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1
Leonard, Carrie E., Maryna Baydyuk, Marissa A. Stepler, Denver A. Burton, and Maria J. Donoghue. "EphA7 isoforms differentially regulate cortical dendrite development." PLOS ONE 15, no. 12 (2020): e0231561. http://dx.doi.org/10.1371/journal.pone.0231561.
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The shape of a neuron facilitates its functionality within neural circuits. Dendrites integrate incoming signals from axons, receiving excitatory input onto small protrusions called dendritic spines. Therefore, understanding dendritic growth and development is fundamental for discerning neural function. We previously demonstrated that EphA7 receptor signaling during cortical development impacts dendrites in two ways: EphA7 restricts dendritic growth early and promotes dendritic spine formation later. Here, the molecular basis for this shift in EphA7 function is defined. Expression analyses reveal that EphA7 full-length (EphA7-FL) and truncated (EphA7-T1; lacking kinase domain) isoforms are dynamically expressed in the developing cortex. Peak expression of EphA7-FL overlaps with dendritic elaboration around birth, while highest expression of EphA7-T1 coincides with dendritic spine formation in early postnatal life. Overexpression studies in cultured neurons demonstrate that EphA7-FL inhibits both dendritic growth and spine formation, while EphA7-T1 increases spine density. Furthermore, signaling downstream of EphA7 shifts during development, such that in vivo inhibition of mTOR by rapamycin in EphA7-mutant neurons ameliorates dendritic branching, but not dendritic spine phenotypes. Finally, direct interaction between EphA7-FL and EphA7-T1 is demonstrated in cultured cells, which results in reduction of EphA7-FL phosphorylation. In cortex, both isoforms are colocalized to synaptic fractions and both transcripts are expressed together within individual neurons, supporting a model where EphA7-T1 modulates EphA7-FL repulsive signaling during development. Thus, the divergent functions of EphA7 during cortical dendrite development are explained by the presence of two variants of the receptor.
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Ehlers, Michael D. "Dendrite development." Journal of Cell Biology 170, no. 4 (2005): 517–19. http://dx.doi.org/10.1083/jcb.200507096.
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Kalb, R. G. "Regulation of motor neuron dendrite growth by NMDA receptor activation." Development 120, no. 11 (1994): 3063–71. http://dx.doi.org/10.1242/dev.120.11.3063.
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Spinal motor neurons undergo great changes in morphology, electrophysiology and molecular composition during development. Some of this maturation occurs postnatally when limbs are employed for locomotion, suggesting that neuronal activity may influence motor neuron development. To identify features of motor neurons that might be regulated by activity we first examined the structural development of the rat motor neuron cell body and dendritic tree labeled with cholera toxin-conjugated horseradish peroxidase. The motor neuron cell body and dendrites in the radial and rostrocaudal axes grew progressively over the first month of life. In contrast, the growth of the dendritic arbor/cell and number of dendritic branches was biphasic with overabundant growth followed by regression until the adult pattern was achieved. We next examined the influence of neurotransmission on the development of these motor neuron features. We found that antagonism of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor inhibited cell body growth and dendritic branching in early postnatal life but had no effect on the maximal extent of dendrite growth in the radial and rostrocaudal axes. The effects of NMDA receptor antagonism on motor neurons and their dendrites was temporally restricted; all of our anatomic measures of dendrite structure were resistant to NMDA receptor antagonism in adults. These results suggest that the establishment of mature motor neuron dendritic architecture results in part from dendrite growth in response to afferent input during a sensitive period in early postnatal life.
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Sharp, D. J., W. Yu, and P. W. Baas. "Transport of dendritic microtubules establishes their nonuniform polarity orientation." Journal of Cell Biology 130, no. 1 (1995): 93–103. http://dx.doi.org/10.1083/jcb.130.1.93.
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The immature processes that give rise to both axons and dendrites contain microtubules (MTs) that are uniformly oriented with their plus-ends distal to the cell body, and this pattern is preserved in the developing axon. In contrast, developing dendrites gradually acquire nonuniform MT polarity orientation due to the addition of a subpopulation of oppositely oriented MTs (Baas, P. W., M. M. Black, and G. A. Banker. 1989. J. Cell Biol. 109:3085-3094). In theory, these minus-end-distal MTs could be locally nucleated and assembled within the dendrite itself, or could be transported into the dendrite after their nucleation within the cell body. To distinguish between these possibilities, we exposed cultured hippocampal neurons to nanomolar levels of vinblastine after one of the immature processes had developed into the axon but before the others had become dendrites. At these levels, vinblastine acts as a kinetic stabilizer of MTs, inhibiting further assembly while not substantially depolymerizing existing MTs. This treatment did not abolish dendritic differentiation, which occurred in timely fashion over the next two to three days. The resulting dendrites were flatter and shorter than controls, but were identifiable by their ultrastructure, chemical composition, and thickened tapering morphology. The growth of these dendrites was accompanied by a diminution of MTs from the cell body, indicating a net transfer of MTs from one compartment into the other. During this time, minus-end-distal microtubules arose in the experimental dendrites, indicating that new MT assembly is not required for the acquisition of nonuniform MT polarity orientation in the dendrite. Minus-end-distal microtubules predominated in the more proximal region of experimental dendrites, indicating that most of the MTs at this stage of development are transported into the dendrite with their minus-ends leading. These observations indicate that transport of MTs from the cell body is an essential feature of dendritic development, and that this transport establishes the nonuniform polarity orientation of MTs in the dendrite.
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Ligon, Cheryl, Eunju Seong, Ethan J. Schroeder та ін. "δ-Catenin engages the autophagy pathway to sculpt the developing dendritic arbor". Journal of Biological Chemistry 295, № 32 (2020): 10988–1001. http://dx.doi.org/10.1074/jbc.ra120.013058.
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The development of the dendritic arbor in pyramidal neurons is critical for neural circuit function. Here, we uncovered a pathway in which δ-catenin, a component of the cadherin–catenin cell adhesion complex, promotes coordination of growth among individual dendrites and engages the autophagy mechanism to sculpt the developing dendritic arbor. Using a rat primary neuron model, time-lapse imaging, immunohistochemistry, and confocal microscopy, we found that apical and basolateral dendrites are coordinately sculpted during development. Loss or knockdown of δ-catenin uncoupled this coordination, leading to retraction of the apical dendrite without altering basolateral dendrite dynamics. Autophagy is a key cellular pathway that allows degradation of cellular components. We observed that the impairment of the dendritic arbor resulting from δ-catenin knockdown could be reversed by knockdown of autophagy-related 7 (ATG7), a component of the autophagy machinery. We propose that δ-catenin regulates the dendritic arbor by coordinating the dynamics of individual dendrites and that the autophagy mechanism may be leveraged by δ-catenin and other effectors to sculpt the developing dendritic arbor. Our findings have implications for the management of neurological disorders, such as autism and intellectual disability, that are characterized by dendritic aberrations.
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Ybarra, Natividad, Peter J. Hemond, Michael P. O'Boyle, and Kelly J. Suter. "Spatially Selective, Testosterone-Independent Remodeling of Dendrites in Gonadotropin-Releasing Hormone (GnRH) Neurons Prepubertally in Male Rats." Endocrinology 152, no. 5 (2011): 2011–19. http://dx.doi.org/10.1210/en.2010-0871.
