bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil Moisture and Water Transport through the Vadose Zone and into the Shallow Aquifer: Field Observations in Irrigated and Non-Irrigated Pasture Fields
Authors: Gómez Daniel G. , Ochoa Carlos G. , Godwin Derek , Tomasek Abigail A. , Zamora Re María I.
Published: November 2022

Reliable estimates of soil moisture and other field observations (e.g., precipitation, irrigation) are critical to quantify the seasonal variability of surface water and groundwater relationships. This is especially important in pasture-based agroecosystems that rely on surface water diversions and precipitation inputs for agricultural production. The objectives of this study were to (1) quantify soil water balance components in irrigated and non-irrigated pasture fields in western Oregon, USA and (2) evaluate soil moisture and shallow aquifer recharge relationships in irrigated vs. non-irrigated pasture fields. Four monitoring stations in each field were used to measure soil water content in the upper 0.8 m profile and shallow groundwater levels. A soil water balance (SWB) approach was used to determine deep percolation based on field measurements of several other hydrology variables (e.g., irrigation and soil moisture). The water table fluctuation method (WTFM) was used to estimate shallow aquifer response to irrigation and precipitation inputs. Results from this study add to the understanding of seasonal water transport through the vadose zone and into the shallow aquifer in agroecological systems with fine-textured soils in the Pacific Northwest region of the United States.
The Combination of Whole-Brain Features and Local-Lesion Features in DSC-PWI May Improve Ischemic Stroke Outcome Prediction
Authors: Guo Yingwei , Yang Yingjian , Wang Mingming , Luo Yu , Guo Jia , Cao Fengqiu , Lu Jiaxi , Zeng Xueqiang , Miao Xiaoqiang , Zaman Asim , Kang Yan
Published: November 2022

Accurate and reliable outcome predictions can help evaluate the functional recovery of ischemic stroke patients and assist in making treatment plans. Given that recovery factors may be hidden in the whole-brain features, this study aims to validate the role of dynamic radiomics features (DRFs) in the whole brain, DRFs in local ischemic lesions, and their combination in predicting functional outcomes of ischemic stroke patients. First, the DRFs in the whole brain and the DRFs in local lesions of dynamic susceptibility contrast-enhanced perfusion-weighted imaging (DSC-PWI) images are calculated. Second, the least absolute shrinkage and selection operator (Lasso) is used to generate four groups of DRFs, including the outstanding DRFs in the whole brain (Lasso (WB)), the outstanding DRFs in local lesions (Lasso (LL)), the combination of them (combined DRFs), and the outstanding DRFs in the combined DRFs (Lasso (combined)). Then, the performance of the four groups of DRFs is evaluated to predict the functional recovery in three months. As a result, Lasso (combined) in the four groups achieves the best AUC score of 0.971, which improves the score by 8.9% compared with Lasso (WB), and by 3.5% compared with Lasso (WB) and combined DRFs. In conclusion, the outstanding combined DRFs generated from the outstanding DRFs in the whole brain and local lesions can predict functional outcomes in ischemic stroke patients better than the single DRFs in the whole brain or local lesions.
Atranorin, a Secondary Metabolite of Lichens, Exhibited Anxiolytic/Antidepressant Activity in Wistar Rats
Authors: Urbanska Nicol , Simko Patrik , Leskanicova Andrea , Karasova Martina , Jendzelovska Zuzana , Jendzelovsky Rastislav , Rucova Dajana , Kolesarova Mariana , Goga Michal , Backor Martin , Kiskova Terezia
Published: November 2022

Atranorin (ATR) is one of lichens’ many known secondary metabolites. Most current studies have investigated the various effects of ATR in vitro and only sporadically in vivo. The latest data indicate that ATR may have anxiolytic/antidepressive effects. This study aimed to analyze the potential of ATR in a depression-like state in male Wistar rats. Pregnant females were stressed by restricting their mobility in the final week of pregnancy three times a day for 45 min each, for three following days. After birth, progeny aged 60 days was stressed repeatedly. The male progeny was divided into three groups as follows: CTR group as a healthy control (n = 10), DEP group as a progeny of restricted mothers (n = 10), and ATR group as a progeny of restricted mothers, treated daily for one month with ATR (n = 10; 10 mg/kg of body weight, p.o.). Our results show that ATR acts as an antioxidant and markedly changes animal behavior. Concomitantly, hippocampal neurogenesis increases in the hilus and subgranular zone, together with the number of NeuN mature neurons in the hilus and CA1 regions. Our results indicate a potential antidepressant/anxiolytic effect of ATR. However, further studies in this area are needed.
Chemical Profiling and Molecular Docking Study of Agathophora alopecuroides
Authors: Amin Elham , Abdel-Bakky Mohamed Sadek , Mohammed Hamdoon A. , Hassan Marwa H. A.
Published: November 2022

