Competitive reactions method in electrochemistry. A new tool for investigating the anodic intermediates reactivity

Some application features of the competitive reactions method (C.R.M.) for anodically generated agents have been considered. Quantitative characteristics of the (RO)3P, (RO)2 POSiMe3, (EtO)2 PONa, and I2 electrochemically induced intermediates have been presented. It is discussed how to apply the obtained information for stating the nature of respective species. © 1989

Electrochemically induced phosphorylation of alkenes

The processes of electrochemical phosphorylation of alkenes were investigated. It was found that anodically generated radical-cations of trialkyl phosphites, dialkyl trimethylsilyl phosphites, mono-and diamidophosphites were added to olefin molecules to give unsaturated alkenephosphonates. The anodic oxidation of tetraalkyl pyrophosphites proceeds with disintegration of initial radical-cations and leads to mixture alkane-and alkenephosphonates. Greater amounts of alkanephosphonates were formed during anodic oxidation of sodium (or lithium) dialkyl phosphites in the presence of alkenes. © 1997 Published by Elsevier Science Ltd

Non-universal equilibrium crystal shape results from sticky steps

The anisotropic surface free energy, Andreev surface free energy, and equilibrium crystal shape (ECS) z=z(x,y) are calculated numerically using a transfer matrix approach with the density matrix renormalization group (DMRG) method. The adopted surface model is a restricted solid-on-solid (RSOS) model with "sticky" steps, i.e., steps with a point-contact type attraction between them (p-RSOS model). By analyzing the results, we obtain a first-order shape transition on the ECS profile around the (111) facet; and on the curved surface near the (001) facet edge, we obtain shape exponents having values different from those of the universal Gruber-Mullins-Pokrovsky-Talapov (GMPT) class. In order to elucidate the origin of the non-universal shape exponents, we calculate the slope dependence of the mean step height of "step droplets" (bound states of steps) using the Monte Carlo method, where p=(dz/dx, dz/dy)$, and represents the thermal averag |p| dependence of , we derive a |p|-expanded expression for the non-universal surface free energy f_{eff}(p), which contains quadratic terms with respect to |p|. The first-order shape transition and the non-universal shape exponents obtained by the DMRG calculations are reproduced thermodynamically from the non-universal surface free energy f_{eff}(p).Comment: 31 pages, 21 figure

Effect of scanning strategy on mechanical properties of Ti-6Al-4V alloy manufactured by laser direct energy deposition

In this work, we investigated the effect of DED thermal history on the obtained structural and mechanical properties of Ti-6Al-4V using a thermocouple. As a result of the study, the specific DED process parameters allow the same mechanical characteristics for as-built titanium alloy and the alloy after heat treatmen

Применение двухточечного метода калибровки для тепловизионных матриц фирмы ULIS

The objective of this work is research and modification of the two-point calibration method for long wavelength infrared uncooled microbolometer ULIS' matrices. The ultimate goal is to obtain better thermal image for the end-user, where quality criteria are such characteristics as a visual contrast, ability to distinguish fine details, and noisy image as less as possible.In considering the most common calibration algorithm of infrared uncooled microbolometer matrices we used the study results of other authors in which results and comparative analyses of the most effective algorithms were provided. Based on these investigations, to make modification have been chosen quite effective and at the same time simple computationally two-point calibration method, which is sufficient for most tasks entrusted to thermal imager.Modification of the two-point calibration method involves introducing variable reference voltages, which nominal values depend on the temperature range of the matrix. In the original version of the algorithm a reference voltage was selected for the whole range of possible temperatures of the matrix, which did not guarantee the required level of minimum sensitivity. The results of the algorithm embedded in a real device and experimental results proved the effectiveness of this modification.The known specialized literature describing calibration methods for long wavelength infrared uncooled microbolometer matrices do not mention this type of modification.The method described in this publication can be applied to various practical implementations of the thermal imagers without cover and algorithms, which can improve image quality.The article shows advisability and effectiveness of using the modified two-point calibration method for design of thermal imagers without cover with a wide range of operating temperatures.Приводятся краткий обзор наиболее распространённых на текущее время методов калибровки (двухточечная и многоточечная) и вариант модифицированного алгоритма двухточечной калибровки приборов бесшторкового типа, построенных на основе неохлаждаемых микроболометрических матриц фирмы ULIS (Long Wavelength Infrared uncooled microbolometer). В статье отражены описание процедуры калибровки, получения результатов, кратко описан интерфейс программы, реализованной на языке С и используемой в данной работе, а так же сам прибор, используемый для апробации модифицированного алгоритма. Результаты данной работы могут быть интересны при практической реализации бесшторковых тепловизоров и алгоритмов улучшения качества изображения

Observation of Dispersion in the J=2+ Collective Modes of He-3-B by Nonlinear Acoustic Spectroscopy

Parametric excitation yields new results, which cannot be obtained by conventional linear spectroscopy, on the collective modes in superfluid He-3-B. In our ultrasonic experiments, performed in a chamber with four quartz crystals, we have excited the real squashing (J = 2+) modes by two simultaneous sound waves which are mutually either parallel, orthogonal, or antiparallel. Qualitatively these results are in agreement with the theoretical dispersion relation of the J = 2+ modes, and quantitatively we have been able to extract the collective-mode velocities from the line splittings in zero magnetic field

