bluuebunny/crossref_metadata_2025 huggingface dataset:
On Inverses of the Dirac Comb
Authors: Fischer Jens V. , Stens Rudolf L.
Published: December 2019

We determine tempered distributions which convolved with a Dirac comb yield unity and tempered distributions, which multiplied with a Dirac comb, yield a Dirac delta. Solutions of these equations have numerous applications. They allow the reversal of discretizations and periodizations applied to tempered distributions. One of the difficulties is the fact that Dirac combs cannot be multiplied or convolved with arbitrary functions or distributions. We use a theorem of Laurent Schwartz to overcome this difficulty and variants of Lighthill’s unitary functions to solve these equations. The theorem we prove states that double-sided (time/frequency) smooth partitions of unity are required to neutralize discretizations and periodizations on tempered distributions.
Influence of Na2CO3 and K2CO3 Addition on Iron Grain Growth during Carbothermic Reduction of Red Mud
Authors: Zinoveev Dmitry , Grudinsky Pavel , Zakunov Andrey , Semenov Artem , Panova Maria , Valeev Dmitry , Kondratiev Alex , Dyubanov Valery , Petelin Alexander
Published: December 2019

Red mud is a by-product of alumina production from bauxite ore by the Bayer method, which contains considerable amounts of valuable components such as iron, aluminum, titanium, and scandium. In this study, an approach was applied to extract iron, i.e., carbothermic reduction roasting of red mud with sodium and potassium carbonates followed by magnetic separation. The thermodynamic analysis of iron and iron-free components’ behavior during carbothermic reduction was carried out by HSC Chemistry 9.98 (Outotec, Pori, Finland) and FactSage 7.1 (Thermfact, Montreal, Canada; GTT-Technologies, Herzogenrath, Germany) software. The effects of the alkaline carbonates’ addition, as well as duration and temperature of roasting on the iron metallization degree, iron grains’ size, and magnetic separation process were investigated experimentally. The best conditions for the reduction roasting were found to be as follows: 22.01% of K2CO3 addition, 1250 °C, and 180 min of duration. As a generalization of the obtained data, the mechanism of alkaline carbonates’ influence on iron grain growth was proposed.
Development of Experimental Chamber for Testing High-Temperature Hydrogen Permeation through Metal Foils
Authors: Kudiiarov Viktor , Sakvin Ivan , Garanin Georgy , Lider Andrey
Published: December 2019

This paper describes the methodology for conducting experiments to study hydrogen diffusion through metal membranes using a specially designed diffusion chamber of an automated gas reaction controller complex. This complex allows experiments to study hydrogen diffusion with the following parameters: the inlet hydrogen pressure is up to 50 atmospheres, and the temperature in the chamber is from 30 °C to 1000 °C. The size of the samples is limited to a diameter of 10 mm and a thickness of 100 μm. The method for calculating the diffusion coefficient based on the Fick equation is also described. When studying hydrogen diffusion through a sample of Zr–1Nb alloy with nickel film deposited at the temperature of 550 °C, it was noted that phase transformations can be observed on the diffusion curve.
Leaching Manganese Nodules in an Acid Medium and Room Temperature Comparing the Use of Different Fe Reducing Agents
Authors: Torres David , Ayala Luís , Saldaña Manuel , Cánovas Manuel , Jeldres Ricardo I. , Nieto Steven , Castillo Jonathan , Robles Pedro , Toro Norman
Published: December 2019

The deposits of Fe-Mn, in the seabed of the planet, are a good alternative source for the extraction of elements of interest. Among these are marine nodules, which have approximately 24% manganese and may be a solution to the shortage of high-grade ores on the surface. In this investigation, an ANOVA analysis was performed to evaluate the time independent variables and MnO2/reducing agent in the leaching of manganese nodules with the use of different Fe reducing agents (FeS2, Fe2+, Fe0 and Fe2O3). Tests were also carried out for the different reducing agents evaluating the MnO2/Fe ratio, in which the Fe0 (FeC) proved to be the best reducing agent for the dissolution of Mn from marine nodules, achieving solutions of 97% in 20 min. In addition, it was discovered that at low MnO2/Fe ratios the acid concentration in the system is not very relevant and the potential and pH were in ranges of −0.4–1.4 V and −2–0.1 favoring the dissolution of Mn from MnO2.
Alloying Element Segregation and Grain Boundary Reconstruction, Atomistic Modeling
Authors: Karkina Lidia , Karkin Iliya , Kuznetsov Andrey , Gornostyrev Yuri
Published: December 2019

Grain boundary (GB) segregation is an important phenomenon that affects many physical properties, as well as microstructure of polycrystals. The segregation of solute atoms on GBs and its effect on GB structure in Al were investigated using two approaches: First principles total energy calculations and the finite temperature large-scale atomistic modeling within hybrid MD/MC approach comprising molecular dynamics and Monte Carlo simulations. We show that the character of chemical bonding is essential in the solute–GB interaction, and that formation of directed quasi-covalent bonds between Si and Zn solutes and neighboring Al atoms causes a significant reconstruction of the GB structure involving a GB shear-migration coupling. For the solutes that are acceptors of electrons in the Al matrix and have a bigger atomic size (such as Mg), the preferred position is determined by the presence of extra volume at the GB and/or reduced number of the nearest neighbors; in this case, the symmetric GB keeps its structure. By using MD/MC approach, we found that GBs undergo significant structural reconstruction during segregation, which can involve the formation of single- or double-layer segregations, GB splitting, and coupled shear-migration, depending on the details of interatomic interactions.
Vertical Field Emission Air-Channel Diodes and Transistors
Authors: Chang Wen-Teng , Hsu Hsu-Jung , Pao Po-Heng
Published: December 2019

