Dear Editor,Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR)is a powerful and versatile gene editing system that has been extensively utilized in various animals and plants,which holds enormous potent...Dear Editor,Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR)is a powerful and versatile gene editing system that has been extensively utilized in various animals and plants,which holds enormous potential and value for scientific research and breeding.However,single-targeted CRISPR can only induce a few base deletions,insertions,or substitution.Ideally,thesemutations result in premature termination of the protein encoded by the target gene,leading to a loss of function[1].展开更多
The radical suppression of the photodarkening effect and laser performance deterioration via H2 loading were demonstrated in high-power Yb-doped fiber(YDF)amplifiers.The photodarkening loss at equilibrium was114.4 d B...The radical suppression of the photodarkening effect and laser performance deterioration via H2 loading were demonstrated in high-power Yb-doped fiber(YDF)amplifiers.The photodarkening loss at equilibrium was114.4 d B/m at 702 nm in the pristine fiber,while it vanished in the H2-loaded fiber.To obtain a deeper understanding of the impact of photodarkening on laser properties,the evolution of the mode instability threshold and output power in fiber amplifiers was investigated.After pumping for 300 min,the mode instability threshold of the pristine fiber dropped from 770 to 612 W,and the periodic fluctuation of the output power became intense,finally reaching 100 W.To address the detrimental effects originating from photodarkening,H2 loading was applied in contrast experiments.The output power remained stable,and no sign of mode instability was observed in the H2-loaded fiber.Moreover,the transmittance at 638 nm confirmed the absence of the photodarkening effect.The results pave the way for the further development of high-power fiber lasers.展开更多
Digital technologies are capable of facilitating and transforming tax administration and dispute resolution in various ways.This paper presents some existing and emerging best practices and suggests that there is an o...Digital technologies are capable of facilitating and transforming tax administration and dispute resolution in various ways.This paper presents some existing and emerging best practices and suggests that there is an opportunity for BRITACOM to take advantage of these technologies in enhancing tax dispute resolution among Belt and Road jurisdictions.展开更多
In this work, non-isothermal bleaching of Yb–Li co-doped fiber was investigated. The Yb–Li co-doped fiber was beneficial to reduce the photodarkening-induced excess loss and had no bad effect on the temperature of t...In this work, non-isothermal bleaching of Yb–Li co-doped fiber was investigated. The Yb–Li co-doped fiber was beneficial to reduce the photodarkening-induced excess loss and had no bad effect on the temperature of thermal bleaching(TB). Photodarkened fibers were bleached with different temperature ramp rates. The higher the ramp rate, the higher the complete bleaching temperature. The activation energy of the bleaching of Yb/Al/Li fiber was calculated by fitting, which was similar to that of an Yb-doped fiber. These observations are helpful in revealing the relationship between the mechanism of Li ion co-doping and TB.展开更多
1.The COVID-19 Pandemic The COVID-19 pandemic is killing hundreds of thousands of people and crippling businesses worldwide.2 There is no medical cure or vaccine yet.To prevent COVID-19 from crushing the health care s...1.The COVID-19 Pandemic The COVID-19 pandemic is killing hundreds of thousands of people and crippling businesses worldwide.2 There is no medical cure or vaccine yet.To prevent COVID-19 from crushing the health care system,non-essential activities have been paused and people are asked to stay home and keep"social distancing"in order to slow down the spread of the virus.展开更多
Platelet-rich plasma(PRP)that has various growth factors has been used clinically in cartilage repair.However,the short residence time and release time at the injury site limit its therapeutic effect.The present study...Platelet-rich plasma(PRP)that has various growth factors has been used clinically in cartilage repair.However,the short residence time and release time at the injury site limit its therapeutic effect.The present study fabricated a granular hydrogel that was assembled from gelatin microspheres and tannic acid through their abundant hydrogen bonding.Gelatin microspheres with the gelatin concentration of 10wt%and the diameter distribution of 1-10 lm were used to assemble by tannic acid to form the granular hydrogel,which exhibited elasticity under low shear strain,but flowability under higher shear strain.The viscosity decreased with the increase in shear rate.Meanwhile,the granular hydrogel exhibited self-healing feature during rheology test.Thus,granular hydrogel carrying PRP not only exhibited well-performed injectability but also performed like a‘plasticine’that possessed good plasticity.The granular hydrogel showed tissue adhesion ability and reactive oxygen species scavenging ability.Granular hydrogel carrying PRP transplanted to full-thickness articular cartilage defects could integrate well with native cartilage,resulting in newly formed cartilage articular fully filled in defects and well-integrated with the native cartilage and subchondral bone.The unique features of the present granular hydrogel,including injectability,plasticity,porous structure,tissue adhesion and reactive oxygen species scavenging provided an ideal PRP carrier toward cartilage tissue engineering.展开更多
