Delivering clinical tutorials to medical students using the Microsoft HoloLens 2: A mixed-methods evaluation.

BACKGROUND: Mixed reality offers potential educational advantages in the delivery of clinical teaching. Holographic artefacts can be rendered within a shared learning environment using devices such as the Microsoft HoloLens 2. In addition to facilitating remote access to clinical events, mixed reality may provide a means of sharing mental models, including the vertical and horizontal integration of curricular elements at the bedside. This study aimed to evaluate the feasibility of delivering clinical tutorials using the Microsoft HoloLens 2 and the learning efficacy achieved. METHODS: Following receipt of institutional ethical approval, tutorials on preoperative anaesthetic history taking and upper airway examination were facilitated by a tutor who wore the HoloLens device. The tutor interacted face to face with a patient and two-way audio-visual interaction was facilitated using the HoloLens 2 and Microsoft Teams with groups of students who were located in a separate tutorial room. Holographic functions were employed by the tutor. The tutor completed the System Usability Scale, the tutor, technical facilitator, patients, and students provided quantitative and qualitative feedback, and three students participated in semi-structured feedback interviews. Students completed pre- and post-tutorial, and end-of-year examinations on the tutorial topics. RESULTS: Twelve patients and 78 students participated across 12 separate tutorials. Five students did not complete the examinations and were excluded from efficacy calculations. Student feedback contained 90 positive comments, including the technology's ability to broadcast the tutor's point-of-vision, and 62 negative comments, where students noted issues with the audio-visual quality, and concerns that the tutorial was not as beneficial as traditional in-person clinical tutorials. The technology and tutorial structure were viewed favourably by the tutor, facilitator and patients. Significant improvement was observed between students' pre- and post-tutorial MCQ scores (mean 59.2% Vs 84.7%, p < 0.001). CONCLUSIONS: This study demonstrates the feasibility of using the HoloLens 2 to facilitate remote bedside tutorials which incorporate holographic learning artefacts. Students' examination performance supports substantial learning of the tutorial topics. The tutorial structure was agreeable to students, patients and tutor. Our results support the feasibility of offering effective clinical teaching and learning opportunities using the HoloLens 2. However, the technical limitations and costs of the device are significant, and further research is required to assess the effectiveness of this tutorial format against in-person tutorials before wider roll out of this technology can be recommended as a result of this study.

Effect of interventions to improve safety culture on healthcare workers in hospital settings: a systematic review of the international literature.

BACKGROUND: In an era of safety systems, hospital interventions to build a culture of safety deliver organisational learning methodologies for staff. Their benefits to hospital staff are unknown. We examined the literature for evidence of staff outcomes. Research questions were: (1) how is safety culture defined in studies with interventions that aim to enhance it?; (2) what effects do interventions to improve safety culture have on hospital staff?; (3) what intervention features explain these effects? and (4) what staff outcomes and experiences are identified? METHODS AND ANALYSIS: We conducted a mixed-methods systematic review of published literature using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search was conducted in MEDLINE, EMBASE, CINAHL, Health Business Elite and Scopus. We adopted a convergent approach to synthesis and integration. Identified intervention and staff outcomes were categorised thematically and combined with available data on measures and effects. RESULTS: We identified 42 articles for inclusion. Safety culture outcomes were most prominent under the themes of leadership and teamwork. Specific benefits for staff included increased stress recognition and job satisfaction, reduced emotional exhaustion, burnout and turnover, and improvements to working conditions. Effects were documented for interventions with longer time scales, strong institutional support and comprehensive theory-informed designs situated within specific units. DISCUSSION: This review contributes to international evidence on how interventions to improve safety culture may benefit hospital staff and how they can be designed and implemented. A focus on staff outcomes includes staff perceptions and behaviours as part of a safety culture and staff experiences resulting from a safety culture. The results generated by a small number of articles varied in quality and effect, and the review focused only on hospital staff. There is merit in using the concept of safety culture as a lens to understand staff experience in a complex healthcare system.

Reliability of proxy reports on patient reported outcomes measures in stroke: An updated systematic review.

