2009. We provide practical suggestions to aid other groups interested in advancing research on central nervous system infections in resource-limited areas.

The legs of Drosophila are divided into segments along the proximodistal axis by flexible structures called joints. The separation between segments is already visible in the imaginal disc as folds of the epithelium, and cells at segment boundaries have different morphology during pupal development. We find that Notch is locally activated in distal cells of each segment, as demonstrated by the restricted expression of the Enhancer of split mbeta gene, and is required for the formation of normal joints. The genes fringe, Delta, Serrate and Suppressor of Hairless, also participate in Notch function during leg development, and their expression is localised within the leg segments with respect to segment boundaries. The failure to form joints when Notch signalling is compromised leads to shortened legs, suggesting that the correct specification of segment boundaries is critical for normal leg growth. The requirement for Notch during leg development resembles that seen during somite formation in vertebrates and at the dorsal ventral boundary of the wing, suggesting that the creation of boundaries of gene expression through Notch activation plays a conserved role in co-ordinating growth and patterning.

The basic helix-loop-helix proteins of the Enhancer of split complex constitute a link between activation of the transmembrane receptor Notch and the resulting effects on transcription of downstream genes. The Suppressor of Hairless protein is the intermediary between Notch activation and expression of all Enhancer of split genes even though individual genes have distinct patterns of expression in imaginal discs. A comparison between the phenotypes produced by Notch, Suppressor of Hairless and Enhancer of split mutations in the wing and thorax indicate that Suppressor of Hairless and Notch requirements are indistinguishable, but that Enhancer of split activity is only essential for a subset of developmental processes involving Notch function. Likewise, the ectopic expression of Enhancer of split proteins does not reproduce all the consequences typical of ectopic Notch activation. We suggest that the Notch pathway bifurcates after the activation of Suppressor of Hairless and that Enhancer of split activity is not required when the consequence of Notch function is the transcriptional activation of downstream genes. Transcriptional activation mediated by Suppressor of Hairless and transcriptional repression mediated by Enhancer of split could provide greater diversity in the response of individual genes to Notch activity.

Ti‐6Al‐4V alloy has attracted increasing applications as a metallic biomaterial in recent years thanks to its good corrosion resistance and biocompatibility. However, the poor corrosion‐wear resistance of the alloy is thus a major concern to potential users. In this paper, the electrochemical noise technique is used as an on‐line tool to investigate the corrosion‐wear behavior of untreated and Mo‐N modified Ti‐6Al‐4V alloy sliding against corundum in Hanks' and sodium phosphate solutions.

The reorientation of as-deposited randomly oriented sulphur-deficient MoSxcoatings during fretting wear tests has been investigated by X-ray diffraction (XRD), Scanning Electron Microscope and Transmission Electron Microscope. The driving force for the reorientation seems to be the plastic deformation induced by the tangential friction force during fretting tests. The evolution from an as-deposited randomly orientation into a basal one occurs above a threshold normal load and fretting frequency. This reorientation results in a lowering of the coefficient of friction as well as in a high resistance to humidity, but unfortunately a high wear rate is noticed. The effect of normal load and fretting frequency on that reorientation process in MoSxcoatings is discussed.

This paper describes an investigation on the failure of a large leaded bronze bearing that supports a nine-ton roller of a plastic calendering machine. At the end of the normal service life of a good bearing, which lasted for seven years, a new bearing was installed. However the new one failed catastrophically within a few days, generating a huge amount of metallic wear debris and causing pitting on the surface of the cast iron roller. Following the failure, samples were collected from both good and failed bearings. The samples were analyzed chemically and their microstructures examined. Both samples were subjected to accelerated wear tests in a laboratory type pin-on-disk apparatus. During the tests, the bearing materials acted as pins, which were pressed against a rotating cast iron disk. The wear behaviors of both bearing materials were studied using weight loss measurement. The worn surfaces of samples and the wear debris were examined by light optical microscope, scanning electron microscope, and energy-dispersive x-ray microanalyzer. It was found that the laboratory pin-on-disk wear data correlated well with the plant experience. It is suggested that the higher lead content (∼18%) of the good bearing compared with 7% lead of the failed bearing helped to establish a protective transfer layer on the worn surface. This transfer layer reduced metal-to-metal contact between the bearing and the roller and resulted in a lower wear rate. The lower lead content of the failed bearing does not allow the establishment of a well-protected transfer layer and leads to rapid wear.

Formation and separation of thin porous silicon films from the original substrate in combination with the transfer of such films onto a cheap foreign substrate for the photovoltaic application provides a straightforward way to cost reduction. Separation of the porous silicon film from the reusable p⁺ silicon substrate is achieved by electrochemical etching of silicon under specific HF concentration and current densities. The effect of HF concentration on film separation is studied. It is found that film separation is possible only for HF concentration of 22% and lower. Addition of DI water in the solution results in the formation of a thick porous silicon layer without separation from the substrate during 10 minutes. A theoretical explanation has been given to describe the phenomena of porous silicon film separation.