Taxonomic composition and biodiversity of the gut microbiome from patients with irritable bowel syndrome, ulcerative colitis, and asthma

To date, the association of an imbalance of the intestinal microbiota with various human diseases, including both diseases of the gastrointestinal tract and disorders of the immune system, has been shown. However, despite the huge amount of accumulated data, many key questions still remain unanswered. Given limited data on the composition of the gut microbiota in patients with ulcerative colitis (UC) and irritable bowel syndrome (IBS) from different parts of Siberia, as well as the lack of data on the gut microbiota of patients with bronchial asthma (BA), the aim of the study was to assess the biodiversity of the gut microbiota of patients with IBS, UC and BA in comparison with those of healthy volunteers (HV). In this study, a comparative assessment of the biodiversity and taxonomic structure of gut microbiome was conducted based on the sequencing of 16S rRNA genes obtained from fecal samples of patients with IBS, UC, BA and volunteers. Sequences of the Firmicutes and Bacteroidetes types dominated in all samples studied. The third most common in all samples were sequences of the Proteobacteria type, which contains pathogenic and opportunistic bacteria. Sequences of the Actinobacteria type were, on average, the fourth most common. The results showed the presence of dysbiosis in the samples from patients compared to the sample from HVs. The ratio of Firmicutes/Bacteroidetes was lower in the IBS and UC samples than in HV and higher the BA samples. In the samples from patients with intestinal diseases (IBS and UC), an increase in the proportion of sequences of the Bacteroidetes type and a decrease in the proportion of sequences of the Clostridia class, as well as the Ruminococcaceae, but not Erysipelotrichaceae family, were found. The IBS, UC, and BA samples had signif icantly more Proteobacteria sequences, including Methylobacterium, Sphingomonas, Parasutterella, Halomonas, Vibrio, as well as Escherichia spp. and Shigella spp. In the gut microbiota of adults with BA, a decrease in the proportion of Roseburia, Lachnospira, Veillonella sequences was detected, but the share of Faecalibacterium and Lactobacillus sequences was the same as in healthy individuals. A signif icant increase in the proportion of Halomonas and Vibrio sequences in the gut microbiota in patients with BA has been described for the f irst time

In vitro degradation behavior and cytocompatibility of Mg–Zn–Zr alloys

Zinc and zirconium were selected as the alloying elements in biodegradable magnesium alloys, considering their strengthening effect and good biocompatibility. The degradation rate, hydrogen evolution, ion release, surface layer and in vitro cytotoxicity of two Mg–Zn–Zr alloys, i.e. ZK30 and ZK60, and a WE-type alloy (Mg–Y–RE–Zr) were investigated by means of long-term static immersion testing in Hank’s solution, non-static immersion testing in Hank’s solution and cell-material interaction analysis. It was found that, among these three magnesium alloys, ZK30 had the lowest degradation rate and the least hydrogen evolution. A magnesium calcium phosphate layer was formed on the surface of ZK30 sample during non-static immersion and its degradation caused minute changes in the ion concentrations and pH value of Hank’s solution. In addition, the ZK30 alloy showed insignificant cytotoxicity against bone marrow stromal cells as compared with biocompatible hydroxyapatite (HA) and the WE-type alloy. After prolonged incubation for 7 days, a stimulatory effect on cell proliferation was observed. The results of the present study suggested that ZK30 could be a promising material for biodegradable orthopedic implants and worth further investigation to evaluate its in vitro and in vivo degradation behavior

The Phylogenetics and Ecology of the Orthopoxviruses Endemic to North America

The data presented herein support the North American orthopoxviruses (NA OPXV) in a sister relationship to all other currently described Orthopoxvirus (OPXV) species. This phylogenetic analysis reaffirms the identification of the NA OPXV as close relatives of “Old World” (Eurasian and African) OPXV and presents high support for deeper nodes within the Chordopoxvirinae family. The natural reservoir host(s) for many of the described OPXV species remains unknown although a clear virus-host association exists between the genus OPXV and several mammalian taxa. The hypothesized host associations and the deep divergence of the OPXV/NA OPXV clades depicted in this study may reflect the divergence patterns of the mammalian faunas of the Old and New World and reflect a more ancient presence of OPXV on what are now the American continents. Genes from the central region of the poxvirus genome are generally more conserved than genes from either end of the linear genome due to functional constraints imposed on viral replication abilities. The relatively slower evolution of these genes may more accurately reflect the deeper history among the poxvirus group, allowing for robust placement of the NA OPXV within Chordopoxvirinae. Sequence data for nine genes were compiled from three NA OPXV strains plus an additional 50 genomes collected from Genbank. The current, gene sequence based phylogenetic analysis reaffirms the identification of the NA OPXV as the nearest relatives of “Old World” OPXV and presents high support for deeper nodes within the Chordopoxvirinae family. Additionally, the substantial genetic distances that separate the currently described NA OPXV species indicate that it is likely that many more undescribed OPXV/NA OPXV species may be circulating among wild animals in North America