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Granule cells (GCs) are the most numerous cell type in the cerebellum and indeed, in the brain: at least 99% of all cerebellar neurons are granule cells. In this review article, we first consider the formation of the upper rhombic lip, from which all granule cell precursors arise, and the way by which the upper rhombic lip generates the external granular layer, a secondary germinal epithelium that serves to amplify the upper rhombic lip precursors. Next, we review the mechanisms by which postmitotic granule cells are generated in the external granular layer and migrate radially to settle in the granular layer. In addition, we review the evidence that far from being a homogeneous population, granule cells come in multiple phenotypes with distinct topographical distributions and consider ways in which the heterogeneity of granule cells might arise during development.

We measured the densities (fmol/mg protein) of 15 different receptors of various transmitter systems in the supragranular, granular and infragranular strata of 44 areas of visual, somatosensory, auditory and multimodal association systems of the human cerebral cortex. Receptor densities were obtained after labeling of the receptors using quantitative receptor autoradiography in human postmortem brains. The mean density of each receptor type over all cortical layers and of each of the three major strata varies between cortical regions. In a cortical area, the multi-receptor fingerprints of its strata (i.e., polar plots, each visualizing the densities of multiple receptor types in supragranular, granular or infragranular layers of the cortical area) differ in shape and size indicating regional and laminar specific balances between the receptors. Furthermore, the three strata are clearly segregated into well definable clusters by their receptor fingerprints. Fingerprints of cortical areas systematically vary between functional networks, and with the hierarchical levels within sensory systems. Primary sensory areas are clearly separated from all other cortical areas particularly by their very high muscarinic M and nicotinic α β receptor densities, and to a lesser degree also by noradrenergic α and serotonergic 5-HT receptors. Early visual areas of the dorsal and ventral streams are segregated by their multi-receptor fingerprints. The results are discussed on the background of functional segregation, cortical hierarchies, microstructural types, and the horizontal (layers) and vertical (columns) organization in the cerebral cortex. We conclude that a cortical column is composed of segments, which can be assigned to the cortical strata. The segments differ by their patterns of multi-receptor balances, indicating different layer-specific signal processing mechanisms. Additionally, of the 44 areas reflect the segregation of the cerebral cortex into functionally and topographically definable groups of cortical areas (visual, auditory, somatosensory, limbic, motor), and reveals their hierarchical position (primary and unimodal (early) sensory to higher sensory and finally to multimodal association areas). Densities of transmitter receptors vary between areas of human cerebral cortex.Multi-receptor fingerprints segregate cortical layers.The densities of all examined receptor types together reach highest values in the supragranular stratum of all areas.The lowest values are found in the infragranular stratum.Multi-receptor fingerprints of entire areas and their layers segregate functional systemsCortical types (primary sensory, motor, multimodal association) differ in their receptor fingerprints.

Rockfalls can pose a significant threat to traffic safety in mountainous areas. Galleries covered by a granular layer have proven effective in protecting both the people and the infrastructure from falling rock blocks. However, quantifying the impact for structural design purposes remains challenging as this force is strongly influenced by the shape of the blocks, among other factors. Here, we propose a semi-empirical model to evaluate the maximum value of the impact force exerted by an irregularly-shaped rock block on a granular layer. The model introduces a work-energy ratio ( α ), which is a dimensionless parameter that depends on properties of both the block and the granular layer. We evaluate a significant dependence of α on the block shape ( N *) as well as on the thickness ( T s ) and strength-like indentation resistance ( f* ) of the granular layer. We show that α is lower for blocks with sharp noses (low N* ) and for layers with low f *. Furthermore, we identify a threshold value of T s , above which α becomes independent of T s . We validate our model on large-scale experiments as well as on a variety of published data and compare the model’s performance with that of existing models. The model exhibits superior performance in realistic rockfall scenarios, suggesting a good potential for implementation in gallery design.

Plant lipid transfer proteins (LTPs) are distinguished by their capacity to facilitate lipid transport in vitro between membranes. This includes the transportation of lipid constituents from the tapetum to the microspore, thereby playing a pivotal role in the synthesis and construction of the pollen wall, encompassing the formation of the pollen aperture. However, our understanding of LTPs and their role in pollen aperture formation in rice remains limited. In this study, we have isolated and characterized a male sterile rice mutant named as pollen aperture defect 1 ( Ospad1 ). When compared to the wild type, Ospad1 mutant plants exhibit pollen grain abortion due to the absence of the fibrillar-granular layer, ultimately leading to the leakage of contents from the malformed aperture. OsPAD1 encodes a non-specific LTP and is specifically expressed in the microspore during male development. Subsequently, in vitro lipid binding assays reveal that the recombinant OsPAD1 protein has the capability to bind to a broad spectrum of lipids. The malfunction of OsPAD1 results in disrupted lipid metabolism and compromised pollen aperture, ultimately leading to male sterility. Furthermore, yeast two-hybrid, bimolecular fluorescent complementation and pull-down assays all demonstrate that OsPAD1 can directly interact with OsINP1, an orthologue of a crucial aperture factor in Arabidopsis, together regulating rice aperture development. These findings offer new insights into the molecular mechanisms that underlie the function of LTPs in rice pollen aperture formation. This research holds potential implications not only for rice but also for other cereal crops. Key message We propose that OsPAD1 associates with lipids in the tapetum and unevenly deposits on the pollen surface, forming the fibrillar-granular layer and endexine under the recruitment of OsINP1.

