Mitigation of chromium poisoning in solid oxide fuel cell cathodes

Solid oxide fuel cells (SOFCs) have several advantages as electrochemical energy generation devices, including high energy conversion efficiency, easily sequesterable emissions, and high fuel flexibility. However, durability issues still limit the commercial viability of SOFCs. At high temperature operating conditions, volatile hexavalent chromium oxide/hydroxide species are formed from the thermally grown oxide (TGO) scale on stainless-steel interconnects. These vapor phase species are reduced and deposited on the electrochemically active areas in the cathode. This phenomenon, known as ‘chromium poisoning,’ is one of the primary reasons for long-term degradation of SOFC performance. In this study, two strategies were explored to mitigate Cr poisoning. The first strategy is ‘electrochemical cleaning’, based on periodic reversible operation in a solid oxide electrolyser cell (SOEC) mode, which mitigates the deleterious effects of chromium poisoning by oxidizing the deposits species back into the vapor phase. Electrochemical cleaning of cells with lanthanum strontium manganite (LSM) cathodes showed that under the conditions tested, deposited Cr2O3 can be effectively removed, significantly reversing the deleterious effects of chromium poisoning. However, Cr-Mn spinel deposits that were also formed at the cathode/electrolyte interface remain. In order to demonstrate that electrochemical cleaning can be carried out periodically without damaging the cell, cells were subjected to three cycles of repeated poisoning and cleaning. It was found that a similar level of degradation and recovery happened after each cycle. After the third cycle, the cell still maintained the initial level of power output, indicating that periodic electrochemical cleaning under mild electrolytic conditions is an effective method to reverse chromium poisoning without damaging the cell. The second strategy explored was the deposition of protective coatings on the stainless-steel interconnects. Deposition of spinel coatings by DC and AC electrophoretic deposition (EPD) on flat and porous SUS 430 stainless steel substrates was studied. The required variations in deposition parameters to obtain uniform EPD coatings on porous substrates with increasing geometrical complexity were explored. Four spinel compositions for these coatings were studied; CuMn2O4, CuNi0.2Mn1.8O4, MnCo2O4, and MnFe0.34Co1.66O4. The coatings were evaluated based on multiple criteria; including phase stability, microstructural stability, conductivity, Cr gettering ability, ability to act as a diffusion barrier to outward chromium and inward oxygen diffusion at 700ºC and 800ºC in dry and humid air, and the ability to limit the increase in the area specific resistance (ASR) during high temperature oxidation exposures. The results showed that CuNi0.2Mn1.8O4 was the best candidate for the coatings

AFPN: Asymptotic Feature Pyramid Network for Object Detection

Multi-scale features are of great importance in encoding objects with scale variance in object detection tasks. A common strategy for multi-scale feature extraction is adopting the classic top-down and bottom-up feature pyramid networks. However, these approaches suffer from the loss or degradation of feature information, impairing the fusion effect of non-adjacent levels. This paper proposes an asymptotic feature pyramid network (AFPN) to support direct interaction at non-adjacent levels. AFPN is initiated by fusing two adjacent low-level features and asymptotically incorporates higher-level features into the fusion process. In this way, the larger semantic gap between non-adjacent levels can be avoided. Given the potential for multi-object information conflicts to arise during feature fusion at each spatial location, adaptive spatial fusion operation is further utilized to mitigate these inconsistencies. We incorporate the proposed AFPN into both two-stage and one-stage object detection frameworks and evaluate with the MS-COCO 2017 validation and test datasets. Experimental evaluation shows that our method achieves more competitive results than other state-of-the-art feature pyramid networks. The code is available at \href{https://github.com/gyyang23/AFPN}{https://github.com/gyyang23/AFPN}

Intraocular complement activation is related to retinal vascular and neuronal degeneration in myopic retinopathy

