Search results for "layer"

The Small Heat Shock Protein α-Crystallin B Shows Neuroprotective Properties in a Glaucoma Animal Model

2017

Glaucoma is a neurodegenerative disease that leads to irreversible retinal ganglion cell (RGC) loss and is one of the main causes of blindness worldwide. The pathogenesis of glaucoma remains unclear, and novel approaches for neuroprotective treatments are urgently needed. Previous studies have revealed significant down-regulation of α-crystallin B as an initial reaction to elevated intraocular pressure (IOP), followed by a clear but delayed up-regulation, suggesting that this small heat-shock protein plays a pathophysiological role in the disease. This study analyzed the neuroprotective effect of α-crystallin B in an experimental animal model of glaucoma. Significant IOP elevation induced b…

Activity of the α-glucoside transporter Agt1 in Saccharomyces cerevisiae cells during dehydration-rehydration events

2018

Microbial cells can enter a state of anhydrobiosis under desiccating conditions. One of the main determinants of viability during dehydration-rehydration cycles is structural integrity of the plasma membrane. Whereas much is known about phase transitions of the lipid bilayer, there is a paucity of information on changes in activity of plasma membrane proteins during dehydration-rehydration events. We selected the α-glucoside transporter Agt1 to gain insights into stress mechanisms/responses and ecophysiology during anhydrobiosis. As intracellular water content of S. cerevisiae strain 14 (a strain with moderate tolerance to dehydration-rehydration) was reduced to 1.5 g water/g dry weight, th…

Smear layer removal evaluation of different protocol of Bio Race file and XP- endo Finisher file in corporation with EDTA 17% and NaOCl.

2017

Background The aim of the present study was to compare the amount of the smear layer remaining in prepared root canals with different protocols of Bio RaCe files and XP-endo Finisher file (XPF) in association with 17% EDTA and sodium hypochlorite solution. Material and Methods A total of 68 extracted single-rooted teeth were randomly divided into 4 experimental groups (n=14) and two control groups (n=6). The root canals were prepared with Bio RaCe files (FKG Dentaire, Switzerland) using the crown-down technique based on manufacturer's instructions and irrigated according to the following irrigation techniques: Group 1: XPF with 2 mL of 2.5% NaOCl for 1 minute. Group 2:, XPF with 1 mL of 17%…

Retinal Thickness and Microvascular Pattern in Early Parkinson's Disease.

2020

A thinning of intraretinal layers has been previously described in Parkinson's disease (PD) patients compared to healthy controls (HCs). Few studies evaluated the possible correlation between retinal thickness and retinal microvascularization. Thus, here we assessed the thickness of retinal layers and microvascular pattern in early PD patients and HCs, using, respectively, spectral-domain optical coherence tomography (SD-OCT) and SD-OCT-angiography (SD-OCT-A), and more interestingly, we evaluated a possible correlation between retinal thickness and microvascular pattern. Patients fulfilling criteria for clinically established/clinically probable PD and HCs were enrolled. Exclusion criteria …

Summertime observations of ultrafine particles and cloud condensation nuclei from the boundary layer to the free troposphere in the Arctic

2016

Abstract. The Arctic is extremely sensitive to climate change. Shrinking sea ice extent increases the area covered by open ocean during Arctic summer, which impacts the surface albedo and aerosol and cloud properties among many things. In this context extensive aerosol measurements (aerosol composition, particle number and size, cloud condensation nuclei, and trace gases) were made during 11 flights of the NETCARE July, 2014 airborne campaign conducted from Resolute Bay, Nunavut (74N, 94W). Flights routinely included vertical profiles from about 60 to 3000 m a.g.l. as well as several low-level horizontal transects over open ocean, fast ice, melt ponds, and polynyas. Here we discuss the vert…

Fractional hereditariness of lipid membranes: Instabilities and linearized evolution

2016

In this work lipid ordering phase changes arising in planar membrane bilayers is investigated both accounting for elas- ticity alone and for effective viscoelastic response of such assemblies. The mechanical response of such membranes is studied by minimizing the Gibbs free energy which penalizes perturbations of the changes of areal stretch and their gradients only [1]. As material instabilities arise whenever areal stretches characterizing homogeneous configurations lie inside the spinoidal zone of the free energy density, bifurcations from such configurations are shown to occur as oscillatory perturbations of the in-plane displacement. Experimental observations [2] show a power-law in-pl…

Prospects and challenges for computer simulations of monolayer-protected metal clusters

2021

Precise knowledge of chemical composition and atomic structure of functional nanosized systems, such as metal clusters stabilized by an organic molecular layer, allows for detailed computational work to investigate structure-property relations. Here, we discuss selected recent examples of computational work that has advanced understanding of how these clusters work in catalysis, how they interact with biological systems, and how they can make self-assembled, macroscopic materials. A growing challenge is to develop effective new simulation methods that take into account the cluster-environment interactions. These new hybrid methods are likely to contain components from electronic structure t…

Interaction of C 60 fullerenes with asymmetric and curved lipid membranes: a molecular dynamics study

2015

Interaction of fullerenes with asymmetric and curved DOPC/DOPS bicelles is studied by means of coarse-grained molecular dynamics simulations. The effects caused by asymmetric lipid composition of the membrane leaflets and the curvature of the membrane are analyzed. It is shown that the aggregates of fullerenes prefer to penetrate into the membrane in the regions of the moderately positive mean curvature. Upon penetration into the hydrophobic core of the membrane fullerenes avoid the regions of the extreme positive or the negative curvature. Fullerenes increase the ordering of lipid tails, which are in direct contact with them, but do not influence other lipids significantly. Our data sugges…

2018

During gastrulation, embryonic cells become specified into distinct germ layers. In mouse, this continues throughout somitogenesis from a population of bipotent stem cells called neuromesodermal progenitors (NMps). However, the degree of self-renewal associated with NMps in the fast-developing zebrafish embryo is unclear. With a genetic clone tracing method, we labelled early embryonic progenitors and find a strong clonal similarity between spinal cord and mesoderm tissues. We followed individual cell lineages by light-sheet imaging, revealing a common neuromesodermal lineage contribution to a subset of spinal cord tissue across the anterior-posterior body axis. An initial population subdiv…

2020

Purpose To investigate the retinal nerve fiber layer profile measured by optical coherence tomography and its relation to refractive error and axial length. Methods The Gutenberg Health Study is a population-based study in Mainz, Germany. At the five-year follow-up examination, participants underwent optical coherence tomography, objective refraction and biometry. Peripapillary retinal nerve fiber layer (pRNFL) was segmented using proprietary software. The pRNFL profiles were compared between different refraction groups and the angle between the maxima, i.e., the peaks of pRNFL thickness in the upper and lower hemisphere (angle between the maxima of pRNFL thickness [AMR]) was computed. Mult…