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Designing reliable and energy-efficient memristors for artificial synaptic arrays in neuromorphic computing beyond von Neumann architecture remains a challenge. Here, memristors based on emerging layered nickel phosphorus trisulfide (NiPS3 ) are reported that exhibit several favorable characteristics, including uniform bipolar nonvolatile switching with small operating voltage (<1 V), fast switching speed (< 20 ns), high On/Off ratio (>102 ), and the ability to achieve programmable multilevel resistance states. Through direct experimental evidence using transmission electron microscopy and energy dispersive X-ray spectroscopy, it is revealed that the resistive switching mechanism in the Ti/NiPS3 /Au device is related to the formation and dissolution of Ti conductive filaments. Intriguingly, further investigation into the microstructural and chemical properties of NiPS3 suggests that the penetration of Ti ions is accompanied by the drift of phosphorus-sulfur ions, leading to induced P/S vacancies that facilitate the formation of conductive filaments. Furthermore, it is demonstrated that the memristor, when operating in quasi-reset mode, effectively emulates long-term synaptic weight plasticity. By utilizing a crossbar array, multipattern memorization and multiply-and-accumulate (MAC) operations are successfully implemented. Moreover, owing to the highly linear and symmetric multiple conductance states, a high pattern recognition accuracy of ≈96.4% is demonstrated in artificial neural network simulation for neuromorphic systems.
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The van der Waals (vdWs) heterostructures, with vertical layer stacking structure of various two-dimensional (2D) materials, maintain the reliable photonic characteristics while compensating the shortcomings of the participating individual components. In this work, we combine the less-studied multilayer tin selenide (SnSe2) thin film with one of the traditional 2D materials, graphene, to fabricate the graphene-based vdWs optical switching element (Gr-SnSe2) with superior broadband nonlinear optical response. The transient absorption spectroscopy (TAS) measurement results verify that graphene acts as the recombination channel for the photogenerated carrier in the Gr-SnSe2 sample, and the fast recovery time can be reduced to hundreds of femtoseconds which is beneficial for the optical modulation process. The optical switching properties are characterized by the I-scan measurements, exhibiting a saturable energy intensity of 2.82 mJ·cm-2 (0.425 µJ·cm-2) and a modulation depth of 15.6% (22.5%) at the wavelength of 1030â nm (1980nm). Through integrating Gr-SnSe2 with a cladding waveguide, high-performance picosecond Q-switched operation in the near-infrared (NIR) and mid-infrared (MIR) spectral regions are both achieved. This work experimentally demonstrates the great potential of graphene-based vdWs heterostructures for applications in broadband ultrafast photonics.
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The management of ecological water conveyance (EWC) can allow riparian vegetation communities to survive the threat of degradation in hyperarid inland areas and promote the health of groundwater-recharged riparian ecosystems. However, the ultrashort-term effects of periodic EWC scheduling on riparian vegetation remain unclear. This study explored the spatiotemporal differentiation in species structure (herbs, shrubs, and trees), diversity (measured by the Simpson, Shannon-Wiener, Pielou, and Margalef indices), stability (evaluated via Godron fitting distances and abundance-biomass comparison curves), and integrity (proxied by the vegetation-based index of biotic integrity) of vegetation communities in the downstream Heihe River Basin, China. Empirical orthogonal function, Pearson correlation, canonical correspondence analysis (CCA), and partial CCA methods were used to evaluate the effects of dominant habitat environmental factors from the hydrogeographic features, soil physicochemical properties, and anthropogenic impacts. The results showed that the riparian vegetation community diversity, stability, and integrity varied moderately to slightly with hierarchical distance from near wetlands (<200 m; containing mainly herbs) to far desert edges (>800 m; occupied by shrubs/subshrubs). The middle transition zone (200-800 m; occupied mostly by trees/subtrees) had the best diversity and integrity but relatively poor stability. The most significant influencing factors were EWC and soil moisture. The simple diversity, fair-level integrity, and disturbed but not irreversibly damaged stability of the vegetation community were generally improved by 14.82%, 20.33%, and 30.57%, respectively, in the pre-EWC period but worsened in the post-EWC period. The difference in spatially distributed EWC quantities caused more apparent vegetation restoration in high water-supplied subareas where certain biological community instability existed. Therefore, adequate EWC management can be considered a prerequisite for the maintenance of high richness and structural stability in local communities and requires a good balance between interregional vegetation abundance and enhanced environmental tolerance.
