Unidirectional Transmission Metasurfaces with Topological Continuity Generated from High-dimensional Design Space.

With the growing demand for nanodevices, there is a concerted effort to improve the design flexibility of nanostructures, thereby expanding the capabilities of nanophotonic devices. In this work, a Laplacian-weighted binary search (LBS) algorithm is proposed to generate a unidirectional transmission metasurface from a high-dimensional design space, offering an increased degree of design freedom. The LBS algorithm incorporates topological continuity based on the Laplacian, effectively circumventing the common issue of high structural complexity in designing high-dimensional nanostructures. As a result, metasurfaces developed using the LBS algorithm in a high-dimensional design space exhibit reduced complexity, which is advantageous for experimental fabrication. An all-dielectric metasurface with unidirectional transmission, designed from the high-dimensional space using the LBS method, demonstrated the successful application of these design principles in experiments. The metasurface exhibits high optical performance on unidirectional transmission in measurements by a high-resolution angle-resolved micro-spectra system, achieving forward transmissivity above 90% (400-700 nm) and back transmissivity below 20% (400-500 nm) within the targeted wavelength range. This work provides a feasible approach for advancing high-dimensional metasurface applications, as the LBS design method takes into account topological continuity during experimental processing. Compared to traditional direct binary search (DBS) methods, the LBS method not only improves information processing efficiency but also maintains the topological continuity of structures. Beyond unidirectional transmission, the LBS-based design method has generality and flexibility to accommodate almost all physical scenarios in metasurface design, enabling a multitude of complex functions and applications.

Innovative OPA-based optical chip for enhanced digital holography.

Digital holographic imaging has emerged as a transformative technology with significant implications for AR/VR devices. However, existing techniques often suffer from limitations such as restricted field of view (FOV), high power consumption, and contrast distortion. This paper introduces an innovative optical phased array (OPA)-based chip, integrating polarization, amplitude, and phase multiplexing for enhanced complex amplitude holographic imaging. A checkerboard-style staggered array is employed in the control strategy, substantially reducing power consumption and enabling the potential for large-scale array integration. To further enhance imaging quality, we introduce what we believe are two novel calibration strategies: one is to achieve super-resolution through block imaging methods, and the other is to image using sparse aperture methods. These advancements not only provide a robust foundation for high-quality holographic imaging, but also present a new paradigm for overcoming the inherent limitations of current active holographic imaging devices. Due to challenges in chip fabrication, the research is primarily simulation-based. Nevertheless, this work presents meaningful advancements in digital holographic imaging for AR/VR applications and provides a foundation for future experimental validations.

PKD1 participates in the processing of aortic dissection via regulating vascular smooth muscle cell contraction and MAPK signaling.

Aortic Dissection (AD) is a cardiovascular emergency with high mortality, of which one feature is the phenotypic switch of vascular smooth muscle cells (VSMCs). Transient Receptor Potential Channel Interacting (PKD1) has been regarded as one regulator as well as one biomarker for AD. However, multiple candidate pathways were reported though which PKD1 regulates AD in previous study, a comprehensive insight is still absent. In this study, we compared the AD and normal samples in transcriptome scale, and detected 717 PKD1-related differential expressed genes, which enriched in mitogen-activated protein kinase (MAPK) signal transduction (AD tissue preference) and VSMC contraction pathway (normal tissue preference). Furthermore, we also found two important functional hub genes in PKD1 regulation, JUN and ACTN2, and established a carnal-miRNA-mRNA network. Our study demonstrated the co-regulation of muscle development and signal transduction in AD's progression, and also provided the genetic basis for the following mechanism research with AD.

Potential biomarkers of aortic dissection based on expression network analysis.

