120 research outputs found

    Affordances of Augmented Reality Systems for Co-Located Collaboration

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    This paper aims to identify relevant affordances towards an augmented reality system for organizational practices of co-located collaboration. As augmented reality is a means to visualize and author information, such an artifact could enable intuitive sharing of information. It can be shown that single aspects are reflected in literature, missing so far is a comprehensive description of relevant affordances for such an artifact. The concept of affordances is increasingly used in information research, as it enables to define design principle based on the action goals of the user. Addressing the lack of clear formulation guidelines of affordances, a proposal is presented of how affordances can be formulated to reduce uncertainty and ambiguity. This paper makes two major contributions: (1) it introduces how augmented reality systems can contribute to organizational practices of co-located collaboration and (2) illustrates how affordances can be utilized to derive requirements for such systems from interviews

    Quality of life and surgical outcome of ABBA versus EndoCATS endoscopic thyroid surgery: a single center experience

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    BACKGROUND Thyroid surgery is often performed, especially in young female patients. As patient satisfaction become more and more important, different extra-cervical \textquotedblremote\textquotedbl approaches have evolved to avoid visible scars in the neck for better cosmetic outcome. The most common remote approaches are the transaxillary and retroauricular. Aim of this work is to compare Endoscopic Cephalic Access Thyroid Surgery (EndoCATS) and axillo-bilateral-breast approach (ABBA) to standard open procedures regarding perioperative outcome and in addition to control cohorts regarding quality of life (QoL) and patient satisfaction. METHODS In a single center, 59 EndoCATS und 52 ABBA procedures were included out of a 2 years period and compared to 225 open procedures using propensity-score matching. For the endoscopic procedures, cosmetic outcome, patient satisfaction and QoL (SF-12 questionnaire) were examined in prospective follow-up. For QoL a German standard cohort and non-surgically patients with thyroid disease were used as controls. RESULT The overall perioperative outcome was similar for all endoscopic compared to open thyroid surgeries. Surgical time was longer for endoscopic procedures. There were no cases of permanent hypoparathyroidism and no significant differences regarding temporary or permanent recurrent laryngeal nerve (RLN) palsies between open and ABBA or EndoCATS procedures (χ2; p = 0.893 and 0.840). For ABBA and EndoCATS, 89.6% and 94.2% of patients were satisfied with the surgical procedure. Regarding QoL, there was an overall significant difference in distribution for physical, but not for mental health between groups (p < 0.001 and 0.658). Both endoscopic groups performed slightly worse regarding physical health, but without significant difference between the individual groups in post hoc multiple comparison. CONCLUSION Endoscopic thyroid surgery is safe with comparable perioperative outcome in experienced high-volume centers. Patient satisfaction and cosmetic results are excellent; QoL is impaired in surgical patients, as they perform slightly worse compared to German standard cohort and non-surgical patients

    Microstructure-Based Lifetime Assessment of Austenitic Steel AISI 347 in View of Fatigue, Environmental Conditions and NDT

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    The assessment of metallic materials used in power plants’ piping represents a big challenge due to the thermal transients and the environmental conditions to which they are exposed. At present, a lack of information related to degradation mechanisms in structures and materials is covered by safety factors in its design, and in some cases, the replacement of components is prescribed after a determined period of time without knowledge of the true degree of degradation. In the collaborative project “Microstructure-based assessment of maximum service life of nuclear materials and components exposed to corrosion and fatigue (MibaLeb)”, a methodology for the assessment of materials’ degradation is being developed, which combines the use of NDT techniques for materials characterization, an optimized fatigue lifetime analysis using short time evaluation procedures (STEPs) and numerical simulations. In this investigation, the AISI 347 (X6CrNiNb18-10) is being analyzed at different conditions in order to validate the methodology. Besides microstructural analysis, tensile and fatigue tests, all to characterize the material, a pressurized hot water pipe exposed to a series of flow conditions will be evaluated in terms of full-scale testing as well as prognostic evaluation, where the latter will be based on the materials’ data generated, which should prognose changes in the material’s condition, specifically in a pre-cracked stage. This paper provides an overview of the program, while the more material’s related aspects are presented in the subsequent paper

    A TNF-α Promoter Polymorphism Is Associated with Juvenile Onset Psoriasis and Psoriatic Arthritis

