Water remediation by micelle-clay system: case study for tetracycline and sulfonamide antibiotics

Removal of tetracycline and sulfonamide antibiotics from water by micelles pre-adsorbed on montmorillonite was studied. Micelles of benzyldimethylhexadecylammonium (BDMHDA) were used. Batch experiments demonstrated that the micelle-clay complexes (1% w/w) removed 96-99.9% of antibiotics from their water solutions containing from 5 to 50 mg/L of pharmaceuticals. Column filters (25 cm) made of a mixture of quartz sand and BDMHDA micelle-clay complex at 100:1 w/w ratio removed 94-99.9% of above pharmaceuticals from initial solutions containing 10mg/L and 89% of sulfamethizole from an initial solution containing 10 microg/L of this antibiotic. These filters were also very efficient in the removal of antibiotics in the presence of dissolved soil organic matter removing 89-99% of tetracycline and sulfamethizol from initial solutions containing 10 mg/L of antibiotic in the presence of 8 mg/L of humic acid, or 9 mg/L of fulvic acid. These data indicate that micelle-clay complexes are very efficient for water purification from tetracycline and sulfonamide antibiotics.     

Oxidative Damage in Sporadic Colorectal Cancer: Molecular Mapping of Base Excision Repair Glycosylases MUTYH and hOGG1 in Colorectal Cancer Patients

Oxidative stress, oxidative DNA damage and resulting mutations play a role in colorectal carcinogenesis. Impaired equilibrium between DNA damage formation, antioxidant status, and DNA repair capacity is responsible for the accumulation of genetic mutations and genomic instability. The lesion-specific DNA glycosylases, e.g., hOGG1 and MUTYH, initiate the repair of oxidative DNA damage. Hereditary syndromes (MUTYH-associated polyposis, NTHL1-associated tumor syndrome) with germline mutations causing a loss-of-function in base excision repair glycosylases, serve as straight forward evidence on the role of oxidative DNA damage and its repair. Altered or inhibited function of above glycosylases result in an accumulation of oxidative DNA damage and contribute to the adenoma-adenocarcinoma transition. Oxidative DNA damage, unless repaired, often gives rise G:C > T:A mutations in tumor suppressor genes and proto-oncogenes with subsequent occurrence of chromosomal copy-neutral loss of heterozygosity. For instance, G>T transversions in position c.34 of a KRAS gene serves as a pre-screening tool for MUTYH-associated polyposis diagnosis. Since sporadic colorectal cancer represents more complex and heterogenous disease, the situation is more complicated. In the present study we focused on the roles of base excision repair glycosylases (hOGG1, MUTYH) in colorectal cancer patients by investigating tumor and adjacent mucosa tissues. Although we found downregulation of both glycosylases and significantly lower expression of hOGG1 in tumor tissues, accompanied with G>T mutations in KRAS gene, oxidative DNA damage and its repair cannot solely explain the onset of sporadic colorectal cancer. In this respect, other factors (especially microenvironment) per se or in combination with oxidative DNA damage warrant further attention. Base excision repair characteristics determined in colorectal cancer tissues and their association with disease prognosis have been discussed as well.     

Discovery of Long Non-Coding RNA MALAT1 Amplification in Precancerous Colorectal Lesions

A colorectal adenoma, an aberrantly growing tissue, arises from the intestinal epithelium and is considered as precursor of colorectal cancer (CRC). In this study, we investigated structural and numerical chromosomal aberrations in adenomas, hypothesizing that chromosomal instability (CIN) occurs early in adenomas. We applied array comparative genomic hybridization (aCGH) to fresh frozen colorectal adenomas and their adjacent mucosa from 16 patients who underwent colonoscopy examination. In our study, histologically similar colorectal adenomas showed wide variability in chromosomal instability. Based on the obtained results, we further stratified patients into four distinct groups. The first group showed the gain of MALAT1 and TALAM1, long non-coding RNAs (lncRNAs). The second group involved patients with numerous microdeletions. The third group consisted of patients with a disrupted karyotype. The fourth group of patients did not show any CIN in adenomas. Overall, we identified frequent losses in genes, such as TSC2, COL1A1, NOTCH1, MIR4673, and GNAS, and gene gain containing MALAT1 and TALAM1. Since long non-coding RNA MALAT1 is associated with cancer cell metastasis and migration, its gene amplification represents an important event for adenoma development.     

GENETIC CONTROL OF THIAMINE EXCRETION AND OF ITS SUPPRESSION IN SACCHAROMYCES CEREVISIAE

Three non-linked loci were found to be involved in thiamine excretion in Saccharomyces cerevisiae, i.e. thi2 which is complementary with thi3 and thi4, the latter two being substitutable mutually but acting also together. Mutation thi3 was present already in strain Nα, which produced relatively high frequencies of excreters after UV treatment. Non-excreting ‘revertants’ of unstable excreters derived from another haploid strain contained recessive mutation thi2, so that mutation thi3 can be substituted also by the metabolic or physiological disorders ruling after UV treatment. Mutations thi2 were found also in all 43 analysed stable excreting mutants obtained by UV treatment of strain Nα which indicates that they are either inevitable for the excretion or are specifically selected by the selection method used. At least one suppressor locus of thiamine excretion was present in that strain of S. cerevisiae, which did not produce thiamine excreters after UV treatment in spite of its ability to synthetise thiamine.     