BACKGROUND: Aortic dissection (AD) is a rare disease with severe morbidity and high mortality. Presently, the pathogenesis of aortic dissection is still not completely clear, and studying its pathogenesis will have important clinical significance. METHODS: We downloaded 28 samples from the Gene Expression Omnibus (GEO) database (Accession numbers: GSE147026 and GSE190635), including 14 aortic dissection samples and 14 healthy controls (HC) samples. The Limma package was used to screen differentially expressed genes. The StarBasev2.0 tool was used to predict the upstream molecular circRNA of the selected miRNAs, and Cytoscape software was used to process the obtained data. STRING database was used to analyze the interacting protein pairs of differentially expressed genes under medium filtration conditions. The R package "org.hs.eg.db" was used for functional enrichment analysis. RESULTS: Two hundred genes associated with aortic dissection were screened. Functional enrichment analysis was performed based on these 200 genes. At the same time, 2720 paired miRNAs were predicted based on these 200 genes, among which hsa-miR-650, hsa-miR-625-5p, hsa-miR-491-5p and hsa-miR-760 paired mRNAs were the most. Based on these four miRNAs, 7106 pairs of circRNAs were predicted to be paired with them. The genes most related to these four miRNAs were screened from 200 differentially expressed genes (CDH2, AKT1, WNT5A, ADRB2, GNAI1, GNAI2, HGF, MCAM, DKK2, ISL1). CONCLUSIONS: The study demonstrates that miRNA-associated circRNA-mRNA networks are altered in AD, implying that miRNA may play a crucial role in regulating the onset and progression of AD. It may become a potential biomarker for the diagnosis and treatment of AD.

High accurate self-calibration of photonic integrated circuit using lossless thermo-optic phase shifters.

The accurate calibration of large-scale switch networks is critical for integrated photonics, in which the integrated optical true time delay chip is typical. In this work, a novel self-calibration method without extra testing ports is proposed by introducing lossless thermo-optic phase shifters instead to calibrate the network. As a demonstration, a 5-bit delay line based on silicon nitride is fabricated and calibrated. The extinction ratio of all the switches is greater than 30.9 dB at the cross and bar states. Using this method, the 5-bit optical delay line which can be tuned in a range of 118.53 ps and reach a low delay time deviation less than ±0.4 ps.

Series of ultra-low loss and ultra-compact multichannel silicon waveguide crossing.

Ultra-compact waveguide crossing (UC-WC) is a basic component in optoelectronic fusion chip solutions, as its footprint is smaller in the orders of magnitude than that of traditional photonic integrated circuits (PICs). However, a large loss of UC-WC (decibel level) becomes a barrier to scaling and practicality. Here, we propose a series of ultra-low loss UC-WC silicon devices using an advanced hybrid design that combines the adjoint method with the direct binary search (DBS) algorithm. Simulation results show that our 2 × 2 UC-WC has an insertion loss as low as 0.04 dB at 1550 nm, which is about ten times lower than the previous UC-WC results. In the valuable C-band (1530-1565 nm), the insertion loss of UC-WC is lower than -0.05 dB, and the channel crosstalk is lower than -34 dB. Furthermore, for the 3 × 3 UC-WC device, the highest insertion loss in the entire C-band is approximately -0.07 dB, and the highest channel crosstalk is lower than -33 dB. Additionally, the 4 × 4 and more complex 8 × 8 UC-WC devices were also analyzed. The highest insertion loss for 4 × 4 and 8 × 8 UC-WC in the C-band is only -0.19 dB and -0.20 dB, respectively, and the highest channel crosstalk is approximately -22dB and -28 dB, respectively. These results confirm that the designed devices possess two attractive features simultaneously: ultra-compactness and ultra-low insertion loss, which may be of great value in future large-scale optoelectronic fusion chips.

Ultra-low loss SiN edge coupler interfacing with a single-mode fiber.

In this work, an ultra-low loss silicon nitride (SiN) edge coupler was designed and fabricated to interface with a single-mode fiber (SMF). Unlike other works that focus on the core structure, this work focuses on the cladding structure. First, it is demonstrated that the cladding structure ultimately determines the size and shape of the mode when the taper tip width is small enough. Then, the thickness of the up-cladding is optimized to provide enough space for mode expansion in the vertical direction. Air trenches are added to confine the mode laterally. In addition, the refractive index (RI) of the up-cladding layer is slightly increased to prevent light from leaking into the Si substrate. This edge coupler is then fabricated on the SiN platform at Chongqing United Microelectronics Center. For the TE mode at 1630 nm, a coupling loss of 0.67 dB/facet was obtained. At 1550 nm, 0.85 dB/facet and 1.09 dB/facet were measured for the TE and TM modes, respectively, which means that the polarization-dependent loss is 0.24 dB. Although the design method and the structure are based on a pure SiN platform, they are applicable to a silicon-on-insulator platform as well.

