bluuebunny/crossref_metadata_2025 huggingface dataset:
Mapping the water body area by using Sentinel 1 – SAR in dry season of 2023: A case study in Tri An reservoir
Authors: Tran Ha Phuong , Ha Tuan Cuong , Nguyen Thi Thuy Huong , Nguyen Ngoc Thy , Duong Ba Man , Danh Mon , Tran Phuc Dang , Pham Tuan Nhi
Published: March 2024

Monitoring water surface areas plays an extremely important role, especially for river and reservoir, lake systems that are significant for irrigation, hydropower and ecosystems etc. In the Tri An reservoir area, the main water source for Dong Nai province, and also where many people live in 4 districts of VinhCuu, DinhQuan, Thong Nhat and TrangBom. However, in the dry season of 2023, the weather became hot and dry with little rain due to the influence of the El Nino phenomenon. The water level of Tri An Lake has dropped to a record low in the past 12 years. Based on Sentinel 1 images and threshold method, this study conducted water surface extraction from January May 2023 of Tri An lake. The results showed that, from January to May 2023, the water surface area decreased from 26,270.97 hectares to 10,059.87 hectares. The most obvious decrease in water surface area was in Phu Ly and Ma Da communes (VinhCuu district) and the La Nga bridge section. This study has been a demonstration of the impact of global climate change on water resources, providing a basis for environmental resource management.
Assessing rainwater quality in Ca Mau Province: Unveiling the potential and viability for domestic usage
Authors: Tran Phuc Dang , Pham Thuc Bich Thi , Luu Tung Hai , Vu Lan Ngoc Thi , Do Dao Anh
Published: March 2024

The potential for exploiting rainwater in Ca Mau Province is immense due to its average annual rainfall of 1772 to 2500mm. Over a 15-year continuous monitoring period, the analysis of rainwater quality in Ca Mau Province reveals a prevailing alkaline tendency, with an average pH of 5.90, well within the established raw water quality standards. Concurrently, ongoing groundwater exploitation activities pose a significant threat to the natural aquifer reserves in the region. Recognizing this challenge, rainwater harvesting emerges as a pivotal strategy to alleviate the strain on groundwater extraction. The accumulation of freshwater during the rainy season in Ca Mau, facilitated by household rainwater storage tanks, offers a sustainable solution, ensuring a readily available supply for drinking and cooking needs during the dry season when rainfall is scarce. In addition, average tank capacity to meet the domestic water demand of a 5-member household is 10m3 for the whole year while this number increases to 18 20m3 during the dry years. These rainwater stored in tanks should be treated with chlorine or UV rays before use. Our study provides valuable evidence for policy makers and managers, based on the case study at Ca Mau, to develop a sustainable rainwater management plan for improving the livelihoods of millions people lacking freshwater in coastal zones of the Vietnamese Mekong Delta.
Particulate Matter Monitoring and Forecast with Integrated Low-cost Sensor Networks and Air-quality Monitoring Stations
Authors: Nguyen Huynh A. D. , Le Trung H. , Ha Quang P. , Duc Hiep , Azzi Merched
Published: March 2024

The fusion of low-cost sensor networks with air quality stations has become prominent, offering a cost-effective approach to gathering fine-scaled spatial data. However, effective integration of diverse data sources while maintaining reliable information remains challenging. This paper presents an extended clustering method based on the Girvan-Newman algorithm to identify spatially correlated clusters of sensors and nearby observatories. The proposed approach enables localized monitoring within each cluster by partitioning the network into communities, optimizing resource allocation and reducing redundancy. Through our simulations with real-world data collected from the state-run air quality monitoring stations and the low-cost sensor network in Sydney’s suburbs, we demonstrate the effectiveness of this approach in enhancing localized monitoring compared to other clustering methods, namely K-Means Clustering, Density-Based Spatial Clustering of Applications with Noise (DBSCAN) and Agglomerative Clustering. Experimental results illustrate the potential for this method to facilitate comprehensive and high-resolution air quality monitoring systems, advocating the advantages of integrating low-cost sensor networks with conventional monitoring infrastructure.
An Approach for Design of Air Quality Monitoring Systems
Authors: Shakhov Vladimir
Published: March 2024

Nowadays, society has realized the dangers of air pollution and is actively implementing air quality monitoring systems. These systems are based either on the deployment of a small number of fixed monitoring stations using high-level sensors, or on many lower-quality sensors integrated into the city infrastructure. However, there is a lack of tools that would allow developing recommendations and techniques for selecting the type of air sensors. In this work this gap is partially filled.
Effects of dust storm and wildfire events on phytoplankton growth in the Southern Ocean and Tasman Sea, southeast Australia
Authors: Nguyen Hiep Duc , Leys John , Riley Matthew , White Stephen , Azzi Merched , Trieu Toan , Salter David , Ji Fei , Nguyen Huynh , Chang Lisa Tzu-Chi , Monk Khalia , Firth Justine , Fuchs David , Barthelemy Xavier
Published: March 2024