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Adult GnRH neurons exhibit a stereotypic morphology with a small soma, single axon, and single dendrite arising from the soma with little branching. The adult morphology of GnRH neurons in mice reflects an anatomical consolidation of dendrites over postnatal development. We examined this issue in rat GnRH neurons with biocytin filling in live hypothalamic slices from infant males, as adult littermates and in gonad-intact males, castrated males, and in males with one of three levels of testosterone (T) treatment. Somatic area and total dendritic length were significantly greater in infant males than in adults. Moreover, total numbers of dendrite branches were greater in infant males as compared with adults. The number of higher order branches and the lengths of higher order branches were also greater in infant males than in adults. Most interestingly, in adults a single dendrite arose from the somata, consistently at 180° from the axon. In contrast, prepubertal animals had an average of 2.2 ± 0.2 primary dendrites arising from somata (range, one to seven primary dendrites). Angles relative to the axon at which dendrites in prepubertal males emanated from GnRH somata were highly variable. Castration at 25 d of age and castration at 25 d of age with one of three levels of T treatment did not influence morphological parameters when GnRH neurons were examined between 40 d and 48 d of age. Thus, a spatially selective remodeling of primary dendrites and consolidation of distal GnRH dendritic arbors occurs during postnatal development and is largely independent of T.
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Takano, Tetsuya, Tomoki Urushibara, Nozomu Yoshioka, et al. "LMTK1 regulates dendritic formation by regulating movement of Rab11A-positive endosomes." Molecular Biology of the Cell 25, no. 11 (2014): 1755–68. http://dx.doi.org/10.1091/mbc.e14-01-0675.
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Neurons extend two types of neurites—axons and dendrites—that differ in structure and function. Although it is well understood that the cytoskeleton plays a pivotal role in neurite differentiation and extension, the mechanisms by which membrane components are supplied to growing axons or dendrites is largely unknown. We previously reported that the membrane supply to axons is regulated by lemur kinase 1 (LMTK1) through Rab11A-positive endosomes. Here we investigate the role of LMTK1 in dendrite formation. Down-regulation of LMTK1 increases dendrite growth and branching of cerebral cortical neurons in vitro and in vivo. LMTK1 knockout significantly enhances the prevalence, velocity, and run length of anterograde movement of Rab11A-positive endosomes to levels similar to those expressing constitutively active Rab11A-Q70L. Rab11A-positive endosome dynamics also increases in the cell body and growth cone of LMTK1-deficient neurons. Moreover, a nonphosphorylatable LMTK1 mutant (Ser34Ala, a Cdk5 phosphorylation site) dramatically promotes dendrite growth. Thus LMTK1 negatively controls dendritic formation by regulating Rab11A-positive endosomal trafficking in a Cdk5-dependent manner, indicating the Cdk5-LMTK1-Rab11A pathway as a regulatory mechanism of dendrite development as well as axon outgrowth.
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Feng, Chengye, Pankajam Thyagarajan, Matthew Shorey, et al. "Patronin-mediated minus end growth is required for dendritic microtubule polarity." Journal of Cell Biology 218, no. 7 (2019): 2309–28. http://dx.doi.org/10.1083/jcb.201810155.
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Microtubule minus ends are thought to be stable in cells. Surprisingly, in Drosophila and zebrafish neurons, we observed persistent minus end growth, with runs lasting over 10 min. In Drosophila, extended minus end growth depended on Patronin, and Patronin reduction disrupted dendritic minus-end-out polarity. In fly dendrites, microtubule nucleation sites localize at dendrite branch points. Therefore, we hypothesized minus end growth might be particularly important beyond branch points. Distal dendrites have mixed polarity, and reduction of Patronin lowered the number of minus-end-out microtubules. More strikingly, extra Patronin made terminal dendrites almost completely minus-end-out, indicating low Patronin normally limits minus-end-out microtubules. To determine whether minus end growth populated new dendrites with microtubules, we analyzed dendrite development and regeneration. Minus ends extended into growing dendrites in the presence of Patronin. In sum, our data suggest that Patronin facilitates sustained microtubule minus end growth, which is critical for populating dendrites with minus-end-out microtubules.
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Grueber, Wesley B., Lily Y. Jan, and Yuh Nung Jan. "Tiling of the Drosophila epidermis by multidendritic sensory neurons." Development 129, no. 12 (2002): 2867–78. http://dx.doi.org/10.1242/dev.129.12.2867.
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Insect dendritic arborization (da) neurons provide an opportunity to examine how diverse dendrite morphologies and dendritic territories are established during development. We have examined the morphologies of Drosophila da neurons by using the MARCM (mosaic analysis with a repressible cell marker) system. We show that each of the 15 neurons per abdominal hemisegment spread dendrites to characteristic regions of the epidermis. We place these neurons into four distinct morphological classes distinguished primarily by their dendrite branching complexities. Some class assignments correlate with known proneural gene requirements as well as with central axonal projections. Our data indicate that cells within two morphological classes partition the body wall into distinct, non-overlapping territorial domains and thus are organized as separate tiled sensory systems. The dendritic domains of cells in different classes, by contrast, can overlap extensively. We have examined the cell-autonomous roles of starry night (stan) (also known as flamingo (fmi)) and sequoia (seq) in tiling. Neurons with these genes mutated generally terminate their dendritic fields at normal locations at the lateral margin and segment border, where they meet or approach the like dendrites of adjacent neurons. However, stan mutant neurons occasionally send sparsely branched processes beyond these territories that could potentially mix with adjacent like dendrites. Together, our data suggest that widespread tiling of the larval body wall involves interactions between growing dendritic processes and as yet unidentified signals that allow avoidance by like dendrites.
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Geisler, Hildegard C., Jos IJkema-Paassen, Johan Westerga, and Albert Gramsbergen. "Vestibular Deprivation and the Development of Dendrite Bundles in the Rat." Neural Plasticity 7, no. 3 (2000): 193–203. http://dx.doi.org/10.1155/np.2000.193.
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Motoneuronal pools of muscles that subserve postural tasks contain dendrite bundles. We investigated in the rat the development of these bundles in the pools of the long back muscles and related this to postural development. Motoneurons and their dendrites were retrogradely labeled by injecting unconjugated cholera toxin subunit B (CTB) into the muscles of 54 normal rats from birth until adulthood and into 18 rats that were vestibularly deprived from the 5th postnatal day (P5). Dendrite bundles coursing in a transverse direction already occurred at P1. From P4, the first longitudinal bundles could be observed, but the major spurt in development occurred between P6 and P9, when conspicuous bundles developed coursing in rostro-caudal and tranverse directions. This is the age when rats become able to stand freely and walk a few steps. Around P20, the dendrite bundles attained their adult characteristics. Vestibular deprivation by plugging both semicircular horizontal canals did not lead to a retarded development of dendrite bundles nor to a changed morphology. This finding is remarkable, as behavioral analysis showed a delay in postural development by about 3 days. We hypothesize that dendrite bundles in the pools of the long back muscles function to synchronize the motoneurons in different spinal cord segments.
