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cLE peptide-mediated signaling in shoot and vascular meristem development

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Frontiers in Biology 2017年第6期12卷 406-420页

作者： Thai q. Dao Jennifer c. Fletcher Plant Gene Expression center United States Department of Agriculture-Agricultural Research Service Albany CA 9471 O USA Department of Plant and Microbial Biology University of California Berkeley Berkeley CA 94720 USA

Multicellular organisms rely on the transmission of information between cells to coordinate various biological processes during growth and development. Plants, like animals, utilize small peptide ligands as signaling molecules to transmit information between cells. These polypeptides typically act as extracellular messengers that are perceived by membrane-bound receptors, which then transduce the signal into the recipient cell to modify downstream gene transcription. The cLAVATA3/EMBRYO SURROUNDING REGION-RELATED (cLE) proteins represent one of the largest and best understood families of small polypeptides in plants. Members of the cLE family play critical roles in mediating cell fate decisions during plant development, particularly within the unique meristem structures that contain stem cell reservoirs acting as sources of cells for continuous organ formation. here we review the roles of cLE family members in regulating the activity of the shoot apical meristems that generate the aerial parts of the plants, and of the vascular meristems that produce the sugar- and water-conducting tissues. A systematic literature search was performed using the Google Scholar and PubMed search engines. The keywords “cLE”, “cLV3”, “TDIF”, “meristem”, and “plant stem cells” were used as search terms. The 95 retrieved articles, dating from 1992, were organized by topic and their key findings incorporated into the text. We summarize our current understanding of how the cLE peptide cLV3 orchestrates the activity of shoot apical meristems, describing its expression, processing and movement, as well as its intracellular signal transduction pathways, key target genes and downstream gene regulatory networks. We also discuss the roles of cLE peptide signaling in the vascular meristems to promote procambial cell proliferation and suppress xylem differentiation. Signaling pathways mediated by cLE peptides are critical for stem cell maintenance and differentiation in shoot apical and vascular me

关键词： cLE cLV3 TDIF WUS stem cells procambium

SYNTheSIS AND IDENTIFIcATION OF cONDUcTING POLYANILINE DOPED WITH RARE EARTH cHLORIDE

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Acta Metallurgica Sinica(English Letters) 2000年第3期13卷 872-876页

作者： Yang, c.M. Zhang, q.R. Fang, Z. central South Univ of Technology Changsha China

Polyaniline doped with rare earth chloride was synthesized in organic solvent and identified by elemental analysis and infrared spectroscopy. The experimental results show that there exists both doping and complexation at the same time in the resulting product. When pH4. Moreover, polyaniline doped with rare earth chloride exhibits better thermal stability than that doped with hydrochloric acid.

关键词： chlorine compounds composition conductive materials Electric conductivity Organic polymers Rare earth compounds Synthesis (chemical)

EVOLUTION OF MIcROSTRUcTURE OF Sn-Ag-cu LEAD-FREE FLIP cHIP SOLDER JOINTS DURING AGING PROcESS

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Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 301-306页

作者： Y.H. Tian c.q. Wang W.F. Zhou State Key Lab of Advanced Welding Production and Technology Harbin Institute of Technology Harbin 150001 China

Flip chip bonding has become a primary technology that has found application in the chip interconnection process in the electronic manufacturing industry in recent years. The solder joints of the flip chip bonding are small and consist of complicated microstructures such as Sn solution, eutectic mixture, and intermetallic compounds （IMcs）, whose mechanical performance is quite different from the original solder bulk. The evolution of microstructure of the flip chip solder joints under thermal aging was analyzed. The results show that with an increase in aging time, coarsening of solder bulk matrix and AuSn4 IMcs occurred within the solder. The IMcs that are formed at the bottom side of the flip chip bond were different from those on the top side during the aging process. （cu, Ni, Au）0Sn5 were formed at the interfaces of both sides, and large complicated （Au,Ni, cu）Sn4 IMcs appeared for some time near the bottom interface after aging, but they disappeared again and thus （cu,Ni, Au ）0Sn5 IMc thickness increased considerably. The influence of reflow times during the flip chip bonding （as-bonded condition） on the characteristics of interfacial IMcs was weakened when subjected to the aging process.