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Ecossistema , Água , Rios/química , Solo , Árvores , Áreas AlagadasRESUMO
We demonstrate second harmonic generations in quasi-phase matched cladding waveguide structures fabricated by direct femtosecond laser writing. Waveguides with circular section are inscribed in z-cut MgO doped stoichiometric lithium tantalate with fan-out χ(2) grating structures. The ferroelectric domain-inverted fan-out grating period seamlessly varies from 7.5 to 8.2 µm. Seven individual waveguides with step changed periods are fabricated. The minimum insertion loss of the cladding waveguides is about 0.54 dB at wavelength of 1064 nm. Temperature tuned second harmonic generations of 1064 nm for different quasi phase matched grating periods are demonstrated by using continuous wave and pulsed laser. A comparable normalized conversion efficiency of 3.55%/(W·cm2) is obtained for 7.91 µm period. The maximum power conversion efficiency of 54.3% was obtained under a pump peak power of 282 W.
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We report on the fabrication of depressed cladding waveguides in periodically poled MgO doped LiTaO3 by using low-repetition-rate femtosecond laser writing, and their use for guided-wave second harmonic generation (SHG). The cladding waveguides exhibit different guiding performance along the extraordinary and ordinary polarizations. The temperature-dependent quasi-phase-matching (QPM) is realized to obtain SHG in the depressed cladding waveguides. The results show that the QPM temperature was dependent on the poling period and on the features of the cladding waveguides. The highest nonlinear conversion efficiency (0.74%W-1cm-2) was found in the waveguide fabricated with large scanning velocity (0.75 mm/s) and small radius (15 µm).
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We report on the fabrication of ring-shaped waveguides operating at the telecommunication band in a cubic Bi4Ge3O12 (BGO) crystal by using technique of femtosecond laser writing. In the regions of laser written tracks in BGO crystal, positive refractive index is induced, resulting in so-called Type I configuration. The modal profiles are within the designed track cladding with ring-shaped geometries, which are analogous to circular optical lattices. The homogenous guidance along both TE and TM polarizations has been obtained at telecommunication wavelength of 1.55 µm. Both straight and S-curved waveguiding structures have been produced with ring-shaped configurations. This work paves the way to fabricate complex photonic networks for telecommunications by using ring-shaped waveguides in compact chips.
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Reservoir computing (RC), a variant of recurrent neural networks (RNNs), is well-known for its reduced energy consumption through exclusive focus on training the output weight and its superior performance in handling spatiotemporal information. Implementing these networks in hardware requires devices with superior fading memory behavior. Unlike filament-based two-terminal devices, those relying on ferroelectric switching demonstrate improved voltage reliability, while three-terminal transistors provide additional active control. HfO2-based ferroelectric materials such as Hf0.5Zr0.5O2 (HZO), have garnered attention for their scalability and seamless integration with CMOS technology. This study implements a RC hardware based on MoS2-HZO integrated device structure with enhanced spontaneous polarization field. By adjusting the oxygen vacancy concentration, the devices exhibit consistent responses to both identical and nonidentical voltages, making them suitable for diverse RC applications. The high accuracy of MNIST handwritten digits recognition highlights the rich reservoir states of the traditional RC architecture. Additionally, the impact of masks on RC implementation is assessed, showcasing the device's capability for spatiotemporal signal analysis. This development paves the way for implementing energy-efficient and high-performance computing solutions.
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The development of all-in-one devices for artificial visual systems offers an attractive solution in terms of energy efficiency and real-time processing speed. In recent years, the proliferation of smart sensors in the growth of Internet-of-Things (IoT) has led to the increasing importance of in-sensor computing technology, which places computational power at the edge of the data-flow architecture. In this study, a prototype visual sensor inspired by the human retina is proposed, which integrates ferroelectricity and photosensitivity in two-dimensional (2D) α-In2Se3 material. This device mimics the functions of photoreceptors and amacrine cells in the retina, performing optical reception and memory computation functions through the use of electrical switching polarization in the channel. The gate-tunable linearity of excitatory and inhibitory functions in photon-induced short-term plasticity enables to encode and classify 12 000 images in the Mixed National Institute of Standards and Technology (MNIST) dataset with remarkable accuracy, achieving ≈94%. Additionally, in-sensor convolution image processing through a network of phototransistors, with five convolutional kernels electrically pre-programmed into the transistors is demonstrated. The convoluted photocurrent matrices undergo straightforward arithmetic calculations to produce edge and feature-enhanced scenarios. The findings demonstrate the potential of ferroelectric α-In2Se3 for highly compact and efficient retinomorphic hardware implementation, regardless of ambipolar transport in the channel.
