Study on the new bone cement based on calcium sulfate and Mg,CO3 doped hydroxyapatite

In order to improve some features of bone substitutes the new self-setting composite-type implant material based on Mg²⁺/CO₃^2? co-substituted hydroxyapatite (Mg-CHA) and calcium sulfate hemihydrate (CSH) was developed. Synthetic hydroxyapatites doped with small amounts of additives found in natural bone (e.g. Mg²⁺ and CO₃^2?) are regarded as promising components of calcium phosphate bone cements (CPCs). The CPCs, now available on the market, due to low resorption rate are too stable to permit material degradation and are slowly replaced by the newly formed bone. To improve cement resorption we used calcium sulfate which is a well-known biodegradable and biocompatible bone defect filler. Combining properties of Mg-CHA and CSH allowed developing a new, promising, easy shapeable implant material with high potential for bone regeneration.     

Flame-spraying synthesis of aluminate glasses in the Al2O3–La2O3 system

The paper deals with the synthesis and characterisation of binary aluminate glasses in the La₂O₃–Al₂O₃ system with Al₂O₃ contents changing between 74.6 and 86.9 mol% (48–65 wt.%), and of ternary glasses with 75.7 mol% Al₂O₃ doped with 1 mol% of Nd₂O₃ or Er₂O₃. Six binary and two ternary compositions were prepared. Flame synthesis facilitated the preparation of X-ray amorphous microspheres in the systems with 58 wt.% Al₂O₃, and with eutectic composition in the pseudobinary LaAlO₃–LaAl₁₁O₁₈ system doped with Er. Other systems contained low fractions of crystalline LaAlO₃ perovskite, regardless of the composition. The diameter of prepared microspheres ranged between 2 and 10 μm. They were transparent for visible light, as well as in the IR wavenumber range from 1300 to 4000 cm^?1.     

Theoretical Aspects Of The Kinetics Of Competitive First Reactions Of Ozone In The O3/H2O2 And O3/UV Oxidation Processes

Kinetics of competition between the ozone direct reaction with compounds in water, ozone-hydroperoxide ion reaction leading to free radicals in the O₃/H₂O₂ process, and the photolysis of ozone in the O₃/UV process are discussed in terms of diffusion and reaction times to establish conditions for these reactions to be competitive. Film theory and chemical kinetic concepts then are applied to estimate initial rates of ozone absorption and consumption, removal rates of compounds present in water, and the importance of the radical oxidation path versus direct ozone and/or photolysis reactions.     

Stabilization of Telomeric I‐Motif Structures by (2′S)‐2′‐Deoxy‐2′‐C‐Methylcytidine Residues

G‐quadruplexes and i‐motifs are tetraplex structures present in telomeres and the promoter regions of oncogenes. The possibility of producing nanodevices with pH‐sensitive functions has triggered interest in modified oligonucleotides with improved structural properties. We synthesized C‐rich oligonucleotides carrying conformationally restricted (2′S)‐2′‐deoxy‐2′‐C‐methyl‐cytidine units. The effect of this modified nucleoside on the stability of intramolecular i‐motifs from the vertebrate telomere was investigated by UV, CD, and NMR spectroscopy. The replacement of selected positions of the C‐core with C‐modified residues induced the formation of stable intercalated tetraplexes at near‐neutral pH. This study demonstrates the possibility of enhancing the stability of the i‐motif by chemical modification.     

Characterization of Biomimetic Cofactors According to Stability,Redox Potentials,and Enzymatic Conversion by NADH Oxidase from Lactobacillus pentosus

Oxidoreductases are attractive biocatalysts that convert achiral substrates into products of higher value, but they are also for the most part dependent on nicotinamide cofactors. Recently, biomimetic nicotinamide derivatives have received attention as less costly alternatives to natural cofactors. However, recycling of biomimetics is still challenging because there are only limited opportunities. Here, we have characterized various biomimetic cofactors with regard to stability and redox potentials to find the best alternative to natural cofactors. Further, the cofactor spectrum of NADH oxidase from Lactobacillus pentosus (LpNox) could be expanded, and the enzymatic activity was also compared to activities with different small‐molecule catalysts. As a result, we succeeded in identifying several strategies for regeneration of oxidized biomimetics.     