Natural products continue to provide inspiring chemical moieties that represent a key stone in the drug discovery process. As per our previous research, the halophyte Agathophora alopecuroides was noted as a potential antidiabetic plant. However, the chemical profiling and highlighting the metabolite(s) responsible for the observed antidiabetic activity still need to be investigated. Accordingly, the present study presents the chemical profiling of this species using the LC-HRMS/MS technique followed by a study of the ligand–protein interaction using the molecular docking method. LC-HRMS/MS results detected twenty-seven compounds in A. alopecuroides extract (AAE) belonging to variable chemical classes. Among the detected compounds, alkaloids, flavonoids, lignans, and iridoids were the most prevailing. In order to highlight the bioactive compounds in AAE, the molecular docking technique was adopted. Results suggested that the two alkaloids (Eburnamonine and Isochondrodendrine) as well as the four flavonoids (Narirutin, Pelargonidin 3-O-rutinoside, Sophora isoflavanone A, and Dracorubin) were responsible for the observed antidiabetic activity. It is worth mentioning that this is the first report for the metabolomic profiling of A. alopecuroides as well as the antidiabetic potential of Isochondrodendrine, Sophora isoflavanone A, and Dracorubin that could be a promising target for an antidiabetic drug.
Adaptation of Some Quinoa Genotypes (Chenopodium quinoa Willd.), Grown in a Saharan Climate in Algeria
Authors: Maamri Kelthoum , Zidane Ouiza Djerroudi , Chaabena Ahmed , Fiene Gabriele , Bazile Didier
Published: November 2022

Agriculture in southern Algeria faces several challenges that hinder its development, including drought, high temperatures and the excessive salinity of soil and groundwater. The introduction of crops resistant to these factors is one of the solutions chosen to address these abiotic constraints. This research aimed to evaluate the behavior of quinoa (Chenopodium Quinoa Willd.) grown in the Ouargla region of southeastern Algeria. Five varieties of quinoa (Santa maria, Giza1, Amarilla Sacaca, Blanca de Junin and Kancolla) were tested at two sites that differed in terms of soil salinity (9.95 mS/cm and 0.85 mS/cm) during 2019 and 2020. A complete random block experimental design with four repetitions was used for the agronomic tests. Our results clearly show that higher grain yields were obtained at the high salinity site (site 1) compared to the low salinity site (site 2). However, plant height, grain yield per plant and harvest index differed between varieties and sites. In contrast, stem diameter was not greatly affected by salinity. The varieties that seem to be best adapted to the growing conditions of the Ouargla region are, in descending order: Santa Maria, Giza1, Amarilla Sacaca and Blanca de Junin. When testing quinoa in new environments, it is critical to adapt the cropping cycle of varieties to avoid very high temperatures. The choice to switch to winter cultivation instead of spring cultivation can be an essential criterion for success. The biogeographical approach conducted in this research opens up new perspectives for the adaptation and cultivation of quinoa outside its region of origin to satisfy the food security of the people of North Africa.
The Molecular Mechanism of Natural Products Activating Wnt/β-Catenin Signaling Pathway for Improving Hair Loss
Authors: Shin Dong Wook
Published: November 2022

Hair loss, or alopecia, is a dermatological disorder that causes psychological stress and poor quality of life. Drug-based therapeutics such as finasteride and minoxidil have been clinically used to treat hair loss, but they have limitations due to their several side effects in patients. To solve this problem, there has been meaningful progress in elucidating the molecular mechanisms of hair growth and finding novel targets to develop therapeutics to treat it. Among various signaling pathways, Wnt/β-catenin plays an essential role in hair follicle development, the hair cycle, and regeneration. Thus, much research has demonstrated that various natural products worldwide promote hair growth by stimulating Wnt/β-catenin signaling. This review discusses the functional role of the Wnt/β-catenin pathway and its related signaling molecules. We also review the molecular mechanism of the natural products or compounds that activate Wnt/β-catenin signaling and provide insights into developing therapeutics or cosmeceuticals that treat hair loss.
Concomitant Intra-Aortic Balloon Pumping Significantly Reduces Left Ventricular Pressure during Central Veno-Arterial Extracorporeal Membrane Oxygenation—Results from a Large Animal Model
Authors: Djordjevic Ilija , Liakopoulos Oliver , Elskamp Mara , Maier-Trauth Johanna , Gerfer Stephen , Mühlbauer Thomas , Slottosch Ingo , Kuhn Elmar , Sabashnikov Anton , Rademann Pia , Maul Alexandra , Paunel-Görgülü Adnana , Wahlers Thorsten , Deppe Antje Christin
Published: November 2022

(1) Introduction: Simultaneous ECMO and IABP therapy is frequently used. Haemodynamic changes responsible for the success of the concomitant mechanical circulatory support system approach are rarely investigated. In a large-animal model, we analysed haemodynamic parameters before and during ECMO therapy, comparing central and peripheral ECMO circulation with and without simultaneous IABP support. (2) Methods: Thirty-three female pigs were divided into five groups: (1) SHAM, (2) (peripheral)ECMO(–)IABP, (3) (p)ECMO(+)IABP, (4) (central)ECMO(–)IABP, and (5) (c)ECMO(+)IABP. Pigs were cannulated in accordance with the group and supported with ECMO (±IABP) for 10 h. Systemic haemodynamics, cardiac index (CI), and coronary and carotid artery blood flow were determined before, directly after, and at five and ten hours on extracorporeal support. Systemic inflammation (IL-6; IL-10; TNFα; IFNγ), immune response (NETs; cf-DNA), and endothelial injury (ET-1) were also measured. (3) Results: IABP support during antegrade ECMO circulation led to a significant reduction of left ventricular pressure in comparison to retrograde flow in (p)ECMO(–)IABP and (p)ECMO(+)IABP. Blood flow in the left anterior coronary and carotid artery was not affected by extracorporeal circulation. (4) Conclusions: Concomitant central ECMO and IABP therapy leads to significant reduction of intracavitary cardiac pressure, reduces cardiac work, and might therefore contribute to improved recovery in ECMO patients.
Exogenous γ-Aminobutyric Acid (GABA) Application Mitigates Salinity Stress in Maize Plants
Authors: Aljuaid Bandar S. , Ashour Hatem
Published: November 2022

