Melt-extruded biocompatible surgical sutures loaded with microspheres designed for wound healing.

Sutures are commonly used in surgical procedures and have immense potential for direct drug delivery into the wound site. However, incorporating active pharmaceutical ingredients into the sutures has always been challenging as their mechanical strength deteriorates. This study proposes a new method to produce microspheres-embedded surgical sutures that offer adequate mechanical properties for effective wound healing applications. The study used curcumin, a bioactive compound found in turmeric, as a model drug due to its anti-inflammatory, antioxidant, and anti-bacterial properties, which make it an ideal candidate for a surgical suture drug delivery system. Curcumin-loaded microspheres were produced using the emulsion solvent evaporation method with polyvinyl alcohol (PVA) as the aqueous phase. The microspheres' particle sizes, drug loading (DL) capacity, and encapsulation efficiency (EE) were investigated. Microspheres were melt-extruded with polycaprolactone and polyethylene glycol via a 3D bioplotter, followed by a drawing process to optimise the mechanical strength. The sutures' thermal, physiochemical, and mechanical properties were investigated, and the drug delivery and biocompatibility were evaluated. The results showed that increasing the aqueous phase concentration resulted in smaller particle sizes and improved DL capacity and EE. However, if PVA was used at 3% w/v or below, it prevented aggregate formation after lyophilisation, and the average particle size was found to be 34.32 ± 12.82 µm. The sutures produced with the addition of microspheres had a diameter of 0.38 ± 0.02 mm, a smooth surface, minimal tissue drag, and proper tensile strength. Furthermore, due to the encapsulated drug-polymer structure, the sutures exhibited a prolonged and sustained drug release of up to 14 d. Microsphere-loaded sutures demonstrated non-toxicity and accelerated wound healing in thein vitrostudies. We anticipate that the microsphere-loaded sutures will serve as an excellent biomedical device for facilitating wound healing.

The intertwining roles of caveolin, oxytocin receptor, and the associated signalling pathways in prostate cancer progression.

Caveolae are invaginations in the plasma membrane of most cell types and are present in the cells of normal prostate tissue. Caveolins are a family of highly conserved integral membrane proteins that oligomerise to form caveolae and interact with signalling molecules by providing a scaffold that sequesters signal transduction receptors in close proximity to each other. Signal transduction G proteins and G-protein-coupled receptors (GPCR), including oxytocin receptor (OTR), are localised within caveolae. Only one OTR has been identified, and yet, this single receptor both inhibits and stimulates cell proliferation. As caveolae sequester lipid-modified signalling molecules, these differing effects may be due to a change in location. The cavin1 necessary for caveolae formation is lost in prostate cancer progression. With the loss of caveolae, the OTR moves out onto the cell membrane influencing the proliferation and survival of prostate cancer cells. Caveolin-1 (cav-1) is reportedly overexpressed in prostate cancer cells and is associated with disease progression. This review focuses on the position of OTRs within caveolae, and their movement out onto the cell membrane. It explores whether movement of the OTR is related to changes in the activation of the associated cell signalling pathways that may increase cell proliferation and analyse whether caveolin and particularly cavin1 might be a target for future therapeutic stratagies.

Urinary piperacillin/tazobactam pharmacokinetics in vitro to determine the pharmacodynamic breakpoint for resistant Enterobacteriaceae.

