Failure of non-vacuum steam sterilization processes for dental handpieces

Background: Dental handpieces are used in critical and semi-critical operative interventions. Although a number of dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0·8-2·3mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. Aim: To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. Methods: In-vitro and in-vivo investigations were conducted on commonly used UK benchtop steam sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM) methods (dataloggers), chemical indicators (CI) and biological indicators (BI). Findings: All three methods of assessing achievement of sterility within dental handpieces that had been exposed to non-vacuum sterilization conditions demonstrated a significant number of failures (CI=8/3,024(fails/n tests); BI=15/3,024; TM=56/56) compared to vacuum sterilization conditions (CI=2/1,944; BI=0/1,944; TM=0/36). The dental handpiece most likely to fail sterilization in the non-vacuum process was the surgical handpiece. Non-vacuum sterilizers located in general dental practice had a higher rate of sterilization failure (CI=25/1,620; BI=32/1,620; TM=56/56) with no failures in vacuum process. Conclusion: Non-vacuum downward/gravity displacement, type-N steam sterilizers are an unreliable method for sterilization of dental handpieces in general dental practice. The handpiece most likely to fail sterilization is the type most frequently used for surgical interventions

Investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non-vacuum or vacuum processes

Background: Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices, are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organisations still advocate non-vacuum sterilization processes for these devices. Aim: To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Methods: Measurements at different positions within air turbines were undertaken with thermocouples and dataloggers. Two examples of commonly used UK benchtop steam sterilizers were tested; a non-vacuum benchtop sterilizer (Little Sister 3, Eschmann, UK) and a vacuum benchtop sterilizer (Lisa, W&H, Austria). Each sterilizer cycle was completed with three handpieces and each cycle in triplicate. Findings: A total of 140 measurements inside dental handpiece lumens were recorded. We demonstrate that the non-vacuum process fails (time range 0-150 seconds) to reliably achieve sterilization temperatures within the time limit specified by the International standard (15 seconds equilibration time). The measurement point at the base of the handpiece failed in all test runs (n=9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Conclusion: Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces and the base of the handpiece is the site most likely to fail

Evaluation of the Community Group Programme for Children & Young People: final report

The report presents findings from the evaluation of the Community Group Programme (CGP). The CGP is a 12-week psycho-educational, group work programme for children and young people who have experienced domestic violence. The Programme was developed in Canada and is being rolled out in England for the first time across 32 London boroughs. The programme is unique in working with children and their mothers concurrently and in a child-focused way. The study takes a theory-driven approach to evaluation. We employ a mixed method research strategy to answer questions of process (how does the CGP work?), impact (does the CGP make a difference and, if so, what sort of difference), salience (does the CGP matter to children and mothers and if so, in what ways?) and cost (what is the cost of CGP?). The final report presents findings from questionnaires, interviews and focus groups with children, mothers and professionals

It’s gender Jim, but not as we know it … A critical review of constructions of gendered knowledge of the global south

This article explores how research helps construct a certain type of ‘gender’ knowledge that arises from, informs and reinforces ‘instrumentalist’ gendered policy perspectives on development of the Global South. It uses a case study of research funded under the ESRC-DFID Joint Fund for Poverty Alleviation which awarded 122 grants amounting to £66.2 million (around US$88 million) between 2005 and 2015. From a systematic review of the awards a typology of gender inclusion and exclusion was constructed that found 60% of all awards mentioned gender or included some level of gender analysis. The subsequent synthesis of the evidence suggested that in only 30% of all awards was the gendered knowledge produced central to the study and/or focused on better understanding gender roles, relations and identities. Applying a Feminist Institutionalist lens, the study highlights how institutional ideas around gender are reflected in the funding call specifications, and in turn influence how researchers ‘engendered’ their research, and the type of gendered knowledge produced. It finds much of the new gendered knowledge produced out of the Joint Fund emerged from non-gender focused research often produced by non-gendered researchers. It suggests that as gender becomes mainstreamed into research, and as more researchers ‘do gender’, so research becomes, conversely, less ‘gendered’. The ‘new’ gender knowledge produced may then merely evidence existing institutional policy positions rather than advance the policy agenda