Power scaling based on traditional ytterbium-doped fibers(YDFs)is limited by optical nonlinear effects and transverse mode instability(TMI)in high-power fiber lasers.Here,we propose a novel long tapered fiber with a c...Power scaling based on traditional ytterbium-doped fibers(YDFs)is limited by optical nonlinear effects and transverse mode instability(TMI)in high-power fiber lasers.Here,we propose a novel long tapered fiber with a constant cladding and tapered core(CCTC)along its axis direction.The tapered-core region of the fiber is designed to enhance the stimulated Raman scattering(SRS)threshold and suppress higher-order mode resonance in the laser cavity.The CCTC YDF was fabricated successfully with a modified chemical vapor deposition(MCVD)method combined with solution doping technology,which has a cladding diameter of 400µm and a varying core with a diameter of~24μm at both ends and~31μm in the middle.To test the performance of the CCTC fiber during high-power operation,an all-fiber laser oscillator based on a CCTC YDF was investigated experimentally.As a result,a maximum output power of 3.42 kW was achieved with an optical-to-optical efficiency of 55.2%,although the TMI effect was observed at an output power of~3.12 kW.The measured beam quality(M^(2)factor)was~1.7,and no sign of the Raman component was observed in the spectrum.We believe that CCTC YDF has great potential to simultaneously mitigate the SRS and TMI effects,and further power scaling is promising by optimizing the structure of the YDF.展开更多
Ytterbium-doped fibers have become the optimum gain media of high-power fiber lasers thanks to a simple energy structure, which strongly reduces the excited state absorption, and a low quantum defect and a high optic...Ytterbium-doped fibers have become the optimum gain media of high-power fiber lasers thanks to a simple energy structure, which strongly reduces the excited state absorption, and a low quantum defect and a high optic–optic conversion efficiency, which means the low thermal load. In this paper, we take a review of the current state of the art in terms of Yb^(3+)doped fibers for high-power fiber lasers, including the development of the fabrication techniques. The research work to overcome the challenges for Yb3+doped fibers, which affect the stability of output power and beam quality, will be demonstrated. Direction of further research is presented and the goal is to look for a fiber design, to boost single fiber output power, stabilize the laser power and support robust single-mode operation.展开更多
We demonstrate the fabrication of a novel magnetic nanohybrid involving the drug molecule 5 aminolevulinic acid(5-ALA)intercalated Gd-Eu layered rare-earth hydroxide(LRH)coated on magnesium ferrite particles(MgFe2O4)....We demonstrate the fabrication of a novel magnetic nanohybrid involving the drug molecule 5 aminolevulinic acid(5-ALA)intercalated Gd-Eu layered rare-earth hydroxide(LRH)coated on magnesium ferrite particles(MgFe2O4).The structure,thermostability,morphology,luminescence properties,cytotoxic effect and magnetism are investigated.The 5-ALA intercalated composite may correspond to a monolayered vertical arrangement,and the thermal stability of organics is enhanced after intercalation.The LRH precursor shows red emission of Eu^3+and the maximum emission peak of the composite is at 451 nm,corresponding to the blue emission.The detection of drug molecules can be realized through the change of luminescence.The magnetic nanohybrid shows strong magnetic sensitivity,which provides an easy and efficient way to separate 5-ALA-MgFe2O4@LGd0.95H:Eu0.05 particles from a sol or a suspension system and to carry drugs to targeted locations under an external magnetic field.The cytotoxic effect of MgFe2O4@LRH is observed with a sulforhodamine B(SRB)colorimetric assay,which has low cytotoxic effects on selected cells.The fabrication of novel bifunctional drug carriers based on LRH with magnetic and fluorescent properties has potential applications in drug detection and drug delivery.展开更多
The green-flesh(gf)mutant of the tomato fruit ripen to a muddy brown color and has been demonstrated previously to be a loss-of-function mutant.Here,we provide more evidence to support this view that S/SGR1 is involve...The green-flesh(gf)mutant of the tomato fruit ripen to a muddy brown color and has been demonstrated previously to be a loss-of-function mutant.Here,we provide more evidence to support this view that S/SGR1 is involved in color change in ripening tomato fruits.Knocking out SISGR1 expression using a clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9 genome editing strategy showed obviously a muddy brown color with significantly higher chlorophyll and carotenoid content compared with wild-type(WT)fruits.To further verify the role of SiSGR1 in fruit color change,we performed transcriptome deep sequencing(RNA-seq)analysis,where a total of 354 differentially expressed genes(124/230 downregulated/upregulated)were identified between WT and slsgr1.Additionally,the expression of numerous genes associated with photosynthesis and chloroplast function changed significantly when S/SGR1 was knocked out.Taken together,these results indicate that S/SGR1 is involved in color change in ripening fruit via chlorophyll degradation and carotenoid biosynthesis.展开更多
基金We thank Professor Pengcheng Wei of Anhui Agricultural University for his guidance on the experimental methods.This work was supported by the National Key Research and Development Program of China(Grant No.2022YFD2100101)the Joint NSFC-ISF Research Program(Grant No.32061143022)+1 种基金the 2115 Talent Development Program of China Agricultural University(Grant No.1061-00109017)to HZthe National Natural Science Foundation of China(Grant No.3217180159).
