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Understanding interactions between molecular transition and intense electromagnetic fields confined by plasmon nanostructures is of great significance due to their huge potential in fundamental cavity quantum electrodynamics and practical applications. Here, we report reorientable plasmon-enhanced fluorescence leveraging the flexibilities in densely-packed gold nanogap arrays by template-assisted depositions. By finely adjusting the symmetry of the unit structure, arrays of nanogaps along two nearly-orthogonal axes can be tailored collectively with spacing down to sub-10 nm on a single chip, facilitating distinct "inter-cell" and "intra-cell" plasmon couplings. Through engineering two sets of nanogaps, the varying hybridization-induced plasmonic bonding modes lead to adjustable splitting of the fluorescence emission peak with a width up to 81 nm and narrowing of linewidths up to a factor of 3. Besides, polarization anisotropy with a ratio up to 63% is obtained on the basis of spectrally separated local hotspots with discrepant oscillation directions. The developed plasmonic nanogap array is envisaged to provide a promising chip-scale, cost-effective platform for advancing fluorescence-based detection and emission technologies in both classical and quantum regimes.

We report the monolithic fabrication of twin microtube cavities by a nanomembrane origami method for achieving collective coupling of 3D confined optical modes. Owing to the well-aligned twin geometries, two sets of 3D confined optical modes in twin microtubes are spectrally and spatially matched, by which both the fundamental and higher-order axial modes are respectively coupled with each other. Multiple groups of the coupling modes provide multiple effective channels for energy exchange between coupled microcavities illustrated by the measured spatial optical field distributions. The spectral anticrossing and changing-over features of each group of coupled modes are revealed in experiments and calculations, indicating the occurrence of strong coupling. In addition, the simulated 3D mode profiles of twin microcavities confirm the collective strong coupling behavior, which shows good agreement with experiments. The collective coupling of 3D confined resonant modes promises broad applications in multichannel optical signal processing, nanophotonics, and 3D non-Hermitian systems.

Understanding the diffusion of small molecules in polymer microsystems is of great interest in diverse fundamental and industrial research. Despite the rapidly advancing optical imaging and spectroscopic techniques, entities under investigation are usually limited to flat films or bulky samples. We demonstrate a route to in situ detection of diffusion dynamics in polymer micro-objects by means of optical whispering-gallery mode resonances. Through mode tracking, interactions between solvent molecules and polymer microspheres, including sorption, diffusion, and swelling can be quantitatively analyzed. A turning point of mode response is observed, while the diffusion exceeds the sub-wavelength-thick outermost layer as the radial extent of resonances and starts penetrating the inner core. The estimated solubility in the glassy polymer is consistent with the predicted value using Flory-Huggins theory. Besides, the non-Fickian contribution is analyzed in such a glassy polymer-penetrant system. Our work represents a high-precision and label-free approach to describing characteristics in diffusion dynamics.

The large library of organic dye molecules offers almost infinite possibilities for laser design, but still faces a great challenge in achieving pure dye aggregate lasers due to intermolecular quenching. Here, we report a kinetically controlled molecular self-assembly strategy to synthesize unconventional dye microcrystals for lasing. By increasing temperature, the dye self-assembly is transformed from thermodynamic to kinetic control. Unlike the thermodynamic microcrystal products incapable of lasing due to intermolecular charge-transfer-mediated excimer formation, the kinetic dye microcrystals have large intermolecular distances and weak intermolecular interactions, supporting highly efficient intramolecular charge-transfer monomer emission and low-threshold lasing. This work demonstrates single-crystal dye lasers, promising to unleash the full potential of laser dyes in solid-state lasers.

We report the generation of multiple sets of 3D confined resonant modes in a single microtube cavity owing to nanogap induced resonant trajectory splits. The optical field largely overlaps in the split resonant trajectories, enabling strong optical coupling of 3D confined resonant light. The anticrossing feature and modes changing-over were demonstrated as direct evidence of strong coupling. In such an optical coupling system, the spatial optical field distribution of 3D coupling modes was experimentally mapped under the strong coupling regime, which allows direct observation of the energy transfer process between two hybrid states. Numerical calculations based on a quasi-potential model and the mode detuning process are in excellent agreement with the experimental results. The generation of multiple sets of 3D confined resonant modes and their efficient coupling in a single microcavity are of high interest for directional coupling with a higher degree of freedom to realize on-chip integration with elevated functionalities such as multiplexing, 3D lasing, and signal processing.

