bluuebunny/crossref_metadata_2025 huggingface dataset:
The Evaluation of Interface Quality in HfO2 Films Probed by Time-Dependent Second-Harmonic Generation
Authors: Zhang Libo , Ye Li , Zhao Weiwei , Huang Chongji , Liu Xue , Gao Wenshuai , Li Tao , Min Tai , Yang Jinbo , Tian Mingliang , Chen Xuegang
Published: July 2024

Time-dependent second-harmonic generation (TD-SHG) is an emerging sensitive and fast method to qualitatively evaluate the interface quality of the oxide/Si heterostructures, which is closely related to the interfacial electric field. Here, the TD-SHG is used to explore the interface quality of atomic layer deposited HfO2 films on Si substrates. The critical SHG parameters, such as the initial SHG signal and characteristic time constant, are compared with the fixed charge density (Qox) and the interface state density (Dit) extracted from the conventional electrical characterization method. It reveals that the initial SHG signal linearly decreases with the increase in Qox, while Dit is linearly correlated to the characteristic time constant. It verifies that the TD-SHG is a sensitive and fast method, as well as simple and noncontact, for evaluating the interface quality of oxide/Si heterostructures, which may facilitate the in-line semiconductor test.
Hydrogels for Neural Regeneration: Exploring New Horizons
Authors: Omidian Hossein , Chowdhury Sumana Dey , Cubeddu Luigi X.
Published: July 2024

Nerve injury can significantly impair motor, sensory, and autonomic functions. Understanding nerve degeneration, particularly Wallerian degeneration, and the mechanisms of nerve regeneration is crucial for developing effective treatments. This manuscript reviews the use of advanced hydrogels that have been researched to enhance nerve regeneration. Hydrogels, due to their biocompatibility, tunable properties, and ability to create a supportive microenvironment, are being explored for their effectiveness in nerve repair. Various types of hydrogels, such as chitosan-, alginate-, collagen-, hyaluronic acid-, and peptide-based hydrogels, are discussed for their roles in promoting axonal growth, functional recovery, and myelination. Advanced formulations incorporating growth factors, bioactive molecules, and stem cells show significant promise in overcoming the limitations of traditional therapies. Despite these advancements, challenges in achieving robust and reliable nerve regeneration remain, necessitating ongoing research to optimize hydrogel-based interventions for neural regeneration.
Pressure-Induced Exciton Formation and Superconductivity in Platinum-Based Mineral Sperrylite
Authors: Wang Limin , Hu Rongwei , Anand Yash , Saha Shanta R. , Jeffries Jason R. , Paglione Johnpierre
Published: July 2024

We report a comprehensive study of Sperrylite (PtAs2), the main platinum source in natural minerals, as a function of applied pressures up to 150 GPa. While no structural phase transition is detected from pressure-dependent X-ray measurements, the unit cell volume shrinks monotonically with pressure following the third-order Birch–Murnaghan equation of state. The mildly semiconducting behavior found in pure synthesized crystals at ambient pressures becomes more insulating upon increasing the applied pressure before metalizing at higher pressures, giving way to the appearance of an abrupt decrease in resistance near 3 K at pressures above 92 GPa consistent with the onset of a superconducing phase. The pressure evolution of the calculated electronic band structure reveals the same physical trend as our transport measurements, with a non-monotonic evolution explained by a hole band that is pushed below the Fermi energy and an electron band that approaches it as a function of pressure, both reaching a touching point suggestive of an excitonic state. A Lifshitz transition of the electronic structure and an increase in the density of states may naturally explain the onset of superconductivity in this material.
An Approach to Improve Specimen Processing for the Flexural Strength Testing of Zirconia
Authors: Pandey Nashib , Karlin Sabrina , Bornstein Michael Marc , Rohr Nadja
Published: July 2024

Measuring the flexural strength of restorative materials such as zirconia is crucial for providing proper indications for clinical applications and predicting performance. Great variations in specimen preparation for flexural strength measurements exist among laboratories. The aim was to evaluate how the processing method, surface treatment, and test method of the specimens affect the flexural strength of zirconia. Zirconia specimens (VITA YZ HT) (n = 270) were processed using CAD/CAM or were conventionally milled with three different surface treatments (machined, ground, polished) and were measured with three-point bending (non-chamfered/chamfered) or biaxial flexural strength test. Weibull statistics were conducted. The mean flexural strength values ranged from 612 MPa (conventional, machined, three-point bending non-chamfered) to 1143 MPa (CAD/CAM, polished, biaxial flexural strength). The highest reliability is achieved when specimens are prepared using thoroughly controllable processing with CAD/CAM and subsequently polished. Higher strength values are achieved with the biaxial flexural strength test method because the stress concentration in relation to the effective volume is smaller. Polishing reduces surface microcracks and therefore increases the strength values.
Influence of FexOy and Al2O3 Contents on the Thermal Stability of Iron Ore-Waste Fibers: Key Mechanisms and Control
Authors: Li Xiaoguang , Wang Xiaohui , Fang Xianju , Shen Xianglong , Huang Liding , Qin Jinyi , Fu Wanzhang , Li Weiguang
Published: July 2024

