Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries.However,the sluggish reaction kinetics is a big obstacle for the developme...Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries.However,the sluggish reaction kinetics is a big obstacle for the development of high-performance sodium storage electrodes.Herein,we have rationally engineered the heterointerface by designing the Fe1?xS/MoS2 heterostructure with abundant“ion reservoir”to endow the electrode with excellent cycling stability and rate capability,which is proved by a series of in and ex situ electrochemical investigations.Density functional theory calculations further reveal that the heterointerface greatly decreases sodium ion diffusion barrier and facilitates charge-transfer kinetics.Our present findings not only provide a deep analysis on the correlation between the structure and performance,but also draw inspiration for rational heterointerface engineering toward the next-generation high-performance energy storage devices.展开更多
Targeted genome engineering refers to technologies that are used for site-specific genome modifications such as knockout, knockin and transcriptional regulation of genes of interest in organisms. Site-specific recombi...Targeted genome engineering refers to technologies that are used for site-specific genome modifications such as knockout, knockin and transcriptional regulation of genes of interest in organisms. Site-specific recombination system, zinc finger nucleases (ZFNs), transcriptional activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9) (CRISPR/Cas9) technologies are the representatives of targeted genome engineering and have been widely used in crop basic and applied research. In this review, we introduce the basic information and action modes of these different genome engineering technologies, summarize the recent progresses of targeted genome engineering technologies and their applications in crop improvement, and propose perspectives for genome engineering-mediated modifications of crop plants in the future.展开更多
In the ELMy H-mode experiment,naturally occurring dust originating at the high-field side is clearly observed using the high-speed vacuum ultraviolet imaging system developed on the Experimental Advanced Superconducti...In the ELMy H-mode experiment,naturally occurring dust originating at the high-field side is clearly observed using the high-speed vacuum ultraviolet imaging system developed on the Experimental Advanced Superconducting Tokamak(EAST).The main ablation cloud shape is similar to the classical shape observed in pellet fueling experiments.However,during the dust penetration,an erupted secondary cloudlet with a bent‘cigar’shape is observed and moves upwards along the direction perpendicular to the magnetic field line,which is different to the obviation in the pellet fueling experiments.This may be due to the ion diamagnetic drift effect.The velocities of the secondary cloudlet are estimated to be 50–80 m s^(-1).In addition,a significant degradation of the plasma confinement is observed during the dust penetration.展开更多
Monolayer group VI transition metal dichalcogenides(TMDs)have recently emerged as promising candidates for photonic and opto-valleytronic applications.The optoelectronic properties of these atomically-thin semiconduct...Monolayer group VI transition metal dichalcogenides(TMDs)have recently emerged as promising candidates for photonic and opto-valleytronic applications.The optoelectronic properties of these atomically-thin semiconducting crystals are strongly governed by the tightly bound electron-hole pairs such as excitons and trions(charged excitons).The anomalous spin and valley configurations at the conduction band edges in monolayer WS_(2)give rise to even more fascinating valley many-body complexes.Here we find that the indirect Q valley in the first Brillouin zone of monolayer WS_(2)plays a critical role in the formation of a new excitonic state,which has not been well studied.By employing a high-quality h-BN encapsulated WS_(2)field-effect transistor,we are able to switch the electron concentration within K-Q valleys at conduction band edges.Consequently,a distinct emission feature could be excited at the high electron doping region.Such feature has a competing population with the K valley trion,and experiences nonlinear power-law response and lifetime dynamics under doping.Our findings open up a new avenue for the study of valley many-body physics and quantum optics in semiconducting 2D materials,as well as provide a promising way of valley manipulation for next-generation entangled photonic devices.展开更多
An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and ...An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented.展开更多
A Ni Fe_2O_4/expanded graphite(Ni Fe_2O_4/EG)nanocomposite was prepared via a simple and inexpensive synthesis method. Its lithium storage properties were studied with the goal of applying it as an anode in a lithium-...A Ni Fe_2O_4/expanded graphite(Ni Fe_2O_4/EG)nanocomposite was prepared via a simple and inexpensive synthesis method. Its lithium storage properties were studied with the goal of applying it as an anode in a lithium-ion battery. The obtained nanocomposite exhibited a good cycle performance, with a capacity of 601 m Ah g^(-1)at a current of 1 A g^(-1)after 800 cycles. This good performance may beattributed to the enhanced electrical conductivity and layered structure of the EG. Its high mechanical strength could postpone the disintegration of the nanocomposite structure,efficiently accommodate volume changes in the Ni Fe_2O_4-based anodes, and alleviate aggregation of Ni Fe_2O_4 nanoparticles.展开更多
Single-or few-layer black phosphorus(FLBP)has attracted great attentions in scientic community with its excellent properties,including biodegradability,unique puckered lattice conguration,attractive electrical propert...Single-or few-layer black phosphorus(FLBP)has attracted great attentions in scientic community with its excellent properties,including biodegradability,unique puckered lattice conguration,attractive electrical properties and direct and tunable band gap.In recent years,FLBP has been widely studied in bio-photonicelds such as photothermal and photodynamic therapy,drug delivery,bioimaging and biosensor,showing attractive clinical potential.Because of the marked advantages of FLBP nanomaterials in bio-photonicelds,this review article reviews the latest advances of biomaterials based on FLBP in biomedical applications,ranging from biocompatibility,medical diagnosis to treatment.展开更多
