Candida albicans is the most abundant fungal species in oral cavity. As a smart opportunistic pathogen, it increases the virulence byswitching its forms from yeasts to hyphae and becomes the major pathogenic agent for...Candida albicans is the most abundant fungal species in oral cavity. As a smart opportunistic pathogen, it increases the virulence byswitching its forms from yeasts to hyphae and becomes the major pathogenic agent for oral candidiasis. However, the overuse ofcurrent clinical antifungals and lack of new types of drugs highlight the challenges in the antifungal treatments because of the drugresistance and side effects. Anti-virulence strategy is proved as a practical way to develop new types of anti-infective drugs. Here,seven artemisinins, including artemisinin, dihydroartemisinin, artemisinic acid, dihydroartemisinic acid, artesunate, artemether andarteether, were employed to target at the hyphal development, the most important virulence factor of C. albicans. Artemisininsfailed to affect the growth, but significantly inhibited the hyphal development of C. albicans, including the clinical azole resistantisolates, and reduced their damage to oral epithelial cells, while arteether showed the strongest activities. The transcriptomesuggested that arteether could affect the energy metabolism of C. albicans. Seven artemisinins were then proved to significantlyinhibit the productions of ATP and cAMP, while reduced the hyphal inhibition on RAS1 overexpression strain indicating thatartemisinins regulated the Ras1-cAMP-Efg1 pathway to inhibit the hyphal development. Importantly, arteether significantlyinhibited the fungal burden and infections with no systemic toxicity in the murine oropharyngeal candidiasis models in vivo causedby both fluconazole sensitive and resistant strains. Our results for the first time indicated that artemisinins can be potentialantifungal compounds against C. albicans infections by targeting at its hyphal development.展开更多
Nanoparticle self-assembly is a vital research field with significant implications for fundamental science and a wide range of technological applications.This bottom-up approach enables the design and fabrication of m...Nanoparticle self-assembly is a vital research field with significant implications for fundamental science and a wide range of technological applications.This bottom-up approach enables the design and fabrication of mesoscopic materials with distinct electronic,magnetic,optical,mechanical,and catalytic properties.Monodisperse nanoparticles serve as fundamental building blocks for creating long-range ordered structures known as superlattices,superstructures,or supercrystals.Advances in wet chemical synthesis methods have provided access to a variety of nanoparticle shapes,sizes,and compositions,establishing a solid foundation for extensive studies in selfassembly.This review highlights the utility and advantages of various electron microscopy methods for characterizing the structures and dynamics of nanoparticle assemblies,ranging from conventional imaging and diffraction techniques to cuttingedge approaches such as electron tomography,focused ion beam scanning electron microscopy tomography,four-dimensional scanning transmission electron microscopy,and liquid cell transmission electron microscopy.These methods enable the acquisition of detailed two-dimensional and threedimensional structural information of nanoparticle superlattices in dry,frozen,and liquid states.We also highlight the development of advanced data processing algorithms and their implementation in open-source software packages to facilitate electron microscopy data analysis.By leveraging machine learning techniques,researchers can efficiently manage large and complex electron microscopy datasets and gain deeper insights into the mechanisms of nanoparticle selfassembly.We anticipate that the comprehensive electron microscopy toolkit,combined with advanced computational algorithms and machine learning,will continue to generate new knowledge and insights in nanoparticle self-assembly research.展开更多
We have carried out a comprehensive study on the formation mechanism of Au nanorods （AuNRs） in binary surfactant mixtures composed of quaternary ammonium halide and sodium oleate （NaOL）. We identify the cetyltrime...We have carried out a comprehensive study on the formation mechanism of Au nanorods （AuNRs） in binary surfactant mixtures composed of quaternary ammonium halide and sodium oleate （NaOL）. We identify the cetyltrimethyl ammonium （CTA）-Br-Ag^＋ complex as the key ingredient in directing the anisotropic growth of AuNRs. Based on the improved understanding of the cooperative interactions among CTA^＋, Br^- and Ag^＋, we further demonstrate that AgBr, which is readily solubilized by the cetyltrimethyl ammonium bromide （CTAB） or cetyltrimethyl ammonium chloride （CTAC） micelles, can be employed as the combined source of Ag^＋ and Br^- for the preparation of AuNRs. The growth of high-quality AuNRs can be completed within 15 min under extremely low bromide content （0.1 mM）.展开更多