PurposeTo investigate the relationship between the intraocular levels of complement proteins and myopia-related retinal neuronal and vascular degeneration.MethodsAqueous humour from 147 myopic patients, including 60 low-myopia and 87 high-myopia were collected during Implantable Collamer Lens implantation surgery. All participants received comprehensive ophthalmic examinations, including logMAR best corrected visual acuity, axial length measurement, fundus photography and ocular B-scan ultrasonography. The myopic eyes were further classified into simple myopia (SM, n = 78), myopic posterior staphyloma (PS, n = 39) and PS with myopic chorioretinal atrophy (PS + CA, n = 30). Retinal thickness and vascular density in the macula (6 mm × 6 mm) and optic nerve head (4.5 mm × 4.5 mm) were measured using Optical Coherence Tomography (OCT) and OCT angiography (OCTA). The levels of complement proteins including C1q, C3, C3b/iC3b, C4, CFB, CFH, C2, C4b, C5, C5a, CFD, MBL and CFI in the aqueous humour were measured using the Luminex Multiplexing system. The real-time RT-PCR was conducted to examine the expression of complement genes (C1q, C2, C3, C4, CFI and CFD) in the guinea pig model of long-term form deprivation-induced myopic retinal degeneration.ResultsOCTA showed that retinal neuronal thickness and vascular density in superficial and deep layers of the macular zone as well as vascular density in the optic nerve head were progressively decreased from SM to PS and PS + CA (p < 0.05). The aqueous humour levels of C1q, C3, C3b/iC3b, C4, CFB, CFH, C2, C4b, C5 and CFI were significantly higher in high-myopic eyes compared to those in low-myopic eyes. Further subgroup analysis revealed the highest levels of complement components/fragments in the PS + CA group. The intraocular levels of complement factors particularly C3b/iC3b and C4 were negatively correlated with macular zone deep layer retinal thickness and vascular density and optic nerve head vascular density. The expression of C2, C3 and C4 genes was significantly higher in guinea pig eyes with myopic retinal degeneration compared to control eyes.ConclusionsThe intraocular classical pathway and alternative pathway of the complement system are partially activated in pathological myopia. Their activation is related to the degeneration of retinal neurons and the vasculature in the macula and the vasculature in the optic nerve head

Dynamic operation of metal-supported solid oxide electrolysis cells

Symmetric-structure metal-supported solid oxide fuel cells and electrolysis cells (MS-SOFCs, MS-SOECs) offer several advantages over conventional solid oxide cells, including the use of inexpensive materials, high mechanical strength, and rapid ramp-up ability. Aggressive operation of MS-SOCs in fuel cell mode is well-established, including extremely fast start-up, redox tolerance, and imbalanced pressure. Here, we extend dynamic operation to MS-SOCs in SOEC mode with high steam content for both small button cells and a large rectangular cell, including: steam cycling, thermal cycling, redox cycling and power cycling. Steam cycling entailed switching between 3:97 and 50:50 steam:hydrogen ratio. For thermal cycling, the temperature was rapidly varied between 150 °C and 700 °C for 50 cycles. Redox cycling involved switching the steam side gas between 50 % humidified H2 and 50 % humidified N2 for 5 cycles. Power cycling was performed by operating the cell under variable current density, resulting in cell voltage between 1.3 V and 2.8 V. Degradation rates for each testing strategy were compared to a baseline cell, and found to be similar. The excellent tolerance to dynamic operation increases confidence that MS-SOECs will be compatible with dynamic or intermittent renewable resources

Evaluation of Geological Disaster Sensitivity in Shuicheng District Based on the WOE-RF Model

To improve the prevention and control of geological disasters in Shuicheng District, 10 environmental factors—slope, slope direction, curvature, NDVI, stratum lithology, distance from fault, distance from river system, annual average rainfall, distance from road and land use—were selected as evaluation indicators by integrating factors such as landform, basic geology, hydrometeorology and engineering activities. Based on the weight of evidence, random forest, support vector machine and BP neural network algorithms were introduced to build WOE-RF, WOE-SVM and WOE-BPNN models. The sensitivity of Shuicheng District to geological disasters was evaluated using the GIS platform, and the region was divided into areas of extremely high, high, medium, low and extremely low sensitivity to geological disasters. By comparing and analyzing the ROC curve and the distribution law of the sensitivity index, the AUC evaluation accuracy of the WOE-RF, WOE-SVM and WOE-BPNN models was 0.836, 0.807 and 0.753, respectively; the WOE-RF model was shown to be the most effective. In the WOE-RF model, the extremely high-, high-, medium-, low- and extremely low-sensitivity areas accounted for 15.9%, 16.9%, 19.3%, 21.0% and 26.9% of the study area, respectively. The extremely high- and high-sensitivity areas are mainly concentrated in areas with large slopes, broken rock masses, river systems and intensive human engineering activity. These research results are consistent with the actual situation and can provide a reference for the prevention and control of geological disasters in this and similar mountainous areas

FMDV Leader Protein Interacts with the NACHT and LRR Domains of NLRP3 to Promote IL-1β Production