The effect of γ-Aminobutyrate (GABA) on maize seedlings under saline stress conditions has not been well tested in previous literature. Maize seedlings were subjected to two saline water concentrations (50 and 100 mM NaCl), with distilled water as the control. Maize seedlings under saline and control conditions were sprayed with GABA at two concentrations (0.5 and 1 mM). Our results indicated that GABA application (1 mM) significantly enhanced plant growth parameters (fresh shoots and fresh roots by 80.43% and 47.13%, respectively) and leaf pigments (chlorophyll a, b, and total chlorophyll by 22.88%, 56.80%, and 36.21%, respectively) compared to untreated seedlings under the highest saline level. Additionally, under 100 mM NaCl, methylglyoxal (MG), malondialdehyde (MDA), and hydrogen peroxidase (H2O2) were reduced by 1 mM GABA application by 43.66%, 33.40%, and 35.98%, respectively. Moreover, maize seedlings that were treated with 1 mM GABA contained a lower Na content (22.04%) and a higher K content (60.06%), compared to the control under 100 mM NaCl. Peroxidase, catalase, ascorbate peroxidase, and superoxide dismutase activities were improved (24.62%, 15.98%, 62.13%, and 70.07%, respectively) by the highest GABA rate, under the highest stress level. Seedlings treated with GABA under saline conditions showed higher levels of expression of the potassium transporter protein (ZmHKT1) gene, and lower expression of the ZmSOS1 and ZmNHX1 genes, compared to untreated seedlings. In conclusion, GABA application as a foliar treatment could be a promising strategy to mitigate salinity stress in maize plants.
Early Developmental Changes of Muscle Acetylcholine Receptors Are Little Influenced by Dystrophin Absence in mdx Mouse
Authors: Morotti Marta , Gaeta Alessandro , Limatola Cristina , Catalano Myriam , Di Castro Maria Amalia , Grassi Francesca
Published: November 2022

Dystrophin is a cytoskeletal protein contributing to the organization of the neuromuscular junction. In Duchenne muscular dystrophy, due to dystrophin absence, the distribution of endplate acetylcholine receptors (AChRs) becomes disorganized. It is still debated whether this is due to the absence of dystrophin or to the repeated damage/regeneration cycles typical of dystrophic muscle. We addressed this controversy studying the endplate in the first 3 postnatal weeks, when muscle damage in dystrophic (mdx) mice is minimal. By synaptic and extra-synaptic patch-clamp recordings in acutely dissociated mdx and wt muscle fibers, we recorded unitary events due to openings of AChR-channels containing the γ and ε subunit. We also examined AChR distribution at the endplate by immunofluorescence assays. No differences between wt and mdx fibers were found in the γ/ε switch, nor in the AChR organization at the endplates up to 21 postnatal days. Conversely, we detected a delayed appearance and disappearance of patches with high channel opening frequency in mdx fibers. Our data emphasize that the innervation-dependent γ/ε switch and AChR organization in the endplate are not affected by the absence of dystrophin, while extra-synaptic AChR cluster formation and disassembly could be differentially regulated in mdx mice.
Genital Microbiota and Outcome of Assisted Reproductive Treatment—A Systematic Review
Authors: Dube Rajani , Kar Subhranshu Sekhar
Published: November 2022

The balance between different bacterial species is essential for optimal vaginal health. Microbiome includes the host genome along with microorganism genomes and incorporates the biotic and abiotic factors, reflecting the habitat as a whole. A significant difference exists in the composition and number of the human microbiota in healthy individuals. About one-tenth of the total body microbiota exists in the urogenital tract and these can be identified by microscopy and culture-based methods, quantitative PCR, next generation and whole genome sequencing. The trend of delaying the planning of pregnancy to a later age nowadays has resulted in magnifying the use of assisted reproductive treatment (ART). Hence, genital microbiota and its impact on fertility has generated immense interest in recent years. In this systematic review, we searched the available evidence on the microbiota of the genital tract in women undergoing ART and studied the outcomes of IVF in different microbial compositions. Despite the inconsistency of the studies, it is evident that vaginal, cervical and endometrial microbiota might play a role in predicting ART outcomes. However, there is no clear evidence yet on whether the diversity, richness, quantity, or composition of species in the maternal genital tract significantly affects the outcomes in ARTs.
Nonlinear Dynamic Analysis of Gas Bearing-Rotor System by the Hybrid Method Which Combines Finite Difference Method and Differential Transform Method
Authors: Zhang Jianbo , Xie Zhongliang , Zhang Kun , Deng Zhifang , Wu Danyang , Su Zhimin , Huang Xing , Song Mingbo , Cao Yitao , Sui Jingping
Published: November 2022

