Alexandrium blooms in the northwest area of the Bohai Sea(Qinhuangdao coastal area),China,produce large amounts of toxins that could be enriched in shellfish and consequently harm human bodies.To understand the succes...Alexandrium blooms in the northwest area of the Bohai Sea(Qinhuangdao coastal area),China,produce large amounts of toxins that could be enriched in shellfish and consequently harm human bodies.To understand the succession of the phytoplankton community structure during Alexandrium bloom events in the northwest area of the Bohai Sea off Qinhuangdao from April 2 to May 7,2019,microscopy observations and high-performance chromatography(HPLC)-pigment analysis were performed.Sixty species of phytoplankton were identified,mainly diatoms and dinofl agellates.The abundance of Alexandrium reached the maximum on April 16(3.3×10^(3) cells/L).HPLC-pigment CHEMTAX analysis showed that the phytoplankton community was composed mainly of diatoms,dinofl agellates,prasinophytes,and cryptophytes.Diatoms were the main contributor to the total Chl-a pool.There was a downward trend for the proportion of diatom biomass to the total Chl-a pool,followed by an upward trend.The proportion of dinoflagellate biomass showed the opposite trend,whereas that of the prasinophyte biomass presented an obvious increasing trend.Temperature,nutrients,and nutrient structures were the main factors on the distribution of different phytoplankton groups in the study area as shown in the redundancy analysis.This work illustrates the succession of phytoplankton community structures during Alexandrium blooms and provided a theoretical basis for studies on the mechanism underlying the outbreak of harmful algal blooms in sea areas.展开更多
Telomere length is a reliable biomarker for health and longevity prediction in both humans and animals.The common neuromodulation techniques,including deep brain stimulation(DBS)and optogenetics,have excellent spatial...Telomere length is a reliable biomarker for health and longevity prediction in both humans and animals.The common neuromodulation techniques,including deep brain stimulation(DBS)and optogenetics,have excellent spatial resolution and depth penetration but require implementation of electrodes or optical fibers.Therefore,it is important to develop methods for noninvasive modulation of telomere length.Herein,we reported on a new method for decelerating telomere shortening using noninvasive ultrasound deep brain stimulation(UDBS).Firstly,we found that UDBS could activate the telomerase-associated proteins in normal mice.Then,in the Alzheimer’s disease mice,UDBS was observed to decelerate telomere shortening of the cortex and myocardial tissue and to effectively improve spatial learning and memory abilities.Similarly,UDBS was found to significantly slow down telomere shortening of the cortex and peripheral blood,and improve motor and cognitive functions in aging mice.Finally,transcriptome analysis revealed that UDBS upregulated the neuroactive ligand-receptor interaction pathway.Overall,the present findings established the critical role of UDBS in delaying telomere shortening and indicated that ultrasound modulation of telomere length may constitute an effective therapeutic strategy for aging and aging-related diseases.展开更多
With the development of continuous-wave terahertz(THz) sources and array detectors, the pursuit of highfidelity real-time imaging is receiving significant attention within the THz community. Here, we report a real-tim...With the development of continuous-wave terahertz(THz) sources and array detectors, the pursuit of highfidelity real-time imaging is receiving significant attention within the THz community. Here, we report a real-time full-field THz phase imaging approach based on lensless Fourier-transform THz digital holography.A triangular interferometric layout is proposed based on an oblique illumination of 2.52 THz radiation, which is different from other lensless holographic configurations at other frequencies. A spherical reference beam is generated by a reflective parabolic mirror with minor propagation loss. The complex-valued images are reconstructed using a single inverse Fourier transform of the hologram without complex calculation of the diffraction propagation. The experimental result for a Siemens star validates the lateral resolution of-46 μm in the diagonal direction. Sub-pixel image registration and image stitching algorithms are applied to enlarge the area of the reconstructed images. The dehydration process of an aquatic plant leaf(Hottonia inflata) is monitored for the first time, to the best of our knowledge, at the THz band. Rapid variations in water content and morphology are measured with a time interval of 0.6 s and a total time of 5 min from a series of reconstructed amplitude and phase images, respectively. The proposed method has the potential to become a powerful tool to investigate spontaneous phenomena at the THz band.展开更多
