Physical and chemical factors influencing the germination of Clostridium difficile spores

AIMS: To investigate the influence of chemical and physical factors on the rate and extent of germination of Clostridium difficile spores. METHODS AND RESULTS: Germination of C. difficile spores following exposure to chemical and physical germinants was measured by loss of either heat or ethanol resistance. Sodium taurocholate and chenodeoxycholate initiated germination together with thioglycollate medium at concentrations of 0.1-100 mmol l(-1) and 10-100 mmol l(-1) respectively. Glycine (0.2% w/v) was a co-factor required for germination with sodium taurocholate. There was no significant difference in the rate of germination of C. difficile spores in aerobic and anaerobic conditions (P > 0.05) however, the initial rate of germination was significantly increased at 37 degrees C compared to 20 degrees C (P < 0.05). The optimum pH range for germination was 6.5-7.5, with a decreased rate and extent of germination occurring at pH 5.5 and 8.5. CONCLUSIONS: This study demonstrates that sodium taurocholate and chenodeoxycholate initiate germination of C. difficile spores and is concentration dependant. Temperature and pH influence the rate and extent of germination. SIGNIFICANCE AND IMPACT OF THE STUDY: This manuscript enhances the knowledge of the factors influencing the germination of C. difficile spores. This may be applied to the development of potential novel strategies for the prevention of C. difficile infection.

The effect of ward design on the well-being of post-operative patients

Changes in the design of hospital wards have usually been determined by architects and members of the nursing and medical professions; the views and preferences of patients have seldom been sought directly. The Hospital Anxiety and Depression scale and the Disturbance Due to Hospital Noise questionnaire were administered to 64 female patients on bay and Nightingale wards together with a questionnaire designed for this study. Perceptions of social and physical factors of ward design were examined, and their relationship to psychological well-being and sleep patterns. The results show that the bay ward seemed to offer a more favourable environment for patients but some of the disadvantages of bay wards are balanced by better staffing levels and better and more modern facilities. Visibility to nurses was lower on the bay ward. The Nightingale ward was perceived as significantly noisier than the bay ward and noise levels were significantly correlated to anxiety scores. Paradoxically the increase in noise levels appeared to improve the perceived level of privacy on the Nightingale ward. Seventy-five per cent of patients were found to prefer the bay ward design, and since neither design appears to have major disadvantages their continued introduction should be encouraged. However, recommendations are made concerning the optimizing of patients' well-being within the bay ward setting.

Practice report: the role of environmental factors in industrial site selection activities: a case of limestone quarry expansion in Barbados, West Indies

Site selection is a key activity for quarry expansion to support cement production, and is governed by factors such as resource availability, logistics, costs, and socio-environmental factors. Adequate consideration of all factors facilitates both industrial productivity and sustainable economic growth. This study illustrates the site selection process that was undertaken for the expansion of limestone quarry operations to support cement production in Barbados. First, alternate sites with adequate resources to support a 25-year development horizon were identified. Second, socio-environmental conditions were described and potential impacts identified. Third, a comparative matrix was constructed to evaluate relative site characteristics with respect to physical, ecological, socio-cultural and economic factors. The study shows that environmental factors were essential to the final site recommendation.

Understanding the factors that affect the severity of juvenile stranger sex offenses

Understanding factors that affect the severity of a juvenile-stranger sexual assault has implications for crime prevention, and potentially, the assessment and treatment of juvenile sex offenders. This study investigated how victim characteristics and the number of suspects affected the use of physical violence and weapons and the occurrence of penetration in 495 allegations of sexual assault committed by juveniles against strangers. Statistically significant interactions between victim age and gender were found for occurrence of penetration and use of violence. Differences in offense characteristics were also found between offenses with varying victim-suspect age differences. When comparing the rate of penetration in the presence and absence of violence, little change was observed for lone suspects. However, the rate of penetration increased significantly for groups in the presence of physical violence, suggesting that violence in this context may be more expressive than instrumental. Theoretical explanations and practical implications are considered.

