Cover Picture: Macromol. Mater. Eng. 9/2005

Summary: Inverse gas chromatography under finite surface coverage conditions (IGC‐FC) was used for the investigation of sorption of hexane, benzene, chloroform and tetrahydrofuran on macroporous crosslinked poly[(glycidyl methacrylate)‐co‐(ethylene glycol dimethacrylate)], poly(GMA‐co‐EGDMA), and copolymer modified with ethylene diamine, EDA, poly(GMA‐co‐EGDMA)‐en, in the temperature range 333–363 K. Two poly(GMA‐co‐EGDMA) samples with different porosity parameters were synthesized by suspension copolymerization and modified using a ring‐opening reaction of the pendant epoxy groups with EDA. The specific surface areas of the initial and modified copolymer samples were determined by the BET method from low temperature nitrogen adsorption isotherms (77 K). The adsorption isotherms determined from chromatographic peaks of adsorbates were analyzed using the BET theoretical model and used for estimation of the surface area, isosteric heat of adsorption and the adsorption energy distribution on the surface of the initial and modified copolymer samples. It was observed that the adsorbate nature and the properties of the solid surface of the initial and modified copolymer governed the uptake of adsorbate by the copolymer. The deviations observed for the S_a values obtained by the BET method from the low temperature nitrogen adsorption isotherms and hexane was attributed not only to the difference in molecule size, but also to the specific polymer‐adsorbate interactions. The isosteric heat of adsorption approached a constant value with increasing adsorbate loading. A large variation in the shapes of the q_st‐α curves resulted from strong acid‐base interactions, as well as dissolution phenomena. Of the four studied adsorbates, chloroform was shown to have the greatest affinity towards the surface of the investigated polymer samples.

Adsorption isotherms of hexane on sample 1 and 1a.     

Biological activity and chemical composition of different berry juices

Total phenolics, total anthocyanins, mineral content, radical scavenging activity and antiproliferative activity against human cancer cell lines were evaluated in fresh pressed juices of five different berries. Total phenolic content ranged from 133.0 to 260.3 mg of gallic acid equivalents/100 g of fresh weight, for red currant and black currant, respectively. Bilberry juice contained the highest amount of total anthocyanins (0.18%). Significant correlation between total phenolics content and radical scavenging activity was observed (r = −0.980; p < 0.01). All examined juices showed antiproliferative activity in dose-dependent manner with IC₅₀ ranging from 10.2 to 70.5 μl/ml. Black currant juice was the most effective inhibitor of proliferation in all cell lines tested (HeLa, Fem X, LS 174, MCF-7 and PC-3). Significant correlations of acidity and total anthocyanin content with antiproliferative activity of berry juices on HeLa cells, Fem X cells and MCF-7 cells were noticed. Berry juices are good sources of some minerals and contribute significantly to daily intake of these micronutrients.     

Ultrasound Pretreatment as an Useful Tool to Enhance Egg White Protein Hydrolysis: Kinetics,Reaction Model,and Thermodinamics

The impact of ultrasound waves generated by probe‐type sonicator and ultrasound cleaning bath on egg white protein susceptibility to hydrolysis by alcalase compared to both thermal pretreatment and conventional enzymatic hydrolysis was quantitatively investigated. A series of hydrolytic reactions was carried out in a stirred tank reactor at different substrate concentrations, enzyme concentrations, and temperatures using untreated, and pretreated egg white proteins (EWPs). The kinetic model based on substrate inhibition and second‐order enzyme deactivation successfully predicts the experimental behavior providing an effective tool for comparison and optimization. The ultrasound pretreatments appear to greatly improve the enzymatic hydrolysis of EWPs under different conditions when compare to other methods. The apparent reaction rate constants for proteolysis (k₂) are 0.009, 0.011, 0.053, and 0.045 min^?1 for untreated EWPs, and those pretreated with heat, probe‐type sonicator, and ultrasound cleaning bath technologies, respectively. The ultrasound pretreatment also decreases hydrolysis activation (E_a) and enzyme deactivation (E_d) energy, enthalpy (ΔH), and entropy (ΔS) of activation and for the probe‐type sonication this decrease is 61.7%, 61.6%, 63.6%, and 32.2%, respectively, but ultrasound has little change in Gibbs free energy value in the temperature range of 318 to 338 K. The content of sulfhydryl groups and ζ potential show a significant increase (P < 0.05) for both applied ultrasound pretreatments and the reduction of particle size distribution are achieved, providing some evidence that the ultrasound causes EWP structural changes affecting the proteolysis rate.     

