bluuebunny/crossref_metadata_2025 huggingface dataset:
Time Spent Jogging/Running and Biological Aging in 4458 U.S. Adults: An NHANES Investigation
Authors: Blackmon Christina M. , Tucker Larry A. , Bailey Bruce W. , Davidson Lance E.
Published: October 2023

Telomere length is a good index of cellular aging. Longer telomeres are predictive of longer life, and healthy lifestyles are associated with longer telomeres. This study explored the relationship between time spent jogging or running each week and leukocyte telomere length (LTL) in 4458 randomly selected U.S. adults. The association was studied using data collected by the National Health and Nutrition Examination Survey (NHANES), and a cross-sectional design. Total weekly jog/run time was calculated from survey responses. From the minute totals, three categories were formed: <10 min/week, 10–74 min/week, and ≥75 min/week. Adults in the third category met the U.S. guidelines. Data were analyzed using one-way ANOVA. Partial correlation was used to adjust for differences in potential mediating factors, including demographic and lifestyle/medical factors. In the total sample, after adjusting for all the potential covariates, mean LTL significantly differed across the three jog/run categories (F = 4.1, p = 0.0272). Specifically, adults who met the guidelines via jogging and/or running had significantly longer telomeres than adults who performed no jogging/running. Adults in the middle category did not differ from the other two categories. A minimum of 75 min of jogging/running weekly is predictive of longer telomeres when compared to adults who do not jog or run regularly.
A Focus on Aging, HIV/AIDS, and Neurocognitive Challenges: Examining Southern Nevada HIV Sector Providers’ Awareness and Prospective Roles
Authors: Ranuschio Brandon , Bell Sherry , Flatt Jason D. , Barnes Lianne , Puno Trinity , Ribeiro Alexander , Sheik-Yosef Nadia , Villalobos Esmeralda , Wackens Janelle , Liboro Renato M.
Published: October 2023

Although abundant research has been carried out to investigate the underlying mechanisms that may cause neurocognitive challenges among middle-aged and older people living with HIV/AIDS (PLWH), to monitor the prevalence rates of HIV-related neurocognitive deficits, and to identify factors related to the improvement of diagnostic screening tools, classification and nosology, and clinical and rehabilitative treatment of HIV-Associated Neurocognitive Disorder (HAND); to date, there have been only a few studies that have explored and examined the awareness and work experiences HIV sector healthcare and service providers have related to HAND. To address this research gap, we conducted a qualitative, community-based participatory research study and interviewed 12 HIV sector providers in Southern Nevada, USA, from January to April 2022. After performing a thematic analysis of our interviews, we were able to identify two major themes and several sub-themes. Under our first major theme, provider awareness and knowledge, we identified four sub-themes: (1) prior knowledge and current awareness; (2) lived experiences of patients and clients with neurocognitive challenges; (3) lack of knowledge as a barrier to providing needed care; and (4) continuing education and professional development. Under our second major theme, prospective provider roles, we identified three sub-themes: (1) early detection; (2) direct and practical support; and (3) appropriate and timely referrals. In this article, we discuss our findings and lessons learned from our study, as well as their implications for the future work of researchers and providers in the HIV sector related to improving care and support for people aging with HIV/AIDS and experiencing neurocognitive challenges.
Batch Simplification Algorithm for Trajectories over Road Networks
Authors: Reyes Gary , Estrada Vivian , Tolozano-Benites Roberto , Maquilón Victor
Published: October 2023

The steady increase in data generation by GPS systems poses storage challenges. Previous studies show the need to address trajectory compression. The demand for accuracy and the magnitude of data require effective compression strategies to reduce storage. It is posited that the combination of TD-TR simplification, Kalman noise reduction, and analysis of road network information will improve the compression ratio and margin of error. The GR algorithm is developed, integrating noise reduction and path compression techniques. Experiments are applied with trajectory data sets collected in the cities of California and Beijing. The GR algorithm outperforms similar algorithms in compression ratio and margin of error, improving storage efficiency by up to 89.090%. The combination of proposed techniques presents an efficient solution for GPS trajectory compression, allowing to improve storage in trajectory analysis applications.
The Determination of Mitochondrial Mass Is a Prerequisite for Accurate Assessment of Peripheral Blood Mononuclear Cells’ Oxidative Metabolism
Authors: Tessema Belay , Haag Janine , Sack Ulrich , König Brigitte
Published: October 2023

Mitochondria are responsible for ATP synthesis through oxidative phosphorylation in cells. However, there are limited data on the influence of mitochondrial mass (MM) in the adequate assessment of cellular stress assay (CSA) results in human peripheral blood mononuclear cells (PBMCs). Therefore, the aim of this study was to determine MM in PBMCS and assess its influence on the results of CSA measurements. Blood samples were collected and sent to the laboratory for MM and CSA measurements during different seasons of the year. The mitochondrial mass was determined based on the mtDNA:nDNA ratio in PBMCs using quantitative real-time PCR (qRT-PCR). CSA was measured using Seahorse technology. The MM was significantly lower during summer and autumn compared to winter and spring (p < 0.0001). On the contrary, we found that the maximal respiration per mitochondrion (MP) was significantly higher in summer and autumn compared to winter and spring (p < 0.0001). The estimated effect of MM on mitochondrial performance was −0.002 pmol/min/mitochondrion (p < 0.0001) and a correlation coefficient (r) of −0.612. Similarly, MM was negatively correlated with maximal respiration (r = −0.12) and spare capacity (in % r = −0.05, in pmol/min r = −0.11). In conclusion, this study reveals that MM changes significantly with seasons and is negatively correlated with CSA parameters and MP. Our findings indicate that the mitochondrial mass is a key parameter for determination of mitochondrial fitness. Therefore, we recommend the determination of MM during the measurement of CSA parameters for the correct interpretation and assessment of mitochondrial function.
Pharmacokinetic Model-Based Control across the Blood–Brain Barrier for Circadian Entrainment
Authors: Murdoch Síofra Ó. , Aiello Eleonora M. , Doyle Francis J.
Published: October 2023