Traditional rock wool fibres are susceptible to crystallization and pulverization. To mitigate this, glass fibres were produced from iron ore waste (IOW). When the ratio of Fe2+ and Fe3+ is 1:3 and the Al2O3 content is 10 wt.%, increasing the FexOy content enhances the thermal stability.At an FexOy content of 17–19% and an Al2O3 content of 10–13%, the glass transition temperature (Tg) peaked. Increasing the FexOy content from 10% to 20% enhanced the stability of Si-O and Al-O bonds and increased bridged oxygen, stabilizing the structure. Here, Fe2+ balances structural charges, while Fe3+ replaces some Al atoms in the network. When the Al2O3 content is 10–13% and the FexOy content is 17–19%, the thermal stability of the IOW rock glass reaches its optimal level. At 20% FexOy content, the structure becomes three-dimensional and cyclic, increasing polymerization. Consequently, incorporating FexOy alongside a 10% Al2O3 content improves thermal stability, supporting the development of high-stability rock wool from IOW. This approach also enhances the refractory properties of rock wool fibres within the FexOy-Al2O3-SiO2-MgO-CaO system.
Stress-Corrosion-Cracking Sensitivity of the Sub-Zones in X80 Steel Welded Joints at Different Potentials
Authors: Zhang Ci , He Yinsheng , Zheng Wenyue
Published: July 2024

X80 steel plays a pivotal role in the development of oil and gas pipelines; however, its welded joints, particularly the heat-affected zone (HAZ), are susceptible to stress corrosion cracking (SCC) due to their complex microstructures. This study investigates the SCC initiation mechanisms of X80 steel welded joints under practical pipeline conditions with varying levels of cathodic protection. The SCC behaviors were analyzed through electrochemical measurements, hydrogen permeation tests, and interrupted slow strain rate tensile tests (SSRTs) conducted in a near-neutral pH environment under different potential conditions (OCP, −1.1 VSCE, −1.2 VSCE). These behaviors were influenced by microstructure type, grain size, martensite/austenite (M/A) constituents, and dislocation density. The sub-zones of the weld exhibited differing SCC resistance, with the fine-grain (FG) HAZ, base metal (zone), welded metal (WM) zone, and coarse-grain (CG) HAZ in descending order. In particular, the presence of coarse grains, low dislocation density, and extensive M/A islands collectively increased corrosion susceptibility and SCC sensitivity in the CGHAZ compared to other sub-zones. The SCC initiation mechanisms of the sub-zones within the X80-steel welded joint were primarily anodic dissolution (AD) under open-circuit potential (OCP) condition, shifting to either hydrogen-enhanced local plasticity (HELP) or hydrogen embrittlement (HE) mechanisms at −1.1 VSCE or −1.2 VSCE, respectively.
Effect of Mo Content on the Structural, Mechanical, and Tribological Properties of New Zr-Nb-Mo Alloys Obtained by Combining Powder Metallurgy and Vacuum Arc Melting Methods
Authors: Zając Julia , Matuła Izabela , Barylski Adrian , Aniołek Krzysztof , Nabiałek Marcin , Flesińska Julia , Dercz Grzegorz
Published: July 2024

Considering the high demand for innovative solutions in medicine, a major increase in interest in biomaterials research has been noticed, with the most significant advancements in metals and their alloys. Titanium-based alloys are one of the most recognised in the scientific community but do not represent the only way to achieve optimal results. Zirconium alloys for medical applications are a novelty with significant research potential based on their outstanding properties, which may be of value for medicine. The aim of the present study was to obtain new biomedical Zr-Nb-Mo alloys with varying ratios of their respective elements—Zr and Mo—using combined powder metallurgy (PM) and arc melting (VAM) methods. The obtained samples underwent microstructure analysis using an optical microscope (OM) and a scanning electron microscope (SEM). The study of element distribution was conducted with energy dispersive spectroscopy (EDS), whereas the phase composition was determined using X-ray diffraction (XRD). Mechanical properties were examined with a Micro Combi Tester MCT3, whereas tribological properties were assessed with a TRN Tribometer, and Ringer’s solution was used as a lubricant. Additionally, the wear tracks of the studied samples were observed using the SEM. The research results indicated that increased Mo content conduced to microstructure refinement and homogeneity. Furthermore, the higher content of this element contributed to the growth of the HVIT, HIT, and EIT parameters, together with the improvement in the tribological performance of the alloys. XRD analysis revealed that the obtained samples were multiphase, and raising the Mo addition promoted the formation of new phases, including a ternary phase—Zr0.9Nb0.66Mo1.44 (Fd3¯m). The chemical composition study showed uneven distribution of niobium and areas of uneven mutual distribution of zirconium and molybdenum.
Kinetic Study and Catalytic Activity of Cr3+ Catalyst Supported on Calcium Silicate Hydrates for VOC Oxidation
Authors: Sidaraite Ramune , Baltakys Kestutis , Jaskunas Andrius , Naslenas Nedas , Slavinskas Darius , Slavinskas Edvinas , Dambrauskas Tadas
Published: July 2024

