bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of p-Coumaric Acid Analysis in Human Plasma and Its Clinical Application to PK/PD Study
Authors: Kim Hohyun , Choi Yunkyoung , An Yongwun , Jung Young-Rim , Lee Jin-Yong , Lee Hong-Jin , Jeong Jihoon , Kim Zisoo , Kim Kyeongsoon
Published: December 2020

It has been recognized that p-Coumaric acid (p-CA) has protective effects as an antioxidant, anti-inflammatory agent. A sensitive and efficient Liquid Chromatography-Mass Spectrometry (LC-MS) method for maximum determination of p-CA in human plasma has been established using Ultra-performance liquid Chromatography-tandem mass Spectrometry (UPLC-MS/MS). This study provides the developed analysis of p-CA extracted from Bambusae Caulis in Taeniam (BC) to examine the improvement of the treatment p-CA, IGF-1 and Osteocalcin level in human children which are important factors on the growth of children’s height through Pharmacokinetics/Pharmacodynamics (PK/PD) model. p-CA and internal standard in a plasma sample were detected by the Multiple Reaction Monitoring (MRM) scan mode with positive ion detection. The sample participating in the study was made of 34 subjects (placebo = 18, treatment = 16). The subjects were enrolled to be randomized to the control group and BC group. Randomized subjects took tested treatment twice a day, three capsules with oral administration (258 mg/capsule) each time after a meal. Standard calibration curves (reproducibility) were constructed and the lower limit of quantitation (LLOQ) for p-CA was found to be 0.2 ng/mL on injection of the sample into the UPLC-MS/MS system. Accuracy and precision were evaluated and the intra-accuracy was 99.2–103.8% with precision of 1.0–5.6% and inter-accuracy was 99.6–108.4% and precision of 1.3–6.4% for p-CA. The method has been successfully applied to PK/PD studies of p-CA in human plasma. The p-CA, BC in Taeniam extract increased the level of IGF-1 and Osteocalcin, and changed the height from baseline, which suggested that the p-CA could play an important role in longitudinal bone growth. Therefore, the p-CA extracted from BC in Taeniam might be a good alternative medicine to growth hormone (GH) therapy.
Blockchain and IoMT against Physical Abuse: Bullying in Schools as a Case Study
Authors: Ersotelos Nikolaos , Bottarelli Mirko , Al-Khateeb Haider , Epiphaniou Gregory , Alhaboby Zhraa , Pillai Prashant , Aggoun Amar
Published: December 2020

By law, schools are required to protect the well-being of students against problems such as on-campus bullying and physical abuse. In the UK, a report by the Office for Education (OfE) showed 17% of young people had been bullied during 2017–2018. This problem continues to prevail with consequences including depression, anxiety, suicidal thoughts, and eating disorders. Additionally, recent evidence suggests this type of victimisation could intensify existing health complications. This study investigates the opportunities provided by Internet of Medical Things (IoMT) data towards next-generation safeguarding. A new model is developed based on blockchain technology to enable real-time intervention triggered by IoMT data that can be used to detect stressful events, e.g., when bullying takes place. The model utilises private permissioned blockchain to manage IoMT data to achieve quicker and better decision-making while revolutionising aspects related to compliance, double-entry, confidentiality, and privacy. The feasibility of the model and the interaction between the sensors and the blockchain was simulated. To facilitate a close approximation of an actual IoMT environment, we clustered and decomposed existing medical sensors to their attributes, including their function, for a variety of scenarios. Then, we demonstrated the performance and capabilities of the emulator under different loads of sensor-generated data. We argue to the suitability of this emulator for schools and medical centres to conduct feasibility studies to address sensor data with disruptive data processing and management technologies.
Making the Third Dimension (3D) Explicit in Hedonic Price Modelling: A Case Study of Xi’an, China
Authors: Ying Yue , Koeva Mila , Kuffer Monika , Asiama Kwabena Obeng , Li Xia , Zevenbergen Jaap
Published: December 2020

Recent rapid population growth and increasing urbanisation have led to fast vertical developments in urban areas. Therefore, in the context of the dynamic property market, factors related to the third dimension (3D) need to be considered. Current hedonic price modelling (HPM) studies have little explicit consideration for the third dimension, which may have a significant influence on modelling property values in complex urban environments. Therefore, our research aims to narrow the cognitive gap of the missing third dimension by assessing both 2D and 3D HPM and identifying important 3D factors for spatial analysis and visualisation in the selected study area, Xi’an, China. The statistical methods we used for 2D HPM are ordinary least squares (OLS) and geographically weighted regression (GWR). In 2D HPM, they both have very low R2 (0.111 in OLS and 0.217 in GWR), showing a very limited generalisation potential. However, a significant improvement is observed when adding 3D factors, namely view quality, sky view factor (SVF), sunlight and property orientation. The obtained higher R2 (0.414) shows the importance of the third dimension or—3D factors for HPM. Our findings demonstrate the necessity to include such factors into HPM and to develop 3D models with a higher level of details (LoD) to serve more purposes such as fair property taxation.
Gender Bias in Indonesian Courts: Is Perma No. 3 of 2017 the Solution for Gender-Based Violence Cases?
Authors: Saraswati Rika
Published: December 2020

