Changes in the contents of mono-, di- and oligosaccharides in leek plants stored in cold room

The aim of this work is to present the results of the analysis of composition of mono-, di- and oligosaccharides, including the content of fructooligosaccharides as well as rafinose, stachyose in pseudo stalk of leek plants of the following cultivars: Shelton F1, Belton F1 and Parton F1. Leek plants were stored in cold room at the temperature 0 °C and relative humidity around 98% in the period from December to May. Fructose, glucose, saccharose, fructooligosaccharides (FOS) as well as α-galactosides were determined with the HPLC method with the application of water-alcohol extracts. It was shown that some of the studied parameters have changed during storage, i.e., the glucose content increased from 4.4 ± 0.3 to 16.2 ± 1.6, fructose from 4.7 ± 0.2 to 23.8 ± 0.4, saccharose from 5.1 ± 0.7 to 18.7 ± 0.1, depending on the cultivar and the storage period. The largest increase in the content of fructose and glucose took place between 60th and 90th day of storage which testifies to intensive hydrolysis of fructans. Leek cv. Parton F1 was characterised by the largest content of fructans and the lowest susceptibility to hydrolysis. The amount of kestose, nystose and rafinose after the period of storage changed from 0.3 ± 0.0 to 0.9 ± 0.2, 0.5 ± 0.1 to 1.8 ± 0.1, 0.8 ± 0.1 to 1.8 ± 0.2 g/100 g of dry mass, respectively. The content of stachyose, in turn, remained at a constant level and amounts to around 0.5 g/100 g of dry mass. Leek plants kept in typical refrigeration conditions are characterised by good durability and constitute a valuable merchandise. However, due to ongoing hydrolysis processes, the content of prebiotic substances decreased what lowered the health-promoting value.     

Synthesis of novel tricalcium phosphate-bioactive glass composite and functionalization with rhBMP-2

A functionalization is required for calcium phosphate-based bone substitute materials to achieve an entire bone remodeling. In this study it was hypothesized that a tailored composite of tricalcium phosphate and a bioactive glass can be loaded sufficiently with rhBMP-2 for functionalization. A composite of 40 wt% tricalcium phosphate and 60 wt% bioactive glass resulted in two crystalline phases, wollastonite and rhenanite after sintering. SEM analysis of the composite’s surface revealed a spongious bone-like morphology after treatment with different acids. RhBMP-2 was immobilized non-covalently by treating with chrome sulfuric acid (CSA) and 3-aminopropyltriethoxysilane (APS) and covalently by treating with CSA/APS, and additionally with 1,1′-carbonyldiimidazole. It was proved that samples containing non-covalently immobilized rhBMP-2 on the surface exhibit significant biological activity in contrast to the samples with covalently bound protein on the surface. We conclude that a tailored composite of tricalcium phosphate and bioactive glass can be loaded sufficiently with BMP-2.     

Interaction of Cationic Carbosilane Dendrimers and Their siRNA Complexes with MCF-7 Cells

The application of siRNA in gene therapy is mainly limited because of the problems with its transport into cells. Utilization of cationic dendrimers as siRNA carriers seems to be a promising solution in overcoming these issues, due to their positive charge and ability to penetrate cell membranes. The following two types of carbosilane dendrimers were examined: CBD-1 and CBD-2. Dendrimers were complexed with pro-apoptotic siRNA (Mcl-1 and Bcl-2) and the complexes were characterized by measuring their zeta potential, circular dichroism and fluorescence of ethidium bromide associated with dendrimers. CBD-2/siRNA complexes were also examined by agarose gel electrophoresis. Both dendrimers form complexes with siRNA. Moreover, the cellular uptake and influence on the cell viability of the dendrimers and dendriplexes were evaluated using microscopic methods and XTT assay on MCF-7 cells. Microscopy showed that both dendrimers can transport siRNA into cells; however, a cytotoxicity assay showed differences in the toxicity of these dendrimers.     

