Parameter optimization for the enzymatic hydrolysis of sunflower oil in high-pressure reactors

This study is concerned with the hydrolysis of sunflower oil in the presence of lipase preparation Lipolase 100T (Aspergillus niger lipase). Supercritical carbon dioxide was used as a solvent for this reaction. In a high-pressure stirred tank reactor operated in a batch mode, the effects of various process parameters (temperature, pressure, enzyme/substrate ratio, pH, and oil/buffer ratio) were investigated to determine the optimal reaction rate and conversion for the hydrolysis process. The optimal concentration of lipase was 0.0714 g/mL of CO₂-free reaction mixture, and the highest conversions of oleic acid (0.193 g/g of oil phase) and linoleic acid (0.586 g/g of oil phase) were obtained at 50°C, 200 bar, pH=7, and an oil/buffer ratio of 1∶1 (w/w).     

Changes in the amount of kidney pigmented macrophage aggregates throughout the breeding cycle of female Ohrid trout, Salmo letnica Kar. (Teleostei, Salmonidae)

Changes in fish macrophages (Macs) are useful indicators of environmental pressures, but responses due to chemical and nonchemical stresses may be confounded by natural sources of variability. These may include sex and gonadal stage. In this study, we start addressing the following question: is the seasonally dependent ovary stage a factor to consider when using kidney Macs as biomarkers? To tackle this problem, the relative amount of pigmented Macs in kidney (head, trunk, and tail portions) was stereologically estimated in Ohrid trout, and related with the breeding status. The amount of Macs significantly increased from pre vitellogenesis to late vitellogenesis and showed a decreasing trend then after, with lower values noted after spawning in the head (1.9% versus 7.5% versus 2.0%), trunk (1.8% versus 7.5% versus 2.5%), and tail (2.5% versus 6.7% versus 2.9%) kidney. The decrease seen at spawning was significant in head and trunk kidney, and at post spawning it was significant for all kidney portions. The amounts of Macs were positively correlated with the ovary relative weights and plasma estradiol levels. We proved for the first time that fish kidney pigmented Macs can vary in amount during the breeding cycle. Our data, combined with literature, strongly support that the sex‐steroid profile and kidney status‐seasonal remodeling both influence the Macs pool; likely not only in female trout. So, while increases in Macs may warn of ecosystem problems, we show that using kidney Macs for biomonitoring should also take into account seasonally, particularly that related with ovary maturation. Microsc. Res. Tech. 2011. © 2011 Wiley Periodicals, Inc.     

Assessment of powder flow characteristics in incoherent soup concentrates

Soup mixtures represent specific flow characteristics while particles of different sizes and properties form a homogeneous mixture. In such mixtures, particle–particle interactions differ with addition of different fat types. This study was done to present a characterization and comparison of the cohesion index, powder flow speed dependency and caking properties of four different aggregates of fat particles with three different moisture contents, used in various compositions of powdered soup concentrates. ESEM micrographs have shown that different fat types bind particles differently. The moisture content of cream soup concentrates has a significant influence on cake height ratio of all cycles – more moisture causes higher cake height ratios (from r_s = 0.86 to r_s = 0.76; p < 0.05). Cream soup concentrates cake strength values are also significantly influenced by the mixtures moisture content – higher moisture content samples showed higher cake strength values (r_s = 0.73, p < 0.05). There is a significant correlation between compaction coefficients of all speeds and cake height ratios of all cycles for the cream soup concentrates. Combination of measuring techniques (Powder Flow Analyzer, ESEM and Mastersizer) together with Spearman’s Rank Order Correlation, as a method of non-parametric statistics, provides parturient results in characterization of extremely non-homogenous powder mixtures.     

High-throughput SEM preparation of proteinaceaous extracellular matrix

Adhesives of aquatic organisms are of high scientific interest with a view to biomimicry. The visualization of their fine-structure, however, is difficult due to the fragility of the extracellular matrix (ECM). Care must be taken in its preparation for high-resolution SEM. Relating matrix structures to substrate properties demands a high throughput of samples for reliable comparisons. In order to acquaint ourselves with a suitable method we found an easy way to manage the critical steps of preparation for SEM. We show that thin layers of proteinaceous matrix can be satisfactorily prepared by combining freeze-drying and sputtering in a conventional sputter coater after one-step fixation (2.5% glutaraldehyde). The results were superior to CPD.     

An impact of Croatian journals measured by citation analysis from SCI-expanded database in time span 1975–2001

The aim of this research is to gain an insight into international recognition of the STM (Science, Technology, and Medicine) Croatian journals measured by citations in SCI-expanded database. The sample for the research was a citation analysis of 142 journals in time span 1975–2001 for papers published in 1975–1998. More than 90% of those journals are not indexed by SCI-expanded. For the purpose of this research we introduced a new scientometric indicator Normalized number of Citations per 100 Papers (NCP) that allows us direct comparison of the journals from various categories (NCP = 100C/P / IF₁₉₈₉). We chose the year 1989 as a mean value for time span 1975–2001. By citation analysis we established the influence of errors on recognition of Croatian journals and their articles. Obtained results show that an article-to-article link is not found for 32% of cited items. The most frequent type of error is journal title, 37%, which indicates that approximately one third of Croatian journals can not be found when searching by journal title only. Some Croatian journals, even not indexed by SCI-expanded, showed relatively high rank in an impact, i.e. their NCP is higher than 100, and number of citations per paper is higher than 1.     

Face Mask Extraction in Video Sequence

International Journal of Computer Vision - Inspired by the recent development of deep network-based methods in semantic image segmentation, we introduce an end-to-end trainable model for face mask...     

Alcohol dehydrogenase in non‐aqueous media using high‐pressure technologies: reaction set‐up and deactivation determination

BACKGROUND: The demand for enantiomerically pure molecules is growing continuously and biocatalysis is a powerful technique for their production. In this work, the catalyst was an enzyme combined with its coenzyme, NADP. High pressure technology, a second clean technology, was applied as well. Dense gases are promising solvents for biocatalysis. They have been investigated extensively as reaction media for lipase‐catalysed reactions, but seldom for reactions, catalysed with alcohol dehydrogenases, as in this work. RESULT: The production of optically pure R‐1‐phenylethanol from acetophenone was investigated. The NADP‐dependent alcohol dehydrogenase from Lactobacillus brevis (LBADH) was used as a catalyst. The hydrogenation was performed with isopropanol as a co‐substrate in different conditions: dense propane with LBADH and NADP co‐immobilized on glass beads and in the biphasic system water/dense propane. The obtained R‐1‐phenylethanol was enantiopure. The conversions were up to 90%. Deactivation of LBADH was also measured in these media. CONCLUSION: Protocols were successfully developed for the testing of alcohol dehydrogenase activity in dense gases. Enantioselectivity of LBADH is excellent in those media but it deactivated quickly. An LBADH‐catalysed reaction was performed in a dense gas for the first time. Copyright © 2010 Society of Chemical Industry