bluuebunny/crossref_metadata_2025 huggingface dataset:
Insight into the Interaction between Water and Ion-Exchanged Aluminosilicate Glass by Nanoindentation
Authors: Li Xiaoyu , Jiang Liangbao , Liu Jiaxi , Wang Minbo , Li Jiaming , Yan Yue
Published: May 2021

This work aims to explore the interaction between water and ion-exchanged aluminosilicate glass. The surface mechanical properties of ion-exchanged glasses after different hydration durations are investigated. The compressive stress and depth of stress layer are determined with a surface stress meter on the basis of photo-elasticity theory. The hardness and Young’s modulus are tested through nanoindentation. Infrared spectroscopy is used to determine the variation in surface structures of the glass samples. The results show that hydration has obvious effects on the hardness and Young’s modulus of the raw and ion-exchanged glasses. The hardness and Young’s modulus decrease to different extents after different hydration times, and the Young’s modulus shows some recovery with the prolonging of hydration time. The ion-exchanged glasses are more resistant to hydration. The tin side is more resistant to hydration than the air side. The results are expected to serve as reference for better understanding the hydration process of ion-exchanged glass.
Numerical Modeling of Unreinforced Masonry Walls Strengthened with Fe-Based Shape Memory Alloy Strips
Authors: Rezapour Moein , Ghassemieh Mehdi , Motavalli Masoud , Shahverdi Moslem
Published: May 2021

This study presents a new way to improve masonry wall behavior. Masonry structures comprise a significant part of the world’s structures. These structures are very vulnerable to earthquakes, and their performances need to be improved. One way to enhance the performances of such types of structures is the use of post-tensioning reinforcements. In the current study, the effects of shape memory alloy as post-tensioning reinforcements on originally unreinforced masonry walls were investigated using finite element simulations in Abaqus. The developed models were validated based on experimental results in the literature. Iron-based shape memory alloy strips were installed on masonry walls by three different configurations, namely in cross or vertical forms. Seven macroscopic masonry walls were modeled in Abaqus software and were subjected to cyclic loading protocol. Parameters such as stiffness, strength, durability, and energy dissipation of these models were then compared. According to the results, the Fe-based strips increased the strength, stiffness, and energy dissipation capacity. So that in the vertical-strip walls, the stiffness increases by 98.1%, and in the cross-strip model’s position, the stiffness increases by 127.9%. In the vertical-strip model, the maximum resistance is equal to 108 kN, while in the end cycle, this number is reduced by almost half and reaches 40 kN, in the cross-strip model, the maximum resistance is equal to 104 kN, and in the final cycle, this number decreases by only 13.5% and reaches 90 kN. The scattering of Fe-based strips plays an important role in energy dissipation. Based on the observed behaviors, the greater the scattering, the higher the energy dissipation. The increase was more visible in the walls with the configuration of the crossed Fe-based strips.
A Flexible Two-Sensor System for Temperature and Bending Angle Monitoring
Authors: Mu Yifeng , Feng Rou , Gong Qibei , Liu Yuxuan , Jiang Xijun , Hu Youfan
Published: May 2021

A wearable electronic system constructed with multiple sensors with different functions to obtain multidimensional information is essential for making accurate assessments of a person’s condition, which is especially beneficial for applications in the areas of health monitoring, clinical diagnosis, and therapy. In this work, using polyimide films as substrates and Pt as the constituent material of serpentine structures, flexible temperature and angle sensors were designed that can be attached to the surface of an object or the human body for monitoring purposes. In these sensors, changes in temperature and bending angle are converted into variations in resistance through thermal resistance and strain effects with a sensitivity of 0.00204/°C for temperatures in the range of 25 to 100 °C and a sensitivity of 0.00015/° for bending angles in the range of 0° to 150°. With an appropriate layout design, two sensors were integrated to measure temperature and bending angles simultaneously in order to obtain decoupled, compensated, and more accurate information of temperature and angle. Finally, the system was tested by being attached to the surface of a knee joint, demonstrating its application potential in disease diagnosis, such as in arthritis assessment.
Microstructural and Mechanical Evaluation of a Cr-Mo-V Cold-Work Tool Steel Produced via Electron Beam Melting (EBM)
Authors: Botero Carlos Alberto , Şelte Aydın , Ramsperger Markus , Maistro Giulio , Koptyug Andrey , Bäckström Mikael , Sjöström William , Rännar Lars-Erik
Published: May 2021

In this work, a highly alloyed cold work tool steel, Uddeholm Vanadis 4 Extra, was manufactured via the electron beam melting (EBM) technique. The corresponding material microstructure and carbide precipitation behavior as well as the microstructural changes after heat treatment were characterized, and key mechanical properties were investigated. In the as-built condition, the microstructure consists of a discontinuous network of very fine primary Mo- and V-rich carbides dispersed in an auto-tempered martensite matrix together with ≈15% of retained austenite. Adjusted heat treatment procedures allowed optimizing the microstructure by the elimination of Mo-rich carbides and the precipitation of fine and different sized V-rich carbides, along with a decrease in the retained austenite content below 2%. Hardness response, compressive strength, and abrasive wear properties of the EBM-manufactured material are similar or superior to its as-HIP forged counterparts manufactured using traditional powder metallurgy route. In the material as built by EBM, an impact toughness of 16–17 J was achieved. Hot isostatic pressing (HIP) was applied in order to further increase ductility and to investigate its impact upon the microstructure and properties of the material. After HIPing with optimized protocols, the ductility increased over 20 J.
Effect of Different Lubricating Environment on the Tribological Performance of CNT Filled Glass Reinforced Polymer Composite
Authors: Agrawal Sandeep , Singh Nishant K. , Upadhyay Rajeev Kumar , Singh Gurminder , Singh Yashvir , Singh Sunpreet , Pruncu Catalin I.
Published: May 2021