Volatile organic compounds (VOCs) are pollutants that pose significant health and environmental risks, necessitating effective mitigation strategies. Catalytic oxidation emerges as a viable method for converting VOCs into non-toxic end products. This study focuses on synthesizing a catalyst based on calcium silicate hydrates with chromium ions in the CaO-SiO2-Cr(NO3)3-H2O system under hydrothermal conditions and evaluating its thermal stability and catalytic performance. A catalyst with varying concentrations of chromium ions (10, 25, 50, 100 mg/g Cr3+) was synthesized in unstirred suspensions under saturated steam pressure at a temperature of 220 °C. Isothermal curing durations were 8 h, 16 h, and 48 h. Results of X-ray diffraction and atomic absorption spectroscopy showed that hydrothermal synthesis is effective for incorporating up to 100 mg/g Cr3+ into calcium silicate hydrates. The catalyst with Cr3+ ions (50 mg/g) remained stable up to 550 °C, beyond which chromatite was formed. Catalytic oxidation experiments with propanol and propyl acetate revealed that the Cr3+ catalyst supported on calcium silicate hydrates enhances oxygen exchange during the heterogeneous oxidation process. Kinetic calculations indicated that the synthesized catalyst is active, with an activation energy lower than 65 kJ/mol. This study highlights the potential of Cr3+-intercalated calcium silicate hydrates as efficient catalysts for VOC oxidation.
A Copper Silicate-Based Multifunctional Nanoplatform with Glutathione Depletion and Hypoxia Relief for Synergistic Photodynamic/Chemodynamic Therapy
Authors: Shao Meiqi , Zhang Wei , Wang Fu , Wang Lan , Du Hong
Published: July 2024

Chemodynamic therapy (CDT) alone cannot achieve sufficient therapeutic effects due to the excessive glutathione (GSH) and hypoxia in the tumor microenvironment (TME). Developing a novel strategy to improve efficiency is urgently needed. Herein, we prepared a copper silicate nanoplatform (CSNP) derived from colloidal silica. The Cu(II) in CSNP can be reduced to Cu(I), which cascades to induce a subsequent CDT process. Additionally, benefiting from GSH depletion and oxygen (O2) generation under 660 nm laser irradiation, CSNP exhibits both Fenton-like and hypoxia-alleviating activities, contributing to the effective generation of superoxide anion radical (•O2−) and hydroxyl radical (•OH) in the TME. Furthermore, given the suitable band-gap characteristic and excellent photochemical properties, CSNP can also serve as an efficient type-I photosensitizer for photodynamic therapy (PDT). The synergistic CDT/PDT activity of CSNP presents an efficient antitumor effect and biosecurity in both in vitro and in vivo experiments. The development of an all-in-one nanoplatform that integrates Fenton-like and photosensing properties could improve ROS production within tumors. This study highlights the potential of silicate nanomaterials in cancer treatment.
Research on Improving Moisture Resistance of Asphalt Mixture with Compounded Recycled Metallurgical Slag Powders
Authors: Gao Bo , Xu Haiqin , Wu Shaopeng , Wang Huan , Yang Xinkui , Chen Pengrui
Published: July 2024

The utilization of steel slag as an alternative material in asphalt mixtures is considered the solution to the problem of the shortage of natural aggregates. However, asphalt mixtures with steel slag show susceptibility to damage caused by moisture, especially in powder form. Therefore, blast furnace slag powders were used to compound with steel slag powders as fillers to improve the moisture resistance of asphalt mixtures. The characteristics of the steel slag powders and blast furnace slag powders were investigated initially. Subsequently, the adhesion properties of the asphalt mastics with the powders to the aggregates were evaluated. Finally, the moisture resistances of the asphalt mixtures were identified. The results indicate that the steel slag powder exhibited a notable prevalence of surface pores, which had a more uniform size distribution. In contrast, the blast furnace slag powder exhibited a greater average pore size. The larger specific surface area of the steel slag powder was over 30% larger than that of the blast furnace slag powder, and the superior gelling activity of the blast furnace powder enhanced the adhesion property. Both the steel slag powder and blast furnace slag powder were found to enhance the adhesion properties of the asphalt mastics, while the effect of the steel slag powder was more pronounced, the maximum force difference of which exceeded 200 N. The antagonistic effect of the steel slag powder and blast furnace slag powder on the resistance of the adhesive interface to moisture damage was confirmed by the contact angle test. The incorporation of the blast furnace slag powder markedly enhanced the moisture resistances of the asphalt mixtures. The phenomenon of dynamic moisture damage to the asphalt mixtures was more pronounced under the multicycle times, obviously severer than that in a stable water environment. As the dynamic moisture cycles increased, the degree of destruction gradually approached a steady state.
Mechanism Study on the Effect of Surface Electrical Property on Microbial Membrane Formation Efficiency of TiO2-SiC Composite Filler in Recirculating Aquaculture System
Authors: Li Jiaxin , Hong Ze , Ouyang Jingying , Zheng Han , Liu Ying
Published: July 2024