Frictional properties of sliding surfaces have practical importance in a variety of applications. Therefore, the present study investigates the ageing or holding time-dependent static friction of a wet granular layer using a slide-free-slide (SFS) friction test. It is observed that the static friction varies as a logarithm of hold time. Further, the Mohr–Coulombs’ law of friction is used to determine adhesive friction and normal stress-dependent friction. The scaling law analysis has shown that the exponent of adhesive friction is more prominent in magnitude than the corresponding coefficient of friction. A static friction model, based on the formation and rupture of capillary bridges, has also been proposed for predicting the peaks of static friction at different hold times. At the end, the power laws, which correlate the number of attached capillary bridges and adhesion constant with hold time, are proposed to justify the present results. Graphical Abstract

We consider the problem on the flow of an ideal fluid along a flat surface with a fixed granular layer lying on it. The layer has the form of a semi-infinite step of finite thickness and consists of an infinite number of statistically uniformly distributed identical spherical granules. The problem is solved using a previously developed method of self-consistent field, which allows one to study the effects of hydrodynamic interaction of a large number of spherical particles in ideal-fluid flows, including in the presence of external boundaries, and to obtain averaged dynamic characteristics of such flows. An analytical function describing the averaged fluid velocity field both inside and outside the layer is obtained in the first approximation with respect to the volume fraction of the granules in the layer.

We present a theory of the inner layer of the cerebellar cortex, the granular layer, where the main excitatory input to the cerebellum is received. We ask how input signals are converted into an internal code and what form that has. While there is a computational element, and the ideas are quantified with a computer simulation, the approach is primarily evidence-led and aimed at experimenters rather than the computational community. Network models are often simplified to provide a noiseless medium for sophisticated computations. We propose, with evidence, the reverse: physiology is highly adapted to provide a noiseless medium for straightforward computations. We find that input data are converted to a hyper low-resolution internal code. Information is coded in the joint activity of large cell groups and therefore has minimum spatial dimensions—the dimensions of a code group. The conversion exploits statistical effects of random sampling. Code group dimensions are an effect of topography, cell morphologies and granular layer architecture. The activity of a code group is the smallest unit of information but not the smallest unit of code—the same information is coded in any random sample of signals. Code in this form is unexpectedly wasteful—there is a huge sacrifice of resolution—but may be a solution to fundamental problems involved in the biological representation of information.

Present paper deals with the development of a Mechanistic-Empirical model of the strain-based design of perpetual road pavement using Odemark's principle. The bituminous pavement which can withstand minimum design traffic of 300 msa has been classified as perpetual pavement in this paper. The pavement has been considered as a three-layered system with a top layer of bituminous mix followed by unbound granular materials which rest on soil subgrade. The constituent bituminous layer thickness in the pavement has been determined by limiting the radial tensile strain at the bottom of the bituminous layer against fatigue and the vertical compressive strain at the top of the subgrade against rutting. The allowable strain against rutting and fatigue has been used in the present analysis from mechanistic-empirical correlations recommended in IRC:37-2018. The pavement section has been transformed into a homogeneous system by Odemark's method for application of Boussinesq's theory. To validate the thickness of the perpetual pavement, the strain at different layer interfaces in the pavement was compared using IITPAVE software, which shows the pavement section using present method is safe against rutting but marginally fails under fatigue. Moreover, conventional pavement thickness obtained using IRC:37-2018 were compared with the present method, which shows reasonably good convergence. It has been found that the bituminous layer thickness in a layered system of pavement seems to be more sensitive to fatigue than rutting. In this backdrop, modified fatigue and rutting strain values have been recommended for the design of perpetual road pavement.

Previous studies on the granular layer of the cerebellar cortex have revealed a wide distribution of different subpopulations of less-known large neuron types, called “non-traditional large neurons”, which are distributed in three different zones of the granular layer. These neuron types are mainly involved in the formation of intrinsiccircuits inside the cerebellar cortex. A subpopulation of these neuron types is represented by the synarmotic neuron, which could play a projective role within the cerebellar circuitry. The synarmotic neuron cell body map within the internal zone of the granular layer or in the subjacent white substance. Furthermore, the axon crosses the granular layer and runs in the subcortical white substance, to reenter in an adjacent granular layer, associating two cortico-cerebellar regions of the same folium or of different folia, or could project to the intrinsic cerebellar nuclei. Therefore, along with the Purkinje neuron, the traditional projective neuron type of the cerebellar cortex, the synarmotic neuron is candidate to represent the second projective neuron type of the cerebellar cortex. Studies of chemical neuroanatomy evidenced a predominant inhibitory GABAergic nature of the synarmotic neuron, suggesting that it may mediate an inhibitory GABAergic output of cerebellar cortex within cortico-cortical interconnections or in projections towards intrinsic cerebellar nuclei. On this basis, the present minireview mainly focuses on the morphofunctional and neurochemical data of the synarmotic neuron, and explores its potential involvement in some forms of cerebellar ataxias.

This study presents numerical simulations of railway track with unreinforced and geocell-reinforced substructure. A software based on the Finite Element Method (FEM) and on the Finite Layer Method (FLM) was used to simulate a hypothetical reinforced railway track based on an unreinforced field test with an instrumented railway track previously studied. A parametric analysis with different railway granular layer thicknesses and subgrade resilient moduli was implemented for both reinforced and unreinforced situations. The analyses were focused on vertical stresses on the top of the subgrade and vertical displacements of the rails and sleepers. The objective was to evaluate the geocell reinforcement efficiency in improving railway track performance and to provide a more comprehensive overview of the benefits from the reinforcement insertion in the railway substructure according to its characteristics. The results indicated that the geocell-reinforced infrastructure demonstrated reductions of up to 13% in vertical stresses on the top of the subgrade and 12% and 19% in vertical displacements of the rails and sleepers, respectively. Geocell-reinforcement presented better performance in thinner granular layers and in less stiff subgrades.