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Graphene aerogels have implied great potential for electromagnetic wave absorption. However, the investigation of their design for broadband absorption in the terahertz (THz) range remains insufficient. Here, we propose an anisotropic honeycomb stack metamaterial (AHSM) based on graphene to achieve ultrawideband THz absorption. The absorption mechanism is elucidated using the effective medium method, offering deeper physics insights. At low THz frequencies, the impedance matching from the air to the AHSM can be improved by reducing the chemical potential of graphene for high absorption. There is a suppression of absorption at the intermediate frequencies due to constructive interference, which can be avoided by shortening the sizes of honeycomb edges. With the aim to elevate absorption at high frequencies, one can increase the stack layer number to enhance multiple reflections and destructive interference within the metastructure. Based on the above principles, we design an AHSM that achieves a broadband absorbance of over 90 % from 1 THz to 10 THz. This absorption can tolerate a wide range of incident angles for both TE and TM wave excitations. Our research will provide a theoretical guide to future experimental exploration of graphene aerogels for THz metamaterial absorber applications.

Bound state in the continuum (BIC), generally realized by structures with in-plane symmetry, has been under the spotlight in the control of the electromagnetic field. This Letter presents a terahertz metasurface that possesses broken in-plane symmetry for exciting BIC. The switch from a BIC to a quasi-BIC can be achieved through parameter modulation. According to multipolar decomposition, the BIC is constructed by the destructive interference of far-field radiation originating from the electric dipole and magnetic quadrupole. More importantly, considering that the metal material has finite conductivity, we analyze the relationship between radiation and non-radiation losses, based on the time domain coupled mode theory, which provides substantial theoretical support for the investigation of BIC phenomena. Furthermore, the proposed metasurface exciting quasi-BIC is highly sensitive to the changes in the dielectric environment, resulting in a high sensitivity of 135 GHz/RIU and a distinction between sucrose and glucose with the same solid content. As a result, our research provides a theoretical explanation of the evolution of BIC excited by the structure with broken in-plane symmetry and promotes the development of the high-performance meta-device used for sensing. [ABSTRACT FROM AUTHOR]

Background: Dementia care competence is defined as the ability, acquired through practical experience, to deliver high-quality care services to persons with dementia (PWD). However, many studies only focus on one aspect of competence using qualitative or quantitative research design and have small sample sizes of care staff with dementia. This study aims to conduct a mixed-methods systematic review of the factors influencing the competence of dementia care staff, and explore the relationship between these factors and competence. Methods: This review was designed following the PRISMA-P 2015 statement and methodological guidance for the conduct of mixed-methods systematic reviews from the Joanna Briggs Institute (JBI). Seven English and four Chinese databases will be searched to systematically review the existing eligible studies. JBI Critical Appraisal Checklist for Qualitative Research and Analytical Cross-Sectional Studies will be used to assess the methodological quality of each study. A JBI Mixed-Methods Data Extraction Form will be applied for data extraction. The JBI convergent integrated approach will be used for data synthesis and integration. The synthesized findings will be graded according to the JBI ConQual approach as high, moderate, low, or very low. The protocol was registered with PROSPERO in October 2023 (CRD42023474093). [ABSTRACT FROM AUTHOR]

A path-following control method based on dual heuristic programming (DHP) is proposed to address the problem whereby unmanned articulated vehicles need to set different controller parameters to track complex routes and cannot adapt to complex routes. First, the path-following control system structure is designed based on the articulated vehicle experimental platform, and the error model is derived based on the kinematic model of the articulated vehicle. Second, the payoff function is designed considering the error and stability indices, and the actor and critic of the path-following control method based on the DHP algorithm are approximated using a multilayer feedforward neural network. Finally, the path-following quality of the method is verified using simulations and real vehicle tests and compared with the conventional pure tracking and linear-quadratic regulator methods. The results show that the DHP-based method is able to follow complex reference paths and obtain better control results than the traditional methods without iterative tuning of the controller parameters, which improves the adaptiveness of the articulated vehicle path-following control method to complex environments. [ABSTRACT FROM AUTHOR]

Researchers have paid great attention to pursuing metal‐free nanostructures as alternatives to metallic counterparts in the field of surface‐enhanced Raman scattering (SERS) for label‐free sensing. However, these metal‐free investigations are hindered by the tiny enhancement factor of the local near field. Here, the design of all‐dielectric SERS metasurfaces is proposed with quasi‐bound states in the continuum (Q‐BIC), inspired by transformer‐based deep learning. By manipulating the incident angle, the mechanism of strong coupling Q‐BIC is introduced with a large Rabi splitting of ≈105 meV, which opens a bandgap and forms an anti‐crossing behavior. Compared to conventional approaches, the strong coupling Q‐BIC scheme not only boosts an extraordinary SERS enhancement factor of ≈107 but also extends the field‐enhancing scale up to ten‐fold. The theoretical optimization implies overwhelming dominance versus the conventional metallic nanostructure design for SERS. The study denotes an approach to utilize the strong coupling effects of Q‐BIC in all‐dielectric SERS metasurfaces and will provide essential design guides for more powerful sensing applications based on SERS. [ABSTRACT FROM AUTHOR]

