Pushing the limits of energetic materials - the synthesis and characterization of dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate

The safe preparation and characterization (XRD, NMR and vibrational spectroscopy, DSC, mass spectrometry, sensitivities) of a new explosive dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) that outperforms all other commonly used explosive materials is detailed. While much publicized high-performing explosives, such as octanitrocubane and CL-20, have been at the forefront of public awareness, this compound differs in that it is simple and cheap to prepare from commonly available chemicals. TKX-50 expands upon the newly exploited field of tetrazole oxide chemistry to produce a material that not only is easily prepared and exceedingly powerful, but also possesses the required thermal insensitivity, low toxicity, and safety of handling to replace the most commonly used military explosive, RDX (1,3,5-trinitro-1,3,5-triazacyclohexane). In addition, the crystal structures of the intermediates 5,5'-bistetrazole-1,1'-diol dihydrate, 5,5'-bistetrazole-1,1'-diol dimethanolate and dimethylammonium 5,5'-bistetrazole-1,1'-diolate were determined and presented

Structure, bonding and morphology of hydrothermally synthesised xonotlite

The authors have systematically investigated the role of synthesis conditions upon the structure and morphology of xonotlite. Starting with a mechanochemically prepared, semicrystalline phase with Ca/Si=1, the authors have prepared a series of xonotlite samples hydrothermally, at temperatures between 200 and 250 degrees C. Analysis in each case was by X-ray photoelectron spectroscopy, environmental scanning electron microscopy and X-ray diffraction. The authors’ use of a much lower water/solid ratio has indirectly confirmed the ‘through solution’ mechanism of xonotlite formation, where silicate dissolution is a key precursor of xonotlite formation. Concerning the role of temperature, too low a temperature (~200 degrees C) fails to yield xonotlite or leads to increased number of structural defects in the silicate chains of xonotlite and too high a temperature (>250 degrees C) leads to degradation of the xonotlite structure, through leaching of interchain calcium. Synthesis duration meanwhile leads to increased silicate polymerisation due to diminishing of the defects in the silicate chains and more perfect crystal morphologies

Scintillation proportional Xe counter with WLS fiber readout for low-energy X-rays

A gas Xe based scintillation proportional counter with cylindrical geometry and wavelength shifting (WLS) fiber readout for X-rays of energy 0.5 - 100 keV is proposed. With such a design large sizes and sensitive area of the counter with a fairly well uniformity is possible. The counter could be used for "dark matter" search and neutrino magnetic moment measurement and for detection of small amounts or traces of radioactive elements in substances or environment.Comment: LaTeX 4 pages, 3 figures in eps, Submitted to NI

In Referense to the Disruption of Verbal Material Consolidation during Medical Sleep

We discuss the problem of the influence of the intravenous anesthetic “Propofol” on the process of human memory consolidation during surgery. This study is relevant because of two co-existing factors. The first is the wide use of propofol during surgical interventions in order to obtain a sedative effect. The second is presence of controversy data about the amnestic effects of the drug on the consolidation of human memory. So, we need to investigate this topic to ensure the safety of propofol medical usage. We used verbal stimuli — 40 words from the Russian language with non-repeating first three letters. Two types of reproduction indicators were compared between three groups — experimental, control and reference. There was no difference found between subjects who were put to sleep and those who were not put to sleep with an anesthetic during surgery. At the same time, the results of reproduction of the memorized material significantly differ from random ones in both groups.В работе обсуждается проблема влияния внутривенного анестетика «Пропофол» на процесс консолидации памяти человека во время хирургической операции. Актуальность исследования обусловлена широтой применения пропофола во время операционных вмешательств с целью получения седативного эффекта при наличии противоречивых данных о наличии амнезогенного влияния препарата на консолидацию памяти человека. Использовались вербальные стимулы — 40 слов из русского языка с неповторяющимися тремя первыми буквами. Два типа показателей воспроизведения сравнивались между тремя группами — экспериментальной, контрольной и референсной. Показано отсутствие различий между испытуемыми, введенными и не введенными в состояние сна с помощью анестетика во время хирургического вмешательства. При этом результаты воспроизведения запомненного материала значимо отличаются от случайных в обеих группах.Исследование выполнено при поддержке гранта РФФИ № 19-29-07069

Coalescent-based genome analyses resolve the early branches of the euarchontoglires

Despite numerous large-scale phylogenomic studies, certain parts of the mammalian tree are extraordinarily difficult to resolve. We used the coding regions from 19 completely sequenced genomes to study the relationships within the super-clade Euarchontoglires (Primates, Rodentia, Lagomorpha, Dermoptera and Scandentia) because the placement of Scandentia within this clade is controversial. The difficulty in resolving this issue is due to the short time spans between the early divergences of Euarchontoglires, which may cause incongruent gene trees. The conflict in the data can be depicted by network analyses and the contentious relationships are best reconstructed by coalescent-based analyses. This method is expected to be superior to analyses of concatenated data in reconstructing a species tree from numerous gene trees. The total concatenated dataset used to study the relationships in this group comprises 5,875 protein-coding genes (9,799,170 nucleotides) from all orders except Dermoptera (flying lemurs). Reconstruction of the species tree from 1,006 gene trees using coalescent models placed Scandentia as sister group to the primates, which is in agreement with maximum likelihood analyses of concatenated nucleotide sequence data. Additionally, both analytical approaches favoured the Tarsier to be sister taxon to Anthropoidea, thus belonging to the Haplorrhine clade. When divergence times are short such as in radiations over periods of a few million years, even genome scale analyses struggle to resolve phylogenetic relationships. On these short branches processes such as incomplete lineage sorting and possibly hybridization occur and make it preferable to base phylogenomic analyses on coalescent methods

Mesozoic retroposons reveal parrots as the closest living relatives of passerine birds

The relationships of passerines (such as the well-studied zebra finch) with non-passerine birds is one of the great enigmas of avian phylogenetic research, because decades of extensive morphological and molecular studies yielded highly inconsistent results between and within data sets. Here we show the first application of the virtually homoplasy-free retroposon insertions to this controversy. Our study examined ~200,000 retroposon-containing loci from various avian genomes and retrieved 51 markers resolving early bird phylogeny. Among these, we obtained statistically significant evidence that parrots are the closest and falcons the second-closest relatives of passerines, together constituting the Psittacopasserae and the Eufalconimorphae, respectively. Our new and robust phylogenetic framework has substantial implications for the interpretation of various conclusions drawn from passerines as model organisms. This includes insights of relevance to human neuroscience, as vocal learning (that is, birdsong) probably evolved in the psittacopasseran ancestor, >30 million years earlier than previously assumed