Elemental carbon - An efficient method to measure occupational exposure from materials in the graphene family.

Graphene is a 2D-material with many useful properties such as flexibility, elasticity, and conductivity among others. Graphene could therefore become a material used in many occupational fields in the future, which can give rise to occupational exposure. Today, exposure is unknown, due to the lack of efficient measuring techniques for occupational exposure to graphene. Readily available screening techniques for air sampling and -analysis are either nonspecific or nonquantitative. Quantifying materials from the broad graphene family by an easy-to-use method is important for the large-scale industrial application of graphene, especially when for the safety of working environment. Graphene consists primarily of elemental carbon, and the present study evaluates the organic carbon/elemental carbon (OC/EC)-technique for exposure assessment. The purpose of this work is to evaluate the OC/EC analysis technique as an efficient and easy-to-use method for quantification of occupational exposure to graphene. Methods that can identify graphene would be preferable for screening, but they are time consuming and semi-quantitative and therefore not suited for quantitative work environment assessments. The OC/EC-technique is a thermal optical analysis (TOA), that quantitively determines the amount of and distinguishes between two different types of carbon, organic and elemental. The technique is standardised, well-established and among other things used for diesel exposure measurements (ref standard). OC/EC could therefore be a feasible measuring technique to quantitively determine occupational exposure to graphene. The present evaluation of the technique provides an analytical method that works quantitatively for graphene, graphene oxide and reduced graphene oxide. Interestingly, the TOA technique makes it possible to distinguish between the three graphene forms used in this study. The technique was tested in an industrial setting and the outcome suggests that the technique is an efficient monitoring technique to be used in combination with characterisation techniques like for example Raman spectroscopy, scanning electron microscopy and atomic force microscopy.

Delayed clearance of the pro-carcinogen benzo[a]pyrene in PLHC-1 cells when co-exposed to the antifungal drug clotrimazole and effects on the CYP1A biomarker.

Cytochrome P450 1 A (CYP1A) is a key enzyme in the metabolism of the polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (BaP) in animals, and a biomarker for environmental PAH exposure. The common antimycotic imidazole drug clotrimazole (CLO) has been detected in the aquatic environment and likely co-exists with BaP. Like BaP, CLO can bind to CYP1A enzymes and can act as a CYP1A inhibitor. Co-exposure of BaP with CLO significantly delayed BaP elimination in a fish liver cell line (PLHC-1). Intracellular BaP concentration was 2.4 times higher after 6 h in co-exposed cells, compared to cells exposed to BaP alone. Higher BaP concentrations in cells co-exposed to CLO positively correlated with CLO dose, indicating CLO-mediated delays in BaP clearance. After 24 h, BaP was undetectable irrespective of CLO co-exposure. In contrast, intracellular CLO concentrations remained constant over the 72 h experimental period. Co-exposure of BaP with CLO caused synergistic and time-dependent increases on the CYP1A biomarker both on CYP1A mRNA levels and on CYP1A enzyme activity, in accordance with an apparent delayed BaP elimination in the presence of CLO. These results indicate a toxicokinetic interaction between BaP and CLO on the CYP1A enzyme that delays metabolic clearance of BaP.

Surfactant protein A in particles in exhaled air and plasma.

Respiratory tract lining fluid (RTLF) is an important component of the lung epithelial barrier. Pathological changes in RTLF may cause increased permeability of the epithelial barrier, but changes within RTLF are difficult to assess non-invasively. The aim of this study was to explore if the use of the non-invasive measurement technique, Particles in Exhaled Air (PEx) and blood test were useful in assessing epithelial barrier, and if cigarette smoking affects the relationship. In a general population subcohort from the European Community Respiratory Health Survey III in Iceland (n = 112), we collected RTLF droplets using the PEx technique, in conjunction with blood samples and questionnaire data. We measured surfactant protein A (SP-A) in the collected plasma and PEx samples. Participants were defined as healthy if they did not currently have asthma, were non-smokers and had forced expiratory volume in one second ≥ 80% of predicted value. Of the 112 participants, 97 were healthy and 15 were current smokers. There was no correlation between plasma and PEx SP-A levels. However, the ratio of plasma to PEx SP-A was significantly higher in smokers compared to healthy subjects. The lack of correlation between PEx and plasma SP-A in healthy participants, indicates that SP-A in plasma does not diffuse freely over the lung epithelial barrier. However, the lung epithelial barrier may be injured by smoking, leading to diffusion of SP-A across the barrier into the bloodstream, causing an increased ratio of plasma to PEx SP-A.

Rationale and Design of a Novel Method to Assess the Usability of Body-Worn Absorbent Incontinence Care Products by Caregivers.

