Ni-Based Catalysts for the Hydrotreatment of Fast Pyrolysis Oil

Catalytic hydrotreatment is an attractive technology to convert fast pyrolysis oil to stabilized oil products for co processing in conventional crude oil refinery units. We report here the use of novel bimetallic NiCu- and NiPd-based (Picula) catalysts characterized by a high Ni content (29-58 wt %) and prepared using a sol gel method with SiO2, La2O3, kaolin, ZrO2, and combinations thereof as the support, for the catalytic hydrotreatment of fast pyrolysis oil. The experiments were performed in a batch autoclave (1 h at 150 degrees C, 3 h at 350 degrees C, and 200 bar initial pressure at 350 degrees C). The catalyst with the highest nickel loading (58 wt % Ni) promoted with Pd (0.7 wt %) was the most active, yielding oil products with improved properties compared to the crude pyrolysis oil (lower oxygen content, higher solubility in hydrocarbons, and less tendency for coke formation). For all Picula catalysts, except the ZrO2-based catalysts, methane formation was considerably lower than for Ru/C, the benchmark catalyst in catalytic hydrotreatment of fast pyrolysis oil. To anticipate possible catalyst deactivation at very long times on stream, catalyst regeneration studies were performed using thermogravimetric analysis. Analyses of the regenerated catalysts (X-ray diffraction, high-resolution transmission electron microscopy, and Brunauer Emmett Teller surface area) showed the occurrence of active metal agglomeration.</p

Uakitite, VN, a new mononitride mineral from uakit iron meteorite (IIAB)

Uakitite was observed in small troilite–daubréelite (±schreibersite) inclusions (up to 100 µm) and in large troilite–daubréelite nodules (up to 1 cm) in Fe-Ni-metal (kamacite) of the Uakit iron meteorite (IIAB), Republic of Buryatia, Russia. Such associations in the Uakit meteorite seemed to form due to high-temperature (&gt;1000 °C) separation of Fe-Cr-rich sulfide liquid from Fe-metal melt. Most inclusions represent alternation of layers of troilite and daubréelite, which may be a result of solid decay of an initial Fe-Cr-sulfide. These inclusions are partially resorbed and mainly located in fissures of the meteorite, which is now filled with magnetite, and rarely other secondary minerals. Phase relations indicate that uakitite is one of the early minerals in these associations. It forms isometric (cubic) crystals (in daubréelite) or rounded grains (in schreibersite). The size of uakitite grains is usually less than 5 µm. It is associated with sulfides (daubréelite, troilite, grokhovskyite), schreibersite and magnetite. Carlsbergite CrN, a more abundant nitride in the Uakit meteorite, was not found in any assemblages with uakitite. Physical and optical properties of uakitite are quite similar to synthetic VN: yellow and transparent phase with metallic luster; Mohs hardness: 9–10; light gray color with a pinky tint in reflected light; density (calc.) = 6.128 g/cm3. Uakitite is structurally related to the osbornite group minerals: carlsbergite CrN and osbornite TiN. Structural data were obtained for three uakitite crystals using the electron backscatter diffraction (EBSD) technique. Fitting of the EBSD patterns for a synthetic VN model (cubic, Fm-3m, a = 4.1328(3) Å; V = 70.588(9) Å3; Z = 4) resulted in the parameter MAD = 0.14–0.37° (best-good fit). Analytical data for uakitite (n = 54, in wt. %) are: V, 71.33; Cr, 5.58; Fe, 1.56; N, 21.41; Ti, below detection limit (&lt;0.005). The empirical formula (V0.91Cr0.07Fe0.02)1.00N1.00 indicates that chromium incorporates in the structure according to the scheme V3+ → Cr3+ (up to 7 mol. % of the carlsbergite end-member). © 2020 by the authors. Licensee MDPI, Basel, Switzerland.Russian Foundation for Basic Research, RFBR: 17-05-00129, IGM SD 0330-2016-0005Government Council on Grants, Russian FederationMinistry of Science and Higher Education of the Russian FederationFunding: The investigations were partly supported by RFBR (grant 17-05-00129) and the State assignment project (IGM SD 0330-2016-0005). This work was also supported by the Initiative Project of Ministry of Science and Higher Education of the Russian Federation and by Act 211 of the Government of the Russian Federation, agreement no. 02.A03.21.0006

Dipolar resonances in conductive carbon micro-fibers probed by near-field terahertz spectroscopy

We observe dipole resonances in thin conductive carbon micro-fibers by detecting an enhanced electric field in the near-field of a single fiber at terahertz (THz) frequencies. Time-domain analysis of the electric field shows that each fiber sustains resonant current oscillations at the frequency defined by the fiber's length. Strong dependence of the observed resonance frequency and degree of field enhancement on the fibers' conductive properties enable direct non-contact probing of the THz conductivity in single carbon micro-fibers. We find the conductivity of the fibers to be within the range of 1– 5×104 S/m. This approach is suitable for experimental characterization of individual doped semiconductor resonators for THz metamaterials and devices

