bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical study on the structure, spectroscopic, and current–voltage behavior of 11-Cis and Trans retinal isomers in rhodopsin
Authors: Hamedian Amin , Vakili Mohammad , Brandán Silvia A. , Akbari Mahmood , Kanaani Ayoub , Darugar Vahidreza
Published: May 2024

In this study, the electronic transport properties of 11-Cis and Trans retinal, components of rhodopsin, were investigated as optical molecular switches using the nonequilibrium Green’s function (NEGF) formalism combined with first-principles density functional theory (DFT). These isomers, which can be reversibly converted into each other, were examined in detail. The structural and spectroscopic properties, including infrared (IR), Raman, nuclear magnetic resonance (NMR), and ultraviolet (UV) spectra, were analyzed using the hybrid B3LYP/6–311 +  + G** level of theory. Complete vibrational assignments were performed for both forms utilizing the scaled quantum mechanical force field (SQMFF) methodology. To evaluate the conductivity of these molecules, we utilized current–voltage (I-V) characteristics, transmission spectra, molecular projected self-consistent Hamiltonian (MPSH), HOMO–LUMO gap, and second-order interaction energies (E2). The trendline extrapolation of the current–voltage plots confirmed our findings. We investigated the effect of different electrodes (Ag, Au, Pt) and various connection sites (hollow, top, bridge) on conductivity. The Ag electrode with the hollow site exhibited the highest efficiency. Our results indicate that the Cis form has higher conductivity than the Trans form.
DASUNet: a deeply supervised change detection network integrating full-scale features
Authors: Miao Ru , Meng Geng , Zhou Ke , Li Yi , Chang Ranran , Zhang Guangyu
Published: May 2024

The change detection (CD) technology has greatly improved the ability to interpret land surface changes. Deep learning (DL) methods have been widely used in the field of CD due to its high detection accuracy and application range. DL-based CD methods usually cannot fuse the extracted feature information at full scale, leaving out effective information, and commonly use transfer learning methods, which rely on the original dataset and training weights. To address the above issues, we propose a deeply supervised (DS) change detection network (DASUNet) that fuses full-scale features, which adopts a Siamese architecture, fuses full-scale feature information, and realizes end-to-end training. In order to obtain higher feature information, the network uses atrous spatial pyramid pooling (ASPP) module in the coding stage. In addition, the DS module is used in the decoding stage to exploit feature information at each scale in the final prediction. The experimental comparison shows that the proposed network has the current state-of-the-art performance on the CDD and the WHU-CD, reaching 94.32% and 90.37% on F1, respectively.
Housekeeping protein-coding genes interrogated with tissue and individual variations
Authors: Tung Kuo-Feng , Pan Chao-Yu , Lin Wen-chang
Published: May 2024

Housekeeping protein-coding genes are stably expressed genes in cells and tissues that are thought to be engaged in fundamental cellular biological functions. They are often utilized as normalization references in molecular biology research and are especially important in integrated bioinformatic investigations. Prior studies have examined human housekeeping protein-coding genes by analyzing various gene expression datasets. The inclusion of different tissue types significantly impacted the discovery of housekeeping genes. In this report, we investigated particularly individual human subject expression differences in protein-coding genes across different tissue types. We used GTEx V8 gene expression datasets obtained from more than 16,000 human normal tissue samples. Furthermore, the Gini index is utilized to investigate the expression variations of protein-coding genes between tissue and individual donor subjects. Housekeeping protein-coding genes found using Gini index profiles may vary depending on the tissue subtypes investigated, particularly given the diverse sample size collections across the GTEx tissue subtypes. We subsequently selected major tissues and identified subsets of housekeeping genes with stable expression levels among human donors within those tissues. In this work, we provide alternative sets of housekeeping protein-coding genes that show more consistent expression patterns in human subjects across major solid organs. Weblink: https://hpsv.ibms.sinica.edu.tw.
Association between serum 25-hydroxyvitamin D3 level and cognitive impairment in older chronic kidney disease patients
Authors: Zhang Jialing , Zhang Aihua
Published: May 2024

This study aims to examine whether hypovitaminosis D was associated with cognitive impairment among chronic kidney patients with different level of albuminuria. This population-based cross-sectional study was conducted on elderly (over 60 years old) with urine albumin to creatinine ratio (UACR) ≥ 30 mg/g from 2011 to 2014 in the US National Health and Nutrition Examination Survey (NHANES). Cognitive function was assessed by the Consortium to Establish a Registry for Alzheimer’s Disease Word List Learning (CERAD). Subjects were divided into 2 groups according to the absence or presence of cognitive impairment and a propensity score matching (PSM) was further conducted. The association was assessed with Spearman correlation and logistic regression analysis. The positive association of 25-hydroxyvitamin D3 (25(OH)D3) and cognitive score was presented. PSM analysis revealed that a higher level of 25(OH)D3 correlated to a better cognitive function in CKD patients with albuminuria, especially in patients with 30 mg/g ≤ UACR < 300 mg/g. This study indicated that a low 25(OH)D3 level was associated with poor cognitive performance, especially in patients with microalbuminuria. Thus, early diagnosis of vitamin D insufficiency and an effective intervention might be a useful therapeutic strategy to prevent cognitive decline in patients with the progression of renal dysfunction.
The effect of a visual illusion and self-controlled practice on motor learning in children at risk for developmental coordination disorder
Authors: Shahbaz Reyhane , Saemi Esmaeel , Doustan Mohammadreza , Hogg Jennifer A. , Diekfuss Jed A.
Published: May 2024