To support women who are dealing with the legal system, especially women victims of gender-based violence, the Indonesian government issued Supreme Court Regulation (Perma) No. 3 of 2017 on Guidelines for Judging Cases of Women in Conflict with the Law. This regulation deals with women as victims, defendants and witnesses, and is used for civil and criminal cases. The Perma appears to attempt to counterbalance existing discriminatory practices in the courts and their processes. This article discusses the effectiveness of the “special treatment” in Supreme Court Regulation (Perma) No. 3 of 2017 on Guidelines for Judging Cases of Women in Conflict with the Law. This Perma seems to provide hope for producing progressive court decisions by contributing to the elimination of discrimination against women in the court process. However, this expectation certainly needs to be reviewed, given that, in their entirety, any such proceedings involve not only judges but also other law enforcement officials, namely the prosecutors. Furthermore, the presence of this Perma is considered by some Indonesian feminists to contradict the Judicial Code of Ethics and Guidelines for Judicial Behaviour (“the Code”). The Code requires judges to be neutral in judging but this Perma demands the opposite. This study is a qualitative study, and the data is obtained through a literature study of research conducted on court decisions and gender-based violence cases involving Indonesian women.
Nitrogen-Based Heterocyclic Compounds: A Promising Class of Antiviral Agents against Chikungunya Virus
Authors: Santana Andreza C. , Silva Filho Ronaldo C. , Menezes José C. J. M. D. S. , Allonso Diego , Campos Vinícius R.
Published: December 2020

Arboviruses, in general, are a global threat due to their morbidity and mortality, which results in an important social and economic impact. Chikungunya virus (CHIKV), one of the most relevant arbovirus currently known, is a re-emergent virus that causes a disease named chikungunya fever, characterized by a severe arthralgia (joint pains) that can persist for several months or years in some individuals. Until now, no vaccine or specific antiviral drug is commercially available. Nitrogen heterocyclic scaffolds are found in medications, such as aristeromycin, favipiravir, fluorouracil, 6-azauridine, thioguanine, pyrimethamine, among others. New families of natural and synthetic nitrogen analogous compounds are reported to have significant anti-CHIKV effects. In the present work, we focus on these nitrogen-based heterocyclic compounds as an important class with CHIKV antiviral activity. We summarize the present understanding on this class of compounds against CHIKV and also present their possible mechanism of action.
Simulation of Dynamic and Meta-Dynamic Recrystallization Behavior of Forged Alloy 718 Parts Using a Multi-Class Grain Size Model
Authors: Gruber Christian , Raninger Peter , Stanojevic Aleksandar , Godor Flora , Rath Markus , Kozeschnik Ernst , Stockinger Martin
Published: December 2020

Dynamic and meta-dynamic recrystallization occur during forging of alloy 718 aircraft parts and thus change the microstructure during a multistep production route. Since the prediction of the resulting grain structure in a single grain fraction is not able to describe microstructures with bimodal or even multimodal distributions, a multi-class grain size model has been deployed to describe the recrystallization mechanisms during thermomechanical treatments and predict the resulting grain size distributions more accurately. As forging parameters, such as temperature, strain rate and maximum strain influence the flow curve and consequently the recrystallization behavior, a series of double cone compression experiments has been carried out and used to verify and adapt the material parameters for the multi-class grain size model. The recrystallized fractions of the numerical and experimental results are compared and differentiated in view of the recrystallization mechanism, i.e., dynamic and meta-dynamic recrystallization. The strong dependence of the recrystallization kinetics on the initial grain size is highlighted, as well as the influence of different strain rates, which shall represent typical forging equipment.
Exploration of Free Energy Surface and Thermal Effects on Relative Population and Infrared Spectrum of the Be6B11− Fluxional Cluster
Authors: Buelna-Garcia Carlos Emiliano , Cabellos José Luis , Quiroz-Castillo Jesus Manuel , Martinez-Guajardo Gerardo , Castillo-Quevedo Cesar , de-Leon-Flores Aned , Anzueto-Sanchez Gilberto , Martin-del-Campo-Solis Martha Fabiola
Published: December 2020

The starting point to understanding cluster properties is the putative global minimum and all the nearby local energy minima; however, locating them is computationally expensive and difficult. The relative populations and spectroscopic properties that are a function of temperature can be approximately computed by employing statistical thermodynamics. Here, we investigate entropy-driven isomers distribution on Be6B11− clusters and the effect of temperature on their infrared spectroscopy and relative populations. We identify the vibration modes possessed by the cluster that significantly contribute to the zero-point energy. A couple of steps are considered for computing the temperature-dependent relative population: First, using a genetic algorithm coupled to density functional theory, we performed an extensive and systematic exploration of the potential/free energy surface of Be6B11− clusters to locate the putative global minimum and elucidate the low-energy structures. Second, the relative populations’ temperature effects are determined by considering the thermodynamic properties and Boltzmann factors. The temperature-dependent relative populations show that the entropies and temperature are essential for determining the global minimum. We compute the temperature-dependent total infrared spectra employing the Boltzmann factor weighted sums of each isomer’s infrared spectrum and find that at finite temperature, the total infrared spectrum is composed of an admixture of infrared spectra that corresponds to the spectra of the lowest-energy structure and its isomers located at higher energies. The methodology and results describe the thermal effects in the relative population and the infrared spectra.
Hardening of Additive Manufactured 316L Stainless Steel by Using Bimodal Powder Containing Nanoscale Fraction
Authors: Filimonov Aleksandr M. , Rogozin Oleg A. , Firsov Denis G. , Kuzminova Yulia O. , Sergeev Semen N. , Zhilyaev Alexander P. , Lerner Marat I. , Toropkov Nikita E. , Simonov Alexey P. , Binkov Ivan I. , Okulov Ilya V. , Akhatov Iskander S. , Evlashin Stanislav A.
Published: December 2020

