The transfer function and impulse response of photorefractivetwo-beam coupling

The transfer function and impulse response of photorefractive two-beam coupling are derived in the undepleted pump approximation. For sufficiently strong coupling ΓL, the impulse response features a broad delayed output pulse. In the limits of negligible and strong absorption αL, this coupling threshold reads ΓL_thr=4 and Γ_thr=2α, respectively. The time delay and pulse height are functions of the coupling ΓL, the photorefractive time constant τ, and the effective absorption αL. Experiments on a BaTiO₃ crystal measuring the absoluted square of its transfer function and the impulse response are used to determine the coupling and time constant     

Clinical usefulness of helical scanning CT (HES-CT) for orbital lesion

As part of an investigation of the structural requirements for the induction, by phenobarbital-type inducers, of a coordinate pleiotropic response consisting of increases in hepatic cytochrome P450 2B (P450 2B) activity, increases in other phase I and II enzyme activities, and liver hypertrophy, we have examined a series of analogues of phenobarbital in which the ethyl/phenyl substitution at the sp3 carbon of the parent molecule was kept constant while the heterocyclic portion of the molecule was modified. The induction of hepatic P450 2B protein and ethoxy-, pentoxy-, and (benzyloxy)resorufin O-dealkylation activities, and epoxide hydration activity and liver/body weight ratio increase were examined in male F344/NCr rats fed the various congeners for 14 days at doses equimolar to 500 ppm phenobarbital. Increases in the measured parameters were maximal in rats fed phenobarbital or 5-ethyl-5-phenylhydantoin. The responses to primidone or 2-ethyl-2-phenylsuccinimide were approximately 65% of maximal, while glutethimide yielded a response approximately 50% of maximal. Induction of this response in rats fed the ring-opened and decarboxylated analogues, (ethylphenylacetyl)urea and 2-ethyl-2-phenylmalonamide, were < 25% of maximal. 5-Ethyl-5-phenyloxazolidinedione caused minimal increases in the measured end points when administered at a dose equimolar to 500 ppm phenobarbital. The profound differences among the congeners in ability to induce P450 2B protein and associated catalytic activities were not due to differences in food consumption by the various groups of rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

A single STAT recruitment module in a chimeric cytokine receptor complex is sufficient for STAT activation

We established a system of receptor chimeras that enabled us to induce heterodimerization of different cytoplasmic tails. Fusion constructs were created that are composed of the extracellular parts of the interleukin-5 receptor alpha and beta chains, respectively, and the transmembrane and intracellular parts of gp130, the signal transducing chain of the interleukin-6 receptor complex. In COS-7 transfectants we observed a dose-dependent interleukin-5-inducible STAT1 activation for which the presence of both the alpha and the beta chain chimera was needed. No STAT activity was detected if one of the cytoplasmic tails of the receptor complex was deleted, indicating that STAT activity resulted from a receptor dimer rather than from higher receptor aggregates. We further investigated whether dimerization of STAT1 depends on the juxtaposition of two STAT recruitment modules in a receptor complex. We show that a receptor dimer with only a single STAT1 docking site was still able to lead to STAT1 activation. This indicates that the formation of a paired set of STAT binding sites in a receptor complex is not the prerequisite for STAT factor dimerization. Our findings are discussed in view of alternative STAT dimerization models.     

Proteomics Profiling of Neuron-Derived Small Extracellular Vesicles from Human Plasma: Enabling Single-Subject Analysis

Small extracellular vesicles have been intensively studied as a source of biomarkers in neurodegenerative disorders. The possibility to isolate neuron-derived small extracellular vesicles (NDsEV) from blood represents a potential window into brain pathological processes. To date, the absence of sensitive NDsEV isolation and full proteome characterization methods has meant their protein content has been underexplored, particularly for individual patients. Here, we report a rapid method based on an immunoplate covalently coated with mouse monoclonal anti-L1CAM antibody for the isolation and the proteome characterization of plasma-NDsEV from individual Parkinson’s disease (PD) patients. We isolated round-shaped vesicles with morphological characteristics consistent with exosomes. On average, 349 ± 38 protein groups were identified by liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis, 20 of which are annotated in the Human Protein Atlas as being highly expressed in the brain, and 213 were shared with a reference NDsEV dataset obtained from cultured human neurons. Moreover, this approach enabled the identification of 23 proteins belonging to the Parkinson disease KEGG pathway, as well as proteins previously reported as PD circulating biomarkers.     

Design of Flux Observer Robust to Interior Permanent-Magnet Synchronous Motor Flux Variation

This paper presents a modified flux observer which is robust to the variation of the permanent-magnet flux linkage of an interior permanent-magnet synchronous motor (IPMSM). The IPMSM is driven by a current-regulated inverter, where the d-q axis currents are controlled by two proportional and integral controllers with feedforward cross-coupling decoupling terms. The integrator outputs of the current regulator reflecting flux errors are used to compensate the flux variation according to the operating temperature and manufacturing tolerance. The proposed flux observer shows satisfactory performance not only in maximum torque per ampere operating region but also in flux weakening region. The experimental results reveal the effectiveness of the proposed observer.     