Modeling of conductivity in composites with random resistor networks

Composite polymeric electrolytes (CPE) are well known systems in which an improvement in electrical conductivity of the polymer is achieved by the addition of a non-conductive additive (ceramic powders and immiscible polymers). A new class of conductivity models based on the application of the multi-value random resistor networks to the studies of CPE was developed by the authors. The first stage of the simulation is based on the virtual composite sample generation and its transformation into a form of the three-dimensional resistor network. The sample generation can take into account variable material parameters such as average grain diameter, shell thickness as well as their statistical distribution and different dependencies of local shell conductivity on the distance from the grain surface. The second stage of the algorithm is the use of the modified iteration procedure based on Kirkpatrick approach leading to the direct current resistivity of the virtual sample. The presented results were obtained for the matrix size 100 unit × 100 unit × 100 unit (with assumption 1 unit = 1 μm). The dependency of conductivity on the grain filler concentration was studied for varying grain sizes, changing shell thickness as well as for different statistical distributions of these parameters. The obtained results of simulation are in general agreement with the experimental data.     

An integrated analysis of ergonomics and time consumption in Swedish 'craft-type' car disassembly

Car disassembly is at the edge of extensive rationalization due to increased legislative demands for recycling. This study focused on (1) assessing current mechanical exposures (physical work loads) for comparison with future rationalised systems, with particular emphasis on time aspects, (2) analysing disassembly work in terms of time consumption and exposures in constituent tasks as defined by a loss analysis technique, and (3) predicting the consequences of car disassembly rationalisation for mechanical exposures. The study showed that disassembly implied pronounced circulatory loads, and that more walking and higher lumbar peak loads were found than in studies of assembly work. Value-adding tasks comprised 30% of the total working time, and implied higher postural exposures for the head, arm, trunk and wrist, as well as less opportunities to recover, as compared to non-value-adding tasks. Organisational-type rationalization can be expected to increase the time spent in value-adding work, thus increasing local exposures for the average worker, while a concurrent increase in mechanization level might reduce circulatory exposures, the amount of walking, and peak lumbar loads.     

A Photoexcited Porphyrin System as a Biomimetic Catalyst for D-limonene Biotransformation

A photoexcited porphyrin system has been found to be an efficient catalyst for D-limonene biotransformation. The catalyst showed high selectivity in hydroxylation of D-limonene. The best catalyst for limonene biotransformation was 5,10,15,20-Tetraphenylporphyrin (H₂TPP), which gave the highest accumulation of carvone and an unknown product with a verbenone-like mass spectrum. The highest conversion yield of these products was favoured at 1:2 molar ratio of H₂TPP to limonene. Some factors affecting the biotransformation yield were also investigated. Maximal yield of carvone was obtained in the medium containing 90% of the substrate, within the period of 18–36 h. Mechanism involved in limonene biotransformation catalysed by H₂TPP is also discussed.     

Studies on the usefulness of Cucurbita maxima for the production of ready-to-eat dried vegetable snacks with a high carotenoid content

Recent research indicates a beneficial influence of a diet rich in β-carotene on human health. For that reason, experiments were undertaken to process winter squash with a high carotenoid content into ready-to-eat dried snacks. Sensory quality and dietary value of chips and crispy cubes made from different cultivars were investigated.The suitability of winter squash for drying purposes depended mainly on the dry matter content in the raw material. Although all the investigated cultivars can be used for producing chips, obtaining high quality porous cubes requires at least 15% of dry matter. ‘Justynka F1’ emerged as the most suitable cultivar for processing; both chips and cubes produced from its fruits were characterized by a high sensory quality and contained significant amounts of beta-carotene (225- 253 μg g-1). Also, the cultivar ‘Amazonka’ could be considered for the production of chips as it allowed us to obtain a product with a high beta-carotene content (200 μg g-1) and good sensory properties. The dried ready-to-eat crispy vegetable snacks made from the new cultivars of winter squash could be exploited as a novel attractive product with the attractive taste and colour to serve as a valuable source of carotenoids in human diet.     

