Modeling, Simulation and Implementation of a Bird-Inspired Morphing Wing Aircraft

We present a design of a bird-inspired morphing wing aircraft, including bionic research, modeling, simulation and flight experiments. Inspired by birds and activated by a planar linkage, our proposed aircraft has three key states: gliding, descending and high-maneuverability. We build the aerodynamic model of the aircraft and analyze its mechanisms to find out a group of optimized parameters. Furthermore, we validate our design by Computational Fluid Dynamics (CFD) simulation based on Lattice-Boltzmann technology and determine three phases of the planar linkage for the three states. Lastly, we manufacture a prototype and conduct flight experiments to test the performance of the aircraft.Comment: 2019 3rd International Conference on Robotics and Automation Sciences (ICRAS

Synergistic heat treatment derived hollow-mesoporous-microporous Fe–N–C-SHT electrocatalyst for oxygen reduction reaction

© 2020 Exploring an economical and efficient oxygen reduction reaction (ORR) is an essential but challenging field of study. Metal–organic frameworks (MOFs) have emerged as promising candidates for the preparation of porous catalysts. Here we propose a synergistic heat treatment (SHT) method to synthesize Fe–N–C-SHT catalyst with hierarchical porous hollow structures via a simple carbonization method by the synergistic heating of ZIF-8-Fe (ZIF-8 doped with Fe) and ZIF-67 in a tube furnace. Fe–N–C-SHT catalyst displays efficient ORR activity (half-wave potential (Ehalf) = 0.88 V versus reversible hydrogen electrode (RHE) with a loading of 0.204 mgFe-N-C-SHTcm−2), which is superior to that of Fe–N–C synthesized using individual heat treatment (IHT) (Ehalf = 0.84 V) and Pt/C catalyst (Ehalf = 0.86 V). We achieve enhanced catalytic properties, enhanced methanol tolerance, and long-term durability of the Fe–N–C-SHT catalyst in alkaline electrolyte. The improved ORR activity is attributed to the synergistic effect of Fe doping and optimized SHT methodology, which led to the formation of a highly porous catalyst with numerous active sites. The developed SHT method presents a novel route to fabricate Fe–N–C catalysts with hollow-mesoporous-microporous structures and high performance in ORR

A Longitudinal Analysis about the Effect of Air Pollution on Astigmatism for Children and Young Adults

Purpose: This study aimed to investigate the correlation between air pollution and astigmatism, considering the detrimental effects of air pollution on respiratory, cardiovascular, and eye health. Methods: A longitudinal study was conducted with 127,709 individuals aged 4-27 years from 9 cities in Guangdong Province, China, spanning from 2019 to 2021. Astigmatism was measured using cylinder values. Multiple measurements were taken at intervals of at least 1 year. Various exposure windows were used to assess the lagged impacts of air pollution on astigmatism. A panel data model with random effects was constructed to analyze the relationship between pollutant exposure and astigmatism. Results: The study revealed significant associations between astigmatism and exposure to carbon monoxide (CO), nitrogen dioxide (NO2), and particulate matter (PM2.5) over time. A 10 {\mu}g/m3 increase in a 3-year exposure window of NO2 and PM2.5 was associated with a decrease in cylinder value of -0.045 diopters and -0.017 diopters, respectively. A 0.1 mg/m3 increase in CO concentration within a 2-year exposure window correlated with a decrease in cylinder value of -0.009 diopters. No significant relationships were found between PM10 exposure and astigmatism. Conclusion: This study concluded that greater exposure to NO2 and PM2.5 over longer periods aggravates astigmatism. The negative effect of CO on astigmatism peaks in the exposure window of 2 years prior to examination and diminishes afterward. No significant association was found between PM10 exposure and astigmatism, suggesting that gaseous and smaller particulate pollutants have easier access to human eyes, causing heterogeneous morphological changes to the eyeball

Impact of human papillomavirus vaccine on cervical cancer epidemic: Evidence from the surveillance, epidemiology, and end results program

