laminar structure
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2021 ◽  
Author(s):  
Jordan DeKraker ◽  
Roy AM Haast ◽  
Mohamed D Yousif ◽  
Bradley Karat ◽  
Stefan Köhler ◽  
...  

AbstractThe archicortical hippocampus differs, like the neocortex, in its folding patterns between individuals. Here, we present an automated and robust BIDS-App, HippUnfold, for defining and indexing subject-specific hippocampal folding in MRI, analogous to popular tools used in neocortical reconstruction. This is critical for inter-individual alignment, with topology as the basis for homology. This topological framework enables qualitatively new analyses of morphological and laminar structure in the hippocampus or hippocampal subfields, and is critical for the advancement of neuroimaging analyses at a meso- or micro-scale. HippUnfold uses state-of-the-art deep learning combined with previously developed topological constraints on hippocampal tissue. It is designed to work with commonly employed sub-millimetric MRI acquisitions, with extensibility to microscopic resolutions as well. In this paper we illustrate the power of HippUnfold in feature extraction, and its construct validity compared to several extant hippocampal subfield analysis methods.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Paul Linton

Abstract We typically distinguish between V1 as an egocentric perceptual map and the hippocampus as an allocentric cognitive map. In this article, we argue that V1 also functions as a post-perceptual egocentric cognitive map. We argue that three well-documented functions of V1, namely (i) the estimation of distance, (ii) the estimation of size, and (iii) multisensory integration, are better understood as post-perceptual cognitive inferences. This argument has two important implications. First, we argue that V1 must function as the neural correlates of the visual perception/cognition distinction and suggest how this can be accommodated by V1’s laminar structure. Second, we use this insight to propose a low-level account of visual consciousness in contrast to mid-level accounts (recurrent processing theory; integrated information theory) and higher-level accounts (higher-order thought; global workspace theory). Detection thresholds have been traditionally used to rule out such an approach, but we explain why it is a mistake to equate visibility (and therefore the presence/absence of visual experience) with detection thresholds.


2021 ◽  
Author(s):  
A. Ferrández-Roldán ◽  
M. Fabregà-Torrus ◽  
G. Sánchez-Serna ◽  
E. Durán-Bello ◽  
M. Joaquín-Lluís ◽  
...  

AbstractA key problem in understanding chordate evolution has been the origin of sessility of ascidians, and whether the appendicularian free-living style represents a primitive or derived condition of tunicates. To address this problem, we performed comprehensive developmental and genomic comparative analyses of the cardiopharyngeal gene regulatory network (GRN) between appendicularians and ascidians. Our results reveal that the cardiopharyngeal GRN has suffered a process of evolutionary deconstruction with massive ancestral losses of genes (Mesp, Ets1/2, Gata4/5/6, Mek1/2, Tbx1/10, and RA- and FGF-signaling related genes) and subfunctions (e.g. FoxF, Islet, Ebf, Mrf, Dach and Bmp signaling). These losses have led to the deconstruction of two modules of the cardiopharyngeal GRN that in ascidians are related to early and late multipotent state cells involved in lineage fate determination towards first and secondary heart fields, and siphon muscle. Our results allow us to propose an evolutionary scenario, in which the evolutionary deconstruction of the cardiopharyngeal GRN has had an adaptive impact on the acceleration of the developmental cardiac program, the redesign of the cardiac architecture into an open-wide laminar structure, and the loss of pharyngeal muscle. Our findings, therefore, provide evidence supporting that the ancestral tunicate had a sessile ascidian-like lifestyle, and points to the deconstruction of the cardiopharyngeal GRN in appendicularians as a key event that facilitated the evolution of their pelagic free-living style connected to the innovation of the house.


Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3025 ◽  
Author(s):  
Marcin Barszcz ◽  
Mykhaylo Pashechko ◽  
Krzysztof Dziedzic ◽  
Jerzy Jozwik

This paper investigates the friction process between an Fe-based coating and C45 steel with surface-active lubrication, as well as examines the coating surface before and after tribological testing. As a result, it is possible to determine whether the surface undergoes self-organization during friction. Coatings were produced by hardfacing a subeutectic alloy Fe-Mn-C-B modified by silicon, nickel, chromium and copper. Tribological tests were performed using a pin-on-disc tribometer. The pin (coating) and the disc made of steel C45 were subjected to heat treatment (hardening and tempering). The tests were carried out under loads of 3 MPa, 7 MPa and 10 MPa at a constant sliding velocity of 0.4 m/s and a sliding distance of 5700 m using a surface-active lubricant (glycerine oil). Obtained results were compared with the published results of previous tests carried out under the same conditions but under a load of 20 MPa. Obtained microscopic and spectroscopic results demonstrate that that the friction pair materials (the coating made of subeutectic alloy Fe-Mn-C-B modified by Si, Ni, Cr, Cu and C45 steel) and the surface-active lubricant cause self-organization during friction. The friction surface of the coatings has a flay-laminar structure and is covered with triboreaction products. The surface shows the presence of wear-resistant compounds such as oxides, carbides, borides and nitrides.


