bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Pico-eNB Tx Power and the Effects of Picocell Range Expansion in Multiband HetNet
Authors: Yasaka Takumi , Yoda Kentaro , Otsuka Hiroyuki
Published: June 2022

The use of heterogeneous networks (HetNets) that combine macrocells and picocells in the same coverage is effective in increasing system capacity and improving user throughput. The use of high carrier frequency bands is also expected to help achieving higher data rates because it promises vast amounts of signal bandwidth. Therefore, multiband HetNets with picocells operating at high carrier frequency bands have attracted significant attention with the aim of increasing system capacity and achieving a high user throughput in fifth-generation mobile systems and beyond. In HetNet deployments, a picocell range expansion (CRE) technique that virtually expands the picocell coverage is well known to allow more user equipment (UE) to access the picocell providing a fixed cell selection offset (CSO) for all UE. Thus far, there has not been sufficient research on optimizing the transmission (Tx) power of pico-evolved node Bs (eNBs) operating at high carrier frequency bands in multiband HetNets. In addition, the effects of CRE in multiband HetNets have not been clarified. In this paper, we first investigated the optimal Tx power of pico-eNB in a multiband HetNet combining macrocells operating at 2 GHz and picocells operating at 4.5 GHz band with a wider signal bandwidth using system-level computer simulations. Then, from the user throughput perspective, we investigated the effects of CRE providing a positive CSO for UE using two pico-eNB Tx powers close to the optimal value. Using these results, we discussed how to choose the pico-eNB Tx power when CRE was activated and validated the design method for a multiband HetNet.
Human-Nature Interactions during and after the COVID-19 Pandemic in Moscow, Russia: Exploring the Role of Contact with Nature and Main Lessons from the City Responses
Authors: Dushkova Diana , Ignatieva Maria , Konstantinova Anastasia , Vasenev Viacheslav , Dovletyarova Elvira , Dvornikov Yury
Published: June 2022

Urban green spaces (UGS) as essential elements of the urban environment provide multiple ecosystem services including benefits for physical and mental health. Impacts of the COVID-19 pandemic and related restrictions have influenced human relationships with nature. Based on empirical research, this article explores the pathways and implications of human-nature interactions during and after COVID-19 and how human health and well-being could be supported by contact with nature. The article discusses the reasons that attract people to visit UGS (value of UGS, their perceptions, ways of contact with urban nature, etc.). It also analyses the effects of social isolation on the usage and perception of UGS during and after the COVID-19 pandemic. The research revealed current needs for UGS and their role in adaptation of urban development and greening strategy. For this purpose, an online questionnaire survey among residents of Moscow was conducted in April–July of 2020 when restrictive measures were imposed in the city in response to the COVID-19 pandemic. Additionally, non-participatory observations and photo documentation were used to supplement the data on UGS visitation and use. The GIS mapping method was applied to analyze the UGS provision (availability and accessibility of UGS). Moreover, expert interviews were conducted aiming to explore the implications of the COVID-19 pandemic on the urban fabric and life of the citizens. The aim was to reveal the main tendencies that can be used in the adaptation of urban development plans, especially regarding UGS and human-nature interactions. The results show that citizens (both survey respondents and experts) highly value urban nature as a tool for coping with COVID-19 challenges. They underlined a need for accessible UGS, most notably for breathing fresh air, reducing stress, relaxing, and observing and enjoying nature. The survey also revealed the particular health effects resulting from the reduction of UGS visitations due to COVID-19 restrictions. Several changes in human-nature interactions were also observed: many respondents especially missed spending time outdoors and meeting other people. That highlights the fact that while UGS normally provides places for social integration and socializing, during the COVID-19 isolation UGS were especially valued in regard to physical health and well-being (self-recovery). Both respondents and experts expressed their opinions regarding the future development of UGS network and how the UGS’s structure and design should be adapted to the current challenges. The claimed interests/preferences included the need for providing all residents equal access to UGS in a time of pandemics and post pandemics. A set of limitations and directions for future research of UGS was suggested.
The Rhenish Coal-Mining Area—Assessing the Transformational Talents and Challenges of a Region in Fundamental Structural Change
Authors: Greiving Stefan , Gruehn Dietwald , Reicher Christa
Published: June 2022

This paper addresses the extensive structural changes of the Rhenish coal-mining area in Germany. Coal mining was and still is a relevant economic activity throughout Europe and is the focus of many political and societal debates, as well as research activities in the Rhenish coal-mining area. The project DAZWISCHEN followed the concept of evidence-based planning and therefore identified, by means of a GIS-based analysis, the structural changes within the Rhenish coal-mining area for the conflicting thematic clusters for settlement development and open space. Moreover, we investigated the complex multi-level governance that the region is characterized by. The results suggest an increased pressure on blue and green infrastructure by new urban development, especially in the northern part of the Rhenish coal-mining area. On the other hand, the southern part of the Rhenish coal-mining area will be more likely to undergo a process towards an increase in green infrastructure. Thus, the future development of the whole area is segregated in two different development trends in the north and south parts. The complex governance structure in the Rhenish coal-mining area requires an in-depth view of the ongoing working processes in the development of ideas and visions for regional mission statements of different planning areas, levels, and network partners in a real-life laboratory.
Friction and Wear Characteristics of Aqueous ZrO2/GO Hybrid Nanolubricants
Authors: Huang Shuiquan , Wang Zhen , Xu Longhua , Huang Chuanzhen
Published: June 2022