Numerous efforts have been made to test the OPTIMAL theory of motor learning in healthy children and adult populations. However, only a small number of studies have tested this theory in children with cognitive-motor disorders, such as developmental coordination disorder (DCD). The present study aims to examine the individual and additive effects of a visual illusion and self-controlled practice on a golf putting task in children at risk for DCD based on the OPTIMAL theory. Forty children at risk for DCD (mean age = 8.57 ± 1.05 years) were randomly assigned to four experimental groups (1—small visual illusion + self-controlled practice; 2—big visual illusion + self-controlled practice; 3—small visual illusion + yoked; 4—big visual illusion + yoked). Following 12 pretest trials of a golf putting task, the participants completed 5 blocks of 12 trials of practice on the first day. A retention test (12 trials) and a transfer dual-task test (12 trials) were conducted on the second day. The results indicated that in retention test the big visual illusion + self-controlled practice group was significantly better than the small visual illusion + yoked group (p = 0.01), while there was not any other significant difference between groups at retention test as well as between all groups at practice phase and transfer test (p > 0.05 for all comparisons). In other words, an additive effect has been observed just in the retention test but not the practice phase as well as transfer test. In general, the results of this study support the OPTIMAL theory of motor learning in children at risk for DCD and suggests to all educators who work with these children to use the combination of the visual illusion with self-controlled practice to improve the motor learning of children at risk for DCD.
Simultaneous electromagnetic field probing system with Y‐shaped separation detection structure
Authors: Li Jianke , Xue Shan , Luo Chengyang , Cai Zongqi , Chen Yan , Chi Yuan
Published: May 2024

Simultaneous electromagnetic field probing system (SEMPS) has been popular in recent years. Herein, a simultaneous electromagnetic field probing system with Y‐shaped separation detection structure (SEMPS Y) is first proposed, in which the electric field probing region and the magnetic field probing region of the probe are separated by completely covering the shield along the loop and adding a pin‐shaped metal wire to capture the electric field, which are not the same as the classical dual probe structure. Combined with the non‐rotating asymmetric calibration method (NRACM), a 4‐port vector network analyser (VNA) and a highly symmetric grounded coplanar waveguide (GCPW) calibrator are used to solve the calibration matrix of the asymmetric SEMPS Y. The high symmetry GCPW calibrator is used to generate the standard electromagnetic field for calibration. The results of standing wave measurements show that the SEMPS Y can achieve ultrawideband electromagnetic field measurement of up to 20 GHz. Based on near‐field scanning measurements, SEMP Y can obtain results consistent with the calculation. In addition, when the probe is rotated 90° to invalidate the H‐field input, the decoupling curves of E‐field and H‐field are measured. Results show that the separation detection structure can effectively solve the cross‐coupling problem.
Radial velocities: Direct application of Pierre Connes’ shift-finding algorithm to cross-correlation functions
Authors: Bertaux Jean-Loup , Ivanova Anastasiia , Lallement Rosine
Published: May 2024

Context. Pipelines of state-of-the-art spectrographs dedicated to planet detection provide, for each exposure, series of cross-correlation functions (CCFs) built with a binary mask (BM), as well as the absolute radial velocity (RV) derived from the Gaussian fit of a weighted average CCFtot of the CCFs.

Aims. Our aim was to test the benefits of the application of the shift-finding algorithm developed by Pierre Connes directly to the total CCFtot, and to compare the resulting RV shifts (DRVs) with the results of the Gaussian fits. In a second step, we investigated how the individual DRV profiles along the velocity grid derived from the shift-finding algorithm can be used as an easy tool for detection of stellar line shape variations.

Methods. We developed the corresponding algorithm and tested it on 1151 archived spectra of the K2.5 V star HD 40307 obtained with ESO/ESPRESSO during a one-week campaign in 2018. Tests were performed based on the comparison of DRVs with RVs from Gaussian fits. DRV profiles along the velocity grid (DRV(i)) were scrutinized and compared with direct CCFtot ratios.

Results. The dispersion of residuals from a linear fit to RVs from 406 spectra recorded within a single night, a measure of mean error, was found to be σ = 1.03 and 0.83 m s−1 for the Gaussian fit and the new algorithm, respectively, which is a significant 20% improvement in accuracy. The two full one-week series obtained during the campaign were also fitted with a three-planet system Keplerian model. The residual divergence between data and best-fit model is significantly smaller for the new algorithm than for the Gaussian fit. Such a difference was found to be associated in a large part with an increase of ≃1.3 m s−1 in the difference between the two types of RV values between the third and fourth nights. Interestingly, the DRV(i) profiles reveal at the same time a significant variation of line shape.

