Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The tra...Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The transformations proceed using Selectfluor and TEMPO as oxidants,either in the presence of catalytic amounts of Ag_(2)CO_(3)or in the absence of this catalyst.The methodology provides structurally diverse alduronic acid lactones and enables the preparation of rare sugar glyconolactones from easily available D-C-glycosides.Based on the^(18)O-labeling experiments,control experiments,and isolation of the key intermediates,a radical-polar crossover reaction mechanism is proposed.The utility of this method is demonstrated through efficient conversions of alduronic acid lactones into polyhydroxylated cyclic alkaloids and castanospermine-type architectures.展开更多
Local microcurrent monitoring is of great significance for biological and battery systems,yet it poses a formidable challenge.The current measurement techniques rely on electromagnetic materials which inevitably intro...Local microcurrent monitoring is of great significance for biological and battery systems,yet it poses a formidable challenge.The current measurement techniques rely on electromagnetic materials which inevitably introduce interference to the system under examination.To address this issue,a promising approach based on a dielectric fiberoptic sensor is demonstrated.The microfiber is capable of detecting microcurrent through monitoring the localized proton concentration signal with a pH resolution of 0.0052 pH units.By sensing the refractive index variation surrounding the sensor induced by the interaction between local proton concentration changes and oxidizer-treated microfiber surface through the evanescent field,this sensing mechanism effectively avoids the interference of the electromagnetic material on the performance of the tested system.This sensor exhibits a limit of detection for microcurrent of 1μA.The sensing region is a microfiber with a diameter of 8.8μm.It can get invaluable information that cannot be obtained through conventional electrochemical methods.Examples include photocurrent attenuation in photogenerated carrier materials during illumination,electrical activation in nerve cells,and fluctuations in the efficiency of electrical energy generation during battery discharge.This approach provides a powerful complement to electrochemical methods for the elucidation of microscale reaction mechanisms.The information provided by the prepared dielectric fiber-optic sensor will shed more light on proton kinetics and electrochemical and electrobiological mechanisms,which may fll an important gap in the current bioelectricity and battery monitoring methods.展开更多
The precise and rapid detection of micro-ribonucleic acid(microRNA)in the incipient stages of cancer can effectively elucidatethe pathogenesis,migration,and development of tumors.Most of the current microRNA detection...The precise and rapid detection of micro-ribonucleic acid(microRNA)in the incipient stages of cancer can effectively elucidatethe pathogenesis,migration,and development of tumors.Most of the current microRNA detection methods require largequantities of purified samples,labeling,extended incubation times,and cell lysis,leading to complex procedures that demandlabor-intensive preparations and stringent experimental conditions.In this work,we develop a portable and multifunctionalbiosensor based on an optical microfiber for the detection of microRNA in the early stages of cancer.An innovative grapheneoxide-supported bimetallic nanorod(GO-Au NR-Ag NR)interface is engineered on the surface of the optical microfiber toenhance sensor sensitivity for the early detection of ultralow concentrations of microRNA and to integrate cell lysis capabilities.With the enhancement of interface,the sensor is able to detect microRNA-21 at concentrations ranging from 10zmol/L to 0.1 nmol/L,with a limit of detection(LOD)of 0.25 amol/L.It is also capable of detecting microRNA-21 in bodyfluids,such as sweat and serum,with LODs of 0.5 amol/L and 0.9 amol/L,respectively.The nano-interface enables the useof photothermal effects by the microfiber to lyse cells and directly detect intracellular microRNA-21,significantly reducingsample extraction time and simplifying the extraction and detection process.This work provides a portable,ultrasensitive,compact,efficient,and non-invasive tool for point-of-care testing.展开更多
