Biodegradation study of some food packaging biopolymers based on PVA

Abstract Polymers are a common choice as protective materials since they combine flexibility, variable sizes and shapes, relatively light weight, stability, resistance to breaking, barrier properties and perceived high-quality image with cost-effectiveness. Currently, mainly non-biodegradable petroleum-based synthetic polymers are used as packaging materials for foods, because of their availability, low cost and functionality. However, biopolymers can be made from renewable resources without the environmental issues of petroleum-based polymers and with the additional advantage of being available from renewable sources or as by-products or waste-products from the food and agriculture industries. The aim of this study was to test some food packaging biopolymers based on PVA. In this respect, some biopolymers for food packaging applications were subjected to biodegradation tests by covering the tested samples with soil. The samples were incubated in known temperature and humidity conditions. The experiment lasted 45 days, after that the samples were washed, weighed and the biodegradation degree was calculated. The obtained results shows that PVA is a promising material for food packaging usage, as it is made from renewable resources and it is environmentally friendly.Â

Access Technologies (AT) for Students with Visual Impairments

AbstractThe present paper aims to highlight the importance of access technologies (AT) to studying the Information Technology (ICT) for students with visual impairments. The research has shown that students with visual impairments are attracted to new technologies and even though at first they have not proven confidence in the benefits of studying this subject, towards the end of the school year the situation changed, meaning that most students were delighted to study this subject and also in the benefits that their acquisitions have upon their personal and interpersonal development

Relationship between stomatal conductance and drought susceptibility index in alfalfa (Medicago sativa L.)

Global climate change evidentiate an increase in drought frequencies. In this context the strategies for sustainable use of water and drought resistance improvement based on the physiological traits are important and physiological approaches should be integrated in conventional breeding. Research was performed on 16 alfalfa genotypes under vegetation house conditions at two watering levels and field analyses. The objective was to identify the available genetic variation and to establish efficient physiologycall traits for testing which might positively influence alfalfa performance under drought conditions. Our research were focused on stomatal conductance and chlorophyll content. There is a very significant negative correlation between the drought sensitivity index and the stomatal conductance of alfalfa genotypes sown for fodder (r = - 0.70***). This means that genotypes with a higher stomatal conductance were more productive (low drought sensitivity index means better drought adaptability, so higher production) indicating that stomatal resistance has a very significant impact on production under stress conditions. There is a very significant positive correlation between the chlorophyll content and the stomatal conductance of alfalfa genotypes from the comparative culture sown for fodder (r = 0.79***), which shows that stomatal closure is the main factor limiting photosynthetic activity under water limiting conditions

Isolation and Characterization of New Microsatellite Markers for the Invasive Softshell Clam, Mya arenaria (L.) (Bivalvia: Myidae)

The invasive softshell clam (Mya arenaria Linnaeus, 1758) is native to the northwestern region of the Atlantic Ocean. This species has been introduced in the northeast Pacific and along the European coasts, due to intense naval transports and aquaculture, and it is now present in all the European seas. In this paper we describe seven new microsatellite loci for Mya arenaria. The isolated loci are polymorphic with a number of alleles per locus between 6 and 14. The observed and expected heterozygosities ranged from 0.417 to 0.951, and from 0.643 to 0.895, with an average of 0.716 and 0.775, respectively. These microsatellite markers should be useful in analyzing this species’ genetic diversity, which could explain various processes of its invasion history

Extraction, purification, and clumped isotope analysis of methane (δ13CDH3and δ12CD2H2) from sources and the atmosphere