Brittle‐to‐Ductile Transition in Uniaxial Compression of Silicon Pillars at Room Temperature

Robust nanostructures for future devices will depend increasingly on their reliability. While great strides have been achieved for precisely evaluating electronic, magnetic, photonic, elasticity and strength properties, the same levels for fracture resistance have been lacking. Additionally, one of the self‐limiting features of materials by computational design is the knowledge that the atomistic potential is an appropriate one. A key property in establishing both of these goals is an experimentally‐determined effective surface energy or the work per unit fracture area. The difficulty with this property, which depends on extended defects such as dislocations, is measuring it accurately at the sub‐micrometer scale. In this Full Paper the discovery of an interesting size effect in compression tests on silicon pillars with sub‐micrometer diameters is presented: in uniaxial compression tests, pillars having a diameter exceeding a critical value develop cracks, whereas smaller pillars show ductility comparable to that of metals. The critical diameter is between 310 and 400 nm. To explain this transition a model based on dislocation shielding is proposed. For the first time, a quantitative method for evaluating the fracture toughness of such nanostructures is developed. This leads to the ability to propose plausible mechanisms for dislocation‐mediated fracture behavior in such small volumes.     

Effect of Thermal Treatment on the Photocatalytic Activity in Visible Light of TiO<Subscript>2</Subscript>-W Flame Spray Synthesised Nanopowders

Effect of W doping as well as a thermal treatment on the structural and photocatalytic properties of TiO₂ produced by flame spray synthesis (FSS) were the subject of investigation. Structural properties were studied by means of X-ray diffraction (XRD), BET adsorption isotherm and transmission electron microscopy (TEM). The surface condition was investigated by X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC) and differential thermal and thermogravimetric analysis (DTA-TGA). The photocatalytic properties were studied by optical measurements and photodecomposition of methylene blue under visible irradiation. It was found that the photoactivity in the visible region was enhanced significantly by the W-doping as well as by additional thermal treatment of those nanopowders. The obtained TiO₂-W nanopowders exhibited higher performance under visible light than P25.     

Bimetallic Au–Cu, Ag–Cu/CrAl3O6 Catalysts for Methanol Synthesis

The influence of silver and gold addition on the activity and physicochemical properties of supported Cu/CrAl₃O₆ catalysts was the aim of this work. The reduction of CrAl₃O₆ support shows only one reduction stage attributed to Cr (VI) species reduction originating from previously oxidized binary oxide. Supported copper catalysts reduce in one or two stages depending on copper concentration representing the reduction of copper oxide—CuO, copper oxide chemically combined with Cr(III) oxide as copper chromite—CuCr₂O₄ and Cr(VI) species originating from surface chromate ions CrO₄ ^2?. Additionally, the introduction of silver into supported copper catalysts Cu/CrAl₃O₆ can led to the appearance of silver chromate phase. XRD investigations of support CrAl₃O₆ alone, supported copper and gold and silver promoted copper supported catalysts calcined at 400, 700 and 900 °C indicated the presence of highly amorphous alumina γ-Al₂O₃ like structure network in which some of cationic locations of aluminum were occupied by chromium atoms and small quantities of α-Cr₂O₃ phase. Additionally, for copper, silver–copper, and gold–copper supported catalysts the following oxide phases were distinguished: monometallic oxides CuO, Ag₂O, binary oxides CuAl₂O₄, Ag₂CrO₄, CuCr₂O₄ and even ternary oxide CuAlCrO₄. In the case of gold promoted copper supported catalysts metallic gold phase was detected. Activity tests carried out for these catalysts show that the most active was 20 wt.% Cu/CrAl₃O₆ catalyst. Promotion of copper catalysts by silver improves the activity in methanol synthesis, what can be assigned to silver chromate formation. The analogical gold chromate like formation was not confirmed.