bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of atomic layer deposition of Al2O3 films as possible template for graphene transfer
Authors: Blagoev B S , Delibatov D A , Mehandzhiev V B , Sveshtarov P , Terziyska P , Avramova I , Rafailov P M
Published: April 2022

Nanofilms of aluminium oxide Al2O3 (ALO) were grown on Si, Cu and graphene/Cu substrates by atomic layer deposition (ALD). Trimethylaluminium (TMA) and deionized (DI) water were used as precursors for the ALD process. In order to obtain the ALD temperature window for the above-mentioned precursors, ALO nanofilms were deposited on Si substrates at temperatures ranging from 50 °C to 300 °C. Based on ellipsometry measurements of the films thickness, the growth rate of ALO films obtained was between 1.15 Å/cycle and 1.25 Å/cycle. Ellipsometry and XPS analyses showed that the optimal growth temperature for ALO films is between 150 °C and 200 °C. A graphene layer was grown on a Cu foil by chemical vapor deposition (CVD) and coated with an ALD ALO nanofilm. Raman spectroscopy was used to characterize the influence of ALO films deposition on the graphene layer. A Raman intensity enhancement for all graphene bands in the Al2O3/graphene/Cu sample was observed.
Improvement in the gas-sensing properties of a ZnO:Zn2TiO4 composite sensor by light irradiation
Authors: Atanasova G , Dilova T , Dikovska A , Nikov Ru , Nedyalkov N
Published: April 2022

In the present study, we demonstrate the application of highly porous ZnO:Zn2TiO4 nanocomposites as gas sensors. The composite sensor elements were prepared by pulsed laser deposition performed in air at atmospheric pressure. Gas detection was achieved through irradiating the sensor surface with UV light. The gas-sensing properties of the composite sensor were studied under exposure to ammonia, carbon monoxide, ethanol, and acetone. The highest response rate of the sensor element was observed in the case of exposure to carbon monoxide, with detection below 1 ppm being demonstrated. The influence was investigated of the additional light irradiation on the response and the times of response and recovery of the sensor elements. It was found that illuminating the sensor surface with blue light increased the sensor response to all tested gases, while a red-light irradiation enhanced the sensor element selectivity to carbon monoxide.
Plasmonic stop-band filter based on an MIM waveguide coupled with cavity resonators
Authors: Zegaar Imane , Hocini Abdesselam , Khedrouche Djamel , Ben salah Hocine , bahri Hocine
Published: April 2022

In this study, we propose and simulate in the NIR region a tunable stop-band filter based on an MIM waveguide coupled to a triangular cavity. The transmission spectra of the filter are obtained using the R-Soft CAD software based on the two-dimension (2D) finite-difference time-domain (FDTD) method, which uses perfectly matched layers (PML) to absorb the outgoing energy fields. A stop-band plasmonic filter with a large bandwidth and high bandpass transmission is achieved by adding another triangular cavity resonator. One can also control the range filtered and the shift of the central wavelength by tuning the second triangular cavity parameters. This structure has important applications in highly integrated photonic circuits.
Organic bulk heterojunction solar cells spin-coated in ambient environment on flexible and glass substrates
Authors: Gergova R , Sendova-Vassileva M , Popkirov G , Dikov Hr , Grancharov G , Terziyska P
Published: April 2022

Organic solar cells based on Poly (3-hexylthiophene) [6,6]-phenyl C61-butyric acid methyl ester (P3HT-PCBM) were fabricated in standard architecture by spin-coating on glass and on flexible polyethylene terephthalate (PET) substrates in ambient laboratory environment. In addition to the conventional DC characterization, impedance spectroscopy was used in order to study the capacitive behavior of the devices and obtain their electrical parameters. In combination with the electrical characterization methods, laser-beam-induced current (LBIC) measurements were used as a non-destructive method of mapping the photocurrent distribution and analyzing local device failures and macroscopic defects (shunts, dark spots, defects). The results of the study can be used to develop guidelines for the development and design of P3HT:PCBM solar cells in ambient environment.
Conversion of CO2 in a pulsed arc discharge
Authors: Vasilev V , Iordanova S , Vladkov E , Kolev St
Published: April 2022

We present a study of CO2 gas conversion into a mixture of CO2, CO and O2 by means of a pulsed arc discharge at atmospheric pressure. The CO2 molecule is dissociated as a result of the interaction with the highly energetic electrons and excited species produced in the plasma domain. The plasma conversion of CO2 provides a relatively simple approach to CO2 conversion without the need of special materials required by chemical reactors. In this study, the discharge operates at atmospheric pressure, which leads to a reduced efficiency compared to the low pressure operation due to the additional electron losses via elastic collisions. The operation at atmospheric pressure, however, provides simplicity, robustness and low cost of the discharge system, which makes it very attractive from an industrial point of view. Further, we use a pulsed discharge, which, in comparison to the DC discharges, provides additional possibilities for optimizing the dissociation process by controlling precisely the energy input into the plasma. This is achieved by controlling the pulse repetition rate and duty ratio in addition to the discharge current and gas flow characteristics. We present results for the CO2 dissociation rate and energy efficiency for a wide range of different discharge parameters.
Vertical and near-horizontal scanning lidar observations of aerosol loads over Sofia, Bulgaria, in the presence of Saharan dust
Authors: Peshev Z , Deleva A , Chaikovsky A , Pescherenkov V , Vulkova L , Dreischuh T
Published: April 2022

