Wideband hybrid metamaterial absorber via compound design of multiple mechanisms

Broadband and high efficiency are the two core indexes of absorption research, which usually requires a balance between them. Therefore, how to take into account both and achieve broadband and efficient absorption is a hot topic in current research. In this paper, by the compound design of multiple mechanisms, a kind of wideband hybrid metamaterial absorber (HMA) is proposed. The overall structure consists of a layer of patterned resistive film and a layer of magnetic absorbing material (MAM) separated by the air. The resistive layer is designed as square ring type to regulate the local magnetic field, which results in significant magnetic field enhancement within the MAM layer, and this mechanism provides a prerequisite for wideband and high-efficiency absorption in the low frequency band. Furthermore, due to the electrical losses of the resistive film, another absorption band is additionally excited in the high frequency band. Thanks to the multiple mechanisms, the absorption efficiency above 90% in the 3.2–22.0 GHz frequency band can be realized, and the thickness of the overall structure is 7.0 mm that is 0.07 of the wavelengths at the lowest frequency point. To demonstrate this method, a prototype is designed, fabricated and measured. Both the simulation and experiment results verify the effectiveness of the proposed method. This work provides a new method to design wideband and high-efficiency electromagnetic absorption structures and may find potential applications in multi-functional planar or conformal structures

Comparative transcriptomic and metabolomic analyses reveal differences in flavonoid biosynthesis between PCNA and PCA persimmon fruit

The fruit of the persimmon (Diospyros kaki.) has high economic and nutritional value and is rich in flavonoids. Flavonoids are essential secondary metabolisms in plants. The association between persimmon astringency and changes in the proanthocyanidins (a flavonoid subclass) content is well-known. However, information on the relationships between different astringency types and other flavonoid subclasses and biosynthetic genes is more limited. In this study, an initial correlation analysis between total flavonoids and fruit astringency type, and KEGG analysis of metabolites showed that flavonoid-related pathways were linked to differences between mature pollination-constant non-astringent (PCNA) varieties (‘Jiro’ and ‘Yohou’) and pollination-constant astringent (PCA) fruit varieties (‘Zhongshi5’ and ‘Huojing’). Based on these findings, variations in the expression of genes and metabolites associated with flavonoid biosynthesis were investigated between typical PCNA (‘Jiro’) and PCA (‘Huojing’) persimmons during fruit development. The flavonoid concentration in ‘Huojing’ fruit was significantly higher than that of ‘Jiro’ fruit, especially, in levels of proanthocyanin precursor epicatechin and anthocyanin cyanidin derivatives. Combined WGCNA and KEGG analyses showed that genes such as PAL, C4H, CHI, CHS, F3H, F3’5’H, FLS, DFR, ANR, ANS, and UF3GT in the phenylpropanoid and flavonoid biosynthesis pathways may be significant factors impacting the proanthocyanin precursor and anthocyanin contents. Moreover, interactions between the R2R3MYB (evm.TU.contig7272.598) and WD40 (evm.TU.contig3208.5) transcription factors were found to be associated with the above structural genes. These findings provide essential information on flavonoid biosynthesis and its regulation in the persimmon and lay a foundation for further investigation into how astringency types affect flavor components in PCNA and PCA persimmons

Association between occlusal support and cognitive impairment in older Chinese adults: a community-based study

IntroductionThe loss of occlusal support due to tooth loss is associated with systemic diseases. However, there was little about the association between occlusal support and cognitive impairment. The cross-sectional study aimed to investigate their association.MethodsCognitive function was assessed and diagnosed in 1,225 community-dwelling adults aged 60 years or older in Jing’an District, Shanghai. Participants were diagnosed with mild cognitive impairment (MCI) by Peterson’s criteria, or dementia, according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. We determined the number of functional occlusal supporting areas according to Eichner classifications. We used multivariate logistic regression models to analyze the relationship between occlusal support and cognitive impairment and mediation effect models to analyze the mediation effect of age.ResultsSix hundred sixty participants were diagnosed with cognitive impairment, averaging 79.92 years old. After adjusting age, sex, education level, cigarette smoking, alcohol drinking, cardiovascular disease, and diabetes, individuals with poor occlusal support had an OR of 3.674 (95%CI 1.141–11.829) for cognitive impairment compared to those with good occlusal support. Age mediated 66.53% of the association between the number of functional occlusal supporting areas and cognitive impairment.DiscussionIn this study, cognitive impairment was significantly associated with the number of missing teeth, functional occlusal areas, and Eichner classifications with older community residents. Occlusal support should be a significant concern for people with cognitive impairment