IntroductionSince 2006, the human papillomavirus (HPV) vaccine has been recommended for females aged 9–26 years in the United States. Aiming to evaluate the early effect of the HPV vaccine on cervical cancer, this study assessed the incidence of cervical cancer by age and histology before and after the introduction of HPV vaccination.MethodsData on cervical cancer incidence from 1975–2019 were extracted from the Surveillance, Epidemiology, and End Results Program. Joinpoint regression was used to determine temporal trends over time. Future cervical cancer incidence (2015–2039) was projected using Bayesian age-period-cohort analysis. Age-period-cohort (APC) models were created to evaluate age, period, and cohort effects.ResultsFor overall cervical cancer and cervical squamous cell carcinoma (SCC), incidence rate showed decreasing trends (–0.7%, and –1.0% annually, respectively), whereas cervical adenocarcinoma (AC) incidence continuously increased (2.6% annually). The incidence trends for AC were stable in the 20–24 and 25–29-year age groups, whereas there was an increasing trend in older age groups. Similarly, the projected trend for AC in females aged 20–30 years exhibited a decline, whereas an increase was predicted in the 31–40–year age group, especially in the 35–44 year age group. The birth cohort and period effects in SCC and AC were extracted from APC models.DiscussionDuring the period of 1975–2019, the incidence of cervical AC remained almost unchanged in the age groups receiving HPV vaccines while increased in the age groups not receiving HPV vaccines. The birth cohort effects of SCC and AC of the cervix provided evidence supporting the effectiveness of the HPV vaccine in preventing cervical cancer

Effects of Aeration on Pollution Load and Greenhouse Gas Emissions from Agricultural Drainage Ditches

Human activities input a large amount of carbon and nitrogen nutrients into water, resulting in inland freshwater becoming an important source of greenhouse gas (GHG) emissions. Agricultural drainage ditches are the main transport route of non-point source pollution. Understanding the rules for how greenhouse gas emissions from drainage ditches impact the environment can help to accurately estimate the greenhouse effect of agricultural systems. However, current research mainly focuses on the effect of different measures on the migration and transformation process of pollutants in drainage ditches. The process of greenhouse gas emissions when the non-point source of pollution is transported by drainage ditches is still unclear. In this study, the influence of aeration on the pollution load and GHG emission process of a drainage ditch in a paddy field was explored. The following conclusions were drawn: Aeration reduced the content of nitrate nitrogen in the water but had no significant effect on the content of ammonium nitrogen and it reduced the chemical oxygen demand (COD) of water by 24.9%. Aeration increased the potential of hydrogen (PH), dissolved oxygen (DO) and oxidation–reduction potential (ORP) of water and reduced the total organic carbon content, microbial carbon content and soluble carbon content of the soil in the sediment. Aeration reduced the N2O and CH4 emission fluxes and increased the CO2 emission fluxes in the drainage ditch, but it reduced the greenhouse effect generated by the drainage ditch by 33.7%. This study shows that aeration can reduce both the pollution load and the greenhouse gas emission flux in drainage ditches

Testicular sperm aspiration has a poor effect in predicting micro-TESE outcomes in NOA patients with AZFc deletion

Abstract Background Testicular sperm aspiration (TESA) is widely used in the diagnosis and management of nonobstructive azoospermia. However, its ability for predicting microdissection testicular sperm extraction in nonobstructive azoospermia (NOA) patients with AZFc deletion remains uncertain. To investigate whether TESA affected the sperm retrieval rate (SRR) in NOA patients with AZFc deletion, a retrospective analysis of the clinical data of NOA patients with AZFc deletion who underwent microdissection testicular sperm extraction (micro-TESE) was conducted. The effects of age, testicular volume, follicle-stimulating hormone (FSH) levels, luteinizing hormone (LH) levels, testosterone (T) levels and TESA on the SRR were analyzed in this group of patients. Results A total of 181 individuals had their sperm successfully collected and underwent micro-TESE, with an SRR of 67.4%. The patients were separated into two groups based on their micro-TESE results (sperm acquisition and nonsperm acquisition), with no significant variations in age, testicular volume, FSH levels, LH levels, or T levels between the two groups. There was no significant difference in the SRR between any of the groups into which patients were classified based on reproductive hormone reference value ranges. Binary logistic regression was used to explore the absence of significant effects of age, testicular volume, FSH levels, LH levels, and T levels on sperm acquisition in patients undergoing micro-TESE. In the preoperative testicular diagnostic biopsy group, the sperm acquisition and nonsperm acquisition groups had SRRs of 90.1% and 65.1%, respectively. More significantly, there was no significant difference in the SRR between the negative preoperative testicular diagnostic biopsy group and the nonpreoperative testicular diagnostic biopsy group (65.1 vs. 63.8%, p = 0.855). Conclusion There is a high probability of successful sperm acquisition in the testis of men undergoing micro-TESE. In this group of patients, age, testicular volume, FSH levels, LH levels, and T levels may have little bearing on the micro-TESE outcome. In patients whose preoperative TESA revealed the absence of sperm, the probability of obtaining sperm by micro-TESE remained high (65.1%); negative TESA results appeared to not influence the SRR (63.8%) in patients undergoing micro-TESE