bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abiotic stresses.
Authors: Wehner Todd C. , Naegele Rachel P. , Myers James R. , Dhillon Narinder P. S. , Crosby Kevin 
Published: June 2020

Abstract

Numerous abiotic stresses impact yield, quality and adaptation of cucurbit crops under the diverse cultivation systems across the globe. Irrigation systems, elevation, soil type, solar radiation, wind, pathogens, fertility and genotype all interact to determine the degree to which abiotic stress may impact the crop. This chapters describes some abiotic stresses affecting cucurbit cultivation, such as cold, heat, drought, flooding, nutrient deficiencies and excesses, and salinity. Tolerance or resistance to abiotic stress factors has been documented in the germplasm of multiple cucurbit crops. Utilizing wild accessions, landraces and known resistance sources, genes for abiotic stress resistance are being identified and introgressed into cultivars with desirable fruit quality. With the new gene editing technology, it may be possible to modify these endogenous stress resistance genes to enhance their effects in the near future.
Neuroblastoma‐secreted exosomes carrying miR‐375 promote osteogenic differentiation of bone‐marrow mesenchymal stromal cells
Authors: Colletti Marta , Tomao Luigi , Galardi Angela , Paolini Alessandro , Di Paolo Virginia , De Stefanis Cristiano , Mascio Paolo , Nazio Francesca , Petrini Stefania , Castellano Aurora , Russo Ida , Caruso Roberta , Piga Simone , De Vito Rita , Pascucci Luisa , Peinado Hector , Masotti Andrea , Locatelli Franco , Di Giannatale Angela 
Published: June 2020

ABSTRACTBone marrow (BM) is the major target organ for neuroblastoma (NB) metastasis and its involvement is associated with poor outcome. Yet, the mechanism by which NB cells invade BM is largely unknown. Tumour microenvironment represents a key element in tumour progression and mesenchymal stromal cells (MSCs) have been recognized as a fundamental part of the associated tumour stroma. Here, we show that BM‐MSCs isolated from NB patients with BM involvement exhibit a greater osteogenic potential than MSCs from non‐infiltrated BM. We show that BM metastasis‐derived NB‐cell lines secrete higher levels of exosomal miR‐375, which promotes osteogenic differentiation in MSCs. Of note, clinical data demonstrate that high level of miR‐375 correlates with BM metastasis in NB patients. Our findings suggest, indeed, a potential role for exosomal miR‐375 in determining a favourable microenvironment in BM to promote metastatic progression. MiR‐375 may, thus, represent a novel biomarker and a potential target for NB patients with BM involvement.
Averting cumulative lifetime attributable risk (LAR) of cancer by decontamination of residential areas affected by a large-scale nuclear power plant fallout: time aspects of radiological benefits for newborns and adults
Authors: Rääf C , Finck R , Martinsson J , Hinrichsen Y , Isaksson M 
Published: June 2020

Abstract
The averted cumulative lifetime attributable risk (LAR), the residual dose and highest ground deposition of 137Cs complying with a reference dose level of 20 mSv yr−1 to an individual returning after one year to an area contaminated by unfiltered releases of fission products from a nuclear power plant (NPP) were evaluated by applying an existing exposure model designed to compute age- and gender-dependent time-integrated LAR. The model was applied to four types of nuclear fallout scenarios, partly based on data from the Chernobyl and Fukushima releases and from theoretical source terms from Swedish NPPs. For rapid decontamination measures that achieve a 50% relative reduction in external dose rate within 1 year, compliance with the reference level 20 mSv yr−1 can be attained for an initial 137Cs ground deposition of up to 2 MBq m−2 with relaxed food restrictions. This compliance can be attained at even higher ground deposition (up to 4.5 MBq m−2) if using the strict food restrictions employed in Japan after 2011. Considering longer than 1 year return times it was also found that the benefit of implementing decontamination decreases rapidly with time (2–3 years half-time), especially if the fallout has a high initial 134Cs to 137Cs activity ratio and if the ecological half-time of the external dose rate is short (<5 years). Depending on fallout scenario the averted cumulative LAR for newborn girls by decontamination that is achieved after 5 years is only between 6% and 11% of that obtained by evacuation alone during the same time, indicating a rather limited radiological benefit of decontamination if delayed more than a few years. We conclude that decision makers and emergency response planners need to consider that protracted decontamination measures may have limited radiological benefit compared with evacuation in terms of averted future cancer cases, albeit it may have other societal benefits.
Wettability and aging of polylactide films as a function of AC-discharge plasma treatment conditions
Authors: Demina T S , Piskarev M S , Shpichka A I , Gilman A B , Timashev P S 
Published: June 2020

