Morphological Structure Research Articles

Effects of UV-C exposure on composite materials made of recycled carbon fibers

Carbon fiber-reinforced polymers are widely used in space applications since they combine outstanding mechanical properties with low material density. However, the development of composite components involves raw materials that are becoming increasingly scarce and contributes significantly to carbon emissions during the manufacturing process. Indeed, the fabrication of fibers is energy-intensive and requires very high temperatures, high costs, and usually precursor materials derived from fossil fuels. In addition to the negative environmental impact due to the manufacturing process, there are critical issues related to the disposal of components fabricated using carbon/glass fiber composites. Therefore, the use of efficient recycling strategies becomes necessary, according to economic reasons and legislation. The recycled fibers exhibit different properties from virgin fibers, generally lower, due to adverse effects of the current recycling methods. In this study, we investigated the potential application of recovered carbon fibers in satellite platforms, using recycled fibers from our laboratory obtained with a subcritical solvolysis method that we have previously developed. Composite materials reinforced with recycled and virgin carbon fibers were exposed to UV-C, and the effects of irradiation were analyzed in terms of structural performance, surface morphology, and chemical modifications of the samples. Results were used to evaluate the possibility of effectively using recycled fibers in space applications, without significant loss of performance.

The Effect of Ultrasonication and Delignification Treatment on the Sugar Released Value of Wood

The objective of these research was to study the impact of ultrasonication and delignification pretreatments in several wood species on their easiness for enzymatic hydrolysis, having the potential to be developed as the feedstocks for bioethanol production. Four different wood species from three botanical gardens in Indonesia have been selected, i.e., Gymnostoma sumatranum, Firmiana malayana, Pterocarpus indicus, and Alstonia scholaris, due to their higher sugar released values than a fast-grown tree, Sengon (Paraserianthes falcataria), when all were directly enzymatically hydrolyzed without pretreatment. The sugar released values after ultrasonication and enzymatic hydrolysis were between 3 – 5.5 mg/100 mg wood meal. When delignification pretreatment was performed, the sugar released values were higher than those with ultrasonication, ranging between 4 – 10.2 mg/100 mg wood meal. All the sugar released values after pretreatment were higher than those without pretreatment. Gymnostoma sumatranum was selected as the most potential wood species in this study due to its consistency among the species producing highest sugar released across different treatments. The SEM results showed that there was no significant changes in the morphological structure of the untreated fiber before and after enzymatic saccharification since it still had a complex structure due to the high lignin content. However, after the delignification treatment, the surface morphology of the fiber showed a decrease in the number of pits of the fiber, the surface residual of pits were reduced, parallel lines were more clearly visible, and the fiber structure was damaged with more small holes presented. The surface morphology of the fiber from the wood powder having delignification pretreatment supports the sugar released values which shows that the these values were higher than other treatments due to more recalcitrant substances were degraded, making it was easier for enzymes to break down cellulose. After ultrasonication, the SEM result showed less disrupted cell wall compared to after delignification which confirmed the higher sugar released data with delignification.

UrduAspectNet: Fusing Transformers and Dual GCN for Urdu Aspect-Based Sentiment Detection

Urdu, characterized by its intricate morphological structure and linguistic nuances, presents distinct challenges in computational sentiment analysis. Addressing these, we introduce ”UrduAspectNet” – a dedicated model tailored for Aspect-Based Sentiment Analysis (ABSA) in Urdu. Central to our approach is a rigorous preprocessing phase. Leveraging the Stanza library, we extract Part-of-Speech (POS) tags and lemmas, ensuring Urdu’s linguistic intricacies are aptly represented. To probe the effectiveness of different embeddings, we trained our model using both mBERT and XLM-R embeddings, comparing their performances to identify the most effective representation for Urdu ABSA. Recognizing the nuanced inter-relationships between words, especially in Urdu’s flexible syntactic constructs, our model incorporates a dual Graph Convolutional Network (GCN) layer.Addressing the challenge of the absence of a dedicated Urdu ABSA dataset, we curated our own, collecting over 4,603 news headlines from various domains, such as politics, entertainment, business, and sports. These headlines, sourced from diverse news platforms, not only identify prevalent aspects but also pinpoints their sentiment polarities, categorized as positive, negative, or neutral. Despite the inherent complexities of Urdu, such as its colloquial expressions and idioms, ”UrduAspectNet” showcases remarkable efficacy. Initial comparisons between mBERT and XLM-R embeddings integrated with dual GCN provide valuable insights into their respective strengths in the context of Urdu ABSA. With broad applications spanning media analytics, business insights, and socio-cultural analysis, ”UrduAspectNet” is positioned as a pivotal benchmark in Urdu ABSA research.