Manipulating photons in artificially structured materials is highly desired in modern photonic technology. Nontrivial topological structures are rapidly emerging as a state-of-art platform for achieving unprecedented fascinating phenomena of photon manipulation. However, the current studies mainly focus on planar structures, and the fabrication of photonic microstructures with specific topological geometric features still remains a great challenge. Extending the topological photonics to 3D microarchitectures is expected to enrich the photon manipulation capabilities and further advance the topological photonic devices. Here, a femtosecond laser direct writing technique is employed to fabricate 3D topological Möbius microring resonators from dye-doped polymer. The high-quality-factor Möbius microring resonator supports a unique spin-orbit coupled lasing at very low threshold. Due to the spin-orbit coupling induced geometric/Berry phase, the Möbius microrings, in striking contrast with ordinary microrings, output laser signals with all polarization states. The manipulation of miniaturized coherent light sources in the fabricated Möbius microrings represents a significant step forward toward 3D topological photonics that offers a novel design philosophy for functional photonic and optoelectronic devices.

Switchable multimode microlasers are of great significance to the development of photonic devices with high integration levels. Herein, we demonstrate an acid/alkaline gas-responsive multimode AIEgen@starch microsphere-based microlaser. The aggregation-induced emission (AIE) active fluorescent dye ASCPI was used as the gain medium in this study. ASCPI was weakly emissive in water but became highly emissive when introduced to a starch microsphere as a guest molecule. The resultant ASCPI@starch microsphere worked well as a typical whispering-gallery-mode microlaser. The laser mode wavelengths were size-dependent. Due to the sensitivity of ASCPI to pH, the output of the microlaser could be switched to a shorter wavelength by acetic acid vapor treatment or a longer wavelength by NH3 vapor treatment. This work will provide useful enlightenment for the rational design of effective switchable lasers using AIE materials with simple preparation procedures.

Efficient radiative recombination is essential for perovskite luminescence, but the intrinsic radiative recombination rate as a basic material property is challenging to tailor. Here we report an interfacial chemistry strategy to dramatically increase the radiative recombination rate of perovskites. By coating aluminum oxide on the lead halide perovskite, lead-oxygen bonds are formed at the perovskite-oxide interface, producing the perovskite surface states with a large exciton binding energy and a high localized density of electronic state. The oxide-bonded perovskite exhibits a ≈500 fold enhanced photoluminescence with a ≈10 fold reduced lifetime, indicating an unprecedented ≈5000 fold increase in the radiative recombination rate. The enormously enhanced radiative recombination promises to significantly promote the perovskite optoelectronic performance.

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.

Sluggish conversion reactions severely impair the rate capability for lithium storage, which is the main disadvantage of the conversion-type anode materials. Here, the microplatform based on a sing...

Background The purpose of the study is to describe the blood lipid levels of patients diagnosed with coronavirus disease 2019 (COVID-19) and to analyze the correlation between blood lipid levels and the prognosis of COVID-19 patients. Methods In the clinical retrospective analysis, a total of 228 adults infected with COVID-19 were enrolled between January 17, 2020 and March 14, 2020, in Changsha, China. One thousand one hundred and forty healthy participants with matched age and gender were used as control. Median with interquartile range and Mann-Whitney test were adopted to describe and analyze clinical data. The Kaplan-Meier (KM) curve and Cox regression analysis were used to analyze the correlation between high-density lipoprotein cholesterol (HDL-C) and the severity of COVID-19. Results Compared with control, COVID-19 patients showed significantly lower levels of total cholesterol (TC) [median, 3.76 vs 4.65 mmol/L, P = 0.031], triglyceride [median, 1.08 vs 1.21 mmol/L, P P P P = 0.032]. In comparison with patients with high HDL-C, patients with low HDL-C showed a higher proportion of male (69.57% vs 45.60%, P = 0.004), higher levels of C-reactive protein (CRP) (median, 27.83 vs 12.56 mg/L, P P = 0.001). Moreover, patients with low HDL-C at admission showed a higher risk of developing severe events compared with those with high HDL-C (Log Rank P = 0.009). After adjusting for age, gender and underlying diseases, they still had elevated possibility of developing severe cases than those with high HDL-C (HR 2.827, 95% CI 1.190–6.714, P = 0.019). Conclusions HDL-C level was lower in COVID-19 adult patients, and low HDL-C in COVID-19 patients was correlated with a higher risk of developing severe events.