Effect of clay treatment on structure and mechanical behavior of elastomer-containing polyamide 6 nanocomposite

The effect of clay organophilization on mechanical behavior and structure of PA6/EPR blends was studied. It has been shown that the modification of clay affected simultaneously the degree of PA6 matrix reinforcement, size and structure of dispersed EPR. The localization of clay with less polar treatment in the interfacial area brought an important new effect consisting intensification of toughening effect of dispersed elastomer by formation of “core-shell” particles. Basic aspects governing formation of this advantageous structure are reported.The best balanced mechanical behavior was achieved when combining two differently modified clays, whereas the clay with less polar treatment is preblended with EPR. In this way, a high degree of matrix reinforcement (exfoliation of clay with more polar treatment) was combined with favorable size and structure of dispersed EPR phase. Additionally, at lower clay content, synergy between clay and elastomer phase, monitoring itself by enhancement of toughness, was found.     

The nature of the synergistic effect of binary tetralin-alcohol solvents in Kansk-Achinsk brown coal liquefaction

Kansk-Achinsk brown coal hydrogenation and swelling in tetralin, in low molecular alcohols, in other solvents and in binary mixtures were studied. Tetralin was found to be the most effective liquefaction solvent, but methanol and ethanol were the active ones in coal swelling. Synergistic effects were observed when the mixtures of tetralin and methanol or ethanol were used for liquefaction and swelling. The effect of binary solvents was shown to be due to the ability of alcohol components to cause brown coal to swell improving the availability of the fragments of coal matter for the reactive hydrogen donor tetralin molecules.     

A weighted voting framework for classifiers ensembles

We propose a probabilistic framework for classifier combination, which gives rigorous optimality conditions (minimum classification error) for four combination methods: majority vote, weighted majority vote, recall combiner and the naive Bayes combiner. The framework is based on two assumptions: class-conditional independence of the classifier outputs and an assumption about the individual accuracies. The four combiners are derived subsequently from one another, by progressively relaxing and then eliminating the second assumption. In parallel, the number of the trainable parameters increases from one combiner to the next. Simulation studies reveal that if the parameter estimates are accurate and the first assumption is satisfied, the order of preference of the combiners is: naive Bayes, recall, weighted majority and majority. By inducing label noise, we expose a caveat coming from the stability-plasticity dilemma. Experimental results with 73 benchmark data sets reveal that there is no definitive best combiner among the four candidates, giving a slight preference to naive Bayes. This combiner was better for problems with a large number of fairly balanced classes while weighted majority vote was better for problems with a small number of unbalanced classes.     

Corrosivity of atmosphere toward structural metals and mapping the continental Russian territory

ABSTRACT

The corrosivity of atmosphere in the continental territory of Russia toward carbon steel, zinc, copper and aluminium was determined and estimated. The atmosphere corrosivity was determined from experimental data on first-year corrosion losses in representative test locations. The atmosphere corrosivity was estimated using first-year corrosion losses of structural materials calculated by means of dose–response functions: new ones (DRF^N) and those presented in ISO 9223 (DRF^S). Estimation of atmosphere corrosivity in the Russian Federation (RF) territory was performed using the data bank of the Institute of physical chemistry and electrochemistry of the Russian Academy of Sciences containing long-term annual average meteorological atmosphere parameters. The mapping of RF continental territory by categories of atmosphere corrosivity is presented. The atmosphere corrosivities estimated by DRF^N and DRF^S for each metal are compared. It has been shown that DRF^N provides more reliable atmosphere corrosivity estimates.     

A Dual-Color Tyr-FISH Method for Visualizing Genes/Markers on Plant Chromosomes to Create Integrated Genetic and Cytogenetic Maps

In situ imaging of molecular markers on a physical chromosome is an indispensable tool for refining genetic maps and validation genome assembly at the chromosomal level. Despite the tremendous progress in genome sequencing, the plant genome assembly at the chromosome level remains a challenge. Recently developed optical and Hi-C mapping are aimed at assistance in genome assembly. For high confidence in the genome assembly at chromosome level, more independent approaches are required. The present study is aimed at refining an ultrasensitive Tyr-FISH technique and developing a reliable and simple method of in situ mapping of a short unique DNA sequences on plant chromosomes. We have carefully analyzed the critical steps of the Tyr-FISH to find out the reasons behind the flaws of this technique. The accurate visualization of markers/genes appeared to be significantly dependent on the means of chromosome slide preparation, probe design and labeling, and high stringency washing. Appropriate adjustment of these steps allowed us to detect a short DNA sequence of 1.6 Kb with a frequency of 51.6%. Based on our results, we developed a more reliable and simple protocol for dual-color Tyr-FISH visualization of unique short DNA sequences on plant chromosomes. This new protocol can allow for more accurate determination of the physical distance between markers and can be applied for faster integration of genetic and cytogenetic maps.     

Effect of Dispersity and Porous Structure of TiO2 Nanopowders on Photocatalytic Destruction of Azodyes in Aqueous Solutions

Photocatalytic activity of TiO2 nanopowders of anatase modification with various particle sizes and specific surface areas has been studied in the process of photocatalytic decolorization of aqueous solutions of methylene blue and direct blue 2C azodyes. By means of scanning electron microscopy and low-temperature N2 adsorption method, it was found that TiO2 nanopowders have the particles size of 5-120 nm with the specific surface area of 15-120 m2·g^-1. The used TiO2 samples are characterized by mesoporous structures with average pore size of 4.3-14.9 nm. The photocatalytic activity of TiO2 was evaluated via decolorization of azodyes solutions. It was shown that the efficiency of decolorization symbatically changes with the dye adsorption value on TiO2 surface and the degree of decolorization rises when the surface area of TiO2 nanopowders increases. It was found that TiO2 photocatalytic activity essentially depends on adsorption interactions between the dye molecules and catalytic active centers on TiO2 surface, and these interactions, in turn, are greatly affected by pH of the solution.