Deep skin homogeneity and light diffusion: An accelerated Monte Carlo model for in vivo skin characterization and consumer perception

The appearance of healthy and youthful skin is related to many factors of the skin optical properties as perceived by our visual sense. The optics of light travelling through human tissues has been extensively investigated in the field of biomedical applications, including the experimental characterization and modelling of skin optics and the propagation of light such as lasers through the layers. This work presents an innovative approach to probe deep skin by means of spectrally and spatially resolved light diffusion in the different layers of skin. Dual hyperspectral measurements of the panellist's skin are performed in vivo on subjects to obtain reflectance and light diffusion spectra. Both are simultaneously fitted by a GPU-accelerated Monte Carlo model to obtain skin optical parameters as a function of depth. The results show a clear correlation between deep skin light diffusion at wavelengths above 590 nm and the subject age, which indicates a progressive degradation of skin homogeneity with age. The effect of this orange-red light diffusion background is to alter the colour tone of the skin. A skincare product is used to show that the warmer skin colour tone is clearly perceivable to consumers when evaluating facial images with and without the product. The product effect also correlates well with hyperspectral measurements. Lastly, this innovative approach demonstrates a first step in real-time skin characterization for consumers and opens the door to customized cosmetic solutions for individual needs.

Molecular characterization of cross-kingdom RNA interference in Botrytis cinerea by tomato small RNAs

Previous studies have suggested that plants can modulate gene expression in pathogenic fungi by producing small RNAs (sRNAs) that can be translocated into the fungus and mediate gene silencing, which may interfere with the infection mechanism of the intruder. We sequenced sRNAs and mRNAs in early phases of the Solanum lycopersicum (tomato)-Botrytis cinerea interaction and examined the potential of plant sRNAs to silence their predicted mRNA targets in the fungus. Almost a million unique plant sRNAs were identified that could potentially target 97% of all fungal genes. We selected three fungal genes for detailed RT-qPCR analysis of the correlation between the abundance of specific plant sRNAs and their target mRNAs in the fungus. The fungal Bcspl1 gene, which had been reported to be important for the fungal virulence, showed transient down-regulation around 20 hours post inoculation and contained a unique target site for a single plant sRNA that was present at high levels. In order to study the functionality of this plant sRNA in reducing the Bcspl1 transcript level, we generated a fungal mutant that contained a 5-nucleotide substitution that would abolish the interaction between the transcript and the sRNA without changing the encoded protein sequence. The level of the mutant Bcspl1 transcript showed a transient decrease similar to wild type transcript, indicating that the tomato sRNA was not responsible for the downregulation of the Bcspl1 transcript. The virulence of the Bcspl1 target site mutant was identical to the wild type fungus.

A thousand-genome panel retraces the global spread and adaptation of a major fungal crop pathogen

Human activity impacts the evolutionary trajectories of many species worldwide. Global trade of agricultural goods contributes to the dispersal of pathogens reshaping their genetic makeup and providing opportunities for virulence gains. Understanding how pathogens surmount control strategies and cope with new climates is crucial to predicting the future impact of crop pathogens. Here, we address this by assembling a global thousand-genome panel of Zymoseptoria tritici, a major fungal pathogen of wheat reported in all production areas worldwide. We identify the global invasion routes and ongoing genetic exchange of the pathogen among wheat-growing regions. We find that the global expansion was accompanied by increased activity of transposable elements and weakened genomic defenses. Finally, we find significant standing variation for adaptation to new climates encountered during the global spread. Our work shows how large population genomic panels enable deep insights into the evolutionary trajectory of a major crop pathogen.

Molecular characterization reveals no functional evidence for naturally occurring cross-kingdom RNA interference in the early stages of Botrytis cinerea-tomato interaction

Plant immune responses are triggered during the interaction with pathogens. The fungus Botrytis cinerea has previously been reported to use small RNAs (sRNAs) as effector molecules capable of interfering with the host immune response. Conversely, a host plant produces sRNAs that may interfere with the infection mechanism of an intruder. We used high-throughput sequencing to identify sRNAs produced by B. cinerea and Solanum lycopersicum (tomato) during early phases of interaction and to examine the expression of their predicted mRNA targets in the other organism. A total of 7042 B. cinerea sRNAs were predicted to target 3185 mRNAs in tomato. Of the predicted tomato target genes, 163 were indeed transcriptionally down-regulated during the early phase of infection. Several experiments were performed to study a causal relation between the production of B. cinerea sRNAs and the down-regulation of predicted target genes in tomato. We generated B. cinerea mutants in which a transposon region was deleted that is the source of c.10% of the fungal sRNAs. Furthermore, mutants were generated in which both Dicer-like genes (Bcdcl1 and Bcdcl2) were deleted and these displayed a >99% reduction of transposon-derived sRNA production. Neither of these mutants was significantly reduced in virulence on any plant species tested. Our results reveal no evidence for any detectable role of B. cinerea sRNAs in the virulence of the fungus.