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Yu, Wenqian, David J. Sharp, Ryoko Kuriyama, Prabhat Mallik, and Peter W. Baas. "Inhibition of a Mitotic Motor Compromises the Formation of Dendrite-like Processes from Neuroblastoma Cells." Journal of Cell Biology 136, no. 3 (1997): 659–68. http://dx.doi.org/10.1083/jcb.136.3.659.
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Microtubules in the axon are uniformly oriented, while microtubules in the dendrite are nonuniformly oriented. We have proposed that these distinct microtubule polarity patterns may arise from a redistribution of molecular motor proteins previously used for mitosis of the developing neuroblast. To address this issue, we performed studies on neuroblastoma cells that undergo mitosis but also generate short processes during interphase. Some of these processes are similar to axons with regard to their morphology and microtubule polarity pattern, while others are similar to dendrites. Treatment with cAMP or retinoic acid inhibits cell division, with the former promoting the development of the axon-like processes and the latter promoting the development of the dendrite-like processes. During mitosis, the kinesin-related motor termed CHO1/MKLP1 is localized within the spindle midzone where it is thought to transport microtubules of opposite orientation relative to one another. During process formation, CHO1/ MKLP1 becomes concentrated within the dendrite-like processes but is excluded from the axon-like processes. The levels of CHO1/MKLP1 increase in the presence of retinoic acid but decrease in the presence of cAMP, consistent with a role for the protein in dendritic differentiation. Moreover, treatment of the cultures with antisense oligonucleotides to CHO1/MKLP1 compromises the formation of the dendrite-like processes. We speculate that a redistribution of CHO1/MKLP1 is required for the formation of dendrite-like processes, presumably by establishing their characteristic nonuniform microtubule polarity pattern.
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Salama-Cohen, Patricia, María-Ángeles Arévalo, Jochen Meier, Rosemarie Grantyn, and Alfredo Rodríguez-Tébar. "NGF Controls Dendrite Development in Hippocampal Neurons by Binding to p75NTR and Modulating the Cellular Targets of Notch." Molecular Biology of the Cell 16, no. 1 (2005): 339–47. http://dx.doi.org/10.1091/mbc.e04-05-0438.
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Notch and neurotrophins control neuronal shape, but it is not known whether their signaling pathways intersect. Here we report results from hippocampal neuronal cultures that are in support of this possibility. We found that low cell density or blockade of Notch signaling by a soluble Delta-Fc ligand decreased the mRNA levels of the nuclear targets of Notch, the homologues of enhancer-of-split 1 and 5 (Hes1/5). This effect was associated with enhanced sprouting of new dendrites or dendrite branches. In contrast, high cell density or exposure of low-density cultures to NGF increased the Hes1/5 mRNA, reduced the number of primary dendrites and promoted dendrite elongation. The NGF effects on both Hes1/5 expression and dendrite morphology were prevented by p75-antibody (a p75NTR-blocking antibody) or transfection with enhancer-of-split 6 (Hes6), a condition known to suppress Hes activity. Nuclear translocation of NF-kappaB was identified as a link between p75NTR and Hes1/5 because it was required for the up-regulation of these two genes. The convergence of the Notch and p75NTR signaling pathways at the level of Hes1/5 illuminates an unexpected mechanism through which a diffusible factor (NGF) could regulate dendrite growth when cell-cell interaction via Notch is not in action.
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Smrt, Richard D., and Xinyu Zhao. "Epigenetic regulation of neuronal dendrite and dendritic spine development." Frontiers in Biology 5, no. 4 (2010): 304–23. http://dx.doi.org/10.1007/s11515-010-0650-0.
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Sharp, David J., Wenqian Yu, Lotfi Ferhat, Ryoko Kuriyama, David C. Rueger, and Peter W. Baas. "Identification of a Microtubule-associated Motor Protein Essential for Dendritic Differentiation." Journal of Cell Biology 138, no. 4 (1997): 833–43. http://dx.doi.org/10.1083/jcb.138.4.833.
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The quintessential feature of the dendritic microtubule array is its nonuniform pattern of polarity orientation. During the development of the dendrite, a population of plus end–distal microtubules first appears, and these microtubules are subsequently joined by a population of oppositely oriented microtubules. Studies from our laboratory indicate that the latter microtubules are intercalated within the microtubule array by their specific transport from the cell body of the neuron during a critical stage in development (Sharp, D.J., W. Yu, and P.W. Baas. 1995. J. Cell Biol. 130:93– 104). In addition, we have established that the mitotic motor protein termed CHO1/MKLP1 has the appropriate properties to transport microtubules in this manner (Sharp, D.J., R. Kuriyama, and P.W. Baas. 1996. J. Neurosci. 16:4370–4375). In the present study we have sought to determine whether CHO1/MKLP1 continues to be expressed in terminally postmitotic neurons and whether it is required for the establishment of the dendritic microtubule array. In situ hybridization analyses reveal that CHO1/MKLP1 is expressed in postmitotic cultured rat sympathetic and hippocampal neurons. Immunofluorescence analyses indicate that the motor is absent from axons but is enriched in developing dendrites, where it appears as discrete patches associated with the microtubule array. Treatment of the neurons with antisense oligonucleotides to CHO1/MKLP1 suppresses dendritic differentiation, presumably by inhibiting the establishment of their nonuniform microtubule polarity pattern. We conclude that CHO1/MKLP1 transports microtubules from the cell body into the developing dendrite with their minus ends leading, thereby establishing the nonuniform microtubule polarity pattern of the dendrite.
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Giacomini, Caterina, Sameehan Mahajani, Roberta Ruffilli, Roberto Marotta, and Laura Gasparini. "Lamin B1 protein is required for dendrite development in primary mouse cortical neurons." Molecular Biology of the Cell 27, no. 1 (2016): 35–47. http://dx.doi.org/10.1091/mbc.e15-05-0307.
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Lamin B1, a key component of the nuclear lamina, plays an important role in brain development and function. A duplication of the human lamin B1 ( LMNB1) gene has been linked to adult-onset autosomal dominant leukodystrophy, and mouse and human loss-of-function mutations in lamin B1 are susceptibility factors for neural tube defects. In the mouse, experimental ablation of endogenous lamin B1 (Lmnb1) severely impairs embryonic corticogenesis. Here we report that in primary mouse cortical neurons, LMNB1 overexpression reduces axonal outgrowth, whereas deficiency of endogenous Lmnb1 results in aberrant dendritic development. In the absence of Lmnb1, both the length and complexity of dendrites are reduced, and their growth is unresponsive to KCl stimulation. This defective dendritic outgrowth stems from impaired ERK signaling. In Lmnb1-null neurons, ERK is correctly phosphorylated, but phospho-ERK fails to translocate to the nucleus, possibly due to delocalization of nuclear pore complexes (NPCs) at the nuclear envelope. Taken together, these data highlight a previously unrecognized role of lamin B1 in dendrite development of mouse cortical neurons through regulation of nuclear shuttling of specific signaling molecules and NPC distribution.
