Dendritic Structure Research Articles

Modeling hyperbranched polymer formation via ATRP using dissipative particle dynamics

Hyperbranched polymers (HBPs) offer distinguishing, advantageous properties that arise from their distinctive complex topology. One of the effective approaches to the synthesis of hyperbranched structures involves the use of a branching initiator (inibramer) that is activated only after incorporation into a polymer chain. There remain, however, challenges in determining and characterizing the structures of the synthesized HBPs. Dissipative particle dynamics (DPD) was used to probe the effects of inibramer concentration, solvent concentration, and inibramer reactivity on the kinetics, molecular weight, and dispersity of HBPs. Additionally, DPD allows for direct observation of branched structures, which was not possible in previously reported Monte Carlo type simulations. It was found that higher inibramer concentrations led to faster monomer consumption while forming more dendritic structures with fewer defects. Additionally, high dispersities characteristic of HBP systems were found to originate from asymmetric propagation rates between inibramer-inibramer and inibramer-monomer reactions.

Investigations on microstructural, mechanical, and tribological properties of Al-Cu-Ni alloy in cast, heat-treated, and strain-softened conditions

This research investigates the microstructural, mechanical, and tribological properties of Al-Cu-Ni alloys in the as-cast, solutionized, artificially aged condition. In addition, the influence of cold-rolling followed by solutionizing/strain softening on the microstructure and microhardness was evaluated through a comprehensive analysis. Microstructural examination reveals that the addition of nickel to Al-Cu-Ni leads to refined dendritic structures and intermetallic phase formation. Texture analysis and microhardness measurements demonstrate the impact of mechanical and heat treatments on grain size, orientation, and material hardness. Tribological characterization reveals superior wear resistance in the heat treated Al-Cu-Ni alloy, attributed to intermetallic phases and refined microstructures.

Formation mechanism of defects in Invar 36/MnCu functionally graded material fabricated by directed energy deposition

The fabrication of Invar/MnCu functionally graded material (FGM) through directed energy deposition (DED) can satisfy the demands for precision devices in aerospace, providing lightweight properties and integrating thermal stability and vibration damping capabilities. However, basic research on Invar/MnCu FGM is still lacking, hindering its potential applications. To address this gap, this study was conducted using mixed powders and consistent process parameters to print experiments for Invar/MnCu FGM and homogeneous samples. Phases, microstructures, compositions, and thermal expansion properties were thoroughly examined. Three types of defects were detected in the Invar/MnCu FGM sample: unmelted Invar 36 powders, cracks, and pores. The mechanism of unmelted powders was deeply discussed, attributing it to material properties influencing laser absorptivity, the required time for melting powder, and effects on solidus temperature. The mechanism of cracks was also discussed, attributing it to the γ-Fe dendritic structure causing low melting point metal to form an intergranular liquid film, harmful secondary phases mismatched with the terminal alloy, and obvious tensile stresses during the DED process. Additionally, an effective strategy was proposed to reduce defects in Invar/MnCu FGM. After optimization, the specimens exhibited excellent tensile properties, with a yield strength of 262 ± 5 MPa, an ultimate tensile strength of 316 ± 7 MPa, and an elongation of 3 % ± 1 %. This research provides valuable references and insights for subsequent work, offering robust support for better understanding and designing other FGM.

Effect of ultrasonic micro-forging on the microstructure and properties of GH4169 superalloy deposited by laser direct energy deposition

Nickel-based superalloys prepared by laser direct energy deposition (DED) still suffer from microstructure, elemental segregation, and unstable strength, which cannot meet the service requirements and severely limit the application and development of DED-prepared superalloy parts. In this paper, GH4169 specimens with high density and free of defects were prepared by ultrasonic micro-forging assisted laser direct energy deposition (UMT-DED) method. The effects of UMT on the dendritic structure, elemental segregation, and precipitation phases of the alloys prepared by UMT-DED, as well as the densities, hardness, and tensile properties at room and high temperatures were investigated. The contribution of the strengthening mechanism to the yield strength was estimated. The grain refinement mechanism and the deformation mechanism of the Laves phase in GH4169 were discussed. The results show that UMT achieves grain refinement by forming fine crystal strips between the layers. The proportion of fine grain areas increased from 5.9 % to 33.3 %. The plastic deformation introduced by UMT provides external work for dislocation movement to break and fracture part of the Laves phase during plastic deformation, with dislocation cutting of the Laves phase being the main deformation mechanism. The residual stresses was transformed into residual compressive stress. The tensile strength, yield strength, and elongation of the specimens at 25 °C were increased by 4.23 %, 6.42 %, and 23.67 % respectively.

