bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Components with Topology Optimization for Direct Additive Manufacturing by DLMS
Authors: Sedlacek Frantisek , Kalina Tomas , Stepanek Martin
Published: August 2023

This paper presents a novel design methodology that validates and utilizes the results of topology optimization as the final product shape. The proposed methodology aims to streamline the design process by eliminating the need for remodeling and minimizing printing errors through process simulation. It also eliminates the repeated export and import of data between software tools. The study includes a case study involving the steering column housing of a racing car, where Siemens NX Topology Optimization was used for optimization, and verification analysis was conducted using the NX Nastran solver. The final solution was fabricated using AlSi10Mg via direct metal laser sintering on a 3D printer and successfully validated under real conditions. In conclusion, this paper introduces a comprehensive design methodology for the direct utilization of topology optimization, which was validated through a case study, yielding positive results.
Nonlinear Optical Properties of Zn(II) Porphyrin, Graphene Nanoplates, and Ferrocene Hybrid Materials
Authors: Limosani Francesca , Tessore Francesca , Forni Alessandra , Lembo Angelo , Di Carlo Gabriele , Albanese Cecilia , Bellucci Stefano , Tagliatesta Pietro
Published: August 2023

Following some previous work by some of us on the second order nonlinear optical (NLO) properties of Zn(II) meso-tetraphenylporphyrin (ZnP), fullerene, and ferrocene (Fc) diads and triads, in the present research, we explore the NLO response of some new hybrids with two-dimensional graphene nanoplates (GNP) instead of a zero-dimensional fullerene moiety as the acceptor unit. The experimental data, collected by Electric Field Induced Second Harmonic generation (EFISH) technique in CH2Cl2 solution with a 1907 nm incident wavelength, combined with Coupled-Perturbed (CP) and Finite Field (FF) Density Functional Theory (DFT) calculations, show a strongly enhanced contribution of the cubic electronic term γ(−2ω; ω, ω, 0), due to the extended π-conjugation of the carbonaceous acceptor moiety.
Vibration Analysis and Damping Effect of Blade-Hard Coating Composite Structure Based on Base Excitation
Authors: Wang Jiao , Guo Tianyu , Liu Wenyue , Wang Ziwei , Zhang Yuehao
Published: August 2023

Hard coatings are widely employed on blades to enhance impact resistance and mitigate fatigue failure caused by vibration. While previous studies have focused on the dynamic characteristics of beams and plates, research on real blades remains limited. Specifically, there is a lack of investigation into the dynamic characteristics of hard-coated blades under base excitation. In this paper, the finite element model (FEM) of blade-hard coating (BHC) composite structure is established based on finite element methods in which the hard coating (HC) material and the substrate are considered as the isotropic material. Harmonic response analysis is conducted to calculate the resonance amplitude of the composite under base excitation. Numerical simulations and experimental tests are performed to examine the effects of various HC parameters, including energy storage modulus, loss factors, coating thickness, and coating positions, on the dynamic characteristics and vibration reduction of the hard-coated blade composite structures. The results indicate that the difference in natural frequency and modal loss factor of blades increases with higher storage modulus and HC thickness. Moreover, the vibration response of the BHC decreases with higher storage modulus, loss factor, and coating thickness of the HC material. Blades with a complete coating exhibit superior damping effects compared to other coating distributions. These findings are significant for establishing accurate dynamic models of HC composite structures, assessing the effectiveness of HC vibration suppression, and guiding the selection and preparation of HC materials.
A New Reconfigurable Agricultural Vehicle Controlled by a User Graphical Interface: Mechanical and Electronic Aspects
Authors: Kamon Supaphon , di Maria Enrico , Giannoccaro Nicola Ivan , Ishii Kazuo
Published: August 2023

The use of innovative mobile vehicles with increasingly advanced mechatronic aspects in the agricultural sector is becoming, in recent years, a stimulating field of research and comparison. In particular, the problem addressed in the present work refers to improving the locomotion of mobile vehicles on agricultural terrain by reducing the soil damage and improve the overall performance. Agricultural vehicles generally use tracks and wheels for locomotion; the main difference between the two systems is the contact area with the ground and, consequently, the pressure distribution. The present work presents a new reconfigurable agricultural vehicle that can switch from one locomotion system to another, choosing the suitable configuration according to the terrain conditions. All the mechanical and electronic aspects of the prototype developed are analyzed together with an in-depth analysis of the management of the innovative functions through a user-friendly graphical interface able to control the vehicle.
New Physical–Mathematical Analysis of Cardiac Dynamics and Temperature for the Diagnosis of Infectious Disease
Authors: Ramirez Lopez Leonardo Juan , Correa Herrera Sandra Catalina , Lagos Sandoval José Arturo
Published: August 2023

Background: Physical and mathematical theories have made it possible to generate methods for the characterization and diagnosis of physiological variables such as cardiac dynamics. Therefore, it would be useful to implement them to evaluate the dynamic changes in human physiology during the development of COVID-19, which causes disease, severe respiratory and death. Objective: to establish a method for detecting possible alterations associated with COVID-19 through simulations of adult cardiac dynamics and body temperature using dynamic systems theory, probability, entropy and set theory. Methodology: simulations of cardiac dynamics were generated in subjects with 10 temperature ranges between 32 °C and 42 °C via numerical attractors after their evaluation using entropy proportions. Results: differences were observed in the proportions of entropy that differentiate normal cardiac dynamics and acute myocardial infarction towards progression to fever. Conclusion: the physical mathematical analysis of cardiac behavior in relation to body temperature in people with COVID-19 allowed the establishment of a possible surveillance method for detecting minor alterations.
Interactive Internet Framework Proposal of WASPAS Method: A Computational Contribution for Decision-Making Analysis
Authors: Barbara Flavio , dos Santos Marcos , Silva Antônio Sergio , Moreira Miguel Ângelo Lellis , Fávero Luiz Paulo , Pereira Júnior Enderson Luiz , dos Anjos Carvalho Wagner , Muradas Fernando Martins , de Moura Pereira Daniel Augusto , Portella Anderson Gonçalves
Published: August 2023