PURPOSE: The purpose of this study was to develop and test a new method to measure the usability of absorbent incontinence care products from the caregivers' perspective and to investigate if the method can be used to differentiate between product types in a product change. DESIGN: Process evaluation and validation study. SUBJECTS AND SETTING: Product developers and end users participated in designing the new method. Thereafter, professional caregivers acted as testers of the new method, ranking usability when performing absorbent product changes on patients in a simulated nursing home care environment, assisted by third-party research institute moderators. METHODS: Design and evaluation of a new method designed to assess the usability of body-worn absorbent incontinence care products for lay caregivers were completed. The evaluation included formative and summative evaluations of effectiveness (product fit), efficiency (time and physical workload), and satisfaction. A person-centered approach aimed at including all subjects and settings to generate a single usability score for decision making and product benchmarking. Experienced caregivers changed 4 types of products: (1) disposable body-worn pads with mesh briefs (2-piece system); (2) disposable all-in-one briefs; (3) disposable, T-shaped, and belted brief; and (4) disposable pull-up pants on simulated patients in standing or lying position. Each product change was performed by 1 unassisted experienced caregiver. The probability of success as a score for each product type was calculated across the 4 metrics and reported with 95% confidence intervals (CIs). Descriptive and inferential statistics were developed assuming a binary statistical model, using the weighted scores from each of the factors. An overall usability score was calculated. RESULTS: The method we developed discriminated between usability of different product types. The overall score for the disposable pull-up product (90%; CI: 83%-97%) was better (P < .05) than for the disposable T-shaped brief (83%; CI: 77%-89%), the disposable brief (53%; CI: 45%-61%), and the disposable body-worn pad with mesh pant (61%; CI: 56%-66%) in standing patients. For lying patients, the overall score for the disposable T-shaped brief product (81%; CI: 73%-89% was better (P < .05) than the disposable brief (65%; CI: 45%-61%) and the disposable body-worn pads with mesh brief (62%; CI: 55%-69%). Reliability was evaluated quantitatively in terms of measurement uncertainties in the results. CONCLUSION: The method we described demonstrated differentiation of usability based on product type indicating concurrent validity. Further testing in diverse real-world care environments is needed to evaluate and confirm the validity and to assess reliability of this method in the research setting.

An Exploratory Study of Skin Problems Experienced by UK Nursing Home Residents Using Different Pad Designs.

PURPOSE: The primary aim of this study was to determine whether the severity of incontinence-associated dermatitis (IAD) among nursing home-based incontinence pad users varies between pad designs. A second aim was to examine the utility of a simple method for reporting skin health problems in which healthcare assistants were asked to record basic observational data at each pad change. STUDY DESIGN: Randomized, multiple crossover, observational, exploratory. SUBJECTS AND SETTING: Twenty-one men and 57 women using absorbent continence products to contain urinary and/or fecal incontinence were recruited from 10 nursing homes in London and the south of England. METHODS: A day-time variant and a night-time variant of each of the 4 main disposable pad designs on the market for moderate/heavy incontinence were tested: (1) insert pads with stretch pants; (2) 1-piece all-in-one diapers; (3) pull-up pants; and (4) belted/T-shape diapers. All pad variants for day-time use had an absorption capacity of 1900 mL ± 20% (measured using ISO 11948-1 International Standards Organization) while the capacity of night-time variants was 2400 mL ± 20%. Each resident used each of the 4 pad designs (day-time and night-time variants) for 2 weeks and the order of testing was randomized by nursing home. Skin health data were collected using 2 methods in parallel. Method 1 comprised visual observation by researchers (1 observation per pad design; 4 observations in total over 8 weeks). In method 2, healthcare assistants logged observational data on skin health at every pad change for the 8 weeks. The primary outcome variable was severity of the most severe skin problem noted by the researcher for each resident, and for each pad design (method 1). Descriptive data on skin care methods used in the nursing homes were also collected using short questionnaires and researcher observation. RESULTS: No significant differences in the severity or incidence of skin problems were found between observations using the 4 pad designs. However, a wide range of skin conditions was recorded that made classification difficult; the skin was often marked with creases from absorbent products, temporary marks, and pink/purple discoloration. We observed few cases of the severe erythema, rashes, and vesicles that are commonly used descriptors in previous skin tools. Nevertheless, the collected data reflect an abundance of skin problems that were difficult to categorize neatly. Researcher observations (method 1) showed that nearly all the residents (96%) had at least 1 IAD skin problem recorded over the 8-week period and 64% of residents had at least 1 problem that was rated as maximum severity. Healthcare assistants logged skin problems on 6.1% of pad changes. The discrepancy between researcher and healthcare assistant data appears to be largely due to healthcare assistants sometimes discounting low-grade IAD as normal for that population. CONCLUSION: Incontinence-associated dermatitis is common among nursing home residents who use incontinence pads, and it is often severe. No evidence was found that any design of pad was more likely than any others to be associated with skin problems. The method devised to enable healthcare assistants to record basic observational data on skin health in the diaper area at each pad change (Method 2) proved simple to use but still resulted in substantial underreporting of IAD, suggesting that further work is needed to develop a tool that more successfully encourages them to log and treat IAD problems.

Is it Feasible to Use Incontinence-Associated Dermatitis Assessment Tools in Routine Clinical Practice in the Long-term Care Setting?