Improvement of Hydrogen-Resistant Gas Turbine Engine Blades: Single-Crystal Superalloy Manufacturing Technology.

This paper presents the results of an analysis of resistance to hydrogen embrittlement and offers solutions and technologies for manufacturing castings of components for critical applications, such as blades for gas turbine engines (GTEs). The values of the technological parameters for directional crystallization (DC) are determined, allowing the production of castings with a regular dendritic structure of the crystallization front in the range of 10 to 12 mm/min and a temperature gradient at the crystallization front in the range of 165-175 °C/cm. The technological process of making GTE blades has been improved by using a scheme for obtaining disposable models of complex profile castings with the use of 3D printing for the manufacture of ceramic molds. The ceramic mold is obtained through an environmentally friendly technology using water-based binders. Short-term tensile testing of the samples in gaseous hydrogen revealed high hydrogen resistance of the CM-88 alloy produced by directed crystallization technology: the relative elongation in hydrogen at a pressure of 30 MPa increased from 2% for the commercial alloy to 8% for the experimental single-crystal alloy.

Optimizing Selective Laser Melting of Inconel 625 Superalloy Through Statistical Analysis of Surface and Volumetric Defects

This article delves into optimizing and modeling the input parameters for the selective laser melting (SLM) process on Inconel 625. The primary aim is to investigate the microstructure within the interlayer regions post-process optimization. For this study, 100 layers with a thickness of 40 µm each were produced. Utilizing the design of experiments (DOE) methodology and employing the Response Surface Method (RSM), the SLM process was optimized. Input parameters such as laser power (LP) and hatch distance (HD) were considered, while changes in microhardness and roughness, Ra, were taken as the responses. Sample microstructure and surface alterations were assessed via scanning electron microscopy (SEM) analysis to ascertain how many defects and properties of Inconel 625 can be controlled using DOE. Porosity and lack of fusion, which were due to rapid post-powder melting solidification, prompted detailed analysis of the flaws both on the surfaces of and in terms of the internal aspects of the samples. An understanding of the formation of these imperfections can help refine the process for enhanced integrity and performance of Inconel 625 printed material. Even slight directional changes in the columnar dendrite structures are discernible within the layers. The microstructural characteristics observed in these samples are directly related to the parameters of the SLM process. In this study, the bulk samples achieved a microhardness of 452 HV, with the minimum surface roughness recorded at 9.9 µm. The objective of this research was to use the Response Surface Method (RSM) to optimize the parameters to result in the minimum surface roughness and maximum microhardness of the samples.

A Learning Dendritic Neuron-Based Motion Direction Detective System and Its Application to Grayscale Images.

In recent research, dendritic neuron-based models have shown promise in effectively learning and recognizing object motion direction within binary images. Leveraging the dendritic neuron structure and On-Off Response mechanism within the primary cortex, this approach has notably reduced learning time and costs compared to traditional neural networks. This paper advances the existing model by integrating bio-inspired components into a learnable dendritic neuron-based artificial visual system (AVS), specifically incorporating mechanisms from horizontal and bipolar cells. This enhancement enables the model to proficiently identify object motion directions in grayscale images, aligning its threshold with human-like perception. The enhanced model demonstrates superior efficiency in motion direction recognition, requiring less data (90% less than other deep models) and less time for training. Experimental findings highlight the model's remarkable robustness, indicating significant potential for real-world applications. The integration of bio-inspired features not only enhances performance but also opens avenues for further exploration in neural network research. Notably, the application of this model to realistic object recognition yields convincing accuracy at nearly 100%, underscoring its practical utility.

Investigation of mechanical properties and high temperature wear resistance of CoFeNi1.5VZr0.4Six high entropy alloys optimized by Si alloying

The current work studies the mechanical properties and high-temperature wear resistance of CoFeNi1.5VZr0.4Six high entropy alloys by Si alloying. The Si alloying transforms Ni7Zr2 into a more wear-resistant silicide phase, and the microstructure changes from lamellar eutectic structure to dendritic structure. The high temperature microhardness, compressive strength and fracture toughness of the HEAs increase first and then decrease with the increasing Si content. The Si alloying in HEAs brings about significant improvements in wear resistance at elevated temperature through the combined effects of phase structure modifications and compositional changes in the tribo-layer. The augmented mechanical properties of the worn subsurface layer contribute to improved wear resistance at elevated temperatures.

