Prevalence and determinants of depression up to 5 years after colorectal cancer surgery: results from the ColoREctal Wellbeing (CREW) study.

AIM: Depression experienced by people with colorectal cancer (CRC) is an important clinical problem affecting quality of life. Recognition of depression at key points in the pathway enables timely referral to support. This study aimed to examine depression before and 5 years after surgery to examine its prevalence and identify determinants. METHOD: The ColoREctal Wellbeing (CREW) study is a prospective UK cohort study involving 872 adults with nonmetastatic CRC recruited before surgery with curative intent. Questionnaires completed before surgery and 3, 9, 15, 24, 36, 48 and 60 months after surgery captured socio-demographics and assessed depression (Centre for Epidemiologic Studies Depression Scale, CES-D) and other psychosocial factors. Clinical details were also gathered. We present the prevalence of clinically significant depression (CES-D ≥ 20) over time and its predictors assessed before and 2 years after surgery. RESULTS: Before surgery, 21.0% of the cohort reported CES-D ≥ 20 reducing to 14.7% 5 years after surgery. Presurgery risk factors predicting subsequent depression were clinically significant depression and anxiety, previous mental health service use, low self-efficacy, poor health, having neoadjuvant treatment and low social support. Postsurgery risk factors at 2 years predicting subsequent depression were clinically significant depression, negative affect, cognitive dysfunction, accommodation type and poor health. CONCLUSION: Depression is highly pervasive in people with CRC, exceeding prevalence in the general population across follow-up. Our findings emphasize the need to screen and treat depression across the pathway. Our novel data highlight key risk factors of later depression at important and opportune time points: before surgery and at the end of routine surveillance. Early recognition and timely referral to appropriate support is vital to improve long-term psychological outcomes.

Health and Social Care Diversity Among Individuals with Longstanding Physical and Psychological Health Problems: Pooled Repeated Cross Sectional Analyses.

This paper examines differences in health-and-social care utilisation for individuals with physical and/or mental health problems. Logistic regression models are used to determine disparity in the percentage of General Household/Lifestyle Survey participants with physical compared to mental health problems receiving disability benefits or health care services between 2000 and 2011. Our findings of a relative underutilisation of secondary health care combined with a relative overutilization of out-of-work benefits by individuals with mental health problems is novel to the field of rehabilitative health care. These results provide evidence for the previously suspected disparity in health care utilisation of individuals with mental health problems and indicate problems in labour force integration. The findings support the political call for a 'parity of esteem', which, in Britain, was enshrined in the Health and Social Care Act of 2012.

Cost analysis of open radical cystectomy versus robot-assisted radical cystectomy.

OBJECTIVES: To perform a cost analysis comparing the cost of robot-assisted radical cystectomy (RARC) with open RC (ORC) in a UK tertiary referral centre and to identify the key cost drivers. PATIENTS AND METHODS: Data on hospital length of stay (LOS), operative time (OT), transfusion rate, and volume and complication rate were obtained from a prospectively updated institutional database for patients undergoing RARC or ORC. A cost decision tree model was created. Sensitivity analysis was performed to find key drivers of overall cost and to find breakeven points with ORC. Monte Carlo analysis was performed to quantify the variability in the dataset. RESULTS: One RARC procedure costs £12 449.87, or £12 106.12 if the robot was donated via charitable funds. In comparison, one ORC procedure costs £10 474.54. RARC is 18.9% more expensive than ORC. The key cost drivers were OT, LOS, and the number of cases performed per annum. CONCLUSION: High ongoing equipment costs remain a large barrier to the cost of RARC falling. However, minimal improvements in patient quality of life would be required to offset this difference.

Comorbidities are associated with poorer quality of life and functioning and worse symptoms in the 5 years following colorectal cancer surgery: Results from the ColoREctal Well-being (CREW) cohort study.

