Search Results (294)

Background/Objectives: Variants of MYPN, encoding a sarcomeric protein myopalladin, are associated with different types of cardiomyopathies and myopathies. However, the molecular mechanisms of MYPN-associated pathologies are still poorly understood. Methods: In this study, we generated induced pluripotent stem cells (iPSCs) from a hypertrophic cardiomyopathy patient carrying a novel p.N989I (c.2966A>T) variant of MYPN and used iPSC-derived cardiomyocytes to examine the impact of the variant on biophysical characteristics and transcriptomic profile. Results: No significant changes in parameters of calcium transients, sodium current and action potential were found in iPSC-derived cardiomyocytes with the p.N989I (c.2966A>T) variant of MYPN compared to non-isogenic cells from an unrelated healthy donor. At the transcriptomic level, MYPN-N989I cardiomyocytes demonstrated an upregulation of genes linked to cell cycle, mitotic spindle, microtubule cytoskeleton organization, and myogenic program genes. Downregulation of sarcomeric, Z-disc- and cell junction-associated genes, as well as genes involved in ATP synthesis, oxidative phosphorylation, and the SRF-signaling pathway, was also revealed. Conclusions: Our data suggest that the p.N989I (c.2966A>T) variant of MYPN plays a dual role in hypertrophic cardiomyopathy pathogenesis, disrupting not only sarcomeric and cytoskeletal organization but also the regulation of the muscle gene program. Full article

The field of perovskites continues to advance each day, with new materials being discovered in order to eliminate the toxic and less efficient ones. Some of the challenges currently facing the perovskite industry include coming up with materials with higher electrical conductivity and lower thermal conductivity, as well as p-type semiconductors. In an attempt to address these challenges, this study modeled two novel perovskites from potassium hexachloroosmate (VI) (K₂OsCl₆) by replacing some of the chlorine atoms with those of silver, then characterized their structural, electronic (using both conventional and hybrid functionals), and thermoelectric properties using Quantum Espresso and BoltzTrap2 codes. The calculations were performed within the framework of density functional theory. The results showed that the novel materials exhibited higher density, lower thermal conductivity, lower band gaps, and positive Hall coefficient, unlike the K₂OsCl₆ sample. These materials can thus be used in areas such as in p–n junctions, thermoelectric devices, and optoelectronic devices. However, since this study was purely computational, the properties need to be verified through an experimental study. Full article

This paper presents a miniaturized tunable bandpass filter chip fabricated using a gallium arsenide (GaAs) technology. In the layout design, a quasi-lumped element is utilized to replace conventional spiral inductors, complemented by on-chip PN-junction varactor diodes and Metal-Insulator-Metal (MIM) capacitors. The integration of a source-load coupling structure and grounded series LC resonators introduces three transmission zeros (TZs), enhancing the frequency selectivity. By independently tuning the coupling capacitance and the grounded series LC resonant structures, the operating frequency of the filter achieves continuous tunability. An equivalent circuit model is established to analyze the filter’s performance. For experimental verification, the proposed filter was fabricated and measured, occupying a compact die area of 1.35 × 1.365 mm². The measured results demonstrate a center frequency tuning range from 5.4 to 6.2 GHz, showing good agreement with simulation and thus validating the proposed miniaturized continuously tunable filter. Full article

This study investigates the electrical performance of two 4H-SiC p⁺-i-n⁻ diodes, based on lightly doped epitaxial layers, representative of high-voltage and neutron-detector structures. Each design was implemented in multiple nominally identical devices and characterized over the temperature range 298–623 K, with particular attention to the influence of p⁺ layer fabrication, n-type epitaxial layer thickness, and doping concentration. One diode features an ion-implanted p⁺ layer on a 250 µm thick n-type epitaxial layer, while the other employs an epitaxially grown p⁺ layer on a 100 µm thick n-type epitaxial layer. A comparison of reverse-bias Current–Voltage (I–V) and Capacitance–Voltage (C–V) characteristics indicates that, although both designs exhibit high-quality epitaxial 4H-SiC material, devices with an implanted p⁺ anode tend to show a more pronounced temperature-dependence and degradation of selected electrical parameters in reverse bias than those with an epitaxial p⁺ anode, while forward I–V in the range 298–623 K remains broadly similar for both designs. These observations suggest that anode fabrication and epitaxial design may jointly influence thermal stability, recombination mechanisms, and overall electrical performance, offering guidance for the optimization of 4H-SiC-based power and neutron-detector devices for high-temperature and harsh environments. Full article

