bluuebunny/crossref_metadata_2025 huggingface dataset:
Green Space for Mental Health in the COVID-19 Era: A Pathway Analysis in Residential Green Space Users
Authors: Li Hansen , Browning Matthew H. E. M. , Dzhambov Angel M. , Zhang Guodong , Cao Yang
Published: July 2022

Residential green space is among the most accessible types of urban green spaces and may help maintain mental health during the COVID-19 pandemic. However, it is insufficiently understood how residents use residential green space for exercise during the epidemic. The pathways between residential green space and mental health also merit further exploration. Therefore, we conducted an online study among Chinese residents in December 2021 to capture data on engagement with urban green space for green exercise, the frequency of green exercise, perceived pollution in green space, perceptions of residential green space, social cohesion, depression, and anxiety. Among the 1208 respondents who engaged in green exercise last month, 967 (80%) reported that green exercise primarily occurred in residential neighborhoods. The rest (20%) reported that green exercise occurred in more distant urban green spaces. The most common reasons that respondents sought green exercise in urban green spaces were better air and environmental qualities. Structural equation modeling (SEM) was then employed to explore the pathways between the perceived greenness of residential neighborhoods and mental health among respondents who used residential green space for exercise. The final model suggested that residential green space was negatively associated with anxiety (β = −0.30, p = 0.001) and depression (β = −0.33, p < 0.001), mainly through indirect pathways. Perceived pollution and social cohesion were the two mediators that contributed to most of the indirect effects. Perceived pollution was also indirectly associated with green exercise through less social cohesion (β = −0.04, p = 0.010). These findings suggest a potential framework to understand the mental health benefits of residential green space and its accompanying pathways during the COVID-19 era.
Effects of Dodonaea viscosa Afforestation on Soil Nutrients and Aggregate Stability in Karst Graben Basin
Authors: Liu Lijun , Gou Guanglin , Liu Jinxia , Zhang Xuebin , Zhu Qilin , Mou Jinxia , Yang Ruoyan , Wan Yunxing , Meng Lei , Tang Shuirong , Wu Yanzheng , He Qiuxiang
Published: July 2022

Dodonaea viscosa is widely cultivated in the karst graben basin and is crucial for recovering land after rocky desertification. However, the effect of long–time D. viscosa afforestation on changes in the quality of soil remains unclear. Soil nutrients and aggregate composition can be used to evaluate the beneficial effects of afforestation of D. viscosa in improving soil functional stability. In this study, soil nutrients and aggregate stability were investigated using cropland, 10–year, 20–year, and 40–year D. viscosa afforestation and secondary succession shrub. Compared to the cropland, D. viscosa afforestation significantly increased the soil water content (WC), soil organic carbon (SOC), and total nitrogen (TN) contents, with an enhanced effect observed with prolonged afforestation. Soil nutrient contents under D. viscosa afforestation rapidly reached the level of the shrub. Dodonaea viscosa afforestation promoted the formation of >2 mm aggregates and decreased the ratio of 0.053–0.25 mm aggregates, which varied with afforestation years. Compared to the cropland, the content of >0.25 mm water–stable aggregates (R>0.25), mean weight diameter (MWD), and geometric mean weight diameter (GMD) of soil increased exponentially. However, soil erodibility factor (K) and unstable aggregates index (EIt) decreased exponentially with prolonged D. viscosa afforestation, and the latter two indicators did not reach the level of the shrub. These results indicated that soil nutrients, aggregate stability, and erosion resistance increased with prolonged D. viscosa afforestation. However, the aggregate stability and erosion resistance exhibited by D. viscosa could not reach the level of secondary shrub for a long time.
Teacher and SHL Student Beliefs about Oral Corrective Feedback: Unmasking Its Underlying Values and Beliefs
Authors: Loza Sergio
Published: July 2022

This study provides a critical discussion on oral corrective feedback (CF) in the Spanish heritage language context by analyzing the language ideologies of both teachers and students relating to this everyday pedagogical practice. Despite the undeniable relevance of oral CF within the SHL language classroom, it is an area mainly studied within the field of SLA and, thus, primarily grounded in cognitive perspectives of the individual L2 learner and their subsequent language development. Drawing on scholarship that has long contested the discrimination that U.S. Latinxs face at the macro, meso, and micro-levels of society, this study interrogates and presents the core beliefs and values that legitimize the underlying asymmetrical power relationships propagated by oral CF. As critical paradigms continue to gain currency in the field of SHL education (e.g., critical language awareness), unmasking the various ways by which monolingual ideologies operate within language education is key to developing pedagogy that promotes Spanish language maintenance and, ultimately, dismantling such structures of domination. This study focuses on exploring the ideologies about oral CF by asking: (1) What language ideologies are prevalent in relation to participants’ conceptualization of oral CF? and (2) What are the instructor’s goals for oral CF? To answer these questions, this study analyzes interview data of a language instructor (n = 1) and SHL learners (n = 4) in an elementary-level, mixed Spanish course at a Hispanic-serving community college. The results show how the instructor utilized oral CF as a mechanism to enact dominant ideologies regarding SHL learners’ non-prestige varieties, while simultaneously advocating for an approach to learners’ varieties based on appropriateness. The instructor grounded her corrective practices in beliefs and values regarding the “deficiency” of SHL learners’ cultures and social categories that she considered to be the root causes of the “problem” that SHL learners spoke non-prestige varieties of Spanish. This study sheds light on the need to reexamine current L2-based oral CF taxonomies and teaching principles that do not account for the wide-ranging ways that corrective feedback becomes entrenched in educators’ culturally shared ideologies of language, learning and the learners themselves, and as normalized by the programmatic context wherein such practices are embedded. Finally, the study concludes by proposing several guiding considerations based on CLA to develop reflective practices for pedagogues to promote a consciousness of the ideologically charged nature of CF within the SHL learning context.
Abraham Solvation Parameter Model: Examination of Possible Intramolecular Hydrogen-Bonding Using Calculated Solute Descriptors
Authors: Sinha Sneha , Yang Chelsea , Wu Emily , Acree William E.
Published: July 2022