OBJECTIVES: With the rising global burden of stroke-related morbidity, and increased focus on patient-centered healthcare, patient reported outcome measures (PROMs) are increasingly used to inform healthcare decision-making. Some stroke patients with cognitive or motor impairments are unable to respond to PROMs, so proxies may respond on their behalf; the reliability of which remains unclear. The aim of the study is to update a 2010 systematic review to investigate the inter-rater reliability of proxy respondents answering PROMs for stroke patients. MATERIALS AND METHODS: Studies on the reliability of proxy respondents in stroke were searched within CINAHL, Embase, PsycInfo, and WoS databases (01/07/22, 08/07/22). Fifteen studies were included for review. ICC and k-statistic were extracted for PROMs scales and categorized as poor (0.80). Bias was assessed using the CCAT. RESULTS: Five studies reported PROMs with inter-rater reliability scores ranging from 0.80. Two studies reported activities of daily living (ADLs) scores ranging from 0.41 to 0.80 and 8 studies reported quality of life (QoL) measures with scores ranging from 0.80. Subcategories of these scales included physical (ICC/k-statistic 0.41- >0.8), cognitive (ICC/k-statistic 0.40-0.80), communication (ICC/k-statistic <0.4-0.80,) and psychological (ICC/k-statistic <0.40-0.60) measures. CONCLUSIONS: Proxy respondents are reliable sources for PROM reports on physical domains in ADLs, PROMs and QoL scales. Proxy reports for measures of communication and psychological domains had greater variability in reliability scores, ranging from poor to substantial; hence, caution should be applied when interpreting proxy reports for these domains.

A systematic review of the impact of compression therapy on quality of life and pain among people with a venous leg ulcer.

AIM: To gain a greater understanding of how compression therapy affects quality of life, this systematic review appraised existing published studies measuring the impact of compression therapy on health quality of life (HRQoL), and pain, among people with venous leg ulcers (VLU). METHOD: Five databases were searched, and two authors extracted data and appraised the quality of selected papers using the RevMan risk of bias tool. Due to heterogeneity in the types of compression and instruments used to evaluate HRQoL, meta-analysis was not appropriate; thus, a narrative synthesis of findings was undertaken. RESULTS: Ten studies were included, 9 RCTs and one before-after study. The studies employed nine different HRQoL tools to measure the impact of a variety of compression therapy systems, with or without an additional exercise programme, versus other compression systems or usual care, and the results are mixed. With the use of the Cardiff Cardiff Wound Impact Schedule, the SF-8 and the SF-12, study authors found no differences in QoL scores between the study groups. This is similar to one study using QUALYs (Iglesias et al., 2004). Conversely, for studies using EuroQol-5D, VEINES-QOL, SF-36 and CIVIQ-20 differences in QoL scores between the study groups were noted, in favour of the study intervention groups. Two further studies using QUALYs found results that favoured a two-layer cohesive compression bandage and the TLCCB group, respectively. Results for the five studies that assessed pain are also mixed, with one study finding no difference between study groups, one finding that pain increased over the study period and three studies finding that pain reduced in the intervention groups. All studies were assessed as being at risk of bias in one or more domains. CONCLUSION: Results were varied, reflecting uncertainty in determining the impact of compression therapy on quality of life and pain among people with a venous leg ulcer. The heterogeneity of the compression systems and the measures used to evaluate HRQoL make it a challenge to interpret the overall evidence. Further studies should strive for homogeneity in design, interventions and comparators to enhance both internal and external validity.

Assessing the healthcare costs associated with venous leg ulcer compression bandages - A scoping review.

