bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic switching of Kerker scattering in spherical microresonators
Authors: Zouros Grigorios P. , Kolezas Georgios D. , Almpanis Evangelos , Baskourelos Konstantinos , Stefański Tomasz P. , Tsakmakidis Kosmas L. 
Published: July 2020

Abstract
Magneto-optical materials have become a key tool in functional nanophotonics, mainly due to their ability to offer active tuning between two different operational states in subwavelength structures. In the long-wavelength limit, such states may be considered as the directional forward- and back-scattering operations, due to the interplay between magnetic and electric dipolar modes, which act as equivalent Huygens sources. In this work, on the basis of full-wave electrodynamic calculations based on a rigorous volume integral equation (VIE) method, we demonstrate the feasibility of obtaining magnetically-tunable directionality inversion in spherical microresonators (THz antennas) coated by magneto-optical materials. In particular, our analysis reveals that when a high-index dielectric is coated with a magneto-optical material, we can switch the back-scattering of the whole particle to forward-scattering simply by turning off/on an external magnetic field bias. The validity of our calculations is confirmed by reproducing the above two-state operation, predicted by the VIE, with full-wave finite-element commercial software. Our results are of interest for the design of state-of-the-art active metasurfaces and metalenses, as well as for functional nanophotonic structures, and scattering and nanoantennas engineering.
Berberine/Ag nanoparticle embedded biomimetic calcium phosphate scaffolds for enhancing antibacterial function
Authors: Hu Cheng , Wu Lina , Zhou Changchun , Sun Huan , Gao Peng , Xu Xiujuan , Zhang Chenxi , Liang Jie , Fan Yujiang , Sun Jianxun , Zhou Xuedong , Zhang Xingdong 
Published: July 2020

Abstract
In the past decade, biomimetic calcium phosphate (CaP) ceramics have been considered as practicable grafts and biomaterial substitutes in repairing jaw bone defect after tumor resection or traffic accident. Nowadays, increasing incidence of biomedical material-associated infection has raised a concern when applying these materials. In this work, a new porous CaP scaffold with antibacterial coating was proposed. This biomimetic scaffold was composited with berberine (BBR), Ag nanoparticles (nAg), and silk fibroin (SF). The microstructures and phase composition of the scaffolds were analyzed. The cytocompatibility and osteogenic potential of the prepared samples were evaluated in vitro. The scaffolds held hierarchical structure: the first-level porous CaP ceramic with micron pores ranged from 250 to 600 µm; the second-level spongy-like structure with abundant capillary pores ranged from 500 nm to 10 µm; and the third-level structure was achieved by filling BBR, nAg, and SF gel coatings into the above porous structures. The experimental results showed that the antimicrobial capability of single BBR coating is inconspicuous. However, the introduction of nAg could significantly promote the antibacterial effect of scaffolds. At the same time, such scaffolds showed improved osteoinductivity. This new biomimetic CaP scaffold with antibacterial and osteoinductive properties may be a promising candidate for bone tissue engineering.
Corrosion behaviour of multilayer CrN coatings deposited by hybrid HIPIMS after oxidation treatment
Authors: Yu-Jie Zhu , Jing-Ling Ma , Guang-Xin Wang , Ke-Xing Song , Stock Heinz Rolf 
Published: July 2020

Abstract
Chromium nitride coatings prepared by physical vapour deposition (PVD) show high hardness, high strength and good thermal conductivity, which makes them useful for cutting and forming tools. In this article, the microstructure and corrosion resistance of multilayer Cr/CrN coatings deposited by arc evaporation and hybrid high power impulse magnetron sputtering (hybrid HIPIMS) after oxidation between 500 and 800°C were examined. The average thickness of the coatings was about 3.5 µm. By means of the surface morphology analysis, elemental energy spectrometry and potentiodynamic polarization tests, the performances of the two groups of coatings have been compared. The results revealed that the coating deposited by the hybrid HIPIMS has stronger binding force with substrate, fewer surface defects and a denser structure. Also, the hybrid HIPIMS coatings have a better oxidation resistance and a better corrosion resistance compared to the arc evaporated coatings.
Diversity and ecological characteristic of algae and cyanobacteria of thermokarst lakes in Yakutia (northeastern Russia)
Authors: Kopyrina Liubov , Pshennikova Elena , Barinova Sophia 
Published: July 2020