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Redmond, Lori. "Calcium Signaling in Dendrite Development." Microscopy and Microanalysis 10, S02 (2004): 1470–71. http://dx.doi.org/10.1017/s1431927604884824.
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Jan, Yuh-Nung, and Lily Yeh Jan. "The Control of Dendrite Development." Neuron 40, no. 2 (2003): 229–42. http://dx.doi.org/10.1016/s0896-6273(03)00631-7.
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Hines, P. J. "Neuronal Activity and Dendrite Development." Science Signaling 6, no. 304 (2013): ec295-ec295. http://dx.doi.org/10.1126/scisignal.2004960.
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Mishra, Archana, Boris Knerr, Sónia Paixão, Edgar R. Kramer, and Rüdiger Klein. "The Protein Dendrite Arborization and Synapse Maturation 1 (Dasm-1) Is Dispensable for Dendrite Arborization." Molecular and Cellular Biology 28, no. 8 (2008): 2782–91. http://dx.doi.org/10.1128/mcb.02102-07.
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ABSTRACT The development of a highly branched dendritic tree is essential for the establishment of functional neuronal connections. The evolutionarily conserved immunoglobulin superfamily member, the protein dendrite arborization and synapse maturation 1 (Dasm-1) is thought to play a critical role in dendrite formation of dissociated hippocampal neurons. RNA interference-mediated Dasm-1 knockdown was previously shown to impair dendrite, but not axonal, outgrowth and branching (S. H. Shi, D. N. Cox, D. Wang, L. Y. Jan, and Y. N. Jan, Proc. Natl. Acad. Sci. USA 101:13341-13345, 2004). Here, we report the generation and analysis of Dasm-1 null mice. We find that genetic ablation of Dasm-1 does not interfere with hippocampal dendrite growth and branching in vitro and in vivo. Moreover, the absence of Dasm-1 does not affect the modulation of dendritic outgrowth induced by brain-derived neurotrophic factor. Importantly, the previously observed impairment in dendrite growth after Dasm-1 knockdown is also observed when the Dasm-1 knockdown is performed in cultured hippocampal neurons from Dasm-1 null mice. These findings indicate that the dendrite arborization phenotype was caused by off-target effects and that Dasm-1 is dispensable for hippocampal dendrite arborization.
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Baudouin, Stéphane J., Julie Angibaud, Gildas Loussouarn та ін. "The Signaling Adaptor Protein CD3ζ Is a Negative Regulator of Dendrite Development in Young Neurons". Molecular Biology of the Cell 19, № 6 (2008): 2444–56. http://dx.doi.org/10.1091/mbc.e07-09-0947.
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A novel idea is emergxsing that a large molecular repertoire is common to the nervous and immune systems, which might reflect the existence of novel neuronal functions for immune molecules in the brain. Here, we show that the transmembrane adaptor signaling protein CD3ζ, first described in the immune system, has a previously uncharacterized role in regulating neuronal development. Biochemical and immunohistochemical analyses of the rat brain and cultured neurons showed that CD3ζ is mainly expressed in neurons. Distribution of CD3ζ in developing cultured hippocampal neurons, as determined by immunofluorescence, indicates that CD3ζ is preferentially associated with the somatodendritic compartment as soon as the dendrites initiate their differentiation. At this stage, CD3ζ was selectively concentrated at dendritic filopodia and growth cones, actin-rich structures involved in neurite growth and patterning. siRNA-mediated knockdown of CD3ζ in cultured neurons or overexpression of a loss-of-function CD3ζ mutant lacking the tyrosine phosphorylation sites in the immunoreceptor tyrosine-based activation motifs (ITAMs) increased dendritic arborization. Conversely, activation of endogenous CD3ζ by a CD3ζ antibody reduced the size of the dendritic arbor. Altogether, our findings reveal a novel role for CD3ζ in the nervous system, suggesting its contribution to dendrite development through ITAM-based mechanisms.
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Allen, Jeffrey B. "Phase-field simulations of isomorphous binary alloys subject to isothermal and directional solidification." Multidiscipline Modeling in Materials and Structures 17, no. 5 (2021): 955–73. http://dx.doi.org/10.1108/mmms-02-2021-0033.
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PurposeIn this work, with a goal to ultimately forward the advancement of additive manufacturing research, the author applies the Wheeler-Boettinger-McFadden model through a progressive series of increasingly complex solidification problems illustrating the evolution of both dendritic as well as columnar growth morphologies. For purposes of convenience, the author assumes idyllic solutions (i.e. the excess energies associated with mixing solid and liquid phases can be neglected).Design/methodology/approachIn this work, the author applied the phase-field model through a progressive series of increasingly complex solidification problems, illustrating the evolution of both dendritic as well as columnar growth morphologies. Beginning with a non-isothermal treatment of pure Ni, the author further examined the isothermal and directional solidification of Cu–Ni binary alloys.Findings(1) Consistent with previous simulation results, solidification simulations from each of the three cases revealed the presence of parabolic, dendrite tips evolving along directions of maximum interface energy. (2) For pure Ni simulations, changes in the anisotropy and noise magnitudes resulted in an increase of secondary dendritic branches and changes in the direction of propagation. The overall shape of the primary structure tended also to elongate with increased anisotropy. (3) For simulations of isothermal solidification of Ni–Cu binary alloys, the development of primary and secondary dendrite arm formation followed similar patterns associated with a pure substance. Calculations of dendrite tip velocity tended to increase monotonically with increasing anisotropy in accordance with previous research. (4) Simulations of directional solidification of Ni–Cu binary alloys with a linear temperature profile demonstrated the presence of cellular dendrites with relatively weak side-branching. The occurrence of solute trapping was also apparent between the primary dendrite columns. Dendrite tip velocities increased with increasing cooling rate.Originality/valueThis research, particularly the section devoted to directional solidification of binary alloys, describes a novel numerical framework and platform for the parametric analysis of various microstructural related quantities, including the effects due to changes in temperature gradient and cooling rate. Both the evolution of the phase and concentration are resolved.
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Bastian, Thomas W., William C. von Hohenberg, Daniel J. Mickelson, Lorene M. Lanier, and Michael K. Georgieff. "Iron Deficiency Impairs Developing Hippocampal Neuron Gene Expression, Energy Metabolism, and Dendrite Complexity." Developmental Neuroscience 38, no. 4 (2016): 264–76. http://dx.doi.org/10.1159/000448514.
