83 research outputs found

    Strength Prediction Model for Power Acutated Fasteners Connecting Steel Members in Tension and Shear-north American Applications

    Get PDF
    Power-actuated fasteners (PAFs), also referred to as pins, are small nail-like or threaded stud t ype connectors. They can be used in conjunction with several materials and in a number of different applications. Typical applications in steel include attachments of deck sh eeting or diaphragms, architectural or mechanical components, or miscellaneous support brackets or connections to supporting steel members. Traditionally, the design strength of the connections featuring power-actuated fasteners has been determined through standardized testing protocols. In the United States, this protocol is embodied in the American Society for Testing and Materials (ASTM) Standard E 1190. The purpose of this study was to create a generic strength prediction model for pins embedded in steel substrate and subjected to either shear or tension, and to present the equations in a limit states fo rmat applicable to the North American practice and applications

    Ovarian Control of Nectar Collection in the Honey Bee (Apis mellifera)

    Get PDF
    Honey bees are a model system for the study of division of labor. Worker bees demonstrate a foraging division of labor (DOL) by biasing collection towards carbohydrates (nectar) or protein (pollen). The Reproductive ground-plan hypothesis of Amdam et al. proposes that foraging DOL is regulated by the networks that controlled foraging behavior during the reproductive life cycle of honey bee ancestors. Here we test a proposed mechanism through which the ovary of the facultatively sterile worker impacts foraging bias. The proposed mechanism suggests that the ovary has a regulatory effect on sucrose sensitivity, and sucrose sensitivity impacts nectar loading. We tested this mechanism by measuring worker ovary size (ovariole number), sucrose sensitivity, and sucrose solution load size collected from a rate-controlled artificial feeder. We found a significant interaction between ovariole number and sucrose sensitivity on sucrose solution load size when using low concentration nectar. This supports our proposed mechanism. As nectar and pollen loading are not independent, a mechanism impacting nectar load size would also impact pollen load size

    Second asymptomatic carotid surgery trial (ACST-2): a randomised comparison of carotid artery stenting versus carotid endarterectomy

    Get PDF
    Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence. Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362. Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86–1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91–1·32; p=0·21). Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable. Funding: UK Medical Research Council and Health Technology Assessment Programme

    The Herbst appliance combined with a completely customized lingual appliance: A retrospective cohort study of clinical outcomes using the American Board of Orthodontics Objective Grading System.

    No full text
    OBJECTIVES In this retrospective study we aimed to evaluate the quality of treatment outcomes using the American Board of Orthodontics (ABO) scoring system with a completely customized lingual appliance used in combination with a Herbst appliance for Class II correction. MATERIALS AND METHODS Patient selection criteria for this study were Class II division 1, II/2 or subdivision treated with a WINÂź lingual appliance combined with an L-pin Herbst device. Thirty-two consecutively debonded cases were included in this retrospective case series. Pre- and post- treatment dental casts, dental set-ups, panoramic X-rays, cephalometric analysis, photographs and clinical files were available for data collection. The primary outcome was the ABO score based on the Discrepancy Index (ABO DI) including: overjet, overbite, anterior open bite, lateral open bite, crowding, occlusion (Angle class), lingual posterior crossbite, buccal posterior crossbite, ANB, IMPA and SN-GoGN angles and the Cast-Radiograph Evaluation (ABO CR-Eval) comprising of alignment/rotations, marginal ridges, buccolingual inclination, overjet, occlusal contacts, occlusal relationship (Angle class), interproximal contacts and root angulation. In addition, overjet, overbite and Class II correction were also evaluated on pre- and post-treatment models. The secondary outcome was bracket failure and complications related to the Herbst device. RESULTS The study cohort included 18 female and 12 male patients with a mean age of 15.8 (range 12, 6- 18, 5). Twenty patients were Class II division 1 and ten were Class II division 2. The mean pre-treatment value of ABO DI was 20.8 (range 10-39); more than two-thirds of the sample were rated as being either of moderate difficulty (ABO DI: 16-24) or severe (ABO DI: over 25). The average post-treatment ABO Cast-Radiograph Evaluation score was 15.0 (SD=4.4), which is considered a passing score. Twenty-six patients had a score equal or lower than 20 (undisputed passing score). The Class II discrepancy was effectively corrected from a score of 16.83 penalty points (SD: 3.65) pre-treatment to a score of 1.57 (SD: 1.70) post-treatment. No association was found between initial and final Class II occlusal relationships (P=0.42), indicating that regardless of the initial discrepancy, no difference in the success of Class II correction was observed. The mean bracket failure rate was 3.8 per patient. Herbst related complications were few: 1.6 per patient, with the majority of complications being of little consequence and with 43% of the patients having no breakages. CONCLUSION The completely customized lingual appliance assessed in this study combined with an L-pin Herbst led to effective Class II correction regardless of the initial severity of the sagittal discrepancy. The average ABO CR-Eval score for this sample was well below the undisputed passing score indicating a high quality of treatment outcomes

