Direct growth Bi2O2Se nanosheets on SiO2/Si substrate for high-performance and broadband photodetector.

Bi2O2Se, a newly emerging two-dimensional (2D) material, has attracted significant attention as a promising candidate for optoelectronics applications due to its exceptional air stability and high mobility. Generally, mica and SrTiO3substrates with lattice matching are commonly used for the growth of high-quality 2D Bi2O2Se. Although 2D Bi2O2Se grown on these insulating substrates can be transferred onto Si substrate to ensure compatibility with silicon-based semiconductor processes, this inevitably introduces defects and surface states that significantly compromise the performance of optoelectronic devices. Herein we employ Bi2Se3as the evaporation source and oxygen reaction to directly grow Bi2O2Se nanosheets on Si substrate through a conventional chemical vapor deposition method. The photodetector based on the Bi2O2Se nanosheets on Si substrate demonstrates outstanding optoelectronics performance with a responsivity of 379 A W-1, detectivity of 2.9 × 1010Jones, and rapid response time of 0.28 ms, respectively, with 532 nm illumination. Moreover, it also exhibits a broadband photodetection capability across the visible to near-infrared range (532-1300 nm). These results suggest that the promising potential of Bi2O2Se nanosheets for high-performance and broadband photodetector applications.

Plasmonic Polarization Rotation in SERS Spectroscopy.

Surface-enhanced Raman optical activity (SEROA) has been extensively investigated due to its ability to directly probe stereochemistry and molecular structure. However, most works have focused on the Raman optical activity (ROA) effect arising from the chirality of the molecules on isotropic surfaces. Here, we propose a strategy for achieving a similar effect: i.e., a surface-enhanced Raman polarization rotation effect arising from the coupling of optically inactive molecules with the chiral plasmonic response of metasurfaces. This effect is due to the optically active response of metallic nanostructures and their interaction with molecules, which could extend the ROA potential to inactive molecules and be used to enhance the sensibility performances of surface-enhanced Raman spectroscopy. More importantly, this technique does not suffer from the heating issue present in traditional plasmonic-enhanced ROA techniques, as it does not rely on the chirality of the molecules.

Discovery of imidazo[1,2-b]pyridazine macrocyclic derivatives as novel ALK inhibitors capable of combating multiple resistant mutants.

Anaplastic lymphoma kinase (ALK)-tyrosine kinase inhibitor (TKI) often loses effectiveness against non-small cell lung malignancies (NSCLCs) with ALK gene rearrangements (ALK+). 19 novel imidazo[1,2-b]pyridazine macrocyclic derivatives were designed, synthesized, and tested for their biological activities in an effort to develop ALK inhibitors that would overcome second-generation ALK-TKIs, particularly the G1202R mutation and the lorlatinib-resistant L1196M/G1202R double mutations. Of all the target substances, O-10 had the most effective enzymatic inhibitory activity, with IC50 values for ALKWT, ALKG1202R, and ALKL1196M/G1202R of 2.6, 6.4, and 23 nM, respectively. O-10, on the other hand, reduced the growth of ALK-positive Karpas299, BaF3-EML4-ALKG1202R, and BaF3-EML4-ALKL1196M/G1202R cells with IC50 values of 38, 52, and 64 nM, respectively. This was equally effective to the reference drug Repotrectinib (IC50 = 40, 164, and 208 nM). The kinase selectivity profile, liver microsome stability test and in vivo pharmacokinetic properties in SD rats of compound O-10 were further evaluated. O-10 was regarded as an effective ALK inhibitor for the treatment of mutations overall.

Design, synthesis and biological evaluation of novel macrocyclic derivatives bearing aniline pyrimidine scaffolds as EGFR-TKIs.

Based on EGFR-TKI Osimertinib as lead compound, a series of novel macrocyclic derivatives bearing aniline pyrimidine scaffolds were designed and synthesized by macrocyclization. Their structures were identified by 1H NMR, 13C NMR, 19F NMR and HRMS. The pharmacological activities of the target compounds were tested and the preliminary structure-activity relationship was discussed. Among them, 17-membered ring compound H1 displayed the best inhibitory activities against EGFRL858R/T790M and EGFRd746-750/T790M with IC50 value of 2.92 nM and 0.34 nM, respectively. Exhilaratingly, 17-membered ring compound H7 possessed the most potent antiproliferative activity against BaF3-EGFRdel19/T790M cell lines (IC50 = 0.035 µm), which rivaled that of Osimertinib (IC50 = 0.033 µm).

