bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Response of a Warship’s Metal-Jet-Damaged Double-Layer Plates Subjected to the Subsequent Underwater Explosion
Authors: Huang Xiao , Mao Jia-Wei , Luo Xiao , Du Peng , Ouahsine Abdellatif
Published: May 2024

This paper examines the response characteristics of a warship’s double-layer plates under a secondary near-field explosion after the ship’s outer plate has been perforated by shaped metal jets. First, the effectiveness of the Coupled Eulerian–Lagrangian (CEL) method was validated, showing numerical simulations to be well aligned with experimental results. Subsequently, the damage inflicted on the outer plate by metal jets was simplified to a prefabricated orifice, further studying the explosive impact response of double-layer plates under different inter-compartmental water levels and charge distances. Our findings indicated the following: (1) shockwave and bubble pulsation loads are the main causes of deformation in the outer plate; (2) the driving of the outer plate and the flooding water between compartments are the main causes of deformation in the inner plate; and (3) deformation in the outer plate will decrease as the water level in the compartment increases, while deformation in the inner plate will increase with the increasing water level. Consequently, under certain specific damage, the ingress of water into a compartment effectively enhances the explosion resistance of the double-layer plates.
LWS-YOLOv7: A Lightweight Water-Surface Object-Detection Model
Authors: Li Zhengzhong , Ren Hongxiang , Yang Xiao , Wang Delong , Sun Jian
Published: May 2024

In inland waterways, there is a high density of various objects, with a predominance of small objects, which can easily affect navigation safety. To improve the navigation safety of inland ships, this paper proposes a new lightweight water-surface object-detection model named LWS-YOLOv7, which is based on the baseline model YOLOv7. Firstly, the localization loss function is improved and the w-CIoU function is introduced to reduce the model’s sensitivity to position deviations of small objects and to improve the allocation accuracy of positive and negative sample labels. Secondly, a new receptive field amplification module named GSPPCSPC is proposed to reduce the model’s parameters and enhance its receptive field. Thirdly, a small-object feature-fusion layer, P2, is added to improve the recall rate of small objects. Finally, based on the LAMP model pruning method, the weights with lower importance are pruned to simplify the parameters and computational complexity of the model, facilitating the deployment of the model on shipborne devices. The experimental results demonstrate that, compared to the original YOLOv7 model, the map of LWS-YOLOv7 increased by 3.1%, the parameters decreased by 38.8%, and the GFLOPS decreased by 28.8%. Moreover, the model not only has better performance and higher speed for input images of different sizes, but it can also be applied to different meteorological conditions.
Variation in the Occurrence of Salp and Doliolid Assemblages in the Northeastern East China Sea from 2019 to 2023
Authors: Choi Hyung-Uk , Jeong Young Seok , Choo Seohwi , Soh Ho Young
Published: May 2024

This study characterizes the distribution of salp and doliolid species in the northeastern East China Sea during spring and autumn and identifies the factors that regulate their abundance. The data were collected over four years (2019–2023, except 2020). During the survey period, the Tsushima Warm Current Surface and Bottom (TWCS and TWCB, respectively) and Yellow Sea Cold Bottom Water were influential in spring, while the Changjiang Diluted Water, Coastal Water, TWCS, and TWCB were dominant in autumn. The mean sea surface temperature (SST) and sea surface salinity (SSS) in spring and the mean SST in autumn statistically decreased (p < 0.05), while the mean SSS in autumn statistically increased (p < 0.05). The spatial distribution of salp and doliolid species remained consistent in spring and autumn, although the dominant assemblage shifted seasonally. Spring was predominantly characterized by an abundance of salp species, whereas doliolid species were dominant in autumn, with their distribution and abundance influenced by different environmental factors such as temperature and salinity in spring and food availability in autumn. Our results provide valuable data on the factors affecting the presence of salp and doliolid species in the northeastern East China Sea.
Identification and Pathogenicity of Pestalotioid Species on Alpinia oxyphylla in Hainan Province, China
Authors: Cui Xiufen , Hao Zhigang , Chen Menghuai , Song Shuang , Zhang Jinan , Li Yingbin , Li Jianqiang , Liu Yixiang , Luo Laixin
Published: May 2024

Alpinia oxyphylla is a traditional Chinese medicinal plant with a medicinal history of more than 1700 years. Ring leaf blight (RLB) disease, caused by pestalotioid species, is an important disease of A. oxyphylla, seriously affecting the yield and quality of its fruits. The causal agent of RLB disease has not been systematically identified or characterized yet. In this study, thirty-six pestalotioid strains were isolated from the leaves and stems of A. oxyphylla that was collected from six cities of Hainan province, China. Based on the multi-locus phylogeny (ITS, tef-1α and tub2) and morphological characteristic analyses, seventeen species belonging to three genera (Neopestalotiopsis, Pestalotiopsis and Pseudopestalotiopsis) were identified, and six new species (N. baotingensis, N. oblatespora, N. olivaceous, N. oxyphylla, N. wuzhishanensis and N. yongxunensis) were described. Pathogenicity tests revealed that strains of Neopestalotiopsis species caused more severe ring leaf blight on A. oxyphylla than strains of Pestalotiopsis and Pseudopestalotiopsis under wounded inoculation conditions.
Study on Tianjin Land-Cover Dynamic Changes, Driving Factor Analysis, and Forecasting
Authors: Zhang Zhaoxu , Wei Yuzhao , Li Xutong , Wan Dan , Shi Zhenwei
Published: May 2024