Miniaturized lasers with high spectral purity and wide wavelength tunability are crucial for various photonic applications. Here we propose a strategy to realize broadband-tunable single-mode lasing based on a photoisomerization-activated intramolecular charge-transfer (ICT) process in coupled polymer microdisk cavities. The photoisomerizable molecules doped in the polymer microdisks can be quantitatively transformed into a kind of laser dye with strong ICT character by photoexcitation. The gain region was tailored over a wide range through the self-modulation of the optically activated ICT isomers. Meanwhile, the resonant modes shifted with the photoisomerization because of a change in the effective refractive index of the polymer microdisk cavity. Based on the synergetic modulation of the optical gain and microcavity, we realized the broadband tuning of the single-mode laser. These results offer a promising route to fabricate broadband-tunable microlasers towards practical photonic integrations.

Metal-organic frameworks (MOFs) are an emerging kind of laser material, yet they remain a challenge in the controlled fabrication of crystal nanostructures with desired morphology for tuning their optical microcavities. Herein, the shape-engineering of pure MOF microlasers was demonstrated based on the coordination-mode-tailored method. The one-dimensional (1D) microwires and 2D microplates were selectively fabricated through changing the HCl concentration to tailor the coordination modes. Both the single-crystalline microwires and microplates with strong optical confinement functioned as low-threshold MOF microlasers. Moreover, distinct lasing behaviors of 1D and 2D MOF microcrystals confirm a typical shape-dependent microcavity effect: 1D microwires serve as Fabry-Pérot (FP) resonators, and 2D microplates lead to the whispering-gallery-mode (WGM) microcavities. These results provide a special pathway for the exploitation of MOF-based micro/nanolasers with on-demand functions.

The invention and development of the laser have revolutionized science, technology, and industry. Metal halide perovskites are an emerging class of semiconductors holding promising potential in further advancing the laser technology. In this Review, we provide a comprehensive overview of metal halide perovskite lasers from the viewpoint of materials chemistry and engineering. After an introduction to the materials chemistry and physics of metal halide perovskites, we present diverse optical cavities for perovskite lasers. We then comprehensively discuss various perovskite lasers with particular functionalities, including tunable lasers, multicolor lasers, continuous-wave lasers, single-mode lasers, subwavelength lasers, random lasers, polariton lasers, and laser arrays. Following this a description of the strategies for improving the stability and reducing the toxicity of metal halide perovskite lasers is provided. Finally, future research directions and challenges toward practical technology applications of perovskite lasers are provided to give an outlook on this emerging field.

The combination of plasmonic nanoparticles and optical microcavities has attracted broad interest for both fundamental and applied studies. However, the conventional scheme of plasmonic nanoparticles being located at microcavity outer surfaces suffers from serious problems such as significant radiative/scattering losses and chemical/mechanical instabilities. Here, silver nanoparticles (NPs) and dispersed ions embedded in nanomembrane-formed whispering-gallery-mode (WGM) microtube cavities are prepared by ion implantations as compact and stable optoplasmonic microcavities. Upon low ion fluence implantation, dispersed silver ions are generated in the tube cavity wall, leading to a redshift of the WGM resonant cavity modes due to the increased refractive index. The silver ions start to aggregate into plasmonic NPs in the cavity wall when increasing implantation ion fluences. The competition and transition between redshift induced by the refractive index increase and blueshift induced by the formation of plasmonic NPs are investigated. Moreover, quality factor enhancement of the WGM modes is observed owing to the improved light confinement caused by the presence of NPs. This work demonstrates a convenient approach for the fabrication of stable optoplasmonic microcavities and fine tuning of resonant modes, indicating wide applications such as wavelength selective tuning and enhanced light–matter interactions.

Control over material architectures is essential to the performance of photonic devices and systems. Optical isolation of the photonic materials from substrates can significantly enhance their performance but suffers from complicated fabrication processes and limited applications. Here a differential polymer chain scission strategy is proposed to fabricate free-standing photonic structures based on one-step electron-beam direct writing on polymer bilayers (EOB). The polymer molecular mass-dependent sensitivity to electron beam enables differential patterning of the two layers of polymers, leading to the direct formation of suspended optical microcavities. The EOB technique features high materials compatibility and design flexibility for the optical microcavities, which significantly expands the application scope of the suspended optical microcavities. As well as providing a versatile strategy for building high-performance photonic materials, the results provide a promising platform for innovative applications of optical microstructures.