Seismic performance of recentering energy dissipation bracing with pendulum in prefabricated steel frame structure systems

This research introduces the recentering energy dissipation bracing with a pendulum in prefabricated steel frame (REBP-PSF) structures. The primary objective of this study is to mitigate potential severe damage to steel frames during seismic events and to expedite postearthquake rehabilitation. This innovative system harnesses energy dissipation through friction between structural members and facilitates recentering through the cable pretensioning force. Consequently, this may make postearthquake repairs minimal or even unnecessary. Three REBP-PSF structures and a prefabricated steel frame with cantilever beam splices (PSF-CBS) were meticulously modeled using the ABAQUS finite element method to evaluate the seismic performance of this novel system. The study investigated the effects of pretensioning parameters and varied structural morphologies on seismic performance metrics, including failure modes, hysteresis performance, energy dissipation capacity, and residual displacements. This paper introduced a simplified method to simulate the restoring force model of REBP using the connection element method. Subsequently, a model for the REBP-RSF overall structure was established, enabling nonlinear dynamic time-history analysis, which was then compared with the rigid steel frame (RSF) structure. The results showed that the REBP-PSF structure outperformed the PSF-CBS in terms of initial stiffness, yield load, ultimate load, and energy dissipation capability. The bearing and energy dissipation capacities of the REBP-PSF structure were enhanced by augmenting the cable pretensioning force within this structure. The proposed connection element method could accurately simulate the hysteretic behavior of REBP. Compared with the RSF structure, the REBP-RSF demonstrated superior seismic performance, characterized by small story drift and residual displacements during seismic activities. Furthermore, a notable augmentation was observed in the lateral stiffness and torsional rigidity of the proposed structure.

Effect of surface functional groups of polystyrene micro/nano plastics on the release of NOM from flocs during the aging process

Currently, the hidden risk of microplastics in the coagulation process has attracted much attention. However, previous studies aimed at improving the removal efficiency of microplastics and ignored the importance of interactions between microplastics and natural organic matter (NOM). This study investigated how polystyrene micro/nano particles impact the release of NOM during the aging of flocs formed by aluminum-based coagulants Al13 and AlCl3. The results elucidated that nano-particles with small particle sizes and agglomerative states are more likely to interact with coagulants. After 7 years of floc aging, the DOC content of the nano system decreased by more than 40%, while the micron system did not change significantly. During coagulation, the benzene rings in polystyrene particles form complexes with electrophilic aluminum ions through π-bonding, creating new Al-O bonds. NOM tends to adsorb at micro/nano plastic interfaces due to hydrophobic interactions and conformational entropy. In the aging process, the structure of PS-Al13 or PS-AlCl3 flocs and the functional groups on the surface of micro/nano plastics control the absorption and release of organic matter through hydrophobic, van der Waals forces, hydration, and polymer bridging. In the system with the addition of nano plastics, several DBPs such as TCAA, DCAA, TBM, DBCM and nitrosamines were reduced by more than 50%. The reaction order of different morphological structures and surface functional groups of microplastics to Al13 and AlCl3 systems is aromatic C-H > C-OH > C-O > NH2 > aromatic CC > aliphatic C-H and C-O>H-CO> NH2 >C-OH> aliphatic C-H. The results provided a new sight to explore the effect of micro/nano plastics on the release of NOM during flocs aging.

Eco-Friendly Poly (Butylene Adipate-co-Terephthalate) Coated Bi-Layered Films: An Approach to Enhance Mechanical and Barrier Properties.