Concerning the development of computational tools and solutions as a decision-making aid, this paper presents the results of the waspasWEB project, which strives to provide decision-makers with a readily accessible mechanism to employ the weighted aggregated sum product assessment (WASPAS) method. The social contribution of the project encompasses the development of a user-friendly and publicly accessible internet tool, as well as a package launched on the Comprehensive R Archive Network (CRAN) to serve the community of users of the R language. The use of operational research methodologies is crucial to justify decisions, and this effort seeks to advance the adoption of such methodologies, offering managers, researchers, and the general public an intuitive and easily accessible multi-criteria decision-making tool. In this way, we present the technical specifications, usability, and interactivity of the user with the computational platform, being validated its viability through a hypothetical case study. At the end of the research, it exposes the limitations and feasibility of the proposed computational model along with future research.
Spatial Demo-Genetic Predator–Prey Model for Studying Natural Selection of Traits Enhancing Consumer Motility
Authors: Tyutyunov Yuri V.
Published: August 2023

Combining explicit modelling of predator movements with the Kostitzin demo-genetic equations, we study conditions promoting natural selection of consumer motility. The model is a system of partial differential equations describing spatial movements of predators pursuing the diffusing prey. Local predator–prey interactions are described by the classical Rosenzweig–MacArthur model, which additionally accounts for the Allee effect affecting reproduction of predators. Spatial activity of predators is determined by the coefficients of diffusion and indirect prey-taxis. The latter characterizes the predator ability to move directionally up the gradient of taxis stimulus (odor, pheromone, exometabolite) continuously emitted by prey. Assuming that the consumer movement ability is governed by a single diallelic locus with recessive ‘mobile’ and dominant ‘settled’ alleles, the predator population in the model consists of three competing genotypes differing by diffusion and taxis coefficients; other parameters characterizing the genotypes are assumed to be equal. Numerical simulations with different spatial patterns imitating habitat deterioration demonstrate that the direction of selection among the consumer genotypes alternates, depending on the degree of habitat deterioration affecting the overall production of the prey population. Theoretical implications of the results are discussed in relation with problems of biological control, predator interference, and evolution of animal motility.
Joint Optimal Production Planning in Supply Chains under Diverse Low-Carbon Policies
Authors: Hu Chenglin , Bian Junsong , Lai Kin-Keung
Published: August 2023

This paper studies the impact of diverse carbon emission regulations on optimal operation decisions by exploiting the economic production lot model of a multi-manufacturer system in a low-carbon environment. The optimal production planning for multiple enterprises in terms of cost optimization and carbon emission optimization are presented in various scenarios of the fully decentralized system under carbon taxation, cap and trade, and mandatory carbon cap. We prove a unified framework for modeling the scenarios enabled by carbon tax and cap-and-trade policies. Furthermore, the decision vector of the optimal production lot is obtained by analyzing the joint decision scenario based on shared carbon emission caps. We give a comparative analysis of two settings of fully decentralized and carbon quota sharing. The results show that the decision of joint production and stock preparation can reduce the total operational costs of the multi-enterprise system, but the realized carbon emissions may not change or only increase slightly. Our study provides a useful reference for government carbon emission regulation and enterprise operation decision optimization under carbon neutrality and a carbon peak environment.
Sensorless Speed Control for SPMSM Using a Nonlinear Observer and Enhanced Super-Twisting ADRC
Authors: Hu Mingyuan , Ahn Hyeongki , Chung Yoonuh , You Kwanho
Published: August 2023

In this article, a novel strategy called enhanced super-twisting active disturbance rejection control (ESTADRC), as well as a nonlinear observer (NOB), is used to implement a speed control scheme for permanent-magnet synchronous motors with intricate internal dynamics, and it exhibits nonlinearity and variable parameters. A new reaching law is formulated within a super-twisting sliding mode control (STSMC) framework, and a comprehensive procedure for finite convergence time analysis is provided. The convergence region of the state variables of the system is obtained using a Lyapunov function. ESTADRC is developed by integrating STSMC and linear active disturbance rejection control (LADRC), whereas the NOB is employed to estimate the motor’s position or angle value. Simulations demonstrated that the proposed approach is valid and effective compared with super-twisting active disturbance rejection control and LADRC.
An Investigation of Linear Diophantine Fuzzy Nonlinear Fractional Programming Problems
Authors: Iqbal Salma , Yaqoob Naveed , Gulistan Muhammad
Published: August 2023