Organic composite materials have been attracting extensive research interest for light‐emitting applications. A wide variety of luminescent organic composite materials have been synthesized, which are of great significance for both the investigation of basic photophysics and the realization of high‐performance photonic devices. Function‐oriented syntheses of luminescent organic composite materials rely on the understanding and manipulating of molecular excited states. In this review, we focus on the discussion about the structure design and dynamics modulation of the electronic excited states in the organic composite materials. The excited‐state structures and dynamics involve singlet/triplet levels, vibronic transition, charge transfer, and energy transfer, and so on, while the light‐emitting behaviors include fluorescence, phosphorescence, persistent luminescence, electroluminescence, and lasing. We aim to give insight into the relationship between light‐emitting properties and excited states of organic composite materials, which is beneficial for reaching higher tiers of design and applications of luminescent organic composite materials.

The current Coronavirus disease 2019 (COVID-19) pandemic has become a global challenge. Managing a large number of acutely ill patients in a short time, whilst reducing the fatality rate and dealing with complications, brings unique difficulties. The most striking pathophysiological features of patients with severe COVID-19 are dysregulated immune responses and abnormal coagulation function, which can result in multiple-organ failure and death. Normally metabolized high-density lipoprotein (HDL) performs several functions, including reverse cholesterol transport, direct binding to lipopolysaccharide (LPS) to neutralize LPS activity, regulation of inflammatory response, anti-thrombotic effects, antioxidant, and anti-apoptotic properties. Clinical data shows that significantly decreased HDL levels in patients with COVID-19 are correlated with both disease severity and mortality. However, the role of HDL in COVID-19 and its specific mechanism remain unclear. In this analysis, we review current evidence mainly in the following areas: firstly, the pathophysiological characteristics of COVID-19, secondly, the pleiotropic properties of HDL, thirdly, the changes and clinical significance of HDL in COVID-19, and fourthly the prospect of HDL-targeting therapy in COVID-19 to clarify the role of HDL in the pathogenesis of COVID-19 and discuss the potential of HDL therapy in COVID-19.

Imperceptible electronics will make next-generation healthcare and biomedical systems thinner, lighter, and more flexible. While other components are thoroughly investigated, imperceptible energy storage devices lag behind because the decrease of thickness impairs the area-specific energy density. Imperceptible supercapacitors with high area-specific capacitance based on reduced graphene oxide/polyaniline (RGO/PANI) composite electrodes and polyvinyl alcohol (PVA)/H2 SO4 gel electrolyte are reported. Two strategies to realize a supercapacitor with a total device thickness of 5 µm-including substrate, electrode, and electrolyte-and an area-specific capacitance of 36 mF cm-2 simultaneously are implemented. First, the void volume of the RGO/PANI electrodes through mechanical compression is reduced, which decreases the thickness by 83% while retaining 89% of the capacitance. Second, the PVA-to-H2 SO4 mass ratio is decreased to 1:4.5, which improves the ion conductivity by 5000% compared to the commonly used PVA/H2 SO4 gel. Both advantages enable a 2 µm-thick gel electrolyte for planar interdigital supercapacitors. The impressive electromechanical stability of the imperceptible supercapacitors by wrinkling the substrate to produce folds with radii of 6 µm or less is demonstrated. The supercapacitors will be meaningful energy storage modules for future self-powered imperceptible electronics.

Synthesis of novel mesoscopic semiconductor architectures continually generates new photonic knowledge and applications. However, it remains a great challenge to synthesize semiconductor microcrystals with smoothly curved surfaces owing to the crystal growth anisotropy. Here, a superkinetic crystal growth method is developed to synthesize 2D oval organic semiconductor microcrystals. The solid source dispersion induces an exceptionally large molecular supersaturation for vapor deposition, which breaks the crystal growth anisotropy. The synthesized stadium-shaped organic semiconductor microcrystals naturally constitute fully chaotic optical microresonators. They support low-threshold lasing on high-quality-factor scar modes localized near the stadium boundary and directional laser emission assisted by the chaotic modes. These results will reshape the understanding of the crystal growth theory and provide valuable guidance for crystalline photonic materials design.