In recent years, the engineering implications of carbon nanotubes (CNTs) have progressed enormously due to their versatile characteristics. In particular, the role of CNTs in improving the tribological performances of various engineering materials is well documented in the literature. In this work, an investigation has been conducted to study the tribological behaviour of CNTs filled with glass-reinforced polymer (GFRP) composites in dry sliding, oil-lubricated, and gaseous (argon) environments in comparison to unfilled GFRP composites. The tribological study has been conducted on hardened steel surfaces at different loading conditions. Further, the worn surfaces have been examined for a particular rate of wear. Field-emission scanning electron (FESEM) microscopy was used to observe wear behaviours. The results of this study explicitly demonstrate that adding CNTs to GFRP composites increases wear resistance while lowering friction coefficient in all sliding environments. This has also been due to the beneficial strengthening and self-lubrication properties caused by CNTs on GFRP composites, according to FESEM research.
Numerical Study of Heat and Mass Transfer during Cryopreservation Process with Application of Directed Interval Arithmetic
Authors: Piasecka-Belkhayat Alicja , Skorupa Anna
Published: May 2021

In the present paper, numerical modelling of heat and mass transfer proceeding in a two-dimensional axially symmetrical articular cartilage sample subjected to a cryopreservation process is presented. In the model under consideration, interval parameters were assumed. The heat transfer process is described using the Fourier interval equation, while the cryoprotectant transport (DMSO) across the cell membrane is analyzed using a two-parameter model taking into account the simulation of the water volume in the chondrocytes and the change in DMSO concentration over time. The liquidus tracking (LT) protocol introduced by Pegg et al. was used to model the cryopreservation process. This procedure divides the heating and cooling phases into eight and seven steps, respectively, allowing precise regulation of temperature and cryoprotectant (CPA) concentration of bathing solutions. This protocol protects chondrocytes from ice crystal, osmotic stress, and electrolyte damage. The obtained interval concentrations of cryoprotectant in chondrocytes were compared with previous simulations obtained using the deterministic model and they are mostly in agreement with the simulation data.
Lutein Treatment Effects on the Redox Status and Metalloproteinase-9 (MMP-9) in Oral Cancer Squamous Cells—Are There Therapeutical Hopes?
Authors: Enășescu Dan Alexandru , Moisescu Mihaela Georgeta , Imre Marina , Greabu Maria , Ripszky Totan Alexandra , Stanescu-Spinu Iulia , Burcea Marian , Albu Crenguta , Miricescu Daniela
Published: May 2021

Carotenoids loaded in nanoparticles should be regarded as a promising way to increase the availability in healthy cells and to induce apoptosis in cancer. Lutein is a carotenoid that, in contrast to beta-carotene, has no known toxicities. Oral cancer represents one of the most frequent types of cancer world-wide with an incidence rate of about 9% of all types of cancer. Almost 95% of all oral cancers are represented by squamous cell carcinomas (OSCC). The aim of this study was to review and analyse the effects of lutein and Poly(d,l-lactide-co-glycolide) (PLGA) Nps containing lutein (Lut Nps) on oxidative stress biomarkers (OXSR-1, FOXO-3, TAC) and collagen degradation biomarker–MMP-9, in human cells BICR10 of buccal mucosa squamous carcinoma. Lut Nps were prepared by the emulsion-solvent evaporation method. MMP, OXSR-1, TAC, FOXO-3 and MMP-9 were measured in tumour cell lysates by the ELISA technique. Our results have shown that in Lut 100 cells and Lut Nps the OXSR1 (p < 0.001, p < 0.001) and TAC (p < 0.001, p < 0.001) values were significantly higher than in control cells. The Lut 100 and Lut Nps FOXO-3 levels revealed no significant differences versus the control. MMP-9 levels were significantly reduced (p < 0.001) in the Lut Nps cells versus control cells. In our study conditions, lutein and lutein Nps did not trigger an oxidative stress by ROS induction. However, lutein Nps treatment seemed to have a positive effect, by downregulating the MMP-9 levels. Loaded in Nps, lutein could be regarded as a protective factor against local invasiveness, in whose molecular landscape MMPs, and especially MMP-9 are the main actors.
Shape- and Size-Controlled Palladium Nanocrystals and Their Electrocatalytic Properties in the Oxidation of Ethanol
Authors: Lee Seokhee , Cho Hyeongkyu , Kim Hyeon Jeong , Hong Jong Wook , Lee Young Wook
Published: May 2021

Pd nanoparticles (PdNPs) were synthesized in an aqueous environment via the reduction of K2PdCl4 by a surfactant under a high temperature. Highly monodisperse spherical PdNPs and multi-pod PdNPs with a controlled size ranging from 18 to 50 nm were prepared in high yields by varying the concentration of cetyltrimethylammonium chloride. The structural and optical properties of the synthesized Pd NPs were characterized by transmission electron microscopy, X-ray diffraction and UV–vis spectroscopy. The spherical and multi-pod PdNPs exhibited catalytic properties that were unique to their size and shape and presented efficient electrocatalytic activities toward the ethanol oxidation reaction.
Characterization of Glass Powder from Glass Recycling Process Waste and Preliminary Testing
Authors: Gimenez-Carbo Ester , Soriano Lourdes , Roig-Flores Marta , Serna Pedro
Published: May 2021

