bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimentally validated model of a self-switched solar motor for pumping application
Authors: Mseddi Amina , Aloui Helmi , Vido Lionel , Coty Alain
Published: January 2021

This paper presents an original and autonomous solar pumping system, based on a Switched Reluctance Motor commutated by photovoltaic cells (SRMPV) and powered by a photovoltaic generator. In this work, experimental tests characterizing the SRMPV are presented. Based on these experiments, the first mathematical model of this complex system is developed and implemented under the Matlab-Simulink platform. In order to optimize the design of the SRMPV, the simulation platform is used to perform a sensitivity study. This research will focus on the determination of the optimal number of coils, the optimal air gap, and the optimal winding cross area of the switched reluctance motor.
Label-free fluorescence aptasensor based on AuNPs and CQDs for the detection of ATP
Authors: Ren Linjiao , Xu Peng , Zhang Pei , Qin Zirui , Zhang Yintang , Jiang Liying
Published: January 2021

A label-free fluorescence aptasensor was studied for adenosine triphosphate (ATP) detection that combines low biosensor toxicity with a simplified preparation process. In this study, the aptamer of the gold nanoparticle@aptamer@carbon quantum dot nanostructure could specifically identify ATP, resulting in the change of the fluorescence signal. In order to analyze the performance of the sensor, the effects of the carbon quantum dot (CQD) concentration and centrifugal rate on the stability of the probe were investigated. The results show that the sensor was superior under the 220 µl CQD volume and 2000 rpm centrifugal rate. Furthermore, the linear relationship between the change of the fluorescence signal and ATP concentration is Y = 359.747 + 0.226X within the volume range of 20 µM–280 µM. The correlation coefficient is 0.98, and the detection limit is 20 µM. No obvious fluorescence change was observed in solutions containing other common ions. On the basis of no pollution and simplicity, this sensor demonstrates great potential as a low-cost diagnostic tool for the detection of various targets, particularly for use in the fields of food safety and biomedical diagnostics.
Coherent power scaling in photonic crystal surface emitting laser arrays
Authors: King Ben C. , Rae Katherine J. , McKenzie Adam F. , Boldin Aleksandr , Kim Daehyun , Gerrard Neil D. , Li Guangrui , Nishi Kenichi , Takemasa Keizo , Sugawara Mitsuru , Taylor Richard J. E. , Childs David T. D. , Hogg Richard A.
Published: January 2021

A key benefit of photonic crystal surface emitting lasers (PCSELs) is the ability to increase output power through scaling the emission area while maintaining high quality single mode emission, allowing them to close the brightness gap which exists between semiconductor lasers and gas and fiber lasers. However, there are practical limits to the size, and hence power, of an individual PCSEL device, and there are trade-offs between single-mode stability and parasitic in-plane losses with increasing device size. In this paper, we discuss 2D coherent arrays as an approach to area and coherent power scaling of PCSELs. We demonstrate in two and three element PCSEL arrays an increase in the differential efficiency of the system due to a reduction in in-plane loss.
Interface characterization of Al2O3/m-plane GaN structure
Authors: Kaneki Shota , Hashizume Tamotsu
Published: January 2021

The interface properties of Al2O3/GaN structures fabricated on the homo-epitaxial m-plane GaN were investigated. An atomically flat surface with a root mean square roughness of 0.15 nm was observed for the m-plane GaN layer on a substrate inclined 5° toward the [000-1] direction. Even for the as-prepared sample, we obtained relatively low state densities of less than 3 × 1011 cm−2 eV−1 at the Al2O3/m-plane GaN interface. A possible mechanism for such low interface state densities was discussed in correlation with the Ga–N dimer on the m-plane GaN surface. The post-metallization annealing process at 300 °C realized excellent capacitance–voltage (C–V) characteristics without frequency dispersion, further lowering state densities to 1.0 × 1010 cm−2 eV−1–2.0 × 1010 cm−2 eV−1. In addition, the present Al2O3/m-plane GaN diode showed stable interface properties at high temperatures. Neither the flatband-voltage shift nor the frequency dispersion was observed in the C–V characteristics measured at 200 °C. Furthermore, current–voltage characteristics with relatively low leakage current in the order of 10−9 A/cm2 remained almost unchanged at temperatures up to 200 °C.
Multiple stopbands and wavefield asymmetry of surface water waves in non-Bragg structures
Authors: Kundu Joshua-Masinde , Liu Ting , Tao Jia , Zhang Jia-Yi , Fan Ya-Xian , Tao Zhi-Yong
Published: January 2021

In this paper, we use laboratory wave tank experiments to study the effect of asymmetry and defects on the bandgaps of surface water waves and use the finite element numerical method to validate our results. We demonstrate here that breaking the mirror symmetry around the midplane of a periodic structure introduces multiple bandgaps in the spectrum caused by the involvement of high-order transverse modes. The results show that the presence of a defect in the structure leads to the formation of a strong defect mode in the Bragg gap, which is localized around the defect element and a weak mode in the induced non-Bragg gap. The results show that the bandgap excited by symmetry breaking is much narrower due to the weak mode coupling. In addition, at the non-Bragg resonance frequency in the defect state, the transverse water surface wavefield distribution around the defect is asymmetric about the midplane of the channel. The multiple transmission modes in the spectrum of the structure can be applied in the design of Bragg reflection-based wave attenuation structures that can help protect shorelines and coastal infrastructure. The asymmetry of the surface wavefield in the non-Bragg gap can be applied in the development of energy harvesting technologies. Due to the generality of wave phenomena in periodic structures, the findings of this research provide a basis for more research in physical acoustics and optics and may lead to the development of cutting-edge appliances, such as bandpass filters.
Fluorescence manipulation from graphene and hydrogen-terminated graphene covered Au nanoparticles
Authors: Guo Xitao , Luo Xiaoguang , Zafar Amina , Tan Yonghao , Wang Zhidong
Published: January 2021