The resistance and immune evasion of methicillin-resistant Staphylococcus aureus(MRSA)in biofilms are the culprits behind persistent infections.There is an urgent need for safe and effective antibacterial strategies t...The resistance and immune evasion of methicillin-resistant Staphylococcus aureus(MRSA)in biofilms are the culprits behind persistent infections.There is an urgent need for safe and effective antibacterial strategies to address MRSA and biofilm-related infections.Herein,we propose the development of an allin-one optical microfiber that integrates rapid quantitative analysis with synergistic antimicrobial therapy for deep-seated MRSA in biofilms.The prepared interfacial-functionalized sensor can be used for quantitative analysis of MRSA in clinical whole-blood samples with low volumes(10μL),reducing the detection time to 30 min and effectively preventing false-positive and false-negative results.The sensor can also be used for multimode antimicrobial therapy.This one-time treatment accelerates recovery and prevents recurrence through the synergistic effect of photothermal therapy,photodynamic therapy,and the antibacterial effect of Ag^(+),as well as the activation of immune memory.The therapy is localized with relatively low hyperthermia and does not cause harm to the surrounding healthy tissues.The integration of therapeutic agents onto the optical microfiber precludes their enrichment in other organs.The light guided through the optical fiber can reach deep-seated biofilms,which other light sources fail to reach.This work is promising for the clinical diagnosis and treatment of deep-seated infections.展开更多
With the increasing penetration of wind power,using wind turbines to participate in the frequency regulation to support power system has become a clear consensus.To accurately quantify the inertia provided by the doub...With the increasing penetration of wind power,using wind turbines to participate in the frequency regulation to support power system has become a clear consensus.To accurately quantify the inertia provided by the doubly-fed induction generator(DFIG)based wind farm,the frequency response model of DFIG with additional frequency control is established,and then by using Routh approximation,the explicit expression of the virtual moment of inertia is derived for the DFIG gridconnected system.To further enhance the availability of the expression,an estimation method is proposed based on the matrix pencil method and the least squares algorithm for estimating the virtual moment of inertia provided by the wind farm.Finally,numerical results tested by a DFIG grid-connected system and a modified IEEE 30-bus system verify the derived expression of the virtual moment of inertia and the proposed estimation method.展开更多
To achieve the efficient application of impedance analysis in the stability assessment and enhancement of multiterminal DC distribution systems, this paper proposes the DCside reduced-order impedance models with power...To achieve the efficient application of impedance analysis in the stability assessment and enhancement of multiterminal DC distribution systems, this paper proposes the DCside reduced-order impedance models with power control and AC voltage control, respectively, by taking the load converter station as the object. By using the DC-side current as the feedforward state, the active compensator applied to the load converter station with two control modes is also derived as well as the corresponding reduced-order impedance models. Combined with the reduced-order impedance models, a method based on damping factor sensitivity is further proposed to design the parameters of the derived active compensators. The verification results in the frequency domain and time domain demonstrate the accuracy of the reduced-order impedance and the effectiveness of the proposed compensator parameter design method.展开更多
Optimal power flow(OPF) has been used for energy dispatching in active distribution networks.To satisfy constraints fully and achieve strict operational bounds under the uncertainties from loads and sources, this pape...Optimal power flow(OPF) has been used for energy dispatching in active distribution networks.To satisfy constraints fully and achieve strict operational bounds under the uncertainties from loads and sources, this paper derives an interval optimal power flow(I-OPF)method employing affine arithmetic and interval Taylor expansion.An enhanced I-OPF method based on successive linear approximation and second-order cone programming is developed to improve solution accuracy.The proposed methods are benchmarked against Monte Carlo simulation(MCS) and stochastic OPF.Tests on a modified IEEE 33-bus system and a real 113-bus distribution network validate the effectiveness and applicability of the proposed methods.展开更多
