bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Dynamics Simulations of DNA Adsorption on Graphene Oxide and Reduced Graphene Oxide-PEG-NH2 in the Presence of Mg2+ and Cl− ions
Authors: Muraru Sebastian , Samoila Cosmin G. , Slusanschi Emil I. , Burns Jorge S. , Ionita Mariana
Published: March 2020

Graphene and its functionalised derivatives are transforming the development of biosensors that are capable of detecting nucleic acid hybridization. Using a Molecular Dynamics (MD) approach, we explored single-stranded or double-stranded deoxyribose nucleic acid (ssDNA or dsDNA) adsorption on two graphenic species: graphene oxide (GO) and reduced graphene oxide functionalized with aminated polyethylene glycol (rGO-PEG-NH2). Innovatively, we included chloride (Cl−) and magnesium (Mg2+) ions that influenced both the ssDNA and dsDNA adsorption on GO and rGO-PEG-NH2 surfaces. Unlike Cl−, divalent Mg2+ ions formed bridges between the GO surface and DNA molecules, promoting adsorption through electrostatic interactions. For rGO-PEG-NH2, the Mg2+ ions were repulsed from the graphenic surface. The subsequent ssDNA adsorption, mainly influenced by electrostatic forces and hydrogen bonds, could be supported by π–π stacking interactions that were absent in the case of dsDNA. We provide a novel insight for guiding biosensor development.
Hard Quasicrystalline Coatings Deposited by HVOF Thermal Spray to Reduce Ice Accretion in Aero-Structures Components
Authors: Mora J. , García P. , Muelas R. , Agüero A.
Published: March 2020

Weather hazards, in particular icing conditions, are an important contributing factor in aviation accidents and incidents worldwide. Many different anti-icing strategies are currently being explored to find suitable long-lasting solutions, such as surface engineering, which can contribute to reduce ice accumulation. Quasicrystals (QCs) are metallic materials, but with similar properties to those of ceramic materials, such as low thermal and electrical conductivities, and high hardness. In particular, QCs that have low surface energy are commercially used as coatings to replace polytetrafluoroethylene (PTFE), also known as Teflon, on frying pans, as they do not scratch easily. PTFE exhibits excellent anti-wetting and anti-icing properties and therefore QCs appear as good candidates to be employed as ice-phobic coatings. Al-based QCs have been applied by High Velocity Oxyfuel (HVOF) thermal spray on typically used aeronautic materials, such as Ti and Al alloys, as well as steels. The coatings have been characterized and evaluated, including the measurement of hardness, roughness, wetting properties, ice accretion behavior in an icing wind tunnel (IWT), and ice adhesion by a double lap shear test. The coatings were studied, both as-deposited, as well as after grinding, in order to study the effect of the surface roughness and morphology on the ice accretion and adhesion properties. The QC coating was compared with PTFE and two polyurethane (PU)-based commercial paints, one of them known to have anti-icing properties, and the results indicate an ice accretion reduction relative to these two materials, and ice adhesion lower than bare AA6061-T6, or the PU paint in the ground version of one of the two QCs. Since the QC coatings are hard (GPa Vickers hardness > 5), a durable behavior is expected.
Pulsed Electrodeposition for Copper Nanowires
Authors: Vuong Duc-Thinh , Hoang Ha-My , Tran Nguyen-Hung , Kim Hyun-Chul
Published: March 2020

Copper nanowires (Cu NWs) are a promising alternative to indium tin oxide (ITO), for use as transparent conductors that exhibit comparable performance at a lower cost. Furthermore, Cu NWs are flexible, a property not possessed by ITO. However, the Cu NW-based transparent electrode has a reddish color and tends to deteriorate in ambient conditions due to the oxidation of Cu. In this paper, we propose a pulsed-current (PC) plating method to deposit nickel onto the Cu NWs in order to reduce oxidation over a 30-day period, and to minimize the sheet resistance. Additionally, the effects of the pulse current, duty cycle, and pulse frequency on the performance of the Cu–Ni (copper–nickel) NW films have also been investigated. As a result, the reddish color of the electrode was eliminated, as oxidation was completely suppressed, and the sheet resistance was reduced from 35 Ω/sq to 27 Ω/sq. However, the transmittance decreased slightly from 86% to 76% at a wavelength of 550 nm. The Cu–Ni NW electrodes also exhibited excellent long-term cycling stability after 6000 bending cycles. Our fabricated Cu–Ni electrodes were successfully applied in flexible polymer-dispersed liquid crystal smart windows.
Terbium-Tetracarboxylate Framework as a Luminescent Probe for the Selective Detection of Nitrofurazone
Authors: Li Qipeng , Shen Yanqiong , Zhao Junsong , Zhang Zejun , Qian Jinjie
Published: March 2020

A novel terbium-tetracarboxylate framework with the 5,5’-(diazene-1,2-iyl)diisophthalic acid (H4abtc) ligand, formulated as [Tb(Habtc)(DMSO)(H2O)2]n (ZTU-5), has been synthesized and structurally characterized. ZTU-5 features a 2D-layered structure constructed by the binuclear terbium secondary building units (SBUs) and abtc4– ligand, which can be further expanded into a 3D-supramolecular framework by the hydrogen bond interactions. In addition, the magnetic and fluorescence properties of ZTU-5 are investigated and ZTU-5 exhibits highly selective and sensitive detection of nitrofurazone (NZF).
DNA Barcoding for Delimitation of Putative Mexican Marine Nematodes Species
Authors: Martínez-Arce Arely , De Jesús-Navarrete Alberto , Leasi Francesca
Published: March 2020

