Transmission Electron Microscopy Images Research Articles

Innovative Ag@Cu/white sand and polysaccharide based nanocomposites: A simple route to conductive and antibacterial paper coatings

In this work, we presented a simple method for preparing nanocomposite pigments via doping the naturally occurring white sand pigment using silver (Ag) and copper (Cu). The nanocomposites (Ag@WS, Cu@WS, and Ag&Cu@WS) were produced in two suspensions at 25 % and 50 % w/v concentrations, utilizing casein (Cas) and nanostarch (NanoSt) as bio-friendly binders. The prepared nanocomposite pigments were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction crystallography (XRD), and dynamic light scattering (DLS), as well as topographical analysis including scanning electron microscopy (SEM), EDX, and transmission electron microscopy (TEM). The coated paper sheets were characterized using topographical analysis and mechanical, optical, physical, and electrical properties. The antimicrobial activity assay was carried out on the coated paper sheets using the most infectious microbial pathogens. FTIR and XRD analyses confirmed the presence of Cas and NanoSt in the samples. The addition of white sand (WS) and doped nano-metals influenced the crystallographic structure of the polysaccharides. A small amount of Ag, Cu, and Ag&Cu nanoparticles was investigated through EDX. The white sand was a plate structure decorated with spherical Ag, Cu, and Ag&Cu nanoparticles, with an average size of about 147, 105, and 78 nm, as observed from TEM images and DLS. The antimicrobial activity assays revealed that nanocomposite pigment embedded with bimetallic Ag&Cu nanoparticles exhibited a synergistic effect, resulting in enhanced broad-spectrum antibacterial and antifungal activities. The electrical performance of the coated paper was enhanced by using Ag&Cu@WS nanocomposite pigment. Incorporating 50 % Cu@WS into the coating resulted in significant improvements in the mechanical properties of the paper. Specifically, tensile strength increased by 6.3 N/mm, tensile index by 69.06 N m/g, stretching by 1.68 %, tensile energy absorption by 71.4 J/m2, burst strength by 257.75 kPa, and burst index by 2.83 kPa m2/g. Furthermore, incorporating 50 % Ag&Cu@WS increased the opacity to 93.2 % and reduced the roughness of the coated paper by 36 % compared to using 50 % Ag@WS or 50 % Cu@WS alone.

Comparative study of structural, opto-electronic properties of Cs2TiX6-based single halide double perovskite solar cells: computational and experimental approach

This research work represents a comparative study of the structural, optical, and electronic properties of Cs2TiX6 single halide perovskite solar cell (PSC). The entire work has been carried out by experimental work under ambient conditions and followed by the DFT method. Absorbing material structural parameters (lattice constant, shape), and band gap energy can be easily estimated from the DFT approach which can be compared with the result of experimental work. Our study shows Cs2TiBr6 PSC has better band gap energy of 1.80 eV (numerically) and 1.82 eV (experimentally), open circuit voltage 0.58 V, short circuit current 2.55 mA cm−2 for the photovoltaic application. Also, the higher Zeta potential value of Cs2TiBr6 PSC indicates that it has better material stability and is less volatile compared to Cs2TiI6, Cs2TiCl6, and Cs2TiF6 PSCs. TEM images and the SAED pattern of the active layers show a higher degree of crystallite nature of the PSCs.On the other look, investigated PSC materials Cs2TiBr6, Cs2TiI6, Cs2TiCl6, and Cs2TiF6 have shown visible light emission edges at 358 nm, 375 nm, 363 nm, 735 nm wavelength, and the optical performance area of the Cs2TiBr6, Cs2TiI6, Cs2TiCl6, Cs2TiF6 samples is recorded up to 700 nm, 760 nm, 540 nm, and 660 nm wavelength, respectively.