Vacuum channel transistors are potential candidates for low-loss and high-speed electronic devices beyond complementary metal-oxide-semiconductors (CMOS). When the nanoscale transport distance is smaller than the mean free path (MFP) in atmospheric pressure, a transistor can work in air owing to the immunity of carrier collision. The nature of a vacuum channel allows devices to function in a high-temperature radiation environment. This research intended to investigate gate location in a vertical vacuum channel transistor. The influence of scattering under different ambient pressure levels was evaluated using a transport distance of about 60 nm, around the range of MFP in air. The finite element model suggests that gate electrodes should be near emitters in vertical vacuum channel transistors because the electrodes exhibit high-drive currents and low-subthreshold swings. The particle trajectory model indicates that collected electron flow (electric current) performs like a typical metal oxide semiconductor field effect-transistor (MOSFET), and that gate voltage plays a role in enhancing emission electrons. The results of the measurement on vertical diodes show that current and voltage under reduced pressure and filled with CO2 are different from those under atmospheric pressure. This result implies that this design can be used for gas and pressure sensing.
Synthesis and Anti-Proliferative Assessment of Triazolo-Thiadiazepine and Triazolo-Thiadiazine Scaffolds
Authors: Boraei Ahmed T. A. , Ghabbour Hazem A. , Gomaa Mohamed S. , El Ashry El Sayed H. , Barakat Assem
Published: December 2019

A series of triazolo-thiadiazepines 4a–k were synthesized with excellent yields using dehydrated PTSA as a catalyst in toluene. Two triazolo-thiadiazines were obtained; 8a was formed directly by reflux in ethanol, whereas, PTSA promoted the formation of 8b. The molecular structure of the formed triazolo-thiadiazepines is identical to the imine-form 4a–k and not the enamine-tautomer 6a–k. The structures of the newly synthesized triazolo-thiadiazepines 4a–k and triazolo-thiadiazines 8a–b were elucidated using NMR (1H, and 13C), 2D NMR, HRMS, and X-ray single crystal. Furthermore, 4a was deduced using X-ray single crystal diffraction analysis. These new thiadiazepine hits represent an optimized series of previously synthesized indole-triazole derivatives for the inhibition of EGFR. The cytotoxicity activity against two cancer cell lines including human liver cancer (HEPG-2) and breast cancer (MCF-7) was promising, with IC50 between 12.9 to 44.6 µg/mL and 14.7 to 48.7 µg/mL for the tested cancer cell lines respectively, compared to doxorubicin (IC50 4.0 µg/mL). Docking studies revealed that the thiadiazepine scaffold presented a suitable anchor, allowing good interaction of the various binding groups with the enzyme binding regions and sub-pockets.
Investigating the Binding Mode of Reversible LSD1 Inhibitors Derived from Stilbene Derivatives by 3D-QSAR, Molecular Docking, and Molecular Dynamics Simulation
Authors: Xu Yongtao , He Zihao , Yang Min , Gao Yunlong , Jin Linfeng , Wang Meiting , Zheng Yichao , Lu Xiaoyuan , Zhang Songjie , Wang Chang , Zhao Zongya , Zhao Junqiang , Gao Qinghe , Duan Yingchao
Published: December 2019

Overexpression of lysine specific demethylase 1 (LSD1) has been found in many cancers. New anticancer drugs targeting LSD1 have been designed. The research on irreversible LSD1 inhibitors has entered the clinical stage, while the research on reversible LSD1 inhibitors has progressed slowly so far. In this study, 41 stilbene derivatives were studied as reversible inhibitors by three-dimensional quantitative structure–activity relationship (3D-QSAR). Comparative molecular field analysis (CoMFA q 2 = 0.623, r 2 = 0.987, r pred 2 = 0.857) and comparative molecular similarity indices analysis (CoMSIA q 2 = 0.728, r 2 = 0.960, r pred 2 = 0.899) were used to establish the model, and the structure–activity relationship of the compounds was explained by the contour maps. The binding site was predicted by two different kinds of software, and the binding modes of the compounds were further explored. A series of key amino acids Val288, Ser289, Gly314, Thr624, Lys661 were found to play a key role in the activity of the compounds. Molecular dynamics (MD) simulations were carried out for compounds 04, 17, 21, and 35, which had different activities. The reasons for the activity differences were explained by the interaction between compounds and LSD1. The binding free energy was calculated by molecular mechanics generalized Born surface area (MM/GBSA). We hope that this research will provide valuable information for the design of new reversible LSD1 inhibitors in the future.
Photocatalytic Difluoromethylation Reactions of Aromatic Compounds and Aliphatic Multiple C–C Bonds
Authors: Barata-Vallejo Sebastián , Postigo Al
Published: December 2019