Conclusions. The shift-finding algorithm is a fast and easy tool that provides additional diagnostics on the RV measurements in series of exposures. For observations made in the same instrumental configuration, and if line shapes are not varying significantly, it increases the accuracy of velocity variation determinations. On the other hand, departures from constancy of the DRV(i) profiles, as well as varying differences between RVs from this new method and RVs from a Gaussian fit can detect and report in a simple way line shape variations due to stellar activity.
Modeling LAEs in the epoch of reionization with OBELISK
Authors: Giovinazzo Emma , Trebitsch Maxime , Mauerhofer Valentin , Dayal Pratika , Oesch Pascal A.
Published: May 2024

Context. Lyman-α emitters (LAEs) are particularly useful objects in the study of the epoch of reionization. Lyman-α profiles can be used to estimate the number of ionizing photons that are able to escape galaxies, and therefore to understand which objects contributed to reionization. However, Lyman-α is a resonant line and its complex radiative transfer effects make the interpretation of the line challenging and require the use of appropriate radiative transfer methods for anything but the simplest gas distributions, such as uniform gaseous spheres, slabs, or cubes.

Aims. With this work, we aim to study the properties of simulated LAEs, and the robustness of these inferred properties during a change in the dust model. We also explore the Lyman continuum (LyC) escape fraction of these galaxies and compare our results with observationally calibrated methods to infer this quantity from the Lyman-α spectrum.

Methods. We used the radiative transfer code RASCAS to perform synthetic observations of 13 flux-selected galaxies from the OBELISK simulation at a redshift of z = 6, toward the end of the epoch of reionization. Each galaxy was observed in Lyman-α, as well as ionizing and nonionizing continuum from 48 different viewing angles.

Results. We show that the Lyman-α profiles emitted from a galaxy present large variations with a change in viewing angle and that the relation between peak separation and the Lyman-α escape fraction is not as strong as previously found, as we find lines of sight with both a low peak separation and a low escape fraction, due to their dust content. We also show that the properties of the Lyman-α line are reasonably robust during a change in the dust model. Lastly, we compare the LyC escape fractions that we derive from the simulation to three observationally calibrated methods of inferring this quantity. We determine that none of these relations reproduce the scatter that we find in our sample, and that high escape fraction lines of sight have both a low peak separation and a low dust extinction in the ultraviolet (UV).
Kinematic origin of white dwarfs in the solar neighborhood
Authors: Zubiaur Ainhoa , Raddi Roberto , Torres Santiago
Published: May 2024

Context. White dwarfs are considered to be efficient cosmochronometers. Thanks to the recent space-borne mission Gaia, a nearly complete sample up to about 100 parsecs from the Sun has been compiled. However, the Galaxy, as a dynamic system, implies that these objects may have very diverse origins. It is therefore of paramount importance to characterize the origins of white dwarfs from the different Galactic structure components found in our solar neighborhood.

Aims. We aim to compute the Galactic orbits for white dwarfs of the thin and thick disk, as well as the halo components observed in our solar neighborhood. On the basis of these determinations, we analyze the most probable regions of the Galaxy where they could have formed, along with the distribution of their orbital parameters and the observational biases introduced when constructing the local sample.

Methods. We used a detailed Galactic orbit integration package, in conjunction with a detailed population synthesis code specifically designed to replicate the different Galactic components of the white dwarf population. Synthetic stars were generated based on the current observational sample and their orbital integration allowed for the reconstruction of the population’s history.

Results. Our kinematic analysis of the white dwarf population reveals the ephemeral nature of the concept of the solar neighborhood, as the majority of thin-disk, thick-disk, and halo white dwarfs will have left our 100 pc neighborhood in approximately 3.30 Myr, 1.05 Myr, and 0.6 Myr, respectively. Moreover, the spatial distribution of the integrated thin-disk orbits suggests that 68% of these stars were formed at less than 1 kpc from the Sun, while most of the thick-disk members have undergone radial disk migration. Halo members are those stars that typically belong to the “inner halo”, given that their orbits mostly planar and do not extend beyond R = 20 − 25 kpc. Despite the observational bias, which mostly affects the oldest stars in the thick disk and halo, we show that the wider distribution of orbital parameters is well represented by the sample.

Conclusions. The solar neighborhood is a transitory concept, whereby its current population of white dwarfs originates from larger regions of the Galaxy. This fact must be taken into account when analyzing the overall properties of such a population, such as its age distribution, metallicities, and formation history. Even so, the kinematic properties observed by recent missions such as Gaia are representative of the total population up to a distance of approximately 500 pc.
Determining the dynamical age of the LMC globular cluster NGC 1835 using the ‘dynamical clock’
Authors: Giusti Camilla , Cadelano Mario , Ferraro Francesco R. , Lanzoni Barbara , Pallanca Cristina , Vesperini Enrico , Dalessandro Emanuele , Salaris Maurizio
Published: May 2024