Abstract
Plasma treatment is among the most versatile and promising tools for modifying the properties of polymeric surfaces. It is mainly used to control the hydrophilic-hydrophobic balance of a surface and to optimize its adhesion properties, including material/cell interactions. From this point of view, a wide set of variable plasma processing conditions and their effect on surface wettability, as well as the tendency of plasma-treated surfaces to restore their initial characteristics after storage, require preliminary optimization of the treatment conditions. This work is aiming to study the effect of AC-discharge plasma treatment conditions (duration, power, frequency) on the wettability contact angle of poly(L, L-lactide) film and to evaluate the aging of this effect in time as a function of the plasma treatment parameters.
Diagnostics of process plasma used for the production of memristive devices
Authors: Cipo J , Schlichting F , Zahari F , Gauter S , Kohlstedt H , Kersten H 
Published: June 2020

Abstract
Memristive devices have been the object of intensive studies for non-volatile memories, neuromorphic engineering and image processing algorithms. The intrinsic properties of these devices are determined by its I-V characteristics influenced by different process parameters. The double-barrier memristive devices investigated in this work are based on the motion of charged species, i.e. oxygen vacancies or ions, within a NbOx layer. Since the layers are deposited by magnetron sputtering, it is important to understand the physics of the discharge and its effect on the film properties.
For plasma diagnostics we used a calorimetric probe, which can be operated simultaneously as a passive thermal probe for energy flux measurement and as a planar Langmuir probe for measuring the ion current, the floating and plasma potentials and the electron temperature. In particular, we investigated the reactive sputter deposition of the NbOx layer by a floating and a biased probe. The parameters were determined in dependence on the radial position of the probe across the substrate region. The results allowed us to find correlations between the plasma parameters and the electrical properties of the memristive devices produced on one 100-mm wafer. Furthermore, we could point out the dominating factors affecting strongly the properties of these thin films.
Particle-in-cell simulations of an inverted sheath
Authors: Gomez I , Valič A , Gyergyek T , Costea S , Kovačič J 
Published: June 2020

Abstract
An inverted sheath is simulated by particle-in-cell simulations using the XPDP1 code. It is shown that a stable monotonically decreasing potential structure can be formed in a bounded plasma system, where positive ions and source electrons are injected from the right-hand side (source) electrode and emitted electrons are injected from the left-hand side (collector) electrode. Such inverted sheath structure is created in the absence of collisions or ionization, provided that the ratio of injection fluxes of both electron groups is large enough. In this work preliminary results are reported and some effects of different ion injection are illustrated.
Theoretical determination of the gas temperature in a nanosecond pulsed longitudinal discharge exciting high-power strontium atom lasers
Authors: Temelkov K A , Slaveeva S I , Kostadinov I K , Fedchenko Yu I 
Published: June 2020

Abstract
Assuming that the gas temperature varies only in the radial direction, an analytical solution of the steady-state heat conduction equation is found for a uniform power input in various gas mixtures and for different discharge tube designs. For this purpose, the heat conductivities of several 2- and 3-component gas mixtures are obtained under gas-discharge conditions optimal for the strontium atom laser.
Plasimo modeling of hollow-cathode geometry: laser tube configuration for sputtering metal-vapor lasers
Authors: Yordanova D , Temelkov K , Mihailova D , Van Dijk J 
Published: June 2020

Abstract
We report results of the studies of a new version of a hollow-cathode discharge, namely, a multiple hollow-cathode discharge. The geometry comprises a main cylindrical cathode, which defines the active laser volume, and a number of short cylindrical side cathodes arranged radially to the main cathode along its length. PLASIMO’s Drift-Diffusion module is used to describe numerically the new laser tube configuration and to demonstrate its advantages.
Heat distribution simulation in electron-beam surface modification of 316L stainless steel samples
Authors: Koleva E , Tsonevska T , Koleva L , Vutova K , Mladenov G , Naplatanova M , Trushnikov D , Varushkin S 
Published: June 2020

