A preparative-scale synthesis of O-substituted β-D-glucopyranosides catalyzed by immobilized β -glucosidase in reverse hydrolytic reactions was attempted by using our novel reaction system. In this system the alcohols as solvents were replaced with organic solvents as diluting components. We found that not only 1,2-diacetoxyethane, but also triacetin is a suitable diluting solvent, because they can reduce the heterogeneity in the reverse hydrolytic reaction mixtures. Because of the high boiling point of the solvents, an extraction method was used for the isolation of products after reverse hydrolysis. This method resulted in higher yields (15-25%) than our original evaporation method (11-19%).
A method is described for Rb and Sr concentration determinations in rocks by radioisotope X-ray fluorescence analysis. The
yield/concentration ratios were established by increasing the concentrations of the examined elements in the sample and recording
each spectrum. The analytical error in the 100-1,000 ppm concentration range was 2–4%, and for 50 ppm about 10%, and the detection
limit was 5–10 ppm.
Revealed comparative advantages are widely used by the global literature to analyse international trade flows, though agricultural trade is usually neglected in empirical works. Moreover, the determinants of revealed comparative advantages are scarcely investigated. This article analyses revealed comparative advantages in European Union’s cheese trade from 1990 to 2013 and identifies its determinants by using panel data econometrics. Results suggest that GDP/capita, geographical indication, and EU membership are positively, while foreign direct investment (FDI) is negatively related to revealed comparative advantages.
The carbon balance of the sandy pasture (Bugac) and the mountain meadow (Mátra) varied between −171 and 96 gC m−2 year−1, and −194 and 14 gC m−2 year−1, respectively, during the study period (2003–2009). Large part of interannual variability of net ecosystem exchange (NEE) was explained by the variation of the annual sum of precipitation in the sandy grassland ecosystem, while this relationship was weaker in the case of the mountain meadow on heavy clay soil. These different responses are largely explained by soil texture characteristics leading to differences in soil water contents available to plants at the two grasslands. The grassland on heavy clay soil was more sensitive to temporal distribution of rainfall for the same reason. The mountain meadow therefore seems to be more vulnerable to droughts, while the sandy grassland is better adapted to water shortage. The precipitation threshold (annual sum), below which the grassland turns into source of carbon dioxide on annual basis, is only 50–80 mm higher than the 10 years average precipitation sum. In extremely dry years (2003, 2007 and 2009), even the sandy grassland ecosystem was not stable enough to maintain its sink character.
The immobilization of enzymes has not been reported earlier on the two-dimensional crystalline bacterial cell surface (S-layer). In this study we tested S-layer isolated from Bacillus stearothermophilus PV72 for enzyme (ß-glucosidase, hexokinase and aldolase) immobilization. The carbodiimide method gave yields less than 5%. The yields of co-cross-linking method with glutaraldehyde were enhanced compared to the carbodiimide method, but the yield was higher than 10% only in the case of ß-glucosidase. Because of the fine structure of S-layer, immobilized enzymes could be removed from reaction mixtures only by centrifugation, therefore these preparations were entrapped in calcium alginate gel. The yields of entrapping procedures were between 15% and 37%. It was presumed that the new immobilized ß-glucosidase preparation could be used in a preliminary testing for flavour enrichment of wines. Efficiency of this preparation was compared to that of the immobilized ß-glucosidase on Acrylex C-100 support described earlier. We found that the immobilization of ß-glucosidase on both Acrylex C-100 support and S-layer followed by gel entrapping resulted in active enzyme preparations that could be used for flavour enrichment of wines without enhancing their protein content.
Authors:J. Gál, Cs. Jakab, B. Balogh, T. Tóth, and B. Farkas
The occurrence of a periosteal chondroma (juxtacortical chondroma) in an adult male
is documented for the first time. The chondroma developed near the right shoulder joint from the periosteal membrane, causing partial atrophy in the surrounding skeletal muscles. In the chondroma tissues widespread central necrosis and secondary calcium salt deposition were observed. Monomorphic chondrocytes were irregularly spread in the chondromucin matrix. The lizard had locomotor problems due to irritation of the periosteum and reduced movement of the bones constituting the shoulder joint caused by the chondroma.
Authors:Sz. Czóbel, O. Szirmai, J. Nagy, J. Balogh, Zs. Ürmös, E. Péli, and Z. Tuba
Grassland ecosystems in the Carpathian Basin may be particularly vulnerable to current and predicted changes in precipitation, and ecosystem responses to potential effects of water are not well understood. To examine how water addition can affect the species composition and structure, and CO
-flux of a Central European natural steppe plant community, grassland monoliths were irrigated for three consecutive years at Gödöllő, from 2002 through 2004. The loess grassland studied by
is a characteristic plant association of Hungary and similar vegetation can be found in other temperate regions. The treatment consisted of spray irrigation during night-time only in the growing season as well as aboveground biomass removal twice per year. Interannual and intraannual dynamics of species richness, Shannon Diversity, percentage cover, and different functional groups (monocots/dicots; plant life forms; social behaviour types; C
plants), and Net Ecosystem CO
Exchange in treated and untreated permanent plots, were studied simultaneously. To measure NEE and water vapour at stand level a self-developed, portable, non-destructive open chamber system (d=60cm) was used. The majority of the examined parameters varied considerably among years at both irrigated and control, but concerning carbon fluxes water addition effects were evident in dry periods only. At the treated plots, in general species richness, Shannon Diversity, the number of plant life forms and social behaviour types, the ratio of dicots and C
plants declined with addition of water. Our study proved that decline in species richness and Shannon diversity is not necessarily followed by the reduction of stand physiological (synphysiological) processes.
Authors:J. T. Kundrát, Zs. Balogh, S. Harangi, B. Tóthmérész, and E. Simon
The contamination level of oxbows depends on both natural and anthropogenic effects. The aim of our study was to identify those abiotic and biotic factors that determine the contamination level of oxbows. The effect of anthropogenic activities, seasonality, and vegetation types was studied on the contamination level of surface water of oxbows. The following chemical variables were measured: suspended solid, ammonium, nitrate, chlorophyll-a, Al, Ba, Fe, Mn, Pb, Sr and Zn from eight oxbows from 2013 summer to 2014 autumn in the Upper Tisza region in Eastern Hungary. Three of the studied oxbows were protected, four oxbows were used for fishing and one oxbow was contaminated with wastewater. Our findings revealed that anthropogenic activities had remarkable effect on the contamination level of oxbows. Seasonality also influenced the contamination level, except the concentration of suspended solid, chlorophyll-a and manganese. Significant differences were found among vegetation types for the concentration of suspended solids, aluminium, iron, manganese and lead. The high level of iron concentration was not explained by the anthropogenic activities, suggesting that the quality of oxbows depends on both natural and anthropogenic effects.