Nematode biodiversity is mostly unknown; while about 20,000 nematode species have been described, estimates for species diversity range from 0.1 to 100 million. The study of nematode diversity, like that of meiofaunal organisms in general, has been mostly based on morphology-based taxonomy, a time-consuming and costly task that requires well-trained specialists. This work represents the first study on the taxonomy of Mexican nematodes that integrates morphological and molecular data. We added eleven new records to the Mexican Caribbean nematode species list: Anticomidae sp.1, Catanema sp.1, Enoploides gryphus, Eurystomina sp.1, Haliplectus bickneri, Metachromadora sp.1, Odontophora bermudensis, Oncholaimus sp.1, Onyx litorale, Proplatycoma fleurdelis, and Pontonema cf. simile. We improved the COI database with 57 new sequences from 20 morphotypes. All COI sequences obtained in this work are new entries for the international genetic databases GenBank and BOLD. Among the studied sites, we report the most extensive species record (12 species) at Cozumel. DNA barcoding and species delineation methods supported the occurrence of 20 evolutionary independent entities and confirmed the high taxonomic resolution of the COI gene. Different approaches provided consistent results: ABGD and mPTP methods disentangled 20 entities, whereas Barcode Index Numbers (BINs) recovered 22 genetic species. Results support DNA barcoding being an efficient, fast, and low-cost method to integrate into morphological observations in order to address taxonomical shortfalls in meiofaunal organisms.
Simultaneous Metabarcoding of Eukaryotes and Prokaryotes to Elucidate the Community Structures within Tardigrade Microhabitats
Authors: Arakawa Kazuharu
Published: March 2020

Tardigrades are microscopic invertebrates that can withstand complete desiccation, but their interspecies interactions with prokaryotes and eukaryotes within their microhabitat remain relatively unexplored. Here, I utilized combined metabarcoding of eukaryotes and prokaryotes to simultaneously identify entire community structures within xeric and mesic mosses that harbor tardigrades. The populations of organisms within the microecosystems were successfully determined in 45 xeric moss samples and 47 mesic moss samples. Organismal composition was largely consistent regardless of the moss/lichen substrate, but significantly varied in the two tested locations, possibly because of the differences in environmental humidity. Xeric mosses containing xerophilic tardigrades and other anhydrobiotic invertebrates tended to have significantly limited biological diversity and prokaryotic population dominated by cyanobacteria, suggesting a selection due to extreme desiccation. A combined metabarcoding approach to identify both eukaryotes and prokaryotes can successfully elucidate community structures within microscopic ecosystems, and this can be a potential approach to study the microecology of meiofauna, including tardigrades.
Do Invasive Mosquito and Bird Species Alter Avian Malaria Parasite Transmission?
Authors: Martínez-de la Puente Josué , Díez-Fernández Alazne , Montalvo Tomás , Bueno-Marí Rubén , Pangrani Quentin , Soriguer Ramón C. , Senar Juan Carlos , Figuerola Jordi
Published: March 2020

Alien mosquito and vertebrate host species may create novel epidemiological scenarios for the transmission of pathogens naturally circulating in the invaded area. The exotic Monk parakeet (Myiopsitta monachus) has established populations in Europe and is currently considered an invasive pest. Due to their high abundance in urban areas, Monk parakeets could be involved in the transmission of pathogens, potentially affecting wildlife and livestock. To test this hypothesis, we determined the prevalence and diversity of three vector-borne parasites, namely Plasmodium, Haemoproteus and Leucocytozoon, in Monk parakeets from Barcelona. Many areas of southern Europe shelter high densities of the invasive Asian tiger mosquito Aedes albopictus, which in addition to native mosquito species could affect the transmission of mosquito-borne parasites, such as avian Plasmodium. Thus, we also sampled mosquitoes in the area to trace their blood-feeding hosts and determine the presence of Plasmodium parasites. Monk parakeets were neither infected by Plasmodium nor by Haemoproteus parasites, and only five individuals (3.13%; n = 160) were infected by Leucocytozoon. Monk parakeets were bitten by Culiseta longiareolata and represented 9.5% of Culex pipiens blood meals. The invasive Ae. albopictus showed a clear anthropophilic feeding pattern, with humans dominating its diet. Three Plasmodium lineages were detected in pools of Cx pipiens. These results suggest that Plasmodium circulating in the area cannot develop in the invasive Monk parakeet, in spite of the relatively high fraction of native mosquito vectors feeding on this species in its invaded distribution range.
Electrochemical Reduction of CO2: Overcoming Chemical Inertness at Ambient Conditions
Authors: Perez Ana Cristina , Diaz-Perez Manuel Antonio , Serrano-Ruiz Juan Carlos
Published: March 2020

