Effect of hydrogen （142） treatment during the GaN barrier growth on the electroluminescence performance of green InGaN/GaN single-quantum-well light-emitting diodes （LEDs） grown on Si substrates is experimentally ...Effect of hydrogen （142） treatment during the GaN barrier growth on the electroluminescence performance of green InGaN/GaN single-quantum-well light-emitting diodes （LEDs） grown on Si substrates is experimentally investigated. We prepare two LED samples with different carrier gas compositions during the growth of GaN barrier. In the H2 free LED, the GaN barrier is grown in full nitrogen （N2） atmosphere. For the other H2 treated LED, a mixture of N2 and H2 was used as the carrier gas. It is observed that V-shaped pits decrease in size after H2 treatment by means of the scanning electron microscope. Due to the fact that the p n junction interface would be closer to the p-GaN as a result of smaller V-shaped pits, the tunneling barrier for holes to inject into the InGaN quantum well would become thicker after tt2 treatment. Hence, the external quantum efficiency of the H2 treated LED is lower compared to the H2 free LED. However, LEDs would exhibit a better leakage behavior after H2 treatment during the GaN barrier growth because of more effective blocking of the threading dislocations as a result of the H2 etching at V-shaped pits.展开更多
To understand how the nervous system develops from a small pool of progenitors during early embryonic development,it is fundamentally important to identify the diversity of neuronal subtypes,decode the origin of neuro...To understand how the nervous system develops from a small pool of progenitors during early embryonic development,it is fundamentally important to identify the diversity of neuronal subtypes,decode the origin of neuronal diversity,and uncover the principles governing neuronal specification across different regions.Recent single-cell analyses have systematically identified neuronal diversity at unprecedented scale and speed,leaving the deconstruction of spatiotemporal mechanisms for generating neuronal diversity an imperative and paramount challenge.In this review,we highlight three distinct strategies deployed by neural progenitors to produce diverse neuronal subtypes,including predetermined,stochastic,and cascade diversifying models,and elaborate how these strategies are implemented in distinct regions such as the neocortex,spinal cord,retina,and hypothalamus.Importantly,the identity of neural progenitors is defined by their spatial position and temporal patterning factors,and each type of progenitor cell gives rise to distinguishable cohorts of neuronal subtypes.Microenvironmental cues,spontaneous activity,and connectional pattern further reshape and diversify the fate of unspecialized neurons in particular regions.The illumination of how neuronal diversity is generated will pave the way for producing specific brain organoids to model human disease and desired neuronal subtypes for cell therapy,as well as understanding the organization of functional neural circuits and the evolution of the nervous system.展开更多
A novel knottedl-like homeobox （knox） gene, Pttknl （Populus tremulaxtremuloides knottedl）, isolated from the cambial region of hybrid aspen, was introduced into Petunia hybrida Vilm. using the leafdisc method medi...A novel knottedl-like homeobox （knox） gene, Pttknl （Populus tremulaxtremuloides knottedl）, isolated from the cambial region of hybrid aspen, was introduced into Petunia hybrida Vilm. using the leafdisc method mediated by Agrobacterium. A series of novel phenotypes was observed in transgenic petunia plants, including the formation of ectopic spikes on the adaxial surface of corollas and small petals on the abaxial surface of corollas, fusion of floral organs, shortening of corolla midribs, the formation of tumor-like knots along the midrib on the abaxial surface and serrated lobs of corolla margins, and alterations in petal color; except for changes in the leaves and plant architecture, RT-PCR showed that the Pttknl gene was expressed in the leaves of different petunia transgenic plants, whereas no signal was detected in wild-type plants. The possible function of Pttknl in leaf and flower development is discussed.展开更多
The corrosion behavior of CoCrFeNiMo_x alloys was investigated in aqueous environments, NaCl and H_2SO_4 solutions,respectively, to simulate typical neutral and acidic conditions. The cyclic polarization curves in NaC...The corrosion behavior of CoCrFeNiMo_x alloys was investigated in aqueous environments, NaCl and H_2SO_4 solutions,respectively, to simulate typical neutral and acidic conditions. The cyclic polarization curves in NaCl and the potentiodynamic curves in H_2SO_4 clearly reveal the beneficial effects of Mo and the detrimental effect of σ-phase on the corrosion resistance. The X-ray photoelectron spectroscopy results of CoCrFeNiMo_x alloys in H_2SO_4 solution indicate that Cr and Mo predominate the corroded surface of the alloys, where Mo primarily exists in the form of MoO_3.展开更多
The association of Zika virus(ZIKV)infection with microcephaly has raised alarm worldwide.Their causal link has been confirmed in different animal models infected by ZIKV.However,the molecular mechanisms underlying ZI...The association of Zika virus(ZIKV)infection with microcephaly has raised alarm worldwide.Their causal link has been confirmed in different animal models infected by ZIKV.However,the molecular mechanisms underlying ZIKV pathogenesis are far from clear.Hence,we performed global gene expression analysis of ZIKV-infected mouse brains to unveil the biological and molecular networks underpinning microcephaly.We found significant dysregulation of the sub-networks associated with brain development,immune response,cell death,microglial cell activation,and autophagy amongst others.We provided detailed analysis of the related complicated gene networks and the links between them.Additionally,we analyzed the signaling pathways that were likely to be involved.This report provides systemic insights into not only the pathogenesis,but also a path to the development of prophylactic and therapeutic strategies against ZIKV infection.展开更多