The solar-driven direct conversion of methanol to ethylene glycol, formaldehyde and simultaneous H₂ generation is an appealing strategy for converting sunlight to chemical energy. However, the low efficiency and stability of the photocatalyst remain critical bottlenecks hindering the practical implementation of this reaction. Herein, we synthesized the Cu₃P quantum dots/Cu-doped ZnIn₂S₄ p-n junction for efficient methanol oxidation and synchronous H₂ generation. The highly dispersed Cu₃P quantum dots promote electron–hole separation and furnish abundant catalytic sites. Moreover, the constructed p-n junction with a tight interface boosts the electron transfer, avoiding the serious photocorrosion of ZnIn₂S₄. Benefiting from these synergistic effects, the 2Cu₃P/Cu_0.5ZIS composite exhibits the highest photocatalytic conversion efficiency of methanol, yielding H₂, formaldehyde, and ethylene glycol with 10.34 mmol·g⁻¹·h⁻¹, 10.35 mmol·g⁻¹·h⁻¹ and 8.84 mmol·g⁻¹·h⁻¹ yields, which are 3.01, 3.05 and 3.10 times those of pure ZnIn₂S₄, respectively. A series of characterizations including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and UV-Vis diffuse reflectance spectroscopy are employed to analyze the structure, composition, and photoelectrochemical properties of the materials. This work demonstrates a novel catalyst design paradigm for the high-efficiency solar light-driven photocatalytic activation of methanol enabling the co-production of value-added C1/C2 oxygenates and clean H₂ fuel simultaneously. Full article

Although tungsten oxide (WO₃)-based NO₂ sensors have been extensively studied, achieving high sensitivity at low operating temperatures remains a significant challenge. To address this limitation, we designed a WO₃/SiNWs heterojunction-based sensor, fabricated through metal-assisted chemical etching followed by hydrothermal synthesis. Structural and morphological analyses confirm the uniform integration of WO₃ nanorods onto SiNWs and the establishment of an effective p–n junction. The optimized sensor exhibits a response of 238 toward 1 ppm NO₂ at 127 °C with a response/recovery times of 14.8 s/99.2 s. The improved performance stems from the heterojunction-driven enhancement of charge carrier separation and surface adsorption sites, offering a viable route for developing low-power, high-performance gas sensors. Full article

Dye-sensitized solar cells (DSSCs) have attracted significant attention as next-generation photovoltaic devices due to their low cost, simple fabrication process, use of earth-abundant materials, and potential for colour tunability and transparency. p–n tandem DSSCs have garnered particular interest owing to their higher open-circuit voltage compared to single-junction DSSCs. However, the performance of such tandem devices remains limited by relatively low open-circuit voltage and short-circuit current density, primarily due to the scarcity of suitable p-type sensitizers. To address this challenge, we report a novel p–n tandem solar cell integrating a dye-sensitized TiO₂ photoanode with a perovskite-sensitized NiO photocathode, achieving a record power conversion efficiency of 4.02%. By optimizing the thickness of the TiO₂ layer, a maximum open-circuit voltage of 1060 mV and a peak short-circuit current density of 6.11 mA cm⁻² were simultaneously attained. Full article

