bluuebunny/crossref_metadata_2025 huggingface dataset:
An Investigation of the Redox Stability of an Anode-Supported SOFC Stack Using Acoustic Emission Monitoring
Authors: Rangel-Hernandez Victor , de Haart Ute , Fang Qingping , Schäfer Dominik , Thaler Florian , Peters Ralf , Blum Ludger
Published: July 2021

The current interest in solid oxide fuel cells (SOFC) technology lies mainly in its high power generation/conversion efficiency and its low or zero emissions. Their application in stationary power generation systems indicate their maturity to date. However, the stability and performance of the cells or stacks could be affected due to the adverse conditions to which they are exposed. One of the most concerning conditions for Ni-based anode-supported cells (ASC) is when the stack is subjected to unplanned reduction-oxidation (Redox) cycles, which can lead to irreversible damage to the cell. During a Redox cycle, the anode undergoes changes in its volume, due to the oxidation of nickel (Ni) to nickel oxide (NiO), which causes microstructural damages to the anode itself or to the electrolyte or to both. Previous study has shown that the cell performance decreased after redox cycling above 600 °C, mainly based on voltage-current curve or electrochemical impedance measurements. However, there is little information on the application of acoustic emission (AE) techniques in the study of redox cycling. Therefore, the purpose of this work is to investigate the redox process and stability of a SOFC stack through the application of the AE monitoring. The research will include the analysis of the AE signals, the AE cumulative energy as well as an analysis in the frequency domain. This is expected to contribute to the understanding of the redox process inside stack and failure modes of the cell.
Effect of Fuel Depletion on Ni-YSZ Anode Supported Membrane Fuel Cell Under Different Discharge Modes
Authors: Lv Zhe , Huang Xiaoying , Liu Xin
Published: July 2021

Declining performance and service life are important factors restricting SOFC commercial applications. It is necessary to study the influencing factors of material selection, preparation process, operation parameter and failure. During the long-term operation, local gas path failure may lead to insufficient or depletion of fuel gas supply, which may lead to the decline of battery performance or failure directly. During the discharge period, there are two possibilities: gas depletion in a cell unit in stack or in a local region of one cell. In this work, button single cells with Ni-YSZ (anode support)|YSZ (film)|GDC (buffer layer)|LSCF (cathode) structure by mass-producing under industrial conditions were operated with dry hydrogen as fuel. The experiments of fuel gas depletion were carried out by constant current and constant voltage discharge modes to simulate single cell unit failure in series stack and local region failure of one cell. The results show that during constant current discharge, the terminal voltage decreased rapidly and even appeared negative voltage after cutting off the H2 supply. When the H2 was refueled, voltage could rise quickly or even exceed the initial value. However, as the hydrogen was cut off and the constant current was maintained, the performance of the single cell decreased significantly, and the open circuit voltage and maximum power density decreased sharply, which was due to the damage of the cell caused by the anode Ni oxidation-reduction cycles, and cracks appeared on the electrolyte membrane. By contrast, no matter how long the fuel supply was cut off, the single cell performance in constant voltage discharging mode didn’t decline significantly, which indicates that maintaining a reasonable cell terminal voltage can avoid the Ni oxidation in anode caused by fuel depletion. Finally, we conclude that the long time fuel depletion of the cell unit may directly destroy the cell and affect the stack life, while the local fuel depletion of a certain cell will not cause its damage.

References

1. M. H. Tran, B. J. Park, H. H. Yoon, J. Colloid Interface Sci., 578, 641-649 (2020).

2. N. Wongsawatgul, S. Chaianansutcharit, K. Yamamoto, et al, Ceram., 3 (1), 114-126 (2020).

3. H. J. Cho, G. M. Choi, Solid State Ion, 180, 792-795 (2009).

4. Z. R. Wang, J. Q. Qian, S. R. Wang, et al, Solid State Ion, 179, 1593-1596 (2008).

Figure 1
Investigating Effects of Operational Parameters on the Rate of Electrochemical Cleaning of Chromium Deposits on Strontium-Doped Lanthanum Manganite Cathodes in Solid Oxide Fuel Cells
Authors: Sugimoto Michelle , Zhu Zhikuan , Gopalan Srikanth , Basu Soumendra , Pal Uday
Published: July 2021

Chromium poisoning of the cathode remains a significant obstacle to the long-term performance of solid oxide fuel cells. Previously, a quick, easy method was introduced that requires no material modifications, major thermal cycling, nor exposes the cell to any species it does not already encounter during operation. The method, electrochemical cleaning, reverses the electrochemical deposition reaction of chromium-containing species by applying a mild anodic bias. Chromium vapor species are formed, freeing active sites in the cathode. The method has been shown to completely recover cell performance via this current-voltage technique.

