303 research outputs found

    Railway Tunnelling in Frozen Ground on Bothniabana

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    A new railway line was under construction in North-eastern Sweden, along the shoreline of the Gulf of Bothnia. The terrain consisted of Postglacial clay and silt valleys, and ridges of Precambrian bedrock, crossing the railway line. The railway level was about 20m below the ground surface. For the design of freezing, a freezing analysis was carried out to determine the pipeline depths and distances, to estimate the necessary time for freezing and to determine temperatures within the frozen zone. To estimate the deformations, displacements and safety level, a mechanical analysis of the tunnel cross-section was carried out. As input, the geometry of the soil layers, bedrock and temperature zones was given. Time- and temperature-dependent mechanical parameters were estimated for different soils and temperatures. The analysis was carried out for 12 phases simulating different phases during tunnelling. The estimated displacements for the tunnel arch were negligible, if the temperatures were at or below -15°C. The freezing was started in May 2002, and completed in September 2002. The tunnelling was started in September, and it was completed in November 2002, following with the casting of final liner. According to the experiences until now, the work has progressed successfully

    The effects of antioxidant vitamin supplementation on resistance exercise induced lipid peroxidation in trained and untrained participants

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    BACKGROUND: The theoretical benefits of using antioxidant vitamin supplements to quench oxygen free radicals appear large. High intensity aerobic-type exercise produces oxygen free radicals that can cause damage to lipid membranes (lipid peroxidation) that may lead to many problems such as the inactivation of cell membrane enzymes, the progression of degenerative diseases (cardiovascular disease and cancer) and lessening of the effectiveness of the immune system. The major function of vitamin E is to work as a chain-breaking antioxidant in a fat soluble environment. Little research has examined lipid peroxidation associated with high intensity resistance exercise or possible protective effects of antioxidant supplementation or the effects of training state. RESULTS: There were no significant group (trained vs untrained) or treatment (vitamin E vs placebo) effects found between the 4 groups assessed. There was only one significant difference found and that was in the main effect for time (F = 22.41, p < 0.01). CONCLUSIONS: The Resistance Exercise Test caused a significant increase in malondialdehyde in all 4 groups at 6 hours post exercise. There was no evidence that vitamin E supplementation was effective in reducing oxidative damage in comparison to the placebo group. As well, there was no difference between the trained and untrained groups with respect to their impact on lipid peroxidation measures

    Insights into neutralization of animal viruses gained from study of influenza virus

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    It has long been known that the binding of antibodies to viruses can result in a loss of infectivity, or neutralization, but little is understood of the mechanism or mechanisms of this process. This is probably because neutralization is a multifactorial phenomenon depending upon the nature of the virus itself, the particular antigenic site involved, the isotype of immunoglobulin and the ratio of virus to immunoglobulin (see below). Thus not only is it likely that neutralization of one virus will differ from another but that changing the circumstances of neutralization can change the mechanism itself. To give coherence to the topic we are concentrating this review on one virus, influenza type A which is itself well studied and reasonably well understood [1–3]. Reviews of the older literature can be found in references 4 to 7

    Graphene-based LbL deposited films: further study of electrical and gas sensing properties

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    Graphene-surfactant composite materials obtained by the ultrasonic exfoliation of graphite powder in the presence of ionic surfactants (either CTAB or SDS) were utilised to construct thin films using layer-by-layer (LbL) electrostatic deposition technique. A series of graphene-based thin films were made by alternating layers of either graphene-SDS with polycations (PEI or PAH) or graphene-CTAB with polyanions (PSS). Also, graphene-phthalocyanine composite films were produced by alternating layers of graphene-CTAB with tetrasulfonated nickel phthalocyanine. Graphene-surfactant LbL films exhibited good electric conductivity (about 0.1 S/cm) of semiconductor type with a band gap of about 20 meV. Judging from UV-vis spectra measurements, graphene-phthalocyanine LbL films appeared to form joint π-electron system. Gas sensing testing of such composite films combining high conductivity of graphene with the gas sensing abilities of phthalocyanines showed substantial changes (up to 10%) in electrical conductivity upon exposure to electro-active gases such as HCl and NH3

    Graphene-based LbL deposited films: further study of electrical and gas sensing properties

