120 research outputs found

    Cognitive functions in neurofibromatosis type 1 patients and unaffected siblings

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    Attention, learning, and perceptual problems have been reported at various degrees and rates in neurofibromatosis type 1 (NF1). We aimed to define the cognitive profiles frequently associated with NF1. Children and adolescents with NF1 (n=58) were tested using Wechsler Intelligence Scales for Children-Revised (WISC-R), Judgment of Line Orientation, and Bender Visual-Motor Gestalt tests. Comparison groups were unaffected siblings of NF1 patients (n=20), children with attention deficit and hyperactivity disorder (ADHD, n=40), and normal children (n=40). No difference was found between familial or sporadic NF1 cases. Seventeen/58 (29%) of NF1 cases had a full scale IQ 80 (n=27) scored lower in WISC-R subtests measuring visual perception when compared to a healthy control group of similar intelligence, and lower in arithmetic but better in Bender-Gestalt and Judgment of Line Orientation tests when compared to an ADHD group of similar intelligence. These results indicate a high prevalence of mental retardation in a clinical NF1 series. NF1 patients who have normal intelligence may have impaired visual perception, but their visual perceptual problems are less than in ADHD. The tendency of unaffected siblings of NF1 patients to have mildly but consistently low test scores compared to healthy controls needs to be studied further for underlying genetic or environmental factors

    Neurophysiological evidence for rapid processing of verbal and gestural information in understanding communicative actions

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    During everyday social interaction, gestures are a fundamental part of human communication. The communicative pragmatic role of hand gestures and their interaction with spoken language has been documented at the earliest stage of language development, in which two types of indexical gestures are most prominent: the pointing gesture for directing attention to objects and the give-me gesture for making requests. Here we study, in adult human participants, the neurophysiological signatures of gestural-linguistic acts of communicating the pragmatic intentions of naming and requesting by simultaneously presenting written words and gestures. Already at ~150 ms, brain responses diverged between naming and request actions expressed by word-gesture combination, whereas the same gestures presented in isolation elicited their earliest neurophysiological dissociations significantly later (at ~210 ms). There was an early enhancement of request-evoked brain activity as compared with naming, which was due to sources in the frontocentral cortex, consistent with access to action knowledge in request understanding. In addition, an enhanced N400-like response indicated late semantic integration of gesture-language interaction. The present study demonstrates that word-gesture combinations used to express communicative pragmatic intentions speed up the brain correlates of comprehension processes – compared with gesture-only understanding – thereby calling into question current serial linguistic models viewing pragmatic function decoding at the end of a language comprehension cascade. Instead, information about the social-interactive role of communicative acts is processed instantaneously

    PRISMA for abstracts: best practice for reporting abstracts of systematic reviews in Endodontology

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    An abstract is a brief overview of a scientific, clinical or review manuscript as well as a stand‐alone summary of a conference abstract. Scientists, clinician–scientists and clinicians rely on the summary information provided in the abstracts of systematic reviews to assist in subsequent clinical decision‐making. The Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) for Abstracts checklist was developed to improve the quality, accuracy and completeness of abstracts associated with systematic reviews and meta‐analyses. The PRISMA for Abstracts checklist provides a framework for authors to follow, which helps them provide in the abstract the key information from the systematic review that is required by stakeholders. The PRISMA for Abstracts checklist contains 12 items (title, objectives, eligibility criteria, information sources, risk of bias, included studies, synthesis of results, description of the effect, strength and limitations, interpretation, funding and systematic review registration) under six sections (title, background, methods, results, discussion, other). The current article highlights the relevance and importance of the items in the PRISMA for Abstracts checklist to the specialty of Endodontology, while offering explanations and specific examples to assist authors when writing abstracts for systematic reviews when reported in manuscripts or submitted to conferences. Strict adherence to the PRISMA for Abstracts checklist by authors, reviewers and journal editors will result in the consistent publication of high‐quality abstracts within Endodontology

    Validation of an automated assay for the measurement of cupric reducing antioxidant capacity in serum of dogs

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    BACKGROUND: The objective of the present study was to optimize and validate an automated method to assess the total antioxidant capacity (TAC) in serum of dogs using the cupric reducing antioxidant capacity (CUPRAC) methodology (TAC(c)) with bathocuproinedisulfonic acid disodium salt as chelating agent, evaluating also possible variations due to the use of two different automated analyzers. The method is based on the reduction of Cu(2+) into Cu(1+) by the action of the non-enzymatic antioxidants that are present in the sample. RESULTS: Imprecision was low in both apparatus utilized, and the results were linear across serial Trolox and canine serum samples dilutions. Lipids did not interfere with the assay; however, hemolysis increased the TAC(c) concentrations. When TAC(c) concentrations were determined in ten healthy (control) dogs and in twelve dogs with inflammatory bowel disease (IBD), dogs with IBD had lower TAC(c) concentrations when compared with the healthy dogs. CONCLUSIONS: The method validated in this paper is precise, simple, and fast and can be easily adapted to automated analyzers

    Effect of autoclave sterilisation and heat activated sodium hypochlorite irrigation on the performance of nickel-titanium rotary files against cyclic fatigue