The particle size distribution significantly affects the material properties of the additively manufactured parts. In this work, the influence of bimodal powder containing nano- and micro-scale particles on microstructure and materials properties is studied. Moreover, to study the effect of the protective atmosphere, the test samples were additively manufactured from 316L stainless steel powder in argon and nitrogen. The samples fabricated from the bimodal powder demonstrate a finer subgrain structure, regardless of protective atmospheres and an increase in the Vickers microhardness, which is in accordance with the Hall-Petch relation. The porosity analysis revealed the deterioration in the quality of as-built parts due to the poor powder flowability. The surface roughness of fabricated samples was the same regardless of the powder feedstock materials used and protective atmospheres. The results suggest that the improvement of mechanical properties is achieved by adding a nano-dispersed fraction, which dramatically increases the total surface area, thereby contributing to the nitrogen absorption by the material.
Correction: Quevillon, M.J., et al. Charge Transport and Phase Behavior of Imidazolium-Based Ionic Liquid Crystals from Fully Atomistic Simulations. Materials 2018, 11, 64
Authors: Quevillon Michael J. , Whitmer Jonathan K.
Published: December 2020

In our publication [...]
Na0.76V6O15/Activated Carbon Hybrid Cathode for High-Performance Lithium-Ion Capacitors
Authors: Lu Renwei , Ren Xiaolong , Wang Chong , Zhan Changzhen , Nan Ding , Lv Ruitao , Shen Wanci , Kang Feiyu , Huang Zheng-Hong
Published: December 2020

Lithium-ion hybrid capacitors (LICs) are regarded as one of the most promising next generation energy storage devices. Commercial activated carbon materials with low cost and excellent cycling stability are widely used as cathode materials for LICs, however, their low energy density remains a significant challenge for the practical applications of LICs. Herein, Na0.76V6O15 nanobelts (NaVO) were prepared and combined with commercial activated carbon YP50D to form hybrid cathode materials. Credit to the synergism of its capacitive effect and diffusion-controlled faradaic effect, NaVO/C hybrid cathode displays both superior cyclability and enhanced capacity. LICs were assembled with the as-prepared NaVO/C hybrid cathode and artificial graphite anode which was pre-lithiated. Furthermore, 10-NaVO/C//AG LIC delivers a high energy density of 118.9 Wh kg−1 at a power density of 220.6 W kg−1 and retains 43.7 Wh kg−1 even at a high power density of 21,793.0 W kg−1. The LIC can also maintain long-term cycling stability with capacitance retention of approximately 70% after 5000 cycles at 1 A g−1. Accordingly, hybrid cathodes composed of commercial activated carbon and a small amount of high energy battery-type materials are expected to be a candidate for low-cost advanced LICs with both high energy density and power density.
Investigation of the Erosion Damage Mechanism and Erosion Prediction of Boronized Coatings at Elevated Temperatures
Authors: Cai Liu-Xi , Li Yun , Wang Shun-Sen , He Yao , Li Fang , Liu Ze-Kun
Published: December 2020

In this study, the high temperature erosion mechanisms and damage characteristics of a boronized coating have been systematically studied by employing an improved high-temperature accelerated erosion test bench and impact contact theory analyses. Within the scope of the experimental parameters, the erosion rate of the boronized coating under the same erosion conditions was observed to be only one half to one-twelfth of the erosion rate of the substrate. Furthermore, the boronized coating was noted to be less sensitive to the speed of the erosion particles than the plastic substrate, thus, indicating superior and more stable erosion resistance than the base material. The boronized coating exhibited typical brittle fracture characteristics under impact by the high-speed particles. When the particle impact normal stress exceeded the critical stress for crack propagation owing to the coating defects, the surface and subsurface layers of the coating initially formed horizontal and vertical micro-cracks, followed by their gradual expansion and intersection. After destabilization, the brittle coating material was peeled layer-by-layer from the surface of the test piece. At the same incident speed, as the particle size was increased from 65 μm to 226 μm and 336 μm, the size (width) of the erosion cracks on the coating surface increased from 1 μm to 30 μm and 100 μm respectively. Correspondingly, the erosion damage thickness of the coating was enhanced from 15 μm to 50 μm and 100 μm. In the case of the quartz sand particle size exceeding 300 μm, the dual-phase boronized coating did not provide effective protection to the substrate. Furthermore, based on the elastoplastic fracture theory, a prediction model for the erosion weight loss of the boronized coatings within the effective thickness range has been proposed in this study.
Assessment of Mechanical, Chemical, and Biological Properties of Ti-Nb-Zr Alloy for Medical Applications
Authors: Hoppe Viktoria , Szymczyk-Ziółkowska Patrycja , Rusińska Małgorzata , Dybała Bogdan , Poradowski Dominik , Janeczek Maciej
Published: December 2020