The present work investigates the mechanism of electrochemical cleaning by assessing the effect of various operating parameters on the rate of chromium removal. Using a design of experiments method, eight cells were poisoned and then cleaned using differing combinations of the following cleaning parameters: cell temperature, air humidity, anodic current density, and fuel humidity. Regression analysis of two comparative metrics, cell performance via current voltage curves and post-test chromium content determined via Energy Dispersive Spectroscopy, demonstrated that cell temperature has the highest effect on the rate of chromium removal, followed by air humidity. A refined parameter space for future study is proposed for further optimization of the parameters. Previously, the electrochemical cleaning method was shown to be effective in the removal of Cr2O3 deposited species, but not Cr-Mn spinel deposits. The effects of operating parameters on the removal of the two different types of Cr deposits is discussed. An additional process for the removal of Cr-Mn spinel is demonstrated, which again makes use of the cell operating parameters. Together, the two methods present a facile, periodic process to greatly extend solid oxide fuel cell lifetime.
Determination of Factors Governing Degradation of Anode-Supported Solid Oxide Fuel Cells as Influenced by Current Density and Humidity
Authors: Budiman Riyan Achmad , Bagarinao Katherine Develos , Ishiyama Tomohiro , Yamaguchi Toshiaki , Kishimoto Haruo , Yamaji Katsuhiko
Published: July 2021

Anode-supported solid oxide fuel cells (SOFCs) offer the advantage of thinner electrolyte membranes which greatly reduce the ohmic loss and enables lower operating temperature and higher performance. However, a significant contribution to the polarization resistance is attributed to the anode, as the thickest component in the cell, which can influence the distribution of hydrogen partial pressure, p(H2) and water vapor pressure, p(H2O) especially when combined with current density to achieve high fuel utilization. To understand the degradation mechanism in long-term operation of a commonly used anode material, Ni/YSZ, commercial anode-supported cells were evaluated under varied current density (up to 1 A/cm2) and humidity (1-60%) using electrochemical impedance spectroscopy. The impedance spectra were analyzed using distribution of relaxation times (DRT) method to separate the resistance contribution from each component of the cell. The Ni/YSZ anode resistance was observed to increase with higher current density and humidity, suggesting that the degradation may be correlated to microstructural factors such as Ni agglomeration leading to reduced Ni interparticle contact, causing the increase in anode resistance. In addition, analysis using the 1-D transmission line model to determine the effective reaction length (ERL) of Ni/YSZ anode, revealed that the ERL moves further from the TPB with increasing degradation. Details of the post-test microstructural characterization of the cells will be discussed during the presentation.
Commercialization of the Ceres Power SteelCell® Technology: Latest Update
Authors: Leah Robert , Bone Adam , Selcuk Ahmet , Lankin Mike , Rahman Mahfujur , Clare Andy , Reade Gavin , Felix Florence , De Vero Jeffrey , Wang XIn , Mukerjee Subhasish , Selby Mark
Published: July 2021

Ceres Power continues to acquire commercial partners for its low-temperature metal supported SteelCell® SOC technology based predominantly around the use of ceria. This unique design architecture allows for a robust, low cost, subsidy free fuel cell product, whilst retaining the advantages of fuel flexibility, high efficiency and low degradation.

Over the last year, significant commercial developments have taken place, rapidly progressing genuine mass-market adoption of SteelCell® technology for power generation. Two major OEM partners, Robert Bosch GmbH in Germany and Doosan Fuel Cell in South Korea now have licenses to manufacture SteelCell® cells and stacks with a full technology transfer from Ceres, with a commitment to volume manufacturing. Doosan is initially building a 50MW/y manufacturing plant with potential to extend that further in future. This complements Ceres’ own manufacturing facility in Redhill, UK which is fully operational with an expandable capacity of 2MW/y to meet demand from other customer demonstration programs.

Other active customer programs include the successful ongoing commercial launch of a 4.2kWe CHP system by Miura in Japan and the development of a 30kWe range extender for electric buses by Weichai Power in China.

Another significant commercial development is Ceres Power agreeing a strategic partnership with AVL in Austria to combine engineering expertise and knowhow in fuel cell system development and conduct joint R&D, which will enable the incorporation of SteelCell® technology into new applications. The first agreement has already been signed with an unnamed customer.

As part of a drive to broaden the applicability of SteelCell® technology and play a larger part in the rapidly developing green hydrogen economy, a major program has been initiated to evaluate and develop SteelCell® technology for steam electrolysis and the potential production of E-fuels.

All of these developments are rapidly bringing about the full commercialization of SOC technology as a significant contributor to the evolving net zero energy sector.
Assessing the Performance and Degradation of Metal Supported SOFCs Operating with Natural Gas
Authors: Welander Martha M , Tucker Mike C
Published: July 2021

High operating temperatures endow SOFCs with many advantages including fuel flexibility and high conversion efficiencies, distinguishing them from many other types of fuel cells. In order to leverage this role SOFCs must be able to operate well with a variety of fuels including H2, CH4, natural gas, syngas, and higher molecular weight hydrocarbons. This requirement necessitates keeping the SOFC anodes clear from excessive carbon deposition or “coking” when exposed to hydrocarbon fuels. Standard SOFC anodes composed of a Ni-YSZ cermet are highly susceptible to coking which can be detrimental to overall cell performance as it can block catalytic sites and impede gas transport. One way to mitigate this effect is to introduce steam into the fuel feed to remove carbon via oxidation. However, steam also risks oxidizing the catalytically active Ni metal resulting in volume changes that may damage the fragile electrode microstructure, requiring material or mechanical solutions to improve overall cell resilience. LBNL has developed metal supported SOFCs (MS-SOFCs) with unique symmetrical architecture and infiltrated catalysts with numerous advantages over conventional cells including low cost, mechanical ruggedness, quick start-up capability, and excellent tolerance to redox cycling and thermal cycling under standard H2 conditions. The high mechanical stability of LBNL’s MS-SOFCs suggest that they may be well suited for long-term hydrocarbon operation, even when high levels of steam are present in the fuel stream.