Effects of inducer continuity on auditory stream segregation:comparison of physical and perceived continuity in different contexts

The factors influencing the stream segregation of discrete tones and the perceived continuity of discrete tones as continuing through an interrupting masker are well understood as separate phenomena. Two experiments tested whether perceived continuity can influence the build-up of stream segregation by manipulating the perception of continuity during an induction sequence and measuring streaming in a subsequent test sequence comprising three triplets of low and high frequency tones (LHL-…). For experiment 1, a 1.2-s standard induction sequence comprising six 100-ms L-tones strongly promoted segregation, whereas a single extended L-inducer (1.1 s plus 100-ms silence) did not. Segregation was similar to that following the single extended inducer when perceived continuity was evoked by inserting noise bursts between the individual tones. Reported segregation increased when the noise level was reduced such that perceived continuity no longer occurred. Experiment 2 presented a 1.3-s continuous inducer created by bridging the 100-ms silence between an extended L-inducer and the first test-sequence tone. This configuration strongly promoted segregation. Segregation was also increased by filling the silence after the extended inducer with noise, such that it was perceived like a bridging inducer. Like physical continuity, perceived continuity can promote or reduce test-sequence streaming, depending on stimulus context.

Technology transfer to developing countries : the case of physical asset management in South Africa

This research investigates technology transfer (TT) to developing countries, with specific reference to South Africa. Particular attention is paid to physical asset management, which includes the maintenance of plant, equipment and facilities. The research is case based, comprising a main case study (the South African electricity utility, Eskom) and four mini-cases. A five level framework adapted from Salami and Reavill (1997) is used as the methodological basis for the formulation of the research questions. This deals with technology selection, and management issues including implementation and maintenance and evaluation and modifications. The findings suggest the Salami and Reavill (1997) framework is a useful guide for TT. The case organisations did not introduce technology for strategic advantage, but to achieve operational efficiencies through cost reduction, higher quality and the ability to meet customer demand. Acquirers favour standardised technologies with which they are familiar. Cost-benefit evaluations have limited use in technology acquisition decisions. Users rely on supplier expertise to compensate for poor education and technical training in South Africa. The impact of political and economic factors is more evident in Eskom than in the mini-cases. Physical asset management follows traditional preventive maintenance practices, with limited use of new maintenance management thinking. Few modifications of the technology or R&D innovations take place. Little use is made of explicit knowledge from computerised maintenance management systems. Low operating and maintenance skills are not conducive to the transfer of high-technology equipment. South African organisations acquire technology as items of plant, equipment and systems, but limited transfer of technology takes place. This suggests that operators and maintainers frequently do not understand the underlying technology, and like workers elsewhere, are not always inclined towards adopting technology in the workplace.

Studies of molecular interactions using physical techniques

The investigations described in this thesis concern the molecular interactions between polar solute molecules and various aromatic compounds in solution. Three different physical methods were employed. Nuclear magnetic resonance (n.m.r.) spectroscopy was used to determine the nature and strength of the interactions and the geometry of the transient complexes formed. Cryoscopic studies were used to provide information on the stoichiometry of the complexes. Dielectric constant studies were conducted in an attempt to confirm and supplement the spectroscopic investigations. The systems studied were those between nitromethane, chloroform, acetonitrile (solutes) and various methyl substituted benzenes. In the n.m.r. work the dependence of the solute chemical shift upon the compositions of the solutions was determined. From this the equilibrium quotients (K) for the formation of each complex and the shift induced in the solute proton by the aromatic in the complex were evaluated. The thermodynamic parameters for the interactions were obtained from the determination of K at several temperatures. The stoichiometries of the complexes obtained from cryoscopic studies were found to agree with those deduced from spectroscopic investigations. For most systems it is suggested that only one type of complex, of 1:1 stiochiometry, predominates except that for the acetonitrile-benzene system a 1:2 complex is formed. Two sets of dielectric studies were conducted, the first to show that the nature of the interaction is dipole-induced dipole and the second to calculate K. The equilibrium quotients obtained from spectroscopic and dielectric studies are compared. Time-averaged geometries of the complexes are proposed. The orientation of solute, with respect to the aromatic for the 1:1 complexes, appears to be the one in which the solute lies symmetrically about the aromatic six-fold axis whereas for the 1:2 complex, a sandwich structure is proposed. It is suggested that the complexes are formed through a dipole-induced dipole interaction and steric factors play some part in the complex formation.