High precision reconstruction of silicon photonics chaos with stacked CNN-LSTM neural networks.

Silicon-based optical chaos has many advantages, such as compatibility with complementary metal oxide semiconductor (CMOS) integration processes, ultra-small size, and high bandwidth. Generally, it is challenging to reconstruct chaos accurately because of its initial sensitivity and high complexity. Here, a stacked convolutional neural network (CNN)-long short-term memory (LSTM) neural network model is proposed to reconstruct optical chaos with high accuracy. Our network model combines the advantages of both CNN and LSTM modules. Further, a theoretical model of integrated silicon photonics micro-cavity is introduced to generate chaotic time series for use in chaotic reconstruction experiments. Accordingly, we reconstructed the one-dimensional, two-dimensional, and three-dimensional chaos. The experimental results show that our model outperforms the LSTM, gated recurrent unit (GRU), and CNN models in terms of MSE, MAE, and R-squared metrics. For example, the proposed model has the best value of this metric, with a maximum improvement of 83.29% and 49.66%. Furthermore, 1D, 2D, and 3D chaos were all significantly improved with the reconstruction tasks.

Reconfigurable spot size converter for the silicon photonics integrated circuit.

Spot size converter (SSC) plays a role of paramount importance in the silicon photonics integrated circuit. In this article, we report the design of a reconfigurable spot size converter used in the hybrid integration of a DFB laser diode with a silicon photonic waveguide. Our SSC consists of subwavelength gratings and thermal phase shifters. Four subwavelength grating tips are used to improve horizontal misalignment tolerance. Meanwhile, the phase mismatch between two input waveguides is compensated by phase shifters to minimize insertion losses. Our simulated result has yielded a minimum insertion loss of 0.63 dB and an improvement of the horizontal misalignment from ±0.65 µm to ±1.69 µm for 1 dB excess insertion loss at the wavelength of 1310 nm. The phase shifters are designed to compensate any phase error in both the fabrication and bonding processes, which provides a completely new edge-coupling strategy for the silicon photonics integrated circuit.

WWP2 ameliorates acute kidney injury by mediating p53 ubiquitylation and degradation.

E3 ubiquitin ligase gene, WWP2, is associated with acute kidney injury (AKI). This research was conducted to explore the role of WWP2 in AKI. AKI cell model was produced in human renal proximal tubular epithelial cell line (HK-2) by ischemia-reperfusion (IR) injury. CCK8 and flow cytometry assay were performed to explore the influence of WWP2 overexpression on cell proliferation and apoptosis of IR-induced HK-2 cells. Quantitative real-time PCR and immunoblotting (IB) were performed to assess the gene and protein expression. Then, the influence of WWP2 on p53 ubiquitylation and degradation was estimated by immunoprecipitation assay. Our data indicated that WWP2 was down-regulated and p53 was up-regulated in IR-induced HK-2 cells. WWP2 overexpression promoted proliferation and inhibited apoptosis of IR-induced HK-2 cells. And WWP2 interacted with p53 and regulated p53 ubiquitylation and degradation. Furthermore, the influence of WWP2 on cell proliferation and apoptosis was rescued by MG132 (proteasome inhibitor) treatment. In conclusion, our work described for the first time the role of WWP2 in AKI, showing that WWP2 ameliorated AKI by mediating p53 ubiquitylation and degradation. Moreover, the study offers some important insights into the occurrence of AKI and WWP2 may be a novel target of AKI treatment. SIGNIFICANCE OF THE STUDY: Our data elaborates that WWP2 has protective effect against AKI by mediating p53 ubiquitylation and degradation. Thus, WWP2 might be a therapeutic target for AKI.

