2,206 research outputs found

    Pemphigoid diseases affecting the skin

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    Pemphigoid diseases are a heterogeneous group of subepidermal autoimmune blistering diseases (sAIBD) that are characterized by autoantibodies against different structural proteins of hemidesmosomes in the epidermal basement membrane zone (EBMZ). The group of pemphigoid diseases affecting the skin include various subtypes, such as bullous pemphigoid (BP), nonbullous pemphigoid (NBP), Brunsting-Perry cicatricial pemphigoid, lichen planus pemphigoides (LPP), pemphigoid gestationis (PG), and anti-p200 pemphigoid. Classification of sAIBD subtypes is mainly based on target antigens and/or clinical manifestations. Pathogenesis of pemphigoid diseases is mediated by predominantly IgG autoantibodies against different structural proteins in the EBMZ. Diagnosis is based on a combination of clinical features, an n-serrated linear pattern of immunodepositions along the EBMZ in direct immunofluorescence microscopy and immunoserology. BP is the most common subtype and most frequently affects elderly, the incidence of BP increased substantially in the past decades. The clinical manifestations of pemphigoid diseases are heterogeneous and represent a clinical spectrum. The typical presentation of BP is a severe pruritus with a predominantly cutaneous lesions consisting of tense blisters or vesicles, erythema and urticarial plaques. In NBP blistering is absent, while the pruritus is severe, and erythematous papules, plaques and excoriations may mimick other inflammatory dermatoses. Recommended therapies consists of whole-body application of superpotent topical corticosteroids, or systemic treatment with immunosuppressive or -modulating drugs.</p

    The Effect of Waxed and Unwaxed Dental Floss on Gingival Health: Part I. Plaque Removal and Gingival Response

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141099/1/jper0393.pd

    Tunnelling dominates the reactions of hydrogen atoms with unsaturated alcohols and aldehydes in the dense medium

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    Hydrogen addition and abstraction reactions play an important role as surface reactions in the buildup of complex organic molecules in the dense interstellar medium. Addition reactions allow unsaturated bonds to be fully hydrogenated, while abstraction reactions recreate radicals that may undergo radical-radical recombination reactions. Previous experimental work has indicated that double and triple C--C bonds are easily hydrogenated, but aldehyde -C=O bonds are not. Here, we investigate a total of 29 reactions of the hydrogen atom with propynal, propargyl alcohol, propenal, allyl alcohol, and propanal by means of quantum chemical methods to quantify the reaction rate constants involved. First of all, our results are in good agreement with and can explain the observed experimental findings. The hydrogen addition to the aldehyde group, either on the C or O side, is indeed slow for all molecules considered. Abstraction of the H atom of the aldehyde group, on the other hand, is among the faster reactions. Furthermore, hydrogen addition to C--C double bonds is generally faster than to triple bonds. In both cases, addition on the terminal carbon atom that is not connected to other functional groups is easiest. Finally, we wish to stress that it is not possible to predict rate constants based solely on the type of reaction: the specific functional groups attached to a backbone play a crucial role and can lead to a spread of several orders of magnitude in the rate constant.Comment: Accepted for publication in A&

    The Effect of Waxed and Unwaxed Dental Floss on Gingival Health: Part II. Crevicular Fluid Flow and Gingival Bleeding

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141127/1/jper0397.pd

    Silver Complexation by Metallacryptates

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    We report the first complete characterization of metallycryptates encapsulating Ag(i) cations: carboxylato ligands derived from l-proline and l-alanine chelate and bridge six Cu(ii) centres arranged in a slightly distorted octahedral fashion

    Self-Awareness After Brain Injury:Relation with Emotion Recognition and Effects of Treatment