Improving the mechanical and wear properties of AZ91 magnesium alloy via laser cladded (AlCu)3.5CoCrNiSnx (x = 0 and 1) high entropy alloy coatings

(AlCu)3.5CoCrNiSnx (x = 0 and 1) high entropy alloy (HEA) coatings were prepared on AZ91 magnesium alloy substrate by laser cladding technology. Both the HEA coatings consisted of FCC phase and BCC phase. The addition of Sn could lead to an increase in the relative proportion of the BCC phase and the formation of coarse dendritic structure in the HEA coating. The average microhardness and average wear weight loss of the (AlCu)3.5CoCrNi coating (612.2 HV and 2.9 mg) and (AlCu)3.5CoCrNiSn coating (562.1 HV and 3.9 mg) were both higher and lower than those of the AZ91 substrate (70.5 HV and 5.5 mg), indicating that the prepared HEA coatings could significantly improve the properties of the substrate. The (AlCu)3.5CoCrNi coating showed better performance than the (AlCu)3.5CoCrNiSn coating due to the grain refinement effect.

Oral nicotinamide provides robust, dose-dependent structural and metabolic neuroprotection of retinal ganglion cells in experimental glaucoma

A compromised capacity to maintain NAD pools is recognized as a key underlying pathophysiological feature of neurodegenerative diseases. NAD acts as a substrate in major cell functions including mitochondrial homeostasis, cell signalling, axonal transport, axon/Wallerian degeneration, and neuronal energy supply. Dendritic degeneration is an early marker of neuronal stress and precedes cell loss. However, little is known about dendritic structural preservation in pathologic environments and remodelling in mature neurons. Retinal ganglion cell dendritic atrophy is an early pathological feature in animal models of the disease and has been demonstrated in port-mortem human glaucoma samples. Here we report that a nicotinamide (a precursor to NAD through the NAD salvage pathway) enriched diet provides robust retinal ganglion cell dendritic protection and preserves dendritic structure in a rat model of experimental glaucoma. Metabolomic analysis of optic nerve samples from the same animals demonstrates that nicotinamide provides robust metabolic neuroprotection in glaucoma. Advances in our understanding of retinal ganglion cell metabolic profiles shed light on the energetic shift that triggers early neuronal changes in neurodegenerative diseases. As nicotinamide can improve visual function short term in existing glaucoma patients, we hypothesize that a portion of this visual recovery may be due to dendritic preservation in stressed, but not yet fully degenerated, retinal ganglion cells.

Oxygen-rich combustion behaviors and mechanisms of a new Ni-Cr-based superalloy fabricated by selective laser melting

The mechanical and combustion behavior of a new Ni-Cr-based superalloy, fabricated by selective laser melting in an atmosphere with an oxygen concentration greater than 99.5 %, was investigated through the analysis of microstructural morphology, elements distribution and combustion kinetics. The results show that heat treatment eliminated the anisotropy of the as-built microstructures and improved the tensile strength. The studied superalloy can be ignited with a combustion threshold of about 2.5 MPa–3 MPa. The burning length and burning rate increase with the increase of pressure. The selective combustion of Al, Ti, Nb, Cr, Fe, Mo, and Cu elements occurred, resulting in the dissolution of γ′, γ", and δ precipitates and formation of holes at the grain boundaries in the heat-affected zone. The microstructures exhibit large elongated grains in the melting zone and column grains in the heat-affected zone along the heat dissipation direction. The combustion products are a mixture of oxides exhibiting dendritic structures in terms of selective combustion, density, and melting point. The findings from this study enhance our comprehension of the combustion process in nickel-based superalloys, offering valuable data and guidance for the advancement of new oxygen-rich combustion-resistant superalloys.

