Deep learning in the precise assessment of primary Sjögren's Syndrome based on ultrasound images.

OBJECTIVES: This study aimed to investigate the value of a deep learning (DL) model based on greyscale ultrasound (US) images for precise assessment and accurate diagnosis of primary Sjögren's syndrome (pSS). METHODS: This was a multicentre prospective analysis. All pSS patients were diagnosed according to 2016 ACR/EULAR criteria. 72 pSS patients and 72 sex- and age-matched healthy controls recruited between January 2022 and April 2023, together with 41 patients and 41 healthy controls recruited from June 2023 to February 2024 were used for DL model development and validation, respectively. DL model was constructed based on the ResNet 50, input with preprocessed all participants' bilateral submandibular glands (SMGs), parotid glands (PGs), and lacrimal glands (LGs) greyscale US images. Diagnostic performance of the model was compared with two radiologists. The accuracy of prediction and identification performance of DL model were evaluated by calibration curve. RESULTS: 864 and 164 greyscale US images of SMGs, PGs, and LGs were collected for development and validation of the model. The AUCs of DL model in the SMG, PG, and LG were 0.92, 0.93, 0.91 in the model cohort, and were 0.90, 0.88, 0.87 in the validation cohort respectively, outperforming both radiologists. Calibration curves showed the prediction probability of DL model were consistent with the actual probability in both model cohort and validation cohort. CONCLUSION: DL model based on greyscale US images showed diagnostic potential in the precise assessment of pSS patients in the SMG, PG, and LG, outperforming conventional radiologist evaluation.

From Forearm to Wrist: Deep Learning for Surface Electromyography-Based Gesture Recognition.

Though the forearm is the focus of the prostheses, myoelectric control with the electrodes on the wrist is more comfortable for general consumers because of its unobtrusiveness and incorporation with the existing wrist-based wearables. Recently, deep learning methods have gained attention for myoelectric control but their performance is unclear on wrist myoelectric signals. This study compared the gesture recognition performance of myoelectric signals from the wrist and forearm between a state-of-the-art method, TDLDA, and four deep learning models, including convolutional neural network (CNN), temporal convolutional network (TCN), gate recurrent unit (GRU) and Transformer. It was shown that with forearm myoelectric signals, the performance between deep learning models and TDLDA was comparable, but with wrist myoelectric signals, the deep learning models outperformed TDLDA significantly with a difference of at least 9%, while the performance of TDLDA was close between the two signal modalities. This work demonstrated the potential of deep learning for wrist-based myoelectric control and would facilitate its application into more sections.

Multicolor, injectable BSA-based lanthanide luminescent hydrogels with biodegradability.

Protein hydrogels have attracted increasing attention because of their excellent biodegradability and biocompatibility, but frequently suffer from the single structures and functions. As a combination of luminescent materials and biomaterials, multifunctional protein luminescent hydrogels can exhibit wider applications in various fields. Herein, we report a novel, multicolor tunable, injectable, and biodegradable protein-based lanthanide luminescent hydrogel. In this work, urea was utilized to denature BSA to expose disulfide bonds, and tris(2-carboxyethyl)phosphine (TCEP) was employed to break the disulfide bonds in BSA to generate free thiols. A part of free thiols in BSA rearranged into disulfide bonds to form a crosslinked network. In addition, lanthanide complexes (Ln(4-VDPA)3), containing multiple active reaction sites, could react with the remaining thiols in BSA to form the second crosslinked network. The whole process avoids the use of nonenvironmentally friendly photoinitiators and free radical initiators. The rheological properties and structure of hydrogels were investigated, and the luminescent performances of hydrogels were studied in detail. Finally, the injectability and biodegradability of hydrogels were verified. This work will provide a feasible strategy for the design and fabrication of multifunctional protein luminescent hydrogels, which may have further applications in biomedicine, optoelectronics, and information technology.

Organophosphine as an Alkyl Transfer Shuttle for the Direct ß-Alkylation of Chalcones Using Alkyl Halides.