Published solubility data for 4,5-dihydroxyanthraquinone-2-carboxylic acid dissolved in several organic solvents of varying polarity and hydrogen-bonding character are used to calculate the Abraham model solute descriptors. Calculated descriptor values suggest that 4,5-dihydroxyanthraquinone-2-carboxylic acid engages in intramolecular hydrogen formation between the two phenolic hydrogens and the proton acceptor sites (the lone electron pairs) on the neighboring quinone oxygen atom. Our study further shows that existing group contribution and machine learning methods provide rather poor estimates of the experimental-based solute descriptors of 4,5-dihydroxyanthraquinone-2-carboxylic acid, in part because the estimation methods to not account for the likely intramolecular hydrogen-bonds. The predictive aspect of the Abraham model is illustrated by predicting the solubility of 4,5-dihydroxyanthraquinone-2-carboxylic acid in 28 additional organic mono-solvents for which experimental data does not exist.
[4-(3,4-Dimethoxyphenyl)-3,6-dimethyl-2-phenyl-3,4-dihydroquinolin-1(2H)-yl)](furan-2-yl)methanone
Authors: Bonilla-Castañeda Sandra M. , Villamizar-Mogotocoro Andrés F. , Kouznetsov Vladimir V.
Published: July 2022

A N-(2,4-diaryltetrahydroquinolin-1-yl) furan-2-carboxamide derivative, [4-(3,4-dimethoxyphenyl)-3,6-dimethyl-2-phenyl-3,4-dihydroquinolin-1(2H)-yl)](furan-2-yl)methanone, was synthesized in a two-step procedure from p-toluidine, benzaldehyde, and trans-methyl-isoeugenol as commercial starting reagents through a sequence of Povarov cycloaddition reaction/N-furoylation processes. The structure of the compound was fully characterized by IR, 1H, 13C-NMR, and X-ray diffraction data. Such types of derivatives are known as relevant therapeutic agents exhibiting potent anticancer, antibacterial, antifungal, anti-inflammatory, and immunological modulator properties.
Morphological Transformation in Polymer Composite Materials Filled with Carbon Nanoparticles: Part 2—Thermal and Mechanical Properties
Authors: Ivan’kova Elena , Vaganov Gleb , Popova Elena , Yudin Vladimir
Published: July 2022

HDPE-based composite fibers filled by original and annealed carbon nanodiscs (oND and aND, respectively) were prepared by melt extrusion technology with high-temperature orientational drawing up to draw ratio DR = 8. The thermal properties of the obtained fibers were investigated by DSC and TGA methods. It was shown that the nanofillers can be influenced by high temperatures, at which the molecular mobility in the interlamellar regions became active, while the melting point and the crystallinity degree of the samples were not affected. Short- and long-term mechanical properties of the nanocomposite fibers were studied as well. Very rare mechanical testing of the knotted fibers was carried out and, as a result, a decrease of the knot strength up to 35% was detected. It was also revealed that the carbon nanodiscs do not reinforce the composite fibers and play a negative role in the creep processes, while the Young’s modulus can be improved by 2 times for the oriented samples.
Mechanical Reinforcement in Nylon 6 Nanocomposite Fiber Incorporated with Dopamine Reduced Graphene Oxide
Authors: Zhao Yonghuan , Meng Yang , Zhu Feichao , Su Juanjuan , Han Jian
Published: July 2022

The emergence of graphene-based polymer composite fibers provides a new opportunity to study the high-performance and functional chemical fibers. In this work, we have developed an efficient and convenient method with polydopamine (PDA) to functionalize and reduce graphene oxide (GO) simultaneously, and the modified graphene nanosheets can obtain uniform dispersion and strong interfacial bonding in nylon 6 (PA6). Furthermore, the reinforced PA6 composite fibers were prepared through mixing PDA-rGO into the PA6 polymer matrix and then melt spinning. The functional modification was characterized by surface analysis and structural testing including SEM, TEM, FTIR, and Raman. When the addition amount of the modified GO was 0.15 wt%, the tensile strength and Young’s modulus of the composite fiber reached 310.4 MPa and 462.3 MPa, respectively. The results showed a meaningful reinforcement with an effect compared to the pure nylon 6 fiber. Moreover, the composite fiber also exhibited an improved crystallinity and thermal stability, as measured by DSC and TGA.
Effect of Cd on Mechanical Properties of Al-Si-Cu-Mg Alloys under Different Multi-Stage Solution Heat Treatment
Authors: Mao Hongkui , Bai Xiaoyu , Song Feng , Song Yuewen , Jia Zhe , Xu Hong , Wang Yu
Published: July 2022

