INVESTIGATING PHYSICAL PROPERTIES OF BIOPOLYMERS IN HAIR

Hair is of outmost importance for the human body. Hair is composed of 1–8% external hydrophobic lipid epidermis, 80–90% α-helix or β-sheet conformation of parallel polypeptide chains to form water-insoluble keratin, less than 3% melanin pigment, and 0.6–1.0% trace elements, 10–15% moisture (Figure 1) [1]. Keratin proteins are insoluble in water and play a protective role. They possess a heterogeneous morphology that classifies them to the fibrous structural proteins. We received samples of hair that had undergone treatment with a hair mask prepared by a cosmetic company (Figure 2). The samples were taken in different timelines (table 1) to assess not only the reconstruction of keratin induced by the cosmetic formulation but also the possibility of a long-term effect on the hai

Ecotoxicity of hallachrome, an unusual 1-2 anthraquinone excreted by the infaunal polychaete Halla parthenopeia: evidence for a chemical defence?

Polychaetes play a prominent role in marine systems, but little is known about their secondary metabolites compared with other benthic taxa. In the present study, we investigated the toxicity of hallachrome, an unusual 1-2 anthraquinone identified from the skin of some polychaetes, including the Mediterranean infaunal species Halla parthenopeia. Under stress conditions, this worm releases a harmful purple mucus, whose noxious compounds were still unknown. We hypothesized that hallachrome also occurs in the purple mucus, giving rise to its color and toxicity. Soon after the production of the purple exudate, H. parthenopeia also secretes a harmless, transparent mucus, which pushes away the toxic one, suggesting protective functions for the worm itself. LC-MS and H-1-NMR analyses confirmed the presence of the pigment hallachrome in the purple mucus. The average concentration of the pigment in the purple mucus was about 310 mg L-1. Ecotoxicological bioassays on representative species of bacteria, protozoans, rotifers, crustaceans (Artemia franciscana) and polychaetes (Dinophilus gyrociliatus) revealed its severe toxic effects: LC50/EC(50)values ranged from 0.11-5.67 mg L-1. Hallachrome showed higher toxicity for A. franciscana than other naturally occurring anthraquinones. Tests on encapsulated embryos of D. gyrociliatus evidenced the ability of a mucus layer to limit hallachrome diffusion, confirming the protective role of the transparent mucus. Given the information available on polychaetes anti-predator strategies, hallachrome cannot be considered a consumer deterrent. However its toxicity and wide range of activity suggest chemical defensive functions against potential competitors, parasites and/or pathogens

Ab initio insights into the interaction mechanisms between boron, nitrogen and oxygen doped diamond surfaces and water molecules

Diamond and diamond-like carbon coatings are used in many applications ranging from biomedicine to tribology. A wide range of dopants have been tested to modify the hydrophilicity of these surfaces, since this is central to their biocompatibility and tribological performance in aqueous environments. Despite the large number of experimental investigations, an atomistic understanding of the effects of different dopants on carbon film hydrophilicity is still lacking. In this study, we employ ab initio calculations to elucidate the effects of B, N, and O dopants in several mechanisms that could modify interactions with water molecules and thus hydrophilicity. These include the adsorption of intact water molecules on the surfaces, minimum energy pathways for water dissociation, and subsequent interactions of hydrogenated and hydroxylated surfaces with water molecules. We find that all of the dopants considered enhance hydrophilicity, but they do so through different means. Most notably, B dopants can spontaneously chemisorb intact water molecules and increase its interactions in H-bond networks

In situ study of soil processes in an oxisol-spodosol sequence of Amazonia (Brazil)

L'étude in situ de l'évolution d'échantillons de vermiculite et de résines à cations échangeables et kelates insérés dans le sol met en évidence les processsus pédogénétiques caractérisant une séquence de sols de la région de Manaus (Brésil

Imaging features of extraskeletal mesenchymal chondrosarcoma of the hand

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The impact of rumen-protected amino acids on the expression of key- genes involved in the innate immunity of dairy sheep

Rumen protected amino acids inclusion in ewes’ diets has been proposed to enhance their innate immunity. The objective of this work was to determine the impact of dietary supplementation with rumen-protected methionine or lysine, as well as with a combination of these amino acids in two different ratios, on the expression of selected key-genes (NLRs, MyD88, TRIF, MAPK-1, IRF-3, JunD, TRAF-3, IRF-5, IL-1α, IL-10, IKK-α, STAT-3 and HO-1). Thus, sixty Chios dairy ewes (Ovis aries) were assigned to one of the following five dietary treatments (12 animals/ treatment): A: basal diet consist of concentrates, wheat straw and alfalfa hay (control group); B: basal diet +6.0 g/head rumen-protected methionine; C: basal diet + 5.0 g/head rumen-protected lysine; D: basal diet +6.0 g/head rumen-protected methionine + 5.0 g/head rumen-protected lysine and E: basal diet +12.0 g/head rumen-protected methionine + 5.0 g/head rumen-protected lysine. The results revealed a significant downregulation of relative transcript level of the IL-1α gene in the neutrophils of C and in monocytes of D ewes compared with the control. Significantly lower mRNA transcript accumulation was also observed for the MyD88 gene in the neutrophils of ewes fed with lysine only (C). The mRNA relative expression levels of JunD gene were highly induced in the monocytes, while those of IL-10 and HO-1 genes were declined in the neutrophils of ewes fed with the C and D diets compared with the control. Lower transcript levels of STAT-3 gene were observed in the neutrophils of ewes fed with either C or with E diets in comparison with the control. In conclusion, our results suggest that the dietary supplementation of ewes with rumen-protected amino acids, down regulate the expression of some genes involved in the pro-inflammatory signalling