关键词： lead free solder flip chip aging

STUDY The INFLUENcE OF H_(3)BO_(3)ON The ZINc ELEcTROPLATING USING ELEcTROcheMIcAL NOISE TEcHNIqUE

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 661-666页

作者： Z.Zhang c.S.Wu q.Y.cai Y.L.cheng F.H.cao J.q.Zhang c.N.cao Departmentofchemistry ZhejiangUniversityHangzhou310027China StateKeyLaboratoryforcorrosionandProtection InstituteofMetalResearchTheChineseAcademyofSciencesShenyang110016China

The influence of H3BO3 on the zinc electroplating was studied using electrochemical noise technique, cyclic voltammetry and steady-state polarization method. The results showed that, under the experimental conditions, the deposition of zinc followed the mechanism of two-dimensional nucleation and subsequent grain growth. The addition of H3BO3 into the electroplating solution prominently changes the nucleation and growth kinetics of zinc deposits, which is directly related to the features of electrocrystallization noise and the corresponding structure of the electrodeposits. The results also shown that the electrochemical noise (EN) technique can give more information about the electrodeposits structure and electroplating mechanism than other normal electrochemical measurements can give, such as steady-state polarization method and cyclic voltammetry technique.

关键词： zinc electroplating electrochemical noise electrocrystallization

Overexpression of Arabidopsis Sorting Nexin AtSNX2b Inhibits Endocytic Trafficking to the Vacuole

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Molecular Plant 2008年第6期1卷 961-976页

作者： Nguyen q. Phan Department of Genetics Development and Cell Biology Iowa State University Ames IA 50011 USA Interdepartmental Genetics Program Iowa State University Ames IA 50011 USA Plant Sciences Institute Iowa State University Ames IA 50011 USA

Sorting nexins are conserved proteins that function in vesicular trafficking and contain a characteristic phox homology （PX） domain. here, we characterize the ubiquitously expressed Arabidopsis thaliana sorting nexin AtSNX2b. Sub-cellular fractionation studies indicate that AtSNX2b is peripherally associated with membranes. The AtSNX2b PX domain binds to phosphatidylinositol 3-phosphate in vitro and this association is required for the localization of GFPAtSNX2b to punctate structures in vivo, identified as the trans-Golgi network, prevacuolar compartment and endosomes. Overexpression of GFP-tagged AtSNX2b produces enlarged GFP-labeled compartments that can also be labeled by the endocytic tracer FM4-64. Endocytic trafficking of FM4-64 to the vacuole is arrested in these GFP-AtSNX2b compartments, and similar FM4-64-accumulating compartments are seen upon overexpression of untagged AtSNX2b. This suggests that exit of membrane components from these enlarged or aggregated endosomes is inhibited. Vacuolar proteins containing an N-terminal propeptide, but not those with a c-terminal propeptide, are also present in these enlarged compartments. We hypothesize that AtSNX2b is involved in vesicular trafficking from endosomes to the vacuole.

关键词： phox homology Overexpression Vacuole

DEcREASING PITTING SUScEPTIBILITY OF PASSIVE FILMS ON X70 PIPELINE STEEL IN Nacl SOLUTIONS BY ILLUMINATION

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Acta Metallurgica Sinica(English Letters) 2006年第2期19卷 91-97页

作者： W.c. Zhu W.H. Leng J.q. Zhang c.N. cao Department of chemistry Zhejiang University Hangzhou 310027 China State Key Laboratory for corrosion and Protection of Metals Institute of Metal Research The Chinese Academy of Sciences Shenyang 110016 China

The influence of UV illumination on passivity and pitting susceptibility on X70 pipoeline steel in a borate buffer （pH=8.4 ） solution containing Nacl is described. It is observed that illumination of the sample leads to a decrease in its pitting susceptibility as indicated by pitting potential and incubation time measurements in chloride containing electrolytes. This effect is strongly dependent on the applied potential during passivation. The electronic properties of the passive films on X70 steel were studied by Mott-Schottky analysis and photocurrent transient measurements. The results indicated that illumination during passivation led to modifications in the electronic properties of the passive films, mainly to a decrease of the bulk doping and an increase in the surface state density. The cause for the decrease in the pitting susceptibility is preliminary explained in terms of such modifications of the passive flm.