The linear Diophantine fuzzy set notion is the main foundation of the interactive method of tackling nonlinear fractional programming problems that is presented in this research. When the decision maker (DM) defines the degree α of α level sets, the max-min problem is solved in this interactive technique using Zimmermann’s min operator method. By using the updating technique of degree α, we can solve DM from the set of α-cut optimal solutions based on the membership function and non-membership function. Fuzzy numbers based on α-cut analysis bestowing the degree α given by DM can first be used to classify fuzzy Diophantine inside the coefficients. After this, a crisp multi-objective non-linear fractional programming problem (MONLFPP) is created from a Diophantine fuzzy nonlinear programming problem (DFNLFPP). Additionally, the MONLFPP can be reduced to a single-objective nonlinear programming problem (NLPP) using the idea of fuzzy mathematical programming, which can then be solved using any suitable NLPP algorithm. The suggested approach is demonstrated using a numerical example.
Three Edge-Disjoint Hamiltonian Cycles in Folded Locally Twisted Cubes and Folded Crossed Cubes with Applications to All-to-All Broadcasting
Authors: Pai Kung-Jui
Published: August 2023

All-to-all broadcasting means to distribute the exclusive message of each node in the network to all other nodes. It can be handled by rings, and a Hamiltonian cycle is a ring that visits each vertex exactly once. Multiple edge-disjoint Hamiltonian cycles, abbreviated as EDHCs, have two application advantages: (1) parallel data broadcast and (2) edge fault-tolerance in network communications. There are three edge-disjoint Hamiltonian cycles on n-dimensional locally twisted cubes and n-dimensional crossed cubes while n ≥ 6, respectively. Locally twisted cubes, crossed cubes, folded locally twisted cubes (denoted as FLTQn), and folded crossed cubes (denoted as FCQn) are among the hypercube-variant network. The topology of hypercube-variant network has more wealth than normal hypercubes in network properties. Then, the following results are presented in this paper: (1) Using the technique of edge exchange, three EDHCs are constructed in FLTQ5 and FCQ5, respectively. (2) According to the recursive structure of FLTQn and FCQn, there are three EDHCs in FLTQn and FCQn while n ≥ 6. (3) Considering that multiple faulty edges will occur randomly, the data broadcast performance of three EDHCs in FLTQn and FCQn is evaluated by simulation when 5 ≤ n ≤ 9.
Deep Learning Peephole LSTM Neural Network-Based Channel State Estimators for OFDM 5G and Beyond Networks
Authors: Essai Ali Mohamed Hassan , Abdellah Ali R. , Atallah Hany A. , Ahmed Gehad Safwat , Muthanna Ammar , Koucheryavy Andrey
Published: August 2023

This study uses deep learning (DL) techniques for pilot-based channel estimation in orthogonal frequency division multiplexing (OFDM). Conventional channel estimators in pilot-symbol-aided OFDM systems suffer from performance degradation, especially in low signal-to-noise ratio (SNR) regions, due to noise amplification in the estimation process, intercarrier interference, a lack of primary channel data, and poor performance with few pilots, although they exhibit lower complexity and require implicit knowledge of the channel statistics. A new method for estimating channels using DL with peephole long short-term memory (peephole LSTM) is proposed. The proposed peephole LSTM-based channel state estimator is deployed online after offline training with generated datasets to track channel parameters, which enables robust recovery of transmitted data. A comparison is made between the proposed estimator and conventional LSTM and GRU-based channel state estimators using three different DL optimization techniques. Due to the outstanding learning and generalization properties of the DL-based peephole LSTM model, the suggested estimator significantly outperforms the conventional least square (LS) and minimum mean square error (MMSE) estimators, especially with a few pilots. The suggested estimator can be used without prior information on channel statistics. For this reason, it seems promising that the proposed estimator can be used to estimate the channel states of an OFDM communication system.
Effects of Pera Orange Juice and Moro Orange Juice in Healthy Rats: A Metabolomic Approach
Authors: Fujimori Anderson S. S. , Ribeiro Ana P. D. , Pereira Amanda G. , Dias-Audibert Flávia L. , Tonon Carolina R. , dos Santos Priscila P. , Dantas Danielle , Zanati Silmeia G. , Catharino Rodrigo R. , Zornoff Leonardo A. M. , Azevedo Paula S. , de Paiva Sergio A. R. , Okoshi Marina P. , Lima Estela O. , Polegato Bertha F.
Published: August 2023

Cardiovascular disease is a leading cause of death worldwide. Heart failure is a cardiovascular disease with high prevalence, morbidity, and mortality. Several natural compounds have been studied for attenuating pathological cardiac remodeling. Orange juice has been associated with cardiovascular disease prevention by attenuating oxidative stress. However, most studies have evaluated isolated phytochemicals rather than whole orange juice and usually under pathological conditions. In this study, we evaluated plasma metabolomics in healthy rats receiving Pera or Moro orange juice to identify possible metabolic pathways and their effects on the heart. Methods: Sixty male Wistar rats were allocated into 3 groups: control (C), Pera orange juice (PO), and Moro orange juice (MO). PO and MO groups received Pera orange juice or Moro orange juice, respectively, and C received water with maltodextrin (100 g/L). Echocardiogram and euthanasia were performed after 4 weeks. Plasma metabolomic analysis was performed by high-resolution mass spectrometry. Type I collagen was evaluated in picrosirius red-stained slides and matrix metalloproteinase (MMP)-2 activity by zymography. MMP-9, tissue inhibitor of metalloproteinase (TIMP)-2, TIMP-4, type I collagen, and TNF-α protein expression were evaluated by Western blotting. Results: We differentially identified three metabolites in PO (N-docosahexaenoyl-phenylalanine, diglyceride, and phosphatidylethanolamine) and six in MO (N-formylmaleamic acid, N2-acetyl-L-ornithine, casegravol isovalerate, abscisic alcohol 11-glucoside, cyclic phosphatidic acid, and torvoside C), compared to controls, which are recognized for their possible roles in cardiac remodeling, such as extracellular matrix regulation, inflammation, oxidative stress, and membrane integrity. Cardiac function, collagen level, MMP-2 activity, and MMP-9, TIMP-2, TIMP-4, type I collagen, and TNF-α protein expression did not differ between groups. Conclusion: Ingestion of Pera and Moro orange juice induces changes in plasma metabolites related to the regulation of extracellular matrix, inflammation, oxidative stress, and membrane integrity in healthy rats. Moro orange juice induces a larger number of differentially expressed metabolites than Pera orange juice. Alterations in plasma metabolomics induced by both orange juice are not associated with modifications in cardiac extracellular matrix components. Our results allow us to postulate that orange juice may have beneficial effects on pathological cardiac remodeling.
Suitability of Short- and Long-Term Storage of Volatile Organic Compounds Samples in Syringe-Based Containers: A Comparison Study
Authors: Santos Paulo Henrique Costa , Moura Pedro Catalão , Vassilenko Valentina
Published: August 2023