Multi-stage heat treatment is an important method to improve the mechanical properties of Al-Si-Cu-Mg aluminum alloys. In this paper, the multi-stage heat treatment was carried out for the Cd-free and Cd-containing alloys. The experimental results show that the addition of Cd promoted the precipitation of Q″ and θ″, which led to the formation of a large number of fine, dispersed precipitates and a higher yield strength (YS) and ultimate tensile strength (UTS) for the Cd-containing alloys. The addition of Cd also altered the optimal heat treatment parameters. For the Cd-free alloys, the Cu-rich phase fully dissolved after three-stage heat treatment, and the YS and UTS of the three-stage heat-treated alloys were higher than their two-stage heat-treated counterparts. For the Cd-containing alloys, the three-stage heat treatment led to the precipitation of Cd-rich low melting point phases, caused defects, and reduced the mechanical properties of the alloy. The size and volume fractions of the precipitates were significantly less than those of the alloys after two-stage heat treatment and the strength of the alloys decreased. Therefore, the solution time should be strictly controlled for Cd-containing Al-Si-Cu-Mg alloys.
Flexural Toughness Test and Inversion Research on a Thermal Conductivity Formula on Steel Fiber-Reinforced Concrete Components Post-Fire
Authors: Li Huayun , Chen Bingguang , Zhu Kaicheng , Gong Xiaolin
Published: July 2022

Steel fibers are widely used because they can effectively improve the tensile, compressive and flexural properties of concrete structures. The selection of steel fiber dosage and aspect ratio at high temperature has an important impact on the flexural toughness of concrete components post-fire. In this paper, discussions are made on the simulated fire test in compliance with the ISO 834 standard to study the steel fiber-reinforced concrete (SFRC) components post-fire. The research reveals the influence of two commonly used steel fiber aspect ratios (50, 70) and steel fiber dosages (30 kg/m3, 40 kg/m3, 45 kg/m3) on the changes of the internal temperature field, the initial crack flexural strength and the flexural toughness of the SFRC components under a single-side fire. Moreover, combined with the four-point flexural test of the SFRC components post fire, the research also describes the damage of high temperatures to the flexural toughness of SFRC components, and suggests a calculation formula for SFRC thermal conductivity by way of the numerical inversion method. The results of this study have verified that the incorporation of steel fiber into concrete helps to reduce its internal thermal stress difference and improve the crack resistance and fire resistance of the concrete. Moreover, under high temperature conditions, the concrete component added with the steel fiber in an aspect ratio of 70 and a dosage of 45 kg/m3 increased their initial crack flexural strength by 56.8%, higher than that of plain concrete components, and the loss of equivalent flexural strength and flexural toughness of SFRC post fire was only 45.2% and 13.6%, respectively. The proposed calculation formula of thermal conductivity can provide a reference for a numerical simulation study of the temperature field of SFRC components in a high temperature environment.
Molecular Dynamics Simulations of PtTi High-Temperature Shape Memory Alloys Based on a Modified Embedded-Atom Method Interatomic Potential
Authors: Lee Jung Soo , Chun Young-Bum , Ko Won-Seok
Published: July 2022

A new second nearest-neighbor modified embedded-atom model-based PtTi binary interatomic potential was developed by improving the pure Pt unary descriptions of the pre-existing interatomic potential. Specifically, the interatomic potential was developed focusing on the shape memory-associated phenomena and the properties of equiatomic PtTi, which has potential applications as a high-temperature shape memory alloy. The simulations using the developed interatomic potential reproduced the physical properties of the equiatomic PtTi and various intermetallic compound/alloy compositions and structures. Large-scale molecular dynamic simulations of single crystalline and nanocrystalline configurations were performed to examine the temperature- and stress-induced martensitic transformations. The results show good consistency with the experiments and demonstrate the reversible phase transformation of PtTi SMA between the cubic B2 austenite and the orthorhombic B19 martensite phases. In addition, the importance of anisotropy, constraint and the orientation of grains on the transformation temperature, mechanical response, and microstructure of SMA are presented.
Position-Sensitive Bulk and Surface Element Analysis of Decorated Porcelain Artifacts
Authors: Szentmiklósi László , Maróti Boglárka , Csákvári Szabolcs , Calligaro Thomas
Published: July 2022

Non-destructive characterization of decorated porcelain artifacts requires the joint use of surface-analytical methods for the decorative surface pattern and methods of high penetration depth for bulk-representative chemical composition. In this research, we used position-sensitive X-ray Fluorescence Spectrometry (XRF) and Prompt-gamma activation analysis (PGAA) for these purposes, assisted by 3D structured-light optical scanning and dual-energy X-ray radiography. The proper combination of the near-surface and bulk element composition data can shed light on raw material use and manufacturing technology of ceramics.
Development and Numerical Implementation of a Modified Mixed-Mode Traction–Separation Law for the Simulation of Interlaminar Fracture of Co-Consolidated Thermoplastic Laminates Considering the Effect of Fiber Bridging
Authors: Sioutis Ioannis , Tserpes Konstantinos
Published: July 2022

