bluuebunny/crossref_metadata_2025 huggingface dataset:
Ni/CGO-Based Electrolyte-Supported Cells During Co-Electrolysis: The Role of Feed Gas Impurities
Authors: Riegraf Matthias , Surrey Alexander , Costa Rémi
Published: July 2021

The electrochemical generation of syngas via simultaneous co-electrolysis of steam and CO2 in high temperature solid oxide cells and its consecutive catalytic upgrade has attracted growing interest over recent years since this pathway offers a sustainable route to the production of synthetic fuels. However, most solid oxide cell technologies have been developed for durable and efficient fuel cell operation and thus, their use in electrolysis mode leads to the emergence of different lifetime-limiting degradation mechanisms. For instance, strongly cathodic polarization of the cermet fuel electrode leads to irreversible Ni migration away from the electrode/electrolyte interface. Furthermore, carbon deposition can become an issue when local non-equilibrium, carbon monoxide-rich gas phase compositions are formed. All of these mechanisms have been shown to be particularly harmful in Ni/YSZ-based fuel-electrode supported cells. Ni/Gadolinium-doped ceria (CGO) electrodes offer a potentially promising alternative to alleviate these issues due the intrinsic high electro-catalytic activity and carbon mitigating effect of the ceria phase. Furthermore, the higher operating temperatures commonly used for electrolyte-supported cell (ESC) architectures may mitigate carbon deposition and impurity adsorption due to thermodynamic considerations. In addition, the thinner electrodes employed in ESC could help to avoid the formation of CO-rich gas phases at the electrode/electrolyte interface due to enhanced porous diffusion and thus, further prevent coking. With regards to durability of the reactor, the purity of the feed gases steam and CO2 becomes of great importance.

In the present study durability aspects of industrial Ni/CGO-based ESC are investigated in co-electrolysis mode under various operating conditions by means of current-voltage characteristics and electrochemical impedance spectroscopy. Durability was evaluated at different current densities for times of >=1500 h. Post-mortem analysis was carried out with scanning electron microscopy (SEM) to correlate the observed degradation phenomena with microstructural changes, particularly Ni migration. It is shown that the steam inlet gas has to be carefully purified to avoid the deposition of silica in the fuel electrode. Furthermore, electrochemical measurements performed in dry CO2 electrolysis demonstrate that sulfur impurities in the CO2 feed gas must be removed to achieve low degradation rates.
Thin Film Barrier Layers with Increased Performance and Reduced Long-Term Degradation in SOFCs
Authors: Bernadet Lucile , Baiutti Federico , Martinelli Francesca , Torrell Marc , Morata Alex , Montinaro Dario , Tarancón Albert
Published: July 2021

Gadolinium-doped ceria (CGO) is placed between yttrium-stabilized zirconia (YSZ) electrolyte and strontium-based electrode as a barrier layer to avoid the formation of SrZrO3 insulating phase during solid oxide fuel cell operation. This phase is observed in as-fabricated state-of-the-art cells, which evidences cation inter-diffusion during the sintering process [1]. The impact of this element to the degradation of cells is still under study, in part due to the high complexity of long-term tests necessary for the appropriate understanding of the involved phenomena. Among the efforts for improving barrier layers, the use of vacuum techniques such as sputtering and Large Area Pulsed Laser Deposition (LA-PLD) have been explored, allowing the implementation of dense layers at lower processing temperature compared with traditional deposition techniques (i. e. screen printing). CGO barrier layer thin film deposition and annealing parameters were previously optimized in a leading to an important increase of power density compared to a state-of-the-art button cell at 750ºC using a dense layer of 2 µm. Remarkable results were also obtained when the PLD barrier layer was up-scaled to large area cells of 80 cm2 and tested in short-stack configuration for long-term operation [2].

Here we present a thorough investigation of post mortem cells operated in short-stacks under realistic conditions during 15000h, comparing cells produced with state-of-the-art techniques with those produced by LA-PLD. At the light of the results, we provide tools for the improvement of the fabricated thin film layers, by finding the optimal combination between the protective role of the diffusion barrier layer, a good performance and the reduction of the PLD deposition time. Button cells with PLD barrier layer of 800 nm, 400 nm and 200 nm were fabricated and tested in SOFC mode at 750ºC. It is shown that the barrier layer thickness has no impact on the electrochemical performance and the durability which allows the use of thinner layers and a drastic reduction of the deposition time of the CGO barrier layer made by PLD.

Summed to the increased performance, the durability of the layers is evaluated, subjecting the cell with the thinnest film to an aging process for 3,500 h. Post-mortem characterization of the barrier layers and interfaces was conducted by Scanning-electronic microscope and Electron Probe Micro Analysis with Wavelength Dispersive X-Ray (EPMA-WDX) to observe any microstructural changes as well as any changes in composition due to cation inter-diffusion.

[1] Morales et al., Journal of Power Sources 344 (2017) 141-151.