AIM: To determine the monetary costs identified in economic evaluations of treatment with compression bandages among adults with venous leg ulcers (VLU). METHOD: A scoping review of existing publications was conducted in February 2023. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. RESULTS: Ten studies met the inclusion criteria. To place the costs of treatment into context, these are reported in conjunction with the healing rates. Three comparisons were made: 1.4 layer compression versus no compression (3 studies). One study reported that 4 layer compression was more expensive than usual care (£804.03 vs £681.04, respectively), while the 2 other studies reported the converse (£145 vs £162, respectively) and all costs (£116.87 vs £240.28 respectively). Within the three studies, the odds of healing were statistically significantly greater with 4 layer bandaging (OR: 2.20; 95% CI: 1.54-3.15; p = 0.001).; 2.4 layer compression versus other compression (6 studies). For the three studies reporting the mean costs per patient associated with treatment (bandages alone), over the treatment period, analysis identified a mean difference (MD) in costs for 4 layer vs comparator 1 (2 layer compression, short-stretch compression, 2 layer compression hosiery, 2 layer cohesive compression, 2 layer compression) of -41.60 (95% CI: 91.40 to 8.20; p = 0.10). The OR of healing for 4 layer compression vs comparator 1 (2 layer compression, short-stretch compression, 2 layer compression hosiery, 2 layer cohesive compression, 2 layer compression) is: 0.70 (95% CI: 0.57-0.85; p = 0.004). For 4 layer vs comparator 2 (2 layer compression) the MD is: 14.00 (95% CI: 53.66 to -25.66; p < 0.49). The OR of healing for 4 layer compression vs comparator 2 (2 layer compression) is: 3.26 (95% CI: 2.54-4.18; p < 0.00001). For comparator 1 (2 layer compression, short-stretch compression, 2 layer compression hosiery, 2 layer cohesive compression, 2 layer compression) vs comparator 2 (2 layer compression) the MD in costs is: 55.60 (95% CI: 95.26 to -15.94; p = 0.006). The OR of healing with Comparator 1 (2 layer compression, short-stretch compression, 2 layer compression hosiery, 2 layer cohesive compression, 2 layer compression) is: 5.03 (95% CI:4.10-6.17; p < 0.00001). Three studies presented the mean annual costs per patient associated with treatment (all costs). The MD is 172 (150-194; p = 0.401), indicating no statistically significant difference in costs between the groups. All studies showed faster healing rates in the 4 layer study groups. 3. Compression wrap versus inelastic bandage (one study). Compression wrap was less expensive than inelastic bandage (£201 vs £335, respectively) with more wounds healing in the compression wrap group (78.8%, n = 26/33; 69.7%, n = 23/33). CONCLUSION: The results for the analysis of costs varied across the included studies. As with the primary outcome, the results indicated that the costs of compression therapy are inconsistent. Given the methodological heterogeneity among studies, future studies in this area are needed and these should use specific methodological guidelines to generate high-quality health economic studies.

A meta-review of the impact of compression therapy on venous leg ulcer healing.

This meta-review aimed to appraise and synthesise findings from existing systematic reviews that measured the impact of compression therapy on venous leg ulcers healing. We searched five databases to identify potential papers; three authors extracted data, and a fourth author adjudicated the findings. The AMSTAR-2 tool was used for quality appraisal and the certainty of the evidence was appraised using GRADEpro. Data analysis was undertaken using RevMan. We identified 12 systematic reviews published between 1997 and 2021. AMSTAR-2 assessment identified three as high quality, five as moderate quality, and four as low quality. Seven comparisons were reported, with a meta-analysis undertaken for five of these comparisons: compression vs no compression (risk ratio [RR]: 1.55; 95% confidence interval [CI] 1.34-1.78; P < .00001; moderate-certainty evidence); elastic compression vs inelastic compression (RR: 1.02; 95% CI: 0.96-1.08; P < .61 moderate-certainty evidence); four layer vs

Hydrocarbon-Based Statistical Copolymers Outperform Block Copolymers for Stabilization of Ethanol-Water Foams.

