400 research outputs found

    Electromechanical characterization of piezoelectric actuators subjected to a variable preloading force at cryogenic temperature

    No full text
    A dedicated apparatus was designed and constructed for studying the electromechanical behavior of prototype piezoelectric actuators subjected to a variable preloading force at cryogenic temperatures. This device was successfully used for testing a piezoelectric actuator of PICMA type from PI™, for T in the range 2 K-300 K. The dielectric properties as well as dynamic properties were measured including the actuator characteristics when used as force sensor. The corresponding data are reported and discussed

    Bioclimatic modelling in the holocene and in future warming scenarios in Arbutus unedo L.

    Get PDF
    Growing forests wildfires in Portugal are an increasing concern since forests in the Mediterranean region are vulnerable to recent global warming. Long-term negative effects are expected on the vegetation with the coming increasing drought. The strawberry tree (Arbutus unedo L.) displays potential to be a successfully business-like cultured in several regions of Portugal and southern Europe, as it is well adapted to climate and soils. In Portugal, this species has been used by local populations particularly for spirit production and for fruit consumption, although it has different possible commercial uses, from processed and fresh fruit production to ornamental, pharmaceutical and chemical applications. In addition, due to its pioneer status, it is valuable for land recovery and desertification avoidance, besides being fire resistant. The available strawberry tree’s data is presence-only. For modelling purposes, a set of placements within the landscape of interest (Portugal) was applied. The species, observed in 318 plots, together with a vector of environmental covariates (7 bioclimatic attributes, slope and altitude) and a defined background were used for modeling purposes. Maxent 3.4.1 was the used software, where the estimated quantity is the probability of the presence of the species, conditioned on the environment. Maxent uses the environmental covariate data from the occurrence records and the background sample, to estimate the ratio between the conditional density of the covariates at the presence sites and the marginal (i.e., unconditional) density of covariates across the study area and so, estimating the relative suitability of one place vs. another. Three different climate scenarios (control run; 2050 and 2070) were tested for two emission scenarios (RCP 4.5 and RCP 8.5, WorldClim), besides the past, 6,000 BP (Mid-Holocene). The reduction of habitat suitable for this species is very significant in the southern regions, even for the best warming scenario (RCP 4.5) in 2050. Central and Northern mountain regions are predicted refuge for this species. Forest policies and management should consider the impact of climate change on the usable areas for forestry, seeing a case-study species particularly adapted to the Mediterranean regions and wildfires, such as strawberry tree. The distribution of the species in the Middle Holocene agrees with previous genetic and fossils studies in the region, which supported two putative refuges for the species since the Last Glacial Maximum and a cryptic refugia in the East-Central mountain region.info:eu-repo/semantics/publishedVersio

    Analysis of Downhole Logs, Leg 57, Deep Sea Drilling Project

    Get PDF
    All sites drilled on Leg 57 were logged as weather conditions permitted. The logging was done by the Singapore office of Schlumberger, and because of short notice the special logging tools required to pass through the Challenger drill pipe were not available. The standard centralizer, excentralizer, and caliper tools were not appropriate, and those modified aboard ship were not completely satisfactory. In addition, we suspected that vertical motion from the ship's heave degraded the quality of logs. Both the sonic and neutron density tools were operated beyond their normal working ranges. Despite these operational difficulties, the logs from different runs in a hole, both repeat sections and runs with different tools, show generally the same features. Over intervals of 5 to 10 meters the field logs seem to be good indicators of the physical character of the section penetrated (Carson and Bruns, this volume). The recovery of continuous core as well as logs differs from normal industrial drilling practice, in which a major purpose of logging is to establish lithology. Since lithology is best established by direct examination, the log analysis focused less on identifying a specific lithology than on continuous measurement of in situ physical properties, especially at Sites 438, 439, and 440, where recovery was good. However, the logs were used to establish the lithology of missing intervals, especially at Site 441, where recovery was poor. Lithology and physical properties aspects of the log analysis are covered in the individual site chapters and in a comparative analysis of laboratory measurements of physical properties and logged physical parameters (Carson and Bruns, this volume). In the present chapter we concentrate on log precision, correlation of key horizons in seismic records and core lithology, and on fracturing as indicated by the logs. We do this by using the results of a study of corrected logs and the derivative products from computer programs developed by the Scientific Software Corporation (SSC) and Technology Research Center and of corrected logs from Schlumberger (available from DSDP)

    Volatile Composition and Outgassing in C/2018 Y1 (IWAMOTO): Extending Detection Limits for High-Resolution IR Cometary Spectroscopy at the NASA-IRTF

    Get PDF
    We used iSHELL, the powerful high-resolution ( /~ 40,000) cross-dispersed IR spectrograph at the NASA-IRTF to measure the native ice composition and outgassing of moderately bright, long-period comet C/2018 Y1 (Iwamoto) (hereafter Y1) within weeks of its discovery. We measured production rates for H2O, and production rates and abundance ratios relative to H2O for eight trace molecules, including the most complete measure of cometary CH4 achieved to date. Compared with mean abundances measured among comets, our study revealed enriched CH3OH and C2H6 yet depleted CO and C2H2, perhaps indicating highly efficient H- atom addition on interstellar grains prior to their incorporation into the nucleus. The combined high spectral resolving power and broad spectral coverage of iSHELL allowed characterizing cometary composition using only three instrument settings, and its long-slit coverage allowed comparing the spatial distributions of molecular emissions and dust continuum

