The complete mitochondrial genome of the acid-tolerant fungus Penicillium ShG4C

AbstractComplete mitochondrial genome of the acid-tolerant fungus Penicillium ShG4C, isolated from oxidized sediments of an abandoned polymetallic mine site, has been sequenced using high-throughput sequencing approach. The mitochondrial genome represents a circular DNA molecule with size of 26,725bp. It encodes a usual set of mitochondrial genes, including 15 protein coding genes, large and small ribosomal RNAs and 27 tRNA genes. All genes are located on H-strand DNA and transcribed in one direction. Taxonomic analysis based on concatenated sequences of mitochondrial proteins confirmed taxonomic position of this fungus within the genus Penicillium. The sequence of the complete mitochondrial genome of Penicillium ShG4C was deposited in DBBJ/EMBL/GenBank under accession number KX931017

Isolation, characterization, and metal response of novel, acid-tolerant Penicillium spp. from extremely metal-rich waters at a mining site in Transbaikal (Siberia, Russia)

The role of fungi in metal cycling in acidic environments has been little explored to date. In this study, two acid-tolerant and metal-resistant Penicillium isolates, strains ShG4B and ShG4C, were isolated from a mine site in the Transbaikal area of Siberia (Russia). Waters at the mine site were characterized by extremely high metal concentrations: up to 18 g l−1 Fe and >2 g l−1 each of Cu, Zn, Al, and As. Both isolates were identified as Penicillium spp. by phylogenetic analyses and they grew well in Czapek medium acidified to pH 2.5. Resistance to Cu, Cd, Ni, Co, and arsenate was in the range of 1–10 g l−1. Further experiments with Penicillium strain ShG4C demonstrated that growth in Cu-containing media was accompanied by the precipitation of Cu-oxalate (moolooite) and the formation of extracellular vesicles enriched in Cu on the mycelia. Vesicles were greatly reduced in size in Cd-containing media and were not formed in the presence of Ni or Co. Cd-oxalate was detected as a crystalline solid phase in Cd-exposed mycelia. Hydrated Nisulfate (retgersite) and Co-sulfate (bieberite) were detected in mycelia grown in the presence of Ni and Co, respectively. The results demonstrated that acid-tolerant and metal-resistant Penicillium constitute a component in extremophilic microbiomes, contributing to organic matter breakdown and formation of secondary solid phases at pH ranges found in acid rock drainage

The UV Effect on the Chemiresistive Response of ZnO Nanostructures to Isopropanol and Benzene at PPM Concentrations in Mixture with Dry and Wet Air

Towards the development of low-power miniature gas detectors, there is a high interest in the research of light-activated metal oxide gas sensors capable to operate at room temperature (RT). Herein, we study ZnO nanostructures grown by the electrochemical deposition method over Si/SiO$_{2}$ substrates equipped by multiple Pt electrodes to serve as on-chip gas monitors and thoroughly estimate its chemiresistive performance upon exposing to two model VOCs, isopropanol and benzene, in a wide operating temperature range, from RT to 350 °C, and LED-powered UV illumination, 380 nm wavelength; the dry air and humid-enriched, 50 rel. %, air are employed as a background. We show that the UV activation allows one to get a distinctive chemiresistive signal of the ZnO sensor to isopropanol at RT regardless of the interfering presence of H$_{2}$O vapors. On the contrary, the benzene vapors do not react with UV-illuminated ZnO at RT under dry air while the humidity’s appearance gives an opportunity to detect this gas. Still, both VOCs are well detected by the ZnO sensor under heating at a 200–350 °C range independently on additional UV exciting. We employ quantum chemical calculations to explain the differences between these two VOCs’ interactions with ZnO surface by a remarkable distinction of the binding energies characterizing single molecules, which is −0.44 eV in the case of isopropanol and −3.67 eV in the case of benzene. The full covering of a ZnO supercell by H$_{2}$O molecules taken for the effect’s estimation shifts the binding energies to −0.50 eV and −0.72 eV, respectively. This theory insight supports the experimental observation that benzene could not react with ZnO surface at RT under employed LED UV without humidity’s presence, indifference to isopropanol

Effect of functionalization on the electrical properties of laser-structured hybrid carbon nanomaterials