Ammonia, as an essential chemical, plays an indispensable role in both industry and agriculture. However, the traditional Haber–Bosch technique for ammonia synthesis suffers from high energy consumption and significant CO₂ emissions. Therefore, developing an energy-efficient and eco-friendly method for ammonia production is imperative. Photoelectrochemical (PEC) nitrate reduction to ammonia has emerged as a promising green alternative, which utilizes renewable solar energy to convert nitrate into valuable ammonia, thereby contributing to nitrogen recycling and wastewater remediation. This review systematically summarizes recent advances in PEC nitrate reduction to ammonia, focusing on the rational design of efficient photocathodes with the development of semiconductor materials, cocatalysts, p–n junction and heterostructure strategies. Furthermore, the integration of photocathodes with photoanodes enables the assembly of bias-free PEC systems capable of simultaneously producing ammonia and value-added chemicals, demonstrating the potential for scalable solar-driven ammonia synthesis. The mechanistic studies and future research directions are also discussed. The review aims to offer valuable insights and promote the further development of PEC nitrate reduction to ammonia. Full article

This work reports the design and realization of a silicon-based micro photovoltaic generator (MPG) fabricated using a standard 0.18 μm complementary metal oxide semiconductor (CMOS) technology. The device harvests optical energy and converts it into electrical power through the photovoltaic effect, leveraging a network of engineered p–n junctions formed within the semiconductor. A grid-structured architecture is adopted, in which patterned p-type regions are embedded inside an n-well platform. This configuration expands the effective junction area, increases carrier-collection paths, and strengthens the internal electric field, thereby enhancing photocurrent generation. To further improve optical coupling, a specialized post-CMOS treatment is introduced. A wet etching is used to selectively remove the silicon dioxide layer that normally covers the junction regions in CMOS processes. Eliminating this dielectric layer enables direct photon penetration into the depletion region minimizes reflection-related losses, resulting in a significant improvement in device performance. Under an illumination intensity of 1000 W/m², the fabricated microgenerator delivers an open-circuit voltage of 0.49 V, a short-circuit current of 239 µA, and a maximum output power of 90 µW. The device exhibits an overall energy conversion efficiency of 12.9%, confirming the effectiveness of the grid-like junction design and the post-processing oxide removal. Full article

Quantum dots (QDs) composed of the narrow-bandgap semiconductor PbTe were incorporated into the depletion region of p–n junctions based on wide-bandgap II–VI semiconductors (p-ZnTe/n-CdTe). The heterostructures were grown by molecular beam epitaxy (MBE) on semi-insulating GaAs (100) substrates. The depletion region was engineered by depositing 20 alternating thin layers of CdTe and PbTe, then thermal annealing under ultrahigh vacuum. As revealed by cross-sectional scanning electron microscopy (SEM), the initially continuous PbTe layers transformed into arrays of zero-dimensional nanostructures, namely PbTe QDs. The formation of PbTe QDs in a CdTe matrix arises from the structural mismatch between the zinc blende and rock-salt crystal structures of the two materials. Electron beam-induced current (EBIC) scans confirmed that the QDs are localized within the depleted charge region between the p-ZnTe and n-CdTe layers. The resulting wide-gap diodes containing narrow-band QDs show pronounced sensitivity to infrared radiation in the spectral range of 1–4.5 μm, with a peak responsivity of approximately 8 V/W at a wavelength of ~2.0 μm and a temperature of 200 K. A red-shift in the cutoff wavelength when temperature decreases indicates that the infrared (IR) response is governed by band-to-band optical transitions in the PbTe QDs. In addition, the devices show sensitivity to visible radiation, with a maximum responsivity of 20 V/W at 0.69 μm. These results demonstrate that wide-bandgap p–n junctions incorporating narrow-bandgap QDs can function as dual-wavelength (visible and infrared) photodetectors, with potential applications in two-color detection and infrared solar cells. Full article

