<div style="text-align:justify;"> <span style="line-height:1.5;font-family:Verdana;"> <span style="font-family:"">C<span>arotenoids are isoprenoid pigments us...<div style="text-align:justify;"> <span style="line-height:1.5;font-family:Verdana;"> <span style="font-family:"">C<span>arotenoids are isoprenoid pigments used in food, chemical, text</span>ile, pharma<span>ceutical, and cosmetic industries. They act not only as </span>dyes and provitamins A but<span> also have antioxidants, photoprotective, anti</span>microbial properties, among others. This class of pigment can be obtained traditionally by plants or chemical synthesis, but they have some disadvantages. In recent years, search for alternative sources has been an important strategy for the carotenoid industries. Microbial synthesis is an alternative that has shown good yields, speed, <span>and reduced production costs. Hostile environments, such as the Caating</span>a dom<span>ain, represent an interesting source of microorganisms tha</span>t produce biomolecules, especially carotenoids, because of oxidative stress caused by sunlight. T<span>hus, this region has been attracting the attentio</span>n of the scientific community and industry for the use of these organisms in the production of carotenoids and applications in cosmetic products;since these compounds have interesti<span>ng antioxidant and photoprotective properties. In</span> this review, general characteristics of carotenoids, sources of production, industrial applicability, and commercialization will be discussed, as well as perspectives on the production of carotenoids from microorganisms isolated from the Caatinga and their application in anti-UV products.</span><span style="font-family:""></span> <p> <br /> </p> </span><span style="line-height:1.5;font-family:Verdana;"></span> </div> <span style="font-family:;" "=""></span>展开更多
The accurate and robust unmanned aerial vehicle(UAV)localization is significant due to the requirements of safety-critical monitoring and emergency wireless communication in hostile underground environments.Existing r...The accurate and robust unmanned aerial vehicle(UAV)localization is significant due to the requirements of safety-critical monitoring and emergency wireless communication in hostile underground environments.Existing range-based localization approaches fundamentally rely on the assumption that the environment is relatively ideal,which enables a precise range for localization.However,radio propagation in the underground environments may be dramatically influenced by various equipments,obstacles,and ambient noises.In this case,inaccurate range measurements and intermittent ranging failures inevitably occur,which leads to severe localization performance degradation.To address the challenges,a novel UAV localization scheme is proposed in this paper,which can effectively handle unreliable observations in hostile underground environments.We first propose an adaptive extended Kalman filter(EKF)based on the fusion of ultra-wideband(UWB)and inertial measurement unit(IMU)to detect and adjust the inaccurate range measurements.Aiming to deal with intermittent ranging failures,we further design the constraint condition by limiting the system state.Specifically,the auto-regressive model is proposed to implement the localization in the ranging blind areas by reconstructing the lost measurements.Finally,extensive simulations have been conducted to verify the effectiveness.We carry out field experiments in an underground garage and a coal mine based on P440 UWB sensors.Results show that the localization accuracy is improved by 16.9%compared with the recent methods in the hostile underground environments.展开更多
文摘<div style="text-align:justify;"> <span style="line-height:1.5;font-family:Verdana;"> <span style="font-family:"">C<span>arotenoids are isoprenoid pigments used in food, chemical, text</span>ile, pharma<span>ceutical, and cosmetic industries. They act not only as </span>dyes and provitamins A but<span> also have antioxidants, photoprotective, anti</span>microbial properties, among others. This class of pigment can be obtained traditionally by plants or chemical synthesis, but they have some disadvantages. In recent years, search for alternative sources has been an important strategy for the carotenoid industries. Microbial synthesis is an alternative that has shown good yields, speed, <span>and reduced production costs. Hostile environments, such as the Caating</span>a dom<span>ain, represent an interesting source of microorganisms tha</span>t produce biomolecules, especially carotenoids, because of oxidative stress caused by sunlight. T<span>hus, this region has been attracting the attentio</span>n of the scientific community and industry for the use of these organisms in the production of carotenoids and applications in cosmetic products;since these compounds have interesti<span>ng antioxidant and photoprotective properties. In</span> this review, general characteristics of carotenoids, sources of production, industrial applicability, and commercialization will be discussed, as well as perspectives on the production of carotenoids from microorganisms isolated from the Caatinga and their application in anti-UV products.</span><span style="font-family:""></span> <p> <br /> </p> </span><span style="line-height:1.5;font-family:Verdana;"></span> </div> <span style="font-family:;" "=""></span>
基金supported by the National Natural Science Foundation of China under Grant No.62272462the Natural Science Foundation of Jiangsu Province of China for Distinguished Young Scholars under Grant No.BK20230045the Shenzhen Science and Technology Program under Grant No.JCYJ20230807154300002.
文摘The accurate and robust unmanned aerial vehicle(UAV)localization is significant due to the requirements of safety-critical monitoring and emergency wireless communication in hostile underground environments.Existing range-based localization approaches fundamentally rely on the assumption that the environment is relatively ideal,which enables a precise range for localization.However,radio propagation in the underground environments may be dramatically influenced by various equipments,obstacles,and ambient noises.In this case,inaccurate range measurements and intermittent ranging failures inevitably occur,which leads to severe localization performance degradation.To address the challenges,a novel UAV localization scheme is proposed in this paper,which can effectively handle unreliable observations in hostile underground environments.We first propose an adaptive extended Kalman filter(EKF)based on the fusion of ultra-wideband(UWB)and inertial measurement unit(IMU)to detect and adjust the inaccurate range measurements.Aiming to deal with intermittent ranging failures,we further design the constraint condition by limiting the system state.Specifically,the auto-regressive model is proposed to implement the localization in the ranging blind areas by reconstructing the lost measurements.Finally,extensive simulations have been conducted to verify the effectiveness.We carry out field experiments in an underground garage and a coal mine based on P440 UWB sensors.Results show that the localization accuracy is improved by 16.9%compared with the recent methods in the hostile underground environments.