Well-defined block copolymers have been widely used as emulsifiers, stabilizers, and dispersants in the chemical industry for at least 50 years. In contrast, nature employs amphiphilic proteins as polymeric surfactants whereby the spatial distribution of hydrophilic and hydrophobic amino acids within the polypeptide chains is optimized for surface activity. Herein, we report that polydisperse statistical copolymers prepared by conventional free-radical copolymerization can provide superior foaming performance compared to the analogous diblock copolymers. A series of predominantly (meth)acrylic comonomers are screened to identify optimal surface activity for foam stabilization of aqueous ethanol solutions. In particular, all-acrylic statistical copolymers comprising trimethylhexyl acrylate and poly(ethylene glycol) acrylate, P(TMHA-stat-PEGA), confer strong foamability and also lower the surface tension of a range of ethanol-water mixtures to a greater extent than the analogous block copolymers. For ethanol-rich hand sanitizer formulations, foam stabilization is normally achieved using environmentally persistent silicone-based copolymers or fluorinated surfactants. Herein, the best-performing fully hydrocarbon-based copolymer surfactants effectively stabilize ethanol-rich foams by a mechanism that resembles that of naturally-occurring proteins. This ability to reduce the surface tension of low-surface-energy liquids suggests a wide range of potential commercial applications.

Psychiatric nurse's perceptions of their interactions with people who hear voices: A qualitative systematic review and thematic analysis.

WHAT IS KNOWN ON THE SUBJECT?: There is no qualitative systematic review of nurses' perceptions of their interactions with people hearing voices. There are some studies exploring the interventions provided by community psychiatric nurses to people hearing voices; these give a sense of what interactions may contain. WHAT THE PAPER ADDS TO THE EXISTING KNOWLEDGE?: Nurses across both community and inpatient mental healthcare settings feel uncertain about how to interact with people hearing voices, sometimes feeling like they can do little to help. Their interactions are affected by the workplace culture, education and training and concern for their own safety. Nurses rely on a therapeutic relationship for all interactions. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: This is an under investigated area of mental healthcare. None the less this qualitative systematic review highlights that nurses are unclear about how to interact with service users hearing voices with the resultant outcome that service users in great distress may only be receiving minimal benefit from their interactions with the nurses caring for them. ABSTRACT: Aims and Objectives The aim of this qualitative systematic review and thematic analysis was to identify and synthesize results from studies that explored psychiatric nurses' perceptions of their interactions with service users experiencing auditory hallucinations (hearing voices). Method Qualitative systematic review and thematic analysis. Results Five studies that met the inclusion criteria were identified. Nurses reported that they felt uncertain about what to do for service users hearing voices, struggled to have interactions with voice hearers, but greatly valued the therapeutic relationship with service users. Nurses also reported that they required more education and training on how to interact effectively with people hearing voices. Finally, various workplace challenges were identified as an important factor mediating nurse interaction with service users hearing voices. Discussion Existing evidence shows that nurses lack clarity about how they can interact effectively and in a way that helps service users who are hearing voices. Significant barriers that they must overcome in order to be more certain of their role in caring for people hearing voices are difficult to engage service users and workplace challenges that were not conducive to helpful interactions and conversations. Implications for Practice Nurses caring for people hearing voices require more and better education and training with a view to them becoming more confident and competent when interacting with this service user group. Furthermore, healthy workplace cultures and maintaining a safe environment are necessary for effective caring interactions with people hearing voices.

'What effect do safety culture interventions have on health care workers in hospital settings?' A systematic review of the international literature.

Introduction: Interventions designed to improve safety culture in hospitals foster organisational environments that prevent patient safety events and support organisational and staff learning when events do occur. A safety culture supports the required health workforce behaviours and norms that enable safe patient care, and the well-being of patients and staff. The impact of safety culture interventions on staff perceptions of safety culture and patient outcomes has been established. To-date, however, there is no common understanding of what staff outcomes are associated with interventions to improve safety culture and what staff outcomes should be measured. Objectives: The study seeks to examine the effect of safety culture interventions on staff in hospital settings, globally. Methods and Analysis: A mixed methods systematic review will be conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches will be conducted using the electronic databases of MEDLINE, EMBASE, CINAHL, Health Business Elite, and Scopus. Returns will be screened in Covidence according to inclusion and exclusion criteria. The mixed-methods appraisal tool (MMAT) will be used as a quality assessment tool. The Cochrane Collaboration's tool for assessing risk of bias in randomised trials and non-randomised studies of interventions will be employed to verify bias. Synthesis will follow the Joanna Briggs Institute methodological guidance for mixed methods reviews, which recommends a convergent approach to synthesis and integration. Discussion: This systematic review will contribute to the international evidence on how interventions to improve safety culture may support staff outcomes and how such interventions may be appropriately designed and implemented.