Electroreduction allows for the transformation of a chemically inert molecule such as CO2 into a wide variety of useful carbon products. Unlike other approaches operating at higher temperatures, electrochemical reduction holds great promise since it achieves reduction under ambient conditions, thereby providing more control over the reaction selectivity. By controlling basic parameters such as the potential and the composition of the electrode, CO2 can be transformed into a variety of products including carbon monoxide, syngas (CO/H2), methane, and methanol. This reduction process takes place without external hydrogen, since water can be used as a source of both electrons and protons. Furthermore, this technology, when combined with renewable wind- or solar-derived electricity, has the potential to serve as a storage system for excess electricity. Despite these advantages, a number of challenges need to be overcome before reaching commercialization. New (and cheaper) electrocatalyst formulations with high faradaic selectivities are required. Impressive progress has been made on carbon-doped materials, which, in certain cases, have outperformed expensive noble metal-based materials. Research is also needed on new electrochemical reactor configurations able to overcome kinetic/mass transport limitations, which are crucial to reduce overpotentials. Fine control over the nature of the active sites and the reaction conditions is important to avoid parasitic reactions such as the hydrogen evolution reaction (HER), and therefore increases the faradaic efficiency towards the desired products.
Laplacian Support Vector Machine for Vibration-Based Robotic Terrain Classification
Authors: Shi Wenlei , Li Zerui , Lv Wenjun , Wu Yuping , Chang Ji , Li Xiaochuan
Published: March 2020

The achievement of robot autonomy has environmental perception as a prerequisite. The hazards rendered from uneven, soft and slippery terrains, which are generally named non-geometric hazards, are another potential threat reducing the traversing efficient, and therefore receiving more and more attention from the robotics community. In the paper, the vibration-based terrain classification (VTC) is investigated by taking a very practical issue, i.e., lack of labels, into consideration. According to the intrinsic temporal correlation existing in the sampled terrain sequence, a modified Laplacian SVM is proposed to utilise the unlabelled data to improve the classification performance. To the best of our knowledge, this is the first paper studying semi-supervised learning problem in robotic terrain classification. The experiment demonstrates that: (1) supervised learning (SVM) achieves a relatively low classification accuracy if given insufficient labels; (2) feature-space homogeneity based semi-supervised learning (traditional Laplacian SVM) cannot improve supervised learning’s accuracy, and even makes it worse; (3) feature- and temporal-space based semi-supervised learning (modified Laplacian SVM), which is proposed in the paper, could increase the classification accuracy very significantly.
Experimental Verification of the Inverse Method of the Heat Transfer Coefficient Calculation
Authors: Duda Piotr , Konieczny Mariusz
Published: March 2020

The purpose of this work is to formulate a method which can be used to solve nonlinear inverse heat conduction problems and to calculate the heat transfer coefficient distribution on the unknown boundary. The domain under consideration is divided into control volumes in polar coordinates, and heat balance equations are written. Based on temperature transients measured in selected points on the outer surface, temperature values in other points of the domain are determined. Finally, the heat transfer coefficient distribution on the inner surface with the unknown boundary condition is calculated from the presented heat balance equation. The proposed inverse method was verified experimentally using a collector that is part of a semi-industrial laboratory system. This collector is a horizontal, cylindrical thick-walled tank with flat side walls with outlets that enable oil supply and removal. Each side wall has an additional connector to ensure venting. The calculations made it possible to identify the phenomena occurring inside the collector during the experiment. The transient temperature distribution identified by the proposed inverse method was verified by a comparison of the calculated and the measured temperature transients in points inside the collector wall. Very good agreement is observed between the calculated and the measured temperature transients, which confirms the correctness of the identification. This proposed inverse method of the temperature and the heat transfer coefficient calculation is fast enough to apply in online thermal state monitoring systems. The proposed algorithm presented in this paper can easily be implemented industrially.
Studies on the Gasification Performance of Sludge Cake Pre-Treated by Hydrothermal Carbonization
Authors: Lee Sang Yeop , Park Se Won , Alam Md Tanvir , Jeong Yean Ouk , Seo Yong-Chil , Choi Hang Seok
Published: March 2020

Proper treatment and careful management of sewage sludge are essential because its disposal can lead to adverse environmental impacts such as public health hazards, as well as air, soil, and water pollution. Several efforts are being made currently not only to safely dispose of sewage sludge but also to utilize it as an energy source. Therefore, in this study, initiatives were taken to valorize sewage sludge cake by reducing the moisture content and increasing the calorific value by applying a hydrothermal treatment technique for efficient energy recovery. The sludge cake treated at 200 °C for 1 h was found to be the optimum condition for hydrothermal carbonization, as, in this condition, the caloric value of the treated sludge increased by 10% and the moisture content removed was 20 wt.%. To recover energy from the hydrothermally treated sludge, a gasification technology was applied at 900 °C. The results showed that the product gas from hydrothermally treated sludge cake had a higher lower heating value (0.98 MJ/Nm3) and higher cold gas efficiency (5.8%). Furthermore, compared with raw sludge cake, less tar was generated during the gasification of hydrothermally treated sludge cake. The removal efficiency was 28.2%. Overall results depict that hydrothermally treated sewage sludge cake could be a good source of energy recovery via the gasification process.
3D Mapping of the Sprinkler Activation Time
Authors: Węgrzyński Wojciech , Krajewski Grzegorz , Tofiło Piotr , Jahn Wolfram , Król Aleksander , Król Małgorzata
Published: March 2020