PH-Sensitive blue and red N-CDs for L-asparaginase quantification in complex biological matrices

A novel fluorometric method for the determination of L-asparaginase, an enzyme crucial in cancer therapy and food industry applications, is presented. This sensitive and selective approach utilizes L-asparagine and two pH-sensitive carbon dots (blue-N-CDs and red-N-CDs) as probes. The interaction between L-asparagine and L-asparaginase liberates ammonia, causing an increase in pH. This pH change simultaneously decreases the fluorescence of blue-N-CDs while enhancing the emission of red-N-CDs, enabling ratiometric detection of L-asparaginase. Comprehensive characterization of both carbon dots and investigation of their response mechanism towards L-asparaginase were conducted using ultraviolet–visible spectrophotometry, fluorescence spectroscopy, and transmission electron microscopy (TEM) imaging techniques. The designed approach demonstrates outstanding linearity (20 to 2000 U L-1) and a low detection limit (6.95 U L-1) for L-asparaginase quantification. Moreover, when tested to human serum samples, the detection system exhibits outstanding selectivity and high recovery rates (96.15% to 99.75%) with low standard deviation, underscoring its suitability for practical implementation in clinical diagnostics.

Advancing the hydrogen tolerance of ultrastrong aluminum alloys via nanoprecipitate modification

Ultrastrong metallic alloys, possessing unparalleled load-bearing abilities, are coveted in many sectors, thus attracting growing research efforts. However, these alloys encounter persistent usability challenges posed by hydrogen embrittlement, which causes unpredictable fracture through crack initiation. Due to complex hydrogen-microstructure interactions and their exacerbation under high stress, advances in hydrogen resistance in ultrastrong materials are sparse throughout their long history. Herein, we report a quantum-mechanics-informed strategy for hydrogen tolerance enhancement in ultrafine-grain-hardened Al-Zn-Mg-Cu alloys, approaching their current strength limit of approximately 1 GPa. This method involves the incorporation of hydrogen-absorbing T-phase precipitates into nanograins, to substantially reduce hydrogen coverage at potential crack initiation sites. We demonstrate, via synchrotron radiation X-ray micro-/nano-tomography, scanning transmission electron microscopy and atom probe tomography, that nanoprecipitates successfully withstand shear strains exceeding 1000 and are exploitable essentials for ultra strength-hydrogen synergy, contrasting their often-assumed secondary roles in nanocrystalline alloys due to possible strain-induced dissolution, which has intuitively excluded exploring them as central elements. Our approach potentially inspires new hydrogen-resisting alloys across a broad strength-composition space.

Amine-functionalized cellulose-silica composites for the remediation of hexavalent chromium (Cr IV) in contaminated water

Adsorption method for Hexavalent chromium (Cr(VI) removal from domestic and industrial wastewater is widely desirable due to public health concern of the heavy metal. The purpose of this study was to investigate the evaluation of Cr(VI) adsorption using a novel adsorbent: amine-functionalized cellulose-silica composite derived from banana fibers. We employed the in-situ sol–gel method to create cellulose-silica silane functionalized composites, analyzing them through different characterization techniques such as Attenuated total reflectance- Fourier transform infrared spectroscopy (ATR-FTIR), X-ray Diffraction Analysis (XRD), Thermo gravimetric analysis (TGA)/differential thermogravimetric (DTG), Brunauer–Emmett–Teller (BET), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) techniques. ATR-FTIR depicted key organic constituents in raw banana pseudo stem fibers (BF) and the formation of SiO bonds in BCSiO2 composite, and further enhanced by the grafting of N-[3-(trimethoxysilyl)propyl ethylenediamine (DAPTMS) onto the BC-SiO2 surface in BC-SiO2-DAPTMS. XRD and TGA/DTG analyses revealed changes in crystallinity and thermal stability, while BET analysis showcased altered surface area and pore characteristics in BC-SiO2-DAPTMS (2 %). SEM and TEM imaging provided visual evidence of structural modifications and improved dispersion in BC-SiO2-DAPTMS composites. The impact of composite weight, contact time, and pH on Cr(VI) removal rates was examined, revealing optimal performance at slightly acidic pH 4 value (80.7 %) and enhanced efficiency with increased contact time of 65 min (86.66 %), composite weight of 1 g (82.62 %), and initial concentration was for 0.8 mg/l (80 %). The kinetics and isotherms analyzed using pseudo second order (PSO) and pseudo first order (PFO) models, highlight the composite’s efficiency. The Freundlich model was found to better fit the adsorption isotherm data, while the PSO model described the kinetics more accurately. These insights contribute to optimizing the BC-SiO2-DAPTMS (2 %) composite for efficient Cr(VI) ion removal in water treatment applications.