OBJECTIVE: More people are living with the consequences of cancer and comorbidity. We describe frequencies of comorbidities in a colorectal cancer cohort and associations with health and well-being outcomes up to 5 years following surgery. METHODS: Prospective cohort study of 872 colorectal cancer patients recruited 2010 to 2012 from 29 UK centres, awaiting curative intent surgery. Questionnaires administered at baseline (pre-surgery), 3, 9, 15, 24 months, and annually up to 5 years. Comorbidities (and whether they limit activities) were self-reported by participants from 3 months. The EORTC QLQ-C30 and QLQ-CR29 assessed global health/quality of life (QoL), symptoms, and functioning. Longitudinal analyses investigated associations between comorbidities and health and well-being outcomes. RESULTS: At baseline, the mean age of participants was 68 years, with 60% male and 65% colon cancer. Thirty-two per cent had 1 and 40% had ≥2 comorbidities. The most common comorbidities were high blood pressure (43%), arthritis/rheumatism (32%), and anxiety/depression (18%). Of those with comorbidities, 37% reported at least 1 that limited their daily activities. Reporting any limiting comorbidities was associated with poorer global health/QoL, worse symptoms, and poorer functioning on all domains over 5-year follow-up. Controlling for the most common individual comorbidities, depression/anxiety had the greatest deleterious effect on outcomes. CONCLUSIONS: Clinical assessment should prioritise patient-reported comorbidities and whether these comorbidities limit daily activities, as important determinants of recovery of QoL, symptoms, and functioning following colorectal cancer. Targeted interventions and support services, including multiprofessional management and tailored assessment and follow-up, may aid recovery of health and well-being in these individuals.

Assessment of Multiple Membership Multilevel Models: An Application to Interviewer Effects on Nonresponse.

Multilevel multiple membership models account for situations where lower level units are nested within multiple higher level units from the same classification. Not accounting correctly for such multiple membership structures leads to biased results. The use of a multiple membership model requires selection of weights reflecting the hypothesized contribution of each level two unit and their relationship to the level one outcome. The Deviance Information Criterion (DIC) has been proposed to identify such weights. For the case of logistic regression, this study assesses, through simulation, the model identification rates of the DIC to detect the correct multiple membership weights, and the properties of model variance estimators for different weight specifications across a range of scenarios. The study is motivated by analyzing interviewer effects across waves in a longitudinal study. Interviewers can substantially influence the behavior of sample survey respondents, including their decision to participate in the survey. In the case of a longitudinal survey several interviewers may contact sample members to participate across different waves. Multilevel multiple membership models are suitable to account for the inclusion of higher-level random effects for interviewers at various waves, and to assess, for example, the relative importance of previous and current wave interviewers on current wave nonresponse. To illustrate the application, multiple membership models are applied to the UK Family and Children Survey to identify interviewer effects in a longitudinal study. The paper takes a critical view on the substantive interpretation of the model weights and provides practical guidance to statistical modelers. The main recommendation is that it is best to specify the weights in a multiple membership model by exploring different weight specifications based on the DIC, rather than prespecifying the weights.

Social support following diagnosis and treatment for colorectal cancer and associations with health-related quality of life: Results from the UK ColoREctal Wellbeing (CREW) cohort study.

OBJECTIVE: Social support is acknowledged as important in cancer survivorship, but little is known about change in support after cancer diagnosis and factors associated with this, particularly in colorectal cancer. The CREW cohort study investigated social support up to 2 years following curative intent surgery for colorectal cancer. METHODS: A total of 871 adults recruited pre-treatment from 29 UK centres 2010 to 2012 consented to follow-up. Questionnaires at baseline, 3, 9, 15, and 24 months post-surgery included assessments of social support (Medical Outcomes Study-Social Support Survey, MOS-SSS) and health-related quality of life (HRQoL). Socio-demographic, clinical and treatment details were collected. Longitudinal analyses assessed social support over follow-up, associations with participant characteristics, and HRQoL. RESULTS: Around 20% were living alone and 30% without a partner. Perceived social support declined in around 29% of participants, with 8% of these reporting very low levels overall from baseline to 2 years (mean MOS-SSS overall score < 40 on a scale from 0 to 100). Older age, female gender, greater neighbourhood deprivation, presence of co-morbidities, and rectal cancer site were significantly associated with reductions in perceived support. Poorer HRQoL outcomes (generic health/QoL, reduced wellbeing, anxiety, and depression) were significantly associated with lower levels of social support. CONCLUSIONS: Levels of social support decline following colorectal cancer diagnosis and treatment in nearly a third of patients and are an important risk factor for recovery of HRQoL. Assessment of support early on and throughout follow-up would enable targeted interventions to improve recovery, particularly in the more vulnerable patient groups at risk of poorer social support.