Fibroblast growth factor(FGF)7,a member of FGF family,is initially found to be secreted from mesenchymal cells to repair epithelial tissues.However,its functions in the nervous system are largely unknown.The present s...Fibroblast growth factor(FGF)7,a member of FGF family,is initially found to be secreted from mesenchymal cells to repair epithelial tissues.However,its functions in the nervous system are largely unknown.The present study showed that FGF7 was a neuromodulator localized in the large dense-core vesicles(LDCVs)in nociceptive neurons.FGF7 was mainly expressed in small-diameter neurons of the dorsal root ganglion and could be transported to the dorsal spinal cord.Interestingly,FGF7 was mostly stored in LDCVs that did not contain neuropeptide substance P.Electrophysiological recordings in the spinal cord slice showed that buffer-applied FGF7 increased the amplitude of excitatory post-synaptic current evoked by stimulating the sensory afferent fibers.Behavior tests showed that intrathecally applied FGF7 potentiated the formalin-induced acute nociceptive response.Moreover,both acute and inflammatory nociceptive responses were significantly reduced in Fgf7-deficient mice.These results suggest that FGF7 exerts an excitatory modulation of nociceptive afferent transmission.展开更多
The objective of this work was to produce citric acid from corn starch using a newly isolated mutant of Aspergillus niger, and to analyze the relationship between changes in the physiological properties of A. niger in...The objective of this work was to produce citric acid from corn starch using a newly isolated mutant of Aspergillus niger, and to analyze the relationship between changes in the physiological properties of A. niger induced by carbon ion irradiation and citric acid accumulation. Our results showed that the physiological characteristics of conidia in A. niger were closely related to citric acid accumulation and that lower growth rate and viability of conidia may be beneficial to citric acid accumulation. Using corn starch as a raw material, a high-yielding citric acid mutant, named HW2, was obtained. In a 10-L bioreactor, HW2 can accumulate 118.9 g/L citdc acid with a residual total sugar concentration of only 14.4 g/L. This represented an 18% increase in citric acid accumulation and a 12.5% decrease in sugar utilization compared with the original strain.展开更多
Aging is a slow and progressive natural process that compromises the normal functions of cells,tissues,organs,and systems.The aging of the hypothalamic median eminence(ME),a structural gate linking neural and endocrin...Aging is a slow and progressive natural process that compromises the normal functions of cells,tissues,organs,and systems.The aging of the hypothalamic median eminence(ME),a structural gate linking neural and endocrine systems,may impair hormone release,energy homeostasis,and central sensing of circulating molecules,leading to systemic and reproductive aging.However,the molecular and cellular features of ME aging remain largely unknown.Here,we describe the transcriptional landscape of young and middleaged mouse ME at single-cell resolution,revealing the common and cell type-specific transcriptional changes with age.The transcriptional changes in cell-intrinsic programs,cell-cell crosstalk,and cellextrinsic factors highlight five molecular features of ME aging and also implicate several potentially druggable targets at cellular,signaling,and molecular levels.Importantly,our results suggest that vascular and leptomeningeal cells may lead the asynchronized aging process among diverse cell types and drive local inflammation and cellular senescence via a unique secretome.Together,our study uncovers how intrinsic and extrinsic features of each cell type in the hypothalamic ME are changed by the aging process,which will facilitate our understanding of brain aging and provide clues for efficient anti-aging intervention at the middle-aged stage.展开更多
基金Supported by the National Key R&D Program of China under Grant Nos 2016YFB0400600 and 2016YFB0400601the State Key Program of the National Natural Science Foundation of China under Grant No 61334001+2 种基金the National Natural Science Foundation of China under Grant Nos 21405076,11674147,61604066,51602141 and 11604137the Key Technology Research and Development Program of Jiangxi Province under Grant Nos 20165ABC28007 and 20171BBE50052Jiangxi Province Postdoctoral Science Foundation Funded Project under Grant No 2015KY32
文摘Effect of hydrogen （142） treatment during the GaN barrier growth on the electroluminescence performance of green InGaN/GaN single-quantum-well light-emitting diodes （LEDs） grown on Si substrates is experimentally investigated. We prepare two LED samples with different carrier gas compositions during the growth of GaN barrier. In the H2 free LED, the GaN barrier is grown in full nitrogen （N2） atmosphere. For the other H2 treated LED, a mixture of N2 and H2 was used as the carrier gas. It is observed that V-shaped pits decrease in size after H2 treatment by means of the scanning electron microscope. Due to the fact that the p n junction interface would be closer to the p-GaN as a result of smaller V-shaped pits, the tunneling barrier for holes to inject into the InGaN quantum well would become thicker after tt2 treatment. Hence, the external quantum efficiency of the H2 treated LED is lower compared to the H2 free LED. However, LEDs would exhibit a better leakage behavior after H2 treatment during the GaN barrier growth because of more effective blocking of the threading dislocations as a result of the H2 etching at V-shaped pits.