This work studies the possibility of incorporating different proportions of glass powder from the waste glass (rejected material called fine cullet) produced during the glass recycling process into the manufacturing of mortar and concrete. For this purpose, the material is characterized by its chemical composition and pozzolanic activity, and the shape and size of its particles are studied. It is then incorporated as a substitute for cement into the manufacturing of mortar and concrete at 25% and 40% of cement weight, and its effect on setting times, consistency, and mechanical strength is analyzed. Its behavior as a slow pozzolan is verified, and the possibility of incorporating it into concrete is ratified by reducing its cement content and making it a more sustainable material.
An Experimental Investigation on the Cutting Quality of Three Different Rock Specimens Using High Power Multimode Fiber Laser
Authors: Lian Mang-Muan , Seo Youngjin , Lee Dongkyoung
Published: May 2021

The laser cutting of rock has been popular recently because of its advantages over traditional rock cutting methods. Several types of research were performed to replace traditional rock cutting techniques with laser cutting. The purpose of this experiment is to observe cutting quality for intrusive igneous rocks using a high-power multimode fiber laser. The cutting quality, in terms of kerf width and penetration depth, resulted from different scanning speeds and was studied and compared. The specimens used in this study were gabbro, granite, and diorite, which are widely applied in the construction industry because of their high compressive strength and beautiful textures. Energy-dispersive X-ray Spectroscopy (EDX) analyses were conducted to observe the chemical content of three different areas, the melting area, the burnt area, and a non-processed area, for each rock specimen. The study of the compositional changes in each area will also go over the cutting quality of each rock specimen at different scanning speeds. According to the experimental results, the kerf widths of the specimens gradually decrease as the scanning speeds increase. The penetration depths into the specimens sharply decrease as scanning speeds increase. From a study of their compositional changes, it is found that the cutting quality for each rock depends on their silica content. This study summarizes that the cutting quality for a rock specimen greatly depends on the scanning speed of the laser cutting.
A Low-Dimensional Layout of Magnetic Units as Nano-Systems of Combinatorial Logic: Numerical Simulations
Authors: Kuźma Dominika , Kowalczyk Paweł , Cpałka Krzysztof , Laskowski Łukasz
Published: May 2021

Nanotechnology has opened numerous ways for physically realizing very sophisticated nanodevices that can be fabricated exclusively using molecular engineering methods. However, the synthesis procedures that lead to the production of nanodevices are usually complicated and time consuming. For this reason, the destination materials should be well designed. Therefore, numerical simulations can be invaluable. In this work, we present numerical simulations of the magnetic behaviour of magnetic units shaped into nanometric strips as a low dimensional layout that can be used as nano-systems of combinatorial logic. We showed that magnetic layouts that contain fewer than 16 magnetic units can take on a specific configuration as a response to the input magnetic field. Such configuration can be treated as an output binary word. The layouts that contained various numbers of magnetic units showed different switching characteristics (utterly different order of inverting of strips’ magnetic moments), thus creating numerous combinations of the output binary words in response to the analog magnetic signal. The number of possible output binary words can be increased even more by adding parameters––the system’s initial magnetic configuration. The physical realization of the model presented here can be used as a very simple and yet effective encryption device that is based on nanometric arrays of magnetic units rather than an integrated circuit. The same information, provided by the proposed system, can be utilized for the construction of a nano-sensor for measuring of magnetic field with the possibility of checking also the history of magnetization.
Mining Indonesian Microbial Biodiversity for Novel Natural Compounds by a Combined Genome Mining and Molecular Networking Approach
Authors: Handayani Ira , Saad Hamada , Ratnakomala Shanti , Lisdiyanti Puspita , Kusharyoto Wien , Krause Janina , Kulik Andreas , Wohlleben Wolfgang , Aziz Saefuddin , Gross Harald , Gavriilidou Athina , Ziemert Nadine , Mast Yvonne
Published: May 2021

Indonesia is one of the most biodiverse countries in the world and a promising resource for novel natural compound producers. Actinomycetes produce about two thirds of all clinically used antibiotics. Thus, exploiting Indonesia’s microbial diversity for actinomycetes may lead to the discovery of novel antibiotics. A total of 422 actinomycete strains were isolated from three different unique areas in Indonesia and tested for their antimicrobial activity. Nine potent bioactive strains were prioritized for further drug screening approaches. The nine strains were cultivated in different solid and liquid media, and a combination of genome mining analysis and mass spectrometry (MS)-based molecular networking was employed to identify potential novel compounds. By correlating secondary metabolite gene cluster data with MS-based molecular networking results, we identified several gene cluster-encoded biosynthetic products from the nine strains, including naphthyridinomycin, amicetin, echinomycin, tirandamycin, antimycin, and desferrioxamine B. Moreover, 16 putative ion clusters and numerous gene clusters were detected that could not be associated with any known compound, indicating that the strains can produce novel secondary metabolites. Our results demonstrate that sampling of actinomycetes from unique and biodiversity-rich habitats, such as Indonesia, along with a combination of gene cluster networking and molecular networking approaches, accelerates natural product identification.
Rare Intercondylar Distal Femoral Brodie’s Abscess in a 21-Year-Old Man Who Refused Medical Care for Three Years after Initial Symptoms
Authors: Hogea Bogdan Gheorghe , Patrascu Jenel Marian , Lazarescu Adrian Emil , El Mehdi Louchi , Bolovan Andrei Daniel , Hogea Lavinia Maria , Ilie Adrian Cosmin , Andor Bogdan Corneliu , Patrascu Jenel Marian
Published: May 2021