Abstract
A time-dependent heat model is implemented for the simulation of the heat distribution in 316L stainless steel samples during electron-beam irradiation. The influence is studied of the electro-beam power and processing time on the temperature field produced in the samples. The simulation results are compared with real experimental data of electron-beam surface modification of 0.5-mm-thick 316L stainless steel samples using the ELIT-60 installation in the Institute of Electronics BAS. The simulation and the experimental results show good agreement.
Influence of the processes of additional phosphate post-treatment of ceria conversion coatings deposited on Al 1050 on their corrosion protective behavior
Authors: Andreeva R , Stoyanova E , Tsanev A , Stoychev D 
Published: June 2020

Abstract
Systematic studies were carried out with respect to the elucidation of the role of additional “post-treatment” immersion phosphate processing on conversion corrosion protective ceria coatings CCOC deposited on aluminium Al 1050. Thereupon, the influence of various compositions of the CCOC as well as the conditions of such treatment were studied, based on solutions of Na3PO4 or NH4H2PO4. The results obtained with respect to the corrosion behavior, respectively the corresponding changes in the chemical composition of the studied corrosion-protective systems, give us the reason to suppose that the phosphate layers formed on the CCOC play the role of not only protective barrier coating, but they also change the kinetics of the conjugated electrochemical reactions characterizing the corrosion of aluminium. Key words: aluminum, pre-treatment, cerium-containing conversion films, corrosion
Nanoindentation study of the mechanical properties and deformation behavior of nanoporous alumina films
Authors: Bankova A , Videkov V , Tzaneva B , Mitov M , Potiron S , Molinari M 
Published: June 2020

Abstract
Over the past decade, anodic aluminium oxide (AAO) has become one of the most widely used materials as a platform for developing new types of devices in micro- and nanotechnology. Due to the potential use of highly ordered honeycomb porous AAO membranes in many engineering applications, considerable attention is being paid to the mechanical characterization of such thin films. In this study, the mechanical properties and deformation behavior of a nanoporous alumina film were investigated by nanoindentation. AAO films with an average pore diameter of 40 nm were fabricated electrochemically. The morphology and the mechanical properties of AAO were studied using scanning electron microscopy and nanoindentation, respectively. The force-displacement dependences obtained revealed that in the case of a freestanding AAO membrane the sample demonstrates extremely high elasticity. The indentation modulus and the hardness were found to decrease nonlinearly with an increase in the applied force.
Initial conditions for preparation of thin AlN films by atomic layer deposition
Authors: Beshkova M , Blagoev B S , Mehandzhiev V , Yakimova R , Georgieva B , Avramova I , Terziyska P , Kovacheva D , Strijkova V 
Published: June 2020

Abstract
Thin AlN films were grown on Si substrates in a Beneq TFS-200 ALD reactor. The atomic layer deposition (ALD) process consisted of two half cycles – aluminum adsorption and nitridization separated by a purging step. TMA (trimethylaluminum) and NH3 were used as precursors, and nitrogen (N2), as a carrier gas. The pulse duration, purging time, deposition temperature and other deposition conditions were varied to obtain AlN films with desired properties. The X-ray diffraction (XRD) data showed that the AlN films had an amorphous character. The films’ chemical composition and bonding states were investigated by X-ray photoelectron spectroscopy. The high resolution Al 2p and N 1s spectra confirmed the presence of AlN with peaks located at 74.1 eV and 397.7 eV, respectively, for all layers.
Corrosion resistance of sol-gel ZrO2 coatings deposited on stainless steel
Authors: Stambolova I , Dimitrov O , Shipochka M , Yordanov S , Blaskov V , Vassilev S , Jivov B , Simeonova S , Balashev K , Grozev N , Lakov L 
Published: June 2020

