Studying the effect of modifying additives on the hydration and hardening of cement composites for 3D printing

The development and application of multicomponent multifunctional additives for cement composites is an important research area since the use of such additives allows controlling both the rheological properties of fresh mixtures and the physical and mechanical properties of the hardened composite. In our study, we used several additives, including metakaolin and xanthan gum together with tetrapotassium pyrophosphate and a SiO2 based complex additive, to modify cementitious sand-based materials. We studied the peculiarities of the influence of these additives on the technological characteristics of mixtures (plasticity and shape retention) and the processes of setting, hydration, and hardening of the composite materials. The optimal values of plasticity, for stability, acceleration of hardening were demonstrated by sand-based systems modified with a complex nanosized additive and metakaolin. The hydration products in the such systems are mainly formed from low basic hydroxides. Metakaolin also results in the formation of ettringite. These systems demonstrate the optimal time of the beginning of setting and the maximum strength gain of the modified cementitious sand-based materials at 28 days. The optimal ratio of indicators of plasticity and shape retention of cement mixtures and the strength of composites based on them obtained by using the studied additives allows us to recommend using these additives in the innovative technologies for 3D-build printing

Methylation of the BIN1 gene promoter CpG island associated with breast and prostate cancer

<p>Abstract</p> <p>Background</p> <p>Loss of BIN1 tumor suppressor expression is abundant in human cancer and its frequency exceeds that of genetic alterations, suggesting the role of epigenetic regulators (DNA methylation). <it>BIN1 </it>re-expression in the DU145 prostate cancer cell line after 5-aza-2'-deoxycytidine treatment was recently reported but no methylation of the <it>BIN1 </it>promoter CpG island was found in DU145.</p> <p>Methods</p> <p>Methylation-sensitive arbitrarily-primed PCR was used to detect genomic loci abnormally methylated in breast cancer. <it>BIN1 </it>CpG island fragment was identified among the differentially methylated loci as a result of direct sequencing of the methylation-sensitive arbitrarily-primed PCR product and subsequent BLAST alliance. <it>BIN1 </it>CpG island cancer related methylation in breast and prostate cancers was confirmed by bisulphite sequencing and its methylation frequency was evaluated by methylation sensitive PCR. Loss of heterozygosity analysis of the BIN1 region was performed with two introgenic and one closely adjacent extragenic microsatellite markers.<it>BIN1 </it>expression was evaluated by real-time RT-PCR.</p> <p>Results</p> <p>We have identified a 3'-part of <it>BIN1 </it>promoter CpG island among the genomic loci abnormally methylated in breast cancer. The fragment proved to be methylated in 18/99 (18%) and 4/46 (9%) breast and prostate tumors, correspondingly, as well as in MCF7 and T47D breast cancer cell lines, but was never methylated in normal tissues and lymphocytes as well as in DU145 and LNCaP prostate cancer cell lines. The 5'-part of the CpG island revealed no methylation in all samples tested. <it>BIN1 </it>expression losses were detected in MCF7 and T47D cells and were characteristic of primary breast tumors (10/13; 77%), while loss of heterozygosity was a rare event in tissue samples (2/22 informative cases; 9%) and was ruled out for MCF7.</p> <p>Conclusion</p> <p><it>BIN1 </it>promoter CpG island is composed of two parts differing drastically in the methylation patterns in cancer. This appears to be a common feature of cancer related genes and demands further functional significance exploration. Although we have found no evidence of the functional role of such a non-core methylation in <it>BIN1 </it>expression regulation, our data do not altogether rule this possibility out.</p

Sensitivity to Antimicrobial Drugs of Pseudomonas Aeruginosa Extreme-Resistant Strains Isolated in the Major Hospitals of Central Kazakhstan

AIM: The article presents the current data on the sensitivity of the main 37 strains of eXtremaly Drugs Resistance (XDR) category to anti-pseudomonas drugs.MATERIAL AND METHODS: The strains were collected during the prospective multicenter study in large multidisciplinary hospitals of Central Kazakhstan. Susceptibility to antimicrobial drugs was carried out by disk method and the serial dilution method with the interpretation of the results according to EUCAST criteria. Detection of carbapenemases gene of VIM, IMP, NDM and GES classes was carried out by PCR method using the commercial kits.RESULTS: All identified carbapenemases were sorted to VIM class and accounted for 63.64%. Resistance to aminoglycoside drugs exceeded 80%. All the strains were susceptible to polymyxin.CONCLUSION: Thus, at the present stage the circulation of P. aeruginosa strains of XDR category continues in major hospitals in Kazakhstan. The strains remain sensitiveness only to polymyxin

Formality theorems for Hochschild complexes and their applications

We give a popular introduction to formality theorems for Hochschild complexes and their applications. We review some of the recent results and prove that the truncated Hochschild cochain complex of a polynomial algebra is non-formal.Comment: Submitted to proceedings of Poisson 200

