Search Results (820)

Biological manipulation via physical stimuli such as light and magnetism has become a central goal in modern biotechnology. Among these modalities, magnetic fields offer unique advantages, including deep tissue penetration and untethered interventions in living systems. An ideal platform for such a magnetogenetic toolkit would be a genetically encodable protein with tunable magnetic features under physiological conditions. However, the development of such tools has been hindered by the lack of robust and stable protein scaffolds with strong intrinsic magnetic properties. Inspired by animal magnetoreception in nature, here, we rationally designed and systematically screened single-chain variants of the magnetoreceptor MagR. Through nine iterative rounds of design and experimental validation, we generated 25 constructs and ultimately identified a stable single-chain-dimer-based-tetramer, SDT-MagR, as the optimal magnetic molecular platform. This engineered protein exhibits exceptional structural stability and state-dependent magnetic behavior, showing ferrimagnetic-like characteristics in the solid state and paramagnetic behavior in solution. With enhanced magnetic susceptibility, purified SDT-MagR can be directly attracted by a magnet in vitro, establishing it as a promising new platform for future biomagnetic manipulation and magnetogenetics applications. Full article

This study proposes a 300 W class Gallium Nitride (GaN) Solid-State Power Amplifier (SSPA)-based microwave plasma generator system for implementing next-generation light sources with high brightness and color rendering at 2.45 GHz. To overcome the lifetime limitations and control constraints of conventional magnetron systems, the proposed system introduces custom packaging technology utilizing GaN-on-SiC Bare-dies fabricated via the Win-semiconductor’s NP25 process. This approach minimizes parasitic components and significantly reduces thermal resistance compared to standard packages, ensuring reliability during high-power operation. A stable RF output of 300 W was achieved through two-stage power combining. For the plasma source, an Ar-InBr-Hg gas mixture was employed to optimize optical characteristics. This gas mixture is commonly used in electrodeless plasma lamps due to its high luminous efficacy and stable discharge characteristics. To analyze the rapid impedance discontinuity during gas ignition, numerical analysis based on the Drude model was performed, theoretically identifying the complex permittivity transition of the medium and the resulting resonant frequency up-shift mechanism. To mitigate system instability during this transition, an adaptive frequency tracking and feedback control loop based on real-time VSWR monitoring was implemented. Experimental results demonstrate precise tracking within a 100 MHz frequency variable range, achieving a system efficiency of over 53% and maintaining a VSWR below 1.15:1. These results validate the practical feasibility of GaN SSPA technology in electrodeless lighting and industrial plasma applications utilizing high-power RF energy. Full article

Quantum random number generation (QRNG) provides fundamentally unpredictable randomness derived from intrinsic quantum processes. In this work we demonstrate two solid-state, room-temperature QRNG implementations based on nitrogen-vacancy (NV) centers in diamond, i.e., ensemble fluorescence from nanodiamonds and single-photon emission from single NV centers located at the tips of fabricated diamond nanopillars for enhanced light collection efficiency, spatial isolation and minimized crosstalk. We compare entropy rates (above 0.98 bits), statistical performance, and robustness of both approaches in our experimental setup, the results contribute to establishing diamond-based QRNG as a scalable solution for quantum-secure randomness generation. Full article

Inspired by the growing demand for small and effective optoelectronic devices, this paper presents a simulation-based analysis of InGaN/GaN quantum dot light-emitting diode, focusing on the effects of systematic variation in both anode and cathode contact regions, as well as overall device size. Two-dimensional simulations using APSYS software were used to examine the impact of scaling the device dimensions as well as the individual contact dimensions on significant performance parameters like internal quantum efficiency (IQE), optical output power, and current-voltage (IV) response. We simulated five LED device sizes that is 50 × 50 µm², 100 × 100 µm², 200 × 200 µm², 300 × 300 µm², and 400 × 400 µm². As device size grows, so does the total current at each voltage. The highest current measurement is achieved by the device with dimensions 400 × 400 µm² while the lowest is observed on the device with dimensions 50 × 50 µm². In addition to changing the device dimensions, we ran extensive simulations on the sizes of p-type and n-type contacts. Notable changes were seen in the efficiency, optical power, and emission profile of the p-contact. The behavior of p-side contacts from 0 to 50 µm was the same, while contacts between 60 and 100 µm showed significant differences. The significant performance parameters were unaffected by changes to n-contact dimensions. The results of this study illustrate how the configuration of contacts and dimensions greatly influences the electrical and optical performance of quantum dot light-emitting diode. The results are believed to be helpful to researchers working on the design of next-generation compact and efficient solid-state lighting devices. Full article