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To develop and validate scales for reliably assessing dementia and urinary incontinence knowledge of older adults in the community. Items were generated through a literature review, refined through a Delphi study (n = 19), and then revised through a pilot study (n = 29). Item analysis and exploratory factor analysis were applied to finalize the scales (n = 244). Construct validity, reliability, and acceptability were evaluated (n = 243). The two knowledge assessment scales for dementia and urinary incontinence, respectively, comprised 12 items and 8 items. Model fit indicators of both met the criteria of confirmatory factor analysis. Cronbach's α were .82 and .70, respectively. Completion ratio and completion time of the two scales was 83.51% and 4.22 ± 1.90 minutes. The knowledge assessment scales for dementia and urinary incontinence with satisfactory validity, reliability, and acceptability, could be served as valid tools for disease prevention and management among older adults in the community.
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Demência , Incontinência Urinária , Humanos , Incontinência Urinária/diagnóstico , Demência/diagnóstico , Idoso , Feminino , Reprodutibilidade dos Testes , Masculino , Inquéritos e Questionários/normas , Idoso de 80 Anos ou mais , Conhecimentos, Atitudes e Prática em Saúde , Psicometria , Técnica Delphi , Análise Fatorial , Projetos Piloto , Vida IndependenteRESUMO
BACKGROUND: Previously published meta-epidemiological studies focused on Western medicine have identified some trial characteristics that impact the treatment effect of randomized controlled trials (RCTs). Nevertheless, it remains unclear if similar associations exist in RCTs on Chinese herbal medicine (CHM). Further, Chinese medicine-related characteristics have not been explored yet. OBJECTIVE: To investigate trial characteristics related to treatment effect estimates on CHM RCTs. SEARCH STRATEGY: This meta-epidemiological study searched 5 databases for systematic reviews on CHM treatment published between January 2011 and July 2021. INCLUSION CRITERIA: An eligible systematic review should only include RCTs of CHM and conduct at least one meta-analysis. DATA EXTRACTION AND ANALYSIS: Two reviewers independently conducted data extraction on general characteristics of systematic reviews, meta-analyses and included RCTs. They also assessed the risk of bias of RCTs using the Cochrane risk of bias tool. A two-step approach was used for data analyses. The ratio of odds ratios (ROR) and difference in standardized mean differences (dSMD) with 95% confidence interval (CI) were applied to present the difference in effect estimates for binary and continuous outcomes, respectively. RESULTS: Ninety-one systematic reviews, comprising 1338 RCTs were identified. For binary outcomes, RCTs incorporated with syndrome differentiation (ROR: 1.23; 95 % CI: [1.07, 1.39]), adopting Chinese medicine formula (ROR: 1.19; 95% CI: [1.03, 1.34]), with low risk of bias on incomplete outcome data (ROR: 1.29; 95% CI: [1.06, 1.52]) and selective outcome reporting (ROR: 1.12; 95% CI: [1.01, 1.24]), as well as a trial size ≥ 100 (ROR: 1.23; 95% CI: [1.04, 1.42]) preferred to show larger effect estimates. As for continuous outcomes, RCTs with Chinese medicine diagnostic criteria (dSMD: 0.23; 95% CI: [0.06, 0.41]), judged as high/unclear risk of bias on allocation concealment (dSMD: -0.70; 95% CI: [-0.99, -0.42]), with low risk of bias on incomplete outcome data (dSMD: 0.30; 95% CI: [0.18, 0.43]), conducted at a single center (dSMD: -0.33; 95% CI: [-0.61, -0.05]), not using intention-to-treat analysis (dSMD: -0.75; 95% CI: [-1.43, -0.07]), and without funding support (dSMD: -0.22; 95% CI: [-0.41, -0.02]) tended to show larger effect estimates. CONCLUSION: This study provides empirical evidence for the development of a specific critical appraisal tool for risk of bias assessments on CHM RCTs. Please cite this article as: Wang BH, Lin YL, Gao YY, Song JL, Qin L, Li LQ, Liu WQ, Zhong CCW, Jiang MY, Mao C, Yang XB, Chung VCH, Wu IXY. Trial characteristics and treatment effect estimates in randomized controlled trials of Chinese herbal medicine: A meta-epidemiological study. J Integr Med. 2024; 22(3): 223-234.