Microstructure of Gilsocarbon graphite revealed by a correlative study of optical texture and FIB-TEM

Transmission Electron Microscopy (TEM) alongside Polarized Optical Microscopy (POM), is used to investigate the microstructure of nuclear graphite, specifically Gilsocarbon coke, fillers, binders, and flour. Detailed analyses revealed domain structures, domain boundaries, sub-domains and two types of microcracks: intra-domain and inter-domain cracks. Analysis of TEM images, from samples prepared via Focused Ion Beam (FIB), showed domain sizes in coke filler and flour regions ranged from 1 to 3 μm, whereas binder regions had larger domains of up to tens of micrometers, with correspondingly longer Mrozowski cracks. Within these domains, sub-domain boundaries further constrained Mrozowski cracks, resulting in crack lengths significantly shorter than the domain size. Domain boundaries were classified into small-angle and large-angle boundaries based on orientation differences, with large-angle boundaries arising from multiple small-angle transformations facilitated by polygonal microcracks. This microstructural data obtained from virgin Gilsocarbon graphite provides essential inputs for an experimentally informed model predicting the deformation and fracture properties of this material at the micrometer length scale, which may offer improved insights to enhance our understanding of how these properties may evolve under reactor operating conditions.

Biomass-based perovskite/graphene oxide composite for the removal of organic pollutants from wastewater

Water pollution is a critical issue that affects both human health and the environment. Biomass-based LaFeO3 is prepared by the microwave-assisted method using rice straw as a cellulose source. Then LaFeO3/graphene oxide (GO) composite is prepared by ultrasonication to facilitate the perovskite-GO binding. Raman and FTIR spectra of the prepared composite identify the presence of the perovskite, biochar, cellulose and GO oxide phases and proves the surface functional groups interactions. Transmission electron microscope image shows that the GO sheets are homogeneous covered with the perovskite nanoparticles. The adsorption performance of the LaFeO3/GO composite for the removal of methylene blue (MB) and congo red (CR) dyes from aqueous solution is optimized. Adsorption follows pseudo 2nd order kinetic model and Freundlich isotherm, with maximum adsorption capacities of 319.5 and 416.7 mg/g for MB and CR, respectively. These values are higher than those reported for magnetic GO composites, indicating the excellent adsorption ability of the proposed perovskite/GO composite. A thermodynamic study shows that the adsorption of MB is exothermic, while it is endothermic for CR and combines physisorption and chemisorption characteristics for both dyes. The proposed adsorbent shows a good performance in the presence of NaCl interferent, with the possibility of regeneration and efficient successive reuse.

Increasing the Resolution of Transmission Electron Microscopy by Computational Ghost Imaging.

By means of numerical simulations, we demonstrate the innovative use of computational ghost imaging in transmission electron microscopy to retrieve images with a resolution that overcomes the limitations imposed by coherent aberrations. The method requires measuring the intensity on a single pixel detector with a series of structured illuminations. The success of the technique is improved if the probes are made to resemble the sample and the patterns cover the area of interest evenly. By using a simple 8 electrode device as a specific example, a twofold increase in resolution beyond the aberration limit is demonstrated to be possible under realistic experimental conditions.

