Die Nerven und das Bindegewebe der Pia des Menschen im mikrophotographischen Bild

Die Nerven der Pia des Menschen können mit der Silberkarbonattechnik von del Rio Hortega an Ganzpräparaten mikrophotographisch klar wiedergegeben und zwanglos in 2 Systeme eingeteilt werden: 1. Das perivaskuläre System, das von Nerven gebildet wird, die nach ihrem Eintritt in die Pia direkt zu den Gefäßen verlaufen und die letzteren mit einem dichten Geflecht umgeben. Das Grundnetz, welches von Nerven gebildet wird, die a) gleich nach ihrem Eintritt in die Pia sich aufsplittern und den Hauptteil des Grundnetzes bilden; b) von Nerven, welche von einem gefäßwärts verlaufenden Nerven sich abzweigen; c) von Nerven, welche zum perivaskulären Plexus gehören, und schließlich d) von starken Nervenbündeln, welche innerhalb des Grundnetzes zahlreiche Plexus bilden und allmählich in dasselbe übergehen. Das Grundnetz selbst erscheint histologisch als ein in sich geschlossenes Ganzes und enthält keine besonderen Endformationen. Die Strukturen des Bindegewebes zerfallen ebenfalls in 2 Systeme: A. das perivaskuläre Gewebe und B. das die Maschen der Gefäße ausfüllende Netz. A. Die oberflächliche Schicht der Adventitia besteht aus dichten, gleichmäßig starken, parallel verlaufenden Fasern. Die 2. Lage enthält große, ovale oder birnenförmige Zellen mit zahlreichen Ausläufern, welche in der Literatur vielfach als Ganglienzellen gedeutet worden sind. Die 3. Schicht ist durch ovale Auftreibungen ihrer Fasern charakterisiert und die 4. besteht aus zarten, der Media anliegenden Fibrillen. B. Die Maschen zwischen den Gefäßen sind von einem dichten Gewirr sich sternförmig kreuzender Fasern ausgefüllt. Es bestehen direkte Verbindungen zwischen dem Bindegewebe und den Zellen der Arachnoidea. The nerves and connective tissue of the human pia were investigated with the silver carbonate method of del Rio Hortega . The nerves of the pia form two distinctly different but closely associated systems: 1. the perivascular system is made up of nerves which enter the pia, give numerous branches to the ground network (Grundnetz) (Fig. 1), and form perivascular plexuses (Figs. 2, 3, 4) and, 2. the ground network (Grundnetz), which spreads out over the entire pia and is supported by connective tissue structures. The ground network is formed by: A) nerves which enter the pia and split into numerous branches (Fig. 5), B) ramification of perivascular nerves (Figs. 6, 7, 8, 9), C) numerous plexuses derived from coarse nerves which have no direct connection with the vessels; these plexuses gradually merge with the ground network (Figs. 10, 11, 12). The ground network is a dense interwoven structure without demonstrable terminal formations (Fig. 13). The latter have been found only on the media of vessels (Fig. 14). The connective tissue structures are no less complicated than those of the nerves and can also be subdivided into two systems: 1. the adventitia, and 2. the interwoven network of stellate fibers which fills in the space between the vessels. In the adventitia there can be distinguished four layers: A) the upper which contains coarse parallel fibers (Fig. 15), B) the second which is characterized by large, oval or round elements with numerous processes (Fig. 16), C) the third which is composed of fibers with numerous bead-like swellings along their course (Figs. 17, 18), and D) the fourth which consists of delicate fibers which lie directly on the media (Fig. 19). The meshes between the vessels are filled with stellate fiber formations (Fig. 20). The connective tissue fibers of the upper strata of the pia are connected with the processes of the cells of the arachnoidea and are surrounded by numerous connective tissue loops (Fig. 21). Les nerfs et le tissue conjonctif de la pie-mère humaine furent vérifiés à l'aide de la microphotographie de pièces du tissue entier imprégnées à la méthode de del Rio Hortega . Les nerfs montrent deux systèmes différents: 1. Le système périvasculaire formé par des nerfs qui en entrant dans la piemère joignent les vaisseaux en entournant ceux-ci avec un réseau dense.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41654/1/702_2005_Article_BF01227770.pd

