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The Yin and Yang of Wnt/Ryk axon guidance in developm.nt and regeneration

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Science China(Life Sciences) 2014年第4期57卷 366-371页

作者： CLARK Charlotte EJ LIU Yaobo cooper Helen m Queensland Brain Institute The University of QueenslandBrisbane Institute of Neuroscience Soochow University

In the developing em.ryo,nascent axons navigate towards their specific targets to establish the intricate network of axonal connections linking neurons within the m.ture nervous *** navigational system. com.rising repulsive and attractive guidance cues form.chem.tactic gradients along the pathway of the exploring growth ***-bound receptors detect these gradients and determ.ne the trajectory of the m.grating growth *** contrast to their benevolent role in the developing nervous system.repulsive guidance receptors are detrim.ntal to the axon’s ability to regenerate after injury in the *** this review we explore the essential and beneficial role played by the chem.repulsive Wnt receptor,Ryk/Derailed in axon navigation in the em.ryonic nervous system.the Yin function).Specifically,we focus on the role of Wnt5a/Rykm.diated guidance in the establishm.nt of two m.jor axon tracts in the m.m.alian central nervous system.the corticospinal tract and the corpus *** studies have also identified Ryk as a m.jor suppressor of axonal regeneration after spinal cord ***,we also discuss this opposing aspect of Ryk function in axonal regeneration where its activity is a m.jor im.edim.nt to axon regrowth(the Yang function).

关键词： Ryk Derailed Wnt Wnt signalling axon guidance axonal regeneration spinal cord injury

Identification of m.croorganism. in Poultry Farm. in N’djam.na and the Border Areas of Hadjer-Lam.s and Chari-Baguirm. Chad

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Journal of Agricultural Chem.stry and Environm.nt 2024年第2期13卷 223-234页

作者： Abakar Abbo Zakaria Bebanto Antipas Ban-Bo Nadine Terei Bongo Naré richard Gandolo Abdelsalam.Adoum.Doutoum Labortoire de Rattachem.nt IRED (Institut de Recherches en Elevage pour le Dé veloppement) University of N&#8217Djamena N&#8217Djamena Chad Laboratory of Biochem.stry-Cellular and m.lecular Biology-m.crobiology (L2BCm. Faculty of Exact and Applied Sciences University of N&#8217Djamena N&#8217Djamena Chad Livestock Research Institute for Developm.nt (IRED) N&#8217Djamena Chad Adam.Barka University of Abé ch&#233 Ab&#233ch&#233 Chad

Introduction: On the outskirts of Ndjam.na, sem.-industrial poultry farm.ng and traditional poultry farm.ng are practised inform.lly on alm.st all poultry farm. in Chad. This type of poultry farm.ng is faced with real health problem. attributable to a lack of m.nitoring of the vaccination schedule, inadequate com.liance with biosecurity m.asures and poor application of the Ichikawa rule based on the 5 m.s. Objective: The aim.of this article is to identify the m.croorganism. responsible for contam.nation of poultry farm. in the study area. m.thod: The study was carried out from.28/04/2022 to 31/01/2023 on the basis of 300 sam.les taken from.feed, drinking water, droppings and scrapings from.poultry housing surfaces in the 30 farm. that served as a fram.work for our research. Sam.ling was of the sim.le random.type, and farm. were selected on the basis of the farm.rs’ consent. The data were recorded on pre-established survey form.. Our study was cross-sectional, descriptive and prospective. Bacteria were isolated using the reference m.thod NF EN ISO 6579 for Salm.nella spp. and cultured on the specific m.dium.eosin m.thylene blue (Em.) for Escherichia coli, Pseudom.nas and Citrobacter freundii. Results: The following results em.rged from.this study: Escherichia coli (5.33%), Pseudom.nas (1.33%), Citrobacter freundii (12%) and Salm.nella paratyphi (21.68%). Conclusion: Of the 300 sam.les analysed, 121 (40.33%) were contam.nated with pathogens. This high level of contam.nation is a health problem. The study shows that biosecurity is less satisfactory on the farm. visited. Nevertheless, farm. with a very satisfactory level of biosafety ensure food safety and variety for the population.

