Effect of polymer structure on the molecular dynamics and thermal behavior of poly(allyl acetoacetate) and copolymers

In this paper, dielectric and calorimetric studies of the small-molecule glass former allyl acetoacetate monomers as well as its newly synthetized homopolymer and copolymers with different styrene composition were performed in both the liquid and glassy states. The molecular dynamics studies by the broadband dielectric spectroscopy and the stochastic temperature modulated differential scanning calorimetry enabled us to explore relaxation processes of examined materials in the wide frequency range. We found that the copolymers reveal two co-existing glass transitions characterized by the glass transition temperatures, which are very close to those of the corresponding homopolymers. These results suggest that the copolymers exhibited some sequences of acetoacetate units with a microphase-separated morphology in agreement with the value of reactivity ratio previously determined. We investigated effects of copolymerization compositions on the glass transition temperature, the isobaric fragility index, the dielectric and calorimetric intensity, and the dynamic heterogeneity on the glass transitions of the materials.     

Cleaner production financing: possibilities and barriers

There are several players who could facilitate the promotion of cleaner production (CP) by establishing an effective financing mechanism; for instance, government, international assistance bodies, banks and other financing organizations. In a few developing countries in South East Africa and Latin America and in Vietnam several international organizations, development banks and donors have initiated and implemented projects to facilitate the introduction of CP investments. Most projects have been in the form of technical assistance grants and training to industries and/or loans at below market rates from dedicated trust funds. Yet the present level of lending through such projects is far from sufficient to trigger widespread adoption of CP. Therefore, experts from The Institute of Environmental Engineering, Lithuania performed an investigation to create a CP development scheme for developing countries.     

A comparative study on the structural and functional properties of water-soluble and alkali-soluble dietary fibres from rice bran after hot-water,ultrasound, hydrolysis by cellulase,and combined pre-treatments

The aim of the study was to estimate the optimum method to obtain water-soluble (WS-DF) and alkali-soluble (AS-DF) dietary fibres fibres from defatted rice bran (DRB) to develop functional components for food. The different pre-treatments of DRB, such as ultrasound (US) treatment, hydrolysis by cellulase (HC) and combined treatment (HC-US), were compared with hot-water (HWT) treatment on yields, and structural, physicochemical, and functional properties of WS-DF and AS-DF. Results showed that amounts of WS-DF (5.54–9.03 g/100 g) and AS-DF (7.22–9.58 g/100 g), and total dietary fibre (TDF) (42.21–45.44 g/100 g) obtained from the DRB after US, HC and HC-US treatments were significantly higher than that after HWT (6.36, 5.65 and 31.92 g/100 g, respectively). The FT-IR indicated that the effect of applied treatments on the changes of the chemical structure of polysaccharides was stronger for the WS-DF than that for the AS-DF. Scanning electron microscopy (SEM) showed that the surfaces of US-treated DFs particles were much more fractured than those after the HWT and HC. The combined HC-US treatment at 50°C for 30 min significantly enhanced the purity (85–91%) and homogeneity of RB DFs structure resulting in increased water-holding, swelling and glucose adsorption capacities compared to conventional processes maintaining acceptable bioactivity. Our study showed that conventional hot water extraction could be replaced with the ultrasonication technology as an effective tool for the modification of rice bran DFs’ structure and functional properties.     

MRI-based assessment of liver perfusion and hepatocyte injury in the murine model of acute hepatitis

Objective

To assess alterations in perfusion and liver function in the concanavalin A (ConA)-induced mouse model of acute liver failure (ALF) using two magnetic resonance imaging (MRI)-based methods: dynamic contrast-enhanced MRI (DCE-MRI) with Gd-EOB-DTPA contrast agent and arterial spin labelling (ASL).

Materials and methods

BALB/c mice were studied using a 9.4 T MRI system. The IntraGateFLASH^TM and FAIR-EPI pulse sequences were used for optimum mouse abdomen imaging.

Results

The average perfusion values for the liver of the control and ConA group were equal to 245 ± 20 and 200 ± 32 ml/min/100 g (p = 0.008, respectively). DCE-MRI showed that the time to the peak of the image enhancement was 6.14 ± 1.07 min and 9.72 ± 1.69 min in the control and ConA group (p < 0.001, respectively), while the rate of the contrast wash-out in the control and ConA group was 0.037 ± 0.008 and 0.021 ± 0.008 min^?1 (p = 0.004, respectively). These results were consistent with hepatocyte injury in the ConA-treated mice as confirmed by histopathological staining.

Conclusions

Both the ASL and DCE-MRI techniques represent a reliable methodology to assess alterations in liver perfusion and hepatocyte integrity in murine hepatitis.

     

Corporate social responsibility for implementation of sustainable energy development in Baltic States

This article analyses the main problems and challenges of corporate social responsibility in energy sector in Baltic States. Development of socially responsible business in energy sector can provide for the implementation of sustainable energy development without state interventions. This voluntary measure implemented by energy enterprises can ensure efficient public–private partnership in achieving sustainable development targets. The analysis of corporate social responsibility development in energy sector of Baltic States is provided and positive impact of corporate social responsibility on sustainable energy development is evaluated.     

