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The results of interdisciplinary research conducted at the Late Neolithic settlements Algai and Oroshaemoe (Aleksandrovo-Gaisky district of Saratov oblast, Lower Volga region) dated back to the ...7th–5th millennia BC are considered. Modern soils of the study area are represented by light chestnut soils (Eutric Cambisols (Loamic, Protocalcic, Ochric)). In archaeological excavations, anthropogenically transformed variants of the same soils have been identified. Reconstruction of paleoenvironmental conditions in the area of archaeological settlements and their comparison with data from other parts of the Lower Volga region attests to periodic aridization and humidization of the climate and the related alternation of the stages of soil formation and sedimentation. An analysis of two neighboring sites indicates that the rate of soil formation in the study area varied from 0.8 to 35 cm/100 years. The soil strata have been identified and subdivided into several series of Holocene soils of different ages. Sterile (light-colored horizons without artifacts) or B horizons serve as parent materials for each of the formed soils. Sterile horizons were formed under arid climatic conditions with the development of salt-affected soils. The duration of the formation of each Holocene soil varied. Cyclic stages of aridization and humidization of the climate have been observed during the entire Holocene against the general background trend of increasing humidization.
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The results of pedogenetic studies conducted on soddy-podzolic soils in Gryazovets district of Vologda oblast are presented. The modern soils of the study area are represented by soddy-podzolic ...soils (Albic Retisols) developed from loamy parent rocks with paleocryogenic features. The role of paleocryolithogenesis in the formation and evolution of modern soddy-podzolic soils in the northeast of the East European Plain is discussed. The considered set of paleocryolithopedogenic processes and paleofeatures in modern zonal soddy-podzolic soils allows us to reconstruct the conditions of soil formation in the periglacial area of the Valdai glaciation. The results obtained have expanded the understanding of the influence of the Late Pleistocene cryogenesis and lithogenesis on the evolution of modern soddy-podzolic soils. It is discussed that paleocryolithogenic soil combinations resulting from the Late Pleistocene and Holocene cryolithogenesis and pedogenesis can be distinguished in the soil cover patterns in the northern part of the East European Plain.
The recent epidemic history of hepatitis B virus (HBV) infections in the United States is complex, as indicated by current disparity in HBV genotype distribution between acute and chronic hepatitis B ...cases and the rapid decline in hepatitis B incidence since the 1990s. We report temporal changes in the genetic composition of the HBV population using whole-genome sequences (n = 179) from acute hepatitis B cases (n = 1,206) identified through the Sentinel County Surveillance for Acute Hepatitis (1998 to 2006). HBV belonged mainly to subtypes A2 (75%) and D3 (18%), with times of their most recent common ancestors being 1979 and 1987, respectively. A2 underwent rapid population expansions in ca. 1995 and ca. 2002, coinciding with transient rises in acute hepatitis B notification rates among adults; D3 underwent expansion in ca. 1998. A2 strains from cases identified after 2002, compared to those before 2002, tended to cluster phylogenetically, indicating selective expansion of specific strains, and were significantly reduced in genetic diversity (P = 0.001) and frequency of drug resistance mutations (P = 0.001). The expansion of genetically close HBV A2 strains was associated with risk of infection among male homosexuals (P = 0.03). Incident HBV strains circulating in the United States were recent in origin and restricted in genetic diversity. Disparate transmission dynamics among phylogenetic lineages affected the genetic composition of HBV populations and their capacity to maintain drug resistance mutations. The tendency of selectively expanding HBV strains to be transmitted among male homosexuals highlights the need to improve hepatitis B vaccination coverage among at-risk adults.
Hepatitis B virus (HBV) remains an important cause of acute and chronic liver disease globally and in the United States. Genetic analysis of HBV whole genomes from cases of acute hepatitis B identified from 1998 to 2006 in the United States showed dominance of genotype A2 (75%), followed by D3 (18%). Strains of both subtypes were recent in origin and underwent rapid population expansions from 1995 to 2000, indicating increase in transmission rate for certain HBV strains during a period of decline in the reported incidence of acute hepatitis B in the United States. HBV A2 strains from a particular cluster that experienced the most recent population expansion were more commonly detected among men who have sex with men. Vaccination needs to be stepped up to protect persons who remain at risk of HBV infection.