Among the realm of visible light photocatalytic transformations, late-stage difluoromethylation reactions (introduction of difluoromethyl groups in the last stages of synthetic protocols) have played relevant roles as the CF2X group substitutions exert positive impacts on the physical properties of organic compounds including solubility, metabolic stability, and lipophilicity, which are tenets of considerable importance in pharmaceutical, agrochemical, and materials science. Visible-light-photocatalyzed difluoromethylation reactions are shown to be accomplished on (hetero)aromatic and carbon–carbon unsaturated aliphatic substrates under mild and environmentally benign conditions.
Chiral Chalcogen Bond Donors Based on the 4,4′-Bipyridine Scaffold
Authors: Weiss Robin , Aubert Emmanuel , Peluso Paola , Cossu Sergio , Pale Patrick , Mamane Victor
Published: December 2019

Organocatalysis through chalcogen bonding (ChB) is in its infancy, as its proof-of-principle was only reported in 2016. Herein, we report the design and synthesis of new chiral ChB donors, as well as the catalytic activity evaluation of the 5,5′-dibromo-2,2′-dichloro-3-((perfluorophenyl)selanyl)-4,4′-bipyridine as organocatalyst. The latter is based on the use of two electron-withdrawing groups, a pentafluorophenyl ring and a tetrahalo-4,4′-bipyridine skeleton, as substituents at the selenium center. Atropisomery of the tetrahalo-4,4′-bipyridine motif provides a chiral environment to these new ChB donors. Their synthesis was achieved through either selective lithium exchange and trapping or a site-selective copper-mediated reaction. Pure enantiomers of the 3-selanyl-4,4′-bipyridine were obtained by high performance liquid chromatography enantioseparation on specific chiral stationary phase, and their absolute configuration was assigned by comparison of the measured and calculated electronic circular dichroism spectra. The capability of the selenium compound to participate in σ-hole-based interactions in solution was studied by 19F NMR. Even if no asymmetric induction has been observed so far, the new selenium motif proved to be catalytically active in the reduction of 2-phenylquinoline by Hantzsch ester.
A Skin-Inspired Stretchable, Self-Healing and Electro-Conductive Hydrogel with a Synergistic Triple Network for Wearable Strain Sensors Applied in Human-Motion Detection
Authors: Chen Yuanyuan , Lu Kaiyue , Song Yuhan , Han Jingquan , Yue Yiying , Biswas Subir Kumar , Wu Qinglin , Xiao Huining
Published: December 2019

Hydrogel-based strain sensors inspired by nature have attracted tremendous attention for their promising applications in advanced wearable electronics. Nevertheless, achieving a skin-like stretchable conductive hydrogel with synergistic characteristics, such as ideal stretchability, excellent sensing performance and high self-healing efficiency, remains challenging. Herein, a highly stretchable, self-healing and electro-conductive hydrogel with a hierarchically triple-network structure was developed through a facile two-step preparation process. Firstly, 2, 2, 6, 6-tetrametylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils were homogeneously dispersed into polyacrylic acid hydrogel, with the presence of ferric ions as an ionic crosslinker to synthesize TEMPO-oxidized cellulose nanofibrils/polyacrylic acid hydrogel via a one-pot free radical polymerization. A polypyrrole conductive network was then incorporated into the synthetic hydrogel matrix as the third-level gel network by polymerizing pyrrole monomers. The hierarchical 3D network was mutually interlocked through hydrogen bonds, ionic coordination interactions and physical entanglements of polymer chains to achieve the target composite hydrogels with a homogeneous texture, enhanced mechanical stretchability (elongation at break of ~890%), high viscoelasticity (maximum storage modulus of ~27.1 kPa), intrinsic self-healing ability (electrical and mechanical healing efficiencies of ~99.4% and 98.3%) and ideal electro-conductibility (~3.9 S m−1). The strain sensor assembled by the hybrid hydrogel, with a desired gauge factor of ~7.3, exhibits a sensitive, fast and stable current response for monitoring small/large-scale human movements in real-time, demonstrating promising applications in damage-free wearable electronics.
CO2 Hydrogenation over Nanoceria-Supported Transition Metal Catalysts: Role of Ceria Morphology (Nanorods versus Nanocubes) and Active Phase Nature (Co versus Cu)
Authors: Konsolakis Michalis , Lykaki Maria , Stefa Sofia , Carabineiro Sόnia A. C. , Varvoutis Georgios , Papista Eleni , Marnellos Georgios E.
Published: December 2019

In this work we report on the combined impact of active phase nature (M: Co or Cu) and ceria nanoparticles support morphology (nanorods (NR) or nanocubes (NC)) on the physicochemical characteristics and CO2 hydrogenation performance of M/CeO2 composites at atmospheric pressure. It was found that CO2 conversion followed the order: Co/CeO2 > Cu/CeO2 > CeO2, independently of the support morphology. Co/CeO2 catalysts demonstrated the highest CO2 conversion (92% at 450 °C), accompanied by 93% CH4 selectivity. On the other hand, Cu/CeO2 samples were very selective for CO production, exhibiting 52% CO2 conversion and 95% CO selectivity at 380 °C. The results obtained in a wide range of H2:CO2 ratios (1–9) and temperatures (200–500 °C) are reaching in both cases the corresponding thermodynamic equilibrium conversions, revealing the superiority of Co- and Cu-based samples in methanation and reverse water-gas shift (rWGS) reactions, respectively. Moreover, samples supported on ceria nanocubes exhibited higher specific activity (µmol CO2·m−2·s−1) compared to samples of rod-like shape, disclosing the significant role of support morphology, besides that of metal nature (Co or Cu). Results are interpreted on the basis of different textural and redox properties of as-prepared samples in conjunction to the different impact of metal entity (Co or Cu) on CO2 hydrogenation process.
Covalent Bonding of Si Nanoparticles on Graphite Nanosheets as Anodes for Lithium-Ion Batteries Using Diazonium Chemistry
Authors: Zhang Yi , Ren Jinghui , Xu Tao , Feng Ailing , Hu Kai , Yu Nengfei , Xia Yingbin , Zhu Yusong , Huang Zhengyong , Wu Guanglei
Published: December 2019

