bluuebunny/crossref_metadata_2025 huggingface dataset:
The Application and Working Principles of Passive Pumping Mechanism
Authors: Bai Yunjin , Zhang Wangzeyi
Published: March 2022

Passive pumping mechanisms are vital for today’s experiment and studies in the microfludics fields. This Paper is a review paper about the passive pumping mechanism (as known as PPM) with variety types of driven force used in microfludics experiment. The goal of such article was to review the already existed PPM. In doing so, the paper summed up different types of PPM, explained their working principles and showed some of applications of PPM. The history, development and the limitation were also discussed in the paper.
Safety evaluation of production casing in staged stimulation of ultra-deep horizontal wells
Authors: Fan Wei , Liu Hongtao , Geng Hailong , Zeng Nu , Lou Erbiao , Liu Wenchao
Published: March 2022

In view of the influence of high temperature formation fluid during the staged stimulation of ultra-deep oil and gas wells, the change of wellbore temperature field may cause casing rupture and compression. Based on the law of momentum conservation and energy conservation, an iterative calculation model of deep annulus pressure is established to study the variation law of confined annulus between packers. According to casing wear shape, the calculation model of residual strength and safety evaluation are established. The casing annulus pressure of L-3 well is predicted by casing annulus pressure prediction model, and the sensitivity analysis is carried out. The results show that the errors between the measured and predicted values of casing annulus are within the allowable range and the model accuracy is high. The effects of annulus liquid and tubing coefficients on annulus pressure are studied, and the effect of wear depth on casing safety factor is studied. In this paper, the effects of annulus pressure and casing wear on wellbore integrity in ultra-deep wells are considered comprehensively, and a method for production casing safety evaluation is developed.
The Design of Dynamic Thermal Metadevice with Vertical Rotation Coupling Mechanisms for Switchable Effects
Authors: Wang Shiyan
Published: March 2022

Recently, thermal metamaterials which can control heat flux at will have attracted many researchers and they can be used in many thermal application scenarios such as thermal concentration and thermal cloak. In this paper, this dynamic thermal metadevice with a vertical rotation coupling component can achieve the target of switchable thermal effect based on effective medium theory and scattering cancellation method. Firstly, this metadvice can adjust the effective thermal conductivities in the region with two novel vertical rotation rings by tuning the rotational velocity. Additionally, an almost undistorted and nonspinning thermal field in the central region can be obtained via this novel design. Furthermore, compared with the previous work, this metadevice can implement the continuous modulation of the effective thermal conductivity at will by adopting a vertical rotation scheme, realizing various thermal functionalities such as thermal concentration and thermal cloak. Then, we demonstrate the switchable effect of this dynamic thermal metadevice in simulations. Meanwhile, the variations of temperature along the measured horizonal line are also shown in simulations. In contrast to previous approaches, this dynamic thermal metadevice may provide more dynamic thermal manipulation inspirations for designing novel multifunctional thermal metadevices.
Numerical simulation of structure design of magnetoelectric composite ultrasonic levitation device based on multi-physical field coupling
Authors: Qu Zhuohang , Zhao Rongguo , Wen Jianbiao
Published: March 2022

Aiming at the coupling simulation problem that ignores the acoustic structure boundary in the traditional acoustic suspension simulation, based on the magnetostrictive effect, the piezoelectric effect, and the acoustic-structure coupling model, this paper uses a magnetoelectric structure composed of the magnetostrictive material Terfenol-D and the piezoelectric ceramic PZT-5H. The composite material is used as, and the magneto-electric-acoustic fully coupled model of the magneto-electric composite material is established and compared with the one-way coupling model; The particle levitation of magnetoelectric composite materials in the multi-field coupling environment of the magnetic field, electric field, sound field, and displacement field was simulated and calculated; the influence of different widths of magneto-electric composite materials and the size of the resonant cavity on the effect of acoustic levitation was analyzed, and the best results were obtained. The geometric parameters required for optimal suspension are analyzed; the sound pressure output performance of the overall magnetoelectric composite ultrasonic suspension device under the optimal size and the judgment of the suspension position is analyzed, and I displayed the good suspension of the simulated particles in the sound field visually. The research results show that the difference in the amplitude output of the transducer will affect the sound pressure output performance of the transducer, and there is a large error in the one-way coupling; the magnetoelectric composite material can be used as an ultrasonic transducer to achieve acoustic suspension, and suspended particles It shows a good acoustic levitation effect in the simulation. The fully coupled simulation of ultrasonic transducers and the research on such ultrasonic transducers can open new ideas for the research and development of new ultrasonic transducers in the future.
Condensation heat transfer deterioration on superhydrophobic surface with dense nanostructures
Authors: Kan Tongli , Xu Jinliang , Xie Jian
Published: March 2022