The ability to shift circadian phase in vivo has the potential to offer substantial health benefits. However, the blood–brain barrier prevents the absorption of the majority of large and many small molecules, posing a challenge to neurological pharmaceutical development. Motivated by the presence of the circadian molecule KL001, which is capable of causing phase shifts in a circadian oscillator, we investigated the pharmacokinetics of different neurological pharmaceuticals on the dynamics of circadian phase. Specifically, we developed and validated five different transport models that describe drug concentration profiles of a circadian pharmaceutical at the brain level under oral administration and designed a nonlinear model predictive control (MPC)-based framework for phase resetting. Performance of the novel control algorithm based on the identified pharmacokinetic models was demonstrated through simulations of real-world misalignment scenarios due to jet lag. The time to achieve a complete phase reset for 11-h phase delay ranged between 48 and 72 h, while a 5-h phase advance was compensated in 30 to 60 h. This approach provides mechanistic insight into the underlying structure of the circadian oscillatory system and thus leads to a better understanding of the feasibility of therapeutic manipulations of the system.
Transcriptional Signatures and Network-Based Approaches Identified Master Regulators Transcription Factors Involved in Experimental Periodontitis Pathogenesis
Authors: Vicencio Emiliano , Nuñez-Belmar Josefa , Cardenas Juan P. , Cortés Bastian I. , Martin Alberto J. M. , Maracaja-Coutinho Vinicius , Rojas Adolfo , Cafferata Emilio A. , González-Osuna Luis , Vernal Rolando , Cortez Cristian
Published: October 2023

Periodontitis is a chronic inflammatory disease characterized by the progressive and irreversible destruction of the periodontium. Its aetiopathogenesis lies in the constant challenge of the dysbiotic biofilm, which triggers a deregulated immune response responsible for the disease phenotype. Although the molecular mechanisms underlying periodontitis have been extensively studied, the regulatory mechanisms at the transcriptional level remain unclear. To generate transcriptomic data, we performed RNA shotgun sequencing of the oral mucosa of periodontitis-affected mice. Since genes are not expressed in isolation during pathological processes, we disclose here the complete repertoire of differentially expressed genes (DEG) and co-expressed modules to build Gene Regulatory Networks (GRNs) and identify the Master Transcriptional Regulators of periodontitis. The transcriptional changes revealed 366 protein-coding genes and 42 non-coding genes differentially expressed and enriched in the immune response. Furthermore, we found 13 co-expression modules with different representation degrees and gene expression levels. Our GRN comprises genes from 12 gene clusters, 166 nodes, of which 33 encode Transcription Factors, and 201 connections. Finally, using these strategies, 26 master regulators of periodontitis were identified. In conclusion, combining the transcriptomic analyses with the regulatory network construction represents a powerful and efficient strategy for identifying potential periodontitis-therapeutic targets.
The Mechanism of Interleukin 33-Induced Stimulation of Interleukin 6 in MLO-Y4 Cells
Authors: Noguchi Sae , Yamasaki Ryota , Nagai-Yoshioka Yoshie , Sato Tsuyoshi , Kuroishi Kayoko , Gunjigake Kaori , Ariyoshi Wataru , Kawamoto Tatsuo
Published: October 2023

The differentiation and function of osteocytes are controlled by surrounding cells and mechanical stress; however, the detailed mechanisms are unknown. Recent findings suggest that IL-33 is highly expressed in periodontal tissues in orthodontic tooth movement. The present study aimed to elucidate the effect of IL-33 on the expression of regulatory factors for bone remodeling and their molecular mechanisms in the osteocyte-like cell line MLO-Y4. MLO-Y4 cells were treated with IL-33, and the activation of intracellular signaling molecules and transcriptional factors was determined using Western blot analysis and chromatin immunoprecipitation assay. IL-33 treatment enhanced the expression of IL-6 in MLO-Y4 cells, which was suppressed by the knockdown of the IL-33 receptor ST2L. Additionally, IL-33 treatment induced activation of NF-κB, JNK/AP-1, and p38 MAPK signaling pathways in MLO-Y4 cells. Moreover, pretreatment with specific inhibitors of NF-κB, p38 MAPK, and JNK/AP-1 attenuated the IL-33-induced expression of IL-6. Furthermore, chromatin immunoprecipitation indicated that IL-33 increased c-Jun recruitment to the IL-6 promoter. Overall, these results suggest that IL-33 induces IL-6 expression and regulates osteocyte function via activation of the NF-κB, JNK/AP-1, and p38 MAPK pathways through interaction with ST2L receptors on the plasma membrane.
Antiviral Efficacy of RNase H-Dependent Gapmer Antisense Oligonucleotides against Japanese Encephalitis Virus
Authors: Okamoto Shunsuke , Echigoya Yusuke , Tago Ayaka , Segawa Takao , Sato Yukita , Itou Takuya
Published: October 2023