    Update on pathogenesis and predictors of response of therapeutic strategies used in inflammatory bowel disease

    No full text
    The search for biomarkers that characterize specific aspects of inflammatory bowel disease (IBD), has received substantial interest in the past years and is moving forward rapidly with the help of modern technologies. Nevertheless, there is a direct demand to identify adequate biomarkers for predicting and evaluating therapeutic response to different therapies. In this subset, pharmacogenetics deserves more attention as part of the endeavor to provide personalized medicine. The ultimate goal in this area is the adjustment of medication for a patient’s specific genetic background and thereby to improve drug efficacy and safety rates. The aim of the following review is to utilize the latest knowledge on immunopathogenesis of IBD and update the findings on the field of Immunology and Genetics, to evaluate the response to the different therapies. In the present article, more than 400 publications were reviewed but finally 287 included based on design, reproducibility (or expectancy to be reproducible and translationable into humans) or already measured in humans. A few tests have shown clinical applicability. Other, i.e., genetic associations for the different therapies in IBD have not yet shown consistent or robust results. In the close future it is anticipated that this, cellular and genetic material, as well as the determination of biomarkers will be implemented in an integrated molecular diagnostic and prognostic approach to manage IBD patients

    Alterations in serotonin metabolism in the irritable bowel syndrome

    No full text
    Background Alterations in serotonin (5-HT) metabolism have been postulated to play a role in the pathogenesis of irritable bowel syndrome (IBS). However, previous reports regarding 5-HT metabolism in IBS are contradicting. Aim To compare platelet poor plasma (PPP) 5-HT and 5-hydroxyindole acetic acid (5-HIAA) levels and their ratio in a large cohort of IBS patients and healthy controls (HC), including IBS-subgroup analysis. Methods Irritable bowel syndrome patients and HC were evaluated for fasting PPP 5-HT and 5-HIAA levels. Furthermore, GI-symptom diary, GSRS, quality of life, anxiety and depression scores were assessed in the 2 weeks before blood sampling. Results One hundred and fifty four IBS patients and 137 HC were included. No differences were detected in plasma 5-HT between groups. The 5-HIAA concentrations and 5-HIAA/5-HT ratio were significantly lower in IBS compared to HC: 24.6 +/- 21.9 vs. 39.0 +/- 29.5 mu g/L (P <0.001) and 8.4 +/- 12.2 vs. 13.5 +/- 16.6 (P <0.01), respectively. Subtype analysis for 5-HIAA showed all IBS subtypes to be significantly different from HC. The 5-HIAA/5-HT ratio was significantly lower in the IBS-M subtype vs. HC. Linear regression analysis points to an influence of gender but not of GI-symptoms, psychological scores or medication use. Conclusions We demonstrated that fasting 5-HT plasma levels are not significantly different in IBS patients compared to controls. However, decreased 5-HIAA levels and 5-HIAA/5-HT ratio in IBS patients may reflect altered serotonin metabolism in IBS. Gender affects 5-HIAA levels in IBS patients, but no effects of drugs, such as SSRIs, or higher GI-symptom or psychological scores were found
    • 

    corecore