Dust storms and wildfires occur frequently in southeastern Australia. Their effects on ecology, environment and population exposure have been the focus of many studies recently. Dust storms do not emit ground-sequestered carbon but wildfires emit significant quantities of carbon into the atmosphere. However, both natural events promote phytoplankton growth in water bodies because carbon, and other trace elements such as iron, deposit on the surface water of oceans and promote phytoplankton growth. Carbon di-oxide is reabsorbed by phytoplankton via photosynthesis. The carbon balance of dust storms and wildfires are not well known.This study focusses on the association of dust storms and wildfires in southeastern Australia with phytoplankton growth in the Southern Ocean and Tasman Sea due to the February 2019 dust storm event and the 2019-2020 black summer wildfires. The results show the similarities and differences in phytoplankton growth patterns and carbon reabsorption amount from these events.
Compatibility Assessment of Unactivated Internal Alkynes in ­Rhodium-Catalyzed [2+2+2] Cycloadditions
Authors: Watson Allan J. B. , Halford-McGuff John M. , McKay Aidan P.
Published: March 2024

Functionalized 1,2,4,5-tetrasubstituted benzenes are synthetically difficult or laborious to access. The Rh-catalyzed [2+2+2] cycloaddition of a diyne and internal alkyne offers a seemingly straightforward route to these scaffolds; however, this has been largely restricted to alkynes bearing activating (coordinating) functional groups, with very few examples of unactivated alkynes. In this work, we disclose an assessment of Rh-catalyzed [2+2+2] cycloadditions employing unactivated internal alkynes, focusing on the structural diversity and compatibility of both alkyne and diyne components. The limitations of this method are disclosed, with exceptionally bulky alkynes and specific functional groups undergoing side reactions. Furthermore, the practicalities of gram-scale reactions and catalyst recovery/reuse are demonstrated.
Extracellular vesicles in Alzheimer's disease
Authors: Berriel Pinho Victor Hugo , Daher João Paulo Lima , Kanaan Salim , Medeiros Thalia
Published: March 2024

Extracellular vesicles (EVs) are small vesicles released by cells that facilitate cell signaling. They are categorized based on their biogenesis and size. In the context of the central nervous system (CNS), EVs have been extensively studied for their role in both normal physiological functions and diseases like Alzheimer's disease (AD). AD is a neurodegenerative disorder characterized by cognitive decline and neuronal death. EVs have emerged as potential biomarkers for AD due to their involvement in disease progression. Specifically, EVs derived from neurons, astrocytes, and neuron precursor cells exhibit changes in quantity and composition in AD. Neuron-derived EVs have been found to contain key proteins associated with AD pathology, such as amyloid beta (Aß) and tau. Increased levels of Aß in neuron-derived EVs isolated from the plasma have been observed in individuals with AD and mild cognitive impairment, suggesting their potential as early biomarkers. However, the analysis of tau in neuron-derived EVs is still inconclusive. In addition to Aß and tau, neuron-derived EVs also carry other proteins linked to AD, including synaptic proteins. These findings indicate that EVs could serve as biomarkers for AD, particularly for early diagnosis and disease monitoring. However, further research is required to validate their use and explore potential therapeutic applications. To summarize, EVs are small vesicles involved in cell signaling within the CNS. They hold promise as biomarkers for AD, potentially enabling early diagnosis and monitoring of disease progression. Ongoing research aims to refine their use as biomarkers and uncover additional therapeutic applications.
Electrochemical Construction of C–S Bond: A Green Approach for Preparing Sulfur-Containing Scaffolds
Authors: Zou Ruonan , Yu Jingbo , Ying Ping
Published: March 2024

The organosulfur frameworks containing C–S bonds are important structural motifs in various biologically active molecules and functional materials. In this regard, transition-metal catalysis using chemical oxidants to prime reactions has emerged as the most common method, however, is prone to several side reactions such as dimerization and overoxidation. In recent years, organic electrosynthesis has become a hot topic due to its eco-friendly and mild process in which costly catalysts and toxic oxidants could be replaced by electrons. This perspective summarized the recently developed C–S bond electrosynthesis protocols, discussing and highlighting reaction features, substrate scope, as well as its application in pharmaceuticals, and the underlying reaction mechanisms. The study helps the development of electrochemical process-enabled C–S bond construction reactions in the future.
Cerebral palsy and sleep: nonpharmacological treatment and impact on the life of caregivers – an integrative review
Authors: Almeida Marcela Fischer de , Mello Suzane , Zonta Marise Bueno , Crippa Ana Chrystina
Published: March 2024

Background Children with cerebral palsy have a higher prevalence of sleep disorders, with numerous factors associated with a negative impact on the quality of life of caregivers.

Objective To identify factors related to sleep disorders, nonpharmacological treatment, and the impact on the lives of caregivers.

Methods The present literature review was carried out in the Latin American and Caribbean Center on Health Sciences Information (BIREME), the Cochrane Library, Scopus, PubMed, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycInfo, WorldCat, Web of Science, Latin American Literature on Health Sciences (LILACS), and Excerpta Medica Database (EMBASE), with the descriptors sleep, child, cerebral palsy, parents, and nursing. Studies available in Portuguese, English, or Spanish, published between 2010 and 2020, were our inclusion criteria. A total of 29 articles were included in the present review.