In the context of the study of the size–age relationship observed in star clusters in the Large Magellanic Cloud (LMC) and the investigation of its origin, we present the determination of the structural parameters and the dynamical age of the massive cluster NGC 1835. We used the powerful combination of optical and near-ultraviolet images acquired with the WFC3 on board the HST to construct the star density profile from resolved star counts, determining the values of the core, half-mass, and tidal radii through comparison with the King model family. The same data also allowed us to evaluate the dynamical age of the cluster by using the ‘dynamical clock’. This is an empirical method that quantifies the level of the central segregation of blue stragglers stars (BSSs) within the cluster half-mass radius by means of the Arh+ parameter, which is defined as the area enclosed between the cumulative radial distribution of BSSs and that of a reference (lighter) population. The results confirm that NGC 1835 is a very compact cluster with a core radius of only 0.84 pc. The estimated value of Arh+ (0.30 ± 0.04) is the largest measured so far in the LMC clusters, providing evidence of a highly dynamically evolved stellar system. NGC 1835 fits nicely into the correlation between Arh+ and the central relaxation time and in the anti-correlation between Arh+ and the core radius defined by the Galactic and Magellanic Cloud clusters investigated to date.
Double line-of-sight cooperative location algorithm for non-cooperative targets in approaching process
Authors: WU Yinghao , YU Feng , LIU Jiaxin
Published: May 2024

Aiming at the problem of target location in the process of approaching non-cooperative targets, a target location algorithm based on double-line-of-sight cooperative angle-only measurement is proposed, and the accuracy of target location can be improved by optimizing the proximity configuration. Firstly, a two-spacecraft cooperative location scheme using only line-of-sight measurement is proposed, and a target location algorithm based on extended Kalman filter is designed. Then, by introducing normal distribution crossover operator, variable mutation distribution index and simulated catastrophe, the NSGA-Ⅱ algorithm is improved and applied to the optimization of proximity configuration. Finally, the numerical simulation results show that the proposed algorithm overcomes the problems of local convergence and slow convergence of the traditional algorithms, and the accuracy of target location is improved after configuration optimization.
Numerical calculation and analysis of aero-acoustic characteristics of tilt rotor in different tilt angles
Authors: YUAN Mingchuan , SUN Huixun , LI Zhibin , NIU Qingfeng , FAN Feng
Published: May 2024

The numerical calculation model for the aero-acoustic analysis of a tilt rotor was established by combining the free wake method and the FW-H (Ffowcs Williams-Hawkings) equation. The numerical method was validated by using the tilt rotor′s aero-acoustic test results. The aero-acoustic characteristics of dual tilt rotors that take into account the force and moment trim of an aircraft in its typical transition path were calculated. The unsteady air load of a rotor blade and its noise data in different observational positions were acquired. The acoustic directivity and sound pressure level of the tilt rotor in its different tilt angles were analysed. The results show that: the acoustic directivity characteristics of an isolate tilt rotor and dual tilt rotors were quite different due to the superposition and offset during noise radiation; the sound pressure level first increases and then decreases along with the rotor′s tilt angle; the maximum sound pressure level occurs at the tilt angle of 30 degree; the acoustic directivity and sound pressure level in different tilt angles vary due to multiple factors such as the Mach number at the rotor tip, air load and rotor orientation.
Film cooling characteristics of squealer tip of a turbine blade
Authors: WU Fangfang , XU Weijiang , LIU Cunliang , SHI Jingyin , YU Zeyu
Published: May 2024

The high-speed and high-temperature gap leakage flow in the turbine blade tip clearance directly scours the tip of the rotor blade and generates a local high-temperature region, so the active and passive control of the gap leakage flow is very important. Based on the pressure sensitive paint (PSP) experiment, the effects of density ratio, blowing ratio, and clearance height on the film cooling characteristics of the squealer blade tip were studied. The results show that with the increase of the density ratio, the film-cooling effectiveness of the squealer blade tip gradually increases, especially in the large clearance height, and the average cooling effect of the blade tip is increased by 35%. The effect of tip clearance height and blowing ratio on the tip surface cooling effect is not single. Under the condition of small tip clearance, the tip surface film-cooling effectiveness increases with the increase of the blowing ratio. Under the condition of large tip clearance, the tip surface film-cooling effectiveness decreases first and then increases with the increase of blowing ratio. At the same time, when the blowing ratio is small, the increase in tip clearance height improves the tip trailing edge area and the film-cooling effectiveness around the holes, and the average cooling effect of the blade tip surface increases by 6.85 %.
Exploring UAV autonomous navigation algorithm based on soft actor-critic
Authors: KOU Kai , YANG Gang , ZHANG Wenqi , LIU Xincheng , YAO Yuan , ZHOU Xingshe
Published: May 2024

The existing deep reinforced learning algorithms cannot see local environments and have insufficient perceptual information on UAV autonomous navigation tasks. The paper investigates the UAV's autonomous navigation tasks in its unknown environments based on the nondeterministic policy soft actor-critic (SAC) reinforced learning model. Specifically, the paper proposes a policy network based on a memory enhancement mechanism, which integrates the historical memory information processing with current observations to extract the temporal dependency of the statements so as to enhance the state estimation ability under locally observable conditions and avoid the learning algorithm from falling into a locally optimal solution. In addition, a non-sparse reward function is designed to reduce the challenge of the reinforced learning strategy to converge under sparse reward conditions. Finally, several complex scenarios are trained and validated in the Airsim+UE4 simulation platform. The experimental results show that the proposed method has a navigation success rate 10% higher than that of the benchmark algorithm and that the average flight distance is 21% shorter, which effectively enhances the stability and convergence of the UAV autonomous navigation algorithm.
Multi-fidelity aerodynamic data analysis by using composite neural network
Authors: ZHU Xingyu , MEI Liquan
Published: May 2024