This paper presents the fluorescence manipulation of Rhodamine-6G (R6G) due to Au nanoparticles (Au-NPs) covered by pristine graphene and hydrogen-terminated graphene. By taking florescence signals of R6G on a quartz substrate as the standard reference, we observe an ∼fourfold increase in fluorescence intensity of R6G on bare Au-NPs deposited on the quartz substrate. However, this enhancement reduces to ∼1.8-fold when Au-NPs are covered by H-terminated graphene. In the case of Au-NPs covered by pristine graphene, the fluorescence of R6G is significantly quenched by a factor of ∼7.6-fold. The resulting fluorescence level can be attributed to the local field enhancement from Au-NPs and the quenching effect of graphene in the Au–graphene hybrid nanostructure, which are confirmed by our controlled experimental and simulation results. Our work reveals that the surface modification of metal NPs by graphene materials would bring a great impact on fluorescence, providing a simple approach for artificially manipulating fluorescence for specific molecular sensing, detecting, and imaging.
A comparison of different numerical schemes in spherical Couette flow simulation
Authors: Abbas Suhail , Shah Abdullah , Hussain Zahid , Hussain Shahid
Published: January 2021

We compare the performance of line Gauss–Seidel (LGS), point Gauss–Seidel (PGS), and alternating direction implicit (ADI) linear solvers used in the artificial compressibility method for the numerical solution of the three-dimensional incompressible Navier–Stokes equations. Spatial discretization is carried out using a fifth-order WENO scheme for the convective terms and a second-order central difference scheme for the viscous terms. A comparison is made by simulating the spherical Couette flow problem, with only the inner sphere rotating and the outer one fixed. OpenMP is used for numerical computation in parallel for the three schemes. First, we compare the numerical efficiency of the solvers by computing 0-vortex flow for a medium-gap σ=R2−R1/R1=0.25. Second, we make a residual comparison for a steady-state flow calculation based on the CFL number and artificial compressibility factor. Finally, we compare the three solvers for unsteady flow computations based on the artificial compressibility factor. The results show that the LGS solver is more reliable than the PGS and the ADI solvers. To show the accuracy of the LGS scheme, we compute different flow modes for an intermediate-gap clearance ratio σ=R2−R1/R1=0.14. The computed results have good agreement with the existing numerical results.
Numerical simulation of tire steering on sandy soil based on discrete element method
Authors: Hu Cheng , Gao Jingwei , Diao Jincheng , Song Xiaobo
Published: January 2021

The steering performance of off-road tires on sandy soil has a great influence on the maneuverability of the vehicle, which has long been studied by scholars. However, the discrete element method (DEM) modeling of tire steering on sand is still lacking. In this paper, an off-road tire steering model on sandy soil is established by using the discrete element method, and the parameters of the sandy soil model are calibrated based on the triaxial compression test and inclined plate experiment. Then, the parameters of the sandy soil model are verified by the reduced-scale single wheel soil bin test under a straight-driving condition. Finally, the influence of the steering radius, roll angle, roll angle, and slip rate on the tire steering process is studied. The results show that a reduction in the steering radius has a slight influence on the drawbar pull and driving torque but a greater influence on the growth of the lateral force, the aligning torque, and the reduction in sinkage. The slip rate and sideslip angle play an important role in drawbar pull, drive torque, lateral force, and torque. The roll angle has a small influence on the drawbar pull and driving torque but a greater influence on the lateral force and the aligning torque.
How do neuroglial cells respond to ultrasound induced cavitation?
Authors: Wrede Alex H. , Luo Jie , Montazami Reza , Kanthasamy Anumantha , Hashemi Nicole N.
Published: January 2021

Reactive astrocytes are known to play a vital role in the overall response of the brain during a traumatic brain injury (TBI). Modern studies have speculated the existence of cavitation in the skull during a TBI, which has alarming potential to cause detrimental damage. Previous studies have confirmed the upregulation of various harmful genes in neurodegenerative diseases. Studying the longitudinal presence of these harmful genes in response to cavitation allows for optimized understanding of and treatment methods for cavitation exposure. We seek to characterize the longitudinal genetic expression levels that astrocytes exhibit after exposure to cavitation and further elucidate the startling presence of cranial cavitation. We have designed a system to induce cavitation on targeted microbubbles. Astrocytic expression levels of various common genes, like TNFα, IL-1β, and NOS1, that have been documented in TBI studies are our target of interest. Results summarize specific gene trends from 1 h to 48 h after cavitation. Our data conclude that maximum expression is not consistently exhibited immediately after cavitation exposure and most genes have individualized genetic trends. IL-1β shows a decreasing expression over 48 h, and TNFα shows upregulation until the 6 h time point but then begins to decrease in expression. The upregulation of NOS1 has been documented in neurodegenerative diseases, like Alzheimer’s and Parkinson’s disease. This study has shown a consistent upregulation in NOS1 expression from 0 h to 48 h. These results postulate a possible linkage between cavitation damage and neurodegenerative diseases. This analysis also provides novelty in optimizing treatments for the astrocytic function after TBI and legitimizing the concern of cranial cavitation existence.
Boundary layer stagnation point flow of the Casson hybrid nanofluid over an unsteady stretching surface
Authors: Alghamdi Wajdi , Gul Taza , Nullah Mehranullah , Rehman Ali , Nasir S. , Saeed A. , Bonyah E.
Published: January 2021

