The effect of physical crosslinking on dynamic mechanical properties of polycarbonate low molecular weight additive systems

Summary The studies of dynamic mechanical properties (torsional pendulum) of polycarbonate-low molecular weight additive (ester derivatives of Bisphenol A and di-buthyl phthalate) systems show that the decrease of their glass transition temperature depends on the nature of the additive. The effect is greater for additives acting as plasticizers at room temperature as compared to antiplasticizers.Presented at the 7th IUPAC Discussion Conference Polymer Networks, Karlovy Vary, CSSR, September 15–19, 1980     

Role of Endothelial Glucocorticoid Receptor in the Pathogenesis of Kidney Diseases

Glucocorticoids, as multifunctional hormones, are widely used in the treatment of various diseases including nephrological disorders. They are known to affect immunological cells, effectively treating many autoimmune and inflammatory processes. Furthermore, there is a growing body of evidence demonstrating the potent role of glucocorticoids in non-immune cells such as podocytes. Moreover, novel data show additional pathways and processes affected by glucocorticoids, such as the Wnt pathway or autophagy. The endothelium is currently considered as a key organ in the regulation of numerous kidney functions such as glomerular filtration, vascular tone and the regulation of inflammation and coagulation. In this review, we analyse the literature concerning the effects of endothelial glucocorticoid receptor signalling on kidney function in health and disease, with special focus on hypertension, diabetic kidney disease, glomerulopathies and chronic kidney disease. Recent studies demonstrate the potential role of endothelial GR in the prevention of fibrosis of kidney tissue and cell metabolism through Wnt pathways, which could have a protective effect against disease progression. Another important aspect covered in this review is blood pressure regulation though GR and eNOS. We also briefly cover potential therapies that might affect the endothelial glucocorticoid receptor and its possible clinical implications, with special interest in selective or local GR stimulation and potential mitigation of GC treatment side effects.     

New Core-Shell Nanostructures for FRET Studies: Synthesis,Characterization, and Quantitative Analysis

This work describes the synthesis and characterization of new core-shell material designed for Förster resonance energy transfer (FRET) studies. Synthesis, structural and optical properties of core-shell nanostructures with a large number of two kinds of fluorophores bound to the shell are presented. As fluorophores, strongly fluorescent rhodamine 101 and rhodamine 110 chloride were selected. The dyes exhibit significant spectral overlap between acceptor absorption and donor emission spectra, which enables effective FRET. Core-shell nanoparticles strongly differing in the ratio of donors to acceptor numbers were prepared. This leads to two different interesting cases: typical single-step FRET or multistep energy migration preceding FRET. The single-step FRET model that was designed and presented by some of us recently for core-shell nanoparticles is herein experimentally verified. Very good agreement between the analytical expression for donor fluorescence intensity decay and experimental data was obtained, which confirmed the correctness of the model. Multistep energy migration between donors preceding the final transfer to the acceptor can also be successfully described. In this case, however, experimental data are compared with the results of Monte Carlo simulations, as there is no respective analytical expression. Excellent agreement in this more general case evidences the usefulness of this numerical method in the design and prediction of the properties of the synthesized core-shell nanoparticles labelled with multiple and chemically different fluorophores.     

Spatial Pattern Characterization and Multivariate Hydrological Frequency Analysis of Extreme Precipitation in the Pearl River Basin, China

Consecutive extreme rainfall events, especially those having unfavourable spatio-temporal patterns, always trigger large floods. This paper aims to examine, through the multivariate hydrological frequency analysis, the probability of the synchronous occurrence of rainfall extremes in the Pearl River basin. The copula method together with the stationarity and independence tests, which are crucial to the valid use of statistical methods in regional frequency analyses, were applied in the study. The obtained results indicate that: (1) major precipitation events of the annual maximum 1-, 3-, 5- and 7-day rainfall recorded at 42 stations are the flat looking series and variables are independent, (2) the marginal distribution of all extreme rainfall variables in four homogeneous hydrologic regions fits the log-normal probability distribution and most of their joint distribution fits the Gumbel-Hougaard distribution, (3) on that basis the contour maps of the joint distribution of annual maximum 1-, 3-, 5- and 7-day rainfall between different regions are drawn and the probability of the synchronous occurrence of the extreme rainfalls in different regions are estimated. These findings have great practical value for the regional water resources and flood risk management and are important in exploration of the spatial patterns of rainfall extremes in the Pearl River basin in order to reveal the underlying linkages between precipitation and floods from a broader geographical perspective.     

