Exceptionally High-glum Circularly Polarized Lasers Empowered by Strong 2D-Chiroptical Response in a Host-Guest Supramolecular Microcrystal.

Circularly polarized (CP) lasers hold tremendous potential for advancing spin information communication and display technologies. Organic materials are emerging candidates for high-performance CP lasers because of their abundant chiral structures and excellent gain characteristics. However, their dissymmetry factor (glum) in CP emission is typically low due to the weak chiral light matter interactions. Here, we presented an effective approach to significantly amplifying glum by leveraging the intrinsic 2D-chiroptical response of an anisotropic organic supramolecular crystal. The organic complex microcrystal was designed to exhibit large 2D-chiroptical activities through strong coupling interactions between their remarkable linear birefringence (LB) and high degree of fluorescence linear polarization. Such 2D-chiroptical response can be further enhanced by the stimulated emission resulted from an increased degree of linear polarization, yielding a nearly pure CP laser with an exceptionally high glum of up to 1.78. Moreover, exploiting the extreme susceptibility of LB to temperature, we demonstrate a prototype of temperature-controlled chiroptical switches. These findings offer valuable insights for harnessing organic crystals to facilitate the development of high-performance CP lasers and other chiroptical devices.

Photoelectrochemical Cells with a Pyridine-Anchored Bilayer Photoanode for Water Splitting.

A dye-sensitized photoanode is prepared by coassembling a Ru complex photosensitizer and a Ru water oxidation catalyst (WOC) on a TiO2 substrate, in which the WOC molecules are immobilized in a layer-by-layer fashion through metal-pyridine coordination with the aid of a bifunctional anchoring and bridging molecule containing multiple pyridine groups. Under visible-light irradiation, an anodic photocurrent of around 200 µA/cm2 has been achieved with O2 and H2 being generated at the photoanode and Pt counter electrode, respectively. The pyridine anchoring strategy provides a simple method to prepare photoelectrodes for applications in photoelectrochemical cells.

Referral to hepatologists or a second-line examination requirement is common in patients with type 2 diabetes mellitus.

BACKGROUND AND AIMS: To estimate the number of patients who required a referral to hepatologists following the 2016 EASL-EASD-EASO guideline and a second-line vibration controlled transient elastography (VCTE) examination following the 2021 EASL guideline according to obesity, glycated hemoglobin (HbA1c), blood pressure (BP), and low-density lipoprotein cholesterol (LDL-C) control status in patients with type 2 diabetes mellitus (T2DM). METHODS AND RESULTS: A total of 2515 T2DM patients who were hospitalized were cross-sectionally assessed. When we applied the 2016 EASL-EASD-EASO guideline, 26.8 %-46.4 % (depending on the scores used for diagnosing fibrosis) of T2DM patients needed a referral to hepatologists. When we applied the 2021 EASL guideline, a VCTE examination was required in 10.9 %-35 % (depending on the scores used for diagnosing fibrosis) of T2DM patients. The referral rates and the VCTE requirement were even higher in patients who were obese and/or had poor HbA1c, BP, and/or LDL-C control. CONCLUSIONS: Application of the screening guidelines would lead to a referral to hepatologists or a second-line VCTE examination requirement for a substantial number of T2DM patients, regardless of obesity and metabolic goal attainment status.

Geometry-Programmable Perovskite Microlaser Patterns for Two-Dimensional Optical Encryption.

Lasing signals with easily distinguishable readout and cavity-geometry-dependent output are emerging as novel cryptographic primitives for two-dimensional (2D) optical encryption, while their practical application is restricted by the challenge of integrating different lasing elements onto an identical 2D pattern. Herein, a lithographic template-confined crystallization approach was proposed to prepare large-scale perovskite microstructures with any desired geometries and locations, which enabled them to serve as 2D lasing patterns for reliable encryption and authentication. These prepatterned perovskite microstructures realized whispering-gallery-mode lasing and also demonstrated outstanding reproducibility of lasing actions. Benefiting from the feature of their cavity-geometry-dependent lasing thresholds, we achieved controllable laser output from different shaped elements, which was further utilized for the proof-of-concept demonstration of a cryptographic implementation. The remarkable lasing performance and feasible preparation of 2D microlaser patterns with customized geometries and locations provide us deep insights into the concepts and fabrication technologies for 2D optical encryption.