In this work, the use of LBNL’s MS-SOFCs are extended to natural gas. As the least carbon-intensive fossil fuel, natural gas has the potential to serve as a bridging fuel, facilitating the transition into a low carbon energy economy. The durability of the MS-SOFCs under natural gas and reformate fuels have been evaluated at 700 °C as well as the resilience toward thermal cycling under equivalent fuel conditions to demonstrate the feasibility of using the cells in applications that require rapid start/stop cycles (with ramp rates <15 minutes). These experiments suggest that cell exposed to natural gas reformates operate and degrade in a similar manner to cells operating with pure H2 and have high tolerance to repeated thermal cycling. Cells operating with natural gas under internal reformate conditions experience faster degradation rates and the ability to improve the performance of these cells with a high entropy alloy catalyst will be discussed. Ongoing experiments will examine durability of the MS-SOFCs to reformate and natural gas fuels with sulfur contamination in order to determine the effect of carbon species present in the fuel stream on sulfur reactions at the electrode. This talk will give an overview of the current status of LBNL’s MS-SOFC technology operating with natural gas fuel and reformates, the effect of sulfur poisoning, resilience to thermal cycling, as well as determine future improvements required for improved cell performance and commercialization.
Electrical Energy Storage Using Hydrogen Storage Alloy Coupled Proton-Conducting Reversible Solid Oxide Cell
Authors: Chen YanBo , Shi Yixiang , Cai Ningsheng
Published: July 2021

Proton-conducting reversible solid oxide cell (RSOC) can efficiently store intermittent renewable energy in the form of hydrogen. The cell can operate in either SOFC mode or SOEC mode and achieve efficient and low cost energy storage. The RSOC needs a hydrogen storage equipment to reach enough energy storage capacity.

In this study, a hydrogen storage alloy coupled proton-conducting reversible solid oxide cell is developed and functions as rechargeable battery. Experiments are performed at 500-650℃ using a Ni-BCZY/BCZY(BaCe0.5Zr0.4Y0.1O3)/LSM-BCZI micro-tubular cell and Zr-based hydrogen storage alloy. The hydrogen production and electrochemical performance are studied with different operating conditions and amount of hydrogen storage alloy. The current density ranges from -970A/m2 to -1230A/m2 for the SOEC mode, and from 960 A/m2 to 1300 A/m2 for the SOFC mode at a polarization voltage of 0.1 V with different gas compositions and temperatures. The hydrogen storage ranges from 0.4wt% to 1.4wt%.

To further optimize the hydrogen storage alloy coupled RSOC, a muti-scale and muti-physics two-dimensional (2D) micro-tubular RSOC model is developed. This model couples the electrochemical reaction, charge transfer, mass transfer, momentum transfer, heat transfer as well as the parameters of microscale porous electrodes and the hydrogen alloy. The model is validated by the experimental data obtained above. The simulation results shows that the cell’s capacity and round trip efficiency are dependent on the amount of hydrogen storage alloy utilized. The energy capacity increases while the roundtrip efficiency decreases with increasing alloy utilization. A practical strategy to operate the new battery is to maintain a low alloy utilization and get a required storage capacity as well as a high efficiency. The model is demonstrated an useful tool for the design and optimization of the hydrogen storage alloy coupled RSOC.
Epigenetic modifications underlie the differential adipogenic potential of preadipocytes derived from human subcutaneous fat tissue
Authors: Kubota Yoshitaka , Nagano Hidekazu , Kosaka Kentaro , Ogata Hideyuki , Nakayama Akitoshi , Yokoyama Masataka , Murata Kazutaka , Akita Shinsuke , Kuriyama Motone , Furuyama Nobutaka , Kuroda Masayuki , Tanaka Tomoaki , Mitsukawa Nobuyuki
Published: July 2021

Ceiling culture-derived preadipocytes (ccdPAs) and adipose-derived stem cells (ASCs) can be harvested from human subcutaneous fat tissue using the specific gravity method. Both cell types possess a similar spindle shape without lipid droplets. We previously reported that ccdPAs have a higher adipogenic potential than ASCs, even after a 7-wk culture. We performed a genome-wide epigenetic analysis to examine the mechanisms contributing to the adipogenic potential differences between ccdPAs and ASCs. Methylation analysis of cytosines followed by guanine (CpG) using a 450-K BeadChip was performed on human ccdPAs and ASCs isolated from three metabolically healthy females. Chromatin immunoprecipitation sequencing was performed to evaluate trimethylation at lysine 4 of histone 3 (H3K4me3). Unsupervised machine learning using t-distributed stochastic neighbor embedding to interpret 450,000-dimensional methylation assay data showed that the cells were divided into ASC and ccdPA groups. In Kyoto Encyclopedia of Genes and Genomes pathway analysis of 1,543 genes with differential promoter CpG methylation, the peroxisome proliferator-activated receptor (PPAR) and adipocytokine signaling pathways ranked in the top 10 pathways. In the PPARγ gene, H3K4me3 peak levels were higher in ccdPAs than in ASCs, whereas promoter CpG methylation levels were significantly lower in ccdPAs than in ASCs. Similar differences in promoter CpG methylation were also seen in the fatty acid-binding protein 4 and leptin genes. In conclusion, we analyzed the epigenetic status of adipogenesis-related genes as a potential mechanism underlying the differences in adipogenic differentiation capability between ASCs and ccdPAs.
From pulmonary fibrosis to progressive pulmonary fibrosis: a lethal pathobiological jump
Authors: Selman Moisés , Pardo Annie
Published: July 2021

The month of September is Pulmonary Fibrosis Awareness Month. In this context, we would like to highlight the concept of progressive pulmonary fibrosis, a common denominator/phenotype of many interstitial lung diseases other than idiopathic pulmonary fibrosis, leading to clinical deterioration, decreased quality of life, and high mortality.
Role of the cardiovascular system in ammonia excretion in early life stages of zebrafish (Danio rerio)
Authors: Wang Y. , Pasparakis C. , Grosell M.
Published: July 2021