Aqueous nanolubricants containing ZrO2 nanoparticles, graphene oxide (GO) nanosheets, or hybrid nanoparticles of ZrO2 and GO were formulated using a cost-effective ultrasonication de-agglomeration method. The friction and wear characteristics of these water-based nanolubricants were systematically investigated using a block-on-ring testing configuration with a stainless- and alloy steel contact pair. The concentrations and mass ratios of nanoadditives were varied from 0.02 to 0.10 wt.% and 1:5 to 5:1, respectively, to obtain optimal lubrication performance. The application of a 0.06 wt.% 1:1 ZrO2/GO hybrid nanolubricant resulted in a 57% reduction in COF and a 77% decrease in wear volume compared to water. The optimised ZrO2/GO hybrid nanolubricant was found to perform better than pure ZrO2 and GO nanolubricant in terms of tribological performance due to its synergistic lubrication effect, which showed up to 54% and 41% reductions in friction as well as 42% and 20% decreases in wear compared with 0.06 wt.% ZrO2 and 0.06 wt.% GO nanolubricants. The analysis of wear scars revealed that using such a ZrO2/GO hybrid nanolubricant yielded a smooth worn surface, with 87%, 45%, and 33% reductions in Sa compared to water and 0.06 wt.% ZrO2 and 0.06 wt.% GO nanolubricants. The superior tribological performance can be ascribed to the combination of the rolling effect of ZrO2 nanoparticles and the slipping effect of GO nanosheets.
Practical Example of Modification of a Gearbox Lubrication System
Authors: Maláková Silvia , Sivák Samuel
Published: June 2022

This paper presents the optimization of the lubrication method of a helical bevel gearbox, which is part of a pickling line. The first gear stage of this gearbox showed frequent failures. The bevel gearing and bearings were damaged. Damage analysis was performed, based on which a change in bevel gearing and bearing lubrication was proposed. In this case, the original transmission was lubricated by dip lubrication. The bevel gear wheel was insufficiently submerged below the lubricating oil level. Due to insufficient lubrication of the bevel gearing, both gear wheels, the bevel pinion, and the bevel wheel were damaged. Central circulating lubrication has been proposed for the bevel gear pair and first gearbox shaft bearings. This paper deals with the design of circulating lubrication components. Changes and modifications to an existing lubrication system are proposed. The layout of the gearbox in question was not originally designed and adapted for the circulating lubrication required. To improve the original lubrication system, it was decided that it should be redesigned with central circulating lubrication, which meant implementing the necessary gearbox casing modifications. Our novel contribution is the proposition of an innovative transmission lubrication system aimed at increasing the service life parameters of the transmission. After the implementation of the proposed modifications to the lubrication method, a period of monitoring the operating characteristics of the gearbox followed. With the modification of the lubrication system of the bevel gear pair, the temperature on the gearing surface was lowered by 39%. The service life of the gearbox increased from the original 1.9 years to at least 5 years. On the basis of the long-term monitoring of changes caused by the adjustment of the lubrication method, we can state that the requirement was met, and the frequent failures of this gearbox were eliminated.
(E)-3-[4-(1H-Imidazol-1-yl)phenyl]-1-(3-chloro-4-fluorophenyl)prop-2-en-1-one
Authors: Takaki Reina , Ashburn Bradley O.
Published: June 2022

Imidazole-containing chalcones have been shown to be effective against Aspergillus fumigatus, the pathogenic agent for pulmonary aspergillosis. Claisen-Schmidt condensation of 4-(1H-imidazol-1-yl)benzaldehyde with 3′-chloro-4′-fluoroacetophenone using aqueous sodium hydroxide in methanol yielded the novel compound (E)-3-[4-(1H-imidazol-1-yl)phenyl]-1-(3-chloro-4-fluorophenyl)prop-2-en-1-one in good purity after purification by silica gel column chromatography. This novel compound is suitable for testing the antifungal properties of the combined pharmacophores against Aspergillus and other pathogenic fungi.
N-(2-Benzoyl-4,5-dimethoxyphenethyl)-2-phenylacetamide
Authors: Marinova Petja , Nikolova Stoyanka , Dołęga Anna , Ahmedova Anife
Published: June 2022

The crystal structure of N-(2-benzoyl-4,5-dimethoxyphenethyl)-2-phenylacetamide indicates that the compound crystallizes in the monoclinic C2/c space group with eight molecules in the unit cell. The heteroatoms from the amide group form a chain of intermolecular N-H ··· O hydrogen bonds propagating along the b axis. The carbonyl group from the benzoyl substituent participates in short contacts with two H-atoms from the ethyl or phenyl groups.
An Investigation of the Ground Walnut Shells’ Addition Effect on the Properties of the Fly Ash-Based Geopolymer
Authors: Kozub Barbara , Castro-Gomes João
Published: June 2022