2D “Soap”-Assembly of Nanoparticles via Colloid-Induced Condensation of Mixed Langmuir Monolayers of Fatty Surfactants

We describe a new type of colloidal 2D gels formed in mixed Langmuir monolayers of stearic acid and octadecylamine on a surface of gold hydrosol. The adsorption of gold nanoparticles on the mixed monolayer led to an increase of interactions between oppositely charged surfactants giving a “soap” of mixed fatty salt. The observed effect is equivalent to a virtual “cooling” of floating monolayer, which undergoes rapid condensation on a surface of aqueous colloid. The consequent shrinking and rearrangement of the monolayer resulted in aggregation of nanoparticles into colloidal 2D “soap”-gels, which represented arrested colloidal phases within nonadsorbing organic medium. When sequentially deposited onto solids by Langmuir–Blodgett technique, the 2D “soap”-gels separated into organic and colloidal phases and gave dendrite-like bilateral organic crystallites coated with gold nanoparticles. The reported colloidal “soap”-assembly can offer a new opportunity to design 2D colloidal systems of widely variable chemistry and structures

Draft genomes of Enterococcus faecium strains isolated from human feces before and after eradication therapy against Helicobacter pylori

The abundance of Enterococci in the human intestinal microbiota environment is usually < 0.1% of the total bacterial fraction. The multiple resistance to antibiotics of the opportunistic Enterococcus spp. is alarming for the world medical community because of their high prevalence among clinically significant strains of microorganisms. Enterococci are able to collect different mobile genetic elements and transmit resistance to antibiotics to wide range of Gram-positive and Gram-negative species of microorganisms, including the transmission of vancomycin resistance to methicillin-resistant strains of Staphylococcus aureus. The number of infections caused by antibiotics resistant strains of Enterococcus spp. is increasing. Here we present a draft genomes of Enterococcus faecium strains. These strains were isolated from human feces before and after (1 month) Helicobacter pylori eradication therapy. The samples were subject to whole-genome sequencing using Illumina HiSeq. 2500 platform. The data is available at NCBI https://www.ncbi.nlm.nih.gov/bioproject/PRJNA412824

Genome analysis of E. coli isolated from Crohn’s disease patients

Abstract Background Escherichia coli (E. coli) has been increasingly implicated in the pathogenesis of Crohn’s disease (CD). The phylogeny of E. coli isolated from Crohn’s disease patients (CDEC) was controversial, and while genotyping results suggested heterogeneity, the sequenced strains of E. coli from CD patients were closely related. Results We performed the shotgun genome sequencing of 28 E. coli isolates from ten CD patients and compared genomes from these isolates with already published genomes of CD strains and other pathogenic and non-pathogenic strains. CDEC was shown to belong to A, B1, B2 and D phylogenetic groups. The plasmid and several operons from the reference CD-associated E. coli strain LF82 were demonstrated to be more often present in CDEC genomes belonging to different phylogenetic groups than in genomes of commensal strains. The operons include carbon-source induced invasion GimA island, prophage I, iron uptake operons I and II, capsular assembly pathogenetic island IV and propanediol and galactitol utilization operons. Conclusions Our findings suggest that CDEC are phylogenetically diverse. However, some strains isolated from independent sources possess highly similar chromosome or plasmids. Though no CD-specific genes or functional domains were present in all CD-associated strains, some genes and operons are more often found in the genomes of CDEC than in commensal E. coli. They are principally linked to gut colonization and utilization of propanediol and other sugar alcohols

Do Extracellular Vesicles Derived from Mesenchymal Stem Cells Contain Functional Mitochondria?

Extracellular vesicles (EV) derived from stem cells have become an effective complement to the use in cell therapy of stem cells themselves, which has led to an explosion of research into the mechanisms of vesicle formation and their action. There is evidence demonstrating the presence of mitochondrial components in EV, but a definitive conclusion about whether EV contains fully functional mitochondria has not yet been made. In this study, two EV fractions derived from mesenchymal stromal stem cells (MSC) and separated by their size were examined. Flow cytometry revealed the presence of mitochondrial lipid components capable of interacting with mitochondrial dyes MitoTracker Green and 10-nonylacridine orange; however, the EV response to the probe for mitochondrial membrane potential was negative. Detailed analysis revealed components from all mitochondria compartments, including house-keeping mitochondria proteins and DNA as well as energy-related proteins such as membrane-localized proteins of complexes I, IV, and V, and soluble proteins from the Krebs cycle. When assessing the functional activity of mitochondria, high variability in oxygen consumption was noted, which was only partially attributed to mitochondrial respiratory activity. Our findings demonstrate that the EV contain all parts of mitochondria; however, their independent functionality inside EV has not been confirmed, which may be due either to the absence of necessary cofactors and/or the EV formation process and, probably the methodology of obtaining EV