Measurements of the clumped isotope anomalies (13CDH3 and 12CD2H2) of methane have shown potential for constraining methane sources and sinks. At Utrecht University, we use the Thermo Scientific Ultra high-resolution isotope-ratio mass spectrometer to measure the clumped isotopic composition of methane emitted from various sources and directly from the atmosphere. We have developed an extraction system with three sections for extracting and purifying methane from high (>1%), medium (0.1% to 1%), and low-concentration (<0.1%) samples, including atmospheric air (g1/42ppmCombining double low line0.0002%). Depending on the methane concentration, a quantity of sample gas is processed that delivers 3±1mL of pure methane, which is the quantity typically needed for one clumped isotope measurement. For atmospheric air with a methane mole fraction of 2ppm, we currently process up to 1100L of air. The analysis is performed on pure methane, using a dual-inlet setup. The complete measurement time for all isotope signatures is about 20h for one sample. The mean internal precision values of sample measurements are 0.3±0.1‰ for 13CDH3 and 2.4±0.8‰ for 12CD2H2. The long-term reproducibility, obtained from repeated measurements of a constant target gas, over almost 3 years, is around 0.15‰ for 13CDH3 and 1.2‰ for 12CD2H2. The measured clumping anomalies are calibrated via the 13CDH3 and 12CD2H2 values of the reference CH4 used for the dual-inlet measurements. These were determined through isotope equilibration experiments at temperatures between 50 and 450°C. We describe in detail the optimized sampling, extraction, purification, and measurement technique followed in our laboratory to measure the clumping anomalies of methane precisely and accurately. This paper highlights the extraction and one of the first global measurements of the clumping anomalies of atmospheric methane

Isolation and Characterization of the First Microsatellite Markers for the Endangered Relict Mussel Hypanis colorata (Mollusca: Bivalvia: Cardiidae)

Hypanis colorata (Eichwald, 1829) (Cardiidae: Lymnocardiinae) is a bivalve relict species with a Ponto-Caspian distribution and is under strict protection in Romania, according to national regulations. While the species is depressed in the western Black Sea lagoons from Romania and Ukraine, it is also a successful invader in the middle Dniepr and Volga regions. Establishing a conservation strategy for this species or studying its invasion process requires knowledge about the genetic structure of the species populations. We have isolated and characterized nine polymorphic microsatellite markers in H. colorata. The number of alleles per locus ranged from 4 to 28 and the observed heterozygosity ranged from 0.613 to 1.000. The microsatellites developed in the present study are highly polymorphic and they should be useful for the assessment of genetic variation within this species

Perovskite type nanopowders and thin films obtained by chemical methods

The review presents the contribution of the authors, to the preparation of two types of perovskites, namely BiFeO3 and LaCoO3, by innovative methods. The studied perovskites were obtained as powders, films and sintered bodies. Their complex structural and morphological characterization is also presented. The obtained results have underlined the important influence of the method of preparation on the properties of the synthesized perovskites

Évaluation de la tension artérielle et de la pression du pouls dans le syndrome métabolique

Objectif. L’objectif de notre étude est d’évaluer la pression artérielle et la pression différentielle chez les patients atteints du syndrome métabolique (SM), afin de déceler et de prévenir les complications cardiovasculaires qui peuvent survenir chez ces patients. Matériels et méthodes. L’analyse des cas‑témoin a été faite sur un total de 1528 patients, dans un cabinet de médecine familiale, les sujets étant répartis en deux groupes: le lot avec SM et le groupe témoin (sans SM). Le groupe avec SM se composait de 388 patients diagnostiqués selon les critères harmonisés. Le groupe témoin sans SM était composé de 1140 patients n’ayant pas présenté au moins trois critères diagnostiques du syndrome métabolique. Résultats. La pression différentielle, les valeurs calculées pour les patients atteints de syndrome métabolique ont été généralement plus élevées que le taux moyen escompté à 40 mmHg, avec une valeur moyenne de 47,86 ± 12,02 mmHg. Le groupe de contrôle a une valeur moyenne (40,28 ±12.20 mmHg) du pouls, une pression significativement plus faible (p<0.0001). Conclusions. La tension différentielle est associée aux complications cardiovasculaires positives, en particulier chez les personnes âgées et surtout aux valeurs supérieure ou égale à 60 mmHg, mais cette association n’est pas indépendante de la tension artérielle