Urinary tract infections caused by multidrug-resistant Enterobacteriaceae are a growing burden worldwide. Recent studies of urinary pharmacokinetics described high piperacillin/tazobactam (TZP) concentrations in urine, but it is unknown whether this results in treatment efficacy. This study investigated the pharmacodynamics of TZP in a static in vitro model for Enterobacteriaceae to determine the concentration-effect relationship and ultimately the required free (unbound) time above the minimum inhibitory concentration (fT>MIC) required for bacterial killing. The static simulation model investigated TZP fT>MIC between 0% and 100%. Resistant Escherichia coli and Klebsiella pneumoniae isolates with piperacillin/tazobactam MICs of 4096/512, 1024/128 and 128/16 mg/L were investigated; two of the three organisms were carbapenemase-producers. Clinical efficacy was determined as a 3-log reduction over the dosing interval by comparing interval growth with controls. TZP was observed to exhibit time dependence for all organisms. The fT>MIC was determined to be 37.5%, 37.5% and 50% for MICs of 4096/512, 1024/128 and 128/16 mg/L, respectively. Linear regression identified the overall target to be 49.85 ± 16.9% fT>MIC. In conclusion, bactericidal activity against TZP-resistant Enterobacteriaceae occurred at 49.85 ± 16.9% fT>MIC. This suggests that highly resistant urinary organisms, including carbapenemase-producers, with MICs up to 4096/512 mg/L could be treated with TZP. Further investigations are required to elucidate urinary breakpoints and to explore the impact of different resistance mechanisms.

Changes in receptor location affect the ability of oxytocin to stimulate proliferative growth in prostate epithelial cells.

In normal prostate cells, cell membrane receptors are located within signalling microdomains called caveolae. During cancer progression, caveolae are lost and sequestered receptors move out onto lipid rafts. The aim of this study was to investigate whether a change in the localisation of receptors out of caveolae and onto the cell membrane increased cell proliferation invitro, and to determine whether this is related to changes in the cell signalling pathways. Normal human prostate epithelial cells (PrEC) and androgen-independent (PC3) cancer cells were cultured with 10nM dihydrotestosterone (DHT). The effects of oxytocin (OT) and gonadal steroids on proliferation were assessed using the MTS assay. Androgen receptor (AR) and oxytocin receptor (OTR) expression was identified by immunofluorescence and quantified by western blot. OTR and lipid raft staining was determined using Pearson's correlation coefficient. Protein-protein interactions were detected and the cell signalling pathways identified. Treatment with OT did not affect the proliferation of PrEC. In PC3 cells, OT or androgen alone increased cell proliferation, but together had no effect. In normal cells, OTR localised to the membrane and AR localised to the nucleus, whereas in malignant cells both OTR and AR were identified in the cell membrane. Colocalisation of OTR and AR increased following treatment with androgens. Significantly fewer OTR/AR protein-protein interactions were seen in PrEC. With OT treatment, several cell signalling pathways were activated. Movement of OTR out of caveolae onto lipid rafts is accompanied by activation of alternative signal transduction pathways involved in stimulating increased cell proliferation.

Pembrolizumab for advanced prostate adenocarcinoma: findings of the KEYNOTE-028 study.

Background: Patients with castration-resistant prostate cancer derive only modest clinical benefit from available therapies. Blockade of the inhibitory programmed death 1 (PD-1) receptor by monoclonal antibodies has been effective in several malignancies. Results from the prostate adenocarcinoma cohort of the nonrandomized phase Ib KEYNOTE-028 trial of pembrolizumab in advanced solid tumors are presented. Materials and methods: Key eligibility criteria included advanced prostate adenocarcinoma, unsuccessful standard therapy, measurable disease per Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1), and PD-1 ligand (PD-L1) expression in ≥1% of tumor or stromal cells. Patients received pembrolizumab 10 mg/kg every 2 weeks until disease progression or intolerable toxicity for up to 24 months. Primary end point was objective response rate (ORR) per RECIST v1.1 by investigator review. Results: Median patient age in this cohort (n = 23) was 65 years; 73.9% of patients received at least two prior therapies for metastatic disease. There were four confirmed partial responses, for an ORR of 17.4% [95% confidence interval (CI) 5.0%-38.8%]; 8 of 23 (34.8%) patients had stable disease. Median duration of response was 13.5 months. Median progression-free survival (PFS) and overall survival (OS) were 3.5 and 7.9 months, respectively; 6-month PFS and OS rates were 34.8% and 73.4%, respectively. One patient remained on treatment at data cutoff. After a median follow-up of 7.9 months, 14 (60.9%) patients experienced treatment-related adverse events (TRAEs), most commonly nausea (n = 3, 13.0%). Four (17.3%) experienced grade 3/4 TRAEs: grade 3 peripheral neuropathy, grade 3 asthenia, grade 3 fatigue, and grade 4 lipase increase. No pembrolizumab-related deaths or discontinuations occurred. Conclusion: Pembrolizumab resulted in durable objective response in a subset of patients with heavily pretreated, advanced PD-L1-positive prostate cancer, and its side effect profile was favorable. ClinicalTrials.gov Identifier: NCT02054806.