This work examines the behavior of hybrid nanofluid flow toward a stagnation point on a stretching surface. Copper and aluminum are considered as the hybrid nanoparticles. The Casson (non-Newtonian) fluid model is considered for hybrid nanofluids applying magnetic effects perpendicular to the surface. The governing equations are reduced to the ordinary differential equations using similarity transformations. The resulting equations are programmed in the Mathematica software using the OHAM-BVPh 2.0 package. The most important results of this investigation are the effects of different physical parameters such as β, M, S, and Pr on the velocity profile, temperature profile, skin friction coefficient, and local Nusselt number. With the escalation of the magnitude of the Prandtl number Pr, the temperature profile slashes down, while with the variation of the Eckert number, the temperature field improves. The key outcomes specify that the hybrid Casson nanofluid has a larger thermal conductivity when equated with traditional fluids. Therefore, the hybrid fluid plays an important role in the enhancement of the heat phenomena. The ratification of our findings is also addressed via tables and attained noteworthy results.
Depth profiling of 3D skyrmion lattices in a chiral magnet—A story with a twist
Authors: van der Laan G. , Zhang S. L. , Hesjedal T.
Published: January 2021

From the perspective of surface science, only the topmost atomic layers usually exhibit physical properties that are different to those of the bulk material, whereas the deeper layers are assumed to be bulk-like and remain largely unexplored. Going beyond conventional diffraction and imaging techniques, we have determined the depth dependence of the full 3D spin structure of magnetic skyrmions below the surface of a bulk Cu2OSeO3 sample using the polarization dependence of resonant elastic x-ray scattering (REXS). While the bulk spin configuration showed the anticipated Bloch type structure, it was found that the skyrmion lattice changes to a Néel twisting (i.e., with a different helicity angle) at the surface within a distance of several hundred nm. The exact surface helicity angle and penetration length of this twist have been determined, revealing the detailed internal structure of the skyrmion tube. It was found that the experimental penetration length of the Néel twisting is 7× longer than the theoretical value given by the ratio of J/D. This indicates that apart from the considered spin interactions, i.e., the Heisenberg exchange interaction J and the Dzyaloshinskii-Moriya interaction D, as well as the Zeeman interaction, other effects must play an important role. The findings suggest that the surface reconstruction of the skyrmion lattice is a universal phenomenon, stemming from the breaking of translational symmetry at the interface.
Weak magnetic anomaly signal detection based on the entropy of mixed differential signal
Authors: Wang Z. , Qiu J. , Xie D. , Ou J. , Xu Q.
Published: January 2021

Magnetic anomaly detection is of great significance in geological exploration and underwater target detection. However, the magnetic anomaly signal is not easy to be detected because of its weakness relative to the magnetic environmental noise, and the detection probability of the magnetic anomaly signal is affected by signal frequency. We propose a mixed differential minimum entropy method which can detect the weak magnetic anomaly signal. The proposed method combines the coherence difference method with the synchronous reference subtraction method in preprocess, which can suppress common-mode noise in the signal and relax the limitation of the frequency of the magnetic anomaly signal on the detection ability. Using the concept of entropy to describe the preprocessed signal can eliminate the residual high-frequency noise and further improve the signal-to-noise ratio of the target signal. Results show that the proposed method may effectively improve the signal-to-noise ratio and increase the frequency range of the magnetic anomaly signal, which has better detection performance than that of traditional method.
Effect of the Y element on the structural, electronic and magnetic properties of Heusler compounds Co2YIn (Y = V, Nb, and Ti): An ab initio study
Authors: Muthui Zipporah , Musembi Robinson , Mwabora Julius , Kashyap Arti
Published: January 2021

We report the effect of varying the Y element on the structural, electronic and magnetic properties of Co2YIn (Y = V, Nb, Ti) Heusler compounds using Density Functional Theory (DFT). The effect of the lattice parameter and total number of valence electrons on spin polarization and the magnetic properties of these Heusler compounds is compared. Co2VIn and Co2NbIn have the same number of valence electrons as Nb and V are from the same group in the periodic table. Co2VIn has almost the same lattice constant as Co2TiIn but they differ in the total number of valence electrons by one, as Ti and V are next neighbors in the same period of the periodic table. The optimized lattice parameters for Co2NbIn and Co2TiIn are found to be 6.20 Å and 6.05 Å respectively, while that of Co2VIn has been reported to be 6.00 Å. Co2NbIn is half metallic with an energy band gap of 0.1 eV in the minority states and has total magnetic moments of 2.02 µB/f.u. very close to the 2.00 µB/f.u. predicted by the Slater-Pauling rule, while Co2TiIn is not half metallic but has a highly spin polarized electronic structure having a spin polarization of 89.59% and total magnetic moments of 1.04µB/f.u. While reducing the number of the valence electrons by one in Co2TiIn has a significant effect on the magnetic moments and spin polarization, an increase in the lattice parameter while maintaining the same number of valence electrons in Co2NbIn does not result in the destruction of the half metallic gap.
Coexistence of magnetism and superconductivity in the iron containing FeSr2YCu2O7.57 cuprate as studied by μSR
Authors: López-Paz Sara A. , Sari D. P. , Hillier A. D. , Alario-Franco M. A.
Published: January 2021