We report an efficient alkyl transfer strategy for the direct ß-alkylation of chalcones using commercially available alkyl bromides as alkyl reagents. In this transformation, the ortho-phosphanyl substituent in the chalcones is crucial for controlling their reactivity and selectivity. It also serves as a reliable alkyl transfer shuttle to transform electrophilic alkyl bromides into nucleophilic alkyl species in the form of quaternary phosphonium salts and transfer the alkyl group effectively to the ß-position of the chalcones. This alkyl transfer strategy can be further extended to the alkenylation of ortho-phosphanyl benzaldehydes to assemble functionalized polyenes.

Substrate-directed divergent synthesis of fused indole polycycles through Rh(II)-catalyzed cascade reactions of bis(diazo)indolin-2-ones.

Herein, we report a substrate-directed diverse synthetic strategy toward two kinds of structurally intriguing fused indole polycycles through Rh(II)-catalyzed cascade reactions of bis(diazo)indolin-2-ones with enaminones. The subtle structural changes in enaminones lead to different reactivities. Cyclic enaminones produce indolo[2,3-b]indoles, whereas acyclic ones afford oxazolo[3,2-a]indoles.

Diastereoselective construction of bridged piperidines through an interrupted dearomative reduction.

An interrupted dearomative reduction strategy was developed to transform planar chalcone-based pyridinium salts into structurally intriguing bridged piperidines in a completely regio- and diastereoselective manner. This reaction proceeded successfully by using cheap and easily accessible NaBH4 as the reductant under mild conditions without exclusion of oxygen or use of special equipment.

A combination of polarity reversal, Diels-Alder cycloaddition and skeletal remodeling to access pyridine-fused nitrones.

An unprecedented cascade strategy consisting of polarity reversal, normal electron-demand Diels-Alder cycloaddition and skeletal remodeling was developed to construct novel pyridine-fused nitrones in up to 82% yield. The key to the success was the umpolung process, which transformed the electron-deficient 3-nitropyridinium ring into a reactive, π-extended cyclic nitroalkene, serving as a rarely reported hetero-diene to participate in normal Diels-Alder cycloadditions.

Color-tunable, self-healing albumin-based lanthanide luminescent hydrogels fabricated by reductant-triggered gelation.

Luminescent hydrogels show extensive applications in many fields because of their excellent optical properties. Although there are many matrixes used to prepare luminescent hydrogels, the synthesis of protein-based luminescent hydrogels is still urgently needed to explore due to their good biodegradability and biocompatibility. In this work, a color-tunable, self-healing protein-based luminescent hydrogel consisting of bovine serum albumin (BSA) and lanthanide complexes is prepared via reductant-triggered gelation. Firstly, a bifunctional organic ligand named 4-(phenylsulfonyl)-pyridine-2,6-dicarboxylic acid (4-PSDPA) is synthesized, which can react with thiol groups and effectively sensitize the luminescence of Eu3+ and Tb3+ ions. Then, the BSA is treated with a reducing agent tris(2-carboxyethyl)phosphine (TCEP) to produce thiol groups. And the newly formed thiol groups can re-match to form disulfide bonds between two BSA molecules or react with Ln(4-PSDPA)3 complexes, resulting in the formation of an albumin-based luminescent hydrogel. Furthermore, the self-healing, biodegradability and biocompatibility of albumin-based hydrogels have also been demonstrated. We expect that the newly developed multifunctional protein-based hydrogels will find potential applications in the fields of biomedical engineering and optical devices.

Self-powered and high responsivity photodetector based on a n-Si/p-GaTe heterojunction.

Heterojunction integrated by two-dimensional/three-dimensional materials has shown great potential applications in optoelectronic devices because of its fast response speed, high specific detectivity and broad spectral response. In this work, the vertical n-Si/p-GaTe heterojunction has been designed and fabricated, which shows a high responsivity up to 5.73 A W-1and a fast response time of 20µs at zero bias benifitting from the high efficiency of light absorption, internal photocurrent gain and strong built-in electrical field. A specific detectivity of 1012Jones and a broad spectral response ranging from 300 to 1100 nm can also be achieved. This work provides an alternative strategy for high-performance self-powered optoelectronic devices.