Intrusions of extraneous aerosols and their interactions with locally produced aerosols result in serious climatic, ecological and health effects and consequences. In this work, we analyze results of lidar observations during Saharan dust loads in the atmosphere above the city of Sofia. Two types of measurements are described, namely, vertical lidar sounding and near-surface aerosol mapping by quasi-horizontal lidar scanning. The temporal dynamics of the aerosol density vertical distribution is displayed by color-mapped time series of range-corrected lidar signals. The resulting time-averaged profiles of the backscattering coefficients at two lidar wavelengths (532 nm and 1064 nm) were retrieved and the topological parameters of the detected aerosol fields were determined. The aerosols’ microphysical characteristics and their height distribution were estimated by calculating the backscatter-related Ångström exponent. Presented and analyzed are results of vertical profiling of the total and mode volume concentration for the aerosol/dust fractions obtained by using the inversion code LIRIC-2 based on combined synergistic use of data from the CALIPSO satellite on-board lidar and sun-photometer data. The quasi-horizontal mapping of near-ground aerosols was carried out over a large urban area of the city of Sofia of about 25 km2 within a 50° angular sector in a south-western direction. The results presented in the work demonstrate the capabilities of the combined approach including lidar, radiometer, satellite measurements and theoretical modeling in conducting effective ecological monitoring of the atmospheric aerosol pollution.
Accuracy comparison of intraoral versus laboratory scanners used in the contemporary dental practice
Authors: Galeva H , Uzunov T , Sofronov Y , Todorov G
Published: April 2022

The aim of this in vitro study was to compare the quality of the data obtained by intraoral and by laboratory 3D scanners. An artificial jaw with an acrylic tooth prepared for a full metal ceramic crown was used as a master model of the prosthetic field. A reference model was created by scanning this field by a coordinate measuring machine (CCM). The acrylic master model was scanned by four scanners using three different methods and six digital models were obtained. They were divided in three groups - direct intraoral scanning (DIS), laboratory stone scanning (LSS) and laboratory conventional impression scanning (LCIS). Each scan was saved in the STL file format. Using a computer program, each of the six digital models were compared with the reference model created by the CCM and the results were displayed as color maps. The minimal acceptable deviation was defined as the deviation from the digital standard within the ± 0.02 mm limits. Thus, the LSS group exhibited an average of 13.5% points within these limits, followed by the LCIS group with 17.25%. The result for the DIS group was 44.75%.
Laser annealing of bimetal porous structures produced by PLD in open air
Authors: Nikov Ru , Nikov Ro , Nedyalkov N , Dikovska A , Grochowska K
Published: April 2022

This work presents experimental results on laser annealing of bimetal structures produced by pulsed laser deposition in air at atmosphere pressure. The initial structures are deposited in open air by laser ablation of a rotating target consisting of two sections – Au and Ag. The ablation process is carried out by nanosecond pulses delivered by a Nd:YAG laser system emitting the wavelength of 355 nm. In open air, the laser ablation results in the formation of nanoparticles (NPs) and NP aggregates; during a prolonged deposition, these grow on the substrate into a 3D porous structure. The as-deposited structures are then annealed by laser pulses using the same laser system. The morphology of the annealed samples is studied in relation to the laser processing by varying the laser fluence and the number of the laser pulses. It is found that under certain conditions, the laser annealing leads to the formation of a 2D array of bimetal NPs on the substrate. The optical response of such structures composed by noble metals (such as Au and Ag) or their alloys is associated with a strong absorption in the visible spectral range known as surface plasmon resonance. Special attention is paid to the influence of the annealing parameters on the optical properties of the samples prepared.
Electrical characterization of memory capacitors for nonvolatile memory applications based on nanolaminated HfO2/Al2O3 and Al-doped HfO2 stacks
Authors: Spassov D , Paskaleva A , Stanchev T , Ivanov Tz
Published: April 2022

Memory capacitors with atomic-layer-deposited HfO2/Al2O3 nanolaminated layers and Al-doped HfO2 charge trapping layers were investigated through capacitance-voltage (C-V) and current-voltage (I-V) measurements. The dielectric constant of the multi-dielectric stack comprising 20-nm Al2O3 blocking oxide, a HfO2-based layer and 2.4-nm tunnel SiO2 does not depend on the manner of Al-introduction in HfO2.The stacks exhibit a negative oxide charge of about -5.1×1011 cm−2 and -2.5×1011 cm−2 for the structures with nanolaminated and doped layers, respectively. The Al-doping of HfO2 is found to produce lower leakage currents. A sublinear behavior of the current-voltage curves is observed in the range of -20 ÷ +10 V for both HfO2-based stacks. Memory windows of ∼ 1 V when charging with ±27-V voltage pulses are obtained; the data suggests that electron trapping is better pronounced in the HfO2/Al2O3 nanolaminate, while positive charge accumulation prevails in the Al-doped HfO2 layers.
Nanosecond laser ablation of nitride ceramics in liquid
Authors: Nikov Ro , Nedyalkov N , Nikova T , Aleksandrov L
Published: April 2022