Superhydrophobic surface with dense nanostructures was fabricated on copper substrate by template-assisted electrochemical deposition. During deposition process, bubbles generated and stayed at some regions to prevent the fabrication of nanostructure, yielding heterogeneous surface. To prepare homogeneous surface, the electrolyte composition and plating voltage are optimized. Repeated experiments of condensation heat transfer on superhydrophobic surface were performed. The heat transfer performance is deteriorated during experiments. Compared with hydrophilic and smooth surface, heat transfer coefficient on fresh superhydrophobic surface was improved by 154.3%, maximally. However, the heat transfer coefficient of superhydrophobic surface after repeated tests behaves only maximum 67.2% improvement. To explore the mechanism of heat transfer deterioration, SEM images and EDS elemental analysis were used. There is no obvious change of nanostructure after repeated experiments. However, the polymer attached on nanostructure to provide hydrophobicity is destroyed. This paper warns that the robustness of both nanostructure and polymer need to be considered to fabricate superhydrophobic surface with excellent condensation heat transfer performance.
Experimental Study on Erosion of String Inner Wall in Perforation Interval in Liquid-Solid Two-Phase Flow
Authors: Zhang Kui , Wang Junchao , Yuan Liang , Mu Lingyu , Cheng Jiarui , Wei Wenlan
Published: March 2022

In the process of large displacement fracture injection, high flow velocity sand-carrying fluid causes serious erosion corrosion to the borehole. Based on the high-speed liquid-solid two-phase erosion experiments, the erosion experiments of single-hole set with flow velocity, sand concentration and grain size, and the three-dimensional profile scanning of the eroded orifice were carried out to investigate the erosion and corrosion expansion law of the high-speed jet orifice. The study shows that the erosion rate increases with the increase of discharge volume, sand concentration and particle size, and the change of discharge volume and sand concentration has the most significant effect on the erosion of the hole. The prediction of the hole expansion law of single hole with sand liquid injection shows that the hole diameter expands to 13mm-19mm after 90min of construction of 8 clusters of 24 holes, while the hole diameter expands to 11.7mm-12.8mm after 90min of construction of 3 clusters of 48 holes. 3 clusters of 48 holes have smaller hole diameter after the same construction time, which is better than 8 clusters of 24 densely packed holes.
First-principles study of resistive random access memory based on AlN
Authors: Shao Peng , Dai Yuehua , Li Xing , Yang Bin , Wang Xiaoqing
Published: March 2022

In this article, the properties of AlN-based RRAM and the effect of O doping on device performance were investigated. After determining the size of electrode and resistive layer through the calculation of LDOS and surface energy, the Ti/AlN and Pt/AlN interfaces were established by the calculation of the binding energy. Through the above steps, the RRAM model is finally established. The I-V curve obtained by calculation shows that the AlN-based RRAM has bipolar resistive switching characteristics. The device has a fairly high switch ratio (104). And its turn-on and turn-off threshold voltages are 1.7 V and 0.6 V, respectively. The calculation of DOS and charge density reveals that the resistance switching mechanism of the AlN-based RRAM is that N vacancies form a conductive path. Finally, by studying the influence of O doping on the formation energy of N vacancies, Electron localization function and migration energy, it is found that O doping can promote the conduction of the device and improve the uniformity of the conductive filaments.
Instability Analysis of Fluid-Conveying Functionally Graded Thin-Walled Pipes on Random Elastic Foundations
Authors: Cao Jianhua
Published: March 2022

The aims in this work are to study the effects of random variables and physical parameters on the critical fluid velocity of functionally graded material thin-walled pipes resting on random elastic foundations which carry the axial flow. The variation of the mean of the critical flow velocity with the spatial correlation length are monotonically increased or not monotonic which is conditional on the values of the coefficient of variation. The length of the intervals for purely ceramic or fully metal is shorter than these for other values of volume fraction index in which the mean of critical flow velocity is higher than that of the deterministic foundation stiffness. As the volume fraction index and temperature gradient of FGMs increase, the curves of the mean of critical flow velocity vary greatly for the fixed values of the coefficient of variation. The numerical results have been of practical interest for the design of the functionally graded pipes.
Experiment and simulation of microwave detection using IQ demodulation method for breast tumor screening
Authors: Li C.P. , Yao Y. , Li Z.H. , Cheng L. , Zhang Y. , Liu H.Q.
Published: March 2022

Breast cancer has become the most diagnosed cancer in the world. Microwave detection the breast tumor is attractive due to its high dielectric property contrast between different tissues of tumor. In this paper, we proposed an In-phase-Quadrature (IQ) demodulation-based method to detect the breast tumor with microwave at a frequency of 1.3 GHz. The microwave detection system consists of two signal generators, 12 transmitting/receiving antennas, two talent switches, a phantom and an IQ-Mixer. The amplitude information at the receiving antennas can be obtained by analyzing the difference frequency signals generated with two microwave signal generators. We also use the finite-difference time-domain (FDTD) method for simulation verification, which can simulate the propagation of the electromagnetic wave. Through experiments and simulations of microwave hardware system and FDTD method, it can be proved that the results are consistent. The experimental and simulation results show that when the tumor phantom diameter decreases or its depth from the receiving antenna increases, whether there is a tumor phantom can be clearly distinguished. Moreover, we also explore the effects of different tumor phantom locations on the receiving antennas. The results show that it is feasible to detect the breast tumor with the IQ demodulation method based on microwave.
Graphene oxide encapsulated forsterite scaffolds to improve mechanical properties and antibacterial behavior
Authors: Najafinezhad A , Bakhsheshi-Rad H R , Saberi A , Nourbakhsh A A , Daroonparvar M , Ismail Ahmad Fauzi , Sharif Safian , RamaKrishna Seeram , Dai Yunqian , Berto F
Published: March 2022