AIM: To investigate the effects of our tumor vaccines on reversing immune tolerance and generating therapeutic response.METHODS: Vaccines were synthesized by solid phase using an Fmoc strategy,where a small molecule t...AIM: To investigate the effects of our tumor vaccines on reversing immune tolerance and generating therapeutic response.METHODS: Vaccines were synthesized by solid phase using an Fmoc strategy,where a small molecule toll-like receptor-7 agonist(T7) was conjugated to a monoclonal gastric cancer 7 antigen mono-epitope(T7-MG1) or tri-epitope(T7-MG3).Cytokines were measured in both mouse bone marrow dendritic cells and mouse spleen lymphocytes after exposed to the vaccines.BALB/c mice were intraperitoneally immunized with the vaccines every 2 wk for a total of three times,andthen subcutaneously challenged with Ehrlich ascites carcinoma(EAC) cells.Three weeks later,the mice were killed,and the tumors were surgically removed and weighed.Serum samples were collected from the mice,and antibody titers were determined by ELISA using an alkaline phosphate-conjugated detection antibody for total Ig G.Antibody-dependent cell-mediated cytotoxicity was detected by the lactate dehydrogenase method using natural killer cells as effectors and antibody-labeled EAC cells as targets.Cytotoxic T lymphocyte activities were also detected by the lactate dehydrogenase method using lymphocytes as effectors and EAC cells as targets.RESULTS: Vaccines were successfully synthesized and validated by analytical high performance liquid chromatography and electrospray mass spectrometry,including T7,T7-MG1,and T7-MG3.Rapid inductions of tumor necrosis factor-α and interleukin-12 in bone marrow dendritic cells and interferon γ and interleukin-12 in lymphocytes occurred in vitro after T7,T7-MG1,and T7-MG3 treatment.Immunization with T7-MG3 reduced the EAC tumor burden in BALB/c mice to 62.64% ± 5.55% compared with PBS control(P < 0.01).Six or nine weeks after the first immunization,the monoclonal gastric cancer 7 antigen antibody increased significantly in the T7-MG3 group compared with the PBS control(P < 0.01).As for antibody-dependent cell-mediated cytotoxicity,antisera obtained by immunization with T7-MG3 were able to markedly enhance cell lysis compared to PBS control(31.58% ± 2.94% vs 18.02% ± 2.26%; P < 0.01).As for cytotoxic T lymphocytes,T7-MG3 exhibited obviously greater cytotoxicity compared with PBS control(40.92% ± 4.38% vs 16.29% ± 1.90%; P < 0.01).CONCLUSION: A successful method is confirmed for the design of gastric cancer vaccines by chemical conjugation of T7 and multi-repeat-epitope of monoclonal gastric cancer 7 antigen.展开更多
We previously demonstrated that overexpression of tropomyosin receptor kinase A(TrkA)promotes the survival and Schwann celllike differentiation of bone marrow stromal stem cells in nerve grafts,thereby enhancing the r...We previously demonstrated that overexpression of tropomyosin receptor kinase A(TrkA)promotes the survival and Schwann celllike differentiation of bone marrow stromal stem cells in nerve grafts,thereby enhancing the regeneration and functional recovery of the peripheral nerve.In the present study,we investigated the molecular mechanisms underlying the neuroprotective effects of TrkA in bone marrow stromal stem cells seeded into nerve grafts.Bone marrow stromal stem cells from Sprague-Dawley rats were infected with recombinant lentivirus vector expressing rat TrkA,TrkA-shRNA or the respective control.The cells were then seeded into allogeneic rat acellular nerve allografts for bridging a 1-cm right sciatic nerve defect.Then,8 weeks after surgery,hematoxylin and eosin staining showed that compared with the control groups,the cells and fibers in the TrkA overexpressing group were more densely and uniformly arranged,whereas they were relatively sparse and arranged in a disordered manner in the TrkA-shRNA group.Western blot assay showed that compared with the control groups,the TrkA overexpressing group had higher expression of the myelin marker,myelin basic protein and the axonal marker neurofilament 200.The TrkA overexpressing group also had higher levels of various signaling molecules,including TrkA,pTrkA(Tyr490),extracellular signal-regulated kinases 1/2(Erkl/2),pErk1/2(Thr202/Tyr204),and the anti-apoptotic proteins Bcl-2 and Bcl-xL.In contrast,these proteins were downregulated,while the pro-apoptotic factors Bax and Bad were upregulated,in the TrkA-shRNA group.The levels of the TrkA effectors Akt and pAkt(Ser473)were not different among the groups.These results suggest that TrkA enhances the survival and regenerative capacity of bone marrow stromal stem cells through upregulation of the Erk/Bcl-2 pathway.All procedures were approved by the Animal Ethical and Welfare Committee of Shenzhen University,China in December 2014(approval No.AEWC-2014-001219).展开更多
In our previous study, metals have been used as absorbers in the clear plastic laser transmission welding. The effects of metal thermal conductivity on the welding quality are investigated in the present work. Four me...In our previous study, metals have been used as absorbers in the clear plastic laser transmission welding. The effects of metal thermal conductivity on the welding quality are investigated in the present work. Four metals with distinctly different thermal conductivities, i.e., titanium, nickel, molybdenum, and copper, are selected as light absorbers. The lap welding is conducted with an 808 nm diode laser and simulation experiments are also conducted. Nickel electroplating test is carried out to minimize the side-effects from different light absorptivities of different metals. The results show that the welding with an absorber of higher thermal conductivity can accommodate higher laser input power before smoking, which produces a wider and stronger welding seam.The positive role of the higher thermal conductivity can be attributed to the fact that a desirable thermal field distribution for the molecular diffusion and entanglement is produced from the case with a high thermal conductivity.展开更多
WRKY transcription factors are involved in defense responses caused by biotic stresses.Phylloxera(Daktulosphaira vitifoliae Fitch),a pest widespread in viticulture,elicits transcriptional reprogramming of plant defens...WRKY transcription factors are involved in defense responses caused by biotic stresses.Phylloxera(Daktulosphaira vitifoliae Fitch),a pest widespread in viticulture,elicits transcriptional reprogramming of plant defense-associated components,such as regulons related to WRKYs and salicylic acid(SA)signaling.In this study,we characterized WRKY46,a WRKY transcription factor responsible for phylloxera attack,and revealed the molecular mechanism for WRKY-mediated defense responses to phylloxera.qRT-PCR and GUS staining analyses revealed that WRKY46 is induced in response to phylloxera damage and mechanical wounding.VvWRKY46 is a nuclear-localized transcription factor that activates its downstream target VvCHIB by direct protein–DNA interaction.Regulons involved in the SA-mediated defense response were regulated during incompatible interactions between“1103 Paulsen”rootstock and phylloxera.In addition,WRKY46 exhibited a higher transcript abundance in“1103 Paulsen”than in“Crimson Seedless”,regardless of whether the plants were infected with phylloxera.Furthermore,the enhanced expression of VvWRKY46 significantly attenuated phylloxera attack and delayed nymph development of composite grape plants.In summary,we demonstrated that WRKY46 plays a role in the SA-mediated defense-regulatory network by directly binding to the downstream structural gene VvCHIB.The phylloxera-responsive gene WRKY46 was identified,which could improve the understanding of the basic mechanism of grapevine in response to phylloxera.展开更多