The purpose of this work is to obtain comprehensive reference data of the Ti-13Nb-13Zr alloy base material: its microstructure, mechanical, and physicochemical properties. In order to obtain extensive information on the tested materials, a number of examination methods were used, including SEM, XRD, and XPS to determine the phases occurring in the material, while mechanical properties were verified with static tensile, compression, and bending tests. Moreover, the alloy’s corrosion resistance in Ringer’s solution and the cytotoxicity were investigated using the MTT test. Studies have shown that this alloy has the structure α’, α, and β phases, indicating that parts of the β phase transformed to α’, which was confirmed by mechanical properties and the shape of fractures. Due to the good mechanical properties (E = 84.1 GPa), high corrosion resistance, as well as the lack of cytotoxicity on MC3T3 and NHDF cells, this alloy meets the requirements for medical implant materials. Ti-13Nb-13Zr alloy can be successfully used in implants, including bone tissue engineering products and dental applications.
Fabrication of SiC Sealing Cavity Structure for All-SiC Piezoresistive Pressure Sensor Applications
Authors: Zhao Lihuan , Shang Haiping , Wang Dahai , Liu Yang , Tian Baohua , Wang Weibing
Published: December 2020

High hardness and corrosion resistance of SiC (silicon carbide) bulk materials have always been a difficult problem in the processing of an all-SiC piezoresistive pressure sensor. In this work, we demonstrated a SiC sealing cavity structure utilizing SiC shallow plasma-etched process (≤20 μm) and SiC–SiC room temperature bonding technology. The SiC bonding interface was closely connected, and its average tensile strength could reach 6.71 MPa. In addition, through a rapid thermal annealing (RTA) experiment of 1 min and 10 mins in N2 atmosphere of 1000 °C, it was found that Si, C and O elements at the bonding interface were diffused, while the width of the intermediate interface layer was narrowed, and the tensile strength could remain stable. This SiC sealing cavity structure has important application value in the realization of an all-SiC piezoresistive pressure sensor.
On the Weldability of Thick P355NL1 Pressure Vessel Steel Plates Using Laser Welding
Authors: Čapek Jiří , Trojan Karel , Kec Jan , Černý Ivo , Ganev Nikolaj , Němeček Stanislav
Published: December 2020

Pipeline transport uses millions of kilometers of pipes worldwide to transport liquid or gas over long distances to the point of consumption. High demands are placed, especially on the transport of hazardous substances under high pressure (gas, oil, etc.). Mostly seamless steel pipes of various diameters are used, but their production is expensive. The use of laser-welded pipes could significantly reduce the cost of building new pipelines. However, sufficient mechanical properties need to be ensured for welded pipes to meet stringent requirements. Therefore, laser-welded 10 mm thick pressure vessel steel plates were subjected to various mechanical tests, including high-cycle fatigue tests. Furthermore, the microstructural parameters and the state of residual stresses were determined using X-ray and neutron diffraction, which could affect fatigue life, too. The critical areas for possible crack initialization, especially in and near the heat-affected zone, were found using different tests. The presented results outline the promising application potential of laser welding for the production of pipes for high-pressure pipelines.
Transient Thermomechanical Simulation of 7075 Aluminum Contraction around a SiO2 Microparticle
Authors: Tamayo-Meza Pedro Alejandro , Cerro-Ramírez Miguel Ángel , Merchán-Cruz Emmanuel Alejandro , Silva-Rivera Usiel Sandino , Rivera-Blas Raúl , Flores-Herrera Luis Armando
Published: December 2020

One important challenge that faces the metallurgic industry turns around the constant increment in the mechanical resistance of certain finished products. Metallurgic advantages can be obtained from the inclusion of microparticles in metallic materials, but this inclusion involves complex challenges as the internal stress distribution can be modified. In this work, the simulation of a cooling sequence in 7075 aluminum with a SiO2 microparticle is presented. Two models of two-dimensional (2D) type were constructed in ANSYS®2019 with circular and oval shape microparticles located inside the aluminum. Both models were subjected to the same thermomechanical transient analysis to compare the remaining stress distributions around the microparticles after the thermal load and to observe the effect of the geometrical shape. The results show remaining stresses increased in the oval model as a consequence of the geometrical shape modification. After applying a tension load in the analyzed specimens, shear stress concentrations were observed with a higher magnitude around the covertex of the oval shape. The results can be very useful for the creation of materials with controlled remnant stress located in specific or desired locations in the matrix.
Exchange Market Liquidity Prediction with the K-Nearest Neighbor Approach: Crypto vs. Fiat Currencies
Authors: Cortez Klender , Rodríguez-García Martha del Pilar , Mongrut Samuel
Published: December 2020

In this paper, we compare the predictions on the market liquidity in crypto and fiat currencies between two traditional time series methods, the autoregressive moving average (ARMA) and the generalized autoregressive conditional heteroskedasticity (GARCH), and the machine learning algorithm called the k-nearest neighbor (KNN) approach. We measure market liquidity as the log rates of bid-ask spreads in a sample of three cryptocurrencies (Bitcoin, Ethereum, and Ripple) and 16 major fiat currencies from 9 February 2018 to 8 February 2019. We find that the KNN approach is better suited for capturing the market liquidity in a cryptocurrency in the short-term than the ARMA and GARCH models maybe due to the complexity of the microstructure of the market. Considering traditional time series models, we find that ARMA models perform well when estimating the liquidity of fiat currencies in developed markets, whereas GARCH models do the same for fiat currencies in emerging markets. Nevertheless, our results show that the KNN approach can better predict the log rates of the bid-ask spreads of crypto and fiat currencies than ARMA and GARCH models.
On the Growth of Higher Order Complex Linear Differential Equations Solutions with Entire and Meromorphic Coefficients
Authors: Sánchez Ruiz Luis Manuel , Datta Sanjib Kumar , Tamang Samten , Biswas Nityagopal
Published: December 2020