The employment of advanced analytical techniques and instrumentation enables the tracing of volatile organic compounds (VOCs) in vestigial concentrations (ppbv-pptv range) for several emerging applications, such as the research of disease biomarkers in exhaled air, the detection of metabolites in several biological processes, and the detection of pollutants for air quality control. In this scope, the storage of gaseous samples is crucial for preserving the integrity and stability of the collected set of analytes. This study aims to assess the suitability of three commercially available syringes as air containers (AC) that are commonly used for the collection, storage, isolation, and transportation of samples: glass syringes with glass plungers (AC1), and two plastic syringes, one with plastic plungers (AC2), and one with rubbered plungers (AC3). For this purpose, 99 air samples with different times of storage (from 10 min to 24 h) were analyzed using a Gas Chromatography—Ion Mobility Spectrometry device and the degradation of the samples was properly assessed by comparing the changes in the VOCs’ emission profiles. The quality of the method was assured by via the measurement of the blank’s spectra before each experimental run, as well as by the consecutive measurement of the three replicates for each sample. A statistical analysis of the changes in the VOCs’ emission patterns was performed using principal component analysis (PCA). The results, with a total explained variance of 93.61%, indicate that AC3 is the most suitable option for the long-term storage of air samples. Thus, AC3 containers demonstrated a higher capacity to preserve the stability and integrity of the analytes compared to AC1 and AC2. The findings of the short-term effects analysis, up to 1 h, confirm the suitability of all analyzed syringe-based containers for sample-transferring purposes in onsite analysis.
Haptic Feedback Device Using 3D-Printed Flexible, Multilayered Piezoelectric Coating for In-Car Touchscreen Interface
Authors: Nguyen Van-Cuong , Oliva-Torres Victor , Bernadet Sophie , Rival Guilhem , Richard Claude , Capsal Jean-Fabien , Cottinet Pierre-Jean , Le Minh-Quyen
Published: August 2023

This study focuses on the development of a piezoelectric device capable of generating feedback vibrations to the user who manipulates it. The objective here is to explore the possibility of developing a haptic system that can replace physical buttons on the tactile screen of in-car systems. The interaction between the user and the developed device allows completing the feedback loop, where the user’s action generates an input signal that is translated and outputted by the device, and then detected and interpreted by the user’s haptic sensors and brain. An FEM (finite element model) via ANSYS multiphysics software was implemented to optimize the haptic performance of the wafer structure consisting of a BaTiO3 multilayered piezocomposite coated on a PET transparent flexible substrate. Several parameters relating to the geometric and mechanical properties of the wafer, together with those of the electrodes, are demonstrated to have significant impact on the actuation ability of the haptic device. To achieve the desired vibration effect on the human skin, the haptic system must be able to drive displacement beyond the detection threshold (~2 µm) at a frequency range of 100–700 Hz. The most optimized actuation ability is obtained when the ratio of the dimension (radius and thickness) between the piezoelectric coating and the substrate layer is equal to ~0.6. Regarding the simulation results, it is revealed that the presence of the conductive electrodes provokes a decrease in the displacement by approximately 25–30%, as the wafer structure becomes stiffer. To ensure the minimum displacement generated by the haptic device above 2 µm, the piezoelectric coating is screen-printed by two stacked layers, electrically connected in parallel. This architecture is expected to boost the displacement amplitude under the same electric field (denoted E) subjected to the single-layered coating. Accordingly, multilayered design seems to be a good alternative to enhance the haptic performance while keeping moderate values of E so as to prevent any undesired electrical breakdown of the coating. Practical characterizations confirmed that E=20 V/μm is sufficient to generate feedback vibrations (under a maximum input load of 5 N) perceived by the fingertip. This result confirms the reliability of the proposed haptic device, despite discrepancies between the predicted theory and the real measurements. Lastly, a demonstrator comprising piezoelectric buttons together with electronic command and conditioning circuits are successfully developed, offering an efficient way to create multiple sensations for the user. On the basis of empirical data acquired from several trials conducted on 20 subjects, statistical analyses together with relevant numerical indicators were implemented to better assess the performance of the developed haptic device.
Bacterial Contamination of Mobile Phones Used by Healthcare Workers in Critical Care Units: A Cross-Sectional Study from Saudi Arabia
Authors: Dhayhi Nabil , Kameli Nader , Salawi Mohammed , Shajri Amjad , Basode Vinod Kumar , Algaissi Abdullah , Alamer Edrous , Darraj Majid , Shrwani Khalid , Alhazmi Abdulaziz H.
Published: August 2023

