Effect of titanium on the primary radiation damage and swelling of vanadium-titanium alloys

In this paper, a molecular dynamic study of the atomic displacement cascade development in pure vanadium and V-Ti alloys with titanium concentrations of 4, 8, and 16% is carried out for energies of a primary knocked-out atom of 5, 10, and 20 keV. The interactions between atoms in the V-Ti system are specified in the framework of a method developed earlier for modeling systems with metallic and covalent types of chemical bon

Molecular dynamics simulation of primary radiation damage in vanadium and alloy V-4Ti

The interatomic interaction in V and alloy V-4Ti was described on the base of modern potentials of interatomic interactions which took into account the interaction of screened ions at small interatomic distances and allowed to simulate correctly radiation damage. The main characteristics of atomic displacement cascades in simulated crystallites were calculated: the number of defects at different stages of cascade development, the size of the radiation-damaged regions, and an analysis of the estimation of the number, types and sizes of the surviving radiation defects in crystallites. The results obtained are compared for vanadium and alloy V-4T

Nanovoids in glasses and polymers probed by positron annihilation lifetime spectroscopy

Nanovoids in As2S3-based glasses (As 2S3, (As2S3)85Ag 15, and (As2S3)85(AgI) 15), a polymer and a As2S3-polymer nanocomposite were studied using the positron annihilation lifetime spectroscopy (PALS) technique. After computer treatment of the PALS data recorded, it was found that only two components τ 1 (short-lived) near 0.2 ns and τ 2 (long-lived) near 0.4 ns are resolved for the As 2S3-based glasses. At the same time, in the case of the polymer sample two components τ 2 near 0.3 ns and τ 3 (pick-off annihilation of ortho-positronium) near 2.8 ns were detected, while for the As2S3-polymer nanocomposite three components τ 1 near 0.2-0.3 ns, τ 2 near 0.4-0.5 ns and τ 3 near 2.4 ns were established. The volume of nanovoids in the materials studied was determined, and the fractional free volumes of the As2S3-polymer nanocomposite and the polymer matrix were compared. The results obtained are important to utilize As2S 3-based glasses and polymer nanocomposites for advanced sensor applications. © 2011 Springer Science+Business Media B.V

Doppler broadening of the annihilation line study of organic-inorganic hybrid ureasil-based composites

© Springer Science+Business Media Dordrecht 2015. The organic-inorganic hybrid ureasil-based composites, containing polyether chains covalently linked to a silica framework through urea bridges, referred as ureasilicates or ureasils, and semiconducting As2S3clusters, are investigated using Doppler broadening of annihilation line technique. It is established that the Doppler S and W parameters show significant structural difference between the pure ureasil and the As2S3-ureasil composites, the effect is more essential as the loading fraction of As2S3increases. The new Doppler broadening results obtained in this work are found to be in consistent with the earlier reported results of positron annihilation lifetime measurements of the same materials

New organic-inorganic hybrid ureasil-based polymer and glass-polymer composites with ion-implanted silver nanoparticles

The micro-/nanoscopic structure of the hybrid organic-inorganic materials, based on polyether chains covalently linked to a silica framework through urea bridges, referred as ureasilicates or ureasils, and As2S3-ureasil composites with ion-implanted Ag nanoparticles is investigated. The formation of Ag nanoparticles is confirmed using optical transmission (surface plasmon resonance band of Ag nanoparticles) at ion-implantation doses of 2.5×1016 and 5.0×1016 ion/cm2 on the example of ureasil. It is established with scanning electron microscopy that incorporation of the As2S3 clusters into ureasil assists to ion-synthesis of Ag nanoparticles in polymer matrix, more effectively at higher doses of ion-implantation and for silver containing (As2S3)95Ag5-ureasil composite. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