Results We considered nonpharmacological interventions effective support measures to drug-based treatments. The main sleep disorders in children with cerebral palsy are insomnia, parasomnias, nightmares, sleep bruxism, sleepwalking, sleep talking, disorders of initiation and maintenance of sleep, and sleep hyperhidrosis. Most studies point to a reduction in the quality of life of caregivers whose children have sleep disorders.

Conclusion Our review suggests the effectiveness of nonpharmacological treatments combined with the use of medications. Measures such as changes in sleep environment and routine are favorable strategies to improve sleep quality. In addition, children with sleep disorders negatively impact the quality of life of their caregivers.
On the Hinch–Kim dualism between singularity and Faxén operators in the hydromechanics of arbitrary bodies in Stokes flows
Authors: Procopio Giuseppe , Giona Massimiliano
Published: March 2024

We generalize the multipole expansion and the structure of the Faxén operator in Stokes flows obtained for bodies with no-slip to generic boundary conditions, addressing the assumptions under which this generalization is conceivable. We show that a disturbance field generated by a body immersed in an ambient flow can be expressed, independently on the boundary conditions, as a multipole expansion, the coefficients of which are the moments of the volume forces. We find that the dualism between the operator giving the disturbance field of an nth order ambient flow and the nth order Faxén operator, referred to as the Hinch–Kim dualism, holds only if the boundary conditions satisfy a property that we call Boundary-Condition reciprocity (BC-reciprocity). If this property is fulfilled, the Faxén operators can be expressed in terms of the (m, n)th order geometrical moments of the volume forces (defined in the article). In addition, it is shown that in these cases, the hydromechanics of the fluid-body system is completely determined by the entire set of the Faxén operators. Finally, classical boundary conditions of hydrodynamic applications are investigated in light of this property: boundary conditions for rigid bodies, Newtonian drops at the mechanical equilibrium, porous bodies modeled by the Brinkman equations are BC-reciprocal, while deforming linear elastic bodies, deforming Newtonian drops, non-Newtonian drops, and porous bodies modeled by the Darcy equations do not have this property. For Navier-slip boundary conditions on a rigid body, we find the analytical expression for low order Faxén operators. By using these operators, the closed form expressions for the flow past a sphere with arbitrary slip length immersed in shear and quadratic flows are obtained.
Non-Markovian processes on heteroclinic networks
Authors: Manicom Gray , Kirk Vivien , Postlethwaite Claire
Published: March 2024

Sets of saddle equilibria connected by trajectories are known as heteroclinic networks. Trajectories near a heteroclinic network typically spend a long period of time near one of the saddles before rapidly transitioning to the neighborhood of a different saddle. The sequence of saddles visited by a trajectory can be considered a stochastic sequence of states. In the presence of small-amplitude noise, this sequence may be either Markovian or non-Markovian, depending on the appearance of a phenomenon called lift-off at one or more saddles of the network. In this paper, we investigate how lift-off occurring at one saddle affects the dynamics near the next saddle visited, how we might determine the order of the associated Markov chain of states, and how we might calculate the transition probabilities of that Markov chain. We first review methods developed by Bakhtin to determine the map describing the dynamics near a linear saddle in the presence of noise and extend the results to include three different initial probability distributions. Using Bakhtin’s map, we determine conditions under which the effect of lift-off persists as the trajectory moves past a subsequent saddle. We then propose a method for finding a lower bound for the order of this Markov chain. Many of the theoretical results in this paper are only valid in the limit of small noise, and we numerically investigate how close simulated results get to the theoretical predictions over a range of noise amplitudes and parameter values.
Couette–Poiseuille flow of variable viscosity in a multilayered channel partially filled with a homogeneous anisotropic porous layer: Role of the glycocalyx in attenuating shear stress on endothelial cells
Authors: Pramanik Sanchita , Karmakar Timir
Published: March 2024

We present an analytical solution for the Couette–Poiseuille flow of variable viscosity in a multilayered channel partially filled with a homogeneous anisotropic porous layer. We establish a critical criterion that dictates the dominating factor when the flow is under the influence of shear and pressure gradient combined. This multilayered system resembles blood flow inside an artery where the fluid layer 1, fluid layer 2, and anisotropic porous layer describe the red blood cell layer, plasma layer, and glycocalyx layer, respectively. One of the novel features of this work is to understand the shear stress distribution on the liquid–porous interface (plasma membrane) and the bottom plate (endothelial cell layer) considering the variable viscosity of the fluid layer 1 while accounting for the anisotropic permeability of the porous medium. We use the obtained analytical solution to investigate the effect of the glycocalyx layer on the transmission of the fluid shear stress to the endothelial cell layer. We perceive that the shear stress distribution is more effective at the outer edge of the glycocalyx (plasma membrane) than the endothelial cell layer. On the other hand, the impact of the anisotropy on the shear stress distribution is more significant on the endothelial cell layer. This model is amenable to analytical solutions of the multilayered system considering the variable viscosity property of the blood and providing a framework for designing microfluidic systems that replicate biological glycocalyx, such as glycocalyx scaffolding.
An adaptive harmonic polynomial cell method for three-dimensional fully nonlinear wave-structure interaction with immersed boundaries
Authors: Tong Chao , Shao Yanlin , Bingham Harry B. , Hanssen Finn-Christian W.
Published: March 2024