It is very desirable to have good antibacterial properties and mechanical properties at the same time for bone scaffolds. Graphene oxide (GO) can increase the mechanical properties and antibacterial performance, while forsterite (Mg2SiO4) as the matrix can increase forsterite/GO scaffolds’ biological activity for bone tissue engineering. Interconnected porous forsterite scaffolds were developed by space holder processes for bone tissue engineering in this research. The forsterite/GO scaffolds had a porosity of 76%–78% with pore size of 300–450 μm. The mechanism of the mechanical strengthening, antibacterial activity, and cellular function of the forsterite/GO scaffold was evaluated. The findings show that the compressive strength of forsterite/1 wt.% GO scaffold (2.4 ± 0.1 MPa) was significantly increased, in comparison to forsterite scaffolds without GO (1.4 ± 0.1 MPa). Validation of the samples’ bioactivity was attained by forming a hydroxyapatite layer on the forsterite/GO surface within in vitro immersion test. The results of cell viability demonstrated that synthesized forsterite scaffolds with low GO did not show cytotoxicity and enhanced cell proliferation. Antibacterial tests showed that the antibacterial influence of forsterite/GO scaffold was strongly correlated with GO concentration from 0.5 to 2 wt.%. The scaffold encapsulated with 2 wt.% GO had the great antibacterial performance with bacterial inhibition rate around 90%. As results show, the produced forsterite/1 wt.% GO can be an attractive option for bone tissue engineering.
Future increases in lightning ignition efficiency and wildfire occurrence expected from drier fuels in boreal forest ecosystems of western North America
Authors: Hessilt Thomas D , Abatzoglou John T , Chen Yang , Randerson James T , Scholten Rebecca C , van der Werf Guido , Veraverbeke Sander
Published: March 2022

Lightning-induced fire is the primary disturbance agent in boreal forests. Recent large fire years have been linked to anomalously high numbers of lightning-caused fire starts, yet the mechanisms regulating the probability of lightning ignition remain uncertain and limit our ability to project future changes. Here, we investigated the influence of lightning properties, landscape characteristics, and fire weather on lightning ignition efficiency—the likelihood that a lightning strike starts a fire—in Alaska, United States of America, and Northwest Territories, Canada, between 2001 and 2018. We found that short-term fuel drying associated with fire weather was the main driver of lightning ignition efficiency. Lightning was also more likely to ignite a wildfire in denser, evergreen forest areas. Under a high greenhouse gas emissions scenario, we predicted that changes in vegetation and fire weather increase lightning ignition efficiency by 14 ± 9% in Alaska and 31 ± 28% in the Northwest Territories per 1 °C warming by end-of-century. The increases in lightning ignition efficiency, together with a projected doubling of lightning strikes, result in a 39%–65% increase in lightning-caused fire occurrence per 1 °C warming. This implies that years with many fires will occur more frequently in the future, thereby accelerating carbon losses from boreal forest ecosystems.
Contribution of Constructed Wetlands for Reclaimed Water Production: A Review
Authors: Pinho Henrique J O , Mateus Dina M R
Published: April 2022

Freshwater scarcity is a growing threat to sustainable development, which can be mitigated by adequate management of water resources. Agriculture and related activities consist in the main use of freshwater, but several other human activities present relevant contributions. Because most of the water uses imply the generation of resultant wastewater, the production and use of reclaimed water by appropriate technologies can be part of the solution to that issue. Considering that the use of constructed wetlands (CWs) can be a relevant contribution to the production of reclaimed water, as an eco-friendly alternative to costly advanced water treatment technologies, this work is a review of the last decade of literature on the use of CWs to produce reclaimed water. The results point to a usual focus on the production of reclaimed water for agriculture or urban spaces irrigation. In order to potentiate a broader application of CWs, some directions of future research and use of this green technology are proposed.
Experimental characterisation of physical properties of different PLA filaments used in FFF 3D printing technology
Authors: Lang A
Published: March 2022

In the field of 3D printing, fused filament fabrication (FFF), many PLA filaments are offered by different providers. The physical properties of the filaments from various manufacturers differ significantly from each other. These differences have corresponding effects on the processing of the filaments, as well as on the quality of the final product. This article compares PLA filaments from different manufacturers and additionally gives an overview of their physical properties. The investigated properties were namely the melting point, cold crystallization, glass transition temperature, melt flow index and residual content. The results show the differences between the various manufacturers' specifications in the data sheets and point out others. The melt flow index in particular stands out here, which can have a strong influence on the printing process. The effect especially on the mechanical properties has to be determined in further investigations.
Digital service application for the recalibration of a machine tool through Augmented Reality-supported data acquisition
Authors: Arnold F , Lemme G , Hess M , Witt S , Ihlenfeldt S
Published: March 2022