Nitrogen(N)deposition has a profound influence on forest soil carbon(C)and N pools,but there was no consensus on the responses of different C and N components in different forest types.In this study,a two-year simulat...Nitrogen(N)deposition has a profound influence on forest soil carbon(C)and N pools,but there was no consensus on the responses of different C and N components in different forest types.In this study,a two-year simulated N deposition experiment with four levels of N(NH4NO3)-addition treatments(0,50,100,and 150 kg N/hm^(2)·a)were conducted in Larix gmelinii(LG)and Quercus mongolica(QM)plantation in Northeast China,in order to investigate the C and N pool dynamics under continuously enhanced N deposition.Soil organic carbon(SOC),soil total N(STN)and their active components(readily oxidizable C,ROC;dissolved organic C,DOC;microbial biomass C,MBC,dissolved organic N,DON;microbial biomass N,MBN)of the forest soil were measured monthly from May to October 2017.C and N contents in LG were observed higher than in QM.N addition had no effect on SOC and STN of LG,but significantly increased SOC and STN of QM at low N addition level.Low N addition generally raised active C components(ROC,DOC,and MBC)in both plantations,whereas high N addition did not significantly affect these components,or even decreased ROC in LG soil.Low N addition also increased STN and MBN of QM,while no significant change in STN and MBN of LG was observed.DON was directly affected by N addition and increased significantly with elevated N addition levels.The results indicated that N addition,especially of low rate,might enhance the C sequestration capacity of the forest soils and mitigate climate change.展开更多
Economic globalization has transformed many manufacturing enterprises from a single-plant production mode to a multi-plant cooperative production mode.The distributed flexible job-shop scheduling problem(DFJSP)has bec...Economic globalization has transformed many manufacturing enterprises from a single-plant production mode to a multi-plant cooperative production mode.The distributed flexible job-shop scheduling problem(DFJSP)has become a research hot topic in the field of scheduling because its production is closer to reality.The research of DFJSP is of great significance to the organization and management of actual production process.To solve the heterogeneous DFJSP with minimal completion time,a hybrid chemical reaction optimization(HCRO)algorithm is proposed in this paper.Firstly,a novel encoding-decoding method for flexible manufacturing unit(FMU)is designed.Secondly,half of initial populations are generated by scheduling rule.Combined with the new solution acceptance method of simulated annealing(SA)algorithm,an improved method of critical-FMU is designed to improve the global and local search ability of the algorithm.Finally,the elitist selection strategy and the orthogonal experimental method are introduced to the algorithm to improve the convergence speed and optimize the algorithm parameters.In the experimental part,the effectiveness of the simulated annealing algorithm and the critical-FMU refinement methods is firstly verified.Secondly,in the comparison with other existing algorithms,the proposed optimal scheduling algorithm is not only effective in homogeneous FMUs examples,but also superior to existing algorithms in heterogeneous FMUs arithmetic cases.展开更多
Massive usage scenarios prompt the prosperity of terahertz refractive index(THz RI) measurement methods.However, they are very difficult in measuring the full-field dynamical RI distributions of either solid samples w...Massive usage scenarios prompt the prosperity of terahertz refractive index(THz RI) measurement methods.However, they are very difficult in measuring the full-field dynamical RI distributions of either solid samples without a priori thickness or liquid samples. In this study, we propose total internal reflection THz digital holography and apply it for measuring RI distributions for both solid and liquid samples dynamically. An RI measurement model is established based on an attenuated total reflection prism with a pitching angle. The pitching angle and the field of view can be numerically calculated from the spectrogram of the off-axis Fresnel hologram,which solves the adjustment of the visually opaque prism irradiated by the invisible THz beam. Full-field RI distributions of the droplets of solid-state soy wax and distilled water are obtained and compared with THz time-domain spectroscopy. The evaporation of an ethanol solution droplet is recorded, and the variation of the RI distribution at the sample–prism interface is quantitatively visualized with a temporal resolution of 10 Hz. The proposed method greatly expands the sample range for THz RI measurements and provides unprecedented insight into investigating spontaneous and dynamic THz phenomena.展开更多
“Off-target effect”is one of the obstacles for targeted prodrugs in chemotherapy.To circumvent this issue,herein we propose a dual biomarker cascadeactivated prodrug strategy based on high levels of reactive oxygen ...“Off-target effect”is one of the obstacles for targeted prodrugs in chemotherapy.To circumvent this issue,herein we propose a dual biomarker cascadeactivated prodrug strategy based on high levels of reactive oxygen species(ROS)and tyrosinase(TYR)in melanoma cells.A representative prodrug,Coumarin-Quinazolinone-phenylBoronic acid pinacol ester(CQB),was prepared.The prodrug contained Coumarin-Quinazolinone(CQ)as mitochondria targeting and monitoring moiety and phenylboronic acid pinacol ester as a cascade-activated prowarhead.After activation by the endogenous ROS and subsequent TYR in melanoma cells,CQB can be converted to the final active reagent Coumarin-Quinazolinone-o-Quinone(CQQ)that contains o-quinone group as the reactive species.CQQ may interact with cellular nucleophiles to exert its genotoxic effect and disrupt the cellular redox balance.This enables CQB to selectively suppress melanoma.CQB accumulates in the mitochondria and causes mitochondrial dysfunction via affecting mitochondrial DNA integrity.This cascade-activated prodrug may provide a precise strategy for melanoma theranostics.展开更多