Proficiency-based progression training: an 'end to end' model for decreasing error applied to achievement of effective epidural analgesia during labour: a randomised control study.

BACKGROUND: Training procedural skills using proficiency-based progression (PBP) methodology has consistently resulted in error reduction. We hypothesised that implementation of metric-based PBP training and a valid assessment tool would decrease the failure rate of epidural analgesia during labour when compared to standard simulation-based training. METHODS: Detailed, procedure-specific metrics for labour epidural catheter placement were developed based on carefully elicited expert input. Proficiency was defined using criteria derived from clinical performance of experienced practitioners. A PBP curriculum was developed to train medical personnel on these specific metrics and to eliminate errors in a simulation environment.Seventeen novice anaesthetic trainees were randomly allocated to undergo PBP training (Group P) or simulation only training (Group S). Following training, data from the first 10 labour epidurals performed by each participant were recorded. The primary outcome measure was epidural failure rate. RESULTS: A total of 74 metrics were developed and validated. The inter-rater reliability (IRR) of the derived assessment tool was 0.88. Of 17 trainees recruited, eight were randomly allocated to group S and six to group P (three trainees did not complete the study). Data from 140 clinical procedures were collected. The incidence of epidural failure was reduced by 54% with PBP training (28.7% in Group S vs 13.3% in Group P, absolute risk reduction 15.4% with 95% CI 2% to 28.8%, p=0.04). CONCLUSION: Procedure-specific metrics developed for labour epidural catheter placement discriminated the performance of experts and novices with an IRR of 0.88. Proficiency-based progression training resulted in a lower incidence of epidural failure compared to simulation only training. TRIAL REGISTRATION NUMBER: NCT02179879. NCT02185079; Post-results.

Silver engineered nanoparticles in freshwater systems - Likely fate and behaviour through natural attenuation processes.

Growth in the nanotechnology sector is likely introducing unnatural formations of materials on the nanoscale (10-9m) to the environment. Disposal and degradation of products incorporating engineered nanomaterials (ENMs) are likely being released into natural aquatic systems un-intentionally primarily via waste water effluents. The fate and behaviour of metallic based nanoparticles (NPs) such as silver (Ag) in aquatic waters is complex with high levels of variability and uncertainty. In-situ physical, biological and chemical (natural attenuation) processes are likely to influence ENM fate and behaviour in freshwater systems. Surfaced functionalized particles may inhibit or limit environmental transformations which influence particle aggregation, mobility, dissolution and eco-toxic potential. This paper focuses on ENM characteristics and the influence of physical, chemical and biological processes occurring in aquatic systems that are likely to impact metallic ENMs fate. A focus on silver NPs (while for comparison, reporting about other metallic ENMs as appropriate) released to aquatic systems is discussed relating to their likely fate and behaviour in this dynamic and complex environment. This paper further highlights the need for specific risk assessment approaches for metallic ENMs and puts this into context with regard to informing environmental policy and potential NP influence on environmental/human health.

Measuring Nanoparticle Attachment Efficiency in Complex Systems.

As process-based environmental fate and transport models for engineered nanoparticles are developed, there is a need for relevant and reliable measures of nanoparticle behavior. The affinity of nanoparticles for various surfaces (α) is one such measure. Measurements of the affinity of nanoparticles obtained by flowing particles through a porous medium are constrained by the types of materials or exposure scenarios that can be configured into such column studies. Utilizing glass beads and kaolinite as model collector surfaces, we evaluate a previously developed mixing method for measuring nanoparticle attachment to environmental surfaces, and validate this method with an equivalent static column system over a range of organic matter concentrations and ionic strengths. We found that, while both impacted heteroaggregation rates in a predictable manner when varied individually, neither dominated when both parameters were varied. The theory behind observed nanoparticle heteroaggregation rates (αßB) to background particles in mixed systems is also experimentally validated, demonstrating both collision frequency (ß) and background particle concentration (B) to be independent for use in fate modeling. We further examined the effects of collector particle composition (kaolinite vs glass beads) and nanoparticle surface chemistry (PVP, citrate, or humic acid) on α, and found a strong dependence on both.