[2] Morales et al. ACS Applied Energy Materials 1 (2018) 1955-1964.
Development of Fast Infiltration Technique for Metal Supported Solid Oxide Fuel Cells and Electrolyzers
Authors: Hu Boxun , Shen Fengyu , Cheng Yuan , Tucker Mike C
Published: July 2021

Our recently developed fast infiltration technique enables loading of nanostructured catalyst into porous metal-supported solid oxide fuel cells in 30 minutes per cycle compared to a few hours in the standard slow infiltration process. This technique maintains the advantages of metal supported solid oxide fuel cells (MS-SOFC) such as rapid thermal cycling, mechanical ruggedness, and redox tolerance while developing more efficient and stable fuel cells and electrolyzers. The impact of process parameters such as heating rate, number of infiltration cycle, and firing temperature on the cell performance and stability will be discussed. The crystallite sizes of the catalysts fired at a temperature range of 400 to 900°C were calculated from X-ray diffraction patterns using the Scherrer equation, and compared to the particle size of the catalysts obtained from scanning electron microscopy images. The electrochemical performance of as-fabricated cells tested in hydrogen, reformate, and ethanol fuels under identical test conditions will be presented and related to the infiltration process conditions and resulting catalyst structure. For the Pr-oxide cathode and Ni (40)-SDC (60) anode catalysts, firing at low temperature (400 to 600°C) yields high initial performance but degrades quickly due to coarsening of the small nanoparticle catalysts. Optimal firing temperature and infiltration numbers, and pretest and posttest characterization of the MS-SOFC architecture and interfaces will be discussed. Phenomena of mass transportation, phase change, catalyst coarsening, and Cr poisoning on the catalysts will be diagnosed by real-time electrochemical impedance spectra, thermal gravimetric analysis, and scanning electron microscopy.
Metal Supported Proton Conducting Ceramic Cell with Thin Film Electrolyte for Electrolysis Application
Authors: Zheng Haoyu , Han Feng , Sata Noriko , Riegraf Matthias , Dayaghi Amir Masoud , Norby Truls , Costa Rémi
Published: July 2021

Solid oxide fuel cells and electrolysis cells (SOC) have been comprehensively developed as energy conversion and storage devices in recent years. Compared with oxygen ion conducting SOC, proton-conducting ceramic (PCC) cells are more suitable for the operation in the temperature range of 450~650 oC. The reduced operating temperature makes it especially attractive for steam electrolysis application aiming at valorizing waste heat from industrial processes. Moreover, during electrolysis in PCC cells, by design, the water-splitting reaction occurs at the oxygen electrode which enables the production of pure hydrogen at the fuel electrode.

Based on previous research on metal-supported solid oxide cells (MS-SOC)[1] at DLR, MS-PCC with thin film electrolyte were investigated in this present study. The low temperature fabrication route (< 1000 °C) was chosen to avoid the serious corrosion of metal substrate at high temperature (1300~1400 °C) which is necessary for making the dense BaZrO3 based electrolyte in traditional sintering routes. In this case, pulsed laser deposition has been used for preparing the 1~2 µm thick electrolyte. Porous ferritic stainless steel, which has been used as the substrate, was cut into a round shape of 18 mm in diameter. To mitigate the Cr diffusion from metal substrate and formation of impurity phase between the metal substrate and NiO/BaZrxCe0.9-xY0.1O3-δ (NiO-BZCY) anode functional layer during processing or operation, Sr-doped LaMnO3 (LSM) was employed as the barrier layer in between. Both LSM and NiO-BZCY layers were processed by lamination of tape-cast thin films onto the metal substrate respectively and successfully co-sintered below 1000 °C. The thermomechanical stability of the thin film electrolyte was investigated by simulating thermal cycles from room temperature up to 950 °C. Platinum and Ba1-xGd0.8La0.2+xCo2O6-
δ
[2] were considered as oxygen electrode materials. Electrochemical characterization was carried out in both fuel cell and electrolysis operations. Advantages and current limitations of the presented cell design are discussed.

Part of this work was supported by the project DAICHI funded by EIG CONCERT-Japan. The German part was funded by the Federal Ministry of Education and Research (project 01DR18002), the Norwegian part funded by the Research Council of Norway (project 284289). The China Scholarship Council is acknowledged for the doctoral scholarship of Haoyu Zheng (201806160173).

Figure.1 Scanning electron microscopy (SEM) image of the metal supported proton conducting cells.

[1] Costa R., Han F., Szabo P., et al. Fuel Cells, 2018, 18 (3): 251-259.

[2] Vøllestad E., Strandbakke R., Tarach M., et al. Nature Materials, Jul, 2019, 18 (7): 752-759.

Figure 1
Characterization of Ag-Based Filler for Electrolyte/Metallic-Interconnect Joint in Metal-Supported Solid Oxide Fuel Cells Applications
Authors: Huang Liang-Wei , Liu Chien-Kuo , Cheng Yung-Neng , Lee Ruey-Yi
Published: July 2021

Metal-supported solid oxide fuel cells (MS-SOFCs) exhibit better electrochemical performance than conventional ceramic-supported cells at lower temperature due to their exceptional thermal, electrical, and mechanical properties. MS-SOFCs can withstand rapid thermal cycling operation and make it practical for mobile applications. A reliable seal is essential for electrolyte/metallic interconnect joint in MS-SOFC applications. In the present study, we proposed an Ag-Ge alloy filler as a high-temperature brazing sealant for use in MS-SOFCs. Commercial ferritic stainless steel (Crofer22H) and La1-XSrXGa1-yMgyO3-
δ (LSGM) substrate were employed as metallic interconnect and electrolyte for this study, respectively. The adhesive and hermetic characterization for the electrolyte/metallic interconnect joint joined by the Ag-Ge alloy filler were examined by using high-temperature leak test at elevated temperatures. Results showed that the leak rate of LSGM/Crofer22H coupon is 5 x 10-4 mbar∙l/s/cm after aging at 750 °C for 90 hours in He/air. In addition, SEM/EDS analyses also revealed that Ge element in the Ag-Ge filler was prone to diffuse toward Crofer22H and LSGM side, and thus improved the interfacial adhesion of the LSGM/Crofer22H joint.
Performance of Metal Supported SOFCs Operated in Hydrocarbon Fuels and at Low (<650˚C) Temperatures
Authors: Christensen Jens Ole , Hagen Anke , Sudireddy Bhaskar Reddy
Published: July 2021