Recirculating aquaculture systems (RASs) offer significant advantages in aquaculture by markedly decreasing water usage and increasing culture density. A vital component within a RAS is the filler material, which serves as a surface for microbial colonization. Effective microbial treatment is crucial for the efficient operation of a RAS as it assists in purifying the wastewater generated within the system. Nevertheless, traditional fillers often show low efficiency in biofilm formation. The commercial silicon carbide used in this study is a foam ceramic filter with a density of about 0.4–0.55 g/cm3, a number of holes of about 10, and a through porosity of 80.9%, with a diameter of about 5 cm. This research investigates the utilization of a titanium dioxide–silicon carbide (TiO2-SiC) composite filler to improve the purification efficiency of ammonia nitrogen and chemical oxygen demand (COD) in aquaculture wastewater. The study involved the application of titanium dioxide films onto the surface of silicon carbide to produce the composite filler. This method takes advantage of the dipole interaction between titanium dioxide and microorganisms, which enhances biofilm culturing efficiency on the silicon carbide surface. The performance of three different fillers was assessed for their ability to purify aquaculture wastewater. Results showed that the TiO2-SiC composite filler was 1.67 times more effective in removing COD and 1.07 times more effective in removing ammonia nitrogen compared to using silicon carbide alone. These results demonstrate that the incorporation of a titanium dioxide coating substantially boosts the microbial colonization efficiency of silicon carbide, thereby enhancing the overall wastewater purification efficiency in RAS.
Examining the Workability, Mechanical, and Thermal Characteristics of Eco-Friendly, Structural Self-Compacting Lightweight Concrete Enhanced with Fly Ash and Silica Fume
Authors: Akbulut Zehra Funda , Yavuz Demet , Tawfik Taher A. , Smarzewski Piotr , Guler Soner
Published: July 2024

This study compares the workability, mechanical, and thermal characteristics of structural self-compacting lightweight concrete (SCLWC) formulations using pumice aggregate (PA), expanded perlite aggregate (EPA), fly ash (FA), and silica fume (SF). FA and SF were used as partial substitutes for cement at a 10% ratio in various mixes, impacting different aspects: According to the obtained results, FA enhanced the workability but SF reduced it, while SF improved the compressive and splitting tensile strengths more than FA. EPA, used as a fine aggregate alongside PA, decreased the workability, compressive strength, and splitting tensile strength compared to the control mix (K0). The thermal properties were altered by FA and SF similarly, while EPA notably reduced the thermal conductivity coefficients. The thermal conductivity coefficients (TCCs) of the K0–K4 SCLWC mixtures ranged from 0.275 to 0.364 W/mK. K0 had a TCC of 0.364 W/mK. With 10% FA, K1 achieved 0.305 W/mK; K2 with 10% SF reached 0.325 W/mK. K3 and K4, using EPA instead of PA, showed significantly lower TCC values: 0.275 W/mK and 0.289 W/mK, respectively. FA and SF improved the thermal conductivity compared to K0, while EPA further reduced the TCC values in K3 and K4 compared to K1 and K2. The compressive strength (CS) values of the K0–K4 SCLWC mixtures at 7 and 28 days reveal notable trends. Using 10% FA in K1 decreased the CS at both 7 days (12.16 MPa) and 28 days (22.36 MPa), attributed to FA’s gradual pozzolanic activity. Conversely, K2 with SF showed increased CS at 7 days (17.88 MPa) and 28 days (29.89 MPa) due to SF’s rapid pozzolanic activity. Incorporating EPA into K3 and K4 reduced the CS values compared to PA, indicating EPA’s lower strength contribution due to its porous structure.
Novel Collagen Membrane Formulations with Irinotecan or Minocycline for Potential Application in Brain Cancer
Authors: Idu Andreea-Anamaria , Albu Kaya Mădălina Georgiana , Rău Ileana , Radu Nicoleta , Dinu-Pîrvu Cristina-Elena , Ghica Mihaela Violeta
Published: July 2024

Our study explores the development of collagen membranes with integrated minocycline or irinotecan, targeting applications in tissue engineering and drug delivery systems. Type I collagen, extracted from bovine skin using advanced fibril-forming technology, was crosslinked with glutaraldehyde to create membranes. These membranes incorporated minocycline, an antibiotic, or irinotecan, a chemotherapeutic agent, in various concentrations. The membranes, varying in drug concentration, were studied by water absorption and enzymatic degradation tests, demonstrating a degree of permeability. We emphasize the advantages of local drug delivery for treating high-grade gliomas, highlighting the targeted approach’s efficacy in reducing systemic adverse effects and enhancing drug bioavailability at the tumor site. The utilization of collagen membranes is proposed as a viable method for local drug delivery. Irinotecan’s mechanism, a topoisomerase I inhibitor, and minocycline’s broad antibacterial spectrum and inhibition of glial cell-induced membrane degradation are discussed. We critically examine the challenges posed by the systemic administration of chemotherapeutic agents, mainly due to the blood–brain barrier’s restrictive nature, advocating for local delivery methods as a more effective alternative for glioblastoma treatment. These local delivery strategies, including collagen membranes, are posited as significant advancements in enhancing therapeutic outcomes for glioblastoma patients.
The State of Health of Electrical Connectors
Authors: Song Jian , Shukla Abhay , Probst Roman
Published: July 2024

For modern machines, factories and electric and autonomous vehicles, the importance of vreliable electrical connectors cannot be overstated. With an increasing number of connectors being used in machines, factories and vehicles, ensuring their reliability is crucial for comfort and safety alike. One of the key indicators of reliability is the lifetime of connectors. To evaluate the lifetime of electrical connectors, a testing method and a model for calculating their lifetime based on the test data were developed. The results from these tests were compared to failure analysis data from long-term field operations. The findings indicate that the laboratory tests can accurately reproduce the main failures observed in the field. However, such lifetime tests can be time- and labor-intensive. To address this challenge, a data-driven method is proposed that predicts the lifetime of electrical connectors using statistical analysis of electrical contact resistance data collected from short-term tests. The predictions from this method were compared to actual results obtained from long-term tests. A strong correlation was observed between the contact resistance development in short-term tests and the number of failures in later stages of testing. Thus, apart from predicting the lifetime of connectors, this method can also be applied for failure prognosis in real-time operations.
Model-Based Adaptive Control of Bioreactors—A Brief Review
Authors: Lyubenova Velislava , Ignatova Maya , Zoteva Dafina , Roeva Olympia
Published: July 2024