AbstractA total of 437 species (453 with infraspecific taxa) of algae and Cyanobacteria were identified in 2034 samples collected during the first research on nine thermokarst lakes in Yakutia carried out in 1986–1994 and 2001–2015. The richest algal flora was determined in Lake Aalah, represented by 241 taxa. Bacillariophyta species dominated in four lakes, whereas Chlorophyta and Cyanobacteria dominated in the others. The algal bioindication demonstrated preferences for benthic and plankticbenthic life, temperate temperature, low alkalinity, waters with moderate oxygenation, low to medium enrichment with chloride, low organic pollution, and mesotrophic state. Comparative floristic, CANOCO and JASP statistical methods divided the species and environmental variables into groups of lakes related to landscape terraces. Local landscape positions and high summer water temperatures may play a major role in the formation of algal flora. The index of algae taxa per area stabilized at about 70 species per km2. The highest polymorphism of algae floras, defined by the Subspecies/Species Index, was determined for the lakes of the Tungulunskaya terrace: Lake Ynakh, Lake Nal Tungulu and Lake Tungulu (1.041–1.058), and the average total flora was 1.036. Our results can help in monitoring and protecting the ecosystems of thermokarst lakes in Yakutia in the harsh climate environment of Northeastern Eurasia.
Hexabromocyclododecane contamination of herring gulls in the coastal area of the southern Baltic Sea
Authors: Reindl Andrzej , Falkowska Lucyna , Grajewska Agnieszka 
Published: July 2020

Abstract
Muscles and livers of herring gulls (Larus argentatus) found in the coastal area of the southern Baltic Sea were tested for the presence of hexabromocyclododecane (HBCD) isomers. They were detected in the muscles (ΣHBCD = 42.82 ± 30.65 ng g−1 l.w.) and livers (ΣHBCD = 65.51±27.96 ng g−1 l.w.) of all examined gulls. The α-HBCD isomer dominates in all types of samples. Our study has shown that bodies of gulls are less contaminated with HBCD than bodies of aquatic birds from other regions of the world. There was no clear correlation between HBCD concentrations and sex and age of birds. Nevertheless, it was indicated that the highest concentrations of HBCD and the α-HBCD isomer were found in the livers of immature females (mean = 89.31 ± 21.63 ng g−1 l.w. and mean = 76.72±24.54 ng g−1 l.w., respectively). The highest liver sequestration rates of the α-HBCD isomer were found in both adult and immature males (mean = 7.7 ± 13.7 and mean = 6.2 ± 11.9, respectively).
Plant replacement trend in soft-water lakes with isoetids
Authors: Ronowski Rafał P. , Banaś Krzysztof , Merdalski Marek , Szmeja Józef 
Published: July 2020

Abstract
A number of small, shallow inland lakes in the Northern Hemisphere are acidic, soft-water water bodies, mostly fed by precipitation. Some of these lakes are home to Lobelia dortmanna and other aquatic macrophytes from the isoetid group. The present study identifies a plant species replacement trend along the main environmental gradient in such lakes, i.e. pH of water.
In 70 lakes covered by the study and ordered along the gradient of increasing alkalinity, bryophytes gradually decline. Their decreasing frequency is 86.8% (pH 4.0), 32.5% (pH 6.5) and <10% (pH 6.6–9.5). At the same time, the frequency of vascular plants increases from 13.2% in strongly acidic lakes up to 92.8% in alkaline ones. The majority of isoetids usually occur at pH 5.5–6.7, but one of them (Littorella uniflora) often (frequency 40.5%) occurs also in eutrophic, alkaline lakes (pH 9.0–9.5), where it forms large populations. In lakes ranked according to the decreasing alkalinity gradient, bryophyte populations have been found to be smaller, while vascular plants become more abundant. The decreasing water acidity leads to partial or total elimination of bryophytes, which are replaced by eutrophilic vascular plants, frequently accompanied by some stonewort species.
Chemical Characterization of Vitreous Finds from Cosenza Cathedral (Calabria – Italy) by the Combined Use of Analytical Techniques
Authors: Barca Donatella , Papparella Franca C. 
Published: July 2020

