Evaluation of cytotoxicity and MRI contrast enhancement ability of Fe3O4@PLA-PEG iron oxide nanoparticles in vitro model

SPIONs are composed of Fe3O4 or gamma Fe2O3 cores and a biocompatible shell from Dextran, PLA, PEG, Chitosan, or PVA. SPIONs have many important applications in medicine and biology such as cell sorting, drug carrier, magnetic hyperthermia, and magnetic resonance imaging (MRI). This study aims to check the ability of copolymer PLA-PEG coated Fe3O4 ferromagnetic nanosystems (Fe3O4@PLA-PEG) produced for MRI application. The results showed that these nanoparticles had non-toxicity on BT-474 and Sarcoma 180 cell lines. Evaluation on T2 imaging mode revealed that Fe3O4@PLA-PEG nanoparticles were capable of enhancing the MRI image contrast in different conditions, including water, cell lysates solution, and even inside the cells. The report demonstrates that Fe3O4@PLA-PEG nanoparticles have a high potential application in MRI for clinical diagnosis.

INFLUENCE OF P-RADIATION ON PHYSICAL, CHEMICAL AND BIOLOGICAL SYSTEMS. RESULTS OF SOME SEARCH EXPERIMENTS

The paper presents search experiments of the dependence of the parameters of physical (alpha decay of the Pu-239 isotope), chemical (fluctuations in a water cell) and biological (male Wistar rats) systems on the direction of rotation of the Poynting vector. It was found that in the case of clockwise rotation of the Poynting vector, an increase in the rate of radioactive decay by about 2 % is observed in comparison with the case without exposure. There is also an effect on the parameters of fluctuations in the water cell. When rotated counterclockwise, no such change is observed. In the case of biological systems, reactions that depend on the direction of rotation of the Poynting vector are also observed.

Depigmenting potential of lichen extracts evaluated by in vitro and in vivo tests

Melanin is the main pigment of human skin, playing the primary role of protection from ultraviolet radiation. Alteration of the melanin production may lead to hyperpigmentation diseases, with both aesthetic and health consequences. Thus, suppressors of melanogenesis are considered useful tools for medical and cosmetic treatments. A great interest is focused on natural sources, aimed at finding safe and quantitatively available depigmenting substances. Lichens are thought to be possible sources of this kind of compounds, as the occurrence of many phenolic molecules suggests possible effects on phenolase enzymes involved in melanin synthesis, like tyrosinase. In this work, we used four lichen species, Cetraria islandica Ach., Flavoparmelia caperata Hale, Letharia vulpina (L.) Hue, and Parmotrema perlatum (Hudson) M. Choisy, to obtain extracts in solvents of increasing polarity, viz. chloroform, chloroform-methanol, methanol, and water. Cell-free, tyrosinase inhibition experiments showed highest inhibition for L. vulpina methanol extract, followed by C. islandica chloroform-methanol one. Comparable results for depigmenting activities were observed by means of in vitro and in vivo systems, such as MeWo melanoma cells and zebrafish larvae. Our study provides first evidence of depigmenting effects of lichen extracts, from tyrosinase inhibition to cell and in vivo models, suggesting that L. vulpina and C. islandica extracts deserve to be further studied for developing skin-whitening products.

Idioblasts as pathways for distributing water absorbed by leaf surfaces to the mesophyll in Capparis odoratissima

ABSTRACTCapparis odoratissima is a tree species native to semi-arid environments of the northern coast of South America where low soil water availability coexists with frequent nighttime fog. Previous work with this species demonstrated that C. odoratissima is able to use water absorbed through its leaves at night to enhance leaf hydration, photosynthesis, and growth.Here, we combine detailed anatomical evaluations of the leaves of C. odoratissima, with water and dye uptake experiments in the laboratory. We used immunolocalization of pectin and arabinogalactan protein epitopes to characterize the chemistry of foliar water uptake pathways.The abaxial surfaces of C. odoratissima leaves are covered with overlapping, multicellular peltate hairs, while the adaxial surfaces are glabrous but with star-shaped “structures” at regular intervals. Despite these differences in anatomy, both surfaces are able to absorb condensed water, but this ability is most significant on the upper surface. Rates of evaporative water loss from the upper surface, however, are coincident with cuticle conductance. Numerous idioblasts connect the adaxial leaf surface and the adaxial peltate hairs, which contain hygroscopic substances such as arabinogalactan proteins and pectins.The highly specialized anatomy of the leaves of C odoratissima fulfills the dual function of avoiding excessive water loss due to evaporation, while maintaining the ability to absorb liquid water. Cell-wall related hygroscopic compounds present in the peltate hairs and idioblasts create a network of microchannels that maintain leaf hydration and promote the uptake of aerial water.

Differences between hygroscopicity limit and cell wall saturation investigated by LF-NMR on Southern pine (Pinus spp.)

Low-field nuclear magnetic resonance (LF-NMR) was used to clarify the difference between the fiber saturation point (FSP) of Southern pine (Pinus spp.) determined at the hygroscopicity limit (HL) vs. cell wall saturation (CWS). The HL samples were conditioned at 100% relative humidity (RH) while the CWS samples were fully saturated with distilled water. Cell wall water was found to increase by around 10% in the CWS state. A possible explanation may be that the cell wall was further swollen under liquid saturation. The increase in water content located in the cell wall was determined using freezing-point depression. About 11% of the moisture content (MC) was found in cell wall nanopores with sizes ranging from 1.73 nm to 13.80 nm. The discrepancy between the HL and CWS values of the samples was attributed to freezable water in the nanopores of the matrix components and inter-microfibrils. In the drying process, wood shrinkage was further evaluated in the MC region corresponding to the discrepancy, where the tangential and radial dimensions changed slightly.

Counting water cells in bargraphs of compositions and set partitions

In this paper, we consider statistics on compositions and set partitions represented geometrically as bargraphs. By a water cell, we mean a unit square exterior to a bargraph that lies along a horizontal line between any two squares contained within the area subtended by the bargraph. That is, if a large amount of a liquid were poured onto the bargraph from above and allowed to drain freely, then the water cells are precisely those cells where the liquid would collect. In this paper, we count both compositions and set partitions according to the number of descents and water cells in their bargraph representations and determine generating function formulas for the joint distributions on the respective structures. Comparable generating functions that count non-crossing and non-nesting partitions are also found. Finally, we determine explicit formulas for the sign balance and for the first moment of the water cell statistic on set partitions, providing both algebraic and combinatorial proofs.