This article summarizes the authors’ experiences in the development and application of the General Dynamical Model Approach related to adaptive linearizing control of biotechnological processes. Special attention has been given to some original, innovative solutions in model-based process control theory: new formalization of biotechnological process kinetics, derivation and tuning of the general software sensor of the full kinetics of biotechnological processes, and a general algorithm for fully adaptive linearizing control with software sensors. These theoretical solutions are the basis of three control strategies—fully adaptive control of the main substrate, partially adaptive control of intermediate metabolite, and recognition and stabilization of the desired physiological state based on the proposed theoretical solutions. Each strategy is illustrated in different case studies. The advantages and limitations of each of them are identified and discussed. The derived algorithms for monitoring and controlling the considered biotechnological processes are realized and included in a software platform named Interactive System for Education in Modelling and Control of Bioprocesses (InSEMCoBio). The InSEMCoBio modules and their main functions are discussed. The effectiveness of the proposed control strategies (achieving maximum productivity) has been proven through a series of simulation investigations of the considered case studies.
Algorithms for Densest Subgraphs of Vertex-Weighted Graphs
Authors: Liu Zhongling , Chen Wenbin , Li Fufang , Qi Ke , Wang Jianxiong
Published: July 2024

Finding the densest subgraph has tremendous potential in computer vision and social network research, among other domains. In computer vision, it can demonstrate essential structures, and in social network research, it aids in identifying closely associated communities. The densest subgraph problem is finding a subgraph with maximum mean density. However, most densest subgraph-finding algorithms are based on edge-weighted graphs, where edge weights can only represent a single value dimension, whereas practical applications involve multiple dimensions. To resolve the challenge, we propose two algorithms for resolving the densest subgraph problem in a vertex-weighted graph. First, we present an exact algorithm that builds upon Goldberg’s original algorithm. Through theoretical exploration and analysis, we rigorously verify our proposed algorithm’s correctness and confirm that it can efficiently run in polynomial time O(n(n + m)log2n) is its temporal complexity. Our approach can be applied to identify closely related subgroups demonstrating the maximum average density in real-life situations. Additionally, we consistently offer an approximation algorithm that guarantees an accurate approximation ratio of 2. In conclusion, our contributions enrich theoretical foundations for addressing the densest subgraph problem.
An Improved K-Means Algorithm Based on Contour Similarity
Authors: Zhao Jing , Bao Yanke , Li Dongsheng , Guan Xinguo
Published: July 2024

The traditional k-means algorithm is widely used in large-scale data clustering because of its easy implementation and efficient process, but it also suffers from the disadvantages of local optimality and poor robustness. In this study, a Csk-means algorithm based on contour similarity is proposed to overcome the drawbacks of the traditional k-means algorithm. For the traditional k-means algorithm, which results in local optimality due to the influence of outliers or noisy data and random selection of the initial clustering centers, the Csk-means algorithm overcomes both drawbacks by combining data lattice transformation and dissimilar interpolation. In particular, the Csk-means algorithm employs Fisher optimal partitioning of the similarity vectors between samples for the process of determining the number of clusters. To improve the robustness of the k-means algorithm to the shape of the clusters, the Csk-means algorithm utilizes contour similarity to compute the similarity between samples during the clustering process. Experimental results show that the Csk-means algorithm provides better clustering results than the traditional k-means algorithm and other comparative algorithms.
Improving the Accuracy of Permeability Data to Gain Predictive Power: Assessing Sources of Variability in Assays Using Cell Monolayers
Authors: Pires Cristiana L. , Moreno Maria João
Published: July 2024

The ability to predict the rate of permeation of new compounds across biological membranes is of high importance for their success as drugs, as it determines their efficacy, pharmacokinetics, and safety profile. In vitro permeability assays using Caco-2 monolayers are commonly employed to assess permeability across the intestinal epithelium, with an extensive number of apparent permeability coefficient (Papp) values available in the literature and a significant fraction collected in databases. The compilation of these Papp values for large datasets allows for the application of artificial intelligence tools for establishing quantitative structure–permeability relationships (QSPRs) to predict the permeability of new compounds from their structural properties. One of the main challenges that hinders the development of accurate predictions is the existence of multiple Papp values for the same compound, mostly caused by differences in the experimental protocols employed. This review addresses the magnitude of the variability within and between laboratories to interpret its impact on QSPR modelling, systematically and quantitatively assessing the most common sources of variability. This review emphasizes the importance of compiling consistent Papp data and suggests strategies that may be used to obtain such data, contributing to the establishment of robust QSPRs with enhanced predictive power.
A Comparative Analysis of a Microstructure and Properties for Monel K500 Hot-Rolled to a Round Bar and Wire Deposited on a Round Surface
Authors: Kostryzhev Andrii , Marenych Olexandra , Pan Zengxi , Li Huijun , Duin Stephen van
Published: July 2024