The purpose of this study was to investigate if the cardiovascular system is important for ammonia excretion in the early life stages of zebrafish. Morpholino knockdowns of cardiac troponin T (TNNT2) or vascular endothelial growth factor A (VEGFA) provided morphants with nonfunctional circulation. At the embryonic stage [30–36 h postfertilization (hpf)], ammonia excretion was not constrained by a lack of cardiovascular function. At 2 days postfertilization (dpf) and 4 dpf, morpholino knockdowns of TNNT2 or VEGFA significantly reduced ammonia excretion in all morphants. Expression of rhag, rhbg, and rhcgb showed no significant changes but the mRNA levels of the urea transporter ( ut) were upregulated in the 4 dpf morphants. Taken together, rhag, rhbg, rhcgb, and ut gene expression and an unchanged tissue ammonia concentration but an increased tissue urea concentration, suggest that impaired ammonia excretion led to increased urea synthesis. However, in larvae anesthetized with tricaine or clove oil, ammonia excretion was not reduced in the 4 dpf morphants compared with controls. Furthermore, oxygen consumption was reduced in morphants regardless of anesthesia. These results suggest that cardiovascular function is not directly involved in ammonia excretion, but rather reduced activity and external convection may explain reduced ammonia excretion and compensatory urea accumulation in morphants with reduced cardiovascular function.
Postnatal development alters functional compartmentalization of myosin light chain kinase in ovine carotid arteries
Authors: Sorensen Dane W. , Injeti Elisha R. , Mejia-Aguilar Luisa , Williams James M. , Pearce William J.
Published: July 2021

The rate-limiting enzyme for vascular contraction, myosin light chain kinase (MLCK), phosphorylates regulatory myosin light chain (MLC20) at rates that appear faster despite lower MLCK abundance in fetal compared with adult arteries. This study explores the hypothesis that greater apparent tissue activity of MLCK in fetal arteries is due to age-dependent differences in intracellular distribution of MLCK in relation to MLC20. Under optimal conditions, common carotid artery homogenates from nonpregnant adult female sheep and near-term fetuses exhibited similar values of Vmax and Km for MLCK. A custom-designed, computer-controlled apparatus enabled electrical stimulation and high-speed freezing of arterial segments at exactly 0, 1, 2, and 3 s, calculation of in situ rates of MLC20 phosphorylation, and measurement of time-dependent colocalization between MLCK and MLC20. The in situ rate of MLC20 phosphorylation divided by total MLCK abundance averaged to values 147% greater in fetal (1.06 ± 0.28) than adult (0.43 ± 0.08) arteries, which corresponded, respectively, to 43 ± 10% and 31 ± 3% of the Vmax values measured in homogenates. Confocal colocalization analysis revealed in fetal and adult arteries that 33 ± 6% and 20 ± 5% of total MLCK colocalized with pMLC20, and that MLCK activation was greater in periluminal than periadventitial regions over the time course of electrical stimulation in both age groups. Together, these results demonstrate that the catalytic activity of MLCK is similar in fetal and adult arteries, but that the fraction of total MLCK in the functional compartment involved in contraction is significantly greater in fetal than adult arteries.
Prepatellar Bursitis with Abscess due to Corynebacterium ulcerans
Authors: Patil Sachin M. , Beck Phillip Paul , Nelson Taylor B. , Acevedo Andres Bran , Roland William
Published: July 2021

Corynebacteria are ubiquitous and reside as skin and mucosa commensals in animals. They are considered contaminants in clinical specimens, but significant clinical data points to their virulence and pathogenic potential over the last two decades. Corynebacteria can cause both community-acquired and nosocomial infections. Corynebacterium diphtheriae (C. diphtheriae) responsible for diphtheria has declined over the previous two decades with an increase in a similar clinical syndrome by Corynebacterium ulcerans (C. ulcerans) in Europe. As per recent studies, C. ulcerans shares similar virulence factors with C. diphtheriae. C. ulcerans has been implicated in airway infections, skin and soft tissue infections, lymphadenitis, wound infections, and rarely necrotizing fasciitis. Pet or farm animals have been the source of these infections to humans, as per recent reports. Strains can be either toxigenic or nontoxigenic. Due to recent advances, methods to characterize strains have become easier with mass spectrometry. Antimicrobial susceptibility testing is a must for definite treatment as C. ulcerans can be resistant to first-line antibiotic therapy. If resources are available, it is prudent to find if there is any toxin production. Here, we describe a rural farmer in central Missouri presenting with acute-onset right knee pain diagnosed with right prepatellar bursitis with abscess due to C. ulcerans infection. He recovered with surgical debridement and antimicrobial therapy. This is the first case of C. ulcerans causing prepatellar bursitis with an abscess as per medical literature review.
Evaluation of the Performance of Conventional Water‐Based Mud Characteristics by Applying Zinc Oxide and Silica Dioxide Nanoparticle Materials for a Selected Well in the Kurdistan/Iraq Oil Field
Authors: AlBajalan Ahmed R. , Haias Hunar K.
Published: July 2021