基金supported by the National Key R&D Program of China(2019YFA0801900 and 2018YFA0801104)the National Natural Science Foundation of China(81891002,32070972,31921002,and 31771131)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB32020000)the Hundred-Talent Program(Chinese Academy of Sciences)the Beijing Municipal Science&Technology Commission(Z210010 and Z181100001518001).
文摘To understand how the nervous system develops from a small pool of progenitors during early embryonic development,it is fundamentally important to identify the diversity of neuronal subtypes,decode the origin of neuronal diversity,and uncover the principles governing neuronal specification across different regions.Recent single-cell analyses have systematically identified neuronal diversity at unprecedented scale and speed,leaving the deconstruction of spatiotemporal mechanisms for generating neuronal diversity an imperative and paramount challenge.In this review,we highlight three distinct strategies deployed by neural progenitors to produce diverse neuronal subtypes,including predetermined,stochastic,and cascade diversifying models,and elaborate how these strategies are implemented in distinct regions such as the neocortex,spinal cord,retina,and hypothalamus.Importantly,the identity of neural progenitors is defined by their spatial position and temporal patterning factors,and each type of progenitor cell gives rise to distinguishable cohorts of neuronal subtypes.Microenvironmental cues,spontaneous activity,and connectional pattern further reshape and diversify the fate of unspecialized neurons in particular regions.The illumination of how neuronal diversity is generated will pave the way for producing specific brain organoids to model human disease and desired neuronal subtypes for cell therapy,as well as understanding the organization of functional neural circuits and the evolution of the nervous system.
基金Supported by the Gansu Provincial Natural Science Foundation of China （ZS021-A25-047-N） and Xi＇an Urban Rural Construction Committee.Acknowledgements The authors thank Dr. 0lof 0lsson （Goeteberg University, Goeteberg, Sweden） for providing the plasmid containing 35S：：Pttkn1.
文摘A novel knottedl-like homeobox （knox） gene, Pttknl （Populus tremulaxtremuloides knottedl）, isolated from the cambial region of hybrid aspen, was introduced into Petunia hybrida Vilm. using the leafdisc method mediated by Agrobacterium. A series of novel phenotypes was observed in transgenic petunia plants, including the formation of ectopic spikes on the adaxial surface of corollas and small petals on the abaxial surface of corollas, fusion of floral organs, shortening of corolla midribs, the formation of tumor-like knots along the midrib on the abaxial surface and serrated lobs of corolla margins, and alterations in petal color; except for changes in the leaves and plant architecture, RT-PCR showed that the Pttknl gene was expressed in the leaves of different petunia transgenic plants, whereas no signal was detected in wild-type plants. The possible function of Pttknl in leaf and flower development is discussed.
基金supported financially by the National Natural Science Foundation of China (Nos. 51471133 and 51771149)
文摘The corrosion behavior of CoCrFeNiMo_x alloys was investigated in aqueous environments, NaCl and H_2SO_4 solutions,respectively, to simulate typical neutral and acidic conditions. The cyclic polarization curves in NaCl and the potentiodynamic curves in H_2SO_4 clearly reveal the beneficial effects of Mo and the detrimental effect of σ-phase on the corrosion resistance. The X-ray photoelectron spectroscopy results of CoCrFeNiMo_x alloys in H_2SO_4 solution indicate that Cr and Mo predominate the corroded surface of the alloys, where Mo primarily exists in the form of MoO_3.