α-Fe_2−4xZ_3xO₃ (Z = Ce, Ru) nanoparticles were synthesized via a conventional solid-state reaction route. X-Ray diffraction analysis confirmed that all compositions crystallize in the single-phase hexagonal hematite (α-Fe₂O₃) structure, with no detectable secondary phases. Cerium substitution resulted in a pronounced reduction in crystallite size accompanied by a progressive narrowing of the optical band gap, which decreased to approximately 1.73 eV at higher Ce contents. The optical properties were further investigated through absorption coefficient, optical transmittance, and complex refractive index analyses, revealing that cerium-doped hematite exhibits enhanced light-harvesting capability, highlighting its strong potential for optoelectronic and solar-energy conversion applications. Magnetic hysteresis measurements on α-Fe_2−4xRu_3xO₃ samples showed a systematic increase in both coercive field (H_c) and remanent magnetization (M_r) with increasing Ru concentration. This magnetic hardening behavior is attributed to strengthened magnetocrystalline and shape anisotropy induced by Ru incorporation into the hematite lattice. Mössbauer spectroscopy confirmed the presence of Fe³⁺ and Ru⁴⁺ species, providing valuable insight into the oxidation states and local magnetic environments within the corundum-type structure. Full article

Background/Objectives: The formulation development of Isotretinoin (ISN) is limited by its solubility and stability issues. This study aimed to characterise the BCS class II drug ISN, particularly the possible different solid state and formulate amorphous solid dispersion aiming for a supersaturation state. Methods: ISN’s physical states are investigated in its raw form, quench-cooled form, physical mixture with the polymer and corresponding solid dispersion form. Quench-cooled ISN was prepared in situ using DSC. Carrier stabilisation of ISN was attempted using the solid dispersion technique. Hereby, the solid dispersion of drug-polymer PVPVA at a ratio of 1:3 was prepared using the solvent evaporation method. Solid dispersion, physical mixture and raw ISN were characterised for the saturated solubility. Physical characterisation of the samples was performed using DSC, ATR-FTIR and a light microscope. Results: Two polymorphs of ISN (forms I and II) were found in the raw ISN, with form II being thermodynamically more stable. ISN possesses strong crystallinity and resistance to amorphisation under the applied quench-cooling condition without the presence of a carrier system. The conjugated polyene structure in ISN contributes to the polymorphic transformation and isomerisation. The incorporation of PVPVA in the solid dispersion system successfully improved the water solubility (sixfold) of ISN despite a combination of crystalline and amorphous components being present in the system. Conclusions: ISN is a class II drug crystal molecule. Taking advantage of solubility and possibility in the polymorphic transformation of ISN in a binary system, we concluded that ISN could potentially be formulated into its corresponding crystalline solid dispersion form. Full article