Nanomaterials have gained a wide interest in the oil and gas industry due to their immense applicability. Nanomaterials are being used to formulate a new generation of drilling mud known as Nanomud or Smart mud, where it has the ability to improve mud properties and eliminate borehole problems. Using nanoparticles as an additive agent in conventional drilling mud can lead to a more efficient drilling process in troublesome formations. In this study, several conventional water‐based muds from a selected well drilled in the Kurdistan/Iraq oil field have been prepared. Then, nanodrilling muds were formulated by dispersing SiO2 and ZnO nanoparticles in concentrations ranging from 0.25 to 1 wt.% to conventional water‐based mud (WBM). This study aims to evaluate and compare the performance of conventional water‐based muds after adding SiO2 and ZnO nanoparticles. This evaluation was performed by carrying out a series of laboratory experiments to determine the rheological and mud filtrate properties. The results demonstrated that nanomuds improved the rheological behaviors and provided better filtration control compared to conventional drilling muds. However, there was little or no impact of the nanomaterials on the mud density for all mud systems.
A Medical Image Registration Method Based on Progressive Images
Authors: Zheng Qian , Wang Qiang , Ba Xiaojuan , Liu Shan , Nan Jiaofen , Zhang Shizheng
Published: July 2021

Background. Medical image registration is an essential task for medical image analysis in various applications. In this work, we develop a coarse-to-fine medical image registration method based on progressive images and SURF algorithm (PI-SURF) for higher registration accuracy. Methods. As a first step, the reference image and the floating image are fused to generate multiple progressive images. Thereafter, the floating image and progressive image are registered to get the coarse registration result based on the SURF algorithm. For further improvement, the coarse registration result and the reference image are registered to perform fine image registration. The appropriate progressive image has been investigated by experiments. The mutual information (MI), normal mutual information (NMI), normalized correlation coefficient (NCC), and mean square difference (MSD) similarity metrics are used to demonstrate the potential of the PI-SURF method. Results. For the unimodal and multimodal registration, the PI-SURF method achieves the best results compared with the mutual information method, Demons method, Demons+B-spline method, and SURF method. The MI, NMI, and NCC of PI-SURF are improved by 15.5%, 1.31%, and 7.3%, respectively, while MSD decreased by 13.2% for the multimodal registration compared with the optimal result of the state-of-the-art methods. Conclusions. The extensive experiments show that the proposed PI-SURF method achieves higher quality of registration.
Integration of Global and Local Features for Specular Reflection Inpainting in Colposcopic Images
Authors: Wang Xiaoxia , Li Ping , Lv Yuchun , Xue Huifeng , Xu Tianxiang , Du Yongzhao , Liu Peizhong
Published: July 2021

Objective. To explore an inpainting method that can balance texture details and visual observability to eliminate the specular reflection (SR) regions in the colposcopic image, thus improving the accuracy of clinical diagnosis for cervical cancer. Methods. (1) To ensure smoothness, Gaussian Blur and filling methods are applied to the global image. (2) Striving to preserve the anatomical texture details of the colposcopic image as much as possible, the exemplar-based method is applied to local blocks. (3) The colposcopic images inpainted in the previous two steps are integrated, so that important information of non-SR regions is preserved based on eliminating SR regions. Results. In the subjective visual assessment of inpainting results, the average of 3.55 ranks first in the five comparison sets. As to the clinical test, comparing the diagnosis results of 6 physicians before and after eliminating SR regions, the average accuracy of two kinds of classifications increased by 1.44% and 2.03%, respectively. Conclusions. This method can effectively eliminate the SR regions in the colposcopy image and present a satisfactory visual effect. Significance. As a preprocessing method for computer-aided diagnosis systems, it can also improve physicians’ accuracy in clinical diagnosis.
Central Extension of Left Alternative Algebras and the Second Cohomology Group
Authors: Boulmane Said
Published: July 2021

The purpose of this paper is to prove that the second cohomology group

H

2

A
,
F

of a left alternative algebra

A

over an algebraically closed field

F

of characteristic 0 can be interpreted as the set of equivalent classes of one-dimensional central extensions of

A

.
Unsteady Aerodynamic Characteristics of Antenna Rotating in Different Elevation Angles
Authors: Zhang Yanqi , Zhang Zhaoming
Published: July 2021

The aerodynamic characteristics of radar antennas should be considered in computing their wind resistance and designing pedestal servo systems. In this paper, the aerodynamic characteristics of a flat plate antenna with azimuthal rotation are explored using a wind tunnel, and the effects of the antenna elevation angle and reduced frequency on the aerodynamic coefficients are analyzed. The corresponding results of numerical simulation are given to compare with the experimental results. The variation of aerodynamic coefficients with respect to the azimuth angle is found to depend on the reduced frequency and the antenna elevation angle. When the increase in antenna elevation angle is slight, the mean and root mean square values of the aerodynamic coefficients are not monotonic with respect to increases in elevation angle and may increase at individual elevation angles. When the elevation angle increases significantly, the mean, maximum, and root mean square values of the aerodynamic coefficients all significantly decrease. The simulation results are in good agreement with the experimental results, which verify the feasibility of using unsteady numerical simulations to obtain the flow field structure when the antenna is rotating. This approach allows the influence mechanism of the elevation angle change on the aerodynamic characteristics of the rotating antenna to be identified.
Auricular Point Acupressure Combined with Compound Lidocaine Cream to Manage Arteriovenous Fistula Puncture Pain: A Multicenter Randomized Controlled Trial
Authors: Liu Xiaohui , Wei Wei , Wu Yaqi , Jiang Xiao , Liu Xueqin , Zhang Ying , Yeh Chao Hsing , Zhang Yuejuan
Published: July 2021

