Water quality and diatom communities in two catalan rivers (N.E. Spain)

Benthic diatom assemblages have been used to evaluate the water quality of two rivers subjected to marked human influences. These rivers, the Llobregat and the Ter, are located in N.E. Spain, and supply water for industrial, agricultural and urban requirements of roughly three million people. The diatom communities in the headwaters are similar in both rivers (Achnanthes minutissima, Cymbella ventricosa, Gomphonema anguslatum). Species of Navicula, Nitzschia and Gomphonema develop in the middle reaches of both rivers when not disrupted by extraneous factors. In the river Ter significant pollution modifies this community and Nitzschia palea, Nitzschia gandersheimiensis and Gomphonema parvulum appear as the most tolerant species. In the Llobregat, the pollution from the salt mine operations also modifies the diatom assemblage and Nitzschia frustulum, Surirella ovata, Navicula atomus are the most abundant species. Reservoirs in the river Ter improve the quality of water and a community of Fragilaria sp. pl. becomes dominant downstream.     

Failure Resistance of the Historic Stone Bridge Structure of Charles Bridge. I: Susceptibility to Nonstress Effects

The monitoring of deformations of the stone structure of Charles Bridge in Prague proved the gravity and relevance of nonstress effects (temperature, moisture content) on cyclic deformations and permanent strain accompanied by a gradual disintegration of its stone masonry, growing tilt of the breast walls, and development of cracks in the masonry of the stone bridge structure. Each deformation cycle is accompanied by a gradual growth in permanent deformations. The “unmanifested” primary deformation due to, e.g., a temperature change causes a mechanical state of tension, and it is mainly the tensile stresses thus arising that contribute to the development of tensile cracks in the stone masonry.     

Multifunctional Gadolinium‐Doped Mesoporous TiO2 Nanobeads: Photoluminescence,Enhanced Spin Relaxation,and Reactive Oxygen Species Photogeneration,Beneficial for Cancer Diagnosis and Treatment

Materials with controllable multifunctional abilities for optical imaging (OI) and magnetic resonant imaging (MRI) that also can be used in photodynamic therapy are very interesting for future applications. Mesoporous TiO₂ sub‐micrometer particles are doped with gadolinium to improve photoluminescence functionality and spin relaxation for MRI, with the added benefit of enhanced generation of reactive oxygen species (ROS). The Gd‐doped TiO₂ exhibits red emission at 637 nm that is beneficial for OI and significantly improves MRI relaxation times, with a beneficial decrease in spin–lattice and spin–spin relaxation times. Density functional theory calculations show that Gd³⁺ ions introduce impurity energy levels inside the bandgap of anatase TiO₂, and also create dipoles that are beneficial for charge separation and decreased electron–hole recombination in the doped lattice. The Gd‐doped TiO₂ nanobeads (NBs) show enhanced ability for ROS monitored via ^?OH radical photogeneration, in comparison with undoped TiO₂ nanobeads and TiO₂ P25, for Gd‐doping up to 10%. Cellular internalization and biocompatibility of TiO₂@x Gd NBs are tested in vitro on MG‐63 human osteosarcoma cells, showing full biocompatibility. After photoactivation of the particles, anticancer trace by means of ROS photogeneration is observed just after 3 min irradiation.     

Notes on the Asymmetric Hydrogenation of Methyl Acetoacetate in Neoteric Solvents

Asymmetric hydrogenation of methyl acetoacetate to methyl (R)-3-hydroxybutyrate by [(R)- RuCl(binap)(p-cymen)]Cl has been studied in methanol-ionic liquid and methanol- dense CO₂ solvent systems. The ionic pairs triethylhexylammonium and 1-methylimidazolium with bis(trifluoromethane sulfonyl) imide and hexafluorophosphates were used. The role of ionic pairs on the kinetic parameters and (enantio)selectivity has been demonstrated. Although the CO₂ expanded methanol system suffered from a reduction in both reaction rate and product selectivity, this changed in the presence of water. The high selectivity of the optimized methanol-CO₂-water-halide system was designed as a consequence of observed additive effects.     

Einfluss der Feuchtebeladung bei der Druckbeanspruchung von Granulaten

The material behavior of γ‐Al₂O₃‐, zeolite 4A‐ und sodium benzoate granules at compression has been experimentally studied. The material behavior has been found to be dominant elastic, elastic‐plastic and dominant plastic. Additionally, the influence of moisture content on the material behavior has been investigated. The force‐displacement curves have been approximated using suitable mechanical models.     