Silicon/carbon (Si/C) composite has been proven to be an effective method of enhancing the electrochemical performance of Si-based anodes for lithium-ion batteries (LIBs). However, the practical application of Si/C materials in LIBs is difficult because of the weak interaction between Si and C. In this study, we applied two-step diazotization reactions to modify graphite nanosheets (GNs) and Si nanoparticles (Si NPs), yielding a stable Si–Ar–GNs composite. Owing to aryl (Ar) group bonding, Si NPs were dispersed well on the GNs. The as-prepared Si–Ar–GNs composite delivered an initial reversible capacity of 1174.7 mAh·g−1 at a current density of 100 mAh·g−1. Moreover, capacity remained at 727.3 mAh·g−1 after 100 cycles, showing improved cycling performance. This synthesis strategy can be extended to prepare other Si/C anode materials of LIBs.
Mechanistic Understanding of Curcumin’s Therapeutic Effects in Lung Cancer
Authors: Wan Mohd Tajuddin Wan Nur Baitty , Lajis Nordin H. , Abas Faridah , Othman Iekhsan , Naidu Rakesh
Published: December 2019

Lung cancer is among the most common cancers with a high mortality rate worldwide. Despite the significant advances in diagnostic and therapeutic approaches, lung cancer prognoses and survival rates remain poor due to late diagnosis, drug resistance, and adverse effects. Therefore, new intervention therapies, such as the use of natural compounds with decreased toxicities, have been considered in lung cancer therapy. Curcumin, a natural occurring polyphenol derived from turmeric (Curcuma longa) has been studied extensively in recent years for its therapeutic effects. It has been shown that curcumin demonstrates anti-cancer effects in lung cancer through various mechanisms, including inhibition of cell proliferation, invasion, and metastasis, induction of apoptosis, epigenetic alterations, and regulation of microRNA expression. Several in vitro and in vivo studies have shown that these mechanisms are modulated by multiple molecular targets such as STAT3, EGFR, FOXO3a, TGF-β, eIF2α, COX-2, Bcl-2, PI3KAkt/mTOR, ROS, Fas/FasL, Cdc42, E-cadherin, MMPs, and adiponectin. In addition, limitations, strategies to overcome curcumin bioavailability, and potential side effects as well as clinical trials were also reviewed.
Biomarkers of Whole-Grain and Cereal-Fiber Intake in Human Studies: A Systematic Review of the Available Evidence and Perspectives
Authors: Jawhara Mohamad , Sørensen Signe Bek , Heitmann Berit Lilienthal , Andersen Vibeke
Published: December 2019

High whole-grain consumption is related to better health outcomes. The specific physiological effect of these compounds is still unrevealed, partly because the accurate estimation of the intake of whole grains from dietary assessments is difficult and prone to bias, due to the complexity of the estimation of the intake by the consumer. A biomarker of whole-grain intake and type of whole-grain intake would be useful for quantifying the exposure to whole-grain intake. In this review, we aim to review the evidence on the potential biomarkers for whole-grain intake in the literature. We conducted a systematic search in Medline, Embase, Web of Science, and the Cochrane database. In total, 39 papers met the inclusion criteria following the PRISMA guidelines and were included. The relative validity, responsiveness, and reproducibility of these markers were assessed for short-, medium-, and long-term exposure as important criteria for the potential use of these biomarkers from a clinical and research perspective. We found three major groups of biomarkers: (1) alkylresorcinol, as well as its homologs and metabolites, assessed in plasma, adipose tissue biopsies, erythrocyte membranes, and urine; (2) avenacosides, assessed in urine samples; and (3) benzoxazinoid-derived phenylacetamide sulfates, assessed in blood and urine samples. The reviewed biomarkers may be used for improved assessment of associations between whole-grain intake and health outcomes.
Vitamin C Inhibits Triple-Negative Breast Cancer Metastasis by Affecting the Expression of YAP1 and Synaptopodin 2
Authors: Gan Liping , Camarena Vladimir , Mustafi Sushmita , Wang Gaofeng
Published: December 2019

Vitamin C supplementation has been shown to decrease triple-negative breast cancer (TNBC) metastasis. However, the molecular mechanism whereby vitamin C inhibits metastasis remains elusive. It has been postulated that vitamin C reduces the levels of HIF-1α, the master regulator of metastasis, by promoting its hydroxylation and degradation. Here, we show that vitamin C at 100 µM, a concentration achievable in the plasma in vivo by oral administration, blocks TNBC cell migration and invasion in vitro. The protein level of HIF-1α remains largely unchanged in cultured TNBC cells and xenografts, partially due to its upregulated transcription by vitamin C, suggesting that HIF-1α unlikely mediates the action of vitamin C on metastasis. Vitamin C treatment upregulates the expression of synaptopodin 2 and downregulates the expression of the transcription coactivator YAP1, both genes in the Hippo pathway. The changes in SYNPO2 and YAP1 expression were subsequently validated at mRNA and protein levels in cultured TNBC cells and xenografts. Further experiments showed that vitamin C treatment inhibits F-actin assembly and lamellipodia formation, which correlates with the changes in SYNPO2 and YAP1 expression. Overall, these results suggest that vitamin C inhibits TNBC metastasis by affecting the expression of SYNPO2 and YAP1. Vitamin C may thus have a potential role in the prevention and treatment of TNBC metastasis.
Monitoring the Fate of Orally Administered PLGA Nanoformulation for Local Delivery of Therapeutic Drugs
Authors: Morelli Lucia , Gimondi Sara , Sevieri Marta , Salvioni Lucia , Guizzetti Maria , Colzani Barbara , Palugan Luca , Foppoli Anastasia , Talamini Laura , Morosi Lavinia , Zucchetti Massimo , Violatto Martina Bruna , Russo Luca , Salmona Mario , Prosperi Davide , Colombo Miriam , Bigini Paolo
Published: December 2019