Background. Arteriovenous fistula (AVF) puncture pain is an inevitable problem for maintenance hemodialysis (MHD) patients and may seriously endanger the physical and mental health of patients with MHD. Studies have shown that drug or nondrug measures can reduce AVF puncture pain, but much improvement is needed. When combined with compound lidocaine cream (CLC) in the treatment of AVF puncture pain, auricular point acupressure (APA)—a therapeutic method in which specific points on the auricle of the outer ear are stimulated to treat various disorders of the body—and the therapeutic value and synergistic effects of auriculotherapy merit further investigation. Methods. 120 MHD patients were recruited at blood purification centers in three hospitals between January 2016 and April 2019. After completion of the baseline survey, all patients were randomly divided by the envelope method into a control group, APA group, CLC group, and APA combined with CLC, with 30 subjects per group. The numerical rating scale (NRS) of pain was used to measure the pain before intervention and 1, 4, and 8 weeks after intervention. The State-Trait Anxiety Inventory (STAI), General Comfort Questionnaire (GCQ), blood pressure, and heart rates were obtained before and after the intervention. Results. Pain, anxiety, comfort, blood pressure (BP), and heart rates (HR) of the three groups were better than those of the control group; the difference was statistically significant (

P
<
0.05

). In addition, the APA combined with CLC group was better than the APA group and CLC group, respectively, in those outcomes (

P
<
0.05

). Conclusion. Both APA and CLC can effectively relieve AVF puncture pain, and the combined application has more outstanding effects.
miRNA‐146a Mimic Inhibits NOX4/P38 Signalling to Ameliorate Mouse Myocardial Ischaemia Reperfusion (I/R) Injury
Authors: Xiao Lili , Gu Yulei , Ren Gaofei , Chen Linlin , Liu Liming , Wang Xiaofang , Gao Lu
Published: July 2021

Evidence suggests that miR‐146a is implicated in the pathogenesis of cardiovascular diseases; however, the role of miR‐146a in myocardial ischaemia reperfusion (I/R) injury is unclear. The aim of this study was to explore the functional role of miR‐146a in myocardial ischaemia reperfusion injury and the underlying mechanism. C57BL/6J mice were subjected to 45 min of ischaemia and 1 week of reperfusion to establish a myocardial I/R injury model. A miR‐146a mimic (0.5 mg/kg) was administered intravenously at the beginning of the ischaemia process. Neonatal rat cardiomyocytes were also subjected to hypoxia/reperfusion (H/R). Cells were treated with the miR‐146a mimic or antagonist. As a result, the miR‐146a mimic attenuated H/R‐induced cardiomyocyte injury, as evidenced by increased cell viability and reduced lactate dehydrogenase (LDH) levels. In addition, the miR‐146a mimic inhibited oxidative stress in cells suffering from H/R injury. Moreover, the miR‐146a antagonist exerted adverse effects in vitro. In mice with myocardial I/R injury, the miR‐146a mimic preserved cardiac function and reduced the infarction area and fibrosis. Moreover, the miR‐146a mimic decreased the inflammatory response and reactive oxygen species (ROS) accumulation in mouse hearts. Mechanistically, we found that miR‐146a directly regulated the transcription of NOX4, which subsequently affected P38 signalling in cardiomyocytes. When we knocked down NOX4, the effects of the miR‐146a antagonist in worsening the cell condition were counteracted in in vitro experiments. Taken together, the results suggest that miR‐146a protects against myocardial ischaemia reperfusion injury by inhibiting NOX4 signalling. The miR‐146a mimic may become a potential therapeutic approach for patients with myocardial ischaemia reperfusion.
A Solution of the Inverse Kinematics Problem for a 7-Degrees-of-Freedom Serial Redundant Manipulator Using Gröbner Bases Theory
Authors: Ricardo Xavier da Silva Sérgio , Schnitman Leizer , Cesca Filho Vitalino
Published: July 2021

This article presents a solution of the inverse kinematics problem of 7-degrees-of-freedom serial redundant manipulators. A 7-degrees-of-freedom (7-DoF) redundant manipulator can avoid obstacles and thus improve operational performance. However, its inverse kinematics is difficult to solve since it has one more DoF than that necessary for reaching the whole workspace, which causes infinite solutions. In this article, Gröbner bases theory is proposed to solve the inverse kinematics. First, the Denavit–Hartenberg model for the manipulator is established. Second, different joint configurations are obtained using Gröbner bases theory. All solutions are confirmed with the aid of algebraic computing software, confirming that this method is accurate and easy to be implemented.
Computed Tomography Images under Optimized Iterative Reconstruction Algorithm for Blood Flow Field Characteristics in Cerebral Aneurysm before and after Stent Implantation
Authors: Lin Changkun , Huang Chuizhi , Chen Yan , Jia Nailong , Huang Jinghui , Fu Qimao
Published: July 2021

In order to study the analysis of blood flow field characteristics of cerebral aneurysm patients before and after stent implantation based on CT images of ART-TV-PI, this paper firstly improved the ART-TV algorithm of algebraic reconstruction technology and obtained the ART-TV-PI algorithm, which was compared with the ART algorithm and ART-TV algorithm. Afterwards, the CT images based on the above three algorithms were used to analyze the changes of average blood flow velocity, average wall pressure, average wall deformation, and average shear force of 48 cases of cerebral aneurysm patients before and after stent implantation. The results showed that the mean square error and radiation dose of the ART-TV-PI algorithm (0.00012 and 1.65 mSv) were significantly lower than those of the ART algorithm (0.0031 and 3.09 mSv) and ART-TV algorithm (0.00082 and 2.52 mSv), and the signal-to-noise ratio (23.94) was significantly higher than those of the ART algorithm (11.32) and ART-TV algorithm (16.89), with statistically significant differences (

