Polysaccharide Composite Alginate-Pectin Hydrogels as a Basis for Developing Wound Healing Materials.

This article presents materials that highlight the bioengineering potential of polymeric systems of natural origin based on biodegradable polysaccharides, with applications in creating modern products for localized wound healing. Exploring the unique biological and physicochemical properties of polysaccharides offers a promising avenue for the atraumatic, controlled restoration of damaged tissues in extensive wounds. The study focused on alginate, pectin, and a hydrogel composed of their mixture in a 1:1 ratio. Atomic force microscopy data revealed that the two-component gel exhibits greater cohesion and is characterized by the presence of filament-like elements. The dynamic light scattering method indicated that this structural change results in a reduction in the damping of acoustic modes in the gel mixture compared to the component gels. Raman spectroscopy research on these gels revealed the emergence of new bonds between the components' molecules, contributing to the observed effects. The biocompatibility of the gels was evaluated using dental pulp stem cells, demonstrating that all the gels exhibit biocompatibility.

Multispectral Raman Differentiation of Malignant Skin Neoplasms In Vitro: Search for Specific Biomarkers and Optimal Wavelengths.

Confocal scanning Raman and photoluminescence (PL) microspectroscopy is a structure-sensitive optical method that allows the non-invasive analysis of biomarkers in the skin tissue. We used it to perform in vitro diagnostics of different malignant skin neoplasms at several excitation wavelengths (532, 785 and 1064 nm). Distinct spectral differences were noticed in the Raman spectra of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), compared with healthy skin. Our analysis of Raman/PL spectra at the different excitation wavelengths enabled us to propose two novel wavelength-independent spectral criteria (intensity ratios for 1302 cm-1 and 1445 cm-1 bands, 1745 cm-1 and 1445 cm-1 bands), related to the different vibrational "fingerprints" of cell membrane lipids as biomarkers, which was confirmed by the multivariate curve resolution (MCR) technique. These criteria allowed us to differentiate healthy skin from BCC and SCC with sensitivity and specificity higher than 95%, demonstrating high clinical importance in the differential diagnostics of skin tumors.

Life-history variation as a source of diversity for endemic white charr (Salmonidae) of the lower Kamchatka River.

Sympatric fish morphs diversifying in their feeding pattern in fresh waters typically implement alternative migratory tactics so that omnivores become migrants and specialists-residents. Charrs of the genus Salvelinus populating the lower Kamchatka River (Northeast Asia) are a rare example wherein two related sympatric morphs both implement a variety of life-history tactics in parallel. Here the authors analyse the ecological diversity in the endemic piscivorous "white" morph that exploits resources of the Kamchatka River in sympatry with the partially anadromous invertivorous "Dolly Varden" (DV) morph. Eco-morphological criteria allowed the authors to validate the morph identification. The white charr (WC) was found to subdivide into the small-sized (up to 1.6 kg) fish inhabiting the lacustrine part of the ecosystem and the large-sized (up to 3.4 kg) fish inhabiting the main river channel. The persistent spatial segregation of the sub-groups was confirmed by significant differences in the life span, muscle δ13 С signature and parasite load. According to contrasting patterns of strontium accumulation in otoliths, the riverine WC is represented by resident and semi-anadromous individuals. At the same time, the lack of microsatellite DNA differentiation and allometric nature of the morphometric discrepancy point to the intra-population source of the WC polymorphism. The authors suggest that WC diverged from DV as a result of feeding specialization on the threespine stickleback numerous in the ecosystem since the temporary flooding by marine waters in the middle Holocene. The modern stickleback division into local stocks following the ecosystem differentiation into a river, side lake and estuary resulted in the WC life-history split and ecological radiation.

Natural toxic impact and thyroid signalling interplay orchestrates riverine adaptive divergence of salmonid fish.

Adaptive radiation in fishes has been actively investigated over the last decades. Along with numerous well-studied cases of lacustrine radiation, some examples of riverine sympatric divergence have been recently discovered. In contrast to the lakes, the riverine conditions do not provide evident stability in the ecological gradients. Consequently, external factors triggering the radiation, as well as developmental mechanisms underpinning it, remain unclear. Herein, we present the comprehensive study of external and internal drivers of the riverine adaptive divergence of the salmonid fish Salvelinus malma. In the Kamchatka River, north-east Asia, this species splits in the reproductively isolated morphs that drastically differ in ecology and morphology: the benthivorous Dolly Varden (DV) and the piscivorous stone charr (SC). To understand why and how these morphs originated, we performed a series of field and experimental work, including common-garden rearing, comparative ontogenetic, physiological and endocrinological analyses, hormonal 'engineering' of phenotypes and acute toxicological tests. We revealed that the type of spawning ground acts as the decisive factor driving the radiation of S. malma. In contrast to DV spawning in the leaf krummholz zone, SC reproduces in the zone of coniferous forest, which litter has a toxic impact on developing fishes. SC enhances resistance to the toxicants via metabolism acceleration provided by the elevated thyroid hormone expenditure. These physiological changes lead to the multiple heterochronies resulting in a specific morphology and ecology of SC. Salvelinus malma represents a notable example of how the thyroid axis contributes to the generation of diverse phenotypic outcomes underlying the riverine sympatric divergence. Our findings, along with the paleoecology data concerning spruce forest distribution during the Pleistocene, provide an opportunity to reconstruct a scenario of S. malma divergence. Taken together, obtained results with the data of the role of thyroid hormones in the ontogeny and diversification of fishes contribute a resource to consider the thyroid axis as a prime director orchestrating the phenotypic plasticity promoting evolutionary diversification under the changing environmental conditions.

Raman scattering for dosimetry using GAFCHROMIC EBT3 radiochromic dosimetry film.

PURPOSE: Raman scattering spectra can be thought of as the "fingerprints" of the investigated material. The purpose of this work was to link the absorbed doses of irradiated radiochromic film at the micrometer level with changes in their Raman spectra. METHODS: Raman spectra of irradiated GAFCHROMIC EBT3 film with doses ranging from 0 to 40 Gy were acquired. The excitation wavelengths used in the experiments (457.9 and 647.1 nm) coincided with electronic transitions of the active layer of the film. The effect of resonance Raman scattering enhanced Raman peaks in the resonance region. Spectra were taken in the range of room temperature to around the temperature of liquid nitrogen (-190°C). RESULTS: The Raman peak intensity redistribution is shown for films with different absorbed doses. The ratio of intensities of the 1445 cm-1 band with respect to the 1330 cm-1 band increases with the increase in absorbed dose. This allows building a dose calibration curve for the film. CONCLUSION: The dose distribution of the irradiated film can be identified based on the intensity ratio of the 1445 and 1330 cm-1 bands by means of Raman mapping. This is a noninvasive and computerized readout method which provides micrometer resolution results for the film surface. This is beneficial in the use of radiochromic films as dosimeters for high-precision radiotherapies.