An alginate-layer technique for culture of Brassica oleracea L. protoplasts

Ten accessions belonging to the Brassica oleracea subspecies alba and rubra, and to B. oleracea var. sabauda were used in this study. Protoplasts were isolated from leaves and hypocotyls of in vitro grown plants. The influence of selected factors on the yield, viability, and mitotic activity of protoplasts immobilized in calcium alginate layers was investigated. The efficiency of protoplast isolation from hypocotyls was lower (0.7 ± 0.1 × 106 ml−1) than for protoplasts isolated from leaf mesophyll tissue (2 ± 0.1 × 106 ml−1). High (70–90%) viabilities of immobilized protoplasts were recorded, independent of the explant sources. The highest proportion of protoplasts undergoing divisions was noted for cv. Reball F1, both from mesophyll (29.8 ± 2.2%) and hypocotyl (17.5 ± 0.3%) tissues. Developed colonies of callus tissue were subjected to regeneration and as a result plants from six accessions were obtained

Restorative biocompatible polymer composites on the base of epoxy-resin filled by surface-modified disperse utilizated solid waste of industrial paper products

The paper industry is one of the sources of environment pollution. Therefore, the problem of efficient utilization of such wastes is an urgent one. One of the possible effective methods of paper industry waste recycling can be the application in epoxy composites. The review of literature proves a high scientific and industrial actuality of this thematic. Optical microscopy shows that 20 wt% of micro- and meso-particles of lignocellulose from waste-paper utilization leads to changes in morphology of composite due to interactions between phases. As result, the key mechanic (modulus at bending, resistance to wear) and resistant (swelling, fire- resistance) parameters changed. At the same time, 20wt% filling do not importantly change compression and bending strength parameters. Filled composites (as fresh as aged) are noticeable more resistant in acetone-containing solvents. Effect of filling on resistance in H2O2 depends on its concentration and age of templates: aged 20%-filled composites are more resistant than unfilled (in 35% H2O2), but fresh 10%-filled composite destruct quickly (unlike unfilled) in high-concentrated (60%) H2O

Strength and Chemical Resistance of Composites Based on Epoxy Resins, Filled with Gypsum in the Original and Water­hardened Forms

This paper reports the results of studying epoxy compositions with gypsum taken in the form of dispersed powders in the original and water-hardened form. The exact pattern has been shown in the way the introduction of a gypsum additive in the amount of 50 % by weight affects the strength, chemical stability, and morphology of the composites.Under conventional heat treatment (60‒110 °C) of the hardened composites, the maximum stress at compression σm and the elasticity module at compression Ес, as well as wear resistance, decrease after the introduction of gypsums (of both types). At the same time, after a hard (destructive) heating at 250‒260 °C, the elasticity module Ес of the hardened composites increases. The maximum stress at compression σm is also increased. The same applies to the wear resistance, which grows especially noticeably after 250 °C.The micro-hardness after filling is prone to increase but the fragility of epoxy-gypsum composites does not make it possible to measure it when a punch (a steel hemisphere) penetrates it deeper than 20 µm. However, after the heat treatment at 250‒260 °C, the unfilled polymer, on the contrary, is embrittled while the filled ones are plasticized, thus showing a high micro-hardness at significant (30‒50 µm) immersion.The composites with gypsum, in contrast to the unfilled ones, do not disintegrate in acetone and retain integrity at any aging duration (up to 75 days and beyond). In this case, the original gypsum produces a composite with less swelling in acetone than the hardened gypsum. Based on the data from atomic-strength microscopy (ASM) microscopy, the morphologies of the non-filled composite, the composites with the hardened gypsum and original gypsum are different. The original gypsum forms a composite with a more pronounced (possibly crystalline) filler structure; the morphology for the hardened composite reflects the distribution of inert particles; for the unfilled composite (H-composite), only pores are visible against the background of a relatively smooth relie

The Influence of Carbon Nanotubes on the Physical and Chemical Properties of Nanocomposites Based on Unsaturated Polyester Resin