Gas bearings have been widely applied to high-speed rotating machines due to their low friction and high rotational speed advantages. Nevertheless, gas lubrication is low viscosity and compressible. It causes the gas bearing-rotor system easy to produce self-excited vibration, which leads to instability of the rotor system and hinders the increase of rotor system speed. It is necessary to study the nonlinear behaviors of the aerostatic bearing-rotor system and the nonlinear vibration of the gas bearing-rotor system, especially considering the distribution mass and flexible and gyroscopic effects of the real rotor. In this paper, the nonlinear behavior of the gas bearing-rotor system is investigated from the viewpoint of nonlinear dynamics. Firstly, the dynamics model of a gas bearing rotor is established by combining the transient Reynolds equation and rotor dynamic equation obtained by finite element method (FEM). The transient Reynolds equation is solved using a hybrid method combining the differential transform method (DTM) and finite difference method (FDM). Then the transient gas force is substituted into the FEM rotor dynamic equation. In the end, based on the bifurcation diagram, the orbit of the rotor center, the frequency spectrum diagram and Poincaré map, the rotor system’s nonlinear behaviors are studied using a solution for the rotor dynamic equation with the Newmark method. Results show that there exists a limited cycle motion in the autonomous rotor system and half-speed whirl in the nonautonomous rotor system.
Nanocrystallized Surface Effect on the Tribocorrosion Behavior of AISI 420
Authors: Ben Saada Fatma , Ben Saada Mariem , Elleuch Khaled , Ponthiaux Pierre
Published: November 2022

Nanopeening treatment was applied to the AISI 420 steel to decrease its sensitivity to tribocorrosion damage. The microstructural investigation highlighted that the nanopeening treatment led to high plastic deformation and a nanostructured surface layer with a 110 µm depth. In order to study the combined effect of corrosion and mechanical wear, tribocorrosion tests were performed on non-treated and nanopeened samples in boric acid and lithium hydroxide solutions, considering both continuous and intermittent sliding. It was found that the AISI 420 steel is sensitive to the synergy between mechanical friction and electrochemical corrosion with the dominance of abrasive wear. Adhesive wear was also detected in the wear track. Indeed, the mechanical wear was pronounced under intermittent sliding because of hard wear debris generation from the repassivated layer during rotating time. The nanopeening treatment led to enhanced mechanical performance and corrosion properties. Such improvement could be explained by the high plastic deformation resulting in the nano-structuration of grains and the increasing hardness of AISI 420 steel.
Effect of Two Graphene Coatings on the Friction and Wear of Sliding Electrical Contact Interface
Authors: Wang Dongwei , Li Faqiang , Chen Xiao , Li Huaqiao , Chen Wei , Zhang Peng
Published: November 2022

Two kinds of graphene coatings are obtained by the graphene drop-coating drying method (DCDM) and the coating graphene conductive adhesive (CGCA). The effects of these two kinds of graphene coatings on the friction, wear, and voltage signals of the electrical contact interface are explored. The test results show that the presence of the graphene coating can effectively reduce the friction coefficient and friction force, and the graphene coating prepared by the DCDM possesses the best ability in reducing the friction coefficient. Although the presence of the graphene coating will lead to the increase in interface contact voltage at the initial stage, the voltage signal gradually becomes stable with the progress of friction and wear, suggesting that the graphene coating will not affect the stability of sliding electrical contact. Wear analysis results show that the graphene coating prepared by the DCDM has a good anti-wear effect, and the graphene particles in the abrasion area play the role of solid lubrication. Finite element analysis results show that the graphene coating will generate thermal expansion when electric current is applied, accordingly avoid the direct contact between the metal substrate, and, thus, reduce the interface friction and alleviate the wear degree of interface. However, the normal force fluctuation of the interface may increase.
A New Approach for the Load Calculation of the Most-Loaded Rolling Element of the Rolling Bearing with Internal Radial Clearance—A Case Study
Authors: Tomović Radoslav
Published: November 2022

One of the most important factors influencing the study of the tribological behaviour of a rolling bearing is the calculation of the loads transmitted by individual rolling elements of the bearing. However, the calculation of the internal load distribution of rolling bearings is quite complicated. It is a nonlinear, statically indeterminate problem, which can only be solved numerically, through a number of iterations. This is often a problem in analysis because it complicates the mathematical model. This paper is presenting a case study with the goal to show the benefits of the application of a new approach for the calculation of the load of the most-loaded rolling element in the rolling bearing with the internal radial clearance. The calculation is based on the so-called load factors. By multiplying the load factors with the value of the external radial load, the load that is transferred by the most-loaded rolling element of the bearing is obtained. The accuracy of the results largely depends on the correct choice of the load factor. The case study aims to define guidelines for the correct choice of load factors. The case study is made for two types of bearings: the ball bearing and the roller bearing. Obtained results were compared with the results obtained based on the calculation using some of the most commonly used methods so far. The analysis showed greater precision of the considered model with the same or much simpler use. For this reason, the proposed model is considered very suitable for practical application.
4-Methyl-7-((2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethyl)thio)-coumarin
Authors: Kurteva Vanya , Rusew Rusi , Shivachev Boris
Published: November 2022

The novel compound 4-methyl-7-((2-((5-methyl-1,3,4-thiadiazol-2-yl)thio)ethyl)thio)-coumarin is obtained in good yield via a two-step protocol; that is, initial synthesis of the reagent 2-((2-chloroethyl)thio)-5-methyl-1,3,4-thiadiazole followed by alkylation of 7-mercapto-4-methylcoumarin. The product’s structure is assigned by 1D and 2D NMR experiments and is confirmed by single-crystal XRD.
Plasmon Damping Rates in Coulomb-Coupled 2D Layers in a Heterostructure
Authors: Dahal Dipendra , Gumbs Godfrey , Iurov Andrii , Ting Chin-Sen
Published: November 2022