Applying deep learning to aerodynamic data modeling has important practical significance. In this paper, the composite neural network is applied to the aerodynamics, making full use of the different characteristics of high and low-fidelity aerodynamic data. Multi-fidelity analysis technique is also used to analyze the correlation between the two types of data so as to establish the composite neural network. The experimental results show that the learning of multi-fidelity aerodynamic data based on the composite neural network model can better capture the mapping relationship between the aerodynamic input and the output data. And after comparing with the single neural network, it is verified that the present model has excellent performance in the regression modeling of aerodynamic data.
Subtitling the f-word into Arabic in Hollywood films: a corpus-based study
Authors: Sahari Yousef
Published: May 2024

This study investigates the prevailing strategies used by Arab translators when translating the f-word in subtitles. The study also determines whether these strategies are source-language-oriented or target-language-oriented. To address these research questions, a corpus of 90 Hollywood films released between 2000 and 2018 is analysed quantitatively and qualitatively, with a particular focus on their subtitles. Insights from descriptive translation studies (henceforth DTS), particularly Toury (2012), are also incorporated. The findings indicate that the functions of the f-word significantly influence the choice of subtitling strategies. Also, the use of Modern Standard Arabic in Arabic subtitles restricts the subtitlers’ linguistic options. Additionally, the nature of audiovisual translation plays a role in subtitler choices since the meaning of a word can be conveyed through gestures, images, or sounds on screen. In addition, the f-word is often translated into religious expressions, and omission is commonly used for certain functions as, for instance, an emphatic intensifier or idiomatic ‘set phrase’.
Solar-enhanced lithium extraction with self-sustaining water recycling from salt-lake brines
Authors: Xia Qiancheng , Deng Zehui , Sun Siwei , Zhao Wei , Ding Jie , Xi Beidou , Gao Guandao , Wang Chao
Published: May 2024

Lithium is an emerging strategic resource for modern energy transformation toward electrification and decarbonization. However, current mainstream direct lithium extraction technology via adsorption suffers from sluggish kinetics and intensive water usage, especially in arid/semiarid and cold salt-lake regions (natural land brines). Herein, an efficient proof-of-concept integrated solar microevaporator system is developed to realize synergetic solar-enhanced lithium recovery and water footprint management from hypersaline salt-lake brines. The 98% solar energy harvesting efficiency of the solar microevaporator system, elevating its local temperature, greatly promotes the endothermic Li
+
extraction process and solar steam generation. Benefiting from the photothermal effect, enhanced water flux, and enriched local Li
+
supply in nanoconfined space, a double-enhanced Li
+
recovery capacity was delivered (increase from 12.4 to 28.7 mg g
−1
) under one sun, and adsorption kinetics rate (saturated within 6 h) also reached twice of that at 280 K (salt-lake temperature). Additionally, the self-assembly rotation feature endows the microevaporator system with distinct self-cleaning desalination ability, achieving near 100% water recovery from hypersaline brines for further self-sufficient Li
+
elution. Outdoor comprehensive solar-powered experiment verified the feasibility of basically stable lithium recovery ability (>8 mg g
−1
) directly from natural hypersaline salt-lake brines with self-sustaining water recycling for Li
+
elution (440 m
3
water recovery per ton Li
2
CO
3
). This work offers an integrated solution for sustainable lithium recovery with near zero water/carbon consumption toward carbon neutrality.
A History of Tourism in Sri Lanka: A Story of Disasters and Opportunities
Authors: Fernando Shameena , Carr Neil
Published: May 2024

This case study reports on the evolution of tourism in Sri Lanka, a country that has endured multiple political shifts, economic changes, and a series of disasters. The frequent political shifts have shaped the policies and development of tourism. These political shifts and the 30-year civil war, tsunami, terrorist attacks (known as the Easter attacks), and COVID-19 are the major natural and man-made disasters that have interrupted the development of the economy. As a result, Sri Lanka has been put into a vulnerable position. An increased debt and foreign exchange crisis, and high inflation are present issues that the nation is dealing with. While these challenges have directly and indirectly impacted tourism in Sri Lanka the industry has shown significant resilience. Yet, the industry has more scope to improve its structure and tap into domestic tourism. Additionally, the ripple effect of disasters on tourism indicates the need to strengthen policies around disaster management and tourism.

Information

© The Authors 2024
Microstructure and properties of ZrB2-reinforced aluminum matrix composites consolidated by ECAP process
Authors: Jafari Hossein , Rajabi Masoud , Montazeri-Pour Mehdi
Published: May 2024