In this research work, a coated paper was prepared with poly (butylene adipate-co-terephthalate) (PBAT) film to explore its use in eco-friendly food packaging. The paper was coated with PBAT film for packaging using hot pressing, a production method currently employed in the packaging industry. The coated papers were evaluated for their structural, mechanical, thermal, and barrier properties. The structural morphology and chemical analysis of the coated paper confirmed the consistent formation of PBAT bi-layered on paper surfaces. Surface coating with PBAT film increased the water resistance of the paper samples, as demonstrated by tests of barrier characteristics, including the water vapor transmission rate (WVTR), oxygen transmission rate (OTR), and water contact angle (WCA) of water drops. The transmission rate of the clean paper was 2010.40 cc m-2 per 24 h for OTR and 110.24 g m-2 per 24 h for WVTR. If the PBAT-film was coated, the value decreased to 91.79 g m-2 per 24 h and 992.86 cc m-2 per 24 h. The hydrophobic nature of PBAT, confirmed by WCA measurements, contributed to the enhanced water resistance of PBAT-coated paper. This result presents an improved PBAT-coated paper material, eliminating the need for adhesives and allowing for the fabrication of bi-layered packaging.

Fabrication of CZTS Thin Film on Flexible Cu-Foil Substrate by Two-Stage Process

In this research, CZTS thin films grown on flexible Cu-foil with varying sulfurization times. Various characterization methods were employed, including X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), optical transmission, and photoluminescence (PL) measurements. Distinctive diffraction peaks characteristic of the kesterite CZTS phase were observed in the XRD analysis, occurring around at 2θ= 28.45° (112), 47° (220/204), and 56° (312/116). Additionally, some secondary phases such as Cu2S and SnS were identified. Raman spectroscopy confirmed the presence of the kesterite phase, with a prominent peak detected at approximately ~336 cm-1, attributed to sulfur atom vibrations within the kesterite structure. Apart from CZTS structure, minor peaks suggesting the presence of the Cu2SnS3 (CTS) phase was detected. EDX analysis revealed compositions with Cu-poor content and Zn-rich content across all samples, with slight variations in sulfurization dwell times affecting the chemical composition. SEM imaging at different magnifications showed alterations in surface morphology and grain structures. Films sulfurized for 30 s and 60 s displayed a granular structure morphology, while extending the dwell time to 120 s resulted in a more compact surface morphology. Optical band gap values ranged between 1.57 and 1.60 eV. PL measurements consistently exhibited strong PL emission around 1.25 eV for all samples, attributed to various transitions within the CZTS structure. The absence of observable band-to-band transitions in the PL measurements indicated the presence of intrinsic defect levels and recombination centers within CZTS. Overall, it was demonstrated in this study that CZTS thin films can be produced on flexible Cu-foils with short sulfurization times, thereby expanding the application areas of CZTS thin-film solar cells.

Green synthesis of copper and iron nanoparticles from extracts of eucalyptus with their antimicrobial activities

Eco-friendly iron and copper nanoparticles were synthesized using masquerade and eucalyptus leaves extract as a reducing and stabilizing agents. Iron chloride heptahydrate (FeCl2.7H2O) and Copper sulphatepenta hydrate (CuSO4.5H2O) as metal precursors. It was characterized using UV visible, FTIR, XRD and SEM analysis. The UV result shows the highest peaks at 500 and 600 nm for iron and copper respectively. This is due to the surface plasma vibration of the phytochemical constituents present in the extract. FTIR shows presence of alkanoids and triterpenes, SEM shows the spherical granular with no well-defined morphology and mono dispersed structures for iron and copper nanoparticles respectively. It shows good antibacterial activity when tested against Escherichia-coli and Pseudomonas auredinosa (gram- negative), Staphylococcus aureus and Klebsella pneumonia (gram-positive).

Shaping the Future of the Neurotransmitter Sensor: Tailored CdS Nanostructures for State-of-the-Art Self-Powered Photoelectrochemical Devices.