Land-use and land-cover changes constitute pivotal components in global environmental change research. Through an examination of spatiotemporal variations in land cover, we can deepen our understanding of land-cover change dynamics, shape appropriate policy frameworks, and implement targeted environmental conservation strategies. The judicious management of land is a critical determinant in fostering the sustainable growth of urban economies and enhancing quality of life for residents. This study harnessed remote sensing data to analyze land-cover patterns in Tianjin over five distinct time points: 2000, 2005, 2010, 2015, and 2020. It focused on evaluating the evolving dynamics, transition velocities, and transformation processes across various land categories within the region. Utilizing dynamic analysis and a transition matrix, the study traced shifts among different land-use classes. The center-of-gravity migration model was employed to elucidate land-cover pattern evolution. This research also integrated pertinent land-cover statistics to offer a holistic perspective on Tianjin’s land-cover transformations. Employing the CA–Markov model, we projected the prospective spatial layout of land cover for the area. Our findings revealed the following. (1) From 2000 to 2020, Tianjin experienced a significant reduction in cropland, forest, grassland, and water areas, alongside a substantial increase in impervious. (2) The impervious surface’s center of gravity, initially in Beichen District, shifted 4.20 km northwestward at an average rate of 0.84 km per year. (3) Principal component analysis indicated that the growth in the output value of the secondary and forestry industries is a key driver in expanding Tianjin’s impervious-surface area. (4) Predictions for 2025 suggest an increase in Tianjin’s impervious-surface area to 4659.78 km2, with a concurrent reduction in cropland to 5656.18 km2. The insights gleaned from this study provide a solid theoretical foundation and empirical evidence, aiding in the formulation of informed land-use strategies, the preservation of urban land resources, and guiding principles for sustainable urban development.
Incentivizing Civic Engagement at Public and Private Universities: Tax Exemptions, Laws, and Critical Dialogues
Authors: Morrow Eric , Thompson Casey , Jones Payton , Kabala Boleslaw Z.
Published: May 2024

What are the differences in how public and private institutions of higher education, with religious schools as a subset of private colleges and universities, approach on-campus protests in a framework of civic engagement? Unfortunately, public, private, and religious schools have all restricted opportunities of speech, assembly, and protest, despite in many cases state and federal courts ruling that this is against the law. With the goal of increasing the civic capacities of students at all institutions of higher education, we propose a mechanism of partial revocation of tax exemptions at universities that do not currently uphold a robust understanding of civic engagement opportunities for all students, which will apply to any college or university receiving federal funding, consistent with the constitutional tradition of free speech still exemplified by Brandenburg v. Ohio and the “national policy” test of Bob Jones University vs. United States. In doing so, we build on the critique of exemptions in the recent work of Vincent Phillip Munoz on religious liberty. By opting only for incentives and by not even incentivizing private institutions that continue to restrict civic engagement but that do not accept federal dollars, we affirm and support a mutually beneficial ongoing dialogue among public, private, and religious schools. This dialogue, as it is sharpened and maintained in place by our recommended policies, is also consistent with pluralism as conceptualized by Jacob Levy.
Partial Hepatectomy and Ablation for Survival of Early-Stage Hepatocellular Carcinoma Patients: A Bayesian Emulation Analysis
Authors: Wang Jiping , Im Yunju , Wang Rong , Ma Shuangge
Published: May 2024

Partial hepatectomy and ablation therapy are two widely used surgical procedures for localized early-stage hepatocellular carcinoma (HCC) patients. This article aimed to evaluate their relative effectiveness in terms of overall survival. An emulation analysis approach was first developed based on the Bayesian technique. We estimated propensity scores via Bayesian logistic regression and adopted a weighted Bayesian Weibull accelerated failure time (AFT) model incorporating prior information contained in the published literature. With the Surveillance, Epidemiology, and End Results (SEER)-Medicare data, an emulated target trial with rigorously defined inclusion/exclusion criteria and treatment regimens for early-stage HCC patients over 66 years old was developed. For the main cohort with tumor size less than or equal to 5 cm, a total of 1146 patients were enrolled in the emulated trial, with 301 and 845 in the partial hepatectomy and ablation arms, respectively. The analysis suggested ablation to be significantly associated with inferior overall survival (hazard ratio [HR] = 1.35; 95% credible interval [CrI]: 1.14, 1.60). For the subgroup with tumor size less than or equal to 3 cm, there was no significant difference in overall survival between the two arms (HR = 1.15; 95% CrI: 0.88, 1.52). Overall, the comparative treatment effect of ablation and partial hepatectomy on survival remains inconclusive. This finding may provide further insight into HCC clinical treatment.
SARS-CoV-2 Positivity in Foreign-Born Adults: A Retrospective Study in Verona, Northeast Italy
Authors: Lotti Virginia , Spiteri Gianluca , Caliskan Gulser , Monaco Maria Grazia Lourdes , Gibellini Davide , Verlato Giuseppe , Porru Stefano
Published: May 2024