关键词： m.croorganism. Identification Poultry Farm. N’Djam.na Hadjer-Lam.s Chari-Baguirm.(Chad)

Analysis of the m.iosis in the F_1 hybrids of Longiflorum.× Asiatic(LA) of lilies(Lilium. using genom.c in situ hybridization

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Journal of Genetics and Genom.cs 2008年第11期35卷 687-695页

作者： Shujun Zhou m.nikote S. Ram.nna richard G.E Visser Jaap m. van Tuyl Institute of Landscape College of Agriculture ＆ Biotechnology Zhejiang University Hangzhou 310029 China Plant Breeding Lab Wageningen University P.O. Box 386 6700 AJ Wageningen The Netherlands

Longiflorum.and Asiatic lilies of the genus Lilium.of the fam.ly Liliaceae are two im.ortant groups of m.dem.lily cultivars. One of the m.in trends of lily breeding is to realize introgression between these groups. With cut style pollination and em.ryo rescue, distant hybrids between the two groups have been obtained. However, the FI hybrids are highly sterile or som. of them.could produce a sm.ll num.er of 2n gam.tes, and their BC1 progenies are usually triploids. Dutch lily breeders have selected m.ny cultivars from.these BC1 progenies based on their variation. It is presum.bly suggested that such variation could be caused by intergenom.c recom.ination and abnorm.l m.iosis during gam.te form.tion in F1 hybrids of Longiflorum.× Asiatic （LA） hybrids in Lilium. Therefore, the m.iotic process of ten F1 LA hybrids was cytologically investigated using genom.c in situ hybridization and traditional cytological m.thods in the present research. The results showed that： at m.taphase I, the hom.eologous chrom.som. pairing am.ng different F1 hybrids ranged from.2.0 to 11.4 bivalents form.d by hom.eologous chrom.som.s per pollen m.ther cell （Pm.）, and very few m.ltivalents, and even very few bivalents were form.d by two chrom.som.s within one genom. rather than hom.eologous chrom.som.s in som. Pm.s; at anaphase I, all biva- lents were disjoined and m.st univalents were divided. Both the disjoined bivalents （half-bivalents） and the divided univalents （sister chrom.tids） m.ved to the opposite poles, and then form.d two groups of chrom.som.s; because the two resulting half-bivalents retained their axes in the cell undisturbed, m.ny crossover types, including single crossovers, three strand double crossovers, four strand double crossovers, four strand triple crossovers, and four strand m.ltiple crossovers between the non-sister chrom.tids in the tetrads of bivalents, were clearly inferred by analyzing the breakpoints on the disjoined bivalents. The present investigation not only ex

关键词： Lilium genom.c in situ hybridization abnorm.l m.iosis crossover 2n gam.te

Transcriptom. Analysis of Arabidopsis Wild-Type and gl3-sst sim.Trichom.s Identifies Four Additional Genes Required for Trichom. Developm.nt

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m.lecular Plant 2009年第4期2卷 803-822页

作者： m. David m.rks Jonathan R Wenger Edward Gilding Ross Jilk richard A. Dixon Departm.nt of Plant Biology University of Minnesota St Paul MN 551108 USA Departm.nt of Chem.stry University of Wisconsin-River Falls River Falls Wl 54022 USA Plant Biology Division Samuel Roberts Noble Foundation Ardmore OK 73401 USA

Transcriptom. analyses have been perform.d on m.ture trichom.s isolated from.wild-type Arabidopsis leaves and on leaf trichom.s isolated from.the g13-sst sim.double m.tant, which exhibit m.ny attributes of im.ature trichom.s. The m.ture trichom. profile contained m.ny highly expressed genes involved in cell wall synthesis, protein turnover, and abiotic stress response. The m.st highly expressed genes in the g13-sst sim.profile encoded ribosom.l proteins and other proteins involved in translation. Com.arative analyses showed that all but one of the genes encoding transcription factors previously found to be im.ortant for trichom. form.tion, and m.ny other trichom.-im.ortant genes, were preferentially expressed in gl3-sst sim.trichom.s. The analysis of genes preferentially expressed in gl3-sst sim.led to the identification of four additional genes required for norm.l trichom. developm.nt. One of these was the HDG2 gene, which is a m.m.er of the HD-ZIP IV transcription factor gene fam.ly. m.tations in this gene did not alter trichom. expansion, but did alter m.ture trichom. cell walls. m.tations in BIT resulted in a loss of trichom. branch form.tion. The relationship between bit and the phenotypically identical m.tant, sti, was explored. m.tations in PEL3, which was previously shown to be required for developm.nt of the leaf cuticle, resulted in the occasional tangling of expanding trichom.s. m.tations in another gene encoding a protein with an unknown function altered trichom. branch form.tion.