Semiconductor-based photoelectrochemical (PEC) test protocols offer a viable solution for developing efficient individual health monitoring by converting light and chemical energy into electrical signals. However, slow reaction kinetics and electron-hole complexation at the interface limit their practical application. Here, we reported a triple-engineered CdS nanohierarchical structures (CdS NHs) modification scheme including morphology, defective states, and heterogeneous structure to achieve precise monitoring of the neurotransmitter dopamine (DA) in plasma and noninvasive body fluids. By precisely manipulating the Cd-S precursor, we achieved precise control over ternary CdS NHs and obtained well-defined layered self-assembled CdS NHs through a surface carbon treatment. The integration of defect states and the thin carbon layer effectively established carrier directional transfer pathways, thereby enhancing interface reaction sites and improving the conversion efficiency. The CdS NHs microelectrode fabricated demonstrated a remarkable negative response toward DA, thereby enabling the development of a miniature self-powered PEC device for precise quantification in human saliva. Additionally, the utilization of density functional theory calculations elucidated the structural characteristics of DA and the defect state of CdS, thus establishing crucial theoretical groundwork for optimizing the polymerization process of DA. The present study offers a potential engineering approach for developing high energy conversion efficiency PEC semiconductors as well as proposing a novel concept for designing sensitive testing strategies.

Influence of Herba Houttuyniae added to fodder on the morphological structure of the intestinal tract, the digestive enzymes, the intestinal flora, and immune function of koi carp (Cyprinus carpio) infected with Aeromonas veronii.

This study investigated whether adding Herba Houttuyniae to feed can improve intestinal function and prevent diseases for koi carp (Cyprinus carpio) infected with Aeromonas veronii. There was a total of 168 koi carp with an average body length of (9.43 ± 0.99) cm and an average body weight of (26.00 ± 11.40) g. The K group was the control group fed with basal feed, while the C group was fed with feed with a H. houttuyniae content of six per thousand. After 14days of feeding, the fish were fasted for a day and then intraperitoneally injected with A. veronii for artificial infection, injection dose is 0.2mL, and the concentration is 1 × 107CFU/mL. Samples were collected from the two groups on days 0, 1, 2, and 4. The fold height, intestinal villus width, and muscle layer thickness in the gut of the koi carp were measured. In addition, on day 4, the activities of trypsin, α-amylase, and lipase in the gut were determined, and the intestinal flora of the carp in both groups was tested. The results showed that on the second and fourth days of sampling, the fold height and muscle layer thickness in the C group were significantly higher than those in the K group (P < 0.05). The villus width in the C group was slightly higher than that in the K group, but the difference was not significant (P > 0.05). Microscopic observation revealed that the intestinal structure of the carp in the C4 (day 4 in C group) group was more intact than that in the K4 (day 4 in K group) group. Moreover, the activities of trypsin, α-amylase, and lipase in the foregut and midgut in the C4 group were higher than those in the K4 group (P < 0.05). The activities of trypsin and α-amylase in the hindgut in the C4 group were higher than those in the K4 group (P < 0.05). Furthermore, beneficial bacteria, especially those in the genus Cetobacterium, were more abundant in the intestinal tract of the carp in the C4 group compared to the K group. In addition, comparisons and tests of IL-4 and IL-10 in the intestines of the fish in both groups demonstrated that the H. houttuyniae added to feed enhanced the immune function of the fish intestines after bacterial attack. In conclusion, for koi carp infected with A.veronii, adding H. houttuyniae to their feed not only improves the activity of digestive enzymes and the morphological structure of the intestine but also optimizes the beneficial intestinal microbiota, thereby protecting the intestinal tract.

Photo-catalytic dye degradation potentials of Ag-Pd bimetallic nanoparticles synthesized from Vitex negundo.

Plant extracts are a great alternative to synthesizing nanoparticles of different metals and metal oxides. This green synthesis method has opened up numerous possibilities in various scientific domains. In present study, Leaf extract from Vitex negundo is a non-deciduous, long-lasting shrub from the Verbenaceae family is used as capping and reducing agents for the synthesis of silver and palladium nanoparticles. The characterization study UV-vis spectrophotometer analysis showed absorbance value around 320nm which confirming that Ag-Pd nanoparticles have been successfully obtained. Further, SEM is used to investigate the morphology of Ag-Pd NPs, which revealing their spherical and rod-like configuration, aggregation, and the size of the particles are obtained between 50 and 100nm. The successful synthesis of Ag-Pd NPs was further confirmed by the EDAX chart, which displayed the peak of Ag and Pd at bending energies between 0.5 and 1.5keV. According to the quantitative study, Ag and Pd ions found about 5.24 and 13.28%, respectively. In addition, surface studies with TEM confirming that synthesized Ag-Pd NPs are predominates with spheres structure morphologies, with sizes averaging 11.20nm and ranging from 10 to 20nm. Further, Ag-Pd nanoparticles was applied as potential photocatalyst materials to degrade methylene blue dye and found about 85% of the degradation efficiency within 150min of the sunlight exposure thus could be used as catalyst to removal of hazardous organic dye molecules.

