9,364 research outputs found

    The Effects of Surface Roughening Techniques on Surface and Electrochemical Properties of Ti Implants

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    This chapter deals with the effect of commonly used surface roughening techniques for rapid osseointegration on surface and electrochemical properties of dental implants. Dental implants prepared by smooth machining (MAC), double acid etching (DAE), sandblasting and acid etching (SLA), Ti plasma spray (TPS) and anodization (ANO) were included, and their electrochemical properties were compared to untreated commercially pure titanium (cpTi). The treated surfaces demonstrated great differences in surface roughness, morphology, elemental composition and oxide type. Open circuit potential (OCP) and anodic scan potentiodynamic curves showed that electrochemical properties of treated surfaces are inferior to untreated cpTi in an original Ringer’s solution and a Ringer’s solution enriched with NaF except from the case of ANO where the electrochemical properties were enhanced. Galvanic action between dental implants and prosthetic superstructures and more importantly between the treated root and polished collar of dental implants is also discussed

    Nutritional and health status of adult Syrian refugees in the early years of asylum in Germany: a cross-sectional pilot study

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    Background: Migration is usually accompanied by changes in the social, cultural, and religious environment, socioeconomic status, and housing conditions, all of which affect nutritional health. In a cross-sectional study, we assessed the dietary intake as well as nutritional and health situation in a population of Syrian refugees who have resided in Germany for at least six months up to four years since 2015. The primary aim of this pilot study was to evaluate the nutritional and health status in comparison to reference values. Methods: Between December 2018 and March 2020, 114 adult Syrian refugees were included in the study. The subjects filled out questionnaires on sociodemographic variables, exercise, and nutrition behavior (three-day nutrition record). After a fasting blood draw, the subjects were examined for anthropometric parameters (height, weight, body mass index, waist circumference, waist-hip ratio, and body composition via a bioelectrical impedance analyzer). Various blood markers including iron status, hematological parameters, Vitamin D status, lipid metabolism, glucose metabolism, and total homocysteine (tHcy) were measured. Results: About half of the participants (71 male, 43 female) had lived in Germany for less than three years. Over 60% of men and 30% of women were overweight (BMI 25–30 kg/m2) or obese (BMI > 30 kg/m2), while 79% of men and 74% of women observed an elevated body fat mass. The evaluation of the three-day nutrition records revealed an unfavorable supply situation for numerous critical nutrients. More than half of the women (53.5%) had depleted iron stores (serum ferritin  10 nmol/l. Fasting insulin levels and the HOMA-IR index indicate a risk for insulin resistance. Hyperlipidemia was prevalent, especially in males with 24% showing hypertriglyceridemia (> 150 mg/dl) and LDL-hypercholesterolemia (> 130 mg/dl). Conclusions: The nutritional and health status of the cohort of Syrian refugees in Germany examined in this study is unsatisfactory, and many of the investigated refugees are at risk for developing cardiovascular disease and type 2 diabetes mellitus. Further studies are required to investigate the nutritional and health situation of refugees. This is obligatory to find ways to avoid malnutrition with all its associated health, sociodemographic, and economic consequences

    Environmental associations of cownose ray (Rhinoptera bonasus) seasonal presence along the U.S. Atlantic Coast