Substitution of copper by iron in the charge reservoir block of the YSr2Cu3O6+δ (YSCO) cuprate superconductor brings out an appealing insight on the interplay between superconductivity and magnetism. In the resulting FeSr2YCu2O7+δ (Fe-1212) materials, FeO1+δ layers and CuO2 bi-layers are alternated along the stacking direction, in close analogy to the RuSr2GdCu2O8 (Ru-1212) ferromagnetic superconductor. For the FeSr2YCu2O7.57 compound, both BVS calculations and spectroscopic data reflect a high doping level in the superconducting planes of pCuO2 ∼ 0.30, placing this cuprate on the overdoped region of the conventional phase diagram for cuprate superconductors. Nonetheless, iron cations in the charge reservoir block (CRB) are quite oxidized, reaching a high formal oxidation state of Fe3.6+. This highly doped FeSr2YCu2O7.57 cuprate is superconducting below Tc = 30 K and, from our muon spin relaxation spectroscopy (μSR) study, the presence of magnetic interactions has been substantiated. Most interestingly, the coincidence of the onset of the magnetic interactions with the superconducting critical temperature suggests a complex interplay between magnetism and superconductivity in this overdoped cuprate.
Structural and magnetic properties of iodide-mediated chemically synthesized L12 FePt3 nanoparticles
Authors: Deepchand Vimal , Tzitzios Vasileios , Hadjipanayis George C.
Published: January 2021

In this work, we study the effect of elemental iodine as a halide intermediary in the synthesis of FePt3 nanoparticles using a co-reduction of Fe(acac)3 and (NH4)2PtCl2 with 1,2-hexadecanediol. Our study shows that elemental iodine facilitates the formation of FePt3 nanoparticles with the L12 structure. When iodine is not used, the as-made nanoparticles have mostly the disordered fcc FePt3 structure. The as-made nanoparticles are ferromagnetic and have a Curie temperature close to 380 K. Annealing of the as-made nanoparticles leads to an increased particle size and a transformation to the ordered L12 FePt3 phase. Nanoparticles annealed at 700°C for 30 minutes show a mixture of two magnetic phases, a ferromagnetic phase with a lower ordering temperature of ∼300 K and an antiferromagnetic phase with a Néel temperature around 135 K.
Separate quantitative evaluation of degree of order and perpendicular magnetic anisotropy for disorder and order portion in FePt granular films
Authors: Saito Takashi , Tham Kim Kong , Kushibiki Ryosuke , Ogawa Tomoyuki , Saito Shin
Published: January 2021

The dependence of the degree of order and perpendicular magnetic anisotropy (Ku⊥) on magnetic layer thickness (dmag) for FePt granular films with various grain boundary materials (GBMs) were investigated. According to the analysis for granular films with a constant GBM volume of 30 vol%, the order, disorder, and non-epitaxial portions co-existed in the FePt granular films. From the separate quantitative evaluation for these portions, the following was found; 1) the degree of order and magnitudes of Ku⊥ for disorder and order portions against dmag were constant, while the film average evaluation resulted in the dependence of the degree of order and Ku⊥ on dmag and the positive correlation between the grain diameter and the degree of order, 2) for the order portion, Ku⊥ had linear correlation with the degree of order, 3) the magnitude of Ku⊥ and the degree of order for the order portion depended on GBM.
Magnetic and structural properties of MnXNiSn (X = Mn, Fe, Co)
Authors: Khatri Yogesh , Skomski Ralph , Zhang Wenyong , Valloppilly Shah R. , Sellmyer David J. , Kashyap Arti
Published: January 2021

Crystal structure and magnetic properties of Heusler alloys MnXNiSn (X = Mn, Fe, Co) are investigated using density functional theory and compared with experimental results. The parent alloy Mn2NiSn, which crystallizes in the inverse Heusler structure, is found to be ferrimagnetic, in agreement with previous experimental and theoretical work. The Fe and Co substitutions cause the alloys to assume a fairly well-ordered Y structure and enhance the magnetization substantially. We find that the strong nearest neighbour Mn-X exchange changes from antiferromagnetic (X = Mn) to ferromagnetic (X = Fe, Co), which explains and actually overestimates the experimental changes. A striking feature of the system is that Fe and Co have opposite effects on the Curie temperature Tc: they reduce and enhance Tc, respectively. We qualitatively explain this behaviour in terms of two-sublattice model based on the nearest-neighbour exchange.
On the synthesis, structural transformation and magnetocaloric behavior of Ni37.5Co12.5Mn35Ti15 melt-spun ribbons
Authors: López-Cruz M. , Zamora J. , Sánchez-Valdés C. F. , Sánchez Llamazares J. L.
Published: January 2021