The effort for checking and correcting the spatial movement accuracy of a processing machine with 5 axes is very high. Calibration and recalibration must be carried out directly on the machine by the machine supplier or a company specializing in this. This is associated with high personnel and long machine downtimes. These constraints can be improved by using modern methods. A consistent approach of an AR-supported measurement procedure for the preparation and execution of a required measurement run and the execution of the calibration itself as a digital service is presented. This enables rapid execution by the machine operator himself using a DoubleBallBar measurement system without the need of the presence of the machine manufacturer. The determination of the calibration parameters on the basis of the measurement data is then carried out by the machine manufacturer and provided as a service. The basis for such a secure and auditable service is a digital service platform. This serves as an intermediary between the user and the machine manufacturer and uses distributed ledger technology. The approach presented is the subject of current development work.
Establishing the machining process for complex aluminum alloy part made from plate raw material
Authors: Moldovan Ş A , Banica M , Năsui V
Published: March 2022

This paper presents a technical solution to establish the machining process for complex structural products made from aluminum alloy plates used in the aerospace industry. Those products have a very tight tolerance for geometrical deviations and positioning characteristics. To achieve a good product and ensure the machining process, repeatability is necessary to solve two issues: first, the temperature dilatation impact, and second the raw material behavior. To solve these problems, several tests were performed for products used in the aerospace industry. For deviations identification, all products were measured using a coordinate measuring machine, and the resulting report data was used for statistical analysis. Using this information, appropriate processing strategies were established. Through several tests and recording all dimensions changes during the milling process, good products were obtained, and it was ensured repeatability of the machining process.
Construction of surface layers with special properties in the hardening of steels
Authors: Volkov O , Knyazev S , Subbotina V , Iancu C , Gutsalenko Yu , Shelkovyi O , Strelchuk R.
Published: March 2022

Designing surface layers with special properties at strengthening of steels gives the chance to receive effective tools of a special purpose. The technological process of hardening by boron saturation of the jewellery tool - crimpings for fixing jewellery stones from carbon steel (0.7% C) is offered. Boron saturation of steel crimpings for fixing jewellery stones was performed before traditional hardening and low tempering. The microhardness of the surface layer of boron saturated steel has been more than doubled: at a depth of up to 50 μm – up to more than 16 GPa against 6 GPa for traditional hardening technology. Between the upper hardened layer and the unaltered inner metal, a transitional structure zone with tempering martensite is observed. This zone has a thickness of about 100 μm and an average microhardness in the range from 10 GPa to about 14 GPa.
Computer-aided methods for furniture decoration with traditional motifs of textile heritage
Authors: Lungu A , Gurău L , Georgescu S , Coşereanu C
Published: March 2022

The present paper introduces computer-aided methods for the transposition of ornaments inspired from the textile heritage into the surface furniture decoration. Using digital technology, the furniture industry may bring into modern life the traditional motifs, contributing thus to the preservation of the cultural heritage from the region Ţara Bârsei, located in Transylvania. Two motifs inspired by the traditional costumes from South-Eastern Transylvania were digitized using CorelDraw software. They were imported in AutoCAD and the information was transferred both to CNC router and laser equipment. The CNC routing of ornaments was simulated with two types of tools and two processing methods (engraving and carving) using CAD-CAM-CAE software and the models were afterward processed on wood panels by CNC router and laser equipment and then visually analysed, concluding which method and tool is suitable for each type of ornament, so to transpose better the original motif on furniture wood surface.
FEM-based investigation on machining forces and temperatures induced during AISI-4140 hard turning
Authors: Tzotzis Anastasios , Efkolidis Nikolaos , Tzetzis Dimitrios , Kyratsis Panagiotis
Published: March 2022

Turning is probably one of the most common machining processes used to manufacture parts for the industrial sector. In order to reduce development times and costs during turning, it is necessary to employ methodologies and techniques that enable the precise prediction of the important parameters that relate to the process. Such a methodology is the implementation of Finite Element Method (FEM). In this work, the 3D modelling of AISI-4140 hard turning with ceramic tooling is being presented by utilizing the DEFORM-3D™ Finite Element Analysis (FEA) software system. Nine tests were conducted according to typical cutting conditions as recommended by tool manufacturers; cutting speed of 80 m/min, 115 m/min and 150 m/min and feed of 0.08 mm/rev, 0.11 mm/rev and 0.14 mm/rev, at a constant depth of cut equal to 0.30 mm. The developed friction forces, heat transfer and contact interface stresses between the tool and the workpiece were approximated with the aid of well-established models to simulate the machining mechanisms. Additionally, a validation of the yielded results for the machining components and the temperature distribution was performed by comparing the numerical results with experimental data. Most of the simulations generated results in agreement with the experimental ones. The agreement percentage exceeds 90% in most tests for the investigated components (machining forces and temperature), confirming both the validity and the accuracy of the model.
Finite element analysis for testing safety-belt anchorages
Authors: Manea A M , Iozsa M D , Stan C , Ioniţă A
Published: March 2022

