Micromechanical homogenization of a hydrogel-filled electrospun scaffold for tissue-engineered epicardial patching of the infarcted heart: a feasibility study

For tissue engineering applications, accurate prediction of the effective mechanical properties of tissue scaffolds is critical. Open and closed cell modelling, mean-field homogenization theory, and finite element (FE) methods are theories and techniques currently used in conventional homogenization methods to estimate the equivalent mechanical properties of tissue-engineering scaffolds. This study aimed at developing a formulation to link the microscopic structure and macroscopic mechanics of a fibrous electrospun scaffold filled with a hydrogel for use as an epicardial patch for local support of the infarcted heart. The macroscopic elastic modulus of the scaffold was predicted to be 0.287 MPa with the FE method and 0.290 MPa with the closed-cell model for the realistic fibre structure of the scaffold, and 0.108 MPa and 0.540 MPa with mean-field homogenization for randomly oriented and completely aligned fibres. The homogenized constitutive description of the scaffold was implemented for an epicardial patch in a FE model of a human cardiac left ventricle to assess the effects of patching on myocardial mechanics and ventricular function in the presence of an infarct. Epicardial patching was predicted to reduce maximum myocardial stress in the infarcted LV from 19 kPa (no patch) to 9.5 kPa (patch) and to marginally improve the ventricular ejection fraction from 40% (no patch) to 43% (patch). This study demonstrates the feasibility of homogenization techniques to represent complex multiscale structural features in a simplified but meaningful and effective manner

In vitro antimicrobial comparison of three commercially available chlorhexidine-based oral rinses

INTRODUCTION: Commercially available chlorhexidine (CHX) formulations differ in their CHX concentrations (0.2% and 0.12%) as well as in various additives including alcohol, antimicrobials such as cetylpyridinium chloride and antidiscolouration chemicals such as ascorbic acid and sodium metabisulphite. AIMS AND OBJECTIVES: To compare in vitro the antimicrobial efficacies of three different CHX preparations (Corsodyl ®, Curasept® and GUM® Paroex®) using 0.2% and 0.12% CHX concentrations as controls METHODS: A disk diffusion test was performed using pure cultures of the organisms Streptococcus mutans and Candida albicans, and mixed cultures (facultative and strict anaerobes) prepared from oral rinse samples of 14 study participants. The means and standard deviations of the diameters of inhibition zones were calculated. RESULTS: A statistically significant difference (p value = 0.0001) was found only in Candida albicans cultures between the mean inhibition zones of the CHX preparation disks. Pure CHX preparations and Corsodyl® showed higher antifungal efficacy than Curasept® and GUM® Paroex Conclusion: Both CHX preparations (0.12% and 0.2%) and the 0.2% CHX preparation containing alcohol (Corsodyl®) have more potent antifungal properties against C. albicans than alcohol-free 0.12% CHX preparations such as Curasept® and GUM® Paroex®.DHE

Anisotropic diffusion of water molecules in hydroxyapatite nanopores

Funded by EPSRC Grant EP/K000128/1

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

Catastrophic instabilities in the fracture of nanotube bundles

[110527.EG : Selected papers from the 5th Forum on New Materials, part of CIMTEC 2010-12 th International Ceramics Congress and 5th Forum on New Materials, Montecatini Terme, Italy, June 13-18, 2010

Catastrophic instabilities in the fracture of nanotube bundles

[110527.EG <http://www.ttp.net/978-3-908158-59-2.html>: Selected papers from the 5th Forum on New Materials, part of CIMTEC 2010-12 th International Ceramics Congress and 5th Forum on New Materials, Montecatini Terme, Italy, June 13-18, 2010