Labour market marginalisation subsequent to suicide attempt in young migrants and native Swedes.

PURPOSE: This study aimed to compare young individuals who differed in terms of birth region and history of suicide attempt regarding socio-demographic and healthcare factors, and with regard to their risks of subsequent unemployment, sickness absence and disability pension. METHODS: Prospective cohort study based on register linkage of 2,801,558 Swedish residents, aged 16-40 years in 2004, without disability pension and with known birth country, followed up 2005-2011. Suicide attempters treated in inpatient care during 2002-2004 (N = 9149) were compared to the general population of the same age without attempt 1987-2011 (N = 2,792,409). Hazard ratios (HR) and 95% confidence intervals (CIs) for long-term unemployment (>180 days), sickness absence (>90 days), and disability pension were calculated with Cox regression, adjusted for several risk markers. RESULTS: Compared to Swedish natives with suicide attempt, migrants of non-Western origin with attempt received less specialised mental healthcare. Distinct differences between native Swedes and migrants were present for the three labour market outcomes, but differences between migrant subgroups were inconsistent. As compared to native Swedes without attempts, non-European migrants with suicide attempt had adjusted HRs and CIs for subsequent unemployment 2.8 (2.5-3.1), sickness absence 2.0 (1.7-2.3) and disability pension 2.2 (1.8-2.6). Respective estimates for natives with suicide attempt were 2.0 (1.9-2.1); 2.7 (2.6-2.9) and 3.4 (3.2-3.6), respectively. CONCLUSIONS: Migrant suicide attempters receive less specialised mental health care before their attempt than native Swedes, and their marginalzation patterns are different. Healthcare and policy makers need to take the differential risk profile for migrant and native populations into account.

Predictors of psychological improvement on non-professional suicide message boards: content analysis.

BACKGROUND: Suicide message boards have been at the core of debates about negative influences of the Internet on suicidality. Nothing is currently known about communication styles that may help users to psychologically improve in these settings. METHOD: In all, 1182 archival threads with 20 499 individual postings from seven non-professional suicide message boards supporting an 'against-suicide', 'neutral' or 'pro-suicide' attitude were randomly selected and subject to content analysis. Initial needs of primary posters (i.e. individual who open a thread), their psychological improvement by the end of the thread, their responses received and indicators of suicidality were coded. Differences between 'pro-suicide', 'neutral' and 'against suicide' boards, and correlations between primary posters and respondents in terms of suicidality were assessed. Logistic regression was used to test associations with psychological improvement. RESULTS: 'Pro-suicide' boards (n = 4) differed from 'neutral' (n = 1) and 'against-suicide' (n = 2) boards in terms of communicated contents. Indicators of suicidality correlated moderately to strongly between primary posters and respondents on 'pro-suicide' message boards, but less on other boards. Several communicative strategies were associated with psychological improvement in primary posters, including the provision of constructive advice [adjusted odds ratio (aOR) 4.10, 95% confidence interval (CI) 2.40-7.03], active listening (aOR 1.60, 95% CI 1.12-2.27), sympathy towards the poster (aOR 2.22, 95% CI 1.68-2.95) and provision of alternatives to suicide (aOR 2.30, 95% CI 1.67-3.18). CONCLUSIONS: Respondents resemble primary posters with regard to suicidality in 'pro-suicide' boards, which may hinder psychological improvement. Still, opportunities to intervene in these settings using simple communication techniques exist and need to be taken and evaluated.

Depression symptom trends and health domains among lung cancer patients in the CanCORS study.