AbstractThis article presents an archaeometrical research carried out on twenty-six vitreous finds collected in the Cosenza Cathedral (Calabria, Italy). The glasses have been subdivided in two typo-chronological groups. The first group is composed of 14 vitreous samples dating to the 4th–6th century AD. The second group includes twelve samples; seven are stems of funnel-shaped hanging lamps which date between the 12th and the 13th century AD, two are bottlenecks of balsamaria and three are concave bases. The aims of this study were the determination of the chemical composition of vitreous finds and the individuation of the primary glass sources. The samples were characterized through Electron Probe Micro Analyser with Wavelength Dispersive Spectrometer (EPMA-WDS) and Laser Ablation with Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The data confirm that all the finds of the first group are “silica-soda-lime” type glasses characterized by a high content of Na2O and a low content of K2O and MgO. On the contrary, the samples of the second group, showing higher contents of K2O and MgO, are vegetable silica-soda-lime glasses. Their composition confirms the typological attribution to the medieval period.
Ni–Mo sulfide nanosized catalysts from water-soluble precursors for hydrogenation of aromatics under water gas shift conditions
Authors: Vutolkina Anna , Glotov Aleksandr , Baygildin Ilnur , Akopyan Argam , Talanova Marta , Terenina Maria , Maximov Anton , Karakhanov Eduard 
Published: July 2020

Abstract
The unsupported catalysts were obtained during hydrogenation by in situ high-temperature decomposition (above 300 °C) of water-soluble metal precursors (ammonium molybdate and nickel nitrate) in water-in-oil (W/O) emulsions stabilized by surfactant (SPAN-80) using elemental sulfur as sulfiding agent. These self-assembly Ni–Mo sulfide nanosized catalysts were tested in hydrogenation of aromatics under CO pressure in water-containing media for hydrogen generation through a water gas shift reaction (WGSR). The composition of the catalysts was determined by XRF and active sulfide phase was revealed by XRD, TEM and XPS techniques. The calculations based on TEM and XPS data showed that the catalysts are highly dispersed. The surfactant was found to affect both dispersion and metal distribution for Ni and Mo species, providing shorter slab length in terms of sulfide particle formation and stacking within high content of NiMoS phase. Catalytic evaluation in hydrogenation of aromatics was performed in a high-pressure batch reactor at T = 380–420 °С, p(CO) = 5 MPa with water content of 20 wt.% and CO/H2O molar ratio of 1.8 for 4–8 h. As shown experimentally with unsupported Ni–Mo sulfide catalysts, the activity of aromatic rings depends on the substituent therein and decreases as follows: anthracene>>1-methylnaphthalene≈2-methylnaphthalene>1,8-dimethylnaphthale-ne>>1,3-di-methylnaphthalene>2,6-dimethylnaphthalene≈2,3-dimethylnaphthalene>2-ethyl-naphthalene. The anthracene conversion reaches up to 97–100% for 4 h over the whole temperature range, while for 1MN and 2MN it doesn’t exceed 92 and 86% respectively even at 420 °С for 8 h. Among dimethyl-substituted aromatics the higher conversion of 45% was achieved for 1,8-dimethylnaphthalene with 100% selectivity to tetralines at 400 °С for 6 h. Similar to 1- and 2-methylnaphtalenes, the hydrogenation of asymmetric dimethyl-substituted substrate carries out through the unsubstituted aromatic ring indicating that steric factors influence on the sorption mechanism over active metal sites. The catalysts were found to be reused for at least six cycles when the hydrogenation is sulfur-assisted preventing metal oxide formation. It was established, that at the first 2–3 h known as the induction period, the oxide catalyst precursors formed slowly by metal salt decomposition, which reveals that it is the rate-determining step. The sulfidation is rather fast based on high catalytic activity data on 2MN conversion retaining at 93–95% upon recycling.
Unusual behavior of bimetallic nanoparticles in catalytic processes of hydrogenation and selective oxidation
Authors: Redina Elena A. , Kirichenko Olga A. , Shesterkina Anastasiya A. , Kustov Leonid M. 
Published: July 2020

Abstract
Recent results obtained in studying mono- and bimetallic catalysts for selective hydrogenation of unsaturated carbonyl compounds, even unsaturated ones, acetylenic and nitro compounds as well as CO and bio-available alcohols oxidation are reviewed from the standpoint of the strong interaction between the metal nanoparticles, on the one hand, and two metals in the composition of bimetallic nanoparticles, on the other hand. Such interactions were demonstrated to result in partial positive or negative charging of metal nanoparticles, which, in turn, changes their adsorption and catalytic properties, especially with respect to the reactions involving hydrogen. Among the systems studied, Au–Pt, Au–Pd, Au–Cu, Au–Fe, Pt–WO
x
, Fe–Pd, Fe–Pt, Fe–Cu nanoparticles prepared by the redox procedure are considered to be most perspective in diverse catalytic applications because of the proper combination of the particle size and the electronic state of the metals.
COVID-19 and Collective Action
Authors: Sandler Todd 
Published: July 2020