Metformin has the potential for treating numerous diseases, but there are still many unrecognized and unreported adverse events (AEs). We selected data from the United States FDA Adverse Event Reporting System (FAERS) database from the first quarter (Q1) of 2004 to the fourth quarter (Q4) of 2022 for disproportionality analysis to assess the association between metformin and related adverse events. In this study 10,500,295 case reports were collected from the FAERS database, of which 56,674 adverse events related to metformin were reported. A total of 643 preferred terms (PTs) and 27 system organ classes (SOCs) that were significant disproportionality conforming to the four algorithms simultaneously were included. The SOCs included metabolic and nutritional disorders (p = 0.00E + 00), gastrointestinal disorders (p = 0.00E + 00) and others. PT levels were screened for adverse drug reaction (ADR) signals such as acute pancreatitis (p = 0.00E + 00), melas syndrome, pemphigoid (p = 0.00E + 00), skin eruption (p = 0.00E + 00) and drug exposure during pregnancy (p = 0.00E + 00). Most of our results were consistent with the specification, but some new signals of adverse reactions such as acute pancreatitis were not included. Therefore, further studies are needed to validate unlabeled adverse reactions and provide important support for clinical monitoring and risk identification of metformin. [ABSTRACT FROM AUTHOR]

Optical measurement of materials at the nanoscale is important for nanotechnology. Various plasmonic nanorulers have been studied for measuring nanoscale distance and orientation of materials, but they lack the capability to contain and measure nanoscale volumes, especially for liquid or soft materials. Here, we demonstrate the use of imprinted plasmonic volumetric nanocylinders, which act as nanoscale graduated cylinders and facilitate nanomaterial measurement via visible light. Our theoretical and experimental achievements illuminate a promising method for non-destructive, low-cost and fast measurement of material volume changes at the nanoscale, which will benefit the fields of analytical chemistry, nanofabrication and biomedical sensing.

Fine particulate matter (PM 2.5) samples were collected between November 2020 and October 2021 at the Minzu University of China in Beijing, and the n -alkyl nitrate concentrations in the PM 2.5 samples were determined to investigate n -alkyl nitrate pollution and formation mechanisms. C 9 –C 16 n -alkyl nitrate standards were synthesized, and the n -alkyl nitrate concentrations in PM 2.5 were determined by gas chromatography triple quadrupole mass spectrometry. Temporal trends in and correlations between particulate-bound n -alkyl nitrate, ozone, PM 2.5 , and nitrogen dioxide concentrations were investigated to assess the relationships between particulate-bound n -alkyl nitrate concentrations and gas-phase homogeneous reactions in the photochemical process and speculate the particulate-bound n -alkyl nitrates' formation mechanisms. The n -alkyl nitrate concentrations in the PM 2.5 samples were 9.67–2730 pg m -3 , and the mean was 578 pg m -3. The n -alkyl nitrate homologue group concentrations increased as the carbon chain length increased; i.e., long-chain n -alkyl nitrates contributed more than short-chain n -alkyl nitrates to the total n -alkyl nitrate concentrations in PM 2.5. The n -alkyl nitrate concentrations clearly varied seasonally and diurnally, the concentrations decreasing in the order winter > spring > autumn > summer and the mean concentrations being higher at night than in the day. The particulate-bound n -alkyl nitrate and ozone concentrations significantly negatively correlated despite gas-phase alkyl nitrate and ozone concentrations previously being found to positively correlate. This indicated that long-chain alkyl nitrates may not be produced during gas-phase homogeneous reactions. The particulate-bound n -alkyl nitrate concentrations followed the same trends as and significantly positively correlated with the PM 2.5 and nitrogen dioxide concentrations. Nitrogen dioxide is an important contributor of nitrates in particulate matter. This indicated that particulate-bound n -alkyl nitrates may form through non-homogeneous reactions between alkanes and nitrates on particulate matter surfaces. As secondary pollutants, particulate-bound alkyl nitrates are important components of PM 2.5 during haze events and strongly affect haze pollution and atmospheric visibility. [ABSTRACT FROM AUTHOR]

Plasmonic sensing has a great potential in the portable detection of human tumor markers, among which the carcinoembryonic antigen (CEA) is one of the most widely used in clinical medicine. Traditional plasmonic and non-plasmonic methods for CEA biosensing are still not suitable for the fast developing era of Internet of things. In this study, we build up a cost-effective plasmonic immunochip platform for rapid portable detection of CEA by combining soft nanoimprint lithography, microfluidics, antibody functionalization, and mobile fiber spectrometry. The plasmonic gold nanocave array enables stable surface functionality, high sensitivity, and simple reflective measuring configuration in the visible range. The rapid quantitative CEA sensing is implemented by a label-free scheme, and the detection capability for the concentration of less than 5 ng/ml is achieved in clinical experiments, which is much lower than the CEA cancer diagnosis threshold of 20 ng/ml and absolutely sufficient for medical applications. Clinical tests of the chip on detecting human serums demonstrate good agreement with conventional medical examinations and great advantages on simultaneous multichannel detections for high-throughput and multi-marker biosensing. Our platform provides promising opportunities on low-cost and compact medical devices and systems with rapid and sensitive tumor detection for point-of-care diagnosis and mobile healthcare.