Results of Delorme's procedure for rectal prolapse

PURPOSE: This study was designed to examine the results of Delorme's procedure. METHODS: Thirty-two patients (24 males and 8 females, mean age, 70 years) underwent Delorme's procedure between 1978 and 1990 following symptoms lasting between two weeks and ten years. Thirteen patients had had 21 previous operations for prolapse. RESULTS: The mean operation time was 65 minutes. No blood transfusions were needed, there was no operative mortality, and only two patients had complications (one chest infection and one anastomotic dehiscence). No patients were lost to follow-up. Over a mean follow-up of 24 months (4 months to 4 years), 9 patients died of unrelated conditions. There were four recurrences (12.5 percent), two in patients who had each had two previous procedures. Incontinence improved in 46 percent. No patient became constipated and 50 percent of those constipated preoperatively improved. CONCLUSION: Although abdominal rectopexy is safe and has a low recurrence rate (< 5 percent), it involves the hazards of a laparotomy. In addition, up to 40 percent of patients become constipated after rectopexy which may be debilitating. Delorme's procedure has a low morbidity, results in good bowel function, and has a low recurrence rate. It can be performed on unfit patients with possible advantages over rectopexy and perhaps should be used more readily.     

Web-based environmental simulation: bridging the gap between scientific modeling and decision-making

Data availability in environmental sciences is growing rapidly. Conventional monitoring systems are collecting data at increasing spatial and temporal resolutions; satellites provide a constant stream of global observations, and citizen scientist generate local data with electronic gadgets and cheap devices. There is a need to process this stream of heterogeneous data into useful information, both for science and for decision-making. Advances in networking and computer technologies increasingly enable accessing, combining, processing, and visualizing these data. This Feature reflects upon the role of environmental models in this process. We consider models as the primary tool for data processing, pattern identification, and scenario analysis. As such, they are an essential element of science-based decision-making. The new technologies analyzed here have the potential to turn the typical top-down flow of information from scientists to users into a much more direct, interactive approach. This may accelerate the dissemination of environmental information to a larger community of users. It may also facilitate harvesting feedback, and evaluating simulations and predictions from different perspectives. However, the evolution poses challenges, not only to model development but also to the communication of model results and their assumptions, shortcomings, and errors.     

Intercomparisons of Mobility Size Spectrometers and Condensation Particle Counters in the Frame of the Spanish Atmospheric Observational Aerosol Network

Red Española de DMAs Ambientales (REDMAAS), the Spanish network of environmental differential mobility analyzers (DMAs), currently comprises six research groups involved in the measurement of atmospheric aerosol size distributions by means of DMAs. The aim of this network is to guarantee the good quality and comparability of the routine measurements carried out at each location and in diverse environments across Spain. In order to achieve this objective, one of its main activities is the annual intercomparison of mobility size spectrometers used within the network (five units of scanning mobility particle sizers [SMPS] and one ultrafine particle monitor [UFPM]). Here we report the 2main results obtained during the 2010–2012 campaigns, including a study on particle deposition in dryers used in ambient air sampling systems. In general, all instruments showed good performance with deviations in accepted tolerance. The intercomparisons have been proved to be a useful exercise to detect instrument problems, such as incorrect calibrations. DMA calibration checks were performed with polystyrene latex reference particles. Deviations of less than 1% were observed during the first year, which increased 4.7% during the last campaign. Some differences among the responses of different condensation particle counter (CPC) models were encountered, being mainly connected to the intrinsic characteristics of each counter. The comparison of UFPM with CPCs has given good results. The SMPS intercomparisons, especially for particles above 20 nm, have been within +/?15% tolerance. Regarding particle deposition in dryers used in sampling systems, particle penetration was lower than predicted by the recommended model. This result was probably due to the fact that not all the possible mechanisms were considered in the model.

Copyright 2015 American Association for Aerosol Research     

The in-line inspection of carbon anodes for aluminum production

In this paper, methods for measuring the quality of carbon anodes consumed in the commercial production of aluminum are discussed. The electrical and mechanical qualities of these anodes are important for the economic operation of the aluminum plant. While the investigation is ongoing, results from tests made at an aluminum reduction plant are included. The methods reviewed include direct resistivity measurement using core samples, ultrasonic measurement, the hammer method, analysis of the Hall effect, the four-probe method, and use of magnetic coils (various arrangements).     