We revisit the problem of studying the solutions growth order in complex higher order linear differential equations with entire and meromorphic coefficients of p,q-order, proving how it is related to the growth of the coefficient of the unknown function under adequate assumptions. Our study improves the previous results due to J. Liu - J. Tu - L. Z Shi, L.M. Li - T.B. Cao, and others.
Concurrent Vector Fields on Lightlike Hypersurfaces
Authors: Kılıç Erol , Gülbahar Mehmet , Kavuk Ecem
Published: December 2020

Concurrent vector fields lying on lightlike hypersurfaces of a Lorentzian manifold are investigated. Obtained results dealing with concurrent vector fields are discussed for totally umbilical lightlike hypersurfaces and totally geodesic lightlike hypersurfaces. Furthermore, Ricci soliton lightlike hypersurfaces admitting concurrent vector fields are studied and some characterizations for this frame of hypersurfaces are obtained.
Assessment of Students’ Achievements and Competencies in Mathematics Using CART and CART Ensembles and Bagging with Combined Model Improvement by MARS
Authors: Gocheva-Ilieva Snezhana , Kulina Hristina , Ivanov Atanas
Published: December 2020

The aim of this study is to evaluate students’ achievements in mathematics using three machine learning regression methods: classification and regression trees (CART), CART ensembles and bagging (CART-EB) and multivariate adaptive regression splines (MARS). A novel ensemble methodology is proposed based on the combination of CART and CART-EB models in a new ensemble to regress the actual data using MARS. Results of a final exam test, control and home assignments, and other learning activities to assess students’ knowledge and competencies in applied mathematics are examined. The exam test combines problems on elements of mathematical analysis, statistics and a small practical project. The project is the new competence-oriented element, which requires students to formulate problems themselves, to choose different solutions and to use or not use specialized software. Initially, empirical data are statistically modeled using six CART and six CART-EB competing models. The models achieve a goodness-of-fit up to 96% to actual data. The impact of the examined factors on the students’ success at the final exam is determined. Using the best of these models and proposed novel ensemble procedure, final MARS models are built that outperform the other models for predicting the achievements of students in applied mathematics.
Genomics- and Metabolomics-Based Investigation of the Deep-Sea Sediment-Derived Yeast, Rhodotorula mucilaginosa 50-3-19/20B
Authors: Buedenbender Larissa , Kumar Abhishek , Blümel Martina , Kempken Frank , Tasdemir Deniz
Published: December 2020

Red yeasts of the genus Rhodotorula are of great interest to the biotechnological industry due to their ability to produce valuable natural products, such as lipids and carotenoids with potential applications as surfactants, food additives, and pharmaceuticals. Herein, we explored the biosynthetic potential of R. mucilaginosa 50-3-19/20B collected from the Mid-Atlantic Ridge using modern genomics and untargeted metabolomics tools. R. mucilaginosa 50-3-19/20B exhibited anticancer activity when grown on PDA medium, while antimicrobial activity was observed when cultured on WSP-30 medium. Applying the bioactive molecular networking approach, the anticancer activity was linked to glycolipids, namely polyol esters of fatty acid (PEFA) derivatives. We purified four PEFAs (1–4) and the known methyl-2-hydroxy-3-(1H-indol-2-yl)propanoate (5). Their structures were deduced from NMR and HR-MS/MS spectra, but 1–5 showed no anticancer activity in their pure form. Illumina-based genome sequencing, de novo assembly and standard biosynthetic gene cluster (BGC) analyses were used to illustrate key components of the PEFA biosynthetic pathway. The fatty acid producing BGC3 was identified to be capable of producing precursors of PEFAs. Some Rhodotorula strains are able to convert inulin into high-yielding PEFA and cell lipid using a native exo-inulinase enzyme. The genomic locus for an exo-inulinase enzyme (g1629.t1), which plays an instrumental role in the PEFA production via the mannitol biosynthesis pathway, was identified. This is the first untargeted metabolomics study on R. mucilaginosa providing new genomic insights into PEFA biosynthesis.
On the Friction Stir Welding of Al 7075 Thin Sheets
Authors: Dimopoulos Andreas , Vairis Achilles , Vidakis Nectarios , Petousis Markos
Published: December 2020

The aim of this work was to weld thin sheets (2 mm) of Al 7075 in a butt joint configuration using friction stir welding and to identify the appropriate tool geometry and optimum process parameters. Two tools were produced with heat treatable low alloy steel WNr 1.6582/DIN 34CrNiMo6 with a different pin diameter (3 mm and 4 mm). Welding was performed at a range of rotation speeds 1000–2500 rpm and various welding speeds 80–800 mm/min. The tensile strength was measured to evaluate mechanical properties. Results showed that despite the difficulties in friction stir welding thin plates, sound joints can be produced in a repeatable manner, without visible wear on the welding tool. The mechanical strength of the welds showed a decrease (33.75%) over that of the parent material. The mechanical strength was less affected by rotation speed than welding speed and there was a significant decrease in tensile strength compared to the parent material.
Effect of Cavitation Peening on Fatigue Properties in Friction Stir Welded Aluminum Alloy AA5754
Authors: Soyama Hitoshi , Simoncini Michela , Cabibbo Marcello
Published: December 2020