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Iron deficiency (ID), with and without anemia, affects an estimated 2 billion people worldwide. ID is particularly deleterious during early-life brain development, leading to long-term neurological impairments including deficits in hippocampus-mediated learning and memory. Neonatal rats with fetal/neonatal ID anemia (IDA) have shorter hippocampal CA1 apical dendrites with disorganized branching. ID-induced dendritic structural abnormalities persist into adulthood despite normalization of the iron status. However, the specific developmental effects of neuronal iron loss on hippocampal neuron dendrite growth and branching are unknown. Embryonic hippocampal neuron cultures were chronically treated with deferoxamine (DFO, an iron chelator) beginning at 3 days in vitro (DIV). Levels of mRNA for Tfr1 and Slc11a2, iron-responsive genes involved in iron uptake, were significantly elevated in DFO-treated cultures at 11DIV and 18DIV, indicating a degree of neuronal ID similar to that seen in rodent ID models. DFO treatment decreased mRNA levels for genes indexing dendritic and synaptic development (i.e. BdnfVI,Camk2a,Vamp1,Psd95,Cfl1, Pfn1,Pfn2, and Gda) and mitochondrial function (i.e. Ucp2,Pink1, and Cox6a1). At 18DIV, DFO reduced key aspects of energy metabolism including basal respiration, maximal respiration, spare respiratory capacity, ATP production, and glycolytic rate, capacity, and reserve. Sholl analysis revealed a significant decrease in distal dendritic complexity in DFO-treated neurons at both 11DIV and 18DIV. At 11DIV, the length of primary dendrites and the number and length of branches in DFO-treated neurons were reduced. By 18DIV, partial recovery of the dendritic branch number in DFO-treated neurons was counteracted by a significant reduction in the number and length of primary dendrites and the length of branches. Our findings suggest that early neuronal iron loss, at least partially driven through altered mitochondrial function and neuronal energy metabolism, is responsible for the effects of fetal/neonatal ID and IDA on hippocampal neuron dendritic and synaptic maturation. Impairments in these neurodevelopmental processes likely underlie the negative impact of early life ID and IDA on hippocampus-mediated learning and memory.
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Thompson-Peer, Katherine L., Laura DeVault, Tun Li, Lily Yeh Jan, and Yuh Nung Jan. "In vivo dendrite regeneration after injury is different from dendrite development." Genes & Development 30, no. 15 (2016): 1776–89. http://dx.doi.org/10.1101/gad.282848.116.
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Zeng, H. C., and L. C. Lim. "Secondary ionic forces in lead molybdate melt solidification." Journal of Materials Research 13, no. 6 (1998): 1426–29. http://dx.doi.org/10.1557/jmr.1998.0203.
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We report a dendritic crystallization of ionic melt of lead molybdate (PbMoO4) under a concentric thermal field. The solidified melt is a PbMoO4 single crystal with [001] axis normal to surface. The dendrite arms propagate and branch along 〈310〉 and 〈130〉, forming a well-organized surface structure. It is evident that the interaction between a cation to its second-nearest anions determines the dendrite development and meltsolidification.
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Gao, Zhi Guo. "Numerical Analysis of Microstructure Development during Laser Welding Nickel-Based Single-Crystal Superalloy Part II: Multicomponent Dendrite Growth." Materials Science Forum 1020 (February 2021): 32–40. http://dx.doi.org/10.4028/www.scientific.net/msf.1020.32.
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A thermal metallurgical coupling model was further developed for multicomponent dendrite growth of primary γ gamma phase during laser welding nickel-based single-crystal superalloys. It is indicated that welding configuration has a predominant role on the overall dendrite trunk spacing than heat input throughout the weld pool, and modifies the dendrite growth kinetics. The dendrite trunk spacing in (001) and [100] welding configuration is finer than that of in (001) and [110] welding configuration. In (001) and [100] welding configuration, the bimodal distribution of dendrite trunk spacing is symmetrical about weld pool centerline, the dendrite trunk spacing in [100] growth region near the weld pool center is coarser than [010], [0ī0] and [001] dendrite growth regions. In (001) and [110] welding configuration, the distribution of dendrite trunk spacing is crystallographically asymmetrical, and the dendrite trunk spacing in [100] growth region is severely coarser than that of [010] and [001] dendrite growth regions. (001) and [110] welding configuration is of particular interest, because dendrite trunk spacing decreases in [100] dendrite growth region and dendrite trunk spacing increases in [010] dendrite growth region from the maximum weld pool width to the end due to crystallography-dependent growth kinetics. Moreover, strict control of low heat input (low laser power and high welding speed) beneficially promotes fine dendrite trunk spacing and reduces the size of dendrite growth regions. High heat input (high laser power and low welding speed) monotonically coarsens dendrite trunk spacing. The dendrite trunk spacing is refined and [100] dendrite growth is suppressed by the optimum low heat input and (001) and [100] welding configuration to improve weldability. An alternative mechanism of solidification cracking because of asymmetrical dendrite trunk growth is proposed. The useful results facilitate understanding of single-crystal superalloys microstructure development and solidification cracking phenomena. The theoretical predictions agree well with the experiment results. Moreover, the model is also applicable to other single-crystal superalloys with similar metallurgical properties by feasible laser welding or laser cladding.
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Gansert, Juliane, Jorge Golowasch, and Farzan Nadim. "Sustained Rhythmic Activity in Gap-Junctionally Coupled Networks of Model Neurons Depends on the Diameter of Coupled Dendrites." Journal of Neurophysiology 98, no. 6 (2007): 3450–60. http://dx.doi.org/10.1152/jn.00648.2007.
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Gap junctions are known to be important for many network functions such as synchronization of activity and the generation of waves and oscillations. Gap junctions have also been proposed to be essential for the generation of early embryonic activity. We have previously shown that the amplitude of electrical signals propagating across gap-junctionally coupled passive cables is maximized at a unique diameter. This suggests that threshold-dependent signals may propagate through gap junctions for a finite range of diameters around this optimal value. Here we examine the diameter dependence of action potential propagation across model networks of dendro-dendritically coupled neurons. The neurons in these models have passive soma and dendrites and an action potential-generating axon. We show that propagation of action potentials across gap junctions occurs only over a finite range of dendritic diameters and that propagation delay depends on this diameter. Additionally, in networks of gap-junctionally coupled neurons, rhythmic activity can emerge when closed loops (re-entrant paths) occur but again only for a finite range of dendrite diameters. The frequency of such rhythmic activity depends on the length of the path and the dendrite diameter. For large networks of randomly coupled neurons, we find that the re-entrant paths that underlie rhythmic activity also depend on dendrite diameter. These results underline the potential importance of dendrite diameter as a determinant of network activity in gap-junctionally coupled networks, such as network rhythms that are observed during early nervous system development.
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Emoto, Kazuo. "Dendrite remodeling in development and disease." Development, Growth & Differentiation 53, no. 3 (2011): 277–86. http://dx.doi.org/10.1111/j.1440-169x.2010.01242.x.
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YE, B., and Y. JAN. "The cadherin superfamily and dendrite development." Trends in Cell Biology 15, no. 2 (2005): 64–67. http://dx.doi.org/10.1016/j.tcb.2004.12.003.
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Whitford, Kristin L., Paul Dijkhuizen, Franck Polleux, and Anirvan Ghosh. "Molecular Control of Cortical Dendrite Development." Annual Review of Neuroscience 25, no. 1 (2002): 127–49. http://dx.doi.org/10.1146/annurev.neuro.25.112701.142932.
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Galenko, P. K., and D. V. Alexandrov. "From atomistic interfaces to dendritic patterns." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, no. 2113 (2018): 20170210. http://dx.doi.org/10.1098/rsta.2017.0210.