Analysis of tuberculosis sick rate in Siberian federal district

The paper presents the materials of the complex epidemiological evaluation of tuberculosis process by its main indicators (incident cases, prevalence and mortality) in the Siberian Federal district over the period of 2002-2014. The ranking of the territories included in the Siberian Federal district was performed by the integral index. That allowed to identify three groups of territories by the level of intensity of TB epidemiological process (favorable, typical, unfavorable). The most favorable epidemiological situation was registered in Tomsk region, the most unfavorable one - in the Republic of Tuva

THE DETECTION OF EPIDEMIC SUBTYPES OF BEIJING GENOTYPE OF MYCOBACTERIUM TUBERCULOSIS CIRCULATED IN THE PRIMORSKY KRAI

Background. The Far East is the territory with high rate of incidence and prevalence of tuberculosis. Cases of tuberculosis caused by epidemic strains have high frequency of MDR and XDR. It is important to study the prevalence of TB in areas with a high burden of infection, to which the Far East belongs. The aim of the research is to carry out genotyping of strains and assess the prevalence of CC1 and CC2 subtypes in the territory of Primorsky Krai. Materials and methods. The DNAs of 99 clinical isolates of MBT from Primorsky Krai have been genotyped by the 24-locus MIRU-VNTR and RD105/RD207. Results. The dominant number of strains pertained to Beijing genotype (59.6 %). The express method revealed 22 isolates of the CC2/W148 subtype, which had 6 different MIRU-VNTR-24 profile. According to MLVA classification MtbC 15-9, the most common among the isolates of CC2/W148 profile is 100-32 (59.1 %). Among these profiles the highest frequency of MDR/XDR was recorded – 69,2 %. According to the results of the express analysis, 39 isolates with 26 different MIRU-VNTR-24 profiles belonged to the CC1 subtype, of which the dominant number belonged to 99-32 and 94-32. Conclusions. The methods of express genotyping of epidemic subtypes of the Beijing genotype are very important for epidemiological surveillance and clinical practice. The developed methods allow to define a wider range of strains than previously used methods

Molecular epidemiology of multidrug resistant tuberculosis in Mongolia and Eastern Siberia: two independent dissemination processes for dominant strains

Mongolia and Russia are among the countries with the high tuberculosis (TB) burden. The prevalence of tuberculosis, including multidrug-resistant tuberculosis (MDR), in Eastern Siberia bordering Mongolia is significantly higher than in the European part of Russia. In addition, unlike Mongolia, Eastern Siberia is characterized by a high prevalence of HIV infection. The cross-border spread of socially significant infections in these countries seems to occur due to their wide-range cooperation and cultural exchange. Whereas the HIV infection has no epidemiological significance for Mongolia at the moment, tuberculosis, however, has a similar prevalence on both sides of the border. The aim was to evaluate the cross-border MDR M. tuberculosis distribution in Mongolia and Eastern Siberia by using molecular genetic data. Materials and methods. A total of 1045 M. tuberculosis strains isolated in Mongolia (291) and the three regions of Eastern Siberia (754) were studied by using the MIRU-VNTR-24 loci genotyping. The CC2/W148 and CC1 subtypes were identified by the specific deletion in the kdpD gene and SNP in the pks17 gene at position 1887060, respectively. Phylogenetic analysis of MIRU-VNTR patterns was carried out by generating UPGMA tree and maximum likelihood tree. Results. The Beijing genotype was found in 75.3% (219/291) and 69.0% (520/754) from Mongolian and East Siberian collection, respectively. Common minor genotypes were LAM (11.0% and 15.1%), T (10.3% and 4.5%), and Haarlem (1.4% and 2.4%) found in Mongolia and Eastern Siberia, respectively. The genotypes S (1.3%) and Ural (5.0%) were found solely in the Russia-derived samples. The main epidemic Beijing subtypes in each country belonged to different clonal complexes (CC): the majority of Mongolian Beijing strains displayed profiles 342-32, 3819-32, 1773-32 MLVA types and belonged to the CC4 subtype; Russian Beijing strains mainly belonged to the CC1 (43.7% — 227/520) and CC2/W148 (34.8% — 181/520) subtypes. The MDR level and distribution patterns differed significantly between Mongolia and Eastern Siberia. Modeling of Beijing strain expansion evidences about extremely subtle contribution of the M. tuberculosis cross-border transmission between Mongolia and Russia. The phylogenetic reconstruction of Beijing CC4 subtype evolution in Mongolia suggests that its distribution is primarily associated with China and other countries of the Western Pacific Region. Three main phylogenetic branches of CC4 subtype were traced, which probably spread throughout Mongolia in the 11—12th centuries. It may be assumed that spreading of the epidemic Beijing CC4 subtype might occur in two stages: early period — emergence of ancestral CC4 variants in Mongolia or their introduction from China (they are homologous to the strains preserved in the Chinese population), later period — dissemination due to the active exchange of M. tuberculosis with countries of Southeast Asia, but not Russia. Conclusion. Using MIRU-VNTR-24 genotyping as well as classification according to specific single nucleotide polymorphisms specific to certain Beijing subtypes, it allowed to describe separate patterns of the epidemic variants spread in Mongolia and Russia. It has been demonstrated that emergence and spread of MDR-TB in Mongolia are entirely iatrogenic in nature, while the epidemic subtypes of the Beijing genotype (subtypes CC1 and CC2/W148) contribute markedly into the MDR-TB spreading in Eastern Siberia