Solid oxide cells (SOCs) are a key enabling technology for the required future renewable energy systems by providing an efficient link between the power, gas, and heat sectors. Specifically, solid oxide fuel cells (SOFCs) convert the chemical energy of a fuel into electricity and heat with high electrical efficiencies. Hydrogen is the obvious choice of fuel due to the only emissions being steam, however hydrocarbon fuels are an interesting and safe alternative to hydrogen, especially for mobile applications, facilitating easy integration into existing infrastructure. The state-of-the-art (SoA) Ni:YSZ (yttria-stabilized zirconia) composite fuel electrode is capable of direct oxidation of hydrocarbons or of reforming of hydrocarbon gas mixtures. Unfortunately, the material that facilitates the above reactions, nickel, is also an excellent carbon deposition catalyst. This is problematic, due to the associated volumetric changes and reduction in electrochemically active sites. Ultimately, the fuel electrode can delaminate from the electrolyte, causing a catastrophic failure of the cell.

Alternative fuel electrode materials are the key to avoid this. A-site deficient lanthanum doped strontium titanate (La0.4Sr0.4Fe0.03Ni0.03Ti0.94O3, LSFNT) based anodes, coated with Ni:CGO (gadolinium-doped ceria) electrocatalyst are a promising alternative - while avoiding Ni as a major part of the backbone, the infiltrated Ni ensures electrocatalytic activity. The co-infiltrated CGO serves to improve the ionic conductivity. Integrating these anodes into a metal supported (MS) design ensures lower cost and mechanical robustness. Full cells are manufactured through scalable tape casting and screen printing technology, including the metal support. Possible pitfalls for the MS-cell include vulnerability to corrosion of the metal support and decreased reforming activity due to less electrocatalyst (Ni) compared to the SoA-cell.

In this study, the reforming activity of methane in 3 different SOFCs is investigated: Cell 1 is with a SoA Ni:YSZ anode, cell 2 is with a LSFNT anode and cell 3 is with a LSFNT-FeCr anode. The investigation involves electrochemical characterization by impedance spectroscopy (EIS) and performance under applied current (I/V-curves) at temperatures 750˚C, 700˚C, 650˚C and 620˚C, so-called fingerprints, with special emphasis on the anode activity for reforming and water gas shift reaction. Furthermore, galvanostatic durability tests are conducted for the MS-cells (cell 2 and cell 3) with focus on the durability at low temperature (650˚C) and corrosion resistance at medium to high fuel utilization (ca. 50%). The degradation of the tested cells is examined by comparing the electrochemical performance before and after durability testing.
Field Test Result of Residential SOFC CHP System Over 10 Years, 89000 Hours
Authors: Suzuki Minoru , Inoue Shuichi , Shigehisa Takashi
Published: July 2021

The maximum operating time, without stack replacement, residential SOFC power generation unit (manufactured by Kyocera in 2009), which was installed by Osaka Gas in a house in 2009, has exceeded over 10 years, 89,000 power generating hours. It may be the first data as a SOFC system to succeed in operating in the actual field for 10 years. We will report performance results for 10 years. In 2004, Osaka Gas and Kyocera started joint development of residential SOFC CHP system and from 2007, we conducted series of field test in the SOFC demonstration project operated by NEDO and NEF. At that time, various technical issues still remained, and after joint development with Aisin and Toyota Motor, it was mass-produced and commercialized in 2012. We also mention current status of residential SOFC (Manufactured by Aisin, Stack supplied by Kyocera), which have sold more than total 80,000 units at Osaka Gas.
Effect of Ce/Zr Ratio on Thermal and Chemical Expansions and CO2 Resistance of Rare Earth-Doped Ba(Ce,Zr)O3 Perovskite-Type Proton Conductors
Authors: Nomura Katsuhiro , Shimada Hiroyuki , Yamaguchi Yuki , Shin Woosuck , Okuyama Yuji , Mizutani Yasunobu
Published: July 2021

To make clear the effect of Ce/Zr ratio on the thermal and chemical expansions of rare earth-doped Ba(Ce,Zr)O3 perovskite-type proton conductors, we investigated the crystal structures (crystal phase, lattice constants, lattice volume, etc.) of Ba(Ce0.7Zr0.1Y0.1Yb0.1)O3-
δ, Ba(Ce0.4Zr0.4Y0.1Yb0.1)O3-δ, etc. on the basis of Rietveld refinement results of high-temperature X-ray diffraction data measured between 298 and 1173 K under dry and wet N2 atmospheres. We will also report on the CO2 resistance of these proton conductors.
Redox Durability of Ni-Co Alloy Cermet Anodes for SOFCs
Authors: Matsumoto Kohei , Tachikawa Yuya , Matsuda Junko , Taniguchi Shunsuke , Sasaki Kazunari
Published: July 2021

Introduction

Nickel (Ni) is commonly used as the anode material of SOFCs. However, in the power generation, as the oxygen partial pressure in the downstream of the SOFC systems increases, the metallic Ni can be oxidized to nickel oxide (NiO), causing volume expansion (1) This volume expansion and shrinkage in redox cycles cause irreversible degradation, by breaking electrode microstructure. Highly durable SOFC anodes using Ni-based alloy are therefore desirable (2). Here in this study, we focus on the Ni-Co alloy, by preparing a new Ni-Co-GDC cermet anode using the Ni-Co alloy, and evaluate the effects of cobalt addition on their redox durability.