Protective Role of Melatonin and Its Metabolites in Skin Aging

The skin, being the largest organ in the human body, is exposed to the environment and suffers from both intrinsic and extrinsic aging factors. The skin aging process is characterized by several clinical features such as wrinkling, loss of elasticity, and rough-textured appearance. This complex process is accompanied with phenotypic and functional changes in cutaneous and immune cells, as well as structural and functional disturbances in extracellular matrix components such as collagens and elastin. Because skin health is considered one of the principal factors representing overall “well-being” and the perception of “health” in humans, several anti-aging strategies have recently been developed. Thus, while the fundamental mechanisms regarding skin aging are known, new substances should be considered for introduction into dermatological treatments. Herein, we describe melatonin and its metabolites as potential “aging neutralizers”. Melatonin, an evolutionarily ancient derivative of serotonin with hormonal properties, is the main neuroendocrine secretory product of the pineal gland. It regulates circadian rhythmicity and also exerts anti-oxidative, anti-inflammatory, immunomodulatory, and anti-tumor capacities. The intention of this review is to summarize changes within skin aging, research advances on the molecular mechanisms leading to these changes, and the impact of the melatoninergic anti-oxidative system controlled by melatonin and its metabolites, targeting the prevention or reversal of skin aging.     

Hybrid Constructed Wetland Selection as a Group Decision-Making Problem

Water Resources Management - This paper proposes a framework based on the group analytic hierarchy process for identifying most desirable technologies for constructed wetland segmentation. A method...     

Performance Analysis of Interference-Limited Mobile-to-Mobile κ–μ Fading Channel

Wireless Personal Communications - In this paper, a wireless cooperative network, with two sections, operating over multipath mobile-to-mobile interference-limited fading channel is considered. The...     

Gender Differences in the Expression and Cellular Localization of Lipin 1 in the Hearts of Fructose-Fed Rats

To give new insight to alterations of cardiac lipid metabolism accompanied by a fructose-rich diet (FRD), rats of both sexes were exposed to 10 % fructose in drinking water during 9 weeks. The protein level and subcellular localization of the main regulators of cardiac lipid metabolism, such as lipin 1, peroxisome proliferator-activated receptor α (PPARα), peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α), carnitine palmitoyltransferase I (CPTI), and CD36 were studied. Caloric intake in fructose-fed rats (FFR) of both sexes was increased. Circulating triacylglyceroles (TAG) and non-esterified fatty acids were increased in male FFR, while females increased visceral adiposity and blood TAG. Total expression of lipin 1 in cardiac cell lysate and its cytosolic and microsomal level were increased in the hearts of male FFR. PPARα and PGC-1α content were decreased in the nuclear extract. In addition, cardiac deposition of TAG in male FFR was elevated, as well as inhibitory phosphorylation of insulin receptor substrate 1 (IRS-1). In contrast, in female FFR, lipin 1 level was increased in nuclear extract only, while overall CPTI expression and phosphorylation of IRS-1 at serine 307 were decreased. The results of our study suggest that fructose diet causes gender-dependent alterations in cardiac lipid metabolism. Potentially detrimental effects of FRD seem to be limited to male rats. Most of the observed changes might be a consequence of elevated expression and altered localization of lipin 1. Increased inhibitory phosphorylation of IRS-1 is possible link between cardiac lipid metabolism and insulin resistance in FFR.     

An overview of forestry journals in the period 2006–2010 as basis for ascertaining research trends

Articles published between January 1, 2006 and December 31, 2010 in 42 forestry journals (N = 16,258) were collected and, depending on their content and key words, classified in one of 22 sub-disciplines. Among the forestry sub-disciplines, the following are currently dominant: Mensuration and inventories, Forest management, Plant ecophysiology and Wood science. PCA ordination was used to visualize grouping tendencies and data separation. For each component, a number of characteristics contributed to the total variation, and significant importance was attached to those with the highest loading factors. The first component included Mensuration and inventories, Plant ecophysiology, Vegetation ecology and Forest management, as the highest loading factors. The second components comprised Sociological aspects, Plant ecophysiology, Wood science and Forest management. The most pronounced increase trend over the five-year period is noted for Genetics and breeding, Vegetation ecology, Fuels and energy, while the most pronounced decrease trend is visible in Forest health, Forest fire, Sociological aspects and Forest products. PCA suggests the existence of three groups of journals: the first group comprises Forest Ecology and Management and Canadian Journal of Forest Research, the dominating two, the second group comprises Annals of Forest Science, Plant Ecology, Tree Physiology and Trees-Structure and Function, while the rest of the journals belong to the third group. The Canadian Journal of Forest Research is the most diversified, while Tree Genetics and Genomes, Silvae Genetica and Tree-ring Research are narrowly specialized.