To accurately simulate wave-structure interaction based on fully nonlinear potential flow theory, a three-dimensional (3 D) high-order immersed-boundary adaptive harmonic polynomial cell (IB-AHPC) method is proposed. Both the free surface and body surface are immersed in background octree cells that are adaptively refined near the boundaries of interest, thereby dramatically reducing computational costs without loss of accuracy. We also propose an easy-to-implement IB strategy to deal with possible instabilities in the time-domain solution arising from the intersection of Dirichlet–Neumann boundaries. For a linearized problem of wave-wall interaction, a matrix-based stability analysis is performed, providing mathematical support for the robustness of the proposed IB strategy. In contrast to the two-dimensional HPC method, compressed cells are found to offer superior stability compared to stretched cells in the vertical direction, while equal mesh aspect ratio in the horizontal plane is superior. Cubic octree cells are, however, still preferred in practice. The free surface is primarily described by a set of massless background wave markers; however, to address the challenges of IB methods in tracking the free surface evolution near the structure, additional body-fitted wave markers are introduced close to the waterline. The information exchange between these two sets of wave markers is realized by radial basis function (RBF) interpolation. While standard RBF schemes have grid-size-dependent filtering performance, we propose a normalized RBF scheme, which is then optimized in terms of the number of neighboring nodes, a smoothing coefficient and the basis functions. Excellent accuracy properties of the proposed 3 D IB-AHPC method are demonstrated by studying fully nonlinear wave propagation. The method is further applied to study relevant fully nonlinear wave-structure interaction problems, including sloshing in 3 D rectangular tanks and wave diffraction of a bottom-mounted cylinder in regular waves. Satisfactory agreement is demonstrated with existing experimental and numerical results, suggesting that the proposed 3 D IB-AHPC method is a promising potential-flow method in marine hydrodynamics.
Gondwanan flood basalts linked seismically to plume-induced lithosphere instability
Authors: Shi Yanan , Morgan Jason P.
Published: March 2024

Delamination of the continental lithospheric mantle is well recorded beneath several continents. However, the fate of the removed continental lithosphere has been rarely noted, unlike subducted slabs reasonably well imaged in the upper and mid mantle. Beneath former Gondwana, recent seismic tomographic models indicate the presence of at least 5 horizontal fast-wavespeed anomalies at ~600 km depths that do not appear to be related to slab subduction, including fast structures in locations consistent with delamination associated with the Paraná Flood Basalt event at ~134 Ma and the Deccan Traps event at ~66 Ma. These fast-wavespeed anomalies often lie above broad slow seismic wavespeed trunks at 500 to 700 km depths beneath former Gondwana, with slow wavespeed anomalies branching around them. Numerical experiments indicate that delaminated lithosphere tends to stagnate in the transition zone and mid-mantle above a mantle plume where it shapes subsequent plume upwelling. For hot plumes, the melt volume generated during plume-influenced delamination can easily reach ~2 to 4 × 10
6
km
3
, consistent with the basalt eruption volume at the Deccan Traps. This seismic and numerical evidence suggests that observed high-wavespeed mid-mantle anomalies beneath the locations of former flood basalts are delaminated fragments of former continental lithosphere, and that lithospheric delamination events in the presence of subcontinental plumes induced several of the continental flood basalts associated with the multiple breakup stages of Gondwanaland. Continued upwelling in these plumes can also have entrained subcontinental lithosphere in the mid-mantle to bring its distinctive geochemical signal to the modern mid-ocean spreading centers that surround southern and western Africa.
Electronic diffusion in a normal state of high-Tc cuprate YBa
2
Cu
3
O
6+x
Authors: Kokalj Jure
Published: March 2024

The bad metallic phase with resistivity above the Mott–Ioffe–Regel (MIR) limit, which appears also in cuprate superconductors, was recently understood by cold atom and computer simulations of the Hubbard model via charge susceptibility and charge diffusion constant. However, since reliable simulations can be typically done only at temperatures above the experimental temperatures, the question for cuprate superconductors is still open. This paper addresses this question by resorting to heat transport, which allows for the estimate of electronic diffusion and it further combines it with the resistivity to estimate the charge susceptibility. The doping and temperature dependencies of diffusion constant and charge susceptibilities are shown and discussed for two samples of YBa
2
Cu
3
O
6+x
. Results indicate strongly incoherent transport, mean free path corresponding to the MIR limit for the underdoped sample at temperatures above ~200 K and significant effect of the charge susceptibility on the resistivity.
An SOI-based post-fabrication process for compliant MEMS devices
Authors: Hao Yongcun , Wang Yanlong , Liu Yonghao , Yuan Weizheng , Chang Honglong
Published: March 2024

Fabricating compliant microelectromechanical system (MEMS) devices is challenging because they are easily damaged during fabrication. This paper presents a fabrication process based on the silicon-on-insulator (SOI) wafer for compliant MEMS devices. In the fabrication process, tethers were used to enhance the strength of the compliant devices during fabrication and finally melted with an electric current to release the device after fabrication. We discover that the power supply mode and voltage value are very critical for low-resistance tether melting. The fabrication results show that the yield rate of the compliant microgripper increased from 44% to 100%, which is a significant improvement compared with conventional processes. The successful fabrication of the microgripper proved that the proposed SOI-based post-fabrication process is feasible and can be used to fabricate different kinds of compliant devices.
Properties of collisional plasma sheath with ionization source term and two-temperature electrons in an oblique magnetic field
Authors: Chen Long , An Yuhao , Tan Congqi , Duan Ping , Cui Zuojun , Chen Junyu , Zhou Lina
Published: March 2024

