Search Results (165)

The development of high-speed computers and electronic memories, high-frequency communication networks, electroluminescent and photovoltaic devices, flexible displays, and more requires new materials with unique properties, such as a low dielectric constant, an adjustable refractive index, high hardness, thermal resistance, and processability. SiOC coatings possess a number of desirable properties required by modern technologies, including good heat and UV resistance, transparency, high electrical insulation, flexibility, and solubility in commonly used organic solvents. Chemical vapor deposition (CVD) is a very useful and convenient method to produce this type of layer. In this article we present the results of studies on SiOC coatings obtained from tetramethylcyclotetrasiloxane in a remote hydrogen plasma CVD process. The elemental composition (XPS, EDS) and chemical structure (FTIR and NMR spectroscopy-¹³C, ²⁹Si) of the obtained coatings were investigated. Photoluminescence analyses and ellipsometric and thermogravimetric measurements were also performed. The surface morphology was characterized using AFM and SEM. The obtained results allowed us to propose a mechanism for the initiation and growth of the SiOC layer. Full article

Enhancing the safety of lithium-ion batteries (LIBs) by replacing flammable electrolytes is a key challenge. Ionic liquid (IL)-based electrolytes are considered an interesting alternative due to their thermal and chemical stability, high voltage stability window, and tunable properties. This study investigates the electrochemical behavior of two newly synthesized ILs, comparing them to conventional alkyl carbonate-based electrolytes. Nitrogen-doped carbon silicon oxycarbide (NC-SiOC), used as the active material in negative electrodes, was combined with two polymeric binders: poly(acrylic acid) (PAA) and poly(acrylonitrile) (PAN). NC-SiOC/PAN electrodes exhibited a significantly higher initial charge capacity—approximately 25–30% greater than their PAA-based counterparts in the first cycle at 0.1 A g⁻¹ (850–990 mAh g⁻¹ vs. 600–700 mAh g⁻¹), and demonstrated an improved initial Coulombic efficiency (67% vs. 62%). Long-term cycling stability over 1000 cycles at 1.6 A g⁻¹ retained 75–80% of the initial 0.1 A g⁻¹ capacity. This outstanding performance is attributed to the synergistic effects of nitrogen-rich carbonaceous phases within the NC-SiOC material and the cyclized-PAN binder, which facilitate structural stability by accommodating volumetric changes and enhancing solid electrolyte interphase (SEI) stability. Notably, despite the lower ionic transport properties of the IL electrolytes, their incorporation did not compromise performance, supporting their feasibility as safer electrolyte alternatives. These findings offer one of the most promising electrochemical performances reported for SiOC materials to date. Full article

In most commercial lithium-ion batteries, graphite remains the primary anode material. However, its theoretical specific capacity is only 372 mAh∙g⁻¹, which falls short of meeting the demands of high-performance electronic devices. Silicon anodes, despite boasting an ultra-high theoretical specific capacity of 4200 mAh∙g⁻¹, suffer from significant volume expansion (>300%) during cycling, leading to severe capacity fade and limiting their commercial viability. Currently, silicon-based polymer-derived ceramics have emerged as a highly promising next-generation anode material for lithium-ion batteries, thanks to their unique nano-cluster structure, tunable composition, and low volume expansion characteristics. The maximum capacity of the ceramics can exceed 1000 mAh∙g⁻¹, and their unique synthesis routes enable customization to align with diverse electrochemical application requirements. In this paper, we present the progress of silicon oxycarbide (SiOC), silicon carbonitride (SiCN), silicon boron carbonitride (SiBCN) and silicon oxycarbonitride (SiOCN) in the field of LIBs, including their synthesis, structural characteristics and electrochemical properties, etc. The mechanisms of lithium-ion storage in the Si-based anode materials are summarized as well, including the key role of free carbon in these materials. Full article