One of the goals of the pharmaceutical sciences is the amelioration of targeted drug delivery. In this context, nanocarrier-dependent transportation represents an ideal method for confronting a broad range of human disorders. In this study, we investigated the possibility of improving the selective release of the anti-cancer drug paclitaxel (PTX) in the gastro-intestinal tract by encapsulating it into the biodegradable nanoparticles made by FDA-approved poly(lactic-co-glycolic acid) (PLGA) and coated with polyethylene glycol to improve their stability (PLGA-PEG-NPs). Our study was performed by combining the synthesis and characterization of the nanodrug with in vivo studies of pharmacokinetics after oral administration in mice. Moreover, fluorescent PLGA-nanoparticles (NPs), were tested both in vitro and in vivo to observe their fate and biodistribution. Our study demonstrated that PLGA-NPs: (1) are stable in the gastric tract; (2) can easily penetrate inside carcinoma colon 2 (CaCo2) cells; (3) reduce the PTX absorption from the gastrointestinal tract, further limiting systemic exposure; (4) enable PTX local targeting. At present, the oral administration of biodegradable nanocarriers is limited because of stomach degradation and the sink effect played by the duodenum. Our findings, however, exhibit promising evidence towards our overcoming these limitations for a more specific and safer strategy against gastrointestinal disorders.
Hunting for Dwarf Galaxies Hosting the Formation and Coalescence of Compact Binaries
Authors: Graziani Luca
Published: December 2019

Here we introduce the latest version of the GAMESH model, capable to consistently account for the formation and evolution of compact binary systems along the cosmic assembly of a Milky Way (MW)-like galaxy, centered on a local group volume resolving a large population of dwarf satellites. After describing the galaxy assembly process and how the formation of binary systems is accounted for, we summarize some recent findings on the properties and evolution of low-metallicity dwarf galaxies hosting the birth/coalescence of stellar/compact binaries generating GW150914-like signals. Finally, we focus on the mass and orbital properties of the above compact binary candidates assessing their impact on the resulting coalescence times and on selecting suitable galaxy hosts.
Synthesis and Characterization of Novel D-A Type Neutral Blue Electrochromic Polymers Containing Pyrrole[3-c]Pyrrole-1,4-Diketone as the Acceptor Units and the Aromatics Donor Units with Different Planar Structures
Authors: Yue Haoguo , Kong Lingqian , Wang Bo , Yuan Qing , Zhang Yan , Du Hongmei , Dong Yunyun , Zhao Jinsheng
Published: December 2019

Three soluble conjugated polymers, named BEDPP, FLDPP, and CADPP, were prepared through the Suzuki polymerized reaction, and employed benzene (BE), fluorene (FL), and carbazole (CA) as the donor units, respectively. The electron-deficient molecule 2,5-bis-(2-octyldodecyl)-3,6-bis-(5-bromo-thiophene)-pyrrole[3-c]pyrrole-1,4-diketone(DPP) was introduced and used as the acceptor unit. The properties of these three copolymers were studied by a series of detailed characterization analysis, including X-ray photoelectron spectroscopy (XPS), colorimetry, electrochemical measurements, spectroelectrochemistry, kinetics, quantitative calculation, and thermogravimetric (TG) analysis, etc. The results revealed that BEDPP displayed a blue color in the neutral state and a light brown color in the oxidized state, FLDPP exhibited a cyan color in the neutral state and a gray color in the oxidized state, while CADPP displayed pure blue color in the neutral state and a light gray color in the oxidized state. All these polymers possess narrow optical band gaps lower than 1.80 eV and satisfactory thermal stability. The kinetic characterization showed that the optical contrasts (ΔT%) in the near-infrared region were superior to the visible region. The optical contrasts of BEDPP, FLDPP, and CADPP are 41.32%, 42.39%, and 45.95% in the near-infrared region, respectively, which made them a good application prospect in the near-infrared region. Amid the three polymers, CADPP has the highest coloration efficiency (around about 288 cm2·C−1) and fast switching times (0.77 s in the coloring process and 0.52 s in the bleaching process) in the visible region, and the comprehensive performance of CADPP can be comparable to that of the reported D-A (Donor-Acceptor) type blue color polymers. In general, based on the good performances and the stable neutral blue color, the three polymers had profound theoretical significance for the development of electrochromic material and the completion of the RGB (Red, Green, Blue) color space.
Looking Beyond the Social: Religion as a Solution to Alienation in Xu Dishan’s, Bing Xin’s, and Su Xuelin’s Republican Era Literature
Authors: Elia Gina
Published: December 2019