Brodie’s abscess is a rare form of sub-acute osteomyelitis that implies the collection of pus inside bone tissue. The present paper presents an extremely rare case of Brodie’s abscess located in the distal femur in a young male patient who refused medical care for three years and presented directly with spontaneous fistula and septic complications. Laboratory tests also suggested chronic septic alterations. Complex imaging investigations including X-ray (RX), computer tomography (CT) and Magnetic Resonance imaging (MRI) confirmed the diagnosis with characteristic aspects, such as the penumbra sign on the T1 weighted MRI image. Management included aggressive debridement, defect reconstruction, and long-term specific antibiotics according to culture harvested intra-operatively. Evolution was positive with inflammatory blood tests returning to physiological values within four weeks and patient full recovery within six months, without any physical deficits. The novelty aspect found in this case presentation is represented by the long-term natural evolution of this pathology, and the fact that even in these conditions, the Brodie’s abscess did not evolve into a ‘malignant’ septic condition, but remained rather benign until the spontaneous fistula prompted the patient to seek medical care.
Plant-Derived Extracellular Vesicles: Current Findings, Challenges, and Future Applications
Authors: Kameli Nader , Dragojlovic-Kerkache Anya , Savelkoul Paul , Stassen Frank R.
Published: May 2021

In recent years, plant-derived extracellular vesicles (PDEVs) have gained the interest of many experts in fields such as microbiology and immunology, and research in this field has exponentially increased. These nano-sized particles have provided researchers with a number of interesting findings, making their application in human health and disease very promising. Both in vitro and in vivo experiments have shown that PDEVs can exhibit a multitude of effects, suggesting that these vesicles may have many potential future applications, including therapeutics and nano-delivery of compounds. While the preliminary results are promising, there are still some challenges to face, such as a lack of protocol standardization, as well as knowledge gaps that need to be filled. This review aims to discuss various aspects of PDEV knowledge, including their preliminary findings, challenges, and future uses, giving insight into the complexity of conducting research in this field.
On the Electrical Resistance Relaxation of 3D-Anisotropic Carbon-Fiber-Filled Polymer Composites Subjected to External Electric Fields
Authors: Huang Pei , Cao Yingze , Xia Zhidong , Wang Pengfei , Chen Shaosong
Published: May 2021

Flexible composites as sensors are applied under a small voltage, but the effect of the external electrical field on the resistance is always ignored and unexplored by current research. Herein, we investigate the electrical resistance relaxation of anisotropic composites when they are subjected to an external electric field. The anisotropic composites were 3D-printed based on carbon-fiber-filled silicon rubber. Constant DC voltages were applied to the composites, and the output electrical current increased with time, namely the electrical resistance relax with time. The deflection and migration of carbon fibers are dominantly responsible for the resistance relaxation, and the angle’s evolution of a carbon fiber, under the application and removal of the electrical field, was well observed. The other factor hindering the resistance relaxation is the increased temperature originating from the Joule heating effect. This work provides a new understanding in the working duration and the static characteristics of flexible composites.
Rapid Production and Purification of Dye-Loaded Liposomes by Electrodialysis-Driven Depletion
Authors: Abatchev Gamid , Bogard Andrew , Hutchinson Zoe , Ward Jason , Fologea Daniel
Published: May 2021

Liposomes are spherical-shaped vesicles that enclose an aqueous milieu surrounded by bilayer or multilayer membranes formed by self-assembly of lipid molecules. They are intensively exploited as either model membranes for fundamental studies or as vehicles for delivery of active substances in vivo and in vitro. Irrespective of the method adopted for production of loaded liposomes, obtaining the final purified product is often achieved by employing multiple, time consuming steps. To alleviate this problem, we propose a simplified approach for concomitant production and purification of loaded liposomes by exploiting the Electrodialysis-Driven Depletion of charged molecules from solutions. Our investigations show that electrically-driven migration of charged detergent and dye molecules from solutions that include natural or synthetic lipid mixtures leads to rapid self-assembly of loaded, purified liposomes, as inferred from microscopy and fluorescence spectroscopy assessments. In addition, the same procedure was successfully applied for incorporating PEGylated lipids into the membranes for the purpose of enabling long-circulation times needed for potential in vivo applications. Dynamic Light Scattering analyses and comparison of electrically-formed liposomes with liposomes produced by sonication or extrusion suggest potential use for numerous in vitro and in vivo applications.
Metabolic Response of Pancreatic Carcinoma Cells under Treatment with Dichloroacetate
Authors: Feuerecker Benedikt , Biechl Philipp , Veltkamp Christian , Saur Dieter , Eisenreich Wolfgang
Published: May 2021

