natural exposure
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2022 ◽  
Vol 2022 ◽  
pp. 1-12
Author(s):  
Baoqi Yan ◽  
Nuoya Zhang ◽  
Ganggang Lu ◽  
Yue Hui

We have completed the design of an early warning and evaluation analysis module based on machine learning algorithms. Aiming at the prestressed CFRP-strengthened reinforced concrete bridges under natural exposure, we developed a theoretical model to analyze the long-term prestress loss of reinforced parts and the adhesion behavior of the CFRP-concrete interface under natural exposure conditions. The analysis deeply reveals the technical and engineering geomechanics characteristics of the D bridge. At the same time, through a series of experimental studies on the D bridge condition monitoring system, the data acquisition and transmission, processing and control of the D bridge condition monitoring system, and the bridge condition monitoring and evaluation software are provided. Regarding how to repair the engineering geomechanical characteristics of D bridge, we mentioned the prestressed CFRP reinforcement technology. The prestressed carbon fiber reinforced composite (CFRP) structure made of reinforced concrete (RC) makes better use of the high-strength characteristics of CFRP and changes. It strengthens the stress distribution of the components and improves the overall strength of the components. It is more supported by engineers in the civil engineering and transportation departments. However, most prestressed CFRP-reinforced RC structures are located in natural exposure environments, and the effect of natural exposure environments on the long-term mechanical properties of prestressed C FRP-reinforced RC components is still unclear. This article mainly uses the research on the engineering geomechanics characteristics and reinforcement technology of the bridge body, so that people have a deep understanding of its concept, and provides reasonable use methods and measures for the maintenance and protection of the bridge body in the future. This paper studies the characteristics of engineering geomechanics based on machine learning algorithms and applies them to the research of CFRP reinforcement technology, aiming to promote its better development.


2021 ◽  
Author(s):  
Hideki Yoshioka ◽  
Yuhei Nishio ◽  
Manabu Kanematsu ◽  
Takafumi Noguchi ◽  
Tetsuya Hayakawa ◽  
...  

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Robert M. Mugo ◽  
Kennedy Mwai ◽  
Jedidah Mwacharo ◽  
Faiz M. Shee ◽  
Jennifer N. Musyoki ◽  
...  

Abstract Background RTS,S/AS01, the leading malaria vaccine has been recommended by the WHO for widespread immunization of children at risk. RTS,S/AS01-induced anti-CSP IgG antibodies are associated with the vaccine efficacy. Here, the long-term kinetics of RTS,S/AS01-induced antibodies was investigated. Methods 150 participants were randomly selected from the 447 children who participated in the RTS,S/AS01 phase IIb clinical trial in 2007 from Kilifi-Kenya. Cumulatively, the retrospective follow-up period was 93 months with annual plasma samples collection. The levels of anti-CSP IgM, total IgG, IgG1, IgG2, IgG3, and IgG4 antibodies were then determined using an enzyme-linked immunosorbent assay. Results RTS,S/AS01 induced high levels of anti-CSP IgG antibodies which exhibited a rapid waning over 6.5 months post-vaccination, followed by a slower decay over the subsequent years. RTS,S/AS01-induced anti-CSP IgG antibodies remained elevated above the control group levels throughout the 7 years follow-up period. The anti-CSP IgG antibodies were mostly IgG1, IgG3, IgG2, and to a lesser extent IgG4. IgG2 predominated in later timepoints. RTS,S/AS01 also induced high levels of anti-CSP IgM antibodies which increased above the control group levels by month 3. The controls exhibited increasing levels of the anti-CSP IgM antibodies which caught up with the RTS,S/AS01 vaccinees levels by month 21. In contrast, there were no measurable anti-CSP IgG antibodies among the controls. Conclusion RTS,S/AS01-induced anti-CSP IgG antibodies kinetics are consistent with long-lived but waning vaccine efficacy. Natural exposure induces anti-CSP IgM antibodies in children, which increases with age, but does not induce substantial levels of anti-CSP IgG antibodies.