Background: Healthcare-associated infections (HAIs) present a formidable challenge for healthcare institutions, resulting in heightened mortality, morbidity, and economic burden. Within healthcare settings, various equipment and materials, including mobile phones, can potentially act as sources of infection. This study sought to examine the occurrence of bacterial contamination on mobile phones utilized by healthcare workers (HCWs) in intensive care units (ICUs), pediatric intensive care units (PICUs), neonatal intensive care units (NICUs), and cardiac care units (CCUs) within a central hospital (CH) and two peripheral hospitals (PHs) situated in the southwestern province of Saudi Arabia. Materials and methods: We collected a total of 157 samples from mobile phones utilized by HCWs across all ICUs in the CH and PHs. These samples underwent bacteriological analysis to evaluate the degree of bacterial contamination. Results: We found that 45 out of 55 samples from physicians (81.81%) and 58 out of 77 samples from nurses (75.32%) showed bacterial contamination. Contamination rates on HCWs’ mobile phones in the ICU, PICU, and NICU departments of the CH were observed at 69.56%, 80.95%, and 70.27%, respectively. Furthermore, the overall contamination rates in the ICUs, NICUs, and CCUs of the PHs were 78.26%, 88.88%, and 66.66%, respectively. The overall contamination rates of mobile phones in the CH and PHs were 72.11% and 81.13%, respectively. Conclusion: These findings underscore the necessity of routinely disinfecting the mobile phones of HCWs to mitigate the risk of cross-contamination. Implementing robust disinfection protocols can significantly contribute to curtailing the propagation of bacterial pathogens and reducing the incidence of HAIs in healthcare settings.
Prevalence and Clinical Characteristics of Bacterial Pneumonia in Neurosurgical Emergency Center Patients: A Retrospective Study Spanning 13 Years at a Tertiary Center
Authors: Yang Weijian , Yao Haijun , Xi Caihua , Ye Xiangru , Chen Qifang , Zhang Jun , Yu Jian , Hu Jin
Published: August 2023

Patients with brain injuries are at a heightened susceptibility to bacterial pneumonia, and the timely initiation of empiric antibiotic treatment has been shown to substantially reduce mortality rates. Nevertheless, there is a need for knowledge regarding the resistance and prevalence of pulmonary bacterial infections in this patient population. To address this gap, a retrospective study was conducted at a neurosurgical emergency center, focusing on patients with brain injuries. Among the entire patient population, a total of 739 individuals (18.23%) were identified as having bacterial pneumonia, consisting of 1489 strains of Gram-negative bacteria and 205 strains of Gram-positive bacteria. The resistance of Klebsiella pneumoniae to imipenem exhibited a significant increase, rising from 21.74% in 2009 to 96.67% in 2018, and subsequently reaching 48.47% in 2021. Acinetobacter baumannii displayed resistance rates exceeding 80.0% against multiple antibiotics. The resistance profile of Pseudomonas aeruginosa was relatively low. The proportion of Staphylococcus aureus reached its peak at 18.70% in 2016, but experienced a decline to 7.83% in 2021. The abundance of Gram-negative bacteria exceeded that of Gram-positive bacteria by a factor of 5.96. Klebsiella pneumoniae, Acinetobacter baumannii, and Staphylococcus aureus are prominent pathogens characterized by limited antibiotic choices and scarce treatment alternatives for the isolated strains.
Structure and Distribution of the Gold-Related Quartz Vein Systems in the Southwestern Part of the Barberton Greenstone Belt (South Africa, Eswatini)
Authors: Travers Laurine , Chauvet Alain , Lehmann Jérémie
Published: August 2023

This study investigates the structural control of the numerous gold occurrences in the southern part of the Barberton Greenstone Belt in the Malolotja and Steynsdorp areas. The gold-bearing event distribution is studied using field structural geology associated with a petrological and microstructural analysis. Three major tectonic events have been identified in quartz veins and direct country rocks. The first event (De) created a regional schistosity (Se), probably associated with an early thrusting event. The second event (Df) is related to a large-scale folding, which formed the anticline at Steynsdorp and synform at Malolotja. It resulted from a main E–W direction of shortening and is responsible for the folding of the Se schistosity. It formed a N–S-striking axial planar cleavage (Sf), observed and associated with the emplacement of the main gold-bearing veins. The mineralised system exhibits a complex vein network, in which shallow dipping veins have developed coevally with steep west- and east-dipping veins. A third deformation event (Dl) produced by NE–SW shortening is related to the late barren hydrothermal quartz vein formation. Mineralogically, the veins are filled with abundant quartz, and scarce tourmaline and feldspars. Alteration halos composed of neoformed tourmaline and plagioclase within a talc and white mica matrix developed specifically during the late Dl event. A model of regional deformation giving rise to large-scale folds and quartz vein formation formed in response to E–W and NE–SW directions of shortening globally is proposed and discussed in this paper.
Experimental Study on Pore Structure and Soil-Water Characteristic Curve of Ionic Rare Earth Ore under Seepage
Authors: Rao Yunzhang , Zhang Xiaoming , Gao Zhongquan , Xiang Run , Zhang Laiye
Published: August 2023