The Coulomb excitations of charge density oscillation are calculated for a double-layer heterostructure. Specifically, we consider two-dimensional (2D) layers of silicene and graphene on a substrate. From the obtained surface response function, we calculated the plasmon dispersion relations, which demonstrate how the Coulomb interaction renormalizes the plasmon frequencies. Most importantly, we have conducted a thorough investigation of how the decay rates of the plasmons in these heterostructures are affected by the Coulomb coupling between different types of two-dimensional materials whose separations could be varied. A novel effect of nullification of the silicene band gap is noticed when graphene is introduced into the system. To utilize these effects for experimental and industrial purposes, graphical results for the different parameters are presented.
Exosome Structures Supported by Machine Learning Can Be Used as a Promising Diagnostic Tool
Authors: Cansever Mutlu Esra , Kaya Mustafa , Küçük Israfil , Ben-Nissan Besim , Stamboulis Artemis
Published: November 2022

Principal component analysis (PCA) as a machine-learning technique could serve in disease diagnosis and prognosis by evaluating the dynamic morphological features of exosomes via Cryo-TEM-imaging. This hypothesis was investigated after the crude isolation of similarly featured exosomes derived from the extracellular vehicles (EVs) of immature dendritic cells (IDCs) JAWSII. It is possible to identify functional molecular groups by FTIR, but the unique physical and morphological characteristics of exosomes can only be revealed by specialized imaging techniques such as cryo-TEM. On the other hand, PCA has the ability to examine the morphological features of each of these IDC-derived exosomes by considering software parameters such as various membrane projections and differences in Gaussians, Hessian, hue, and class to assess the 3D orientation, shape, size, and brightness of the isolated IDC-derived exosome structures. In addition, Brownian motions from nanoparticle tracking analysis of EV IDC-derived exosomes were also compared with EV IDC-derived exosome images collected by scanning electron microscopy and confocal microscopy. Sodium-Dodecyl-Sulphate-Polyacrylamide-Gel-Electrophoresis (SDS-PAGE) was performed to separate the protein content of the crude isolates showing that no considerable protein contamination occurred during the crude isolation technique of IDC-derived-exosomes. This is an important finding because no additional purification of these exosomes is required, making PCA analysis both valuable and novel.
Uncovering the Effect of Al Addition on the Hydrogen Storage Properties of the Ternary TiVNb Alloy
Authors: Pineda-Romero Nayely , Zlotea Claudia
Published: November 2022

The effect of Al addition on the structure, microstructure and hydrogen storage properties of the ternary TiVNb alloy was investigated from small amounts to equimolar composition. Alx(TiVNb)1−x (x = 0.05, 0.175 and 0.25) alloys are bcc single-phase materials with decreasing lattice parameters with increasing Al content. Al addition progressively decreases the hydrogen storage capacity but also destabilizes fcc dihydride formation for alloys with x ≤ 0.10. Among the different compositions, the most promising alloy was found to be that with x = 0.05 Al content that exhibited high initial storage capacity (2.96 wt.%), a less stable hydride (ΔH = −52 kJ/mol H2 and ΔS = −141 J/K∙mol H2), better desorption properties (desorption onset temperature around 100 °C) and enhanced reversible capacity during cycling (2.83 wt.%) compared to the ternary TiVNb. In situ and ex situ synchrotron X-ray powder diffraction, together with thermal desorption experiments, showed improved desorption properties with Al addition, together with a two-step reaction with hydrogen. These findings highlight the use of small quantities of lightweight Al in refractory multi-principal element alloys as a promising approach for enhancing the solid-state hydrogen storage performance of bcc-type alloys.
Microstructure and Electrical Conductivity of Cement Paste Reinforced with Different Types of Carbon Nanotubes
Authors: Páez-Pavón Alicia , García-Junceda Andrea , Galán-Salazar Andrea , Merodio-Perea Rosario G. , Sánchez del Río José , Lado-Touriño Isabel
Published: November 2022

Over the last few years, the addition of small amounts of carbon nanotubes (CNTs) to construction materials has become of great interest, since it enhances some of the mechanical, electrical and thermal properties of the cement. In this sense, single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs, respectively) can be incorporated into cement to achieve the above-mentioned improved features. Thus, the current study presents the results of the addition of SWCNTs and MWCNTs on the microstructure and the physical properties of the cement paste. Density was measured through He pycnometry and the mass change was studied by thermogravimetric analysis (TGA). The microstructure and the phases were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Finally, the electrical conductivity for different CNT concentrations was measured, and an exponential increase of the conductivity with concentration was observed. This last result opens the possibility for these materials to be used in a high variety of fields, such as space intelligent systems with novel electrical and electronic applications.
Biofunctional Layered Double Hydroxide Nanohybrids for Cancer Therapy
Authors: Lee Joonghak , Seo Hee Seung , Park Wooram , Park Chun Gwon , Jeon Yukwon , Park Dae-Hwan
Published: November 2022