The development of geopolymers is in line with the requirements of sustainable development. Creating a new type of material from various industrial and bio-based wastes and by-products can lead to reduced energy consumption, reduced waste generation, reduced global CO2 emissions, as well as reduced resource extraction of natural resources. In this study, geopolymer composites based on class F fly ash with the addition of fine quartz sand and ground walnut shells used as a substitute for sand were examined. The study focused on investigating the effects of different weight percentages of ground walnut shells and quartz sand on the density and strength properties, including compressive and flexural strength, thermal conductivity, efflorescence formation, and water absorption of the fly ash-based geopolymer composites. The microstructure of the studied geopolymers was also analyzed using a scanning electron microscope (SEM). It was observed that the addition of ground walnut shells contributes to the decrease in density and mechanical properties, increase in absorption properties, and decrease in porosity of fly ash-based geopolymers. Furthermore, the addition of ground walnut shells allows for a significant reduction in efflorescence on the surface of the tested geopolymer composites. Moreover, partial or complete replacement of sand by ground walnut shells in geopolymer composites based on fly ash allows for a significant reduction in their thermal conductivity, which makes it possible to use these composites as insulation materials.
Investigation of the Structure and Corrosion Resistance of Novel High-Entropy Alloys for Potential Biomedical Applications
Authors: Tokarewicz Marzena , Grądzka-Dahlke Małgorzata , Rećko Katarzyna , Łępicka Magdalena , Czajkowska Kamila
Published: June 2022

High-entropy alloys are a new generation of materials that have attracted the interest of numerous scientists because of their unusual properties. It seems interesting to use these alloys in biomedical applications. However, for this purpose, the basic condition of corrosion resistance must be fulfilled. In this article, selected corrosion properties of self-composed high-entropy alloys are investigated and compared with conventional biomedical alloys, that is titanium alloys and stainless steels. Corrosive parameters were determined using the potentiodynamic method. X-ray diffraction studies were performed to characterize the crystal structures. Microstructures of the prepared materials were examined using a scanning electron microscope, and surface hardness was measured by the Vickers method. The results show that investigated high-entropy alloys are characterized by simple structures. Three out of four tested high-entropy alloys had better corrosion properties than conventional implant alloys used in medicine. The Al0.7CoCrFeNi alloy was characterized by a corrosion potential of −224 mV and a corrosion current density of 0.9 μA/cm2; CoCrFeNiCu by −210 mV and 1.1 μA/cm2; TiAlFeCoNi by −435 mV and 4.6 μA/cm2; and Mn0.5TiCuAlCr by −253 mV and 1.3 μA/cm2, respectively. Therefore, the proposed high-entropy alloys can be considered as potential materials for biomedical applications, but this requires more studies to confirm their biocompatibility.
Micropowder Ca2YMgScSi3O12:Ce Silicate Garnet as an Efficient Light Converter for White LEDs
Authors: Shakhno Anna , Markovskyi Anton , Zorenko Tetiana , Witkiewicz-Łukaszek Sandra , Vlasyuk Yevheniya , Osvet Andres , Elia Jack , Brabec Christoph J. , Batentschuk Miroslaw , Zorenko Yuriy
Published: June 2022

This work is dedicated to the crystallization and luminescent properties of a prospective Ca2YMgScSi3O12:Ce (CYMSSG:Ce) micropowder (MP) phosphor converter (pc) for a white light–emitting LED (WLED). The set of MP samples was obtained by conventional solid-phase synthesis using different amounts of B2O3 flux in the 1–5 mole percentage range. The luminescent properties of the CYMSSG:Ce MPs were investigated at different Ce3+ concentrations in the 1–5 atomic percentage range. The formation of several Ce3+ multicenters in the CYMSSG:Ce MPs was detected in the emission and excitation spectra as well as the decay kinetics of the Ce3+ luminescence. The creation of the Ce3+ multicenters in CYMSSG:Ce garnet results from: (i) the substitution by the Ce3+ ions of the heterovalent Ca2+ and Y3+ cations in the dodecahedral position of the garnet host; (ii) the inhomogeneous local environment of the Ce3+ ions when the octahedral positions of the garnet are replaced by heterovalent Mg2+ and Sc3+ cations and the tetrahedral positions are replaced by Si4+ cations. The presence of Ce3+ multicenters significantly enhances the Ce3+ emission band in the red range in comparison with conventional YAG:Ce phosphor. Prototypes of the WLEDs were also created in this work by using CYMSSG:Ce MP films as phosphor converters. Furthermore, the dependence of the photoconversion properties on the layer thickness of the CYMSSG:Ce MP was studied as well. The changes in the MP layer thickness enable the tuning of the white light thons from cold white/daylight to neutral white. The obtained results are encouraging and can be useful for the development of a novel generation of pcs for WLEDs.
Effect of Preheating Temperature on Geometry and Mechanical Properties of Laser Cladding-Based Stellite 6/WC Coating
Authors: Wu Teng , Shi Wenqing , Xie Linyi , Gong Meimei , Huang Jiang , Xie Yuping , He Kuanfang
Published: June 2022

The effect of 60Si2Mn substrate preheating on the forming quality and mechanical properties of cobalt-based tungsten carbide composite coating was investigated. Substrate preheating was divided into four classes (room temperature, 150 °C, 250 °C, and 350 °C). The morphology, microstructure, and distribution of elements of the coating were analyzed using a two-color laser handheld 3D scanner, a scanning electron microscope (SEM), and an energy dispersive X-ray spectrometer (EDX), respectively. The hardness and wear properties of the cladding layer were characterized through a microhardness tester and a friction wear experiment. The research results show that the substrate preheating temperature is directly proportional to the height of the composite coating. The solidification characteristics of the Stellite 6/WC cladding layer structure are not obviously changed at substrate preheating temperatures of room temperature, 150 °C, and 250 °C. The solidified structure is even more complex at a substrate preheating temperature of 350 °C. At this moment, the microstructure of the cladding layer is mainly various blocky, petaloid, and flower-like precipitates. The hardness and wear properties of the cladding layer are optimal at a substrate preheating temperature of 350 °C in terms of mechanical properties.
Quasi-Static Compression Response of Carbon Fiber Reinforced 2.5D Woven Composites at Different Loading Directions
Authors: Li Tianyu , Chen Lifeng , Shen Wei , Zhu Lvtao
Published: June 2022