Nickel (Ni)-based catalysts, prepared by pyrolyzing Ni-containing polydimethylsiloxane (Ni-PDMS), were evaluated for their activity in the dry reforming of methane (DRM) reaction. The pyrolyzed PDMS support was found to be largely microporous, and the active nickel particles were nano-sized but were not dispersed evenly in the resulting catalysts. The catalysts were prepared with 0 wt%, 2 wt%, 4 wt%, and 6 wt% Ni in PDMS prior to pyrolysis. The resulting catalysts demonstrated notable activity in the DRM reaction, comparable to many of those described in the published literature. The catalyst with 6 wt% Ni (prior to pyrolysis) displayed the highest conversion of methane (47%) and the lowest loss of activity (9.8%) over 11 h of continuous operation. This research was successful in exploring novel polymer-derived catalysts, specifically pyrolyzed Ni-PDMS catalysts, in the dry reforming of methane (DRM) reaction. Full article

Recycled wood fiber (RWF) obtained through the multi-stage processing of waste wood serves as an eco-friendly green construction material, exhibiting lightweight, porous, and high toughness characteristics that demonstrate significant potential as a cementitious reinforcement, offering strategic advantages for environmental protection and resource recycling. In this study, high-performance sulfoaluminate cement (SAC)-RWF composites prepared by modifying RWFs with nano-silica (NS) and a silane coupling agent (KH560) were developed and their effects on mechanical properties, shrinkage behavior, hydration characteristics, and microstructure of SAC-RWF composites were systematically investigated. Optimal performance was achieved at water–cement ratio of 0.5 with 20% RWF content, where the KH560-modified samples showed superior improvement, with 8.5% and 14.3% increases in 28 d flexural and compressive strength, respectively, compared to the control groups, outperforming the NS-modified samples (3.6% and 8.6% enhancements). Both modifiers improved durability, reducing water absorption by 6.72% (NS) and 7.1% (KH560) while decreasing drying shrinkage by 4.3% and 27.2%, respectively. The modified SAC composites maintained favorable thermal properties, with NS reducing thermal conductivity by 6.8% through density optimization, whereas the KH560-treated specimens retained low conductivity despite slight density increases. Micro-structural tests revealed accelerated hydration without new hydration product formation, with both modifiers enhancing cementitious matrix hydration product generation by distinct mechanisms—with NS acting through physical pore-filling, while KH560 established Si-O-C chemical bonds at paste interfaces. Although both modifications improved mechanical properties and durability, the KH560-modified SAC composite group demonstrated superior overall performance than the NS-modified group, providing a technical pathway for developing sustainable, high-performance recycled wood fiber cement-based materials with balanced functional properties for low-carbon construction applications. Full article

Silicon oxycarbide coatings are the subject of research due to their exceptional optical, electronic, anti-corrosion, etc., properties, which make them attractive for a number of applications. In this article, we present a study on the synthesis and characterization of thin SiOC:H silicon oxycarbide films with the given composition and properties from a new organosilicon precursor octamethyl-1,4-dioxatetrasilacyclohexane (²D₂) and its macromolecular equivalent—poly(oxybisdimethylsily1ene) (POBDMS). Layers from ²D₂ precursor with different SiOC:H structure, from polymeric to ceramic-like, were produced in the remote microwave hydrogen plasma by CVD method (RHP-CVD) on a heated substrate in the temperature range of 30–400 °C. SiOC:H polymer layers from POEDMS were deposited from solution by spin coating and then crosslinked in RHP via the breaking of the Si-Si silyl bonds initiated by hydrogen radicals. The properties of SiOC:H layers obtained by both methods were compared. The density of the cross-linked materials was determined by the gravimetric method, elemental composition by means of XPS, chemical structure by FTIR spectroscopy, and NMR spectroscopy (¹³C, ²⁹Si). Photoluminescence analyses and ellipsometric measurements were also performed. Surface morphology was characterized by AFM. Based on the obtained results, a mechanism of initiation, growth, and cross-linking of the CVD layers under the influence of hydrogen radicals was proposed. Full article