The design, fabrication and performance of narrow-band rugate minus filters are investigated in this paper. A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O2) and high(Al2...The design, fabrication and performance of narrow-band rugate minus filters are investigated in this paper. A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O2) and high(Al2 O3) refractive index materials is presented to fabricate a rugate structure. The narrow-band rugate minus filter design and fabrication approaches are discussed in detail. The experimental results, including transmittance spectrum, surface damage test and damage morphology investigated with a scanning electron microscope, demonstrate the high performance of the as-fabricated spatial filter and confirm the feasibility of the fabrication method for narrow-band rugate minus filters.展开更多
Peanut (Arachis hypogaea L.) is one of the most important oilseed crops that are cultivated worldwide. Peanut production is now greatly limited by drought stress, which is a major environmental challenge. The urgent t...Peanut (Arachis hypogaea L.) is one of the most important oilseed crops that are cultivated worldwide. Peanut production is now greatly limited by drought stress, which is a major environmental challenge. The urgent task for current peanut research is thus to study the underlying mechanisms of peanut drought tolerance, to identify genes that are closely associated with drought tolerance, and to create new germplasms/varieties with high drought tolerance. In this review, we summarize recent advances in the acclimation mechanisms to water deficiency and the genetic improvement of peanut for drought tolerance, and propose the perspectives for the future peanut research.展开更多
Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbi...Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbital angular momentum(OAM).Here we have reviewed the ways to generate THz vortex beams by two representative scenarios,i.e.,THz wavefront modulation via specific devices,and direct excitation of the helicity of THz vortex beams.The former is similar to those wavefront engineering devices in the optical and infrared(IR)domain,but just with suitable THz materials,while the latter is newly-developed in THz regime and some of the physical mechanisms still have not been explained explicitly enough though,which would provide both challenges and opportunities for THz vortex beam generation.As for their applications,thanks to the recent development of THz optics and singular optics,THz vortex beams have potentials to open doors towards a myriad of practice applications in many fields.Besides,some representative potential applications are evaluated such as THz wireless communication,THz super-resolution imaging,manipulating chiral matters,accelerating electron bunches,and detecting astrophysical sources.展开更多
A high-speed vacuum ultraviolet(VUV) imaging system has been developed on the Experimental Advanced Superconducting Tokamak(EAST), which selectively measures line emission with a central wavelength of 13.5 nm(CVI, n=4...A high-speed vacuum ultraviolet(VUV) imaging system has been developed on the Experimental Advanced Superconducting Tokamak(EAST), which selectively measures line emission with a central wavelength of 13.5 nm(CVI, n=4–2). It has been employed to study edge/pedestal plasma behavior in EAST. Edge localized mode(ELM)-induced filament structures have been captured by the VUV imaging system during the ELMy high confinement mode discharge with both high temporal and spatial resolutions. The typical features(i.e.poloidal width and pitch angle) of the observed filaments are quantitatively characterized based on the VUV imaging data, and the dependence of these features on basic plasma parameters is analyzed. It is found that the poloidal width is proportional to the heating power, and the pitch angle is inversely proportional to the edge safety factor q.95 The scatterplot shows a positive trend between the poloidal width and the ELM amplitude defined by the relative change in stored energy. These results are based on the condition that the perturbation induced by ELMs is confined to a narrow layer in the plasma.展开更多
Extreme ultraviolet(EUV) spectra emitted from low-Z impurity ions in the wavelength range of10–500Å were observed in Experimental Advanced Superconducting Tokamak(EAST)discharges. Several spectral lines from K-a...Extreme ultraviolet(EUV) spectra emitted from low-Z impurity ions in the wavelength range of10–500Å were observed in Experimental Advanced Superconducting Tokamak(EAST)discharges. Several spectral lines from K-and L-shell partially ionized ions were successfully observed with sufficient spectral intensities and resolutions for helium, lithium, boron, carbon,oxygen, neon, silicon and argon using two fast-time-response EUV spectrometers of which the spectral intensities are absolutely calibrated based on the intensity comparison method between visible and EUV bremsstrahlung continua. The wavelength is carefully calibrated using wellknown spectra. The lithium, boron and silicon are individually introduced for the wall coating of the EAST vacuum vessel to suppress mainly the hydrogen and oxygen influxes from the vacuum wall, while the carbon and oxygen intrinsically exist in the plasma. The helium is frequently used as the working gas as well as the deuterium. The neon and argon are also often used for the radiation cooling of edge plasma to reduce the heat flux onto the divertor plate. The measured spectra were analyzed mainly based on the database of National Institute of Standards and Technology. As a result, spectral lines of He Ⅱ, Li Ⅱ–Ⅲ, B Ⅳ–Ⅴ, C Ⅲ–Ⅵ, O Ⅲ–Ⅷ, Ne Ⅱ–Ⅹ,Si Ⅴ–Ⅻ, and Ar Ⅹ–XVI are identified in EAST plasmas of which the central electron temperature and chord-averaged electron density range in Te0=0.6–2.8 keV and ne=(0.5–6.0)×1019 m-3, respectively. The wavelengths and transitions of EUV lines identified here are summarized and listed in a table for each impurity species as the database for EUV spectroscopy using fusion plasmas.展开更多