We compared SARS-CoV-2 positivity between the foreign-born adult working population and Italians living in the Verona area to investigate whether being a foreign-born adult could confer an increased risk of infection or lead to a diagnostic delay. The present study included 105,774 subjects, aged 18–65 years, tested for SARS-CoV-2 by nasopharyngeal swabs and analyzed at the University Hospital of Verona between January 2020 and September 2022. A logistic regression model was used, controlling for gender, age, time of sampling, and source of referral. A higher proportion of SARS-CoV-2 positivity in Italian (30.09%) than in foreign-born (25.61%) adults was reported, with a higher proportion of SARS-CoV-2 positivity in men than women in both cohorts analyzed. The difference in swab positivity among Italian and foreign-born adults was the highest in people aged 18–29 years (31.5% vs. 23.3%) and tended to disappear thereafter. Swab positivity became comparable between Italian and foreign-born adults during the vaccination campaign. Multivariable analysis confirmed the lower risk of swab positivity among foreign-born adults (OR = 0.85, 95% CI 0.82–0.89). In the Verona area, foreign-born adults showed a lower rate of SARS-CoV-2 positivity than the native population, likely because of underdiagnosis. Hence, public health should increase attention toward these particularly vulnerable populations.
Research on Lateral Resistance Performance of Prestressed Cross-Laminated Timber–Concrete Composite Structures under Reciprocating Loads
Authors: Xu Yong , Huang Xin , Zhang Yingda , Qu Yusen , Fan Yujie , Yang Guoqin
Published: May 2024

Cross-Laminated Timber (CLT) and concrete composite structures represent an architectural system that integrates the strengths of both materials. In this innovative configuration, the CLT and concrete collaborate synergistically, harnessing their individual merits to achieve enhanced structural performance and functionality. Specifically, the CLT offers a lightweight design, superior bending resistance, and immense engineering plasticity, while concrete boasts exceptional compressive strength and durability. This study investigates the mechanical performance of CLT–concrete composite structures through quasi-static reciprocating loading tests in three full-scale CLT shear wall samples. Designed with varying initial prestressing forces and dimensions of the CLT panel, the prestressed CLT–concrete structures demonstrated a reduced dependence on the steel nodes, resulting in an increase in yield load, yield displacement, and maximum load-carrying capacity. Maximum capacity increased by 39.8% and 33.7% under initial prestressing forces of 23 kN and 46 kN on steel strands. Failure occurred due to localized compressive failure on prestressed steel strands and anchor plates. ABAQUS finite element analysis established three refined models, revealing that the increased initial prestressing force moderately enhanced stiffness but reduced ductility under similar cross-sectional dimensions. Furthermore, under consistent CLT material, dimensions, prestressing force, and loading conditions, prestressed CLT–concrete structures exhibited a higher maximum load-bearing capacity than prestressed CLT–steel composite structures. This study proposes structural design recommendations based on experimental and simulation results, incorporating specific assumptions.
Facile Synthesis and Properties of Highly Porous Quartz Fiber-Reinforced Phenolic Resin Composites with High Strength
Authors: Tao Xin , Wan Yange , Zhang Ruoyu , Zhang Yuqing , Wang Yu , Yu Xiaolei , Wang Mingchao
Published: May 2024

Lightweight and high-strength insulation materials have important application prospects in the aerospace, metallurgical, and nuclear industries. In this study, a highly porous silica fiber reinforced phenolic resin matrix composite was prepared by vacuum impregnation and atmospheric drying using quartz fiber needled felt as reinforcement and anhydrous ethanol as a pore-making agent. The effects of curing agent content on the structure, composition, density, and thermal conductivity of the composite were studied. The mechanical properties of the composite in the xy direction and z direction were analyzed. The results showed that this process can also produce porous phenolic resin (PR) with a density as low as 0.291 g/cm3, where spherical phenolic resin particles are interconnected to form a porous network structure with a particle size of about 5.43 μm. The fiber-reinforced porous PR had low density (0.372~0.397 g/cm3) and low thermal conductivity (0.085~0.095 W/m·K). The spherical phenolic resin particles inside the composite were well combined with the fiber at the interface and uniformly distributed in the fiber lap network. The composite possessed enhanced mechanical properties with compressive strength of 3.5–5.1 MPa in the xy direction and appeared as gradual compaction rather than destruction as the strain reached 30% in the z direction. This research provides a lightweight and high-strength insulation material with a simple preparation process and excellent performance.
Mullite-like SmMn2O5-Derived Composite Oxide-Supported Ni-Based Catalysts for Hydrogen Production by Auto-Thermal Reforming of Acetic Acid
Authors: Chen Hui , Chen Qi , Hu Xiaomin , Ding Chenyu , Huang Lihong , Wang Ning
Published: May 2024

The x%Ni/Sm2O3-MnO (x = 0, 10, 15, 20) catalysts derived from SmMn2O5 mullite were prepared by solution combustion and impregnation method; auto-thermal reforming (ATR) of acetic acid (HAc) for hydrogen production was used to explore the metal-support effect induced by Ni loadings on the catalytic reforming activity and product distribution. The 15%Ni/Sm2O3-MnO catalyst exhibited optimal catalytic performance, which can be due to the appropriate Ni loading inducing a strong metal–support interaction to form a stable Ni/Sm2O3-MnO active center, while side reactions, such as methanation and ketonization, were well suppressed. According to characterizations, Sm2O3-MnO mixed oxides derived from SmMn2O5 mullite were formed with oxygen vacancies; nevertheless, loading of Ni metal further promoted the formation of oxygen vacancies, thus enhancing adsorption and activation of oxygen-containing intermediate species and resulting in higher reactivity with HAc conversion near 100% and hydrogen yield at 2.62 mol-H2/mol-HAc.
Recent Advances in Self-Powered Tactile Sensing for Wearable Electronics
Authors: Liu Ling-Feng , Li Tong , Lai Qin-Teng , Tang Guowu , Sun Qi-Jun
Published: May 2024