Layered double hydroxides (LDHs) with two-dimensional nanostructure are inorganic materials that have attractive advantages such as biocompatibility, facile preparation, and high drug loading capacity for therapeutic bioapplications. Since the intercalation chemistry of DNA molecules into the LDH materials were reported, various LDH nanohybrids have been developed for biomedical drug delivery system. For these reasons, LDHs hybridized with numerous therapeutic agents have a significant role in cancer imaging and therapy with targeting functions. In this review, we summarized the recent advances in the preparation of LDH nanohybrids for cancer therapeutic strategies including gene therapy, chemotherapy, immunotherapy, and combination therapy.
Simulation of the Kinematic Condition of Radial Shear Rolling and Estimation of Its Influence on a Titanium Billet Microstructure
Authors: Skripalenko Mikhail M. , Karpov Boris V. , Rogachev Stanislav O. , Kaputkina Liudmila M. , Romantsev Boris A. , Skripalenko Mikhail N. , Huy Tran Ba , Fadeev Viktor A. , Danilin Andrei V. , Gladkov Yuri A.
Published: November 2022

The finite element method (FEM) computer simulation of the three-high radial shear rolling of Ti-6Al-4V alloy round billets was conducted using QForm software. The simulation was performed for the MISIS-100T rolling mill’s three passes according to the following rolling route: 76 mm (the initial billet diameter) →65 mm→55 mm→48 mm (the final billet diameter). The change in the total velocity values for the points on the radius of the 48 mm diameter billet was estimated while passing the rolls’ draft. The relative increase in the accumulated strain was estimated for the same points. Then, experimental shear rolling was performed. Grain sizes of the α- and β-phases were estimated in the cross section of the final billet at the stationary stage of rolling. The grain size distribution histograms for different phases were plotted. An area was found in the billet’s cross section in which the trend of change in the total velocity of the points changed. This area represented a neutral layer between the slowing peripheral segments of the billet and the accelerating central segments of the billet. Inside this neutral layer, the limits of the cylindrical surface radius value were estimated. Experimental radial shear rolling was performed to compare the experimental rolling results (the billet microstructure investigation) with the computer simulation results. The computer simulation obtained two estimations of the radius limits: 8–16 mm (based on the analysis of the total velocity change) and 12–16 mm (based on the accumulated strain’s relative increment change). The experimental rolling obtained two more estimations of the radius limits: 8.4–19.5 mm and 11.3–19.7 mm—based on the results of the microstructure investigation. It was confirmed that varying the kinematic and deformation parameters of radial shear rolling allows regulation of the thickness of the peripheral fine-grain layer and the diameter of the central coarse-grain layer of the rolled billets.
Laboratory Study of the Effect of Zeolite and Cement Compound on the Unconfined Compressive Strength of a Stabilized Base Layer of Road Pavement
Authors: Sheikh Amin , Akbari Mahdi , Shafabakhsh Gholamali
Published: November 2022

Soil stabilization using cement is regarded as one of the conventional methods to improve the engineering properties of soil used in infrastructure and road bodies. Considering the environmental problems caused by the production and consumption of cement, finding a suitable replacement for cement is necessary. The present study aims to experimentally evaluate the effect of using zeolite instead of cement in the stabilization of pavement layers. In this research, only 5% of cement was used in the control sample, while zeolite was used instead of cement in other samples by 20, 30, 40, and 60 wt.% of cement. According to the analysis, the highest unconfined compressive strength was obtained in the sample containing 30% (wt.% of cement) of zeolite instead of cement (equivalent to 1.5% of the total stabilizing materials) after 28 days of treatment, which was 29% more than that of the sample without zeolite. Evaluating the fracture strains reveals that using zeolite instead of cement increases the fracture strain by 33%, and in other words, changes the behavior of the sample from brittle mode to soft mode.
Regulation of Structure and Anion-Exchange Performance of Layered Double Hydroxide: Function of the Metal Cation Composition of a Brucite-like Layer
Authors: Tang Luwen , Xie Xiangli , Li Cunjun , Xu Yanqi , Zhu Wenfeng , Wang Linjiang
Published: November 2022

As anion-exchange materials, layered double hydroxides (LDHs) have attracted increasing attention in the fields of selective adsorption and separation, controlled drug release, and environmental remediation. The metal cation composition of the laminate is the essential factor that determines the anion-exchange performance of LDHs. Herein, we review the regulating effects of the metal cation composition on the anion-exchange properties and LDH structure. Specifically, the internal factors affecting the anion-exchange performance of LDHs were analyzed and summarized. These include the intercalation driving force, interlayer domain environment, and LDH morphology, which significantly affect the anion selectivity, anion-exchange capacity, and anion arrangement. By changing the species, valence state, size, and mole ratio of the metal cations, the structural characteristics, charge density, and interlayer spacing of LDHs can be adjusted, which affect the anion-exchange performance of LDHs. The present challenges and future prospects of LDHs are also discussed. To the best of our knowledge, this is the first review to summarize the essential relationship between the metal ion composition and anion-exchange performance of laminates, providing important insights for regulating the anion-exchange performance of LDHs.
A Review on Resource Utilization of Spent V-W-Ti Based Selective Catalytic Reduction Catalysts
Authors: Qian Xi , Ao Weihua , Ding Hao , Wang Xuan , Sun Sijia
Published: November 2022