OBJECTIVES: Among lung cancer patients depression symptoms are common and impact outcomes. The aims of this study were to determine risk factors that contribute to persistent or new onset depression symptoms during lung cancer treatment, and examine interactions between depression symptoms and health domains that influence mortality. MATERIALS AND METHODS: Prospective observational study in five healthcare systems and 15 Veterans Affairs medical centers. Patients in the Cancer Care Outcomes Research and Surveillance (CanCORS) Consortium with lung cancer were eligible. The 8-item Center for Epidemiologic Studies Depression (CES-D) scale was administered at baseline and follow-up. Scores ≥4 indicated elevated depressive symptoms. Health domains were measured using validated instruments. We applied logistic regression and Cox proportional hazards modeling to explore the association between depression symptoms, health domains, and mortality. RESULTS: Of 1790 participants, 38% had depression symptoms at baseline and among those still alive, 31% at follow-up. Risk factors for depression symptoms at follow-up included younger age (OR=2.81), female sex (OR=1.59), low income (OR=1.45), not being married (OR=1.74) and current smoking status (OR=1.80); high school education was associated with reduced odds of depression symptoms at follow-up, compared with lesser educational attainment (OR=0.74) (all p values <0.05). Patients with depression symptoms had worse health-related quality of life, vitality, cancer-specific symptoms, and social support than patients without depression symptoms (all p<0.001). The association between depression symptoms and increased mortality is greater among patients with more lung cancer symptoms (p=0.008) or less social support (p=0.04). CONCLUSIONS: Patient risk factors for depression symptoms at follow-up were identified and these subgroups should be targeted for enhanced surveillance. Patients with depression symptoms suffer across all health domains; however, only more lung cancer symptoms or less social support are associated with worse mortality among these patients. These potentially modifiable health domains suggest targets for possible intervention in future studies.

The Quality of Colonoscopy Reporting in Usual Practice: Are Endoscopists Reporting Key Data Elements?

Background. High quality reporting of endoscopic procedures is critical to the implementation of colonoscopy quality assurance programs. Objective. The aim of our research was to (1) determine the quality of colonoscopy (CS) reporting in "usual practice," (2) identify factors associated with good quality reporting, and (3) compare CS reporting in open-access and non-open-access procedures. Methods. 557 CS reports were randomly selected and assigned a score based on the number of mandatory data elements included in the report. Reports documenting greater than 70% of the mandatory data elements were considered to be of good quality. Physician and procedure factors associated with good quality CS reporting were identified. Results. Variables that were consistently well documented included date of the procedure (99.6%), procedure indication (88.9%), a description of the most proximal anatomical segment reached (98.6%), and documentation of polyp location (97.8%). Approximately 79.4% of the reports were considered to be of good quality. Gastroenterology specialty, lower annual CS volume, and fewer years in practice were associated with good quality reporting. Discussion. CS reporting in usual practice in Ontario lacks quality in several areas. Almost 1 in 5 reports was of poor quality in our study. Conclusions. Targeted interventions and/or use of mandatory fields in synoptic reports should be considered to improve CS reporting.

Randomised clinical trial: alisporivir combined with peginterferon and ribavirin in treatment-naïve patients with chronic HCV genotype 1 infection (ESSENTIAL II).

