Polarized Raman microspectroscopy can reveal structural changes of peritumoral dermis in basal cell carcinoma

Polarized Raman microspectroscopy can provide precious information regarding the orientation and ordering of the molecules in a sample without staining or particular preparation. This technique is used for the first time on a human skin section to probe the molecular modifications of the surrounding dermis in superficial basal cell carcinoma. Spectra using polarized and conventional Raman microspectroscopies were recorded on dermis bordering either the tumor or healthy epidermis. Band areas and spectral decomposition on selected vibrations were computed. Significant differences in dermal collagen vibration bands are detected using both polarized and conventional micro-spectroscopies, but the spectral changes between tumor and healthy tissues are enhanced using polarized Raman microspectroscopy. The analysis of these spectral differences highlights structural modifications of the triple helix of collagen. We see polarized Raman microspectroscopy as a potential tool that could be implemented for clinical analyses to guide clinicians and surgeons in the treatment of aggressive skin cancers. The information obtainable could also help better elucidate the molecular mechanisms induced in basal cell carcinoma development.     

Influence of chromatic and lighting on the visual environment of the elderly: A critical literature review

The use of color and lighting as factors for adapting the housing of the elderly is tending to develop, in response to demographic data on the aging of the population and its impact on lifestyles. Adapting the environment for those over 60 years has become a national issue for public policy. So this article takes stock of the studies carried out on this issue. We have to review all the literature devoted to this subject, focusing on research products dealing with the color and light interaction in the indoor environment of seniors.     

Temperature stability of a pure metakaolin based K-geopolymer: Part 1. Variations in the amorphous mineral network

The thermal behavior of a model MK based K-geopolymer (Si/Al = 1.38 and K/Al = 0.68; obtained by alkaline activation of a very pure metakaolin) was investigated between room temperature and 1400°C in order to evaluate its potentiality for high-temperature applications. The purpose of our study was to monitor the behavior of a geopolymer during a temperature rise in order to better understand its variations with respect to temperature. The works from the present paper focus only variations in the internal structure of the mineral matrix. The results presented here show that the amorphous mineral matrix is preserved up to 900°C. The results also show that there is a densification of the internal structure of tetrahedral network during heating, due to changes in the Q³ environments in fully-connected Q⁴ for both silicates and aluminates. Thus, our work provides a new more precise vision of the 3D geopolymeric mineral matrix for which the silicoaluminous network is not exclusively composed of Q⁴ entities, contrary to what is frequently encountered in the literature before.     

Comparative Study of Different Milk Samples Preservation Procedures for Bacteriologic Examination

The control of pathogenic bacteria present in foods, as well as scientific data concerning their behavior, are closely linked to analytical methods used and the way they are implemented. To assess the capacity of the laboratories to conduct correctly microbiological analyses, national and international proficiency testing schemes are organized. To set up these inter-laboratory studies (ILS), it is necessary to prepare artificially contaminated samples, which contamination level is sufficiently stable regarding their transportation conditions to the participating laboratories. In this context, we tested several procedures to maintain the concentration of Listeria monocytogenes and coagulase-positive staphylococci in milk samples: freezing temperature and addition of bacteriostatic agents at refrigeration temperatures, such as nystatin, boric acid, sodium azide, the lactoperoxidase system, or a boric acid mixture. Through this study we selected preservation procedures, which could be used to stabilize the contamination level of artificially contaminated milk samples during transportation without preventing the growth of the target bacteria during the analysis and after the initial dilution step. Boric acid mixture and boric acid were found to be effective in stabilizing the contamination level of Staphylococcus aureus in milk samples, whereas freezing, a boric acid mixture, and boric acid were suitable for milk samples containing L. monocytogenes, depending on the samples’ contamination rate. An erratum to this article can be found at     

Who is the Expert? Integrated Urban Modeling and the Reconfiguration of Expertise