Recent applications in natural product synthesis of dihydrofuran and -pyran formation by ring-closing alkene metathesis.

In the past two decades, alkene metathesis has risen in prominence to become a significant synthetic strategy for alkene formation. Many total syntheses of natural products have used this transformation. We review the use, from 2003 to 2015, of ring-closing alkene metathesis (RCM) for the generation of dihydrofurans or -pyrans in natural product synthesis. The strategies used to assemble the RCM precursors and the subsequent use of the newly formed unsaturation will also be highlighted and placed in context.

A web-based intervention (RESTORE) to support self-management of cancer-related fatigue following primary cancer treatment: a multi-centre proof of concept randomised controlled trial.

PURPOSE: Cancer-related fatigue (CRF) is a frequent and distressing symptom experienced after cancer treatment. RESTORE is the first web-based resource designed to enhance self-efficacy to manage CRF following curative-intent treatment. The aim of this study is to test the proof of concept and inform the design of an effectiveness trial. METHODS: A multi-centre parallel-group two-armed (1:1) exploratory randomised controlled trial (RCT) with qualitative process evaluation was employed in the study. Participants (≥18 years; ≤5 years post treatment with moderate to severe fatigue) were recruited and randomly assigned to RESTORE or a leaflet. Feasibility and acceptability were measured by recruitment, attrition, intervention adherence, completion of outcome measures and process evaluation. Change in self-efficacy to manage CRF was also explored. Outcome measures were completed at baseline (T0), 6 weeks (T1) and 12 weeks (T2). Data were analysed using mixed-effects linear regression and directed content analysis. RESULTS: One hundred and sixty-three people participated in the trial and 19 in the process evaluation. The intervention was feasible (39 % of eligible patients consented) and acceptable (attrition rate 36 %). There was evidence of higher fatigue self-efficacy at T1 in the intervention group vs comparator (mean difference 0.51 [-0.08 to 1.11]), though the difference in groups decreased by 12 weeks. Time since diagnosis influenced perceived usefulness of the intervention. Modifications were suggested. CONCLUSION: Proof of concept was achieved. The RESTORE intervention should be subject to a definitive trial with some adjustments. Provision of an effective supportive resource would empower cancer survivors to manage CRF after treatment completion. TRIAL REGISTRATION: ISRCTN67521059.

HIV awareness in China among women of reproductive age (1997-2005): a decomposition analysis.

HIV prevalence in China is less than one per cent, but the absolute number of people living with HIV/AIDS is large and growing. Given the limited scope of any potential cure for HIV, prevention plays a crucial role in controlling the epidemic. This paper examines the evolution of HIV awareness among women in China between 1997 and 2005. A regression decomposition analysis technique was used to disentangle the two main components driving a change in HIV awareness. The results show that HIV awareness has increased over time in China. The gaps between groups are narrowing over time and lower HIV awareness groups are catching up with the higher awareness groups. In 2005 education remained one of the main factors associated with HIV awareness, the other main factors being ethnicity, exposure to TV and newspapers. The increases in HIV awareness observed between 1997 and 2001 are similar between groups of women with different demographic characteristics, whereas between 2003 and 2005 increases are more pronounced among specific groups of women such as women from rural areas, women from Western parts of the country, women who belong to ethnic minorities and those with no education or with only primary education. The results suggest that the main driver of the observed change in HIV awareness over time in China is change in the environment such as in political commitment, interventions and campaigns rather than change in population structure.