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Transport processes around phase interfaces, together with thermodynamic properties and kinetic phenomena, control the formation of dendritic patterns. Using the thermodynamic and kinetic data of phase interfaces obtained on the atomic scale, one can analyse the formation of a single dendrite and the growth of a dendritic ensemble. This is the result of recent progress in theoretical methods and computational algorithms calculated using powerful computer clusters. Great benefits can be attained from the development of micro-, meso- and macro-levels of analysis when investigating the dynamics of interfaces, interpreting experimental data and designing the macrostructure of samples. The review and research articles in this theme issue cover the spectrum of scales (from nano- to macro-length scales) in order to exhibit recently developing trends in the theoretical analysis and computational modelling of dendrite pattern formation. Atomistic modelling, the flow effect on interface dynamics, the transition from diffusion-limited to thermally controlled growth existing at a considerable driving force, two-phase (mushy) layer formation, the growth of eutectic dendrites, the formation of a secondary dendritic network due to coalescence, computational methods, including boundary integral and phase-field methods, and experimental tests for theoretical models—all these themes are highlighted in the present issue. This article is part of the theme issue ‘From atomistic interfaces to dendritic patterns’.
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Li, Haimin, Gang Chen, Bing Zhou, and Shumin Duan. "Actin Filament Assembly by Myristoylated, Alanine-rich C Kinase Substrate–Phosphatidylinositol-4,5-diphosphate Signaling Is Critical for Dendrite Branching." Molecular Biology of the Cell 19, no. 11 (2008): 4804–13. http://dx.doi.org/10.1091/mbc.e08-03-0294.
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Dendrites undergo extensive growth and branching at early stages, but relatively little is known about the molecular mechanisms underlying these processes. Here, we show that increasing the level of myristoylated, alanine-rich C kinase substrate (MARCKS), a prominent substrate of protein kinase C and a phosphatidylinositol-4,5-diphosphate [PI(4,5)P2] sequestration protein highly expressed in the brain, enhanced branching and growth of dendrites both in vitro and in vivo. Conversely, knockdown of endogenous MARCKS by RNA interference reduced dendritic arborization. Results from expression of different mutants indicated that membrane binding is essential for MARCKS-induced dendritic morphogenesis. Furthermore, MARCKS increased the number and length of filamentous actin-based filopodia along neurites, as well as the motility of filopodia, in a PI(4,5)P2-dependent manner. Time-lapse imaging showed that MARCKS increased frequency of filopodia initiation but did not affect filopodia longevity, suggesting that MARCKS may increase dendritic branching through its action on filopodia initiation. These findings demonstrate a critical role for MARCKS–PI(4,5)P2 signaling in regulating dendrite development.
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Huang, Zhen, Keling Zang, and Louis F. Reichardt. "The origin recognition core complex regulates dendrite and spine development in postmitotic neurons." Journal of Cell Biology 170, no. 4 (2005): 527–35. http://dx.doi.org/10.1083/jcb.200505075.
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The origin recognition complex (ORC) ensures exactly one round of genome replication per cell cycle through acting as a molecular switch that precisely controls the assembly, firing, and inactivation of the replication initiation machinery. Recent data indicate that it may also coordinate the processes of mitosis and cytokinesis and ensure the proper distribution of replicated genome to daughter cells. We have found that the ORC core subunits are highly expressed in the nervous system. They are selectively localized to the neuronal somatodendritic compartment and enriched in the membrane fraction. siRNA knockdown of ORC subunits dramatically reduced dendritic branch formation and severely impeded dendritic spine emergence. Expression of ORC ATPase motif mutants enhanced the branching of dendritic arbors. The ORC core complex thus appears to have a novel role in regulating dendrite and dendritic spine development in postmitotic neurons.
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Ilott, Andrew J., Mohaddese Mohammadi, Hee Jung Chang, Clare P. Grey, and Alexej Jerschow. "Real-time 3D imaging of microstructure growth in battery cells using indirect MRI." Proceedings of the National Academy of Sciences 113, no. 39 (2016): 10779–84. http://dx.doi.org/10.1073/pnas.1607903113.
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Lithium metal is a promising anode material for Li-ion batteries due to its high theoretical specific capacity and low potential. The growth of dendrites is a major barrier to the development of high capacity, rechargeable Li batteries with lithium metal anodes, and hence, significant efforts have been undertaken to develop new electrolytes and separator materials that can prevent this process or promote smooth deposits at the anode. Central to these goals, and to the task of understanding the conditions that initiate and propagate dendrite growth, is the development of analytical and nondestructive techniques that can be applied in situ to functioning batteries. MRI has recently been demonstrated to provide noninvasive imaging methodology that can detect and localize microstructure buildup. However, until now, monitoring dendrite growth by MRI has been limited to observing the relatively insensitive metal nucleus directly, thus restricting the temporal and spatial resolution and requiring special hardware and acquisition modes. Here, we present an alternative approach to detect a broad class of metallic dendrite growth via the dendrites’ indirect effects on the surrounding electrolyte, allowing for the application of fast 3D 1H MRI experiments with high resolution. We use these experiments to reconstruct 3D images of growing Li dendrites from MRI, revealing details about the growth rate and fractal behavior. Radiofrequency and static magnetic field calculations are used alongside the images to quantify the amount of the growing structures.
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Lee, Seong-Eun, and Gum Hwa Lee. "Reelin Affects Signaling Pathways of a Group of Inhibitory Neurons and the Development of Inhibitory Synapses in Primary Neurons." International Journal of Molecular Sciences 22, no. 14 (2021): 7510. http://dx.doi.org/10.3390/ijms22147510.
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Reelin is a secretory protein involved in a variety of processes in forebrain development and function, including neuronal migration, dendrite growth, spine formation, and synaptic plasticity. Most of the function of Reelin is focused on excitatory neurons; however, little is known about its effects on inhibitory neurons and inhibitory synapses. In this study, we investigated the phosphatidylinositol 3-kinase/Akt pathway of Reelin in primary cortical and hippocampal neurons. Individual neurons were visualized using immunofluorescence to distinguish inhibitory neurons from excitatory neurons. Reelin-rich protein supplementation significantly induced the phosphorylation of Akt and ribosomal S6 protein in excitatory neurons, but not in most inhibitory neurons. In somatostatin-expressing inhibitory neurons, one of major subtypes of inhibitory neurons, Reelin-rich protein supplementation induced the phosphorylation of S6. Subsequently, we investigated whether or not Reelin-rich protein supplementation affected dendrite development in cultured inhibitory neurons. Reelin-rich protein supplementation did not change the total length of dendrites in inhibitory neurons in vitro. Finally, we examined the development of inhibitory synapses in primary hippocampal neurons and found that Reelin-rich protein supplementation significantly reduced the density of gephyrin–VGAT-positive clusters in the dendritic regions without changing the expression levels of several inhibitory synapse-related proteins. These findings indicate a new role for Reelin in specific groups of inhibitory neurons and the development of inhibitory synapses, which may contribute to the underlying cellular mechanisms of RELN-associated neurological disorders.
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Guo, Zhao, Jianxin Zhou, Yajun Yin, Xu Shen, and Xiaoyuan Ji. "Numerical Simulation of Three-Dimensional Mesoscopic Grain Evolution: Model Development, Validation, and Application to Nickel-Based Superalloys." Metals 9, no. 1 (2019): 57. http://dx.doi.org/10.3390/met9010057.