To address the environmental pollution caused by nitrogen oxides, V2O5-WO3/TiO2 is widely used as a catalyst based on selective catalytic reduction (SCR) technology. However, spent SCR catalysts pose a potential hazard to the environment due to the presence of heavy metals. This problem continues to plague countries with predominantly thermal power generation, and landfills as the dominant disposal method wastes significant metal resources. Previous research into the recovery of these metal resources has received considerable attention. Here, we summarise the methods of recovery and find that research trends are beginning to move towards improving the added value of recovered products. One very promising application is photocatalysts; however, the atomic efficiency of current methods is not satisfactory. Therefore, this review first focuses on the regeneration of spent SCR catalysts and the processes used for elemental extraction to clarify what forms of V, W and Ti can be obtained from existing processes. This is followed by providing directions for the conversion of spent SCR catalysts into photocatalysts with improvements based on such processes. From a different perspective, this also provides a new resource for photocatalysts and is expected to significantly reduce the cost of photocatalyst production.
Investigation of the Microstructure of Ti6Al4V Alloy by Coaxial Double Laser Metal-Wire Deposition
Authors: He Junjie , Yokota Ryosuke , Imamiya Yuji , Noriyama Keiichi , Sasahara Hiroyuki
Published: November 2022

Laser metal-wire deposition (LMwD) exhibits a larger molten pool and layer height during printing, compared to powder bed fusion additive manufacturing; in the present study, these features revealed a more inhomogeneous but easily observable microstructure. The coaxial double laser used herein makes the energy distribution of the molten pool more complex than that afforded by a single laser source, and the microstructure of the LMwD parts was more heterogeneous as well. We observed the microstructure of Ti6Al4V by the double LMwD as-built samples by conducting a laboratory experiment and a simulation. The precipitated martensite (α’) phase was defined after eliminating the influence of the β element in an X-ray diffraction analysis, which has not been discussed previously in the literature. We also propose a theory regarding the formation of heat-affected zone (HAZ) bands in an environment that includes the α’ phase. Our experiments revealed only white HAZ bands, which can be attributed to the solute partitioning caused by sequential thermal cycling and the absence of the β element. The microhardness of the HAZ band areas was lower than that of both the upper and lower sides. The simulation results indicate that the maximum temperature of 2925 °C restrains the generating of HAZ bands in the final two deposited layers, due to its great difference from the β transus temperature. Moreover, the higher heat accumulation in the upper layers promoted the migration of β-grain boundaries, which may explain why the coarse columnar β grains tended to grow at the edge area in the layers deposited later. We also observed that with the use of high temperature, the nucleation of β grains is more easily promoted in the lower layers. We conclude that the concentration of residual stress in the fusion zone and the first layer is favorable to the nucleation of equiaxed grains.
Establishment of Constitutive Model and Analysis of Dynamic Recrystallization Kinetics of Mg-Bi-Ca Alloy during Hot Deformation
Authors: Wang Qinghang , Wang Li , Zhai Haowei , Chen Yang , Chen Shuai
Published: November 2022

The flow behavior of the solution-treated Mg-3.2Bi-0.8Ca (BX31, wt.%) alloy was systematically investigated during hot compression at different deformation conditions. In the present study, the strain-related Arrhenius constitutive model and dynamic recrystallization (DRX) kinetic model were established, and the results showed that both two models had high predictability for the flow curves and the DRX behavior during hot compression. In addition, the hot processing maps were also made to confirm a suitable hot working range. Under the assistance of a hot processing map, the extrusion parameters were selected as 573 K and 0.5 mm/s. After extrusion, the as-extruded alloy exhibited a smooth surface, a fine DRX structure with weak off-basal texture and good strength–ductility synergy. The newly developed strong and ductile BX31 alloy will be helpful for enriching low-cost, high-performance wrought Mg alloy series for extensive applications in industries.
D-π-A-Type Pyrazolo[1,5-a]pyrimidine-Based Hole-Transporting Materials for Perovskite Solar Cells: Effect of the Functionalization Position
Authors: Bouihi Fatiha , Schmaltz Bruno , Mathevet Fabrice , Kreher David , Faure-Vincent Jérôme , Yildirim Ceren , Elhakmaoui Ahmed , Bouclé Johann , Akssira Mohamed , Tran-Van François , Abarbri Mohamed
Published: November 2022

Donor–acceptor (D–A) small molecules are regarded as promising hole-transporting materials for perovskite solar cells (PSCs) due to their tunable optoelectronic properties. This paper reports the design, synthesis and characterization of three novel isomeric D-π-A small molecules PY1, PY2 and PY3. The chemical structures of the molecules consist of a pyrazolo[1,5-a]pyrimidine acceptor core functionalized with one 3,6-bis(4,4′-dimethoxydiphenylamino)carbazole (3,6-CzDMPA) donor moiety via a phenyl π-spacer at the 3, 5 and 7 positions, respectively. The isolated compounds possess suitable energy levels, sufficient thermal stability (Td > 400 °C), molecular glass behavior with Tg values in the range of 127–136 °C slightly higher than that of the reference material Spiro-OMeTAD (126 °C) and acceptable hydrophobicity. Undoped PY1 demonstrates the highest hole mobility (3 × 10−6 cm2 V−1 s−1) compared to PY2 and PY3 (1.3 × 10−6 cm2 V−1 s−1). The whole isomers were incorporated as doped HTMs in planar n-i-p PSCs based on double cation perovskite FA0.85Cs0.15Pb(I0.85Br0.15)3. The non-optimized device fabricated using PY1 exhibited a power conversion efficiency (PCE) of 12.41%, similar to that obtained using the reference, Spiro-OMeTAD, which demonstrated a maximum PCE of 12.58% under the same conditions. The PY2 and PY3 materials demonstrated slightly lower performance in device configuration, with relatively moderate PCEs of 10.21% and 10.82%, respectively, and slight hysteresis behavior (−0.01 and 0.02). The preliminary stability testing of PSCs is also described. The PY1-based device exhibited better stability than the device using Spiro-OMeTAD, which could be related to its slightly superior hydrophobic character preventing water diffusion into the perovskite layer.
Dynamic Analysis of Closed Die Electromagnetic Sheet Metal Forming to Predict Deformation and Failure of AA6061-T6 Alloy Using a Fully Coupled Finite Element Model
Authors: Khan Zarak , Khan Mushtaq , Yook Se-Jin , Khan Ashfaq , Younas Muhammad , Zahir Muhammad Zeeshan , Asad Muhammad
Published: November 2022