Metal manufacturing processes based on deformation (forging, rolling) result in a fine grain structure with a complex dislocation substructure, which positively influence mechanical properties. Casting and additive manufacturing (powder- or wire-based) usually produce a coarse grain structure with a poorly developed dislocation substructure, which negatively affect mechanical properties. Heat treatment may alter phase balance and stimulate precipitation strengthening; however, precipitation kinetics depends on the dislocation substructure. In this paper, a comparative study of the microstructure and strength is presented for Monel K500 alloy containing 63 Ni, 30 Cu, 2.0 Mn, and 2.0 Fe (wt.%), and microalloyed with Al, Ti, and C hot-rolled to a round bar and deposited on a round surface using wire additive manufacturing (WAAM) technology. An increased dislocation density and number density of fine precipitates resulted in 8–25% higher hardness and 1.8–2.6 times higher compression yield stress in the hot-rolled alloy compared to these in the WAAM-produced alloy. However, due to a high work hardening rate, only 3–10% cold deformation was necessary to increase the strength of the WAAM alloy to this of the hot-rolled one. Age hardening heat treatment, through the intensification of the precipitation strengthening mechanism, reduced the value of cold deformation strain required to equalise the properties. Based on the obtained results, a new technology consisting of additive manufacturing, heat treatment, and cold deformation can be proposed. It can produce WAAM components with strength and hardness improved to the level of hot-rolled components, which is a significant development of additive manufacturing.
A Low Mismatch Current Charge Pump Applied to Phase-Locked Loops
Authors: Guo Min , Wang Lixin , Wang Shixin , Lu Jiacheng , Cui Mengyao
Published: July 2024

This paper presents a charge pump circuit with a wide output range and low current mismatch applied to phase-locked loops. In this designed structure, T-shaped analog switches are adopted to suppress the non-ideal effects of clock feedthrough, switching time mismatch, and charge injection. A source follower and current splitting circuits are proposed to improve the matching accuracy of the charging and discharging currents and reduce the current mismatch rate. A rail-to-rail high-gain amplifier with a negative feedback connection is introduced to suppress the charge-sharing effect of the charge pump. A cascode current mirror with a high output impedance is used to provide the charge and discharge currents for the charge pump, which not only improves the current accuracy of the charge pump but also increases the output voltage range. The proposed charge pump is designed and simulated based on a 65 nm CMOS process. The results show that when the power supply voltage is 1.2 V, the output current of the charge pump is 100 μA, the output voltage is in the range of 0.2~1 V, and the maximum current mismatch rate and current variation rate are only 0.21% and 1.4%, respectively.
Characteristics of Nanoparticles in Late Pliocene Paleo-Mountain Fire Relics in Jinsuo Basin, Yunnan Province and Their Implications for Paleoclimate Evolution
Authors: Zhang Peng , Liu Bangjun , Wang Yaqin , Zuo Lei , Liu Rui , Wang Jialong , Wang Ru
Published: July 2024

Wildfires significantly affect climate and environmental changes, closely tied to extreme weather responses. Vegetation combustion emits greenhouse gases (CO2, CH4, CO), warming the climate. Climate shifts, in turn, impact vegetation growth, altering combustible material types and quantities, thus affecting wildfire intensity, duration, and frequency. Wildfires profoundly affect ecosystems, influenced by factors like atmospheric oxygen and climate. Their combustion gases impact climate and vegetation growth. Recent advancements in studying ancient wildfires include analyzing nanoparticles as key indicators. This study discovered six types of nanoparticles in ancient wildfire remains, with sizes ranging from 50 nm to 500 nm and diverse compositions including elements such as C, O, Mg, Al, Ti, Fe, S, Ca, and P. These findings indicate that wildfires generate a variety of nanoparticles, offering new insights into ancient fire events. Elemental analysis revealed low magnesium but high calcium and aluminum levels, suggesting a warm, humid paleoclimate during these fires. The presence of high Ti-O ratios and carbon-rich nanoparticles points to ground fires with incomplete combustion. This research underscores the significance of nanoparticles in understanding the history and characteristics of ancient wildfires.
Study of a Copper Oxide Leaching in Alkaline Monosodium Glutamate Solution
Authors: Perea Carlos G. , Ihle Christian , Dyer Laurence , Díaz Quezada Simón , Estay Humberto
Published: July 2024

Oxide copper minerals are commonly extracted via acidic leaching, using acids such as H2SO4, HCl, or HNO3. These strong acids are the most widely used because of their high dissolution kinetics. However, their main concern is the high acid consumption because copper oxide deposits contain large amounts of acid-consuming gangue. This paper proposes using an alternative aqueous alkaline monosodium glutamate (MSG) system to leach copper oxide minerals. Tenorite (CuO) was used as the copper oxide mineral under study. The influence of process variables (such as temperature and glutamate concentration) and kinetics of this system on copper leaching from tenorite were studied. The results showed that temperature has a significant effect on copper dissolution rates. Increased temperature from 15 °C to 60 °C enhanced the copper extraction from 9.1% to 97.7% after 2 h. Leaching kinetics were analyzed using the shrinking core model (SCM) under various conditions, indicating that the leaching rate presented a mixed control. This method, however, fails to describe leaching for broad particle sizes due to its requirement for single-sized solid grains. This study demonstrated that a large particle size distribution in tenorite supported a successful extension of the SCM for leaching it from mixed glutamate solutions. The activation energy for the 15–60 °C temperature range was calculated to be 102.6 kJ/mol for the chemical control.
Odours in Asphalt: Analysis of the Release of H2S from Bitumen by a Mass Spectrometric Residual Gas Analyser
Authors: Monteleone Marcello , Di Luca Giuseppe , Filomia Marcello , Fuoco Alessio , Figoli Alberto , Jansen Johannes Carolus
Published: July 2024