2.5D woven composites have been increasingly used in aerospace and military applications due to their excellent mechanical properties. In this research, 2.5D woven composites were produced, and their compression responses were investigated in different directions by compression experiments. XR-CT (X-ray computed tomography) technology was used to observe the microstructural damage profiles, and to analyze the failure mechanism of the material. The results show that when subjected to compression loads, the maximum load-bearing capacity of the material in the thickness direction was better than the maximum load-bearing capacity in the warp and weft directions. The compressive strength of the material in the warp and weft directions was lower than that in the thickness direction, and compression damage patterns in each direction also differed.
Xenoacremones D–H, Bioactive Tyrosine-decahydrofluorene Analogues from the Plant-Derived Fungus Xenoacremonium sinensis
Authors: Liu Zhiguo , Liu Li , Wang Anqi , Li Li , Zhao Sinan , Wang Yanan , Sun Yi
Published: June 2022

Five novel tyrosine-decahydrofluorene analogues, xenoacremones D–H (1–5), each bearing a fused 6/5/6 tricarbocyclic core and a 13-membered para-cyclophane ring system, were isolated from the endophytic fungus Xenoacremonium sinensis. Compound 1 was a novel polyketide synthase–nonribosomal peptide synthetase (PKS–NRPS) tyrosine-decahydrofluorene hybrid containing a 6/5/6/6/5 ring system. Their structures were elucidated from comprehensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. All compounds were evaluated for their inhibitory activities on LPS-induced NO production in macrophages and their cytotoxicities against the NB4 and U937 cell lines. Compounds 3 and 5 exhibited potent anti-inflammatory activities in vitro. Compounds 1 and 3–5 displayed significant antiproliferative activity against the tumor cell lines (IC50 < 20 µM).
Morphology Effect of Zinc Oxide Nanoparticles on the Gas Separation Performance of Polyurethane Mixed Matrix Membranes for CO2 Recovery from CH4, O2, and N2
Authors: Sazanova Tatyana Sergeevna , Smorodin Kirill Alexandrovich , Zarubin Dmitriy Mikhailovich , Otvagina Kseniia Vladimirovna , Maslov Alexey Andreevich , Markov Artem Nikolaevich , Fukina Diana Georgievna , Mochalova Alla Evgenievna , Mochalov Leonid Alexandrovich , Atlaskin Artem Anatolevich , Vorotyntsev Andrey Vladimirovich
Published: June 2022

The effect of the morphology and content of zinc oxide nanoparticles (ZnO-NPs) on the physicochemical, mechanical, and gas transport properties of the polyurethane (PU) mixed matrix membranes (MMMs) with respect to CO2 recovery from CH4, O2, and N2 was studied. The MMMs based on PU with spherical and rod-shaped ZnO-NPs at various loadings, namely, 0.05, 0.1, 0.5, 1, and 2 wt. %, were prepared with membrane density control and studied using AFM, wettability measurements, surface free energy calculation, gas separation and mechanical testing. To evaluate the resistance of the ZnO-NPs to agglomeration in the polymer solutions, zeta potential was determined. The ZnO-NPs with average cross sectional size of 30 nm were obtained by plasma-enhanced chemical vapor deposition (PECVD) from elemental high-purity zinc in a zinc-oxygen-hydrogen plasma-forming gas mixture. It was established that the spherical ZnO-NPs are promising to improve the gas performance of PU-based MMMs for CO2 recovery from natural gas, while the rod-shaped NPs better demonstrate their potential in capturing CO2 in flue gases.
Ionomer Membranes Produced from Hexaarylbenzene-Based Partially Fluorinated Poly(arylene ether) Blends for Proton Exchange Membrane Fuel Cells
Authors: Huang Tzu-Sheng , Wen Hsin-Yi , Chen Yi-Yin , Hung Po-Hao , Hsieh Tung-Li , Huang Wen-Yao , Chang Mei-Ying
Published: June 2022

In this study, a series of high molecular weight ionomers of hexaarylbenzene- and fluorene-based poly(arylene ether)s were synthesized conveniently through condensation and post-sulfonation modification. The use a of blending method might increase the stacking density of chains and affect the formation both of interchain and intrachain proton transfer clusters. Multiscale phase separation caused by the dissolution and compatibility differences of blend ionomer in high-boiling-point solvents was examined through analysis and simulations. The blend membranes produced in this study exhibited a high proton conductivity of 206.4 mS cm−1 at 80 °C (increased from 182.6 mS cm−1 for precursor membranes), excellent thermal resistance (decomposition temperature > 200 °C), and suitable mechanical properties with a tensile strength of 73.8–77.4 MPa. As a proton exchange membrane for fuel cell applications, it exhibits an excellent power efficiency of approximately 1.3 W cm−2. Thus, the ionomer membranes have strong potential for use in proton exchange membrane fuel cells and other electrochemical applications.
Flexible Membranes for Batteries and Supercapacitor Applications
Authors: Glukhova Olga
Published: June 2022

Modern portable electronic devices, roll-up displays and wearable systems for personal multimedia devices require flexible energy storage devices [...]
Microfluidics and MEMS Technology for Membranes
Authors: Casals-Terré Jasmina
Published: June 2022