LncRNA NRON alleviates atrial fibrosis via promoting NFATc3 phosphorylation.

The aim of this study was to explore the role of NRON in the atrial fibrosis. The expression of NRON in atrial tissue was detected using qRT-PCR. The protein levels of collagen I, collagen III, NFATc3 and p-NFATc3 were determined by western blot. Immunohistochemistry assay were performed to observe expression and distribution of collagen I in atrial tissues. The atrial fibroblasts were authenticated by vimentin/troponin immunofluorescence staining. Fibroblast proliferation was detected by CCK-8 assay. The morphological changes of cardiac tissue were observed by HE staining. Myocardial fibrosis was detected by masson staining. NRON expression was significantly downregulated in atrial tissues of AF. NRON suppressed fibroblast proliferation; expression of collagen I and collagen III; activation of NFATc3 and nucleu import. NRON promoted p-NFATc3 expression and alleviated atrial fibrosis in vivo. Our data indicated that NRON alleviates atrial fibrosis via promoting NFATc3 phosphorylation.

Experimental demonstration of ultracompact air hole photonic crystal ring resonator fabricated on silicon-on-insulator wafer.

A photonic crystal ring resonator (PCRR) of air hole arrays is fabricated on a silicon-on-insulator wafer by using electron-beam lithography and inductively coupled plasma etching. The designed PCRR is modeled and its performance is simulated by the two-dimensional finite difference time domain method. The simulation results show that the PCRR has two resonant wavelengths, 1598 and 1606 nm, and their corresponding quality factors are 3994 and 4015, respectively. A sample of the PCRR structure is fabricated and tested by the established experimental setup. Compared with the simulation results, the experimental resonant wavelengths drift to some extent and the quality factors are reduced by about one order of magnitude. The fabrication error and irregularity are the main reasons for the above results, which can be further reduced by improving the process technology. In addition, one more resonant wavelength emerged for the PCRR sample, which can be attributed to the change of the coupling strength.

Efficacy and Safety of Renal Function on Edoxaban Versus Warfarin for Atrial Fibrillation: A Systematic Review and Meta-Analysis.

Background: Edoxaban is a novel oral anticoagulant which may decrease the risk of stroke and systemic embolism in patients suffering from atrial fibrillation (AF). However, the decreased efficacy of edoxaban versus warfarin for the avoidance of stroke and systemic embolism in AF with creatinine clearance (CrCl) > 95 mL/min has been reported. The purpose of this meta-analysis is to further clarify the safety (major bleeding) and efficacy (stroke or systemic embolism) of edoxaban for AF patients with various CrCl. Methods: A systematic search of studies on edoxaban and warfarin in AF patients related to renal function was conducted in PubMed, Medline, Web of Science databases, EBSCO, Embase, and the Cochrane Central Register of Controlled Trials. In this meta-analysis (protocol number: PROSPERO CRD 42021245512), we included studies that provide specific data on three outcomes: ischemic stroke or systemic embolism (S/SE), bleeding, and all-cause mortality. Results: This meta-analysis enrolled two randomized controlled trials (RCTs) studies and two retrospective studies that enrolled 28,065 patients. According to CrCl, subjects are divided into three groups (CrCl 30−50 mL/min, CrCl 50−95 mL/min, CrCl > 95 mL/min). In AF patients with CrCl 30−50 mL/min, edoxaban 30 mg daily is similar to warfarin in the prevention of ischemic S/SE and all-cause mortality, resulting in lower bleeding rate and better net clinical outcome (ischemic S/SE: hazard ratio (HR), 0.85, 95% confidence interval (CI), 0.19−1.87; all-cause mortality: HR, 0.65, 95% CI, 0.35−1.19; bleeding: HR, 0.75, 95% CI, 0.60−0.93; net clinical outcome: HR, 0.75, 95% CI, 0.63−0.90). In the group of CrCl 50−95 mL/min, the net clinical outcome was more favorable with edoxaban 60 mg daily than warfarin (HR, 0.81, 95% CI: 0.68−0.96), and there was no significant difference between edoxaban 60 mg daily and warfarin in terms of prevention of bleeding, ischemic S/SE, and all-cause mortality. For AF patients with CrCl > 95 mL/min, there was a statistically significant difference in lower bleeding rate between edoxaban 60 mg daily and warfarin (bleeding: HR: 0.70, 95% CI: 0.58−0.84). There was no differential safety in ischemic S/SE, all-cause mortality, and net clinical outcome. Conclusion: Overall, edoxaban was superior to warfarin in terms of net clinical outcome in various groups of CrCl with AF patients. Although there was no significant difference in net clinical outcome between edoxaban and warfarin for AF patients with CrCl > 95 mL/min, edoxaban is not inferior to warfarin in safety and effectiveness in the various levels of CrCl. Edoxaban may be a more effective and safe treatment than warfarin for patients with chronic kidney disease (CKD) who require anticoagulation. More high-quality and long-term clinical research are needed to further estimate the effects of edoxaban.