Multiband solar cells offer a promising route to surpass the Shockley-Queisser limit by harnessing sub-bandgap photons through three active energy band transitions. However, realizing their full potential requires overcoming key challenges in material design and device architecture. Here, we propose a novel multiband stacked anti-parallel junction solar cell structure based on highly mismatched alloys (HMAs), in particular dilute GaAsN with ~1–4% N. An anti-parallel junction consists of two semiconductor junctions connected with opposite polarity, enabling bidirectional current control. The structures of the proposed devices are based on dilute GaAsN with anti-parallel junctions, which allow the elimination of tunneling junctions—a critical yet complex component in conventional multijunction solar cells. Semiconductors with three active energy bands have demonstrated the unique properties of carrier transport through the stacked anti-parallel junctions via tunnel currents. By leveraging highly mismatched alloys with tailored electronic properties, our design enables bidirectional carrier generation through forward- and reverse-biased diodes in series, significantly enhancing photocurrent extraction. Through detailed SCAPS-1D simulations, we demonstrate that strategically placed blocking layers prevent carrier recombination at contacts while preserving the three regions of photon absorption in a single multiband semiconductor p/n junction. Remarkably, our optimized five-stacked anti-parallel junctions structure achieves a maximum theoretical conversion efficiency of 70% under 100 suns illumination, rivaling the performance of state-of-the-art six-junctions III-V solar cells—but without the fabrication complexity of multijunction solar cells associated with tunnel junctions. This work establishes that highly mismatched alloys are a viable platform for high efficiency solar cells with simplified structures. Full article

The CoolMOS™ (Infineon Technologies AG, Munich, Germany) has been considered a device that alleviates high-voltage limitations of unipolar power devices, but although the theoretical considerations seem to confirm such a possibility, this expectation has not been fulfilled until now. This paper identifies limitations of the CoolMOS™ concept. The analysis was carried out in two steps. The first step aimed at the theory of high-voltage superjunction and its implementation into a power VDMOS transistor, which resulted in the modified construction called CoolMOS™. The investigations have shown that the superjunction effect is not an inherent feature of high voltage junctions formed as a characteristic meander-like p-n junction. Such a junction starts to work in SuperJunction Mode (SJM) just when the electric field strength reaches the magnitude of the threshold electric field E_th. Also, other theoretical constraints concerning the SJ diode and CoolMOS™ design have been presented. The second step aimed at the physical and technological limitations that have been identified, taking advantage of numerical investigations for CoolMOS™ structures developed on the basis of a typical VDMOS one. Full article

Background/Objectives: Acephalic spermatozoa syndrome (ASS) is a rare subtype of male infertility characterized by headless sperm due to defective head–tail coupling. Genetic factors are recognized as the primary etiology of ASS; however, known pathogenic mutations only explain a subset of ASS cases. Further investigations are required to elucidate the underlying genetic pathogenesis of ASS and the implications of such genetic defects for assisted reproductive technology (ART) outcomes. This study aimed to identify a novel PMFBP1 mutation in an ASS patient; investigate the effects of the identified mutation on sperm ultrastructure and PMFBP1 protein expression/stability, and assess ART outcomes using the patient’s sperm. Methods: One 34-year-old infertile male with ASS was enrolled. Genetic screening was performed via whole-exome sequencing (WES), followed by Sanger sequencing for mutation validation. Sperm morphological characteristics were evaluated using Diff-Quik staining (for general morphology), transmission electron microscopy (TEM, for ultrastructural analysis), and peanut agglutinin (PNA) staining. Protein expression and stability were analyzed by Western blot and cycloheximide (CHX)/MG132 assays. ART outcomes were compared between the in vitro fertilization (IVF) cycles using the patient’s sperm and those using donor sperm. Results: In IVF cycles, donor sperm achieved normal fertilization (characterized by two pronuclei [2PN] formation), whereas the patient’s sperm failed to form 2PN and leading to embryo fragmentation. Genetic sequencing identified a novel nonsense mutation in PMFBP1 (c.2641C>T), which introduced a premature stop codon and resulted in a premature protein product (p.Arg881Ter). Morphologically, this mutation led to complete sperm head–tail detachment, and abnormalities in acrosome structure and sperm head–neck junction. The absence of PMFBP1 protein in the patient’s spermatozoa was observed. The in vitro assays showed the c.2641C>T mutation induced expression of the truncated PMFBP1 protein and significantly altered PMFBP1 protein stability. Conclusions: The PMFBP1 c.2641C>T mutation impairs sperm head–tail adhesion, thereby contributing to the pathogenesis of ASS. This study expands the clinical mutational spectrum of PMFBP1-associated male infertility and provides valuable insights for the genetic diagnosis of ASS patients. Additionally, these findings may lay a foundation for the choice of therapeutic strategies targeting PMFBP1-related ASS. Full article