In modern oncology, the analysis and evaluation of treatment response are still challenging. Hence, we used a 13C-guided approach to study the impacts of the small molecule dichloroacetate (DCA) upon the metabolic response of pancreatic cancer cells. Two different oncogenic PI3K-driven pancreatic cancer cell lines, 9580 and 10,158, respectively, were treated with 75 mM DCA for 18 h. In the presence of [U-13C6]glucose, the effects of DCA treatment in the core carbon metabolism were analyzed in these cells using gas chromatography–mass spectrometry (GC/MS). 13C-enrichments and isotopologue profiles of key amino acids revealed considerable effects of the DCA treatment upon glucose metabolism. The DCA treatment of the two pancreatic cell lines resulted in a significantly decreased incorporation of [U-13C6]glucose into the amino acids alanine, aspartate, glutamate, glycine, proline and serine in treated, but not in untreated, cancer cells. For both cell lines, the data indicated some activation of pyruvate dehydrogenase with increased carbon flux via the TCA cycle, but also massive inhibition of glycolytic flux and amino acid biosynthesis presumably by inhibition of the PI3K/Akt/mTORC axis. Together, it appears worthwhile to study the early treatment response in DCA-guided or accompanied cancer therapy in more detail, since it could open new avenues for improved diagnosis and therapeutic protocols of cancer.
High-Consistency Optical Fiber Fabry–Perot Pressure Sensor Based on Silicon MEMS Technology for High Temperature Environment
Authors: Feng Fei , Jia Pinggang , Qian Jiang , Hu Zhengpeng , An Guowen , Qin Li
Published: May 2021

This paper proposes a high-temperature optical fiber Fabry–Perot pressure sensor based on the micro-electro-mechanical system (MEMS). The sensing structure of the sensor is composed of Pyrex glass wafer and silicon wafer manufactured by mass micromachining through anodic bonding process. The separated sensing head and the gold-plated fiber are welded together by a carbon dioxide laser to form a fiber-optic Fabry–Perot high temperature pressure sensor, which uses a four-layer bonding technology to improve the sealing performance of the Fabry–Perot cavity. The test system of high temperature pressure sensor is set up, and the experimental data obtained are calculated and analyzed. The experimental results showed that the maximum linearity of the optical fiber pressure sensor was 1% in the temperature range of 20–400 °C. The pressure sensor exhibited a high linear sensitivity of about 1.38 nm/KPa at room temperature at a range of pressures from approximarely 0-to 1 MPa. The structure of the sensor is characterized by high consistency, which makes the structure more compact and the manufacturing process more controllable.
Heterogeneously-Integrated Optical Phase Shifters for Next-Generation Modulators and Switches on a Silicon Photonics Platform: A Review
Authors: Kim Younghyun , Han Jae-Hoon , Ahn Daehwan , Kim Sanghyeon
Published: May 2021

The realization of a silicon optical phase shifter marked a cornerstone for the development of silicon photonics, and it is expected that optical interconnects based on the technology relax the explosive datacom growth in data centers. High-performance silicon optical modulators and switches, integrated into a chip, play a very important role in optical transceivers, encoding electrical signals onto the light at high speed and routing the optical signals, respectively. The development of the devices is continuously required to meet the ever-increasing data traffic at higher performance and lower cost. Therefore, heterogeneous integration is one of the highly promising approaches, expected to enable high modulation efficiency, low loss, low power consumption, small device footprint, etc. Therefore, we review heterogeneously integrated optical modulators and switches for the next-generation silicon photonic platform.
Breaking the Third Wall: Implementing 3D-Printing Techniques to Expand the Complexity and Abilities of Multi-Organ-on-a-Chip Devices
Authors: Goldstein Yoel , Spitz Sarah , Turjeman Keren , Selinger Florian , Barenholz Yechezkel , Ertl Peter , Benny Ofra , Bavli Danny
Published: May 2021

The understanding that systemic context and tissue crosstalk are essential keys for bridging the gap between in vitro models and in vivo conditions led to a growing effort in the last decade to develop advanced multi-organ-on-a-chip devices. However, many of the proposed devices have failed to implement the means to allow for conditions tailored to each organ individually, a crucial aspect in cell functionality. Here, we present two 3D-print-based fabrication methods for a generic multi-organ-on-a-chip device: One with a PDMS microfluidic core unit and one based on 3D-printed units. The device was designed for culturing different tissues in separate compartments by integrating individual pairs of inlets and outlets, thus enabling tissue-specific perfusion rates that facilitate the generation of individual tissue-adapted perfusion profiles. The device allowed tissue crosstalk using microchannel configuration and permeable membranes used as barriers between individual cell culture compartments. Computational fluid dynamics (CFD) simulation confirmed the capability to generate significant differences in shear stress between the two individual culture compartments, each with a selective shear force. In addition, we provide preliminary findings that indicate the feasibility for biological compatibility for cell culture and long-term incubation in 3D-printed wells. Finally, we offer a cost-effective, accessible protocol enabling the design and fabrication of advanced multi-organ-on-a-chip devices.
Enhancing Electrical Outputs of Piezoelectric Nanogenerators by Controlling the Dielectric Constant of ZnO/PDMS Composite
Authors: Amangeldinova Yerkezhan , Aben Dimaral , Ma Xiaoting , Ahn Heesang , Kim Kyujung , Shin Dong-Myeong , Hwang Yoon-Hwae
Published: May 2021