The ionic rare earth (RE) ore body undergoes particle transport and pore structure change during the leaching process, resulting in "uneven percolation, preferential channel, leaching blind area," and other problems, leading to structural changes in the ore body, low leaching efficiency, and waste of resources. The unsaturated infiltration process is also the key stage that causes these problems. The initial pore structure evolution of the ore body plays a decisive role in the permeability coefficient of the ore body, and the direct influencing factor of the permeability coefficient is the distribution of the pore radius. We carried out research through indoor simulated leaching, the filter paper method for determining matrix suction, and nuclear magnetic resonance (NMR) testing. An ionic rare earth ore soil-water characteristic curve within a large matrix suction range was obtained by the filter paper method. With the increase in volumetric water content, the matrix suction presents a sharp downward trend. When the volumetric water content is less than 20%, this rule is particularly obvious. With the increase in matrix suction, the thickness of the adsorbed water film on the particle surface and pore radius show a decreasing power function trend. Under percolation, the porosity of an ionic rare earth ore sample tends to increase linearly with the increase in volumetric water content during the process from non-saturation to saturation; the porosity of a saturated ore sample after seepage expanded by 17.5 times compared to that of an unsaturated ore sample before seepage. The change rule of the internal microstructure of the ore sample is reflected in the gradual disappearance of micro pores and the gradual formation of small, medium, large, and mega pores, which shows a gradual increase trend. In the pore radius distribution, the more large and medium pores, the larger the permeability coefficient; the more micro and small pores, the smaller the permeability coefficient. For some ore bodies with poor permeability, the ore body is infiltrated with clear water under small water pressure before leaching with a leaching solution, which can improve the permeability of the ore body, effectively improve the efficiency of rare earth leaching, and increase the economic benefits.
Volatile Profile of Strawberry Fruits and Influence of Different Drying Methods on Their Aroma and Flavor: A Review
Authors: Abouelenein Doaa , Acquaticci Laura , Alessandroni Laura , Borsetta Germana , Caprioli Giovanni , Mannozzi Cinzia , Marconi Riccardo , Piatti Diletta , Santanatoglia Agnese , Sagratini Gianni , Vittori Sauro , Mustafa Ahmed M.
Published: August 2023

Strawberries are the most popular berry fruit in the world, due to their distinctive aroma, flavor, and known health properties. Because volatile substances play a large role in strawberry flavor, even little alterations can have a big impact on how the fruit tastes. Strawberries are thought to have a complex aroma. Fresh strawberry fruits contain more than 360 volatile compounds, including esters, furans, terpenes, alcohols, aldehydes, ketones, and sulfur compounds. Despite having far lower concentrations than esters, terpenoids, furanones, and sulfur compounds, all have a considerable impact on how people perceive the aroma of strawberries. With a focus on the active aroma components and the many analytical methods used to identify them, including gas chromatography, electronic nose sensing, and proton-transfer- reaction mass spectrometry, the present review’s aim was to provide a summary of the relevant literature. Additionally, strawberry fruits are frequently dried to create a powder in order to increase their shelf life. Consequently, the impact of various drying techniques on strawberries’ volatile profile was investigated in the current review. This review can be considered a good reference for research concerning the aroma profile of strawberries. It helps to better understand the complex aroma and flavor of strawberries and provides a guide for the effects of drying processing.
Immunomodulatory Effect of Flammulina rossica Fermentation Extract on Healthy and Immunosuppressed Mice
Authors: Dai Yingdi , Ma Sijia , Zhu Yanyan , Gontcharov Andrey A. , Liu Yang , Wang Qi
Published: August 2023

Flammulina rossica fermentation extract (FREP) was obtained by ethanol precipitation of the fermentation broth. The molecular weight of FREP is 28.52 kDa, and it mainly contains active ingredients such as polysaccharides, proteins, reducing sugars, and 16 amino acids. Among them, the polysaccharides were mannose, glucose, galactose, arabinose, and fucose and possessed β-glycosidic bonds. Furthermore, the immunoregulatory activities of FREP were investigated in vivo. The results demonstrated that FREP could increase the counts of CD4+ T lymphocytes and the ratio of CD4+/CD8+ in a dose-dependent manner in healthy mice. In addition, FREP significantly increased serum cytokines, including IL-2, IL-8, IL-10, IL-12, IL-6, IL-1β, INF-γ, C-rection protein, and TNF-α, and promoted splenocyte proliferation in healthy mice. Finally, FREP could restore the counts of white blood cells, red blood cells, secretory immunoglobulin A, and antibody-forming cells and significantly promote the serum haemolysin level in mice treated with cyclophosphamide. The findings indicated that FREP possessed immunoregulatory activity in healthy mice and could improve the immune functions in immunosuppressive mice. Therefore, FREP could be exploited as an immunomodulatory agent and potential immunotherapeutic medicine for patients with inadequate immune function.
In Silico and In Vitro Studies of 4-Hydroxycoumarin-Based Heterocyclic Enamines as Potential Anti-Tumor Agents
Authors: Assad Mediha , Paracha Rizwan Nasir , Siddique Abu Bakar , Shaheen Muhammad Ashraf , Ahmad Nadeem , Mustaqeem Muhammad , Kanwal Fariha , Mustafa Muhammad Zia Ul , Rehman Muhammad Fayyaz ur , Fatima Sumaya , Lu Changrui
Published: August 2023