N-type doping of black phosphorus single crystal by tellurium.

Black phosphorus has many potential applications in optoelectronic devices because of its unique properties. Adjusting its performance by doping is an important issue of research. In this paper, we synthesized high-quality Te-doped crystals by the chemical vapor transport method. Tellurium doping with an atomic ratio of 0.1% was confirmed by X-ray photoelectron spectroscopy, X-ray diffraction, and energy dispersive X-ray analysis. The performance of field effect transistors devices shows that the hole mobility of Te-doped black phosphorous (BP) is significantly improved compared with that of undoped-BP. The highest hole mobility at room temperature is 719 cm2 V-1 s-1, and the electron mobility is 63 cm2 V-1 s-1. Te-doped BP field effect transistors show an obvious bipolar behavior.

P-type Doping in Large-Area Monolayer MoS2 by Chemical Vapor Deposition.

Molybdenum disulfide (MoS2) with excellent properties has been widely reported in recent years. However, it is a great challenge to achieve p-type conductivity in MoS2 because of its native stubborn n-type conductivity. Substitutional transition metal doping has been proved to be an effective approach to tune their intrinsic properties and enhance device performance. Herein, we report the growth of Nb-doping large-area monolayer MoS2 by a one-step salt-assisted chemical vapor deposition method. Electrical measurements indicate that Nb doping suppresses n-type conductivity in MoS2 and shows an ambipolar transport behavior after annealing under the sulfur atmosphere, which highlights the p-type doping effect via Nb, corresponding to the density functional theory calculations with Fermi-level shifting to valence band maximum. This work provides a promising approach of two-dimensional materials in electronic and optoelectronic applications.

Nitenpyram disturbs gut microbiota and influences metabolic homeostasis and immunity in honey bee (Apis mellifera L.).

Recently, environmental risk and toxicity of neonicotinoid insecticides to honey bees have attracted extensive attention. However, toxicological understanding of neonicotinoid insecticides on gut microbiota is limited. In the present study, honey bees (Apis mellifera L.) were exposed to a series of nitenpyram for 14 days. Results indicated that nitenpyram exposure decreased the survival and food consumption of honey bees. Furthermore, 16S rRNA gene sequencing revealed that nitenpyram caused significant alterations in the relative abundance of several key gut microbiotas, which contribute to metabolic homeostasis and immunity. Using high-throughput RNA-Seq transcriptomic analysis, we identified a total of 526 differentially expressed genes (DEGs) that were significantly altered between nitenpyram-treated and control honey bee gut, including several genes related to metabolic, detoxification and immunity. In addition, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed nitenpyram affected several biological processes, of which most were related to metabolism. Collectively, our study demonstrates that the dysbiosis of gut microbiota in honey bee caused by nitenpyram may influence metabolic homeostasis and immunity of bees, and further decrease food consumption and survival of bees.

Flumethrin at sublethal concentrations induces stresses in adult honey bees (Apis mellifera L.).

Flumethrin is a typical pyrethroid varroacide widely used for mite control in beekeeping worldwide. Currently, information on the toxicological characteristics of flumethrin on bees at sublethal concentrations is still lacking. To fill this gap in information, we performed a 48-h acute oral and 14-day chronic toxicity testing of flumethrin in newly emerged adult honey bees under laboratory conditions. Results showed that flumethrin had high acute toxicity to honey bees with a 48-h LD50 of 0.47 µg/bee (95% CI, 0.39 ∼ 0.57 µg/bee), which is higher than that of many other commercial pyrethroid insecticides, but lower than that of tau-fluvalinate. After 14 days of chronic exposure to flumethrin at 0.01, 0.10, and 1.0 mg/L, significant antioxidant response, detoxification, immune reaction, and apoptosis were observed in the midguts. These findings indicated that flumethrin had potential risks to bees, and it can disturb the homeostasis of bees at sublethal concentrations under longer exposure conditions. Flumethrin is highly lipophilic and easy to accumulate in beeswax; thus, careless practices might pose risks to colony development in commercial beekeeping and native populations. This laboratory study can serve as an early warning, and further studies are required to understand the real residual level of flumethrin in bees and the risks of flumethrin in field condition.