Nowadays manufacturing processes at nano and microscale provide reliable platform for the development of novel applications, specially in the membrane’s field [...]
The Biological Performance of a Novel Electrokinetic-Assisted Membrane Photobioreactor (EK-MPBR) for Wastewater Treatment
Authors: Amini Maryam , Mohamedelhassan Eltayeb , Liao Baoqiang
Published: June 2022

Developing an effective phycoremediation system, especially by utilizing microalgae, could provide a valuable approach in wastewater treatment for simultaneous nutrient removal and biomass generation, which would help control environmental pollution. This research aims to study the impact of low-voltage direct current (DC) application on Chlorella vulgaris properties and the removal efficiency of nutrients (N and P) in a novel electrokinetic-assisted membrane photobioreactor (EK-MPBR) in treating synthetic municipal wastewater. Two membrane photobioreactors ran in parallel for 49 days with and without an applied electric field (current density: 0.261 A/m2). Mixed liquid suspended soils (MLSS) concentration, chemical oxygen demand (COD), floc morphology, total phosphorus (TP), and total nitrogen (TN) removals were measured during the experiments. The results showed that EK-MPBR achieved biomass production comparable to the control MPBR. In EK-MPBR, an over 97% reduction in phosphate concentration was achieved compared to 41% removal in the control MPBR. The control MPBR outperformed the nitrogen removal of EK-MPBR (68% compared to 43% removal). Induced DC electric field led to lower pH, lower zeta potential, and smaller particle sizes in the EK-MPBR as compared with MPBR. The results of this novel study investigating the incorporation of Chlorella vulgar is in an electrokinetic-assisted membrane photobioreactor indicate that this is a promising technology for wastewater treatment.
Ultra-Low-Pressure Membrane Filtration for Simultaneous Recovery of Detergent and Water from Laundry Wastewater
Authors: Khery Yusran , Daniar Sonia Ely , Mat Nawi Normi Izati , Bilad Muhammad Roil , Wibisono Yusuf , Nufida Baiq Asma , Ahmadi Ahmadi , Jaafar Juhana , Huda Nurul , Kobun Rovina
Published: June 2022

Reusing water and excess detergent from the laundry industry has become an attractive method to combat water shortages. Membrane filtration is considered an advanced technique and highly attractive due to its excellent advantages. However, the conventional membrane filtration method suffers from membrane fouling, which restricts its performance and diminishes its economic viability. This study assesses the preliminary performance of submerged, gravity-driven membrane filtration—under ultra-low trans-membrane pressure (△P) of <0.1 bar—to combat membrane fouling issues for detergent and water recovery from laundry wastewater. The results show that even under ultra-low pressure, the membrane suffered from compaction that lowered its permeability by 14% under △P of 6 and 10 kPa, with corresponding permeabilities of 2085 ± 259 and 1791 ± 42 L/(m2 h bar). Filtration of a detergent solution also led to up to 8% permeability loss due to membrane fouling. During the filtration of laundry wastewater, 80–91% permeability loss was observed, leading to the lowest flux of 15.6 L/(m2·h) at △P of 10 kPa, 38% lower than △P of 6 kPa (of 25.2 L/(m2·h)). High △P led to both the membrane and the foulant compaction inflating the filtration resistance. The system could recover 83.6% of excess residual detergent, while most micelles were rejected (ascribed from 71% of COD removal). The TDS content could not be retained, disallowing maximum resource recovery. A gravity-driven filtration system can be self-sustained with minimum supervision in residential and industrial laundries. Nevertheless, a detailed study on long-term filtration performance and multiple cleaning cycles is still required in the future.
Producing Ti5Mo-Fused Tracks and Layers via Laser Powder Bed Fusion
Authors: Dzogbewu Thywill Cephas , Du Preez Willie Bouwer
Published: June 2022

The principal optimum process parameters for printing Ti5Mo fused tracks and layers were determined. The laser power, scanning speed and hatch distance were varied to study their influence on fused track and layer formation. The morphology, geometry, homogeneity, surface roughness, solidification structure, microstructure and microhardness of the fused tracks and layers were analysed. It was observed that, based on the laser energy density, different fused tracks and layers can be achieved. It is only at a certain critical threshold that optimum process parameters could be obtained. Laser power of 200 W with a corresponding scanning speed of 1.0 m/s at a hatch distance of 80 µm was obtained as the optimum process parameter set. As opposed to previous research by the authors, the Mo powder particles in the current investigation melted completely in the Ti5Mo alloy matrix due to the small Mo powder particle size (1 µm). A 50% offset rescanning strategy also improved the surface quality of the layers. The solidification front is predominantly cellular, and the microhardness values obtained fall within the values reported in the current literature.
Energy Metabolism in Mouse Sciatic Nerve A Fibres during Increased Energy Demand
Authors: Rich Laura R. , Ransom Bruce R. , Brown Angus M.
Published: June 2022