The passive safety of the vehicle is ensured by designing optimized restraint systems to protect the occupants during the accident. The safety-belts have the role of restraining the occupants of the car on the seat during an impact or in the event of a rollover. Their retention prevents or minimizes the impact between the occupants and the interior components of the passenger compartment. Two simplified models of seat structures are proposed to determine the strength of the safety-belts anchorages. The test of the anchorage for safety-belts of the two seat models is performed in accordance with Regulation no. 14 UNECE. For the two seat models, a three-dimensional resistance structure was made. The 3D models of the seats were inserted in the FEA software. The analysis of the models is done by the finite element method with the Static Structural module of the FEA software. A tensile force is applied during the test on the safety-belts anchorages. The traction force shall be applied in the direction corresponding to the seating position, at an angle of 10°±5° above the horizontal, in a plane parallel to the median longitudinal plane of the vehicle. During the tests the safety-belt anchorages shall withstand the entire period of application of the traction force and the upper safety-belt anchorage shall not be displaced during the test forward of a transverse plane passing through the R point of the seat.
Ground penetrating radar for real time surveying of soil as bioremediation precursor
Authors: Iftimie N , Steigmann R , Dobrescu G S
Published: March 2022

GPR is a non-destructive method based on the emission and reception of electromagnetic waves generated by a bowtie antenna, of 400 MHz, in our case. The soil conductivity influences the propagation of electromagnetic waves, thus any inhomogeneity as water lens, chemical pollution, soil texture, buried objects modify the signal scattered on them and recorded by GPR tools. One of the potential advantages of GPR is that it is able to quickly analyses the presence in the underground of various inhomogeneities without having to come into contact with the ground and measures the time interval between pulse generation and reception, the results being presented in B-scan and linescan representation. Combining and processing the received signals, the results show as a map with emphasized watering regions. This paper presents the results of a case study where it was determined the effectiveness of GPR technology in detecting water content as well as the presence of water holes in airport runway draw. Further investigations will include the use of GPR together with electromagnetic induction method in order to make data fusion and increase the probability of detection.
Desalination by endothermal generators
Authors: Monteiro B , Cavique M
Published: March 2022

Many regions of the planet are under water stress that can create humanitarian disasters. Where available, seawater can undergo a desalination process to produce drinkable water. The desalination processes may use thermal and mechanical energy. Methods based on evaporation and flashing are thermal driven, whether water osmosis uses mechanical energy. An endothermal motor can generate both mechanical and thermal energy. This paper focuses on a Diesel generator able to supply an electrical power of 362 kW. It evaluates the water production of a combined system with a Multi-Effect Evaporator and a Reverse Osmosis system. The Multi-Effect Evaporator uses the thermal energy from the exhaust gases; the Reverse Osmosis uses the generator's electrical power. The generator is typical for marine applications and can be deployed in humanitarian operations. The system can produce 1,011 m3 per day of drinkable water, enough to supply the daily basic needs of a population of about 50,500 persons.
Development of a “Virtual Learning Factory” for learning and applying specific Lean manufacturing methods
Authors: Neacsu G C , Pascu I G , Nitu E L , Ionescu L , Gavriluta A C , Belu N
Published: March 2022

The processes and systems of production and training, influenced by the digital era, are forced to evolve at an accelerated pace to satisfy the need of innovation and digitization. Thus, the development of virtual learning factories within universities, which can adapt to the requirements of innovation and digitalization, is a solution. In this context, the paper presents how to development a virtual learning factory, flexible-reconfigurable to allow easier learning and experimentation of methods, techniques and tools used in Lean manufacturing. To achieve this, specific Lean manufacturing methods will be digitized for integration into the virtual factory, through programming in the Unity platform, using its specific C # language. Thus, at the end of the paper we want to obtain a virtual, mobile and flexible learning factory, which will help the user to understand, learn and experiment easily and in an attractive way the methods and techniques used in Lean manufacturing.
Experimental tests to validate the usage domain for personalised formworks
Authors: Diaconu Raluca , Brindasu Paul Dan
Published: March 2022

Analysing the nowadays tendency for customised products, the personalised formwork is a solution that is worth taking into account. Not only that the concrete mould (due to the composite membrane) can take various shapes, function of the designer’s requirements, but it can be reusable and remodelled at each usage. By using the Product Lifecycle Management (referred as PLM) principles, two directions were analysed: a pushing system without any auxiliary reinforcement of the formwork and a pulling system with additional reinforcement under the formwork membrane. The composite membrane is subjected to multiple tests with different variants. By analysing the resulting values regarding the final shape of the product (concrete element), the proposed solutions were validated by defining the usage domain for each type of personalised formwork.
Hidden surface channel in two-dimensional multilayers
Authors: Seo Youkyung , Kim Soo Yeon , Kim Yeeun , Kim Chulmin , Lee Byung Chul , Park Yoon Hee , Chae Minji , Hong Youjin , Seong Min Kyung , Ko Changhyun , Cresti Alessandro , Theodorou Christoforos , Kim Gyu Tae , Joo Min-Kyu
Published: April 2022