We fabricated Ni37.5Co12.5Mn35Ti15 melt-spun ribbons at linear wheel speeds (WS) of 20 and 8 ms-1 (series A and B, respectively). The effect of a short time thermal annealing (30 min.) between 1023 K and 1173 K on the martensitic-like structural transition and the crystal structure, microstructure and magnetic entropy change ΔSM(T) curves and related parameters for as-solidified (AS) samples of series A were studied. Whereas the Curie temperature of austenite (AST) TCA keeps nearly constant, both the reduction of the solidification rate and the increase on the thermal annealing temperature increase the temperature of the structural transformation reducing the magnetization change across the AST to martensite (MST) transition. The martensitic transformation (MT) in AS samples undergoes from a B2-type ferromagnetic (FM) AST with TCA = 328 K to a monoclinic martensite (MST); SEM images evidenced a partially grain-oriented microstructure formed by columnar in shape-elongated grains with their major axis oriented along the thermal gradient during solidification. Magneto-structural transition for AS ribbons of series A occurs in the vicinity of room temperature and is accompanied by a magnetization change of around 63 Am2kg-1. For a magnetic field change of 2 T these samples showed a maximum magnetic entropy change |ΔSM|max of 13.8 (9.5) J kg-1 K-1 for the MST→AST (AST→MST) transformation. This is below the previously reported for this alloy composition (27.2 J kg-1 K-1), and is related to the broader magneto-structural transition.
Magnetic properties and magnetocaloric effect in Dy100-xYx solid solutions
Authors: Taskaev Sergey , Khovaylo Vladimir , Ulyanov Maxim , Bataev Dmitriy , Basharova Anastasiya , Kononova Marina , Plakhotskiy Daniil , Bogush Mikhail , Zherebtsov Dmitriy , Hu Zhang
Published: January 2021

Dysprosium possesses the highest magnetic moment among the rare-earth elements and undergoes a second-order magnetic phase transition to a complex helical antiferromagnetic ordering at Néel temperature TN = 180 K which is followed by a transformation to the ferromagnetic ordering at a lower temperature. Superior magnetic properties and tunability of the magnetic phase transition temperatures make Dy and its solid solutions perspective for the use in technology of magnetic refrigeration at cryogenic temperatures, specifically for the liquefaction of natural gases. In this work we report on the evolution of magnetic properties in solid solutions of Dy100-xYx (x = 0 – 15). It was found that the dilution of Dy magnetic subsystem by a non-magnetic Y has rather a weak impact on the magnetization saturation, which decreases from Ms ∼280 A⋅m2/kg in the x = 0 sample to Ms ∼259 A⋅m2/kg in the x = 15 sample. As a consequence, the isothermal magnetic entropy change was found to decrease slightly in the series of Dy100-xYx (x = 0 – 15) solid solutions.
A new way to determine the magneto-crystalline anisotropy of Li-Ti-Mn-Zn ferrites
Authors: Saied J. , Lebourgeois R. , Laur V.
Published: January 2021

The knowledge of the magnetocrystalline anisotropy is often essential and its determination remains an ambitious challenge. In this article, we propose a new way to measure the anisotropy magnetic field of some substituted lithium ferrites. To achieve that, we have measured the complex permeability versus frequency of several substituted lithium-based ferrites, in which, the anisotropy field is related to the gyromagnetic resonance frequency. However, the gyromagnetic resonance frequency is hidden by the domain wall motion resonance. To solve the problem, we have sintered the ferrite at different temperatures to control the microstructure of the ferrite, thus separating the magnetization mechanisms. We have obtained results of anisotropy fields comparable to those of the literature between 270 and 460 Oe.
Hearing in individuals enrolled for drug-resistant tuberculosis treatment
Authors: Shastri Usha , Khateeb Zaiba Fatima , Khan Mohd Aaman , Kanagokar Vibha
Published: January 2021

Purpose

Some of the anti-tuberculosis (TB) drugs used for drug-resistant tuberculosis (DR-TB) are ototoxic and can result in hearing loss with extended use. Hearing loss can be present in individuals with DR-TB even before the initiation of anti-TB treatment. Not all studies investigating the adverse drug reactions of DR-TB treatment performed standard audiometric tests on their participants. Thus, the pre-treatment hearing status of individuals with DR-TB is less documented. We aimed to retrospectively profile hearing status in individuals diagnosed with DR-TB before initiation of anti-TB medication.

Method

Retrospective analysis of pre-treatment audiological reports from 110 individuals (81 males) aged between 18 and 82 years diagnosed with DR-TB from August 2017 to August 2018 who reported to a tertiary care hospital in Mangaluru, Karnataka, a South Indian city was done. Case history and pure tone audiometry data were available for all individuals. Descriptive statistics for each parameter were considered and the Chi-square test of independence was performed between selected variables to check for any association between variables.