Multiplexing-oriented plasmon-MoS2 hybrid metasurfaces driven by nonlinear quasi bound states in the continuum.

Rapid progress in nonlinear plasmonic metasurfaces enabled many novel optical characteristics for metasurfaces, with potential applications in frequency metrology [Zimmermann et al. Opt. Lett. 29:310 (2004)], timing characterization [Singh et al. Laser Photonics Rev. 14:1 (2020)] and quantum information [Kues et al. Nature. 546:622 (2017)]. However, the spectrum of nonlinear optical response was typically determined from the linear optical resonance. In this work, a wavelength-multiplexed nonlinear plasmon-MoS2 hybrid metasurface with suppression phenomenon was proposed, where multiple nonlinear signals could to be simultaneously processed and optionally tuned. A clear physical picture to depict the nonlinear plasmonic bound states in the continuum (BICs) was presented, from the perspective of both classical and quantum approaches. Particularly, beyond the ordinary plasmon-polariton effect, we numerically demonstrated a giant BIC-inspired second-order nonlinear susceptibility 10-5m/V of MoS2 in the infrared band. The novelty in our study lies in the presence of a quantum oscillator that can be adopted to both suppress and enhance the nonlinear quasi BICs. This selectable nonlinear BIC-based suppression and enhancement effect can optionally block undesired modes, resulting in narrower linewidth as well as smaller quantum decay rates, which is also promising in slow-light-associated technologies.

Giant polarization anisotropic optical response from anodic aluminum oxide templates embedded with plasmonic metamaterials.

Plasmonic metamaterials enable extraordinary manipulation of key constitutive properties of light at a subwavelength scale and thus have attracted significant interest. Here, we report a simple and convenient nanofabrication method for a novel meta-device by glancing deposition of gold into anodic aluminum oxide templates on glass substrates. A methodology with the assistance of ellipsometric measurements to examine the anisotropy and optical activity properties is presented. A tunable polarization conversion in both transmission and reflection is demonstrated. Specifically, giant broadband circular dichroism for reflection at visible wavelengths is experimentally realized by oblique incidence, due to the extrinsic chirality resulting from the mutual orientation of the metamaterials and the incident beam. This work paves the way for practical applications for large-area, low-cost polarization modulators, polarization imaging, displays, and bio-sensing.

Sensitive and Reproducible Immunoassay of Multiple Mycotoxins Using Surface-Enhanced Raman Scattering Mapping on 3D Plasmonic Nanopillar Arrays.

A surface-enhanced Raman scattering-based mapping technique is reported for the highly sensitive and reproducible analysis of multiple mycotoxins. Raman images of three mycotoxins, ochratoxin A (OTA), fumonisin B (FUMB), and aflatoxin B1 (AFB1) are obtained by rapidly scanning the surface-enhanced Raman scattering (SERS) nanotags-anchoring mycotoxins captured on a nanopillar plasmonic substrate. In this system, the decreased gap distance between nanopillars by their leaning effects as well as the multiple hot spots between SERS nanotags and nanopillars greatly enhances the coupling of local plasmonic fields. This strong enhancement effect makes it possible to perform a highly sensitive detection of multiple mycotoxins. In addition, the high uniformity of the densely packed nanopillar substrate minimizes the spot-to-spot fluctuations of the Raman peak intensity in the scanned area when Raman mapping is performed. Consequently, this makes it possible to gain a highly reproducible quantitative analysis of mycotoxins. The limit of detections (LODs) are determined to be 5.09, 5.11, and 6.07 pg mL-1 for OTA, FUMB, and AFB1, and these values are approximately two orders of magnitude more sensitive than those determined by the enzyme-linked immunosorbent assays. It is believed that this SERS-based mapping technique provides a facile tool for the sensitive and reproducible quantification of various biotarget molecules.