Background and Objectives: An urgent task of field emission electronics is to reduce the operating voltage in order to obtain an emission current of a given density. To solve this problem, an emitter with a low work function is needed. Carbon nanomaterials are promising candidates for the role of field emitters; however, to reduce the work function of electrons from these nanomaterials, it is necessary to functionalize their surface with other nanostructures with a low work function. In this work, we experimentally studied the effect of functionalization of lanthanum hexaboride (LaB6) with nanoparticles on the electrical properties of nanomaterials based on an array of carbon nanotubes (CNTs). Materials and Methods: Using the developed technology of laser exposure, a hybrid nanomaterial was created based on a vertical array of CNTs functionalized with LaB6 nanoparticles. Pulsed laser action on an array of CNTs with an energy density of 0.15 J/cm2 made it possible to shorten, align, and structure the upper ends of the nanotubes perpendicular to the substrate. Results: The effect of the formation of a hybrid nanostructure by binding LaB6 nanoparticles to the CNT surface has been experimentally established. Registration of the emission current-voltage characteristics of hybrid nanomaterials has shown a decrease in the total work function of the hybrid nanomaterial by 78% after functionalization with LaB6 nanoparticles. Conclusion: Based on the results obtained, it is predicted that CNT+LaB6 hybrid nanostructures have a great potential for application as nanomaterials for field emission electronics

2D Molybdenum Carbide MXenes for Enhanced Selective Detection of Humidity in Air

2D transition metal carbides and nitrides (MXenes) open up novel opportunities in gas sensing with high sensitivity at room temperature. Herein, 2D Mo2CTx flakes with high aspect ratio are successfully synthesized. The chemiresistive effect in a sub-mu m MXene multilayer for different organic vapors and humidity at 10(1)-10(4) ppm in dry air is studied. Reasonably, the low-noise resistance signal allows the detection of H2O down to 10 ppm. Moreover, humidity suppresses the response of Mo2CTx to organic analytes due to the blocking of adsorption active sites. By measuring the impedance of MXene layers as a function of ac frequency in the 10(-2)-10(6) Hz range, it is shown that operation principle of the sensor is dominated by resistance change rather than capacitance variations. The sensor transfer function allows to conclude that the Mo2CTx chemiresistance is mainly originating from electron transport through interflake potential barriers with heights up to 0.2 eV. Density functional theory calculations, elucidating the Mo2C surface interaction with organic analytes and H2O, explain the experimental data as an energy shift of the density of states under the analyte's adsorption which induces increasing electrical resistance

Flexible Membranes for Batteries and Supercapacitor Applications

Modern portable electronic devices, roll-up displays and wearable systems for personal multimedia devices require flexible energy storage devices [...

Liposome Drug Delivery System across Endothelial Plasma Membrane: Role of Distance between Endothelial Cells and Blood Flow Rate

This paper discusses specific features of the interactions of small-diameter liposomes with the cytoplasmic membrane of endothelial cells using in silico methods. The movement pattern of the liposomal drug delivery system was modeled in accordance with the conditions of the near-wall layer of blood flow. Our simulation results show that the liposomes can become stuck in the intercellular gaps and even break down when the gap is reduced. Liposomes stuck in the gaps are capable of withstanding a shell deformation of ~15% with an increase in liposome energy by 26%. Critical deformation of the membrane gives an impetus to drug release from the liposome outward. We found that the liposomes moving in the near-wall layer of blood flow inevitably stick to the membrane. Liposome sticking on the membrane is accompanied by its gradual splicing with the membrane bilayer. This leads to a gradual drug release inside the cell

Student-Centered Education in Context of Second-Language Learning

Recent higher education policy promotes multilingualism due to the process of globalization in all spheres of our life. The main focus of this article is on “student –centered learning” which claims to be one of the effective tools in the learning process. In this regard, the given research centers on the impact of adopting student-centered education in language acquisition. It is based on facilitating effective learning, which implies strong interaction between the learner and the teacher. This paper examines the structure of student-centered learning which is aimed at creating subjective experience of the learner but not training students` cognitive abilities. The paper aims to consider the notion “multicultural identity” of students which is considered to be the main consequence caused by learning one more foreign language. The authors of the research determined principles and outlined tasks which contribute to effective implementation of student-centered education in second language acquisition

Interaction of Co₃O₄ Nanocube with Graphene and Reduced Graphene Oxide: Adhesion and Quantum Capacitance

The composites on the base of Co3O4 and graphene are in demand in the field of portable, flexible energy storage devices due to their small size, lightweight, big specific capacitance, good cycle stability and appropriate capacitance retention. The synthesis of this material always starts from the treatment of graphene oxide, so as a result, experimenters receive Co3O4 nanocubes incorporated into reduced graphene oxide indicates the presence of different oxygen-containing groups in the compound. This fact may limit the advantages of the considered material. Our theoretical quantum chemical calculations show that the process of Co3O4 incorporation between reduced graphene oxide layers is more energetically favorable in comparison to pure graphene. However, the win in the quantum capacitance in the case of pure graphene is in the range of 300–500 F/g in dependence on the applied voltage. The obtained result may indicate the need for modification of the current methods of graphene/Co3O4 synthesis to improve its application in supercapacitors and lithium-ion batteries