Sprinkler activation is one of the key events defining the course of a compartment fire. The time when activation occurs is commonly used in the determination of the design fire scenario, which is the cornerstone of the design of building fire safety features. A well-known model of sprinkler activation (response time index (RTI) model) was introduced into the numerical scheme of the ANSYS Fluent computational fluid dynamics (CFD) package. The novel way in which the model is used is the calculation of the time for sprinkler activation within each discrete cell of the domain. The proposed novel approach was used in a case-study to assess the effects of comfort mode natural ventilation on a sprinkler’s activation pattern. It was found that hinged vents in the comfort mode had a significant effect on sprinkler activation, both in terms of delaying it as well as limiting the total number of cells in which the sprinkler would have activated. In some scenarios with a hinged vent, no activation was observed in the central point of the vent, possibly indicating problems with the autonomous triggering of the fire mode of such a device. It was also found that the RTI and C (related to the conductive transport of sprinkler fitting) parameter values had a moderate influence on sprinkler activation time—only for high-temperature sprinklers (≥ 141 °C). This study shows the applicability of the 3D activation time mapping for research focused on the fire safety of sprinkler-protected compartments and for the performance-based approach to sprinkler system design. Even though the RTI model is the industry standard for the determination of sprinkler response, the model implementation in ANSYS Fluent was not validated. This means that sources of uncertainty, mainly connected with the determination of flow velocity and temperature are not known, and the model should be used with caution. An in-depth validation is planned for subsequent studies.
Long-term Static and Operational Reserves Assessment Considering Operating and Market Agreements Representation to Multi-Area Systems
Authors: Vieira Pedro , Rosa Mauro , Bremermann Leonardo , Pequeno Erika , Miranda Sandy
Published: March 2020

This paper exploits different computational modelling to assess long-term static and operating reserves to multi-area systems. To deal with intermittent renewable generation and other types of technologies, this paper is proposing a flexible simulation model able to capture not only technological innovation of power system components and their electric and energetic behaviors, but also operational procedures and market agreements representations to yield planning insights about the performance of the multi-area systems. Results based on two modified test systems with a variate of generation technologies and interconnections are used to show the potential of the simulation model.
Underfrequency Load Shedding: An Innovative Algorithm Based on Fuzzy Logic
Authors: Małkowski Robert , Nieznański Janusz
Published: March 2020

In contemporary power systems, the load shedding schemes are typically based on disconnecting a pre-specified amount of load after the frequency drops below a predetermined value. The actual conditions at the time of disturbance may largely differ from the assumptions, which can lead to non-optimal or ineffective operation of the load shedding scheme. For many years, increasing the effectiveness of the underfrequency load shedding (UFLS) schemes has been the subject of research around the world. Unfortunately, the proposed solutions often require costly technical resources and/or large amounts of real-time data monitoring. This paper puts forth an UFLS scheme characterized by increased effectiveness in the case of large disturbances and reduced disconnected power in the case of small and medium disturbances compared to the conventional load-shedding solutions. These advantages are achieved by replacing time-consuming consecutive load dropping with the simultaneous load dropping mechanism and by replacing ineffective fixed-frequency activation thresholds independent of the state of the system with implicit adaptive thresholds based on fuzzy logic computations. The proposed algorithm does not require complex and costly technical solutions. The performance of the proposed scheme was validated using multivariate computer simulations. Selected test results are included in this paper.
Grid-Connected Photovoltaic Systems with Single-Axis Sun Tracker: Case Study for Central Vietnam
Authors: Ngo Xuan Cuong , Nguyen Thi Hong , Do Nhu Y , Nguyen Duc Minh , Vo Dai-Viet N. , Lam Su Shiung , Heo Doyeon , Shokouhimehr Mohammadreza , Nguyen Van-Huy , Varma Rajender S. , Kim Soo Young , Le Quyet Van
Published: March 2020

Recently, the demand for small grid-connected photovoltaic (PV) systems has been rapidly increasing; this is due to the reduction in the costs of grid-connected storage systems as compared to those of the stand-alone ones. Notably, the performance of the solar tracking system is not only depending on the types but also the region that they are set up and used. To understand how solar tracking systems work globally, we need to know their performance in each country and even the different parts of a country. In this study, two grid-connected PV systems with 250 W solar modules were used to investigate the efficient improvement of a single-axis sun tracking system in Central Vietnam. First, a mechanical tracking device with a linear actuator and a controller was designed and then its performance was comprehensively investigated with a grid-connected PV system. In addition to evaluating the energy gain by the tracking system, this study also considered the energy consumption of the linear actuator with its controller and a small grid-connected PV system; this has generally been omitted in previous works. Experimental results indicate that the total energy consumption of the tracking system was approximately 2–8% of the energy generated by the grid-connected PV system. The maximum overall energy generation was confirmed to have increased by up to 30.3% on a sunny day upon using the proposed tracking system; further, the net energy gain by using the sun tracker was ascertained to be 15.2% in average weather conditions. Based on the success of this work, we will keep experimenting with other parts of Vietnam. Also, we will collaborate with colleagues in other countries to create a guideline for understanding and using the solar tracker regionally and globally.
An Accurate Discrete Current Controller for High-Speed PMSMs/Gs in Flywheel Applications
Authors: Zhang Xiang , Chen Yunlong , Mollet Yves , Yang Jiaqiang , Gyselinck Johan
Published: March 2020

