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Surface-enhanced Raman spectroscopy (SERS) has emerged as a highly sensitive trace detection technique in recent decades, yet its exceptional performance remains elusive in semiconductor materials due to the intricate and ambiguous nature of the SERS mechanism. Herein, we have synthesized MoS2 nanoflowers (NFs) decorated with Au nanoparticles (NPs) by hydrothermal and redox methods to explore the size-dependence SERS effect. This strategy enhances the interactions between the substrate and molecules, resulting in exceptional uniformity and reproducibility. Compared to the unadorned Au nanoparticles (NPs), the decoration of Au NPs induces an n-type effect on MoS2, resulting in a significant enhancement of the SERS effect. This augmentation empowers MoS2 to achieve a low limit of detection concentration of 2.1 × 10-9 M for crystal violet (CV) molecules and the enhancement factor (EF) is about 8.52 × 106. The time-stability for a duration of 20 days was carried out, revealing that the Raman intensity of CV on the MoS2/Au-6 substrate only exhibited a reduction of 24.36% after undergoing aging for 20 days. The proposed mechanism for SERS primarily stems from the synergistic interplay among the resonance of CV molecules, local surface plasma resonance (LSPR) of Au NPs, and the dual-step charge transfer enhancement. This research offers comprehensive insights into SERS enhancement and provides guidance for the molecular design of highly sensitive SERS systems.
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Background: To explore how to prevent the social isolation of the older adult, this study constructed a model of the influence of community environmental satisfaction on the social isolation of the older adult from the three dimensions of environmental facilities, transportation, and supporting facilities around the community. Methods: The social network scale and environmental satisfaction scale were used to collect the sample data of nine communities in Xi'an, and the maximum likelihood estimation method was used to analyze the data and test the model. Results: (1) Environmental facilities, transportation, and community surrounding facilities promoted community environment satisfaction (R2 = 0.904). Among them, environmental facilities (ß = 0.869) had the greatest impact on community environmental satisfaction, followed by transportation (ß = 0.118), and surrounding facilities (ß = 0.084) had the least impact on community environmental satisfaction. (2) Environmental satisfaction had a direct positive impact on social isolation. Among them, the impact of environmental satisfaction on friend isolation (R2 = 0.895, ß = 0.829) was greater than that on family isolation (R2 = 0.718, ß = 0.747). Conclusion: Environmental satisfaction can directly affect the social isolation of the older adult in the community and can be used as an intermediate variable of environmental facilities, transportation, and surrounding facilities in the community so that it can indirectly affect the social isolation of the older adult. The results of this study provide a scientific basis for the design of aging environments in the future.
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Medio Social , Aislamiento Social , Satisfacción Personal , AmbienteRESUMEN
Graphene p-n junctions have important applications in the fields of optical interconnection and low-power integrated circuits. Most current research is based on the lateral p-n junction prepared by chemical doping and other methods. Here, we report a new type of pure graphene oxide (pGO) vertical p-n junctions which do not dope any other elements but only controls the oxygen content of GO. The I-V curve of the pGO vertical p-n junction demonstrates a remarkable rectification effect. In addition, the pGO vertical p-n junction shows stability of its rectification characteristic over long-term storage for six months when sealed and stored in a PE bag. Moreover, the pGO vertical p-n junctions have obvious photoelectric response and various rectification effects with different thicknesses and an oxygen content of GO, humidity, and temperature. Hall effect test results show that rGO is an n-type semiconductor; theoretical calculations and research show that GO is generally a p-type semiconductor with a bandgap, thereby forming a p-n junction. Our work provides a method for preparing undoped GO vertical p-n junctions with advantages such as simplicity, convenience, and large-scale industrial preparation. Our work demonstrates great potential for application in electronics and highly sensitive sensors.
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The transfer process of chemical vapor deposition graphene film leads to unavoidable crack, wrinkles, doping, and contamination, which limits its function to establish stable and high-performance devices. It raises a growing interest to fabricate high-quality graphene on the target substrate directly. Here, bi-layer graphene (BLG) film can be grown on sapphire substrate by a Cu sacrificial layer using atmospheric-pressure chemical vapor deposition. The as-obtained BLG at the interface between sapphire and Cu layer is free of wrinkles, and the corresponding surface roughness Ra is as low as 0.66 nm. The square resistance of the graphene is 898.1 ohm sq-1, which is the lowest among the records of graphene film directly grown on nonmetal substrates.
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BACKGROUND TheraSling therapy (TST) is a kind of rehabilitation therapy for patients with stroke in order to improving neural function. The aim of this study was to evaluate the clinical efficacy of TST combined with neuromuscular facilitation technique on hemiplegic gait in patients with stroke. MATERIAL AND METHODS Fifty-six patients with abnormal gait after stroke were recruited for this study and assigned randomly to either the control group (n=28) or the TST experiment group (n=28). Patients in the 2 groups all received neuromuscular facilitation technique treatment. In addition, patients in the TST experiment group were received TST. Treatments were 45 minutes a day for 6 weeks. RESULTS The functional ambulation category (FAC) score, improved Barthel index, Fugl-Meyer assessment (FMA), Berg balance scale (BBS), and 10 meters walking time and step length were significantly improve in both the TST experiment group and the control group after 6 weeks of treatment with a statistical difference (P<0.05). And the aforementioned indices in the TST experiment group after treatment were significantly higher than those of control group (P<0.05). CONCLUSIONS Lower extremity motor function and quality of life were significantly improved by TST combined with neuromuscular facilitation technique. However, the study had a small sample size, thus, further multicenter well-designed prospective randomized controlled trials are needed to confirm our findings.