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Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Ensaios Clínicos Controlados Aleatórios como Assunto , Humanos , Medicamentos de Ervas Chinesas/uso terapêutico , Estudos Epidemiológicos , Resultado do TratamentoRESUMO
This paper presents an advanced method that combines coupling-of-modes (COM) theory and the finite element method (FEM), which enables the quick extraction of COM parameters and the accurate prediction of the electroacoustic and temperature behavior of surface acoustic wave (SAW) devices. For validation, firstly, the proposed method is performed for a normal SAW resonator. Then, the validated method is applied to analysis of an I.H.P. SAW resonator based on a 29°YX-LT/SiO2/SiC structure. Via optimization, the electromechanical coupling coefficient (K2) is increased up to 13.92% and a high quality (Q) value of 1265 is obtained; meanwhile, the corresponding temperature coefficient of frequency (TCF) is -10.67 ppm/°C. Furthermore, a double-mode SAW (DMS) filter with low insertion loss and excellent temperature stability is also produced. It is demonstrated that the proposed method is effective even for SAW devices with complex structures, providing a useful tool for the design of SAW devices with improved performance.
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AIM: This study aimed to develop and validate sarcopenia and fall knowledge assessment scales for community-dwelling older adults. METHODS: A five-phase, systematic and standardized process was used. Phase 1: item pools were constructed based on the Symptom Interpretation Model. Phase 2: the Delphi expert consultation was carried out for items selection and revision. Phase 3: a pilot survey was carried out to further select and revise the items. Phase 4: older adults were surveyed to finalize the items. Phase 5: older adults were surveyed to test the psychometric properties of the two developed scales, including construct validity, reliability and acceptability. RESULTS: Both scales comprise three dimensions (symptom, risk factor and management strategy), with 10 items for the sarcopenia knowledge assessment scale and 14 items for the fall knowledge assessment scale. They had acceptable construct validity, with all indicators meeting their specific criteria. Their reliability was acceptable, with the Cronbach's α coefficients being 0.82 for both scales, the value of spilt-half reliability being 0.86 for the sarcopenia knowledge assessment scale and 0.85 for the fall knowledge assessment scale. Their acceptability was good, with both scales having a completion rate of 94.35% and an average completion time of 5 min. DISCUSSION: Two Chinese knowledge assessment scales with acceptable validity, reliability and acceptability have been developed, which will facilitate the assessment of the knowledge on sarcopenia and fall among community-dwelling older adults, especially for large-scale surveys. Geriatr Gerontol Int 2023; 23: 430-436.
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Acidentes por Quedas , Conhecimentos, Atitudes e Prática em Saúde , Sarcopenia , Idoso , Humanos , População do Leste Asiático , Vida Independente , Psicometria , Reprodutibilidade dos Testes , Fatores de Risco , Sarcopenia/diagnóstico , Inquéritos e QuestionáriosRESUMO
SAW devices with a multi-layered piezoelectric substrate have excellent performance due to advantages such as a high quality factor, Q, low loss insertion, large bandwidth, etc. Prior to manufacturing, a comprehensive analysis and proper design are essential to evaluating the device's key performance indicators, including the Bode Q value, bandwidth, and transverse mode suppression. This study explored the performance of SAW resonators employing a 42°Y-X LiTaO3 (LT) thin-plate-based multi-layered piezoelectric substrate. The thicknesses for each layer of the 42°Y-X LT/SiO2/poly-Si/Si substrate were optimized according to the index of phase velocity, Bode Q value, and bandwidth. The effect of the device structure parameters on the dispersion curve and slowness curve was studied, and a flat slowness curve was found to be favorable for transverse mode suppression. In addition, the design of the dummy configuration was also optimized for the suppression of spurious waves. Based on the optimized design, a one-port resonator on the 42°Y-X LT/SiO2/poly-Si/Si substrate was fabricated. The simulation results and measurements are presented and compared, which provides guidelines for the design of new types of SAW devices configured with complex structures.
