Improvement of the pyrolysis process

In modern chemistry pyrolysis is the principal process and large-tonnage provider, primarily, of lower olefins - ethylene, propylene - as well as butadiene, benzene and other products. The level of efficiency of the pyrolysis process largely determines the development of the petrochemical industry in whole, therefore rationalization of the process is an ongoing task of high relevance. The aim of this work is to develop a method for increasing the efficiency of the pyrolysis for lower olefins on the base of the analysis of the mechanism of the process with the possibility of controlling it. The kinetics of the interaction of the hydrocarbons with hydrogen atoms, methyl radicals and their mixtures were determined. The data on the relative reactivity of bonds of different types in reactions with hydrogen atoms and methyl radicals and the data on the effective relative reactivity when using an inert diluent increase our knowledge of the pyrolysis of feedstock of any given composition. A method based on the influence of hydrogen on the thermal reactions of alkanes and alkenes was developed to increase the selectivity of the process for the target product (lower olefins) and to reduce the yield of the liquid products of condensation and specific energy consumption. © 2018 WIT Press.ACKNOWLEDGEMENTS This research was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006

Acceleration of boiling in the desired conditions: Application of its effect in the refinery and petrochemical industries

Rectification is used in almost all the processes of refinery and petrochemical industries. In most cases light fractions or individual components in the bottom of rectification towers are significantly higher than the thermodynamic equilibrium. The reason for this is that in the specified heat supply to the distillation residue of the fractionating tower and its specific volume, the boil-up rate of the light fractions or of some hydrocarbons is lower than the required value. The authors prove that the injection of the surface active agent in a feed stream of the fractionating tower in optimal concentration aimed at the potential content of the bottom product doubles the boiling rate of the residual light fractions in the distillation residue of the fractionating tower. It reduces the residual content of the light components in the bottom of rectification towers and improves quality of the previous fraction. The described effect has an industrial approbation. The result can be used in the running of fractionating towers for various purposes. © 2014 WIT Press.International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

Gain of DNA methylation is enhanced in the absence of CTCF at the human retinoblastoma gene promoter

<p>Abstract</p> <p>Background</p> <p>Long-term gene silencing throughout cell division is generally achieved by DNA methylation and other epigenetic processes. Aberrant DNA methylation is now widely recognized to be associated with cancer and other human diseases. Here we addressed the contribution of the multifunctional nuclear factor CTCF to the epigenetic regulation of the human <it>retinoblastoma </it>(<it>Rb</it>) gene promoter in different tumoral cell lines.</p> <p>Methods</p> <p>To assess the DNA methylation status of the <it>Rb </it>promoter, genomic DNA from stably transfected human erythroleukemic K562 cells expressing a <it>GFP </it>reporter transgene was transformed with sodium bisulfite, and then PCR-amplified with modified primers and sequenced. Single- and multi-copy integrants with the CTCF binding site mutated were isolated and characterized by Southern blotting. Silenced transgenes were reactivated using 5-aza-2'-deoxycytidine and Trichostatin-A, and their expression was monitored by fluorescent cytometry. <it>Rb </it>gene expression and protein abundance were assessed by RT-PCR and Western blotting in three different glioma cell lines, and DNA methylation of the promoter region was determined by sodium bisulfite sequencing, together with CTCF dissociation and methyl-CpG-binding protein incorporation by chromatin immunoprecipitation assays.</p> <p>Results</p> <p>We found that the inability of CTCF to bind to the <it>Rb </it>promoter causes a dramatic loss of gene expression and a progressive gain of DNA methylation.</p> <p>Conclusions</p> <p>This study indicates that CTCF plays an important role in maintaining the <it>Rb </it>promoter in an optimal chromatin configuration. The absence of CTCF induces a rapid epigenetic silencing through a progressive gain of DNA methylation. Consequently, CTCF can now be seen as one of the epigenetic components that allows the proper configuration of tumor suppressor gene promoters. Its aberrant dissociation can then predispose key genes in cancer cells to acquire DNA methylation and epigenetic silencing.</p

5C analysis of the Epidermal Differentiation Complex locus reveals distinct chromatin interaction networks between gene-rich and gene-poor TADs in skin epithelial cells

YesMammalian genomes contain several dozens of large (>0.5 Mbp) lineage-specific gene loci harbouring functionally related genes. However, spatial chromatin folding, organization of the enhancer-promoter networks and their relevance to Topologically Associating Domains (TADs) in these loci remain poorly understood. TADs are principle units of the genome folding and represents the DNA regions within which DNA interacts more frequently and less frequently across the TAD boundary. Here, we used Chromatin Conformation Capture Carbon Copy (5C) technology to characterize spatial chromatin interaction network in the 3.1 Mb Epidermal Differentiation Complex (EDC) locus harbouring 61 functionally related genes that show lineage-specific activation during terminal keratinocyte differentiation in the epidermis. 5C data validated by 3D-FISH demonstrate that the EDC locus is organized into several TADs showing distinct lineage-specific chromatin interaction networks based on their transcription activity and the gene-rich or gene-poor status. Correlation of the 5C results with genome-wide studies for enhancer-specific histone modifications (H3K4me1 and H3K27ac) revealed that the majority of spatial chromatin interactions that involves the gene-rich TADs at the EDC locus in keratinocytes include both intra- and inter-TAD interaction networks, connecting gene promoters and enhancers. Compared to thymocytes in which the EDC locus is mostly transcriptionally inactive, these interactions were found to be keratinocyte-specific. In keratinocytes, the promoter-enhancer anchoring regions in the gene-rich transcriptionally active TADs are enriched for the binding of chromatin architectural proteins CTCF, Rad21 and chromatin remodeler Brg1. In contrast to gene-rich TADs, gene-poor TADs show preferential spatial contacts with each other, do not contain active enhancers and show decreased binding of CTCF, Rad21 and Brg1 in keratinocytes. Thus, spatial interactions between gene promoters and enhancers at the multi-TAD EDC locus in skin epithelial cells are cell type-specific and involve extensive contacts within TADs as well as between different gene-rich TADs, forming the framework for lineage-specific transcription.This study was supported by the grants 5R01AR064580 and 1RO1AR071727 to VAB, TKS and AAS, as well as by the grants from MRC (MR/ M010015/1) and BBSRC (BB/K010050/1) to VAB