Haze (known as “Mai” 霾 in Chinese) threatens the health of billions of people across the globe. To begin solving this problem without severely slowing down the economy, one has to mechanistically and geographically...Haze (known as “Mai” 霾 in Chinese) threatens the health of billions of people across the globe. To begin solving this problem without severely slowing down the economy, one has to mechanistically and geographically pinpoint the sources of these pollutants, the key of which is to thoroughly characterize and fingerprint the particulates. Here we present a broad survey and classification of thousands of individual airborne particu-lates by using the Scanning Electron Microscope (SEM) to measure their diverse mor-phologies and chemistries, which could eventually be organized into a “haze finger-print database”. For instance, one collection in Xi’an City, China during March-April 2014 yielded 494 airborne particulates that settled on silicon wafers placed outside the window of a 3<sup>rd</sup> floor office. These 494 particulates were manually imaged with high resolution (down to 2 nm), elementally mapped using Energy-dispersive X-ray Spec-troscopy (EDS), and were identified and categorized into presumed source classes such as construction activities (Ca, Al, Si-O), coal burning (sulfates), biologic (pollen, bac-teria), automotive, mining, steel making, and etc. About 20% of the particulates have mysterious origins, as it is still unclear how they were formed, and a fraction of them contained clearly hazardous elements such as lead and chromium. For future work, we propose using unmanned aerial vehicles with a special “rolling film” substrate that can autonomously collect airborne particulates, a customized SEM auto-imaging system, and machine learning software to establish an online open-access database. The end goal would be to monitor and analyze the particulate pollutants that are pumped into our atmosphere every day, and precisely track down their sources so we can better model and police the quality of the air around us.展开更多
As a traditional Chinese medicine treatment,massage has significant clinical effect.In recent years,a large number of clinical studies have shown that the mechanism of massage in the treatment of diseases is related t...As a traditional Chinese medicine treatment,massage has significant clinical effect.In recent years,a large number of clinical studies have shown that the mechanism of massage in the treatment of diseases is related to the regulation of immune function.In this article,we review the existing problems and prospects of massage on children with diarrhea,asthma and recurrent respiratory tract infection in relation to its effect on the regulation of immune function.展开更多
A monolithic integrated ultraviolet-infrared(UV-IR) dual-color photodetector based on graphene/GaN heterojunction was fabricated by vertically integrating a GaN nanowire array on a silicon substrate with monolayer gra...A monolithic integrated ultraviolet-infrared(UV-IR) dual-color photodetector based on graphene/GaN heterojunction was fabricated by vertically integrating a GaN nanowire array on a silicon substrate with monolayer graphene. The device detects UV and IR lights by different mechanisms. The UV detection is accomplished by the forbidden band absorption of GaN, and the IR detection is realized by the free electron absorption of graphene. At peak wavelengths of 360 nm and 1540 nm, the detector has responsivities up to 6.93 A/W and 0.11 A/W, detection efficiencies of 1.23 × 1012 cm·Hz1/2·W-1 and 1.88 × 1010 cm·Hz1/2·W-1, respectively,and a short response time of less than 3 ms.展开更多
As a vitamin E isomer,δ-tocotrienol has attracted much attention owing to its rich biological activities for human health,especially anticancer activities.Microbial biosynthesis constitutes a promising strategy ofδ-...As a vitamin E isomer,δ-tocotrienol has attracted much attention owing to its rich biological activities for human health,especially anticancer activities.Microbial biosynthesis constitutes a promising strategy ofδ-tocotrienol production owing to its economic and environmental advantages.In this study,we employed modular engineering strategies to reconstruct and optimize a de novoδ-tocotrienol biosynthesis pathway in Saccharomyces cerevisiae.Subsequently,the rate-limiting steps were identified and eliminated and the key enzymes were assembled in theδ-tocotrienol biosynthesis module to develop a substrate channeling and improve their catalytic efficiency.Furthermore,the shikimate andδ-tocotrienol biosynthesis mod-ules were optimized via combination strategies to further increaseδ-tocotrienol production,following which theδ-tocotrienol titer reached 1455.5μg/L.Finally,overexpression of the endogenous transporter PDR11 and two-phase extraction fermenta-tion were employed forδ-tocotrienol production,yielding up to 3262.2μg/Lδ-tocotrienol.Thus,the findings of this study demonstrate the possibility of efficientδ-tocotrienol biosynthesis in S.cerevisiae.展开更多