Sex differences in dementia risk and risk factors: Individual‐participant data analysis using 21 cohorts across six continents from the COSMIC consortium

Introduction: Sex differences in dementia risk, and risk factor (RF) associations with dementia, remain uncertain across diverse ethno‐regional groups. Methods: A total of 29,850 participants (58% women) from 21 cohorts across six continents were included in an individual participant data meta‐analysis. Sex‐specific hazard ratios (HRs), and women‐to‐men ratio of hazard ratios (RHRs) for associations between RFs and all‐cause dementia were derived from mixed‐effect Cox models. Results: Incident dementia occurred in 2089 (66% women) participants over 4.6 years (median). Women had higher dementia risk (HR, 1.12 [1.02, 1.23]) than men, particularly in low‐ and lower‐middle‐income economies. Associations between longer education and former alcohol use with dementia risk (RHR, 1.01 [1.00, 1.03] per year, and 0.55 [0.38, 0.79], respectively) were stronger for men than women; otherwise, there were no discernible sex differences in other RFs. Discussion: Dementia risk was higher in women than men, with possible variations by country‐level income settings, but most RFs appear to work similarly in women and men

Development and Evaluation of a Clinical Decision Support System for Central Venous Catheter Maintenance in the PICU

Objective To develop a Clinical Decision Support System(CDSS) for Central Venous Catheter (CVC) maintenance in a pediatric intensive care unit (PedN.CDSS-CVC); to evaluate the effect on adherence to Evidence-Based Practice(EBP), the quality of nursing documents and nurses’ perceived effectiveness with PedN.CDSS-CVC; and to explore the impact on Central Line-associated Bloodstream Infection(CLABSI) incidence outcomes. Methods The published literature was systematically searched, and literature types included guidelines, systematic reviews, evidence summaries, and best practice recommendations. Then, we extracted and summarized the evidence on CVC maintenance and established a CVC maintenance pediatric nursing knowledge base (PedN.KB-CVC) containing nursing diagnoses, nursing interventions and nursing outcomes. Clinical nursing experts who were familiar with pediatric intensive care, catheters maintenance and document review were invited to revise the PedN.KB-CVC, rendering the evidence more feasible and appropriate for the clinical workflow and regulations of the hospital. Clinical Care Classification (CCC) was used to code the revised PedN.KB-CVC. A multidisciplinary research team was established to design the PedN.CDSS-CVC function and interface. The design plan was delivered to engineers to perform the system development. The system provided decision-making support throughout the 5 steps of the CVC maintenance nursing process and generated structured document templates to ensure the homogenization and standardization of nursing documents. After the development was completed, a trial run of the PedN.CDSS-CVC was performed from November 1- 30, 2020, in the PICU of Children’s Hospital of Fudan University. During the trial run period, the PedN.CDSS-CVC was gradually improved and optimized according to the feedback from clinical nurses and began to be officially applied on December 1, 2020. A before-and-after study was conducted to examine the effect of CVC maintenance evidence-based practice compliance, the quality of nursing documents, and nurses’ perceived effectiveness with the PedN.CDSS- CVC. All of the above outcome measures from September 1 to October 31, 2020, were addressed as the control group, while those from December 1, 2020, to January 31, 2021, were addressed as the experimental group. We continually included maintenance cases and nursing documents in the two study periods. The Children's CVC Maintenance Evidence-based Practice Assessment Form was created as an instrument and used in on-site observation to explore the changes in EBP compliance; we used the Children's CVC Maintenance and Nursing Document Quality Assessment Form to evaluate the effectiveness regarding the quality of nursing documents and the Clinical Nursing Information System Effectiveness Evaluation Scale to evaluate user nurses’ experience before and after the PedN.CDSS-CVC was implemented. Finally, the incidence of central line-associated bloodstream infection (CLABSI) at the research site before and after the system application was compared over the study period. Results We constructed the PedN.KB-CVC, including 1 nursing diagnosis, 20 nursing interventions, and 3 nursing outcomes. A nursing process CDSS was then designed and optimized, and it could realize functions including automatic identification, automatic content pushing, template generation, automatic links, and warning/reminders. In the evaluation phase, 133 CVC maintenance cases and their nursing documents were included in the control group, while 116 were included in the experimental group. Among the 20 evidence- based practice assessment items, 12 were significantly improved after the system was applied (P<0.05). Regarding nursing document quality, the number of incomplete nursing documents decreased from 24 of 133 to 5 of 116, which was a significant difference (P<0.05). There were 17 of 133 inaccurate nursing documents in the control group and 12 of 116 in the experimental group, and there was no significant difference (P=0.55). Regarding the results of the nurses’ perceived effectiveness with the PedN.KB-CVC, 31 clinical nurses who performed the maintenance practice were included in both the control and experimental groups. The results of the Clinical Nursing Information System Effectiveness Evaluation Scale showed that significant improvement was found in completeness, continuity, reliability, empathy, improved service quality, improved work efficiency, reduced business costs, provided decision support, and improved service processes (P<0.05). However, over the study period, we did not find any significant difference in the CLABSI incidence at the research site (P=0.81). Conclusions The process of constructing a standardized knowledge base for children’s central venous care was scientific and rigorous and was conducive to the homogenization of nursing information. The system ensured a closed loop of the nursing process, improved EBP, improved the quality of nursing documents, and generally improved nurses’ experience with using the system. However, the results of this study cannot prove that the application of this system can reduce the incidence of CLABSI