The ability of sciatic nerve A fibres to conduct action potentials relies on an adequate supply of energy substrate, usually glucose, to maintain necessary ion gradients. Under our ex vivo experimental conditions, the absence of exogenously applied glucose triggers Schwann cell glycogen metabolism to lactate, which is transported to axons to fuel metabolism, with loss of the compound action potential (CAP) signalling glycogen exhaustion. The CAP failure is accelerated if tissue energy demand is increased by high-frequency stimulation (HFS) or by blocking lactate uptake into axons using cinnemate (CIN). Imposing HFS caused CAP failure in nerves perfused with 10 mM glucose, but increasing glucose to 30 mM fully supported the CAP and promoted glycogen storage. A combination of glucose and lactate supported the CAP more fully than either substrate alone, indicating the nerve is capable of simultaneously metabolising each substrate. CAP loss resulting from exposure to glucose-free artificial cerebrospinal fluid (aCSF) could be fully reversed in the absence of glycogen by addition of glucose or lactate when minimally stimulated, but imposing HFS resulted in only partial CAP recovery. The delayed onset of CAP recovery coincided with the release of lactate by Schwann cells, suggesting that functional Schwann cells are a prerequisite for CAP recovery.
Changes in the Fatty Acid Composition of Milk of Lipizzaner Mares during the Lactation Period
Authors: Gregić Maja , Mijić Pero , Baban Mirjana , Aladrović Jasna , Pađen Lana , Gantner Vesna , Bobić Tina
Published: June 2022

The composition and properties of the milk fat of mares’ milk is interesting from a nutritional standpoint. The aim of this study was to determine the nutritional value of Lipizzaner mare’s milk for possible human consumption and identity the influence of the parity and stage of lactation on its fatty acid (FA) composition. This study was conducted on 17 Lipizzaner mares from a state stud farm in the Slavonian region (eastern Croatia). Mares were hand-milked twice during lactation in the fourth and sixth months. Significantly higher contents of MUFAs (monounsaturated fatty acids) and PUFAs (polyunsaturated fatty acids) and lower ratios of n-6/n-3 were found in the fourth month of lactation. This parity significantly affected the PUFA/SFA ratio (polyunsaturated fatty acids/saturated fatty acids), with lower values found in older mares. The fatty acid composition of mare’s milk that is especially high in UFAs (unsaturated fatty acids) is considered to be beneficial for consumers.
New Approaches to Manage Asian Soybean Rust (Phakopsora pachyrhizi) Using Trichoderma spp. or Their Antifungal Secondary Metabolites
Authors: El-Hasan Abbas , Walker Frank , Klaiber Iris , Schöne Jochen , Pfannstiel Jens , Voegele Ralf T.
Published: June 2022

Attempts have been made to determine the in vitro and in planta suppressive potential of particular Trichoderma strains (T16 and T23) and their secondary metabolites (SMs) against Asian soybean rust (ASR) incited by Phakopsora pachyrhizi. Aside from the previously identified SMs 6-pentyl-α-pyrone (6PAP) and viridiofungin A (VFA), the chemical structures of harzianic acid (HA), iso-harzianic acid (iso-HA), and harzianolide (HZL) were characterized in this study. Our results indicate that exposure of urediospores to 200 ppm 6PAP completely inhibits germination. A slightly higher dosage (250 ppm) of HZL and VFA reduces germination by 53.7% and 44%, respectively. Germ tube elongation seems more sensitive to 6PAP than urediospore germination. On detached leaves, application of conidia of T16 and T23 results in 81.4% and 74.3% protection, respectively. Likewise, 200 ppm 6PAP recorded the highest ASR suppression (98%), followed by HZL (78%) and HA (69%). Treatment of undetached leaves with 6PAP, HA, or HZL reduces ASR severity by 84.2%, 65.8%, and 50.4%, respectively. Disease reduction on the next, untreated trifoliate by T23 (53%), T16 (41%), HZL (42%), and 6PAP (32%) suggests a translocation or systemic activity of the SMs and their producers. To our knowledge, this study provides the first proof for controlling ASR using antifungal SMs of Trichoderma. Our findings strongly recommend the integration of these innovative metabolites, particularly 6PAP and/or their producers in ASR management strategies.
Identification of Insulin Resistance Biomarkers in Metabolic Syndrome Detected by UHPLC-ESI-QTOF-MS
Authors: Alsoud Leen Oyoun , Soares Nelson C. , Al-Hroub Hamza M. , Mousa Muath , Kasabri Violet , Bulatova Nailya , Suyagh Maysa , Alzoubi Karem H. , El-Huneidi Waseem , Abu-Irmaileh Bashaer , Bustanji Yasser , Semreen Mohammad H.
Published: June 2022

Metabolic syndrome (MetS) is a disorder characterized by a group of factors that can increase the risk of chronic diseases, including cardiovascular diseases and type 2 diabetes mellitus (T2D). Metabolomics has provided new insight into disease diagnosis and biomarker identification. This cross-sectional investigation used an untargeted metabolomics-based technique to uncover metabolomic alterations and their relationship to pathways in normoglycemic and prediabetic MetS participants to improve disease diagnosis. Plasma samples were collected from drug-naive prediabetic MetS patients (n = 26), normoglycemic MetS patients (n = 30), and healthy (normoglycemic lean) subjects (n = 30) who met the inclusion criteria for the study. The plasma samples were analyzed using highly sensitive ultra-high-performance liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF-MS). One-way ANOVA analysis revealed that 59 metabolites differed significantly among the three groups (p < 0.05). Glutamine, 5-hydroxy-L-tryptophan, L-sorbose, and hippurate were highly associated with MetS. However, 9-methyluric acid, sphinganine, and threonic acid were highly associated with prediabetes/MetS. Metabolic pathway analysis showed that arginine biosynthesis and glutathione metabolism were associated with MetS/prediabetes, while phenylalanine, D-glutamine and D-glutamate, and lysine degradation were highly impacted in MetS. The current study sheds light on the potential diagnostic value of some metabolites in metabolic syndrome and the role of their alteration on some of the metabolic pathways. More studies are needed in larger cohorts in order to verify the implication of the above metabolites on MetS and their diagnostic value.
Reconstruction of the Genome-Scale Metabolic Model of Saccharopolyspora erythraea and Its Application in the Overproduction of Erythromycin
Authors: Xu Feng , Lu Ju , Ke Xiang , Shao Minghao , Huang Mingzhi , Chu Ju
Published: June 2022