The present study reports the one-step synthesis of several 3-formyl-4-hydroxycouramin-derived enamines (4a–4i) in good yields (65–94%). The characterization of the synthesized compounds was carried out via advanced analytical and spectroscopic techniques, such as melting point, electron impact mass spectrometry (EI-MS), 1H-NMR, 13C-NMR, elemental analysis, FTIR, and UV-Visible spectroscopy. The reaction conditions were optimized, and the maximum yield was obtained at 3–4 h of reflux of the reactants, using 2-butanol as a solvent. The potato disc tumor assay was used to assess Agrobacterium tumefaciens-induced tumors to evaluate the anti-tumor activities of compounds (4a–4i), using Vinblastine as a standard drug. The compound 4g showed the lowest IC50 value (1.12 ± 0.2), which is even better than standard Vinblastine (IC50 7.5 ± 0.6). For further insight into their drug actions, an in silico docking of the compounds was also carried out against the CDK-8 protein. The binding energy values of compounds were found to agree with the experimental results. The compounds 4g and 4h showed the best affinities toward protein, with a binding energy value of −6.8 kcal/mol.
Ultrafast Transient Absorption Spectra and Kinetics of Rod and Cone Visual Pigments
Authors: Krishnamoorthi Arjun , Khosh Abady Keyvan , Dhankhar Dinesh , Rentzepis Peter M.
Published: August 2023

Rods and cones are the photoreceptor cells containing the visual pigment proteins that initiate visual phototransduction following the absorption of a photon. Photon absorption induces the photochemical transformation of a visual pigment, which results in the sequential formation of distinct photo-intermediate species on the femtosecond to millisecond timescales, whereupon a visual electrical signal is generated and transmitted to the brain. Time-resolved spectroscopic studies of the rod and cone photo-intermediaries enable the detailed understanding of initial events in vision, namely the key differences that underlie the functionally distinct scotopic (rod) and photopic (cone) visual systems. In this paper, we review our recent ultrafast (picoseconds to milliseconds) transient absorption studies of rod and cone visual pigments with a detailed comparison of the transient molecular spectra and kinetics of their respective photo-intermediaries. Key results include the characterization of the porphyropsin (carp fish rhodopsin) and human green-cone opsin photobleaching sequences, which show significant spectral and kinetic differences when compared against that of bovine rhodopsin. These results altogether reveal a rather strong interplay between the visual pigment structure and its corresponding photobleaching sequence, and relevant outstanding questions that will be further investigated through a forthcoming study of the human blue-cone visual pigment are discussed.
Natural Products from Singapore Soil-Derived Streptomycetaceae Family and Evaluation of Their Biological Activities
Authors: Chin Elaine-Jinfeng , Ching Kuan-Chieh , Tan Zann Y. , Wibowo Mario , Leong Chung-Yan , Yang Lay-Kien , Ng Veronica W. P. , Seow Deborah C. S. , Kanagasundaram Yoganathan , Ng Siew-Bee
Published: August 2023

Natural products have long been used as a source of antimicrobial agents against various microorganisms. Actinobacteria are a group of bacteria best known to produce a wide variety of bioactive secondary metabolites, including many antimicrobial agents. In this study, four actinobacterial strains found in Singapore terrestrial soil were investigated as potential sources of new antimicrobial compounds. Large-scale cultivation, chemical, and biological investigation led to the isolation of a previously undescribed tetronomycin A (1) that demonstrated inhibitory activities against both Gram-positive bacteria Staphylococcus aureus (SA) and methicillin-resistant Staphylococcus aureus (MRSA) (i.e., MIC90 of 2–4 μM and MBC90 of 9–12 μM), and several known antimicrobial compounds, namely nonactin, monactin, dinactin, 4E-deacetylchromomycin A3, chromomycin A2, soyasaponin II, lysolipin I, tetronomycin, and naphthomevalin. Tetronomycin showed a two- to six-fold increase in antibacterial activity (i.e., MIC90 and MBC90 of 1–2 μM) as compared to tetronomycin A (1), indicating the presence of an oxy-methyl group at the C-27 position is important for antibacterial activity.
Factors Influencing the Repeated Transient Optical Droplet Vaporization Threshold and Lifetimes of Phase Change, Perfluorocarbon Nanodroplets
Authors: Zhao Andrew X. , Zhu Yiying I. , Chung Euisuk , Lee Jeehyun , Morais Samuel , Yoon Heechul , Emelianov Stanislav
Published: August 2023

Perfluorocarbon nanodroplets (PFCnDs) are sub-micrometer emulsions composed of a surfactant-encased perfluorocarbon (PFC) liquid and can be formulated to transiently vaporize through optical stimulation. However, the factors governing repeated optical droplet vaporization (ODV) have not been investigated. In this study, we employ high-frame-rate ultrasound (US) to characterize the ODV thresholds of various formulations and imaging parameters and identify those that exhibit low vaporization thresholds and repeatable vaporization. We observe a phenomenon termed “preconditioning”, where initial laser pulses generate reduced US contrast that appears linked with an increase in nanodroplet size. Variation in laser pulse repetition frequency is found not to change the vaporization threshold, suggesting that “preconditioning” is not related to residual heat. Surfactants (bovine serum albumin, lipids, and zonyl) impact the vaporization threshold and imaging lifetime, with lipid shells demonstrating the best performance with relatively low thresholds (21.6 ± 3.7 mJ/cm2) and long lifetimes (t1/2 = 104 ± 21.5 pulses at 75 mJ/cm2). Physiological stiffness does not affect the ODV threshold and may enhance nanodroplet stability. Furthermore, PFC critical temperatures are found to correlate with vaporization thresholds. These observations enhance our understanding of ODV behavior and pave the way for improved nanodroplet performance in biomedical applications.
Gait Analysis, Metabolic Parameters and Adherence to the Mediterranean Diet in Patients with Type 2 Diabetes Mellitus Compared with Healthy Controls: A Pilot Study
Authors: Efthymiou Dimitris , Katsiki Niki , Zekakos Dimitrios Xipolias , Vassiliadis Panagiotis , Petrelis Alexandros , Vassilopoulou Emilia
Published: August 2023