With the arrival of the Internet of Things era, the demand for tactile sensors continues to grow. However, traditional sensors mostly require an external power supply to meet real-time monitoring, which brings many drawbacks such as short service life, environmental pollution, and difficulty in replacement, which greatly limits their practical applications. Therefore, the development of a passive self-power supply of tactile sensors has become a research hotspot in academia and the industry. In this review, the development of self-powered tactile sensors in the past several years is introduced and discussed. First, the sensing principle of self-powered tactile sensors is introduced. After that, the main performance parameters of the tactile sensors are briefly discussed. Finally, the potential application prospects of the tactile sensors are discussed in detail.
Enhancement of the Corrosion Properties of Al–10%Si–2%Cu Alloys with La Addition
Authors: Kim Kyeonghun , Heo Uro , Yang Haewoong , Kang Namhyun
Published: May 2024

Al–10%Si–2%Cu alloys have been widely used in high-value industries (e.g., aerospace and automobiles) because of their lower specific gravity; however, galvanic corrosion rendered these alloys to have poor corrosion resistance. Therefore, the microstructure and corrosion properties of Al–10%Si–2%Cu alloys were investigated with respect to the lanthanum (La) content. All Al alloy samples were synthesized using gravity casting, with added La contents of 0.00, 0.25, 0.50, 0.75, and 1.00 wt%, and were characterized using microstructural characteristics analysis and electrochemical tests. Adding 0.5 wt% La (xLa-0.5) indicated the finest structure, which had a 4% lower α-Al area fraction than the La-free alloy (xLa-0). However, the area fraction of a 1 wt% La-added (xLa-1) alloy was 2.4% higher than that of xLa-0. The corrosion current density (Icorr) of the xLa-0.5 was 1.09 μA/cm2, representing a 68% decrease as compared to that of xLa-0, and xLa-0.5 reached the highest polarization resistance value (7.32 × 103 Ω·cm2). The improvement in corrosion resistance of xLa-0.5 was due to the rapid and dense formation of a passivation layer induced by its fine structure, as well as the precipitated phase by enhancing the dispersibility of Cu.
Durability of Prestressed Piles in a Leachate Environment
Authors: Wang Yu , Deng Min , Zhang Rihong , Yu Xuming , Xue Junzhong , Zhang Jing
Published: May 2024

Prestressed pipe piles are common concrete components characterized by dense concrete structures and favorable mechanical properties, and thus, extensively used as coastal soft soil foundations. However, their durability in harsh environments has not been fully clarified. In this study, leachate from an actual landfill site was collected from the east coast of China as the corrosive medium, and the corrosion process was accelerated by electrifying prestressed pipe piles. The results demonstrated that the concentration of chloride ions in the concrete of the prestressed pile increased with the increase in corrosion time. Moreover, the experimental corrosion of these prestressed piles in the drying–wetting cycle proved to be the most severe. However, a protective layer of epoxy resin coating can effectively inhibit the diffusion of chloride ions into the interior of the piles. The final theoretical corrosion amounts of the piles were 1.55 kg, 1.20 kg, and 1.64 kg under immersion, epoxy resin protection, and a drying–wetting cycle environment. The application of epoxy resin reduced chloride penetration by 22.6%, and the drying–wetting cycle increased chloride penetration by 5.8%, respectively, with corresponding corrosion potentials following similar patterns. The actual corrosion depth of the welding seam was 3.20 mm, and there was a large corrosion allowance compared with the requirement (6.53 mm) for the ultimate bending moment. In summary, these prestressed piles exhibited good durability in a leachate environment.
Mild Hybrid Powertrain for Mitigating Loss of Volumetric Efficiency and Improving Fuel Economy of Gasoline Vehicles Converted to Hydrogen Fueling
Authors: Bibiloni Sebastian , Irimescu Adrian , Martinez-Boggio Santiago , Merola Simona , Curto-Risso Pedro
Published: May 2024

The pursuit of sustainable and environmentally friendly transportation has led to the exploration of alternative fuel sources, among which hydrogen stands out prominently. This work delves into the potential of hydrogen fuel for internal combustion engines (ICEs), emphasizing its capacity to ensure the required performance levels while concurrently enhancing overall efficiency. The integration of a mild hybrid powertrain in a small size passenger car was considered for obtaining a twofold advantage: mitigating power loss due to low volumetric efficiency and increasing fuel economy. A comprehensive approach combining 0D/1D modeling simulations and experimental validations was employed on a gasoline-powered small size ICE, considering its conversion to hydrogen, and mild hybridization. Vehicle simulations were performed in AVL Cruise M and validated against experimental data. Various electric motors were scrutinized for a small size battery pack typical of mild hybrid vehicles. Furthermore, the paper assesses the potential range achievable with the hydrogen-powered hybrid vehicle and compares it with the range reported by the manufacturer for the original gasoline and pure electric version. In terms of global results, these modifications were found to successfully improve efficiency compared to baseline gasoline and hydrogen fueling. Additionally, performance gains were achieved, surpassing the capabilities of the original gasoline vehicle despite its intrinsic volumetric efficiency limitations when using hydrogen. Along with the conversion to hydrogen and thus zero-carbon tail-pipe emissions, incorporating a Start/Stop system, and the integration of mild hybrid technology with energy recuperation during braking, overall efficiency was enhanced by up to 30% during urban use. Furthermore, the hybridization implemented in the H2 version allows an autonomy comparable to that of the electric vehicle but with evident shorter refilling times. Specific aspects of the 48 V battery management are also scrutinized.
Real-Time Space Trajectory Judgment for Industrial Robots in Welding Tasks
Authors: Wu Xiangyang , Tian Renyong , Lei Yuncong , Gao Hongli , Fang Yanjiang
Published: May 2024