Structural optimizations of the piezoelectric layer in nanogenerators have been predicted to enhance the output performance in terms of the figure of merit. Here, we report the effect of dielectric constant on electrical outputs of piezoelectric nanogenerator using ZnO/PDMS composites with varied ZnO coverages. The dielectric constant of piezoelectric layers was adjusted from 3.37 to 6.75. The electrical output voltage of 9 mV was achieved in the nanogenerator containing the ZnO/PDMS composite with the dielectric constant of 3.46, which is an 11.3-fold enhancement compared to the value of the nanogenerator featuring the composite with high dielectric constants. Significantly, lowering the dielectric constant of the piezoelectric layer improves the electrical output performance of piezoelectric nanogenerators.
Additive Manufacture of Small-Scale Metamaterial Structures for Acoustic and Ultrasonic Applications
Authors: Gardiner Alicia , Daly Paul , Domingo-Roca Roger , Windmill James , Feeney Andrew , Jackson-Camargo Joseph
Published: May 2021

Acoustic metamaterials are large-scale materials with small-scale structures. These structures allow for unusual interaction with propagating sound and endow the large-scale material with exceptional acoustic properties not found in normal materials. However, their multi-scale nature means that the manufacture of these materials is not trivial, often requiring micron-scale resolution over centimetre length scales. In this review, we bring together a variety of acoustic metamaterial designs and separately discuss ways to create them using the latest trends in additive manufacturing. We highlight the advantages and disadvantages of different techniques that act as barriers towards the development of realisable acoustic metamaterials for practical audio and ultrasonic applications and speculate on potential future developments.
Bioleaching of Gold from Silicate Ore by Macrococcus caseolyticus and Acinetobacter calcoaceticus: Effect of Medium, Amino Acids and Growth Supernatant
Authors: Kudpeng Kanjana , Thayanukul Parinda , Thiravetyan Paitip
Published: May 2021

The aims of this work were to study the gold leaching by the isolated bacteria from silicate ore. Three strains were isolated and identified as Macrococcus caseolyticus, Acinetobacter calcoaceticus, and Bacillus sp. MBEA40. However, only M. caseolyticus and A. calcoaceticus were capable of gold bioleaching. In order to examine only the effect of microorganisms involved in the gold bioleaching process, minimal medium and ethanol mineral salt medium without amino acids were used for culturing M. caseolyticus and A. calcoaceticus, respectively. The result showed that the growth supernatant (in the absence of microorganisms) of both strains might be more suitable to leaching gold from ore than leaching by microorganisms (in the presence of microorganisms) directly. This might be due to the fact that there is no interference of gold absorption and metal toxicity in microorganisms in the long-term operation. The result also confirmed that amino acids/peptides/proteins produced by microorganisms might be involved in gold bioleaching, as shown in the high-performance liquid chromatography (HPLC) results. The Fourier transform infrared spectroscopy (FTIR) study also found that amine groups and carboxylic groups played important roles in gold bioleaching by M. caseolyticus and A. calcoaceticus. In addition, the bioleaching process had significantly higher gold leaching than mixed pure amino acids due to the growth supernatant containing mixed amino acids/peptides/proteins and other compounds. Therefore, the growth supernatant of M. caseolyticus and A. calcoaceticus can be applied in gold bioleaching under neutral pH conditions, which is considered to be a safe, not corrosive, and environmentally friendly leaching process. This study is also needed further study in order to increase the percentage of gold bioleaching and decrease times.
Simple Determination of Gold Nanocrystal Dimensions by Analytical Ultracentrifugation via Surface Ligand-Solvent Density Matching
Authors: González-Rubio Guillermo , Hilbert Holger , Rosenberg Rose , Ni Bing , Fuhrer Lisa , Cölfen Helmut
Published: May 2021

Analytical ultracentrifugation (AUC) is a powerful technique to observe colloidal nanocrystals (NCs) directly in solution and obtain critical information about their physical-chemical properties. Nevertheless, a more comprehensive implementation of AUC for the characterisation of such a class of crystalline colloids has been traditionally impaired by the requirement of having a priori knowledge of the complex, multilayered structure formed by NC in solution. This includes the nature (density and mass) of the surface ligands (SLs) that provide NC colloidal stability and the shell of solvent molecules formed on it. Herein, we propose a methodology to determine the NCs size by using SLs with a density equal to that of the solvent. Thereby, the buoyancy force of the SL shell is neutral, and the density of the NCs is sufficient a priori knowledge to calculate their related mass and size distributions. The simplicity and reliability of the method are evaluated with cetyltrimethylammonium bromide (CTAB) stabilized spherical gold NCs (AuNCs) of dimensions ranging from 1 to 17 nm. The proposed method has great potential to be transferred to any non-crystalline and crystalline colloids of different nature and composition, which have a density that is equal to the bulk and can be stabilized by SLs having a density that matches that of the solvent.
High-Capacity and Long-Lifespan Aqueous LiV3O8/Zn Battery Using Zn/Li Hybrid Electrolyte
Authors: Pang Qiang , Yu Xiangyu , Zhang Shijing , He Wei , Yang Siyu , Fu Yao , Tian Ying , Xing Mingming , Luo Xixian
Published: May 2021