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    Item does not contain fulltextSelf-awareness is often impaired after acquired brain injury (ABI) and this hampers rehabilitation, in general: unrealistic reports by patients about their functioning and poor motivation and compliance with treatment. We evaluated a self-awareness treatment that was part of a treatment protocol on executive dysfunction (Spikman, Boelen, Lamberts, Brouwer, & Fasotti, 2010). A total of 63 patients were included, aged 17-70, suffering non-progressive ABI, and minimum time post-onset of 3 months. Self-awareness was measured by comparing the patient's Dysexecutive Questionnaire (Wilson, Alderman, Burgess, Emslie, & Evans, 1996) score with that of an independent other. As emotion recognition is associated with self-awareness and influences the effect of rehabilitation treatment, we assessed this function using the Facial Expressions of Emotion-Stimuli and Tests (Young, Perrett, Calder, Sprengelmeyer, & Ekman, 2002). Results showed that patients in the experimental treatment group (n = 29) had better self-awareness after training than control patients (n = 34). Moreover, our results confirmed that the level of self-awareness before treatment was related to emotion recognition. Hence, self-awareness can improve after neuropsychological treatment fostering self-monitoring. Since neuropsychological treatment involves social learning, impairments in social cognition should be taken into account before starting and during treatment.8 p

    Relevance of the H_2 + O reaction pathway for the surface formation of interstellar water. Combined experimental and modeling study

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    The formation of interstellar water is commonly accepted to occur on the surfaces of icy dust grains in dark molecular clouds at low temperatures (10–20 K), involving hydrogenation reactions of oxygen allotropes. As a result of the large abundances of molecular hydrogen and atomic oxygen in these regions, the reaction H_2 + O has been proposed to contribute significantly to the formation of water as well. However, gas-phase experiments and calculations, as well as solid-phase experimental work contradict this hypothesis. Here, we use precisely executed temperature-programmed desorption (TPD) experiments in an ultra-high vacuum setup combined with kinetic Monte Carlo simulations to establish an upper limit of the water production starting from H_2 and O. These reactants were brought together in a matrix of CO_2 in a series of (control) experiments at different temperatures and with different isotopological compositions. The water detected with the quadrupole mass spectrometer upon TPD was found to originate mainly from contamination in the chamber itself. However, if water is produced in small quantities on the surface through H_2 + O, this can only be explained by a combined classical and tunneled reaction mechanism. An absolutely conservative upper limit for the reaction rate was derived with a microscopic kinetic Monte Carlo model that converts the upper limit into the highest possible reaction rate. Incorporating this rate into simulation runs for astrochemically relevant parameters shows that the upper limit to the contribution of the reaction H_2 + O in OH, and hence water formation, is 11% in dense interstellar clouds. Our combined experimental and theoretical results indicate, however, that this contribution is most likely much lower

    Increased serum strontium levels in dialysis patients: An epidemiological survey

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    Increased serum strontium levels in dialysis patients: An epidemiological survey.BackgroundWe previously reported on increased bone strontium levels in dialysis patients with osteomalacia versus those presenting other types of renal osteodystrophy. A causal role of strontium in the development of osteomalacia was established in a chronic renal failure rat model.MethodsTo further elucidate the latter issue and to find out whether dialysis patients from particular centers/countries are at an increased risk for strontium accumulation, a worldwide multicenter study was established. In total, 834 patients from 34 dialysis centers in 23 countries were included. In each of the patients, a serum sample was taken for strontium determination, and water and dialysate samples were taken at the various steps of the water purification process. For each patient clinical data and for each center dialysis modalities were recorded.ResultsStrontium levels in serum of dialysis patients showed major differences between the various centers, ranging from mean values of 25 ± 8 μg/liter in the center with the lowest level up to 466 ± 90 μg/liter in the center with the highest concentration. It is of interest that these high levels were mainly found in developing countries. Furthermore, our data point toward a role of the final dialysate in the accumulation of the element, as indicated by the strong correlation (r = 0.74, P < 0.001) between mean serum and dialysate strontium levels. As the high tap water concentration of strontium was adequately reduced during the water purification process, contamination of the final dialysis fluid occurred by the addition of concentrates contaminated with strontium. Besides the dialysate, other factors, such as duration of dialysis, vitamin D supplements, or types of phosphate binders, played a less important role in the accumulation of the element.ConclusionsData of this multicenter study indicate patients of particular dialysis centers to be at an increased risk for strontium accumulation, the clinical consequence of which is under current investigation
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