In the present work, a numerical model based on the cohesive zone modeling (CZM) approach has been developed to simulate mixed-mode fracture of co-consolidated low melt polyaryletherketone thermoplastic laminates by considering fiber bridging. A modified traction separation law of a tri-linear form has been developed by superimposing the bi-linear behaviors of the matrix and fibers. Initially, the data from mode I (DCB) and mode II (ENF) fracture toughness tests were used to construct the R-curves of the joints in the opening and sliding directions. The constructed curves were incorporated into the numerical models employing a user-defined material subroutine developed in the LS-Dyna finite element (FE) code. A numerical method was used to extract the fiber bridging law directly from the simulation results, thus eliminating the need for the continuous monitoring of crack opening displacement during testing. The final cohesive model was implemented via two identical FE models to simulate the fracture of a Single-Lap-Shear specimen, in which a considerable amount of fiber bridging was observed on the fracture area. The numerical results showed that the developed model presented improved accuracy in comparison to the CZM with the bi-linear traction–separation law (T–SL) in terms of the predicted strength of the joint.
Experimental Study on Durability Degradation of Geopolymer-Stabilized Soil under Sulfate Erosion
Authors: Wang Guanci , Chen Shanling , Xia Minmin , Zhong Weilin , Han Xuegang , Luo Biao , Sabri Mohanad Muayad Sabri , Huang Jiandong
Published: July 2022

In this study, the potential application of slag-fly ash-based geopolymers as stabilizers for soft soil in sulfate erosion areas was investigated to promote environmental protection and waste residue recycling. The changes in the physical and mechanical properties and microstructure characteristics of cement-stabilized soil/geopolymer-stabilized soil under sulfate erosion were comparatively studied through tests such as appearance change, mass change, strength development, and microscopic examination. The results show that the sulfate resistance of stabilized soil is significantly affected by the stabilizer type. In the sulfate environment, the cement-stabilized soil significantly deteriorates with erosion age due to the expansion stress induced by AFt, while the geopolymer-stabilized soil exhibits excellent sulfate resistance. The slag-fly ash ratio (10:0, 9:1, 8:2 and 7:3) is an important factor affecting the sulfate resistance of geopolymer-stabilized soils, and the preferred value occurs at 9:1 (G-2). When immersed for 90 d, the unconfined compressive strength value of G-2 is 7.13 MPa, and its strength retention coefficient is 86.6%. The N-A-S-H gel formed by the polymerization in the geopolymer contributes to hindering the intrusion of sulfate ions, thereby improving the sulfate resistance of stabilized soil. The research results can provide a reference for technology that stabilizes soil with industrial waste in sulfate erosion areas.
Properties of Slurry Shield Tunnel Sand and Its Application in Large Flow Concrete
Authors: Ke Zierkailedi Ba Hezhuoli , Bian Libo , Wang Xiufang , Hu Xingbo , Liu Xuelei , Zhang Zhi
Published: July 2022

The amount of Slurry shield tunnel slag (SSTS) from the Beijing East Sixth Ring Road renovation project is about 3 million m3, and it is mainly fine and silt sand. In order to realize its resource utilization, the properties of SSTS and the performance of concrete with strength grades from C30-C60, which used the mixed sand compound with SSTS and Coarse Manufactured Sand (CMS) as a fine aggregate, were investigated. The results showed that SSTS’ fineness modulus is 1.2, its clay content is 17.0% but its composition is mainly Inert Silt (IS), and SSTS replaced with 40% of the mass of CMS can obtain a mixed sand with a fineness modulus of 2.7 and a clay content of 7.0%. The morphological and filling effects of SSTS and IS will improve the workability and durability properties of concrete with no adverse effects on the compressive strength. On the other hand, clay lumps in SSTS adversely affect the workability, early cracking properties, and freeze resistance of concrete, which can be alleviated by dewatering and crushing the clay lumps in SSTS.
Photoreduction of Copper Ions Using Silica–Surfactant Hybrid and Titanium (IV) Oxide under Sulfuric Acid Conditions
Authors: Machida Shingo , Kato Reo , Hasegawa Kaishi , Gotoh Takahiro , Katsumata Ken-ichi , Yasumori Atsuo
Published: July 2022

Photoreduction of Cu2+ ions to Cu metal by titanium(IV) oxide (TiO2) was conducted in the presence of a silica–surfactant hybrid under sulfuric acid conditions. After irradiation, a dark-red color, reflections due to Cu metal in the X-ray diffraction pattern, and peaks due to Cu 2p1/2 and 2p3/2 in the X-ray photoelectron spectrum indicated the precipitation of Cu metal in the product. In addition, an increase in the Brunauer–Emmett–Teller specific surface area from 36 and 45 m2/g for the silica–surfactant and TiO2, respectively, to 591 m2/g for the product, and a decrease in the intensity of the C-H stretching band in the Fourier–transform infra-red spectra implied the removal of surfactant during the reaction. These characteristics were never observed when TiO2 was used solely. Therefore, this study indicated that the photoreduction of Cu2+ ions to Cu metal by TiO2 was facilitated under the sulfuric acid medium, where the surfactants extracted from silica–surfactant hybrids by protons in the acidic condition were successfully photo-oxidized by TiO2. Thus, this study presents a new application of the conversion of a silica–surfactant hybrid into mesoporous silicas.
Preparation and Characterization of Mesocarbon Microbeads by the Co-Polycondensation of High-Temperature Coal Tar Pitch and Coal Pyrolytic Extracts
Authors: Yan Lidong , Fang Yilin , Deng Jianfeng , Zhu Yaming , Zhang Yuzhu , Cheng Junxia , Zhao Xuefei
Published: July 2022