A comparative study between children and adults with bacterial neuroinfections

Abstract Introduction: Bacterial meningitis is an acute purulent infection of the meninges. There are significant differences in the etiological spectrum, clinical course and outcome of bacterial meningitis in the age groups, and their recognition is important for early diagnosis and adequate therapy. Aim: The study aims to determine the differences in the etiology and clinical presentation of bacterial meningitis between children and adults. Materials and methods: The study included 90 patients (25 children and 65 adults) with bacterial neuroinfection admitted to St George University Hospital, Plovdiv between January 1, 2016 and September 31, 2019. We applied epidemiological and clinical analysis, microbiological and statistical methods. Results: In adults, the most common etiological agent was Streptococcus pneumoniae (20%), followed by Staphylococcus spp. (18.5%), Listeria monocytogenes (12.3%), Streptococcus spp. (3.1%), Haemophilus influenzae (3.1%), Klebsiella pneumoniae (1.5%), and Mycobacterium tuberculosis (1.5%). The etiological structure in children was different: Neisseria meningitidis (20%), Streptococcus pneumoniae (16%), Klebsiella pneumoniae (8%), Enterococcus faecium (8%), Streptococcus salivarius (4%), and Mycobacterium tuberculosis (4%). In 40% of the cases, both children and adults, the causative agent was not identified. Conclusions: Regarding the clinical presentation, a statistical significance between the age groups was found with headache and alterations in consciousness, more commonly seen in adults, while vomiting, ear pain was more common in children (p<0.05). Concomitant otitis, sinusitis, pneumonia, and sepsis were often observed. The mortality rate was much higher in adults (43%) when compared with children (8%)

Release of Lungworm Larvae from Snails in the Environment: Potential for Alternative Transmission Pathways

Background: Gastropod-borne parasites may cause debilitating clinical conditions in animals and humans following the consumption of infected intermediate or paratenic hosts. However, the ingestion of fresh vegetables contaminated by snail mucus and/or water has also been proposed as a source of the infection for some zoonotic metastrongyloids (e.g., Angiostrongylus cantonensis). In the meantime, the feline lungworms Aelurostrongylus abstrusus and Troglostrongylus brevior are increasingly spreading among cat populations, along with their gastropod intermediate hosts. The aim of this study was to assess the potential of alternative transmission pathways for A. abstrusus and T. brevior L3 via the mucus of infected Helix aspersa snails and the water where gastropods died. In addition, the histological examination of snail specimens provided information on the larval localization and inflammatory reactions in the intermediate host. Methodology/Principal Findings: Twenty-four specimens of H. aspersa received ~500 L1 of A. abstrusus and T. brevior, and were assigned to six study groups. Snails were subjected to different mechanical and chemical stimuli throughout 20 days in order to elicit the production of mucus. At the end of the study, gastropods were submerged in tap water and the sediment was observed for lungworm larvae for three consecutive days. Finally, snails were artificially digested and recovered larvae were counted and morphologically and molecularly identified. The anatomical localization of A. abstrusus and T. brevior larvae within snail tissues was investigated by histology. L3 were detected in the snail mucus (i.e., 37 A. abstrusus and 19 T. brevior) and in the sediment of submerged specimens (172 A. abstrusus and 39 T. brevior). Following the artificial digestion of H. aspersa snails, a mean number of 127.8 A. abstrusus and 60.3 T. brevior larvae were recovered. The number of snail sections positive for A. abstrusus was higher than those for T. brevior. Conclusions: Results of this study indicate that A. abstrusus and T. brevior infective L3 are shed in the mucus of H. aspersa or in water where infected gastropods had died submerged. Both elimination pathways may represent alternative route(s) of environmental contamination and source of the infection for these nematodes under field conditions and may significantly affect the epidemiology of feline lungworms. Considering that snails may act as intermediate hosts for other metastrongyloid species, the environmental contamination by mucus-released larvae is discussed in a broader context

Dwarf Copper-Gold Porphyry Deposits of the Buchim-Damjan-Borov Dol Ore District, Republic of Macedonia (FYROM)

The metallogenic aspects, tectonic setting, magmatism, structure, and composition of Au-and Ag-bearing porphyry copper deposits in the Buchim-Damjan-Borov Dol ore district and their genetic features are considered and compared with earlier published data. Special attention is paid to supergene gold in heavy concentrate halos of the Borov Dol deposit. The total Cu reserves of the deposits discussed in this paper do not exceed 150 kt. The Buchim deposit likely is the world's smallest deposit of this type currently involved in mining. A comprehensive study of these dwarf porphyry copper deposits is undertaken to answer questions on the conditions of their formation. How do they differ from formation conditions of giant deposits