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The mesoscopic grain model is a multiscale model which takes into account both the dendrite growth mechanism and the vast numerical computation of the actual castings. Due to the pursuit of efficient computation, the mesoscopic grain calculation accuracy is lower than that of dendrite growth model. Improving the accuracy of mesoscopic grain model is a problem to be solved urgently. In this study, referring to the calculation method of solid fraction in microscopic dendrite growth model, a cellular automata model of 3D mesoscopic grain evolution for solid fraction calculated quantitatively at the scale of cell is developed. The developed model and algorithm validation for grain growth simulation is made by comparing the numerical results with the benchmark experimental data and the analytical predictions. The results show that the 3D grain envelopes simulated by the developed model and algorithm are coincident with the shape predicted by the analytical model to a certain extent. Then, the developed model is applied to the numerical simulation of solidification process of nickel-based superalloys, including equiaxed and columnar dendritic grain growth. Our results show good agreement with the related literature.
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Shrestha, B. R., and W. B. Grueber. "Analysis of Dendrite Development in Drosophila Embryos." Cold Spring Harbor Protocols 2011, no. 8 (2011): pdb.prot5658. http://dx.doi.org/10.1101/pdb.prot5658.
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Hill, Sarah E., Manpreet Parmar, Kyle W. Gheres, et al. "Development of dendrite polarity in Drosophila neurons." Neural Development 7, no. 1 (2012): 34. http://dx.doi.org/10.1186/1749-8104-7-34.
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Van Aelst, Linda, and Hollis T. Cline. "Rho GTPases and activity-dependent dendrite development." Current Opinion in Neurobiology 14, no. 3 (2004): 297–304. http://dx.doi.org/10.1016/j.conb.2004.05.012.
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Gao, Zhi Guo. "Numerical Analysis of Microstructure Anomalies during Laser Welding Nickel-Based Single-Crystal Superalloy Part III: Amelioration of Solidification Behavior." Materials Science Forum 1041 (August 4, 2021): 47–56. http://dx.doi.org/10.4028/www.scientific.net/msf.1041.47.
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The contribution of crystallography-dependent metallurgical factors, such as supersaturation of liquid aluminum and minimum dendrite tip undercooling, to solidification behavior and microstructure development is numerically analyzed during Ni-Cr-Al ternary single-crystal superalloy molten pool solidification to better understand thermodynamic and kinetic driving forces behind solidification cracking resistance. The variation of supersaturation of liquid aluminum and minimum dendrite tip undercooling with location of solid/liquid interface is symmetrically consistent in (001)/[100] welding configuration. By comparison, the variation is asymmetrically consistent in (001)/[110] welding configuration. The different distribution is attributed to growth crystallography and dendrite selection. Significant increase of supersaturation of liquid aluminum and dendrite tip undercooling from [010] dendrite growth region to [100] dendrite growth region preferentially aggravates microstructure development as result of nucleation and growth of stray grain formation with the same heat input on each half of the weld pool in (001)/[110] welding configuration. High heat input (both increasing laser power and decreasing welding speed) exacerbates supersaturation of liquid aluminum and dendrite tip undercooling by faster diffusion to incur stray grain formation with severity of contributing thermometallurgical factors for susceptibility to solidification cracking, while low heat input (both decreasing laser power and increasing welding speed) ameliorates microstructure development and increases resistance to solidification cracking. Weld microstructure of optimum welding conditions, such as combination of low heat input and (001)/[100] welding configuration, is less susceptible to solidification cracking to suppress asymmetrical microstructure development and improve weld integrity potential rather than insidious welding conditions, such as combination of high heat input and (001)/[110] welding configuration. Severer supersaturation of liquid aluminum and wider dendrite tip undercooling occur in the [100] dendrite region as consequence of alloying enrichment, while smaller supersaturation of liquid aluminum and narrower dendrite tip undercooling occur in the [001] dendrite region as consequence of alloying depletion to spontaneously facilitate epitaxial growth of single-crystal essential. Symmetrical (001)/[100] welding configuration decreases growth kinetics of dendrite tip with smaller overall supersaturation of liquid aluminum and dendrite tip undercooling than that of asymmetrical (001)/[110] welding configuration regardless of combination of laser power and welding speed. Mitigation of supersaturation of liquid aluminum and dendrite tip undercooling simultaneously alleviate crack-susceptible microstructure development and solidification cracking. Additionally, the appropriate mechanism of solidification cracking resistance improvement through modification of crystallography-dependent supersaturation and undercooling of dendrite tip is proposed. Calculation analyses are sufficiently explained by experiment results in a reasonable way. The additional purpose of this theoretical analysis is to evaluate solidification cracking susceptibility of similar nickel-based or iron-based single-crystal superalloys.
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Ramdan, Raden Dadan, Tomohiro Takaki, Joy Rizki Pangestu Djuansjah, Bondan Tiara Sofyan, and Esah Hamzah. "Development of Phase Field Simulation for the Growth of Dendrite Structure of Al-Si Cast Alloy." Materials Science Forum 737 (January 2013): 37–42. http://dx.doi.org/10.4028/www.scientific.net/msf.737.37.
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Micro to nano scale study of dendrite structure is important in order to have better properties control of casting product. The present study concerns on the morphological study of dendrite structure by phase-field simulation, in order to obtain the morphological growth of this structure that close its real morphology. Focus was given on the morphological growth of dendrite structure of Al-Si cast alloys, therefore thermodynamic data were taken for this type of materials. Anisotropy noise, strength of anisotropy and different undercooled conditions were applied as the variable parameters in the present works. It was observed that by introducing higher anisotropy noise, higher degree fragmentation of dendrite structure was obtained. Similar condition was obtained by introducing higher strength of anisotropy value, that higher degree of fragmentation was obtained. Both of these phenomena was also supported by the heat flux rate features of these variations that higher heat flux rate to almost all direction was obtained with the higher value of anisotropy noise and strength of anisotropy. In addition it was also observed that higher degree fragmentation of dendrite only possible to occur if sufficient undercooled condition established.
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Zyska, Andrzej. "CA Modeling of Microsegregation and Growth of Equiaxed Dendrites in the Binary Al-Mg Alloy." Materials 14, no. 12 (2021): 3393. http://dx.doi.org/10.3390/ma14123393.
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A two-dimensional model based on the Cellular Automaton (CA) technique for simulating free dendritic growth in the binary Al + 5 wt.% alloy was presented. In the model, the local increment of the solid fraction was calculated using a methodology that takes into account changes in the concentration of the liquid and solid phase component in the interface cells during the solidification transition. The procedure of discarding the alloy component to the cells in the immediate vicinity was used to describe the initial, unstable dendrite growth phase under transient diffusion conditions. Numerical simulations of solidification were performed for a single dendrite using cooling rates of 5, 25 and 45 K/s and for many crystals assuming the boundary condition of the third kind (Newton). The formation and growth of primary and secondary branches as well as the development of component microsegregation in the liquid and solid phase during solidification of the investigated alloy were analysed. It was found that with an increase in the cooling rate, the dendrite morphology changes, its cross-section and the distance between the secondary arms decrease, while the degree of component microsegregation and temperature recalescence in the initial stage of solidification increase. In order to determine the potential of the numerical model, the simulation results were compared with the predictions of the Lipton–Glicksman–Kurz (LGK) analytical model and the experimental solidification tests. It was demonstrated that the variability of the dendrite tip diameter and the growth rate determined in the Cellular Automaton (CA) model are similar to the values obtained in the LGK model. As part of the solidification tests carried out using the Derivative Differential Thermal Analysis (DDTA) method, a good fit of the CA model was established in terms of the shape of the solidification curves as well as the location of the characteristic phase transition temperatures and transformation time. Comparative tests of the real structure of the Al + 5 wt.% Mg alloy with the simulated structure were also carried out, and the compliance of the Secondary Dendrite Arm Spacing (SDAS) parameter and magnesium concentration profiles on the cross-section of the secondary dendrites arms was assessed.