In this research work, the effects of mechanical alloying and subsequent compaction by ECAP on the microstructural, physical, and mechanical properties of Al-ZrB2 metal matrix composites (MMCs) were evaluated. To prepare composite powders, a mixture of Al and ZrB2 particles was mechanically alloyed at various times of 1, 6, 12, 18 and 24 h. SEM micrographs indicate that the size of the obtained particles decreases by increasing the time of mechanical alloying up to 18 h. However, after this time, increasing the time of mechanical alloying has led to an increase in the size of the particles. By means of mechanical alloying for 18 h, the average size of fine particles reached 823 nm, while coarse particles were 8 μm. The calculation via the use of XRD examination implies that the mean crystallite size of powder decreased from about 68 nm to 31 nm and 26.8 nm, for Al and Al-5%ZrB2 samples, respectively, while lattice strain increased from 0.25% to 0.64% and from 0.3% to 0.73% after 1 h to 24 h milling of same samples, respectively. However, the rate of crystallite size reduction after 12 h of mechanical alloying is gradually reduced, and that is reached its lowest level after 18 h. After that, increasing the time of mechanical alloying has led to a saturation in the lattice strain. In continue, the resulting composite powder was heated, consolidated and turned into bulk material by warm equal channel angular pressing (ECAP) at the temperature of 250 °C. The resultant optimum composite has been characterized by EDS elemental mapping. Microhardness measurements and shear punch tests were performed to evaluate the mechanical properties of the unreinforced and composite samples after the ECAP process. The Al-ZrB2 MMC bulk samples subjected to ECAP, with a ZrB2 amount of 5 wt%, had a relative density, hardness, and ultimate shear strength of 99.3%, 170 HV, and 151 MPa, respectively, using powders which have been mechanically alloyed up to 24 h.
Complete solutions of the Dirac equation with q-deformed hyperbolic Pöschl-Teller potential plus a trigonometric Scarf II potential
Authors: Kadja A
Published: May 2024

Under the condition of the spin symmetry, we rigorously solve the Dirac equation with the q − deformed hyperbolic Pöschl-Teller potential plus a trigonometric Scarf II potential. According to the values of the deformation parameter q, four different cases are considered. For the two cases q ≥ 1 and q ≤ − 1 with

1

2
α

ln

q

<
r
<
+
∞

, the analytical energy spectra and the spinor wave functions associated with the l

d
− wave bound states are obtained using a suitable approximation to the centrifugal potential term. When 0 < q < 1 or −1 < q < 0, the spinor wave functions for the s − wave bound states are derived and we find that the quantization conditions are transcendental equations which can be solved numerically. The special case q = 0 is also discussed.
Radiological assessment of commonly food crops in Southwestern Nigeria
Authors: Olaoye Morohunfoluwa Adeola , Abd El-Azeem S A , Olagbaju Peter Oluwadamilare , Lawal Rianat Yewande , Akanbi Ajitokewu Ridwan , Mostafa Mostafa Y A , Khalaf Hyam
Published: May 2024

Natural radionuclides are present in food items at different levels and are influenced by factors like background radiation, climate, and agricultural practices. These radionuclides play a crucial role in humans' internal radiation exposure. Notably, radionuclides within the decay series 238U and 232Th as well as 40K are significant concerns in radiation protection due to their prevalence and potential health risks. The activity concentrations of radionuclides 238U, 232Th, and 40K in several food crops consumed within Lagos city in Nigeria were measured using gamma spectrometry. The concentrations of 238U, 232Th, and 40K ranged from 0.90 to 55.30, BDL (Below Detection Limit) to 161.60 and 10.30 to 1075.20 Bqkg−1, respectively. The average radionuclide activity concentrations are below the acceptable global level, or the worldwide average values set by the United Nations Scientific Committee on the Effects of Atomic Radiation in 2000 (UNSCEAR, 2000), which are 35, 30, and 400 Bqkg−1 for 238U, 232Th, and 40K, respectively. The study calculated the annual effective dose for individuals consuming the studied food items, and the annual internal dose from ingesting was found to be 8.95 × 10–04
μSvy−1. It’s noteworthy that this computed value is below the worldwide value of 0.32 mSv y−1 set for the public. Additionally, the excess lifetime cancer risk (ELCR) value was 3.13 × 10−3
μSvy−1, which is within the world safe limit value (2.9 × 10−4
μSvy−1). Therefore, there is no potential radiological risk associated with the measured data.
First principles computation of novel hydrogen-doped CsSrO3 with excellent optoelectronic properties as a potential photocatalyst for water splitting
Authors: Zafar Sana , Zeba I , Zaman M , Shakil M , Gillani S S A
Published: May 2024

This research exhaustively inquired about the structural, photocatalytic, mechanical, and optoelectronic characteristics of the cubic perovskite CsSrO3−x Hx with the CASTEP code’s implementation of the GGA-PBE formalism. It aims to examine the characteristics of CsSrO3−xHx cubic perovskite with varied concentrations of substituents (x = 0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, 2.4, 2.7, and 3.0). The stability and synthesizability of the compound are guaranteed by the values of elastic constants and negative formation enthalpies. As H-insertion increases, there are variations in the values of anisotropy and elastic moduli. A semiconductor’s wide bandgap narrows as dopant concentration rises, changing its nature from indirect to direct. The findings imply that the compound’s electronic characteristics can be altered through the application of dopants, rendering them appropriate for a range of optoelectronic uses. The inclusion of hydrogen caused the structural change from cubic to tetragonal and orthorhombic. The distortion caused the lattice parameters to vary in values. Tolerance factor lies in range of 0.7–1 that ensures structural stability of CsSrO3−x Hx. Our computed results reveal the anisotropic nature of our compound. The obtained bandgap for CsSrO3−xHx indicates that both O2 evolution and H2 reduction are allowed since the requisite redox potentials are satisfied. Photocatalytic properties of CsSrO2.4H0.6 reveals that it is the best doped system as a potential candidate for water-splitting photocatalysis, as it has equal effectiveness to both oxidation and reduction processes. The bandgap was shown to decrease from 5.33 eV to 2.812 eV at complete hydrogen insertion, which also had an impact on the material’s optoelectronic characteristics. All the optical considerations such as dielectric functions, refractive indices, extinction coefficients, optical reflectivity, absorption coefficients, and loss functions are also thoroughly explained. The material exhibits mechanical stability along with ionic and covalent bonding.
A user-friendly visual brain-computer interface based on high-frequency steady-state visual evoked fields recorded by OPM-MEG
Authors: Ji Dengpei , Xiao Xiaolin , Wu Jieyu , He Xiang , Zhang Guiying , Guo Ruihan , Liu Miao , Xu Minpeng , Lin Qiang , Jung Tzyy-Ping , Ming Dong
Published: May 2024