文摘Haze (known as “Mai” 霾 in Chinese) threatens the health of billions of people across the globe. To begin solving this problem without severely slowing down the economy, one has to mechanistically and geographically pinpoint the sources of these pollutants, the key of which is to thoroughly characterize and fingerprint the particulates. Here we present a broad survey and classification of thousands of individual airborne particu-lates by using the Scanning Electron Microscope (SEM) to measure their diverse mor-phologies and chemistries, which could eventually be organized into a “haze finger-print database”. For instance, one collection in Xi’an City, China during March-April 2014 yielded 494 airborne particulates that settled on silicon wafers placed outside the window of a 3<sup>rd</sup> floor office. These 494 particulates were manually imaged with high resolution (down to 2 nm), elementally mapped using Energy-dispersive X-ray Spec-troscopy (EDS), and were identified and categorized into presumed source classes such as construction activities (Ca, Al, Si-O), coal burning (sulfates), biologic (pollen, bac-teria), automotive, mining, steel making, and etc. About 20% of the particulates have mysterious origins, as it is still unclear how they were formed, and a fraction of them contained clearly hazardous elements such as lead and chromium. For future work, we propose using unmanned aerial vehicles with a special “rolling film” substrate that can autonomously collect airborne particulates, a customized SEM auto-imaging system, and machine learning software to establish an online open-access database. The end goal would be to monitor and analyze the particulate pollutants that are pumped into our atmosphere every day, and precisely track down their sources so we can better model and police the quality of the air around us.
基金Department of Technology Social Development Project(2018SF-303)。
文摘As a traditional Chinese medicine treatment,massage has significant clinical effect.In recent years,a large number of clinical studies have shown that the mechanism of massage in the treatment of diseases is related to the regulation of immune function.In this article,we review the existing problems and prospects of massage on children with diarrhea,asthma and recurrent respiratory tract infection in relation to its effect on the regulation of immune function.
基金supported by the National Natural Science Foundation of China (Nos. 61574161 and 61574130)the Natural Science Foundation of Jiangsu Province,China (No. BK20180252)the Department of Science and Technology of Jilin Province,China(No. 20180520177JH)。
文摘A monolithic integrated ultraviolet-infrared(UV-IR) dual-color photodetector based on graphene/GaN heterojunction was fabricated by vertically integrating a GaN nanowire array on a silicon substrate with monolayer graphene. The device detects UV and IR lights by different mechanisms. The UV detection is accomplished by the forbidden band absorption of GaN, and the IR detection is realized by the free electron absorption of graphene. At peak wavelengths of 360 nm and 1540 nm, the detector has responsivities up to 6.93 A/W and 0.11 A/W, detection efficiencies of 1.23 × 1012 cm·Hz1/2·W-1 and 1.88 × 1010 cm·Hz1/2·W-1, respectively,and a short response time of less than 3 ms.
基金supported by the Key Research and Development Program of China(2022YFC2106100,2018YFA0900300)the National Natural Science Foundation of China(32021005)the Fundamental Research Funds for the Central Universities(JUSRP222007,JUSRP622004).
文摘As a vitamin E isomer,δ-tocotrienol has attracted much attention owing to its rich biological activities for human health,especially anticancer activities.Microbial biosynthesis constitutes a promising strategy ofδ-tocotrienol production owing to its economic and environmental advantages.In this study,we employed modular engineering strategies to reconstruct and optimize a de novoδ-tocotrienol biosynthesis pathway in Saccharomyces cerevisiae.Subsequently,the rate-limiting steps were identified and eliminated and the key enzymes were assembled in theδ-tocotrienol biosynthesis module to develop a substrate channeling and improve their catalytic efficiency.Furthermore,the shikimate andδ-tocotrienol biosynthesis mod-ules were optimized via combination strategies to further increaseδ-tocotrienol production,following which theδ-tocotrienol titer reached 1455.5μg/L.Finally,overexpression of the endogenous transporter PDR11 and two-phase extraction fermenta-tion were employed forδ-tocotrienol production,yielding up to 3262.2μg/Lδ-tocotrienol.Thus,the findings of this study demonstrate the possibility of efficientδ-tocotrienol biosynthesis in S.cerevisiae.