The current state of the art of the experimental approach to fretting is discussed. The mechanical response of fretting equipment is analysed to establish the limits of the reliable use of fretting rigs. The effect of stiffness and dynamic response of fretting test rigs are extensively discussed, and a simple one freedom-degree model is proposed to describe, in a first approach, the response of the tangential force measuring systems.

The investigation of the tribological performance of MoS2-based coatings in air of high humidity is critical for the future use of such low-friction and high-wear-resistant coatings in ambient air. Sulfur-deficient MoSxcoatings with a basal plane (x= 1.3) and a random (x= 1.8) crystallographic orientation were produced by planar magnetron sputtering. The coefficient of friction and the wear loss of MoSxcoatings in comparison with TiN and amorphous TiB2coatings were investigated in bi-directional sliding fretting tests performed in ambient air of different relative humidity. The wear rate expressed as a volumetric loss per unit of dissipated energy was determined. From these results, the best friction and wear performance was achieved with basal-plane-oriented MoSxcoatings tested at a relative humidity in the range of 10-50%. A coefficent of friction of 0.06-0.08 and a wear rate of 4 × 103μm3J-1, at a normal load of 1 N and a fretting frequency of 10 Hz, were recorded for that type of MoSxcoatings.

The electrolytic codeposition of micro- and nano-sized particles with aluminum from a nonaqueous electrolyte is investigated. SiC, SiO2, Al2O3, TiB2and hexagonal BN particles were codeposited with aluminium from an AlCl3/dimethylsulfone (DMSO2) electrolyte. The effect of particle concentration and current density on the codeposition rate of SiO2with aluminium was investigated. The codeposition of the various particles with Al from AlCl3:DMSO2solutions is very high. The amount of codeposited particles is Langmuir dependent on the particle concentration in the electrolyte. In contrast, the effect of the current density on the amount of codeposited SiO2is small.

Proteomics is a modern, rapidly developing branch of biology aimed at the integral study of genome expression as the diversity of proteins. Proteomics is based on a variety of methods allowing one to isolate, detect, identify, and to analyze quantitatively thousands of proteins comprising the cellular proteome. Up to date, high-resolution two-dimensional electrophoresis is the key proteomic technology; it allows one to analyze simultaneously the protein composition of cells and tissues and to reveal quantitative and qualitative changes in the synthesis of proteins modulating multiple cell functions. The present status of proteomic technologies, i.e., of 2D electrophoresis, with accompanying methods of identification of proteins at the maps obtained, as well as a brief description of organization of human mouse 2D database suggested for global analysis of genome expression in normal and pathological conditions (http:/biobase.dk/cgi-bin/celis) are discussed.

The function of extramacrochaetae is required during the development of the Drosophila wing in processes such as cell proliferation and vein differentiation. extramacrochaetae encodes a transcription factor of the HLH family, but unlike other members of this family, Extramacrochaetae lacks the basic region that is involved in interaction with DNA. Some phenotypes caused by extramacrochaetae in the wing are similar to those observed when Notch signalling is compromised. Furthermore, maximal levels of extramacrochaetae expression in the wing disc are restricted to places where Notch activity is higher, suggesting that extramacrochaetae could mediate some aspects of Notch signalling during wing development. We have studied the relationships between extramacrochaetae and Notch in wing development, with emphasis on the processes of vein formation and cell proliferation. We observe strong genetic interaction between extramacrochaetae and different components of the Notch signalling pathway, suggesting a functional relationship between them. We show that the higher level of extramacrochaetae expression coincides with the domain of expression of Notch and its downstream gene Enhancer of split-m(beta). The expression of extramacrochaetae at the dorso/ventral boundary and in boundary cells between veins and interveins depends on Notch activity. We propose that at least during vein differentiation and wing margin formation, extramacrochaetae is regulated by Notch and collaborates with other Notch-downstream genes such as Enhancer of split-m(beta).

The use of electrochemical impedance spectroscopy (EIS) for the in situcontrol of the electrolytic codeposition of Ni/SiO2and Ni/SiC was investigated. An attempt was made to clarify why silica particles hardly codeposit in comparison to silicon carbide particles. It was found that the presence of SiO2and SiC particles influences the metal deposition process in different ways. SiC particles that are being embedded in the growing metal layer cause an apparent decrease in the electrode surface area, probably due to blocking off a part of the surface by partly engulfed particles. In the case of SiO2particles, which embed in the metal matrix to a very limited extent, no blocking was observed. It was found that the presence of particles in the solution causes an apparent increase in the electrode surface area, probably due to increased surface roughness.