Numerous carrier scatterers, such as atomic defects, fixed oxide charges, impurities, chemical residues, and undesired surface adsorbates, including oxygen and water molecules, strongly degrade the carrier mobility of atomically thin two-dimensional (2D) materials. However, the effect of surface adsorbates and surface oxidation on the carrier density profile along the thickness of 2D multilayers is not well known, particularly for a substantial interruption in the formation of the top-surface channel. Here, we uncover a hidden surface channel in p-type black phosphorus and n-type rhenium disulfide multilayers originating from undesired ambient adsorbates and surface oxides that not only populate hole density (or reduce electron density) but also suppress carrier mobility. The absence of a second peak in the transconductance curve under ambient conditions indicates the disappearance of the top-surface channel inside the 2D multilayers, which is a possible indicator for the cleanliness of the top surface and can be used in gas sensor applications. Moreover, the negligible variation in the drain bias polarity-dependent turn-on voltage for the bottom channel under ambient conditions validates the exclusive contribution of surface adsorbates to the formation of the top channel in 2D multilayers. Our results provide a novel insight into the distinct carrier transport in 2D optoelectronic devices and diverse sensors.
FBDNN: filter banks and deep neural networks for portable and fast brain-computer interfaces
Authors: Bassi Pedro R A S , Attux Romis
Published: March 2022

Objective. To propose novel SSVEP classification methodologies using deep neural networks (DNNs) and improve performances in single-channel and user-independent brain-computer interfaces (BCIs) with small data lengths. Approach. We propose the utilization of filter banks (creating sub-band components of the EEG signal) in conjunction with DNNs. In this context, we created three different models: a recurrent neural network (FBRNN) analyzing the time domain, a 2D convolutional neural network (FBCNN-2D) processing complex spectrum features and a 3D convolutional neural network (FBCNN-3D) analyzing complex spectrograms, which we introduce in this study as possible input for SSVEP classification. We tested our neural networks on three open datasets and conceived them so as not to require calibration from the final user, simulating a user-independent BCI. Results. The DNNs with the filter banks surpassed the accuracy of similar networks without this preprocessing step by considerable margins, and they outperformed common SSVEP classification methods (SVM and FBCCA) by even higher margins. Conclusion and significance. Filter banks allow different types of deep neural networks to more efficiently analyze the harmonic components of SSVEP. Complex spectrograms carry more information than complex spectrum features and the magnitude spectrum, allowing the FBCNN-3D to surpass the other CNNs. The performances obtained in the challenging classification problems indicates a strong potential for the construction of portable, economical, fast and low-latency BCIs.
Resveratrol pretreatment protects neurons from oxygen–glucose deprivation/reoxygenation and ischemic injury through inhibiting ferroptosis
Authors: Zhu Huimin , Huang Jiagui , Chen Yue , Li Xuemei , Wen Jun , Tian Mingfen , Ren Jiangxia , Zhou Li , Yang Qin
Published: March 2022

Ferroptosis, a newly discovered iron-dependent cell death, is involved in brain ischemia–reperfusion injury. Iron scavengers or ferroptosis inhibitors could reduce infarct volume and improve neurological function in mice. Resveratrol has neuroprotective and neurorestorative effects. However, it is unclear whether resveratrol can play a neuroprotective role via inhibiting ferroptosis. Our study showed that resveratrol pretreatment had a similar effect with ferrostatin‑1, which inhibited neuronal ferroptosis-related changes, such as iron overload, damages of oxidation-reduction system, and destruction of mitochondrial structure, after oxygen–glucose deprivation/reoxygenation (OGD/R) and application of ferroptosis inducers. In addition, middle cerebral artery occlusion/reperfusion (MCAO/R) injury in vivo also induced ferroptosis, and resveratrol pretreatment could inhibit ferroptosis and reduce degenerative neurons, cerebral ischemic damage and infarction volume. Our results are the first to indicate that resveratrol pretreatment might inhibit ferroptosis induced by OGD/R and ferroptosis inducers in neurons, and MCAO/R in rats.
Hyperandrogenism diminishes maternal–fetal fatty acid transport by increasing FABP4-mediated placental lipid accumulation
Authors: Gopalakrishnan Kathirvel , Mishra Jay S , Ross Jordan R , Abbott David H , Kumar Sathish
Published: March 2022

Long-chain polyunsaturated fatty acids (LCPUFAs) are critical for fetal brain development. Infants born to preeclamptic mothers or those born growth restricted due to placental insufficiency have reduced LCPUFA and are at higher risk for developing neurodevelopmental disorders. Since plasma levels of testosterone (T) and fatty acid-binding protein 4 (FABP4) are elevated in preeclampsia, we hypothesized that elevated T induces the expression of FABP4 in the placenta leading to compromised transplacental transport of LCPUFAs. Increased maternal T in pregnant rats significantly decreased n-3 and n-6 LCPUFA levels in maternal and fetal circulation, but increased their placental accumulation. Dietary LCPUFAs supplementation in T dams increased LCPUFA levels in the maternal circulation and further augmented placental storage, while failing to increase fetal levels. The placenta in T dams exhibited increased FABP4 mRNA and protein levels. In vitro, T dose-dependently upregulated FABP4 transcription in trophoblasts. Testosterone stimulated androgen receptor (AR) recruitment to the androgen response element and trans-activated FABP4 promoter activity, both of which were abolished by AR antagonist. Testosterone in pregnant rats and cultured trophoblasts significantly reduced transplacental transport of C14-docosahexaenoic acid (DHA) and increased C14-DHA accumulation in the placenta. Importantly, FABP4 overexpression by itself in pregnant rats and trophoblasts increased transplacental transport of C14-DHA with no significant placental accumulation. Testosterone exposure, in contrast, inhibited this FABP4-mediated effect by promoting C14-DHA placental accumulation.
Dam parity structure and body condition during lactation influence piglet growth and gilt sexual maturation through pre-finishing
Authors: Rempel Lea A , Keel Brittney N , Oliver William T , Wells James E , Lents Clay A , Nonneman Dan J , Rohrer Gary A
Published: April 2022