Friction stir welding (FSW) is an attractive solid-state joining technique for lightweight metals; however, fatigue properties of FSWed metals are lower than those of bulk metals. A novel mechanical surface treatment using cavitation impact, i.e., cavitation peening, can improve fatigue life and strength by introducing compressive residual stress into the FSWed part. To demonstrate the enhancement of fatigue properties of FSWed metal sheet by cavitation peening, aluminum alloy AA5754 sheet jointed by FSW was treated by cavitation peening using cavitating jet in air and water and tested by a plane bending fatigue test. The surface residual stress of the FSWed part was also evaluated by an X-ray diffraction method. It was concluded that the fatigue life and strength of FSWed specimen were improved by cavitation peening. Whereas the fatigue life at σa = 150 MPa of FSWed specimen was about 1/20 of the bulk sheet, cavitation peening was able to extend the fatigue life of the non-peened FSW specimen by 3.6 times by introducing compressive residual stress into the FSWed part. This is the first paper to demonstrate the improvement of fatigue properties of FSWed metallic sheet by cavitation peening.
Effect of Alloying on the Nucleation and Growth of Laves Phase in the 9–10%Cr-3%Co Martensitic Steels during Creep
Authors: Fedoseeva Alexandra , Nikitin Ivan , Tkachev Evgeniy , Mishnev Roman , Dudova Nadezhda , Kaibyshev Rustam
Published: December 2020

Five Co-modified P92-type steels with different contents of Cr, W, Mo, B, N, and Re have been examined to evaluate the effect of the chemical composition on the evolution of Laves phase during creep at 650 °C. The creep tests have been carried out at 650 °C under various applied initial stresses ranging from 80 to 200 MPa until rupture. An increase in the B and Cr contents leads to a decrease in the size and volume fraction of M23C6 carbides precipitated during tempering and an increase in their number particle density along the boundaries. In turns, this affects the amount of the nucleation sites for Laves phase during creep. The (W+Mo) content determines the diffusion growth and coarsening of Laves phase during creep. Susceptibility of Laves phase to coarsening with a high rate is caused by the large difference in Gibbs energy between fine and large particles located at the low-angle and high-angle boundaries, respectively, and can cause the creep strength breakdown. The addition of Re to the 10%Cr steel with low N and high B contents provides the slowest coarsening of Laves phase among the steels studied.
Recrystallization Behavior of a Pure Cu Connection Interface with Ultrasonic Welding
Authors: Su Zhanzhan , Zhu Zhengqiang , Zhang Yifu , Zhang Hua , Xiao Qiankun
Published: December 2020

Three-dimensional metal waveguide components are key components in the next generation of radio telescopes. Ultrasonic additive manufacturing technology combining ultrasonic welding and micro electrical discharge machining (micro-EDM) provides a new method for the overall manufacturing of waveguide elements, and the effective welding of Electrolytic Tough Pitch copper (Cu-ETP) sheets is the key process of this method. This study demonstrates that the orthogonal test optimization method is used to conduct ultrasonic welding tests on Cu-ETP. Specifically, electron backscattered diffraction (EBSD) technology is used to analyze the crystal grains, grain boundary types and texture changes during interface recrystallization. In addition, the finite element software ABAQUS 6.13 is employed to calculate the temperature field in order to determine the possibility of recrystallization of the welding interface. The results showed that the average grain size of the welding interface decreased from 20 to 1~2 μm. The Cu-ETP matrix is mainly composed of coarse grains with high-angle grain boundaries (HAGBs), while a large number of low-angle grain boundaries (LAGBs), subcrystals and fine equiaxed grains appear in the welded joint. At the same time, discontinuous dynamic recrystallization (DDRX) occurs in the less strained area, and continuous dynamic recrystallization (CDRX) is predominant in the greater strain area. The temperature field calculation shows that the peak temperature of the welding interface exceeds the recrystallization temperature of Cu-ETP from 379.05 to 433.2 °C.
Mechanical Characterization of Graphene Nanoplatelets-Reinforced Mg-3Sn Alloy Synthesized by Powder Metallurgy
Authors: Kumar Pravir , Skotnicova Katerina , Mallick Ashis , Gupta Manoj , Cegan Tomas , Jurica Jan
Published: December 2020

The present study investigated the effects of alloying and nano-reinforcement on the mechanical properties (microhardness, tensile strength, and compressive strength) of Mg-based alloys and composites. Pure Mg, Mg-3Sn alloy, and Mg-3Sn + 0.2 GNP alloy-nanocomposite were synthesized by powder metallurgy followed by hot extrusion. The microstructural characteristics of the bulk extruded samples were explored using X-ray diffraction, field-emission scanning electron microscopy, and optical microscopy and their mechanical properties were compared. The microhardness, tensile strength, and compressive strength of the Mg-3Sn alloy improved when compared to those of monolithic Mg sample and further improvements were displayed by Mg-3Sn + 0.2 GNP alloy-nanocomposite. No significant change in the compressive strain to failure was observed in both the alloy and the alloy-nanocomposite with respect to that of the pure Mg sample. However, an enhanced tensile strain to failure was displayed by both the alloy and the alloy-nanocomposite.
Microstructure Evolution in Cu–0.5 wt% Zr Alloy Processed by a Novel Severe Plastic Deformation Technique of Rotational Constrained Bending
Authors: Krajňák Tomáš , Janeček Miloš , Minárik Peter , Gubicza Jenő , Hung Pham Tran , Nový František , Raab Arseniy , Raab Georgy , Asfandiyarov Rashid
Published: December 2020