Staying in nursing:what factors determine whether nurses intend to remain employed?

Aim. To test a model of eight thematic determinants of whether nurses intend to remain in nursing roles. Background. Despite the dramatic increase in the supply of nurses in England over the past decade, a combination of the economic downturn, funding constraints and more generally an ageing nursing population means that healthcare organizations are likely to encounter long-term problems in the recruitment and retention of nursing staff. Design. Survey. Method. Data were collected from a large staff survey conducted in the National Health Service in England between September-December 2009. A multi-level model was tested using MPlus statistical software on a sub-sample of 16,707 nurses drawn from 167 healthcare organizations. Results. Findings were generally supportive of the proposed model. Nurses who reported being psychologically engaged with their jobs reported a lower intention to leave their current job. The perceived availability of developmental opportunities, being able to achieve a good work-life balance and whether nurses' encountered work pressures were also influencing factors on their turnover intentions. However, relationships formed with colleagues and patients displayed comparatively small relationships with turnover intentions. Conclusion. The focus at the local level needs to be on promoting employee engagement by equipping staff with the resources (physical and monetary) and control to enable them to perform their tasks to standards they aspire to and creating a work environment where staff are fully involved in the wider running of their organizations, communicating to staff that patient care is important and the top priority of the organization. © 2012 Blackwell Publishing Ltd.

A need to consider human factors during manufacturing system design

Manufacturing systems that are heavily dependent upon direct workers have an inherent complexity that the system designer is often ill-equipped to understand. This complexity is due to the interactions that cause variations in performance of the workers. Variation in human performance can be explained by many factors, however one important factor that is not currently considered in any detail during the design stage is the physical working environment. This paper presents the findings of ongoing research investigating human performance within manufacturing systems. It sets out to identify the form of the relationships that exist between changes in physical working environmental variables and operator performance. These relationships can provide managers with a decision basis when designing and managing manufacturing systems and their environments.

Global and physical self-esteem and body dissatisfaction as mediators of the relationship between weight status and being a victim of bullying

Research has found evidence of a link between being overweight or obese and bullying/peer victimisation, and also between obesity and adjustment problems such as low self-esteem and body dissatisfaction. Studies have also found that adjustment problems can put children at an increased risk of being bullied over time. However, to date the factors that place overweight or obese children at risk of being bullied have been poorly elucidated. Self-report data were collected from a sample of 11-14 year olds (N=376) about their weight status, about their experiences of three different types of bullying (Verbal, Physical and Social), their global self-worth, self-esteem for physical appearance, and body dissatisfaction. Overweight or obese children reported experiencing significantly more verbal and physical (but not social) bullying than their non-overweight peers. Global self-worth, self-esteem for physical appearance and body dissatisfaction each fully mediated the paths between weight status and being a victim of bullying.

The role of environmental factors in industrial site selection activities:a case of limestone quarry expansion in Barbados, West Indies

Site selection is a key activity for quarry expansion to support cement production, and is governed by factors such as resource availability, logistics, costs, and socio-environmental factors. Adequate consideration of all factors facilitates both industrial productivity and sustainable economic growth. This study illustrates the site selection process that was undertaken for the expansion of limestone quarry operations to support cement production in Barbados. First, alternate sites with adequate resources to support a 25-year development horizon were identified. Second, socio-environmental conditions were described and potential impacts identified. Third, a comparative matrix was constructed to evaluate relative site characteristics with respect to physical, ecological, socio-cultural and economic factors. The study shows that environmental factors were essential to the final site recommendation.

