On the Existence of an Optimum End-to-side Junctional Geometry in Peripheral Bypass Surgery—A Computer Generated Study

AbstractBackground. To investigate hemodynamic flow changes associated with vein cuffs and patches that may be responsible for improved patency of prosthetic infrainguinal grafts.Methods. The role of the graft–artery junction angle was examined by computational fluid dynamics to assess the influence of anastomotic geometry on wall shear stress (WSS) distributions. Three geometrically different junction configurations were studied and the WSS and WSS gradient (WSSG) values were compared.Results. The inclusion of a patch or a cuff moves the bed stagnation point (BSP) distally, increasing the area on the bed of the junction which experiences a BSP and reducing the strength of the recirculation region opposite the heel of the junction by 54.8 and 50.8%, respectively. The patched geometry promotes earlier recovery of the flow in the distal outflow segment (DOS) than for the unpatched model. Also, the helical flow patterns in the DOS associated with the cuffed geometry are stronger. The net effect of these changes are that peak WSSG values for the patched and cuffed geometries are three times lower than those for the uncuffed geometry.Conclusion. This study provides some additional insights into the hemodynamics of graft–artery junction geometry which may influence future clinical practice

Structural investigation of GaInP nanowires using X-ray diffraction

AbstractIn this work the structure of ternary GaxIn1−xP nanowires is investigated with respect to the chemical composition and homogeneity. The nanowires were grown by metal–organic vapor-phase epitaxy. For the investigation of ensemble fluctuations on several lateral length scales, X-ray diffraction reciprocal space maps have been analyzed. The data reveal a complicated varying materials composition across the sample and in the nanowires on the order of 20%. The use of modern synchrotron sources, where beam-sizes in the order of several 10μm are available, enables us to investigate compositional gradients along the sample by recording diffraction patterns at different positions. In addition, compositional variations were found also within single nanowires in X-ray energy dispersive spectroscopy measurements

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Natural History of Periodontal Disease in Adults: Findings from the Tecumseh Periodontal Disease Study, 1959-87

The purpose of this epidemiological study was to estimate the degree of change in periodontal attachment level in a sample of adults examined in 1959 and 1987 in Tecumseh, Michigan. Out of 526 individuals between the ages of five and 60 years in 1959, a sample of 325 resided within an 80-km-radius area in 1987. Of those, 167 were re-examined. Loss of periodontal attachment (LPA) was determined with a Michigan #0 probe on four tooth sites (disto-buccal, mid-buccal, mesio-buccal, mid-lingual) for all teeth present. Of the individuals contacted, 28 had lost all their teeth during the 28 years. Of the 167 adults examined, two refused periodontal probing. Out of the 165 adults with LPA measurements in 1987, only 22 (13.3%) had an average increased loss of 2 mm or more per person between 1959 and 1987; five adults (3.0%) had an average LPA increase of 3 mm or more, and only two adults (1.2%) had an average LPA increase of 4 mm or more. The attachment level in 59.3% of all the tooth sites examined in 1959 in the 165 individuals either did not change or changed within ± 1.0 mm. On the basis of bivariate analyses, the individuals with high LPA increase (≥2 mm) had the following characteristics significantly different from those with low LPA increase: They were older, smoked, had tooth mobility at baseline, higher gingivitis, plaque, calculus, and tooth mobility scores at follow-up, lower education level, and irregular dental attendance. However, in logistic regression analyses, only the following risk markers remained significantly associated with high LPA increase: age, smoking, and presence of tooth mobility.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67852/2/10.1177_00220345900690020201.pd

A statistical survey of electron temperature enhancements in heater modulated polar mesospheric summer echoes at EISCAT

A statistical analysis has been made of 26 Polar Mesospheric Summer Echoes (PMSE) active modulation experiments between 2002 and 2007. Observed with the EISCAT VHF radar the PMSE signature can be reduced by means of heating the ionosphere with powerful high frequency (HF) radio waves. However, PMSE modulation experiments sometimes fail. We use a computational model to estimate the enhanced electron temperatures due to ionospheric heating from HF radio waves in the D-region. We show that the statistical PMSE modulation for a fixed HF heater-induced electron temperature enhancement appears to be independent of altitude. In addition, for experiments where the PMSE modulation experiment failed, we show that the atmospheric attenuation of the HF heater wave was too great for the HF wave to have any effect on the PMSE layer