An Innovative Water Splitting Process for a Sustainable In Situ Hydrogen Generation–Reduction of Nitrobenzenes Catalyzed by a New Bimetallic Nanocatalyst

ABSTRACTIn this research, bimetallic CdNi nanoparticles encapsulated in a magnetic spent coffee ground (Fe3O4@COFF/CdNi) was synthesized as a new nanocatalyst. The structural and chemical characteristics of Fe3O4@COFF/CdNi were comprehensively investigated using various techniques, including FT‐IR, XRD, XPS, TEM, VSM, EDS, TGA, BET, and ICP. Through XRD, XPS analysis, TEM images, and EDS mapping, the presence of CdNi nanoalloys was conclusively established. Fe3O4@COFF/CdNi exhibited remarkable catalytic activity for the hydrogen generation from water using iso‐propanol as a clean sacrificial agent. The high catalytic performance of Fe3O4@COFF/CdNi was attributed to the synergistic cooperative effect of Cd and Ni within CdNi nanoalloys. Interestingly, this process was performed for the in situ generated hydrogen from water to reduce a range of nitrobenzenes simultaneously into the corresponding anilines in high yields (93%–98%). The magnetic and hydrophilic characteristics of Fe3O4@COFF/CdNi facilitated its reusability over five runs. Using water as the most abundant hydrogen source, for the first time for in situ hydrogen generation–reduction of nitrobenzenes without demanding on external light sources or power supplies can be mentioned as a significant milestone of this field of study.

Infectious meningitis. Why are the leptomeninges preferentially involved? Electron microscopic insights.

In infectious meningitis, pathogens preferentially attack the leptomeninges (pia mater and arachnoid) rather than the pachymeninges (dura mater). This study aims to provide ultra-anatomical insights from our extensive collection of electron microscopy images and propose mechanisms, highlighting structures that favor the introduction, adherence, colonization, and proliferation of microorganisms leading to spinal meningitis. Over several years, we analyzed an extensive collection of transmission and scanning electron microscopy images of human spinal meninges captured in our laboratories. Upon examining 378 of those images, we identified potential sites for the iatrogenic or hematogenic introduction and adherence of microorganisms, as well as sites for their colonization and proliferation. These included the outer surface of the spinal dural sac, structures within the epidural space, and the spinal dural sac itself, which comprises compact dura mater with interwoven collagen fibers and tightly bound arachnoid cells. Also, the subdural (extra-arachnoid) compartment, consisting of fragile neurothelial cells prone to rupture under force, formed an acquired spinal subdural space, a new subarachnoid compartment, limited by arachnoid trabeculae, that surrounded the nerve roots and spinal cord and the pia mater. Macrophages, fibroblasts, mast cells, and plasma cells were also observed within the dura mater, arachnoid layer, arachnoid trabeculae, and pia mater. These images illustrate how the characteristics of the meningeal layers could contribute to bacterial adhesion and proliferation at various locations, inducing selective inflammation during (iatrogenic) spinal meningitis. In addition, the images help to explain why magnetic resonance imaging enhancement appears preferentially at specific sites.

Unsupervised machine learning and cepstral analysis with 4D-STEM for characterizing complex microstructures of metallic alloys

Four-dimensional scanning transmission electron microscopy, coupled with a wide array of data analytics, has unveiled new insights into complex materials. Here, we introduce a straightforward unsupervised machine learning approach that entails dimensionality reduction and clustering with minimal hyperparameter tuning to semi-automatically identify unique coexisting structures in metallic alloys. Applying cepstral transformation to the original diffraction dataset improves this process by effectively isolating phase information from potential signal ambiguity caused by sample tilt and thickness variations, commonly observed in electron diffraction patterns. In a case study of a NiTiHfAl shape memory alloy, conventional scanning transmission electron microscopy imaging struggles to accurately identify a low-contrast precipitate at lower magnifications, posing challenges for microscale analyses. We find that our method efficiently separates multiple coherent structures while using objective means of determining hyperparameters. Furthermore, we demonstrate how the clustering result facilitates more robust strain mapping to provide immediate and quantitative structural insights.