Aqueous zinc-ion batteries (AZIBs) are promising candidates for large-scale energy storage because of their low cost and high safety. However, their practical applications are impeded by low energy density and short service life. Here, an aqueous Zn2+/Li+ hybrid-ion battery is fabricated using the LiV3O8 nanorods as the cathode, metallic Zn as the anode, and 3 M Zn(OTf)2 + 0.5 M LiOTf aqueous solution as the electrolyte. Compared with the batteries using pure 3 M Zn(OTf)2 electrolyte, the cycle performance of the hybrid-ion battery is significantly improved. After 4000 cycles at 5 A g1, the remaining capacity is 163.9 mA h g−1 with impressive capacity retention of 87.0%. Ex-situ XRD, ex-situ XPS, and SEM tests demonstrate that the hybrid electrolyte can inhibit the formation of the irreversible Zn3(OH)2V2O7·2H2O by-product and restrict Zn dendrite growth during cycling, thereby improving the cycle performance of the batteries.
Waterborne Graphene- and Nanocellulose-Based Inks for Functional Conductive Films and 3D Structures
Authors: González-Domínguez Jose M. , Baigorri Alejandro , Álvarez-Sánchez Miguel Á. , Colom Eduardo , Villacampa Belén , Ansón-Casaos Alejandro , García-Bordejé Enrique , Benito Ana M. , Maser Wolfgang K.
Published: May 2021

In the vast field of conductive inks, graphene-based nanomaterials, including chemical derivatives such as graphene oxide as well as carbon nanotubes, offer important advantages as per their excellent physical properties. However, inks filled with carbon nanostructures are usually based on toxic and contaminating organic solvents or surfactants, posing serious health and environmental risks. Water is the most desirable medium for any envisioned application, thus, in this context, nanocellulose, an emerging nanomaterial, enables the dispersion of carbon nanomaterials in aqueous media within a sustainable and environmentally friendly scenario. In this work, we present the development of water-based inks made of a ternary system (graphene oxide, carbon nanotubes and nanocellulose) employing an autoclave method. Upon controlling the experimental variables, low-viscosity inks, high-viscosity pastes or self-standing hydrogels can be obtained in a tailored way. The resulting inks and pastes are further processed by spray- or rod-coating technologies into conductive films, and the hydrogels can be turned into aerogels by freeze-drying. The film properties, with respect to electrical surface resistance, surface morphology and robustness, present favorable opportunities as metal-free conductive layers in liquid-phase processed electronic device structures.
Biological Potential of Polyethylene Glycol (PEG)-Functionalized Graphene Quantum Dots in In Vitro Neural Stem/Progenitor Cells
Authors: Ji Yunseong , Li Yu-Meng , Seo Jin Gwan , Jang Tae-Su , Knowles Jonathan Campbell , Song Sung Ho , Lee Jung-Hwan
Published: May 2021

Stem cell therapy is one of the novel and prospective fields. The ability of stem cells to differentiate into different lineages makes them attractive candidates for several therapies. It is essential to understand the cell fate, distribution, and function of transplanted cells in the local microenvironment before their applications. Therefore, it is necessary to develop an accurate and reliable labeling method of stem cells for imaging techniques to track their translocation after transplantation. The graphitic quantum dots (GQDs) are selected among various stem cell labeling and tracking strategies which have high photoluminescence ability, photostability, relatively low cytotoxicity, tunable surface functional groups, and delivering capacity. Since GQDs interact easily with the cell and interfere with cell behavior through surface functional groups, an appropriate surface modification needs to be considered to get close to the ideal labeling nanoprobes. In this study, polyethylene glycol (PEG) is used to improve biocompatibility while simultaneously maintaining the photoluminescent potentials of GQDs. The biochemically inert PEG successfully covered the surface of GQDs. The PEG-GQDs composites show adequate bioimaging capabilities when internalized into neural stem/progenitor cells (NSPCs). Furthermore, the bio-inertness of the PEG-GQDs is confirmed. Herein, we introduce the PEG-GQDs as a valuable tool for stem cell labeling and tracking for biomedical therapies in the field of neural regeneration.
Examining the Relationship between Sugar Content, Packaging Features, and Food Claims of Breakfast Cereals
Authors: Prada Marília , Saraiva Magda , Viegas Claúdia , Cavalheiro Bernardo , Garrido Margarida
Published: May 2021

Excessive free-sugar intake has become highly prevalent in numerous countries, and Portugal is not the exception. One product category that contributes to the daily intake of free sugars is breakfast cereals. In the current work, we identified 289 exemplars from two major retailers in Portugal and collected information on their nutritional profile (e.g., sugar, salt, fiber per 100 g), price, packaging features, type of food claims present (e.g., statements about the composition, sensory features, the origin of the product), and ingredients list. Overall, the sugar content of breakfast cereals was high (Mean = 19.9 g), and less than 10% of the products complied with the current national guidelines (i.e., 5 g of sugar per 100 g of product). Sugar (or other sugar sources) was listed in the top three ingredients for over 85% of the products. On average, each product included about four claims (Mean = 3.9), and sugar content was lower when the claims were related to the product composition. Critically, the sugar content was particularly high for children-oriented products (Mean = 26.4 g). Correlation analysis showed that breakfast cereals with higher sugar content also were cheaper and had lower quantities of fiber, proteins, and salt. Our findings suggest the need to implement strategies to reduce sugar in this product category (e.g., incentivize manufacturers to reformulate products). Also, our results may inform strategies aimed at promoting consumers’ awareness about the sugar content in breakfast cereals and other processed foods, facilitating healthier decision-making.
Diet Quality Indices and Physical Activity Levels Associated with Adequacy of Gestational Weight Gain in Pregnant Women with Gestational Diabetes Mellitus
Authors: Almeida Vanessa Averof Honorato de , Costa Rafaela Alkmin da , Paganoti Cristiane de Freitas , Mikami Fernanda Cristina , Sousa Ana Maria da Silva , Peres Stela Verzinhasse , Lopes Marco Antonio Borges , Francisco Rossana Pulcineli Vieira
Published: May 2021