Obtaining detailed insight into the photocatalytic performance of heterogeneous photocatalytic materials,is important for evaluating material properties as well as guiding material design.However,capture of the detail...Obtaining detailed insight into the photocatalytic performance of heterogeneous photocatalytic materials,is important for evaluating material properties as well as guiding material design.However,capture of the detailed matter changes on a photocatalyst surface in real time,and in situ during photocatalysis remains challenging.This work reports a promising optical microfiber sensor integrating a photocatalytic reaction monolayer on an optical microfiber surface to monitor reaction kinetics using Cu_(2)O-based heterogeneous photocatalysts,as an example.The evanescent field of microfiber is used to track the photocatalytic process in real time,through the interaction with the catalytic layer,by monitoring the surface refractive index changes caused by adsorption and degradation.Since the catalytic layer is less than 1µm thick,the typical high-power light source can be replaced by low-power light irradiation.This method successfully reveals that relative to the pristine Cu_(2)O microspheres,the photocatalytic activity is enhanced by the incorporation of Ti_(3)C_(2)T_(x) MXene into Cu_(2)O,whereas incorporation of CdS into Cu_(2)O suppresses the activity.Compared with the existing methods used for photocatalysis evalu-ation,this optical microfiber can be directly employed in real matrices to track local photocatalytic performance.It can also provide details about the different adsorption/degradation kinetics of photocatalysts.It is suitable for most photocatalytic processes and is not limited to pollutants with characteristic UV–visible absorption spectra.This study provides important inspiration for the future development of in situ,real-time reaction assessment.展开更多
基金financial support from the Marine S&T Fund of Shandong Province for Qingdao Marine Science and Technology Center(No.2022QNLM030003-2)the National Key Research&Development Program of China(No.2022YFA2104902)the National Natural Science Foundation of China(Nos.21977088 and22377114)。
文摘Alduronic acid lactones and glyconolactones are highly functionalized and versatile chiral building blocks.Herein,we describe a novel approach to these compounds via decarboxylative oxygenation of uronic acids.The transformations proceed using Selectfluor and TEMPO as oxidants,either in the presence of catalytic amounts of Ag_(2)CO_(3)or in the absence of this catalyst.The methodology provides structurally diverse alduronic acid lactones and enables the preparation of rare sugar glyconolactones from easily available D-C-glycosides.Based on the^(18)O-labeling experiments,control experiments,and isolation of the key intermediates,a radical-polar crossover reaction mechanism is proposed.The utility of this method is demonstrated through efficient conversions of alduronic acid lactones into polyhydroxylated cyclic alkaloids and castanospermine-type architectures.
基金was supported by the National Natural Science Foundation of China(No.62375108)the Guangdong Basic and Applied Basic Research Foundation(No.2024A1515010088)+1 种基金the Guangzhou Science and Technology Plan Project(No.2023A03J0130)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2019BT02X105).
文摘Local microcurrent monitoring is of great significance for biological and battery systems,yet it poses a formidable challenge.The current measurement techniques rely on electromagnetic materials which inevitably introduce interference to the system under examination.To address this issue,a promising approach based on a dielectric fiberoptic sensor is demonstrated.The microfiber is capable of detecting microcurrent through monitoring the localized proton concentration signal with a pH resolution of 0.0052 pH units.By sensing the refractive index variation surrounding the sensor induced by the interaction between local proton concentration changes and oxidizer-treated microfiber surface through the evanescent field,this sensing mechanism effectively avoids the interference of the electromagnetic material on the performance of the tested system.This sensor exhibits a limit of detection for microcurrent of 1μA.The sensing region is a microfiber with a diameter of 8.8μm.It can get invaluable information that cannot be obtained through conventional electrochemical methods.Examples include photocurrent attenuation in photogenerated carrier materials during illumination,electrical activation in nerve cells,and fluctuations in the efficiency of electrical energy generation during battery discharge.This approach provides a powerful complement to electrochemical methods for the elucidation of microscale reaction mechanisms.The information provided by the prepared dielectric fiber-optic sensor will shed more light on proton kinetics and electrochemical and electrobiological mechanisms,which may fll an important gap in the current bioelectricity and battery monitoring methods.