Striatal neurons can be either projection neurons or interneurons, with each type exhibiting distinct susceptibility to various types of brain damage. In this study, 6-hydroxydopamine was injected into the right media...Striatal neurons can be either projection neurons or interneurons, with each type exhibiting distinct susceptibility to various types of brain damage. In this study, 6-hydroxydopamine was injected into the right medial forebrain bundle to induce dopamine depletion, and/or ibotenic acid was injected into the M1 cortex to induce motor cortex lesions. Immunohistochemistry and western blot assay showed that dopaminergic depletion results in significant loss of striatal projection neurons marked by dopamine- and cyclic adenosine monophosphate-regulated phosphoprotein, molecular weight 32 k Da, calbindin, and μ-opioid receptor, while cortical lesions reversed these pathological changes. After dopaminergic deletion, the number of neuropeptide Y-positive striatal interneurons markedly increased, which was also inhibited by cortical lesioning. No noticeable change in the number of parvalbumin-positive interneurons was found in 6-hydroxydopamine-treated rats. Striatal projection neurons and interneurons show different susceptibility to dopaminergic depletion. Further, cortical lesions inhibit striatal dysfunction and damage induced by 6-hydroxydopamine, which provides a new possibility for clinical treatment of Parkinson's disease.展开更多
Photodynamic therapy(PDT)has become an attractive tumor treatment modality because of its noninvasive feature and low side effects.However,extreme hypoxia inside solid tumors severely impedes PDT therapeutic outcome.T...Photodynamic therapy(PDT)has become an attractive tumor treatment modality because of its noninvasive feature and low side effects.However,extreme hypoxia inside solid tumors severely impedes PDT therapeutic outcome.To overcome this obstacle,various strategies have been developed recently.Among them,in situ oxygen generation,which relies on the decom-position of tumor endogenous H_(2)O_(2),and oxygen delivery tactic using high oxygen loading capacity of hemoglobin or perfluorocarbons,have been widely studied.The in situ oxygen generation strategy has high specificity to tumors,but its oxygen-generating efficiency is lim-ited by the intrinsically low tumor H_(2)O_(2)level.In contrast,the oxygen delivery approach holds advantage of high oxygen loading efficiency,nevertheless lacks tumor specificity.In this work,we prepared a nanoemulsion system containing H_(2)O_(2)-responsive catalase,highly efficient ox-ygen carrier perfiuoropolyether(PFPE),and a near-infrared(NIR)light activatable photo-sensitizer IR780,to combine the high tumor specificity of the in situ oxygen generation strategy and the high efficiency of the oxygen delivery strategy.This concisely prepared nanoplatform exhibited enhanced and H_(2)O_(2)-controllable production of singlet oxygen under light excitation,satisfactory cytocompatibility,and ability to kill cancer cells under NIR light excitation.This highlights the potential of this novel nanoplatform for highly efficient and selective NIR light mediated PDT against hypoxic tumors.This research provides new insight into the design of intelligent nanoplatform for relieving tumor hypoxia and enhancing the oxygen-dependent PDT effects in hypoxic tumors.展开更多
A new type and easy-to-fabricate metal-insulator-metal(MIM) waveguide reflector based on Sagnac loop is designed and investigated.The transfer matrix theoretical model for the transmission of electric fields in the re...A new type and easy-to-fabricate metal-insulator-metal(MIM) waveguide reflector based on Sagnac loop is designed and investigated.The transfer matrix theoretical model for the transmission of electric fields in the reflector is established,and the properties of the reflector are studied and analyzed.The simulation results indicate that the reflectivity strongly depends on the coupling splitting ratio determined by the coupling length.Accordingly, different reflectivities can be realized by varying the coupling length.For an optimum coupling length of 750 nm, the 3-dB reflection bandwidth of the MIM waveguide reflector is as wide as 1.5 μm at a wavelength of 1550 nm, and the peak reflectivity and isolation are 78%and 23 dB, respectively.展开更多
Multifocal multiphoton microscopy(MMM)has greatly improved the utilization of excitationlight and imaging speed due to parallel multiphoton excitation of the samples and simultaneousdetection of the signals,which allo...Multifocal multiphoton microscopy(MMM)has greatly improved the utilization of excitationlight and imaging speed due to parallel multiphoton excitation of the samples and simultaneousdetection of the signals,which allows it to perform three-dimensional fast fuorescence imaging.Stochastic scanming can provide continuous,uniform and high-speed excitation of the sample,which makes it a suitable scanning scheme for MMM.In this paper,the graphical programminglanguage,LabVIEW is used to achieve stochastic scanning of the two-dimensional galvo scanmers by using white noise signals to control the a and y mirrors independently.Moreover,thestochastic scanning process is simulated by using Monte Carlo method.Our results show that MMM can avoid oversampling or subsampling in the scanning area and meet the requirements of uniform sampling by stochastically scanning the individual units of the N×N foci array.Therefore,continuous and umiform scaning in the whole field of view is implemented.展开更多
基金the support from the Thousand Young Talents Program of Chinathe National Natural Science Foundation of China(Nos.51602200,61874074,21603192)+3 种基金Science and Technology Project of Shenzhen(JCYJ20170817101100705,JCYJ20170817100111548,ZDSYS201707271014468)the(Key)Project of Department of Education of Guangdong Province(No.2016KZDXM008)supported by Shenzhen Peacock Plan(No.KQTD2016053112042971)Singapore Ministry of Education Academic Research Fund Tier 2(MOE2018-T2-2-178).
文摘Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries.However,the sluggish reaction kinetics is a big obstacle for the development of high-performance sodium storage electrodes.Herein,we have rationally engineered the heterointerface by designing the Fe1?xS/MoS2 heterostructure with abundant“ion reservoir”to endow the electrode with excellent cycling stability and rate capability,which is proved by a series of in and ex situ electrochemical investigations.Density functional theory calculations further reveal that the heterointerface greatly decreases sodium ion diffusion barrier and facilitates charge-transfer kinetics.Our present findings not only provide a deep analysis on the correlation between the structure and performance,but also draw inspiration for rational heterointerface engineering toward the next-generation high-performance energy storage devices.
