Metasurfaces offer complete control of optical wavefront at the subwavelength scale, advancing a new class of artificial planar optics, including lenses, waveplates, and holograms, with unprecedented ...merits over conventional optical components. In particular, the ultrathin, flat, and compact characteristics of metasurfaces facilitate their integration with semiconductor devices for the development of miniaturized and multifunctional optoelectronic systems. In this work, generation of structured light is implemented at an ultracompact wafer‐level through the monolithic integration of metasurface with standard vertical cavity surface‐emitting lasers (VCSELs). This work opens new perspectives for the design of structured light systems with compactness, lightweight, and scalability. Ultracompact beam structured laser chips with versatile functionalities are experimentally demonstrated, including multichannel beams array generation, on‐chip large‐angle beam steering up to 60°, and wafer‐level holographic beam shaping with a wide field of view (about 124°). The results will promote the development of compact light structuring systems with great potential in 3D imaging, displays, robotic vision, human–computer interaction, and augmented/virtual reality.
On‐chip generation of structured light is demonstrated via monolithic integration of dielectric metasurfaces with standard vertical cavity surface‐emitting lasers (VCSELs). This new type of ultracompact beam structuring chip exhibits versatile functionalities, including multichannel beams array generation, on‐chip large‐angle beam steering up to 60°, and wafer‐level holographic beam shaping with a wide field of view.
Metasurface polarization optics that consist of 2D array of birefringent nano‐antennas have proven remarkable capabilities to generate and manipulate vectorial fields with subwavelength resolution ...and high efficiency. Integrating this new type of metasurface with the standard vertical cavity surface‐emitting laser (VCSEL) platform enables an ultracompact and powerful solution to control both phase and polarization properties of the laser on a chip, which allows to structure a VCSEL into vector beams with on‐demand wavefronts. Here, this concept is demonstrated by directly generating versatile vector beams from commercially available VCSELs through on‐chip integration of high‐index dielectric metasurfaces. Experimentally, the versatility of the approach for the development of vectorial VCSELs are validated by implementing a variety of functionalities, including directional emission of multibeam with specified polarizations, vectorial holographic display, and vector vortex beams generations. Notably, the proposed vectorial VCSELs integrated with a single layer of beam shaping metasurface bypass the requirements of multiple cascaded optical components, and thus have the potential to promote the advancements of ultracompact, lightweight, and scalable vector beams sources, enriching and expanding the applications of VCSELs in optical communications, laser manipulation and processing, information encryption, and quantum optics.
On‐chip generation and manipulation of vector beams are demonstrated by monolithically integrating vectorial metasurfaces with standard vertical cavity surface‐emitting lasers (VCSELs). The developed approach enables a powerful tool to structure the complex wavefronts of a VCSEL in an ultracompact way, providing the access to previously unattainable both phase and polarization degrees of freedom.
Glass lubricant with a suitable viscosity is essential for producing high‐quality titanium products by the hot extrusion process. In this study, a novel lubricant of B2O3–SiO2–Al2O3–Na2O–TiO2 (BSANT) ...glass was proposed, where the effects of B2O3/SiO2 molar ratio (B/Si) and B2O3 content on viscosity and structure were investigated. The results showed that the BSANT glass viscosity was gradually decreased, and the viscous activation energy was decreased by 20.24% with an increased B/Si ratio from 0.415 to 0.719. This was attributed to the decreased amounts of Q3, BO4, AlO4, and bridging oxygen (BO) in the network structure, which in turn resulted in a decreased network degree of polymerization. When B2O3 content was increased from 18.70 to 33.12 mol.%, the melt viscosity value at 950 ℃ was decreased by 64.51%, and the viscous activation energy was reduced by 15.82%. Boron anomalies were also observed in glass melts with the B2O3 content from 28.28 to 33.12 mol.%. The mechanisms responsible for this phenomenon were thoroughly discussed in the study. Additionally, a comparison and discussion of the applications of glass lubricants in metal hot working were presented. A glass lubricant with a specific composition was recommended for use in hot extrusion process within the temperature range of 950–1100°C due to its relatively stable viscosity properties.
A novel lubricant of B2O3–SiO2–Al2O3–Na2O–TiO2 (BSANT) glass was proposed, where the effects of B2O3/SiO2 molar ratio (B/Si) and B2O3 content on viscosity and structure were investigated. A glass lubricant with a specific composition was recommended for use in hot extrusion process within the temperature range of 950–1100°C due to its relatively stable viscosity properties.
Polarization response of artificially structured nano-antennas can be exploited to design innovative optical components, also dubbed "vectorial metasurfaces", for the modulation of phase, amplitude, ...and polarization with subwavelength spatial resolution. Recent efforts in conceiving Jones matrix formalism led to the advancement of vectorial metasurfaces to independently manipulate any arbitrary phase function of orthogonal polarization states. Here, we are taking advantages of this formalism to design and experimentally validate the performance of CMOS compatible Jones matrix metasurfaces monolithically integrated with standard VCSELs for on-chip spin-decoupling and phase shaping. Our approach enables accessing the optical spin states of VCSELs in an ultra-compact way with previously unattainable phase controllability. By exploiting spin states as a new degree of freedom for laser wavefront engineering, our platform is capable of operating and reading-out the spin-momentum of lasers associated with injected spin carriers, which would potentially play a pivotal role for the development of emerging spin-optoelectronic devices.