Understanding the molecular mechanisms of carcinogenesis, including disruptions in the homologous recombination system, is fundamental to understanding malignant transformation. Dysfunction of homologous recombination genes, such as BRCA1 and BRCA2, contributes to genomic instability and the development of more aggressive tumor clones. The use of chemical carcinogens enables the modeling of tumor formation and the monitoring of changes in molecular genetic parameters. This approach is important for understanding how tumor cells adapt to genotoxic stress and for advancing the development of personalized cancer therapies. The objective of this study was to evaluate the expression of key homologous recombination system genes in a model of chemically induced carcinogenesis in mice. Materials and Methods: Male outbred ICR (CD-1) laboratory mice (n = 40) were used to study chemically induced carcinogenesis. The animals were divided into four groups: two control groups and two experimental groups, which received 3-methylcholanthrene (MC) or trichloroacetic acid (TCA). Tumor cells were identified by histological analysis of autopsy material using light microscopy after standard hematoxylin and eosin staining. RNA and DNA were extracted from cell suspensions using the RNeasy Plus Mini Kit and QIAamp DNA Mini Kit (Qiagen, Hilden, Germany), respectively. The expression levels of homologous recombination genes were assessed by RT-PCR and microarray analysis. Digital PCR was performed to assess chromosomal aberrations in the Brca1 gene. Results: Tumor formations were identified in laboratory animals two months after 3-methylcholanthrene. Histological analysis revealed morphological changes in a pleomorphic cell tumor, forming diverse, multidirectional fascicular and swirling structures, as well as large solid foci composed of markedly polymorphic spindle-shaped and epithelioid cells. Analysis of copy number aberrations in the examined samples showed that the frequency of Brca1 deletions was 60%, while 40% of animals had normal gene copy number. To further characterize the molecular changes, we assessed gene expression levels through expression microarray analysis. A total of 14 genes were hypoexpressed in the tumor compared to the normal tissue, with p < 0.05. A high level of differential expression was characteristic for Rad50, Rad51, Brca1, Brca2, and Pold4. Two genes, Rad52 and Bard1, exhibited increased expression levels. It was shown that as the tumor mass increased, so did the frequency of homologous recombination genes with hypoexpression. Conclusions: Our findings confirm that MC and TCA influence tumor formation and reveal that suppression of homologous recombination genes may contribute to this process. In addition, it has been established that as tumors progress, the expression of DNA repair genes declines and aberrant gene states accumulate. These data emphasize the importance of studying the state of DNA repair genes for the development of more effective strategies for cancer diagnosis and therapy. Full article

Solid-state lighting, especially light-emitting diodes (LEDs), is revolutionizing indoor lighting due to its energy efficiency, long lifespan, low heat output, and enhanced color rendering. LEDs can quickly adjust light intensity, enabling the development of visible light communication (VLC) technology. However, the modulation bandwidth of phosphor-converted white LEDs commonly used for illumination is limited, potentially affecting the speed of the VLC links. This paper presents a receiver-side equalization technique to overcome bandwidth limitations in VLC links due to LEDs. The proposed approach utilizes a novel transimpedance amplifier with an embedded T-network shunt-feedback equalizer (TIA-TE) to introduce adjustable high-frequency peaking in the TIA’s frequency response. By incorporating this peaking, the system’s bandwidth is extended without sacrificing important performance parameters like gain, noise, or power dissipation. The TIA-TE is followed by a main amplifier and a standalone continuous-time linear equalizer (CTLE) for further signal conditioning, while a 50 Ω buffer interfaces the receiver with measurement equipment. Post-layout simulations in a 0.35 µm CMOS process validate the approach. Using a 4 pF photodiode, the system bandwidth was initially limited by the LED’s 3 MHz modulation bandwidth. The proposed TIA-TE extends the bandwidth to 8.4 GHz without sacrificing the gain or power dissipation. The subsequent CTLE further extends the bandwidth to 14 MHz. The receiver front end achieves a mid-band transimpedance of 110 dBΩ and an input-referred noise current of 7.2 nA_rms, while dissipating 2.48 mW (excluding the 50 Ω buffer). Simulated 28 Mb/s NRZ eye diagrams demonstrate the feasibility of the proposed TIA-TE architecture for LED-limited VLC links. Full article