I argue that by participating in religious cultural phenomena, the protagonists of Xu Dishan’s and Su Xuelin’s fiction cultivate values that allow them to overcome their sense of social alienation by making them feel more confident about their ability to strengthen their relationships with others. These values include selflessness in the literature of both authors, as well as compassion in Su Xuelin’s literature. I further argue that these two authors’ literary narratives use the category of religion to label these values as existing outside of the space of human social interactions. This then allows protagonists to view the cultivation of these values as an ostensibly perfected resolution to their feeling of social alienation, which in the first place is caused by the imperfect sphere of human social interactions. The two case studies upon which this study draws to exemplify the argument include Yuguan from Xu Dishan’s Yuguan and Xingqiu from Su Xuelin’s Thorny Heart.
Calibration of a Ground-Based Array Radar for Tomographic Imaging of Natural Media
Authors: Monteith Albert R. , Ulander Lars M. H. , Tebaldini Stefano
Published: December 2019

Ground-based tomographic radar measurements provide valuable knowledge about the electromagnetic scattering mechanisms and temporal variations of an observed scene and are essential in preparation for space-borne tomographic synthetic aperture radar (SAR) missions. Due to the short range between the radar antennas and a scene being observed, the tomographic radar observations are affected by several systematic errors. This article deals with the modelling and calibration of three systematic errors: mutual antenna coupling, magnitude and phase errors and the pixel-variant impulse response of the tomographic image. These errors must be compensated for so that the tomographic images represent an undistorted rendering of the scene reflectivity. New calibration methods were described, modelled and validated using experimental data. The proposed methods will be useful for future ground-based tomographic radar experiments in preparation for space-borne SAR missions.
An Object-Based Strategy for Improving the Accuracy of Spatiotemporal Satellite Imagery Fusion for Vegetation-Mapping Applications
Authors: Guan Hongcan , Su Yanjun , Hu Tianyu , Chen Jin , Guo Qinghua
Published: December 2019

Spatiotemporal data fusion is a key technique for generating unified time-series images from various satellite platforms to support the mapping and monitoring of vegetation. However, the high similarity in the reflectance spectrum of different vegetation types brings an enormous challenge in the similar pixel selection procedure of spatiotemporal data fusion, which may lead to considerable uncertainties in the fusion. Here, we propose an object-based spatiotemporal data-fusion framework to replace the original similar pixel selection procedure with an object-restricted method to address this issue. The proposed framework can be applied to any spatiotemporal data-fusion algorithm based on similar pixels. In this study, we modified the spatial and temporal adaptive reflectance fusion model (STARFM), the enhanced spatial and temporal adaptive reflectance fusion model (ESTARFM) and the flexible spatiotemporal data-fusion model (FSDAF) using the proposed framework, and evaluated their performances in fusing Sentinel 2 and Landsat 8 images, Landsat 8 and Moderate-resolution Imaging Spectroradiometer (MODIS) images, and Sentinel 2 and MODIS images in a study site covered by grasslands, croplands, coniferous forests, and broadleaf forests. The results show that the proposed object-based framework can improve all three data-fusion algorithms significantly by delineating vegetation boundaries more clearly, and the improvements on FSDAF is the greatest among all three algorithms, which has an average decrease of 2.8% in relative root-mean-square error (rRMSE) in all sensor combinations. Moreover, the improvement on fusing Sentinel 2 and Landsat 8 images is more significant (an average decrease of 2.5% in rRMSE). By using the fused images generated from the proposed object-based framework, we can improve the vegetation mapping result by significantly reducing the “pepper-salt” effect. We believe that the proposed object-based framework has great potential to be used in generating time-series high-resolution remote-sensing data for vegetation mapping applications.
Scotch Tape Optical Vapor Sensor for Ethanol–Methanol Mixtures
Authors: Angulo Barrios Carlos
Published: December 2019

A simple optical vapor sensor based on conventional Scotch adhesive tape, for analyzing ethanol–methanol mixtures, is proposed and demonstrated. The sensing signal relies on the variation of optical power transmitted through the tape, resulting from the response of the adhesive material to vapor sorption. The optical sensor exhibits high selectivity for ethanol vapor over methanol vapor. When exposed to vapors from ethanol–methanol liquid mixtures, the sensor shows a linear detection range of 0–100 vol%, and detection limits of 8.8 vol% ethanol and 17.6 vol% methanol. Repeatability, reproducibility, reversibility, and sensitivity to other volatile organic compounds are also studied.
Bulk and Surface Acoustic Wave Sensor Arrays for Multi-Analyte Detection: A Review
Authors: Länge Kerstin
Published: December 2019

Bulk acoustic wave (BAW) and surface acoustic wave (SAW) sensor devices have successfully been used in a wide variety of gas sensing, liquid sensing, and biosensing applications. Devices include BAW sensors using thickness shear modes and SAW sensors using Rayleigh waves or horizontally polarized shear waves (HPSWs). Analyte specificity and selectivity of the sensors are determined by the sensor coatings. If a group of analytes is to be detected or if only selective coatings (i.e., coatings responding to more than one analyte) are available, the use of multi-sensor arrays is advantageous, as the evaluation of the resulting signal patterns allows qualitative and quantitative characterization of the sample. Virtual sensor arrays utilize only one sensor but combine it with enhanced signal evaluation methods or preceding sample separation, which results in similar results as obtained with multi-sensor arrays. Both array types have shown to be promising with regard to system integration and low costs. This review discusses principles and design considerations for acoustic multi-sensor and virtual sensor arrays and outlines the use of these arrays in multi-analyte detection applications, focusing mainly on developments of the past decade.
Dry Coupling of Ultrasonic Transducer Components for High Temperature Applications
Authors: Bhadwal Neelesh , Torabi Milani Mina , Coyle Thomas , Sinclair Anthony
Published: December 2019