2020 ◽  
Vol 27 (3) ◽  
pp. 149-155
Author(s):  
Shan-Shan Wang ◽  
Yu-Yan Lu ◽  
Chen-Hao Yao ◽  
Shuo Qi ◽  
Jian-Xin Cheng ◽  
...  

Elaphe schrenckii (Serpentes, Colubridae), a kind of large nonvenomous snakes and great significance to maintain the stability of ecosystem in China. We provide detailed descriptions of the sperm microstructure and ultrastructure of E. schrenckii, experimented by light microscope and transmission electron microscope. The spermatozoon of E. schrenckii is filiform and consists of head and tail regions. The cross-section of acrosomal vesicle is always rounded and divided into medulla inside and cortex outside. The ultrastructure of acrosome complex observed the unilateral ridge, the single perforatorium, the perforatorium base plate, the epinuclear lucent zone, the subacrosomal space and the nuclear fossa at the end of nucleus connect the neck region. The neck region is short with the stratified laminar structure and observed the distal centriole and the proximal centriole are perpendicular and both consisted of nine triplets. Midpiece is long and observed the extracellular microtubules, the multilaminar membranec, the mitochondria with the dense bodies discontinuity distribting, the fibrous sheath, and the axoneme. The principal piece is after the annulus with no mitochondrias and the end piece with no mitochondrias neither the fibrous sheath. Our study contrasted the spermatozoa ultrastructure of 8 species belong to 5 families and 6 genera and added the sperm measurement compare, summarized that three Colubridae snakes are more similar than others momentarily but some specific characteristics in E. schrenckii and proved that the ultrastructure of sperm related to phylogeny in some ways.


2020 ◽  
Vol 836 ◽  
pp. 90-96 ◽  
Author(s):  
Viktor V. Gabov ◽  
Denis A. Zadkov ◽  
Andrey Yu. Kuzkin ◽  
Aleksandr S. Elikhin

The paper analyzes the structure of coal beds. It is noted that coal beds belong to laminar massifs with characteristic oriented structure and pronounced anisotropy of strength properties, and include rock layers and consolidated hard inclusions. The quality criteria of the coal loosening process are highlighted. A selective method of separating coal from a massif by cutting along weakened surfaces is proposed as an alternative to the existing combine technology with continuous cutting of a massif from the surface.


2020 ◽  
Vol 44 (38) ◽  
pp. 16370-16383
Author(s):  
Pei Wu ◽  
Xiaona Zhao ◽  
Chunhe Li ◽  
Minchen Yang ◽  
Guojun Li ◽  
...  

TiO2-based nanosheets (TNS) modified with Fe2O3 and Y2O3 particles (Fe2O3/Y2O3@TNS), possessing a laminar structure with large specific surface area of 382 m2 g−1, were synthesized via a one-pot hydrothermal method.


2019 ◽  
Author(s):  
Jun Zhuang ◽  
Rylan S Larsen ◽  
Kevin T Takasaki ◽  
Naveen D Ouellette ◽  
Tanya L Daigle ◽  
...  

Location-sensitive and motion-sensitive units are the two major functional types of feedforward projections from lateral genicular nucleus (LGN) to primary visual cortex (V1) in mouse. The distribution of these inputs in cortical depth remains under debate. By measuring the calcium activities of LGN axons in V1 of awake mice, we systematically mapped their functional and structural properties. Although both types distributed evenly across cortical depth, we found that they differ significantly across multiple modalities. Compared to the location-sensitive axons, which possessed confined spatial receptive fields, the motion-sensitive axons lacked spatial receptive fields, preferred lower temporal, higher spatial frequencies and had wider horizontal bouton spread. Furthermore, the motion-sensitive axons showed a strong depth-dependent motion direction bias while the location-sensitive axons showed a depth-independent OFF dominance. Overall, our results suggest a new model of receptive biases and laminar structure of thalamic inputs to V1.


Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 13 ◽  
Author(s):  
Bin Zhang ◽  
Jaehyun Lee ◽  
Mincheol Kim ◽  
Naeeung Lee ◽  
Hyungdong Lee ◽  
...  

The macroscopic assembly of two-dimensional materials into a laminar structure has received considerable attention because it improves both the mechanical and chemical properties of the original materials. However, conventional manufacturing methods have certain limitations in that they require a high temperature process, use toxic solvents, and are considerably time consuming. Here, we present a new system for the self-assembly of layer-by-layer (LBL) graphene oxide (GO) via an electrohydrodynamic (EHD) jet printing technique. During printing, the orientation of GO flakes can be controlled by the velocity distribution of liquid jet and electric field-induced alignment spontaneously. Closely-packed GO patterns with an ordered laminar structure can be rapidly realized using an interfacial assembly process on the substrates. The surface roughness and electrical conductivity of the LBL structure were significantly improved compared with conventional dispensing methods. We further applied this technique to fabricate a reduced graphene oxide (r-GO)-based supercapacitor and a three-dimensional (3D) metallic grid hybrid ammonia sensor. We present the EHD-assisted assembly of laminar r-GO structures as a new platform for preparing high-performance energy storage devices and sensors.


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