In welding tasks, the repeated positioning precision of robots can generally reach the micron level, but the data of each axis during each operation may vary. There may even be out-of-control situations where the robot does not run according to the set welding trajectory, which may cause the robot and equipment to collide and be damaged. Therefore, a real-time judgment method for the welding robot trajectory is proposed. Firstly, multiple sets of axis data are obtained by running the welding robot, and the phase of the data is aligned by using a proposed algorithm, and then the Kendall correlation coefficient is used to identify and remove weak axis data. Secondly, the mean of multiple sets of axis data with strong correlation is calculated as the standard trajectory, and the trajectory threshold of the robot is set using the μ ± nσ method based on the trajectory deviation judgment sensitivity. Finally, the absolute difference between the real-time axis trajectory and the standard trajectory is used to determine the deviation of the running trajectory. When the deviation reaches the threshold, a forewarning starts. When the deviation exceeds the threshold + σ, the robot is stopped. Take the six-axis welding robot as an example, by collecting the axis data of the robot running multiple times under the same conditions, it is proved that the proposed method can accurately warn the deviation of the running trajectory. The research results have important practical value for the prevention of welding robot accidents in industrial production.
Distributed Drive Autonomous Vehicle Trajectory Tracking Control Based on Multi-Agent Deep Reinforcement Learning
Authors: Liu Yalei , Ding Weiping , Yang Mingliang , Zhu Honglin , Liu Liyuan , Jin Tianshi
Published: May 2024

In order to enhance the trajectory tracking accuracy of distributed-driven intelligent vehicles, this paper formulates the tasks of torque output control for longitudinal dynamics and steering angle output control for lateral dynamics as Markov decision processes. To dissect the requirements of action output continuity for longitudinal and lateral control, this paper adopts the deep deterministic policy gradient algorithm (DDPG) for longitudinal velocity control and the deep Q-network algorithm (DQN) for lateral motion control. Multi-agent reinforcement learning methods are applied to the task of trajectory tracking in distributed-driven vehicle autonomous driving. By contrasting with two classical trajectory tracking control methods, the proposed approach in this paper is validated to exhibit superior trajectory tracking performance, ensuring that both longitudinal velocity deviation and lateral position deviation of the vehicle remain at lower levels. Compared with classical control methods, the maximum lateral position deviation is improved by up to 90.5% and the maximum longitudinal velocity deviation is improved by up to 97%. Furthermore, it demonstrates excellent generalization and high computational efficiency, and the running time can be reduced by up to 93.7%.
Newtonian Property of Subgradient Method with Optimization of Metric Matrix Parameter Correction
Authors: Tovbis Elena , Krutikov Vladimir , Kazakovtsev Lev
Published: May 2024

The work proves that under conditions of instability of the second derivatives of the function in the minimization region, the estimate of the convergence rate of Newton’s method is determined by the parameters of the irreducible part of the conditionality degree of the problem. These parameters represent the degree of difference between eigenvalues of the matrices of the second derivatives in the coordinate system, where this difference is minimal, and the resulting estimate of the convergence rate subsequently acts as a standard. The paper studies the convergence rate of the relaxation subgradient method (RSM) with optimization of the parameters of two-rank correction of metric matrices on smooth strongly convex functions with a Lipschitz gradient without assumptions about the existence of second derivatives of the function. The considered RSM is similar in structure to quasi-Newton minimization methods. Unlike the latter, its metric matrix is not an approximation of the inverse matrix of second derivatives but is adjusted in such a way that it enables one to find the descent direction that takes the method beyond a certain neighborhood of the current minimum as a result of one-dimensional minimization along it. This means that the metric matrix enables one to turn the current gradient into a direction that is gradient-consistent with the set of gradients of some neighborhood of the current minimum. Under broad assumptions on the parameters of transformations of metric matrices, an estimate of the convergence rate of the studied RSM and an estimate of its ability to exclude removable linear background are obtained. The obtained estimates turn out to be qualitatively similar to estimates for Newton’s method. In this case, the assumption of the existence of second derivatives of the function is not required. A computational experiment was carried out in which the quasi-Newton BFGS method and the subgradient method under study were compared on various types of smooth functions. The testing results indicate the effectiveness of the subgradient method in minimizing smooth functions with a high degree of conditionality of the problem and its ability to eliminate the linear background that worsens the convergence.
Immunostimulatory Effects of Korean Mineral-Rich Seawaters on Cyclophosphamide-Induced Immunosuppression in Mice
Authors: Kim Choong-Gon , Choi Jae Ho , Ku Sae-Kwang , Song Chang-Hyun
Published: May 2024