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    Identifying the mechanistic drivers of migration can be crucial in shaping conservation and management policies. The cownose ray (Rhinoptera bonasus) is a relatively poorly understood elasmobranch species that occurs along the U.S. Atlantic coast and undergoes large-scale seasonal migrations. To better understand the drivers and timing of cownose ray seasonal migration in order to inform potential management measures, we analyzed telemetry detections of 51 mature cownose rays (38 female, 13 male) tagged with acoustic transmitters in the Maryland and Virginia portions of Chesapeake Bay. Detections within their summer habitat in Chesapeake Bay and winter habitat in the vicinity of Cape Canaveral, Florida, were matched with publicly available sea surface temperature (SST) data recorded by data buoys near the areas of tag detections and with local photoperiod and day of year. These variables were used in boosted regression tree models of ray presence (all rays combined, females only, and males only) in each seasonal habitat. Models were developed for presence during the entire summer and winter season, and for the time periods of arrival and departure from both summer and winter habitats. Seasonal presence in both summer and winter habitats was associated with distinct temperature, photoperiod, and date ranges, with temperature as the most influential variable in seasonal models. In models of arrival and departure periods, southward migration (departure from Chesapeake Bay and arrival off Cape Canaveral) was strongly associated with SST for all rays and arrival in the Chesapeake Bay region after northward migration was most strongly associated with day of year. The most influential variable during the period of northward departure from Cape Canaveral differed between males (day of year) and females (SST). This suggests that mature female northward migration may be driven by temperature while male northward migration may be driven by endogenous cues. These findings provide detailed information on the timing of cownose ray arrival at, presence in, and departure from seasonal habitats and provide potential justification for including the species in cross-taxa comparative studies on migratory behavior

    Using a Fiber-Optic Probe for the Measurement of Volumetric Expansion of Liquids

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    A Fiber-Optic Probe is Developed for the Fast, In-Situ Measurement of Volumetric Expansion of Multiphase and Multicomponent Systems. an Experiment with the Binary Mixtures of CO2-Toluene and CO2-Ethanol Was Conducted to Demonstrate the Usefulness of the Fiber-Optic Probe in Accurately Tracking the Isothermal Volumetric Expansion as a Function of Pressure. in the 1-L Autoclave that Has Been Used, the Probe Was Shown to Detect the Liquid Level Height within a Precision of 0.35% of the Total Height of the Vessel. the Results for the Volumetric Expansion of Toluene and Ethanol with CO2 Correlate Well with Those Found in the Literature. the Probe itself Can Be Used Up to Pressures of 140 Barg and Temperatures of 120°C. © 2007 American Chemical Society

    The role of PKC in CXCL8 and CXCL10 directed prostate, breast and leukemic cancer cell migration

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    Migration of tumour cells is a fundamental process for the formation and progression of metastasis in malignant diseases. Chemokines binding to their cognate receptors induce the migration of cancer cells, however, the molecular signalling pathways involved in this process are not fully understood. Protein kinase C (PKC) has been shown to regulate cell migration, adhesion and proliferation. In order to identify a connection between PKC and tumour progression in breast, prostate and leukaemia cells, the effect of PKC on CXCL8 or CXCL10-mediated cell migration and morphology was analysed. We tested the speed of the migrating cells, morphology, and chemotaxis incubated with different PKC isoforms inhibitors- GF109203X, staurosporine and PKCζ pseudosubstrate inhibitor (PKCζi). We found that the migration of CXCL8-driven PC3 and MDA-MB231 cells in the presence of conventional, novel or atypical PKCs was not affected, but atypical PKCζ is crucial for THP-1 chemotaxis. The speed of CXCL10-activated PC3 and MDA-MB231 cells was significantly reduced in the presence of conventional, novel and atypical PKCζ. THP-1 chemotaxis was again affected by atypical PKCζi. On the other hand, cell area, circularity or aspect ratio were affected by staurosporine in CXCL8 or CXCL10-activated cells, demonstrating a role of PKCα in the rearrangement of the cytoskeleton regardless of the effect on the migration. Consequently, this allows the speculation that different PKC isoforms induce different outcomes in migration and actin cytoskeleton based on the chemokine receptor and/or the cell type

    Etiology, 3-Month Functional Outcome and Recurrent Events in Non-Traumatic Intracerebral Hemorrhage