Trifunctional Graphene-Sandwiched Heterojunction-Embedded Layered Lattice Electrocatalyst for High Performance in Zn-Air Battery-Driven Water Splitting.

Zn-air battery (ZAB)-driven water splitting holds great promise as a next-generation energy conversion technology, but its large overpotential, low activity, and poor stability for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) remain obstacles. Here, a trifunctional graphene-sandwiched, heterojunction-embedded layered lattice (G-SHELL) electrocatalyst offering a solution to these challenges are reported. Its hollow core-layered shell morphology promotes ion transport to Co3S4 for OER and graphene-sandwiched MoS2 for ORR/HER, while its heterojunction-induced internal electric fields facilitate electron migration. The structural characteristics of G-SHELL are thoroughly investigated using X-ray absorption spectroscopy. Additionally, atomic-resolution transmission electron microscopy (TEM) images align well with the DFT-relaxed structures and simulated TEM images, further confirming its structure. It exhibits an approximately threefold smaller ORR charge transfer resistance than Pt/C, a lower OER overpotential and Tafel slope than RuO₂, and excellent HER overpotential and Tafel slope, while outlasting noble metals in terms of durability. Ex situ X-ray photoelectron spectroscopy analysis under varying potentials by examining the peak shifts and ratios (Co2+/Co3+ and Mo4+/Mo6+) elucidates electrocatalytic reaction mechanisms. Furthermore, the ZAB with G-SHELL outperforms Pt/C+RuO2 in terms of energy density (797Wh kg-1) and peak power density (275.8mW cm-2), realizing the ZAB-driven water splitting.

A combined transport-defect evolution model of microstructure damage in silicon carbide induced by precise irradiation of focused helium ion beams

In this paper, a combined transport-defect evolution multiscale model describing the generation and the evolution of microstructure damage in silicon carbide (SiC) induced by focused helium ion beams is developed. In the proposed model, the transport of helium ions and displaced atoms in the SiC substrate and the generation of point defects are described by the Boltzmann transport equations, while the subsequent defect evolution is characterized by a set of rate equations with the contributions of the modeling of the bubble coalescence as well as the substrate swelling. The validity and superiority of the transport equations are verified by comparing the simulation results with the data from experimental measurements and available simulation methods. The subsurface amorphous profile, onsurface swelling profile, and the spatial and size distribution of helium bubbles in a SiC substrate irradiated by focused helium ion beams are simulated using the proposed multiscale model. The damage morphology simulated by the proposed model is in good agreement with the transmission electron microscopy images at different beam energies and doses. This work provides an effective tool for full-stage modeling of complex evolutionary mechanisms of microstructure damage induced by precise and high-throughput helium irradiation.

Design, Synthesis, Antifungal Evaluation, and Three-Dimensional Quantitative Structure-Activity Relationship of Novel 5-Sulfonyl-1,3,4-thiadiazole Flavonoids.

Plant pathogenic fungi frequently disrupt the normal physiological and biochemical functions of plants, leading to diseases, compromising plant health, and ultimately reducing crop yield. This study aimed to address this challenge by identifying antifungal agents with innovative structures and novel mechanisms of action. We designed and synthesized a series of flavonoid derivatives substituted with 5-sulfonyl-1,3,4-thiadiazole and evaluated their antifungal activity against five phytopathogenic fungi. Most flavonoid derivatives demonstrated excellent antifungal activity against Botrytis cinerea (B. cinerea), Alternaria solani (A. solani), Rhizoctorzia solani (R. solani), Fusarium graminearum (F. graminearum), and Colletotrichum orbiculare (C. orbiculare). Specifically, the EC50 values of 38 target compounds against R. solani were below 4 μg/mL, among which the compounds C13 (EC50 = 0.49 μg/mL), C15 (EC50 = 0.37 μg/mL), and C19 (EC50 = 0.37 μg/mL) had the most prominent antifungal activity, superior to that of the control drug carbendazim (EC50 = 0.52 μg/mL). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of the cellular ultrastructures of R. solani mycelia and cells after treatment with the compound C19 revealed sprawling growth of hyphae, a distorted outline of their cell walls, and reduced mitochondrial numbers. Studying the 3D-QSAR between the molecular structure and antifungal activity of 5-sulfonyl-1,3,4-thiadiazole-substituted flavonoid derivatives could significantly improve conventional drug molecular design pathways and facilitate the development of novel antifungal leads.