RNase H-dependent gapmer antisense oligonucleotides (ASOs) are a promising therapeutic approach via sequence-specific binding to and degrading target RNAs. However, the efficacy and mechanism of antiviral gapmer ASOs have remained unclear. Here, we investigated the inhibitory effects of gapmer ASOs containing locked nucleic acids (LNA gapmers) on proliferating a mosquito-borne flavivirus, Japanese encephalitis virus (JEV), with high mortality. We designed several LNA gapmers targeting the 3′ untranslated region of JEV genomic RNAs. In vitro screening by plaque assay using Vero cells revealed that LNA gapmers targeting a stem-loop region effectively inhibit JEV proliferation. Cell-based and RNA cleavage assays using mismatched LNA gapmers exhibited an underlying mechanism where the inhibition of viral production results from JEV RNA degradation by LNA gapmers in a sequence- and modification-dependent manner. Encouragingly, LNA gapmers potently inhibited the proliferation of five JEV strains of predominant genotypes I and III in human neuroblastoma cells without apparent cytotoxicity. Database searching showed a low possibility of off-target binding of our LNA gapmers to human RNAs. The target viral RNA sequence conservation observed here highlighted their broad-spectrum antiviral potential against different JEV genotypes/strains. This work will facilitate the development of an antiviral LNA gapmer therapy for JEV and other flavivirus infections.
User Authentication Mechanisms Based on Immersive Technologies: A Systematic Review
Authors: Anastasaki Ioanna , Drosatos George , Pavlidis George , Rantos Konstantinos
Published: October 2023

Immersive technologies are revolutionary technological advancements that offer users unparalleled experiences of immersion in a virtual or mixed world of virtual and real elements. In such technology, user privacy, security, and anonymity are paramount, as users often share private and sensitive information. Therefore, user authentication is a critical requirement in these environments. This paper presents a systematic literature review of recently published research papers on immersive technology-based user authentication mechanisms. After conducting the literature search in September 2023 using Scopus, the selection process identified 36 research publications that were further analyzed. The analysis revealed three major types of authentications related to immersive technologies, consistent with previous works: knowledge-based, biometric, and multi-factor methods. The reviewed papers are categorized according to these groups, and the methods used are scrutinized. To the best of our knowledge, this systematic literature review is the first that provides a comprehensive consolidation of immersive technologies for user authentication in virtual, augmented, and mixed reality.
Photon-Counting CT Material Decomposition in Bone Imaging
Authors: Bhattarai Abhisek , Tanaka Ray , Yeung Andy Wai Kan , Vardhanabhuti Varut
Published: October 2023

The accurate screening of osteoporosis is important for identifying persons at risk. The diagnosis of bone conditions using dual X-ray absorptiometry is limited to extracting areal bone mineral density (BMD) and fails to provide any structural information. Computed tomography (CT) is excellent for morphological imaging but not ideal for material quantification. Advanced photon-counting detector CT (PCD-CT) possesses high spectral sensitivity and material decomposition capabilities to simultaneously determine qualitative and quantitative information. In this study, we explored the diagnostic utility of PCD-CT to provide high-resolution 3-D imaging of bone microarchitecture and composition for the sensitive diagnosis of bone in untreated and ovariectomized rats. PCD-CT accurately decomposed the calcium content within hydroxyapatite phantoms (r = 0.99). MicroCT analysis of tibial bone revealed significant differences in the morphological parameters between the untreated and ovariectomized samples. However, differences in the structural parameters of the mandible between the treatment groups were not observed. BMD determined with microCT and calcium concentration decomposed using PCD-CT differed significantly between the treatment groups in both the tibia and mandible. Quantitative analysis with PCD-CT is sensitive in determining the distribution of calcium and water components in bone and may have utility in the screening and diagnosis of bone conditions such as osteoporosis.
Shale Gas Exploration and Development Potential Analysis of Lower Cambrian Niutitang Formation and Lower Silurian Longmaxi Formation in Northwestern Hunan, South China, Based on Organic Matter Pore Evolution Characteristics
Authors: Miao Yanan , Wang Pengfei , Li Xin , Huang Haiping , Jin Can , Gao Wei
Published: October 2023