关键词： X70 pipeline steel pitting susceptibility illumination passivation

Synthesis of Polynorbornene-Poly(ethylene-co-propylene)Diblock copolymer

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chinese chemical Letters 1998年第5期9卷 447-450页

作者： Wu, q Wen, q Lu, ZJ Zhongshan Univ Inst Polymer Sci Canton 510275 Peoples R China

Transformation of living ring-opening metathesis polymerization into coordination polymerization by converting the titanacyclobutane group attached to a polynorbornene chain into titanocene alkoxide has been used for the synthesis of polynorbornene-poly(ethylene-co-propylene) block copolymer. Preliminary characterizations of the copolymerization products by solvent extraction and c-13 NMR spectrum are reported.

关键词： ring-opening metathesis polymerization coordination polymerization diblock copolymer norbornene ethylene propylene

Effects of chemical pressure on diluted magneticsemiconductor(Ba,K)(Zn,Mn)_2As_2

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chinese Physics B 2019年第5期28卷 288-292页

作者： Y Peng S Yu G q Zhao W M Li J F Zhao L P cao X c Wang q q Liu S J Zhang R Z Yu Z Deng X H Zhu c q Jin college of Materials Science & Engineering Sichuan University Beijing National Laboratory for condensed Matter Physics and Institute of Physics Chinese Academy of Sciences School of Physics University of Chinese Academy of Sciences collaborative Innovation center of quantum Matter

chemical pressure induced by iso-valent doping has been widely employed to tune physical properties of materials. In this work, we report effects of chemical pressure by substitution of Sb or P into As on a recently discovered diluted magnetic semiconductor(Ba,K)(Zn,Mn)_2 As_2, which has the record of reliable curie temperature of 230 K due to independent charge and spin doping. Sb and P are substituted into As-site to produce negative and positive chemical pressures, respectively.X-ray diffraction results demonstrate the successful chemical solution of dopants. Magnetic properties of both K-underdoped and K-optimal-doped samples are effectively tuned by Sb-and P-doping. The Hall effect measurements do not show decrease in carrier concentrations upon Sb-and P-doping. Impressively, magnetoresistance is significantly improved from7% to 27% by only 10% P-doping, successfully extending potential application of(Ba,K)(Zn,Mn)_2 As_2.

关键词： chemical pressure (Ba,K)(Zn,Mn)2As2 diluted magnetic semiconductor iso-valent doping

Electron tomography for sintered ceramic materials by a neural network algebraic reconstruction technique

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Journal of Materials Science & Technology 2022年第5期100卷 75-81页

作者： R.H.Shen Y.T.he W.q.Ming Y.Zhang X.D.Xu J.H.chen centre for High Resolution Electron Microscopy College of Materials Science and EngineeringHunan UniversityChangsha 410082China

The missing wedge effect in electron tomography introduces various types of artifacts in the tomograms and lowers the reconstruction resolution and *** artifacts produced in tomographic reconstruction of bulk materials can be very severe,particularly for sintered bulk ceramic materials in which there are often nano-pores or pore-like microstructure ***,we report a neural network algebraic reconstruction algorithm with no prior knowledge to perform electron tomography for a sintered Sic material with nano carbon *** results show that the proposed algorithm has a great suppressive effect on the missing wedge artifacts and a high tolerance for *** information in the missing wedge can be partly recovered by this ***,both the shape of the bulk Sic specimen and its irregular inner pore-like features are correctly retrieved in the obtained 3D *** study shows the effectiveness of the neural network algorithm for improving the reconstruction accuracy of electron tomography,in order to reveal sophisticated 3D microstructures generally existing in sintered ceramic materials.

关键词： Neural network Missing wedge Electron tomography Sintered ceramics