Saccharopolyspora erythraea is considered to be an effective host for erythromycin. However, little is known about the regulation in terms of its metabolism. To develop an accurate model-driven strategy for the efficient production of erythromycin, a genome-scale metabolic model (iJL1426) was reconstructed for the industrial strain. The final model included 1426 genes, 1858 reactions, and 1687 metabolites. The accurate rates of the growth predictions for the 27 carbon and 31 nitrogen sources available were 92.6% and 100%, respectively. Moreover, the simulation results were consistent with the physiological observation and 13C metabolic flux analysis obtained from the experimental data. Furthermore, by comparing the single knockout targets with earlier published results, four genes coincided within the range of successful knockouts. Finally, iJL1426 was used to guide the optimal addition strategy of n-propanol during industrial erythromycin fermentation to demonstrate its ability. The experimental results showed that the highest erythromycin titer was 1442.8 μg/mL at an n-propanol supplementation rate of 0.05 g/L/h, which was 45.0% higher than that without n-propanol supplementation, and the erythromycin-specific synthesis rate was also increased by 30.3%. Therefore, iJL1426 will lead to a better understanding of the metabolic capabilities and, thus, is helpful in a systematic metabolic engineering approach.
Fabrication of a New Electrochemical Sensor Based on Bimetal Oxide for the Detection of Furazolidone in Biological Samples
Authors: Sundaresan Ruspika , Mariyappan Vinitha , Chen Shen-Ming , Alagarsamy Saranvignesh , Akilarasan Muthumariappan
Published: June 2022

This study utilized a simple hydrothermal method to synthesize nickel molybdenum oxide (NMO) for the detection of furazolidone (FZE). Our synthesized NMO was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron spectroscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDX). The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to detect the FZE. Under optimized conditions, the obtained results showed that the NMO had an excellent electrocatalytic property towards FZE. As a result, NMO/GCE showed a good linear range of 0.001–1765 µM, an excellent detection limit (LOD) of 0.02 µM, and sensitivity of 0.2042 µA µM−1 cm−2.
Enhanced Performance of La0.8Sr0.2FeO3-δ-Gd0.2Ce0.8O2-δ Cathode for Solid Oxide Fuel Cells by Surface Modification with BaCO3 Nanoparticles
Authors: Desta Halefom G. , Yang Yang , Teketel Birkneh Sirak , Yang Quan , Song Kai , Zhu Shiyue , Tian Dong , Chen Yonghong , Luo Tianyong , Lin Bin
Published: June 2022

Recently, Fe-based perovskite oxides, such as Ln1-xSrxFeO3-δ (Ln = La, Pr, Nd, Sm, Eu) have been proposed as potential alternative electrode materials for solid oxide fuel cells (SOFCs), due to their good phase stability, electrocatalytic activity, and low cost. This work presents the catalytic effect of BaCO3 nanoparticles modified on a cobalt-free La0.8Sr0.2FeO3-δ-Gd0.2Ce0.8O2-δ (LSF-GDC) composite cathode at an intermediate-temperature (IT)-SOFC. An electrochemical conductivity relaxation investigation (ECR) shows that the Kchem value of the modified LSF-GDC improves up to a factor of 17.47, demonstrating that the oxygen reduction process is effectively enhanced after surface impregnation by BaCO3. The area-specific resistance (ASR) of the LSF-GDC cathode, modified with 9.12 wt.% BaCO3, is 0.1 Ω.cm2 at 750 °C, which is about 2.2 times lower than that of the bare cathode (0.22 Ω.cm2). As a result, the anode-supported single cells, with the modified LSF-GDC cathode, deliver a high peak power density of 993 mW/cm2 at 750 °C, about 39.5% higher than that of the bare cell (712 mW/cm2). The single cells based on the modified cathode also displayed good performance stability for about 100 h at 700 °C. This study demonstrates the effectiveness of BaCO3 nanoparticles for improving the performance of IT-SOFC cathode materials.
Study of the Pattern Preparation and Performance of the Resistance Grid of Thin-Film Strain Sensors
Authors: Cheng Yunping , Wu Wenge , Zhao Yongjuan , Han Yanwen , Song Ding
Published: June 2022

The thin-film strain sensor is a cutting-force sensor that can be integrated with cutting tools. The quality of the alloy film strain layer resistance grid plays an important role in the performance of the sensor. In this paper, the two film patterning processes of photolithography magnetron sputtering and photolithography ion beam etching are compared, and the effects of the geometric size of the thin-film resistance grid on the resistance value and resistance strain coefficient of the thin film are compared and analyzed. Through orthogonal experiments of incident angle, argon flow rate, and substrate negative bias in the ion beam etching process parameters, the effects of the process parameters on photoresist stripping quality, etching rate, surface roughness, and resistivity are discussed. The effects of process parameters on etching rate, surface roughness, and resistivity are analyzed by the range method. The effect of substrate temperature on the preparation of Ni Cr alloy films is observed by scanning electron microscope. The surface morphology of the films before and after ion beam etching is observed by atomic force microscope. The influence of the lithography process on the surface quality of the film is discussed, and the etching process parameters are optimized.
Identification of Fungi in Flaxseed (L. usitatissimum L.) Using the ITS1 and ITS2 Intergenic Regions
Authors: Rollemberg Nathalia de Castro , Hassemer Guilherme de Souza , Pierezan Milena Dutra , Maran Bruna Marchesan , Dalla Nora Flávia Michelon , Verruck Silvani
Published: June 2022