PEGylated pH-Responsive Liposomes for Enhancing the Intracellular Uptake and Cytotoxicity of Paclitaxel in MCF-7 Breast Cancer Cells.

This study aimed to develop paclitaxel (PTX)-loaded PEGylated (PEG)-pH-sensitive (SpH) liposomes to enhance drug delivery efficiency and cytotoxicity against MCF-7 breast cancer cells. PTX-loaded PEG-SpH liposomes were prepared using the thin film hydration method. ATR-FTIR compatibility studies revealed no significant interactions among liposome formulation components. TEM images confirmed spherical morphology, stability, and an ideal size range (180-200nm) for improved blood circulation. At pH 5.5, liposomes exhibited increased size and positive zeta potential, indicating pH-sensitive properties due to CHEMS response to the acidic tumor microenvironment. Conversely, at pH 7.4, liposomes showed a slightly larger size (199.25 ± 1.64nm) and a more negative zeta potential (-36.94 ± 0.32mV), suggesting successful PEG-SpH surface modification, enhancing stability, and reducing aggregation. PTX-loaded PEG-SpH liposomes demonstrated high encapsulation efficiency (84.57 ± 0.92% w/w) and drug loading capacity (4.12 ± 0.26% w/w). In-vitro drug release studies revealed accelerated first-order PTX release at pH 5.5 and a controlled zero-order release at pH 7.4. Cellular uptake studies on MCF-7 cells demonstrated enhanced PTX uptake, attributed to mPEG-PCL incorporation prolonging circulation time and CHEMS facilitating PTX release in the tumor microenvironment. Furthermore, PTX-loaded PEG-SpH liposomes exhibited significantly improved cytotoxicity with an IC50 value of 1.107µM after 72-h incubation, approximately 90% lower than plain PTX solution. Stability studies confirmed the robustness of the liposomal formulation under various storage conditions. These findings highlight the potential of PEGylated pH-responsive liposomes as effective nanocarriers for enhancing PTX therapy against breast cancer.

Mitochondria-Targeted Ratiometric KLA-Tweezers for Fluorescence Imaging of Potassium Ions.

Intracellular potassium ions play a crucial role in cellular homeostasis associated with physiological and pathological processes. It is still challenging but definitely crucial to precisely and dynamically image subcellular K+. Herein, the first mitochondria-targeted DNA tweezers (KLA-tweezers) were developed for the fluorescence imaging of mitochondrial K+ with high selectivity and accuracy. The proposed KLA-tweezers consisted of two DNA double-crossover (DX) motifs, a K+-aptamer, and a mitochondria-targeted peptide (KLA) which was conjugated at the rear of DX arms via complementary base pairing. Upon contact with K+, the K+-aptamer experienced a conformational change from an open-chain G-rich sequence to a G-quadruplex with a compact conformation, which was reflected by the Förster resonance energy transfer process between Cy3 and Cy5 labeled at the end of the DX arms. The open and closed states of the tweezers before and after KLA modification were confirmed by gel electrophoresis and fluorescence spectra together with atomic force microscopy (AFM) and transmission electron microscopy (TEM) images, suggesting the KLA assembly had no effect on the morphology change. The proposed tweezers and KLA-tweezers showed low cytotoxicity, excellent selectivity, and good reversibility upon alternating addition of 18-crown-6 and K+. Besides, the KLA-tweezers exhibited outstanding stability and accurate mitochondria location ability. Upon stimulation of ATP or nigericin, intracellular fluorescence imaging of mitochondrial K+ dynamics was successfully achieved. This strategy has broad prospects as a general optical sensing platform for other metal ions or organelles in living cells.