    Get PDF
    Graphene-surfactant composite materials obtained by the ultrasonic exfoliation of graphite powder in the presence of ionic surfactants (either CTAB or SDS) were utilised to construct thin films using layer-by-layer (LbL) electrostatic deposition technique. A series of graphene-based thin films were made by alternating layers of either graphene-SDS with polycations (PEI or PAH) or graphene-CTAB with polyanions (PSS). Also, graphene-phthalocyanine composite films were produced by alternating layers of graphene-CTAB with tetrasulfonated nickel phthalocyanine. Graphene-surfactant LbL films exhibited good electric conductivity (about 0.1 S/cm) of semiconductor type with a band gap of about 20 meV. Judging from UV-vis spectra measurements, graphene-phthalocyanine LbL films appeared to form joint π-electron system. Gas sensing testing of such composite films combining high conductivity of graphene with the gas sensing abilities of phthalocyanines showed substantial changes (up to 10%) in electrical conductivity upon exposure to electro-active gases such as HCl and NH3

    Enhanced Antibody Production in Clever-1/Stabilin-1-Deficient Mice

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    Clever-1, encoded by the Stab1 gene, is a scavenger and leukocyte trafficking receptor expressed by subsets of vascular and lymphatic endothelial cells and immunosuppressive macrophages. Monocyte Clever-1 also modulates T cell activation. However, nothing is known about the possible links between B cell function and Clever-1. Here, we found that Stab1 knockout mice (Stab1(-/-)) lacking the Clever-1 protein from all cells present with abnormally high antibody levels under resting conditions and show enhanced humoral immune responses after immunization with protein and carbohydrate antigens. Removal of the spleen does not abolish the augmented basal and post-immunization antibody levels in Clever-1-deficient mice. The increased IgG production is also present in mice in which Clever-1 is selectively ablated from macrophages. When compared to wildtype macrophages, Clever-1-deficient macrophages show increased TNF-alpha synthesis. In co-culture experiments, monocytes/macrophages deficient of Clever-1 support higher IgM production by B cells, which is blocked by TNF-alpha depletion. Collectively, our data show that the excessive inflammatory activity of monocytes/macrophages in the absence of Clever-1 results in augmented humoral immune responses in vivo

    Molecular organization of the tear fluid lipid layer

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    The tear fluid protects the corneal epithelium from drying out as well as from invasion by pathogens. It also provides cell nutrients. Similarly to lung surfactant, it is composed of an aqueous phase covered by a lipid layer. Here we describe the molecular organization of the anterior lipid layer of the tear film. Artificial tear fluid lipid layers (ATFLLs) composed of egg yolk phosphatidylcholine (60 mol %), free fatty acids (20 mol %), cholesteryl oleate (10 mol %), and triglycerides (10 mol %) were deposited on the air-water interface and their physico-chemical behavior was compared to egg-yolk phosphatidylcholine monolayers by using Langmuir-film balance techniques, x-ray diffraction, and imaging techniques as well as in silico molecular level simulations. At low surface pressures, ATFLLs were organized at the air-water interface as heterogeneous monomolecular films. Upon compression the ATFLLs collapsed toward the air phase and formed hemispherelike lipid aggregates. This transition was reversible upon relaxation. These results were confirmed by molecular-level simulations of ATFLL, which further provided molecular-scale insight into the molecular distributions inside and dynamics of the tear film. Similar type of behavior is observed in lung surfactant but the folding takes place toward the aqueous phase. The results provide novel information of the function of lipids in the tear fluid

    Multiple sclerosis in Finland 2018-Data from the national register

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    Objectives Finland is a high-risk multiple sclerosis (MS) region, but a national MS register has not existed until 2014. In this paper, we present the Finnish MS register variables and data collected by 31 December 2018. Materials and Methods Numbers and data counts of MS patients in the register (ICD-10 code G35) are presented. The disease types and proportion of patients receiving disease-modifying treatments (DMTs) were analysed in five hospital districts with most complete data sets. MS prevalence in Finland was estimated using administrative hospital discharge data as an additional resource. Results There were a total of 8722 MS patients in the Finnish MS register by 31 December 2018 (71.5% females). Mean age at MS diagnosis was 38.7 years and peak prevalence was at age 50-54 years. Disease course was relapsing remitting (RRMS) in 66.7%, secondary progressive (SPMS) in 13.5%, and primary progressive (PPMS) in 7.9% of the 5365 MS patients in the selected districts with most complete data. A total of 66.0% of RRMS patients, 19.6% of SPMS patients and 9.9% of PPMS patients were receiving DMTs. By combining MS register data with databases of those hospitals that had not joined the register, the nationwide prevalence estimate was between 10 and 11 thousand patients (corresponding to crude prevalence 180-200/100 000). Conclusions The Finnish MS register is currently used in 15/21 Finnish hospital districts. By register integration into the electronic patient files, the coverage of the register has increased to approximately 80% of the estimated Finnish MS population.Peer reviewe
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