Experimental

The cells were fabricated by screen-printing electrode paste on the electrolyte plate, followed by heat treatment. Scandia-Stabilized Zirconia (ScSZ, 10mol% Sc2O3-1mol% CeO2-89mol% ZrO2) was used as the solid electrolyte. Ni-Co-GDC cermet anodes were prepared by mixing Ni-Co-based oxide powder by ammonia co-precipitation with Ce0.9Gd0.1O2 (GDC) in a specific ratio by weight. La1-xSrxMnO3 (LSM) powder was used as the cathode material. The electrochemical characteristics of the cells, with the Ni-Co cermet anodes, were evaluated by measuring I-V measurements coupled with the current interruption method under the condition at 800oC, where 3%-humidified hydrogen fuel was supplied to the anode. Furthermore, the redox stability was evaluated using the durability test protocol simulating the fuel interruption (3). Anode microstructure was observed by a focused-ion beam system coupled with a scanning electron microscope (FIB-SEM).

Results and discussion

Figure 1 shows the I-V characteristics and overvoltages of the Ni-Co-GDC anode with various Co concentrations at 800oC with 3%-humidified hydrogen fuel. With increasing the Co content, the electrochemical performance decreased due to an increase in overvoltages. However, when the Co content was as low as 5 mol%, performance decrease was negligible. Figure 2 shows the redox stability of the Ni-Co-GDC anode evaluated by using the durability test protocol simulating the fuel interruption. With increasing the Co content, the redox stability was improved, associated with relatively-low ohmic losses. The microstructure of Ni-Co-GDC anodes will be reported and discussed.

References

Q. Fang et al., Int. J. Hydrogen Energy, 40, 1128 (2015).

Y. Ishibashi et al., J. Electrochem. Soc.,
167, 124517 (2020).

M. Hanasaki et al., J. Electrochem. Soc., 161 (9), F850-60 (2014).

Figure 1
Effect of Sn, Cu, and Ag Modification on Electrochemical Performance and Carbon Tolerance of Biogas-Operated Ni/YSZ and Ni/ScCeSZ SOFC Anodes
Authors: Jiang Zeyu , El-Kharouf Ahmad , Steinberger-Wilckens Robert
Published: July 2021

This work demonstrates the effect of Sn, Cu, and Ag modification on the electrochemical performance and carbon tolerance of biogas-operated Ni/YSZ and Ni/ScCeSZ SOFC anodes. The tested cells were fabricated from commercial materials via aqueous tape casting method. A reverse co-casting technique was utilized to manufacture GDC-ScCeSZ-Ni/ScCeSZ half cells. An LSCF (La0.6Sr0.4Cr0.2Fe0.8O3) cathode was painted on the sintered half cells to ensure good performance at intermediate operating temperatures (700-800 °C). 1 wt% of Sn, Cu, and Ag (respect to Ni) were infiltrated into the anode scaffold and followed by calcination at different temperatures. Prepared cells were firstly tested at 700-800 °C in hydrogen fuel (H2:N2=3:1) for 24 h and then switched to simulated biogas (CH4:CO2:N2=2:1:1) for another 24 h. Electrochemical characterizations such as OCV, I-V, potentiostatic, galvanostatic, and electrochemical impedance spectroscopy were performed on each SOFC single cell. Scanning electron spectroscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray powder diffraction (XRD) were conducted to analyse the microstructure, surface elemental distribution, and electrochemical catalyst crystal structure of the prepared anodes, respectively.

The obtained experimental results were compared with our previous work on 1 wt% Sn, Cu and Ag doped Ni/YSZ anodes. Carbon deposition on the modified Ni/YSZ anode surface was successfully suppressed after 24 h simulated biogas operation at 750 °C. Furthermore, the addition of a small amount of dopant significantly improved the electrochemical performance and long-term stability under dry methane reforming condition, especially for Sn and Ag-doped anodes. Cu agglomeration might occur at high operating temperature because of copper’s low melting point, resulting in unchanged cell performance under biogas operation. Therefore, the Cu-doped Ni/ScCeSZ/LSCF cells are expected achieve better cell performance at slightly reduced operating temperature.
A semiautomated measurement of muscle fiber size using the Imaris software
Authors: Gilda Jennifer E. , Ko Joon-Hyuk , Elfassy Aviv-Yvonne , Tropp Nadav , Parnis Anna , Ayalon Bar , Jhe Wonho , Cohen Shenhav
Published: July 2021

The size and shape of skeletal muscle fibers are affected by various physiological and pathological conditions, such as muscle atrophy, hypertrophy, regeneration, and dystrophies. Hence, muscle fiber cross-sectional area (CSA) is an important determinant of muscle health and plasticity. We adapted the Imaris software to automatically segment muscle fibers based on fluorescent labeling of the plasma membrane and measure muscle fiber CSA. Analysis of muscle cross sections by the Imaris semiautomated and manual approaches demonstrated a similar decrease in CSA of atrophying muscles from fasted mice compared with fed controls. In addition, we previously demonstrated that downregulation of the Ca2+-specific protease calpain-1 attenuates muscle atrophy. Accordingly, both the Imaris semiautomated and manual approaches showed a similar increase in CSA of fibers expressing calpain-1 shRNA compared with adjacent nontransfected fibers in the same muscle cross section. Although both approaches seem valid for measurements of muscle fiber size, the manual marking method is less preferable because it is highly time-consuming, subjective, and limits the number of cells that can be analyzed. The Imaris semiautomated approach is user-friendly, requires little training or optimization, and can be used to efficiently and accurately mark thousands of fibers in a short period. As a novel addition to the commonly used statistics, we also describe statistical tests that quantify the strength of an effect on fiber size, enabling detection of significant differences between skewed distributions that would otherwise not be detected using typical methods.
Rapid postmortem ventilation improves donor lung viability by extending the tolerable warm ischemic time after cardiac death in mice
Authors: Yu Junyi , Xu Che , Lee Janet S. , Alder Jonathan K. , Wen Zongmei , Wang Guifang , Gil Silva Agustin Alejandro , Sanchez Pablo G. , Pilewski Joseph M. , McDyer John F. , Wang Xingan
Published: July 2021