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    Tumor necrosis factor-α is considered to be one of the important mediators in the pathogenesis of psoriasis. A strong association of juvenile onset psoriasis with the major histocompatibility complex encoded HLA-Cw6 antigen has been reported but it is unclear whether Cw6 itself or a closely linked gene is involved in the pathogenesis. This study has focused on the association of promoter polymorphisms of the major histocompatibility complex encoded tumor necrosis factor-α gene with psoriasis and psoriatic arthritis. Tumor necrosis factor-α promoter polymorphisms were sought by sequence-specific oligonucleotide hybridization and by direct sequencing in Caucasian patients with juvenile onset psoriasis and with psoriatic arthritis and in healthy controls. A mutation at position −238 of the tumor necrosis factor-α promoter was present in 23 of 60 patients (38%; p < 0.0001; Pcorr < 0.008) with juvenile onset psoriasis and in 20 of 62 patients (32%; p < 0.0003; Pcorr < 0.03) with psoriatic arthritis, compared with seven of 99 (7%) Caucasian controls. There was a marked increase of homozygotes for this mutation in the psoriasis group. Another mutation at position −308 was found in similar proportions of patients and controls. Our study shows a strong association of the tumor necrosis factor-α promoter polymorphism at position −238 with psoriasis and psoriatic arthritis. Our findings suggest that this promoter polymorphism itself or a gene in linkage disequilibrium with tumor necrosis factor-α predispose to the development of psoriasis

    A Short-Time Approach for Fatigue Life Evaluation of AISI 347 Steel for Nuclear Power Energy Applications

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    AISI 347 austenitic steel is, as an example, used in nuclear energy piping systems. Piping filled with superheated steam or cooled water is particularly exposed to high stresses, whereupon local material properties in the pipes can change significantly, especially in the case of additional corrosive influences, leading to aging of the material. In the absence of appropriate information, such local material property variations are currently covered rather blanketly by safety factors set during the design of those components. An increase in qualified information could improve the assessment of the condition of such aged components. As part of the collaborative project “Microstructure-based assessment of the maximum service life of core materials and components subjected to corrosion and fatigue (MiBaLeB)”, the short-time procedure, StrainLife, was developed and validated by several fatigue tests. With this procedure, a complete S–N curve of a material can be determined on the basis of three fatigue tests only, which reduces the effort compared to a conventional approach significantly and is thus ideal for assessing the condition of aged material, where the material is often rare, and a cost-effective answer is often very needed. The procedure described is not just limited to traditional parameters, such as stress and strain, considered in destructive testing but rather extends into parameters derived from non-destructive testing, which may allow further insight into what may be happening within a material’s microstructure. To evaluate the non-destructive quantities measured within the StrainLife procedure and to correlate them with the aging process in a material, several fatigue tests were performed on unnotched and notched specimens under cyclic loading at room and elevated temperatures, as well as under various media conditions, such as distilled water and reactor pressure vessel boiling water (BWR) conditions

    Patients with Intolerance Reactions to Total Knee Replacement: Combined Assessment of Allergy Diagnostics, Periprosthetic Histology, and Peri-implant Cytokine Expression Pattern

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    We performed a combined approach to identify suspected allergy to knee arthroplasty (TKR): patch test (PT), lymphocyte transformation test (LTT), histopathology (overall grading; T- and B-lymphocytes, macrophages, and neutrophils), and semiquantitative Real-time-PCR-based periprosthetic inflammatory mediator analysis (IFN gamma, TNF alpha, IL1-beta, IL-2, IL-6, IL-8, IL-10, IL17, and TGF beta). We analyzed 25 TKR patients with yet unexplained complications like pain, effusion, and reduced range of motion. They consisted of 20 patients with proven metal sensitization (11 with PT reactions;9 with only LTT reactivity). Control specimens were from 5 complicated TKR patients without metal sensitization, 12 OA patients before arthroplasty, and 8 PT patients without arthroplasty. Lymphocytic infiltrates were seen and fibrotic (Type IV membrane) tissue response was most frequent in the metal sensitive patients, for example, in 81% of the PT positive patients. The latter also had marked periprosthetic IFN gamma expression. 8/9 patients with revision surgery using Ti-coated/oxinium based implants reported symptom relief. Our findings demonstrate that combining allergy diagnostics with histopathology and periprosthetic cytokine assessment could allow us to design better diagnostic strategies

    Influence of the barotropic mean flow on the width and the structure of the Atlantic Equatorial Deep Jets

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    A representation of an equatorial basin mode excited in a shallow water model for a single high order baroclinic vertical normal mode is used as a simple model for the equatorial deep jets. The model is linearized about both a state of rest and a barotropic mean flow corresponding to the observed Atlantic Equatorial Intermediate Current System. We found that the eastward mean flow associated with the North and South Intermediate Counter Currents (NICC and SICC, respectively) effectively shields the Equator from off-equatorial Rossby waves. The westward propagation of these waves is blocked and focusing on the Equator due to beta dispersion is prevented. This leads to less energetic jets along the Equator. On the other hand, the westward barotropic mean flow along the Equator reduces the gradient of absolute vorticity and hence widens the cross-equatorial structure of the basin mode. Increasing lateral viscosity predominantly affects the width of the basin modes’ Kelvin wave component in the presence of the mean flow while the Rossby wave is confined by the flanking NICC and SICC. Independent of the presence of the mean flow, the application of sufficient lateral mixing also hinders the focusing of off-equatorial Rossby waves, which is hence an unlikely feature of a low-frequency basin mode in the real ocean
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