Energy demands during lactation greatly influence sow body condition and piglet performance. We hypothesized that primiparous sows or sows with reduced body condition would produce piglets with reduced growth and delayed sexual maturation. Eight weekly farrowing seasons were used to evaluate sow body condition (post-farrowing, PF and weaning, WN) and piglet growth from 157 dams. Body condition was measured at PF and WN using sow calipers (last rib and hip) and 10th rib ultrasound. Sows were categorized as thin, moderate, or fat by caliper (PF or WN). Individual pig weights were recorded on approximately 1, 10, WN, 45, 100, and 145 d of age. At 100 and 145 d of age, 10th-rib backfat and loin eye area were measured on 567 pigs and first estrus was monitored in 176 gilts reserved for breeding selection beginning at approximately 170 d of age. Sows had similar (P > 0.10) PF last rib caliper measurements but at WN, first parity sows had the smallest caliper measurements compared to other parities (P < 0.05). Parities 1, 2, and 3 sows had similar (P > 0.10) loin eye area at PF; however, at WN first parity sows had the smallest loin eye area (P < 0.05; 38.2 ± 0.63 cm2). Parity 1 sows had the greatest (P < 0.05) reduction of backfat and loin eye area over the lactation period (−2.9 ± 0.31 mm and −2.6 ± 0.49 cm2, respectively). At 1 d of age and WN, piglets from first parity sows weighed the least (P < 0.05) but were the heaviest (P < 0.05) at 100 and 145 d of age. Pigs from first parity litters had larger (P < 0.05) loin eye area at 100 and 145 d of age and greater backfat (P < 0.05) at 145 d of age. Fat sows at WN (last rib or hip) had the lightest (P < 0.05) piglets at 10 d of age and WN. However, at 45 d of age, piglets from fat sows (last rib or hip) were heavier (P < 0.05) than piglets from moderate and thin sows. Tenth rib backfat at 100 and 145 d of age tended (P < 0.10) to be less in pigs reared by thin sows (PF and WN hip). Tenth rib loin eye area was similar among pigs reared by fat, moderate, or thin sows. Gilts developed in litters from fourth parity sows had (P < 0.05) delayed age at puberty in contrast to gilts from first or third parity sows (200.9 ± 4.96 d vs. 189.0 ± 2.29 d and 187.5 ± 2.84 d, respectively). Although progeny body weights were typically less from first parity dams through 45 d of age, these progeny were similar or heavier at 100 and 145 d of age in contrast to progeny from other parities. Furthermore, gilt progeny from first parity dams did not have delayed pubertal attainment.
Out-of-Pocket Costs for Colposcopy Among Commercially Insured Women From 2006 to 2019
Authors: Fendrick A. Mark , Dalton Vanessa K. , Tilea Anca , Malone Anita M. , Moniz Michelle H.
Published: March 2022

(Abstracted from Obstet Gynecol 2022;139:113–115)

Colposcopy is an evidence-based, recommended procedure for women with an abnormal initial cervical cancer screening test result. Cervical cancer screening modalities, including Papanicolaou testing and human papillomavirus testing, are covered by the Affordable Care Act without consumer cost sharing for average-risk, age-eligible women.
Fertility Status Among Long-Term Childhood Acute Lymphoblastic Leukaemia Survivors Enrolled Between 1971 and 1998 in EORTC CLG Studies: Results of the 58 Late Adverse Effects Study
Authors: Rossi Giovanna , Kicinski Michal , Suciu Stefan , Vandecruys Els , Plat Geneviève , Uyttebroeck Anne , Paillard Catherine , Barbati Mélissa , Dresse Marie-Françoise , Simon Pauline , Minckes Odile , Pluchart Claire , Ferster Alina , Freycon Claire , Millot Frederic , van der Werff ten Bosch Jutte , Chantrain Christophe , Paulus Robert , de Rojas Teresa , de Schaetzen Gaetan , Rohrlich Pierre , Benoit Yves , Piette Caroline
Published: March 2022

(Abstracted from Hum Reprod 2022;37:44–53)

Childhood acute lymphoblastic leukemia (ALL) has an expected cure rate of greater than 90%, reflecting a vast improvement in diagnosis and treatment over the last 40 years. Fertility impairment is among the chief concerns of long-term survivors because of possible damage to reproductive organs or hormonal balance stemming from treatment.
Genome-Wide Cell-Free DNA Screening: A Focus on Copy-Number Variants
Authors: Rafalko Jill , Soster Erica , Caldwell Samantha , Almasri Eyad , Westover Thomas , Weinblatt Vivian , Cacheris Philip
Published: March 2022