The aim of this study was to evaluate the Diet Quality Index (DQI) and the Physical Activity (PA) levels associated with adequacy of gestational weight gain in pregnant women with gestational diabetes mellitus (GDM). A total of 172 pregnant women with a single fetus and a diagnosis of GDM participated. Food intake was self-reported on the food frequency questionnaire and DQI was quantified using the index validated and revised for Brazil (DQI-R). To assess PA, the Pregnancy Physical Activity Questionnaire was administered. Gestational weight gain was classified, following the criteria of the Institute of Medicine, into adequate (AWG), insufficient (IWG), or excessive (EWG) weight gain. A multinomial logistic regression analysis was performed, with level of significance <0.05. The participants were divided into 3 groups: AWG (33.1%), IWG (27.3%), and EWG (39.5%). The analysis indicated that if the pregnant women PA fell into tertile 1 or 2, then they had a greater chance of having IWG, whereas those with the lowest scores on the DQI-R, whose PA fell into tertile 2, and pregestational obesity women had the greatest chance of having EWG. This study has shown that low PA levels may contribute towards IWG. On the other hand, a low final DQI-R score, representing inadequate food habits, low PA levels, and pregestational obesity may increase the chance of EWG in patients with GDM.
Dietary Methyl-Group Donor Intake and Breast Cancer Risk in the European Prospective Investigation into Cancer and Nutrition (EPIC)
Authors: Van Puyvelde Heleen , Papadimitriou Nikos , Clasen Joanna , Muller David , Biessy Carine , Ferrari Pietro , Halkjær Jytte , Overvad Kim , Tjønneland Anne , Fortner Renée T. , Katzke Verena , Schulze Matthias B. , Chiodini Paolo , Masala Giovanna , Pala Valeria , Sacerdote Carlotta , Tumino Rosario , Bakker Marije F. , Agudo Antonio , Ardanaz Eva , Chirlaque López María Dolores , Sánchez Maria-Jose , Ericson Ulrika , Gylling Björn , Karlsson Therese , Manjer Jonas , Schmidt Julie A. , Nicolas Geneviève , Casagrande Corinne , Weiderpass Elisabete , Heath Alicia K. , Godderis Lode , Van Herck Koen , De Bacquer Dirk , Gunter Marc J. , Huybrechts Inge
Published: May 2021

(1) Background: Methyl-group donors (MGDs), including folate, choline, betaine, and methionine, may influence breast cancer (BC) risk through their role in one-carbon metabolism; (2) Methods: We studied the relationship between dietary intakes of MGDs and BC risk, adopting data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort; (3) Results: 318,686 pre- and postmenopausal women were followed between enrolment in 1992–2000 and December 2013–December 2015. Dietary MGD intakes were estimated at baseline through food-frequency questionnaires. Multivariable Cox proportional hazards regression models were used to quantify the association between dietary intake of MGDs, measured both as a calculated score based on their sum and individually, and BC risk. Subgroup analyses were performed by hormone receptor status, menopausal status, and level of alcohol intake. During a mean follow-up time of 14.1 years, 13,320 women with malignant BC were identified. No associations were found between dietary intakes of the MGD score or individual MGDs and BC risk. However, a potential U-shaped relationship was observed between dietary folate intake and overall BC risk, suggesting an inverse association for intakes up to 350 µg/day compared to a reference intake of 205 µg/day. No statistically significant differences in the associations were observed by hormone receptor status, menopausal status, or level of alcohol intake; (4) Conclusions: There was no strong evidence for an association between MGDs involved in one-carbon metabolism and BC risk. However, a potential U-shaped trend was suggested for dietary folate intake and BC risk. Further research is needed to clarify this association.
Low- and No-Calorie Sweetener (LNCS) Consumption Patterns Amongst the Spanish Adult Population
Authors: Redruello-Requejo Marina , González-Rodríguez María , Samaniego-Vaesken Mª de Lourdes , Montero-Bravo Ana , Partearroyo Teresa , Varela-Moreiras Gregorio
Published: May 2021

Low- and no-calorie sweeteners (LNCS) are a group of food additives characterized by their high sweetness intensity and virtually zero caloric content, attributes that make them potential substitutes for added sugars in processed foods and beverages. However, there is currently scarce information available about both the different LNCS used in food products available in Spain and their consumption patterns. Prompted by these reasons, the aim of this research work was to identify the presence and consumption of LNCS in food and beverages consumed by a representative sample of the Spanish adult population (n = 507). For this purpose, a Food Frequency Questionnaire was carried out. Overall, it was found that 4.5% of the foods and 22.3% of the beverages consumed by the surveyed population contained LNCS. The food groups that presented the highest percentage of daily servings containing LNCS were non-alcoholic beverages such as soft drinks and juices (36.1%); sugars and sweets such as chocolates, candies, or chewing gum (14.2%); milk and dairy products (7.0%); meat and derivative products (5.1%); cereals and derivatives (4.3%); appetizers (1.7%); and, finally, sauces and condiments such as ketchup or mustard (1.0%). The main LNCS consumed were acesulfame-K, sucralose, sorbitol, aspartame, and cyclamate, although their prevalence of use differs greatly among foods, beverages, or tabletop sweeteners. Our results show the great diversity of food groups that are currently including these compounds as ingredients. Consequently, there is a need for these food additives to be included in food composition databases, which should be regularly updated to include LNCS in order to facilitate their assessment and monitoring in dietary nutritional surveys.