Examinations on small bronze items from the Hallstatt period burial ground at Mitterkirchen in Upper Austria

Abstract A partially destroyed burial ground from the Hallstatt period in the area of Mitterkirchen in Upper Austria was archaeologically investigated. The graves are dated to the Hallstatt C period corresponding to the 8th/7th century BC. Two triangular-headed nails and two lamellar “Buckel” (domed bronze plates) made of Sn-bronze were available for material investigations. One of each was subjected to metallographic examinations. The triangular-headed nail’s bronze contains about 15 wt. %Sn. The dendritic cast structure and the eutectoid phase Cu41Sn11 are clearly visible. What is noticeable is that a Cu41Sn11 layer formed in some areas of the surface. The lamellar Buckel’s microstructure is recrystallized and exhibits only a few deformation twins. Its bronze contains about 13 wt. %Sn. Hence, only very little Cu41Sn11 is present. Elongated Cu2S precipitates indicate that the initial sheet was manufactured by fine forging.

Metastable solidification mechanisms and micromechanical property modulations of rapidly crystallizing Si66.7Ni33.3 peritectic alloy

Metastable solidification mechanisms and micromechanical property modulations of rapidly crystallizing peritectic Si66.7Ni33.3 alloy were systematically investigated by glass fluxing and arc melting techniques. Glass-fluxed samples were undercooled up to 230 K, and the solidification microstructures consisted of Si, NiSi2 and NiSi phases. As the undercooling rose, primary Si phase grew faster along with the enhancement of volume fraction and the morphology transitioned from lamellar structure to dendritic structure. Meanwhile, the thickness of lamellar Si phase basically remained the same, and its length and width decreased gradually. The subsequent peritectic reaction became more intense and peritectic NiSi2 phase became narrower. The 123 K was the critical undercooling for the abrupt rise of eutectic growth velocity, the morphology transition of regular eutectic in the interdendritic gap of NiSi2 to the anomalous eutectic, and the sudden drop of the sample microhardness. The solute Ni content in NiSi2 and NiSi phases increased linearly with a rise in the undercooling, indicating the substantial expansion of solid solubility and the occurrence of an evident solute trapping phenomenon. For arc-melted samples with 8 mm diameter, the solidification microstructure mainly appeared as primary lamellar Si phase surrounded by peritectic NiSi2 phase plus eutectic (NiSi + NiSi2) phase, and the farther away from the sample bottom the smaller the undercooling and the higher the sample microhardness. As the sample diameter decreased to 2 mm, peritectic NiSi2 phase directly nucleated in the sample bottom and the microstructure composition in other regions resembled the large samples. The Si phase possessed lamellar and dendritic structures in the sample top and middle regions, respectively. Moreover, a maximum microhardness was determined in the lower middle region. The research has both scientific and industrial relevance, offering insights that could be applicable to the development and processing of complex alloy systems.

Combined effect of silicon doping and thermal treatment on microstructures and mechanical properties of Ti50Nb20V20Al10 refractory high-entropy alloy

This study investigates the effects of Si doping and thermal treatment on the microstructures and mechanical properties of Ti50Nb20V20Al10 refractory high-entropy alloy (RHEA) with a BCC/B2 dual-phase structure. The as-cast RHEAs exhibit typical dendrite and inter-dendrite structure. Upon Si doping, eutectic M5Si3 phase gradually precipitates along the grain boundaries (GBs), resulting in the increase of yield strength (YS) by over 200 MPa. After recrystallization, all the RHEAs exhibit fully recrystallized microstructures. The eutectic M5Si3 phase disappears while forming nanoscale M5Si3 phase distribute along GBs, thereby enhancing the mechanical properties of the RHEAs. Notably, the recrystallized RHEA with 1 at% Si exhibits favorable specific YS (SYS, 172.9 ± 2.9 MPa·cm3·g−1) and fracture elongation (22.8 ± 6.8 %), respectively. The hindrance effect of nanoscale M5Si3 phase on dislocations motion and the transition from planar slip to cross-slip significantly enhance strain hardening capability and plasticity of the RHEAs. Our research findings are of constructive significance to the study of lightweight energetic structural materials.