Microstructure and surface morphology change of hydrogenated diamond-like carbon coating with gradient Cr and Si under high temperature and high pressure

A series of annealing treatments were designed to investigate the microstructure structure and surface morphology of hydrogenated diamond-like carbon coating with gradient Cr and Si (DCrSi) in different environments (argon & isostatic pressure) at different temperatures (400°C, 500°C, and 600°C). The pressure effect on the stability of DCrSi coatings was deduced from the analysis of the microstructure structure and surface morphology by using scanning electron microscopy (SEM), surface roughness test, and Raman spectroscopy. The experiment results show that no apparent change to the layer structure can be found in the argon annealed and HIPped coatings. Similar to argon annealed coatings, with increasing HIPping temperature, the surface roughness of coatings increases, and the sp3 content of the coatings reduces. The relatively low roughness of the HIPped surfaces compared with the argon annealed ones could be attributed to the delayed transformation from sp3 carbon bonding to sp2 carbon bonding (i.e., graphitization) by high pressure. Compared with Si-free DCr coating, for Si-containing DCrSi coatings, Si bonded with C from broken C-H bonding and C-C bonding to form SiC quasi compound. Adding silicon into DLC can increase the density of the coatings.

Geotourism of Telomoyo Volcano complex: an in-depth analysis for future development

Indonesia is located between the three world tectonic plates, the Eurasian Plate, the Indo-Australian Plate and the Pacific Plate. The collision of these three plates creates a series of volcanoes and tectonics activity in various regions, especially the subduction of the Indo-Australian Plate in southern Java. This subduction forming a row of tertiary-aged volcanoes in the south of the island of Java and quaternary in the central part of the island of Java. One of the Quaternary Volcanoes on the island of Java that is extends in a northwest-southeast, the volcanoes are Ungaran - Telomoyo - Merbabu - Merapi. The use of the geotourism analysis method is used to develop the existing geotourism potential in the Telomoyo Volcano Complex by carrying out a geodiversity inventory carried out through field activities to collect geological component data in the research area. The data collected is minerals, rocks, geological and morphological structures or landscapes that include several stages of work include categorization, assessment, evaluation, clustering and determination of geodiversity. This work is accomplished by identifying geoheritage to increase geological diversity into geological heritage through the stages of determining geodiversity and then classified to determine the status, value, meaning and function of geoheritage. The score ranking carried out to determine the geoheritage ranking by comparing the geotourism of the research location with the geotourism of other locations. The Telomoyo Volcano Complex holds a variety of unique and interesting geological phenomena so it had a promising geological conservation-based tourism potential. However, the lack of public knowledge about the potential for geology-based tourism or geotourism has caused the development of this tourism potential to be less than optimal and less desirable. Education, development and good management of the tourism sector are needed so that the potential of geotourism can be recognized by the wider community and can have a good impact, especially for the surrounding community, especially in the economic field.

Adherence of p-Terphenyl (PTP) film on the dichroic filter used for the X-ARAPUCA device

The adherence of the p-Terphenyl film to the substrate in the X-ARAPUCA dichroic filter is directly correlated with the long-term efficiency and durability of this device. This study presents the results of different cleaning methods established to analyze their contributions to the film's adherence to the substrate. The samples underwent analysis of their crystalline and morphological structure using XRD and AFM techniques. Three distinct techniques were employed in the adherence tests: ultrasonic bath, scratch test, and cryogenic immersion method with turbulence, as these devices will be submerged in liquid argon in the DUNE experiment.Results suggest that the deposited PTP layer exhibits a monoclinic crystalline structure, with topography revealing percolated planar grains and roughness ranging from 13 nm to 18 nm. The various adherence techniques employed yielded consistent results, highlighting the standard cleaning process involving Soap + H2O + N2 + Kiln as the preferred method.