Abstract
This conceptual article argues that COVID-19 poses myriad global collective action challenges, some of which are easier than others to address. COVID-19 requires numerous distinct activities – e.g., vaccine development, uncovering treatment practices, imposing quarantines, and disease surveillance. The prognosis for effective collective action rests on the underlying aggregator technologies, which indicate how individual contributions determine the amount of a COVID-19 activity that is available for consumption. Best- and better-shot aggregators are more apt to promote desired outcomes than weakest- and weaker-link aggregators. The roles for public policy and important actors (e.g., multi-stakeholder partnerships) in fostering collective action are indicated.
Capitalism and COVID-19: Crisis at the Crossroads
Authors: Murshed Syed Mansoob 
Published: July 2020

AbstractExistential threats, such as the COVID-19 pandemic, have historically engendered intellectual paradigm shifts, and even systemic transformations in the economy and polity. This paper focuses on two inter-related phenomena: rising economic inequality and the diminution of liberal democracy, a feature common to both developed and developing countries set in the context of a ubiquitous and globalized capitalism. In the post-pandemic world, we need to harness the positive dimensions of the powerful capitalist system to lower inequality and build a newer world akin to an earlier golden age of capitalism.
Continuous reactors of frontal polymerization in flow for the synthesis of polyacrylamide hydrogels with prescribed properties
Authors: Tonoyan Anahit O. , Varderesyan Anahit Z. , Ketyan Armine G. , Minasyan Aram H. , Hovnanyan Karlen O. , Davtyan Sevan P. 
Published: July 2020

Abstract
Taking into account the fact that since the 1970s frontal polymerization (FP) reactors in flow have been the subject of our study, the work gives a brief chronology of the development of FP reactors for the synthesis of high molecular polymers, polymeric hydrogels with cross-linked structure, their advantages and drawbacks. The reasons for the impossibility of the practical implementation of tubular FP reactors in flow for the synthesis of polymers are established. The possibility of implementation of tubular FP reactors for the synthesis of polyacrylamide hydrogels (PAH) capable of absorbing and releasing large amount of water is presented. The paper also presents some data on the methods for the synthesis of PAHs with prescribed properties in tubular continuous FP reactors by way of using nano-additives and regulating the kinetics of the synthesis process. As a result, the synthesis process of PAHs with the required properties both in the absorption and release of water, and in the physical-mechanical properties was carried out in frontal tubular-type reactors in flow, and the water absorption kinetic curves and physical-mechanical properties of the obtained hydrogels are presented.
Sonochemically synthetized ZnO-Graphene nanohybrids and its characterization
Authors: Cobianu Cornel , Dumbravescu Niculae , Serban Bogdan-Catalin , Buiu Octavian , Romanitan Cosmin , Comanescu Florin , Danila Mihai , Marinescu Roxana , Avramescu Viorel , Ionescu Octavian 
Published: July 2020

AbstractThe paper presents the morphological, structural and compositional properties of the sonochemically prepared ZnO-1.4wt% Graphene (Z-G) nanocomposites as a function of pH value of suspension varying from 8.5 to 14 and thermal annealing at 450°C in nitrogen or air ambient. The SEM analysis of the Z-G hybrids dried at 150°C in air has shown a nano-flower like nanostructure for a pH value of 14. The XRD analysis of dried Z-G hybrids revealed a crystallite size increase from 3.5 nm to 18.4 nm with pH increase, and this result was explained in terms of colloids zeta potential evolution with pH value. The Raman and EDS spectroscopy have shown a split of the G band (1575 cm−1) of graphene into two bands (1575 cm−1and 1605 cm−1), an increased height of D (1323 cm−1) band, and an additional amount of carbon due to CO2absorption from the air, respectively. The carbon incorporation increased with the decrease of pH, and was associated with a hydrozincite phase, Zn5(CO3)2(OH)6. The formation of dried Z-G nanocomposite was clearly demonstrated only at a pH value equal to 14, where two ZnO Raman active bands at 314.9 cm−1and 428.2 cm−1appeared. This result may indicate the sensitivity of the Raman spectroscopy to the nanoflower-like nanostructure of dried Z-G hybrids prepared at pH=14.The thermal treatment of Z-G hybrids in N2at 450°Chas increased the number of ZnO Raman bands as a function of pH value, it has decreased the amount of additional carbon by conversion of hydrozincite to ZnO andpreserved the graphene profile.The thermal treatment in air at 450°Chas increased the crystalline symmetry and stoichiometry of the ZnO as revealed by high and narrow Raman band from 99 cm−1specific to Zn optical phonons, but ithas severely affected the graphene profile in the Z-G hybrid, due to combustion of graphene in oxygen from the ambient.
Crystal structures of perovskite halide compounds used for solar cells
Authors: Oku Takeo 
Published: July 2020