The Notch signalling pathway regulates cell fate choices during both vertebrate and invertebrate development. In the Drosophila wing disc, the activation of Notch by its ligands Delta and Serrate is required to make the dorsoventral boundary, where several genes, such as wingless and cut, are expressed in a 2- to 4-cell-wide domain. The interactions between Notch and its ligands are modulated by Fringe via a mechanism that may involve post-transcriptional modifications of Notch. The ligands themselves also help to restrict Notch activity to the dorsoventral boundary cells, because they antagonise the activation of the receptor in the cells where their expression is high. This function of the ligands is critical to establish the polarity of signalling, but very little is known about the mechanisms involved in the interactions between Notch and its ligands that result in suppression of Notch activity. The extracellular domain of Notch contains an array of 36 EGF repeats, two of which, repeats 11 and 12, are necessary for direct interactions between Notch with Delta and Serrate. We investigate here the function of a region of the Notch extracellular domain where several missense mutations, called Abruptex, are localised. These Notch alleles are characterised by phenotypes opposite to the loss of Notch function and also by complex complementation patterns. We find that, in Abruptex mutant discs, only the negative effects of the ligands and Fringe are affected, resulting in the failure to restrict the expression of cut and wingless to the dorsoventral boundary. We suggest that Abruptex alleles identify a domain in the Notch protein that mediates the interactions between Notch, its ligands and Fringe that result in suppression of Notch activity.

The surface force between a silica sphere and a copper electrode was measured in concentrated solutions of MgSO4 with an atomic force microscope as a function of the electrode potential. The interaction between the two surfaces was compared with the DLVO theory, and the surface potential of the copper electrode was determined as a function of the cathodic overpotential. The potential of zero charge of the copper electrode was identified in this way. This was found to correspond to the potential of zero charge obtained from the differential capacitance minimum. Moreover, the influence of the pH on the surface force between silica and copper was examined and the presence of a chemically adsorbed oxygen layer on copper was deduced from force measurements at high pH.

The nuclear proteins Spalt and Spalt-related belong to a conserved family of transcriptional regulators characterised by the presence of double zinc-finger domains. In the wing, they are regulated by the secreted protein Decapentaplegic and participate in the positioning of the wing veins. Here, we identify regulatory regions in the spalt/spalt-related gene complex that direct expression in the wing disc. The regulatory sequences are organised in independent modules, each of them responsible for expression in particular domains of the wing imaginal disc. In the thorax, spalt and spalt-related are expressed in a restricted domain that includes most proneural clusters of the developing sensory organs in the notum, and are regulated by the signalling molecules Wingless, Decapentaplegic and Hedgehog. We find that spalt/spalt-related participate in the development of sensory organs in the thorax, mainly in the positioning of specific proneural clusters. Later, the expression of at least spalt is eliminated from the sensory organ precursor cells and this is a requisite for the differentiation of these cells. We postulate that spalt and spalt-related belong to a category of transcriptional regulators that subdivide the thorax into expression domains (prepattern) required for the localised activation of proneural genes.

The basic helix-loop-helix transcription factor c-Myc is a potent trigger of programmed cell death when overexpressed during late oligodendrocyte development in transgenic mice. Here we provide evidence that c-Myc can act synergistically with the Pit, Oct, Unc homeodomain transcription factor Oct-6 to produce myelin disease pathogenesis in transgenic mice. More than 70% of c-myc/Oct-6 bitransgenic mice, obtained from crosses between phenotypically normal heterozygous mice of various My (c-Myc) and Oc (Oct-6) transgenic strains that express c-myc and oct-6 transgenes under transcriptional control of the myelin basic protein gene, developed severe neurological disturbances characterized by action tremors, recurrent seizures, and premature death. Affected bitransgenic mice exhibited multiple hypomyelinated lesions in the white matter that did not stain with myelin-specific antibodies against myelin basic protein, proteolipid protein, CNPase, and myelin-associated glycoprotein. The mice also exhibited a larger number of terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling positive cells in the white matter as well as ultrastructural evidence of glial cell death and astrogliosis. These observations indicate that the myelin lesions observed in the c-myc/oct-6 bitransgenic mice result from the untimely programmed cell death of oligodendroglia and that the c-myc and oct-6 transgenes act synergistically in producing the lesions.

Intermediate filaments are general constituents of the cytoskeleton. The function of these structures and the requirement for different types of intermediate filament proteins by individual cells are only partly understood. Here we have addressed the role of specific intermediate filament protein partnerships in the formation of intermediate filaments in astrocytes. Astrocytes may express three types of intermediate filament proteins: glial fibrillary acidic protein (GFAP), vimentin, and nestin. We used mice with targeted mutations in the GFAP or vimentin genes, or both, to study the impact of loss of either or both of these proteins on intermediate filament formation in cultured astrocytes and in normal or reactive astrocytes in vivo. We report that nestin cannot form intermediate filaments on its own, that vimentin may form intermediate filaments with either nestin or GFAP as obligatory partners, and that GFAP is the only intermediate filament protein of the three that may form filaments on its own. However, such filaments show abnormal organization. Aberrant intermediate filament formation is linked to diseases affecting epithelial, neuronal, and muscle cells. Here we present models by which the normal and pathogenic functions of intermediate filaments may be elucidated in astrocytes.