Three-dimensional magnetic flux-closure patterns in mesoscopic Fe islands

We have investigated three-dimensional magnetization structures in numerous mesoscopic Fe/Mo(110) islands by means of x-ray magnetic circular dichroism combined with photoemission electron microscopy (XMCD-PEEM). The particles are epitaxial islands with an elongated hexagonal shape with length of up to 2.5 micrometer and thickness of up to 250 nm. The XMCD-PEEM studies reveal asymmetric magnetization distributions at the surface of these particles. Micromagnetic simulations are in excellent agreement with the observed magnetic structures and provide information on the internal structure of the magnetization which is not accessible in the experiment. It is shown that the magnetization is influenced mostly by the particle size and thickness rather than by the details of its shape. Hence, these hexagonal samples can be regarded as model systems for the study of the magnetization in thick, mesoscopic ferromagnets.Comment: 12 pages, 11 figure

Megafaunal Community Structure of Andaman Seamounts Including the Back-Arc Basin – A Quantitative Exploration from the Indian Ocean

Species rich benthic communities have been reported from some seamounts, predominantly from the Atlantic and Pacific Oceans, but the fauna and habitats on Indian Ocean seamounts are still poorly known. This study focuses on two seamounts, a submarine volcano (cratered seamount – CSM) and a non-volcano (SM2) in the Andaman Back–arc Basin (ABB), and the basin itself. The main purpose was to explore and generate regional biodiversity data from summit and flank (upper slope) of the Andaman seamounts for comparison with other seamounts worldwide. We also investigated how substratum types affect the megafaunal community structure along the ABB. Underwater video recordings from TeleVision guided Gripper (TVG) lowerings were used to describe the benthic community structure along the ABB and both seamounts. We found 13 varieties of substratum in the study area. The CSM has hard substratum, such as boulders and cobbles, whereas the SM2 was dominated by cobbles and fine sediment. The highest abundance of megabenthic communities was recorded on the flank of the CSM. Species richness and diversity were higher at the flank of the CSM than other are of ABB. Non-metric multi-dimensional scaling (nMDS) analysis of substratum types showed 50% similarity between the flanks of both seamounts, because both sites have a component of cobbles mixed with fine sediments in their substratum. Further, nMDS of faunal abundance revealed two groups, each restricted to one of the seamounts, suggesting faunal distinctness between them. The sessile fauna corals and poriferans showed a significant positive relation with cobbles and fine sediments substratum, while the mobile categories echinoderms and arthropods showed a significant positive relation with fine sediments only

Discontinuous properties of current-induced magnetic domain wall depinning

The current-induced motion of magnetic domain walls (DWs) confined to nanostructures is of great interest for fundamental studies as well as for technological applications in spintronic devices. Here, we present magnetic images showing the depinning properties of pulse-current-driven domain walls in well-shaped Permalloy nanowires obtained using photoemission electron microscopy combined with X-ray magnetic circular dichroism. In the vicinity of the threshold current density (J th = 4.2 × 10 11 â.A.m-2) for the DW motion, discontinuous DW depinning and motion have been observed as a sequence of "Barkhausen jumps". A one-dimensional analytical model with a piecewise parabolic pinning potential has been introduced to reproduce the DW hopping between two nearest neighbour sites, which reveals the dynamical nature of the current-driven DW motion in the depinning regime

Stress granules, RNA-binding proteins and polyglutamine diseases: too much aggregation?

Stress granules (SGs) are membraneless cell compartments formed in response to different stress stimuli, wherein translation factors, mRNAs, RNA-binding proteins (RBPs) and other proteins coalesce together. SGs assembly is crucial for cell survival, since SGs are implicated in the regulation of translation, mRNA storage and stabilization and cell signalling, during stress. One defining feature of SGs is their dynamism, as they are quickly assembled upon stress and then rapidly dispersed after the stress source is no longer present. Recently, SGs dynamics, their components and their functions have begun to be studied in the context of human diseases. Interestingly, the regulated protein self-assembly that mediates SG formation contrasts with the pathological protein aggregation that is a feature of several neurodegenerative diseases. In particular, aberrant protein coalescence is a key feature of polyglutamine (PolyQ) diseases, a group of nine disorders that are caused by an abnormal expansion of PolyQ tract-bearing proteins, which increases the propensity of those proteins to aggregate. Available data concerning the abnormal properties of the mutant PolyQ disease-causing proteins and their involvement in stress response dysregulation strongly suggests an important role for SGs in the pathogenesis of PolyQ disorders. This review aims at discussing the evidence supporting the existence of a link between SGs functionality and PolyQ disorders, by focusing on the biology of SGs and on the way it can be altered in a PolyQ disease context.ALG-01-0145-FEDER-29480, SFRH/BD/133192/2017, SFRH/BD/133192/2017, SFRH/BD/148533/2019info:eu-repo/semantics/publishedVersio