Most women with ovarian cancer (OC) develop resistance to platinum chemotherapy, posing a significant challenge to treatment. Matrix metalloproteinase 3 (MMP3) is overexpressed in High-Grade Serous Ovarian Cancer (HGSOC) and is associated with poor survival outcomes; however, its role in platinum resistance remains underexplored. We evaluated the baseline and cisplatin-induced MMP3 transcript and protein levels in cisplatin-resistant OC cells, revealing significantly higher MMP3 levels in cisplatin-resistant cells than in cisplatin-sensitive cells. siRNA-mediated MMP3 knockdown in cisplatin-resistant OC cells significantly reduced viability, proliferation, and invasion, and these effects were further enhanced when combined with cisplatin treatment, indicating a possible synergistic impact on reducing cancer cell aggressiveness; however, chemical MMP3 inhibition did not replicate these effects. RNA sequencing of MMP3-siRNA-treated cisplatin-resistant HGSOC cells revealed 415 differentially expressed genes (DEGs) compared to the negative control, with an additional 440 DEGs identified in MMP3-siRNA HGSOC cells treated in combination with cisplatin. These DEGs were enriched in pathways related to cell cycle regulation, apoptosis, metabolism, stress response, and extracellular matrix organization. Co-immunoprecipitation-coupled mass spectroscopy (IP-MS) identified MMP3-interacting proteins that may contribute to cell survival and chemoresistance in cisplatin-resistant OC. While MMP3-siRNA monotherapy did not reduce tumor growth in vivo, its combination with cisplatin significantly inhibited tumor growth in a cisplatin-resistant HGSOC xenograft model. These findings underscore the multifaceted role of MMP3 in cisplatin resistance, suggesting its involvement in critical cellular processes driving chemoresistance and highlighting the challenges associated with direct MMP3 targeting in therapeutic strategies. Full article

Boron-modified ceramic materials derived from polymers (PDC) are the subject of this research. The primary objective is to compare the structure and microstructure of SiBOC materials obtained in varying pyrolysis conditions in comparison to base SiOC materials. The preparation involved a number of stages, staring with the hydrolytic polycondensation method, followed by the initial thermal treatment and the final stage—pyrolysis process in argon or argon/hydrogen atmospheres at different temperatures. Bulk SiOC and SiBOC glasses were thoroughly analyzed. Microstructure studies included Scanning Electron Microscopy and Mercury Intrusion Porosimetry. Moreover, to confirm the structure, the research consisted of Fourier-Transform Infrared spectroscopy, Raman spectroscopy, and X-ray diffraction. The conducted research confirmed boron incorporation into the material structure in all samples. A free carbon phase has also been observed in SiBOC glasses, which has been confirmed in Raman spectroscopy measurements. This research indicates that in particular conditions, it is possible to obtain amorphous materials with nanocrystalline inclusions. This paper proves that the introduction of boron increases the porosity of materials and enhances their thermal stability. Full article

This study employs ab initio metadynamics to simulate the carbonization of Si(001) surfaces with chemical vapor deposition at a temperature of 1423 K. We reveal the complete reaction mechanism, including the beginning of silicon carbide crystal formation. The existence of surficial native oxide is incorporated into the theoretical model. The mechanism determination includes clarification of all intermediate products and transition states. The free-energy surface of the reaction chain has been found. Carbonization initiates with alkylated surface products and continues with consecutive dehydrogenation steps. Carbon is integrated in the volume, near the crystal surface, only if no covalent interactions with hydrogen atoms remain. The native oxide was not found to prohibit the process of carbonization. The oxygen atoms have certain surface mobility at high temperatures. It was revealed that hypervalency of carbon atoms is possible in transition state structures. The theoretical activation free energy of the rate-determining step was found to be only 166 kJ/mol. This work sheds light on the advantage of the practical use of Si(001) substrates for the synthesis of silicon carbide and Si-O-C glasses using direct carbonization via chemical vapor deposition. We also aim to enable more methodical designs of future synthetic routes and better-informed decisions for experimental investigations. Full article