Wrinkled stripes localized by cracks in metal films deposited on soft substrates.

Homogeneous global wrinkling patterns such as labyrinths, herringbones, ripples and straight stripes can be widely observed in natural and artificial systems, but localized wrinkling patterns (not including buckle-driven delaminations, folds, ridges and creases) are seldom observed in experiments. Here we report on the spontaneous formation of highly ordered wrinkled stripes localized by cracks in metal films deposited on soft substrates. The experiment shows that the metal film is under a large tensile stress during deposition, which is relieved by the formation of networked cracks. After deposition, a compressive stress is stored up in the film and it always focuses near the new formed cracks due to the plastic deformation of the film, resulting in the formation of localized wrinkled stripes composed of a large number of straight wrinkles perpendicular to the cracks. The morphological characteristic, formation mechanism and evolution behaviors of the localized wrinkled stripes have been described and discussed in detail.

Dual-wavelength extinction method for fast sizing of metal nanosphere ensembles.

We propose a simple dual-wavelength extinction (DWE) method to measure the average size of spherical metal nanoparticle (NP) ensembles. Unlike the spectroscopic methods that need to measure the full spectra of scattering and/or extinction to retrieve the NP size, the DWE method can estimate the NP size by measuring the light extinction at only two properly selected wavelengths and thus is useful for fast sizing of metal NP ensembles. The influences of the NP shape deviation and ensemble dispersancy on the measurement accuracy are analyzed and discussed in detail. An empirical correction procedure is established to compensate these influences to further improve accuracy. The feasibility and reliability of the DWE method are corroborated by experimentally measuring several typical gold spherical NP ensembles and comparing the results with those obtained by three other standard methods. The experimental results indicate satisfactory accuracy of the DWE method for measuring gold NPs from 30 to 100 nm by using two measurement wavelengths of 532 and 573 nm. The studies show that the DWE method is efficient, reliable, and easy to implement. It may find wide applications in the metrology of NPs.

Fast decomposed method to devise broadband polarization-conversion metasurface.

Designing a broadband, wide-angle, and high-efficient polarization converter with a simple geometry remains challenging. This work proposes a simple and computationally inexpensive method for devising broadband polarization conversion metasurfaces. We focus on a cross-shape configuration consisting of two bars of different lengths connected at the center. To design the metasurface, we decompose the system into two parts with two orthogonally polarized responses and calculate the response of each part separately. By selecting the parameters with a proper phase difference in the response between the two parts, we can determine the dimensions of the system. For designing broadband polarization conversion metasurfaces, we define a fitness function to optimize the bandwidth of the linear polarization conversion. Numerical results demonstrate that the proposed method can be used to design a metasurface that achieves a relative bandwidth of [Formula: see text] for converting linearly polarized waves into cross-polarized waves. Additionally, the average polarization conversion ratio of the designed metasurface is greater than [Formula: see text] over the frequency range of 10.9-28.5 GHz. This method significantly reduces the computational expense compared to the traditional method and can be easily extended to other complex structures and configurations.

Carbon Nanotube Transistor with Colloidal Quantum Dot Photosensitive Gate for Ultrahigh External Quantum Efficiency Photodetector.

PbS colloidal quantum dots (CQDs) are promising building block for developing the next-generation high-performance near-infrared (NIR) photodetector. However, due to the surface ligand isolation and surface defects, PbS CQDs usually suffer from low carrier mobility, which limits further optimization of PbS CQDs-based optoelectronic devices. Here, the combination of PbS CQD photodiode and carbon nanotube (CNT) film field-effect transistor (FET) achieves a transistorized NIR photodetector with a photosensitive gate. The photogenerated electrons are drifted to the dielectric surface by a negative gate electric field and built-in electric field, serving as an equivalent gate voltage to turn on the CNT FET, thus realizing the conversion of optical signals to electrical signals. The photodetector exhibits high performance, with a responsivity and detectivity of 41.9 A/W and 3.04 × 1011 Jones under 950 nm illumination, respectively. More importantly, the photodetector achieves an ultrahigh external quantum efficiency (EQE) of 5470% due to the CNT FET amplification function. Besides, the photodetector demonstrates a versatile photoresponse that allows for regulation of responsivity, detectivity, and EQE over a wide range through gate voltage control. The photodetector shows immense potential in NIR photodetection applications, and the distinctive structure of the optical module and electrical module separation also provides fresh thinking for the research and development of the next generation of optoelectronic devices.