A collisional magnetized plasma sheath with two groups of electrons has been studied using a fluid model including the effects of the ionization source term and the collisional force between ions and neutral atoms. Two kinds of non-Maxwellian descriptions of electron velocity distribution, non-extensive distribution and truncated distribution, are applied in the model, and the ionization effects of both kinds are considered. By applying Sagdeev potential, the modified Bohm sheath criterion is derived. The effects of ionization, magnetic field, and high-temperature electron concentration ratio on plasma sheath density, potential, sheath thickness, and ion kinetic energy are studied. In cases with high background gas density, ion density accumulates at the sheath edge position, forming a peak and manifesting as a rapid drop in the potential profile. The distribution characteristics of electrons have a significant impact on the transport properties of ions. Oscillations and non-monotonic characteristics of net charge near the sheath edge occur as the magnetic field angle increases, leading to an increase in the sheath layer width. It can be seen that in the case of a collisional sheath structure with high-temperature electrons, it is essential to consider the sheath changes induced by the ionization and the collisional force. Compared to a symmetric electron velocity distribution, the actual thickness of the sheath layer in a truncated electron distribution assumption could be significantly reduced.
Macroscopic phenomenon of exchange coupling and microscopic effect on magnetization reversal in sintered Nd–Fe–B magnets
Authors: Wang Chao , Li Bang-chen , Fu Yuan-zhe , Bai Suo , Liu Yan-li , Li Zhu-bai
Published: March 2024

Permanent magnets of Nd13.5Fe79.18M1.52B5.8 and Nd13.5Fe79.76M0.94B5.8 were prepared, respectively, via strip casting, jet milling and sintering followed by annealing. By adding the non-ferromagnetic elements M (Al, Cu, Ga and Zr) into the magnets, it could not only modify the microstructure, but also regulate the exchange coupling effect in the sintered magnets. From the macroscopic point of view, the recoil loops exhibit spring behavior in Nd13.5Fe79.76M0.94B5.8, indicating that the energy barrier can be overcome by the intergranular exchange coupling. From the microcosmic point of view, the exchange coupling can increase the domain wall size by suppressing the nucleation of reversed domains, and so the activation volume increases with thermal activation. In Nd13.5Fe79.76M0.94B5.8 the exchange coupling effect is stronger, and both the coercivity of 15.0 kOe and the remanence of 14.3 kGs are a little higher than those of Nd13.5Fe79.18M1.52B5.8 magnets in which the content of non-ferromagnetic elements is a little higher and the exchange coupling effect is weaker. Thus, the exchange coupling does not decrease the coercivity due to the exchange coupling suppressing the nucleation of reversed domains, though the microstructure is inhomogeneous in the sintered magnets of Nd13.5Fe79.76M0.94B5.8. Reducing the defect size and decreasing the defect concentration should be a practical way to improve the coercivity in Nd–Fe–B permanent magnets.
Analysis of mechanisms of bubble characteristics and molten pool dynamics in EDM based on a three-phase flow model
Authors: Peng Weiye , Tang Jiajing , Li Zhengkai , Qiu Zhiwei , Yin Mulong
Published: March 2024

Bubble characteristics and bubble volume fraction have significant effects on crater morphology and machining efficiency during electrical discharge machining (EDM) in liquid. Therefore, there is a need to elucidate the mechanism of bubble characteristics in EDM and analyze the mechanism of crater formation based on these bubble characteristics. However, since EDM is a transient multiphysics process, it is extremely difficult to understand bubble characteristics using experimental methods. Therefore, the generation, expansion, explosion, and disappearance of bubbles during EDM were simulated based on a three-phase flow model in this study. The model used the phase field method to track the boundary motion, judged the existence mode of each phase according to the order parameter gradient function, and analyzed the formation of crater morphology by the gradient of surface tension in the molten pool. The motion process of bubbles, the material removal mode, and the formation mechanism of crater morphology during the pulsed discharge were analyzed using the model. The results revealed that the periodic motion of the plasma channel would drive the molten pool to produce the corresponding periodic motion, and the bubbles would grow following the periodic motion of the molten pool. The material was removed in different ways in different periods, among which the removal mode of molten splash was predominant. The surface tension gradient inside the molten pool, the periodic motion of the molten pool, and the hydrostatic pressure in the molten region had a combined effect on bubble motion, the flow of the molten pool, and the formation of the crater morphology.
Chiral spin textures creation and dynamics in a rectangular nanostructure
Authors: Kandukuri Sateesh , Garcia-Sanchez Felipe , Thiruvikraman P K , Satya Narayana Murthy V
Published: March 2024