Results

Only 29.09% (n = 32) of the individuals reported ear and hearing-related complaints. Pre-treatment for DR-TB, 88 individuals (80%) had some degree of hearing loss in at least one ear. Mild degree (60.4%) and sensorineural type (55.68%) of hearing loss were most frequently observed. Greater hearing loss was noted at high frequencies than at low frequencies. A significant association between age and prevalence of hearing loss was found [χ
2(2, N = 110)=10.28, p < .05]. There was no significant association between age and degree of hearing loss [χ
2(8, N = 87)=4.46, p > .05] as well as age and the type of hearing loss [χ
2(4, N = 87)=4.29, p > .05].

Conclusion

High prevalence of hearing loss in individuals with DR-TB before initiation of anti-TB treatment was observed. However, very few individuals reported reduced hearing during case history. We emphasise performing standard audiometric tests as recommended by the World Health Organisation (WHO) to monitor the effects of ototoxicity in individuals undergoing treatment for DR-TB rather than depending on self-reported measures of change in hearing or clinician determined need for hearing tests.
Quality assurance for the use of computational methods in dosimetry: activities of EURADOS Working Group 6 ‘Computational Dosimetry’
Authors: Rabus H , Gómez-Ros J M , Villagrasa C , Eakins J , Vrba T , Blideanu V , Zankl M , Tanner R , Struelens L , Brkić H , Domingo C , Baiocco G , Caccia B , Huet C , Ferrari P
Published: January 2021

Working Group (WG) 6 ‘Computational Dosimetry’ of the European Radiation Dosimetry Group promotes good practice in the application of computational methods for radiation dosimetry in radiation protection and the medical use of ionising radiation. Its cross-sectional activities within the association cover a large range of current topics in radiation dosimetry, including more fundamental studies of radiation effects in complex systems. In addition, WG 6 also performs scientific research and development as well as knowledge transfer activities, such as training courses. Monte Carlo techniques, including the use of anthropomorphic and other numerical phantoms based on voxelised geometrical models, play a strong part in the activities pursued in WG 6. However, other aspects and techniques, such as neutron spectra unfolding, have an important role as well. A number of intercomparison exercises have been carried out in the past to provide information on the accuracy with which computational methods are applied and whether best practice is being followed. Within the exercises that are still ongoing, the focus has changed towards assessing the uncertainty that can be achieved with these computational methods. Furthermore, the future strategy of WG 6 also includes an extension of the scope toward experimental benchmark activities and evaluation of cross-sections and algorithms, with the vision of establishing a gold standard for Monte Carlo methods used in medical and radiobiological applications.
On Langmuir oscillations breaking driven by ion motion and relativistic effects
Authors: Pramanik Sourav , Maity Chandan
Published: January 2021

The nonlinear evolution of Langmuir oscillations (LOs) is studied in a cold plasma including the ion motion and (weakly) relativistic mass variation of electrons. For the purposes, a simple perturbation technique is used to solve the governing one-dimensional fluid-Maxwell’s equations. The solutions show that the Langmuir mode frequency acquires spatial dependencies due to the finite ion inertia and relativistic effects. As a result, excited LOs mix up in phase and break at arbitrarily low amplitudes. An approximate expression for the phase-mixing time of LOs is then obtained, thus improving some earlier results. Phase-mixing time is found to decrease with the increase of both the electron-to-ion mass ratio parameter and relativistic factor. A comparative analysis between these two effects is also carried out to clarify which effect contributes more to the phase-mixing time. It is revealed that phase-mixing is induced more quickly due to the ion motion than the relativistic effects.
Effect of resonant magnetic perturbations with plasma response on particle orbit characters
Authors: Su Chunyan , Chen Shaoyong , Mou Maolin , Guo Wenping , Chen Xieyu , Tang Changjian
Published: January 2021

The ion orbits considering the resonant magnetic perturbation (RMP) fields with plasma response are studied numerically using the full orbit code based on HL-2A tokamak parameters. The results show that RMP with plasma response can cause a more significant radial orbit expansion than the vacuum RMP field. Further study exhibits that the physical mechanism of the orbit expansion relates to the resonant field amplification (RFA) effect. The passing orbits expansion become quite large when ions pass through the region where the perturbed field is strongly amplified. Meanwhile, the trapped orbits expansion is determined by the average value of the perturbed field where corressponding orbit goes by. This indicates that the plasma response to RMP plays an important role in changing the characteristics of ion orbits, which can lead to a redistribution of fast ions and thus providing a possible mechanism for the degradation of plasma confinements in experiments.
A method for estimating masses ofWUrsaeMajoris-type binaries
Authors: Lu Li-Na , Liu Jin-Zhong , Jiang Deng-Kai , Wang Ya-Hui
Published: January 2021

Masses of W Ursae Majoris-type (W UMa) binaries play a critical role in investigating stellar dynamical evolutionary status. In this paper, we combine the PARSEC (PAdova and TRieste Stellar Evolution Code) with the Roche geometric model to provide a method to determine the masses of W UMa systems. To verify the validity of this method, we compile a sample of 140 spectrum binaries from the literature, which includes 76 W- and 64 A-subtype systems with reliable physical parameters. We find that the average fractional difference and the standard deviation (σM) of the residuals for W-subtype and A-subtype approximately amount to 15.66% and 0.1218, 16.03% and 0.2094, respectively. Meanwhile, we also perform detailed analyses in accordance with the orbital period, the effective temperatures and the mass ratio. We find that the method is more applicable to determine masses for W UMa systems with low effective temperature and short period.
The formation of a blue cluster in the local Universe
Authors: Wen Qing-Xin , Luo Yu , Kang Xi
Published: January 2021