Lessons learnt recruiting to a multi-site UK cohort study to explore recovery of health and well-being after colorectal cancer (CREW study).

BACKGROUND: The UK leads the world in recruitment of patients to cancer clinical trials, with a six-fold increase in recruitment during 2001-2010. However, there are large variations across cancer centres. This paper details recruitment to a large multi-centre prospective cohort study and discusses lessons learnt to enhance recruitment. METHODS: During CREW (ColoREctal Wellbeing) cohort study set up and recruitment, data were systematically collected on all centres that applied to participate, time from study approval to first participant recruited and the percentage of eligible patients recruited into the study. RESULTS: 30 participating NHS cancer centres were selected through an open competition via the cancer networks. Time from study approval to first participant recruited took a median 124 days (min 53, max 290). Of 1350 eligible people in the study time frame, 78% (n = 1056) were recruited into the study, varying from 30-100% eligible across centres. Recruitment of 1056 participants took 17 months. CONCLUSION: In partnership with the National Cancer Research Network, this successful study prioritised relationship building and education. Key points for effective recruitment: pre-screening and selection of centres; nurses as PIs; attendance at study days; frequent communication and a reduced level of consent to enhance uptake amongst underrepresented groups.

Quality of life and health status in older adults (≥65 years) up to five years following colorectal cancer treatment: Findings from the ColoREctal Wellbeing (CREW) cohort study.

OBJECTIVE: Colorectal cancer (CRC) is common in older adults, with more than 70% of diagnoses in people aged ≥65 years. Despite this, there is a knowledge gap regarding longer-term outcomes in this population. Here, we identify those older people most at risk of poor quality of life (QoL) and health status in the five years following CRC treatment. MATERIALS AND METHODS: CREW is a UK longitudinal cohort study investigating factors associated with health and wellbeing recovery following curative-intent CRC surgery. Participants completed self-report questionnaires pre-surgery, then at least annually up to five years. Longitudinal analyses explored the prevalence and pre-surgery risk factors of poor QoL (QLACS-GSS) and health status (EQ-5D: presence/absence of problems in five domains) in older (≥65 years) participants over five years. RESULTS: 501 participants aged ≥65years completed questionnaires pre-surgery; 45% completed questionnaires five years later. Oldest-old participants (≥80 years) reported poorer QoL (18% higher QLACS-GSS) and 2-4 times higher odds of having problems with mobility or usual activities, compared with the youngest-old (65-69 years) over follow-up. Baseline higher self-efficacy was significantly associated with better QoL (10-30% lower QLACS-GSS scores compared to those with low self-efficacy) and lower odds of problems in all EQ-5D domains. Adequate social support was significantly associated with better QoL (8% lower QLACS-GSS) and lower odds of problems with usual activities (OR = 0.62) and anxiety/depression (OR = 0.56). CONCLUSION: There are important differences in QoL and health status outcomes for the oldest-old during CRC recovery. CREW reveals pre-surgery risk factors that are amenable to intervention including self-efficacy and social support.

Orphanhood and vulnerability: a conduit to poor child health outcomes in Rwanda.

The HIV epidemic in sub-Saharan Africa has caused many children to become orphaned and vulnerable. Recent studies show that orphaned and vulnerable children (OVC) lack the basic necessities for survival and development. These children are particularly at high risk of poor health and poverty. Although the poor health outcomes of these children are well documented, the complexities of the factors that mediate their health outcomes have not been systematically studied. The aim of this paper is to examine how the complex relationships between and within the proximate and socio-economic determinants mediate the poor health outcomes of children through their OVC status. The analyses considered graphical chain modelling of morbidity data from a sample of 3745 children aged below five years from the 2005 Rwandan Demographic and Health Survey. The results show that OVC status influences the risk of childhood morbidity both directly and indirectly and also as a conduit through which other significant proximate factors and socio-economic factors operate.