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Chen, Yachi, Phyllis Y. Wang, and Anirvan Ghosh. "Regulation of cortical dendrite development by Rap1 signaling." Molecular and Cellular Neuroscience 28, no. 2 (2005): 215–28. http://dx.doi.org/10.1016/j.mcn.2004.08.012.
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Sanes, Dan H., and Parag Chokshi. "Glycinergic transmission influences the development of dendrite shape." NeuroReport 3, no. 4 (1992): 323–26. http://dx.doi.org/10.1097/00001756-199204000-00008.
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Keeler, Austin B., Michael J. Molumby, and Joshua A. Weiner. "Protocadherins branch out: Multiple roles in dendrite development." Cell Adhesion & Migration 9, no. 3 (2015): 214–26. http://dx.doi.org/10.1080/19336918.2014.1000069.
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Corty, M. M., B. J. Matthews, and W. B. Grueber. "Molecules and mechanisms of dendrite development in Drosophila." Development 136, no. 7 (2009): 1049–61. http://dx.doi.org/10.1242/dev.014423.
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He, Chun-Wei, Chien-Po Liao, and Chun-Liang Pan. "Wnt signalling in the development of axon, dendrites and synapses." Open Biology 8, no. 10 (2018): 180116. http://dx.doi.org/10.1098/rsob.180116.
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Wnts are a highly conserved family of secreted glycoproteins that play essential roles in the morphogenesis and body patterning during the development of metazoan species. In recent years, mounting evidence has revealed important functions of Wnt signalling in diverse aspects of neural development, including neuronal polarization, guidance and branching of the axon and dendrites, as well as synapse formation and its structural remodelling. In contrast to Wnt signalling in cell proliferation and differentiation, which mostly acts through β-catenin-dependent pathways, Wnts engage a diverse array of non-transcriptional cascades in neuronal development, such as the planar cell polarity, cytoskeletal or calcium signalling pathways. In this review, we summarize recent advances in the mechanisms of Wnt signalling in the development of axon, dendrite and synapse formation.
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Dailey, M. E., and S. J. Smith. "Dynamics of dendrite development visualized by time-lapse confocal imaging in brain slices." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 806–7. http://dx.doi.org/10.1017/s0424820100140403.
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In the mammalian CNS, dendritic neuronal branches typically are studded with numerous short (<3μm), lateral protrusions called “spines”. Such spines are the primary sites of excitatory synaptic input, and changes in spine morphology are thought to play important roles in plasticity of synaptic function in both the developing and adult animal. However, dynamic changes in spine number and structure are not easily determined by electron microscopy, and the small size of spines has made them difficult to study by conventional light microscopy. Recent advances in vital fluorescent staining and high resolution confocal imaging in tissue slices now afford the possibility of assessing changes in morphology of individual spines on single dendrite branches over time.To investigate the dynamics and plasticity of dendritic structure during development, vital fluorescent staining and time-lapse confocal imaging methods were applied to preparations of live brain slices from developing rat. Tissue slices were prepared from hippocampus of neonatal rat (postnatal day 2-7) and cultured for variable periods of time (hours to weeks).
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Alpár, Alán, Uwe Ueberham, Dávid Lendvai, et al. "Activity‐induced dendrite and dendritic spine development in human amyloid precursor protein transgenic mice." International Journal of Developmental Neuroscience 29, no. 2 (2011): 107–14. http://dx.doi.org/10.1016/j.ijdevneu.2011.01.001.
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Seredyński, Miroslaw, and Jerzy Banaszek. "Front tracking approach to modeling binary alloy solidification." International Journal of Numerical Methods for Heat & Fluid Flow 24, no. 4 (2014): 920–31. http://dx.doi.org/10.1108/hff-02-2013-0069.
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Purpose – The purpose of this paper is to endorse the idea of using a special post-calculating front tracking (FT) procedure, along with the enthalpy-porosity front tracking (EP-FT) single continuum model, in order to identify zones of different dendritic microstructures developing in the mushy zone during cooling and solidification of a binary alloy. Design/methodology/approach – The 2D and 3D algorithms of the FT approach along with different crystal growth laws were implemented in macroscopic calculations of binary alloy solidification with the identification of different dendrite zones developing during the process. Findings – Direct comparison of results predicted by the FT model with that based on the concept of the critical value of the solid volume fraction shows the sensitivity of the latter on an arbitrary assumed value of the dendrite coherency point (DCP). Moreover, for a carefully chosen DCP value the second model provides results that are close to those given by the FT-based approach. It is also observed that the macro-segregation pattern obtained by the proposed method is hardly influenced by chosen dendrite tip kinetics. Originality/value – To the best authors’ knowledge, for the first time the 3D FT model has been used along with the enthalpy porosity approach to simulate the development of zones of different dendrite morphology during binary alloy solidification. And, a weak influence of assumed different dendrite tip kinetics on the macro-segregation pattern has been proved, what justifies this underlying assumption of the EP-FT method.
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Chen, Zhongwei, Yue Hou, Bin Xie, and Qi Zhang. "Dendrite Morphology Evolution of Al6Mn Phase in Suction Casting Al–Mn Alloys." Materials 13, no. 10 (2020): 2388. http://dx.doi.org/10.3390/ma13102388.
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The effects of solute element content and cooling rate on the morphology of Al6Mn phase in suction casting Al–Mn alloys were investigated by transmission electron microscope, scanning electron microscope, and X-ray diffractometer. Results show that Al6Mn dendrite morphology with different degrees of development can occur in the microstructure of as-cast Al–Mn alloys. For the Al–4 wt.% Mn alloy, there are small amounts of block Al6Mn crystals at the center of sample, while we see a block Al6Mn phase and a feathery Al6Mn phase in the sample of Al–6 wt.% Mn alloy. Moreover, the block Al6Mn phases in the Al–8 wt.% Mn alloy disappear, and only snowflake-like Al6Mn phases play a dominant role in the microstructure. However, with an increase in Mn content to 10 wt.%, more dendritic trunks are formed, and secondary dendrite arms are degraded more seriously due to the formation of an icosahedral quasicrystal in suction casting. In addition to the effect of Mn content on Al6Mn morphology, with the increase in cooling rate from the center to the edge of samples, the outline diameter of equiaxed dendrite decreases. The evolution of Al6Mn dendrite morphology and the formation of quasicrystal are further discussed.