It is well known from the Butcher-Oemler effect that galaxies in dense environment are mostly red with little star formation and the fraction of blue galaxies in galaxy groups/clusters also declines rapidly with redshifts. A recent work by Hashimoto et al. reported a local ‘blue cluster’ with a high fraction of blue galaxies (∼ 0.57), higher than the model predictions. They ascribed this blue cluster to the feeding of gas along a filamentary structure around the cluster. In this work we use group catalog from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) and the state-of-art of semi-analytic model (SAM) to investigate the formation of blue clusters in the local Universe. In total, we find four blue clusters with halo mass ∼1014
M
⊙ at 0.02 < z < 0.082, while only the one found by Hashimoto et al. is in a filamentary structure. The SAM predicts that blue clusters have later formation time and most blue satellite galaxies are recently accreted. We conclude that the formation of blue clusters is mainly governed by newly accreted blue satellites, rather than the effect of large-scale environment.
Active Brownian particle in harmonic trap: exact computation of moments, and re-entrant transition
Authors: Chaudhuri Debasish , Dhar Abhishek
Published: January 2021

We consider an active Brownian particle in a d-dimensional harmonic trap, in the presence of translational diffusion. While the Fokker–Planck equation cannot in general be solved to obtain a closed form solution of the joint distribution of positions and orientations, as we show, it can be utilized to evaluate the exact time dependence of all moments, using a Laplace transform approach. We present an explicit calculation of several such moments at arbitrary times and their evolution to the steady state. In particular we compute the kurtosis of the displacement, a quantity which clearly shows the difference of the active steady state properties from the equilibrium Gaussian form. We find that it increases with activity to asymptotic saturation, but varies non-monotonically with the trap-stiffness, thereby capturing recently observed active-to-passive re-entrant behavior.
A computer system for the leukocytes classification in medical images
Authors: Chernykh E M , Mikhelev V M
Published: January 2021

The paper is about the development of a computer system for the white blood cells images classification. Solving the leukocytes classification task makes it possible to diagnose not only the blood diseases, but also a wide range of other diseases, as well as to evaluate the overall state of a person’s health. Modern leukocytes classification methods have a fairly large number of shortcomings, which make a problem of finding the most effective method as a tool to solve this task. In our computer system we use the method based on using a trained convolutional neural network as a binary classifier for the leukocytes classification. This study shows the advantages of using this architecture and a deep learning technology to solve the objects classification task in medical digital images. The developed system allows one, in most cases, correctly and with a high speed to determine whether the white blood cell belongs to one of the two classes, which indicates to the possibility of using this system as an auxiliary tool for the blood hematological analysis.
Uniqueness, existence and solution of the direct boundary heat exchange problem for a weakly non-linear temperature conductivity coefficient
Authors: Tanana V P , Markov B A
Published: January 2021

This work is a preliminary result necessary for the formulation and solution of the inverse heat conduction problem for a weakly quasilinear equation. Nevertheless, the article has independent significance. For the direct heat conduction problem a solution is constructed in the form of a series with a small parameter, the existence of the solution, its uniqueness are proved, and a number of estimates are made - in particular, the rate of decrease of the solution at large times. The solution is built for a medium, part of which has a piecewise constant coefficient of thermal conductivity, and part of the medium has slightly non-linear thermal diffusivity. The construction of a classical solution is impossible due to the discontinuity of the thermal diffusivity, therefore, on the sections of the media the matching conditions are set - the conditions for the continuity of the solution and the condition for the continuity of the heat flux. The solution to the weakly quasilinear equation is constructed in the explicit form of a series with a small parameter, for which uniform convergence is proved. The decreasing of the solution at large times is proved as of time raised to the negative third power.
Modeling Under Uncertainty: a Comparison of Approaches
Authors: Dobronets B S , Popova O A
Published: January 2021

A new approach to data processing and uncertainty modeling based on the use of computational probabilistic analysis is considered. The basis of computational probabilistic analysis is numerical operations on probability density functions represented by piecewise polynomial functions. The problems of predicting the time series of distributions and estimating the probability densities of solutions of boundary value problems and systems of nonlinear equations with random coefficients are considered. Interval analysis, functional data analysis, symbolic data analysis and Monte Carlo method are currently used to study such data. A comparison of these approaches is given. Numerical examples show the effectiveness of the proposed approaches.
Hybrid Hybrid one step trigonometrically scheme with oscillatory solutions for solving initial value problems of second order
Authors: Adeniran A. O. , Longe I. O
Published: January 2021

A hybrid one step scheme with coefficients based on the step size and frequency of the trigonometric function used as basis function is derived. The constructed scheme is use to solve some problems with oscillating solutions. Stability properties of the developed scheme was also discussed. Numerical result obtained through the implementation of the scheme show its computation efficiency and accuracy over some of the existing ones (Abhulimen and Okunuga[1], Adeniran, Odejide and Ogundare [2], Alabi, Oladipo and Adesanya[3], Awoyemi, Adebile, Adesanya, and Anake, [5]) in the literature.
On damping parameters of Levenberg-Marquardt algorithm for nonlinear least square problems
Authors: Umar A O , Sulaiman I M , Mamat M , Waziri M Y , Zamri N
Published: January 2021

