Shear Capacity of Monolithic Concrete Joints without Transverse Reinforcement.

yesA mechanism analysis based on the upper-bound theorem of concrete plasticity for monolithic concrete joints without transverse reinforcement is presented. Concrete is modelled as a rigid–perfectly plastic material obeying modified Coulomb failure criteria. Existing stress–strain relationships of concrete in compression and tension are comprehensively modified using the crack band theory to allow for concrete type and maximum aggregate size. Simple equations for the effectiveness factor for compression, ratio of effective tensile strength to compressive strength and angle of concrete friction are then mathematically developed using the modified stress–strain relationships of concrete. In addition, 12 push-off specimens made of all-lightweight, sand–lightweight and normal-weight concrete having maximum aggregate size between 4 and 19 mm were physically tested. Test results and mechanism analysis clearly showed that the shear capacity of monolithic concrete joints increased with the increase of the maximum aggregate size and dry density of concrete. The mean and standard deviation of the ratio between experimentally measured and predicted (by the mechanism analysis shear capacities) are 1·01 and 0·16 respectively, showing a closer prediction and less variation than Vecchio and Collins' equation, regardless of concrete type and maximum aggregate size

Failure of a repeat course of cyclooxygenase inhibitor to close a PDA is a risk factor for developing chronic lung disease in ELBW infants

<p>Abstract</p> <p>Background</p> <p>The optimal treatment regimen or protocol for managing a persistent patent ductus arteriosus (PDA) in extremely low birth weight (ELBW) infants has not been well established. This study was aimed at evaluating the failure rate of a cyclooxygenase (COX) inhibitor (COI) for PDA closure and to determine the incidence of a PDA requiring ligation in ELBW infants. We examined the clinical characteristics and risk factors that may predict the clinical consequences of failure of PDA closure by COI.</p> <p>Methods</p> <p>Medical information on 138 infants with birth weight (BW) < 1000 gm who survived for > 48 hours was retrieved. Clinical characteristics and outcomes of patients whose PDAs closed with COI were compared with those who did not close.</p> <p>Results</p> <p>Of the 138 patients, 112 survived to discharge. Eighty (71.4%) of those who survived received 1-3 courses of COI treatment for a symptomatic PDA. A total of 32 (40%) failed COI treatment and underwent PDA ligation. Multivariable logistic regression analysis suggests that the observed differences in the outcomes in infants with or without symptomatic PDA can be explained by the babies with symptomatic PDA being more immature and sicker. No significant difference was seen in the incidence of chronic lung disease (CLD) in infants whose PDA was treated medically versus those who failed medical treatment and then underwent ligation. However, after adjusting for disease severity and other known risk factors, the odds ratio of developing CLD for surviving babies with a persistent PDA compared to those whose PDA was successfully closed with 1-2 courses of COI is 3.24 (1.07-9.81; p = 0.038).</p> <p>Conclusions</p> <p>When successfully treated, PDA in ELBW infants did not contribute significantly to the adverse outcomes such as CLD, retinopathy of prematurity (ROP) and age at discharge. This suggests that it is beneficial for a hemodynamically significant PDA to be closed. The failure of a repeat course of COI to close a PDA is a major risk factor for developing CLD in ELBW infants.</p

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

MicroRNA-10 Regulates the Angiogenic Behavior of Zebrafish and Human Endothelial Cells by Promoting Vascular Endothelial Growth Factor Signaling

RationaleFormation and remodeling of the vasculature during development and disease involve a highly conserved and precisely regulated network of attractants and repellants. Various signaling pathways control the behavior of endothelial cells, but their posttranscriptional dose titration by microRNAs is poorly understood.ObjectiveTo identify microRNAs that regulate angiogenesis.Methods and resultsWe show that the highly conserved microRNA family encoding miR-10 regulates the behavior of endothelial cells during angiogenesis by positively titrating proangiogenic signaling. Knockdown of miR-10 led to premature truncation of intersegmental vessel growth in the trunk of zebrafish larvae, whereas overexpression of miR-10 promoted angiogenic behavior in zebrafish and cultured human umbilical venous endothelial cells. We found that miR-10 functions, in part, by directly regulating the level of fms-related tyrosine kinase 1 (FLT1), a cell-surface protein that sequesters vascular endothelial growth factor, and its soluble splice variant sFLT1. The increase in FLT1/sFLT1 protein levels upon miR-10 knockdown in zebrafish and in human umbilical venous endothelial cells inhibited the angiogenic behavior of endothelial cells largely by antagonizing vascular endothelial growth factor receptor 2 signaling.ConclusionsOur study provides insights into how FLT1 and vascular endothelial growth factor receptor 2 signaling is titrated in a microRNA-mediated manner and establishes miR-10 as a potential new target for the selective modulation of angiogenesis

Microcurrent skin patches for postoperative pain control in total knee arthroplasty: a pilot study: A pilot study

Pain control following painful orthopaedic procedures such as total knee arthroplasty (TKA) is an ongoing challenge, as current pain management techniques often result in under-medication and/or complications. In a study designed to test the effect of the micro-current skin patch (MCT) on pain relief in patients following TKA, we followed 24 patients, randomly divided into two groups, one group receiving MCT plus tramadol hydrochloride (tramadol) for pain relief and a control group receiving only tramadol, for 10 days postoperatively. Tramadol was given intramuscularly in increment doses of 100 mg, as needed, for the duration of the study period. Pain was assessed daily using a visual analogue score (VAS). Other parameters, including the effect of MCT on the dose of tramadol needed for pain relief, the degree of wound healing measured at the end of the follow-up period, category of the wound 10 days postoperatively (1, 2 or 3) and total drain fluid volume, were also assessed. During the 10-day postoperative period there was a progressive decrease in pain in patients of both groups, however the patients of the MCT group showed a consistently lower VAS throughout the observation period, most markedly on those follow-up days with the highest pain scores in patients of the control group. This effect was monitored on the basis of the average dose of tramadol administered per day: 200.0±7.0 mg/day in the control group and 63.3±15.8 mg/day in the MCT group. Wound healing was better with the application of the MCT patch: grade 1 wounds were observed in 50% of the patients of the MCT group as compared to 8.3% in control group. The total drain volume was lower in patients of the MCT group compared to the controls (1020.8±211.6 and 1170.8±243.5 ml, respectively). None of the patients indicated that they wished to discontinue MCT therapy. This pilot study shows that MCT therapy led to better pain control with a markedly lower need for tramadol as compared to the control group. This better pain control was accompanied by a better healing of the wound and a lower drain volume