The viability for dry coupling of piezoelectric ultrasonic transducer components was investigated, using a thin foil of annealed silver as a filler material/coupling agent at each component interface. Criteria used for room temperature evaluation were centered on signal-to-noise ratio (SNR) and echo bandwidth, for a Li-Nb based transducer operating in pulse-echo mode. A normal clamping stress of only 25 MPa, applied repeatedly over three loading cycles on a precisely-aligned transducer stack, was sufficient to yield backwall echoes with a SNR greater than 25 dB, and a 3 dB bandwidth of approximately 65%. This compares to a SNR of 32 dB and a 3 dB bandwidth of 65%, achievable when all transducer interfaces were coupled with ultrasonic gel. The respective roles of a soft filler material, alignment of transducer components, cyclic clamping, component roughness, and component flatness were evaluated in achieving this high efficiency dry coupling, with transducer clamping forces far lower than previously reported. Preliminary high temperature tests indicate that this coupling method is suitable for high temperature and achieves signal quality comparable to that at room temperature with ultrasonic gel.
Research on Urban Bearing Capacity of Gas Supply Stations
Authors: Tan Xin , Zhang Penglin , Wang Junqiang , Hong Jiewen
Published: December 2019

Given the continuous optimisation of the energy structure, the proportion of natural gas consumption in China increases annually, the urban gas pipeline network continues to extend outward, and the supply range continues to expand. Although an increasing number of users can use natural gas, the coverage of the natural gas pipeline network remains low in some areas in China. A “point supply” pattern, which provides gas through liquefied natural gas (LNG), compressed natural gas (CNG) and liquefied petroleum gas (LPG) supply stations, has been developed to solve the problem of gas unavailability in areas not covered by the pipeline network. This pattern flexibly supplies gas, whose cost is low and market determined. Thus, the substantial development of these gas supply stations has been promoted. This pattern will continue to play an important role in the future. However, no unified standards for the construction of these gas supply stations have been provided, resulting in various problems, such as unreasonable location, inadequate management, potential risk and imbalance between supply and demand. On the basis of these concerns, this research attempts to study the urban bearing capacity of gas supply stations, provide some new ideas for the construction and planning of urban gas supply stations, and help promote sustainable urban development. The pressure–state–response model is adjusted to the pressure–state–capability model, which is used as a basis for proposing an evaluation index system and calculation models for the comprehensive evaluation of the urban bearing capacity of gas supply stations on city and country scales. The proposed methodology is used in a case study of urban agglomerations in the Yangtze River Delta.
A Conceptual Framework for Choosing Target Species for Wildlife-Inclusive Urban Design
Authors: Apfelbeck Beate , Jakoby Christine , Hanusch Maximilian , Steffani Emanuel Boas , Hauck Thomas E. , Weisser Wolfgang W.
Published: December 2019

Recent research has highlighted the significance of cities for biodiversity, making them important places for conservation in their own right. Current conservation approaches in cities are mostly defensive. Thus, they focus on remnant pockets of natural areas or try to protect particular species that occur in the built environment. These approaches are vulnerable to further urban development and do not create habitats. An alternative strategy is to make wildlife an integral part of urban development and thereby create a new habitat in the built-up area. Here we address the challenge of choosing target species for such wildlife-inclusive urban design. The starting point of our conceptual framework is the regional species pool, which can be obtained from geo-referenced species data. The existing habitat types on and around the development site and dispersal barriers limit the species numbers to the local species potential. In the next step, the site’s potential for each species is analyzed—how can it be upgraded to host species given the planned development and the life-cycle of the species? For the final choice of target species, traits related to the human–animal interaction are considered. We suggest that stakeholders will be involved in the final species selection. Our approach differs from existing practice, such as expert choice of priority species, by (1) representing an open process where many species are potential targets of conservation, (2) the involvement of stakeholders in a participatory way. Our approach can also be used at larger spatial scales such as quarters or entire cities.
Can the Famous University Experience of Top Managers Improve Corporate Performance? Evidence from China
Authors: Xu Weifeng , Ruan Qingsong , Liu Chang
Published: December 2019

With the continuous improvement of China’s overall education level, the number of top managers with famous university experience in listed companies has been increasing. The question then becomes whether the performance of the listed companies is better if there are more top managers with famous university experience in the top management team (TMT). Based on the sample of listed companies in China from 2008 to 2018, we adopted the two-way fixed effect model and panel propensity score matching (Panel-PSM) methodology to examine the impact of top managers with famous university experience on corporate performance and its mechanism. We found that the higher the proportion of top managers with famous university experience in the TMT, the better the corporate performance will be, and this positive effect is larger in companies with high business complexity. We also found that this effect is mediated by overconfidence of the TMT. The proportion of top managers with famous university experience in the TMT will inhibit the overconfidence of the TMT, which will ultimately benefit corporate performance.
Spatiotemporal Variation of Cold Eddies in the Upwelling Zone off Northeastern Taiwan Revealed by the Geostationary Satellite Imagery of Ocean Color and Sea Surface Temperature
Authors: Chung Hsiao-Wei , Liu Cheng-Chien
Published: December 2019