Genistein, a soy-derived phytoestrogen, has been shown to exhibit anti-neoplastic activities in various cancers. Nevertheless, its effects on the elimination of tumor-initiating cells of head and ...neck cancer (HNC-TICs) remain unclear. Here, we investigated the inhibitory effect of genistein on HNC-TICs and potential mechanisms. Our results demonstrated that genistein lowered the proliferation of HNC-TICs by examining the percentage of ALDH1+ or CD44+ cells. Aside from the downregulation of epithelial-mesenchymal transition (EMT) in HNC-TICs, genistein restricted their tumor propagating capacities in a dose-dependent fashion. Moreover, genistein potentiated cell death caused by three commonly used chemotherapeutic agents (doxorubicin, cisplatin, and 5-FU). Our findings proved that genistein induced ROS production through upregulation of miR-34a, leading to apoptosis in HNC-TICs. The genistein-elicited miR-34a reduced self-renewal, migration, invasion capacities and ALDH1 activity, which may be partly owing to the repression of EMT. Furthermore, we showed that RTCB was a novel target that was negatively regulated by miR-34a and involved in the tumor repressive effect of genistein. Besides, the in vivo study validated that genistein retarded tumor growth through the elevation of miR-34a and suppression of RTCB. These results suggested that genistein-induced miR-34a contributed to the ROS-associated apoptosis and diminished stemness properties via repression of RTCB in HNC-TICs.
Background/Aims: Protodioscin (PD) is a steroidal saponin with anti-cancer effects on a number of cancer cells, but the anti-tumor effects and mechanism of action of PD on human cervical cancer cells ...is unclear. Methods: We determined cell viability using the MTT assay. Cell death, mitochondrial membrane potential (MMP), intracellular reactive oxygen species (ROS) generation, and endoplasmic reticulum (ER) stress were measured on a flow cytometry. Caspase activation, ER stress, and MMP-dependent apoptosis proteins in cervical cancer cells in response to PD were determined by Western blot analysis. The ability of ATF4 binding to ChIP promoter was measured using the ChIP assay. Results: We demonstrated that PD inhibits cell viability, causes a loss of mitochondrial function, and induces apoptosis, as evidenced by up-regulation of caspase-8, -3, -9, -PARP, and Bax activation, and down-regulation of Bcl-2 expression. PD was shown to induce ROS and the ER stress pathway, including GRP78, p-eIF-2α, ATF4, and CHOP. Pre-treatment with NAC, a ROS production inhibitor, significantly reduced ER stress and apoptosis-related proteins induced by PD. Transfection of GRP78/CHOP-siRNA effectively inhibited PD-induced ER stress-dependent apoptosis. Moreover, treatment with PD significantly increased p38 and JNK activation. Co-administration of a JNK inhibitor (SP600125) or p38 inhibitor (SB203580) abolished cell death and ER stress effects during PD treatment. In addition, PD induced the expression of nuclear ATF4 and CHOP, as well as the binding ability of ATF4 to the CHOP promoter. Conclusion: Our results suggest that PD is a promising therapeutic agent for the treatment of human cervical cancer.
The cathodic material plays an essential role in oxygen reduction reaction for energy conversion and storage systems. Titanium dioxide, as a semiconductor material, is usually not recognized as an ...efficient oxygen reduction electrocatalyst owning to its low conductivity and poor reactivity. Here we demonstrate that nano-structured titanium dioxide, self-doped by oxygen vacancies and selectively exposed with the high-energy {001} facets, exhibits a surprisingly competitive oxygen reduction activity, excellent durability and superior tolerance to methanol. Combining the electrochemical tests with density-functional calculations, we elucidate the defect-centred oxygen reduction reaction mechanism for the superiority of the reductive {001}-TiO2-x nanocrystals. Our findings may provide an opportunity to develop a simple, efficient, cost-effective and promising catalyst for oxygen reduction reaction in energy conversion and storage technologies.
Organic Fenton-like catalysis has been recently developed for water purification, but redox-active compounds have to be ex situ added as oxidant activators, causing secondary pollution problem. ...Electrochemical oxidation is widely used for pollutant degradation, but suffers from severe electrode fouling caused by high-resistance polymeric intermediates. Herein, we develop an in situ organic Fenton-like catalysis by using the redox-active polymeric intermediates, e.g., benzoquinone, hydroquinone, and quinhydrone, generated in electrochemical pollutant oxidation as H₂O₂ activators. By taking phenol as a target pollutant, we demonstrate that the in situ organic Fenton-like catalysis not only improves pollutant degradation, but also refreshes working electrode with a better catalytic stability. Both ¹O₂ nonradical and ·OH radical are generated in the anodic phenol conversion in the in situ organic Fenton-like catalysis. Our findings might provide a new opportunity to develop a simple, efficient, and cost-effective strategy for electrochemical water purification.
Three‐dimensional echocardiography allows for presurgical planning for congenital heart disease, reduces radiation using fusion imaging in catheter interventions, and provides guidance during ...catheter interventions and lead placements or extractions. The purpose of this review is to detail applications of three‐dimensional transesophageal echocardiography in presurgical planning of congenital heart disease, guidance of catheter interventions such as fusion imaging, and guidance in electrophysiology lead extractions or placements.
PDF