VEGFD signaling balances stability and activity-dependent structural plasticity of dendrites

Mature neurons have stable dendritic architecture, which is essential for the nervous system to operate correctly. The ability to undergo structural plasticity, required to support adaptive processes like memory formation, is still present in mature neurons. It is unclear what molecular and cellular processes control this delicate balance between dendritic structural plasticity and stabilization. Failures in the preservation of optimal dendrite structure due to atrophy or maladaptive plasticity result in abnormal connectivity and are associated with various neurological diseases. Vascular endothelial growth factor D (VEGFD) is critical for the maintenance of mature dendritic trees. Here, we describe how VEGFD affects the neuronal cytoskeleton and demonstrate that VEGFD exerts its effects on dendrite stabilization by influencing the actin cortex and reducing microtubule dynamics. Further, we found that during synaptic activity-induced structural plasticity VEGFD is downregulated. Our findings revealed that VEGFD, acting on its cognate receptor VEGFR3, opposes structural changes by negatively regulating dendrite growth in cultured hippocampal neurons and in vivo in the adult mouse hippocampus with consequences on memory formation. A phosphoproteomic screening identified several regulatory proteins of the cytoskeleton modulated by VEGFD. Among the actin cortex-associated proteins, we found that VEGFD induces dephosphorylation of ezrin at tyrosine 478 via activation of the striatal-enriched protein tyrosine phosphatase (STEP). Activity-triggered structural plasticity of dendrites was impaired by expression of a phospho-deficient mutant ezrin in vitro and in vivo. Thus, VEGFD governs the equilibrium between stabilization and plasticity of dendrites by acting as a molecular brake of structural remodeling.

Construction of hard BCC phases FeCrVMnTix wear-resistant high-entropy alloy coatings enhanced by solid solution of Ti elements

To address the complex working conditions encountered by 1Cr13 ferritic/martensitic steel during operation, it is imperative to develop high-entropy alloys (HEAs) protective coatings with enhanced friction resistance. In this work, guided by the valence electron concentration criterion, we constructed a single-phase body-centered cubic (BCC) structure with high hardness. This was achieved through the introduction of titanium (Ti), which has a significantly different atomic radius compared to other elements. FeCrVMnTix (x = 0, 0.5, 1.0, 1.5, and 2.0) coatings were fabricated on 1Cr13 steel surfaces using laser cladding techniques, and the microstructure, mechanical properties, and wear-resistance properties of Ti-doped HEA coatings were investigated. The results reveal that the FeCrVMnTix coatings are comprised of a BCC solid solution. Increasing Ti content refined the dendritic structure of the coatings, enhancing the Vickers hardness from 4.35 GPa to 8.27 GPa and the Young's modulus from 232.6 GPa to 273.2 GPa. Additionally, the wear rate decreased from 3.07 × 10−5 mm3·N−1·m−1 to 4.94 × 10−6 mm3·N−1·m−1. Notably, the FeCrVMnTi2.0 coating demonstrated excellent wear resistance that can be attributed to the solid solution strengthening effect of Ti. These findings underscore the pivotal role of Ti in enhancing the wear resistance of the coatings.

In situ growth and crystallization behavior of PP crystals induced by CF under supercritical N2

High-performance carbon fiber reinforced polypropylene (PP/CF) composite foams were successfully prepared using supercritical N2 as a physical blowing agent, significantly reducing raw material usage. However, the incorporation of supercritical N2 complicates the crystallization behavior of PP/CF, subsequently affects their property. Herein, this study proposes to prepare PP/CF films by solution method and observe in situ growth and crystallization behavior of PP crystals induced by CF under supercritical N2 for the first time. Numerous nucleation sites are formed in CF under supercritical N2, facilitating transcrystalline formation at the interface and confirming CF's potent heterogeneous nucleation capability. The surface tension effect of CF was visualized for the first time, noting the transformation of spherulites into dendritic structures. This transformation, becoming more pronounced with successive isothermal crystallizations, is attributed to changes in the rheological behavior of the PP melt. Furthermore, the research elucidates the mechanism behind CF-induced transcrystalline formation and the periodic growth of the crystal front under supercritical N2. A 20%CF addition reduced grain size by 41.2 % and increased grain density by 2.7 times at 130 °C. However, a higher CF content raises the interfacial free energy required for nucleation, leading to a slower grain growth rate. This work not only addresses the gap in understanding fiber-induced crystallization under supercritical gases but also lays a theoretical foundation for the crystallization behavior of other fibers under similar conditions. It provides critical insights for developing fiber-reinforced composite microcellular plastics with superior properties.