The work presents results on nanosecond laser ablation of nitride ceramics immersed in a liquid medium. AlN and Si3N4 ceramic plates were used targets, and double distilled water was used as a liquid medium. Radiation of a nanosecond Nd:YAG laser system was used in the ablation process with the purpose of studying the influence of the laser fluence and number of pulses on the target surface morphology. The morphology and phase composition of the structured surfaces were explored by scanning electron microscopy and X-ray diffraction measurements, respectively. The optical properties of the obtained colloids were investigated by transmission measurements in the UV-Vis spectral ranges.
Time-of-flight methodologies with large-area diamond detectors for the effectively characterization of tens MeV protons
Authors: Salvadori M. , Andreoli P.L. , Cipriani M. , Cristofari G. , De Angelis R. , Malko S. , Volpe L. , Perez Hernandez J.A. , Apiñaniz J.I. , Morace A. , Antici P. , Migliorati M. , Di Giorgio G. , Consoli F.
Published: April 2022

A novel detector based on a polycrystalline diamond sensor is here employed in an advanced time-of-flight scheme for the characterization of energetic ions accelerated during laser-matter interactions. The optimization of the detector and of the advanced TOF methodology allow to obtain signals characterized by high signal-to-noise ratio and high dynamic range even in the most challenging experimental environments, where the interaction of high-intensity laser pulses with matter leads to effective ion acceleration, but also to the generation of strong Electromagnetic Pulses (EMPs) with intensities up to the MV/m order. These are known to be a serious threat for the fielded diagnostic systems. In this paper we report on the measurement performed with the PW-class laser system Vega 3 at CLPU (∼30 J energy, ∼1021 W/cm2 intensity, ∼30 fs pulses) irradiating solid targets, where both tens of MeV ions and intense EMP fields were generated. The data were analyzed to retrieve a calibrated proton spectrum and in particular we focus on the analysis of the most energetic portion (E > 5.8 MeV) of the spectrum showing a procedure to deal with the intrinsic lower sensitivity of the detector in the mentioned spectral-range.
Integration and commissioning of the ATLAS Muon-to-Central-Trigger-Processor Interface for Run-3
Authors: Perrella S. , Afik Y. , Armbruster A. , Czodrowski P. , Ellis N. , Haas S. , Koulouris A. , Kulinska A.M. , Marzin A. , Pauly T. , Ryjov V. , Sanfilippo L. , Simoniello R. , Spiwoks R. , Vichoudis P. , Wyzlinski M. , Wengler T.
Published: April 2022

The Muon-to-Central Trigger Processor Interface was completely redesigned as part of the ATLAS Level-1 trigger upgrade for Run 3 of the Large Hadron Collider. The new system is implemented as a single AdvancedTCA module, using three large state-of-the-art FPGAs and high-density fiber-optic modules. Trigger information from the muon trigger detectors are received through 208 high speed links, while 60 links are used to send processed trigger information to the L1 Topological Trigger Processor and the Central Trigger Processor. Extensive integration tests with all input and output systems have shown that the data transfer is stable and reliable. We present results from integration tests with connected sub-systems as well as commissioning of the Muon-to-Central Trigger Processor Interface in the ATLAS experiment.
Reconstructing past fossil-fuel CO2 concentrations using tree rings and radiocarbon in the urban area of Medellín, Colombia
Authors: Vásquez Marileny , Lara Wilson , del Valle Jorge I , Sierra Carlos A
Published: April 2022

To meet international and national commitments to decrease emissions of fossil fuels, cities around the world must obtain information on their historical levels of emissions, identifying hotspots that require special attention. Direct atmospheric measurements of pollution sources are almost impossible to obtain retrospectively. However, tree rings serve as an archive of environmental information for reconstructing the temporal and spatial distribution of fossil-fuel emissions in urban areas. Here, we present a novel methodology to reconstruct the spatial and temporal contribution of fossil-fuel CO2 concentration ([CO2F]) in the urban area of Medellin, Colombia. We used a combination of dendrochronological analyses, radiocarbon measurements, and statistical modeling. We obtained annual maps of [CO2F] from 1977 to 2018 that describe changes in its spatial distribution over time. Our method was successful at identifying hotspots of emissions around industrial areas, and areas with high traffic density. It also identified temporal trends that may be related to socioeconomic and technological factors. We observed an important increase in [CO2F] during the last decade, which suggests that efforts of city officials to reduce traffic and emissions did not have a significant impact on the contribution of fossil fuels to local air. The method presented here could be of significant value for city planners and environmental officials from other urban areas around the world. It allows identifying hotspots of fossil fuels emissions, evaluating the impact of previous environmental policies, and planning new interventions to reduce emissions.
Shifting concerns for the EU ETS: are carbon prices becoming too high?
Authors: Gerlagh Reyer , Heijmans Roweno J R K , Einar Rosendahl Knut
Published: April 2022

Carbon prices in the EU Emissions Trading Scheme (EU ETS) have risen from around 5 euro per ton of CO2in 2017 to above 90 euro in 2021. One probable explanation is the cancellation mechanism implemented along with the Market Stability Reserve (MSR) of the EU ETS in 2018. We identify realistic conditions under which the MSR results in truly massive cancellation of emissions allowances, pointing to the steepness of the emissions pathway over time as essential. A flattening of the emissions pathway implies huge reduction in cumulative emissions, suggesting much higher ETS prices. The concerns about too low and ‘ineffective’ carbon prices may turn into concerns for too high prices. The results have important ramifications for planned revisions of the EU ETS.
Dimension towers of SICS: II. Some constructions
Authors: Bengtsson Ingemar , Srivastava Basudha
Published: April 2022