Amplifying Fibre Optic Sensor Signals with Graphene Oxide-Silver Nanostars

This work presents a straightforward yet impactful method to enhance optical fibre sensor signals by integrating silver nanostars (AgNS) with graphene oxide (GO-AgNS) as a sensing material. AgNS were synthesized successfully via a one-step chemical reduction method using hydroxylamine as a reducing agent. The concentration of hydroxylamine was varied (7.2, 3.6, 1.8, and 0.9) x 10−4 %v/v to optimize AgNS formation, with the longest spike of the nanostar observed at lower hydroxylamine concentrations, as confirmed by transmission electron microscopy (TEM). UV-visible measurements revealed the highest peak absorption for AgNS synthesized using 0.9 x 10−4 %v/v hydroxylamine, 0.05 M sodium hydroxide, 0.8 mM silver nitrate, and 0.045 M sodium citrate, with an average length of 352.62 ± 59.72 nm measured from TEM images. GO was synthesized via a modified Hummer’s method and mixed with AgNS at varying ratios (1:5, 1:10, 1:15, and 1:20) to form GO-AgNS coatings for the fibre optic probe. The GO-AgNS coating at a ratio of 1:5 exhibited the highest light absorption intensity, enhancing optical signal by 218% compared to GO-coated and 174% compared to AgNS-coated fibre optic sensors. These findings demonstrate that embedding AgNS onto the GO matrix structure as a sensing material significantly improves sensor performance, suggesting promising applications for super-sensitive, cost-effective, and rapid detection in fibre optic-based sensors.

Synthesis and Characterization of CoFe2O4 Nanoparticles and CoFe2O4@BaTiO3 Nanocomposites for Biomedical Applications

Cobalt ferrite magnetic nanoparticles (CFO) of around 9 nm were synthesized with the solvothermal method. The CFO particles were covered with a barium titanate (BTO) shell at a 1:1 CFO:BTO ratio, via a sol-gel synthesis, to form CFO@BTO nanocomposites. X-Ray Diffraction (XRD) studies reveal the presence of only the expected CFO and BTO phases. Scanning and Transmission Electron Microscopy (SEM, TEM) images show the thorough covering with the BTO shell. Energy-Dispersive X-ray spectroscopy (EDX) mapping was used to analyze the elemental composition of the nanocomposites. Magnetic characterization shows high saturation magnetization and low coercive field at 300 K, suitable for biomedical applications.

Effects of irradiation on interfacial strength and microstructure of double-layer mullite and alumina coating on SiC

Silicon carbide (SiC) ceramics hold great potential for use in nuclear-reactor components due to characteristics such as high-temperature strength and low activation. Despite their resistance against corrosion in harsh environments, they suffer elevated corrosion rates under particle irradiation. Thin anti-corrosion coatings, such as mullite bond layers and alumina top layers, are essential to enhance the irradiation stability of SiC. The objective of this study was to evaluate the irradiation stability of a double-layer coating developed to enhance the corrosion resistance of SiC in nuclear applications. The coating, which comprised a mullite bond layer and an alumina top layer, was applied to a SiC substrate using laser chemical vapor deposition. Irradiation experiments were conducted at 300 °C with 5.1-MeV Si ions up to 10 displacements per atom. To assess the interfacial strength, a novel testing method, called the double-notch shear compression testing method, was developed based on ASTM standards and was implemented using a nanoindenter. This approach enabled precise measurements of the mechanical integrity at the interfaces of the coating under irradiation. The results showed an increase in the interfacial strength at the SiC/mullite and alumina/mullite interfaces with irradiation. Microstructural analysis of the fracture surface through scanning electron microscopy–energy-dispersive X-ray spectroscopy revealed that cracks propagated within the mullite layer, indicating the presence of mullite on the fracture surface. Transmission electron microscopy (TEM) images indicated that a 2-µm-thick transition layer existed at the SiC/mullite interface but not at the alumina/mullite interface. The TEM–electron energy loss spectroscopy suggested that the Al-O bonding structures in the transition layer were changed from tetrahedral (AlO4) to octahedral (AlO6) through irradiation, and this structural transition may directly affect the strength.

