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

Object Detection for Caries or Pit and Fissure Sealing Requirement in Children's First Permanent Molars

Dental caries is one of the most common oral diseases that, if left untreated, can lead to a variety of oral problems. It mainly occurs inside the pits and fissures on the occlusal/buccal/palatal surfaces of molars and children are a high-risk group for pit and fissure caries in permanent molars. Pit and fissure sealing is one of the most effective methods that is widely used in prevention of pit and fissure caries. However, current detection of pits and fissures or caries depends primarily on the experienced dentists, which ordinary parents do not have, and children may miss the remedial treatment without timely detection. To address this issue, we present a method to autodetect caries and pit and fissure sealing requirements using oral photos taken by smartphones. We use the YOLOv5 and YOLOX models and adopt a tiling strategy to reduce information loss during image pre-processing. The best result for YOLOXs model with tiling strategy is 72.3 mAP.5, while the best result without tiling strategy is 71.2. YOLOv5s6 model with/without tiling attains 70.9/67.9 mAP.5, respectively. We deploy the pre-trained network to mobile devices as a WeChat applet, allowing in-home detection by parents or children guardian

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

Ginseng Rb fraction protects glia, neurons and cognitive function in a rat model of neurodegeneration.

The loss and injury of neurons play an important role in the onset of various neurodegenerative diseases, while both microgliosis and astrocyte loss or dysfunction are significant causes of neuronal degeneration. Previous studies have suggested that an extract enriched panaxadiol saponins from ginseng has more neuroprotective potential than the total saponins of ginseng. The present study investigated whether a fraction of highly purified panaxadiol saponins (termed as Rb fraction) was protective for both glia and neurons, especially GABAergic interneurons, against kainic acid (KA)-induced excitotoxicity in rats. Rats received Rb fraction at 30 mg/kg (i.p.), 40 mg/kg (i.p. or saline followed 40 min later by an intracerebroventricular injection of KA. Acute hippocampal injury was determined at 48 h after KA, and impairment of hippocampus-dependent learning and memory as well as delayed neuronal injury was determined 16 to 21 days later. KA injection produced significant acute hippocampal injuries, including GAD67-positive GABAergic interneuron loss in CA1, paralbumin (PV)-positive GABAergic interneuron loss, pyramidal neuron degeneration and astrocyte damage accompanied with reactive microglia in both CA1 and CA3 regions of the hippocampus. There was also a delayed loss of GAD67-positive interneurons in CA1, CA3, hilus and dentate gyrus. Microgliosis also became more severe 21 days later. Accordingly, KA injection resulted in hippocampus-dependent spatial memory impairment. Interestingly, the pretreatment with Rb fraction at 30 or 40 mg/kg significantly protected the pyramidal neurons and GABAergic interneurons against KA-induced acute excitotoxicity and delayed injury. Rb fraction also prevented memory impairments and protected astrocytes from KA-induced acute excitotoxicity. Additionally, microglial activation, especially the delayed microgliosis, was inhibited by Rb fraction. Overall, this study demonstrated that Rb fraction protected both astrocytes and neurons, especially GABAergic interneurons, and maintained microglial homeostasis against KA-induced excitotoxicity. Therefore, Rb fraction has the potential to prevent and treat neurodegenerative diseases