A SIC is a maximal equiangular tight frame in a finite dimensional Hilbert space. Given a SIC in dimension d, there is good evidence that there always exists an aligned SIC in dimension d(d − 2), having predictable symmetries and smaller equiangular tight frames embedded in them. We provide a recipe for how to calculate sets of vectors in dimension d(d − 2) that share these properties. They consist of maximally entangled vectors in certain subspaces defined by the numbers entering the d dimensional SIC. However, the construction contains free parameters and we have not proven that they can always be chosen so that one of these sets of vectors is a SIC. We give some worked examples that, we hope, may suggest to the reader how our construction can be improved. For simplicity we restrict ourselves to the case of odd dimensions.
Gamma-Ray Interaction of Selected Inorganic Scintillators Used in HEP Experiments
Authors: Dhillon Jasjot Singh , Vermani Yogesh K.
Published: April 2022

We attempted to study gamma-ray attenuation and sensing properties of conventional and modern inorganic scintillators being employed in the high energy physics (HEP) experiments. The mass attenuation coefficient (μm
), effective atomic number (Zeff
) and mean free path (mfp)were theoretically evaluated for the conventional scintillators materials such as CsI and NaI (Tl) and compared with advanced scintillator materials: PWO, PbF2, and BGO along with rare earth elements based scintillators such as LYSO:Ce, LuAG:Ce, BaF2:Y which have been proposed for applications in the future HEP experiments. Thegamma-ray attenuation parameters are analyzed within the framework of online software toolkit ‘py-MULBF’ over wide photon energy range from 0.015 MeV to 15 MeV.Variationof μm
(and, Zeff
) with photon energy follows a trend similar for most of the inorganic scintillator materialsinvestigated here.CsI, however, maintained almost same effective atomic number value with respect to photon energy which signifies that CsI may be suitable for specific gamma-ray detection and sensing applications. Lead-based scintillator materials such as PbF2, PWO along with high-Z BGO are observed to exhibit better radiation attenuation capabilities.
The Structural and Electrical Studies on Cu-Co Ferrites
Authors: Venkateshwarlu Ch , Ramesh M , Vinod G , Suresh Reddy Y , Rajashekhar K , Naresh B , Ramesh P , Dasharatha U , Venkatesh B , Laxman Naik J
Published: April 2022

The system Cobalt substituted copperferritesampleswere synthesized by a conventional double sintering ceramic method.A series of doped Copper ferrites withcomposithion Cu1-xCoxFe2O4 (x = 0.2, 0.4, and 0.6 ) are synthesized. The X-raydiffraction pattern at room temperature show that the sample exists in single phase with a spinel structure.Copper-Cobalt ferrites seriesaretakenand their electrical conductivityproperty are studied with a variation of composition and temperature. Log (σT) vs 103/T is almost linear with a variation close to the temperature of Curie.In general, the paramagnetic region activation energy is greater than that of the ferromagnetic region’s.
Influence of substrate temperature and laser wavelength on the structural, optical and electrical properties of laser ablated tin oxide thin films
Authors: K Harisha Kumar , Kumar Prasad , Dharmaprakash S M
Published: April 2022

The pulsed laser deposition (PLD) of tin oxide thin films on glass substrates has been achieved by ablating tin oxide (SnO2) pellet with Nd-YAG laser. The effects of laser wavelength (532nm, 1064nm) on the deposition as well as substrate temperature (room temperature, 250°C, 450°C) were investigated. The XRD studies were carried out and observed the growth of tetragonal rutile structure of SnO2 films. The FESEM micrographs show changes in surface morphology as a function of laser wavelength as well as the deposition temperature. The optical property investigations using UV-Vis spectra reveal an increase in the band gap with increasing temperature. The investigation of electrical properties using four-point probe method revealed the lower electrical resistivity of the SnO2 films. Thus, the as grown optimized SnO2 conducting thin film electrodes find its potential application in supercapacitor devices.
Physico-Chemical Key Parameters, Freundlich and Langmuir Isotherm, Rate Constant Studies on the Removal of Divalent Nickel using Delonix regia Fruit Pod as Low Cost Bioadsorbent
Authors: Mendiretta M M , Mudliar S L , Bharati A V
Published: April 2022

The exploitation of Delonix regia fruit pod (DRFP) as the low-cost biodsorbents is verified as an alternative for current pricey techniques for elimination of nickel ions from aqueous solutions. Batch adsorption studies is conducted to examine the effects of physico-chemical key parameters such as the initial metal ion concentration, pH, agitation time, stirring rate and adsorbent dosage on the adsorption from Delonix regia fruit pod (DRFP). The % adsorption, Langmuir constants, Freundlich constant for [Ni(II)] were determined for the adsorption system as a function of sorbate concentration. Equilibrium data were analyzed using the Langmuir and Freundlich isotherms whereas the adsorption kinetics data is also evaluated.
Fabrication of Janus Liquid marbles With Tunable Particle Coverage by Controlling the Surface Tension of the Core Liquid
Authors: Lekshmi Bindhu Sunil Kumar , Varanakkottu Subramanyan Namboodiri
Published: April 2022