Shale gas production is obviously higher within the Silurian Longmaxi Formation than that of the Cambrian Niutitang Formation according to the drilling test results in the northwest Hunan area. To clarify the reasons behind this variation, core samples from the two sets of shales were studied for a comprehensive comparison and analysis of their organic matter (OM) pore structure. Methods were used, including the total organic carbon content test, the vitrinite reflectance test, X-ray diffraction, and focused ion-beam scanning electron microscopy (FIB-SEM). The results show that these two shales have similar reservoir characteristics, both with abundant organic matter and high content of brittle minerals. However, the Longmaxi shale with 2.3% to 3.0%Ro presents lower thermal maturity than the Niutitang shale with over 3.0%Ro. In the case of pore structure associated with OM, a huge difference exists between the two shales. The OM pore shape of the Longmaxi shale is very regular, being mostly round and oval, while the OM pore shape of the Niutitang shale is irregular, being flat with a thin middle and thick and elongated ends. An important factor affecting OM pore evolution is thermal maturity. In turn, the thermal maturity is controlled by the tectonic evolution process, especially the maximum paleo-burial depth. In conclusion, the paleo-burial depth of the Lower Cambrian Niutitang shale in northwest Hunan is too large, which leads to the excessive evolution of organic matter in the shale, and the physical and chemical properties are similar to graphite, which leads to the disappearance of OM pores. Shale gas has no effective reservoir space and is largely dispersed in geological history. At the same time, due to the insufficient hydrocarbon-generation evolution time of the Lower Silurian Longmaxi Formation shale in this area, the shale could not form enough gaseous hydrocarbons and a large amount of effective reservoir space (OM pores with regular shape and large pore size), and finally failed to become a gas reservoir. Therefore, the exploration and development potential of the marine shale gas of the Lower Cambrian Niutitang Formation and the Lower Silurian Longmaxi Formation in northwest Hunan is poor.
Emotional Profiles of Facebook Pages: Audience Response to Political News in Hong Kong
Authors: Nip Joyce Y. M. , Berthelier Benoit
Published: October 2023

As social media becomes a major channel of news access, emotions have emerged as a significant factor of news distribution. However, the influence of cultural differences on the relationship between emotions and news sharing remains understudied. This paper investigates the impact of cultural disparities on emotional responses to political news in Hong Kong. We introduce the notion of “emotional profile” to capture cultural differences in the level and structure of audiences’ emotional responses to political topics on Facebook news pages. The study was conducted at a highly significant political moment in the former British colony when the National Security Law (NSL) was passed. The study found that readers of China-critical news pages on Facebook express the highest emotional intensity while readers of China’s media in Hong Kong express the lowest emotional intensity, and readers of China-supporting media fall in between. Readers of China-critical Facebook news pages express the most anger, but their political news sharing is correlated the most with “wow” and “sad” reactions. In contrast, readers of Facebook pages of China’s media in Hong Kong are more likely to react with “love”, which is also the emotion most associated with their political news sharing. The notion of “emotional profile” helps discover similarities within and differences across political boundaries of the news ecosystem. We interpret the results with the help of recent scholarly understanding of emotional expression on social media within Hong Kong’s political context.
Microbial Exudates as Biostimulants: Role in Plant Growth Promotion and Stress Mitigation
Authors: Ansari Mariya , Devi B. Megala , Sarkar Ankita , Chattopadhyay Anirudha , Satnami Lovkush , Balu Pooraniammal , Choudhary Manoj , Shahid Muhammad Adnan , Jailani A. Abdul Kader
Published: October 2023

Microbes hold immense potential, based on the fact that they are widely acknowledged for their role in mitigating the detrimental impacts of chemical fertilizers and pesticides, which were extensively employed during the Green Revolution era. The consequence of this extensive use has been the degradation of agricultural land, soil health and fertility deterioration, and a decline in crop quality. Despite the existence of environmentally friendly and sustainable alternatives, microbial bioinoculants encounter numerous challenges in real-world agricultural settings. These challenges include harsh environmental conditions like unfavorable soil pH, temperature extremes, and nutrient imbalances, as well as stiff competition with native microbial species and host plant specificity. Moreover, obstacles spanning from large-scale production to commercialization persist. Therefore, substantial efforts are underway to identify superior solutions that can foster a sustainable and eco-conscious agricultural system. In this context, attention has shifted towards the utilization of cell-free microbial exudates as opposed to traditional microbial inoculants. Microbial exudates refer to the diverse array of cellular metabolites secreted by microbial cells. These metabolites enclose a wide range of chemical compounds, including sugars, organic acids, amino acids, peptides, siderophores, volatiles, and more. The composition and function of these compounds in exudates can vary considerably, depending on the specific microbial strains and prevailing environmental conditions. Remarkably, they possess the capability to modulate and influence various plant physiological processes, thereby inducing tolerance to both biotic and abiotic stresses. Furthermore, these exudates facilitate plant growth and aid in the remediation of environmental pollutants such as chemicals and heavy metals in agroecosystems. Much like live microbes, when applied, these exudates actively participate in the phyllosphere and rhizosphere, engaging in continuous interactions with plants and plant-associated microbes. Consequently, they play a pivotal role in reshaping the microbiome. The biostimulant properties exhibited by these exudates position them as promising biological components for fostering cleaner and more sustainable agricultural systems.
Network Activity and Ethereum Gas Prices
Authors: Koutmos Dimitrios
Published: October 2023