文摘Targeted genome engineering refers to technologies that are used for site-specific genome modifications such as knockout, knockin and transcriptional regulation of genes of interest in organisms. Site-specific recombination system, zinc finger nucleases (ZFNs), transcriptional activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9) (CRISPR/Cas9) technologies are the representatives of targeted genome engineering and have been widely used in crop basic and applied research. In this review, we introduce the basic information and action modes of these different genome engineering technologies, summarize the recent progresses of targeted genome engineering technologies and their applications in crop improvement, and propose perspectives for genome engineering-mediated modifications of crop plants in the future.
基金supported in part by the National Key R&D Program of China(Nos.2019YFE03080200,2022YFE03030001 and2022YFE03050003)National Natural Science Foundation of China(Nos.11975271,12075284,12075283 and 12175277)+1 种基金the Chinese Academy of President’s International Fellowship Initiative(No.2021VMA0022)the Post-CUP program,JSPS-CAS Bilateral Joint Research Projects,‘Control of wall recycling on metallic plasma facing materials in fusion reactor’,2019–2022,(No.GJHZ201984)。
文摘In the ELMy H-mode experiment,naturally occurring dust originating at the high-field side is clearly observed using the high-speed vacuum ultraviolet imaging system developed on the Experimental Advanced Superconducting Tokamak(EAST).The main ablation cloud shape is similar to the classical shape observed in pellet fueling experiments.However,during the dust penetration,an erupted secondary cloudlet with a bent‘cigar’shape is observed and moves upwards along the direction perpendicular to the magnetic field line,which is different to the obviation in the pellet fueling experiments.This may be due to the ion diamagnetic drift effect.The velocities of the secondary cloudlet are estimated to be 50–80 m s^(-1).In addition,a significant degradation of the plasma confinement is observed during the dust penetration.
基金the strong support from Singapore Ministry of Education via AcRF Tier 3 Programme “Geometrical Quantum Materials” (MOE2018-T3-1-002)AcRF Tier 2 grants (MOE2017-T2-1040)+7 种基金the National Natural Science Foundation of China (Grant No. 61435010)the National Natural Science Foundation of China (Grant No. 61905156)the National Natural Science Foundation of China (Grant No. 61575010)the China Postdoctoral Science Foundation (Grant No. 2017M622764)the Natural Science Foundation of Fujian Province (Grant No. 2022J01555)the Beijing Municipal Natural Science Foundation (Grant No. 4162016)the financial support of the Presidential Postdoctoral Fellowship program of the Nanyang Technological Universitysupport from the Elemental Strategy Initiative conducted by the MEXT, Japan and the CREST (JPMJCR15F3), JST
文摘Monolayer group VI transition metal dichalcogenides(TMDs)have recently emerged as promising candidates for photonic and opto-valleytronic applications.The optoelectronic properties of these atomically-thin semiconducting crystals are strongly governed by the tightly bound electron-hole pairs such as excitons and trions(charged excitons).The anomalous spin and valley configurations at the conduction band edges in monolayer WS_(2)give rise to even more fascinating valley many-body complexes.Here we find that the indirect Q valley in the first Brillouin zone of monolayer WS_(2)plays a critical role in the formation of a new excitonic state,which has not been well studied.By employing a high-quality h-BN encapsulated WS_(2)field-effect transistor,we are able to switch the electron concentration within K-Q valleys at conduction band edges.Consequently,a distinct emission feature could be excited at the high electron doping region.Such feature has a competing population with the K valley trion,and experiences nonlinear power-law response and lifetime dynamics under doping.Our findings open up a new avenue for the study of valley many-body physics and quantum optics in semiconducting 2D materials,as well as provide a promising way of valley manipulation for next-generation entangled photonic devices.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60232090 and 10774102)the Science & Technology Project from Shenzhen Government of China (Grant Nos. 2008340 and 200717)
文摘An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented.
基金support from the National Basic Research Program of China (2014CB239702)National Natural Science Foundation of China (Grant Nos. 21371121, 21506126 and 51502174)+1 种基金Shenzhen Science and Technology Research Foundation (Grant Nos. JCYJ20150324141711645,JCYJ20150324141711616 and JCYJ20150626090504916)China Postdoctoral Science Foundation (2015 M582401 and 2015 M572349)
文摘A Ni Fe_2O_4/expanded graphite(Ni Fe_2O_4/EG)nanocomposite was prepared via a simple and inexpensive synthesis method. Its lithium storage properties were studied with the goal of applying it as an anode in a lithium-ion battery. The obtained nanocomposite exhibited a good cycle performance, with a capacity of 601 m Ah g^(-1)at a current of 1 A g^(-1)after 800 cycles. This good performance may beattributed to the enhanced electrical conductivity and layered structure of the EG. Its high mechanical strength could postpone the disintegration of the nanocomposite structure,efficiently accommodate volume changes in the Ni Fe_2O_4-based anodes, and alleviate aggregation of Ni Fe_2O_4 nanoparticles.
基金the National Natural Science Foundation of China(61435010 and 61575089,H.Z.)the Science and Technology Innovation Commission of Shenzhen(KQTD-2015032416270385 and JCYJ20150625103619275,H.Z.)+2 种基金the China Postdoctoral Science Foundation(2017M610540,2018T110892,M.Q.)the Natural Science Foundation of Shandong Province,China(ZR2016BB33,M.Q.)the Natural Science Foundation of Guangdong Province,China(2018A030310500,M.Q.).
文摘Single-or few-layer black phosphorus(FLBP)has attracted great attentions in scientic community with its excellent properties,including biodegradability,unique puckered lattice conguration,attractive electrical properties and direct and tunable band gap.In recent years,FLBP has been widely studied in bio-photonicelds such as photothermal and photodynamic therapy,drug delivery,bioimaging and biosensor,showing attractive clinical potential.Because of the marked advantages of FLBP nanomaterials in bio-photonicelds,this review article reviews the latest advances of biomaterials based on FLBP in biomedical applications,ranging from biocompatibility,medical diagnosis to treatment.