A significant challenge during the polymer-to-ceramic pyrolysis conversion is to understand the polymer-to-ceramic atomic evolution and correlate the composition changes with the precursor molecular structures, pyrolysis conditions, and resulting ceramic characteristics. In this study, a Reactive Force Field (ReaxFF) simulation approach has been used to simulate silicon oxycarbide (SiOC) ceramic formation from four different polysiloxane precursors. For the first time, we show atomically that pyrolysis time and temperature proportionally impact the new Si-O rich and C rich cluster sizes as well as the composition separation of Si-O from C. Polymer side groups have a more complex effect on the Si-O and C cluster separation and growth, with ethyl group leading to the most Si-O cluster separation and phenyl group leading to the most C cluster separation. We also demonstrate never-before correlations of gas release with polymer molecular structures and functional groups. CH₄, C₂H₆, C₂H₄, and H₂ are preferentially released from the pyrolyzing systems. The sequence is determined by the polymer molecular structures. This work is the first to atomically illustrate the innate correlations between the polymer precursors and pyrolyzed ceramics. Full article

Polymer-derived SiOC ceramics (PDC_s-SiOC) possess advantages such as high temperature resistance, oxidation resistance, corrosion resistance, and customizable mechanical and dielectric properties. These attributes make them a promising material for high-temperature structural and functional applications. Based on polymer-derived ceramic conversion technology, this study synthesized a photosensitive resin with high ceramic yield and low shrinkage from commercial MK resin, 3-(trimethoxysilyl) propyl methacrylate, and trimethylolpropane triacrylate monomer. Using digital light processing additive manufacturing technology, 3D diamond-structured SiOC ceramic and 3D octahedron-structured SiOC ceramic with high precision were fabricated. The pyrolysis of both structures at different temperatures (1000 °C to 1400 °C) yielded SiOC ceramics, which exhibited uniform shrinkage in all directions, with a linear shrinkage rate ranging from 31% to 36%. The microstructure was characterized by FTIR, XRD, and SEM, respectively. Additionally, the compressive strength and elastic modulus of the three-dimensional SiOC ceramics were studied. The SiOC ceramic diamond lattice structure, fabricated through pyrolysis at 1200 °C, demonstrated good mechanical properties with a geometric density of 0.76 g/cm³. Its compressive strength and elastic modulus were measured at 7.66 MPa and 1.47 GPa, respectively. This study offers valuable insights into the rapid and customized manufacturing of lightweight ceramic structures. Full article

Background/Objectives: Ferroptosis, a type of programmed cell death, is mainly associated with disruptions in iron metabolism, imbalances in the amino acid antioxidant system, and the build-up of lipid peroxides. Triple-negative breast cancer (TNBC) has a dismal prognosis. Since activating ferroptosis can suppress breast cancer cell proliferation, it holds promise as a novel therapeutic target for breast cancer patients. Thus, the objective of this study was to clarify the mechanism of ferroptosis in TNBC, aiming to find new treatment strategies for TNBC patients. Methods: We screened out the differential genes related to ferroptosis in TNBC after GluOC treatment based on the whole-genome sequencing results. At the cellular level, we conducted explorations using techniques such as quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, fluorescence staining, and siRNA transfection. Moreover, we further verified the role of GluOC in inhibiting ferroptosis in TNBC through in vivo experiments using nude mice. Results: The results showed that GluOC enhanced glutathione expression levels by inducing SLC7A11 accumulation via the specific signaling pathway. Additionally, GluOC increased ATP production and tricarboxylic acid flux resistance to ferroptosis through SLC38A1. Overall, GluOC coordinately regulated SLC7A11 and SLC38A1 to inhibit ferroptosis in TNBC. Conclusions: This study elucidated the mechanism of GluOC in inhibiting ferroptosis in TNBC. The findings not only provided new insights into ferroptosis but also potentially offered new concepts for the development of future anticancer therapies, which may contribute to improving the treatment of TNBC patients. Full article

