Pattern-reconfigurable integrated array antenna based on a coding metasurface.

An electrically tunable pattern-reconfigurable integrated array antenna based on a 1-bit digital coding metasurface is proposed in this paper. The array antenna consists of 8 × 8 unit cells which is divided into the radiation antenna and the phase control metasurface. The rectangular microstrip patch antenna is used as the radiation source. The phase control metasurface includes three stacked layers of square slot units loaded with varactor diodes and a biasing circuit layer. The metasurface regulates the transmission phase of the quasi-plane wave generated by the radiation antenna. The pattern reconfigurability is achieved by switching coding sequences of the metasurface which can be regulated by the capacitance of varactor diodes. The measured results show the design has the capability of pencil-beam radiation, beam deflection, and multi-beam radiation at 5 GHz. The proposed array antenna preserves the coding metasurface without requiring the additional horn antenna. This highly integrated design is more concise and reduces the profile height. This article offers what we believe is a new method for the design of high integration, multi-unit, and electrically tunable reconfigurable array antenna.

The association between influenza vaccination, cardiovascular mortality and hospitalization: A living systematic review and prospective meta-analysis.

BACKGROUND: The effects of seasonal influenza vaccination on cardiovascular disease (CVD) outcomes, including among individuals with established CVD, are uncertain. METHODS: To evaluate the efficacy and safety of influenza vaccines compared to no vaccines or placebo for preventing all-cause/CVD mortality or all-cause/CVD hospitalization in the general population and in populations with pre-existing CVD, we conducted a living systematic review (LSR) and prospective meta-analysis (PMA). Published randomized controlled trials (RCT) and observational studies between 1994 and 2023 were searched. PRISMA guidelines were followed in the extraction of study details, and risk of bias was assessed using the Cochrane tools. Analyses were stratified by study design and CVD history. Study quality was evaluated using GRADE system. Meta analyses based on random-effects models were performed between July and October 2022. Pooled risk ratios (RRs) for all-cause/CVD mortality and all-cause/CVD hospitalization were main outcomes. RESULTS: Six published RCTs comprising 12,662 participants (mean age, 62 years; 45 % women; 8,797 with pre-existing CVD) and 37 observational studies comprising 6,311,703 participants (mean age, 49 years; 50 % women; 1,189,955 with pre-existing CVD) were included. Only those RCTs judged to be low risk were included in the analyses, and observational studies at anything greater than moderate risk of bias were excluded. In RCTs, influenza vaccine was not significantly associated with lower all-cause mortality (RR, 0.85; 95 %CI, 0.61-1.17), cardiovascular death (RR, 0.80; 95 %CI, 0.60-1.07), or CVD hospitalization (RR, 0.69; 95 %CI, 0.47-1.02). A statistically significant reduction in all-cause hospitalization (RR, 0.86; 95 %CI, 0.76-0.97) was observed. The evidence level was assessed as moderate for all-cause hospitalization, and low for other outcomes. Overall, observational studies suggested a stronger protective association between influenza vaccination and outcomes, except for CVD hospitalization. Based on RCTs, there was no difference in the effects of influenza vaccination on all-cause mortality among the general population compared to those with pre-existing CVD, although the summary point estimate favored benefits only in those with pre-existing CVD. CONCLUSIONS: While observational studies suggest that influenza vaccination may be associated with lower all-cause and CVD mortality and all-cause hospitalization, RCTs reported to date suggest a reduction in the risk of all-cause hospitalization but do not provide clear evidence to support preventive effects on mortality (all-cause or CVD) or CVD hospitalization.

Reconstruction of the Near-Field Electric Field by SNOM Measurement.

Scanning near-field optical microscope (SNOM) with nanoscale spatial resolution has been a powerful tool in studying the plasmonic properties of nano materials/structures. However, the quantification of the SNOM measurement remains a major challenge in the field due to the lack of reliable methodologies. We employed the point-dipole model to describe the tip-surface interaction upon laser illumination and theoretically derived the quantitative relationship between the measured results and the actual near-field electric field strength. Thus, we can experimentally reconstruct the near-field electric field through this theoretically calculated relationship. We also developed an experimental technique together with FEM simulation to get the above relationship experimentally and reconstruct the near-field electric field from the measurement by SNOM.