Management of irritable bowel syndrome in primary care: feasibility randomised controlled trial of mebeverine, methylcellulose, placebo and a patient self-management cognitive behavioural therapy website. (MIBS trial).

BACKGROUND: IBS affects 10-22% of the UK population. Abdominal pain, bloating and altered bowel habit affect quality of life, social functioning and time off work. Current GP treatment relies on a positive diagnosis, reassurance, lifestyle advice and drug therapies, but many suffer ongoing symptoms.A recent Cochrane review highlighted the lack of research evidence for IBS drugs. Neither GPs, nor patients have good evidence to inform prescribing decisions. However, IBS drugs are widely used: In 2005 the NHS costs were nearly £10 million for mebeverine and over £8 million for fibre-based bulking agents. CBT and self-management can be helpful, but poor availability in the NHS restricts their use. We have developed a web-based CBT self-management programme, Regul8, based on an existing evidence based self-management manual and in partnership with patients. This could increase access with minimal increased costs. METHODS/DESIGN: The aim is to undertake a feasibility factorial RCT to assess the effectiveness of the commonly prescribed medications in UK general practice for IBS: mebeverine (anti-spasmodic) and methylcellulose (bulking-agent) and Regul8, the CBT based self-management website.135 patients aged 16 to 60 years with IBS symptoms fulfilling Rome III criteria, recruited via GP practices, will be randomised to 1 of 3 levels of the drug condition: mebeverine, methylcellulose or placebo for 6 weeks and to 1 of 3 levels of the website condition, Regul8 with a nurse telephone session and email support, Regul8 with minimal email support, or no website, thus creating 9 groups. OUTCOMES: Irritable bowel symptom severity scale and IBS-QOL will be measured at baseline, 6 and 12 weeks as the primary outcomes. An intention to treat analysis will be undertaken by ANCOVA for a factorial trial. DISCUSSION: This pilot will provide valuable information for a larger trial. Determining the effectiveness of commonly used drug treatments will help patients and doctors make informed treatment decisions regarding drug management of IBS symptoms, enabling better targeting of treatment. A web-based self-management CBT programme for IBS developed in partnership with patients has the potential to benefit large numbers of patients with low cost to the NHS. Assessment of the amount of email or therapist support required for the website will enable economic analysis to be undertaken.

Consistency in reporting condom use between husbands and wives in Bangladesh.

Consistency in reporting contraceptive use between spouses is little understood, especially in developing settings. This research challenges the accuracy of measuring contraceptive prevalence rate, which is traditionally calculated based on women's responses. Multinomial logistic regression techniques are employed on a couple dataset from the 1999-2000 Bangladesh Demographic and Health Survey (DHS) to investigate the consistency in reporting condom use between husbands and wives. The level of inconsistency in reporting condom use was about 46%, of which about 32% was explained by husbands reporting condom use while wives did not, and 14% by wives reporting condom use while husbands did not. Regression analysis showed that couple education and age difference between the spouses are significant determinants of inconsistent reporting behaviour. The findings suggest the need for alternative approaches (questions) in the DHS to ensure consistency in the collection of data related to use of family planning methods.

A modular and divergent approach to spirocyclic pyrrolidines.

An efficient three-step sequence to afford a valuable class of spirocyclic pyrrolidines is reported. A reductive cleavage/Horner-Wadsworth-Emmons cascade facilitates the spirocyclisation of a range of isoxazolines bearing a distal ß-ketophosphonate. The spirocyclisation precursors are elaborated in a facile and modular fashion, via a [3 + 2]-cycloaddition followed by the condensation of a phosphonate ester, introducing multiple points of divergence. The synthetic utility of this protocol has been demonstrated in the synthesis of a broad family of 1-azaspiro[4,4]nonanes and in a concise formal synthesis of the natural product (±)-cephalotaxine.

Prevalence and predictors of poor sexual well-being over 5 years following treatment for colorectal cancer: results from the ColoREctal Wellbeing (CREW) prospective longitudinal study.