BACKGROUND: Alisporivir (ALV) is an oral, host-targeting agent with pangenotypic anti-hepatitis C virus (HCV) activity and a high barrier to resistance. AIM: To evaluate efficacy and safety of ALV plus peginterferon-α2a and ribavirin (PR) in treatment-naïve patients with chronic HCV genotype 1 infection. METHODS: Double-blind, randomised, placebo-controlled, Phase 3 study evaluating ALV 600 mg once daily [response-guided therapy (RGT) for 24 or 48 weeks or 48 weeks fixed duration] or ALV 400 mg twice daily RGT with PR, compared to PR alone. Following a Food and Drug Administration partial clinical hold, ALV/placebo was discontinued and patients completed treatment with PR only. At that time, 87% of patients had received ≥12 weeks and 20% had received ≥24 weeks of ALV/PR triple therapy. RESULTS: A total of 1081 patients were randomised (12% cirrhosis, 55% CT/TT IL28B). Addition of ALV to PR improved virological response in a dose-dependent fashion. Overall, sustained virological response (SVR12; primary endpoint) was 69% in all ALV groups vs. 53% in PR control. Highest SVR12 (90%) was achieved in patients treated with ALV 400 mg twice daily and PR for >24 weeks. Seven cases of pancreatitis were reported, with similar frequency between ALV/PR and PR control groups (0.6% vs. 0.8% respectively). Adverse events seen more frequently with ALV/PR than with PR alone were anaemia, thrombocytopenia, hyperbilirubinaemia and hypertension. CONCLUSIONS: Alisporivir, especially the 400 mg twice daily regimen, increased efficacy of PR therapy in treatment-naïve patients with HCV genotype 1 infection. The mechanism of action and pangenotypic activity suggest that alisporivir could be useful in interferon-free combination regimens.

Global trends in teenage suicide: 2003-2014.

The object of this article is to review the past decade of research on teenage suicide, with a particular emphasis on epidemiologic trends by age, gender and indigenous ethnicity. As such, a review of research literature from 2003 to 2014 was conducted via a comprehensive search of relevant psychological and medical databases. Wide gaps in our knowledge base exist concerning the true extent of teenage suicide due to lack of data, particularly in developing countries, resulting in a Western bias. The gender paradox of elevated suicidality in females with higher completed suicide rates in males is observed in teenage populations worldwide, with the notable exceptions of China and India. Native and indigenous ethnic minority teens are at significantly increased risk of suicide in comparison to general population peers. Often those with the highest need for mental health care (such as the suicidal adolescent) have least access to therapeutic support.Globally, suicide in teenagers remains a major public health concern. Further focused research concerning completed suicides of youth below the age of 18 is required across countries and cultures to understand more about risk as children progress through adolescence. Gender and ethnic variations in suicidality are embedded within cultural, historical, psychological, relational and socio-economic domains. Worldwide, the absence of child/adolescent-specific mental health policies may delay the development of care and suicide prevention. Overall, it is vital that clinicians adopt a holistic approach that incorporates an awareness of age and gender influences, and that cultural competency informs tailored and evaluated intervention programmes.

Sunlight exposure and photoprotection behaviour of white Caucasian adolescents in the UK.

BACKGROUND: Sun exposure has positive and negative effects on health, yet little is known about the sun exposure behaviour of UK adolescents, including those more prone or less prone to sunburn. OBJECTIVE: To examine sun exposure behaviour of UK white Caucasian adolescents including time spent outdoors, holiday behaviour, use of sunscreen and clothing, with assessment for differences between sun-reactive skin type groups. METHODS: White Caucasian adolescents (12-15 years) attending schools in Greater Manchester completed a two-page questionnaire to assess sun exposure and photoprotective behaviour. RESULTS: A total of 133 adolescents (median age 13.4 years; 39% skin type I/II, 61% skin type III/IV) completed the questionnaire. In summer, adolescents spent significantly longer outdoors at weekends (median 4 h/day, range 0.25-10) than on weekdays (2, 0.25-6; P < 0.0001). When at home in the UK during summer, 44% reported never wearing sunscreen compared to just 1% when on a sunny holiday. Sunscreen use was also greater (frequency/coverage) when on a sunny holiday than at home in the UK summer (P < 0.0001). Adolescents of skin types I/II (easy burning) spent significantly less time outdoors than skin types III/IV (easy tanning) on summer weekends (P < 0.001), summer weekdays (P < 0.05) and on a sunny holiday (P = 0.001). Furthermore, skin types I/II reported greater sunscreen use during summer in the UK and on sunny holiday (both P < 0.01), and wore clothing covering a greater skin area on a sunny holiday (P < 0.01) than skin types III/IV. There was no difference in sun exposure behaviour/protection between males and females. CONCLUSION: The greater sun-protective measures reported by adolescents of sun-reactive skin type group I/II than III/IV suggest those who burn more easily are aware of the greater need to protect their skin. However, use of sunscreen during the UK summer is low and may need more effective promotion in adolescents.