Janus Liquid marbles (JLMs) are next-generation liquid marbles enwrapped with multi-particles of different sizes, hydrophobicity, and/or chemical properties. The functionally distinct surface of Janus Liquid marble enables the selective and precise manipulation of liquidmarble in a controllable manner. Here, we present an efficient method to tune the particle coverage of Janus Liquid marble by controlling the surface tension of the core liquid. The impact-based fabrication strategy is used for the continuous productionof JLMs of different volumes. The tunability in particle coverage is achieved for JLMs of volumein the range 5-10 μL. A simple energy balance analysis is employed for the theoretical estimation of the maximum spread parameter (βm) and found to be in reasonableagreement with the experimentally measured value.
Optically Controlled Liquid Marble Transport Platform
Authors: Ragisha Chetteente Meethal , Varanakkottu Subramanyan Namboodiri
Published: April 2022

Transport of liquid marbles is gaining significant attention owing to its application in various fields, including digital micro fluidics and drug delivery. Though various strategies exist for the transport of liquid marbles over the liquid substrates, on-demand transport over solid substrate remains an unexplored challenge. Most of the existing transport strategies rely on the properties of the droplet, limiting their applicability for specific liquids. Herein, we demonstrate an on-demand liquid marble transport platform based on local surface deformation of a polymer layer controlled by the thermal expansion of the confined air cavity. The platform is made of acrylic with a 5 mm hole, and a thin super hydrophobic polymer layer over it. To obtain maximum surface deformation, we have optimized the parameters such as hole diameter and thickness of the polymer layer. The hydrophobicity of the polymer layer is enhanced by coating the surface with Polyvinylidene difluoride (PVDF) nanoparticles for efficient liquid marble transport. We demonstrate the transport of liquid marble of volume 3 µL with a laser source (450 nm). A localized temperature rise of about 0.6 °C at the surface is sufficient to realize the transport of liquid marbles. The demonstrated strategy is simple and could be used for the on-demand transport of liquid marble, irrespective of the properties of the liquid.
Coulomb drag rate in a coupled electron-electron quantum wire system
Authors: Verma Vishal , Puttar Devi , Garg Vinayak , Moudgil R. K.
Published: April 2022

In this paper, we calculate the Coulomb drag rate in a coupled electron-electron (e-e) quantum wire system over a wide range of temperature T, and some selected values of electron number densityandinter-wire spacing. The intra- and inter-wire exchange-correlations are treated within the self-consistent mean-field approximation of Singwi et al (the so called STLS theory) suitably generalized to the coupled system at finite-T. At a fixed T, the drag rate is found to increase with decrease in inter-wire separation and/or electron number density due to increased intra- and inter-wire coupling among electrons. Further, we note that the magnitude of drag rate is more in the STLS theory as compared to the random-phase approximation (RPA), and the difference consistently increases with decrease in inter-wire spacing.
In-situ STS studies and first principles calculations on bare and Sn adsorbed UHV exfoliated WS2 layers
Authors: Mohan Manu , Kumar Singh Vipin , Ranjan Sahoo Mihir , S Reshmi , Roy Barman Sudipta , Bhattacharjee Kuntala
Published: April 2022

Abstarct. Two dimensional (2D) derivatives of tin (Sn) have obtained special deliberations recently due to practical realization of planar, as well as, buckled hexagonal lattice of Sn called stanene. However, it has been observed that proper choice of substrate is very important for growth of stanene like films owing to large core size of Sn that prefers sp
3 hybridization over sp
2. Transition metal dichalcogenides (TMDs) like MoS2 or WS2 with honey comb lattice structure seem to be promising substrate candidates for 2D growth of Sn. In the present work, we report mechanical exfoliation of few layers of WS2 under ultra-high vacuum (UHV) conditions and investigations of growth and local electronic structure by in-situ scanning tunneling microscopy (STM) and spectroscopy (STS) studies. Flat WS2 surface with honeycomb lattice structure in the atomic scale with a lattice constant of 0.34 nm is evident in the STM investigations, whereas, STS measurements reveal local density of states (LDOS) of WS2 with a bandgap of approximately 1.34 eV. Density functional theory (DFT) calculations performed by considering bulk WS2 reveal conduction and valence band states comprised of S p and W d at both sides of the Fermi energy (EF) and an indirect bandgap of 1.38 eV. Experimental observations upon Sn adsorption, reveal commensurate growth of Sn atoms on the sulfur `S’ sites with a buckling height of 40 ±10 pm. STS measurements exhibit local electronic structure of the Sn adsorbed surface with clear evidence of in-gap states. DFT calculations quantify the experimental results demonstrating `S’ sites as the most stable sites for the atomic adsorption of Sn with a buckling height of around 80 pm and reveal signature of in-gap hybridized states comprised of Sn p and W d orbitals.
Antibacterial Performance of Synthesised Superparamagnetic Fe3O4@TiO2 Nanoparticles
Authors: Kulkarni Sachin A , Sawadh P S , Chabukswar Anuruddha R. , Jagdale Swati
Published: April 2022

Co-precipitation method is used to prepare Fe3O4 nanoparticles, and its surface was coated with titania by sonication of ammonium sulphate. These nanoparticles were analyzed using SEM, UV-Vis, FTIR and antibacterial activity. The mono dispersion and increment in size with TiO2 concentration confirmed through SEM and good antibacterial activity is observed against gram positive and negative bacteria.
Quantitative analysis of rare earth elements in Mg–Zn–RE(Ce, Y, Gd)–Zr alloy
Authors: Li Yuguang , Guo Feng , Wang Yiwei , Cai Huisheng , Liu Liang
Published: April 2022