Nanoparticle Surface Affinity as a Predictor of Trophic Transfer.

Nanoscale materials, whether natural, engineered, or incidental, are increasingly acknowledged as important components in large, environmental systems with potential implications for environmental impact and human health. Mathematical models are a useful tool for handling the rapidly increasing complexity and diversity of these materials and their exposure routes. Presented here is a mathematical model of trophic transfer driven by nanomaterial surface affinity for environmental and biological surfaces, developed in tandem with an experimental functional assay for determining these surface affinities. We found that nanoparticle surface affinity is a strong predictor of uptake through predation in a simple food web consisting of the algae Chlorella vulgaris and daphnid Daphnia magna. The mass of nanoparticles internalized by D. magna through consuming nanomaterial-contaminated algae varied linearly with surface-attachment efficiency. Internalized quantities of gold nanoparticles in D. magna ranged from 8.3 to 23.6 ng/mg for nanoparticle preparations with surface-attachment efficiencies ranging from 0.07 to 1. This model, coupled with the functional-assay approach, may provide a useful screening tool for existing materials as well as a predictive model for their development.

Maximal acceptable torques of six highly repetitive hand-wrist motions for male industrial workers.

OBJECTIVE: The purpose of the study was to quantify maximum acceptable torques (MATs) in 16 healthy male industrial workers while performing six motions: screw driving clockwise with a 40 mm handle and a 39 mm yoke handle, flexion and extension with a pinch grip,ulnar deviation with a power grip (similar to knife cutting), and a handgrip task (similar to a pliers task). BACKGROUND: Psychophysical studies on repetitive motions of the wrist and hand were previously reported on women; however, it is not clear how men will psychophysically respond to similar motions. METHOD: A psychophysical methodology was used in which the participant adjusted the resistance on the handle. Repetition rates for these tasks were 15 and 25 per minute. Participants performed the tasks for 7 hours per day, 5 days per week, and for 12 days. Symptoms were recorded by the subjects at the end of each hour. RESULTS: The mean MATs ranged from 1.15 Nm to 1.88 Nm for screw driving, 2.26 Nm to 3.71 Nm for pinch flexion and extension, 3.88 Nm to 4.07 Nm for ulnar deviation, and 11.47 Nm to 13.98 Nm for the handgrip task. The higher the repetition rate, the lower the MAT. Depending on the type of task and repetition rate, these values represented 15% to 35% (median of 23%) of their maximum isometric torque. APPLICATION: Based on aforementioned findings, a table of MATs and derived acceptable forces for six tasks at different percentage capabilities of the male industrial populations is formulated.

A risk assessment framework for assessing metallic nanomaterials of environmental concern: aquatic exposure and behavior.

Nanomaterials are finding application in many different environmentally relevant products and processes due to enhanced catalytic, antimicrobial, and oxidative properties of materials at this scale. As the market share of nano-functionalized products increases, so too does the potential for environmental exposure and contamination. This study presents some exposure ranking methods that consider potential metallic nanomaterial surface water exposure and fate, due to nano-functionalized products, through a number of exposure pathways. These methods take into account the limited and disparate data currently available for metallic nanomaterials and apply variability and uncertainty principles, together with qualitative risk assessment principles, to develop a scientific ranking. Three exposure scenarios with three different nanomaterials were considered to demonstrate these assessment methods: photo-catalytic exterior paint (nano-scale TiO2), antimicrobial food packaging (nano-scale Ag), and particulate-reducing diesel fuel additives (nano-scale CeO2). Data and hypotheses from literature relating to metallic nanomaterial aquatic behavior (including the behavior of materials that may relate to nanomaterials in aquatic environments, e.g., metals, pesticides, surfactants) were used together with commercial nanomaterial characteristics and Irish natural aquatic environment characteristics to rank the potential concentrations, transport, and persistence behaviors within subjective categories. These methods, and the applied scenarios, reveal where data critical to estimating exposure and risk are lacking. As research into the behavior of metallic nanomaterials in different environments emerges, the influence of material and environmental characteristics on nanomaterial behavior within these exposure- and risk-ranking methods may be redefined on a quantitative basis.