CuRL: Neural curve layers for global image enhancement

We present a novel approach to adjust global image properties such as colour, saturation, and luminance using human-interpretable image enhancement curves, inspired by the Photoshop curves tool. Our method, dubbed neural CURve Layers (CURL), is designed as a multi-colour space neural retouching block trained jointly in three different colour spaces (HSV, CIELab, RGB) guided by a novel multi-colour space loss. The curves are fully differentiable and are trained end-to-end for different computer vision problems including photo enhancement (RGB-to-RGB) and as part of the image signal processing pipeline for image formation (RAW-to-RGB). To demonstrate the effectiveness of CURL we combine this global image transformation block with a pixel-level (local) image multi-scale encoder-decoder backbone network. In an extensive experimental evaluation we show that CURL produces state-of-the-art image quality versus recently proposed deep learning approaches in both objective and perceptual metrics, setting new state-of-the-art performance on multiple public datasets. Our code is publicly available at: https://github.com/sjmoran/CURL

Influence of Bound versus Non-Bound Stabilizing Molecules on the Thermal Stability of Gold Nanoparticles

© 2017 American Chemical Society. Knowledge concerning the sintering behavior of gold nanoparticles (AuNPs) allows for improved nanomaterials for applications such as printed electronics, catalysis and sensing. In this study, we examined the ability of a range of compounds to stabilize AuNPs against thermal sintering and compared compounds with and without functional groups that anchor the molecules to the nanoparticle surface. Thermal stability was characterized in terms of the temperature of the sintering event (TSE) as well as thermogravimetric analysis and scanning electron microscopy. We show that anchored stabilizing compounds with high thermal stability are effective at preventing the sintering of AuNPs until the decomposition of the compound. A TSE of 390 °C was achieved using 1-pyrenebutanethiol as stabilizer. Of the unanchored stabilizers, which were combined with butanethiol-capped AuNPs, two were found to be particularly effective: oleylamine (TSE ≈ 300 °C) and a perylenedicarboximide derivative (TSE ≈ 540 °C), the latter conferring an unprecedented level of thermal stability on ligand-stabilized AuNPs. When selecting stabilizers without anchoring groups, our results demonstrate the importance of choosing those that have an affinity with the capping ligands on the AuNPs to ensure a uniform mixture of AuNPs and stabilizer within a film

Chronic heart failure: epidemiology, investigation and management

Heart failure (HF) is a clinical syndrome characterized by dyspnoea, fatigue and fluid retention accompanied by objective evidence of cardiac dysfunction. The syndrome affects around 2% of the adult population, men more commonly than women (<80 years old), with the incidence and prevalence rising steeply with age. HF causes substantial morbidity and reduced life expectancy, and coronary artery disease accounts for two-thirds of cases in developed countries. Investigation is important to ascertain the diagnosis, identify the aetiology (which may be reversible) and give some indication of prognosis. The diagnosis of HF confers a significantly increased risk of hospital admission and death. Treatment has been revolutionized by large randomized controlled clinical trials studying the effects of antagonists of the renin–angiotensin–aldosterone, neutral endopeptidase and sympathetic nervous systems, and the effects of device therapy. Cardiac transplantation remains an option for patients who are severely symptomatic (and at high risk) despite optimal use of such therapy

A new dawn? The Roman Catholic Church and environmental issues

This is a PDF version of an article published in New Blackfriars© 1997. The definitive version is available at www.blackwell-synergy.com.This article discusses the stance of the Roman Catholic Church on environmental issues and argues that the Church tends to stay on the fringe rather than get involved. Some of the ways in which Roman Catholic theologians have incorporated environmental issues into theological reflection is discussed, as are environmental challenges facing the Church in Britain (conservation, resources, biodiversity, animal welfare, biotechnology, cooperate/individual ethics, environmental justice, economics/policy development, and global issues)