Atomic force microscopy of collagen structure in bone and dentine revealed by osteoclastic resorption

Mineralised tissues such as bone consist of two material phases: collagen protein fibrils, secreted by osteoblasts, form model structures for subsequent deposition of mineral, calcium hydroxyapatite. Collagen and mineral are removed in a three-dimensional manner by osteoclasts during bone turnover in skeletal growth or repair. Bone active drugs have recently been developed for skeletal diseases, and there is revived interest in changes in the structure of mineralised tissues seen in disease and upon treatment. The resolution of atomic force microscopy and use of unmodified samples has enabled us to image bone and dentine collagen exposed by the natural process of cellular dissolution of mineralised matrix. The morphology of bone and dentine has been analysed when fully mineralised and after osteoclast-mediated bone resorption, and compared with results from other microscopy techniques. Banded type I collagen, with 66.5+/-1.4 nm axial D-periodicity and 62.2+/-7.0 nm diameter, has been identified within resorption lacunae in bone and 69.4+/-4.3 nm axial D-periodicity and 140.6+/-12.4 nm diameter in dentine substrates formed by human and rabbit osteoclasts, respectively. This observation suggests a route by which the material and morphological properties of bone collagen can be analysed in situ, compared with collagen from non-skeletal sites, and contrasted in diseases of medical importance, such as osteoporosis, where skeletal tissue is mechanically weakened.     

On the Influence of Crosslinker on Template Complexation in Molecularly Imprinted Polymers: A Computational Study of Prepolymerization Mixture Events with Correlations to Template-Polymer Recognition Behavior and NMR Spectroscopic Studies

Aspects of the molecular-level basis for the function of ethylene glycol dimethacrylate and trimethylolproprane trimethacrylate crosslinked methacrylic acid copolymers molecularly imprinted with (S)-propranolol have been studied using a series of all-component and all-atom molecular dynamics studies of the corresponding prepolymerization systems. The crosslinking agents were observed to contribute to template complexation, and the results were contrasted with previously reported template-recognition behavior of the corresponding polymers. Differences in the extent to which the two crosslinkers interacted with the functional monomer were identified, and correlations were made to polymer-ligand recognition behavior and the results of nuclear magnetic resonance spectroscopic studies studies. This study demonstrates the importance of considering the functional monomer–crosslinker interaction when designing molecularly imprinted polymers, and highlights the often neglected general contribution of crosslinker to determining the nature of molecularly imprinted polymer-template selectivity.     

Erosion, corrosion and erosion–corrosion of EB PVD thermal barrier coatings

Electron beam (EB) physical vapour deposited (PVD) thermal barrier coatings (TBCs) have been used in gas turbine engines for a number of years. The primary mode of failure is attributed to oxidation of the bond coat and growth of the thermally grown oxide (TGO), the alumina scale that forms on the bond coat and to which the ceramic top coat adheres. Once the TGO reaches a critical thickness, the TBC tends to spall and expose the underlying substrate to the hot gases. Erosion is commonly accepted as a secondary failure mechanism, which thins the TBC thus reducing its insulation capability and increasing the TGO growth rate. In severe conditions, erosion can completely remove the TBC over time, again resulting in the exposure of the substrate, typically Ni-based superalloys. Since engine efficiency is related to turbine entry temperature (TET), there is a constant driving force to increase this temperature. With this drive for higher TETs comes corrosion problems for the yttria stabilised zirconia (YSZ) ceramic topcoat. YSZ is susceptible to attack from molten calcium–magnesium–alumina–silicates (CMAS) which degrades the YSZ both chemically and micro-structurally. CMAS has a melting point of around 1240 °C and since it is common in atmospheric dust it is easily deposited onto gas turbine blades. If the CMAS then melts and penetrates into the ceramic, the life of the TBC can be significantly reduced. This paper discusses the various failure mechanisms associated with the erosion, corrosion and erosion–corrosion of EB PVD TBCs. The concept of a dimensionless ratio D/d, where D is the contact footprint diameter and d is the column diameter, as a means of determining the erosion mechanism is introduced and discussed for EB PVD TBCs.     

面向产品创新的计算机辅助概念设计系统的研究

将面向产品外形、布局、人机工程学的产品概念设计的研究提到一个新的高度.本文将产品几何特征拓广为涵盖几何特征、工程特征、语义特征等三大内容的产品组件特征,重组为总体特征、布局特征、形状特征和人机特征,以三元组、条件约束集、多值依赖图建立组件特征模型,进而,建立了基于组件特征模型的产品信息模型,并研究了基于组件特征模型的产品布局设计技术、面向概念设计的人机工程设计技术,开发了一套计算机辅助概念设计系统.最后,以吸尘器概念设计为例,对本文提出的理论、方法、技术和系统加以验证,完成对机电信息一体化产品概念设计的支持.