Uncontrolled donation after cardiac death (uDCD) contributes little to ameliorating donor lung shortage due to rapidly progressive warm ischemia after circulatory arrest. Here, we demonstrated that nonhypoxia improves donor lung viability in a novel uDCD lung transplant model undergoing rapid ventilation after cardiac death and compared the evolution of ischemia-reperfusion injury to mice that underwent pulmonary artery ligation (PAL). The tolerable warm ischemia time at 37°C was initially determined in mice using a modified PAL model. The donor lung following PAL was also transplanted into syngeneic mice and compared with those that underwent rapid ventilation or no ventilation at 37°C before transplantation. Twenty-four hours following reperfusion, lung histology, [Formula: see text]/[Formula: see text] ratio, and inflammatory mediators were measured. Four hours of PAL had little impact on [Formula: see text]/[Formula: see text] ratio and acute lung injury score in contrast to significant injury induced by 5 h of PAL. Four-hour PAL lungs showed an early myeloid-dominant inflammatory signature when compared with naïve lungs and substantially injured 5 h PAL lungs. In the context of transplantation, unventilated donor lungs showed severe injury after reperfusion, whereas ventilated donor lungs showed minimal changes in [Formula: see text]/[Formula: see text] ratio, histologic score, and expression of inflammatory markers. Taken together, the tolerable warm ischemia time of murine lungs at 37°C can be extended by maintaining alveolar ventilation for up to 4 h. Nonhypoxic lung undergoing warm ischemia-reperfusion injury shows an early transcriptional signature of myeloid cell recruitment and extracellular matrix proteolysis before blood-gas barrier dysfunction and significant tissue damage.
Sex-specific differences in plasma levels of FXII, HK, and FXIIa-C1-esterase inhibitor complexes in community-acquired pneumonia
Authors: Ehrlich Kristin , Wilhelm Jochen , Markart Philipp , Weisser Heike , Wolff Jens-Christian , Bein Gregor , Pak Oleg , Barreto Guillermo , Weissmann Norbert , Schramm Fabian , Seeger Werner , Schaefer Liliana , Kuebler Wolfgang M. , Wygrecka Malgorzata ,   and members of the CAPNETZ Study Group
Published: July 2021

Sex-dependent differences in immunity and coagulation play an active role in the outcome of community-acquired pneumonia (CAP). Contact phase proteins act at the crossroads between inflammation and coagulation thus representing a point of convergence in host defense against infection. Here, we measured the levels of factor XII (FXII), FXIIa-C1 esterase inhibitor (C1INH) complexes, and high-molecular-weight kininogen (HK) in plasma of patients with CAP and correlated them to clinical disease severity. Levels of FXIIa-C1INH/albumin ratio were elevated, irrespective of sex, in plasma of patients with CAP ( n = 139) as compared with age-matched donors ( n = 58). No simultaneous decrease in FXII levels, indicating its consumption, was observed. Stratification by sex revealed augmented FXII levels in plasma of women with CAP as compared with sex-matched donors yet no apparent differences in men. This sex-specific effect was, however, attributable to lower FXII levels in female donors relative to men donors. Plasma estradiol levels mirrored those for FXII. Levels of HK/albumin ratio were decreased in CAP plasma as compared with donors, however, after stratification by sex, this difference was only observed in women and was related to higher HK/albumin values in female donors as opposed to male donors. Finally, strong negative correlation between plasma levels of HK/albumin ratio and CAP severity, as assessed by CRB65 score, in males and females was observed. Our study identifies sex-dependent differences in plasma levels of the contact phase proteins in elderly subjects that may contribute to specific clinical outcomes in CAP between men and women.
Increased plasma and milk short-chain acylcarnitine concentrations reflect systemic LPS response in mid-lactation dairy cows
Authors: Xu Wei , Grindler Sandra , Dänicke Sven , Frahm Jana , Kenéz Ákos , Huber Korinna
Published: July 2021

Lipopolysaccharides (LPS) challenge the metabolic integrity of high-yielding dairy cows, activating the immune system and altering energy metabolism. Fatty acid oxidation, a major energy-gaining pathway, can be improved by supplementary carnitine, facilitating the transport of fatty acids into mitochondria. The metabolic response to the LPS challenge could alter both the plasma and the milk metabolome. Plasma and milk samples collected from cows treated with ( n = 27) or without ( n = 27) dietary carnitine, before and after intravenous administration of LPS, were subjected to a targeted metabolomics analysis. Multivariate statistical analyses revealed that both plasma and milk metabolome changed in response to the LPS challenge in both the carnitine-supplemented and the control cows. Short-chain acylcarnitines (carbon chain length C2, C3, C4, and C5) and long-chain acylcarnitines (C14, C16, and C18) had the highest performance to indicate LPS response when testing the predictive power of single metabolites using receiver-operator characteristics (ROC) analysis. The maximum area under a ROC curve (AUC) was 0.93. Biogenic amines, including sarcosine, and amino acids such as glutamine and isoleucine had AUC > 0.80 indicating metabolic changes due to the LPS challenge. In summary, the metabolites involved in the LPS response were acylcarnitines C2 and C5, sarcosine, glutamine, and isoleucine in plasma, and acylcarnitines C4 and C5 in milk. The interrelationship of plasma and milk metabolome included correlation of acylcarnitines C2, C4, and C5 between plasma and milk.
Numerical Investigation of Fluid Flow past Four Cylinders at Low Reynolds Numbers
Authors: Ahmad Shafee , Ul-Islam Shams
Published: July 2021