During the production and laying phases of hot-mixing asphalt (HMA), various volatile organic compounds (VOCs) and noxious gases such as H2S are released into the atmosphere. These emissions are a serious environmental problem, a risk to human health, and expose workers and residents to unfriendly odours. The aim of this study was the development of a fast and sensitive analytical method to detect the H2S emitted from hot bituminous binder that is generally used in the various stages of asphalt production, processing, handling and during road construction. The method consisted in the analysis of evolved H2S from a flask with molten bitumen, using nitrogen as a carrier gas to lead the volatile compounds into a residual gas analyser equipped with a quadrupole mass spectrometer. The analysis was performed following the H2S-specific signals at m/z 33 (HS+) and at m/z 34 (H2S+) in real time, directly on the sample without laborious and expensive pre-treatments and with short response times (<6 s). Calibration with a standard mixture of 1000 ppm of H2S in nitrogen allows semi-quantitative H2S detection. The sensitivity and rapidity of the method were evaluated by quenching the release of sulphur compounds with commercial odour-suppressing agents. Upon addition of 0.1% of additive in two minutes, the H2S signal drops about 80% in two minutes, confirming the good response of the method, even with a very complex matrix.
Current and Future Perspectives of Bioactive Glasses as Injectable Material
Authors: Mîrț Andreea-Luiza , Ficai Denisa , Oprea Ovidiu-Cristian , Vasilievici Gabriel , Ficai Anton
Published: July 2024

This review covers recent compositions of bioactive glass, with a specific emphasis on both inorganic and organic materials commonly utilized as matrices for injectable materials. The major objective is to highlight the predominant bioactive glass formulations and their clinical applications in the biomedical field. Previous studies have highlighted the growing interest among researchers in bioactive glasses, acknowledging their potential to yield promising outcomes in this field. As a result of this increased interest, investigations into bioactive glass have prompted the creation of composite materials and, notably, the development of injectable composites as a minimally invasive method for administering the material within the human body. Injectable materials have emerged as a promising avenue to mitigate various challenges. They offer several advantages, including minimizing invasive surgical procedures, reducing patient discomfort, lowering the risk of postoperative infection and decreasing treatment expenses. Additionally, injectable materials facilitate uniform distribution, allowing for the filling of defects of any shape.
Differential Expression of lncRNAs in HIV Patients with TB and HIV-TB with Anti-Retroviral Treatment
Authors: Reid Victoria A. , Ramos Enrique I. , Veerapandian Raja , Carmona Areanna , Gadad Shrikanth S. , Dhandayuthapani Subramanian
Published: July 2024

Tuberculosis (TB) is the leading cause of death among people with HIV-1 infection. To improve the diagnosis and treatment of HIV-TB patients, it is important to understand the mechanisms underlying these conditions. Here, we used an integrated genomics approach to analyze and determine the lncRNAs that are dysregulated in HIV-TB patients and HIV-TB patients undergoing anti-retroviral therapy (ART) using a dataset available in the public domain. The analyses focused on the portion of the genome transcribed into non-coding transcripts, which historically have been poorly studied and received less focus. This revealed that Mtb infection in HIV prominently up-regulates the expression of long non-coding RNA (lncRNA) genes DAAM2-AS1, COL4A2-AS1, LINC00599, AC008592.1, and CLRN1-AS1 and down-regulates the expression of lncRNAs AC111000.4, AC100803.3, AC016168.2, AC245100.7, and LINC02073. It also revealed that ART down-regulates the expression of some lncRNA genes (COL4A2-AS1, AC079210.1, MFA-AS1, and LINC01993) that are highly up-regulated in HIV-TB patients. Furthermore, the interrogation of the genomic regions that are associated with regulated lncRNAs showed enrichment for biological processes linked to immune pathways in TB-infected conditions. However, intriguingly, TB patients treated with ART showed completely opposite and non-overlapping pathways. Our findings suggest that lncRNAs could be used to identify critical diagnostic, prognostic, and treatment targets for HIV-TB patients.
Protective Effects of Velvet Antler Methanol Extracts on Hypoxia-Induced Damage in Caenorhabditis elegans through HIF-1 and ECH-8 Mediated Lipid Accumulation
Authors: Li Ru , Li Hongyuan , Wang Xiaohui , Peng Yinghua
Published: July 2024