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    The present study aims to assess the impact of heat-activated sodium hypochlorite (NaOCl) and/or autoclave sterilisation on the cyclic fatigue resistance (CFR) of heat-treated nickel-titanium rotary files used in root canal treatment. The CFR of One Curve (OC) files was evaluated under the following conditions: as received (Group 1; control), immersion in NaOCl at 23 ± 1ºC (Group 2), immersion in NaOCl at 60 ± 1ºC (Group 3), autoclave sterilisation at 135 1ºC (Group 4), combined treatment of autoclave sterilisation and immersion in NaOCl at 23 ± 1ºC (Group 5), and combined treatment of autoclave sterilisation and immersion in NaOCl at 60 ± 1ºC (Group 6). A simulated root canal in a zirconia block was utilised to test the performance of the files. All the types of treatments resulted in significant reductions in fracture resistance of the OC files. Immersion of the files in NaOCl at 23ºC revealed the smallest reduction, while combined treatment of autoclaving and immersion in NaOCl at 60ºC caused the greatest reduction. Autoclave sterilisation or exposure of OC files to 2.5% NaOCl adversely affect the cyclic fatigue life and increasing solution temperature or combined treatment caused additionally significant reduction in CFR

    Condyle position in Class II Division 1 malocclusion patients: Correlation between MPI records and CBCT images

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    Background: This study was designed to test the hypothesis that condyle position, as measured by cone beam computed tomography (CBCT), is correlated with the amount and direction of centric slide, determined using a mandibular position indicator (MPI). Methods: In this descriptive study, 40 Class II Division 1 patients with no signs or symptoms of temporomandibular joint disorder were evaluated. Power centric registration and CBCT imaging were performed for each patient. Mandibular position registrations were performed using a mandibular position indicator (MPI). The concentric positions of the condyles were assessed using CBCT imaging. Results: Based on the MPI findings, 57.5% of the patients studied showed a centric relation-centric occlusion discrepancy of ?2 mm in at least one direction at the level of the condyles. Eighty-two percent of the condylar distractions were found to be in the vertical inferior direction. Based on CBCT image tracing, nearly 87.5% of the condyle positions were found to be nonconcentric for the right and left sides. Significant anterior positioning of the condyles was revealed. No relationship was found between the MPI findings and the CBCT measurements. Conclusions: The hypothesis was rejected. The concentricity of the condyle in the mandibular fossa as determined using CBCT measurements cannot be used to predict the centric relation-centric occlusion changes at the level of the condyles. © 2013 World Federation of Orthodontists

    Corrosion behaviour and electrical conductivity of reinforced TiAl₃ and B₄C hybrid aluminium composites

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    In this study, corrosion and electric conductivity of aluminum hybrid composites (in situ TiAl₃ and ex situ B₄C) produced by powder metallurgy are investigated. Hybrid (in situ and ex situ) aluminum composite powders are produced by adding different amounts of titanium and B₄C into AA7075 alloy powders. After the hybrid composite powders are cold pressed (600 MPa), they are sintered in atmosphere controlled furnace at 580°C for 4 h. As a result of this study, it was observed that increase of B₄C%(Ti constant) decreases density and increase of Ti%(B₄C constant) increases the density of composites. It was determined that corrosion resistances (R_{p}) of hybrid composites decreased due to interface surfaces formed between the reinforcement phase and the matrix

    Electrical Conductivity and Corrosion Performances of In Situ and Ex Situ AA7075 Aluminum Composites

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    The present study investigates corrosion behaviors and electric conductivity of AA7075 in situ (TiAl₃) and ex situ (B₄C) composites produced by powder metallurgy method. In production of in situ composites, various amounts of Ti (2, 4 and 6%) are added to AA7075 and for production of ex situ composites, B₄C (3, 6, and 9%) are added. Prepared in situ and ex situ composite powders were pre-shaped at 600 MPa pressure with cold pressing. Pre-shaped samples were sintered in the atmosphere-controlled furnace at 580°C for 4 h. Corrosion test of produced composites was conducted in 0.1 M H₂SO₄ solution. As a result of these analyses, corrosion examinations on in situ manufactured composites revealed that anode and cathode currents are close to each other and those composites do not exhibit different corrosion behaviors. Corrosion rate of B₄C added ex situ composites increases by B₄C rate (due to increase of density of current)

    Investigation of Wear Behavior of Precipitation-Strengthened Nickel-Copper Based K-500 Alloy Produced by Powder Metallurgy

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    The present study investigates the effects of the ageing parameters of the precipitation-strengthened nickel-copper based K-500 alloy produced by powder metallurgy on the wear behavior of the alloy. After the cold pressing the prepared alloy powders under 600 MPa pressure, the samples were sintered under vacuum (10¯⁶ mbar) at 1150°C for 2 h and then cooled in the furnace. Produced K-500 alloy samples were taken into solution at 980°C for 1 h and quenched. Ageing process was carried out at 480°C for four different time periods (6, 8, 10, and 12 h). Aged samples were examined transmission electron microscope (TEM + EDS), X-ray diffraction (XRD), hardness and density measurements. The wear tests were carried out at 1 ms¯¹ constant sliding speed, under 40 N load and for five different sliding distances (400-2000 m). The results showed that there is γ' Ni₃(Al, Ti) inter-metallic phase coexisting with Al0.9Ni4.22Al_{0.9}Ni_{4.22}, AlNi₃ and NiO phases. According to the hardness measurements, the highest hardness values were obtained with samples aged for 8 h. In wear tests with 2000 m sliding distance, the lowest weight loss was observed for the samples aged for 8 h
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