Objective. Magnetoencephalography (MEG) shares a comparable time resolution with electroencephalography. However, MEG excels in spatial resolution, enabling it to capture even the subtlest and weakest brain signals for brain-computer interfaces (BCIs). Leveraging MEG’s capabilities, specifically with optically pumped magnetometers (OPM-MEG), proves to be a promising avenue for advancing MEG-BCIs, owing to its exceptional sensitivity and portability. This study harnesses the power of high-frequency steady-state visual evoked fields (SSVEFs) to build an MEG-BCI system that is flickering-imperceptible, user-friendly, and highly accurate. Approach. We have constructed a nine-command BCI that operates on high-frequency SSVEF (58–62 Hz with a 0.5 Hz interval) stimulation. We achieved this by placing the light source inside and outside the magnetic shielding room, ensuring compliance with non-magnetic and visual stimulus presentation requirements. Five participants took part in offline experiments, during which we collected six-channel multi-dimensional MEG signals along both the vertical (Z-axis) and tangential (Y-axis) components. Our approach leveraged the ensemble task-related component analysis algorithm for SSVEF identification and system performance evaluation. Main Results. The offline average accuracy of our proposed system reached an impressive 92.98% when considering multi-dimensional conjoint analysis using data from both the Z and Y axes. Our method achieved a theoretical average information transfer rate (ITR) of 58.36 bits min−1 with a data length of 0.7 s, and the highest individual ITR reached an impressive 63.75 bits min−1. Significance. This study marks the first exploration of high-frequency SSVEF-BCI based on OPM-MEG. These results underscore the potential and feasibility of MEG in detecting subtle brain signals, offering both theoretical insights and practical value in advancing the development and application of MEG in BCI systems.
Chronic kidney disease: a contraindication for using biodegradable magnesium or its alloys as potential orthopedic implants?
Authors: Zheng Lizhen , Zhang Ri , Chen Xin , Luo Ying , Du Wanting , Zhu Yuwei , Ruan Ye Chun , Xu Jiankun , Wang Jiali , Qin Ling
Published: May 2024

Magnesium (Mg) has gained widespread recognition as a potential revolutionary orthopedic biomaterial. However, whether the biodegradation of the Mg-based orthopedic implants would pose a risk to patients with chronic kidney disease (CKD) remains undetermined as the kidney is a key organ regulating mineral homeostasis. A rat CKD model was established by a 5/6 subtotal nephrectomy approach, followed by intramedullary implantation of three types of pins: stainless steel, high pure Mg with high corrosion resistance, and the Mg–Sr–Zn alloy with a fast degradation rate. The long-term biosafety of the biodegradable Mg or its alloys as orthopedic implants were systematically evaluated. During an experimental period of 12 weeks, the implantation did not result in a substantial rise of Mg ion concentration in serum or major organs such as hearts, livers, spleens, lungs, or kidneys. No pathological changes were observed in organs using various histological techniques. No significantly increased iNOS-positive cells or apoptotic cells in these organs were identified. The biodegradable Mg or its alloys as orthopedic implants did not pose an extra health risk to CKD rats at long-term follow-up, suggesting that these biodegradable orthopedic devices might be suitable for most target populations, including patients with CKD.
Multiaxial filament winding of biopolymer microfibers with a collagen resin binder for orthobiologic medical device biomanufacturing
Authors: Amin Heather , Tapp Austin , Kailes Benjamin , Sheean Andrew , Bulysheva Anna , Francis Michael P
Published: May 2024