基金the National Natural Science Foundation of China(No.62375108)the Guangzhou Science and Technology Plan Project(No.2023A03J0130)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2024A1515010088)the Local Innovative and Research Teams Project of the Guangdong Pearl River Talents Program(No.2019BT02X105)the Postdoctoral Fellowship Program(Grade B)of China Postdoctoral Science Foundation(No.GZB20230265)the National Innovation and Entrepreneurship Training Program For Undergraduate(No.S202410559087).
文摘The precise and rapid detection of micro-ribonucleic acid(microRNA)in the incipient stages of cancer can effectively elucidatethe pathogenesis,migration,and development of tumors.Most of the current microRNA detection methods require largequantities of purified samples,labeling,extended incubation times,and cell lysis,leading to complex procedures that demandlabor-intensive preparations and stringent experimental conditions.In this work,we develop a portable and multifunctionalbiosensor based on an optical microfiber for the detection of microRNA in the early stages of cancer.An innovative grapheneoxide-supported bimetallic nanorod(GO-Au NR-Ag NR)interface is engineered on the surface of the optical microfiber toenhance sensor sensitivity for the early detection of ultralow concentrations of microRNA and to integrate cell lysis capabilities.With the enhancement of interface,the sensor is able to detect microRNA-21 at concentrations ranging from 10zmol/L to 0.1 nmol/L,with a limit of detection(LOD)of 0.25 amol/L.It is also capable of detecting microRNA-21 in bodyfluids,such as sweat and serum,with LODs of 0.5 amol/L and 0.9 amol/L,respectively.The nano-interface enables the useof photothermal effects by the microfiber to lyse cells and directly detect intracellular microRNA-21,significantly reducingsample extraction time and simplifying the extraction and detection process.This work provides a portable,ultrasensitive,compact,efficient,and non-invasive tool for point-of-care testing.
基金supported by the National Natural Science Foundation of China(No.62375108)the Natural Science Foundation of Guangdong Province(No.2024A1515010088)+3 种基金the Guangzhou Science and Technology Plan Project(No.2023A03J0130)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2019BT02X105)the Science and Technology Project in Guangzhou(No.2024A03J0812)the Postdoctoral Fellowship Program(Grade B)of China Postdoctoral Science Foundation(No.GZB20230265).
文摘The resistance and immune evasion of methicillin-resistant Staphylococcus aureus(MRSA)in biofilms are the culprits behind persistent infections.There is an urgent need for safe and effective antibacterial strategies to address MRSA and biofilm-related infections.Herein,we propose the development of an allin-one optical microfiber that integrates rapid quantitative analysis with synergistic antimicrobial therapy for deep-seated MRSA in biofilms.The prepared interfacial-functionalized sensor can be used for quantitative analysis of MRSA in clinical whole-blood samples with low volumes(10μL),reducing the detection time to 30 min and effectively preventing false-positive and false-negative results.The sensor can also be used for multimode antimicrobial therapy.This one-time treatment accelerates recovery and prevents recurrence through the synergistic effect of photothermal therapy,photodynamic therapy,and the antibacterial effect of Ag^(+),as well as the activation of immune memory.The therapy is localized with relatively low hyperthermia and does not cause harm to the surrounding healthy tissues.The integration of therapeutic agents onto the optical microfiber precludes their enrichment in other organs.The light guided through the optical fiber can reach deep-seated biofilms,which other light sources fail to reach.This work is promising for the clinical diagnosis and treatment of deep-seated infections.
基金This work was supported in part by the National Science Foundation of China(No.51877015)the Science and Technology Foundation of State Grid Corporation of China(No.SGTYHT/19-JS-215).