OBJECTIVES: To describe prevalence and predictors of poor sexual well-being for men and women over 5 years following treatment for colorectal cancer. DESIGN: Prospective longitudinal study, from presurgery to 5 years postsurgery, with eight assessment points. Logistic regression models predicted sexual well-being from presurgery to 24 months and 24 months to 60 months; time-adjusted then fully adjusted models were constructed at each stage. SETTING: Twenty-nine hospitals in the UK. PARTICIPANTS: Patients with Dukes' stage A-C, treated with curative intent, aged ≥18 years and able to complete questionnaires were eligible. OUTCOME MEASURES: The dependent variable was the Quality of Life in Adult Cancer Survivors sexual function score. Independent variables included sociodemographic, clinical and psychosocial characteristics. RESULTS: Seven hundred and ninety participants provided a sexual well-being score for at least one time point. Thirty-seven per cent of men and 14% of women reported poor sexual well-being at 5 years. Baseline predictors for men at 24 months included having a stoma (OR 1.5, 95% CI 1.02 to 2.20) and high levels of depression (OR 2.69/2.01, 95% CI 1.68 to 4.32/1.12 to 3.61); men with high self-efficacy (OR confident 0.33/0.48, 95% CI 0.18 to 0.61/0.24 to 1.00; very confident 0.25/0.42, 95% CI 0.13 to 0.49/0.19 to 0.94) and social support (OR 0.52/0.56, 95% CI 0.33 to 0.81/0.35 to 0.91) were less likely to report poor sexual well-being. Predictors at 60 months included having a stoma (OR 2.30/2.67, 95% CI 1.22 to 4.34/1.11 to 6.40) and high levels of depression (OR 5.61/2.58, 95% CI 2.58 to 12.21/0.81 to 8.25); men with high self-efficacy (very confident 0.14, 95% CI 0.047 to 0.44), full social support (OR 0.26; 95% CI 0.13 to 0.53) and higher quality of life (OR 0.97, 95% CI 0.95 to 0.98) were less likely to report poor sexual well-being. It was not possible to construct models for women due to low numbers reporting poor sexual well-being. CONCLUSIONS: Several psychosocial variables were identified as predictors of poor sexual well-being among men. Interventions targeting low self-efficacy may be helpful. More research is needed to understand women's sexual well-being.

Does quality of life return to pre-treatment levels five years after curative intent surgery for colorectal cancer? Evidence from the ColoREctal Wellbeing (CREW) study.

BACKGROUND: The ColoREctal Wellbeing (CREW) study is the first study to prospectively recruit colorectal cancer (CRC) patients, carry out the baseline assessment pre-treatment and follow patients up over five years to delineate the impact of treatment on health and wellbeing. METHODS: CRC patients received questionnaires at baseline (pre-surgery), 3, 9, 15, 24, 36, 48 and 60 months. The primary outcome was Quality of Life in Adult Cancer Survivors (QLACS); self-efficacy, mental health, social support, affect, socio-demographics, clinical and treatment characteristics were also assessed. Representativeness was evaluated. Predictors at baseline and at 24 months of subsequent worsened quality of life (QOL) were identified using multivariable regression models. RESULTS: A representative cohort of 1017 non-metastatic CRC patients were recruited from 29 UK cancer centres. Around one third did not return to pre-surgery levels of QOL five years after treatment. Baseline factors associated with worsened QOL included >2 comorbidities, neoadjuvant treatment, high negative affect and low levels of self-efficacy, social support and positive affect. Predictors at 24 months included older age, low positive affect, high negative affect, fatigue and poor cognitive functioning. CONCLUSIONS: Some risk factors for poor outcome up to five years following CRC surgery, such as self-efficacy, social support and comorbidity management, are amenable to change. Assessment of these factors from diagnosis to identify those most likely to need support in their recovery is warranted. Early intervention has the potential to improve outcomes.

HORIZONS protocol: a UK prospective cohort study to explore recovery of health and well-being in adults diagnosed with cancer.