This research presents a fully coupled 3D numerical model to analyse the dynamics of high-speed electromagnetic forming process for aluminium alloy AA6061-T6. The effect of Lorentz force distribution, velocity and kinetic energy on deformation, the bounce back effect and failure of the sheet has been investigated. Experiments were performed for AA6061-T6 alloy using an 18.750 KJ electromagnetic forming machine for varying the sheet thickness (0.5 mm, 1.02 mm and 1.63 mm) compared with the simulation results. The results showed that increasing the sheet thickness increases the Lorentz force due to a higher induced current. The inertial forces were more pronounced in thicker sheets (1.63 mm) as compared to the thinner sheets (0.5 mm and 1.02 mm), resulting in a higher bounce back effect for the thicker sheet. The numerical model accurately predicted the sheet failure for the 0.5-mm sheet, as also observed from the experimentation. The sheet deformation from simulations was found to be in good agreement with the experimental results.
Activation of Waste Materials with Carbon(IV) Oxide as an Effective Method of Obtaining Biochars of Attractive Sorption Properties towards Liquid and Gas Pollutants
Authors: Bazan-Wozniak Aleksandra , Cielecka-Piontek Judyta , Nosal-Wiercińska Agnieszka , Pietrzak Robert
Published: November 2022

Biochars that are the subjects of this report have been obtained from the residue of supercritical extraction of common nettle seeds with CO2. The residue was subjected to direct activation with carbon(IV) oxide as an activator. The obtained biochars were found to have a specific surface area inthe range of 888–1024 m2/g and a basic surface. They were used for the adsorption of a liquid organic pollutant (methylene blue) and a gas inorganic pollutant (NO2). As follows from the test results, the biochars were able to adsorb 150–239 mg of the dye. The Langmuir model was found to better describe the adsorption experimental data, while the kinetics of the process was better described by the pseudo-second-order model. From the thermodynamic analysis, it was inferred that the adsorption of methylene blue from a water solution was an endothermic and spontaneous reaction. It was established that elevated temperature of activation and the presence of air stream during adsorption had a positive impact on the adsorption of NO2 by the biochars studied. The greatest sorption capacity of the biochars towards NO2 was 59.1 mg/g.
Fatigue Characteristics of 7050-T7451 Aluminum Alloy Friction Stir Welding Joints and the Stress Ratio Effect
Authors: Zhu Hanji , Lacidogna Giuseppe , Deng Caiyan , Gong Baoming , Liu Fei
Published: November 2022

The fatigue crack initiation and growth characteristics in 7050-T7451 aluminum alloy butt joints subjected to different stress ratios and owing to friction stir welding (FSW) were investigated using fatigue tests for stress ratios of 0.1, 0.3, and 0.5. The difference between the fatigue crack initiation in the base material (BM) and FSW joints, related to coarse secondary phases, was explored using scanning electron microscopy (SEM). Accordingly, Al23CuFe4, Al7Cu2Fe, and Al2Mg3Zn3 were the preferred joint crack initiation locations, whereas Mg2Si was the major fracture initiation point of the parent material, and cracks tended to propagate along dense, coarse secondary phases, becoming more pronounced for larger cracks. In addition, as the stress ratio increased, non-Mg2Si phase fracture initiation points appeared in the BM. Meanwhile, the quantity of non-Mg2Si phases in the joints continued to increase, and the crack initiation sites became increasingly concentrated in the TMAZ-HAZ region.
SAW Hydrogen Sensors with Pd/SnO2 Layers
Authors: Constantinoiu Izabela , Miu Dana , Viespe Cristian
Published: November 2022

Pd/SnO2 bilayers for surface acoustic wave (SAW) sensors were obtained using pulsed laser deposition (PLD). Bilayers were made at several deposition pressures in order to observe the influence of the morphology of the sensitive films on the response of the sensors. The morphological properties were analyzed by scanning electron microscopy (SEM). The SnO2 monolayers were initially deposited on quartz substrates at 100, 400 and 700 mTorr, to observe their morphology at these pressures. The Pd/SnO2 bilayer depositions were made at 100 and 700 mTorr. The sensors realized with these sensitive films were tested at different hydrogen concentrations, in the range of 0.2–2%, at room temperature. In order to establish selectivity, tests for hydrogen, nitrogen, oxygen and carbon dioxide were carried out with SnO2-700, Pd-100/SnO2-700 and Pd-700/SnO2-700 sensors. The sensor with the most porous sensitive film (both films deposited at 700 mTorr) had the best results: a sensitivity of 0.21 Hz/ppm and a limit of detection (LOD) of 142 ppm. The morphology of the SnO2 film is the one that has the major influence on the sensor results, to the detriment of the Pd morphology. The use of Pd as a catalyst for hydrogen improved the sensitivity of the film considerably and the selectivity of the sensors for hydrogen.