Deep seawater (DS), obtained from a depth over 200 m, has health benefits due to its rich nutrients and minerals, and intake of DS has shown diverse immunomodulatory effects in allergies and cancer. Therefore, the immunostimulatory effects of Korean mineral-rich seawaters were examined in a cyclophosphamide (CPA)-induced immunosuppression model. Three samples of Korean seawater, namely DS from the East Sea off the coasts of Pohang (PDS) and Uljin (UDS), and seawater from the West Sea off the coast of Boryeong (BS), were collected. The seawaters were abundant in several minerals (calcium, iron, zinc, selenium, etc.). Mice were orally administered the seawaters for 42 days, followed by CPA-induced immunosuppression. The CPA induction reduced the weight of the spleen and lymph nodes; however, the administration of seawaters increased the weight of the lymphoid organs, accompanied by stimulation of natural killer cells’ activity and NF-kB-mediated cytokine production (IFNγ, TNFα, IL1β, IL6, and IL12). The mouse-derived splenocytes showed lymphoproliferation without cytotoxicity in the seawater groups. Histopathological analysis revealed that the seawaters improved the CPA-induced atrophic changes by promoting lymphoproliferation in the spleen and lymph nodes. These results provide useful information for the use of Korean mineral-rich seawaters, particularly PDS and UDS, as alternative immunostimulants under immunosuppressive conditions.
Genomics- and Transcriptomics-Guided Discovery of Clavatols from Arctic Fungi Penicillium sp. MYA5
Authors: Sun Yuan-Yuan , Hu Bo , Yu Hao-Bing , Zhou Jing , Meng Xian-Chao , Ning Zhe , Ding Jin-Feng , Cui Ming-Hui , Liu Xiao-Yu
Published: May 2024

Clavatols exhibit a wide range of biological activities due to their diverse structures. A genome mining strategy identified an A5cla cluster from Penicillium sp. MYA5, derived from the Arctic plant Dryas octopetala, is responsible for clavatol biosynthesis. Seven clavatols, including one new clavatol derivate named penicophenone F (1) and six known clavatols (2–7), were isolated from Penicillium sp. MYA5 using a transcriptome mining strategy. These structures were elucidated by comprehensive spectroscopic analysis. Antibacterial, aldose reductase inhibition, and siderophore-producing ability assays were conducted on compounds 1–7. Compounds 1 and 2 demonstrated inhibitory effects on the ALR2 enzyme with inhibition rates of 75.3% and 71.6% at a concentration of 10 μM, respectively. Compound 6 exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli with MIC values of 4.0 μg/mL and 4.0 μg/mL, respectively. Additionally, compounds 1, 5, and 6 also showed potential iron-binding ability.
Elevated Cardiac Troponin I as a Mortality Predictor in Hospitalised COVID-19 Patients
Authors: Kubiliute Ieva , Urboniene Jurgita , Majauskaite Fausta , Bobkov Edgar , Svetikas Linas , Jancoriene Ligita
Published: May 2024

Background and Objectives: SARS-CoV-2 affects multiple organ systems, including the cardiovascular system, leading to immediate and long-term cardiovascular complications. Acute myocardial injury is one of the earliest and most common cardiac issues in the acute phase of COVID-19. This study aimed to evaluate the prognostic value of cardiac troponin I (cTnI) levels in predicting in-hospital mortality among hospitalised COVID-19 patients. Materials and Methods: A retrospective observational cohort study included 2019 adult patients hospitalised with a confirmed COVID-19 infection stratified by cTnI levels on admission into three groups: <19 ng/L (1416 patients), 19–100 ng/L (431 patients), and >100 ng/L (172 patients). Myocardial injury was defined as blood serum cTnI levels increased above the 99th percentile upper reference limit. Depersonalised datasets were extracted from digital health records. Statistical analysis included multivariable binary logistic and Cox proportional hazards regressions. Results: Overall, 29.87% of patients experienced acute myocardial injury, which development was associated with age, male sex, chronic heart failure, arterial hypertension, obesity, and chronic kidney disease. Among patients with cTnI levels of 19–100 ng/L, the odds ratio for requiring invasive mechanical ventilation was 3.18 (95% CI 2.11–4.79) and, for those with cTnI > 100 ng/L, 5.38 (95% CI 3.26–8.88). The hazard ratio for in-hospital mortality for patients with cTnI levels of 19–100 ng/L was 2.58 (95% CI 1.83–3.62) and, for those with cTnI > 100 ng/L, 2.97 (95% CI 2.01–4.39) compared to patients with normal cTnI levels. Conclusions: Increased cardiac troponin I, indicating myocardial injury, on admission is associated with a more adverse clinical disease course, including a higher likelihood of requiring invasive mechanical ventilation and increased risk of in-hospital mortality. This indicates cardiac troponin I to be a beneficial biomarker for clinicians trying to identify high-risk COVID-19 patients, choosing the optimal monitoring and treatment strategy for these patients.
Aspects of Histopathological and Ultrastructural Retinal Changes in Chronic Exposure to Hydroxychloroquine
Authors: Geamănu Aida , Baciu Ancuţa Elena , Pirvulescu Ruxandra , Iancu Raluca , Anton Nicoleta , Popa-Cherecheanu Alina , Ghita Aurelian Mihai , Romanitan Mihaela Oana
Published: May 2024