Tackling microbial threats in agriculture with integrative imaging and computational approaches

Pathogens and pests are one of the major threats to agricultural productivity worldwide. For decades, targeted resistance breeding was used to create crop cultivars that resist pathogens and environmental stress while retaining yields. The often decade-long process of crossing, selection, and field trials to create a new cultivar is challenged by the rapid rise of pathogens overcoming resistance. Similarly, antimicrobial compounds can rapidly lose efficacy due to resistance evolution. Here, we review three major areas where computational, imaging and experimental approaches are revolutionizing the management of pathogen damage on crops. Recognizing and scoring plant diseases have dramatically improved through high-throughput imaging techniques applicable both under well-controlled greenhouse conditions and directly in the field. However, computer vision of complex disease phenotypes will require significant improvements. In parallel, experimental setups similar to high-throughput drug discovery screens make it possible to screen thousands of pathogen strains for variation in resistance and other relevant phenotypic traits. Confocal microscopy and fluorescence can capture rich phenotypic information across pathogen genotypes. Through genome-wide association mapping approaches, phenotypic data helps to unravel the genetic architecture of stress- and virulence-related traits accelerating resistance breeding. Finally, joint, large-scale screenings of trait variation in crops and pathogens can yield fundamental insights into how pathogens face trade-offs in the adaptation to resistant crop varieties. We discuss how future implementations of such innovative approaches in breeding and pathogen screening can lead to more durable disease control.

Hair surface quality: Laser scattering as a tool for characterizing the surface condition and deposits from shampoos and conditioners

OBJECTIVES

The hair surface condition underlies many visually perceived attributes such as shine, colour and the 3D perception of a curly hair style. Many factors can alter the hair surface such as cumulated cleansing/styling regimens or chemical treatments which can lead to degradation of the cuticle edges and surface. Similarly, pollutants, sebum, and shampoo/conditioners can build up on the hair surface which are also perceivable to an observer.

METHODS

The highly directive light of a laser is reflected and scattered by the surface of hair fibres into a circular pattern. The angular and spatial characteristics of this pattern reflect the hair geometry and the quality of the hair surface, i.e. the outer cuticle layer. Dark flat hair tresses were used to measure the impact of artificial sebum and shampoo/conditioner regimens on the cuticle surfaces. Also, longer single hair fibres from 4 volunteers were characterized for their surface changes from roots to tips, i.e. over the chronological age of the hair.

RESULTS

The laser scattering shows clear changes in specular reflection characteristics from treatments and allows for the extraction of the cuticle inclination angle with respect to the hair axis. Deep cleansing or clarifying shampoos do partially restore the cuticle angle by removing residues on the hair surface whereas more conditioning systems can lead to changes in specular reflection angle and scattering, especially for multiple cycles of shampoo + conditioner treatments. Lastly, changes in hair surface can be traced over time of hair age by this approach and are consistent with frequency and nature of hair treatments.

CONCLUSIONS

The method shows great potential for characterizing cleansing regimens in terms of their impact on the hair surface, either as single or multiple washes. Coverage or damage to the hair cuticles appears readily as an angle shift of the specular reflection whereas the quality of the surface topology has a direct impact on the angular width of the specular reflection thus affecting the shine band on a person's head. Hair ageing from root to tip can be quantified by laser scattering and correlates well with treatment events in time.

Effects of hair sprays on colour perception: a hyperspectral imaging approach to shine and chroma on heads

OBJECTIVES

Hair sprays apply fixative ingredients to provide hold to a hair style as well as weather resistance and optical properties such as shine. Generally, sprays distribute fine particles containing polymeric ingredients to form a thin film on the surface of hair. Different hair types require different strengths of the formed deposit on the hair surface. The present study shows how sprays also alter the visibility of the hair colour by altering the surface topology of the hair fibres.

METHODS

Hyperspectral imaging is used to map spectral characteristics of hair on mannequins and panelists over the curvature of heads. Spectral and spatial characteristics are measured before and after hair spray applications. The hair surface is imaged by SEM to visualize the degree of cuticle coverage. Finally, the perception of hair colour was evaluated on red-coloured mannequins by consumer questionnaire.

RESULTS

Hair sprays deposit different degrees of fixatives, which lead to a progressive leveling of the cuticle natural tilt angle with respect to the fibre axis. As a result, shine is progressively shifting towards the region of hair colour visibility and decreases the perceived colour of hair seen by consumers. Lighter sprays show thinner film formation on the hair surface and less of a shine shift than strong hold hair sprays.