Crystalline AuNP-Decorated Strontium Niobate Thin Films: Strain-Controlled AuNP Morphologies and Optical Properties for Plasmonic Applications.

Gold nanoparticle (AuNP) decoration is a commonly used method to enhance the optical responses in many applications such as photocatalysis, biosensing, solar cells, etc. The morphology and structure of AuNPs are essential factors determining the functionality of the sample. However, tailoring the growth mechanism of AuNPs on an identical surface is not straightforward. In this study, AuNPs were deposited on the surface of a perovskite thin film, strontium niobate (SNO), using pulsed laser deposition (PLD). AuNPs exhibited a dramatic variation in their growth mechanisms, depending on whether they were deposited on SNO thin films grown on magnesium oxide (SNO/MgO) or strontium titanate (SNO/STO) substrates. On SNO/MgO, the Au aggregates form large NPs with an average size of up to 3500 nm2. These AuNPs are triangular with sharp edges and corners. The out-of-plane direction of growth is favored, and the surface coverage ratio by AuNPs is low. When deposited on SNO/STO, the average size of AuNPs is much smaller, i.e., ∼250 nm2. This reduction in the average size is accompanied by an increase in the number density of NPs. AuNPs on SNO/STO have a round shape and high coverage ratio. Such an impact from the substrate selection on the AuNP structure is significant when the sandwiched SNO film is below 80 nm thickness and is weakened for 200 nm of SNO films. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize all samples. Strain analysis was used to explain the growth mechanism of AuNPs. The average height of AuNPs was measured by using atomic force microscopy (AFM). Ellipsometry in the visible-near-infrared (vis-NIR) region was used to characterize the optical response of all samples. AuNP-decorated SNO/MgO and SNO/STO thin films exhibit different optical properties, with only gold-decorated SNO/MgO samples showing a size-dependent epsilon-near-zero behavior of nanoparticles. These results provide an additional route to control the structure of AuNPs. They can be used for various plasmonic applications like the design and development of strain-engineered gold-nanoparticle-decorated devices for surface-enhanced Raman spectroscopy (SERS) and photocatalysis.

Characteristics of the postural stability of the lower limb in different visual states of undergraduate students with moderate myopia.

Objective: To explore the characteristics of lower limb postural stability in undergraduates with moderate myopia in three different visual states. Methods: Twenty male undergraduate students were recruited to complete respectively the static and dynamic postural stability tests under eyes-closed, myopia (taking off their glasses immediately) and corrected vision conditions. A three-dimensional force platform (Bertec, United States) was used to test static postural stability, which calculated the total path length of the Center of Pressure (COP), path length in the antero-posterior (A/P) and medio-lateral (M/L) directions, COP area, SampleEntropy (SampEn), and low-, medium-, and high-frequency spectrum energies. Dynamic postural stability was tested using the Y-balance test, and the Y-balance test scores were calculated. The Vicon three-dimensional motion capture system (Oxford, United Kingdom) measured the maximum flexion angles of the ankle, knee, and hip joints. The electromyography (EMG) root mean square (RMS) and integral EMG (iEMG) of the tibialis anterior and lateral gastrocnemius of the lower extremity were simultaneously measured using wireless surface electromyography (Noraxon, United States). Results: The SampEn-A/P and SampEn-M/L of corrected vision state higher than myopia and eyes-closed states, and myopia state larger than eyes-closed state (χ2 = 51.631, p < .001). The original and standard scores of the anterior, postero-medial and comprehensive values of the three visual states had significant differences (F = 32.125, p < .001). The original and standard values of postero-lateral corrected vision and myopia were larger than those of eyes-closed states (F = 37.972, p < .001). The maximum flexion angles of the ankle and knee joints were in the following order: corrected vision, myopia and eyes-closed (F = 10.93, p < .001). The iEMG and RMS had significant differences in the three different states (χ2 = 12.700, p < .001) in the all directions of YBT. Conclusion: Compared with corrected vision, the stability of static posture in the state of myopia was decreased, and the postural regularity was more regular. The dynamic postural stability in the state of myopia was also lower than that corrected vision, and the activation and work of ankle muscles were also increased.