文摘Dear Editor,Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR)is a powerful and versatile gene editing system that has been extensively utilized in various animals and plants,which holds enormous potential and value for scientific research and breeding.However,single-targeted CRISPR can only induce a few base deletions,insertions,or substitution.Ideally,thesemutations result in premature termination of the protein encoded by the target gene,leading to a loss of function[1].
基金National Natural Science Foundation of China(61735007)National Key Research and Development Program of China(2017YFB1104400)。
文摘The radical suppression of the photodarkening effect and laser performance deterioration via H2 loading were demonstrated in high-power Yb-doped fiber(YDF)amplifiers.The photodarkening loss at equilibrium was114.4 d B/m at 702 nm in the pristine fiber,while it vanished in the H2-loaded fiber.To obtain a deeper understanding of the impact of photodarkening on laser properties,the evolution of the mode instability threshold and output power in fiber amplifiers was investigated.After pumping for 300 min,the mode instability threshold of the pristine fiber dropped from 770 to 612 W,and the periodic fluctuation of the output power became intense,finally reaching 100 W.To address the detrimental effects originating from photodarkening,H2 loading was applied in contrast experiments.The output power remained stable,and no sign of mode instability was observed in the H2-loaded fiber.Moreover,the transmittance at 638 nm confirmed the absence of the photodarkening effect.The results pave the way for the further development of high-power fiber lasers.
文摘Digital technologies are capable of facilitating and transforming tax administration and dispute resolution in various ways.This paper presents some existing and emerging best practices and suggests that there is an opportunity for BRITACOM to take advantage of these technologies in enhancing tax dispute resolution among Belt and Road jurisdictions.
基金supported by the National Key Research and Development Program of China(No.2017YFB1104400)the National Natural Science Foundation of China(No.61735007)
文摘In this work, non-isothermal bleaching of Yb–Li co-doped fiber was investigated. The Yb–Li co-doped fiber was beneficial to reduce the photodarkening-induced excess loss and had no bad effect on the temperature of thermal bleaching(TB). Photodarkened fibers were bleached with different temperature ramp rates. The higher the ramp rate, the higher the complete bleaching temperature. The activation energy of the bleaching of Yb/Al/Li fiber was calculated by fitting, which was similar to that of an Yb-doped fiber. These observations are helpful in revealing the relationship between the mechanism of Li ion co-doping and TB.
文摘1.The COVID-19 Pandemic The COVID-19 pandemic is killing hundreds of thousands of people and crippling businesses worldwide.2 There is no medical cure or vaccine yet.To prevent COVID-19 from crushing the health care system,non-essential activities have been paused and people are asked to stay home and keep"social distancing"in order to slow down the spread of the virus.
基金supported by the National Natural Science Foundation of China(Grant Nos 82272472,52373146,52173131,51973108)Natural Science Foundation of Shanghai(Grant No.22ZR1424700).
文摘Platelet-rich plasma(PRP)that has various growth factors has been used clinically in cartilage repair.However,the short residence time and release time at the injury site limit its therapeutic effect.The present study fabricated a granular hydrogel that was assembled from gelatin microspheres and tannic acid through their abundant hydrogen bonding.Gelatin microspheres with the gelatin concentration of 10wt%and the diameter distribution of 1-10 lm were used to assemble by tannic acid to form the granular hydrogel,which exhibited elasticity under low shear strain,but flowability under higher shear strain.The viscosity decreased with the increase in shear rate.Meanwhile,the granular hydrogel exhibited self-healing feature during rheology test.Thus,granular hydrogel carrying PRP not only exhibited well-performed injectability but also performed like a‘plasticine’that possessed good plasticity.The granular hydrogel showed tissue adhesion ability and reactive oxygen species scavenging ability.Granular hydrogel carrying PRP transplanted to full-thickness articular cartilage defects could integrate well with native cartilage,resulting in newly formed cartilage articular fully filled in defects and well-integrated with the native cartilage and subchondral bone.The unique features of the present granular hydrogel,including injectability,plasticity,porous structure,tissue adhesion and reactive oxygen species scavenging provided an ideal PRP carrier toward cartilage tissue engineering.