The new actual scientific direction is in the development of different nanocomposites and the study of their medical–biological, physicochemical, and physicomechanical properties. One way to expand the functionality of nanocomposites and nanomaterials is to introduce carbon nanostructures into the polymer matrix. This study presents the properties of unsaturated polyester resins (Estromal, LERG S.A.) based on PET recyclate with multi-walled carbon nanotubes (MWCNTs): their mechanical and thermomechanical characteristics, resistance to ultraviolet radiation (UV-vis), and chemical resistance properties. The properties of the obtained materials were characterized using physical–chemical research methods. The changes in the properties of the composites for MWCNT content of 0.1, 0.3, and 0.5 wt % were determined. The results showed positive influences on the thermomechanical and mechanical properties of nanocomposites without significant deterioration of their gloss. Too much CNT added to the resin leads to heterogeneity of the composite structure

The State and Dynamics of Biological Communities in the Rybinsk Reservoir under Climate Changes

На основе анализа многолетних данных по структурным характеристикам фито- (1954–2014 гг.) и зоопланктона (2004–2013 гг.), а также содержанию хлорофилла в воде и донных отложениях (2009–2014 гг.) Рыбинского водохранилища (Верхняя Волга, Россия) показано, что современные климатические изменения приводят к трансформации состояния и динамики биологических сообществ водохранилища, характерной при увеличении трофии пресноводных экосистем. После аномально жаркого лета 2010 г. выявлен резкий подъем концентрации хлорофилла в воде с преобладанием величин, характерных для эвтрофных и высокоэвтрофных вод. Распределение растительных пигментов в донных отложениях в разные годы было сходным и отражало характерную для водохранилища специфику структуры грунтового комплекса. В сезонной динамике биомассы фитопланктона и концентрации хлорофилла летний максимум, обусловленный развитием цианобактерий, стал доминировать над весенним. В структуре фитопланктона увеличились пропорции цианобактерий и миксотрофных фитофлагеллят, отмечены инвазии солоновато-водных диатомовых и уменьшение размеров клеток. В сезонной динамике биомассы зоопланктона сформировался второй позднелетний (август) пик, максимально проявившийся в аномально жаркое лето 2010 г. Кроме того, наблюдалось смещение на одну–две недели сроков начала и окончания сезонного цикла ряда видов зоопланктона относительно 1960–1970-х гг. Появление летнего дефицита растворенного кислорода (О2 1–4 мг/л в слое 1–7 м над дном) привело к локальному изменению вертикального распределения ракообразных-фильтраторов и снижению их обилия до трех разThe long-term data on structural characteristics of phytoplankton (1954–2014) and zooplankton (2004–2013), as well as chlorophyll content in the water and bottom sediments (2009–2014) in the Rybinsk Reservoir (Upper Volga, Russia) were analyzed. It was shown that the modern climate changes lead to transformation in the state and dynamics of biological communities that is characteristic of the trophicity increase. After the abnormally hot summer of 2010 a sharp rise in chlorophyll content in water with a predominance of values typical for eutrophic and highly eutrophic conditions was detected. Distribution of plant pigments in the bottom sediments was similar in different years, which shows the specific character of the sediment complex structure in the reservoir. In the seasonal dynamics of phytoplankton biomass and chlorophyll concentration the summer maximum caused by development of cyanobacteria began to dominate above the spring one. In the structure of phytoplankton the proportions of cyanobacteria and myxotrophic phytophagellates increased, the invasion of brackish-water diatoms was marked, and diminution of the cell size was noted. In seasonal dynamics of zooplankton biomass the second late peak was formed in August and it was particularly pronounced in the abnormally hot summer of 2010. In addition, there was a 1–2 week shift in timing of the beginning and ending in seasonal cycle of a number of zooplankton species relative to the 1960–1970s. Appearance of a summer dissolved oxygen deficiency (up to 1–4 mg O2/L in the layer of 1–7 m above the bottom) resulted in a local change in the vertical distribution of crustacean filtrators and decrease in their abundance up to three time