Update on Achalasia Treatment

Achalasia is a primary motility disorder of the esophagus characterized by failure of relaxation of the lower esophageal sphincter (LES) and aperistalsis of the esophagus. There are 3 types of achalasia, diagnosed and differentiated according to the Chicago classification using high resolution manometry (HRM). The classic symptoms of achalasia as described by the Eckardt score are dysphagia, retrosternal pain, regurgitation and weight loss. This chapter will discuss the interesting evolution of achalasia in the modern era, the ways to diagnose achalasia, different sub-groups within achalasia patients population, treat it with either endoscopic or surgical manner, pre-operative and post-operative considerations and routine follow-up

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

Abstract 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

The Biomimetic Evolution of Composite Materials: From Straw Bricks to Engineering Structures and Nanocomposites

Advanced polymer-based composite materials have revolutionized the structural material arena since their appearance some 60 years ago. Yet, despite their relatively short existence, they seem to be taken for granted as if they have always been there. One of the reasons for this state of affairs is that composite materials of various types have accompanied human history for thousands years, and their emergence in the modern era could be considered a natural evolutionary process. Nevertheless, the continuous line that leads from early days of composites in human history to current structural materials has exhibited a number of notable steps, each generating an abrupt advance toward the contemporary new science of composite materials. In this paper, I review and discuss the history of composites with emphasis on the main steps of their development

Why Do Nanoparticles (CNTs) Reduce the Glass Transition Temperature of Nanocomposites?

This ‘opinion’ article has been undertaken to provide a plausible answer to the question of why nanocomposites that are reinforced by acicular nanoparticles such as carbon nanotubes (CNTs) do not exhibit the anticipated physical properties—particularly, why the glass transition temperature in some compositions exhibits huge decreases, contrary to expectations. It is claimed that this behavior is typical of fully exfoliated, uniformly dispersed nanocomposites, whose structure is that of molecular composites or solid solutions, and which abide by colligative rules

The electrical conductivity of graphite nanoplatelet filled conjugated polyacrylonitrile

The electrical conductivity of composites of exfoliated graphite nanoplatelets (GNPs), including bromine-doped GNP, and conjugated polyacrylonitrile has been investigated. The focal point is the dual nature of the graphite nanoparticles, which exhibit both intrinsic electrical conductivity and doping capability of semiconductive polymers such as conjugated polyacrylonitrile to form charge-transfer complexes. The conductivity is particularly enhanced in conjugated polyacrylonitrile composites (e.g., with 6 wt.-\% graphite nanoplatelets) where the value rises from 1 x 10-'' to 2 x 10-' S - cm-', which reflects jointly the conductivity of the doped semi-conductive polymer together with the percolation-based conduc- A tivity of the particles

Hybrid effects in the fracture toughness of polyvinyl butyral-based nanocomposites

Hybrid polyvinyl butyral (PVB) nanocomposite films comprising surface-treated carbon nanotubes (CNT-COOH) and nanoclays (NC) were tested for their “trouser-leg” fracture toughness in comparison to the values of the respective CNT and NC parent composites and to that of the pristine PVB film. Relative to the fracture toughness of the pristine PVB, the parent composites PVB/CNT-COOH-0.2% and PVB/NC-2% and the PVB/CNT-COOH-0.2%/NC-2% hybrid exhibited 105, 118, and 181% improvements, respectively. These were both impressive fracture toughness improvements and a significant hybrid effect – the latter being only slightly lower than the nominal maximum effect of 223% based on the combined improvements of the parent composites. Part of the samples was tested qualitatively by ball impact test of ballistic glass samples with relevant films. Among these samples, the hybrid film presented the best result. A significant linear correlation between fracture surface energy and roughness values was taken to reflect a fracture resistance mechanism of crack front slowdown by its interactions with nanoparticles

Formation of Organic Nanoparticles by Electrospinning of Volatile Microemulsions

This study presents a method for one-step formation of poly­(ethylene oxide) nanofibers incorporating nanoparticles of a poorly water-soluble compound. Using the new method reported here, nanofiber–nanoparticle composites are fabricated in one step by electrospinning of an oil-in-water microemulsion, in which a model material, propylparaben, has been dissolved within the volatile dispersed phase in the presence of a high-molecular-weight polymer. The approach is based on nanoscale confinement to the dispersed phase of an oil-in-water microemulsion with a volatile oil phase, in which the poorly water-soluble materials are dissolved. Thus, when the thermodynamically stable oil-in-water microemulsion is combined with the rapid evaporation of solvent inherent in the electrospinning process, the droplets are converted into organic nanoparticles embedded within a polymeric nanofiber. In addition to possessing process simplicity, this method exhibits a very high percentage of nanoparticle loading with desirable active material properties. Specifically, the diameter of the nanofibers is in the range of 60–185 nm, and propylparaben exists within the nanofiber as nanocrystals of 30–120 nm. These dimensions suggest that the nanofiber–nanocrystal composites could serve as a delivery system for water-insoluble materials

Dispersion and functionalization of carbon nanotubes for polymer-based nanocomposites: A review

Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multifunctional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted. (c) 2010 Elsevier Ltd. All rights reserved