文摘With the increasing penetration of wind power,using wind turbines to participate in the frequency regulation to support power system has become a clear consensus.To accurately quantify the inertia provided by the doubly-fed induction generator(DFIG)based wind farm,the frequency response model of DFIG with additional frequency control is established,and then by using Routh approximation,the explicit expression of the virtual moment of inertia is derived for the DFIG gridconnected system.To further enhance the availability of the expression,an estimation method is proposed based on the matrix pencil method and the least squares algorithm for estimating the virtual moment of inertia provided by the wind farm.Finally,numerical results tested by a DFIG grid-connected system and a modified IEEE 30-bus system verify the derived expression of the virtual moment of inertia and the proposed estimation method.
基金supported in part by the National Natural Science Foundation of China (No. 52007080)the China Postdoctoral Science Foundation (No.2020TQ0142)the Opening Foundation of State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources (No.LAPS21008)。
文摘To achieve the efficient application of impedance analysis in the stability assessment and enhancement of multiterminal DC distribution systems, this paper proposes the DCside reduced-order impedance models with power control and AC voltage control, respectively, by taking the load converter station as the object. By using the DC-side current as the feedforward state, the active compensator applied to the load converter station with two control modes is also derived as well as the corresponding reduced-order impedance models. Combined with the reduced-order impedance models, a method based on damping factor sensitivity is further proposed to design the parameters of the derived active compensators. The verification results in the frequency domain and time domain demonstrate the accuracy of the reduced-order impedance and the effectiveness of the proposed compensator parameter design method.
基金supported by Fundamental Research Funds for the Central Universities (No.2016XS02)National Natural Science Foundation of China (No.61772167)
文摘Optimal power flow(OPF) has been used for energy dispatching in active distribution networks.To satisfy constraints fully and achieve strict operational bounds under the uncertainties from loads and sources, this paper derives an interval optimal power flow(I-OPF)method employing affine arithmetic and interval Taylor expansion.An enhanced I-OPF method based on successive linear approximation and second-order cone programming is developed to improve solution accuracy.The proposed methods are benchmarked against Monte Carlo simulation(MCS) and stochastic OPF.Tests on a modified IEEE 33-bus system and a real 113-bus distribution network validate the effectiveness and applicability of the proposed methods.
基金Funding National Natural Science Foundation of China,51773084,Yunyun Huang,U1701268,Bai-Ou Guan,Natural Science Foundation of Guangdong Province,2019A1515011278,Yunyun Huang,Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program,2019BT02X105,Bai-Ou Guan,Special Funds for the Cultivation of Guangdong College Students'Scientific and Technological Innovation,pdjh2020a0061,Jiaxuan Liang,Undergraduate Innovation and Entrepreneurship Program,202010559050,Jiaxin Wan.
文摘Obtaining detailed insight into the photocatalytic performance of heterogeneous photocatalytic materials,is important for evaluating material properties as well as guiding material design.However,capture of the detailed matter changes on a photocatalyst surface in real time,and in situ during photocatalysis remains challenging.This work reports a promising optical microfiber sensor integrating a photocatalytic reaction monolayer on an optical microfiber surface to monitor reaction kinetics using Cu_(2)O-based heterogeneous photocatalysts,as an example.The evanescent field of microfiber is used to track the photocatalytic process in real time,through the interaction with the catalytic layer,by monitoring the surface refractive index changes caused by adsorption and degradation.Since the catalytic layer is less than 1µm thick,the typical high-power light source can be replaced by low-power light irradiation.This method successfully reveals that relative to the pristine Cu_(2)O microspheres,the photocatalytic activity is enhanced by the incorporation of Ti_(3)C_(2)T_(x) MXene into Cu_(2)O,whereas incorporation of CdS into Cu_(2)O suppresses the activity.Compared with the existing methods used for photocatalysis evalu-ation,this optical microfiber can be directly employed in real matrices to track local photocatalytic performance.It can also provide details about the different adsorption/degradation kinetics of photocatalysts.It is suitable for most photocatalytic processes and is not limited to pollutants with characteristic UV–visible absorption spectra.This study provides important inspiration for the future development of in situ,real-time reaction assessment.