基金Supported by the Special Research for the Science and Technology Basic Resources Investigation Program of China(No.2018FY100200)the National Natural Science Foundation of China(Nos.31772075,32072329)the Project of Jiangsu Natural Science Foundation of China(No.BK20171262)。
文摘Alexandrium blooms in the northwest area of the Bohai Sea(Qinhuangdao coastal area),China,produce large amounts of toxins that could be enriched in shellfish and consequently harm human bodies.To understand the succession of the phytoplankton community structure during Alexandrium bloom events in the northwest area of the Bohai Sea off Qinhuangdao from April 2 to May 7,2019,microscopy observations and high-performance chromatography(HPLC)-pigment analysis were performed.Sixty species of phytoplankton were identified,mainly diatoms and dinofl agellates.The abundance of Alexandrium reached the maximum on April 16(3.3×10^(3) cells/L).HPLC-pigment CHEMTAX analysis showed that the phytoplankton community was composed mainly of diatoms,dinofl agellates,prasinophytes,and cryptophytes.Diatoms were the main contributor to the total Chl-a pool.There was a downward trend for the proportion of diatom biomass to the total Chl-a pool,followed by an upward trend.The proportion of dinoflagellate biomass showed the opposite trend,whereas that of the prasinophyte biomass presented an obvious increasing trend.Temperature,nutrients,and nutrient structures were the main factors on the distribution of different phytoplankton groups in the study area as shown in the redundancy analysis.This work illustrates the succession of phytoplankton community structures during Alexandrium blooms and provided a theoretical basis for studies on the mechanism underlying the outbreak of harmful algal blooms in sea areas.
基金supported by the National Natural Science Foundation of China(T2122023,12022410,12004410)Shenzhen Basic Science Research(JCYJ20200109105622824,JCYJ20200109110006136)+1 种基金the Natural Science Foundation of Fujian Province(2020J02063)the Xiamen Bureau of Science and Technology(3502Z20209005).
文摘Telomere length is a reliable biomarker for health and longevity prediction in both humans and animals.The common neuromodulation techniques,including deep brain stimulation(DBS)and optogenetics,have excellent spatial resolution and depth penetration but require implementation of electrodes or optical fibers.Therefore,it is important to develop methods for noninvasive modulation of telomere length.Herein,we reported on a new method for decelerating telomere shortening using noninvasive ultrasound deep brain stimulation(UDBS).Firstly,we found that UDBS could activate the telomerase-associated proteins in normal mice.Then,in the Alzheimer’s disease mice,UDBS was observed to decelerate telomere shortening of the cortex and myocardial tissue and to effectively improve spatial learning and memory abilities.Similarly,UDBS was found to significantly slow down telomere shortening of the cortex and peripheral blood,and improve motor and cognitive functions in aging mice.Finally,transcriptome analysis revealed that UDBS upregulated the neuroactive ligand-receptor interaction pathway.Overall,the present findings established the critical role of UDBS in delaying telomere shortening and indicated that ultrasound modulation of telomere length may constitute an effective therapeutic strategy for aging and aging-related diseases.
基金National Natural Science Foundation of China(62075001, 62175004)Beijing Municipal Commission of Education (KZ202010005008)。
文摘With the development of continuous-wave terahertz(THz) sources and array detectors, the pursuit of highfidelity real-time imaging is receiving significant attention within the THz community. Here, we report a real-time full-field THz phase imaging approach based on lensless Fourier-transform THz digital holography.A triangular interferometric layout is proposed based on an oblique illumination of 2.52 THz radiation, which is different from other lensless holographic configurations at other frequencies. A spherical reference beam is generated by a reflective parabolic mirror with minor propagation loss. The complex-valued images are reconstructed using a single inverse Fourier transform of the hologram without complex calculation of the diffraction propagation. The experimental result for a Siemens star validates the lateral resolution of-46 μm in the diagonal direction. Sub-pixel image registration and image stitching algorithms are applied to enlarge the area of the reconstructed images. The dehydration process of an aquatic plant leaf(Hottonia inflata) is monitored for the first time, to the best of our knowledge, at the THz band. Rapid variations in water content and morphology are measured with a time interval of 0.6 s and a total time of 5 min from a series of reconstructed amplitude and phase images, respectively. The proposed method has the potential to become a powerful tool to investigate spontaneous phenomena at the THz band.
基金This work was supported by the National Key Research and Development Program of China(grant No.2016YFD0200304,2017YFC0504205).