Vascular endothelial growth factor promotes physical wound repair and is anti-apoptotic in primary distal lung epithelial and A549 cells

Objective: There is evidence to suggest a beneficial role for growth factors, including vascular endothelial growth factor (VEGF), in tissue repair and proliferation after injury within the lung. Whether this effect is mediated predominantly by actions on endothelial cells or epithelial cells is unknown. This study tested the hypothesis that VEGF acts as an autocrine trophic factor for human adult alveolar epithelial cells and that under situations of pro-apoptotic stress, VEGF reduces cell death. Design: In vitro cell culture study looking at the effects of 0.03% H2O2 on both A549 and primary distal lung epithelial cells.Measurement and Main Results: Primary adult human distal lung epithelial cells express both the soluble and membrane-associated VEGF isoforms and VEGF receptors 1 and 2. At physiologically relevant doses, soluble VEGF isoforms stimulate wound repair and have a proliferative action. Specific receptor ligands confirmed that this effect was mediated by VEGF receptor 1. In addition to proliferation, we demonstrate that VEGF reduces A549 and distal lung epithelial cell apoptosis when administered after 0.03% H2O2 injury. This effect occurs due to reduced caspase-3 activation and is phosphatidylinositol 3′–kinase dependent. Conclusion: In addition to its known effects on endothelial cells, VEGF acts as a growth and anti-apoptotic factor on alveolar epithelial cells. VEGF treatment may have potential as a rescue therapy for diseases associated with alveolar epithelial damage such as acute respiratory distress syndrome.

Risk factors for childhood myopia:findings from the NICER study

PURPOSE. We explored risk factors for myopia in 12- to 13-year-old children in Northern Ireland (NI). METHODS. Stratified random sampling was performed to obtain representation of schools and children. Cycloplegia was achieved using cyclopentolate hydrochloride 1%. Distance autorefraction was measured using the Shin-Nippon SRW-5000 device. Height and weight were measured. Parents and children completed a questionnaire, including questions on parental history of myopia, sociodemographic factors, childhood levels of near vision, and physical activity to identify potential risk factors for myopia. Myopia was defined as spherical equivalent ≤0.50 diopters (D) in either eye. RESULTS. Data from 661 white children aged 12-to 13-years showed that regular physical activity was associated with a lower estimated prevalence of myopia compared to sedentary lifestyles (odds ratio [OR] = 0.46 adjusted for age, sex, deprivation score, family size, school type, urbanicity; 95% confidence interval [CI], 0.23–0.90; P for trend = 0.027). The odds of myopia were more than 2.5 times higher among children attending academically-selective schools (adjusted OR = 2.66; 95% CI, 1.48–4.78) compared to nonacademically-selective schools. There was no evidence of an effect of urban versus nonurban environment on the odds of myopia. Compared to children with no myopic parents, children with one or both parents being myopic were 2.91 times (95% CI, 1.54–5.52) and 7.79 times (95% CI, 2.93– 20.67) more likely to have myopia, respectively. CONCLUSIONS. In NI children, parental history of myopia and type of schooling are important determinants of myopia. The association between myopia and an environmental factor, such as physical activity levels, may provide insight into preventive strategies.

Clogging in subsurface-flow treatment wetlands:occurrence and contributing factors

Clogging is a major operational and maintenance issue associated with the use of subsurface flow wetlands for wastewater treatment, and can ultimately limit the lifetime of the system. This review considers over two decades of accumulated knowledge regarding clogging in both vertical and horizontal subsurface flow treatment wetlands. The various physical, chemical and biological factors responsible for clogging are identified and discussed. The occurrence of clogging is placed into the context of various design and operational parameters such as wastewater characteristics, upstream treatment processes, intermittent or continuous operation, influent distribution, and media type. This information is then used to describe how clogging develops within, and subsequently impacts, common variants of subsurface flow treatment wetland typically used in the U.S., U.K., France and Germany. Comparison of these systems emphasized that both hydraulic loading rate and solids loading rate need to be considered when designing systems to operate robustly, i.e. hydraulic overloading makes horizontal-flow tertiary treatment systems in the U.K. more susceptible to clogging problems than vertical-flow primary treatment systems in France. Future research should focus on elucidating the underlying mechanisms of clogging as they relate to the design, operation, and maintenance of subsurface flow treatment wetlands. © 2010 Elsevier B.V.