Clinical supervision in a UK military Department of Community Mental Health.

OBJECTIVES: Recent service developments in the NHS on the provision of talking therapies such as the Improving Access to Psychological Therapies (IAPT) initiative have made the compliance with clinical supervision (CS) inherent among its service guidelines. This paper presents the findings of an audit, measuring compliance with CS among clinicians providing psychological therapies within a military Department of Community Mental Health. METHOD: Adherence to the recommended monthly supervision and the presence of an indate CS contract were audited on two separate occasions over 2 years by analysing the departmental electronic CS database. RESULTS: Compliance rates were found to be lower than the Defence guidelines, which are already modest in their expectations compared with IAPT CS standards. DISCUSSION: Potential reasons are hypothesised including high levels of staff rotation, other military commitments, clinicians not keeping up-to-date records and the pressures of meeting performance indicators on other clinical issues. Proposals for improving the uptake of CS are suggested along with areas for further research.

Decline in pulmonary function during chronic hepatitis C virus therapy with modified interferon alfa and ribavirin.

Rare interstitial lung disease cases have been reported with albinterferon alfa-2b (albIFN) and pegylated interferon alfa-2a (Peg-IFNα-2a) in chronic hepatitis C virus (HCV) patients. Systematic pulmonary function evaluation was conducted in a study of albIFN q4wk vs Peg-IFNα-2a qwk in patients with chronic HCV genotypes 2/3. Three hundred and ninety-one patients were randomly assigned 4:4:4:3 to one of four, open-label, 24-week treatment groups including oral ribavirin 800 mg/d: albIFN 900/1200/1500 µg q4wk or Peg-IFNα-2a 180 µg qwk. Standardized spirometry and diffusing capacity of the lung for carbon monoxide (DLCO) were recorded at baseline, weeks 12 and 24, and 6 months posttreatment, and chest X-rays (CXRs) at baseline and week 24. Baseline spirometry and DLCO were abnormal in 35 (13%) and 98 (26%) patients, respectively. Baseline interstitial CXR findings were rare (4 [1%]). During the study, clinically relevant DLCO declines (≥15%) were observed in 173 patients (48%), and were more frequent with Peg-IFNα-2a and albIFN 1500 µg; 24 weeks posttreatment, 57 patients (18%) still had significantly decreased DLCO, with a pattern for greater rates with albIFN vs Peg-IFNα-2a. One patient developed new interstitial CXR abnormalities, but there were no clinically relevant interstitial lung disease cases. The risk of persistent posttreatment DLCO decrease was not related to smoking, alcohol, HCV genotype, sustained virologic response, or baseline viral load or spirometry. Clinically relevant DLCO declines occurred frequently in chronic HCV patients receiving IFNα/ribavirin therapy and commonly persisted for ≥6 months posttherapy. The underlying mechanism and clinical implications for long-term pulmonary function impairment warrant further research.

Randomized trial of albinterferon alfa-2b every 4 weeks for chronic hepatitis C virus genotype 2/3.