An adaptive color similarity function suitable for image segmentation and its numerical evaluation

In this article, we present an adaptive color similarity function defined in a modified hue‐saturation‐intensity color space, which can be used directly as a metric to obtain pixel‐wise segmentation of color images among other applications. The color information of every pixel is integrated as a unit by an adaptive similarity function thus avoiding color information scattering. As a direct application we present an efficient interactive, supervised color segmentation method with linear complexity respect to the number of pixels of the input image. The process has three steps: (1) Manual selection of few pixels in a sample of the color to be segmented. (2) Automatic generation of the so called color similarity image (CSI), which is a gray level image with all the gray level tonalities associated with the selected color. (3) Automatic threshold of the CSI to obtain the final segmentation. The proposed technique is direct, simple and computationally inexpensive. The evaluation of the efficiency of the color segmentation method is presented showing good performance in all cases of study. A comparative study is made between the behavior of the proposed method and two comparable segmentation techniques in color images using (1) the Euclidean metric of the a* and b* color channels rejecting L* and (2) a probabilistic approach on a* and b* in the CIE L*a*b* color space. Our testing system can be used either to explore the behavior of a similarity function (or metric) in different color spaces or to explore different metrics (or similarity functions) in the same color space. It was obtained from the results that the color parameters a* and b* are not independent of the luminance parameter L* as one might initially assume in the CIE L*a*b* color space. We show that our solution improves the quality of the proposed color segmentation technique and its quick result is significant with respect to other solutions found in the literature. The method also gives a good performance in low chromaticity, gray level and low contrast images. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 156–172, 2017     

Reduction of Captan,Boscalid and Pyraclostrobin Residues on Apples Using Water Only,Gaseous Ozone,and Ozone Aqueous Solution

Intensive use of plant protection products in modern agriculture and horticulture often results in increasing residue levels of active ingredients of plant protection products in fruits and vegetables. Even if the maximum residue levels are not exceeded, the synergic effects of various compounds may have a serious impact on consumers' health. In particular, more sensitive consumer groups, e.g., children, may be affected. Therefore, it is important to develop an effective method that could be utilized for reduction of pesticide residue levels in food products of plant origin. In this work, possible application of ozone to reduce pesticide residue levels in apples has been investigated. The fruits were treated with ozone in gaseous state, in ozonized water, and in water alone, which was used for rinsing the fruits. The experiments included tests on apples that were subjected to a protection program using captan, boscalid and pyraclostrobin. The ozonized water and treatment with a gaseous ozone were found to be not more efficient in reducing the pesticide content on the fruits than simple washing procedures, e.g., 81–95% reduction of captan residue or 40–67% reduction of boscalid residue and 20–42% reduction of pyraclostrobin residue. Still, ozonation of water used for rinsing prevented fruits from consecutive contamination by pesticide residues present in water after several rinsing cycles. It was proven that application of ozonation process as a part of post-harvest treatment of apples may be beneficial for the fruit quality.     

Degradation of Phenolic Compounds in Aqueous Sucrose Solutions by Ozonation

The sugar industry is concerned with color formation due to the oxidation of phenolic compounds in the presence of carbohydrates. In this study, we investigated the ozonation of a mixture of five phenolic compounds in water and aqueous sucrose solution: p-coumaric (p-COU), caffeic (CAF), syringic (SYR), and chlorogenic (CHO) acids, as well as the flavonoid quercetin (QUE). The experiments were carried out in a 3-L glass reactor with magnetic stirring and a diffuser plate at the bottom to feed the ozone-oxygen gas mixture. Initial solution concentrations of 5 mg L?1 of each acid, 15 mg L?1 of quercetin, and 40 g L?1 of sucrose were used. The degradation of phenolic compounds followed apparent first-order kinetics, with rate constants and percent removals decreasing in the presence of sucrose. In water, average consumed ozone dosages of 10.4 and 18.7 mg L?1 were necessary for 50% and 90% removals, respectively, for CHO, CAF, and p-COU; for QUE they were slightly higher (13.9 and 20.5 mg L?1, respectively). At a consumed dosage of 20.8 mg O3 L?1, more than 99% removal was obtained for CHO, CAF, and p-COU, while 96.2% was achieved for SYR. In contrast, QUE revealed to be more recalcitrant during ozonation in the absence of sucrose, with only 70% removal at the highest consumed O3 dosage. The consumed ozone dosages for 50% and 90% removals were higher for CHO, CAF, and p-COU in aqueous sucrose solution, which may impact ozone consumption during real sugarcane juice treatment. Sucrose and t-butanol were the main influential parameters that significantly affected the total amount of phenolic compounds degraded.