2021 ◽  
Author(s):  
Thomas Clune ◽  
Amy Lockwood ◽  
Serina Hancock ◽  
Andrew N. Thompson ◽  
Mieghan Bruce ◽  
...  

Abstract Coxiella burnetii can cause reproductive disease in sheep and zoonotic Q-fever infections in humans. The role of infectious diseases including coxiellosis in causing poorer reproductive performance of primiparous ewes is not well studied. The aim of this study was to determine if natural exposure to C. burnetii is associated with poor reproductive performance of primiparous ewes and compare seroprevalence of primiparous and multiparous ewes. Coxiella burnetii seroprevalence was 0.08% (95% confidence interval 0.01, 0.36) in primiparous ewes and 0.36% (0.07, 1.14) in mature ewes. Coxiella burnetii was not detected in tissue samples from aborted or stillborn lambs using molecular diagnostic tests (qPCR). These findings suggest that C. burnetii infection was unlikely to be an important contributor to abortion and perinatal mortalities observed for primiparous ewes, and exposure to C. burnetii was not widespread in ewes on farms located over wide geographical region of southern Australia.


Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2688
Author(s):  
Mariaenrica Frigione ◽  
Alvaro Rodríguez-Prieto

During their useful life, polymers are subject to degradation processes due to exposure to specific environmental conditions over long times. These processes generally lead to changes, almost always irreversible, of properties and performances of polymers, changes which would be useful to be able to predict in advance. To meet this need, numerous investigations have been focused on the possibility to predict the long-term performance of polymers, if exposed to specific environments, by the so called “accelerated aging” tests. In such procedures, the long-term behavior of polymeric materials is typically predicted by subjecting them to cycles of radiations, temperatures, vapor condensation, and other external agents, at levels well above those found in true conditions in order to accelerate the degradation of polymers: this can produce effects that substantially deviate from those observable under natural exposure. Even following the standard codes, different environmental parameters are often used in the diverse studies, making it difficult to compare different investigations. The correlation of results from accelerated procedures with data collected after natural exposure is still a debated matter. Furthermore, since the environmental conditions are a function of the season and the geographical position, and are also characteristic of the type of exposure area, the environmental parameters to be used in accelerated aging tests should also consider these variables. These and other issues concerning accelerated aging tests applied to polymers are analyzed in the present work. However, bearing in mind the limitations of these practices, they can find useful applications for rating the durability of polymeric materials.


Author(s):  
Robert M. Ramirez ◽  
Robert Jacobs ◽  
Charles P Andrews

BACKGROUND: Oak and birch pollens are known to have strong cross-reactivity. It is unknown how robust this cross-reactivity is in subjects without natural exposure to pollen of both trees. We aimed to assess in an Allergen Challenge Chamber (ACC), the symptomatic responsiveness to birch pollen in subjects allergic to and naturally exposed to Virginia Live Oak (VLO) pollen and SPT-sensitive but not naturally exposed to birch pollen. METHODS: Subjects underwent SPT and blood draw for ssIgE to oak and birch antigens. Residential historical data were obtained. Subjects were exposed to birch pollen (3,500 ±700 gr/m ) in 2 consecutive 3-hour challenges. Symptoms were recorded at baseline and 30-minute intervals. RESULTS: Twenty-four subjects, 12 males, age 20-58 yrs, completed the study. Sixteen subjects (66.7%) responded with high total symptom scores (TSS) ≥10 of max 21. Twelve subjects (50%) had ssIgE ≥0.70 kU/L to oak. Subjects with a Class II ssIgE to oak pollen had a significantly higher max TSS than those without. Fifteen subjects without natural exposure to birch pollen responded with TSS equivalent to 9 with previous natural exposure. Those without natural birch exposure also responded similarly to subjects in birch endemic areas reported in the literature. CONCLUSION: Subjects allergic to oak pollen residing in South Texas, responded to birch pollen in an ACC with symptoms comparable to both those with previous exposure and also those residing in endemic areas and reported by other researchers. This robust response of cross-reactivity in oak-allergic subjects, without prior endemic exposure, suggests that a cross-reactive intervention could be efficacious.


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