INTRODUCTION: Understanding the impact of cancer and its treatment on people's everyday lives will help prepare people for what to expect, enable health professionals to predict likely recovery trajectories and shape care management according to needs. HORIZONS will recruit people awaiting treatment and follow them up at regular intervals to assess recovery of health and well-being. RESEARCH QUESTIONS: What impact does cancer diagnosis and treatment have on people's lives in the short, medium and long term? What are people's health and well-being outcomes, experiences and self-management activities over time across different cancer types and what influences these? How do people connect with and relate to others in mobilising resources that enable them to self-manage the consequences of cancer and treatment? METHODS AND ANALYSIS: HORIZONS is a multicentre, prospective cohort study exploring recovery of health and well-being in 3000 people diagnosed with breast cancer (<50 years), non-Hodgkin's lymphoma or gynaecological cancer. Recruitment will take place across National Health Service (NHS) sites in the UK between September 2016 and March 2019, before primary treatment starts. Participants will be identified through clinical teams and invited to complete questionnaires including assessments of quality of life, symptoms and functioning (Quality of Life in Adult Cancer Survivors; European Organisation for Research and Treatment Consortium Core quality of life questionnaire, EORTC-QLQ-C30), health status (EuroQol-5 dimensions, EQ-5D), self-efficacy, social support, social networks and lifestyle. Clinical data will also be collected. Descriptive statistics will characterise outcomes. Changes over time will be investigated. Factors that may influence recovery and self-management will be included in regression models to determine which influence health and well-being and self-management. ETHICS AND DISSEMINATION: Ethics and Health Research Authority approvals granted (IRAS Project ID: 202342, REC reference number 16/NW/0425). Adopted onto the National Institute for Health Research Clinical Research Network portfolio. We will engage with our Scientific Advisory Board, Tumour Specific Expert Panels, User Reference Group, Macmillan and the University of Southampton to ensure maximum publicity and benefit.

Implication of the knowledge and perceptions of veterinary students of antimicrobial resistance for future prescription of antimicrobials in animal health, South Africa.

Understanding the knowledge and perceptions of veterinary students of antimicrobial resistance (AMR) as potential future prescribers of antimicrobials may serve as an opportunity to improve stewardship of AMR. Pre-final (n = 42) and final (n = 29) year veterinary students of the University of Pretoria completed questionnaires to determine their knowledge and perceptions of AMR. Of the 71 respondents, mixed practice (48%) and small animal practice (45%) were the most preferred career choices post-graduation, with the field of gross pathology being the least preferred. Over 80% of the respondents believed that veterinary practitioners' misuse of antimicrobials contributes to AMR and a higher percentage (98.6%) believed that farmers' misuse of antimicrobials encourages the development of AMR, in particular, in food animals (60.6%) compared to companion animals (50.7%). Agreement in the ranking of abuse of antimicrobials between pre-final and final year students was fair (36.4%; kappa 0.3), and the most abused antimicrobials in descending order listed by the students were tetracyclines, penicillins, sulphonamides and aminoglycosides. There was wide disparity between training and potential field application, as well as variations in the correct matching of antimicrobials to their respective antibiotic classes. Responses to the clinical application of antimicrobials also varied widely. Despite the apparent teaching of AMR to veterinary students, gaps may exist in the translation of theoretical concepts to clinical applications, hence the need for focused and targeted antimicrobial prescription and stewardship training to bridge these potential identified gaps.

Carrier relaxation dynamics in lead sulfide colloidal quantum dots.

We report transient absorption saturation measurements on lead sulfide colloidal nanocrystals at the first and second exciton energies and fit the results to a model incorporating intraband and interband relaxation processes. We study in detail the Auger recombination from the first excited state, which takes place when more than one electron-hole pair is excited in a dot. We find an Auger coefficient of 4.5 x 10(-30) cm6/s for dots of 5.5 nm diameter, and observe saturation of the absorption bleaching when the (8-fold degenerate) first level is filled. We develop a model for the absorption dynamics using Poisson statistics and find a good fit with our experimental measurements.