AbstractThe crystal structures of various types of perovskite halide compounds were summarized and described. Atomic arrangements of these perovskite compounds can be investigated by X-ray diffraction and transmission electron microscopy. Based on the structural models of basic perovskite halides, X-ray and electron diffractions were calculated and discussed to compare with the experimental data. Other halides such as elemental substituted or cation ordered double perovskite compounds were also described. In addition to the ordinary 3-dimensional perovskites, low dimensional perovskites with 2-, 1-, or 0-dimensionalities were summarized. The structural stabilities of the perovskite halides could be investigated computing the tolerance and octahedral factors, which can be useful for the guideline of elemental substitution to improve the structures and properties, and several low toxic halides were proposed. For the device conformation, highly crystalline-orientated grains and dendritic structures can be formed and affected the photo-voltaic properties. The actual crystal structures of perovskite halides in the thin film configuration were studied by Rietveld analysis optimizing the atomic coordinates and occupancies with low residual factors. These results are useful for structure analysis of perovskite halide crystals, which are expected to be next-generation solar cell materials.
Risk of Mercury exposure during childhood: a review of Sri Lankan situation
Authors: Galappaththi Himan K. A. , Suraweera Inoka 
Published: July 2020

AbstractSri Lanka had ratified the Minamata convention in the year 2017 and is planning to phase out Mercury by 2020. Mercury thermometers and compact fluorescent light bulbs are abundant at hospitals, households and schools. Limitations in safe disposal and containment mechanisms have enhanced the unregulated e-waste collection and extraction. Sri Lanka has plentiful lagoons, fishing bays, and inland irrigation systems. Fish consumption is high, especially around the coastal belt. Mercury can bioaccumulate in humans by the consumption of fish from contaminated sources. Children are at risk of exposure in their living environments and via food. A multicountry study done across three oceans on Mercury threat to women & children revealed, lagoon pollution from industrial Mercury emissions in Sri Lanka, possessing high Mercury among local females who consume fish from that lagoon. The mean hair Mercury level in coastal areas with high fish consumption exceeded the reference dose even among children. Aquatic life and crop studies revealed a mixed picture of Mercury levels which some are lower and some are higher than the permissible levels. Studies on environmental Mercury levels and correlations with health effects among children will help to fill the data gap. Public awareness of the health effects of Mercury and mechanisms of Mercury disposal should be established.
MAV quaternion attitude determination for accelerometer-magnetometer combination: Internal analysis
Authors: Wu Jin , Zhang Chengxi , Zhou Zebo 
Published: July 2020

AbstractThis paper proposes a novel fast deterministic quaternion attitude determination method for accelerometer and magnetometer combination (AMC). After taking insight to the attitude determination theory, an important relationship between the sensor outputs and the magnetometer’s reference vector is successfully derived. Based on the relationship, the optimal quaternion associated with the attitude of a certain object is easily calculated. The main breakthrough of this paper is that it significantly simplifies the determination of the magnetometer’s reference vector which always needs systematic calibration or iterative estimation in existing methods. We name the proposed method the Fast Accelerometer-Magnetometer Fusion (FAMF). Our proposed method has the advantages of better computation accuracy and less time consumption. Several experiments are carried out to illustrate the attitude determination results. Besides, comparisons with existing representative methods are also presented in the experimental section of this paper, which verify the effectiveness of the proposed FAMF. Finally, we experimentally show that the FAMF’s roll and pitch angles are immune to magnetic distortion, which ensures the robustness under complex environments for micro air vehicles (MAV).