Controlled creation of stable chiral spin textures is required to use them as an energy-efficient information carrier in spintronics. Here we have studied the stable creation of isolated chiral spin texture (skyrmion and antiskyrmion) and its pair through the magnetization reversal of a rectangular nanostructure using spin-polarized currents. An isolated spin texture is created through a negative current pulse. Dynamics of the stable spin texture are explored under external magnetic fields, and the resonant frequencies are calculated. A stable skyrmion pair is created using an asymmetric current pulse, and their interaction is studied using the Thiele equation. The stability of isolated or paired spin texture depends on the Dzyaloshinskii–Moriya interaction strength, spin-polarized current density, and pulse duration. In addition, the stability of the skyrmion pair depends on their initial separation, and a threshold for the separation between skyrmions of 78 nm is observed.
Source–drain switching characteristics when coupled with a gate-controlled DBD in a microplasma switch
Authors: Chen Lichi , Wang Yaogong , Li Xueying , Ma Xiaoqin , Wang Wenjiang , Zhang Xiaoning
Published: March 2024

Microplasma switches have attracted considerable attention in harsh environment applications, such as satellites, space exploration, nuclear reactors, and oil drilling, because of their inherent characteristics. A microplasma switch is generally constructed from a source, drain, and gate electrodes, and current conduction is generated between the drain and source (DS), and modulated by the gate. In this work, to improve the gate lifespan and device stability, a microplasma switch with a gate dielectric barrier structure is fabricated due to the even and stable discharge of a dielectric barrier discharge (DBD), and a parameterized nanosecond pulse voltage signal is applied to the gate. Under the effect of the DS voltage, a pulsed DS current is triggered by the gate pulse since a large number of charged particles are generated by the gate DBD, which shows that the DS switching behavior is triggered by the gate pulse. The microplasma switch operates stably (with an average delay jitter of less than 50 ps) at the repetition frequencies (up to 80 kHz). Moreover, the influence of experimental conditions on the switching performance is systematically investigated. The conduction current and delay, which are related to the discharge intensity and speed, are influenced by the electric-field strength of the channel (determined from the pulse amplitude and DS voltage) and its variation rate (determined from the rising and falling edge time of the pulse). In addition, the device performance is influenced by varying the breakdown voltage of the DS (determined from the gas pressure multiplied by DS spacing), which can result in variation of the working coefficient. It is also influenced by varying the wall voltage (decided by pulse width and frequency), which can result in the decrease in the total voltage of the channel.
Excitation-wavelength-dependent photoluminescence in GaAs nanowires under high-pressure
Authors: Yin Xuetong , Liang Yilan , Li Lixia , Liu Shuang , Pan Dong , Wang Peng
Published: March 2024

GaAs nanowires (NWs) have wide application potential as near-infrared optical devices and the high-pressure strategy has been applied to modulate their crystal and electronic structures. As another typical thermodynamic parameter, temperature can also affect the optical performance of semiconductors. Here we report the excitation-wavelength-dependent photoluminescence (EWDP) in GaAs NWs under high-pressure conditions. The pressure for achieving the maximum photoluminescence (PL) intensity and bandgap transition from direct to indirect of GaAs NWs varies (1.7–2.7 GPa) with the wavelength of the incident lasers (633–473 nm). The Raman peak of GaAs NWs shifts towards higher frequency with increasing excitation wavelengths at the same high-pressure conditions, revealing the stronger heating effect induced by incident laser with the shorter wavelength. The relative temperature difference in GaAs NWs induced by two different lasers can be estimated up to 537 K, and the strong heating effect suppresses the light-emission efficiency in GaAs NWs. With increasing the pressure, the relative temperature difference presents a gradual declining trend and PL intensity presents an opposite trend, which relates to the pressure-induced suppression of nonradiative recombination in GaAs NWs. Our study provides insights into the mechanisms for the EWDP effect and an alternative route to modulate the high-pressure performance of nanodevices.
The effects of nontoxic bio-based substances (egg white) on the performance and passivation of ZnO nanorods arrays-based light emitting devices
Authors: Chuang Sung-Hao , Feria Denice Navat , Lo Yan-Shawn , Hsieh Tung-Han , Lin Tai-Yuan
Published: March 2024

An innovative approach is proposed to passivate the existing defects from metal oxide semiconductors by functionalizing nontoxic bio-based substances. As a demonstration, we synthesized zinc oxide nanorods (ZnO NRs) using a hydrothermal method and incorporated chicken egg white (albumen) as a passivator to the defects. X-ray diffraction analysis of ZnO NRs shows enhanced quality and crystallinity features after incorporating albumen. XPS measurements were performed not only to introduce the chemical bonding between the albumen and the bare ZnO NRs but also specifically provide evidence of successful capping and defect passivation to the surface layer of ZnO NRs. It was observed that when the albumen was annealed, it formed sulfhydryl groups and disulfide bonds (which created disulfide bridges) from the chemical reaction in irreversible thermal denaturation. Steady-state photoluminescence of ZnO NRs showed two emission bands, i.e. near band-edge emission (NBE) and deep-level emission (DL). The NBE is significantly improved as compared to DL emission after capping and annealing the albumen, while the quenching of DL emission confirmed the reduced defects arising from the surface of ZnO NRs. The advantages and enhanced characteristics of the albumen-capped ZnO NRs led to fabricating a stable and highly efficient light-emitting device. This work opens the great potential of utilizing nontoxic and low-cost biomaterials in passivating the defects of metal oxide nanomaterials for the development of bio-inspired and stable optoelectronic devices.
Design of MFAC greenhouse temperature controller based on LESO with disturbance estimation and fuzzy controller with parameter tuning
Authors: Wang Lina , Li Xue , Xu Mengjie , Wang Binrui
Published: March 2024