CONCLUSIONS

Hair sprays are generally employed for hair style hold and weather resistance and considered without effect on hair colour. Our approach shows that spray-deposited films can affect colour perception by altering the microstructure of the hair surface. Thin films deposited on the hair fibre surface can partially fill gaps between cuticles, which reduces the cuticle natural angle. This partial erasure results in a angle shift of the shine regions towards the angle of internal reflection, thus decreasing the perceived hair colour regions as experienced by a group of consumers.

Water-resistant sunscreens for skin protection: an in vivo approach to the two sources of sunscreen failure to maintain UV protection on consumer skin

OBJECTIVES

The water resistance of sunscreen products has taken more importance for the UV protection of consumers involved in water activities and sports. The present work introduces a new in vivo approach to measure the water resistance of sunscreens on the actual skin of subjects, which can be easily applied to salt, chlorine and tap waters. The stress sources of sunscreen films on skin originate from two phenomena: high surface tension stress as the skin transits through the air/water interface and water diffusion into the film immersed in bulk water.

METHODS

The water resistance of sunscreen products is measured on the forearms of subjects by means of a new layered water bath approach that physically separates both stresses. Tape strips are subsequently taken and analysed for UV-A and UV-B optical densities via (1) imaging for remaining filters and (2) in vitro SPF absorption spectra.

RESULTS

Water-resistant sunscreens generally perform well when immersed in bulk water even subjected to agitation, but they show a wide range of performances when considering their behaviour at the air/water interface. The differences are more pronounced in salt water than tap water.

CONCLUSIONS

The results confirm 2 stress origins in sunscreen exposure to water: interfacial surface tension and bulk water diffusion. Polymers bring improvements to the resistance of sunscreens to bulk water but show wide latitude in performances when subject to the water surface tension stress. Globally, a higher loss of filters is observed in the UV-A than in the UV-B, which is attributed to more UV-A filter loss or degradation and thus resulting in a decreased protection in the UV-A.

A sunscreen-tanning compromise: 3D visualization of the actions of titanium dioxide particles and dihydroxyacetone on human epiderm

The self-tanning agent dihydroxyacetone (DHA) was applied to human skin samples, and its effect on light absorption was followed in time to study the DHA influence inside the different layers of skin. Application of DHA shows increased light absorption in the visible light region, as evidenced by skin tanning. The tanning effect is enhanced by UV irradiation and appears localized in the near-stratum corneum layer as revealed by depth analysis of the time signal. As a reference, application of an emulsion containing titanium dioxide particles shows clear surface stability and a screening of light penetration beyond the stratum corneum.

Pulsed photoacoustic spectroscopy applied to the diffusion of sunscreen chromophores in human skin: the weakly absorbent regime

Pulsed photoacoustic spectroscopy was used to study the penetration of sunscreen chromophores into human skin. This study focuses on basic solutions containing single typical filter molecules, as used in current sunscreens, dissolved in mineral oil. The pulsed form of the photoacoustic technique was preferred because it provides more detailed information on the filter distribution within the different layers of human skin. A new methodology provides better insight into the diffusion process through signal analysis in the time and frequency domains, allowing for global and depth-related characterization. The penetration of the chromophore influences the response signal by inducing changes in the optical and thermal properties at different depths within the medium. The light scattering effect of titanium dioxide was demonstrated by the same technique.

Pulsed photoacoustic study of the diffusion of chromophores in human skin

The technique of pulsed photoacoustic spectroscopy was used to investigate the diffusion of chromophores in human skin. The kinetic of diffusion has been studied for five solutions at different concentrations in a mixture of chromophores, as used in commercial sunscreens. In addition to the classical macroscopic interpretation of the diffusion process, a new method is shown to give more detailed information on chromophore presence at different depths in skin. For the first time, results are expressed in the frequency domain by means of the Fourier transform applied to the photoacoustic signal. The spectra are discussed versus the depth in skin samples and the time of diffusion kinetics. This new method of data analysis is shown to be very useful for understanding the influence of the internal structure of a medium on the penetration rate of chromophores into skin.

"Rubral" tremor after thalamic haemorrhage

Tremors in association with thalamic haemorrhage have been infrequently reported, and delayed rubral tremor as a complication of such an event is quite rare. We describe a patient with a combined resting-postural-kinetic tremor due a thalamic haemorrhage. Magnetic resonance imaging showed evidence of a subthalamic involvement but failed to reveal any mesencephalic lesion. Five years after the original stroke there was rapid and almost complete suppression of her abnormal movements, probably related to an ischaemic capsular lesion. Involuntary movements, which resemble rubral tremor, can be due to lesions upstream of the rubral and nigral outflow system.