Thermally Activated Lasing in Organic Microcrystals toward Laser Displays.

Thermally activated delayed fluorescent (TADF) materials are promising to overcome triplet-induced optical loss in the pursuit of electrically pumped organic lasers. However, population inversion is difficult to establish in these materials due to the severe suppression of triplet-to-singlet upconversion in their condensed states. In this work, we report thermally activated lasing in solution-processed coassembled microcrystals, where TADF dyes were uniformly dispersed into crystalline matrices to ensure an efficient reverse intersystem crossing (RISC). The dark-state triplet excitons harvested by the RISC were effectively converted into radiative singlet excitons, which subsequently participated in the population inversion to boost lasing with an unusual temperature dependence. The lasing wavelength was tuned over the full visible spectrum by doping various TADF laser dyes, owing to the excellent compatibility. Trichromatic TADF microlasers were precisely patterned into periodic pixelated arrays by a template-confined solution-growth method. With as-prepared TADF microlaser arrays as display panels, vivid laser displays were achieved under programmable excitation. These results offer valuable enlightenment to minimize triplet state-related energy losses toward high-performance lasers.

Optically Pumped Lasing in Microscale Light-Emitting Electrochemical Cell Arrays for Multicolor Displays.

Laser displays, which offer wide achievable color gamut and excellent color rendering, have emerged as a promising next-generation display technology. Constructing display panels composed of pixelated microlaser arrays is of great significance for the actualization of laser displays in the flat-panel sector. Here, we report microscale light-emitting electrochemical cell (LEC) arrays that operate as both optically pumped lasers and electroluminescence devices, which can be applied as self-emissive panels for high quality displays. Optically pumped red, green, and blue laser emissions were achieved in individual circular microcells consisting of corresponding conjugated polymers and electrolytes, suggesting that the microstructures can act as resonators for coherent outputs. As-prepared microstructures possess a narrowed recombination region, which dramatically increases the current density by 3 orders of magnitude under pulsed operation, compared with the corresponding thin-film devices, representing a promising solution-processed device platform for electrical pumping. Under programmable electrical excitation, both static and dynamic displays were demonstrated with such microscale LEC arrays as display panels. The prominent performance of the demonstrated structures (microlaser arrays embedded in LEC devices) provide us deep insight into the concepts and device constructions of electrically driven laser displays.

Association of the insulin resistance marker TyG index with the severity and mortality of COVID-19.

BACKGROUND: The triglyceride and glucose index (TyG) has been proposed as a marker of insulin resistance. This study aims to evaluate the association of the TyG index with the severity and mortality of coronavirus disease 2019 (COVID-19). METHODS: The study included a cohort of 151 patients with COVID-19 admitted in a tertiary teaching hospital in Wuhan. Regression models were used to investigate the association between TyG with severity and mortality of COVID-19. RESULTS: In this cohort, 39 (25.8%) patients had diabetes, 62 (41.1%) patients were severe cases, while 33 (22.0%) patients died in hospital. The TyG index levels were significantly higher in the severe cases and death group (mild vs. severe 8.7 ± 0.6 vs. 9.2 ± 0.6, P < 0.001; survivor vs. deceased 8.8 ± 0.6 vs. 9.3 ± 0.7, P < 0.001), respectively. The TyG index was significantly associated with an increased risk of severe case and mortality, after controlling for potential confounders (OR for severe case, 2.9, 95% CI 1.2-6.3, P = 0.007; OR for mortality, 2.9, 95% CI 1.2-6.7, P = 0.016). The associations were not statistically significant for further adjustment of inflammatory factors. CONCLUSION: TyG index was closely associated with the severity and morbidity in COVID-19 patients, thus it may be a valuable marker for identifying poor outcome of COVID-19.