基金the National Natural Science Foundation of China(Nos.61735007 and 61705266).
文摘Power scaling based on traditional ytterbium-doped fibers(YDFs)is limited by optical nonlinear effects and transverse mode instability(TMI)in high-power fiber lasers.Here,we propose a novel long tapered fiber with a constant cladding and tapered core(CCTC)along its axis direction.The tapered-core region of the fiber is designed to enhance the stimulated Raman scattering(SRS)threshold and suppress higher-order mode resonance in the laser cavity.The CCTC YDF was fabricated successfully with a modified chemical vapor deposition(MCVD)method combined with solution doping technology,which has a cladding diameter of 400µm and a varying core with a diameter of~24μm at both ends and~31μm in the middle.To test the performance of the CCTC fiber during high-power operation,an all-fiber laser oscillator based on a CCTC YDF was investigated experimentally.As a result,a maximum output power of 3.42 kW was achieved with an optical-to-optical efficiency of 55.2%,although the TMI effect was observed at an output power of~3.12 kW.The measured beam quality(M^(2)factor)was~1.7,and no sign of the Raman component was observed in the spectrum.We believe that CCTC YDF has great potential to simultaneously mitigate the SRS and TMI effects,and further power scaling is promising by optimizing the structure of the YDF.
文摘Ytterbium-doped fibers have become the optimum gain media of high-power fiber lasers thanks to a simple energy structure, which strongly reduces the excited state absorption, and a low quantum defect and a high optic–optic conversion efficiency, which means the low thermal load. In this paper, we take a review of the current state of the art in terms of Yb^(3+)doped fibers for high-power fiber lasers, including the development of the fabrication techniques. The research work to overcome the challenges for Yb3+doped fibers, which affect the stability of output power and beam quality, will be demonstrated. Direction of further research is presented and the goal is to look for a fiber design, to boost single fiber output power, stabilize the laser power and support robust single-mode operation.
基金supported by the Youth Top-notch Talent Training Program for Universities and Colleges under Beijing Municipality(CIT&TCD201804035)the National Natural Science Foun-dation of China(Grant No.21601016)+1 种基金the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beiing Municipality(IDHT20180508)the Construc-tion of Scientific Research Platform(2018XK002).
文摘We demonstrate the fabrication of a novel magnetic nanohybrid involving the drug molecule 5 aminolevulinic acid(5-ALA)intercalated Gd-Eu layered rare-earth hydroxide(LRH)coated on magnesium ferrite particles(MgFe2O4).The structure,thermostability,morphology,luminescence properties,cytotoxic effect and magnetism are investigated.The 5-ALA intercalated composite may correspond to a monolayered vertical arrangement,and the thermal stability of organics is enhanced after intercalation.The LRH precursor shows red emission of Eu^3+and the maximum emission peak of the composite is at 451 nm,corresponding to the blue emission.The detection of drug molecules can be realized through the change of luminescence.The magnetic nanohybrid shows strong magnetic sensitivity,which provides an easy and efficient way to separate 5-ALA-MgFe2O4@LGd0.95H:Eu0.05 particles from a sol or a suspension system and to carry drugs to targeted locations under an external magnetic field.The cytotoxic effect of MgFe2O4@LRH is observed with a sulforhodamine B(SRB)colorimetric assay,which has low cytotoxic effects on selected cells.The fabrication of novel bifunctional drug carriers based on LRH with magnetic and fluorescent properties has potential applications in drug detection and drug delivery.
基金supported by the National Natural Science Foundation of China (No.31972472 and No.32061143022).
文摘The green-flesh(gf)mutant of the tomato fruit ripen to a muddy brown color and has been demonstrated previously to be a loss-of-function mutant.Here,we provide more evidence to support this view that S/SGR1 is involved in color change in ripening tomato fruits.Knocking out SISGR1 expression using a clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9 genome editing strategy showed obviously a muddy brown color with significantly higher chlorophyll and carotenoid content compared with wild-type(WT)fruits.To further verify the role of SiSGR1 in fruit color change,we performed transcriptome deep sequencing(RNA-seq)analysis,where a total of 354 differentially expressed genes(124/230 downregulated/upregulated)were identified between WT and slsgr1.Additionally,the expression of numerous genes associated with photosynthesis and chloroplast function changed significantly when S/SGR1 was knocked out.Taken together,these results indicate that S/SGR1 is involved in color change in ripening fruit via chlorophyll degradation and carotenoid biosynthesis.