Comparative studies on cytotoxic effects of dental amalgams and alternative alloys according to ISO standards in vitro

Deleterious effects of dental alloys, especially those of dental amalgams, have become an important issue in current discussions on biomaterials. Cytotoxicity and further related risks of amalgams are discussed in a controversial way in the literature without leading to a final conclusion. There is still a need for basic clinical and pre-clinical research, especially with respect to the wide distribution of dental amalgams. Standardized methods of cytotoxicity testing have been established by the ISO. It was the aim of the present study to detect and compare possible cytotoxic effects of dental amalgams and alternative non-amalgam alloys in vitro. According to the ISO standards, direct contact tests and extract dilution tests were performed using the cell lines HeLa and L-929 as well as primary isolated human fibroblasts, a relevant cell type of the human gingiva. For direct contact tests the samples were fixed on thermanox discs. Zn and Ni-chloride in defined molar concentrations were used as positive controls in the extract dilution tests, while copper was the positive control in the direct contact tests. The tested amalgam was a Non-Gamma-2 amalgam. For extract dilution tests sixteen extraction dilutions were performed. The different cell types were incubated with the extracts in 96-well microtitre plates. MTT-testing was performed to evaluate the effects on cellular metabolism. The BrdU labelling index was determined with the help of EIA methods to analyse the effects of the extracts on the cellular proliferation at DNA synthesis level. The morphological status of the cells seeded on the materials (direct contact test) were studied with the help of light microscopy. No cytotoxic effects of formerly extracted dental amalgam was found, although fresh amalgam elicited a significant cytotoxic effect, in general the non-amalgams have to be regarded as non cytotoxic. The negative control and the non-amalgams elicited no measurable cytotoxicity in the indirect contact assays, independent of the number of extraction dilutions. This applied to all cell types studied. The tested amalgam also gave a significant cytotoxic effect in the MTT-assays, while in addition a significant reduction of BrdU incorporation after incubation with the extracts of the first dilution series, compared to the silicone control was found. The effects were reduced after an incubation with the extracts of the higher dilution series. It is suggested by the presented results that amalgams might have cytotoxic effects, especially when being freshly applied. The cytotoxic effects were no longer detectable after extraction procedures. Nevertheless, a negative effect around such amalgams must be considered. The insights provided by the present studies might be helpful for a rational choice of dental materials.     

Effect of Process Parameters on the Geometry of Composite Parts Reinforced by Through-the-Thickness Tufting

Inserting discrete through-the-thickness reinforcing elements such as fibrous tufts into a composite laminate may increase dramatically its damage tolerance and impact resistance. The three-dimensional fibre architecture generated locally by such elements (sometimes referred to as micro-fasteners) has been demonstrated to slow down or arrest altogether delamination crack growth. Where a closed, matched tool is used for infusion and cure, the insertion of tufts may result in a local increase in fibre volume fraction. On the other hand, when a flexible sealant bag or film is used, the extra fibrous yarn may cause an increase of the laminate thickness, with potential alteration of the component geometry. The latter effect may impact upon the component performance, especially if aerodynamic surfaces are involved, and therefore needs systematic quantification. This paper quantifies the alteration in thickness of a flat laminate made with non-crimp carbon fabric and reinforced with carbon tufts using a range of material and manufacturing variables. A design of experiments approach is applied and a 3D laser scanner used to gather reliable data to identify those parameters most likely to influence the change of geometry (including yarn weight, tuft areal density and tuft angle). A case study is presented to relate the experimental findings to the case of a 900 mm long, double curvature carbon fibre tufted T-stringer made with a 3D woven π-section.     

Inflammatory and cytotoxic responses of an alveolar-capillary coculture model to silica nanoparticles: comparison with conventional monocultures

Background  

To date silica nanoparticles (SNPs) play an important role in modern technology and nanomedicine. SNPs are present in various materials (tyres, electrical and thermal insulation material, photovoltaic facilities). They are also used in products that are directly exposed to humans such as cosmetics or toothpaste. For that reason it is of great concern to evaluate the possible hazards of these engineered particles for human health. Attention should primarily be focussed on SNP effects on biological barriers. Accidentally released SNP could, for example, encounter the alveolar-capillary barrier by inhalation. In this study we examined the inflammatory and cytotoxic responses of monodisperse amorphous silica nanoparticles (aSNPs) of 30 nm in size on an in vitro coculture model mimicking the alveolar-capillary barrier and compared these to conventional monocultures.     

Thermoelectric Properties of Polyaniline Films with Different Doping Concentrations of (±)-10-Camphorsulfonic Acid

The temperature dependence of the thermoelectric properties was investigated for polyaniline (PANI) films doped with different concentrations of (±)-10-camphorsulfonic acid (CSA) with molar ratio x of CSA to two phenyl-nitrogen units of x = 1 to 0.2. All PANI-CSA films exhibit p-type conduction. The temperature dependence of the electrical conductivity of the films with low CSA concentrations is consistent with a transport mechanism of variable-range hopping. On the other hand, the Seebeck coefficient above room temperature shows a linear increase with temperature, attributed to the metallic nature of PANI-CSA. As the CSA concentration decreases, the absolute value of the Seebeck coefficient increases while the electrical conductivity extremely decreases, probably due to the changes not only in the carrier concentration but also in the degree of structural disorder. The power factor increases monotonically with increasing CSA concentration toward x = 1 (the maximum limit). The thermal conductivity value of CSA-PANI film with x = 1 is as low as about 0.20 W m^?1 K^?1 in the through-plane direction and about 0.67 W m^?1 K^?1 in the in-plane direction. The thermoelectric figure of merit ZT in the in-plane direction is estimated to be approximately 1 × 10^?3 for x = 1.