基金Supported by National Natural Science Foundation of China,No.81202396 and No.81273374grants from the Science Foundation of Shenzhen,No.JCYJ20130326112757843
文摘AIM: To investigate the effects of our tumor vaccines on reversing immune tolerance and generating therapeutic response.METHODS: Vaccines were synthesized by solid phase using an Fmoc strategy,where a small molecule toll-like receptor-7 agonist(T7) was conjugated to a monoclonal gastric cancer 7 antigen mono-epitope(T7-MG1) or tri-epitope(T7-MG3).Cytokines were measured in both mouse bone marrow dendritic cells and mouse spleen lymphocytes after exposed to the vaccines.BALB/c mice were intraperitoneally immunized with the vaccines every 2 wk for a total of three times,andthen subcutaneously challenged with Ehrlich ascites carcinoma(EAC) cells.Three weeks later,the mice were killed,and the tumors were surgically removed and weighed.Serum samples were collected from the mice,and antibody titers were determined by ELISA using an alkaline phosphate-conjugated detection antibody for total Ig G.Antibody-dependent cell-mediated cytotoxicity was detected by the lactate dehydrogenase method using natural killer cells as effectors and antibody-labeled EAC cells as targets.Cytotoxic T lymphocyte activities were also detected by the lactate dehydrogenase method using lymphocytes as effectors and EAC cells as targets.RESULTS: Vaccines were successfully synthesized and validated by analytical high performance liquid chromatography and electrospray mass spectrometry,including T7,T7-MG1,and T7-MG3.Rapid inductions of tumor necrosis factor-α and interleukin-12 in bone marrow dendritic cells and interferon γ and interleukin-12 in lymphocytes occurred in vitro after T7,T7-MG1,and T7-MG3 treatment.Immunization with T7-MG3 reduced the EAC tumor burden in BALB/c mice to 62.64% ± 5.55% compared with PBS control(P < 0.01).Six or nine weeks after the first immunization,the monoclonal gastric cancer 7 antigen antibody increased significantly in the T7-MG3 group compared with the PBS control(P < 0.01).As for antibody-dependent cell-mediated cytotoxicity,antisera obtained by immunization with T7-MG3 were able to markedly enhance cell lysis compared to PBS control(31.58% ± 2.94% vs 18.02% ± 2.26%; P < 0.01).As for cytotoxic T lymphocytes,T7-MG3 exhibited obviously greater cytotoxicity compared with PBS control(40.92% ± 4.38% vs 16.29% ± 1.90%; P < 0.01).CONCLUSION: A successful method is confirmed for the design of gastric cancer vaccines by chemical conjugation of T7 and multi-repeat-epitope of monoclonal gastric cancer 7 antigen.
基金supported by the National Natural Science Foundation of China,No.81372041(to DW),and No.81801220(to MGZ)
文摘We previously demonstrated that overexpression of tropomyosin receptor kinase A(TrkA)promotes the survival and Schwann celllike differentiation of bone marrow stromal stem cells in nerve grafts,thereby enhancing the regeneration and functional recovery of the peripheral nerve.In the present study,we investigated the molecular mechanisms underlying the neuroprotective effects of TrkA in bone marrow stromal stem cells seeded into nerve grafts.Bone marrow stromal stem cells from Sprague-Dawley rats were infected with recombinant lentivirus vector expressing rat TrkA,TrkA-shRNA or the respective control.The cells were then seeded into allogeneic rat acellular nerve allografts for bridging a 1-cm right sciatic nerve defect.Then,8 weeks after surgery,hematoxylin and eosin staining showed that compared with the control groups,the cells and fibers in the TrkA overexpressing group were more densely and uniformly arranged,whereas they were relatively sparse and arranged in a disordered manner in the TrkA-shRNA group.Western blot assay showed that compared with the control groups,the TrkA overexpressing group had higher expression of the myelin marker,myelin basic protein and the axonal marker neurofilament 200.The TrkA overexpressing group also had higher levels of various signaling molecules,including TrkA,pTrkA(Tyr490),extracellular signal-regulated kinases 1/2(Erkl/2),pErk1/2(Thr202/Tyr204),and the anti-apoptotic proteins Bcl-2 and Bcl-xL.In contrast,these proteins were downregulated,while the pro-apoptotic factors Bax and Bad were upregulated,in the TrkA-shRNA group.The levels of the TrkA effectors Akt and pAkt(Ser473)were not different among the groups.These results suggest that TrkA enhances the survival and regenerative capacity of bone marrow stromal stem cells through upregulation of the Erk/Bcl-2 pathway.All procedures were approved by the Animal Ethical and Welfare Committee of Shenzhen University,China in December 2014(approval No.AEWC-2014-001219).
基金Supported by the National Key R&D Program of China under Grant No 2016YFA0401100the National Natural Science Foundation of China under Grant No 61575129the National High-Technology Research and Development Program of China under Grant No 2015AA021102
文摘In our previous study, metals have been used as absorbers in the clear plastic laser transmission welding. The effects of metal thermal conductivity on the welding quality are investigated in the present work. Four metals with distinctly different thermal conductivities, i.e., titanium, nickel, molybdenum, and copper, are selected as light absorbers. The lap welding is conducted with an 808 nm diode laser and simulation experiments are also conducted. Nickel electroplating test is carried out to minimize the side-effects from different light absorptivities of different metals. The results show that the welding with an absorber of higher thermal conductivity can accommodate higher laser input power before smoking, which produces a wider and stronger welding seam.The positive role of the higher thermal conductivity can be attributed to the fact that a desirable thermal field distribution for the molecular diffusion and entanglement is produced from the case with a high thermal conductivity.
基金supported by the National Natural Science Foundation of China in 2012(31201609).