The solid solution amount of rare earth elements and the mass fraction of compounds were measured by low-temperature phase separation technology, the existing forms of rare earth elements in ZK-RE(Ce, Y, Gd) alloy were quantitatively studied, and the difference of solid solution ability of rare earth elements and the factors affecting the number of rare earth compounds were analyzed. The experimental results show that the solid solution amount of rare earth elements mainly depends on their addition amount, Zn and RE inhibit each other’s solid solution amount, and the order of solid solution amount (wt%) of rare earth elements with the same addition amount is GD > Y > Ce. Rare earth elements are mostly distributed in Mg–Zn–RE compounds, and the increase of rare earth content is helpful to form more Mg–Zn–RE compounds. With the same content of elements, the order of mass fraction of Mg–Zn–RE compounds is ZK-Ce system > ZK-Y system > ZK-Gd system. The order of solid solution ability of rare earth elements is Gd > Y > Ce, and the amount of solid solution directly affects the initial element content of compound precipitation in the remaining melt. The influence of Zn/Ce ratio in the residual melt of ZK-Ce alloy is shown in the number of rare earth compounds, while the Zn/Y(Gd) ratio in the residual melt of ZK-RE(Y, Gd) alloy determines the type and number of rare earth compounds.
Decreased isavuconazole trough concentrations in the treatment of invasive aspergillosis in an adult patient receiving extracorporeal membrane oxygenation support
Authors: Miller Michelle , Kludjian Geena , Mohrien Kerry , Morita Kazumi
Published: April 2022

Purpose

We present the case of a 56-year-old man with stage IV sarcoidosis on veno-venous extracorporeal membrane oxygenation (VV-ECMO) support for the management of respiratory failure receiving treatment with isavuconazole for invasive aspergillosis.

VV-ECMO is an increasingly utilized life support therapy for patients with cardiac and/or respiratory failure, but its impact on medication dosing is poorly understood. In our patient with invasive Aspergillus infection receiving VV-ECMO, because of difficulty achieving therapeutic serum concentrations of voriconazole, we administered isavuconazole 372 mg intravenously (IV) every 8 hours for 6 doses followed by 372 mg IV once daily. Isavuconazole has a favorable pharmacokinetic and safety profile compared to other azole antifungal agents, but its high protein binding and lipophilicity raise concerns about drug sequestration in the VV-ECMO circuit. To optimize the efficacy and safety of this treatment, the isavuconazole trough concentration was measured at days 5 and 17, at which time it was 1.7 and 0.7 μg/mL, respectively. The dose was subsequently increased to 744 mg IV once daily, and serum trough concentrations were measured 5 and 8 days after dose adjustment, corresponding to 3.7 and 2.9 μg/mL, respectively. To our knowledge, this is the third report to describe inadequate isavuconazole trough concentrations during VV-ECMO support when utilizing standard doses.

Conclusion

In the case described here, standard-dose isavuconazole (372 mg every 8 hours for 6 doses followed by 372 mg daily) did not achieve target trough concentrations in a patient receiving concomitant ECMO support.
A Comprehensive Strategy Based on UPLC-Q/TOF-MS for the Identification of Compounds in a Chinese Patent Medicine, Xiao’er Chiqiao Qingre Granules
Authors: Tian Gang , Gao Mengting , Li Chao , Shen Fei , Zhu Feng , Li Xin , Wang Yifei , Bao Beihua , Zhang Li , Huo Zongli , Yao Weifeng
Published: April 2022

The aim of this study was to establish a comprehensive strategy based on liquid chromatography coupled with mass spectrometry to potently identify as many compounds of Chinese patent medicine as possible. Ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) was used to qualitatively analyze the Chinese patent medicine Xiao’er Chiqiao Qingre Granules (XCQG), which is recorded in the Chinese Pharmacopoeia. A novel strategy, including targeted, semi-targeted and non-targeted identification, was built to explore the compounds based on accurate mass, characteristic fragments, retention time of standard substances, databases or literature. Based on the integrated identification, 250 compounds were identified in total, including 7 alcohols, 3 aldehydes, 17 alkaloids, 9 amino acids, 10 coumarins, 30 flavonoids, 29 glycosides, 12 ketones, 7 lignans, 20 organic acids, 12 phenols, 11 phenylpropanoids, 9 quinones, 3 steroids, 26 terpenes, 14 volatile oils and 31 other compounds. A novel strategy for the identification of compounds in traditional Chinese medicine (TCM) was developed with Ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS). It is also the first systematic study of compounds in XCQG, laying a foundation for further mechanism research of XCQG. More importantly, the strategy shows good application prospect in identifying compounds of TCM.
Pharmacokinetics and Safety of Bedaquiline in Human Immunodeficiency Virus (HIV)-Positive and Negative Older Children and Adolescents With Rifampicin-Resistant Tuberculosis
Authors: Hughes Jennifer A , Solans Belén P , Draper Heather R , Schaaf H Simon , Winckler Jana L , van der Laan Louvina , Radtke Kendra K , Fourie Barend , Wiesner Lubbe , Hesseling Anneke C , Savic Radojka M , Garcia-Prats Anthony J
Published: April 2022

Background

Pharmacokinetic data for bedaquiline in children are limited. We described the pharmacokinetics and safety of bedaquiline in South African children and adolescents receiving treatment for multidrug/rifampicin-resistant tuberculosis (MDR/RR-TB) in routine care.