Background and Purpose. Allergic asthma, a respiratory disease with high morbidity and mortality, is reported to be related to the airway allergic inflammation and autophagy-induced oxidative stress. Although the therapeutic effects of fermentate prebiotic (YFP) on allergic asthma have been widely claimed, the underlying mechanism is still unclear. This study is aimed at investigating the possible mechanism for the antiasthma property of YFP in a mouse model. Methods. Ovalbumin was used to induce allergic asthma following administration of YFP for one week in mice, to collect the lung tissues, bronchoalveolar lavage fluid (BLFA), and feces. The pathological state, tight-junction proteins, inflammatory and oxidative stress-associated biomarkers, and TLRs/NF-κB signaling pathway of the lung tissues were evaluated by HE staining, immunofluorescence, ELISA, and WB, separately. RT-PCR was used to test oxidative stress-associated genes. Leukocyte counts of BLFA and intestinal microbiota were also analyzed using a hemocytometer and 16S rDNA-sequencing, separately. Result. YFP ameliorated the lung injury of the mouse asthma model by inhibiting peribronchial and perivascular infiltrations of eosinophils and increasing tight-junction protein expression. YFP inhibited the decrease in the number of BALF leukocytes and expression of inflammatory-related genes and reversed OVA-induced TLRs/NF-κB signaling pathway activation. YFP ameliorated the level of oxidative stress in the lung of the mouse asthma model by inhibiting MDA and promoting the protein level of GSH-PX, SOD, CAT, and oxidative-related genes. ATG5, Beclin1, and LC3BII/I were significantly upregulated in asthma mice, which were greatly suppressed by the introduction of YFP, indicating that YFP ameliorated the autophagy in the lung of the mouse asthma model. Lastly, the distribution of bacterial species was slightly changed by YFP in asthma mice, with a significant difference in the relative abundance of 6 major bacterial species between the asthma and YFP groups. Conclusion. Our research showed that YFP might exert antiasthmatic effects by inhibiting airway allergic inflammation and oxidative stress level through suppressing autophagy.

Owing to their high safety and reversibility, aqueous microbatteries using zinc anodes and an acid electrolyte have emerged as promising candidates for wearable electronics. However, a critical limitation that prevents implementing zinc chemistry at the microscale lies in its spontaneous corrosion in an acidic electrolyte that causes a capacity loss of 40% after a ten-hour rest. Widespread anti-corrosion techniques, such as polymer coating, often retard the kinetics of zinc plating/stripping and lack spatial control at the microscale. Here, a polyimide coating that resolves this dilemma is reported. The coating prevents corrosion and hence reduces the capacity loss of a standby microbattery to 10%. The coordination of carbonyl oxygen in the polyimide with zinc ions builds up over cycling, creating a zinc blanket that minimizes the concentration gradient through the electrode/electrolyte interface and thus allows for fast kinetics and low plating/stripping overpotential. The polyimide's patternable feature energizes microbatteries in both aqueous and hydrogel electrolytes, delivering a supercapacitor-level rate performance and 400 stable cycles in the hydrogel electrolyte. Moreover, the microbattery is able to be attached to human skin and offers strong resistance to deformations, splashing, and external shock. The skin-mountable microbattery demonstrates an excellent combination of anti-corrosion, reversibility, and durability in wearables.

Background: Coronavirus disease 2019 (COVID-19) has been shown to affect almost every organ throughout the body. However, it is not clear whether the thyroid gland is impaired in COVID-19 patients. Euthyroid sick syndrome (ESS) is usually associated with the disease severity and deterioration prognosis in critical illness. In this study, the thyroid function of COVID-19 patients was assessed and factors associated with outcomes were analyzed to determine the potential predictive value of ESS. Methods: Clinical and laboratory data of COVID-19 patients with or without ESS in Changsha, China, were collected and analyzed on admission. Kaplan-Meier curve and cox regression model were utilized to determine the correlation between ESS and the endpoints. Subsequently, a receiver operating characteristic (ROC) curve was plotted to evaluate the predictive performances of FT3 and C-reactive protein (CRP) in the disease severity. Results: Forty-one (27.52%) cases of COVID-19 patients diagnosed with ESS. ESS patients had higher proportions of fever, shortness of breath, hypertension, diabetes, and severe events than those of non-ESS patients. The levels of erythrocyte sedimentation rate and C-reactive protein, and the positive rate of procalcitonin were significantly higher, whereas the lymphocyte count was apparently lower in ESS patients than in non-ESS patients. The regression analysis showed that ESS was significantly associated with the disease severity of COVID-19 (HR = 2.515, 95% CI: 1.050-6.026, P = 0.039). The areas under the curve (AUCs) for predicting the severe disease were [0.809 (95% CI 0.727-0.892), P < 0.001] and [0.792 (95% CI 0.689-0.895), P < 0.001] for FT3 and CRP, respectively. Conclusion: ESS was significantly associated with the disease severity and inflammatory parameters in COVID-19 patients.