In the present study, a coarse-grained Cu–0.5 wt% Zr alloy was repeatedly processed by a novel technique of rotational constrained bending (RCB). In this technique, the workpiece was deformed by bending in a channel with an angle of 90°, using a rotating roller. The influence of the number of passes (N) of RCB on strain distribution, microstructure evolution and mechanical properties of the alloy was investigated. The heterogeneous distribution of the microhardness in the billet cross-section after the first pass was transformed into a homogeneous one after twelve passes, due to the rotation of the sample by 90° clockwise between individual passes. In addition, the gradual refinement/homogenization of the microstructure and formation of strong (110) crystallographic texture were found with increasing N. The initial grain size of 180 μm decreased down to 3.4 μm after twelve passes. The dislocation density increased by two orders of magnitude after RCB processing. In accordance with the grain-size refinement and the strong increase of the dislocation density, RCB processing significantly enhanced the strength of the alloy, while the ductility considerably decreased. The yield stress increased from 63 to 524 MPa, while the elongation to failure decreased below 10% after twelve passes.
Urinary Volatile Organic Compound Analysis for the Diagnosis of Cancer: A Systematic Literature Review and Quality Assessment
Authors: Wen Qing , Boshier Piers , Myridakis Antonis , Belluomo Ilaria , Hanna George B.
Published: December 2020

The analysis of urinary volatile organic compounds (VOCs) is a promising field of research with the potential to discover new biomarkers for cancer early detection. This systematic review aims to summarise the published literature concerning cancer-associated urinary VOCs. A systematic online literature search was conducted to identify studies reporting urinary VOC biomarkers of cancers in accordance with the recommendations of the Cochrane Library and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Thirteen studies comprising 1266 participants in total were included in the review. Studies reported urinary VOC profiles of five cancer subtypes: prostate cancer, gastrointestinal cancer, leukaemia/lymphoma, lung cancer, and bladder cancer. Forty-eight urinary VOCs belonging to eleven chemical classes were identified with high diagnostic performance. VOC profiles were distinctive for each cancer type with limited cross-over. The metabolic analysis suggested distinctive phenotypes for prostate and gastrointestinal cancers. The heterogenicity of study design, methodological and reporting quality may have contributed to inconsistencies between studies. Urinary VOC analysis has shown promising performance for non-invasive diagnosis of cancer. However, limitations in study design have resulted in inconsistencies between studies. These limitations are summarised and discussed in order to support future studies.
Investigation of Shear-Driven and Pressure-Driven Liquid Crystal Flow at Microscale: A Quantitative Approach for the Flow Measurement
Authors: Zhu Jianqin , Tang Runze , Chen Yu , Yin Shuai , Huang Yi , Wong Teckneng
Published: December 2020

The liquid crystal-based method is a new technology developed for flow visualizations and measurements at microscale with great potentials. It is the priority to study the flow characteristics before implementation of such a technology. A numerical analysis has been applied to solve the simplified dimensionless two-dimensional Leslie–Ericksen liquid crystal dynamic equation. This allows us to analyze the coupling effect of the LC’s director orientation and flow field. We will be discussing two classic shear flow cases at microscale, namely Couette and Poiseuille flow. In both cases, the plate drag speed in the state of Couette flow are varied as well as the pressure gradients in Poiseuille flow state are changed to study their effects on the flow field distributions. In Poiseuille flow, with the increase of applied pressure gradient, the influence of backflow significantly affects the flow field. Results show that the proposed method has great advantages on measurement near the wall boundaries which could complement to the current adopted flow measurement technique. The mathematical model proposed in this article could be of great potentials in the development of the quantitatively flow measurement technology.
Cell Sorting Using Electrokinetic Deterministic Lateral Displacement
Authors: Ho Bao , Beech Jason , Tegenfeldt Jonas
Published: December 2020

We show that by combining deterministic lateral displacement (DLD) with electrokinetics, it is possible to sort cells based on differences in their membrane and/or internal structures. Using heat to deactivate cells, which change their viability and structure, we then demonstrate sorting of a mixture of viable and non-viable cells for two different cell types. For Escherichia coli, the size change due to deactivation is insufficient to allow size-based DLD separation. Our method instead leverages the considerable change in zeta potential to achieve separation at low frequency. Conversely, for Saccharomyces cerevisiae (Baker’s yeast) the heat treatment does not result in any significant change of zeta potential. Instead, we perform the sorting at higher frequency and utilize what we believe is a change in dielectrophoretic mobility for the separation. We expect our work to form a basis for the development of simple, low-cost, continuous label-free methods that can separate cells and bioparticles based on their intrinsic properties.
Development and Evaluation of an Adaptive Multi-DOF Finger with Mechanical-Sensor Integrated for Prosthetic Hand
Authors: Wu Changcheng , Song Tianci , Wu Zilong , Cao Qingqing , Fei Fei , Yang Dehua , Xu Baoguo , Song Aiguo
Published: December 2020