Mesocarbon microbeads (MCMBs) are a kind of engineering and functional artificial carbon materials generally prepared by the polymerization of polycyclic aromatic hydrocarbons. The physicochemical property of the raw materials plays a key role in the quality of MCMBs. For a detailed analysis of the synergistic effects of the generation of MCMBs, a high-temperature coal tar pitch was used as raw materials, and coal pyrolytic extracts were used as additive to synthesize the MCMBs. The microstructure and morphology of the derived MCMBs were determined by an optical microscope, scanning electron microscope, X-ray diffraction, Raman spectrum, and laser particle size analyzer. In fact, the addition of the coal pyrolytic extracts can adjust the molecular structure of the blending pitch, and the coal pyrolytic extracts can promote the generation of the MCMBs during the co-polycondensation process. The MCMBs obtained by co-polycondensation method have a good degree of sphericity, lower defects in the surface morphology, and a lower charge transfer resistance (Rct) of 4.677 Ω.
Thresholding Methods for Reduction in Data Processing Errors in the Laser-Textured Surface Topography Measurements
Authors: Podulka Przemysław
Published: July 2022

There are many factors influencing the accuracy of surface topography measurement results: one of them is the vibrations caused by the high-frequency noise occurrence. It is extremely difficult to extract results defined as noise from the real measured data, especially the application of various methods requiring skilled users and, additionally, the improper use of software may cause errors in the data processing. Accordingly, various thresholding methods for the minimization of errors in the raw surface topography data processing were proposed and compared with commonly used (available in the commercial software) techniques. Applied procedures were used for the minimization of errors in the surface topography parameters (from ISO 25178 standard) calculation after the removal and reduction, respectively, of the high-frequency noise (S-filter). Methods were applied for analysis of the laser-textured surfaces with a comparison of many regular methods, proposed previously in the commercial measuring equipment. It was found that the application of commonly used algorithms can be suitable for the processing of the measured data when selected procedures are provided. Moreover, errors in both the measurement process and the data processing can be reduced when thresholding methods support regular algorithms and procedures. From applied, commonly used methods (regular Gaussian regression filter, robust Gaussian regression filter, spline filter and fast Fourier transform filter), the most encouraging results were obtained for high-frequency noise reduction in laser-textured details when the fast Fourier transform filter was supported by a thresholding approach.
Experimental Investigation on Auto-Ignition Characteristics of Kerosene Spray Flames
Authors: Mai Zhaoming , Liu Yang , Tang Chenglong , Huang Zuohua
Published: July 2022

To facilitate the better use of RP-3 kerosene in compression ignition engines, the auto-ignition behaviors of RP-3 kerosene spray were experimentally investigated in an optical rapid compression machine. Results show that most of the tests have good ignitability and combustion performance. For all the successful ignited cases, the flame kernel was found to be formed before the steep rise of pressure, which explained that image-based ignition delay time is always shorter than the pressure-based ignition delay time. The effects of ambient environment, injection pressure, and injection delay time on the pressure history, ignition intensity, combustion duration, heat release rate, and other parameters were investigated individually. The ambient environment has a strong influence on ignition delay time by accelerating the chemical reactions, whereas the high injection pressure helps the better vaporization of fuel spray. The effect of injection delay time is non-monotonic as the trade-off relation between heat loss and blending of fuel and oxygen. The heat release rate histories under different conditions were compared and analyzed, and the two-stage heat release phenomenon was observed in the negative temperature coefficient region. The ignition intensity region was determined based on the measured ignition delay times of RP-3 kerosene spray, and multiple linear regression correlation was used to study the ignition delay time sensitivity to multi-factors.
Application of InterCriteria Analysis to Assess the Performance of Scoring Functions in Molecular Docking Software Packages
Authors: Jereva Dessislava , Alov Petko , Tsakovska Ivanka , Angelova Maria , Atanassova Vassia , Vassilev Peter , Ikonomov Nikolay , Atanassov Krassimir , Pajeva Ilza , Pencheva Tania
Published: July 2022