Photonic integrated circuits (PICs) are crucial for advanced applications in telecommunications, quantum computing, and biomedical fields. Silicon nitride (SiN)-based platforms are promising for PICs due to their transparency, low optical loss, and thermal stability. However, achieving efficient thermo-optic (TO) modulation on SiN remains challenging due to limited reconfigurability and high power requirements. This study aims to optimize TO phase shifters on SiN platforms to enhance power efficiency, reduce device footprint, and minimize insertion losses. We introduce a CMOS-compatible plasmo-photonic TO phase shifter using a SiOC material layer with a high TO coefficient combined with aluminum heaters on a SiN platform. We evaluate four interferometer architectures—symmetric and asymmetric Mach–Zehnder Interferometers (MZIs), an MZI with a ring resonator, and a single-arm design—through opto-thermal simulations to refine performance across power, losses, footprint, and switching speed metrics. The asymmetric MZI with ring resonator (A-MZI-RR) architecture demonstrated superior performance, with minimal power consumption (1.6 mW), low insertion loss (2.8 dB), and reduced length (14.4 μm), showing a favorable figure of merit compared to existing solutions. The optimized SiN-based TO switches show enhanced efficiency and compactness, supporting their potential for scalable, energy-efficient PICs suited to high-performance photonic applications. Full article

The betacoronavirus genus contains five of the seven human coronaviruses, making it a particularly critical area of research to prepare for future viral emergence. We utilized three human betacoronaviruses, one from each subgenus—HCoV-OC43 (embecovirus), SARS-CoV-2 (sarbecovirus), and MERS-CoV (merbecovirus)—, to study betacoronavirus interactions with the PKR-like ER kinase (PERK) pathway of the integrated stress response (ISR)/unfolded protein response (UPR). The PERK pathway becomes activated by an abundance of unfolded proteins within the endoplasmic reticulum (ER), leading to phosphorylation of eIF2α and translational attenuation. We demonstrate that MERS-CoV, HCoV-OC43, and SARS-CoV-2 all activate PERK and induce responses downstream of p-eIF2α, while only SARS-CoV-2 induces detectable p-eIF2α during infection. Using a small molecule inhibitor of eIF2α dephosphorylation, we provide evidence that MERS-CoV and HCoV-OC43 maximize viral replication through p-eIF2α dephosphorylation. Interestingly, genetic ablation of growth arrest and DNA damage-inducible protein (GADD34) expression, an inducible protein phosphatase 1 (PP1)-interacting partner targeting eIF2α for dephosphorylation, did not significantly alter HCoV-OC43 or SARS-CoV-2 replication, while siRNA knockdown of the constitutive PP1 partner, constitutive repressor of eIF2α phosphorylation (CReP), dramatically reduced HCoV-OC43 replication. Combining GADD34 knockout with CReP knockdown had the maximum impact on HCoV-OC43 replication, while SARS-CoV-2 replication was unaffected. Overall, we conclude that eIF2α dephosphorylation is critical for efficient protein production and replication during MERS-CoV and HCoV-OC43 infection. SARS-CoV-2, however, appears to be insensitive to p-eIF2α and, during infection, may even downregulate dephosphorylation to limit host translation. Full article

Ovarian cancer (OC) is the second most common female reproductive cancer and the most lethal gynecological malignancy worldwide. Most human OCs are characterized by high rates of drug resistance and metastasis, leading to poor prognosis. Improving the outcomes of patients with relapsed and treatment-resistant OC remains a challenge. This study aimed to investigate the role of epidermal growth factor-like domain 8 (EGFL8) in human OC by examining the effects of siRNA-mediated EGFL8 knockdown on cancer progression. EGFL8 knockdown in human OC cells promoted aggressive traits associated with cancer progression, including enhanced proliferation, colony formation, migration, invasion, chemoresistance, and reduced apoptosis. Additionally, knockdown upregulated the expression of epithelial–mesenchymal transition (EMT) markers (Snail, Twist1, Zeb1, Zeb2, and vimentin) and cancer stem cell biomarkers (Oct4, Sox2, Nanog, KLF4, and ALDH1A1), and increased the expression of matrix metallopeptidases (MMP-2 and MMP-9), drug resistance genes (MDR1 and MRP1), and Notch1. Low EGFL8 expression also correlated with poor prognosis in human OC. Overall, this study provides crucial evidence that EGFL8 inhibits the proliferation and cancer aggressiveness of human OC cells by suppressing ERK/MAPK signaling. Therefore, EGFL8 may serve as a valuable prognostic biomarker and a potential target for developing novel human OC therapies. Full article