文摘Nitrogen(N)deposition has a profound influence on forest soil carbon(C)and N pools,but there was no consensus on the responses of different C and N components in different forest types.In this study,a two-year simulated N deposition experiment with four levels of N(NH4NO3)-addition treatments(0,50,100,and 150 kg N/hm^(2)·a)were conducted in Larix gmelinii(LG)and Quercus mongolica(QM)plantation in Northeast China,in order to investigate the C and N pool dynamics under continuously enhanced N deposition.Soil organic carbon(SOC),soil total N(STN)and their active components(readily oxidizable C,ROC;dissolved organic C,DOC;microbial biomass C,MBC,dissolved organic N,DON;microbial biomass N,MBN)of the forest soil were measured monthly from May to October 2017.C and N contents in LG were observed higher than in QM.N addition had no effect on SOC and STN of LG,but significantly increased SOC and STN of QM at low N addition level.Low N addition generally raised active C components(ROC,DOC,and MBC)in both plantations,whereas high N addition did not significantly affect these components,or even decreased ROC in LG soil.Low N addition also increased STN and MBN of QM,while no significant change in STN and MBN of LG was observed.DON was directly affected by N addition and increased significantly with elevated N addition levels.The results indicated that N addition,especially of low rate,might enhance the C sequestration capacity of the forest soils and mitigate climate change.
基金This work was supported by the National Natural Science Foundation of China(Nos.61973120,62076095,61673175,and 61573144).
文摘Economic globalization has transformed many manufacturing enterprises from a single-plant production mode to a multi-plant cooperative production mode.The distributed flexible job-shop scheduling problem(DFJSP)has become a research hot topic in the field of scheduling because its production is closer to reality.The research of DFJSP is of great significance to the organization and management of actual production process.To solve the heterogeneous DFJSP with minimal completion time,a hybrid chemical reaction optimization(HCRO)algorithm is proposed in this paper.Firstly,a novel encoding-decoding method for flexible manufacturing unit(FMU)is designed.Secondly,half of initial populations are generated by scheduling rule.Combined with the new solution acceptance method of simulated annealing(SA)algorithm,an improved method of critical-FMU is designed to improve the global and local search ability of the algorithm.Finally,the elitist selection strategy and the orthogonal experimental method are introduced to the algorithm to improve the convergence speed and optimize the algorithm parameters.In the experimental part,the effectiveness of the simulated annealing algorithm and the critical-FMU refinement methods is firstly verified.Secondly,in the comparison with other existing algorithms,the proposed optimal scheduling algorithm is not only effective in homogeneous FMUs examples,but also superior to existing algorithms in heterogeneous FMUs arithmetic cases.
基金National Natural Science Foundation of China(62075001, 62175004)Beijing Municipal Commission of Education (KZ202010005008)。
文摘Massive usage scenarios prompt the prosperity of terahertz refractive index(THz RI) measurement methods.However, they are very difficult in measuring the full-field dynamical RI distributions of either solid samples without a priori thickness or liquid samples. In this study, we propose total internal reflection THz digital holography and apply it for measuring RI distributions for both solid and liquid samples dynamically. An RI measurement model is established based on an attenuated total reflection prism with a pitching angle. The pitching angle and the field of view can be numerically calculated from the spectrogram of the off-axis Fresnel hologram,which solves the adjustment of the visually opaque prism irradiated by the invisible THz beam. Full-field RI distributions of the droplets of solid-state soy wax and distilled water are obtained and compared with THz time-domain spectroscopy. The evaporation of an ethanol solution droplet is recorded, and the variation of the RI distribution at the sample–prism interface is quantitatively visualized with a temporal resolution of 10 Hz. The proposed method greatly expands the sample range for THz RI measurements and provides unprecedented insight into investigating spontaneous and dynamic THz phenomena.
基金funded by the National Natural Science Foundation of China(nos.31871365 and 21708007)the Technology Innovation Program of Hunan Province(no.2018RS3060).
文摘“Off-target effect”is one of the obstacles for targeted prodrugs in chemotherapy.To circumvent this issue,herein we propose a dual biomarker cascadeactivated prodrug strategy based on high levels of reactive oxygen species(ROS)and tyrosinase(TYR)in melanoma cells.A representative prodrug,Coumarin-Quinazolinone-phenylBoronic acid pinacol ester(CQB),was prepared.The prodrug contained Coumarin-Quinazolinone(CQ)as mitochondria targeting and monitoring moiety and phenylboronic acid pinacol ester as a cascade-activated prowarhead.After activation by the endogenous ROS and subsequent TYR in melanoma cells,CQB can be converted to the final active reagent Coumarin-Quinazolinone-o-Quinone(CQQ)that contains o-quinone group as the reactive species.CQQ may interact with cellular nucleophiles to exert its genotoxic effect and disrupt the cellular redox balance.This enables CQB to selectively suppress melanoma.CQB accumulates in the mitochondria and causes mitochondrial dysfunction via affecting mitochondrial DNA integrity.This cascade-activated prodrug may provide a precise strategy for melanoma theranostics.
