Orbital Angular Momentum Mode Multiplexer Based on Multimode Micro-Ring Resonator with Angular Gratings

We demonstrate silicon photonic orbital angular momentum multiplexing devices based on mulitmode microring resonator. Up to four optical beams carrying different orbital angular momentum states can be selectively excited from different input ports

Orbital angular momentum vector modes (de)multiplexer based on multimode micro-ring

Orbital angular momentum (OAM) multiplexing has emerged as an important method to increase the communication capacities in future optical information technologies. In this work, we demonstrate a silicon integrated OAM (de)multiplexer with a very simple structure. By simply tapping the evanescent wave of two different whispering gallery modes rotating inside a multimodal micro-ring resonator, four in-plane waveguide modes are converted to four free-space vector OAM beams with high mode purity. We further demonstrate chip-to-chip OAM multiplexing transmission using a pair of silicon devices, which shows low-level mode crosstalk and favorable link performance

Integrated optical vortex beam receivers

A simple and ultra-compact integrated optical vortex beam receiver device is presented. The device is based on the coupling between the optical vortex modes and whispering gallery modes in a micro-ring resonator via embedded angular gratings, which provides the selective reception of optical vortex modes with definitive total angular momentum (summation of spin and orbital angular momentum) through the phase matching condition in the coupling process. Experimental characterization confirms the correct detection of the total angular momentum carried by the vortex beams incident on the device. In addition, photonic spin-controlled unidirectional excitation of whispering-gallery modes in the ring receiver is also observed, and utilized to differentiate between left- and right-circular polarizations and therefore unambiguously identify the orbital angular momentum of incident light. Such characteristics provide an effective mode-selective receiver for the eigen-modes in orbital angular momentum fiber transmission where the circularly polarized OAM modes can be used as data communications channels in multiplexed communications or as photonic states in quantum information applications

High-directional vortex beam emitter based on Archimedean spiral adiabatic waveguides

Integrated devices that emit light beams with orbital angular momentum (OAM) are becoming key components for wide-ranging applications. Here we propose and demonstrate a highly directional silicon photonic vortex beam emitter based on a 3-turn Archimedean spiral adiabatic waveguide integrated with an angular grating. Such a compact emitter is capable of generating vortex beams with small divergence angles and high directivity. Various orders of OAM modes can be selectively generated by the emitter at different wavelengths with a side-mode suppression ratio as large as 13.6 dB

Catalytic regioselective acylation of unprotected nucleosides for quick access to COVID and other nucleoside prodrugs

Nucleosides have important therapeutic applications that include antiviral activities against COVID viruses. It is a common strategy to convert one or multiple of the hydroxyl (OH) units in nucleosides to the corresponding ester groups to prepare nucleoside prodrugs for better performance. Due to the presence of multiple OH units in nucleosides, current protocols for access to such ester prodrugs involve multiple steps due to installation and removal of protection groups. Here, we disclose a catalytic strategy that allows for regioselective functionalization of a specific OH unit without the need of protecting other OH groups. The key step in our method is an N-heterocyclic carbene-catalyzed selective acylation of the pentose unit of nucleosides. We demonstrate that commercially launched COVID-19 prodrugs such as molnupiravir can be prepared in concise routes by using our strategy.Ministry of Education (MOE)Nanyang Technological UniversityNational Research Foundation (NRF)Submitted/Accepted versionWe acknowledge the funding support from the National Natural Science Foundation of China (21732002, 21961006, 32172459, 22061007, 22071036), Frontiers Science Center for Asymmetric Synthesis and Medicinal Molecules, Department of Education, Guizhou Province [Qianjiaohe KY number (2020)004], the Science and Technology Department of Guizhou Province (Qiankehejichu-ZK[2021]Key033), Program of Introducing Talents of Discipline to Universities of China (111 Program, D20023) at Guizhou University, Singapore National Research Foundation under its NRF Investigatorship (NRF-NRFI2016-06) and Competitive Research Program (NRF-CRP22-2019-0002); the Singapore Ministry of Education under its MOE AcRF Tier 1 Award (RG7/20, RG5/19), MOE AcRF Tier 2 Award (MOE2019-T2-2-117), and MOE AcRF Tier 3 Award (MOE2018-T3-1-003), and Nanyang Technological University

Early presence of anti-angiogenesis-related adverse events as a potential biomarker of antitumor efficacy in metastatic gastric cancer patients treated with apatinib: a cohort study

Background: Reliable biomarkers of apatinib response in gastric cancer (GC) are lacking. We investigated the association between early presence of common adverse events (AEs) and clinical outcomes in metastatic GC patients. Patients and methods We conducted a retrospective cohort study using data on 269 apatinib-treated GC patients in two clinical trials. AEs were assessed at baseline until 28 days after the last dose of apatinib. Clinical outcomes were compared between patients with and without hypertension (HTN), proteinuria, or hand and foot syndrome (HFS) in the first 4 weeks. Time-to-event variables were assessed using Kaplan–Meier methods and Cox proportional hazard regression models. Binary endpoints were assessed using logistic regression models. Landmark analyses were performed as sensitivity analyses. Predictive model was analyzed, and risk scores were calculated to predict overall survival. Results: Presence of AEs in the first 4 weeks was associated with prolonged median overall survival (169 vs. 103 days, log-rank p = 0.0039; adjusted hazard ratio (HR) 0.64, 95% confidence interval [CI] 0.64–0.84, p = 0.001), prolonged median progression-free survival (86.5 vs. 62 days, log-rank p = 0.0309; adjusted HR 0.69, 95% CI 0.53–0.91, p = 0.007), and increased disease control rate (54.67 vs. 32.77%; adjusted odds ratio 2.67, p < 0.001). Results remained significant in landmark analyses. The onset of any single AE or any combinations of the AEs were all statistically significantly associated with prolonged OS, except for the presence of proteinuria. An AE-based prediction model and subsequently derived scoring system showed high calibration and discrimination in predicting overall survival. Conclusion: Presence of HTN, proteinuria, or HFS during the first cycle of apatinib treatment was a viable biomarker of antitumor efficacy in metastatic GC patients. Electronic supplementary material The online version of this article (10.1186/s13045-017-0521-0) contains supplementary material, which is available to authorized users

Facts about Ebola [Spanish]

Facts about Ebola [Spanish]Usted no puede contraer la enfermedad del \uc3\u2030bola por el aire.Usted no puede contraer la enfermedad del \uc3\u2030bola por el agua.Usted no puede contraerla enfermedaddel \uc3\u2030bola por los alimentos.Usted solo puede contraer la enfermedad del \uc3\u2030bola al tocar los l\uc3\uadquidos corporales de una persona enferma o que muri\uc3\ub3 por esta enfermedad, o al tocar objetos contaminados, como agujas. La enfermedad del \uc3\u2030bola no presenta un riesgo significativo en los Estados Unidos