基金This work was supported by the Strategic Priority Research Program and Innovation Program of the Chinese Academy of Sciences,China(Grant Nos.XDB32020100,XDA16010306,QYZDJ-SSW-SMC007,and GJHZ1827)the National Natural Science Foundation of China(Grant Nos.31730108,31430037,31571038,and 31871329)the Natural Science Foundation of Shanghai,China(Grant No.17ZR1413900).
文摘The association of Zika virus(ZIKV)infection with microcephaly has raised alarm worldwide.Their causal link has been confirmed in different animal models infected by ZIKV.However,the molecular mechanisms underlying ZIKV pathogenesis are far from clear.Hence,we performed global gene expression analysis of ZIKV-infected mouse brains to unveil the biological and molecular networks underpinning microcephaly.We found significant dysregulation of the sub-networks associated with brain development,immune response,cell death,microglial cell activation,and autophagy amongst others.We provided detailed analysis of the related complicated gene networks and the links between them.Additionally,we analyzed the signaling pathways that were likely to be involved.This report provides systemic insights into not only the pathogenesis,but also a path to the development of prophylactic and therapeutic strategies against ZIKV infection.
基金This work was supported by the National Natural Science Foundation of China(31130066)the Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDB01020300).
文摘Fibroblast growth factor(FGF)7,a member of FGF family,is initially found to be secreted from mesenchymal cells to repair epithelial tissues.However,its functions in the nervous system are largely unknown.The present study showed that FGF7 was a neuromodulator localized in the large dense-core vesicles(LDCVs)in nociceptive neurons.FGF7 was mainly expressed in small-diameter neurons of the dorsal root ganglion and could be transported to the dorsal spinal cord.Interestingly,FGF7 was mostly stored in LDCVs that did not contain neuropeptide substance P.Electrophysiological recordings in the spinal cord slice showed that buffer-applied FGF7 increased the amplitude of excitatory post-synaptic current evoked by stimulating the sensory afferent fibers.Behavior tests showed that intrathecally applied FGF7 potentiated the formalin-induced acute nociceptive response.Moreover,both acute and inflammatory nociceptive responses were significantly reduced in Fgf7-deficient mice.These results suggest that FGF7 exerts an excitatory modulation of nociceptive afferent transmission.
基金supported by the Agriculture Science Technology Achievement Transformation Fund(No.2013GB24910680),China
文摘The objective of this work was to produce citric acid from corn starch using a newly isolated mutant of Aspergillus niger, and to analyze the relationship between changes in the physiological properties of A. niger induced by carbon ion irradiation and citric acid accumulation. Our results showed that the physiological characteristics of conidia in A. niger were closely related to citric acid accumulation and that lower growth rate and viability of conidia may be beneficial to citric acid accumulation. Using corn starch as a raw material, a high-yielding citric acid mutant, named HW2, was obtained. In a 10-L bioreactor, HW2 can accumulate 118.9 g/L citdc acid with a residual total sugar concentration of only 14.4 g/L. This represented an 18% increase in citric acid accumulation and a 12.5% decrease in sugar utilization compared with the original strain.
基金supported by the National Key R&D Program of China(2019YFA0801900 and 2018YFA0801104)the National Natural Science Foundation of China(31771131,81891002,31921002,and 32070972)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB32020000)the Hundred-Talent Program(Chinese Academy of Sciences)the Beijing Municipal Science&Technology Commission(Z210010 and Z181100001518001)the Baoding Technical Program(2141ZF027)。
文摘Aging is a slow and progressive natural process that compromises the normal functions of cells,tissues,organs,and systems.The aging of the hypothalamic median eminence(ME),a structural gate linking neural and endocrine systems,may impair hormone release,energy homeostasis,and central sensing of circulating molecules,leading to systemic and reproductive aging.However,the molecular and cellular features of ME aging remain largely unknown.Here,we describe the transcriptional landscape of young and middleaged mouse ME at single-cell resolution,revealing the common and cell type-specific transcriptional changes with age.The transcriptional changes in cell-intrinsic programs,cell-cell crosstalk,and cellextrinsic factors highlight five molecular features of ME aging and also implicate several potentially druggable targets at cellular,signaling,and molecular levels.Importantly,our results suggest that vascular and leptomeningeal cells may lead the asynchronized aging process among diverse cell types and drive local inflammation and cellular senescence via a unique secretome.Together,our study uncovers how intrinsic and extrinsic features of each cell type in the hypothalamic ME are changed by the aging process,which will facilitate our understanding of brain aging and provide clues for efficient anti-aging intervention at the middle-aged stage.