Background and Objective: Hydroxychloroquine sulfate (HCQ) is a lysosomotropic agent administered in systemic lupus erythematosus and rheumatoid arthritis that has fewer toxic effects than chloroquine. However, HCQ may still be responsible for retinal toxicity. In this study, we observed structural changes in the retinas of experimental rats after prolonged exposure to HCQ. Matherials and Methods: We investigated several aspects regarding retinal changes, at both the histopathological and ultrastructural levels. We used 96 male albino Wistar rats distributed into four equal groups (n = 24 per group): the first three groups were treated with different doses of HCQ (50, 100, and 200 mg/kg HCQ, injected intraperitoneally in a single dose daily), and the last group (the control group, n = 24) was treated with saline solution administered in the same way (0.4 mL of saline solution). The treated groups received HCQ daily for 4 months, and every month, six animals from each group were sacrificed to assess retinal changes. The eyes were examined via optical (OM) and electronic microscopy (EM). Statistical analysis was deployed, and results regarding retinal morpho-photometry were acquired. Results: We observed structural retinal changes in both high and low doses of HCQ; while high doses determined a significant thinning of the retina, lower doses caused retinal thickening. Morphological retinal changes upon exposure to HCQ are believed to be caused by accumulated HCQ in lysosomes found in retinal ganglion cells and in the inner nuclear and photoreceptor cell layers. Such changes were most evident in the group receiving HCQ intraperitoneally in doses of 100 mg/kg for a longer period (4 months). Conclusions: The present study highlights histopathological and ultrastructural retinal changes induced by chronic HCQ administration, which were strongly connected to the dosage and period of exposure.
Membrane Separation Processes in Wastewater and Water Purification, Volume II
Authors: Giacobbo Alexandre , Bernardes Andréa Moura
Published: May 2024

Water is a crucial natural resource, essential for the development of a range of human activities, from agricultural and industrial to domestic; therefore, its availability is associated with a region or country’s economic growth [...]
Biocompatibility and Corrosion Resistance of Si/ZrO2 Bioceramic Coating on AZ91D Using Electron Beam Physical Vapor Deposition (EB-PVD) for Advanced Biomedical Applications
Authors: Thirugnanasambandam Arunkumar , Gupta Manoj , Murugapandian Rama
Published: May 2024

Herein, ZrO2 and Si + ZrO2 composite coatings on AZ91D alloys are deposited at a constant voltage of 8 kV and 1 Å/s deposition rate using the electron beam physical vapor deposition (EBPVD) method. Further, the samples are examined for surface morphology, phase analysis, adhesion, corrosion, and antibacterial properties, as per ASTM standards. The adhesion strength of the composite (Si + ZrO2) coating nominally dropped (9%) compared to the ZrO2 coating even when the coating thickness increased by 18%. However, the composite (Si + ZrO2) coating improved wettability because silanol promotes hydrogen bonding with water molecules, which elevates the surface energy of the silica and increases its hydrophilic nature. Further, increased wettability and surface roughness have the potential to improve cell adhesion and proliferation. The corrosion potential (Ecorr) values of the coated samples exhibited a positive shift in the potentiodynamic polarization curve, indicating a substantial increase in their corrosion resistance in the artificial blood plasma (ABP) electrolyte. Similarly, SEM images of both coated corroded samples are less affected in the ABP solution, indicating that the coating mitigated heavy cracks and micropores, protecting them from corrosion. The Si + ZrO2 coatings exhibited exceptional performance in preventing bacterial infiltration by Staphylococcus aureus, thus inhibiting the subsequent formation of biofilms. In addition, these coatings demonstrate improved vitality among fibroblast cells, enabling better cellular spreading and proliferation.
Flow-Independent Thermal Conductivity and Volumetric Heat Capacity Measurement of Pure Gases and Binary Gas Mixtures Using a Single Heated Wire
Authors: Kenari Shirin Azadi , Wiegerink Remco J. , Sanders Remco G. P. , Lötters Joost C.
Published: May 2024

Among the different techniques for monitoring the flow rate of various fluids, thermal flow sensors stand out for their straightforward measurement technique. However, the main drawback of these types of sensors is their dependency on the thermal properties of the medium, i.e., thermal conductivity (k), and volumetric heat capacity (ρcp). They require calibration whenever the fluid in the system changes. In this paper, we present a single hot wire suspended above a V-groove cavity that is used to measure k and ρcp through DC and AC excitation for both pure gases and binary gas mixtures, respectively. The unique characteristic of the proposed sensor is its independence of the flow velocity, which makes it possible to detect the medium properties while the fluid flows over the sensor chip. The measured error due to fluctuations in flow velocity is less than ±0.5% for all test gases except for He, where it is ±6% due to the limitations of the measurement setup. The working principle and measurement results are discussed.
Design and Fabrication of Micro/Nano Sensors and Actuators
Authors: Wang Weidong , Yang Ruiguo , Liu Min
Published: May 2024

A micro-electromechanical system (MEMS) is a micro device or system that utilizes large-scale integrated circuit manufacturing technology and microfabrication technology to integrate microsensors, micro-actuators, microstructures, signal processing and control circuits, power supplies, and communication interfaces into one or more chips [...]
Distance Measurement of Contra-Rotating Rotor Blades with Ultrasonic Transducers
Authors: Zhang Shan , Lu Yaohuan , Qiu Zhen , Hu Wenchuan , Dong Zewen , Qiu Zurong , Qiu Yongqiang
Published: May 2024

Coaxial rotor helicopters have great potential in civilian and commercial uses, with many advantages, but challenges remain in the accurate measurement of rotor blades’ distance to prevent blade collision. In this paper, a blade tip distance measurement method based on ultrasonic measurement window and phase triggering is proposed, and the triggering time of the transmitter is studied. Due to the complexity of the measured signal, bandpass filtering and a time-of-flight (TOF) estimation based on the power density of the received signal are utilised. The method is tested on an experimental test platform with a pair of 200 kHz ultrasonic transducers. The experimental results show that the maximum ranging error is less than 1.0% for the blade tip distance in a range of 100–1000 mm. Compared with the amplitude threshold method, the proposed TOF estimation method works well on the received signal with a low SNR and improves the ranging accuracy by about 5 mm when the blade tip distance is larger than 500 mm. This study provides a good reference for the accurate measurement of rotor blade tip distance, and gives a solution for ranging high-speed rotating objects.
Clarifying the Dominant Role of Crystallinity and Molecular Orientation in Differently Processed Thin Films of Regioregular Poly(3-hexylthiophene)
Authors: Gaurav Kumar Vivek , Rai Harshita , Singh Kshitij RB , Sharma Shubham , Ando Yoshito , Pandey Shyam S.
Published: May 2024