The results of microfaunistic (benthic foraminifers) and magnetostratigraphic (paleomagnetic and petromagnetic) studies obtained in the lower part of the Upper Cretaceous deposits of the Kommunar ...section are presented. On the basis of the study of benthic foraminifers, the section consists of middle and upper Turonian, Coniacian, lower and upper Santonian, and basal horizon of the lower Campanian. In addition, all Coniacian zones and subzones of the East European Platform have been established. These data confirm the importance of the Kommunar section as a stratotype of the Volsk Formation (Coniacian of the Middle and Lower Volga region). In the Kommunar section, the Turonian and Coniacian are characterized by a normal polarity, and the Santonian and lower Campanian are characterized by a reversed polarity.
Gas fuel combustion and related problems Bashkatov, VA; Khudyakov, SA; Ignatenko, AV
Journal of physics. Conference series,
10/2021, Volume:
2061, Issue:
1
Journal Article
Peer reviewed
Open access
Abstract
Combustion, as it is well known, is based on chemical reactions. If we look at a clear scientific definition of the term “combustion”, then combustion will be a process of rapid ...high-temperature oxidation, combining physical and chemical phenomena. Combustion consists of a large number of elementary redox processes leading to the redistribution of valence electrons between atoms of interacting substances.Modern theories of combustion relate flame spreading in gases to chemical chain reactions1. Nowadays, in a view of the wide spread of gas, understanding of a ship fuel and analysis of gas related problems of combustion are more and more critical. Gas itself is not able to ignite in a combustion chamber as a conventional fuel just because of compression and temperature rising. It requires a strong and efficient source of fire. The article is focused on analyzing igniting, flame spreading and detonation in a combustion chamber. The detonation condition was assessed in case of using gas as ships fuel.
Hepatitis C is a major public health problem in the United States and worldwide. Outbreaks of hepatitis C virus (HCV) infections are associated with unsafe injection practices, drug diversion, and ...other exposures to blood and are difficult to detect and investigate. Here, we developed and validated a simple approach for molecular detection of HCV transmissions in outbreak settings. We obtained sequences from the HCV hypervariable region 1 (HVR1), using end-point limiting-dilution (EPLD) technique, from 127 cases involved in 32 epidemiologically defined HCV outbreaks and 193 individuals with unrelated HCV strains. We compared several types of genetic distances and calculated a threshold, using minimal Hamming distances, that identifies transmission clusters in all tested outbreaks with 100% accuracy. The approach was also validated on sequences obtained using next-generation sequencing from HCV strains recovered from 239 individuals, and findings showed the same accuracy as that for EPLD. On average, the nucleotide diversity of the intrahost population was 6.2 times greater in the source case than in any incident case, allowing the correct detection of transmission direction in 8 outbreaks for which source cases were known. A simple and accurate distance-based approach developed here for detecting HCV transmissions streamlines molecular investigation of outbreaks, thus improving the public health capacity for rapid and effective control of hepatitis C.
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Composites have been prepared via thermal decomposition of gel-like mixtures containing yttrium, aluminum, and europium(III) salts and ethyl acetate as a basic component. Luminescence of the ...composites is due to Eu
3+
5
D
0,1
→
7
F
j
electronic transitions. The luminescence is excited in intrinsic absorption bands of the Eu
3+
ions and as a result of resonance vibrational energy transfer from the host to their excited state levels and transitions of O
2–
2
p
electrons to the europium 4
f
orbital. The luminescence and luminescence excitation spectra demonstrate changes in the peak position of individual bands, redistribution of their intensity, and changes in their Stark structure. The observed changes are related to the different fractions of fluorine atoms in the composition of activator centers, their concentration, and the Y
3+
: Al
3+
atomic ratio in the synthesis products, obtained at a temperature of 800°C and synthesis times from 4 to 12 h and differing in phase composition and structure.
Prostate cancer is the second most common type of cancer among men. Its main method of treatment is chemotherapy, which has a wide range of side effects. One of the solutions to this challenge is ...targeted delivery to prostate cancer cells. Here we synthesized a novel small-molecule PSMA-targeted conjugate based on the monomethyl auristatin E. Its structure and conformational properties were investigated by NMR spectroscopy. Cytotoxicity, intracellular reactive oxygen species induction, and stability under liver microsomes and P450-cytochrome species were investigated for this conjugate. The conjugate demonstrated 77–85% tumor growth inhibition levels on 22Rv1 (PSMA (+)) xenografts, compared with a 37% inhibition level on PC-3 (PSMA (−)) xenografts, in a single dose of 0.3 mg/kg and a sufficiently high therapeutic index of 21. Acute, chronic, and subchronic toxicities and pharmacokinetics have shown that the synthesized conjugate is a promising potential agent for the chemotherapy of prostate cancer.
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