Abstract
Corrosion-resistant ZrO2 coatings were deposited on stainless steel plates using organic (A) and inorganic (B) Zr precursors containing polyethylene glycol as structure directing agent. The dipping-drying cycles were repeated five times; the coatings were then treated at 500 °C. The samples were studied by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and by automated contact-angle goniometry. The corrosion resistance of the ZrO2 coatings were examined in NaCl and artificial sea water. The XRD analyses revealed a crystallized monoclinic ZrO2 phase. The AFM observation proved that after the corrosion attack the surface had no signs of corrosion (scratches or cracks). The A and B coatings had corrosion rates of 4×10−5 and 2×10−4 g/m2 h, respectively. The A coatings possessed a fine grained structure and a lower wettability (contact angle of 107°) and a lower oxygen content than the B coatings, which determined their better corrosion properties in both corrosive media.
Development of ALD ZnO:Al as transparent conductive films
Authors: Napoleonov B , Marinova V , Petrova D , Blagoev B , Avramova I , Dimitrov D 
Published: June 2020

Abstract
We report the deposition of ultrathin Al-doped ZnO (AZO) films by using atomic layer deposition (ALD) and results from X-ray photoelectron spectroscopy (XPS) and photoelectrical measurements. The AZO films were deposited on glass, silicon and polyethylene terephthalate (PET) substrates and their structural and photoelectrical properties were measured and discussed. Based on the results, selected AZO films deposited on PAT were implemented as transparent electrodes in a polymer dispersed liquid crystal display device (PDLC). The electro-optical modulation characteristics of these devices are comparable to those of devices using commercial ITO electrodes.
Deposition and study of N-In co-doped sol-gel ZnO films
Authors: Ivanova T , Harizanova A , Koutzarova T , Vetruyen B 
Published: June 2020

Abstract
Single and doped ZnO films are successfully deposited by a sol-gel method. ZnO:N, ZnO:In and co-doped (N, In) ZnO films are thermally treated at 300 °C and 600 °C. Their structural, vibrational and optical properties are studied. The ZnO:In:N films crystallize in a wurtzite phase, revealing a preferential orientation in the 002 plane. FTIR analysis shows that the two dopants affect greatly the shapes and positions of the absorption features. The ZnO:N:In films are highly transparent above 90% in the visible spectral range. The ZnO:In and ZnO:N:In films annealed at 400-600°C show a tendency of narrowing the optical band gap compared to ZnO.
Electrochromic and optical study of sol-gel TiO2-MnO films
Authors: Ivanova T , Harizanova A , Koutzarova T , Vetruyen B 
Published: June 2020

Abstract
We present a study on the structural, optical and electrochromic properties of sol-gel films of TiO2 and TiO2-MnO. The XRD analyses show that the incorporation of Mn in the TiO2 host matrix inhibits the crystallization process, as compared to single TiO2 films, which are well crystallized in anatase phase. This conclusion is supported by FTIR analysis. Adding Mn to the TiO2 films leads to a significant narrowing of the optical band gap. The electrochromic characteristics of TiO2-MnO films are better than those of the single titanium dioxide films after annealing at 300 °C.
Modification of thin carbon films by UVC light
Authors: Milenov T , Avramova I , Dikovska A , Avdeev G , Mladenoff J , Kolev S , Valcheva E 
Published: June 2020

Abstract
We modified by UVC light single to few-layered nano-sized graphene films deposited by pulsed laser deposition (PLD) on ~300-nm SiO2/Si substrates. The samples were irradiated by UVC lamps (wavelength of 254 nm) for 15, 30, 60 and 90 minutes in air. The influence of the modification was evaluated by following the changes in the X-ray photoelectron and Raman spectra of the samples after UVC irradiation.
Deposition of vertical carbon nanosheets by MPECVD at atmospheric pressure
Authors: Marinov S , Vachkov V , Kiss’ovski Zh 
Published: June 2020