High-speed Permanent-Magnet Synchronous Motors/Generators (PMSMs/Gs) in a Flywheel Energy Storage System (FESS) are faced with high cross-coupling voltages and low switching-to-fundamental frequency ratios. High cross-coupling voltages between d-q axis current loops lead to transient current errors, which is more serious at lower switching-to-fundamental-frequency ratios. If the delays are not properly considered during the current controller design in a digital control system, the low switching-to-fundamental-frequency ratios may result in oscillatory or unstable responses. In this study, an accurate discrete current controller for high-speed PMSMs/Gs is proposed based on an accurate discrete model that takes the phase and magnitude errors generated during the sampling period into consideration, and an Extended State Observer (ESO) is applied to estimate and compensate the back EMF error. The cross-coupling problem is well settled, and the current loop dynamic at lower switching-to-fundamental frequency ratios is improved. Finally, the proposed discrete controller is validated on a 12,000 rpm PMSM/G prototype.
Experimental Realization of Heavily p-doped Half-Heusler CoVSn Compound
Authors: Hooshmand Zaferani Sadeq , Darebaghi Alireza , Hong Soon-Jik , Vashaee Daryoosh , Ghomashchi Reza
Published: March 2020

Hypothetical half-Heusler (HH) ternary alloy of CoVSn has already been computationally investigated for possible spintronics and thermoelectric applications. We report the experimental realization of this compound and the characterizations of its thermoelectric properties. The material was synthesized by a solid-state reaction of the stoichiometric amounts of the elements via powder metallurgy (30 h mechanical milling and annealing at 900 °C for 20 h) and spark plasma sintering (SPS). The temperature-dependent ternary thermodynamic phase diagram of Co-V-Sn was further calculated. The phase diagram and detailed analysis of the synthesized material revealed the formation of the non-stoichiometry HH CoVSn, mixed with the binary intermetallic phases of SnV3, Co2Sn, and Co3V. The combination of X-ray diffraction, energy-dispersive X-ray spectroscopy, and thermoelectric transport properties confirmed the formation of a multi-phase compound. The analysis revealed the predicted thermoelectric features (zT = 0.53) of the highly doped CoVSn to be compromised by the formation of intermetallic phases (zT ≈ 0.007) during synthesis. The additional phases changed the properties from p- to overall n-type thermoelectric characteristics.
Estimating the Impact of Arc Furnaces on the Quality of Power in Supply Systems
Authors: Łukasik Zbigniew , Olczykowski Zbigniew
Published: March 2020

Arc furnaces, due to their high unit power and load nature, belong to the receivers affecting the power quality. A dynamically changing electric arc is the main source of disturbances generated by arc devices. This current article presents the results of model tests of disturbances caused by arc furnaces. It also presents the attempts to estimate the power supply conditions for arc furnaces, so that they do not generate unacceptable disturbances to the power system. Various models of the electric arc are proposed. The values of the elements making up the furnace supply system were based on actual parameters. In these networks, measurements of electricity quality indicators were carried out, which allowed us to refer to the obtained results of model tests with the real values. Accordingly, to the real conditions, the values of the short-circuit power of the network and the power of furnace transformers were also adopted in the tests.
Second-Order Approximation of the Seismic Reflection Coefficient in Thin Interbeds
Authors: Yang Zhen , Lu Jun
Published: March 2020

As most of the lithostratigraphic reservoirs in China are thin interbeds, the study of seismic responses in thin interbeds is an integral part of lithologic reservoir exploration. However, at present, the research on seismic reflection coefficients of thin interbeds in exploration seismology is still weak, which leads to the lack of theoretical basis for the subsequent interpretation of amplitude variation with offset (AVO) related to thin interbed. To solve this problem, in this paper, we proposed second-order approximate equations of the seismic reflection coefficients in thin-bed and thin-interbed layers. Under the assumption of a small impedance contrast in layered media, we made a second-order approximation with a more evident physical meaning to the reflection coefficient calculation method proposed by Kennett. Then, based on the test of the single thin-layer theoretical model, it was confirmed that the second-order approximation equation of the PP-wave (reflected compressional wave) is accurate at incident angles less than 30°, and that of the PS-wave (converted shear wave) is accurate at wider incident angles. Finally, based on the single-thin-bed equations, the approximate equations of seismic reflection coefficients in thin interbeds were established, the validity of which was verified by the theoretical model. Our equations will be applicable to the calculation of PP- and PS-wave reflection coefficients in thin interbeds where internal multiples are difficult to suppress and transmission loss is hard to accurately compensate. This lays a theoretical foundation for improving the seismic prediction accuracy of lithologic reservoirs.
A New Configuration of Three-Level ZSI Using Transistor Clamped Topology
Authors: Sonar Santosh
Published: March 2020