To realize the adaptive grasping of objects with diverse shapes and to capture the joint angles of the finger, a multi degree of freedom (DOF) adaptive finger for prosthetic hand is proposed in this paper. The fingers are designed with three joints. The maximum rotation angle of the finger joints is 90°. The angle at which the finger joints bend can be captured. Firstly, the prototype design, forward kinematics and force analysis of phalanges are described in detail. In order to achieve an adaptive motion pattern similar to that of the human hand, this paper investigates the optimization of the torsion spring stiffness coefficient so that the metacarpophalangeal (MCP) joints, proximal interphalangeal (PIP) joints, and distal interphalangeal (DIP) joints of the bionic finger meet a motion ratio of approximately 3:3:1. Then, in order to realize the joint angle measurement in the process of grasping an object, the mechanical-sensor integrated finger joint is designed, and the composition, angle measurement principle and measurement circuit are introduced in detail. Finally, joint angle measurement, movement law evaluation and object grasping experiments are performed to verify the validity of the designed finger. The experimental results show that the root-mean-square (RMS) of the DIP, PIP and MCP angle measurement errors are 0.36°, 0.59° and 0.32°, respectively. The designed finger is able to grasp objects with different shapes stably.
Wireless Passive LC Temperature and Strain Dual-Parameter Sensor
Authors: Wang Ya , Tan Qiulin , Zhang Lei , Lin Baimao , Li Meipu , Fan Zhihong
Published: December 2020

There is an increasing demand for bearing temperature and strain monitoring in high-speed rotating systems. This study proposes a new multiresonance, multiplexing, wireless, passive inductance capacitance (LC) temperature and strain sensor. The sensor has two capacitors connected at different locations (turns) on the same inductor to achieve simultaneous temperature and strain measurements. The plate capacitor is connected to the inner part of the inductor and the other interdigital capacitor is connected to the outer part of the inductor to form two LC loops. The structure of the sensor is optimized through High Frequency Structure Simulator (HFSS) simulations to realize frequency separation of the two parameters and avoid mutual interference between the two signals. The sensor is fabricated on a polyimide film using electroplating technology. The experimental results show that the temperature–strain sensor can operate stably from 25 °C to 85 °C with an average sensitivity of 27.3 kHz/°C within this temperature range. The sensor can detect strains in the range of 1000–5000 με with a strain sensitivity of 100 Hz/με at 25 °C. Therefore, the proposed wireless passive LC temperature-strain sensor exhibits stable performance. In addition, the use of a single inductor effectively reduces the sensor’s area. The flexible substrate provides advantageous surface conformal attachment characteristics suitable for monitoring high-temperature rotating parts in adverse environments.
Morphology, Mineralogy, and Chemistry of Ocherous Precipitate Aggregates Downstream of an Abandoned Mine Site
Authors: Manaka Mitsuo
Published: December 2020

Mineral precipitates forming downstream of abandoned and/or uncontrolled mine sites generally act as scavengers for heavy metals, such as As and Sb, leaking from the sites. This study reports the morphology of ocherous precipitate aggregates downstream of Ayuta, an abandoned antimony mine site in Tochigi Prefecture, Japan, because its morphology differs significantly from those reported previously. The morphology of this aggregate consists of stacked, small terraces enclosed by numerous connected rimstone dams, although on a smaller scale compared to typical terrace landscapes. The rimstone pools contained ocherous spheroids precipitates at the bottom. Additionally, stream water and ocherous aggregates collected from the site were investigated for mineralogy and chemistry. As (0.07–0.17 μg/L) and Sb (0.02 μg/L) levels in the stream water were determined, and the distributions of As and Sb in the mineral phases of the precipitate were estimated using a sequential extraction procedure. The investigations revealed that As was adsorbed by iron-bearing ocherous precipitate aggregates, especially ferrihydrite that formed on the stream bank at concentrations, comparable to those reported by other studies (85 mg/kg). This adsorption contributed to the natural attenuation of As in the stream. Sb in the aggregate consisted of ultra-fine silt and clay-size particles of stibnite ore transported from the surrounding area and/or secondary minerals transported by groundwater and surface water.
Carbon Xerogel Nanostructures with Integrated Bi and Fe Components for Hydrogen Peroxide and Heavy Metal Detection
Authors: Fort Carmen I. , Rusu Mihai M. , Cotet Liviu C. , Vulpoi Adriana , Florea Ileana , Tuseau-Nenez Sandrine , Baia Monica , Baibarac Mihaela , Baia Lucian
Published: December 2020

Multifunctional Bi- and Fe-modified carbon xerogel composites (CXBiFe), with different Fe concentrations, were obtained by a resorcinol–formaldehyde sol–gel method, followed by drying in ambient conditions and pyrolysis treatment. The morphological and structural characterization performed by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption/desorption porosimetry, scanning electron microscopy (SEM) and scanning/transmission electron microscopy (STEM) analyses, indicates the formation of carbon-based nanocomposites with integrated Bi and Fe oxide nanoparticles. At higher Fe concentrations, Bi-Fe-O interactions lead to the formation of hybrid nanostructures and off-stoichiometric Bi2Fe4O9 mullite-like structures together with an excess of iron oxide nanoparticles. To examine the effect of the Fe content on the electrochemical performance of the CXBiFe composites, the obtained powders were initially dispersed in a chitosan solution and applied on the surface of glassy carbon electrodes. Then, the multifunctional character of the CXBiFe systems is assessed by involving the obtained modified electrodes for the detection of different analytes, such as biomarkers (hydrogen peroxide) and heavy metal ions (i.e., Pb2+). The achieved results indicate a drop in the detection limit for H2O2 as Fe content increases. Even though the current results suggest that the surface modifications of the Bi phase with Fe and O impurities lower Pb2+ detection efficiencies, Pb2+ sensing well below the admitted concentrations for drinkable water is also noticed.