Design of a two-layer structure to significantly improve the performance of zinc oxide resistive memory.

Resistive random access memory (RRAM) is considered to be one of the important candidates for the next generation of memory devices. Zinc oxide resistive memory has also been studied for many years, but there are still some controversial topics and problems. Herein, an unusual resistance state has been observed in devices following the measurement and analysis of ZnO resistive memories with different thicknesses, a middle resistance state was speculated to explain the instability of ZnO RRAM. According to this speculation, a two-layer structure ZnO RRAM has been designed to significantly increase the device performance with the introduction of an HfO2 layer and the enhancement has also been explained based on the results of first-principles calculations.

Improvement in the quality of black phosphorus by selecting a mineralizer.

The low-cost synthesis of high-quality black phosphorus (BP) has always been a challenge. Herein, we selected different mineralizers to synthesize high-crystallinity BP by the chemical vapor transport (CVT) method and demonstrated that the use of Pb instead of Sn can lead to higher purity BP. Residual Sn in Sn-BP was confirmed by X-ray photoelectron spectroscopy (XPS), but no mineralizer impurity was observed in Pb-BP. The performance of FET devices showed that the hole mobility of Pb-BP was significantly higher than that of Sn-BP. On the other hand, the Pb-BP devices exhibited good bipolarity with the highest hole mobility of 523 cm2 V-1 s-1 at room temperature and electron mobility of up to 28 cm2 V-1 s-1.

HfO2-passivated black phosphorus field effect transistor with long-termed stability and enhanced current on/off ratio.

Enhanced on/off ratio, obvious threshold voltage left shift, newly emerging bipolar field effect performance and most importantly, excellent stability in ambient condition have been reported for the HfO2-passivated black phosphorus field effect transistors . Both Raman spectra and x-ray photoelectron spectroscopy (XPS) show a thickness reduction effect after HfO2 passivation, XPS further demonstrates that the formation of P-Hf and P-O chemical bonds contributes to the thinning of layered black phosphorus (BP), in which P-Hf bonds also provide chemical protection for BP flakes from degradation. Atomic force microscopy measures the thickness of the passivation layer and also verifies the stability of the passivated BP flakes.

Metal-assisted exfoliation of few-layer black phosphorus with high yield.

We introduce a metal-assisted exfoliation method to produce few-layer black phosphorus with the lateral size larger than 50 µm and the area 100 times larger than those exfoliated using the normal "scotch-tape" technique. Using a field effect transistor it was found the hole mobility is 68.6 cm2 V-1 s-1 and the current on/off ratio can reach about 2 × 105.

Surface charge transfer doping of monolayer molybdenum disulfide by black phosphorus quantum dots.

Monolayer molybdenum disulfide (MoS2), consisting of covalently bonded S-Mo-S sandwiched layers, has high carrier mobility and a direct bandgap of 1.8 eV, offering properties for electronic and optoelectronic devices with high performance. Usually, it is essential to modulate the carrier concentrations and conductivities of monolayer MoS2 for practical applications. In this paper, black phosphorus (BP) quantum dots (QDs) were synthesized by a liquid exfoliation method successfully, and have a diameter of ∼5 nm as confirmed with a transmission electron microscope (TEM). BP QDs were utilized to decorate monolayer MoS2 grown by chemical vapor deposition (CVD). The Raman and PL spectra of the BP QD/MoS2 hybrid structure clearly indicate that BP QDs are an effective n-type doping scheme for monolayer MoS2. Back-gated monolayer MoS2 transistors were fabricated and show an improved source-drain current after BP QD modifications. A high electron concentration of ∼5.39 × 1012 cm-2 in monolayer MoS2 was achieved, which is beneficial for designing FETs and photodetector devices with novel functions.