A numerical investigation on the effects of separation ratios and Reynolds numbers on the flow around four square cylinders in diamond arrangement has been carried out using the lattice Boltzmann method. The separation ratios between the cylinders vary fromg∗=1to 15. The Reynolds numbers based on the diameter of the square cylinder and the inlet uniform inflow velocity are selected from Re = 80 to 160. The computations show that a total of five different flow regimes are observed over the selected ranges: single bluff-body, quasi-unsteady, chaotic flow, in-phase synchronized vortex shedding, and antiphase synchronized vortex shedding flow regimes. It is found that the flow features significantly depend on both the separation ratio and Reynolds number, with the former’s influence being more than the latter’s. We found that the critical spacing for four square cylinders in diamond arrangement for selected Reynolds numbers (80 ≤ Re ≤ 160) is in the range of 2 ≤ g∗ ≤ 5. The results reveal that the presence of secondary cylinder interaction frequencies indicates that, for chaotic flow regime, the wake pattern is not stable and there is a strong interaction of gap flows and continuous change in the direction of shed vortices behind the cylinders. The effects of theg∗and Re on fluid forces, vortex shedding frequency, and flow separation have been examined in detail.
Upregulation of ECT2 Predicts Adverse Clinical Outcomes and Increases 5-Fluorouracil Resistance in Gastric Cancer Patients
Authors: Zhang Hua , Geng Yuan , Sun Chunhui , Yu Jin
Published: July 2021

Background. The abnormal expression and prognosis prediction of epithelial cell transforming sequence 2 (ECT2) in gastric cancer (GC) has been reported. However, the effect of ECT2 on 5-fluorouracil (5-Fu) resistance in GC is unclear. This research aims to solve the abovementioned problems. Methods. Gene expression was detected by RT-qPCR and Western blot analysis. Cell viability was evaluated by the colony formation assay, MTT assay, and flow cytometric analysis. Transwell and wound healing assays were used to detect cell metastasis. Results. Upregulation of ECT2 was found in stomach adenocarcinoma (STAD) and GC tissues. In addition, high ECT2 expression can predict adverse clinical outcomes in GC patients. More importantly, ECT2 knockdown weakened the resistance of 5-FU in GC cells. ECT2 silencing reduced the cell migratory and invasive abilities of GC cells treated with 5-FU. We also found that downregulation of ECT2 increased 5-FU sensitivity in GC cells by downregulating P-gp, MRP1, and Bcl-2. Conclusion. Upregulation of ECT2 can predict adverse clinical outcomes and increase 5-FU resistance in GC patients.
[Retracted] Improvement on Mechanical Properties of Submerged Friction Stir Joining of Dissimilar Tailor Welded Aluminum Blanks
Authors: Suryanarayanan R. , Sridhar V. G. , Natrayan L. , Kaliappan S. , Merneedi Anjibabu , Sathish T. , Yeshitla Alazar
Published: July 2021

Friction stir welding is a solid‐state welding method that produces joints with superior mechanical and metallurgical properties. However, the negative effects of the thermal cycle during welding dent the mechanical performance of the weld joint. Hence, in this research study, the joining of aluminum tailor welded blanks by friction stir welding is carried out in underwater conditions by varying the welding parameters. The tensile tests revealed that the underwater welded samples showed better results when compared to the air welded samples. Maximum tensile strength of 229.83 MPa was obtained at 1000 rpm, 36 mm/min. The improved tensile strength of the underwater welded samples was credited to the suppression of the precipitation of the secondary precipitates due to the cooling action provided by the water. The lowest hardness of 72 HV was obtained at the edge of the stir zone which indicated the weakest region in the weld zone.
Collaborative Control of Multimotor Systems for Fixed‐Time Optimisation Based on Virtual Main‐Axis Speed Compensation Structure
Authors: Zhang Changfan , Xiao Mingjie , He Jing , Liu Zhitian , Yang Xingxing , Zhang Qian , Chen Hongrun
Published: July 2021

In response to the high‐speed and high‐precision collaborative control requirements of the multimotor system for filling, a new type of virtual master‐axis control structure is proposed and a multimotor fixed‐time optimized collaborative control algorithm is designed. Firstly, coupling relationship between virtual and slave motors is effectively established by designing a velocity compensation module for the virtual motor. Secondly, the sliding mode observer (SMO) is used to reconstruct the composite disturbance composed of motor parameter perturbation and load disturbance. Finally, the variable gain terminal sliding mode controller (SMC) is designed to ensure that each slave motor can track the given value within a fixed time. The fast convergence of the system can be proved by the fixed‐time convergence theorem and Lyapunov’s stability theorem. The simulation results show that, compared with the traditional virtual main‐axis control strategy, the proposed method is more effective for the tracking control of each slave motor in the initial stage.
Field and Numerical Investigation on the Coal Pillar Instability of Gob‐Side Entry in Gently Inclined Coal Seam
Authors: Ta Xupeng , Wan Zhijun , Zhang Yuan , Shi Peng , Wei Zejie , Sun Xin , Jia Liangliang
Published: July 2021