This article explores the extent to which network activity can explain changes in Ethereum transaction fees. Such fees are referred to as “gas prices” within the Ethereum blockchain, and are important inputs not only for executing transactions, but also for the deployment of smart contracts within the network. Using a bootstrapped quantile regression model, it can be shown that network activity, such as the sizes of blocks or the number of transactions and contracts, can have a heterogeneous relationship with gas prices across periods of low and high gas price changes. Of all the network activity variables examined herein, the number of intraday transactions within Ethereum’s blockchain is most consistent in explaining gas fees across the full distribution of gas fee changes. From a statistical perspective, the bootstrapped quantile regression approach demonstrates that linear modeling techniques may yield but a partial view of the rich dynamics found in the full range of gas price changes’ conditional distribution. This is an important finding given that Ethereum’s blockchain has undergone fundamental economic and technological regime changes, such as the recent implementation of the Ethereum Improvement Proposal (EIP) 1559, which aims to provide an algorithmic updating rule to estimate Ethereum’s “base fee”.
Abraham Model Descriptors for Vitamin K4: Prediction of Solution, Biological and Thermodynamic Properties
Authors: Motati Saikiran , Motati Ramya , Kandi Trisha , Acree William E.
Published: October 2023

Spectrophotometric measurements were used to determine the mole fraction solubilities of vitamin K4 dissolved in cyclohexane, methylcyclohexane, 1-heptanol, 2-butanol, 2-pentanol, 2-methyl-1-butanol, 4-methyl-2-pentanol, and cyclopentanol at 298.15 K. Results from our experimental measurements, combined with the published solubility data, are used to calculate the solute descriptors of the vitamin K4 solute. The calculated solute descriptors describe the observed solubility data to within an overall standard deviation of 0.110 log units. The calculated solute descriptors were also used to estimate the several blood-to-rat tissue partition coefficients of vitamin K4, as well as the equilibrium vapor pressure above the solid vitamin at 298 K, and the vitamin’s enthalpy of solvation in both water and in 1,4-dioxane organic mono-solvent.
Interactivity and Influence: A Research on the Relationship between Epitaph (muzhi 墓志) and Mourning Poetry for Deceased Wives in Ancient China
Authors: Yang Qiong
Published: October 2023

Epitaph and poetry are two different literary genres in ancient China. However, when they collectively address the theme of “mourning the deceased”, they demonstrate an evident phenomenon of permeation and interaction. Pan Yue, as the pioneer of mourning poetry, his personal expressions as well as the scenes and objects in his mourning poems have become fixed imageries of mourning, which have been applied to the epitaphs written by later literati for their deceased wives, enhancing the mourning attributes of these inscriptions. Some renowned poets such as Wei Yingwu 韦应物 (737–791) from the Tang 唐 Dynasty (618–907), and Li Mengyang 李梦阳 (1473–1530), from the Ming 明 Dynasty (1368–1644) would personally write tomb inscriptions while creating mourning poems for their deceased wives. Reading these two kinds of texts from the same author side by side not only deepens our understanding of both types of text, but also helps to examine the intertextual interactions between these two literary forms.
Effects of Contamination on Selected Rheological and Tribological Properties of Lubricating Greases Working in Underground Mines
Authors: Paszkowski Maciej , Stelmaszek Piotr Aleksander , Krzak Justyna
Published: October 2023

This study examines the effect of mining pollutants and wear products on the rheological and tribological properties of a lubricating grease working in the microclimate of the Polkowice-Sieroszowice mine belonging to the KGHM Polska Miedź Group (Polkowice, Poland). The material under investigation is a commercial lubricating grease thickened with complex lithium soap, based on mineral oil with a molybdenum disulfide (MoS2) addition. A sample of the grease was taken from one of the friction junctions of a self-propelled drilling jumbo operated in the mine. Comparative tests of the fresh grease and the spent grease were carried out. For the two greases, rheological tests, i.e., dynamic oscillation tests and tests in steady flow conditions, were carried out at a constant shear rate. The rheological tests were conducted using a rotational rheometer. Moreover, the tribological characteristics of the tested greases under different friction junction loads were carried out using a ball-on-disc tribometer. Besides friction resistance, the lubrication ability of the two greases was also evaluated through an analysis of the wear of the steel disks after the friction process. Contour and topographic maps of the wear traces of the discs together with their wear profiles were compared.
Control of Fluoride Pollution in Cemented Phosphogypsum Backfill by Citric Acid Pretreatment
Authors: Zhou Yanan , Shi Ying , Zhu Quanqi
Published: October 2023

Using phosphogypsum (PG) as the aggregate of cemented backfill is an economical and effective method of PG utilization. However, the stability and performance of cemented backfill are challenged by the rich fluoride content in PG. In this study, the effects of citric acid pretreatment on PG defluorination, backfill performance and environmental behavior were investigated by washing PG with different concentrations of citric acid and washing times. The results showed that the citric acid pretreatment could significantly reduce the fluoride content in PG and promote the hydration reaction with the binder, thus greatly reducing the usage and cost of the binder in actual production. Considering the efficiency of defluorination, the optimal citric acid concentration and washing times were determined to be 4% and 7–8 times, respectively. In addition, after citric acid pretreatment, the viscosity and setting time of the backfill slurry and the porosity of the backfill reduced, and the strength of the backfill improved, which was conducive to slurry pipeline transportation and underground mine stability. Finally, a further analysis of environmental behavior was conducted and it was found that the citric acid washing greatly reduced the content of fluoride in the bleeding water of slurry and the backfill leachate, which met the integrated wastewater discharge standard in China. The results of this study can provide important guidance for the large-scale recycling and environmental management of PG.
Powder Bed Thermal Diffusivity Using Laser Flash Three Layer Analysis
Authors: Habiba Ummay , Hebert Rainer J.
Published: October 2023