Gender differences in psychophysically determined maximum acceptable weights and forces for industrial workers observed after twenty years.

PURPOSE: In the year 1991, manual materials handling guidelines were published by Liberty Mutual Research Institute for Safety. In these guidelines, maximum acceptable weights (MAWs) and forces (MAFs) for lifting, lowering, pushing, pulling, and carrying were derived from studies conducted in a 20 year span before the above publication date. The question is whether the present generation of workers has retained the same gender differences and absolute values in psychophysically determined MAWs and MAFs as those reflected in the guideline. METHODS: Twenty-four female industrial workers performed 20 variations of lifting, lowering, pushing, pulling, and carrying. A psychophysical methodology was used whereby the workers chose a workload they could sustain for 8 h without "straining themselves or without becoming unusually tired, weakened, overheated or out of breath." RESULTS: In females, MAWs of lifting, lowering, and carrying averaged 53% of the present-day male values, similar to the 55% in the guideline. MAFs of pushing and pulling were 83 and 86% of the present-day male values but slightly higher than the 73 and 78% in the guideline, respectively for initial and sustained forces. CONCLUSIONS: The similarity of gender differences between the guideline and the present findings was coupled with dramatic decreases in MAWs of lifting, lowering, and carrying. Such decreases may reflect a new psychophysical set point; however, considerations about adjusting existing guidelines on lifting, lowering, and carrying may not be appropriate until additional data from other sources inside and outside the US confirm the present findings.

Influence of three principles of pacing on the temporal organisation of work during cyclic assembly and disassembly tasks.

A study was conducted to investigate the influence of different approaches to arranging the pace and temporal organisation of repetitive assembly and disassembly tasks on both average performance and its variability and to compare assembly and disassembly times derived with psychophysical methods to a more traditional methods-time measurement (MTM) approach. The conditions studied were a traditional assembly line arrangement, where assemblies were started at a pace of 110 MTM (repeated on two occasions), a batch condition, where subjects were required to complete 36 assemblies within the total amount of time allowed at 110, MTM and a psychophysical condition, where subjects were allowed to choose their pace (repeated on two occasions). Overall, the results suggest that the mean time spent working in each cycle (the 'on-time') remained fairly constant across conditions, while the idle 'off-time' in between on-times was shorter and of less varied duration in the more autonomous batch and psychophysical conditions. During the second psychophysical (self-paced) condition, subjects completed a significantly higher number of assemblies than during the 110 MTM line condition. The higher pace was achieved through reduction in mean off-times and the potential implications for musculoskeletal risk are discussed. STATEMENT OF RELEVANCE: Higher levels of autonomy over work pace, which intuitively would be beneficial from an ergonomics standpoint, actually led to subjects selecting to organise work such that off-times (idle times) were reduced. In contrast, active 'on' times were not affected much by autonomy. These results point to a reason that piecework would be associated with increased risk for musculoskeletal disorders.

Gender comparison of psychophysical forces, cardiopulmonary, and muscle metabolic responses during a simulated cart pushing task.