Abstract C035: MAGEA6 Oncogene Upregulates MAPK and AMPK Signaling Pathways in Pancreatic Cancer Cells to Promote Survival under Nutrient Stress: Resistance to Glycolysis Inhibition and Increased Susceptibility to Glutamine Depletion

Abstract Introduction: Melanoma-associated antigens (MAGEs) are linked to aggressive disease progression and treatment resistance in many cancers, but their role in pancreatic cancer is not well understood. Our preliminary TCGA data analysis suggested that 10% of pancreatic tumors express MAGEA3/6 and potentially help pancreatic cancer cells survive and grow under nutrient stress. This study aims to uncover the molecular mechanisms of MAGEA3/6 function in pancreatic cancer cell metabolism and disease progression under nutrient-poor conditions. Methods: To understand the role of highly homologous genes MAGEA3 and MAGEA6 in pancreatic cancer, we expressed them in highly glycolytic MIA PaCa-2 pancreatic cancer cells. Cells were then exposed to cancer-related nutritional stressors, including glycolysis inhibition by 2-deoxy-D-glucose (2DG) treatment and glutamine depletion. We analyzed the effect of MAGEA6 expression on cell viability and cell metabolism by Alamar Blue viability assay (BioRad), Seahorse (Agilent), Phenotype MicroArray Mammalian analysis (Biolog), transmission electron microscopy (TEM), and RNA sequencing. To confirm our results, we performed loss-of- function studies in MAGEA3/6-positive cells, including PANC1. Results: We found that, compared to control GFP-expressing cells, MAGEA6-expressing MIA PaCa-2 cells were resistant to glycolysis inhibition with 2-DG. In contrast, they were more susceptible to glutamine depletion, suggesting the important role of MAGEA3/6 in metabolic phenotype and adaptations of pancreatic cancer cells. Further, we showed that MAGEA6-expressing cells exhibited increased ATP production and mitochondrial oxidative phosphorylation, especially under 2DG stress. After 48 hours of 2DG treatment, TEM images revealed significant differences in nuclear, mitochondrial, and ribosomal structures in MAGEA6-cells, further suggesting MAGEA6's role in metabolic adaptation. The Phenotype MicroArray assay demonstrated that α-D-Glucose is the primary nutrient source consumed by both GFP and MAGEA6-expressing cells among the 93 nutrients tested. Additionally, A6 cells utilize Pyruvic Acid as an alternative nutrient source more than GFP cells. To uncover molecular underpinning, we performed RNA sequencing and found that MAGEA6 expression affects transcriptome under glutamine depletion and 2DG treatment. Intriguingly, one of the major differentially regulated biological processes was associated with the upregulation of several signaling pathways, including MAPK and AMPK. Conclusion: Our findings suggest that in pancreatic cancer, MAGEA6 recruits stress and growth factor- dependent MAPK and AMPK pathways to overcome glycolysis inhibition, even in glutamine- depleted conditions, providing a growth advantage. This implies that patients with MAGEA6- positive tumors may benefit from combination therapy targeting metabolism and signaling pathways. Citation Format: Sima Tozandehjani, Barbara Breznik, Klementina Fon Tacer, Miloš Vittori, Juan Sebastian Solano, Sara Uhan. MAGEA6 Oncogene Upregulates MAPK and AMPK Signaling Pathways in Pancreatic Cancer Cells to Promote Survival under Nutrient Stress: Resistance to Glycolysis Inhibition and Increased Susceptibility to Glutamine Depletion [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C035.