The proper temperature is essential for the growth and development of greenhouse crops. Therefore, it is necessary to determine an appropriate greenhouse temperature automatic control strategy. In this paper, a model-free adaptive greenhouse temperature control strategy is proposed by combining a linear extended state observer and a fuzzy controller. Specifically, the linear extended state observer is introduced to estimate model approximation error generated by pseudo gradient estimation. The fuzzy controller is used to correct the system parameter

ρ

online. The simulation results show that when there is no disturbance, compared with the typical model-free adaptive scheme, the MAE and RMSE of the greenhouse temperature control scheme proposed in this paper are reduced by 57.55% and 5.40% respectively. In the presence of custom disturbances, the proposed control scheme still has a faster response speed, stronger robustness, and higher control accuracy. And the proposed method can reduce the frequent action of the actuator, thus effectively reducing the energy cost.
Active low frequency band expansion mechanism of electromagnetic wave absorber composite structure
Authors: Zhang Rui , Cao Xiaobo , Chen Xu , Yuan Xujin , Gao Yanze , Sun Yingjian , Chen Mingji
Published: March 2024

Bandwidth expansion of modern antennas and communication systems raises growing demand for electromagnetic wave absorber in compatibility equipment. Single absorption mechanism is hard to reach well-balanced characteristics including wide bandwidth, low frequency absorption and small thickness. Based on the composite structure concept, composite structure for electromagnetic wave absorber’s active low frequency band expansion is proposed, by combining circuit-analog absorber and active absorber to form a superimposed structure. The characteristic of composite structure is better than the single absorber structure, which improves enhancement mechanism brought by the composite structure. Sample fabrication and experiments indicate reflectivity curve envelope reaches −10 dB in 2.15–18 GHz frequency range (relative bandwidth 157.3%), and the tunable absorption frequency range in low-frequency domain is greater than 1.3 GHz. The structure has good adaptation on TE and TM polarizations, as well as good angle insensitivity. This composite structure has application potential in intelligent response system related with electromagnetic compatibility, energy absorption and object security management.
Sex differences in left atrial volumes, mechanics, and stiffness in primary mitral regurgitation—a combined 2D and 3D echocardiographic study
Authors: Berg-Hansen Christian E , Sindre Rasmus Bach , Grymyr Lisa M D , Rogge Barbara , Valeur Andreas E , Urheim Stig , Hung Judy , Cramariuc Dana
Published: March 2024

Aims

Mitral regurgitation (MR) causes left atrial (LA) enlargement and impaired reservoir function. We assessed whether changes in LA size, strain, and stiffness in significant (moderate or greater) primary MR are sex-specific.

Methods and results

In the 3D Echocardiography and Cardiovascular Prognosis in Mitral Regurgitation study, 111 patients with primary MR were prospectively investigated with 2D and 3D echocardiography. MR was severe if the 3D regurgitant fraction was ≥50%. LA size was assessed by maximum, minimum, and pre-A 3D volume (LAV), mechanics by peak reservoir (LASr) and contractile strain, and stiffness by the ratio: mitral peak E-wave divided by the annular e′ velocity (E/e′)/LASr. Women were older, had higher heart rate, and lower body mass index and MR regurgitant volumes (P < 0.05). 3D LAV indexed for body surface area and LA contractile strain did not differ by sex, while LASr was lower (22.2 vs. 25.0%) and LA stiffness higher in women (0.56 vs. 0.44) (P < 0.05). In linear regression analysis, female sex was associated with higher LA stiffness independent of age, minimum LAV, left ventricular global longitudinal strain, diabetes, and coronary artery disease (R2 = 0.56, all P < 0.05). In logistic regression analysis, women had a four-fold (95% CI 1.2–13.1, P = 0.02) higher adjusted risk of increased LA stiffness than men.

Conclusion

Women with significant primary MR have more impaired LA reservoir mechanics and increased LA stiffness compared with men despite lower MR regurgitant volumes and similar indexed LA size. The findings reveal sex-specific features of LA remodeling in MR.

Trial Registration

ClinicalTrials.gov Identifier: NCT04442828
Life-threatening hemothorax due to rupture of pulmonary arteriovenous malformation during pregnancy
Authors: Kim Yeon Soo
Published: March 2024

Pulmonary arteriovenous malformation (PAVM) can worsen in pregnant women due to pregnancy-related physiological changes. If a PAVM ruptures, it can become life-threatening. A 24-year-old female patient at 22 weeks of gestation presented to the hospital with chest pain and dyspnea. A simple chest radiograph revealed that the right lung was almost completely collapsed due to massive pleural effusion, and the heart was displaced to the opposite side. Closed thoracostomy was performed and 2 l of blood was drained. Chest CT revealed the presence of a PAVM in the right upper lung. Emergency surgery was performed to resect the PAVM through thoracoscopic pulmonary wedge resection. The patient experienced disseminated intravascular coagulation and acute renal insufficiency after the surgery, but eventually recovered and was discharged without any complications on the sixth postoperative day.
Exploring Molecular Genetic Alterations and RAF Fusions in Melanoma: A Belvarafenib Expanded Access Program in Patients with RAS/RAF-Mutant Melanoma
Authors: Kim Kyoo Hyun , Cho Sungmin , Jeong Yeyeong , Baek Eun Sil , Lee Chung , Ryu Hyang-Joo , Noh Young Su , Hong Yoon-hee , Chung Kee Yang , Roh Mi Ryung , Oh Byung Ho , Kim Chang Gon , Jung Minkyu , Shin Sang Joon
Published: March 2024