Frequent start-stops of automatic seedling transplanters would lengthen the seedling picking time due to alternating movement of the motor,and cause positioning errors and frequent motor vibrations when starting the m...Frequent start-stops of automatic seedling transplanters would lengthen the seedling picking time due to alternating movement of the motor,and cause positioning errors and frequent motor vibrations when starting the machine.To solve these problems and ensure the pick-up continuity of automatic transplanters,in this study the smooth circular arc interpolation algorithm and the least square method for multinomial curve fitting were used to conduct the trajectory planning of automatic transplanter based on the movement of the pick-up arm of the transplanter.Velocity and time curves were fitted in segments to acquire motion control parameters and further tracking control was conducted.The mathematical model of the control system was established using Simulink,and simulation analysis and system debugging test were performed.Experiments show that the trajectory curves obtained by MATLAB’s data processing can realize the continual and smooth motion trajectory of the pick-up arm;stepper motor velocity control can effectively track the planning curve and improve the seedling pick-up efficiency.The pick-up and pushing time of each motion of the planned plug seedling transplanter reduced by 1.0678 s and the start-stop times reduced from 6 to 1,which solved the frequent motor vibrations when starting the machine and improved the stability of the system.In addition,overstep and out-of-step of the motor at the start-stop moment were avoided and displacement error was reduced.展开更多
基金the National Natural Science Foundation of China grants(81870778,82071106,82271033,81991500,81991501,82201046)Key Research and Development Projects of Science and Technology Department of Sichuan Province(2021YFQ0064)+1 种基金Technology Innovation R&D Project of Chengdu(2022-YF05-01401-SN)Applied Basic Research Programs of Sichuan Province(2020YJ0227).
文摘Candida albicans is the most abundant fungal species in oral cavity. As a smart opportunistic pathogen, it increases the virulence byswitching its forms from yeasts to hyphae and becomes the major pathogenic agent for oral candidiasis. However, the overuse ofcurrent clinical antifungals and lack of new types of drugs highlight the challenges in the antifungal treatments because of the drugresistance and side effects. Anti-virulence strategy is proved as a practical way to develop new types of anti-infective drugs. Here,seven artemisinins, including artemisinin, dihydroartemisinin, artemisinic acid, dihydroartemisinic acid, artesunate, artemether andarteether, were employed to target at the hyphal development, the most important virulence factor of C. albicans. Artemisininsfailed to affect the growth, but significantly inhibited the hyphal development of C. albicans, including the clinical azole resistantisolates, and reduced their damage to oral epithelial cells, while arteether showed the strongest activities. The transcriptomesuggested that arteether could affect the energy metabolism of C. albicans. Seven artemisinins were then proved to significantlyinhibit the productions of ATP and cAMP, while reduced the hyphal inhibition on RAS1 overexpression strain indicating thatartemisinins regulated the Ras1-cAMP-Efg1 pathway to inhibit the hyphal development. Importantly, arteether significantlyinhibited the fungal burden and infections with no systemic toxicity in the murine oropharyngeal candidiasis models in vivo causedby both fluconazole sensitive and resistant strains. Our results for the first time indicated that artemisinins can be potentialantifungal compounds against C. albicans infections by targeting at its hyphal development.
基金This work is supported by the National Science Foundation through grant no. DMR-1506460. We thank the Indiana University-Bloomington Nanoscale Characterization Facility for access to the scanning electron microscope, energy-dispersive X-ray spec- troscopy, thermal evaporator and atomic force microscope. We also thank the Electron Microscopy Center at Indiana University-Bloomington for the access to transmission electron microscopes. The XPSinstrument was supported by NSF award DMR MRI-1126394.