The Problem of Wound Healing in Diabetes—From Molecular Pathways to the Design of an Animal Model

Chronic wounds are becoming an increasingly common clinical problem due to an aging population and an increased incidence of diabetes, atherosclerosis, and venous insufficiency, which are the conditions that impair and delay the healing process. Patients with diabetes constitute a group of subjects in whom the healing process is particularly prolonged regardless of its initial etiology. Circulatory dysfunction, both at the microvascular and macrovascular levels, is a leading factor in delaying or precluding wound healing in diabetes. The prolonged period of wound healing increases the risk of complications such as the development of infection, including sepsis and even amputation. Currently, many substances applied topically or systemically are supposed to accelerate the process of wound regeneration and finally wound closure. The role of clinical trials and preclinical studies, including research based on animal models, is to create safe medicinal products and ensure the fastest possible healing. To achieve this goal and minimize the wide-ranging burdens associated with conducting clinical trials, a correct animal model is needed to replicate the wound conditions in patients with diabetes as closely as possible. The aim of the paper is to summarize the most important molecular pathways which are impaired in the hyperglycemic state in the context of designing an animal model of diabetic chronic wounds. The authors focus on research optimization, including economic aspects and model reproducibility, as well as the ethical dimension of minimizing the suffering of research subjects according to the 3 Rs principle (Replacement, Reduction, Refinement).     

Khaya gum – a natural and eco-friendly biopolymer dielectric for low-cost organic field-effect transistors (OFETs)

Journal of Materials Science: Materials in Electronics - Nature provides a wide range of dielectric biopolymers that can be used in electronic devices. In this work, organic field-effect...     

Testing the randomness of shares in color visual cryptography

Pattern Analysis and Applications - The concept of black-and-white visual cryptography with two truly random shares, previously applied to color images, was improved by mixing the contents of the...     

Mass transfer of anti-cancer drug delivery to brain tumors by a multiple emulsion-based implant

The advanced use of a pH-responsive biomaterial-based injectable liquid implant for effective chemotherapeutic delivery in glioblastoma multiforme (GBM) brain tumor treatment is presented. As an implant, we proposed a water-in-oil-in-water multiple emulsion with encapsulated doxorubicin. The effectiveness of the proposed therapy was evaluated by comparing the cancer cell viability achieved in classical therapy (chemotherapeutic solution). The experimental study included doxorubicin release rates and consumption for two emulsions differing in drop sizes and structures in the presence of GBM-cells (LN229, U87 MG), and a cell viability. The results showed that the multiple emulsion implant was significantly more effective than classical therapy when considering the reduction in cancer cell viability: 85% for the emulsion-implant, and only 43% for the classical therapy. A diffusion–reaction model was adapted to predict doxorubicin release kinetics and elimination by glioblastoma cells. CFD (computational fluid dynamics) simulations confirmed that the drug release kinetics depends on multiple emulsion structures and drop sizes.     

Changes in Particle Size Distribution of Bran and Flour Obtained from Vacuum Impregnated and Infra-red Heated Wheat Grain

This study aims to provide comprehensive information on the process of vacuum impregnation of wheat grains. Vacuum impregnation, saturating materials with additional liquid components, is a well-known process originally developed to ensure leak tightness or reduce the porosity of various materials. We describe its potential uses in the food processing industry relating to the impregnation of grains and leguminous plant seeds. The objective of the study was to determine the influence of impregnation and infrared heating of wheat grains on flour efficiency, moisture content and particle size distribution in the resulting flour and bran. The experimental material comprised three varieties of wheat. The results showed that the method of preparing the wheat grains for milling combined with impregnation had a significant impact on the particle size distribution of bran but not on the particle size distribution of flour. A more complete view of the process characteristics requires further investigation of factors related to the structural and textural properties of the impregnated material, factors which are highly varied in the case of food materials and food products.