(1) Background: In silico approaches to rational drug design are among the fastest evolving ones. Depending on the available structural information for the biomacromolecule and the small molecule, the in silico methods are classified as ligand- and structure-based. The latter predict ligand–receptor binding using 3D structures of both molecules, whose computational simulation is referred to as molecular docking. It aims at estimating the binding affinity (approximated by scoring function) and the ligand binding pose in the receptor’s active site, which postulates a key role of the scoring functions in molecular docking algorithms. This study focuses on the performance of different types of scoring functions implemented in molecular modelling software packages. (2) Methods: An InterCriteria analysis (ICrA) was applied to assess the performance of the scoring functions available in MOE, GOLD, SeeSAR, and AutoDock Vina software platforms. The InterCriteria analysis was developed to distinguish possible relations between pairs of criteria when multiple objects are considered. All 12 investigated scoring functions were tested by docking a set of protease inhibitors in the binding sites of two protein targets. The dataset consisted of 88 benzamidine-type compounds with experimentally measured inhibitory constants for thrombin and trypsin, which allows for the objective assessment of the scoring functions performance. The results generated by the molecular docking were subjected to ICrA in order to analyze both docking energies as approximations of the binding affinities and RMSDs (root-mean-square deviation) as measures of the experimental binding pose proximity between the compounds and the co-crystalized ligand, based on the atoms in the common scaffold. (3) Results: The results obtained for the best poses, the average of the best 5 or 30 poses retained after docking, were analyzed. A comparison with the experimentally observed inhibitory effects was also performed. The InterCriteria analysis application confirms that the performance of the scoring functions for the same dataset of ligands depends on the studied protein. The analysis reveals that none of the studied scoring functions is a good predictor of the compounds’ binding affinities for the considered protein targets. (4) Conclusion: In terms of this analysis, the investigated scoring functions do not produce equivalent results, which suggests the necessity for their combined use in consensus docking studies.
The Causality Relationship between Trade and Environment in G7 Countries: Evidence from Dynamic Symmetric and Asymmetric Bootstrap Panel Causality Tests
Authors: Yılancı Veli , Çütcü İbrahim , Araci Serkan
Published: July 2022

In this paper, we test the dynamic symmetric and asymmetric causality relationship between the ecological footprint and trade openness in G7 countries by suggesting a new bootstrap panel causality test based on seemingly unrelated regressions. We analyzed the time-varying behavior of the symmetric and asymmetric panel causality relationship test to reveal the instabilities in the causality relationships. The obtained results suggest a relationship between the trade openness and ecological footprint in some years of the analysis period and between the negative and positive shocks.
Signature-Based Analysis of the Weighted-r-within-Consecutive-k-out-of-n: F Systems
Authors: Triantafyllou Ioannis S.
Published: July 2022

In the present paper, we deliver a reliability study of the weighted-r-consecutive-k-out-of-n: F reliability systems consisting of independent and identically distributed components. The signature vector of the structures is arithmetically determined by the aid of an appropriate Monte-Carlo simulation scheme. Several conclusions for the corresponding reliability polynomials are also drawn. An extensive numerical investigation is carried out to evaluate the performance of the weighted-r-consecutive-k-out-of-n: F reliability systems. Some stochastic signature-based comparisons among several members of the underlying family of reliability structures are also discussed.
Total Controllability of Non-Autonomous Measure Evolution Systems with Non-Instantaneous Impulses and State-Dependent Delay
Authors: Wang Yang , Liu Yongyang , Liu Yansheng
Published: July 2022

This paper is concerned with the existence of mild solutions and total controllability for a class of non-autonomous measure evolution systems with non-instantaneous impulses and state-dependent delay. By using the theory of evolution family and Krasnoselskii’s fixed point theorem, the existence of mild solutions and total controllability for the considered systems is obtained. Finally, we give two applications to support the validity of the study.
An Epidemic Model with Time Delay Determined by the Disease Duration
Authors: Ghosh Samiran , Volpert Vitaly , Banerjee Malay
Published: July 2022

Immuno-epidemiological models with distributed recovery and death rates can describe the epidemic progression more precisely than conventional compartmental models. However, the required immunological data to estimate the distributed recovery and death rates are not easily available. An epidemic model with time delay is derived from the previously developed model with distributed recovery and death rates, which does not require precise immunological data. The resulting generic model describes epidemic progression using two parameters, disease transmission rate and disease duration. The disease duration is incorporated as a delay parameter. Various epidemic characteristics of the delay model, namely the basic reproduction number, the maximal number of infected, and the final size of the epidemic are derived. The estimation of disease duration is studied with the help of real data for COVID-19. The delay model gives a good approximation of the COVID-19 data and of the more detailed model with distributed parameters.
Convolutional Neural Network-Based Parkinson Disease Classification Using SPECT Imaging Data
Authors: Hathaliya Jigna , Parekh Raj , Patel Nisarg , Gupta Rajesh , Tanwar Sudeep , Alqahtani Fayez , Elghatwary Magdy , Ivanov Ovidiu , Raboaca Maria Simona , Neagu Bogdan-Constantin
Published: July 2022

In this paper, we used the single-photon emission computerized tomography (SPECT) imaging technique to visualize the deficiency of dopamine-generated patterns inside the brain. These patterns are used to establish a patient’s disease progression, which helps distinguish the patients into different categories. Furthermore, we used a convolutional neural network (CNN) model to classify the patients based on the dopamine level inside the brain. The dataset used throughout this paper is the Parkinson’s progressive markers initiative (PPMI) dataset. The collected dataset was pre-processed and data amplification was performed to balance the imbalanced dataset. A CNN-based neural network was defined to classify input SPECT images into four categories. The motivation behind the proposed model is to reduce the number of resources consumed while maintaining the performance of the classification model. This will help the healthcare ecosystem run the classification model on mobile devices. The proposed model contains 14 layers with input layers, convolutional layers, max-pool layers, flatten layers, and dense layers with different dimensions. The dense layer classifies the patients into four different categories, including PSD, healthy control, scans without evidence of dopaminergic deficit (SWEDD), and GenReg PSD from the entire SPECT imaging dataset, which is used to establish the disease progression of different patients using SPECT images. The proposed model is trained with a large dataset with 58,692 images for training and 11,738 images for validation, and 7826 for testing. The proposed model outperforms the classification models from the surveyed papers. The proposed model’s accuracy is 0.889, recall is 0.9012, the precision is 0.9104, and the F1-score is 0.9057.
Mathematical Modeling and Short-Term Forecasting of the COVID-19 Epidemic in Bulgaria: SEIRS Model with Vaccination
Authors: Margenov Svetozar , Popivanov Nedyu , Ugrinova Iva , Hristov Tsvetan
Published: July 2022