Special Issue on Aerodynamic Noise Research of High-Speed Trains

Trains have gained immense popularity as a fast and efficient mode of transportation [...

Research Progress of Stress Measurement Technologies for Optical Elements

It is of great significance to measure the residual stress distribution accurately for optical elements and evaluate its influence on the performance of optical instruments in optical imaging, aviation remote sensing, semiconductor manufacturing, and other fields. The stress of optical elements can be closely related to birefringence based on photoelasticity. Thus, the method of quantifying birefringence to obtain the stress becomes the main method of stress measurement technologies for optical elements. This paper first introduces the basic principle of stress measurement based on photoelasticity. Then, the research progress of stress measurement technologies based on this principle is reviewed, which can be classified into two methods: polarization method and interference method. Meanwhile, the advantages and disadvantages of various stress measurement technologies are analyzed and compared. Finally, the developing trend of stress measurement technologies for optical elements is summarized and prospected

Robust optimisation of the streamlined shape of a high-speed train in crosswind conditions

Traditional deterministic aerodynamic optimisation cannot consider environmental uncertainty, which may lead to sensitivity issues. The present study proposes a robust design framework for the aerodynamic optimisation of high-speed trains, which accounts for the uncertain wind and its impact on crosswind stability. In this framework, a variance analysis method based on the Non-Intrusive Polynomial Chaos is proposed to determine the deformation area, and a parametric model is subsequently established. The Non-dominated Sorting Genetic Algorithm-II (NSGA-II) is used as the optimiser to minimise the mean and variance of the aerodynamic response. The mean and variance can be quickly predicted by an uncertainty analysis approach combining Monte Carlo simulation and Kriging model. The framework is then applied to the optimisation of a high-speed train under crosswind. The results of the robust optimisation are compared with those of the baseline geometry and deterministic optimisation. The mean and variance of the rolling moment under crosswind are reduced by 2.26% and 3.37% respectively after optimisation, indicating that the performance and robustness are both improved. The proposed framework is effective for the engineering design of high-speed trains and can also provide a reference for the robust design of other aerodynamic shapes