Abstract
The deposition process is studied of vertical carbon nanosheets by microwave (MW) plasma-enhanced chemical vapor deposition (PECVD) at atmospheric pressure. A coaxial MW plasma source with a surface-wave discharge at 2.45 GHz produces plasma in a gas mixture (Ar/H2/CH4) in the processing chamber. The emissive spectra of the plasma column in pulsed regime of the source are registered by an iHR550 spectrometer. The light from the plasma column is collected by a lens system connected to the spectrometer by an optical fiber. The dependence of the gas temperature in the plasma column on the absorbed MW power is obtained from the recorded OH-band and CN-band spectra by using the LIFBASE program. The plasma density is estimated from the Stark broadening of the Hβ-line, while the electron temperature is estimated by the line-ratio method using argon lines. The composition of the outlet gases from the chamber is measured and analyzed by an Agilent Micro gas chromatograph. The results obtained demonstrate the high efficiency of the methane decomposition process in the hot region of the plasma column (T
g ~ 3000 K). The deposition of vertical carbon nanosheets is carried out at fixed plasma parameters and controlled substrate temperature. Cu plate and Ni-foam are used as substrates. The carbon nanostructures formed on the metallic substrates are studied by SEM; the dependence is thus obtained of their morphology on the plasma parameters, gas temperature and substrate temperature. The structures are confirmed as graphene sheets via Raman spectroscopy. The results demonstrate the viability of our system for deposition of vertical carbon sheets at atmospheric pressure.
Very thin carbon-based films for transmissive photocathodes
Authors: Balalykin Nikolay I , Huran Jozef , Nozdrin Mikhail A , Sasinková Vlasta , Kováčová Eva , Kobzev Alexander P , Shirkov Grigory D 
Published: June 2020

Abstract
Very thin carbon-based nitrogen-doped films of different thicknesses were deposited on double-side polished sapphire substrates by RF reactive magnetron sputtering. RBS and ERD were used to determine the elemental concentration in the films, and Raman spectroscopy, to determine their chemical structure. The RBS and ERD analyses indicated that the films contained carbon, nitrogen and small amounts of hydrogen and oxygen. The Gaussian-fitted and identified Raman spectra of the films showed the D and G bands in the range 1000-1800 cm−1, and the 2 D and D+G bands, in the range 2500-3100 cm−1. The photo-induced (pulsed laser, 266 nm) electron emission properties of the films were determined by measuring the cathodes’ bunch charge and calculating their quantum efficiency. The paper discusses the structural properties of the very thin nitrogen-doped carbon-based films deposited on a sapphire substrate with different thicknesses in view of their use as backside-illuminated transmissive vacuum photocathodes.
Ellipsometric characterization of CrTiAlN coating deposited at low temperatures by unbalanced magnetron sputtering
Authors: Chitanov V , Kolaklieva L , Cholakova T , Sharif R , Hesser G , Hinterreiter A , Kakanakov R , Hingerl K 
Published: June 2020

Abstract
Ellipsometric characterization is presented of a CrTiAlN hard coating deposited by unbalanced magnetron sputtering at low temperatures. Such coatings find applications where the tool material cannot withstand temperatures exceeding 200 °C. The Cr/CrN/CrTiAlN coatings deposited using the UDP-850 equipment is characterized by UV-VIS and IR ellipsometry. A FIB cross-section is made and the thickness of the coating is measured using SEM. The roughness of the coating surface is determined by AFM. The ellipsometric measurements yielded data on the phase difference Δ, amplitude ratio ψ, the frequency dependent real (ε1(ω)) and imaginary (ε2(ω)) part of the dielectric function and the corresponding refractive and extinction indexes n(ω) and k(ω). The optical parameters are modelled by regression analysis implemented using the WVASE© software. A very good fit is achieved between the measured optical data and the corresponding models. The results show that the ellipsometric characterization data can be used to determine the surface structure, chemical composition and optical reflection characteristics of CrTiAlN hard coatings.
Composition, structure and adhesion of cathodic-arc and glow-discharge deposited TiN/TiO2 coatings: a case study
Authors: Nikolova M P , Valkov S , Yankov E , Petrov P 
Published: June 2020

Abstract
Titanium-based vacuum coatings, such as TiN and TiO2, are being widely used for functionalization of the surfaces and for forming protective surface layers for a number of applications. In this study, TiN/TiO2 coatings were deposited by two physical vacuum deposition (PVD) methods: cathodic-arc (for TiN) and glow-discharge (for TiO2) deposition. We studied the bilayer film composition, structure and properties by means of X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), and scratch test analysis. The XRD spectrum indicated the presence of both anatase and rutile TiO2 phases, together with TiN reflections. The Ti 2p, O 1s and N 1s core level of XPS spectra in the depth of the oxide up to the oxide-nitride interface indicated intimate heterojunction between the layers. This results in a lower coefficient of friction and improved adhesion strength of the TiN/TiO2 film compared with pristine TiN coating.