Defects drive the tribocharging strength of PTFE: An ab-initio study

If polytetrafluoroethylene (PTFE), commonly known as Teflon, is put into contact and rubbed against another material, almost surely it will be more effective than its counterpart in collecting negative charges. This simple, basic property is captured by the so called triboelectric series, where PTFE ranks extremely high, and that qualitatively orders materials in terms of their ability to electrostatically charge upon contact and rubbing. However, while classifying materials, the series does not provide an explanation of their triboelectric strength, besides a loose correlation with the workfunction. Indeed, despite being an extremely familiar process, known from centuries, tribocharging is still elusive and not fully understood. In this work we employ density functional theory to look for the origin of PTFE tribocharging strength. We study how charge transfers when pristine or defective PTFE is put in contact with different clean and oxidized metals. Our results show the important role played by defects in enhancing charge transfer. Interestingly and unexpectedly our results show that negatively charged chains are more stable than neutral ones, if slightly bent. Indeed deformations can be easily promoted in polymers as PTFE, especially in tribological contacts. These results suggest that, in designing materials in view of their triboelectric properties, the characteristics of their defects could be a performance determining factor

Prediction of chemical composition and peroxide value in unground pet foods by near-infrared spectroscopy

The massive development of the pet food industry in recent years has lead to the formulation of hundreds of canine and feline complete extruded foods with the objective of meeting both the needs of the animals and numerous demands from pet owners. In the meantime, highly variable raw material compositions and the industry's new production techniques oblige manufacturers to monitor all phases of the extrusion process closely in order to ensure the targeted composition and quality of the products. This study aimed at evaluating the potential of infrared technology (visible and near-infrared spectrophotometer; 570-1842 nm) in predicting the chemical composition and peroxide value (PV) of unground commercial extruded dog foods. Six hundred and forty-nine commercial extruded dog foods were collected. For each product, an unground aliquot was analysed by infrared instrument while a second aliquot was sent to a laboratory for proximate analysis and PV quantification. The wide range of extruded dog food typologies included in the study was responsible for the wide variability observed within each nutritional trait, especially crude fibre and ash. The mean value of the 208 pet foods sampled for PV quantification was 17.49 mEq O2/kg fat (min 2.2 and max 94.10 mEq O2/kg fat). The coefficients of determination in cross-validation of NIRS prediction models were 0.77, 0.97, 0.83, 0.86, 0.78 and 0.94 for moisture, crude protein, crude fat, crude fibre, ash and nitrogen-free extract (NFE) respectively. PV prediction was less precise, as demonstrated by the coefficient of determination in cross-validation (0.66). The results demonstrated the potential of NIRS in predicting chemical composition in unground samples, with lower accuracy for moisture and ash, while PV prediction models suggest use for screening purposes only

Sea surface height and geostrophic velocity variability in the California current system as observed from the TOPEX altimeter

Eight years (1994-2000) of data from the TOPEX/Poseidon satellite altimeter are used to investigate the variability of the sea surface height and geostrophic velocity of the California Current system. The TOPEX/Posiedon satellite measures SSH along an exact-repeat set of groundtracks with a 10-day repeat cycle. In the domain studied here (140° - 110°W, 24° - 50°N) the groundtrack separation ranges from 200-300 km, decreasing with increased latitude. Along-track resolution is 5.75 km. Variances of SSH and across-track geostrophic velocities are presented. The annual SSH and velocity variances show the envelope of high variance associated with the California Current as a C shaped region from the coast at 45°N south to an offshore limit of ~135°W between 35° - 40°N and then back toward shore south of the California Bight at 30°N. High values of velocity variance are O(400) cm²s⁻² at 38°N and 126°W. Seasonal variances describe the development of the California Current system. In spring (defined here as March-May) as the system begins to develop, higher velocity variance is seen near the coast. By summer the variance has increased and moved farther offshore, before peaking in fall. Winter shows the energy moving farther offshore as it weakens. The velocity variance is partitioned into within season and seasonal mean variances to understand the contribution of inter-annual differences to the variance. The within season variance dominates in summer and fall, while the seasonal mean variance contributes significantly in winter. The offshore transport of SSH and energy is investigated by constructing Hovmöller diagrams (time versus longitude) at different latitudes. The offshore propagation speeds are shown to compare well with theoretical Rossby wave speeds south of 35°N but to be larger by a up to factor of 1.5 north of 35°N. The seasonal development is also described by showing seasonal wavenumber spectra on four descending and four ascending groundtracks in the domain. As the CC system develops, wavenumber energy increases at 200-300 km wavelengths on groundtracks closest to the coast. This energy propagates offshore and weakens. At the offshore tracks the wavenumbers show weaker energies and shorter wavelengths (150-200 km)