The purpose was to compare psychophysiological responses between healthy male and female workers during dynamic pushing. Using a psychophysical approach, 27 participants chose an acceptable force that they could push over a 7.6m distance at a frequency of 1 push per min on a treadmill. On a separate day, cardiopulmonary (e.g., whole-body oxygen uptake, heart rate, ventilation volume) and muscle metabolic measurements (change in muscle blood volume [ΔtHb] and Tissue Oxygenation Index [TOI]) from the right and left gastrocnemius muscles were collected simultaneously while participants pushed the previously chosen acceptable force on the treadmill at a similar frequency and distance for 2h. Results showed no significant difference between men and women for integrated force exerted on the instrumented treadmill handle and cardiopulmonary responses. In contrast, women demonstrated 45.7% lower ΔtHb but 3.6% higher TOI in the gastrocnemius region as compared to men, suggesting a lower hemoglobin concentration in women and high venous oxygen saturation during pushing. When ΔtHb and TOI were corrected for both body mass and pushing force, the disparity in gender was retained, implying an increased muscle oxygen saturation per force development in women than men during pushing. In the left gastrocnemius region, ΔtHb was 60% lower and TOI was 5.7% higher in women than men, suggesting an uneven muscle loading during pushing. Overall, the gender similarity in cardiopulmonary responses versus disparity in muscle metabolic responses suggest the importance of evaluating human performance during physical work at both whole-body and localized muscle levels.

Ranking initial environmental and human health risk resulting from environmentally relevant nanomaterials.

As nanomaterials find increased application in commercial and industrial products and processes so too the potential for release of these novel materials into the environment increases. The characteristics of these materials also may result in novel toxicological actions related to their nanoscale, which will have implications on their ecotoxicological and toxicological limits of exposure and eventual regulation. A framework for nanomaterial risk assessment on regulatory, ecotoxicological and toxicological bases developed from recent exposure and toxicity studies is presented. The release of nanoscale TiO(2), Ag and CeO(2) to the atmosphere and surface waters is assessed against provisional toxicological bench mark doses (BMDs) and critical effect doses (CEDs) developed from best available data. Predicted levels of nanomaterial release to surface waters and the atmosphere resulted in regulatory risk rankings of moderate concern based on worst case provisional regulatory limits. Inhalation and ingestion risk rankings were of very low concern based on the provisional inhalation and ingestion toxicity BMDLs and CEDLs determined for the nanomaterials in question. More toxicological data is needed on nanoscale CeO(2) inhalation to develop a true dose response as in vitro cytotoxicity studies yielded an inhalation risk ranking of lower concern. The moderate to high ecotoxicological risk rankings posed by the release of nanoscale TiO(2) and Ag to surface waters highlights the need for guidance and restriction on the usage and disposal of commercial products containing nanomaterial. The risk rankings presented in this assessment give a first indication of the relative risks posed by the usage and release of these materials into the environment and indicate what materials require further investigation into their nano-specific toxicological actions. As more nano-relevant toxicity studies are published, end-points and risk levels related to nano-specific toxicity actions may be determined and the provisional BMDLs developed as part of this framework refined, resulting in more confident risk rankings.

Psychophysically determined forces of dynamic pushing for female industrial workers: Comparison of two apparatuses.

Using psychophysics, the maximum acceptable forces for pushing have been previously developed using a magnetic particle brake (MPB) treadmill at the Liberty Mutual Research Institute for Safety. The objective of this study was to investigate the reproducibility of maximum acceptable initial and sustained forces while performing a pushing task at a frequency of 1min(-1) both on a MPB treadmill and on a high-inertia pushcart. This is important because our pushing guidelines are used extensively as a ergonomic redesign strategy and we would like the information to be as applicable as possible to cart pushing. On two separate days, nineteen female industrial workers performed a 40-min MPB treadmill pushing task and a 2-hr pushcart task, in the context of a larger experiment. During pushing, the subjects were asked to select a workload they could sustain for 8h without "straining themselves or without becoming unusually tired, weakened, overheated or out of breath." The results demonstrated that maximum acceptable initial and sustained forces of pushing determined on the high inertia pushcart were 0.8% and 2.5% lower than the MPB treadmill. The results also show that the maximum acceptable sustained force of the MPB treadmill task was 0.5% higher than the maximum acceptable sustained force of Snook and Ciriello (1991). Overall, the findings confirm that the existing pushing data developed by the Liberty Mutual Research Institute for Safety still provides an accurate estimate of maximal acceptable forces for the selected combination of distance and frequency of push for female industrial workers.