A modified aortic arch "island anastomosis" with stent graft technique for acute type A aortic dissection: a retrospective analysis.

BACKGROUND: A modified aortic arch "island anastomosis" with a stent graft technique was used in 33 patients with acute type A aortic dissection. We retrospectively reviewed our experience of this procedure and the short-term follow-up results. METHODS: This retrospective analysis included 33 patients with acute type A aortic dissection undergoing the modified aortic arch island anastomosis with stent graft procedure. Postoperatively, computed tomography angiography images were obtained before discharge and at 12 months. RESULTS: All patients underwent successful surgery without intraoperative death. Three patients received dialysis because of postoperative renal insufficiency, 1 patient received tracheotomy because of postoperative respiratory insufficiency, and 5 patients had postoperative delirium. Surgery caused stroke in 1 patient. No paraplegia was found, and no re-exploration for bleeding was performed. One patient died in the hospital due to multiple organ failure, and the other patients were discharged as expected. Only 1 patient had a proximal endoleak, and the patient was stable under close follow-up. The diameter of the descending thoracic aorta was smaller at 12 months postoperatively than preoperatively (34.5±2.5 mm versus 36.7±2.9 mm, P<0.05). The average diameter of the true lumen of the descending thoracic aorta was larger at 12 months postoperatively than preoperatively (24.1±3.1 mm versus 14.9±2.3 mm, P<0.05). CONCLUSIONS: The modified aortic arch island anastomosis with stent graft technique is a feasible and safety surgical strategy for acute type A aortic dissection. Short-term outcomes are satisfactory.

Ultra-Compact and Broadband Nano-Integration Optical Phased Array.

The on-chip nano-integration of large-scale optical phased arrays (OPAs) is a development trend. However, the current scale of integrated OPAs is not large because of the limitations imposed by the lateral dimensions of beam-splitting structures. Here, we propose an ultra-compact and broadband OPA beam-splitting scheme with a nano-inverse design. We employed a staged design to obtain a T-branch with a wavelength bandwidth of 500 nm (1300-1800 nm) and an insertion loss of -0.2 dB. Owing to the high scalability and width-preserving characteristics, the cascaded T-branch configuration can significantly reduce the lateral dimensions of an OPA, offering a potential solution for the on-chip integration of a large-scale OPA. Based on three-dimensional finite-difference time-domain (3D FDTD) simulations, we demonstrated a 1 × 16 OPA beam-splitter structure composed entirely of inverse-designed elements with a lateral dimension of only 27.3 µm. Additionally, based on the constructed grating couplers, we simulated the range of the diffraction angle θ for the OPA, which varied by 0.6°-41.6° within the wavelength range of 1370-1600 nm.

Co-packaged optics (CPO): status, challenges, and solutions.