Morphological structure and mechanical properties of a nucleated Polyoxymethylene (POM) homopolymer resin processed under conventional injection molding conditions

When injection molding semi-crystalline polymers, it is known that the resulting morphological and mechanical properties are strongly dependent on the processing conditions. Selectively influencing the performance of the final part as early as during processing is of great interest for industrial applications. To investigate the processing-structure-property correlation for a POM hompolymer resin, tensile specimens were manufactured under conventional injection molding conditions following a Design of Experimets (DoE). Morphological characterization was carried out by microscopy and X-ray measurements. Crystallinity was also measured by differential scanning calorimetry (DSC). Additionally, the (fracture) mechanical behaviour of the samples was assessed. Influences of the processing parameters on the crystalline structure and orientations within the material were identified. Furthermore, tensile tests were found to be sensitive to changes in morphology and processing, whereas the fracture behaviour did not change significantly despite the structural changes within the samples.

Experimental study on the coupled flow field and thrust characteristics of tail cavity and jet

During the launch process of underwater vehicles, a tail cavity is formed at the bottom, which plays a crucial role in the engine ignition stage. The flow state within this tail cavity significantly impacts the engine's operational efficiency. Moreover, the evolution of the tail cavity and jet coupling, along with hydrodynamic characteristics, influences the motion attitude of the vehicle. This article delves into the effects of initial tail cavity length, Froude number, and pressure ratio on cavity morphology and hydrodynamic characteristics, utilizing water tunnel experiments to explore these dynamics at the vehicle's bottom. The experimental findings suggest that while the length of the initial tail cavity influences the jet's coupling mode, it does not significantly affect the cavity's ultimate morphological evolution. A larger initial cavity scale correlates with a lower initial pressure peak following nozzle activation; similarly, an increase in the Froude number leads to a decrease in the initial pressure peak. When the cavity morphology remains intact, the pressure pulsation amplitude and frequency are relatively low. In contrast, partially broken cavities and pulsating foam cavities differ in morphological structure and peak internal pressure oscillations, though their pressure pulsation frequencies are similar. During the initial phase of nozzle activation, the thrust produced by the nozzle plays a more significant role than the bottom thrust. Notably, in the initial phase of nozzle activation, the nozzle-generated thrust is more influential than the bottom thrust. The thrust pulsations from pulsating foam cavities are especially strong, with peak values surpassing the initial peak thrust. These insights offer a new insight on the dynamic behavior of underwater vehicles, crucial for refining engine startup strategies.

Research on the performance of porous ZIF materials in lithium-ion batteries

Porous materials have attracted more and more attention in the application of lithium-ion batteries (LIBs), which can improve their performance. Herein, a porous zeolite imidazolate skeleton structure material (ZIF-8@ZIF-67) was manufactured by the two-step synthesis approach. Simultaneously, its morphology structure, pore size, and composition were characterized. The ZIF-8@ZIF-67 was used for the negative electrode material to construct the LIBs to test the performance. The test results show that ZIF-8@ZIF-67 can be used as the electrode material to enhance the capacity and cycling property of LIBs. This investigation provides an avenue for the application of porous materials in LIBs.

Impact of different NaOH treatments on biocellulose properties from coconut water fermented by Lentilactobacillus parafarraginis

Background: Biocellulose is a natural polymer produced by bacteria with distinct physicochemical properties, although it has a chemical composition identical to plant cellulose. Before use, biocellulose was purified by chemical treatment to increase its properties. Objective: The study aimed to evaluate biocellulose properties using NaOH solution as a purification agent. Method: After harvesting, all samples were purified using NaOH of 0.25 M (BC0.25), 0.5 M (BC0.5), and 1 M (BC1) and determined for their properties, such as mechanical strength, swelling degree, water vapour transmission, and moisture content. Analysis of scanning electron microscope (SEM) images and Fourier Transform Infrared Spectroscopy (FTIR) spectra were also performed for characterisation. Result: BC0.5 exhibited the highest tensile strength of 15.38±0.45 MPa and elongation at a break of 38.40±0.58%. BC1 had the highest swelling degree of 131.24±0.70%, water vapour transmission of 400.00±0.36 g/m2, and moisture content of 6.44±0.14%. Nevertheless, there were slight alterations in morphological structure and spectral peaks because of the high concentration of NaOH. Conclusion: The use of NaOH treatment of 0.5 M in biocellulose purification removed more contaminants and resulted in better properties than other concentrations.