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CubeSats were conceived with an aim to provide students with hands-on, design, build, and test experiences on spacecraft. Many education-class CubeSats keep the cost of the projects low with the use of commercial off-the-shelf (COTS) products. But using parts not designed for space missions often means a compromise in performance (e.g., low sensor accuracy, low power efficiency) and reliability, which makes component testing a necessary part of the development process. Unfortunately, there is no single lab equipment that can test the integrated features of CubeSats, including the radio communication over ranges of altitudes and distances. It has been pointed out that a high altitude reached by a weather balloon offers an environment similar to the space environment. This paper describes a balloon flight testing of Arduino and sensors for a CubeSat "prototype"-a preliminary mock-up model used for hardware selection and validation during the initial building phase. Atmospheric pressures and temperatures were measured throughout the balloon flight. The measured pressures were validated by comparing Arduino's pressure altitudes against the GPS altitudes, and the measured temperatures were assessed against the standard atmosphere model.
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BACKGROUND: Hepatocellular Carcinoma (HCC), the second leading cause of cancer-related mortality with over half a million new cases diagnosed annually in the world, accounts for nearly 70% of cancer deaths in parts of Asia and Africa. Podophyllum, one of the important members of the lignane class of natural products derived from plants in Podophyllum peltatum L., has been shown to suppress tumor growth in various cancers. However, the effects of Podophyllum compounds on HCC and the mechanisms for its tumor-suppressive function remain unknown. METHODS: A molecular docking study was employed to the analysis of the interaction between compounds and their targeted proteins. Cell proliferation was measured by MTT assay. Western blot analysis was used to evaluate protein expression. qRT-PCR was performed to assess RNA expression. RESULTS: Molecular docking analysis was consistent with the beneficial effect of fluorine atom substituent in the 3-position of 2-aminopyridine in our previous study. Also, P-3F and D-3F displayed the most potent cytotoxicities against PLC/PRF/5 with p53-R249S and weakest inhibition of L02 (normal liver cell) growth. However, these derivatives had no effect on the suppression of HepG2 (wild-type p53) and Hep3B (p53-null) proliferation significantly. Further study showed that both compounds increase γ-H2AX expression in PLC/PRF/5 cell, along with repression of the c-Myc activation, purportedly by induction of p53 level and transcriptional activation. CONCLUSION: The results suggested that podophyllum derivatives containing fluorine atom in the 3-position of 2- aminopyridine could inhibit the growth of HCC harboring p53-R249S by restoring the activity of p53 with decreasing the level of c-Myc.
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Antineoplásicos Fitogênicos/farmacologia , Produtos Biológicos/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Neoplasias Hepáticas/tratamento farmacológico , Podophyllum/química , Proteína Supressora de Tumor p53/metabolismo , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
River channel confluences are widespread in natural rivers. Understanding their unique hydrodynamic characteristics and contaminant transport rules may facilitate the rational and effective treatment of the water environment. In this study, we considered the Xitiaoxi River Basin as the research area, and a well-designed flume was established based on the extracted water system features. Hydrodynamically, in the Y-shaped confluence channel the flow velocity was easy to separate at the confluence, and a low flow velocity region appeared in the two branches. The spiral flow mainly flowed counterclockwise to the downstream region and the spiral trend increased as the discharge ratio decreased. The spiral flow and its effect on the transport and blending of contaminants were distinct between Y-shaped and asymmetrical river confluences. Based on the flow dynamics test, a set of pollutant discharge devices and a multi-point electrolytic conductivity meter were employed to research the mixing rule for pollutants. A high concentration zone for pollutants was likely to occur near the intersection, and the contaminant concentration band after the confluence was first compressed and then diffused. In particular, line source discharge in the left branch and the point source discharge in the inner bank of the left branch and in the outer bank of the right branch were dominant, and were conducive to the detection and treatment of pollutants.
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Hidrodinâmica , Rios , Poluentes da Água , China , Poluentes Ambientais , Poluição da ÁguaRESUMO
The femtosecond laser micromachining of transparent optical materials offers a powerful and feasible solution to fabricate versatile photonic components towards diverse applications. In this work, we report on a new design and fabrication of ridge waveguides in LiNbO3 crystal operating at the mid-infrared (MIR) band by all-femtosecond-laser microfabrication. The ridges consist of laser-ablated sidewalls and laser-written bottom low-index cladding tracks, which are constructed for horizontal and longitudinal light confinement, respectively. The ridge waveguides are found to support good guidance at wavelength of 4 µm. By applying this configuration, Y-branch waveguiding structures (1 × 2 beam splitters) have been produced, which reach splitting ratios of â¼1:1 at 4 µm. This work paves a simple and feasible way to construct novel ridge waveguide devices in dielectrics through all-femtosecond-laser micro-processing.