Conjugated polymers (CPs) offer the potential for sustainable semiconductor devices due to their low cost and inherent molecular self-assembly. Enhanced crystallinity and molecular orientation in thin films of solution-processable CPs have significantly improved organic electronic device performance. In this work, three methods, namely spin coating, dip coating, and unidirectional floating-film transfer method (UFTM), were utilized with their parametric optimization for fabricating RR-P3HT films. These films were then utilized for their characterization via optical and microstructural analysis to elucidate dominant roles of molecular orientation and crystallinity in controlling charge transport in organic field-effect transistors (OFETs). OFETs fabricated by RR-P3HT thin films using spin coating and dip coating displayed field-effect mobility (μ) of 8.0 × 10−4 cm2V−1s−1 and 1.3 × 10−3 cm2V−1s−1, respectively. This two-time enhancement in µ for dip-coated films was attributed to its enhanced crystallinity. Interestingly, UFTM film-based OFETs demonstrated μ of 7.0 × 10−2 cm2V−1s−1, >100 times increment as compared to its spin-coated counterpart. This superior device performance is attributed to the synergistic influence of higher crystallinity and molecular orientation. Since the crystallinity of dip-coated and UFTM-thin films are similar, ~50 times improved µ of UFTM thin films, this suggests a dominant role of molecular orientation as compared to crystallinity in controlling the charge transport.
Antagonistic Interactions in Onychomycosis: Antifungal Activity of Extracts from Pure and Mixed Cultures of Candida parapsilosis and Trichophyton spp.
Authors: Lemes Thiago Henrique , Nascentes Julyanna Andrade Silva , Regasini Luis Octávio , Siqueira João Paulo Zen , Rigotto Glaucia , Tonani Ludmilla , von Zeska Kress Marcia Regina , de Almeida Margarete Teresa Gottardo
Published: May 2024

Onychomycoses are nail infections that require prolonged therapy and have high recurrence rates. Dermatophytes are the main etiological agents of these infections, followed by yeasts and non-dermatophyte filamentous fungi. The limited antifungal arsenal used to treat onychomycosis and the change in the susceptibility profile of these agents contribute to the chronicity and recalcitrant profile of infections. The present study aimed to determine the antifungal activity of extracts obtained from pure and mixed cultures of Candida parapsilosis, Trichophyton mentagrophytes, and Trichophyton rubrum. Additionally, in vivo toxicity tests with Galleria mellonella and time-kill assays were carried out. The susceptibility profiles of dermatophytes were determined using a microdilution technique with minimum inhibitory concentrations (MICs) between 250 and 8000 µg/mL. The time-kill assay, compared to growth control, resulted in the death of dermatophytes within 48 h. No toxicity of the extracts was detected in experiments with Galleria mellonella larvae under the test conditions. The extracts of pure and mixed cultures of Candida parapsilosis and dermatophytes present antifungal activity against T. mentagrophytes and T. rubrum. Isolating and identifying compounds in the extracts may allow the development of new therapeutic approaches to control fungal infections.
Association between Exposure to Leptospira spp. and Abortion in Mares in Croatia
Authors: Zečević Iva , Picardeau Mathieu , Vince Silvijo , Hađina Suzana , Perharić Matko , Štritof Zrinka , Stevanović Vladimir , Benvin Iva , Turk Nenad , Lohman Janković Ivana , Habuš Josipa
Published: May 2024

Leptospirosis is one of the most common zoonotic infections and a major problem in terms of both veterinary medicine and public health. However, the disease is under-recognised and under-diagnosed worldwide, particularly in horses. Clinical leptospirosis in horses is mainly associated with recurrent uveitis (ERU), which has recently been studied more intensively, and reproductive disorders, the epidemiology of which is still relatively poorly understood. To enhance our comprehension of abortions caused by leptospirosis in horses and to identify the causative strains, a serological study was carried out with subsequent molecular characterisation of the isolate obtained. Using the microscopic agglutination test (MAT), serum samples from mares that aborted and foetal fluids (when available) were tested for antibodies against Leptospira spp. Furthermore, bacteria isolation from kidney cultures was conducted. Of 97 mare serum samples, 21 (21.64%) tested positive, with Grippotyphosa and Pomona being the most frequently detected serogroups. A significantly higher seroprevalence was found in aborting mares compared to the healthy horse population from the same geographical area, as well as a pronounced seasonal variation. Leptospiral antibodies were not detected in any of the foetal fluids, but isolation was successful in 1 case out of 39 (2.56%). Genotyping by multilocus sequence typing (MLST) and core genome multilocus sequence typing (cgMLST) identified the obtained isolate as Leptospira kirschneri, serogroup Pomona, serovar Mozdok. Further surveillance and molecular typing of Leptospira strains causing abortion in horses would be invaluable in understanding the prevalence and impact of leptospirosis on equine reproductive health in Europe.