Изменение площади и объёма ледников Горного Алтая (Россия) с середины ХХ в. по данным космических съёмок

The paper examines changes in the area and volume of the Katun river basin glaciers, North and South Chu glaciers of the Altai Mountains since the beginning of the USSR glaciers inventarization to the present. For this purpose, we used USSR Glaciers Inventory data, space imagery – CORONA-1968, ALOS PRISM-2008, Landsat and ASTER 2000–2012. In total, glaciers have lost 172.4 km2 (27.4%) of its area.Рассматривается изменение площади и объёма ледников Горного Алтая с начала каталогизации ледников СССР по настоящее время. Для оценки изменений площади ледников использованы данные Каталога ледников СССР и космические снимки со спутников CORONA, ALOS PRISM, Landsat и ASTER.К 2008 г. ледники Катунского, Северо- и Южно-Чуйского хребтов потеряли 172,4 км2 площади, или 27,7%. Суммарное сокращение объёма ледников составило 8,9 км3. Объёмы ледников вычислены с помощью корреляционных зависимостей, полученных по данным полевого радиолокационного зондирования алтайских ледников. Сравнение космических снимков 2004 и 2012 гг. с данными середины прошлого века позволило сделать вывод об увеличении скорости сокращения площади ледников в последнее десятилетие в 1,5–2 раза

Duration of the Process of Complete Synchronizationof Two Coupled Identical Chaotic Systems

We consider the time required for complete synchronization of two identical one-way coupled vander Pol-Duffing oscillators occurring in the regime of dynamic chaos. The influence of the initial phase differ-ence between oscillators on the duration of the process of complete synchronization has been studied. At a fixedphase of chaotic oscillations of the self-excited drive oscillator, the period of time (past the coupling onset) during which the complete synchronization regime is established depends on the phase of the self-excited responseoscillatorComment: 4 pages, 2 figure

Application of PCR-based approaches for evaluation of cell-free DNA fragmentation in colorectal cancer

Cell-free DNA (cfDNA) testing is the core of most liquid biopsy assays. In particular, cfDNA fragmentation features could facilitate non-invasive cancer detection due to their interconnection with tumor-specific epigenetic alterations. However, the final cfDNA fragmentation profile in a purified sample is the result of a complex interplay between informative biological and artificial technical factors. In this work, we use ddPCR to study cfDNA lengths in colorectal cancer patients and observe shorter and more variable cfDNA fragments in accessible chromatin loci compared to the densely packed pericentromeric region. We also report a convenient qPCR system suitable for screening cfDNA samples for artificial high molecular weight DNA contamination

Viral Load in COVID-19: Underestimated Clinical and Epidemiological Marker

Background. The viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the new coronavirus infection, is becoming increasingly important in clinical and epidemiological contexts. Despite this, there are significant complexities in the implementation of viral load quantitative measurement into clinical practice due to the limited approaches to its assessment.The aim of this work was to develop an approach for SARS-CoV-2 viral load analysis by the value of sample threshold cycles (Ct) relative to the Ct of the internal control sample obtained in routine PCR diagnostics of the COVID-19, and to use this approach for quantitative monitoring of viral load in patients with first positive SARS-CoV-2 test from the Irkutsk region.Materials and methods. Using regression models based on the least squares method, an approach to determine the number of copies of SARS-CoV-2 RNA in 1 ml of nasopharyngeal secretion was developed. The viral load of SARS-CoV-2 was assessed in nasopharyngeal and pharyngeal samples obtained from 1370 patients from Irkutsk and Angarsk with primary diagnosed positive PCR result in the period from July 1 to November 10, 2020.Results. A tenfold increase in the average monthly viral load among patients in September-October 2020 was revealed. We assume that the change in the epidemiological pattern of the spread of the new coronavirus infection during this period is associated with an increase in the number of contacts in the population due to the school year beginning. Higher viral loads are observed in populations at risk for COVID-19 – among healthcare workers and adults/elderly patients. Conclusion. The development of a standardized quantification of SARS-CoV-2 viral load in the nasopharyngeal samples can be a predictive clinical marker and a reliable tool for improving COVID-19 surveillance using the proposed approach to assess average viral load in a local population