基金the support from the US National Science Foundation under awards DMR-2102526 and CBET-2223453.
文摘Nanoparticle self-assembly is a vital research field with significant implications for fundamental science and a wide range of technological applications.This bottom-up approach enables the design and fabrication of mesoscopic materials with distinct electronic,magnetic,optical,mechanical,and catalytic properties.Monodisperse nanoparticles serve as fundamental building blocks for creating long-range ordered structures known as superlattices,superstructures,or supercrystals.Advances in wet chemical synthesis methods have provided access to a variety of nanoparticle shapes,sizes,and compositions,establishing a solid foundation for extensive studies in selfassembly.This review highlights the utility and advantages of various electron microscopy methods for characterizing the structures and dynamics of nanoparticle assemblies,ranging from conventional imaging and diffraction techniques to cuttingedge approaches such as electron tomography,focused ion beam scanning electron microscopy tomography,four-dimensional scanning transmission electron microscopy,and liquid cell transmission electron microscopy.These methods enable the acquisition of detailed two-dimensional and threedimensional structural information of nanoparticle superlattices in dry,frozen,and liquid states.We also highlight the development of advanced data processing algorithms and their implementation in open-source software packages to facilitate electron microscopy data analysis.By leveraging machine learning techniques,researchers can efficiently manage large and complex electron microscopy datasets and gain deeper insights into the mechanisms of nanoparticle selfassembly.We anticipate that the comprehensive electron microscopy toolkit,combined with advanced computational algorithms and machine learning,will continue to generate new knowledge and insights in nanoparticle self-assembly research.
文摘We have carried out a comprehensive study on the formation mechanism of Au nanorods （AuNRs） in binary surfactant mixtures composed of quaternary ammonium halide and sodium oleate （NaOL）. We identify the cetyltrimethyl ammonium （CTA）-Br-Ag^＋ complex as the key ingredient in directing the anisotropic growth of AuNRs. Based on the improved understanding of the cooperative interactions among CTA^＋, Br^- and Ag^＋, we further demonstrate that AgBr, which is readily solubilized by the cetyltrimethyl ammonium bromide （CTAB） or cetyltrimethyl ammonium chloride （CTAC） micelles, can be employed as the combined source of Ag^＋ and Br^- for the preparation of AuNRs. The growth of high-quality AuNRs can be completed within 15 min under extremely low bromide content （0.1 mM）.
基金The research work was supported by the Project of National Natural Science Foundation of China(No.51565048)Excellent young teacher training program of Xinjiang Corps(CZ027213)Graduate Research and Innovation Project of Xinjiang Uygur Autonomous Region(XJGRI2017056)。
文摘Frequent start-stops of automatic seedling transplanters would lengthen the seedling picking time due to alternating movement of the motor,and cause positioning errors and frequent motor vibrations when starting the machine.To solve these problems and ensure the pick-up continuity of automatic transplanters,in this study the smooth circular arc interpolation algorithm and the least square method for multinomial curve fitting were used to conduct the trajectory planning of automatic transplanter based on the movement of the pick-up arm of the transplanter.Velocity and time curves were fitted in segments to acquire motion control parameters and further tracking control was conducted.The mathematical model of the control system was established using Simulink,and simulation analysis and system debugging test were performed.Experiments show that the trajectory curves obtained by MATLAB’s data processing can realize the continual and smooth motion trajectory of the pick-up arm;stepper motor velocity control can effectively track the planning curve and improve the seedling pick-up efficiency.The pick-up and pushing time of each motion of the planned plug seedling transplanter reduced by 1.0678 s and the start-stop times reduced from 6 to 1,which solved the frequent motor vibrations when starting the machine and improved the stability of the system.In addition,overstep and out-of-step of the motor at the start-stop moment were avoided and displacement error was reduced.