The thermal diffusivity of powder bed plays a crucial role in laser powder bed fusion (LPBF) additive manufacturing. The mechanical properties of the parts built by LPBF are immensely influenced by the thermal properties of the powder bed. This study aims to measure the thermal diffusivity of metallic powder, nickel-based super alloy Inconel718 (IN718), in LPBF using laser flash three-layered analysis in a DLF1600 instrument, which incorporates a special powder cell to encapsulate the powdered sample. Measurements were performed at different temperatures. The thermal diffusivity of several reference samples was measured for the purpose of validating the test results, and it was compared to published data for identical measures. It was observed that experimental results for powder samples were smaller than the actual thermal diffusivity of the sample. R software analysis was used to analyze test data in order to obtain powder thermal diffusivity values that were close to the actual values.
Investigating the Effect of Heat Treatment on the Microstructure and Hardness of Aluminum-Lithium Alloys
Authors: Radan Lida , Songmene Victor , Zedan Yasser , Samuel Fawzy H.
Published: October 2023

In this study, the effects of heat treatment on the microstructure and strength (micro-hardness) of an aluminum–lithium (Al-Li) base alloy containing copper (Cu) and scandium (Sc) were investigated, with a view to enhancing the alloy performance for aerospace applications. The heat treatment conditions were investigated to understand the precipitation behavior and the mechanisms involved in strengthening. Aging was carried out at temperatures of 130 °C and 150 °C for aging times of 1 h, 2.5 h, 5 h, 10 h, 15 h, 25 h, 35 h, and 45 h at each temperature for Al-Li alloy and at 160 °C, 180 °C, and 200 °C for aging times of 5 h, 10 h, 15 h, 20 h, 25 h, and 30 h at each temperature for Al-Li-Cu and Al-Li-Cu-Sc alloys. The investigation revealed that both solution heat treatment and artificial aging had a notable impact on strengthening the hardness of the alloy. This effect was attributed to the characteristics of the precipitates, including their type, size, number density, and distribution. The addition of copper (Cu) and scandium (Sc) was observed to have an impact on grain size refinement, while Cu addition specifically affected the precipitation behavior of the alloy. It led to remarkable changes in the number density, size, and distribution of T1 (Al2CuLi) and θ’ (Al2Cu) phases. As a result, the hardness of the alloy was significantly improved after the addition of Cu and Sc, in comparison with the base Al-Li alloy. The best heat treatment process was determined as: 580 °C/1 h solution treatment +150 °C/45 h artificial aging for Al-Li alloy and 505 °C/5 h solution treatment +180 °C/20 h artificial aging for Al-Li-Cu and Al-Li-Cu-Sc alloys.
Effects of Cold Rolling Reduction Rate on the Microstructure and Properties of Cu-1.16Ni-0.36Cr Alloy after Thermo-Mechanical Treatment
Authors: Sun Wenming , Li Shaolin , Song Kexing , Wang Qiangsong , Zhu Yingying
Published: October 2023

In this paper, a Cu-Ni-Cr alloy was prepared by adding a Ni-Cr intermediate alloy to copper. The effects of the cold rolling reduction rate on the microstructure and properties of the Cu-1.16Ni-0.36Cr alloy after thermo-mechanical treatment were studied. The results show that the tensile strength of the alloy increased while the electrical conductivity slightly decreased with an increase of the cold rolling reduction rate. At a rolling strain of 3.2, the tensile strength was 512.0 MPa and the conductivity was 45.5% IACS. At a rolling strain of 4.3, the strength further increased to 536.1 MPa and the conductivity decreased to 41.9% IACS. The grain size and dislocation density decreased with an increase of the reduction rate in the thermo-mechanical treatment. However, when the rolling strain reached 4.3, the recrystallization degree of the alloy increased due to an accumulation of the dislocation density and deformation energy, resulting in a slight increase in the grain size and a decrease in the dislocation density. The texture strength of the brass increased due to the induced shear band, with an increase of the cold rolling reduction rate. The reduction rate promoted a uniform distribution of nano-scale Cr precipitates and further enhanced the strength via precipitation strengthening.
Experimental and Numerical Investigation of Shielding Gas Behaviors in Laser Welding of TC4 Alloy
Authors: Chen Ao , Li Bingchen , Chen Xi , Jiang Meng , Zou Shuai , Tao Wang , Lei Zhenglong , Chen Yanbin
Published: October 2023

Gas protection is a crucial part of quality control in laser welding, especially for titanium alloy, which oxidizes easily at high temperatures. Substantial experiments concerning shielding gas characteristics in the welding process have been implemented. However, the common analysis conducted is simplistic and lacks a theoretical basis. This paper presented an investigation of the shielding gas behaviors based on numerical simulation and a titanium alloy laser welding experiment. The numerical model was established and validated by experiment. Subsequently, the temperature field and gas flow fields were calculated. By combining the two fields, the threshold temperature of gas protection was determined, and the influence of shielding gas parameters on the protection effect was examined. The results revealed that the protection of the high-temperature zone was primarily influenced by the nozzle height, nozzle inner diameter, and nozzle angle, while the plasma suppression effect was mainly correlated with the nozzle inner diameter and gas flow rate. These initial findings provide scientific guidance for the better quality production of laser beam welded components made of not only titanium alloy but also other metallic materials.
Solid-State Processing of CoCrMoNbTi High-Entropy Alloy for Biomedical Applications
Authors: Bololoi Alina Elena , Geambazu Laura Elena , Antoniac Iulian Vasile , Bololoi Robert Viorel , Manea Ciprian Alexandru , Cojocaru Vasile Dănuţ , Pătroi Delia
Published: October 2023