[Iontophoresis of tenoxicam in the therapy of osteoarthrosis]

After a brief physiopathological research about iontophoresis applications, the authors examine this treatment by two drugs (Tenoxicam and acetylsalicylic acid) in a group of patients suffering from painful osteoarthritis. They came to the conclusion that the treatment is efficacious with both substances though realising a quicker analgesic result in the group treated with tenoxicam.

[Estimate of the dose of chlorinated pesticides consumed daily by the Italian population (1978-1984)]

This work reports an estimate of the doses of chlorinated pesticides taken with a total diet by the Italian population in the period 1978-84. Previous researches, carried out in 1971-72, had regarded both uncooked and cooked diets, ready for the consumption. It was found that the amount of the considered pesticides taken in total (HCB, gamma-BHC and total-BHC, Aldrin/Dieldrin, Heptachlor/Heptachlor-epoxide and DDT total-equivalent) calculated as a sum of the percentage of each acceptable daily intake (A.D.I.), at that time recommended was near the limit of acceptability (98.5% for cooked diets and 107.0% for uncooked diets). In addition it was found that nearly the 40% of the dose assumed in all came from milk and its derivates (butter, cheese). Then considering the contribution of milk and derivates to the amount of pollutants assumed with a total diet, a new evaluation has been done, with regard to the period 1978-84, i.e. after the prohibition of the use of these pesticides in Italy and in other industrialized countries. Then the data have been processed, with regard to 211 samples of foods (90 of milk, 45 of cheese, 76 butter) coming from determinations carried out by the Multizonal Laboratory of Hygiene and Prevention of Ferrara, Milano, Udine, Bolzano, Trento, Pescara and from the Institute of Hygiene of Rome University "La Sapienza" in the period mentioned. Furthermore, alimentary consumptions of milk, butter and cheese in 1978-84 have been evaluated, and amounts of chlorinated pesticides taken with these foods have been calculated. Finally the dose taken with these foods has been extrapolated to a total diet. It has come out that the doses (estimated) taken with the total diet have notably decreased between 1971-72 and 1978-84. An anomaly is yet represented by HCB: while the quantity taken with food has decreased from 1971-72 to 1978-84 (from 3.7 to 1.3 micrograms/man/day), the concentrations in human adipose tissues have increased (from 1.02 to 1.99 mg/Kg). It can reasonably mean that assumption of HCB is not prevalently alimentary, but that it is due to other factors of environmental contamination. The data of the doses of chlorinated pesticides taken have also been compared with the respective ADI indicated in 1971-72 and in 1978-84.

PCB and other organochlorine compounds in blood of women with or without miscarriage: a hypothesis of correlation

Polychlorobiphenyls (PCBs) have been shown to affect reproduction in experimental animals and in human beings following intoxication. The concentrations of PCBs and other organochlorine compounds were determined in blood samples from 120 women hospitalized for miscarriages and 120 full-term pregnancy controls. The average PCB hematic level (reported as Fenclor 54) was higher in women with miscarriages than in control women. No differences were detected as far as the hematic concentrations of hexachlorobenzene and DDT compounds were concerned. The reproductive history of each woman was assessed together with confounding variables on the phenomenon of miscarriage and the factors regarding environmental exposure and food intake. Food consumption did not indicate diet as the main source of PCB intake.

The use of tenax for the extraction of pesticides and polychlorinated biphenyls from water. II. Tests with artificially polluted and natural waters

The application of Tenax to the extraction of organic micro-pollutants such as pesticides and polychlorobiphenyls from waters has been studied, and it has been observed that also in the presence of other pollutants (oil, surface-active substances, etc.) the results obtained with an absorption column of Tenax-Celite are equivalent to those obtained with the continuous liquid-liquid extraction technique. For natural waters that contain solids in suspension that adsorb pesticides, it may be necessary to filter the water before extraction with Tenax and then to extract the suspended solids separately. Analyses of river and estuarine sea waters, filtered before extraction, showed the effectiveness of Tenax, and the extracts obtained for the pesticides analysis prove to be much less contaminated by interfering substances than the corresponding extracts obtained by the liquid-liquid technique.

Preliminary results on the use of Tenax for the extraction of pesticides and polynuclear aromatic hydrocarbons from surface and drinking waters for analytical purposes

The use of Tenax GC for the extraction of organic micro-pollutants such as pesticides and polynuclear aromatic hydrocarbons from water has been studied. In the absence of other contaminants and under conditions standardized at the time as optimal, the recovery of such substances is, on average, over 90%, both for the organochlorine and organophosphorus pesticides and for polynuclear aromatic hydrocarbons. Research into the effectiveness of extraction with Tenax from natural waters and water artificially contaminated with surfactants, fats and oils etc., in the laboratory is now being carried out.