Much has been spoken and written about the rationalization and optimization of services and amenities in urban territories. In this context, there is increasing use of numerical modeling techniques addressing the design, selection and/or calibration of policy instruments. The question of the relations between appraisal tools and policymaking has been widely studied. However, few studies have specifically focused on the role of modeling in policymaking processes. Drawing on two case studies, this paper suggests a change in the nature of multi-expertise: neither conflicting nor cross-sectoral, we observed in both cases an interwoven configuration with a network of experts making use of integrated models. We call this configuration distributed expertise, arguing that it is a novel configuration and that its emergence is closely linked to the development of integrated modeling techniques. Other authors have discussed the idea that the growing need for new appraisal tools is linked with the proliferation of wicked policy problems. From our case studies we would conclude that the emergence of integrated modeling is not a response to complex problems but to complex systems of actors who need to reach a consensus on actions.     

Quantitative measurement of protein stability from unfolding equilibria monitored with the fluorescence maximum wavelength

The fluorescence of tryptophan is used as a signal to monitor the unfolding of proteins, in particular the intensity of fluorescence and the wavelength of its maximum lambda(max). The law of the signal is linear with respect to the concentrations of the reactants for the intensity but not for lambda(max). Consequently, the stability of a protein and its variation upon mutation cannot be deduced directly from measurements made with lambda(max). Here, we established a rigorous law of the signal for lambda(max). We then compared the stability DeltaG(H(2)O) and coefficient of cooperativity m for a two-state equilibrium of unfolding, monitored with lambda(max), when the rigorous and empirical linear laws of the signal are applied. The corrective terms involve the curvature of the emission spectra at their lambda(max) and can be determined experimentally. The rigorous and empirical values of the cooperativity coefficient m are equal within the experimental error for this parameter. In contrast, the rigorous and empirical values of the stability DeltaG(H(2)O) generally differ. However, they are equal within the experimental error if the curvatures of the spectra for the native and unfolded states are identical. We validated this analysis experimentally using domain 3 of the envelope glycoprotein of the dengue virus and the single-chain variable fragment (scFv) of antibody mAbD1.3, directed against lysozyme.     

Measurements of Chlorpyrifos Levels in Forager Bees and Comparison with Levels that Disrupt Honey Bee Odor-Mediated Learning Under Laboratory Conditions

Chlorpyrifos is an organophosphate pesticide used around the world to protect food crops against insects and mites. Despite guidelines for chlorpyrifos usage, including precautions to protect beneficial insects, such as honeybees from spray drift, this pesticide has been detected in bees in various countries, indicating that exposure still occurs. Here, we examined chlorpyrifos levels in bees collected from 17 locations in Otago, New Zealand, and compared doses of this pesticide that cause sub-lethal effects on learning performance under laboratory conditions with amounts of chlorpyrifos detected in the bees in the field. The pesticide was detected at 17 % of the sites sampled and in 12 % of the colonies examined. Amounts detected ranged from 35 to 286 pg.bee^?1, far below the LD₅₀ of ~100 ng.bee^?1. We detected no adverse effect of chlorpyrifos on aversive learning, but the formation and retrieval of appetitive olfactory memories was severely affected. Chlorpyrifos fed to bees in amounts several orders of magnitude lower than the LD₅₀, and also lower than levels detected in bees, was found to slow appetitive learning and reduce the specificity of memory recall. As learning and memory play a central role in the behavioral ecology and communication of foraging bees, chlorpyrifos, even in sublethal doses, may threaten the success and survival of this important insect pollinator.     

On the reliability of scrape-off layer ion temperature measurements by retarding field analyzers

The retarding field analyzer (RFA) is one of the only widely accepted diagnostics for measurements of ion temperature Ti in the tokamak scrape-off layer. In this paper we analyze some instrumental effects of the RFA and their influence on Ti measurements. It is shown that selective ion transmission through the RFA slit is responsible for an overestimation of Ti by less than 14%, even for a relatively thick slit plate. Therefore, thicker slit plates are preferable, since they reduce, e.g., the risk of melting during off-normal events, and the effect of positive space charge inside the cavity. The influence of the electron repelling grid, as well as misalignment of the slit with respect to the magnetic field on Ti measurements are negligible.