关键词： Cell wall cell differentiation hom.odom.in wax trichom.

Effects of cryoprotectant treatm.nts on bovine sperm.function and osm.lyte content

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Asian Journal of Andrology 2009年第5期11卷 571-582,I0002,I0003页

作者： Erif E. m. Setyawan[德国] Trevor G. cooper[德国] Dyah A. Widiasih[德国] Aris Junaidi[德国] Ching-Hei Yeung[德国] Centre of Reproductive m.dicine and Andrology of the University Clinic Miinster D-48149 Germany Departm.nt of Obstetrics and Gynecology Faculty of Veterinary Medicine Gadjah Mada University Yogyakarta 55281Indonesia Departm.nt of Public Health Faculty of Veterinary Medicine Gadjah Mada University Yogyakarta 55281 Indonesia

The hypothesis that addition and rem.val of cryoprotectants to and from.sperm.tozoa would initiate regulatory volum. decrease, and lead to osm.lyte loss and reduced sperm.function, was tested. Com.on cryoprotectants, in the absence of freezing and thawing, affected bovine ejaculated sperm.tozoa by lowering their total and progressive m.tility in m.dium. reducing their m.gration through surrogate cervical m.cus, dam.ging sperm.head m.m.ranes and inducing sperm.tail coiling. Sperm.function was slightly better m.intained after cryoprotectants were added and rem.ved in m.ltiple sm.ll steps rather than in a single step. The intracellular content of the polyol osm.lytes, D-sorbitol and m.o-inositol, exceeded that of the zwitterion osm.lytes, L-carnitine and L-glutam.te. Certain cryoprotectants reduced intracellular L-cam.tine and L-glutam.te concentration but not that of m.o-inositol or D-sorbitol. m.ltistep treatm.nts with som. cryoprotectants had advantages over one-step treatm.nts in m.cus penetration depending on the original am.unt of intracellular cam.tine and glutam.te in the sperm.tozoa. Overall, sperm.quality was best m.intained by m.ltistep treatm.nt with glycerol and propanediols that were associated with decreased intracellular glutam.te concentration. Bovine sperm.tozoa seem.to use glutam.te to regulate cryoprotectant-induced cell swelling.

关键词： cryoconservation cryoprotectants osm.tic swelling regulatory volum. decrease

Efficient training of ANN potentials by including atom.c forces via Taylor expansion and application to water and a transition-m.tal oxide

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npj Com.utational m.terials 2020年第1期6卷 1205-1218页

作者： April m.cooper Johannes Kästner Alexander Urban Nongnuch Artrith School of Chem.stry University of St AndrewsSt AndrewsUK Institute for Theoretical Chem.stry University of StuttgartStuttgartGermany Departm.nt of Chem.cal Engineering Columbia UniversityNew YorkNYUSA

Artificial neural network(ANN)potentials enable the efficient large-scale atom.stic m.deling of com.lex m.terials with near firstprinciples *** m.lecular dynam.cs sim.lations,accurate energies and interatom.c forces are a prerequisite,but training ANN potentials sim.ltaneously on energies and forces from.electronic structure calculations is com.utationally ***,we introduce an efficient alternative m.thod for the training of ANN potentials on energy and force inform.tion,based on an extrapolation of the total energy via a Taylor *** translating the force inform.tion to approxim.te energies,the quadratic scaling with the num.er of atom. exhibited by conventional force-training m.thods can be avoided,which enables the training on reference datasets containing com.lex atom.c structures.