P
<
0.05

). The differences of mean blood flow velocity, mean wall pressure, mean wall deformation, and mean shear force before and after stent implantation among the three algorithms were not statistically significant (

P
>
0.05

), and the average index of the ART-TV-PI algorithm was the highest. Under the ART-TV-PI algorithm, the mean blood flow velocity (0.044 m/s), the mean wall pressure (71.7 Pa), the mean wall deformation (0.057 mm), and the mean shear force (889 Pa) after stent implantation were significantly lower than those before stent implantation (0.165 m/s, 160.8 Pa, 0.721 mm, and 2690 Pa), with average decreases of 73.3%, 55.4%, 92.1%, and 64.3%, respectively, and the differences were statistically significant (

P
<
0.05

). In conclusion, the images reconstructed by the ART-TV-PI algorithm have good image quality, which provides great convenience for surgical examination of cerebral aneurysm stent implantation and is worthy of clinical application.
Successful Response of Pembrolizumab Rechallenge after Radiotherapy for a Patient with Bladder Cancer of Nonresponse of Pembrolizumab First Challenge
Authors: Ikeda Taro , Hasegawa Go , Kawaguchi Gen , Ikeda Yohei , Hara Noboru , Nishiyama Tsutomu
Published: July 2021

We report a patient with advanced bladder cancer in which the primary lesion and metastatic site disappeared following the pembrolizumab therapy rechallenge after radiotherapy for bladder cancer lesion of nonresponse of pembrolizumab first challenge. A 76-year-old man with advanced bladder cancer received three courses of the chemotherapy with gemcitabine and cisplatin combination; however, the chemotherapy was stopped because of adverse events. The patient started pembrolizumab therapy; however, the effect was not observed. Radiation therapy was given to the primary lesion and pelvic lymph node metastases for the purpose of local control of the lesions. Because the primary lesion was regrowth and para-aortic lymph node metastasis appeared, pembrolizumab therapy was resumed. Thereafter, the primary lesion and metastatic site disappeared.
Experimental and Modeling Studies of Stress Wave Propagation and Energy Dissipation Mechanism in Layered Composite Structures
Authors: Zou Youchun , Xiong Chao , Yin Junhui , Deng Huiyong , Cui Kaibo , Zhang Sa
Published: July 2021

Four composite structures (SiC/UHMWPE/TC4, SiC/TC4/UHMWPE, SiC/UHMWPE/MR/TC4, and SiC/TC4/MR/UHMWPE) were prepared using silicon carbide (SiC) ceramics, ultrahigh molecular weight polyethylene (UHMWPE), titanium alloy (TC4), and metal rubber (MR). The transmitted waves, failure forms, stress wave propagations, and energy dissipations of the composite structures were studied through Split Hopkinson Pressure Bar (SHPB) tests and numerical simulations. The results show that MR in composite structures can delay, attenuate, and smooth the stress wave, thereby reducing SiC damage. UHMWPE on the back of SiC provides cushioning for SiC, while TC4 on the back of SiC aggravates the damage of SiC. The composite structures with MR mainly dissipate the impact energy by reflecting energy, and the energy dissipation performance is better than that of composite structures without MR. A comprehensive comparison of transmitted waves, damage forms, stress wave propagations, and energy dissipations of the four composite structures shows that SiC/UHMWPE/MR/TC4 structure has the best impact resistance. Increasing the thickness of MR in the composite structures can improve the impact resistance, but there are also stress concentration and interface tensile stress.
The Effect of Piezoelectric Fiber Rosette Configurations on Lamb Wave Direction Detection for Damage Localization
Authors: Jiang Shuai , Shen Yiping , Wang Songlai , Peng Yanfeng , Liu Yi
Published: July 2021

Piezoelectric fiber rosettes respond to the directivity characteristics of Lamb waves, and therefore, are useful in detecting the Lamb wave propagation direction. Considering material damage as a secondary wave source, two piezoelectric fiber rosettes are arranged to measure the scattered wave propagation directions for damage localization. The influences of various rosette configurations, i.e., 45°‐rectangular, 135°‐rectangular, 60°‐delta, and 120°‐delta, on the estimation accuracy of the propagation direction are investigated in this paper. The response of the piezoelectric fiber to the A0 mode Lamb wave under narrowband tone‐burst excitation is theoretically derived. Experimental tests and piezoelectric coupling simulations are performed to obtain the Lamb wave signal of each fiber. The matching pursuit (MP) algorithm is applied to extract the weak damage‐related wave packet by using Hann‐windowed narrowband excitation as an atom. The Lamb wave propagation directions are estimated based on the error function. The accuracies of the directions with 4 types of rosette configurations are compared, and their error sources are discussed. The results show that the accuracy of the 135°‐rectangular configuration is relatively satisfactory, and the errors depend on the size and location of each fiber in the rosette. The proposed damage localization method is validated by experimental tests. The predicted locations are close to the actual damage location. The research results are significant for piezoelectric fiber rosette design and optimization and damage location without wave speed or time‐of‐flight information in complex or irregular structures.
Associations between Gestational Diabetes and Anxiety or Depression: A Systematic Review
Authors: OuYang Hong , Chen Bo , Abdulrahman Al-Mureish , Li Ling , Wu Na
Published: July 2021