In order to study the coal pillar stability of gob‐side entry in gently inclined coal seam, a comprehensive method including theoretical analysis, numerical modeling, and field monitoring was applied to study its fracturing and instability mechanism. The results show that the uneven horizontal stress was the internal cause of entry asymmetric deformation and failure in inclined coal seam. In gently inclined coal seam, the rotation movement of the main roof and stress distribution were closely related to inclination of the coal seam. Based on the asymmetric deformation characteristics and mechanisms of entry, a collaborative control technology of roof cutting for pressure relief and support strengthening has been put forward. The research results have practical signiﬁcance for revealing the mechanism of entry damage in gently inclined coal seam mining and proposing engineering measures to prevent coal pillar damage and disaster occurrence.
TIO Associated with Hyperparathyroidism: A Rarity, a Rule, or a Novel HPT-PMT Syndrome—A Case Study with Literature Review
Authors: Salim Michael , Behairy Mohannad Samy , Barengolts Elena
Published: July 2021

Objective. Association of primary hyperparathyroidism (pHPT) with phosphaturic mesenchymal tumors (PMT) is rarely reported. This report entertains the hypothesis of the causal association of HPT with tumor-induced osteomalacia (TIO) and of the existence of HPT-PMT syndrome. Case Presentation. A 49-year-old man presented with fragility rib fractures, generalized bone pain, and muscle weakness worsening over the past 3 years. Initial tests demonstrated hypophosphatemia and high PTH. The diagnosis of pHPT was entertained, but parathyroid scan was negative. During a 2-year follow-up, the patient reported minimal improvement of symptoms after intermittent treatment with calcitriol and phosphate. Biochemical evaluation showed persistent hypophosphatemia with renal phosphate wasting, elevated FGF23, and osteopenia on DXA scan. TIO was suspected. Multiple MRIs and whole-body FDG-PET scans were inconclusive. The patient subsequently underwent 68Ga-DOTATATE PET-CT, which revealed a somatostatin receptor-positive lesion in the lung. The resected mass was confirmed as PMT. The patient had dramatically improved symptoms, normal phosphate, calcium, and FGF23. During follow-up over 3 years postsurgery, the patient had slowly rising calcium and persistently elevated PTH. Conclusion. The debate whether the patient had pHPT or tertiary HPT prompted literature review showing that aberrant genes including FGFR1, FGF1, fibronectin 1, and Klotho were mechanistically involved in the HPT-PMT association. This case highlights the pitfalls contributing to delayed diagnosis and treatment of TIO and hypothesizes the association between pHPT and PMT.
Cryptographic Secrecy Analysis of Adaptive Steganographic Syndrome-Trellis Codes
Authors: Du Hansong , Liu Jiufen , Tian Yuguo , Luo Xiangyang
Published: July 2021

Compared with traditional steganography, adaptive steganography based on STC (Syndrome-Trellis Codes) has extremely high antidetection ability and has been a mainstream and hot research direction in the field of information hiding over the past decades. However, it is noted, in specific scenarios, that a small number of methods can extract data from STC-based adaptive steganography, indicating security risks related to such algorithms. In this manuscript, the cryptographic secrecy of this kind of steganography is analyzed, on condition of two common attacks: stego-only attack and known-cover attack, respectively, from three perspectives: steganographic key equivocation, message equivocation, and unicity distance of the steganographic key. Focusing on the special layout characteristics of the parity-check matrix of STC, under the two attack conditions, the theoretical boundaries of the steganographic key equivocation function, the message equivocation function, and the unicity distance of the steganographic key are separately obtained, showing the impact of the three elements: the submatrix size, the randomness of the data, and the cover object on the cryptographic secrecy of the STC-based adaptive steganography, resulting in a theoretical reference to accurately judge the cryptographic secrecy of such steganography and design more secure steganography methods.
Evaluation of the Adaptability of an EPB TBM to Tunnelling through Highly Variable Composite Strata
Authors: Li Tao , Zhan Jinwu , Li Chao , Tan Zhongsheng
Published: July 2021

The adaptability of an earth pressure balance (EPB) tunnel boring machine (TBM) to complex geological strata needs to be evaluated when a tunnel project is set up. It is helpful for better design and more suitable technical parameters of the machine. Because the factors that influence adaptability are numerous and interrelated, their effects also differ; hence, a quantitative assessment of adaptability is generally difficult. In the present study, a method for quantitatively evaluating the excavation adaptability of an EPB TBM was developed using an analytic hierarchy process (AHP) and fuzzy comprehensive evaluation. The method first involves an initial selection of factors that may influence tunnelling. Based on the expert questionnaire and their influence weights determined by AHP, the 10 evaluation indexes from 25 primary indexes were selected to establish the evaluation index system (EIS) including a target, criteria, and index level. Fuzzy membership functions are then derived one after another based on the effect of each evaluation index on the EBP TBM tunnelling process. A fuzzy mathematical method was finally presented to determine the adaptability of an EPB TBM excavation performance. The proposed method was applied to two special sections of diameter 6.98 m excavated by two EPB TBMs in the Shenzhen Metro Line 11 project. The geological exploration shows that these two tunnel sections pass through typical composite strata in Shenzhen. The determined adaptability grades of the EPB TBMs used for composite strata were confirmed by the actual tunnel excavation. It indicates that the developed method is reasonable and useful to evaluate tunnelling adaptability of EPB TBM.
Antioxidant, Cytotoxic, and Antibacterial Activities of the Selected Tibetan Formulations Used in Gandaki Province, Nepal
Authors: Dhakal Madan , Poudel Prakash , Jha Upma , Jaiswal Suresh , Joshi Khem Raj
Published: July 2021