Comparative assessment of policies targeting energy use efficiency in Lithuania

Energy efficiency is an important issue of European climate policy. Energy efficiency is measured by the energy intensity of an economy showing how much energy (expressed in kilograms of oil equivalent, kgoe) is used for the production of one unit (1000 EUR) of GDP. There are huge differences between EU old and new member states. Though there are some trends of energy intensity convergence between EU member states however the achieved decrease in energy intensity is attributable mostly to a loss of energy-intensive industrial capacities in the transformation process. There is a crucial difference between whether the energy intensity of a given economy decreases as a result of downscaling energy-intensive activities or because of increased energy efficiency in activities that are maintained. It is important to make sure that this distinction is made within the policy framework which at present is not the case. The aim of the paper is to assess policies targeting energy intensity decrease in Lithuania in terms of efficiency, effectiveness and efficacy and to select the best policies able to increase energy efficiency in activities that are maintained.     

An integrated approach to environmental education and research: a case study

Industrial processes have different levels of impact on the environment and there is a need to foster knowledge of the environmental consequences of industrial activities. One way of achieving this is the application of the concepts of industrial ecology (multidisciplinary research approach) to industry’s day-to-day activities. Another possible way of pursuing this goal is to use environmental education as a tool towards increasing awareness with regard to the social, political and economic relevance, as well as to the need for environmentally sound industrial activities. This paper outlines the common features of both subjects and provides an example from Kaunas University of Technology (Lithuania), where such approaches have been integrated in an M.Sc. programme.     

Controlling exchange bias in Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>/FeO composite particles prepared by pulsed laser irradiation

Spherical iron oxide nanocomposite particles composed of magnetite and wustite have been successfully synthesized using a novel method of pulsed laser irradiation in ethyl acetate. Both the size and the composition of nanocomposite particles are controlled by laser irradiation condition. Through tuning the laser fluence, the Fe₃O₄/FeO phase ratio can be precisely controlled, and the magnetic properties of final products can also be regulated. This work presents a successful example of the fabrication of ferro (ferri) (FM)/antiferromagnetic (AFM) systems with high chemical stability. The results show this novel simple method as widely extendable to various FM/AFM nanocomposite systems.     

Design of small-molecule peptidic and nonpeptidic Smac mimetics

Smac/DIABLO is a protein released from mitochondria into the cytosol in response to apoptotic stimuli. Smac promotes apoptosis at least in part through antagonizing inhibitor of apoptosis proteins (IAPs), including XIAP, cIAP-1, and cIAP-2. Smac interacts with these IAPs via its N-terminal AVPI binding motif. There has been an enormous interest in academic laboratories and pharmaceutical companies in the design of small-molecule Smac mimetics as potential anticancer agents. This task is particularly challenging because it involves targeting protein-protein interactions. Nevertheless, intense research has now generated potent, specific, cell-permeable small-molecule peptidomimetics and nonpeptidic mimetics. To date, two types of Smac mimetics have been reported, namely, monovalent and bivalent Smac mimetics. The monovalent compounds are designed to mimic the binding of a single AVPI binding motif to IAP proteins, whereas the bivalent compounds contain two AVPI binding motif mimetics tethered together through a linker. Studies from several groups have clearly demonstrated that both monovalent and bivalent Smac mimetics not only enhance the antitumor activity of other anticancer agents but also can induce apoptosis as single agents in a subset of human cancer cell lines in vitro and are capable of achieving tumor regression in animal models of human cancer. In general, bivalent Smac mimetics are 100-1000 times more potent than their corresponding monovalent Smac mimetics in induction of apoptosis in tumor cells. However, properly designed monovalent Smac mimetics can achieve oral bioavailability and may have major advantages over bivalent Smac mimetics as potential drug candidates. In-depth insights on the molecular mechanism of action of Smac mimetics have been provided by several independent studies. It was shown that Smac mimetics induce apoptosis in tumor cells by targeting cIAP-1/-2 for the rapid degradation of these proteins, which leads to activation of nuclear factor kappaB (NF-kappaB) and production and secretion of tumor necrosis factor alpha (TNFalpha). TNFalpha promotes formation of a receptor-interacting serine-threonine kinase 1 (RIPK1)-dependent caspase-8-activating complex, leading to activation of caspase-8 and -3/-7 and ultimately to apoptosis. For the most efficient apoptosis induction, Smac mimetics also need to remove the inhibition of XIAP to caspase-3/-7. Hence, Smac mimetics induce apoptosis in tumor cells by targeting not only cIAP-1/-2 but also XIAP. The employment of potent, cell-permeable, small-molecule Smac mimetics has yielded important insights into the regulation of apoptosis by IAP proteins. To date, at least one Smac mimetic has been advanced into clinical development. Several other Smac mimetics are in an advanced preclinical development stage and are expected to enter human clinical testing for the treatment of cancer in the near future.