Flaxseed (Linum usitatissimum L.) displays functional properties and contains α-linolenic acid (omega-3). It also contains soluble and insoluble fiber, lignans, phenolic acids, flavonoids, phytic acid, vitamins, and minerals. However, its microbiota can cause fungal contaminations, drastically reducing its quality. The objective of this work was to identify the fungi present in bulk flaxseed through the internal transcribed spacer (ITS1) intergenic region using a metataxonomics approach. Fungal identification was performed via high-performance sequencing of the ITS1 region using ITS1 (GAACCWGCGGARGGATCA) and ITS2 (GCTGCGTTCTTCATCGATGC) as primers with 300 cycles and single-end sequencing in the MiSeq Sequencing System equipment (Illumina Inc., San Diego, CA, USA). Six genera and eight species of fungi were found in the sample. The genus Aspergillus stood out with three xerophilic species found, A. cibarius, A. Appendiculatus, and A. amstelodami, the first being the most abundant. The second most abundant genus was Wallemia, with the species W. muriae. This is one of the fungi taxa with great xerophilic potential, and some strains can produce toxins. Metataxonomics has proved to be a complete, fast, and efficient method to identify different fungi. Furthermore, high-performance genetic sequencing is an important ally in research, helping to develop novel technological advances related to food safety.
Characterization and Leaching Kinetics of Rare Earth Elements from Phosphogypsum in Hydrochloric Acid
Authors: Guan Qingjun , Sui Ying , Liu Chufeng , Wang Yongjie , Zeng Chuxiong , Yu Weijian , Gao Zhiyong , Zang Zhenyue , Chi Ru-an
Published: June 2022

The characterization and leaching mechanism of REEs from phosphogypsum (PG) in HCl was studied in-depth. REEs contained in the PG were 208 ppm, of which Y, La, Ce, and Nd were the four most abundant elements. The modes of occurrence of rare earth elements (REEs) in the PG were quantified using the sequential chemical extraction (SCE) method. Among the five REE occurrence species, the metal oxide form accounted for the largest proportion, followed by the residual, organic matter, and ion-exchangeable fractions, and REEs bound to carbonates were the least. From the comparison of the distributions of REEs and calcium in different occurrence states, it can be determined that REEs contained in the PG were mainly present in the residue state (existed in the gypsum lattice) and the metal oxide state (easily leached). The leaching results show that the suitable leaching conditions were acid concentration of 1.65 mol/L, S/L ratio of 1/10, and reaction temperature of 60 °C. At the condition, the maximum leaching efficiency for ∑REE was 65.6%, of which the yttrium leaching rate was the highest and reached 73.8%. Importantly, A new kinetic equation based on the cylindrical shrinking core model (SCM) was deduced and could well describe REE leaching process from PG. The apparent activation energy for ∑REE leaching was determined to be 20.65 kJ·mol−1.
Geochronology and Geochemistry of the Granite Porphyry from the Qinglingou Gold Deposit, South Qinling, China: Implication for Petrogenesis and Mineralization
Authors: Ding Kun , Yang Xiuqing , Wang Hui , Li Ying , Liu Kai , Wang Zhihui , Zhao Liang , Chen Yanjun
Published: June 2022

The Zhashui-Shanyang ore cluster area is one of the most important gold polymetallic ones in northwestern China. The Qinglingou gold deposit is a newly discovered small-scale deposit in the Zhashui-Shanyang area. Gold mineralization closely related to acid intrusive rocks has been found for the first time in this area. In this paper, the geochronology, whole-rock geochemistry, and isotope signature of the granite porphyries in the deposit are studied. They are characterized by variable medium SiO2 (67.22–71.72 wt.%), high K2O + Na2O contents (6.54–10.34 wt.%), and variable Al2O3 (14.47–15.10 wt.%) values. The A/CNK ratios range from 0.90 to 1.23, and the A/NK ratios vary from 1.14 to 1.48. These rocks also contain biotite and amphiboles and are similar to peraluminous and high-K calc-alkaline I-type granites. The Qinglingou granite porphyries show relative enrichment of Rb, Th, and K, and depletion of Nb, Ta, P, Ti, and other high field strength elements. These porphyries are enriched in light rare earth elements relative to heavy rare earth elements with weak negative Eu anomalies (δEu = 0.63–0.89), which is interpreted to be the best age of crystallization of the Qinglingou porphyries. LA–ICPMS zircon U–Pb dating yields an age of 211 ± 1.2 Ma (n = 16, MSWD = 0.39). The close spatial relationship between the ore bodies and granite porphyry dikes indicates that this age may represent the metallogenic age in this area. The zircons have 176Hf/177Hf ratios ranging from 0.282625 to 0.282702, the εHf(t) values are near 0 and the two-stage zircon Hf model ages range from 1121 to 1296 Ma. These data indicate that the Qinglingou granite porphyries were derived from the interplay between mantle- and crustal-derived magmas. We therefore propose that there is potential gold in carbonate rocks at the periphery of porphyry-skarn copper-molybdenum deposits.