Hydrophobic Modification on the Surface of SiO2 Nanoparticle: Wettability Control.

Good control of the morphology, particle size, and wettability of silica nanoparticles is of increasing importance to their use in a variety of fields. Here, we propose a strategy to tune the surface wettability of nanosilica by changing the dosage of a chemical modifier. A series of measurements, including scanning electron microscopy (SEM), laser scatting technique, Fourier transform infrared (FTIR) spectroscopy, thermogravimetry, and surface hydroxyl number and water contact angle measurement, were conducted to verify the surface chemistry and wettability of these nanoparticles. Through controlled chemical modification, the contact angle of the treated nanoparticles increases from 34.7 to 155° with increasing amount of dichlorodimethylsilane (DCDMS) within a molar ratio (MR) between DCDMS and nanoparticles of 5.17. The number of hydroxyl groups covered on the particle surface decreases gradually from 1.79 to 0.47, and the surface grafting rate could reach 73.7%. As the addition of dichlorodimethylsilane equals MR 5.17, the contact angle reaches the maximum value of 155°, which displays excellent superhydrophobicity. After surpassing the point of MR 5.17, the contact angle does not increase but starts to decrease, ultimately remaining stable at 135°. It can be concluded that the surface wettability of nano-SiO2 particles can be precisely modulated by varying the amounts of the modifier. Furthermore, the modulating mechanism of the process occurring on the surface of SiO2 particles has been investigated at the molecular level.

CLINICAL CHARACTERISTICS OF 28 PATIENTS WITH DIABETES AND COVID-19 IN WUHAN, CHINA.

Objective: Previous studies on coronavirus disease 2019 (COVID-19) were based on information from the general population. We aimed to further clarify the clinical characteristics of diabetes with COVID-19. Methods: Twenty-eight patients with diabetes and COVID-19 were enrolled from January 29, 2020, to February 10, 2020, with a final follow-up on February 22, 2020. Epidemiologic, demographic, clinical, laboratory, treatment, and outcome data were analyzed. Results: The average age of the 28 patients was 68.6 ± 9.0 years. Most (75%) patients were male. Only 39.3% of the patients had a clear exposure of COVID-19. Fever (92.9%), dry cough (82.1%), and fatigue (64.3%) were the most common symptoms, followed by dyspnea (57.1%), anorexia (57.1%), diarrhea (42.9%), expectoration (25.0%), and nausea (21.4%). Fourteen patients were admitted to the intensive care unit (ICU). The hemoglobin A1c level was similar between ICU and non-ICU patients. ICU patients had a higher respiratory rate, higher levels of random blood glucose, aspartate transaminase, bilirubin, creatine, N-terminal prohormone of brain natriuretic peptide, troponin I, D-dimers, procalcitonin, C-reactive protein, ferritin, interleukin (IL)-2R, IL-6, and IL-8 than non-ICU patients. Eleven of 14 ICU patients received noninvasive ventilation and 7 patients received invasive mechanical ventilation. Twelve patients died in the ICU group and no patients died in the non-ICU group. Conclusion: ICU cases showed higher rates of organ failure and mortality than non-ICU cases. The poor outcomes of patients with diabetes and COVID-19 indicated that more supervision is required in these patients. Abbreviations: COVID-19 = coronavirus disease 2019; ICU = intensive care unit; MERS-CoV = middle East respiratory syndrome-related coronavirus; 2019- nCoV = 2019 novel coronavirus; NT-proBNP = N-terminal prohormone of brain natriuretic peptide; SARS-CoV = severe acute respiratory syndrome-related coronavirus.

Discrete Sliding Mode Control Design for Bilateral Teleoperation System via Adaptive Extended State Observer.