In this paper, a three-level ZSI (impedance source inverter) based on transistor clamped theory is proposed. It uses the least number of switch counts and associated gate circuitry among all existing topologies of three-level ZSI without any performance degradation. The existing three-level ZSI topologies require three power switches to be turned ON for upper-lower shoot-through (ULST), and four power switches to be turned ON for full dc-link shoot-through (FST). However, with the proposed configuration, upper–lower shoot-through (ULST) and full dc-link shoot-through (FST) is inserted by turning ON only two power semiconductors. A comparison between diode clamped, transistor clamped, and t-type is presented. The proposed topology can realize any of the existing sine-triangle- or space vector-based PWM (pulse width modulation) schemes, and all existing configurations of three-level ZSI can merge into the proposed inverter configuration.
Effect of Salt Concentration, Solvent Donor Number and Coordination Structure on the Variation of the Li/Li+ Potential in Aprotic Electrolytes
Authors: Kottam P. K. R. , Dongmo S. , Wohlfahrt-Mehrens M. , Marinaro M.
Published: March 2020

The use of concentrated aprotic electrolytes in lithium batteries provides numerous potential applications, including the use of high-voltage cathodes and Li-metal anodes. In this paper, we aim at understanding the effect of salt concentration on the variation of the Li/Li+ Quasi-Reference Electrode (QRE) potential in Tetraglyme (TG)-based electrolytes. Comparing the obtained results to those achieved using Dimethyl sulfoxide DMSO-based electrolytes, we are now able to take a step forward and understand how the effect of solvent coordination and its donor number (DN) is attributed to the Li-QRE potential shift. Using a revised Nernst equation, the alteration of the Li redox potential with salt concentration was determined accurately. It is found that, in TG, the Li-QRE shift follows a different trend than in DMSO owing to the lower DN and expected shorter lifespan of the solvated cation complex.
Mechanical Characteristics of the Fine Roots of Two Broadleaved Tree Species from the Temperate Caspian Hyrcanian Ecoregion
Authors: Deljouei Azade , Abdi Ehsan , Schwarz Massimiliano , Majnounian Baris , Sohrabi Hormoz , Dumroese R. Kasten
Published: March 2020

In view of the important role played by roots against shallow landslides, root tensile force was evaluated for two widespread temperate tree species within the Caspian Hyrcanian Ecoregion, i.e., Fagus orientalis L. and Carpinus betulus L. Fine roots (0.02 to 7.99 mm) were collected from five trees of each species at three different elevations (400, 950, and 1350 m a.s.l.), across three diameter at breast height (DBH) classes (small = 7.5–32.5 cm, medium = 32.6–57.5 cm, and large =57.6–82.5 cm), and at two slope positions relative to the tree stem (up- and down-slope). In the laboratory, maximum tensile force (N) required to break the root was determined for 2016 roots (56 roots per each of two species x three sites x three DBH classes x two slope positions). ANCOVA was used to test the effects of slope position, DBH, and study site on root tensile force. To obtain the power-law regression coefficients, a nonlinear least square method was used. We found that: 1) root tensile force strongly depends on root size, 2) F. orientalis roots are stronger than C. betulus ones in the large DBH class, although they are weaker in the medium and small DBH classes, 3) root mechanical resistance is higher upslope than downslope, 4) roots of the trees with larger DBH were the most resistant roots in tension in compare with roots of the medium or small DBH classes, and 5) the root tensile force for both species is notably different from one site to another site. Overall, our findings provide a fundamental contribution to the quantification of the protective effects of forests in the temperate region.
Structural Variation of the X Chromosome Heterochromatin in the Anopheles gambiae Complex
Authors: Sharma Atashi , Kinney Nicholas A. , Timoshevskiy Vladimir A. , Sharakhova Maria V. , Sharakhov Igor V.
Published: March 2020

Heterochromatin is identified as a potential factor driving diversification of species. To understand the magnitude of heterochromatin variation within the Anopheles gambiae complex of malaria mosquitoes, we analyzed metaphase chromosomes in An. arabiensis, An. coluzzii, An. gambiae, An. merus, and An. quadriannulatus. Using fluorescence in situ hybridization (FISH) with ribosomal DNA (rDNA), a highly repetitive fraction of DNA, and heterochromatic Bacterial Artificial Chromosome (BAC) clones, we established the correspondence of pericentric heterochromatin between the metaphase and polytene X chromosomes of An. gambiae. We then developed chromosome idiograms and demonstrated that the X chromosomes exhibit qualitative differences in their pattern of heterochromatic bands and position of satellite DNA (satDNA) repeats among the sibling species with postzygotic isolation, An. arabiensis, An. merus, An. quadriannulatus, and An. coluzzii or An. gambiae. The identified differences in the size and structure of the X chromosome heterochromatin point to a possible role of repetitive DNA in speciation of mosquitoes. We found that An. coluzzii and An. gambiae, incipient species with prezygotic isolation, share variations in the relative positions of the satDNA repeats and the proximal heterochromatin band on the X chromosomes. This previously unknown genetic polymorphism in malaria mosquitoes may be caused by a differential amplification of DNA repeats or an inversion in the sex chromosome heterochromatin.
Kinome Profiling of NF1-Related MPNSTs in Response to Kinase Inhibition and Doxorubicin Reveals Therapeutic Vulnerabilities
Authors: Grit Jamie L. , Pridgeon Matt G. , Essenburg Curt J. , Wolfrum Emily , Madaj Zachary B. , Turner Lisa , Wulfkuhle Julia , Petricoin Emanuel F. , Graveel Carrie R. , Steensma Matthew R.
Published: March 2020