Data from the World Health Organization indicate that Bulgaria has the second-highest COVID-19 mortality rate in the world and the lowest vaccination rate in the European Union. In this context, to find the crucial epidemiological parameters that characterize the ongoing pandemic in Bulgaria, we introduce an extended SEIRS model with time-dependent coefficients. In addition to this, vaccination and vital dynamics are included in the model. We construct an appropriate Cauchy problem for a system of nonlinear ordinary differential equations and prove that its unique solution possesses some biologically reasonable features. Furthermore, we propose a numerical scheme and give an algorithm for the parameters identification in the obtained discrete problem. We show that the found values are close to the parameters values in the original differential problem. Based on the presented analysis, we develop a strategy for short-term prediction of the spread of the pandemic among the host population. The proposed model, as well as the methods and algorithms for parameters identification and forecasting, could be applied to COVID-19 data in every single country in the world.
Ag/ZnO Thin Film Nanocomposite Membrane Prepared by Laser-Assisted Method for Catalytic Degradation of 4-Nitrophenol
Authors: Alrebdi Tahani A. , Ahmed Hoda A. , Alkallas Fatemah H. , Pashameah Rami Adel , Alrefaee Salhah H. , Alsubhe Emaan , Mostafa Ayman M. , Mwafy Eman A.
Published: July 2022

Zinc oxide thin film (ZnO thin film) and a silver-doped zinc oxide nanocomposite thin film (Ag/ZnO thin film) were prepared by the technique of the pulsed laser deposition at 600 °C to be applicable as a portable catalytic material for the removal of 4-nitrophenol. The nanocomposite was prepared by making the deposition of the two targets (Zn and Ag), and it was analyzed by different techniques. According to the XRD pattern, the hexagonal wurtzite crystalline form of Ag-doped ZnO NPs suggested that the samples were polycrystalline. Additionally, the shifting of the diffraction peaks to the higher angles, which denotes that doping reduces the crystallite size, illustrated the typical effect of the dopant Ag nanostructure on the ZnO thin film, which has an ionic radius less than the host cation. From SEM images, Ag-doping drastically altered the morphological characteristics and reduced the aggregation. Additionally, its energy band gap decreased when Ag was incorporated. UV spectroscopy was then used to monitor the catalysis process, and Ag/ZnO thin films had a larger first-order rate constant of the catalytic reaction K than that of ZnO thin film. According to the catalytic experiment results, the Ag/ZnO thin film has remarkable potential for use in environmentally-favorable applications.
Influence of Altered Thyroid Hormone Mechanisms in the Progression of Metabolic Dysfunction Associated with Fatty Liver Disease (MAFLD): A Systematic Review
Authors: Marschner Rafael Aguiar , Arenhardt Fernanda , Ribeiro Rafael Teixeira , Wajner Simone Magagnin
Published: July 2022

We performed a systematic review of the mechanisms of thyroid hormones (THs) associated with metabolic dysfunction associated with fatty liver disease (MAFLD). This systematic review was registered under PROSPERO (CRD42022323766). We searched the MEDLINE (via PubMed) and Embase databases from their inception to March 2022. We included studies that assessed thyroid function by measuring the serum level of THs and those involved in MAFLD. We excluded reviews, case reports, editorials, letters, duplicate studies and designed controls. Forty-three studies included MAFLD, eleven analyzed THs, and thirty-two evaluated the mechanisms of THs in MAFLD. Thyroid hormones are essential for healthy growth, development and tissue maintenance. In the liver, THs directly influence the regulation of lipid and carbohydrate metabolism, restoring the homeostatic state of the body. The selected studies showed an association of reduced levels of THs with the development and progression of MAFLD. In parallel, reduced levels of T3 have a negative impact on the activation of co-regulators in the liver, reducing the transcription of genes important in hepatic metabolism. Overall, this is the first review that systematically synthesizes studies focused on the mechanism of THs in the development and progression of MAFLD. The data generated in this systematic review strengthen knowledge of the impact of TH changes on the liver and direct new studies focusing on therapies that use these mechanisms.
Characterization of Putative Sporulation and Germination Genes in Clostridium perfringens Food-Poisoning Strain SM101
Authors: Talukdar Prabhat K. , Sarker Mahfuzur R.
Published: July 2022