High-entropy alloys (HEAs) gained interest in the field of biomedical applications due to their unique effects and to the combination of the properties of the constituent elements. In addition to the required property of biocompatibility, other requirements include properties such as mechanical resistance, bioactivity, sterility, stability, cost effectiveness, etc. For this paper, a biocompatible high-entropy alloy, defined as bio-HEA by the literature, can be considered as an alternative to the market-available materials due to their superior properties. According to the calculation of the valence electron concentration, a majority of body-centered cubic (BCC) phases were expected, resulting in properties such as high strength and plasticity for the studied alloy, confirmed by the XRD analysis. The tetragonal (TVC) phase was also identified, indicating that the presence of face-centered cubic (FCC) phases in the alloyed materials resulted in high ductility. Microstructural and compositional analyses revealed refined and uniform metallic powder particles, with a homogeneous distribution of the elemental particles observed from the mapping analyses, indicating that alloying had occurred. The technological characterization of the high-entropy alloy-elaborated powder revealed the particle dimension reduction due to the welding and fracturing process that occurs during mechanical alloying, with a calculated average particle size of 45.12 µm.
Synthesis and Thermal Oxidation Resistance of Boron-Rich Boron–Carbide Material
Authors: Iwan Seth , Sutton Wesley , Baker Paul A. , Sereika Raimundas , Vohra Yogesh K.
Published: October 2023

A boron-rich boron–carbide material (B4+δC) was synthesized by spark plasma sintering of a ball-milled mixture of high-purity boron powder and graphitic carbon at a pressure of 7 MPa and a temperature of 1930 °C. This high-pressure, high-temperature synthesized material was recovered and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Vickers hardness measurements, and thermal oxidation studies. The X-ray diffraction studies revealed a single-phase rhombohedral structure (space group R-3m) with lattice parameters in hexagonal representation as a = 5.609 ± 0.007 Å and c = 12.082 ± 0.02 Å. The experimental lattice parameters result in a value of δ = 0.55, or the composition of the synthesized compound as B4.55C. The high-resolution scans of boron binding energy reveal the existence of a B-C bond at 188.5 eV. Raman spectroscopy reveals the existence of a 386 cm−1 vibrational mode representative of C-B-B linear chain formation due to excess boron in the lattice. The measured Vickers microhardness at a load of 200 gf shows a high hardness value of 33.8 ± 2.3 GPa. Thermal gravimetric studies on B4.55C were conducted at a temperature of 1300 °C in a compressed dry air environment, and its behavior is compared to other high-temperature ceramic materials such as high-entropy transition metal boride. The high neutron absorption cross section, high melting point, high mechanical strength, and thermal oxidation resistance make this material ideal for applications in extreme environments.
Additive Manufacturing of SS316L/IN718 Bimetallic Structure via Laser Powder Bed Fusion
Authors: Mahmud Asif , Ayers Nicolas , Huynh Thinh , Sohn Yongho
Published: October 2023

Laser powder bed fusion (LPBF) is a popular additive manufacturing (AM) technique that has demonstrated the capability to produce sophisticated engineering components. This work reports the crack-free fabrication of an SS316L/IN718 bimetallic structure via LPBF, along with compositional redistribution, phase transformations and microstructural development, and nanohardness variations. Constituent intermixing after LPBF was quantitatively estimated using thermo-kinetic coefficients of mass transport and compared with the diffusivity of Ni in the austenitic Fe-Ni system.
Influence of the Use of Transepithelial Abutments vs. Titanium Base Abutments on Microgap Formation at the Dental Implant–Abutment Interface: An In Vitro Study
Authors: Cascos Rocío , Celemín-Viñuela Alicia , Mory-Rubiños Nataly , Gómez-Polo Cristina , Ortega Rocío , Agustín-Panadero Rubén , Gómez-Polo Miguel
Published: October 2023

This in vitro study aimed to assess the presence of microgaps at the implant–abutment interface in monolithic zirconia partial implant-supported fixed prostheses on transepithelial abutments versus Ti-base abutments. Methods: Sixty conical connection dental implants were divided into two groups (n = 30). The control group consisted of three-unit bridge monolithic zirconia connected to two implants by a transepithelial abutment. The test group consisted of monolithic zirconia three-unit restoration connected to two implants directly by a titanium base (Ti-base) abutment. The sample was subjected to thermocycling (10,000 cycles at 5 °C to 55 °C, dwelling time 50 s) and chewing simulation (300,000 cycles, under 200 N at frequencies of 2 Hz, at a 30° angle). The microgap was evaluated at six points (mesiobuccal, buccal, distobuccal, mesiolingual, lingual, and distolingual) of each implant–abutment interface by using a scanning electron microscope (SEM). The data were analyzed using the Mann–Whitney U tests (p > 0.05). Results: The SEM analysis showed a smaller microgap at the implant–abutment interface in the control group (0.270 μm) than in the test group (3.902 μm). Statistically significant differences were observed between both groups (p < 0.05). Conclusions: The use or not of transepithelial abutments affects the microgap size. The transepithelial abutments group presented lower microgap values at the interface with the implant than the Ti-base group in monolithic zirconia partial implant-supported fixed prostheses. However, both groups had microgap values within the clinically acceptable range.
Efficient Graph Network Using Total Magic Labeling and Its Applications
Authors: Meenakshi Annamalai , Kannan Adhimoolam , Cep Robert , Elangovan Muniyandy
Published: October 2023