The photocatalytic activity as a function of effective irradiance, photocatalytic quantum yield and reactant coverage was thoroughly assessed for the proper photoreactor (PhR) selection. The emitted wavelength and effective irradiance of several PhRs, equipped with fluorescent and light-emitting diode (LED) lamps, were tested in the photodegradation of methylene blue (MB) in the solid phase using an AgTiO₂ photocatalyst. Among all tested PhRs, the one equipped with the low-pressure Hg lamp enhanced the photodegradation of MB, as the Hg lamp emitted UV-type radiation, which promotes the simultaneous photoactivation of the TiO₂ and the surface plasmon resonance phenomenon of the Ag nanoparticles. It was determined that high values of effective irradiance promoted photocatalytic activity because of the greater amount of photogenerated species [e⁻/h⁺]. Also, it was determined that the effective irradiance used in the photocatalytic process slows down the recombination rate of the [e⁻/h⁺] into photocatalytic material. A kinetic photocatalytic model (KPM) was proposed to describe photocatalytic reactions as a function of effective irradiance, photocatalytic quantum yield and reactant coverage, considering photocatalytic pseudo-steady state according to the reactant equilibrium coverage (Langmuir isotherm) and the transfer processes of the photoinduced charge carrier species. Full article

Since the first synthetic macrocyclic receptors were shown to bind ions selectively, supramolecular host–guest chemistry has enabled the translation of molecular recognition events into physical signals. Early coupling of such receptors to ion-sensitive field-effect transistors established a bridge between supramolecular chemistry and solid-state electronics. Today, this bridge is rebuilt in iontronics, where ions carry information through nanoconfined media and ionic transport becomes highly sensitive to electrostatic gradients, surface charge, and surface molecular interactions. As a result, ionic flux can serve as an efficient transduction mechanism that responds precisely, reversibly, and rapidly to changes in the chemical environment. Within this regime, host–guest chemistry offers a powerful means to exert direct control over ionic behavior, allowing molecular recognition to modulate conductance, rectification, and ion selectivity, thereby conferring practical function to nanofluidic systems. This review highlights systems in which host molecules act as chemical actuators that modulate nanochannel surface chemistry, thereby regulating ionic flux and enabling reversible, tunable, and stimulus-responsive behaviors. We survey architectures in which crown ethers, calixcrowns, pillararenes, and related hosts are integrated into solid-state nanochannels, emphasizing representative achievements such as biological-level Na⁺/K⁺ selectivity in crown ether-based systems and nanomolar-level detection of ions using calixcrowns- and pillararene-functionalized nanochannels. Finally, we discuss how temperature, pH, light, and redox state act as external stimuli that reversibly switch between conductive states, yielding ion-selective platforms for sensing and ion sieving. Full article

Laser slicing of 4H-SiC wafers offers high efficiency and minimal material loss. While nanosecond lasers are the preferred light source, simultaneously achieving high output power, excellent beam quality (M² < 1.3), and broad operational tunability remains an outstanding challenge. This study developed a highly efficient nanosecond laser source using hybrid fiber and solid-state multi-stage amplification architecture. With excellent beam quality (M² < 1.3), it achieves the highest output power, widest continuously tunable pulse width range, and broadest repetition rate range currently reported for 4H-SiC laser slicing. This advancement is poised to advance the continued development of 4H-SiC slicing technology. Full article

Bismuth-based semiconductors have emerged as a promising class of visible-light-responsive photo(electro)catalysts for environmental remediation owing to their tunable electronic structures, moderate band gaps, and relatively low toxicity. The stereochemically active Bi³⁺ 6s² lone pair and strong Bi–O orbital hybridization tailor valence-band states, enabling enhanced utilization of the solar spectrum and favorable charge-carrier dynamics. In addition, layered, perovskite-like, and aurivillius-type crystal frameworks generate internal electric fields that are advantageous for photoelectrochemical (PEC) operation. This review critically examines advances from 2015 to 2025 in the design, synthesis, modification, and environmental applications of bismuth-based photo(electro)catalysts, with particular emphasis on PEC systems for pollutant degradation. Major material families, including bismuth oxides, oxyhalides, oxychalcogenides, chalcogenides, perovskite-like oxides, and complex metal oxides, are discussed in relation to their structure–property–performance relationships. Key synthesis strategies, such as solid-state, sol–gel, hydro/solvothermal, microwave-assisted, spray pyrolysis, and electrodeposition methods, are compared with respect to morphology control, defect chemistry, and electrode integration. Performance-enhancing approaches, including elemental doping, oxygen-vacancy engineering, and the rational design of type-II, p–n, Z-scheme, and S-scheme heterojunctions, are critically assessed. Practical considerations related to stability, scalability, and techno-economic constraints are highlighted. Finally, current challenges and future directions toward durable and application-ready bismuth-based PEC technologies are outlined. Full article