文摘WRKY transcription factors are involved in defense responses caused by biotic stresses.Phylloxera(Daktulosphaira vitifoliae Fitch),a pest widespread in viticulture,elicits transcriptional reprogramming of plant defense-associated components,such as regulons related to WRKYs and salicylic acid(SA)signaling.In this study,we characterized WRKY46,a WRKY transcription factor responsible for phylloxera attack,and revealed the molecular mechanism for WRKY-mediated defense responses to phylloxera.qRT-PCR and GUS staining analyses revealed that WRKY46 is induced in response to phylloxera damage and mechanical wounding.VvWRKY46 is a nuclear-localized transcription factor that activates its downstream target VvCHIB by direct protein–DNA interaction.Regulons involved in the SA-mediated defense response were regulated during incompatible interactions between“1103 Paulsen”rootstock and phylloxera.In addition,WRKY46 exhibited a higher transcript abundance in“1103 Paulsen”than in“Crimson Seedless”,regardless of whether the plants were infected with phylloxera.Furthermore,the enhanced expression of VvWRKY46 significantly attenuated phylloxera attack and delayed nymph development of composite grape plants.In summary,we demonstrated that WRKY46 plays a role in the SA-mediated defense-regulatory network by directly binding to the downstream structural gene VvCHIB.The phylloxera-responsive gene WRKY46 was identified,which could improve the understanding of the basic mechanism of grapevine in response to phylloxera.
基金Project supported by the Postdoctoral Science Foundation of China(Grant Nos.2016M592528 and 2016M602517)the Natural Science Foundation of Guangdong Province,China(Grant No.2017A030310130)the National Natural Science Foundation of China(Grant No.11705259)
文摘The design, fabrication and performance of narrow-band rugate minus filters are investigated in this paper. A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O2) and high(Al2 O3) refractive index materials is presented to fabricate a rugate structure. The narrow-band rugate minus filter design and fabrication approaches are discussed in detail. The experimental results, including transmittance spectrum, surface damage test and damage morphology investigated with a scanning electron microscope, demonstrate the high performance of the as-fabricated spatial filter and confirm the feasibility of the fabrication method for narrow-band rugate minus filters.
文摘Peanut (Arachis hypogaea L.) is one of the most important oilseed crops that are cultivated worldwide. Peanut production is now greatly limited by drought stress, which is a major environmental challenge. The urgent task for current peanut research is thus to study the underlying mechanisms of peanut drought tolerance, to identify genes that are closely associated with drought tolerance, and to create new germplasms/varieties with high drought tolerance. In this review, we summarize recent advances in the acclimation mechanisms to water deficiency and the genetic improvement of peanut for drought tolerance, and propose the perspectives for the future peanut research.
基金Project supported partly by the National Natural Science Foundation of China(Grant Nos.61775142 and 61705132)Shenzhen Fundamental Research and Discipline Layout Project,China(Grant Nos.JCYJ20170412105812811,JCYJ20190808164007485,JCYJ20190808121817100,and JCYJ20190808115601653).
文摘Last decade has witnessed a rapid development of the generation of terahertz(THz)vortex beams as well as their wide applications,mainly due to their unique combination characteristics of regular THz radiation and orbital angular momentum(OAM).Here we have reviewed the ways to generate THz vortex beams by two representative scenarios,i.e.,THz wavefront modulation via specific devices,and direct excitation of the helicity of THz vortex beams.The former is similar to those wavefront engineering devices in the optical and infrared(IR)domain,but just with suitable THz materials,while the latter is newly-developed in THz regime and some of the physical mechanisms still have not been explained explicitly enough though,which would provide both challenges and opportunities for THz vortex beam generation.As for their applications,thanks to the recent development of THz optics and singular optics,THz vortex beams have potentials to open doors towards a myriad of practice applications in many fields.Besides,some representative potential applications are evaluated such as THz wireless communication,THz super-resolution imaging,manipulating chiral matters,accelerating electron bunches,and detecting astrophysical sources.
基金supported in part by the National Key R&D Program of China (No. 2017YFE0301205)National Natural Science Foundation of China (Nos. 11975271, 12075284 and 12075283)partly supported by Chinese Academy of President’s International Fellowship Initiative (Grant No. 2021 VMA0022)。
文摘A high-speed vacuum ultraviolet(VUV) imaging system has been developed on the Experimental Advanced Superconducting Tokamak(EAST), which selectively measures line emission with a central wavelength of 13.5 nm(CVI, n=4–2). It has been employed to study edge/pedestal plasma behavior in EAST. Edge localized mode(ELM)-induced filament structures have been captured by the VUV imaging system during the ELMy high confinement mode discharge with both high temporal and spatial resolutions. The typical features(i.e.poloidal width and pitch angle) of the observed filaments are quantitatively characterized based on the VUV imaging data, and the dependence of these features on basic plasma parameters is analyzed. It is found that the poloidal width is proportional to the heating power, and the pitch angle is inversely proportional to the edge safety factor q.95 The scatterplot shows a positive trend between the poloidal width and the ELM amplitude defined by the relative change in stored energy. These results are based on the condition that the perturbation induced by ELMs is confined to a narrow layer in the plasma.