Gestational diabetes mellitus (GDM) pregnant women are under more psychological stress than normal pregnant women. With the deepening of the study of gestational diabetes mellitus, research has shown that anxiety and depression are also an important cause of gestational diabetes mellitus. Anxiety and depression can cause imbalances in the hormone levels in the body, which has a serious impact on the pregnancy outcome and blood glucose control of pregnant women with GDM. Therefore, the main purpose of this paper is to provide a systematic review of the association between anxiety, depression, and GDM, as well as the adverse effects on pregnant women with GDM. To this end, we searched the PubMed, CNKI, Embase, Cochrane Library, Wanfang, and Weipu databases. Studies on the incidence of anxiety, depression, and GDM, blood glucose in pregnant women with GDM, delivery mode, and maternal and infant outcomes were included to be analyzed, and the source of anxiety and depression in pregnant women with GDM and related treatment measures were discussed.
Epstein–Barr Virus–Encoded Circular RNA CircBART2.2 Promotes Immune Escape of Nasopharyngeal Carcinoma by Regulating PD-L1
Authors: Ge Junshang , Wang Jie , Xiong Fang , Jiang Xianjie , Zhu Kunjie , Wang Yian , Mo Yongzhen , Gong Zhaojian , Zhang Shanshan , He Yi , Li Xiayu , Shi Lei , Guo Can , Wang Fuyan , Zhou Ming , Xiang Bo , Li Yong , Li Guiyuan , Xiong Wei , Zeng Zhaoyang
Published: July 2021

Epstein–Barr virus (EBV) infection is an established cause of nasopharyngeal carcinoma (NPC) and is involved in a variety of malignant phenotypes, including tumor immune escape. EBV can encode a variety of circular RNAs (circRNA), however, little is known regarding the biological functions of these circRNAs in NPC. In this study, EBV-encoded circBART2.2 was found to be highly expressed in NPC where it upregulated PD-L1 expression and inhibited T-cell function in vitro and in vivo. circBART2.2 promoted transcription of PD-L1 by binding the helicase domain of RIG-I and activating transcription factors IRF3 and NF-κB, resulting in tumor immune escape. These results elucidate the biological function of circBART2.2, explain a novel mechanism of immune escape caused by EBV infection, and provide a new immunotherapy target for treating NPC.

Significance:

This work demonstrates that circBART2.2 binding to RIG-I is essential for the regulation of PD-L1 and subsequent immune escape in nasopharyngeal carcinoma.
Valvular Calcific Deposits and Mortality in Peritoneal Dialysis Patients: A Propensity Score-Matched Cohort Analysis
Authors: Shen Aiwen , Jiang Linsen , Tian Yunhuan , Lu Ying , Wang Zhi , Shen Huaying , Song Kai , Feng Sheng
Published: July 2021

Objective: This study aimed to compare mortality between peritoneal dialysis (PD) patients with and without cardiac valve calcification (CVC). Methods: Patients undergoing PD at the dialysis center of the Second Affiliated Hospital of Soochow University from January 1, 2009, to June 31, 2016, were included and followed through December 31, 2018. The inclusion criteria were (1) age ≥18 years and (2) PD vintage ≥1 month. The exclusion criteria were (1) a history of hemodialysis or renal transplantation before PD; (2) diagnosed congenital heart disease, rheumatic heart disease, or hyperthyroid heart disease; and (3) loss to follow-up. Differences in mortality rates were compared using a Fine-Gray proportional hazards model. Results: A total of 310 patient cases were included in this study, including 237 cases without CVC (non-CVC group). The CVC group included 59 cases with aortic valve calcification (AVC), 6 cases with mitral valve calcification (MVC), and 8 cases of AVC associated with MVC. After propensity score matching, 68 pairs were selected. The multivariate competing risk regression analysis revealed that age (hazard ratio [HR]: 1.06, 95% confidence interval [95% CI]: 1.03–1.10, p < 0.001) and CVC group (HR: 1.83, 95% CI: 1.04–3.20, p < 0.05) were independent risk factors associated with mortality. No significant difference was observed in technique survival between the 2 groups. Conclusion: CVC is an independent risk factor for mortality in PD patients.
The Association of Sleep Habits and Advancing Age in Japanese Older Adults: Results from the National Center for Geriatrics and Gerontology Study of Geriatric Syndromes
Authors: Nakakubo Sho , Doi Takehiko , Tsutsumimoto Kota , Kurita Satoshi , Ishii Hideaki , Suzuki Takao , Shimada Hiroyuki
Published: July 2021

Background: The association of sleep habits with “advancing age among older adults” is not fully understood. Objectives: The purpose of the present study was to examine the association of sleep habits with advancing age among community-dwelling older adults in Japan. Methods: A total of 18,005 older people (mean age: 73.2 ± 6.0 years; 8,070 men and 9,935 women) from the National Center for Geriatrics and Gerontology Study of Geriatric Syndromes were analyzed. Participants were asked in face-to-face interviews about the times they usually go to bed, fall asleep, wake-up, and get up. The amount of time spent in bed and self-reported sleep duration were then calculated from the differences between these times. As other parameters, the subjects were also asked about sleep latency, time spent in bed after waking up, number of nocturnal awakenings, and duration of napping in a typical day. Results: The results of the Jonckheere-Terpstra test showed that all sleep parameters shifted to an earlier time (going to bed, falling asleep, waking up, and getting out of bed), longer duration (sleep duration, time spent in bed, sleep latency, time spent in bed after waking up, and napping), or more nocturnal awakenings with advancing age (all p < 0.01). Among the men, the time of waking up was not significantly associated with age, while among the women, the time of getting up was not significantly associated with age. Conclusion: These results from a large cohort show the age-related trends of sleep habits in community-dwelling older adults in Japan. Our results revealed that a longer duration and earlier timing of sleep are associated with advancing age.