Cluster randomized trial of influenza vaccination in patients with acute heart failure in China: A mixed-methods feasibility study.

Uncertainties about the efficacy of influenza vaccination for populations with heart failure (HF) in preventing cardiovascular outcomes, as well as lack of effective vaccination strategies, may contribute to low vaccine coverage rate (VCR) in China and globally. We assessed the feasibility of a strategy to promote influenza vaccines in patients hospitalized with acute HF in China and to inform the design of a hybrid effectiveness-implementation cluster randomized trial to evaluate this strategy on mortality and hospital re-admission. We conducted a cluster randomized pilot trial involving 11 hospitals in Henan Province in China, with mixed-methods evaluation between December 2020 and April 2021. A process evaluation involved interviews with 51 key informants (patients, health professionals, policy makers). The intervention included education about influenza vaccination and availability of free vaccines administered prior to hospital discharge for HF patients, while usual care included attending community-based points of vaccination (PoV) for screening and vaccination. Implementation outcomes focused on reach, fidelity, adoption, and acceptability. Recruitment rates were assessed for trial feasibility. Effectiveness outcomes were influenza VCR, HF-specific rehospitalizations and mortality at 90 days. A total of 518 HF patients were recruited from 7 intervention and 4 usual care hospitals (mean of 45 participants per hospital per month). VCR was 89.9% (311/346, 86.1-92.8%) in the intervention group and 0.6% (1/172, 0.0-3.7%) in the control group. The process evaluation demonstrated reach to patients with lower socioeconomic and education status. There was good fidelity of the intervention components, with education and PoV set up processes being adapted to local hospital workflow and workforce capacity. Intervention was acceptable and adopted by patients and health professionals. However, outside of a trial setting, concerns were raised around vaccination reimbursement costs, workforce accountability and capacity. The intervention strategy appears feasible and acceptable for improving VCR in HF patients at county-level hospitals in China. Trial registration: This pilot trial is registered with the acronym PANDA II Pilot (Population Assessment of Influenza and Disease Activity) at ChiCTR.org.cn (ChiCTR2000039081).

Standing wave type localized surface plasmon resonance of multifold Ag nanorods.

Multifold Ag nanorods (AgNRs) have demonstrated great potentials in applications such as surface-enhanced Raman scattering technique due to their specially organized nanostructures. However, there is so far no systematic understanding of their localized surface plasmon resonance (LSPR) behaviors. This work comprehensively studied the plasmonic behaviors of AgNRs with 1, 2 and 3 folded arms. LSPR modes with charge oscillations resembling standing waves were excited in all nanostructures. As arm length increases, there were linear relationships between resonance wavelength and arm length, which applied to all LSPR modes studied. In addition, directly proportional relationships between the slopes of the linear functions and arm number were found for same order LSPR modes of AgNRs. For different modes of a specific AgNR, inversely proportional relationships between the slope and the resonance order N were discovered. These findings evidenced AgNR's standing wave type LSPR characteristics.

Fabrication and simulation of V-shaped Ag nanorods as high-performance SERS substrates.

Bending straight Ag nanorods (AgNRs) into V-shaped structures can generate a higher surface-enhanced Raman scattering (SERS) performance. Numerical simulations showed that V-shaped AgNRs with a total length between 300 nm and 800 nm were more sensitive than equal-length straight AgNRs under a 785 nm laser in most cases. It was found that at a laser wavelength between 500 nm and 1000 nm, the Raman enhancement factor (EF) of a V-shaped AgNR's 3rd plasmon mode was not only optimal among the other major plasmon modes, but also outperformed the plasmon modes of straight AgNRs. Besides, a linear relationship between the resonance wavelength of the V-shaped AgNR's 3rd mode and its length was observed both numerically and experimentally, which was beneficial for the optimization of SERS substrates. Under 785 nm laser excitation, V-shaped AgNR substrates with a single arm length between 330 nm and 340 nm possessed the highest SERS efficiency. This work took AgNR array substrates one step closer to practical applications.