Super‐Resolution Imaging in Collagen‐Abundant Thick Tissues

Expansion microscopy (ExM) has gained increasing popularity for 3D ultrastructural imaging of cultured cells and tissue slices at nanoscale resolution using conventional microscopes via physical expansion of biological tissues. However, its application to collagen‐abundant thick tissues is still challenging. Herein, a new method, collagen ExM (ColExM), optimized for expanding tissues containing more than 70% collagen, is demonstrated. ColExM succeeds in 4.5‐fold linear expansion with minimal structural distortion of corneal and skin tissues. It is compatible with immunostaining, allowing super‐resolution visualization of 3D neural structures innervating hair follicles, corneas, and pancreatic tumors with high stromal collagen content. The method succeeds in identifying individual mitochondria and previously unrecognized dendritic spinelike structures of corneal nerves. It also enables fine mapping of structural rearrangement of tight junctions and actin cytoskeletons. Therefore, ColExM can facilitate the exploration of 3D nanoscale structures in collagen‐rich tissues.

Facile fabrication of Au-Ag alloy nanoparticles/Ag nanowires SERS substrates with bimetallic synergistic effect for ultra-sensitive detection of crystal violet and alkali blue 6B

The bimetallic nanostructure of Au and Ag can integrate two distinct properties into a novel substrate compared to single metal nanostructures. This work presents a rapid and sensitive surface-enhanced Raman scattering (SERS) substrate for detecting illegal food additives and dyes of crystal violet (CV) and alkali blue 6B (AB 6B). Au-Ag alloy nanoparticles/Ag nanowires (Au-Ag ANPs/Ag NWs) were prepared by solid-state ionics method and vacuum thermal evaporation method at 5μA direct current electric field (DCEF), the molar ratio of Au to Ag was 1:18.34. Many 40 nm-140 nm nanoparticles regularly existed on the surface of Ag NWs with the diameters from 80 nm to 150 nm. The fractal dimension of Au-Ag ANPs/Ag NWs is 1.69 due to macroscopic dendritic structures. Compared with single Ag NWs, the prepared Au-Ag ANPs/Ag NWs substrates show superior SERS performance because of higher surface roughness, the SERS active of Ag NWs and bimetallic synergistic effect caused by Au-Ag ANPs, so the limit of detections (LOD) of Au-Ag ANPs/Ag NWs SERS substrates toward detection of CV and AB 6B were as low as 10-16mol/L and 10-9mol/L, respectively. These results indicate that Au-Ag ANPs/Ag NWs substrates can be used for rapid and sensitive detection of CV and AB 6B and have great development potential for detection of illegal food additives and hazardous substances in the fields of environmental monitoring and food safety.

Amyloid-β Causes NMDA Receptor Dysfunction and Dendritic Spine Loss through mGluR1 and AKAP150-Anchored Calcineurin Signaling.

Neuronal excitatory synapses are primarily located on small dendritic protrusions called spines. During synaptic plasticity underlying learning and memory, Ca2+ influx through postsynaptic NMDA-type glutamate receptors (NMDARs) initiates signaling pathways that coordinate changes in dendritic spine structure and synaptic function. During long-term potentiation (LTP), high levels of NMDAR Ca2+ influx promote increases in both synaptic strength and dendritic spine size through activation of Ca2+-dependent protein kinases. In contrast, during long-term depression (LTD), low levels of NMDAR Ca2+ influx promote decreased synaptic strength and spine shrinkage and elimination through activation of the Ca2+-dependent protein phosphatase calcineurin (CaN), which is anchored at synapses via the scaffold protein A-kinase anchoring protein (AKAP)150. In Alzheimer's disease (AD), the pathological agent amyloid-β (Aβ) may impair learning and memory through biasing NMDAR Ca2+ signaling pathways toward LTD and spine elimination. By employing AKAP150 knock-in mice of both sexes with a mutation that disrupts CaN anchoring to AKAP150, we revealed that local, postsynaptic AKAP-CaN-LTD signaling was required for Aβ-mediated impairment of NMDAR synaptic Ca2+ influx, inhibition of LTP, and dendritic spine loss. Additionally, we found that Aβ acutely engages AKAP-CaN signaling through activation of G-protein-coupled metabotropic glutamate receptor 1 (mGluR1) leading to dephosphorylation of NMDAR GluN2B subunits, which decreases Ca2+ influx to favor LTD over LTP, and cofilin, which promotes F-actin severing to destabilize dendritic spines. These findings reveal a novel interplay between NMDAR and mGluR1 signaling that converges on AKAP-anchored CaN to coordinate dephosphorylation of postsynaptic substrates linked to multiple aspects of Aβ-mediated synaptic dysfunction.