Neurofibromatosis Type 1 (NF1)-related Malignant Peripheral Nerve Sheath Tumors (MPNST) are highly resistant sarcomas that account for significant mortality. The mechanisms of therapy resistance are not well-understood in MPNSTs, particularly with respect to kinase inhibition strategies. In this study, we aimed to quantify the impact of both the genomic context and targeted therapy on MPNST resistance using reverse phase phosphoproteome array (RPPA) analysis. We treated tumorgrafts from three genetically engineered mouse models using MET (capmatinib) and MEK (trametinib) inhibitors and doxorubicin, and assessed phosphosignaling at 4 h, 2 days, and 21 days. Baseline kinase signaling in our mouse models recapitulated an MET-addicted state (NF1-MET), P53 mutation (NF1-P53), and HGF overexpression (NF1). Following perturbation with the drug, we observed broad and redundant kinome adaptations that extended well beyond canonical RAS/ERK or PI3K/AKT/mTOR signaling. MET and MEK inhibition were both associated with an initial inflammatory response mediated by kinases in the JAK/STAT pathway and NFkB. Growth signaling predominated at the 2-day and 21-day time points as a result of broad RTK and intracellular kinase activation. Interestingly, AXL and NFkB were strongly activated at the 2-day and 21-day time points, and tightly correlated, regardless of the treatment type or genomic context. The degree of kinome adaptation observed in innately resistant tumors was significantly less than the surviving fractions of responsive tumors that exhibited a latency period before reinitiating growth. Lastly, doxorubicin resistance was associated with kinome adaptations that strongly favored growth and survival signaling. These observations confirm that MPNSTs are capable of profound signaling plasticity in the face of kinase inhibition or DNA damaging agent administration. It is possible that by targeting AXL or NFkB, therapy resistance can be mitigated.
Qualitative Field Observation of Pedestrian Injury Hotspots: A Mixed-Methods Approach for Developing Built- and Socioeconomic-Environmental Risk Signatures
Authors: Schuurman Nadine , Walker Blake Byron , Swanlund David , Amram Ofer , Yanchar Natalie L.
Published: March 2020

Road traffic injuries constitute a significant global health burden; the World Health Organization estimates that they result in 1.35 million deaths annually. While most pedestrian injury studies rely predominantly on statistical modelling, this paper argues for a mixed-methods approach combining spatial analysis, environmental scans, and local knowledge for assessing environmental risk factors. Using data from the Nova Scotia Trauma Registry, severe pedestrian injury cases and ten corresponding hotspots were mapped across the Halifax Regional Municipality. Using qualitative observation, quantitative environmental scans, and a socioeconomic deprivation index, we assessed hotspots over three years to identify key social- and built-environmental correlates. Injuries occurred in a range of settings; however, clear patterns were not observed based on land use, age, or socio-economic status (SES) alone. Three hotspots revealed an association between elevated pedestrian injury and a pattern of geographic, environmental, and socio-economic factors: low- to middle-SES housing separated from a roadside attraction by several lanes of traffic, and blind hills/bends. An additional generalized scenario was constructed representing common risk factors across all hotspots. This study is unique in that it moves beyond individual measures (e.g., statistical, environmental scans, or geographic information systems (GIS) mapping) to combine all three methods toward identifying environmental features associated with pedestrian motor vehicle crashes (PMVC).
Knowledge and Disposal Practice of Leftover and Expired Medicine: A Cross-Sectional Study from Nursing and Pharmacy Students’ Perspectives
Authors: Bashatah Adel , Wajid Syed
Published: March 2020

The objective of the present study was to investigate the knowledge and practices concerning unused and expired medicine among pharmacy and nursing students at King Saud University, Riyadh, Saudi Arabia. A cross-sectional study design was used. The study used a validated paper-based, self-administered questionnaire. Statistical analyses were performed using SPSS, Version 24. The response rate was 70.4% (n = 352). The results indicated that 57.4% of pharmacy students and 53.4% of nursing students check the expiry date of medicine before procuring, and 37.6% of pharmacy students and 52.5% of nursing students keep unused medicine until it expires. With regard to disposal, 78.9% of pharmacy students and 80.5% of nursing students reported discarding expired medicine in household garbage or flushing it down a sink or toilet. Only a small percentage returns leftover medicine to a medical store. There was a statistically significant difference between pharmacy and nursing students in regard to checking the expiry date of medicine before procuring (p = 0.01), and keeping unused medicine until it expires (p = 0.03). The study concluded that the majority of respondents dispose of medicine unsafely. The findings suggest that creating awareness regarding proper medicine disposal procedures among university health care students in Saudi Arabia is needed.
Do Polish Consumers Take Proper Care of Hygiene while Shopping and Preparing Meals at Home in the Context of Wasting Food?
Authors: Tomaszewska Marzena , Bilska Beata , Kołożyn-Krajewska Danuta
Published: March 2020