Background and Objective. Tibetan medicine is one of the earliest-known traditional medicines. This study aimed to evaluate the antioxidant, cytotoxic, and antibacterial potential of ethanolic extracts of nine common Tibetan formulations. Materials and Methods. An open-ended and semistructured questionnaire was used for an ethnomedicinal survey of the Tibetan formulations practiced in four Tibetan refugee settlements in Gandaki Province, Nepal. Based on the ethnomedicinal survey data, commonly used nine formulations were selected (Aru-18, Basam, Dadue, Dashel, Mutik-25, Raab Ga Yangzin Tea, Serdok-11, Sugmel-10, and Yungwa-4) to test biological activities. Antioxidant activity was evaluated using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging method. The cytotoxicity was examined by using the Allium cepa L. root tip meristem model. Similarly, the antibacterial effect was assessed by using well diffusion and broth dilution methods. Results. An ethnomedicinal survey showed a total of 52 Tibetan formulations were generally used by respondents for common diseases such as stomach disorders, diabetes, and migraine. From the antioxidant activity test, Sugmel-10 showed the highest DPPH free-radical-scavenging activity (IC50 1.8 μg/ml) and Yungwa-4 showed the lowest activity (IC50 5.2 μg/ml). Also, from the cytotoxic activity, the A. cepa root meristem model exhibited significant dose- and time-dependent growth suppression in Basam, Dadue, Mutik-25, and Serdok-11 as compared with cyclophosphamide standard drug. Similarly, Basam showed a good antibacterial effect having MIC 20 mg/ml and MBC 100 mg/ml against Enterococci faecalis. Conclusion. Research showed that Tibetan people preferred Tibetan formulations for the treatment and mitigation of several diseases. The result of antioxidant, cytotoxic, and antibacterial activities experimentally justified the ethnomedicinal value of nine common formulations (Aru-18, Basam, Dadue, Dashel, Mutik-25, Raab Ga Yangzin Tea, Serdok-11, Sugmel-10, and Yungwa-4). To the best of our knowledge, this study was performed for the first time in Nepal. Results from this preliminary study open the door to the scientific world to perform extensive pharmacological studies for designing and developing new therapeutic agents.
Interleukin-18: A Novel Participant in the Occurrence, Development, and Drug Therapy of Obliterative Bronchiolitis Postlung Transplantation
Authors: Shu Ping , Zhang Wei , Zhang Yanfei , Zhao Yanfeng , Li Yuping , Zhang Xiaoqing
Published: July 2021

Background. Obliterative bronchiolitis (OB) was a main cause of deterioration of long-term prognosis in lung transplant recipients after the first posttransplant year. Proinflammatory cytokine interleukin-18 (IL-18) strengthened both the natural immunity and acquired immunity and played an important role in organ transplantation. The roles of IL-18 in the occurrence, development, and drug treatment of OB remained unclear. Methods. Small interfering RNA (siRNA) against mouse IL-18 (siRNA-IL-18) was used to silence IL-18 expression. Mouse heterotopic tracheal transplantation model was used to simulate OB. Recipient mice were divided into 5 groups (

n
=
12

) according to donor mouse strains and drug treatment: isograft group, allograft group, allograft+tacrolimus group, allograft+azithromycin group, and allograft+tacrolimus+azithromycin group. The luminal obliteration rates were pathological evaluation. Expressions of cytokines and MMPs were detected by real-time PCR, western blot, and enzyme chain immunosorbent assay (ELISA). Results. The luminal obliteration rates of IL-18 of the siRNA-IL-18 group were significantly lower than those of the negative control group (

p
<
0.0001

) and the blank control group (

p
=
0.0002

). mRNA expressions of IFN-γ, EMMPRIN, MMP-8, and MMP-9 of the siRNA-IL-18 group were significantly lower than those of the negative and blank control groups. No tracheal occlusion occurred in grafts of the isograft group. The rates of tracheal occlusion of the allograft group, allograft+tacrolimus group, allograft+azithromycin group, and allograft+tacrolimus+azithromycin group were

72.17
±
4.66

%,

40.33
±
3.00

%,

38.50
±
2.08

%, and

23.33
±
3.24

%, respectively. There were significant differences between the 4 groups (

p
<
0.001

). Serum protein expressions of IL-17 (

p
=
0.0017

), IL-18 (

p
=
0.0036

), IFN-γ (

p
=
0.0102

), and MMP-9 (

p
=
0.0194

) were significantly decreased in the allograft+tacrolimus+azithromycin group compared to the allograft group. Conclusions. IL-18 could be a novel molecular involved in the occurrence, development, and drug treatment of OB.
On Numerical Thermal Transport Analysis of Three-Dimensional Bioconvective Nanofluid Flow
Authors: Cui Jifeng , Munir Shahzad , Farooq Umer , Rabie Mohammed Elamin Ahmed , Muhammad Taseer , Razzaq Raheela
Published: July 2021

In this paper, a numerical study is presented for the 3D mathematical model of bioconvective boundary layer flow having nanoparticles and motile microorganisms on a curved sheet under isothermal conditions. Using an appropriate choice of similarity transformations, the problem reduces to coupled ordinary nonlinear equations, and this system is then treated with bvp4c (a MATLAB-based solver) to get the desired solution with good accuracy. The repercussion of distinct important dimensionless numbers such as thermophoresis, buoyancy ratio, Lewis number, and Brownian number on the velocity, temperature, and volume fraction of nanoparticles is presented graphically and is discussed in context with their importance on flow dynamics. Moreover, the physical impact of various parameters on motile microorganism density, the local Sherwood number, the local Nusselt number, and the local skin friction coefficients is analyzed and presented in tables. Qualitative analysis also reveals that the Brownian motion parameter, Peclet number, and Schmidt number have an inverse impact on the density microorganisms.