A traditional aircraft is optimized for only one or two flight conditions, not for the entire flight envelope. In contrast, the wings of a bird can be reshaped to provide optimal performance at all flight conditions. Any change in an aircraft’s configuration, in particular the wings, affects the aerodynamic performance, and optimal configurations can be obtained for each flight condition. Morphing technologies offer aerodynamic benefits for an aircraft over a wide range of flight conditions. The advantages of a morphing aircraft are based on an assumption that the additional weight of the morphing components is acceptable. Traditional mechanical and hydraulic systems are not considered good choices for morphing aircraft. “Smart” materials and structures have the advantages of high energy density, ease of control, variable stiffness, and the ability to tolerate large amounts of strain. These characteristics offer researchers and designers new possibilities for designing morphing aircraft. In this article, recent developments in the application of smart materials and structures to morphing aircraft are reviewed. Specifically, four categories of applications are discussed: actuators, sensors, controllers, and structures.
Background
Human papillomavirus (HPV) infection may lead to a series of lesions in the cervix. Distributions of HPV genotypes reveal that an increased prevalence of high-risk HPV (HR-HPV) is positively correlated with the severity of cervical lesions. Furthermore, persistent infection of HR-HPV is associated with a risk of cervical cancer. Considering the newly approval of the HPV vaccine in China and the prevalence of HPV distribution, which is meaningful for directing efforts for HPV vaccination, a more detailed understanding of HPV distribution is critical. This study aimed to investigate the overall prevalence of HPV and the age-specific features related to HPV distribution in the Jiangsu population.
Methods
We collected a total of 62,317 cervical cytological specimens from Xuzhou, Nanjing and Suzhou, which represent the northern, middle and southern regions of Jiangsu Province, respectively. All these samples were assigned to 6 groups based on participant age. HPV genotypes tests were performed by using a commercial kit which is designed for the detection of 17 high-risk HPV genotypes and 6 low-risk HPV genotypes.
Results
The overall prevalence of HPV was up to 26.92% in Jiangsu Province. The most common high-risk genotype was HPV52 (5.09%), followed by HPV16, HPV58, HPV53, HPV51 and HPV68. The most prevalent low-risk genotype was HPV81 (2.70%), followed by HPV43, HPV42, HPV6, HPV11 and HPV83. Most infections were caused by HR-HPV, while single-genotype infection occurred more frequently than multiple-genotype infection. Regarding participant age, the overall infection rate of HPV was distributed in a U-shaped manner, with the highest peak in the younger than 20-year-old cohort. Additionally, significant variations were found between different cities, representing different regions of Jiangsu.
Conclusions
HPV prevalence is high in Jiangsu Province. The prevention of HPV-related diseases is challenging. Given the variation in HPV prevalence between ages groups and regions, a flexible HPV vaccination program, adjusted base on regional infection features, could have a beneficial effect in Jiangsu Province.
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