Microwave synthesis of new star shaped polyester polyols based on L-lactide

The molecular architecture of biodegradable polymers can be adjusted by incorporating multifunctional polyols into the polyester backbone to obtain branched polymers. The aim of our work was to prepare biodegradable polyester polyols based on L-lactide and castor oil in presence of tin(II) 2-ethylhexanoate as catalyst in microwave field. The polyester polyol was synthesized by core-first method which involves a polymerization of L-lactide from OH groups on castor oil. FTIR and 1 H NMR spectroscopy measurements were used to confirm the molecular structure of the synthesized products. DSC measurements were used to evaluate the crystallinity of obtained polyols. Thermal stability was investigated by thermogravimetric analysis, and results have shown the dependence of thermal stability on the arm length of the star shaped polyesters.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Comparative histology of testes of brown (Salmo trutta m. Fario) and california (Oncorhynchus mykiss) trout during the spawning period

The testes of fish are paired organs, of a variable shape in different species of fish. Their structure in the salmonid species is lobular. With the histological assays, we established that the lobes were separated by the connective tissue septa, which, given the intensity of spermatogenesis in the studied groups of fish (Salmo trutta m. Fario; Oncorhynchus mykiss) sporadically disappear, in fact, they break. In the space between the lobes there are also cross-sections of blood vessels with visible erythrocytes. During the spermatogenesis, in the interstitium there are clearly observable interstitial endocrine (Leydig) cells that excrete steroid hormones. The intensity of the spermatogenesis in the studied fish varies, which is concluded on the basis of the presence of the spermatogenesis cells. In nature, the reproductive cycle in fish is mostly based on an annual cycle, and that is why different stages of reproduction take place at a different temperature and during a different photoperiod. Hence, regardless of the same time period, the spawning time in November, different types of breeding, and finally salmon farming, point to the very important factors that influence reproduction - diet and microclimatic conditions

ANTIMICROBIAL NANOMATERIALS FOR FOOD PACKAGING APPLICATIONS

ABSTRACT: Food packaging industry presents one of the fastest growing industries nowadays. New trends in this industry, which include reducing food as well as packaging waste, improved preservation of food and prolonged shelf-life together with substitution of petrochemical sources with renewable ones are leading to development of this industrial area in diverse directions. This multidisciplinary challenge is set up both in front of food and material scientists. Nanotechnology is recently answering to these challenges, with different solutions-from improvements in materials properties to active packaging solutions, or both at the same time. Incorporation of nanoparticles into polymer matrix and preparation of hybrid materials is one of the methods of modification of polymer properties. Nano scaled materials with antimicrobial properties can act as active components when added into polymer, thereby leading to prolonged protective function of pristine food packaging material. This paper presents a review in the field of antimicrobial nanomaterials for food packaging in turn of technology, application and regulatory issues

Structural integrity and life assessment of pressure vessels - risk based approach

Risk based approach to assess structural integrity and life of pressure vessel has been presented, starring from EU PED 2014/68 and API 581, ending with use of basic fracture mechanics parameters. In the scope of risk matrix, structural integrity has been tackled by use of the Failure Assessment Diagram (FAD), while structural life was assessed by means of Paris law, using fatigue crack growth rate as relevant parameter. Several case studies have been provided to illustrate this comprehensive approach, including penstock and air storage tanks in Reversable Hydro Power Plant, and two spherical storage tanks, one for vinyl chloride monomer (VCM), the other for ammonia. Besides the assessment of integrity and life, including some important issue like over-pressurizing, roles of engineers and managers in this process is defined and explained

Lamium maculatum is a Natural Host for Cucumber mosaic virus

Lamium maculatum L. (spotted dead-nettle) is a flowering perennial ornamental that is commonly grown as a landscape plant for an effective ground cover. In June 2010, severe mosaic accompanied by reddish brown necrosis and leaf deformation was noticed on 80% of L. maculatum growing in shade under trees and shrubs in Sarajevo (Bosnia and Herzegovina). Leaves from 10 symptomatic L. maculatum plants were sampled and analyzed by double-antibody sandwich (DAS)-ELISA using commercial diagnostic kits (Bioreba AG, Reinach, Switzerland) against Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), and Impatiens necrotic spot virus (INSV), the most important viral pathogens of ornamental plants (1,2). Commercial positive and negative controls and extracts from healthy L. maculatum leaves were included in each assay. All samples tested negative for TSWV and INSV and positive for CMV. The virus was mechanically transmitted to test plants and young virus-free plants of L. maculatum using 0.01 M phosphate buffer (pH 7). The virus caused chlorotic local lesions on Chenopodium quinoa, while systemic mosaic was observed on Capsicum annuum ‘Rotund,’ Nicotiana rustica, N. glutinosa, N. tabacum ‘White Burley,’ and Phaseolus vulgaris ‘Top Crop.’ The virus was transmitted mechanically to L. maculatum and induced symptoms resembling those observed on the source plants. Inoculated plants were assayed by DAS-ELISA and all five inoculated plants of each species tested positive for CMV. The presence of CMV in L. maculatum as well as mechanically infected N. glutinosa plants was further confirmed by RT-PCR. Total RNA from symptomatic leaves was isolated using RNeasy Plant Mini Kit (Qiagen, Hilden, Germany) and RT-PCR was performed with the One-Step RT-PCR Kit (Qiagen) following the manufacturer's instructions. The primer pair, CMVAu1u/CMVAu2d, that amplifies the entire coat protein (CP) gene and part of 3′- and 5′-UTRs was used for both amplification and sequencing (4). Total RNA obtained from the Serbian CMV isolate from pumpkin (GenBank Accession No. HM065510) and a healthy L. maculatum plant were used as positive and negative controls, respectively. All naturally and mechanically infected plants as well as the positive control yielded an amplicon of the expected size (850 bp). No amplicon was observed in the healthy control. The amplified product derived from isolate 3-Lam was purified (QIAquick PCR Purification Kit, Qiagen), directly sequenced in both directions and deposited in GenBank (JX436358). Sequence analysis of the CP open reading frame (657 nt), conducted with MEGA5 software, revealed that the isolate 3-Lam showed the highest nucleotide identity of 99.4% (99.1% amino acid identity) with CMV isolates from Serbia, Australia, and the USA (GQ340670, U22821, and U20668, respectively). To our knowledge, this is the first report of the natural occurrence of CMV on L. maculatum worldwide and it adds a new host to over 1,241 species (101 plant families) infected by this virus (3). This is also an important discovery for the ornamental industry since L. maculatum is commonly grown together with other ornamental hosts of CMV in nurseries and the urban environment as well as in natural ecosystems. References: (1) Y. K. Chen et al. Arch. Virol. 146:1631, 2001. (2) M. L. Daughtrey et al. Plant Dis. 81:1220, 1997. (3) M. Jacquemond. Adv. Virus Res. 84:439, 2012. (4) I. Stankovic et al. Acta Virol. 55:337, 2011. </jats:p