The objective of this paper is to evaluate the knowledge and practices of Polish consumers in terms of broadly defined hygiene on food preparation at home. The consequence of improper food handling may be a faster rate of food spoilage. A specially designed questionnaire was used. The study was conducted on a nationwide, random, and representative group of 1115 adult respondents. Segmentation (cluster analysis) of respondents differing in their practice and knowledge of meal preparation and personal hygiene was carried out. Several areas were diagnosed in which the respondents’ knowledge and practice were insufficient, such as storage of food products, inappropriate conduct of the thawing process, and heating of dishes. It was found that the best practice and knowledge of the issues discussed were characteristic of unemployed women over 35 years of age (cluster D). They offen gave answers that were significantly different (p < 0.05) from those given by the other clusters. The most limited knowledge and the worst practices were characteristic of mainly men with elementary and secondary education who are a part of the labor force (cluster E and A). The segmentation provided valuable information which indicates that educational programs on food safety need to be further strengthened.
Budgeting for Environmental Health Services in Healthcare Facilities: A Ten-Step Model for Planning and Costing
Authors: Anderson Darcy M. , Cronk Ryan , Best Lucy , Radin Mark , Schram Hayley , Tracy J. Wren , Bartram Jamie
Published: March 2020

Environmental health services (EHS) in healthcare facilities (HCFs) are critical for safe care provision, yet their availability in low- and middle-income countries is low. A poor understanding of costs hinders progress towards adequate provision. Methods are inconsistent and poorly documented in costing literature, suggesting opportunities to improve evidence. The goal of this research was to develop a model to guide budgeting for EHS in HCFs. Based on 47 studies selected through a systematic review, we identified discrete budgeting steps, developed codes to define each step, and ordered steps into a model. We identified good practices based on a review of additional selected guidelines for costing EHS and HCFs. Our model comprises ten steps in three phases: planning, data collection, and synthesis. Costing-stakeholders define the costing purpose, relevant EHS, and cost scope; assess the EHS delivery context; develop a costing plan; and identify data sources (planning). Stakeholders then execute their costing plan and evaluate the data quality (data collection). Finally, stakeholders calculate costs and disseminate findings (synthesis). We present three hypothetical costing examples and discuss good practices, including using costing frameworks, selecting appropriate indicators to measure the quantity and quality of EHS, and iterating planning and data collection to select appropriate costing approaches and identify data gaps.
Spatial Relationship between Natural Wetlands Changes and Associated Influencing Factors in Mainland China
Authors: Zhou Ting , Niu Anyi , Huang Zhanpeng , Ma Jiaojiao , Xu Songjun
Published: March 2020

Many studies have explored the dynamic change of wetlands distribution which play an important role in wetlands conservation and its sustainable management. However, given an uneven distribution of natural wetland resources in the context of global change, little is known about the spatial relationship between natural wetlands changes and associated influencing factors in mainland China. In this study, Moran-based spatial statistics are an effective methodology to examine the spatial patterns of natural wetlands and associated influencing factors at the province level, and GIS mapping is applied to help visualize spatial patterns. Results show that 1) significant spatial agglomeration and regional differences of natural wetlands distribution have been captured by Moran’s I statistics, and the agglomeration level has increased over the past ten years; 2) Seven of the eight factors show significantly strong and positive spatial autocorrelation except for water consumption, and spatial patterns of them show significant spatial clusters or spatial outliers; 3) Spatial coordination between natural wetlands distribution and the associated influencing factors is higher in the western region than in east China and northeast China. Moreover, spatial coordination between a cultivated area or water consumption and natural wetlands distribution is weaker than that of other factors. Finally, the influences generated by neighboring provinces should not be neglected in the implementation of wetlands conservation. This study could provide a scientific basis for the policy making of wetlands conservation and sustainable management systems.
Existence of Circulating Mitochondria in Human and Animal Peripheral Blood
Authors: Song Xiang , Hu Wei , Yu Haibo , Wang Honglan , Zhao Yelu , Korngold Robert , Zhao Yong
Published: March 2020

Mitochondria are usually located in the cytoplasm of cells where they generate adenosine triphosphate (ATP) to empower cellular functions. However, we found circulating mitochondria in human and animal blood. Electron microscopy confirmed the presence of mitochondria in adult human blood plasma. Flow cytometry analyses demonstrated that circulating mitochondria from the plasma of human cord blood and adult peripheral blood displayed the immune tolerance-associated membrane molecules such as CD270 and PD-L1 (programmed cell death-ligand 1). Similar data were obtained from fetal bovine serum (FBS) and horse serum of different vendors. Mitochondria remained detectable even after 56 °C heat inactivation. A real-time PCR array revealed purified mitochondria from animal sera expressed several genes that contribute to human T- and B-cell activation. Transwell experiments confirmed the migration capability of mitochondria through their expression of the chemokine receptor CXCR4 in responses to its ligand stromal-derived factor-1α (SDF-1α). Functional analysis established that human plasma mitochondria stimulated the proliferation of anti-CD3/CD28 bead-activated PBMC, up-regulated the percentage of activated CD4+ T and CD8+ T cells, and reduced the production of inflammatory cytokines. These findings suggested that the existence of circulating mitochondria in blood may function as a novel mediator for cell-cell communications and maintenance of homeostasis. Plasma-related products should be cautiously utilized in cell cultures due to the mitochondrial contamination.