    Immunologic factors in patients with chronic polypoid sinusitis

    Get PDF
    Nasal polyposis is the benign protrusion of soft tissue into the nasal cavity, with multifactorial origin. This study is designed to examine the suggested role of IgE and CD4 and CD8 lymphocytes in the pathogenesis of nasal polyposis. Blood samples were taken from 32 patients with chronic polypoid sinusitis and 32 controls. CD4 and CD8 total lymphocyte count were determined by flow cytometry and the level of serum IgE was measured by ELISA. Nasal discharge samples were also collected for determining IgE level in both patients and controls during surgery. In 68.8% of patients a history of allergy was present. The level of nasal discharge IgE was significantly higher (p 0.05). CD8 concentration and blood lymphocytes were significantly higher (

    Immunologic factors in patients with chronic polypoid sinusitis

    Get PDF
    No Abstract

    Molecular Modeling Simulation Study of Interactions in Starch/Poly(acrylic acid) Blend

    Get PDF
    In this work we have studied the nature of interactions between starch and poly(acrylic acid) by using semi-empirical AM1 and PM3 methods. Theoretical computations involved the determination of optimal geometries, binding energies and vibrational frequencies of the blended polymers. Calculations are performed for four pairs of complexes of glucose (Glu) in starch and acrylic acid (mAA) in poly(acrylic acid) PAA. Based on results of calculation, the binding energies show negative values, which indicate that the interactions of glucose and acrylic acid are favorable at the lower energy. This means that the interactions of starch and PAA are stable. Vibrational frequency analysis of hydroxyl OH and carboxyl C=O groups of the 1Glu–1mAA, 1Glu–2mAA and 1Glu–3mAA complexes with single hydrogen bond showed that the stretching of these groups shifts to a lower wave number due to the formation of hydrogen bonds. Keywords:Polymer blends, AM1, PM3

    Seroprevalence of Toxoplasma gondii

    Get PDF
    Toxoplasma gondii is an obligate intracellular protozoan parasite causing toxoplasmosis in animals and humans. Primary maternal infection with toxoplasmosis during pregnancy is frequently associated with transplacental transmission to the fetus. However it is not certain whether Toxoplasma infection can cause recurrent abortion. The aim of this study was to determine the relationship between Toxoplasma infection and abortion via detection of anti-Toxoplasma gondii antibodies in sera of women with obstetrical problems and compare the results with control group consisting of women with history of normal delivery. Sera from 130 women with abortion and sera of 130 women with normal delivery were tested for IgG and IgM anti-Toxoplasma gondii antibodies by ELISA method. The present study revealed 24.6% of the samples with abortion and 21.5% of the samples with normal delivery were positive for IgG antibodies. However, statistical analysis indicated no significant differences (P>0.05). In addition, IgM antibody was detected in one woman who had aborted but not in women with normal childbirth. This study showed no significant difference between the case and control groups in IgG anti-Toxoplasma antibody but detected one sample with IgM antibodies in woman with abortion during the first trimester of pregnancy. In order to determine the relationship between Toxoplasma infection and abortion, anti-Toxoplasma IgG avidity and PCR to discriminate between recent and prior infections are recommended

    The effect of evening primrose oil on fatigue and quality of life in patients with multiple sclerosis

    Get PDF
    Abstract Background Multiple sclerosis (MS) is a chronic progressive and inflammatory disease of the central nervous system that is characterized by demyelination in the central nervous system. In regard to the prevalence of diseases and enormous costs imposed on society and the health system, finding a way to stop the progression of the disease using drugs with fewer side effects seems a serious sanitation issue to the health of the international community. This study aimed to evaluate the effect of evening primrose oil (EPO) on fatigue and quality of life in patients with MS. Materials and methods In this double-blind randomized clinical trial, 52 patients with MS were chosen and categorized into 2 groups which received 2 doses of EPO and placebo. In addition, the quality of life and fatigue scale in these patients were investigated before the treatment and again 3 months after therapy. The findings were then compared between the 2 groups. Result EPO consumption significantly increased cognitive function, vitality, and overall life satisfaction and also reduced pain and fatigue compared to placebo (P<0.05). Conclusion Our findings indicated that EPO consumption had no impact on the quality of life in general; however, it had a significant effect on several important aspects of life quality such as the increase of cognitive function, vitality, and overall life satisfaction. It also reduced the pain and fatigue in comparison to the placebo consumption. Herbal medicines are brittle and have fewer side effects than chemical drugs. With use of this plant, reduced fatigue and improved quality of life were observed in MS patients. But the drug did not prevent the progression of the disease. Keywords: cognitive function, vitality, overall life satisfaction, pain, fatigu

    Inhibitory effect of HIV-specific neutralizing IgA on mucosal transmission of HIV in humanized mice

    Get PDF
    HIV-1 infections are generally initiated at mucosal sites. Thus, IgA antibody, which plays pivotal roles in mucosal immunity, might efficiently prevent HIV infection. However, mounting a highly effective HIV-specific mucosal IgA response by conventional immunization has been challenging and the potency of HIV-specific IgA against infection needs to be addressed in vivo. Here we show that the polymeric IgA form of anti-HIV antibody inhibits HIV mucosal transmission more effectively than the monomeric IgA or IgG1 form in a comparable range of concentrations in humanized mice. To deliver anti-HIV IgA in a continual manner, we devised a hematopoietic stem/progenitor cell (HSPC)–based genetic approach using an IgA gene. We transplanted human HSPCs transduced with a lentiviral construct encoding a class-switched anti-HIV IgA (b12-IgA) into the humanized bone marrow-liver-thymus (BLT) mice. The transgene was expressed specifically in B cells and plasma cells in lymphoid organs and mucosal sites. After vaginal HIV-1 challenge, mucosal CD4^+ T cells in the b12-IgA–producing mice were protected from virus-mediated depletion. Similar results were also obtained in a second humanized model, “human immune system mice.” Our study demonstrates the potential of anti-HIV IgA in immunoprophylaxis in vivo, emphasizing the importance of the mucosal IgA response in defense against HIV/AIDS
    • …
    corecore