基金supported by National Key Research and Development Program of China(Nos.2018YFE0311100,2017YFE0300402,2017YFE0301300)National Natural Science Foundation of China(Nos.Nos.11905146,11775269,U1832126,11805133)+1 种基金Hefei Science Center High-end User Development Fund Project(2019HSCUE014)Chinese Academy of Sciences President’s International Fellowship Initiative(PIFI)(2020VMA0001)。
文摘Extreme ultraviolet(EUV) spectra emitted from low-Z impurity ions in the wavelength range of10–500Å were observed in Experimental Advanced Superconducting Tokamak(EAST)discharges. Several spectral lines from K-and L-shell partially ionized ions were successfully observed with sufficient spectral intensities and resolutions for helium, lithium, boron, carbon,oxygen, neon, silicon and argon using two fast-time-response EUV spectrometers of which the spectral intensities are absolutely calibrated based on the intensity comparison method between visible and EUV bremsstrahlung continua. The wavelength is carefully calibrated using wellknown spectra. The lithium, boron and silicon are individually introduced for the wall coating of the EAST vacuum vessel to suppress mainly the hydrogen and oxygen influxes from the vacuum wall, while the carbon and oxygen intrinsically exist in the plasma. The helium is frequently used as the working gas as well as the deuterium. The neon and argon are also often used for the radiation cooling of edge plasma to reduce the heat flux onto the divertor plate. The measured spectra were analyzed mainly based on the database of National Institute of Standards and Technology. As a result, spectral lines of He Ⅱ, Li Ⅱ–Ⅲ, B Ⅳ–Ⅴ, C Ⅲ–Ⅵ, O Ⅲ–Ⅷ, Ne Ⅱ–Ⅹ,Si Ⅴ–Ⅻ, and Ar Ⅹ–XVI are identified in EAST plasmas of which the central electron temperature and chord-averaged electron density range in Te0=0.6–2.8 keV and ne=(0.5–6.0)×1019 m-3, respectively. The wavelengths and transitions of EUV lines identified here are summarized and listed in a table for each impurity species as the database for EUV spectroscopy using fusion plasmas.
基金supported by the National Natural Science Foundation of China,No.81471288
文摘Striatal neurons can be either projection neurons or interneurons, with each type exhibiting distinct susceptibility to various types of brain damage. In this study, 6-hydroxydopamine was injected into the right medial forebrain bundle to induce dopamine depletion, and/or ibotenic acid was injected into the M1 cortex to induce motor cortex lesions. Immunohistochemistry and western blot assay showed that dopaminergic depletion results in significant loss of striatal projection neurons marked by dopamine- and cyclic adenosine monophosphate-regulated phosphoprotein, molecular weight 32 k Da, calbindin, and μ-opioid receptor, while cortical lesions reversed these pathological changes. After dopaminergic deletion, the number of neuropeptide Y-positive striatal interneurons markedly increased, which was also inhibited by cortical lesioning. No noticeable change in the number of parvalbumin-positive interneurons was found in 6-hydroxydopamine-treated rats. Striatal projection neurons and interneurons show different susceptibility to dopaminergic depletion. Further, cortical lesions inhibit striatal dysfunction and damage induced by 6-hydroxydopamine, which provides a new possibility for clinical treatment of Parkinson's disease.
基金This work was supported by the National Natural Science Foundation of China(61525503/61835009/61722508/61935012/61620106016)(Key)Project of Department of Education of Guangdong Province(2016KCXTD007),Shenzhen Science and Technology Funding(JCYJ20180305124902165/JCYJ20170412105003520).TEM analysis was supported by the Instrumental Analysis Center of Shenzhen University.
文摘Photodynamic therapy(PDT)has become an attractive tumor treatment modality because of its noninvasive feature and low side effects.However,extreme hypoxia inside solid tumors severely impedes PDT therapeutic outcome.To overcome this obstacle,various strategies have been developed recently.Among them,in situ oxygen generation,which relies on the decom-position of tumor endogenous H_(2)O_(2),and oxygen delivery tactic using high oxygen loading capacity of hemoglobin or perfluorocarbons,have been widely studied.The in situ oxygen generation strategy has high specificity to tumors,but its oxygen-generating efficiency is lim-ited by the intrinsically low tumor H_(2)O_(2)level.In contrast,the oxygen delivery approach holds advantage of high oxygen loading efficiency,nevertheless lacks tumor specificity.In this work,we prepared a nanoemulsion system containing H_(2)O_(2)-responsive catalase,highly efficient ox-ygen carrier perfiuoropolyether(PFPE),and a near-infrared(NIR)light activatable photo-sensitizer IR780,to combine the high tumor specificity of the in situ oxygen generation strategy and the high efficiency of the oxygen delivery strategy.This concisely prepared nanoplatform exhibited enhanced and H_(2)O_(2)-controllable production of singlet oxygen under light excitation,satisfactory cytocompatibility,and ability to kill cancer cells under NIR light excitation.This highlights the potential of this novel nanoplatform for highly efficient and selective NIR light mediated PDT against hypoxic tumors.This research provides new insight into the design of intelligent nanoplatform for relieving tumor hypoxia and enhancing the oxygen-dependent PDT effects in hypoxic tumors.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61827815 and 61775142)
文摘A new type and easy-to-fabricate metal-insulator-metal(MIM) waveguide reflector based on Sagnac loop is designed and investigated.The transfer matrix theoretical model for the transmission of electric fields in the reflector is established,and the properties of the reflector are studied and analyzed.The simulation results indicate that the reflectivity strongly depends on the coupling splitting ratio determined by the coupling length.Accordingly, different reflectivities can be realized by varying the coupling length.For an optimum coupling length of 750 nm, the 3-dB reflection bandwidth of the MIM waveguide reflector is as wide as 1.5 μm at a wavelength of 1550 nm, and the peak reflectivity and isolation are 78%and 23 dB, respectively.
基金partially supported,by,the National Natural Science Foundation of China(11204226)the Fundamental Research Fundsfor,the Central Universities(K5051005006,K5051305002).
文摘Multifocal multiphoton microscopy(MMM)has greatly improved the utilization of excitationlight and imaging speed due to parallel multiphoton excitation of the samples and simultaneousdetection of the signals,which allows it to perform three-dimensional fast fuorescence imaging.Stochastic scanming can provide continuous,uniform and high-speed excitation of the sample,which makes it a suitable scanning scheme for MMM.In this paper,the graphical programminglanguage,LabVIEW is used to achieve stochastic scanning of the two-dimensional galvo scanmers by using white noise signals to control the a and y mirrors independently.Moreover,thestochastic scanning process is simulated by using Monte Carlo method.Our results show that MMM can avoid oversampling or subsampling in the scanning area and meet the requirements of uniform sampling by stochastically scanning the individual units of the N×N foci array.Therefore,continuous and umiform scaning in the whole field of view is implemented.