Methods

In this observational cohort study, children aged 6–17 years receiving bedaquiline at recommended doses as part of MDR/RR-TB treatment underwent semi-intensive pharmacokinetic sampling. Bedaquiline and the M2 metabolite plasma concentrations were quantified, and nonlinear mixed-effects modeling performed. Pediatric data were described using a pre-established model of bedaquiline pharmacokinetics in adults. The exposure reference was 187 µg ⋅ h/mL, the median weekly area under the curve (AUC) of adults at week 24 of treatment with bedaquiline. Safety was assessed through monthly clinical, blood and electrocardiogram monitoring, and treatment outcomes described.

Results

Fifteen children (3 human immunodeficiency virus [HIV]-positive) with median age 13.3 years (range 6.5–16.3) were included. A bedaquiline pharmacokinetic model was adapted to be allometrically scaled in clearance and volume, centered in the median child population weight. Bedaquiline bioavailability was 57% of that in adults. Overall bedaquiline exposures were below target, and AUC reference attainment was achieved in only 3 (20%) children. Ten children experienced 27 adverse events at least possibly related to bedaquiline; no adverse events led to bedaquiline withdrawal. Two adverse events (arthritis and arthralgia) were considered severe, and 2 children had mild QT interval corrected for heart rate using Fridericia’s formula (QT) prolongation.

Conclusions

The evaluated doses of bedaquiline in children ≥ 6 years of age were safe but achieved slightly lower plasma concentrations compared to adults receiving the recommended dose, possibly due to delayed food intake relative to bedaquiline administration.
A Novel, Reverse Transcription, Droplet Digital PCR Assay for the Combined, Sensitive Detection of Severe Acute Respiratory Syndrome Coronavirus 2 with Swine Acute Diarrhea Syndrome Coronavirus
Authors: Zhang Zhou , Wang Na , Liu Xiaofei , Lv Jizhou , Jing Hongli , Yuan Xiangfen , Chen Dongjie , Lin Xiangmei , Wu Shaoqiang
Published: April 2022

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread over the world since its emergence. Although the dominant route of SARS-CoV-2 infection is respiratory, a number of studies revealed infection risk from contaminated surfaces and products, including porcine-derived food and other products. The SARS-CoV-2 outbreak has been severely threatening public health, and disrupting porcine products trade and the pig industry. Swine acute diarrhea syndrome coronavirus (SADS-CoV), which was responsible for large-scale, fatal disease in piglets, emerged in 2017 and has caused enormous economic losses in the pig industry. Currently, reverse transcription real-time PCR (RT-rPCR) is the gold standard method for SARS-CoV-2 diagnosis and is most commonly used for SADS-CoV detection. However, inaccurate detection of the SARS-CoV-2 infection obtained by RT-rPCR is increasingly reported, especially in specimens with low viral load.

Objective

This study aimed to develop an accurate reverse transcription droplet digital PCR (RT-ddPCR) assay for the detection of SARS-CoV-2 and SADS-CoV simultaneously.

Methods

Two pairs of primers and one double-quenched probe targeting the RNA-dependent RNA polymerase (RDRP) region of the open reading frame 1ab (ORF1ab) gene of SARS-CoV-2 and the corresponding ORF1ab region of SADS-CoV were designed to develop the RT-ddPCR assay. The sensitivity, specificity, repeatability, and reproducibility were tested using complementary RNAs (cRNAs) and clinical specimens.

Results

The detection limits of RT-ddPCR were 1.48 ± 0.18 and 1.38 ± 0.17 copies in a 20 μL reaction for SARS-CoV-2 and SADS-CoV cRNAs, respectively (n = 8), showing approximately 4- and 10-fold greater sensitivity than the RT-rPCR assay. This assay also exhibited good specificity, repeatability, and reproducibility.

Conclusion

The established RT-ddPCR assay was shown to be a highly effective, accurate, and reliable method for the sensitive detection of SARS-CoV-2 and SADS-CoV.

Highlights

This RT-ddPCR assay could be used to detect both SARS-CoV-2 and SADS-CoV in a sample with one double-quenched probe, and is also the first reported RT-ddPCR assay for SADS-CoV detection.
Stochastic sharing calculus for reasoning about social networks
Authors: Aman Bogdan , Ciobanu Gabriel
Published: April 2022

We study the dynamics of information sharing in web-based social networks and analyse in a stochastic manner some aspects of this phenomenon. We define the stochastic sharing calculus by considering probabilistic factors and stochastic evolutions that could be analysed statistically. A rate-based operational semantics allows specific observations and results regarding sharing in web-based social networks. To reason about the dynamics of the social networks, we verify statistically various aspects of information sharing expressed in CTL by employing an existing statistical model checker (after a translation of our processes into stochastic automata). Some queries related to the stochastic behaviours in social networks are illustrated by a running example.
High expression of the MADS-box geneVRT2increases the number of rudimentary basal spikelets in wheat
Authors: Backhaus Anna E , Lister Ashleigh , Tomkins Melissa , Adamski Nikolai M , Simmonds James , Macaulay Iain , Morris Richard J , Haerty Wilfried , Uauy Cristobal
Published: April 2022