Multiaxial filament winding is an additive manufacturing technique used extensively in large industrial and military manufacturing yet unexplored for biomedical uses. This study adapts filament winding to biomanufacture scalable, strong, three-dimensional microfiber (3DMF) medical device implants for potential orthopedic applications. Polylactide microfiber filaments were wound through a collagen ‘resin’ bath to create organized, stable orthobiologic implants, which are sized for common ligament (e.g. anterior cruciate ligament) and tendon (e.g. rotator cuff) injuries and can be manufactured at industrial scale using a small footprint, economical, high-output benchtop system. Ethylene oxide or electron beam sterilized 3DMF samples were analyzed by scanning electron microscopy (SEM), underwent ASTM1635-based degradation testing, tensile testing, ISO 10993-based cytocompatibility, and biocompatibility testing, quantified for human platelet-rich plasma (PRP) absorption kinetics, and examined for adhesion of bioceramics and lyophilized collagen after coating. 3DMF implants had consistent fiber size and high alignment by SEM. Negligible mass and strength loss were noted over 4 months in culture. 3DMF implants initially exceeded 1000 N hydrated tensile strength and retained over 70% strength through 4 months in culture, significantly stronger than conventionally produced implants made by fused fiber deposition 3D printing. 3DMF implants absorbed over 3x their weight in PRP within 5 min, were cytocompatible and biocompatible in vivo in rabbits, and could readily bind tricalcium phosphate and calcium carbonate coatings discretely on implant ends for further orthobiologic material functionalization. The additive manufacturing process further enabled engineering implants with suture-shuttling passages for facile arthroscopic surgical delivery. This accessible, facile, economical, and rapid microfiber manufacturing platform presents a new method to engineer high-strength, flexible, low-cost, bio-based implants for orthopedic and extended medical device applications.
Would the universal republic be viable?
Authors: Koenig-Archibugi Mathias
Published: May 2024

This chapter presents an empirical assessment of the viability of a democratic world state, i.e. its ability to retain democratic features over time if it were established. The first section explains how lasso—a machine-learning approach for prediction—is used to gain relevant information from the experience of democratic countries and to estimate the probability of survival of a democratic world state. The second section presents the measures of democracy and the variables that may be associated with democratic longevity and breakdown, including economic inequality and ethnic, linguistic, and religious diversity. The remainder of the chapter presents estimates from lasso Cox proportional hazards models and finds a world state would remain a democracy with high probability, in absolute terms and when compared to the survival probability of democracy in existing democratic states. The chapter also identifies some potential features of a world state that could further increase the resilience of its democratic institutions.
Evolutionary reversal of physical dormancy to nondormancy: evidence from comparative seed morphoanatomy of Argyreia species (Convolvulaceae)
Authors: Gunadasa D M Nethani H , Jayasuriya K M G Gehan , Baskin Jerry M , Baskin Carol C
Published: May 2024

Argyreia is the most recently evolved genus in the Convolvulaceae, and available information suggests that most species in this family produce seeds with physical dormancy (PY). Our aim was to understand the evolution of seed dormancy in this family via an investigation of dormancy, storage behaviour, morphology and anatomy of seeds of five Argyreia species from Sri Lanka. Imbibition, germination and dye tracking of fresh intact and manually scarified seeds were studied. Scanning electron micrographs and hand sections of the hilar area and the seed coat away from the hilar area were compared. Scarified and intact seeds of A. kleiniana, A. hirsuta and A. zeylanica imbibed water and germinated to a high percentage, but only scarified seeds of A. nervosa and A. osyrensis did so. Thus, seeds of the three former species are non-dormant (ND), while those of the latter two have physical dormancy (PY); this result was confirmed by dye-tracking experiments. Since >90% of A. kleiniana, A. hirsuta and A. zeylanica seeds survived desiccation to 10% moisture content (MC) and >90% of A. nervosa and A. osyrensis seeds with a dispersal MC of ~12% were viable, seeds of the five species were desiccation-tolerant. A. nervosa and A. osyrensis have a wide geographical distribution and PY, while A. kleiniana, A. hirsuta and A. zeylanica have a restricted distribution and ND. Although seeds of A. kleiniana are ND, their seed coat anatomy is similar to that of A. osyrensis with PY. These observations suggest that the ND of A. kleiniana, A. hirsuta and A. zeylanica seeds is the result of an evolutionary reversal from PY and that ND may be an adaptation of these species to the environmental conditions of their wet aseasonal habitats.
Temporal dynamics of faster neo-Z evolution in butterflies
Authors: Höök Lars , Vila Roger , Wiklund Christer , Backström Niclas
Published: May 2024

The faster-Z/X hypothesis predicts that sex-linked genes should diverge faster than autosomal genes. However, studies across different lineages have shown mixed support for this effect. So far, most analyses have focused on old and well-differentiated sex chromosomes, but less is known about the divergence of more recently acquired neo-sex chromosomes. In Lepidoptera (moths and butterflies), Z-autosome fusions are frequent, but the evolutionary dynamics of neo-Z chromosomes have not been explored in detail. Here, we analyzed the faster-Z effect in Leptidea sinapis, a butterfly with three Z chromosomes. We show that the neo-Z chromosomes have been acquired stepwise, resulting in strata of differentiation and masculinization. While all Z chromosomes showed evidence of the faster-Z effect, selection for genes on the youngest neo-Z chromosome (Z3) appears to have been hampered by a largely intact, homologous neo-W chromosome. However, the intermediately aged neo-Z chromosome (Z2), which lacks W gametologs, showed fewer evolutionary constraints, resulting in particularly fast evolution. Our results therefore support that neo-sex chromosomes can constitute temporary hot-spots of adaptation and divergence. The underlying dynamics are likely causally linked to shifts in selective constraints, evolution of gene expression, and degeneration of W-linked gametologs which gradually expose Z-linked genes to selection.