Carbon dots have emerged as promising luminescent materials for solid-state lighting and color-conversion applications; however, their photoluminescence efficiency in the solid state is often limited by aggregation-induced quenching phenomena. In this work, we systematically investigate the role of the molar precursor ratio on the optical properties of green-emitting carbon dots, with the aim of establishing a direct link between synthesis parameters, photoluminescence optimization, and device-level performance. By carefully tuning the precursor ratio during synthesis, a significant enhancement of photoluminescence intensity and a strong suppression of solid-state quenching are achieved while preserving spectral stability in the green region. The optimized carbon dots exhibit improved radiative recombination and favorable optical characteristics for solid-state integration. Building on these results, the carbon dots are successfully employed as color-conversion layers in the fabrication of green light-emitting diodes, demonstrating efficient green emission under electrical excitation. This study highlights precursor ratio engineering as a simple and effective strategy to tailor carbon dot photoluminescence and provides a clear pathway from materials optimization to the realization of green color-conversion LED devices. Full article

The rapidly increasing demand for compact, high-performance beam-steering solutions in LiDAR systems has driven substantial advances in vertical-cavity surface-emitting laser (VCSEL) technologies. In this paper, we present a high-power, ultra-low-divergence VCSEL-based beam scanner array that integrates multi-wavelength seed lasers with extended-length optical amplifiers, thereby simultaneously achieving wide-angle beam steering, near-diffraction-limited beam quality, and watt-class output power. The proposed architecture exploits slow-light modes supported by laterally extended VCSEL waveguides incorporating precisely engineered surface gratings. This design enables fully electronic beam steering over an angular range exceeding 30°, with an angular resolution surpassing 1600 resolvable points. Systematic characterization of seed lasers with distinct grating periods confirms robust single-mode operation and yields a cumulative wavelength tuning range exceeding 22 nm. When integrated with optical amplifiers up to 6 mm in length, the system achieves a record-low beam divergence of 0.018°, approaching the theoretical diffraction limit. Under continuous-wave operation and without active thermal management, the device delivers output powers exceeding 1.6 W. By overcoming the long-standing trade-offs among steering range, beam quality, and output power, this work establishes a transformative paradigm for compact VCSEL-based beam-steering systems and represents a significant step toward next-generation solid-state LiDAR technologies. Full article

In this study, a double-lattice photonic crystal structure was designed to achieve deep ultraviolet lasing without the use of any Distributed Bragg Reflector (DBR), which is called a photonic-crystal surface-emitting laser (PCSEL). The plane wave expansion (PWE) method was used to study the influence of various structural parameters on the resonant wavelength. Utilizing the random forest algorithm, we determined that the importance of the lattice constant to the resonant wavelength is 95.24%. Furthermore, we realized the reverse design of double-lattice photonic crystals from the target wavelength to optimal structural parameters through a radial basis function (RBF) network algorithm. Comparative analysis of the extreme learning machine (ELM) and back propagation (BP) algorithms demonstrated that RBF-based performance was notably superior to the training outcomes of other algorithms. The mean absolute error (MAE) of the lattice constant of the test set in the training results was 0.7610 nm, root mean square error (RMSE) was $1.143\times {10}^{-3}$ nm, and mean absolute relative error (MARE) was $5.489\times {10}^{-3}$. We verified the reliability of the algorithm and designed 13 groups of photonic crystals with different epitaxial structures. The mean square error (MSE) was 0.6188 ${\mathrm{nm}}^2$ compared with that of the plane wave expansion method. This work demonstrates applicability across various wavebands and epitaxial structures in GaN-based devices, providing a novel approach for the rapid iteration of deep ultraviolet PCSELs. Full article