The upwelling zone off northeastern Taiwan (UZONT) is one of the hot spots with mesoscale ocean eddies (MOEs) and eddy-induced transports in the north Pacific Ocean. We start from the temporal and spatial variations in MOEs in the UZONT, based on the Himawari-8 SST product and the GOCI chlorophyll-a product time series, respectively. Their relationship with three major factors, including the Kuroshio, typhoon, and El Niño/La Niña events, are then investigated. The spatiotemporal variations in MOEs serve as ideal indicators by which to understand the influences on the UZONT due to interannual environmental factors and climate change.
Can Cross-Border Healthcare Be Sustainable? An Example from the Czech-Austrian Borderland
Authors: Böhm Hynek , Kurowska-Pysz Joanna
Published: December 2019

Cross-border public services are considered to be one of the possible tools to eliminate the periphery position of border regions. The Czech part of the Gmünd/České Velenice divided twin town faces the problem of very distant healthcare, as the closest hospital on its side of the border is at around a 50 min car-drive, whereas the hospital in Austrian Gmünd is within several minutes reach. This paper analyses whether cross-border healthcare provision could help to eliminate this problem. It describes the EU legislative framework for the cross-border healthcare provision and states that it has been rather underused until now, with a minor exception of the situation between European Communities’ founding members. In the Gmünd/České Velenice context, the functional partnership run by the Lower Austria as the key actor was created. Its ability to use the INTERREG programme has helped to create conditions for a sustainable cross-border healthcare, but only as a partial solution restricted on an outpatient care. The main identified barriers are of administrative nature. To a partial surprise of authors, the mental barrier plays a minor role and could be overcome by systemic measures implemented by partners of this initiative.
Physiological Effects on Coexisting Microalgae of the Allelochemicals Produced by the Bloom-Forming Cyanobacteria Synechococcus sp. and Nodularia Spumigena
Authors: Śliwińska-Wilczewska Sylwia , Barreiro Felpeto Aldo , Możdżeń Katarzyna , Vasconcelos Vitor , Latała Adam
Published: December 2019

Only a few studies have documented the physiological effects of allelopathy from cyanobacteria against coexisting microalgae. We investigated the allelopathic ability of the bloom-forming cyanobacteria Synechococcus sp. and Nodularia spumigena filtrates on several aspects related to the physiology of the target species: population growth, cell morphology, and several indexes of photosynthesis rate and respiration. The target species were the following: two species of green algae (Oocystis submarina, Chlorella vulgaris) and two species of diatoms (Bacillaria paxillifer, Skeletonema marinoi). These four species coexist in the natural environment with the employed strains of Synechococcus sp. and N. spumigena employed. The tests were performed with single and repeated addition of cyanobacterial cell-free filtrate. We also tested the importance of the growth phase in the strength of the allelopathic effect. The negative effects of both cyanobacteria were the strongest with repeated exudates addition, and generally, Synechococcus sp. and N. spumigena were allelopathic only in the exponential growth phase. O. submarina was not negatively affected by Synechococcus filtrates in any of the parameters studied, while C. vulgaris, B. paxillifer, and S. marinoi were affected in several ways. N. spumigena was characterized by a stronger allelopathic activity than Synechococcus sp., showing a negative effect on all target species. The highest decline in growth, as well as the most apparent cell physical damage, was observed for the diatom S. marinoi. Our findings suggest that cyanobacterial allelochemicals are associated with the cell physical damage, as well as a reduced performance in respiration and photosynthesis system in the studied microalgae which cause the inhibition of the population growth. Moreover, our study has shown that some biotic factors that increase the intensity of allelopathic effects may also alter the ratio between bloom-forming cyanobacteria and some phytoplankton species that occur in the same aquatic ecosystem.
Genetic Characteristics and Pathogenicity Analysis in Chickens and Mice of Three H9N2 Avian Influenza Viruses
Authors: Song Yafen , Zhang Yong , Chen Ling , Zhang Bing , Zhang Min , Wang Jingwen , Jiang Ying , Yang Chenghuai , Jiang Taozhen
Published: December 2019

H9N2 avian influenza is a remarkable disease that has circulated in domestic poultry in large regions of China and posed a serious threat to the poultry industry. The H9N2 virus can not only infect mammals directly, but also provide gene segments to generate novel, but lethal human reassortants. Therefore, it is important to study the evolution, pathogenicity, and transmission of the H9N2 virus. In this study, three H9N2 viruses isolated from chickens in different layer farms were identified. Phylogenetic analysis revealed that these H9N2 viruses were all multiple genotype reassortants, with genes originating from Y280-like, F/98-like, and G1-like viruses. Animal studies indicated that the AV1535 and AV1548 viruses replicated efficiently in the lungs, tracheas, spleens, kidneys, and brains of chickens; the viruses shed for at least 11 days post-inoculation (DPI) and were transmitted efficiently among contact chickens. The AV1534 virus replicated poorly in chickens, shed for 7 DPI, and were not transmitted efficiently among contact chickens. The AV1534 virus replicated well in mice lungs and caused about 2% weight loss. The AV1535 and AV1548 viruses were not able to replicate in the lungs of mice. Our results indicate that we should pay attention to H9N2 avian influenza virus surveillance in poultry and changes in the pathogenicity of them to mammals.