Velvet antler, a traditional tonic widely used in East Asia for its health benefits, is explored in this study for its protective effects against hypoxia-induced damage using Caenorhabditis elegans (C. elegans) as a model. Hypoxia, characterized by low oxygen availability, induces significant physiological stress and potential tissue damage. Our research demonstrates that methanol extracts from velvet antler (MEs) enhance the survival of C. elegans under hypoxic conditions. This enhancement is achieved through the stabilization of hypoxia-inducible factor-1 (HIF-1) and the promotion of lipid accumulation, both of which are crucial for mitigating cellular damage. Specifically, MEs improve mitochondrial function, increase ATP production, and aid in the recovery of physical activity in C. elegans post-hypoxia or following hypoxia–reoxygenation (HR). The pivotal role of HIF-1 is underscored by the loss of these protective effects when HIF-1 function is inhibited. Additionally, our findings reveal that the gene related to lipid metabolism, ech-8, significantly contributes to the lipid accumulation that enhances resilience to hypoxia in C. elegans treated with MEs. These results not only highlight the therapeutic potential of velvet antler in modern medical applications, particularly for conditions involving hypoxic stress, but also provide insights into the molecular mechanisms by which MEs confer protection against hypoxic damage.
Hemoglobin Regeneration Efficiency and Relative Iron Bioavailability of Four Elemental Iron Powders in Rats
Authors: Swain James H. , Nemeth Ryan C. , Bethi Anshul R. , Jang Caroline J. , Zheng Eva L.
Published: July 2024

Effective food fortification strategies using elemental iron powders (EIPs) are needed to combat iron deficiency anemia. The purpose of this study was to determine hemoglobin regeneration efficiency (HRE) and relative iron bioavailability (RBV) of four food-grade EIPs (El-Lyte (EL), Hi-Sol (HS), H-325 (H3), and A-131 (A1)) by treating anemic rats with 14 d iron repletion diets (uncooked and cooked), fortified with a 12, 24, or 36 mg iron/kg diet of the EIPs, ferrous sulfate monohydrate (FS, FeSO4•H2O), or no added iron (control), n = 9–12/group. The ability of EL and HS to maintain hemoglobin for 6 weeks on the 6 mg iron/kg diet was also studied. The dissolution rate of iron from the EIPs was measured in hydrochloric acid at pH 1.0. Compared to FS, the EL, HS, and A1 EIPs had >50% overall RBV, with the following order: HS > A1 > EL > H3 (p ≤ 0.05); the effect of cooking was not significant (p > 0.05). Dissolution testing revealed that the mean RBV of the EIPs was positively associated with the percentage of iron solubility. In the 6-week maintenance study, EL and HS maintained hemoglobin as well as FS. Overall, the findings show that at the concentrations of iron tested, these EIPs are effective fortification agents to replenish hemoglobin and correct iron deficiency anemia.
Effect of Urolithin A on the Improvement of Circadian Rhythm Dysregulation in Intestinal Barrier Induced by Inflammation
Authors: Du Yao , Chen Xinyue , Kajiwara Susumu , Orihara Kanami
Published: July 2024

Circadian rhythm plays an important role in intestinal homeostasis and intestinal immune function. Circadian rhythm dysregulation was reported to induce intestinal microbiota dysbiosis, intestinal barrier disruption, and trigger intestinal inflammation. However, the relationship between intestinal microbiota metabolites and the circadian rhythm of the intestinal barrier was still unclear. Urolithin A (UA), a kind of intestinal microbial metabolite, was selected in this study. Results showed UA influenced on the expression rhythm of the clock genes BMAL1 and PER2 in intestinal epithelial cells. Furthermore, the study investigated the effects of UA on the expression rhythms of clock genes (BMAL1 and PER2) and tight junctions (OCLN, TJP1, and CLND1), all of which were dysregulated by inflammation. In addition, UA pre-treatment by oral administration to female C57BL/6 mice showed the improvement in the fecal IgA concentrations, tight junction expression (Clnd1 and Clnd4), and clock gene expression (Bmal1 and Per2) in a DSS-induced colitis model induced using DSS treatment. Finally, the Nrf2-SIRT1 signaling pathway was confirmed to be involved in UA’s effect on the circadian rhythm of intestinal epithelial cells by antagonist treatment. This study also showed evidence that UA feeding showed an impact on the central clock, which are circadian rhythms in SCN. Therefore, this study highlighted the potential of UA in treating diseases like IBD with sleeping disorders by improving the dysregulated circadian rhythms in both the intestinal barrier and the SCN.
An Evaluation of Healthy Hydration Recommendations for 93 Countries with Sugary Beverage Tax Legislation Globally, 2000–2023
Authors: Leary Nicole , Parker Molly K. , Rincón Gallardo Patiño Sofía , Kraak Vivica I.
Published: July 2024

Adequate water intake is essential for human health. Sugary beverage taxes are a best buy policy to reduce obesity and diet-related non-communicable diseases. Food-based dietary guidelines (FBDGs) promote healthy dietary patterns. The study purpose was to evaluate national FBDGs for countries with sugary beverage tax legislation (2000–2023) to promote water and discourage sugary beverage consumption. We developed a coding framework to conduct a content analysis of FBDG documents, and used six indicators to identify messages and images to assign healthy hydration recommendation (HHR) scores from 0–12 to compare FBDGs across countries and six regions. Results showed 93 countries with sugary beverage tax legislation of which 58 countries (62%) had published FBDGs (1998–2023). Of 58 FBDGs reviewed, 48 (83%) had complementary recommendations that encouraged water and discouraged sugary beverages. Of 93 countries, 13 (14%) had the highest HHR scores (11–12); 22, (24%) had high HHR scores (9–10); 20 (21%) had medium HHR scores (4–8); 3 (3%) had low HHR scores (0–3); and 35 (38%) countries had no FBDGs. To reduce health risks for populations, governments must ensure policy coherence to optimize sugary beverage tax impacts by developing FBDGs that encourage water and discourage sugary beverages complementary to national policies.