PURPOSE: To investigate the feasibility of using incontinence-associated dermatitis (IAD) tools in routine clinical practice by asking nursing home staff (RNs and non-RN caregivers) and tissue viability specialty (TVS) nurses to evaluate 3 instruments and a 4-point severity scoring system for describing and grading IAD examples captured in photographs of skin underneath absorptive pads in nursing home patients. DESIGN: Feasibility study. SUBJECTS AND SETTING: Twelve female nursing home residents whose incontinence was managed with pads and who had previously been identified as experiencing IAD were recruited, along with 16 nursing home staff (6 RNs and 10 non-RNs) and 10 TVS nurses. METHODS: Weekly high-quality photographs were taken of the skin beneath absorptive pads of nursing home residents for 8 weeks yielding a library of 78 photographs. A subset of 10 representative photographs was chosen. The 16 nursing home staff and 10 TVS nurses were then asked to describe and grade the IAD in the 10 photographs using 3 IAD instruments and simple severity scoring system (SSS) developed for this study. Particular attention was paid to identifying any practical challenges staff encountered in conducting their task. RESULTS: The TVS nurses were able to use all 3 IAD instruments and the SSS and reported that they could incorporate them into their clinical practice with relative ease. Although the RNs were able to use the 3 instruments adequately with some initial assistance, they generally felt that they were too busy to complete them. By contrast, they reported that they found the SSS simple and quick enough to incorporate into their routine practice. The caregivers had difficulty with the text-based instruments, especially if English was not their first language, and they were only able to use the SSS. The caregivers' SSS scores for a given photograph varied more than TVS nurse scores, but the correlation between the mean TVS scores, which were operationally defined as the gold standard for purposes of this study, and the mean RN and caregiver scores (R = 0.811) were fairly high. CONCLUSIONS: Existing IAD instruments are too time-consuming and linguistically complex for use in routine clinical practice in nursing homes. We found that staff generally found the SSS easy to judge IAD severity based on pictures used in the study. This finding suggests that the SSS could be improved by adding reference photographs of skin illustrating each of the 4 points on the scale. Such an instrument could be designed and validated with an emphasis on integration into current clinical practice pathways.

Review of methods used for quantifying excess water in over-hydrated skin using evaporimetry.

BACKGROUND: Advances in diapers and skin barrier products are often aimed at reducing water penetration of the skin to prevent diaper dermatitis and evaporimetry has commonly been measured to quantify excess water in the skin. The aim of this study was to critically review the methods used to measure water vapour flux density (WVFD) using evaporimetry in order to identify a standardised methodology. METHODS: We used MEDLINE (1980-2008) and hand searching to identify published papers that used evaporimetry to measure WVFD when the skin has been exposed to water/saline/urine. We compared the papers with respect to subjects, sites, methods of hydrating the skin, the conditions of logging, timing and analysing the evaporimetry data. RESULTS: We identified 10 papers. Methods and techniques for measuring WVFD and analysing data varied considerably between studies and it was not possible to identify a standardised method. The main sources of error and variation are discussed. CONCLUSION: Little work has been carried out to establish the optimum methods and techniques needed to minimise variation in measurements of WVFD using evaporimetery. There is a need to develop more robust, standardised methods and to demonstrate their reliability for further work.

Solid-phase extraction and reverse-phase HPLC: application to study the urinary excretion pattern of benzophenone-3 and its metabolite 2,4-dihydroxybenzophenone in human urine.

BACKGROUND: Benzophenone-3 (BZ-3) is a common ultraviolet (UV) absorbing compound in sunscreens. It is the most bioavailable species of all UV-absorbing compounds after topical application and can be found in plasma and urine. OBJECTIVES: The aim of this study was to develop a reverse-phase high performance liquid chromatography (HPLC) method for determining the amounts BZ-3 and its metabolite 2,4-dihydroxybenzophenone (DHB) in human urine. The method had to be suitable for handling a large number of samples. It also had to be rapid and simple, but still sensitive, accurate and reproducible. The assay was applied to study the urinary excretion pattern after repeated whole-body applications of a commercial sunscreen, containing 4% BZ-3, to 25 healthy volunteers. METHODS: Each sample was analyzed with regard to both conjugated/non-conjugated BZ-3 and conjugated/non-conjugated DHB, since both BZ-3 and DHB are extensively conjugated in the body. Solid-phase extraction (SPE) with C8 columns was followed by reverse-phase HPLC. For separation a Genesis C18 column was used with an acethonitrile-water mobile phase and the UV-detector was set at 287 nm. RESULTS: The assay was linear r(2) > 0.99, with detection limits for BZ-3 and DHB of 0.01 micromol L(-1) and 0.16 micromol L(-1) respectively. Relative standard deviation (RSD) was less than 10% for BZ-3 and less than 13% for DHB. The excretion pattern varied among the human volunteers; we discerned different patterns among the individuals. CONCLUSIONS: The reverse-phase HPLC assay and extraction procedures developed are suitable for use when a large number of samples need to be analyzed and the method fulfilled our objectives. The differences in excretion pattern may be due to differences in enzyme activity but further studies, especially about genetic polymorphism, need to be performed to verify this finding.