Due to the rise of 5G, IoT, AI, and high-performance computing applications, datacenter traffic has grown at a compound annual growth rate of nearly 30%. Furthermore, nearly three-fourths of the datacenter traffic resides within datacenters. The conventional pluggable optics increases at a much slower rate than that of datacenter traffic. The gap between application requirements and the capability of conventional pluggable optics keeps increasing, a trend that is unsustainable. Co-packaged optics (CPO) is a disruptive approach to increasing the interconnecting bandwidth density and energy efficiency by dramatically shortening the electrical link length through advanced packaging and co-optimization of electronics and photonics. CPO is widely regarded as a promising solution for future datacenter interconnections, and silicon platform is the most promising platform for large-scale integration. Leading international companies (e.g., Intel, Broadcom and IBM) have heavily investigated in CPO technology, an inter-disciplinary research field that involves photonic devices, integrated circuits design, packaging, photonic device modeling, electronic-photonic co-simulation, applications, and standardization. This review aims to provide the readers a comprehensive overview of the state-of-the-art progress of CPO in silicon platform, identify the key challenges, and point out the potential solutions, hoping to encourage collaboration between different research fields to accelerate the development of CPO technology.

Thermo-optic phase shifters based on silicon-on-insulator platform: state-of-the-art and a review.

Silicon photonic platforms offer relevance to large markets in many applications, such as optical phased arrays, photonic neural networks, programmable photonic integrated circuits, and quantum computation devices. As one of the basic tuning devices, the thermo-optic phase shifter (TOPS) plays an important role in all these applications. A TOPS with the merits of easy fabrication, low power consumption, small thermal time constant, low insertion loss, small footprint, and low crosstalk, is needed to improve the performance and lower the cost of the above applications. To meet these demands, various TOPS have been proposed and experimentally demonstrated on different foundry platforms In this paper, we review the state-of-the-art of TOPS, including metal heater, doped silicon, silicide, with silicon substrate undercut for heat insulation, folded waveguide structure, and multi-pass waveguide structure. We further compare these TOPSs and propose the directions of the future developments on TOPS.

A Non-Volatile Tunable Ultra-Compact Silicon Photonic Logic Gate.

Logic gates, as one of the most important basic units in electronic integrated circuits (EICs), are also equally important in photonic integrated circuits (PICs). In this study, we proposed a non-volatile, ultra-compact all-photonics logic gate. The footprint is only 2 µm × 2 µm. We regulate the phase change of optical phase change materials(O-PCMs) Sb2Se3 to switch the function of the logic gate. The Sb2Se3 possess a unique non-volatile optical phase change function; therefore, when Sb2Se3 is in the crystalline or amorphous state, our device can work as XOR gate or AND gate, and our designed logic '1' and logic '0' contrasts reach 11.8 dB and 5.7 dB at 1550 nm, respectively. Compared with other traditional optical logic gates, our device simultaneously has non-volatile characteristics, tunability, and additionally an ultra-small size. These results could fully meet the needs of fusion between PICs and EICs, and developing truly chip-scale optoelectronic logic solution.

Mechanical valve replacement without anticoagulation: a case report.

BACKGROUND: For patients who undergo mechanical valve replacement, the greatest disadvantage is that they require long-term or permanent use of anticoagulant therapy to prevent thromboembolism. To date, mechanical valve replacement without anticoagulation has been published in the literature. CASE SUMMARY: We present the case of a 75-year-old female who underwent mechanical mitral valve replacement (MVR) on mid-June, 2007. However, this patient had not been taking anticoagulant medication since she experienced warfarin overdose in the first month after the operation. She had been well without using any anticoagulation, and there were no complications of the mechanical valve. DISCUSSION: There was no thrombosis for such a long period of time because she suffered from FX deficiency. To the best of our knowledge, she may be the only patient who has been well without any anticoagulation since not taking warfarin 12 years ago.

Compact and low cross-talk silicon-on-insulator crossing using a periodic dielectric waveguide.

We propose and experimentally demonstrate a compact, highly efficient, and negligible cross-talk silicon-on-insulator crossing using a periodic dielectric waveguide. The crossing occupies a footprint of less than 4 µm × 4 µm. Around 0.7 dB insertion loss and lower than -40 dB, cross talk was achieved experimentally over a broad wavelength range.