(Abstracted from Genet Med 2021;23:1847–1853)

In 2015, a study found that traditional cell-free DNA (cfDNA) screening had the capability to detect approximately 70% to 80% of the karyotypic abnormalities identified in fetuses and infants. The remaining 20% to 30% that are missed include clinically relevant findings such as subchromosomal deletions and duplications, rare autosomal aneuploidies, and polyploidy, representing an area of growth for prenatal screening tests, and genome-wide cfDNA screening is now available.
The Natural History of Trisomy 21: Outcome Data From a Large Tertiary Referral Centre
Authors: O'Connor Clare , Moore Rebecca , McParland Peter , Hughes Heather , Cathcart Barbara , Higgins Shane , Mahony Rhona , Carroll Steve , Walsh Jennifer , McAuliffe Fionnuala
Published: March 2022

(Abstracted from Fetal Diagn Ther 2021;48:575–581)

Down syndrome (DS) or trisomy 21 (T21) is characterized as the presence of a third copy of chromosome 21. The rate of DS increases with maternal age, and it is the most common aneuploidy in live-born infants.
Impact of Effortful Word Recognition on Supportive Neural Systems Measured by Alpha and Theta Power
Authors: Ryan David B. , Eckert Mark A. , Sellers Eric W. , Schairer Kim S. , McBee Matthew T. , Jones Marissa R. , Smith Sherri L.
Published: April 2022

Objectives:

The goal of this study was to use theta and alpha electroencephalography (EEG) frequency power and self-report measures to examine performance monitoring, cognitive inhibition, and perceived effort required for speech understanding in noise. It was hypothesized that with a linear increase in word recognition task difficulty, there would be a linear increase in listening effort and word recognition performance would decrease in the challenging conditions. In addition, theta and alpha power would have an inverted U-shape across easy to challenging listening conditions. The inverted U-shape would reflect the neural underpinnings of listening effort that cannot be measured by task performance alone.

Design:

EEG data were collected in 34 normal-hearing adults (18 to 33 years old) during the Words-In-Noise (WIN) test, which was presented in sound field. EEG frequency data were averaged and analyzed at three frontal channels for theta power (4 to 8 Hz), which is thought to reflect performance monitoring, and three parietal channels for alpha power (8 to 12 Hz), which is thought to reflect cognitive inhibition. A ten-point visual analog scale was administered after each WIN signal-to-noise ratio (SNR) condition to capture self-reported required and invested listening effort (RLE and ILE, respectively). The WIN SNR conditions were presented in descending and random order.

Results:

The SNR presentation (descending or random SNR) had a null effect on word recognition performance; however, presentation did have an effect on theta power, alpha power, and ILE. When controlling for presentation, there were significant effects of SNR and presentation on both theta and alpha frequency power. Theta and alpha power had an inverted U-shape as a function of SNR from easy to challenging, with peak power in the moderate SNR conditions. RLE and ILE both significantly increased as task difficulty increased as expected; however, RLE showed a stronger relation to task performance than ILE. Alpha power was a significant predictor of RLE, ILE, and WIN performance when controlling for SNR.

Conclusions:

The elevated theta and alpha power in the easy to moderate SNRs and alpha power predicting self-reported listening effort suggest the activation of supportive neural systems during word recognition that could be considered a marker of listening effort. Moreover, the measures of neural support systems and listening effort were independent from task performance, which is a key element to further understanding the neural bases for listening effort. In the context of the broader literature, these results are consistent with (1) a parietal alpha role in supporting inhibitory control to suppress irrelevant information and (2) a frontal theta role in supporting performance monitoring in difficult listening conditions where speech recognition is feasible.
Fractures of the proximal segments of the pediatric distal radial metaphysis exhibit less angular stability than fractures of the distal segments
Authors: Sato Kotaro , Mimata Yoshikuni , Takahashi Gaku , Murakami Kenya , Numata Norio , Doita Minoru
Published: March 2022

The distal part of the forearm is divided into the physis, metaphysis, diaphyseal metaphyseal junction (DMJ) and diaphysis. The treatment of radial DMJ fractures is challenging because this region has diaphyseal characteristics. We speculated that the stability of metaphyseal fractures could vary depending on their proximity to the DMJ or physis. Our study aimed to investigate the stability of pediatric distal radius fractures in the physis, metaphysis and DMJ. Ninety-five patients were classified into three groups: group D, fracture line located within 1/2 of the width of the radius (WOR) from the physis; group M, fracture line located between 1/2 and 1 WOR from the physis; and group P, fracture line located between 1 and 2 WOR from the physis. We measured sagittal angulation and coronal angulation. A correction loss of less than 9° was defined as a ‘stable reduction’ outcome and one greater than 10° as a ‘loss of reduction’ outcome. The correction losses for sagittal angulation were significantly greater in groups M and P than in group D. The correction losses for coronal angulation were significantly greater in group P than in groups D and M. The incidence of ‘loss of reduction’ outcomes was significantly higher in groups M and P than in group D. The proximal segments of distal radial metaphyseal and DMJ fractures showed less angular stability than distal segments.