Silicon photonics offers a powerful route to leverage existing microelectronics infrastructure to enhance performance and enable new applications in data processing and sensing. Among the available material platforms, silicon nitride (Si₃N₄) provides significant advantages due to its wide optical transmission window. A key challenge, however, remains the monolithic integration of passive nitride-based photonic components with active electronic devices directly on silicon wafers. In this work, we propose and demonstrate a tapered bottom-cladding design that enables efficient coupling of visible light from Si₃N₄/SiO₂ core–cladding waveguides into planar p–n junction photodiodes fabricated on the silicon surface. Si₃N₄/SiO₂ waveguides were fabricated using fully CMOS-compatible processes and materials. Controlled reactive ion etching (RIE) of SiO₂ allowed the formation of vertically tapered claddings, and finite-difference time-domain (FDTD) simulations were carried out to analyze coupling efficiency across wavelengths from 509 nm to 740 nm. Simulations showed transmission efficiencies above 90% for taper angles below 30°, with near-total coupling at 10°. Experimental fabrication achieved angles as low as 8°. Responsivity simulations yielded values up to 311 mA W⁻¹ for photodiodes without internal gain. These results demonstrate the feasibility of fabricating monolithic Si-based waveguide–photodetector systems using simple, CMOS-compatible methods, opening a scalable path for integrated photonic–electronic devices operating in the visible range. Full article

Background/Objectives: To identify independent predictors of free peritoneal cancer cells (FPCC), and to investigate survival outcomes relative to peritoneal cytology status among patients who underwent intended curative gastrectomy for adenocarcinoma of the stomach or esophagogastric junction. Methods: Medical records of patients who underwent radical surgery between January 2005 and December 2020 were retrospectively reviewed. Clinical data and cytology results were evaluated. Multivariate Cox regression analysis was used to identify independent predictors of FPCC. Kaplan–Meier survival analysis was used to estimate disease recurrence and survival outcomes. Results: Out of the 349 enrolled patients, 188 (53.8%) had negative cytology, 32 (9.2%) were positive, and 129 (36.9%) showed atypical cells in peritoneal cytology. Poor differentiation (adjusted odds ratio [aOR]: 2.63, 95% confidence interval [95%CI]: 1.04–6.82; p = 0.015), pT4 (aOR: 4.62, 95%CI: 1.28–14.34; p = 0.018), pN3 (aOR: 4.13, 95%CI: 1.14–15.03; p = 0.031), and metastatic lymph node ratio >0.40 (aOR: 6.49, 95%CI: 1.44–29.14; p = 0.015) were independent predictors of FPCC. Median overall survival was 34.1 months in the negative group, 13.1 months in the positive group, and 28.7 months in the atypical cell group (p < 0.001). Median time to disease recurrence was 20.5, 4.9, and 11.3 months, respectively (p < 0.001). Survival and recurrence outcomes in the atypical cell group were comparable to those with negative cytology. Conclusions: Poorly differentiated histology, pT4, pN3, and metastatic lymph node ratio >0.40 are independent predictors of FPCC, which is significantly associated with poor survival and disease recurrence outcomes. These findings suggest that high-risk patients may benefit from routine peritoneal cytologic screening during surgery to improve risk stratification and guide postoperative treatment planning. Full article