Алифатические углеводороды во взвеси снежно-ледяного покрова Белого моря

There are presented the results of multiyear research (2010, 2012 and 2015 and 2016) of aliphatic hydrocarbons and suspended matter in snow-ice cover of two regions of the White Sea: the Rugozerskaya bay (near the biological station of Moscow state University, the periphery of the Kandalaksha Bay) and the mouth of the Northern Dvina (near Archangelsk). Due to the atmospheric pollution in the heating season, hydrocarbon concentration increases, especially in the mouth of the Northern Dvina (up to 616 mg/l). In the ice, according to the conditions of ice formation, the concentration of the studied substances occurs in different parts of the core. In the top part of the ice the infl ow of hydrocarbons with snow infl uence hydrocarbon concentration and in the bottom part the main role plays the infl ow with under-ice water, in particular, a big role goes to the processes on the border ice-water. A comparison of the obtained data with the results of the research of hydrocarbons was produced in snow and ice in the background areas of the Arctic.Представлены результаты многолетних исследований (2010, 2012, 2015 и 2016 гг.) алифатических  углеводородов и взвешенного вещества в снежно-ледяном покрове двух районов Белого моря: губы Ругозерской (район биологической станции МГУ — ББС, периферия Кандалакшского залива) и устья Северной Двины (район г. Архангельска). В снеге, из-за загрязнения атмосферы в отопительный сезон, концентрации углеводородов повышались от февраля к марту, особенно в устье Северной Двины (до 616 мкг/л). Во льду в зависимости от условий льдообразования концентрирование углеводородов происходит в разных частях керна. В верхней части льда на содержание углеводородов оказывает влияние их поступление со снегом, а в нижней — из подледной воды, при этом большое значение приобретают процессы на границе лед–вода. Проведено сопоставление полученных данных с результатами изучения углеводородов в снеге и во льду в фоновых районах Арктики и Антарктики

Resurrection and redescription of Varestrongylus alces (Nematoda; Protostrongylidae), a lungworm of the Eurasian moose (Alces alces), with report on associated pathology

Varestrongylus alces, a lungworm in Eurasian moose from Europe has been considered a junior synonym of Varestrongylus capreoli, in European roe deer, due to a poorly detailed morphological description and the absence of a type-series. Methods Specimens used in the redescription were collected from lesions in the lungs of Eurasian moose, from Vestby, Norway. Specimens were described based on comparative morphology and integrated approaches. Molecular identification was based on PCR, cloning and sequencing of the ITS-2 region of the nuclear ribosomal DNA. Phylogenetic analysis compared V. alces ITS-2 sequences to these of other Varestrongylus species and other protostrongylids. Results Varestrongylus alces is resurrected for protostrongylid nematodes of Eurasian moose from Europe. Varestrongylus alces causes firm nodular lesions that are clearly differentiated from the adjacent lung tissue. Histologically, lesions are restricted to the parenchyma with adult, egg and larval parasites surrounded by multinucleated giant cells, macrophages, eosinophilic granulocytes, lymphocytes. The species is valid and distinct from others referred to Varestrongylus, and should be separated from V. capreoli. Morphologically, V. alces can be distinguished from other species by characters in the males that include a distally bifurcated gubernaculum, arched denticulate crura, spicules that are equal in length and relatively short, and a dorsal ray that is elongate and bifurcated. Females have a well-developed provagina, and are very similar to those of V. capreoli. Morphometrics of first-stage larvae largely overlap with those of other Varestrongylus. Sequences of the ITS-2 region strongly support mutual independence of V. alces, V. cf. capreoli, and the yet undescribed species of Varestrongylus from North American ungulates. These three taxa form a well-supported crown-clade as the putative sister of V. alpenae. The association of V. alces and Alces or its ancestors is discussed in light of host and parasite phylogeny and host historical biogeography. Varestrongylus alces is a valid species, and should be considered distinct from V. capreoli. Phylogenetic relationships among Varestrongylus spp. from Eurasia and North America are complex and consistent with faunal assembly involving recurrent events of geographic expansion, host switching and subsequent speciation. Cervidae, Cryptic species, Historical biogeography, ITS-2, Metastrongyloidea, Parasite biodiversity, Varestrongylinae, Varestrongylus capreoli, Verminous pneumoniapublishedVersio