Foot-and-mouth disease virus (FMDV) infection causes inflammatory clinical symptoms, such as high fever and vesicular lesions, even death of animals. Interleukin-1β (IL-1β) is an inflammatory cytokine that plays an essential role in inflammatory responses against viral infection. The viruses have developed multiple strategies to induce the inflammatory responses, including regulation of IL-1β production. However, the molecular mechanism underlying the induction of IL-1β by FMDV remains not fully understood. Here, we found that FMDV robustly induced IL-1β production in macrophages and pigs. Infection of Casp-1 inhibitor-treated cells and NOD-, LRR- and pyrin domain-containing 3 (NLRP3)-knockdown cells indicated that NLRP3 is essential for FMDV-induced IL-1β secretion. More importantly, we found that FMDV Lpro associates with the NACHT and LRR domains of NLRP3 to promote NLRP3 inflammasome assembly and IL-1β secretion. Moreover, FMDV Lpro induces calcium influx and potassium efflux, which trigger NLRP3 activation. Our data revealed the mechanism underlying the activation of the NLRP3 inflammasome after FMDV Lpro expression, thus providing insights for the control of FMDV infection-induced inflammation

Isoalantolactone inhibits IKKβ kinase activity to interrupt the NF‐κB/COX‐2‐mediated signaling cascade and induces apoptosis regulated by the mitochondrial translocation of cofilin in glioblastoma

Abstract Isoalantolactone (IATL), a sesquiterpene lactone compound, possesses many pharmacological and biological activities, but its role in glioblastoma (GBM) treatment is still unknown. The aim of the current study was to investigate the antiglioma effects of IATL and to explore the underlying molecular mechanisms. In the current study, the biological functions of IATL were examined by MTT, cell migration, colony formation, and cell apoptosis assays. Confocal immunofluorescence techniques, chromatin immunoprecipitation, and pull‐down assays were used to explore the precise underlying molecular mechanisms. To examine IATL activity and the molecular mechanisms by which it inhibits glioma growth in vivo, we used a xenograft tumor mouse model. Furthermore, Western blotting was used to confirm the changes in protein expression after IATL treatment. According to the results, IATL inhibited IKKβ phosphorylation, thus inhibiting both the binding of NF‐κB to the cyclooxygenase 2 (COX‐2) promoter and the recruitment of p300 and eventually inhibiting COX‐2 expression. In addition, IATL induced glioma cell apoptosis by promoting the conversion of F‐actin to G‐actin, which in turn activates the cytochrome c (Cyt c) and caspase‐dependent apoptotic pathways. In the animal experiments, IATL reduced the size and weight of glioma tumors in xenograft mice and inhibited the expression of COX‐2 and phosphorylated NF‐κB p65 in the transplanted tumors. In conclusion, the current study indicated that IATL inhibited the expression of COX‐2 through the NF‐κB signaling pathway and induced the apoptosis of glioma cells by increasing actin transformation. These results suggested that IATL could be greatly effective in GBM treatment

The gut microbiome affects response of treatments in HER2‐negative advanced gastric cancer

Abstract Background Common treatments for metastatic/unresectable HER2‐negative gastric cancer include chemotherapy, immune checkpoint inhibitor monotherapy and chemotherapy plus immune checkpoint inhibitor. However, significant drug resistance exists regardless of the treatment regimen. Methods Patients with metastatic/unresectable HER2‐negative gastric/gastroesophageal junction adenocarcinoma were enrolled. All patients were divided into three groups according to the treatment regimen and were further divided into responders and non‐responders according to efficacy evaluation. Metagenomics sequencing were performed to analyze gut microbiome signature of patients receiving different treatments at baseline and throughout treatment. Results One hundred seventeen patients with HER2‐negative advanced gastric or gastroesophageal junction adenocarcinoma receiving chemotherapy alone, anti PD‐1/PD‐L1 immunotherapy alone or combined regimen were included in this study. Microbiome signatures related to clinical response are distinct among the three treatment groups. Among which, 14, 8 and 13 species were significantly different between responders and non‐responders in immunotherapy, immunotherapy plus chemotherapy and chemotherapy group, respectively. Patients with higher relative abundance of Lactobacillus possessed higher microbiome diversity and significantly better response to anti‐PD‐1/PD‐L1 immunotherapy and had a trend to achieve better progression‐free survival. Another cohort of 101 patients has been used as an external validation set to confirm the stability and reliability of these findings. Conclusions Gut microbiome affects response of treatments in HER2‐negative advanced gastric cancer in a treatment‐specific way, immunotherapy plus chemotherapy did not equal to a simple superposition of immunotherapy and chemotherapy. Lactobacillus is expected to become a novel choice as an adjuvant agent in promoting the efficacy of immunotherapy in gastric cancer