The Levenberg-Marquardt (LM) algorithm is a widely used method for solving problems related to nonlinear least squares. The method depends on a nonlinear parameter μ known as self-scaling parameter that affects the performance of the algorithm. In this paper we examine the effect of various choice of parameters and of relaxing the line search. Numerical results obtained are used to compare the performance using standard test problems which show that the proposed alternatives are promising.
Numerical treatment of first order delay differential equations using extended block backward differentiation formulae
Authors: Chibuisi C. , Osu B. O. , Edeki S. O. , Akinlabi G. O.
Published: January 2021

In this research, we developed and implemented extended backward differentiation methods (formulae) in block forms for step numbers k = 2, 3 and 4 to evaluate numerical solutions for certain first-order differential equations of delay type, generally referred to as delay differential equations (DDEs), without the use of interpolation methods for estimating the delay term. The matrix inversion approach was applied to formulate the continuous composition of these block methods through linear multistep collocation method. The discrete schemes were established through the continuous composition for each step number, which evaluated the error constants, order, consistency, convergent and area of absolute equilibrium of these discrete schemes. The study of the absolute error results revealed that, as opposed to the exact solutions, the lower step number implemented with super futures points work better than the higher step numbers implemented with super future points.
Baeckea frutescen L. essential oil was tested with Aedes aegypti larvae at various concentration levels
Authors: Jemi Renhart , Simanullang Sumiati , Sarinah  , Nuwa  , Luhan Gimson , Koroh Desy Natalia
Published: January 2021

Reducing the negative impact of using synthetic insecticides in a friendly manner. The alternative is to use a bioinsecticide. Ujung Atap (Baeckea frutescens L.) essential oil is one of them that has the potential as a bioinsecticide. Distillation of fresh leaves and dry leaves. Aedes aegypti larvicide mortality test on the resulting essential oil. A. aegypti mosquitoes that cause dengue fever. Analyze the essential oil content of B. frutescens L. by GC-MS. The Dried Leaf Distillation of B. Frutescens L. produces more and better essential oil than fresh leaves. Dried leaf essential oil is more deadly against larvicides than fresh leaf essential oil of B. frutescens L. Larvacide activity is classified as toxic. There are 25 compounds found in essential oils of fresh leaves and 23 compounds in dry leaves. The compound which is a gastric poison for insects is Limonene.
Fermentation of amylolytic yeast and lactic acid bacteria to improve the quality of modified cassava
Authors: Damayanti Ema , Ichsyani Meylida , Istiqomah Lusty , Anggraeni Ayu Septi , Kurniadi Muhamad
Published: January 2021

The amylolytic activity has been studied in yeast and lactic acid bacteria (LAB) which are isolated from various types of traditional fermented cassava. The study aimed to obtain yeast and LAB isolates which high amylolytic activity for inoculum in cassava fermentation. A total of 23 yeasts and 22 LAB isolates were isolated from Gatot, Tiwul, Tapai, and Cassava fermented using chloramphenicol yeast glucose (CYG) media for yeast and de Man Rogosa Sharpe agar (MRSA) + CaCO3 for LAB. Yeast amylolytic activity was tested using yeast extract peptone starch agar medium, while the amylolytic LAB used MRS + starch media with Lugol’s iodine indicator. Colonies showing clear zone areas were measured as amylase activity on the iodine complex method. Isolates that have the highest amylolytic activity were used as inoculum in cassava fermentation. Yeast Tr7 and LAB G6 isolates showed the highest amylolytic activity (0.0624 U/mL and 0.0627 U/mL). Cassava fermentation products using yeast Tr7 and BAL G6 resulted 52.06% of hydrogen cyanide (HCN) reduction higher than without inoculum (32.32%). According to biochemical identification using API 50 CHL kit, LAB G6 isolate was 99.6% identical with Pediococcys pentosaceus whereas biochemical identification using API 20 C AUX showed that yeast Tr7 was 95.8% identical with Candida tropicalis. The biochemical identification result was similar to the molecular identification result. In molecular identification using 28S rRNA sequence analysis revealed that yeast Tr7 was 99% similar with Candida tropicalis NITCSK13 strain. LAB G6 was 100% similar with Pediococcus pentosaceus BSS1375 strain using 16S rRNA sequence analysis. C. tropicalis Tr7 and P. pentosaceus G6 potentially used for inoculum in cassava fermentation process to improve cassava quality as a functional food.
Cold water swelling starch: methods to prepare and recent applications
Authors: Sarifudin Achmat , Sholichah Enny , Setiaboma Woro , Tongta Sunanta
Published: January 2021

Cold water swelling starch (CWSS) offers advantage of unique properties over its origin. Among methods available to prepare CWSS, heating starch in ethanol can be considered to be the simplest one. The unique features of CWSS are depending on its starch origin and degree of conversion; therefore, its application should be specific depending on the feature of CWSS. This review summarizes methods to produce CWSS, advantage of producing CWSS by heating starch in ethanol method, the most important features of CWSS that influence its applicability, and exploration on CWSS applications. We expect that this review will be beneficial for food industries that utilize modified starch as ingredient in their products as well as researchers who seek potential applications of CWSS.