Spikelets are the fundamental building blocks of Poaceae inflorescences, and their development and branching patterns determine the various inflorescence architectures and grain yield of grasses. In wheat (Triticum aestivum), the central spikelets produce the most and largest grains, while spikelet size gradually decreases acropetally and basipetally, giving rise to the characteristic lanceolate shape of wheat spikes. The acropetal gradient corresponds with the developmental age of spikelets; however, the basal spikelets are developed first, and the cause of their small size and rudimentary development is unclear. Here, we adapted G&T-seq, a low-input transcriptomics approach, to characterize gene expression profiles within spatial sections of individual spikes before and after the establishment of the lanceolate shape. We observed larger differences in gene expression profiles between the apical, central, and basal sections of a single spike than between any section belonging to consecutive developmental time points. We found that SHORT VEGETATIVE PHASE MADS-box transcription factors, including VEGETATIVE TO REPRODUCTIVE TRANSITION 2 (VRT-A2), are expressed highest in the basal section of the wheat spike and display the opposite expression gradient to flowering E-class SEPALLATA1 genes. Based on multi-year field trials and transgenic lines, we show that higher expression of VRT-A2 in the basal sections of the spike is associated with increased numbers of rudimentary basal spikelets. Our results, supported by computational modeling, suggest that the delayed transition of basal spikelets from vegetative to floral developmental programs results in the lanceolate shape of wheat spikes. This study highlights the value of spatially resolved transcriptomics to gain insights into developmental genetics pathways of grass inflorescences.
All-cause and cause-specific mortality in rheumatoid arthritis, psoriatic arthritis and axial spondyloarthritis: a nationwide registry study
Authors: Kerola Anne M , Kazemi Amirhossein , Rollefstad Silvia , Lillegraven Siri , Sexton Joseph , Wibetoe Grunde , Haavardsholm Espen A , Kvien Tore K , Semb Anne Grete
Published: April 2022

Objectives

To explore mortality and causes of death among Norwegian patients with RA, PsA and axial spondyloarthritis (axSpA) compared with the general population by conducting a nationwide registry-based cohort study.

Methods

Patients with RA, PsA and axSpA were identified from the Norwegian Patient Registry based on ICD-10 codes between 2008 and 2017. Using age as the time variable, all-cause and cause-specific mortality were estimated between 2010 and 2017 with the Kaplan–Meier estimator and the cumulative incidence competing risk method, respectively. Sex-, education level-, health region- and age group-adjusted hazard ratios (HRs) for mortality were estimated using Cox regression models.

Results

We identified 36 095 RA, 18 700 PsA and 16 524 axSpA patients (70%, 53% and 45% women, respectively). RA and axSpA were associated with increased all-cause mortality (HR 1.45 [95% CI: 1.41, 1.48] and HR 1.38 [95% CI: 1.28, 1.38], respectively). Women but not men with PsA had a slightly increased mortality rate (HR 1.10 [95% CI: 1.00, 1.21] among women and 1.02 [95% CI: 0.93, 1.11] among men). For all patient groups as well as for the general population, the three leading causes of death were cardiovascular diseases, neoplasms and respiratory diseases. RA patients had increased mortality from all of these causes, while axSpA patients had increased mortality from cardiovascular and respiratory diseases.

Conclusion

Even in the era of modern treatments for IJDs, patients with RA and axSpA still have shortened life expectancy. Our findings warrant further attention to the prevention and management of comorbidities.
Implications of sympathetic activation for objective versus self-reported daytime sleepiness in obstructive sleep apnea
Authors: Chen Baixin , Somers Virend K , Sun Qimeng , Dai Yanyuan , Li Yun
Published: April 2022

Study Objectives

Objective excessive daytime sleepiness (EDS) is associated with systemic inflammation and a higher risk of cardiometabolic morbidity in obstructive sleep apnea (OSA). We hypothesized that OSA with objective EDS is associated with higher levels of sympathetic nerve activity (SNA) when compared with self-reported EDS. We, therefore, examined the associations between objective and self-reported EDS with SNA in patients with OSA.

Methods

We studied 147 consecutive male patients with OSA from the institutional sleep clinic. Objective EDS and self-reported EDS were defined based on Multiple Sleep Latency Test (MSLT) latency ≤ 8 minutes and Epworth Sleepiness Scale (ESS) > 10, respectively. Twenty-four-hour urinary norepinephrine was used for assessing SNA. Blood pressure (BP) was measured both in the evening and in the morning.

Results

Twenty-four-hour urinary norepinephrine was significantly higher in patients with OSA with objective EDS compared with those without objective EDS (p = 0.034), whereas it was lower in patients with OSA with self-reported EDS compared with those without self-reported EDS (p = 0.038) after adjusting for confounders. Differences in the sympathetic drive were most striking in those with an objective but not self-reported EDS versus those with self-reported but not objective EDS (p = 0.002). Moreover, shorter MSLT latency was significantly associated with higher diastolic BP (β = −0.156, p = 0.049) but not systolic BP. No significant association between ESS scores and BP was observed.

Conclusions

Objective, but not self-reported EDS, is associated with increased SNA and diastolic BP among males with OSA, suggesting that objective EDS is a more severe phenotype of OSA that is accompanied by higher sympathetic drive, higher BP, and possibly greater cardiovascular morbidity and mortality.