Near-unity Raman ß-factor of surface-enhanced Raman scattering in a waveguide.

The Raman scattering of light by molecular vibrations is a powerful technique to fingerprint molecules through their internal bonds and symmetries. Since Raman scattering is weak1, methods to enhance, direct and harness it are highly desirable, and this has been achieved using optical cavities2, waveguides3-6 and surface-enhanced Raman scattering (SERS)7-9. Although SERS offers dramatic enhancements2,6,10,11 by localizing light within vanishingly small hot-spots in metallic nanostructures, these tiny interaction volumes are only sensitive to a few molecules, yielding weak signals12. Here we show that SERS from 4-aminothiophenol molecules bonded to a plasmonic gap waveguide is directed into a single mode with >99% efficiency. Although sacrificing a confinement dimension, we find a SERS enhancement of ~103 times across a broad spectral range enabled by the waveguide's larger sensing volume and non-resonant waveguide mode. Remarkably, this waveguide SERS is bright enough to image Raman transport across the waveguides, highlighting the role of nanofocusing13-15 and the Purcell effect16. By analogy to the ß-factor from laser physics10,17-20, the near-unity Raman ß-factor we observe exposes the SERS technique to alternative routes for controlling Raman scattering. The ability of waveguide SERS to direct Raman scattering is relevant to Raman sensors based on integrated photonics7-9 with applications in gas sensing and biosensing.

Correction to Graphene Plasmon Cavities Made with Silicon Carbide.

[This corrects the article DOI: 10.1021/acsomega.7b00726.].

Expert consensus on protocol of rehabilitation for COVID-19 patients using framework and approaches of WHO International Family Classifications.

Coronavirus disease 2019 (COVID-19) has widely spread all over the world and the numbers of patients and deaths are increasing. According to the epidemiology, virology, and clinical practice, there are varying degrees of changes in patients, involving the human body structure and function and the activity and participation. Based on the World Health Organization (WHO) International Classification of Functioning, Disability and Health (ICF) and its biopsychosocial model of functioning, we use the WHO Family of International Classifications (WHO-FICs) framework to form an expert consensus on the COVID-19 rehabilitation program, focusing on the diagnosis and evaluation of disease and functioning, and service delivery of rehabilitation, and to establish a standard rehabilitation framework, terminology system, and evaluation and intervention systems based the WHO-FICs.

Strategies of elite Chinese gymnasts in coping with landing impact from backward somersault.

This study aimed to investigate how elite Chinese gymnasts manage the landing impact from a backward somersault. Six international-level male gymnasts performed backward somersault tests with a synchronous collection of kinematics (250 Hz), ground reaction forces (1,000 Hz), and surface electromyography (EMG) (2,000 Hz). A 19-segment human model was developed and lower extremity joints torques were calculated by means of a computer simulation. The angles of the lower extremity joints initially extended and then flexed. These angular velocities of extension continued to decrease and the joint torques changed from extensor to flexor within 100 ms before touchdown. The angles of the hips, knees, and ankles flexed rapidly by 12°, 36°, and 29°, respectively, and the angular velocities of flexion, flexor torque, and EMG peaked sharply during the initial impact phase of the landing. The angles of the hips, knees, and ankles flexed at approximately 90°, 100°, and 80°, respectively. The torques were reversed with the extensor torques, showing a relatively high level of muscle activation during the terminal impact phase of the landing. The results showed that the international-level gymnasts first extended their lower extremity joints, then flexed just before touchdown. They continued flexing actively and rapidly in the initial impact phase and then extended to resist the landing impact and maintain body posture during the terminal impact phase of the landing. The information gained from this study could improve our understanding of the landings of elite gymnasts and assist in injury prevention.