Synthesis of biomass nitrogen-doped catalysts and their electrocatalytic performance in fuel cells

At present, biomass materials have the characteristics of low cost, stability, and relatively high activity, which is expected to replace platinum-based (Pt) materials as cathode catalysts. In this paper, Zn, Fe-N-C catalyst materials and Fe-N-C catalyst were composited by high-temperature calcination. Their crystal and morphological structures were featured by X-ray diffraction instruments (XRD) and scanning electron microscopy (SEM). Their activity and stability to oxygen reduction were tested by an electrochemical workstation, and it was found that Zn, Fe-N-C catalyst materials had the best performance. The investigation of this paper can furnish an effective method for oxygen reduction reaction catalysts.

Cardiac Sodium Channel Nav1.5 Arg222Gln Variant Induces a Sex-Specific Arrhythmia and Alters Mitochondrial Function

Introduction: Encoded by the SCN5A gene, cardiac Nav1.5 sodium channels initiate the action potential to trigger a heartbeat. As the predominant sodium channel in the heart, variants can have devastating consequences, leading to potentially lethal arrhythmias. With the gain of function arginine to glutamine (Arg222Gln) variant in Nav1.5, patients develop intermittent arrhythmias and dilated cardiomyopathy. The stress induced by chronic arrhythmias can trigger adverse metabolic reprogramming, exacerbating the underlying condition. We have generated a murine model harboring the human Arg222Gln variant where we observe that only males produce a clear observable arrhythmia. We hypothesize that the maladaptive metabolic response to the arrhythmia caused by the Arg222Gln variant maybe be a potential link to the sex differences. Methods: The human exon containing the Arg222Gln mutation was knocked into a murine model under the endogenous SCN5A promoter. Cellular metabolism (oxygen consumption) was measured using primary adult mouse cardiomyocytes (CMs) with the Seahorse XFe analyzer. Mitochondrial membrane potential was measured using ratiometric JC-1 dye and imaged on a scanning confocal microscope. Heart tissues were diced into 1mm3 cubes and fixed to perform serial block face electron microscopy to obtain 3D structure of mitochondria and mitochondrial morphology. Western blots were used to detect protein levels. Results: Basal respiration of CMs were unchanged, however the maximal respiratory capacity of Arg222Gln males was significantly lower (116.9±13.5pmol O2/min, p&lt;0.05) compared to WT males (407.3±16.4pmol O2/min). There were no differences between WT females (451.4±22.4pmol O2/min) and Arg222Gln females (463.2±33.7pmol O2/min). JC-1 dye revealed that the Arg222Gln males (0.6213±0.0172 red/green ratio, p&lt;0.001) have significantly lowered mitochondrial polarization compared to WT males (0.7550 ±0.0257). There were no differences between WT females (0.6236±0.0154) and Arg222Gln females (0.6466±0.0139). Arg222Gln males have reduced mitochondria area (1.155±0.052μm2, p&lt;0.05) compared to WT males (1.332±0.060μm2) and are more fragmented (p&lt;0.05). Electron transport chain complex protein levels and mitochondrial biomass measured by voltage dependent anion channel protein levels remain unchanged between WT males and Arg222Gln males (P&gt;0.05). The ratio of phosphorylated dynamin related (DRP) / total DRP protein levels were significantly higher in Arg222Gln males compared to WT males, indicative of mitochondrial fission (p&lt;0.05). Conclusion: We demonstrate evidence of a mitochondrial dysfunction in a murine model of arrhythmia caused by a gain of function Nav1.5 variant, adversely affecting overall cellular metabolism and mitochondrial quality. Our data suggests that the difference in metabolic reprogramming could play a role in the cardioprotection against arrhythmia in Arg222Gln females or explain why Arg222Gln males are severely affected by the arrhythmia. Future experiments will aim to elucidate how the difference in sex affects cardiac metabolism in the context of Arg222Gln Nav1.5 variant. This work was supported by a Canadian Institutes of Health Research Project Grant, the SickKids Foundation through the Curtis Joseph and Harold Groves Chair in Anesthesia and Pain Medicine (JTM) and the Department of Anesthesiology and Pain Medicine, University of Toronto through a Merit Award (JTM). TYTL is supported by the CIHR Canadian Graduate Scholarship — Doctoral Award. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.