The goal of this paper is to improve the synchronization control performance of nonlinear teleoperation systems with system uncertainties in the presence of time delays. In view of the nonlinear discrete states of the teleoperation system in packet-switched communication networks, a new discrete sliding mode control (DSMC) strategy is performed via a new reaching law in task space. The new reaching law is designed to reduce the chattering and improve control performance. Moreover, an adaptive extended state observer (AESO) is used to estimate the total system disturbances. The additional gain of AESO is adjusted in time to decrease the estimation errors of both system states and disturbances automatically and improve the estimation performances of the AESO. Finally, the validity of the designed control strategy is demonstrated by both simulation and experiments. Furthermore, the experimental comparison results indicate that the improvement is achievable with the proposed AESO and DSMC.

Organic Printed Core-Shell Heterostructure Arrays: A Universal Approach to All-Color Laser Display Panels.

A universal approach is demonstrated for realizing dual-wavelength lasing in organic core-shell structured microlaser arrays, which show great promise in serving as all-color laser display panels. By alternately printing hydrophilic and hydrophobic laser dye solutions on preprocessed substrates, precisely patterned core-shell heterostructure arrays were obtained. The spatially separated core and shell independently function as optical resonators to support dual-wavelength tunable lasing in each heterostructure. Such a general method enables to flexibly control the lasing wavelength of the core-shell microlasers across a wide spectral range by systematically designing the gain media. Using as-prepared microlaser arrays as display panels, full-color laser displays were achieved with a color gamut much larger than that of standard RGB space. These results provide insights for design concepts and device construction for novel optoelectronic applications.

Spatially Responsive Multicolor Lanthanide-MOF Heterostructures for Covert Photonic Barcodes.

Micro/nanoscale photonic barcodes based on multicolor luminescent segmented heterojunctions hold potential for applications in information security. However, such multicolor heterojunctions reported thus far are exclusively based on static luminescent signals, thus restricting their application in advanced confidential information protection. Reported here is a strategy to design responsive photonic barcodes with heterobimetallic (Tb3+ /Eu3+ ) metal-organic framework multicolor heterostructures. The spatial colors could be precisely controlled by thermally manipulating the energy-transfer process between the two lanthanides, thus achieving responsive covert photonic barcodes. Also demonstrated is that spatially resolved responsive barcodes with multi-responsive features could be created in a single heterostructure. These findings offer unique opportunities to purposely design highly integrated responsive microstructures and smart devices toward advanced anti-counterfeiting applications.

Experimentally Observed Reverse Intersystem Crossing-Boosted Lasing.

Thermally activated delayed-fluorescent (TADF) materials are anticipated to overcome triplet-related losses towards electrically driven organic lasers. Thus far, contributions from triplets to lasing have not yet been experimentally demonstrated owing to the limited knowledge about the excited-state processes. Herein, we experimentally achieve reverse intersystem crossing (RISC)-boosted lasing in organic microspheres with uniformly dispersed TADF emitters. In these materials, triplets are continuously converted to radiative singlets through RISC, giving rise to reduced losses in stimulated emission. The involvement of regenerated singlets in population inversion results in a thermally activated lasing; that is, the lasing intensity increases with increasing temperature, accompanied by accelerated depletion of the excited-state population. Benefiting from the suppression of triplet accumulations by RISC processes, a high-repetition-rate microlaser was achieved.

Switchable Single-Mode Perovskite Microlasers Modulated by Responsive Organic Microdisks.

Miniaturized lasers with high spectra purity and switchable output are of crucial importance for various ultracompact photonic devices. However, it still remains a great challenge to simultaneously control the wavelength and mode purity of microscale lasers due to the insensitive response of traditional materials to external stimuli. In this work, we propose a strategy to realize switchable single-mode microlasers in perovskite microwires (MWs) coupled with responsive organic microdisk cavities. The perovskite MW therein serves as an excellent laser source to deliver multiple lasing modes, while the microdisk functions as a spectral filter to achieve single-mode outcoupling. Furthermore, on account of the sensitive responsiveness of organic materials, reversible wavelength-switching of single-mode laser can be realized through adjusting the resonant modes of the microdisk cavity filter. The results will provide guidance for the rational design of nanophotonic devices with novel performances based on the characteristic of organic materials.