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    BACKGROUND AND PURPOSE Knowledge about different etiologies of non-traumatic intracerebral hemorrhage (ICH) and their outcomes is scarce. METHODS We assessed prevalence of pre-specified ICH etiologies and their association with outcomes in consecutive ICH patients enrolled in the prospective Swiss Stroke Registry (2014 to 2019). RESULTS We included 2,650 patients (mean±standard deviation age 72±14 years, 46.5% female, median National Institutes of Health Stroke Scale 8 [interquartile range, 3 to 15]). Etiology was as follows: hypertension, 1,238 (46.7%); unknown, 566 (21.4%); antithrombotic therapy, 227 (8.6%); cerebral amyloid angiopathy (CAA), 217 (8.2%); macrovascular cause, 128 (4.8%); other determined etiology, 274 patients (10.3%). At 3 months, 880 patients (33.2%) were functionally independent and 664 had died (25.1%). ICH due to hypertension had a higher odds of functional independence (adjusted odds ratio [aOR], 1.33; 95% confidence interval [CI], 1.00 to 1.77; P=0.05) and lower mortality (aOR, 0.64; 95% CI, 0.47 to 0.86; P=0.003). ICH due to antithrombotic therapy had higher mortality (aOR, 1.62; 95% CI, 1.01 to 2.61; P=0.045). Within 3 months, 4.2% of patients had cerebrovascular events. The rate of ischemic stroke was higher than that of recurrent ICH in all etiologies but CAA and unknown etiology. CAA had high odds of recurrent ICH (aOR, 3.38; 95% CI, 1.48 to 7.69; P=0.004) while the odds was lower in ICH due to hypertension (aOR, 0.42; 95% CI, 0.19 to 0.93; P=0.031). CONCLUSIONS Although hypertension is the leading etiology of ICH, other etiologies are frequent. One-third of ICH patients are functionally independent at 3 months. Except for patients with presumed CAA, the risk of ischemic stroke within 3 months of ICH was higher than the risk of recurrent hemorrhage

    Elemental, Morphological, and Corrosion Characterization of Different Surface States of Co-Cr Alloy for Prosthodontic Applications

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    In this study, four different groups were prepared in a cast model of an arch that received four implants made with a Co-Cr dental alloy. The surface of each group was prepared by four different surface treatments, including sandblasting with Al2O3 grains (SB), conventional finishing with dental burs (CF), milling with a CAD/CAM device (MIL), and electrodischarge machining (EDM). The characterization of the roughness parameters, morphology, elemental composition, and electrochemical properties of a dental Co-Cr alloy in different surface states exposed to an oral environment were reported. The electrochemical properties were tested with open-circuit potential (OCP) and anodic scan in Ringer’s solutions. The results of roughness parameters, elemental composition, OCP, corrosion potential and pitting potential were statistically analyzed by one-way ANOVA and the Tukey-Kramer multiple- comparison test at 95% confidence level. The roughness parameters classified the surfaces from smoothest to roughest according to the following order; CF, MIL, EDM, and SB. The CF group has the best corrosion resistance followed by the EDM, MIL, and SB groups

    Electromagnetic transitions of the helium atom in superstrong magnetic fields

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    We investigate the electromagnetic transition probabilities for the helium atom embedded in a superstrong magnetic field taking into account the finite nuclear mass. We address the regime \gamma=100-10000 a.u. studying several excited states for each symmetry, i.e. for the magnetic quantum numbers 0,-1,-2,-3, positive and negative z parity and singlet and triplet symmetry. The oscillator strengths as a function of the magnetic field, and in particular the influence of the finite nuclear mass on the oscillator strengths are shown and analyzed.Comment: 10 pages, 8 figure

    Energy levels of light atoms in strong magnetic fields

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    In this review article we provide an overview of the field of atomic structure of light atoms in strong magnetic fields. There is a very rich history of this field which dates back to the very birth of quantum mechanics. At various points in the past significant discoveries in science and technology have repeatedly served to rejuvenate interest in atomic structure in strong fields, broadly speaking, resulting in three eras in the development of this field; the historical, the classical and the modern eras. The motivations for studying atomic structure have also changed significantly as time progressed. The review presents a chronological summary of the major advances that occurred during these eras and discusses new insights and impetus gained. The review is concluded with a description of the latest findings and the future prospects for one of the most remarkably cutting-edge fields of research in science today.Comment: 37 pages, 16 figures, 1 tabl
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