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Previous studies have demonstrated that skin vibration is an important factor affecting the roughness perception of fine textures. For coarse textures, the determining physical factor is much less clear and there are indications that this might be participant-dependent. In this paper, we focused on roughness perception of both coarse and fine textures of different materials (glass particle surfaces and sandpapers). We investigated the relationship between subjective roughness ratings and three physical parameters (skin vibration, friction coefficient, and particle size) within a group of 30 participants. Results of the glass particle surfaces showed both spatial information (particle size) and temporal information (skin vibration) had a high correlation with subjective roughness ratings. The former correlation was slightly but significantly higher than the latter. The results also indicated different weights of temporal information and spatial information for roughness ratings among participants. Roughness ratings of a different material (sandpaper versus glass particles) could be either larger, similar or smaller, indicating differences among individuals. The best way to describe our results is that in their perceptual evaluation of roughness, different individuals weight temporal information, spatial information, and other mechanical properties differently.

Bisphenol A (BPA) is an endocrine disrupting chemical used in a wide range of consumer products including photoactive dyes used in thermal paper. Recent studies have shown that dermal absorption of BPA can occur when handling these papers. Yet, regulatory agencies have largely dismissed thermal paper as a major source of BPA exposure. Exposure estimates provided by agencies such as the European Food Safety Authority (EFSA) are based on assumptions about how humans interact with this material, stating that ‘typical’ exposures for adults involve only one handling per day for short periods of time (30% of individuals hold thermal paper with more than three fingertips, and >60% allow the paper to touch their palm. Only 11% of the participants we observed were consistent with the EFSA model for time of contact and dermal surface area. Mathematical modeling based on handling times we measured and previously published transfer coefficients, concentrations of BPA in paper, and absorption factors indicate the most conservative estimated intake from handling thermal paper in this population is 51.1 ng/kg/day, similar to EFSA’s estimates of 59 ng/kg/day from dermal exposures. Less conservative estimates, using published data on concentrations in thermal paper and transfer rates to skin, indicate that exposures are likely significantly higher. Based on our observational data, we propose that the current models for estimating dermal BPA exposures are not consistent with normal human behavior and should be reevaluated.

Background Traditional methods of detecting Leishmania from cutaneous lesions involve invasive diagnostic procedures, such as scrapings, which cause discomfort, require technical expertise, and carry risks of invasive procedures. We compared the performance of 2 novel, molecular-based non-invasive methods for the diagnosis of cutaneous leishmaniasis (CL). Methods Consecutive patients presenting to the Leishmania Clinic at the Hospital Nacional Cayetano Heredia were enrolled. PCR was performed on filter paper lesion impressions (FPLIs), cytology brushes, and lancets for detection of Leishmania DNA. Smears from lesion scrapings and leishmanin skin test were also performed. Outcome measures were sensitivity and specificity. Composite reference standard was any 2 of 5 tests positive. Species identification was performed by PCR assays of positive specimens. Results Ninety patients with 129 lesions were enrolled, 117 of which fulfilled reference criteria for a diagnosis of CL. Of these 117 lesions, 113 were positive by PCR of lancets used for lesion scrapings versus 116 by PCR of FPLIs (p = 0.930) or 116 by PCR of cytology brushes (p = 0.930). Sensitivity and specificity of PCR on lancets were 96.6% [95% CI 93.3–99.9%] and 100%, respectively. Sensitivity and specificity of FPLI PCR were 99.1% [95% CI 97.4–100%] and 100%, respectively. Sensitivity and specificity of cytology brush PCR were 99.1% [95% CI 97.4–100%] and 100%, respectively. Giemsa-stained lesion smear and leishmanin skin test had inferior sensitivities at 47.9% [95% CI 38.9–57.0%] and 82.3% [95% CI 73.9–90.7%], respectively, compared to PCR of invasive or non-invasive specimens (p