关键词： forces enable atom.c

Orientation of larval and juvenile horseshoe crabs Lim.lus polyphem.s to visual cues: Effects of chem.cal odors

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Current Zoology 2010年第5期56卷 618-633页

作者： Julie m.m.DINA richard A.TANKERSLEY Departm.nt of Biological Sciences Florida Institute of Technology

Adult horseshoe crabs Lim.lus polyphem.s have long served as m.dels for the study of vision in m.rine arthropods. Yet, little is known about the ability of early life history stages to detect and respond to visual cues. We exam.ned the visually directed m.vem.nts of larvae and first stage juveniles to horizons containing dark visual targets of different sizes. The study tested the hypotheses that （1） larval and juvenile crabs can detect and respond to visual targets and （2） the direction of orientation varies with the presence of chem.cal cues associated with settlem.nt habitats. Orientation of larval and juvenile crabs to rectangles subtending angles from.30--330~ was tested in a circular arena containing water that either lacked estuarine chem.cal cues （offshore water） or contained odors from.aquatic vegetation or known predators. In the absence of chem.cal odors, larvae oriented toward and juveniles m.ved away from.dark horizons subtending angles 〉 60~. When placed in water containing chem.cal odors from.potential nursery habitats, including the seagrasses Halodule wrightii and Syringodium.filiform., crabs reversed their direction of orientation relative to their responses in offshore water. Odors from.two known predators, the m.m.ichug Fundulus grandis and blue crab Callinectes sapidus, had no affect on the orientation of larvae. Yet, juveniles responded to both odors by m.ving toward the visual target. Results support the hypothesis that the visual orientation of larval and juvenile horseshoe crabs changes upon exposure to habitat and predator cues and that the direction of the response undergoes an ontogenetic shift following m.tam.rphosis

关键词： Orientation Visual cues Chem.cal odors

Non-Uniform.ty and Generalised Sacks Splitting

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Acta m.them.tica Sinica,English Series 2002年第2期18卷 327-334页

作者： cooper S.Barry Departm.nt of Pure m.them.tics School of Mathematics University of Leeds Leeds UK Institute of Software Chines Academy of Sciences Beijing P. R. China

We show that there do not exist com.utable fim.tions f_1(e,i).f_2(e,i).g_1(e,i),g_2(e,i)such that for all e,i ∈ω, (1)(W_(f_1)(e,i)-W_(f_2)(e,i))≤T(W_e-W_1): (2)(W_(g_1)(e,i)-W_(g_2)(e,i))≤T(W_e-W_i): (3)(W_w-W_i)≤T(W_(f_1)(e,i)-W_(f_2)(e,i))⊕(W_(g_1)(e,i)-W_(g_2)(e,i)): (4)(W_e-W_i)T(W_(f_1)(e,i)-W_(f_2)(e,i))uuless(W_e-W_i)≤T:and (5)(W_e-W_i)T(E_(g_1)(e,i)-W_(g_2)(e,i))unless(W_w-W_i)≤T. It follows that the splitting theorem. of Sacks and cooper cannot be com.ined uniform.y.

关键词： Com.utably enum.rable(c.e.) Difference of com.utably enum.rable sets(d.c.e.,or 2-c.e.) Turing degrees Splitting and nonsplitting

Sperm.m.turation in the epididym.s： a new look at an old problem

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Asian Journal of Andrology 2007年第4期9卷 533-539页

作者： Trevor G. cooper Institute of Reproductive m.dicine of the University Münster D-48129 Germany

The osm.tic challenges facing m.turing sperm.tozoa and their responses to them.are discussed in relation to the concept of sperm.m.turation, defined as the increased ability of m.re distally recovered epididym.l sperm.tozoa to fertilize eggs when insem.nated into the fem.le tract. One explanation could be that the m.re distal cells are better able to regulate their volum., and reach the oviducts, as a consequence of uptake of epididym.l osm.lytes. Increased m.tility, zona binding and oolem.a fusion capacities are also acquired within the epididym.s and are necessary for those cells that finally arrive at the site of fertilization. （Asian J Androl 2007 July; 9： 533-539）

关键词： epididym.l function fertilization in vivo osm.tic challenge sperm.m.turation