Albinterferon alfa-2b (albIFN) is a fusion protein of recombinant human albumin/recombinant interferon (IFN)-α-2b, with ∼200-h half-life. Safety/efficacy of albIFN q4wk was evaluated in 391 treatment-naive patients with chronic hepatitis C virus (HCV) genotype 2/3. Patients were randomized 3:4:4:4 to one of four open-label treatment groups: pegylated IFN (Peg-IFN)-α-2a 180 µg qwk or albIFN 900, 1200 or 1500 µg q4wk, plus oral ribavirin 800 mg/day, for 24 weeks. Primary efficacy endpoint was sustained virologic response (SVR; HCV RNA <20 IU/mL 24 weeks post-treatment). SVR rates were as follows: 85%, 76%, 76% and 78% with Peg-IFNα-2a and albIFN 900, 1200 and 1500 µg, respectively (P = NS); corresponding rapid virologic response rates (HCV RNA <43 IU/mL at week 4) were as follows: 78%, 49% (P < 0.001), 60% (P = 0.01) and 71%. SVR rates were not influenced by interleukin 28B genotype, although rapid virologic response rates were greater with interleukin 28B CC (P = NS). Serious adverse event rates were as follows: 4%, 11%, 3% and 3% with Peg-IFNα-2a and albIFN 900, 1200 and 1500 µg, respectively. No increase in serious/severe respiratory events was noted with albIFN. Fewer absolute neutrophil count reductions <750/mm(3) occurred with albIFN (P = 0.03), leading to fewer IFN dose reductions. Haemoglobin reductions <10 g/dL were less frequent with albIFN 900 and 1200 µg vs 1500 µg and Peg-IFNα-2a (P = 0.02), leading to fewer ribavirin dose reductions. albIFN administered q4wk produced fewer haematologic reductions than Peg-IFNα-2a, but had numerically lower SVR rates (P = NS) in patients with chronic HCV genotype 2/3.

Bullying and the UK Armed Forces.

There are certain characteristics of the culture and environment in the Armed Forces that may be conducive to bullying. In this article we examine the cultural and environmental factors that may encourage such behaviour and those that act as deterrents for victims to come forward. We will look at the scope of this problem within the UK Armed Forces specifically, before more generally considering the psychological impact of bullying. There appears to be an overall downward trend in bullying within the UK Armed Forces and a positive increase in complaints as more victims step forward. We conclude by highlighting some areas for further development.

Judgments of approach speed for motorcycles across different lighting levels and the effect of an improved tri-headlight configuration.

The misperception of vehicle approach speed is a key contributory factor to road traffic crash involvement. Past research has indicated that individuals use the rate of visual looming to calculate the time to passage (TTP) of a vehicle, and that smaller vehicles loom to a lesser extent than larger vehicles. Despite a disproportionate number of fatal injuries occurring on the road after dark, and a higher than average number of accidents involving automobile drivers violating the right of way of a motorcyclist occurring in low light conditions, there has been very little consideration of the accuracy of TTP for smaller and larger vehicles under low levels of luminance. We investigated drivers' judgments of motorcycle and car approach speeds across a number of levels of luminance within a virtual city scene, as well as the effectiveness of a tri-headlight formation on motorcycle speed judgments. The accuracy of car approach speed judgments were not affected by changes in lighting conditions, but speed judgments for the solo headlight motorcycle became significantly less accurate as lighting reduced in the early night and night-time conditions. Incorporation of a tri-headlight formation onto the standard motorcycle frame resulted in improved accuracy of approach speed judgments, relative to the solo headlight motorcycle, as ambient light levels reduced. The practical implications of the findings are discussed in terms of road safety and motorcycle design.

Errors in judging the approach rate of motorcycles in nighttime conditions and the effect of an improved lighting configuration.

One of the key contributory factors for accident involvement is misjudgment of approach speed (Department for Transport, 2010). Past research has indicated that individuals can use the rate of visual looming in order to the judge time to passage (TTP) of approaching vehicles, and that smaller vehicles loom to a lesser extent than larger vehicles (e.g., Horswill et al., 2005). However, the judgment of TTP in nighttime conditions has received little attention. This paper explores drivers' abilities to make judgments of motorcycles and car approach speeds in nighttime driving conditions, when only the headlights are visible, as well as the effectiveness of a tri-headlight configuration on the accuracy of motorcycle speed judgments. Results showed that individuals were significantly more accurate at judging the speed of two car headlights compared with the standard solo headlight motorcycle. However, the inclusion of a tri-headlight formation on a standard motorcycle frame significantly improved these judgments. A further investigation demonstrated that tri-headlight configurations with separation between headlights on the horizontal and vertical axes are most effective for yielding accurate speed judgments. The implications of the results for road safety and motorcycle design are discussed.