Cryptography is a pivotal application of graph theory in ensuring secure communication systems. Modern cryptography is deeply rooted in mathematical theory and computer science practices. It is widely recognized that encryption and decryption processes are primarily outcomes of mathematical research. Given the increasing importance of safeguarding secret information or messages from potential intruders, it is imperative to develop effective technical tools for this purpose. These intruders are often well-versed in the latest technological advancements that could breach security. To address this, our study focuses on the efficacious combinatorial technique of graph networks using efficient domination and total magic labeling. The introduction of a graph network based on total magic labeling can significantly influence the network’s performance. This research introduces a novel combinatorial method for encrypting and decrypting confidential numbers by leveraging an efficient dominant notion and labeled graph.
Robotic-Arm-Based Force Control by Deep Deterministic Policy Gradient in Neurosurgical Practice
Authors: Inziarte-Hidalgo Ibai , Gorospe Erik , Zulueta Ekaitz , Lopez-Guede Jose Manuel , Fernandez-Gamiz Unai , Etxebarria Saioa
Published: October 2023

This research continues the previous work “Robotic-Arm-Based Force Control in Neurosurgical Practice”. In that study, authors acquired an optimal control arm speed shape for neurological surgery which minimized a cost function that uses an adaptive scheme to determine the brain tissue force. At the end, the authors proposed the use of reinforcement learning, more specifically Deep Deterministic Policy Gradient (DDPG), to create an agent that could obtain the optimal solution through self-training. In this article, that proposal is carried out by creating an environment, agent (actor and critic), and reward function, that obtain a solution for our problem. However, we have drawn conclusions for potential future enhancements. Additionally, we analyzed the results and identified mistakes that can be improved upon in the future, such as exploring the use of varying desired distances of retraction to enhance training.
Analysis of the Influence of Calculation Parameters on the Design of the Gearbox of a High-Power Wind Turbine
Authors: Rubio Francisco , Llopis-Albert Carlos , Pedrosa Ana M.
Published: October 2023

As wind turbine power requirements have evolved from the order of kilowatts (kWs) to the order of several megawatts (MWs), wind turbine components have been subjected to more demanding and critical operating conditions. The wind turbine must cope with higher wind loads due to larger blade sizes, which are also time-varying, and, ultimately, higher power levels. One of the challenges in the manufacture of high-power wind turbines lies in the gearbox and consists of achieving ever-greater power density without compromising efficiency, i.e., greater load capacity with lower weight (and production cost) and reduced power losses. Epicyclic geartrains are used to build the gearbox due to various advantages in relation to conventional gear systems, such as higher feasible gear ratios, higher efficiency, compactnesss, and lower weight. In this paper, several epicyclic geartrains with different structures will be analysed to reveal the influence that certain design parameters have on the size and weight of the gearbox components in the selected model and, therefore, of the gearbox itself. For this purpose, the theoretical model of the gearbox will be planned and the influence of the calculation parameters on the gearbox design will be analyzed following ISO 6336. Special emphasis is placed on the influence of the material used; the modulus and tooth width on the size and weight of the gearbox will be observed. Critical stresses are also calculated. The goal is to prepare the theoretical basis for an optimization process subject to geometric, kinematic, and dynamic constraints that will result in a gearbox as compact, energy-dense, and light as possible without compromising the service life of the components.
Sobolev Estimates for the ∂¯ and the ∂¯-Neumann Operator on Pseudoconvex Manifolds
Authors: Adam Haroun Doud Soliman , Ahmed Khalid Ibrahim Adam , Saber Sayed , Marin Marin
Published: October 2023

Let D be a relatively compact domain in an n-dimensional Kähler manifold with a C2 smooth boundary that satisfies some “Hartogs-pseudoconvexity” condition. Assume that Ξ is a positive holomorphic line bundle over X whose curvature form Θ satisfies Θ≥Cω, where C>0. Then, the ∂¯-Neumann operator N and the Bergman projection P are exactly regular in the Sobolev space Wm(D,Ξ) for some m, as well as the operators ∂¯N, ∂¯⋇N.
Planar Bistable Structures Detection via the Conley Index and Applications to Biological Systems
Authors: Jia Junbo , Yang Pan , Zhu Huaiping , Jin Zhen , Duan Jinqiao , Fu Xinchu
Published: October 2023

Bistability is a ubiquitous phenomenon in life sciences. In this paper, two kinds of bistable structures in two-dimensional dynamical systems are studied: one is two one-point attractors, another is a one-point attractor accompanied by a cycle attractor. By the Conley index theory, we prove that there exist other isolated invariant sets besides the two attractors, and also obtain the possible components and their configuration. Moreover, we find that there is always a separatrix or cycle separatrix, which separates the two attractors. Finally, the biological meanings and implications of these structures are given and discussed.