Members of the phospholipase D (PLD) superfamily are defined by the conserved HXKXXXXD motif, which is essential for the catalytic function of mammalian PLD. PLD enzymes are thought to play roles in signal transduction and membrane vesicular trafficking in mammalian cells. Here we describe a 54-kDa novel murine polypeptide (designated SAM-9) that is predicted to be a membrane-associated member of the PLD superfamily. SAM-9 shares 40, 30, and 29% amino acid identity with potential orthologs, in vaccinia virus, Caenorhabditis elegans, and Dictyostelium discoideum, respectively, and belongs to a subclass of PLD homologs in which the second HXKXXXXD motif is imperfect and harbors a conserved Asp to Glu substitution. The sam-9 gene has more than eight exons, and the two HXKXXXXD motifs are encoded by two highly conserved exons. The expression of the sam-9 gene is greater in the brain than in non-nervous tissue and appears to be predominantly of neuronal origin. sam-9 expression is pronounced in mature neurons of the forebrain and appears to be turned on at late stages of neurogenesis as revealed by in situ hybridization analysis of sam-9 expression during postnatal development of the hippocampal formation and the primary somatosensory cortex.

Fibroblasts with smooth muscle differentiation are frequently derived from human breast tissue. Immunofluorescence cytochemistry of a fibroblast-associated antigen recognized by a monoclonal antibody (MAb), 1B10, was analyzed with a view to discriminating smooth muscle differentiated fibroblasts from vascular smooth muscle cells. The antigen was detected on the cell surface and in cathepsin D-positive and acridine orange-accumulating vesicular compartments of fibroblasts. Ultrastructurally, the antigen was revealed in coated pits and in endosomal and lysosomal structures. 1B10 recognized three major brands migrating at apparent Mr of 38,000, 45,000, and 80,000, in addition to many minor bands between Mr 45,000 and 97,000, including Mr 52,000. The Mr 45,000 and 38,000 were associated with the cell membrane and Mr 52,000 as well as Mr 38,000 were associated with the lysosomes. The 1B10 immunoreactivity was specific to fibroblasts and smooth muscle differentiated fibroblasts within the context of vascular smooth muscle cells.

In the present paper, data on the codeposition of fine Al2O3 particles with copper from an acidified copper sulphate bath and on the codeposition of Au-Al2O3 from a gold cyanide bath are compared. Based on these results, it is shown that the mechanism of codeposition of inert particles is similar in both systems. The reduction of ions adsorbed on alumina particles is the rate-determining step. The rate of codeposition is further dependent on the mass transport to the electrode and on the applied voltage.

The wear behaviour of a-C:H coatings in ambient air up to maximum temperatures of 300 °C is reported. A simultaneous tribological and thermal load was imposed using a low-amplitude oscillatory sliding test in combination with a heatable specimen holder. The investigation showed that the tribological behaviour of the a-C:H coatings changed considerably at elevated temperatures: the coefficient of friction decreased and the wear scars became larger and deeper, indicating a more severe wear process at elevated temperatures. Under the present test conditions tribological behaviour started to change around 100 °C. On previously annealed samples, however, the wear properties at room temperature remained stable up to annealing temperatures of 300 °C. The temperature dependent wear behaviour of diamond-like carbon has been linked to the surface properties of these materials which become modified at relatively low temperatures where bulk properties are known to remain unchanged.

SummaryComposite plating may nowadays be considered as a well-established industrial technology for the synthesis of some types of composite coatings like Ni-SiC in the automotive industry. Potentialities of that composite plating process are numerous but new developments are fastidious and expensive. This paper highlights some recent progresses made in determining the forces bringing and keeping particles in the neighbourhood of electrodes and in detecting the trajectory of particles near electrodes. The last possibility opens the way to the development of an electrochemical sensor suitable for on-line process control in composite plating.

Summary The complete long terminal repeat (LTR) nucleotide sequence of the chimpanzee foamy virus isolate SFV-6 was determined. Its 1761-bp size makes it the longest LTR reported to date among all retroviruses. Since the length of its LTR is similar to that of other simian isolates while its sequence homology is closer to that of HFV, SFV-6 genetic structure appears to be intermediate between simian and human foamy viruses. Transient expression assays demonstrate that SFV-6 encodes a transactivator of viral gene expression directed either by its own LTR or by heterologous promotors like HFV and HIV-1 LTRs. Our data also provide evidence for cross-transactivation between SFV-6 and HFV.