Gloves use and possible barriers - an observational study with concluding questionnaire.

Aim: The basic assumption of this study was that the use of medical non-sterile gloves represents a barrier to correct hand hygiene behaviour. The aim of this study was to examine this assumption and detect reasons for possible incorrect behaviour. Accordingly, the hypothesis is that peri-glove compliance is lower than hand-disinfection compliance. Methods: The study involved the direct observation of the use of non-sterile, single-use medical gloves in three different wards of a university hospital. Nursing staff and physicians were observed. After the observation period, the observed persons received a custom-designed questionnaire in order to test their self-assessment, knowledge as well as structural conditions relating to the use of gloves. The results were evaluated and compared with the observation data. Results: All employees disinfected their hands in 18.6% of cases before and in 65% of cases after the use of non-sterile gloves. Gloves were changed in the event of the indication for hand disinfection/change of gloves in 27.5% of cases. When changing gloves, the employees disinfected their hands in 47.2% of cases. The respondents assessed themselves as being significantly better than the observations revealed. The respondents are aware of the rules about hand disinfection before and after the use of gloves. However, it was less commonly known that gloves are not an absolute barrier to the transmission of bacteria. Conclusion: Non-sterile single-use gloves seem to be a barrier to hand disinfection. Solutions must be found in order to improve peri-glove compliance, in particular with regard to hand disinfection before and during the wearing of gloves. Alongside the mere transfer of knowledge, the use of non-sterile gloves with regard to the current structural conditions in everyday clinical practice should be critically scrutinised, questioned, tested and developed for the users through precise instructions.

Two dimensional finite element modelling for dynamic water diffusion through stratum corneum.

Solvents penetration through in vivo human stratum corneum (SC) has always been an interesting research area for trans-dermal drug delivery studies, and the importance of intercellular routes (diffuse in between corneocytes) and transcellular routes (diffuse through corneocytes) during diffusion is often debatable. In this paper, we have developed a two dimensional finite element model to simulate the dynamic water diffusion through the SC. It is based on the brick-and-mortar model, with brick represents corneocytes and mortar represents lipids, respectively. It simulates the dynamic water diffusion process through the SC from pre-defined initial conditions and boundary conditions. Although the simulation is based on water diffusions, the principles can also be applied to the diffusions of other topical applied substances. The simulation results show that both intercellular routes and transcellular routes are important for water diffusion. Although intercellular routes have higher flux rates, most of the water still diffuse through transcellular routes because of the high cross area ratio of corneocytes and lipids. The diffusion water flux, or trans-epidermal water loss (TEWL), is reversely proportional to corneocyte size, i.e. the larger the corneocyte size, the lower the TEWL, and vice versa. There is also an effect of the SC thickness, external air conditions and diffusion coefficients on the water diffusion through SC on the resulting TEWL.

Mid-infrared in vivo depth-profiling of topical chemicals on skin.

BACKGROUND/PURPOSE: Thermal emission decay-Fourier transform infrared (TED-FTIR) spectroscopy is a non-contact and non-destructive analytical technique and was used in this study to detect the presence of external chemicals on human skin in vivo. The detection was possible due to the ability of the TED-FTIR technique to acquire the mid-infrared spectrum of the outmost layers (less than 10 microm) of Stratum Corneum (SC) and the ability to identify the absorption bands of the chemical. METHODS: As an illustration of such measurements, propylene glycol (PG) was applied on human stratum corneum and depth-resolved TED-FTIR spectra of the SC were measured to quantify the concentration of PG in deeper layers of SC. RESULTS: The mid-infrared spectrum of the surface 0.7 microm layer of skin had 50% contribution from SC and 50% from PG. At 3 h after application, the contribution of PG at the surface decreased to 7% as PG molecules diffused deeper into the skin and were lost at the surface. At a depth of 6 microm, the maximum concentration was 20% after 25 min after PG application. CONCLUSIONS: This work shows the feasibility of the TED-FTIR technique to detect the presence of chemicals on human SC in vivo and without contact, and for a wide range of other applications, such as detection of toxic chemicals used as warfare (vesicant agents like sulphur mustard and organophosphate nerve agents), pesticides, and other toxins on fruit and vegetable skins, water, or even other contaminated surfaces.

Spectral depth profiling of arbitrary surfaces by thermal emission decay-Fourier transform infrared spectroscopy.

We report a new spectroscopic technique that combines step-scanning Fourier transform infrared spectroscopy with opto-thermal transient emission radiometry (OTTER) in order to provide near-surface depth-resolved spectra in the range 700-1800 cm(-1). It works nondestructively, without contact, with samples of arbitrary shape and size, without requiring prior preparation. The depth of surface probed depends on the thermal diffusivity of the sample; for organic materials it is approximately 10 microm. With homogeneous samples, absolute absorption coefficients can be measured. With two-layered samples, the technique proved able to distinguish between the spectral properties of the top layer and the substrate and to estimate the thickness of the top layer. We present a theoretical analysis with the main design features of the instrumentation and software, together with studies of homogeneous and layered samples, to validate the methods and illustrate the potential of the technique for practical applications.