Stimulated Emission-Controlled Photonic Transistor on a Single Organic Triblock Nanowire.

In this work, we demonstrate a stimulated emission-controlled photonic transistor on a single organic triblock nanowire composed of alternate energy donor and acceptor. The population of acceptor excitons was engineered by energy transfer to achieve enhanced fluorescence, which was further amplified by the stimulated emission of the donor and the optical feedback in the nanowire microcavities, yielding a remarkable nonlinear amplification of the acceptor emission. On this basis, a prototype of photonic transistor with high nonlinear gain at very low pump energy was achieved. The results will provide a useful enlightenment for the rational design of novel all-optical switches with desired performances.

Wavelength Division Multiplexer Based on Semiconductor Heterostructures Constructed via Nanoarchitectonics.

Obtaining a wavelength division multiplexer (WDM) at the micro/nanometer level is a considerable challenge that holds great potential in optical communication technology owing to the enlarged data-carrying capacity without laying more fibers. Of the progress that has been made in recent years, one of the most promising methods is to fabricate nanoscale pattern on silicon substrate, forcing signals of different wavelength to enter predesigned channels due to the alternant changes in refractive index. However, it is not an easy task to incorporate light sources into these WDM systems, because of the nonradiative characteristics of silicon itself. This study demonstrates a successful integration of laser signal sources and WDM fully with 1D semiconductor structures. Nanowires from II-VI semiconductor serve as both lasing media and low-loss waveguides for signal loading and delivering, respectively. On the basis of the distinct size-dependent cut-off effect, finely tuning the diameters of homojunctions would result in a controllable filtering of confined signal that light, beyond cut-off wavelength, cannot transfer within the narrowed segments any longer. These results pave the way for semiconductor photonic components toward integration.

Strong Photonic-Band-Gap Effect on the Spontaneous Emission in 3D Lead Halide Perovskite Photonic Crystals.

Stimulated emission in perovskite-embedded polymer opal structures is investigated. A polymer opal structure is filled with a perovskite, and perovskite photonic crystals are prepared. The spontaneous emission of the perovskite embedded in the polymer opal structures exhibits clear signatures of amplified spontaneous emission (ASE) via gain modulation. The difference in refractive-index contrast between the perovskite and the polymer opal is large enough for retaining photonic-crystals properties. The photonic band gap has a strong effect on the fluorescence emission intensity and lifetime. The stimulated emission spectrum exhibits a narrow ASE rather than a wide fluorescence peak in the thin film.

Organic Microcrystal Vibronic Lasers with Full-Spectrum Tunable Output beyond the Franck-Condon Principle.

The very broad emission bands of organic semiconductor materials are, in theory, suitable for achieving versatile solid-state lasers; however, most of organic materials only lase at short wavelength corresponding to the 0-1 transition governed by the Franck-Condon (FC) principle. A strategy is developed to overcome the limit of FC principle for tailoring the output of microlasers over a wide range based on the controlled vibronic emission of organic materials at microcrystal state. For the first time, the output wavelength of organic lasers is tailored across all vibronic (0-1, 0-2, 0-3, and even 0-4) bands spanning the entire emission spectrum.

All-Color Subwavelength Output of Organic Flexible Microlasers.

All-color subwavelength output of lasers was demonstrated in a rationally designed organic microdisk/silver nanowire heterostructures. The dye-doped flexible microdisks served as the wavelength tunable whispering-gallery-mode lasers with low lasing thresholds, whereas the silver nanowires supported the output of the lasing mode as subwavelength coherent light sources. The wavelength of the outcoupled laser was tuned over the full visible spectrum scope owing to the flexibility of the microdisks and their compatibility with various organic laser dyes. Furthermore, a multicolor subwavelength laser was achieved in a single heterostructure and the laser output was successfully modulated by varying the surface plasmon polariton propagation length.