Background

Melanoma incidence is on the rise in East Asia, yet studies of the molecular landscape are lacking in this population. We examined patients with melanoma who underwent next-generation sequencing (NGS) at a single tertiary center in South Korea, focusing on patients harboring NRAS or RAF alterations who received belvarafenib, a pan-RAF dimer inhibitor, through the Expanded Access Program (EAP).

Patients and Methods

Data were collected from 192 patients with melanoma who underwent NGS between November 2017 and May 2023. Variant call format data were obtained and annotated. Patients in the EAP received 450 mg twice daily doses of belvarafenib.

Results

Alterations in the RAS/RTK pathway were the most prevalent, with BRAF and NRAS alteration rates of 22.4% and 17.7%, respectively. NGS enabled additional detection of fusion mutations, including 6 BRAF and 1 RAF1 fusion. Sixteen patients with NRAS or RAF alterations received belvarafenib through the EAP, and disease control was observed in 50%, with 2 patients demonstrating remarkable responses.

Conclusions

Our study highlights the value of NGS in detecting BRAF, NRAS mutations and RAF fusions, expanding possibilities for targeted therapies in malignant melanoma. Belvarafenib showed clinical benefit in patients harboring these alterations. Ongoing trials will provide further insights into the safety and efficacy of belvarafenib.
Efficacy of traditional Chinese medicine containing hawthorn for hyperlipidemia: a systematic review and meta-analysis
Authors: Zhou Xiaoli , Chen Chun , Gao Zheng , Qian Zhiyong , Miao Jun
Published: March 2024

The traditional Chinese herb hawthorn is gaining attention for its potential to lower lipid levels due to its active components that positively influence lipid metabolism. Our meta-analysis of fourteen randomized controlled trials compared traditional Chinese medicine containing hawthorn with conventional lipid-lowering drugs for hyperlipidemia. Hawthorn-based medicine showed promise in reducing total cholesterol and triglycerides while increasing high-density lipoprotein cholesterol levels, albeit less effective than standard drugs in lowering low-density lipoprotein cholesterol. However, caution is needed due to methodological limitations in some trials, emphasizing the importance of further well-designed studies to clarify hawthorn’s efficacy in managing hyperlipidemia.
Rotational Malalignment After Intramedullary Nailing of Tibial Shaft Fractures Is Predictable
Authors: Cain Megan E. , Hendrickx Laurent A. M. , Sierevelt Inger , Kerkhoffs Gino M. M. J. , Jadav Bhavin , Doornberg Job N. , Jaarsma Ruurd L.
Published: March 2024

OBJECTIVES:

Intramedullary nailing is the treatment of choice for most tibial shaft fractures (TSF). However, an iatrogenic pitfall may be rotational malalignment. The aim of this retrospective analysis was to determine predictors of rotational malalignment following intramedullary nailing of TSF.

METHODS:

Design:

Retrospective study.

Setting:

Single level 1 trauma center.

Patient Selection Criteria:

Patients who had a unilateral intramedullary nailing for TSF with a low-dose bilateral postoperative CT to assess rotational malalignment.

Outcome Measures and Comparisons:

Bivariable analysis followed by multivariable analysis was then undertaken to assess for any independent predictors, such as fracture type/sight, surgeon experience, and side of fracture, predictive of rotational malalignment.

RESULTS:

In total, 154 patients (71% male, median age 37 years) were included in this study. Thirty-nine percent of variability in postoperative rotational malalignment could be explained using a model including (increased) tibial torsion of the noninjured side (mean [38.9 degrees ± 9.02 degrees] considered normal tibial torsion), side of tibial fracture, and spiral-type tibial fracture (R2 = 0.39, P ≤ 0.001, F = 31.40). In this model, there was a negative linear association between degrees of torsion on the noninjured side and rotational malalignment (−0.45, P < 0.001)—as baseline torsion increased from mean by 1 degree, malrotation in the opposite direction of 0.54 degrees seen. Positive linear associations between right-sided TSF and rotational malalignment (8.59 P < 0.001) as well as spiral fractures and rotational malalignment (5.03, P < 0.01) were seen.

CONCLUSIONS:

This study demonstrates that baseline reduced (internal) tibial torsion of the noninjured limb, spiral fractures, and right-sided TSF are predictive of postoperative external rotational malalignment. Conversely, increased baseline (external) tibial torsion of the noninjured limb and left-sided TSF are predictive of postoperative internal rotational malalignment. Surgeons may use this regression model preoperatively to predict what sort of postoperative rotational difference their patient may be prone to.

LEVEL OF EVIDENCE:

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.