Background and purpose: Patients with type 2 diabetes mellitus (T2DM) are prone to developing diabetic peripheral neuropathy (DPN) with an increased risk of injuries while walking, potentially leading to plantar ulcers. We aimed to assess the early gait changes in T2DM patients without clinical signs of DPN in comparison to age-matched healthy controls (HC). Subjects and Methods: One hundred T2DM patients (78 women, mean age: 66.4 ± 11.5 years) and 50 age-matched HC (34 women, mean age 62.1 ± 7.9 years) were evaluated with the PODOSmart® gait analysis device. Anthropometric and biochemical data, as well as dietary habits were collected for all participants. T2DM patients also completed the Diabetes Distress (DS) self-report validated questionnaire. Results: One patient was excluded from the study due to lack of recent biochemical data. Among the T2DM patients, 88.9% reported little or no DS and 11.1% moderate DS. The T2DM group had higher body mass index, waist circumference, systolic blood pressure, glycated hemoglobin A1c, sodium, white blood cell count, triglycerides and low-density lipoprotein cholesterol, but lower high-density lipoprotein cholesterol than HC (p < 0.05 for all comparisons). The MedDiet score was satisfactory in both groups (p > 0.05). Significant differences were found between the two study groups in gaitline heel off, propulsion speed, foot progression angle, time taligrade phase, stride length, walking speed, angle attack, oscillation speed, pronation-supination toe off and clearance. Conclusions: The T2DM patients without self-reported DS or clinical signs of DPN may exhibit significant differences in several gait parameters analyzed with PODOSmart®. Whether gait analysis can be used as an early diagnostic tool of T2DM complications should be further explored.
The Joint Effects of Bisphenols and Iodine Exposure on Thyroid during Pregnancy
Authors: Lu Wei , Sun Zhuo , Wang Zhengyuan , Qu Mengying , Shi Zehuan , Song Qi , Shen Liping , Mai Shupeng , Wang Yuan , Hong Xinyu , Zang Jiajie
Published: August 2023

The aim of this research was to study the combined effects of bisphenols and iodine exposure on the thyroid gland during pregnancy. We included 162 pregnant women from a cohort established in Shanghai. Urinary concentrations of bisphenol A, bisphenol B(BPB), bisphenol C(BPC), bisphenol F, bisphenol S, and bisphenol AF(BPAF) were examined. Bayesian kernel machine regression (BKMR) and quantile g-computation models were used. The geometric means of BPA, BPB, BPC, BPF, BPS, BPAF, and ΣBPs levels in urine were 3.03, 0.24, 2.66, 0.36, 0.26, 0.72, and 7.55 μg/g creatinine, respectively. We observed a positive trend in the cumulative effects of BPs and iodine on serum triiodothyronine (FT3) and free thyroxine (FT4), as well as a U-shaped dose–response relationship between BPs and the probability of occurrence of thyroperoxidase autoantibody positivity in women with low urinary iodine concentration. In addition, a synergistic effect on the probability of occurrence of thyroid autoantibody positivity was observed between BPF and BPB, as well as between BPC and BPAF in this study. There were adverse health effects on the thyroid after co-exposure to BPs and iodine. Even if pregnant women were exposed to lower levels of BPs, women with iodine deficiency remained vulnerable to thyroid autoimmune disease.
The Effects of Social Distance and Front-of-Package Claims on Healthy Food Selection: Moderating Role of Perceived Importance of Eating Healthily
Authors: Chattaraman Veena , Lee Yee Ming , Robinson Ebony Marchelle , Book Adam J. , Al-Amin Fnu
Published: August 2023

Applying construal level theory, this study examined how social distance (thinking of self/children), front-of-package (FOP) claim type (nutrient/health/control), and perceived importance of eating healthily (low/high) impact consumer responses (attitudes/purchase intent) to healthier food products through an online experiment with 171 U.S. parents from low-to-mid socio-economic households. Participants were randomly assigned to view controlled images of healthier foods with packaging that bore different claim types for real and fictitious brands. Results revealed that when choosing for themselves, consumer attitudes were more positive when the healthier food package carried a nutrient (vs. health) claim, however, control claims received the most positive evaluations. When choosing for children, attitudes were more positive when the package carried a health (vs. nutrient/control) claim. Attitudes toward healthier foods were higher for consumers with high (vs. low) perceived importance of eating healthily when the package bore a nutrient claim, however, their attitudes did not significantly differ when the package bore a health/control claim. Purchase intent for healthier foods was higher for consumers with high (vs. low) perceived importance of healthy eating when shopping for self; whereas, when shopping for children, purchase intent did not significantly differ between consumers who varied in perceived importance of eating healthily.