Chemical Oxidative Condensation of Benzidine in Non-Aqueous Medium: Synthesis and Investigation of Oligomers and Polymer with Benzidine Diimine Units

The oxidative condensation of benzidine has been carried out in acetic acid media using potassium peroxydisulfate as the oxidizing agent. Using different monomer–oxidant molar ratios, benzidine dimer, trimer, and polymer have been synthesized for the first time. It was established that the polybenzidine structure is composed from a sequence of benzidinediimine and diphenylene units with amino/amino end groups and thus proves the possibility of ammonia elimination during the oxidative polymerization of aromatic diamines. The method seems to be common for the synthesis of polymers with the sequence of aromatic diimine and arylene units. TGA analysis of the obtained trimer and polymer was investigated, and the high thermostability of both the polymer and trimer was revealed. According to the obtained data, both polymer and trimer matrix decomposition started at 300 °C, and at 600 °C, 75.94% and of 69.40% of the initial weight remained, correspondingly. Conductivities of the polymer and trimer show a semiconductor-type change from temperature and after doping show an increase in conductivity up to 10−4 Sm/cm.

The genomic loci of specific human tRNA genes exhibit ageing-related DNA hypermethylation

The epigenome has been shown to deteriorate with age, potentially impacting on ageing-related disease. tRNA, while arising from only ˜46 kb (<0.002% genome), is the second most abundant cellular transcript. tRNAs also control metabolic processes known to affect ageing, through core translational and additional regulatory roles. Here, we interrogate the DNA methylation state of the genomic loci of human tRNA. We identify a genomic enrichment for age-related DNA hypermethylation at tRNA loci. Analysis in 4,350 MeDIP-seq peripheral-blood DNA methylomes (16–82 years), identifies 44 and 21 hypermethylating specific tRNAs at study-and genome-wide significance, respectively, contrasting with none hypomethylating. Validation and replication (450k array and independent targeted Bisuphite-sequencing) supported the hypermethylation of this functional unit. Tissue-specificity is a significant driver, although the strongest consistent signals, also independent of major cell-type change, occur in tRNA-iMet-CAT-1-4 and tRNA-Ser-AGA-2-6. This study presents a comprehensive evaluation of the genomic DNA methylation state of human tRNA genes and reveals a discreet hypermethylation with advancing age.

On a boundary value problem for a mixed equation with three planes of type change in an infinite prismatic domain

В данной работе в бесконечной призматической области формулируется и изучается одна задача для параболо-гиперболического уравнения c тремя плоскостями изменения типа. Основным методам исследования поставленной задачи является преобразование Фурье. Доказана единственность и существование решения поставленной задачи In this paper, in an infinite prismatic domain, one problem is formulated and studied for a parabolic-hyperbolic equation with three planes of type change. The main methods for studying the problem posed is the Fourier transform. The uniqueness and existence of a solution to the problem is proved.

A compact core-jet structure in the changing-look Seyfert NGC 2617

ABSTRACT The nearby face-on spiral galaxy NGC 2617 underwent an unambiguous ‘inside–out’ multiwavelength outburst in Spring 2013, and a dramatic Seyfert-type change probably between 2010 and 2012, with the emergence of broad optical emission lines. To search for the jet activity associated with this variable accretion activity, we carried out multiresolution and multiwavelength radio observations. Using the very long baseline interferometric (VLBI) observations with the European VLBI Network at 1.7 and 5.0 GHz, we find that NGC 2617 shows a partially synchrotron self-absorbed compact radio core with a significant core shift, and an optically thin steep-spectrum jet extending towards the north up to about 2 pc in projection. We also observed NGC 2617 with the electronic Multi-Element Remotely Linked Interferometer Network at 1.5 and 5.5 GHz, and revisited the archival data of the Very Large Array (VLA) and the Very Long Baseline Array (VLBA). The radio core had a stable flux density of ∼1.4 mJy at 5.0 GHz between 2013 June and 2014 January, in agreement with the expectation of a supermassive black hole in the low accretion rate state. The northern jet component is unlikely to be associated with the ‘inside–out’ outburst of 2013. Moreover, we report that most optically selected changing-look active galactic nuclei (AGN) at z &lt; 0.83 are sub-mJy radio sources in the existing VLA surveys at 1.4 GHz, and it is unlikely that they are more active than normal AGN at radio frequencies.

ANALISIS PRODUKTIVITAS DAN DAMPAK LINGKUNGAN AKIBAT STRATEGI PERUBAHAN JENIS BAHAN PELEDAK DI PT SEMEN BATURAJA (PERSERO) TBK

On limestone blasting activities besides safety there are two other important factors that must be highly considered, that are productivity and environmental impacts that caused, along with the replacement of the blasting contractor at PT Semen Baturaja (Persero) Tbk and accompanied by the strategy of explosive type change that used from ANFO with electric detonator to DABEX with non electric detonator. So, it is necessary an analysis of productivity and environmental impacts that caused, whether for the better or vice versa. The research method that used is qualitative triangulation research using data from direct observation in field, managing documentation data and conducting deep interview with parties who are directly or indirectly involved on limestone blasting activities. Interview was conducted with 10 samples representing representatives of Mining Division work unit with representatives from Echelon 1, Echelon III, Echelon IV and daily workers. From the testing data obtained that the strategy of explosive type change from productivity side is better and more efficient whereas from environmental impacts caused side is not better especially with the use of DABEX which cause an increased level of vibration. Based on these results, it is necessary to make improvements to the blasting method or to find for other alternative explosives that can increase productivity but have minimal environmental impact.

Home is where the heart is: the analysis of Chinese cultural identity of international students in China ——Based on the questionnaire of 800 international students in Guangdong universities

In recent years, with the number of international students in China has increased further, how to enhance the Chinese cultural identity of international students is the key issue in the development of study in China. Based on the international students in universities of Guangdong province as an example, through questionnaire survey and data analysis, we found that scholarship and family background are the important factors that can influence the level of Chinese cultural identity of international students. The level of Chinese cultural identity of male international students is higher than that of female international students, and there is no significant difference in the level of Chinese cultural identity of international students with different degrees. In addition, we focus on international students who from "the Belt and Road" countries and find that this group has a higher level of Chinese cultural identity and presents a "W" type change with the increase of time in China. In order to further improve the quality of international students studying in China, universities should profoundly grasp the "W" type change in the identification level of international students, adopt the mode of differentiated management at different time stages and combine "the Belt and Road" development strategy to promote the connotative development of international students studying in China.