Bacterial sporulation and spore germination are two intriguing processes that involve the expression of many genes coherently. Phylogenetic analyses revealed gene conservation among spore-forming Firmicutes, especially in Bacilli and Clostridia. In this study, by homology search, we found Bacillus subtilis sporulation gene homologs of bkdR, ylmC, ylxY, ylzA, ytaF, ytxC, yyaC1, and yyaC2 in Clostridium perfringenes food-poisoning Type F strain SM101. The β-glucuronidase reporter assay revealed that promoters of six out of eight tested genes (i.e., bkdR, ylmC, ytaF, ytxC, yyaC1, and yyaC2) were expressed only during sporulation, but not vegetative growth, suggesting that these genes are sporulation-specific. Gene knock-out studies demonstrated that C. perfringens ΔbkdR, ΔylmC, ΔytxC, and ΔyyaC1 mutant strains produced a significantly lower number of spores compared to the wild-type strain. When the spores of these six mutant strains were examined for their germination abilities in presence of known germinants, an almost wild-type level germination was observed with spores of ΔytaF or ΔyyaC1 mutants; and a slightly lower level with spores of ΔbkdR or ΔylmC mutants. In contrast, almost no germination was observed with spores of ΔytxC or ΔyyaC2 mutants. Consistent with germination defects, ΔytxC or ΔyyaC2 spores were also defective in spore outgrowth and colony formation. The germination, outgrowth, and colony formation defects of ΔytxC or ΔyyaC2 spores were restored when ΔytxC or ΔyyaC2 mutant was complemented with wild-type ytxC or yyaC2, respectively. Collectively, our current study identified new sporulation and germination genes in C. perfringens.
Metabolites and Their Bioactivities from the Genus Cordyceps
Authors: Qu Shuai-Ling , Li Su-Su , Li Dong , Zhao Pei-Ji
Published: July 2022

The Cordyceps genus is a group of ascomycete parasitic fungi, and all known species of this genus are endoparasites; they mainly feed on insects or arthropods and a few feed on other fungi. Fungi of this genus have evolved highly specific and complex mechanisms to escape their host’s immune system and coordinate their life cycle coefficients with those of their hosts for survival and reproduction; this mechanism has led to the production of distinctive metabolites in response to the host’s defenses. Herein, we review approximately 131 metabolites discovered in the genus Cordyceps (including mycelium, fruiting bodies and fungal complexes) in the past 15 years, which can be used as an important source for new drug research and development. We summarize chemical structures, bioactivity and the potential application of these natural metabolites. We have excluded some reports that originally belonged to Cordyceps, but whose taxonomic attribution is no longer the Cordyceps genus. This can and will serve as a resource for drug discovery.
Co–Mn Mineralisations in the Ni Laterite Deposits of Loma Caribe (Dominican Republic) and Loma de Hierro (Venezuela)
Authors: Domènech Cristina , Villanova-de-Benavent Cristina , Proenza Joaquín A. , Tauler Esperança , Lara Laura , Galí Salvador , Soler Josep M. , Campeny Marc , Ibañez-Insa Jordi
Published: July 2022

Cobalt demand is increasing due to its key role in the transition to clean energies. Although the main Co ores are the sediment-hosted stratiform copper deposits of the Democratic Republic of the Congo, Co is also a by-product of Ni–Co laterite deposits, where Co extraction efficiency depends, among other factors, on the correct identification of Co-bearing minerals. In this paper, we reported a detailed study of the Co mineralisation in the Ni–Co laterite profiles of Loma Caribe (Dominican Republic) and Loma de Hierro (Venezuela). Cobalt is mainly associated with Mn-oxyhydroxide minerals, with a composition between Ni asbolane and lithiophorite, although a Co association with phyllosilicates has also been recorded in a Loma de Hierro deposit. In Loma Caribe, Co-bearing Mn-oxyhydroxide minerals mainly developed colloform aggregates, and globular to spherulitic grains, while in Loma de Hierro, they displayed banded colloform, fibrous or tabular textures. Most of the compositional analyses of Mn-oxyhydroxides yielded 20 and 40 wt.% Mn, with Ni and Co up to 16 and 10 wt.%, respectively. In both profiles, Mn-bearing minerals were mainly found in the transition from the oxide horizon to the saprolite, as observed in other laterite profiles in the world, where the precipitation of Mn-bearing minerals is enhanced because of the pore solution saturation and pH increase.
Micro-Mechanisms and Implications of Continental Red Beds
Authors: He Wang , Yang Zhijun , Du Hengheng , Hu Jintao , Zhang Ke , Hou Weisheng , Li Hongwei
Published: July 2022

Continental red beds, widely formed at various geologic timescales, are sedimentary rocks and sediments with red as the main color. Geoscientists have analyzed the geomorphology, paleomagnetism, paleoenvironments, paleontology, energy, and minerals in continental red beds. Despite the agreement that fine-grained hematite is closely related to the color of continental red beds, controversies and problems still exist regarding the micro-mechanism of their formation. As a review, this paper details the composition and color properties of pigmentation in red beds, analyzes the existence and distribution of authigenic hematite, and summarizes the iron sources and the formation of hematite. In addition, we introduce the fading phenomenon observed in continental red beds, including three types of secondary reduction zones: reduction spots, reduction strips, and reduction areas. Lastly, this paper summarizes the evolution of color in continental red beds, emphasizes the relationship between authigenic hematite and the diagenetic environment, and proposes possible research directions for future red bed-related issues.