A Novel Insight into the Cardiotoxicity of Antineoplastic Drug Doxorubicin

Doxorubicin is a commonly used antineoplastic agent in the treatment of many types of cancer. Little is known about the interactions of doxorubicin with cardiac biomolecules. Serious cardiotoxicity including dilated cardiomyopathy often resulting in a fatal congestive heart failure may occur as a consequence of chemotherapy with doxorubicin. The purpose of this study was to determine the effect of exposure to doxorubicin on the changes in major amino acids in tissue of cardiac muscle (proline, taurine, glutamic acid, arginine, aspartic acid, leucine, glycine, valine, alanine, isoleucine, threonine, lysine and serine). An in vitro interaction study was performed as a comparison of amino acid profiles in heart tissue before and after application of doxorubicin. We found that doxorubicin directly influences myocardial amino acid representation even at low concentrations. In addition, we performed an interaction study that resulted in the determination of breaking points for each of analyzed amino acids. Lysine, arginine, β-alanine, valine and serine were determined as the most sensitive amino acids. Additionally we compared amino acid profiles of myocardium before and after exposure to doxorubicin. The amount of amino acids after interaction with doxorubicin was significantly reduced (p = 0.05). This fact points at an ability of doxorubicin to induce changes in quantitative composition of amino acids in myocardium. Moreover, this confirms that the interactions between doxorubicin and amino acids may act as another factor most likely responsible for adverse effects of doxorubicin on myocardium.     

Apoferritin Modified Magnetic Particles as Doxorubicin Carriers for Anticancer Drug Delivery

Magnetic particle mediated transport in combination with nanomaterial based drug carrier has a great potential for targeted cancer therapy. In this study, doxorubicin encapsulation into the apoferritin and its conjugation with magnetic particles was investigated by capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). The quantification of encapsulated doxorubicin was performed by fluorescence spectroscopy and compared to CE-LIF. Moreover, the significant enhancement of the doxorubicin signal was observed by addition of methanol into the sample solution.     

Multiple Compression of Moist Spherical Elastic‐Plastic Zeolite 4A Granules

The compression, deformation and material behavior of moist spherical elastic‐plastic zeolite 4A granules under multiple stressing conditions at unique and random contacts were experimentally studied with the help of uniaxial diametrical compression tests. The force‐displacement curves were approximated and the coefficient of restitution was determined using appropriate mechanical models from literature. The phenomenon of cyclic hardening was studied and the critical number of cycles required to reach fracture was determined. Furthermore, the influence of particle size and moisture content on the material behavior at cyclic loading, the coefficient of restitution, and the critical number of cycles required to reach fracture were investigated.     

Untersuchung des Einflusses der Beanspruchungsgeschwindigkeit auf das Deformations‐ und Bruchverhalten von Weizenkörnern

Compression tests of deformation and fracture behavior of wheat grains were carried out at different loading rates that varied from 0.02 to 0.11 mm s^–1. The contact model originally developed for the spherical particles was adapted to describe the deformation and fracture behavior of elliptical wheat grains. The distributions of basic fracture parameters of wheat grains such as fracture force, fracture strength, fracture energy, and fracture displacement were fitted with normal distribution function.     

Optimization of a Continuous Precipitation Process to Produce Nanoscale BaSO4

The effect of supersaturation, reaction temperature, and mixing intensity on particle size was investigated. Sterical stabilization of barium sulfate suspensions was applied to prevent formation of agglomerates. This allowed a reactant ratio of 1:1, thus maximizing product yield. The local supersaturation is strongly affected by the mixing intensity that can be characterized by Reynolds numbers. The significant decrease in particle size was observed by increasing the Reynolds number from 600 to 8000. A higher reactant concentration leads to a higher degree of supersaturation, and finer particles are precipitated. The particle size can be reduced with increasing reactant concentration. The degree of supersaturation increases with temperature reduction, i.e., the particle size will be reduced at low temperature. In addition, nucleation and growth kinetics are changed in a way that reduces the particle size. The optimized lab‐scale process is capable of producing over 1 kg h^–1 of nanoscaled BaSO₄ with a median diameter of 75 nm.