Search results for "layer"

Ultrasonic Welding of PBT-GF30 (70% Polybutylene Terephthalate + 30% Fiber Glass) and Expanded Polytetrafluoroethylene (e-PTFE)

2021

The ultrasonic welding of polymeric materials is one of the methods often used in practice. However, each couple of material subjected to ultrasonic welding is characterized by different values of technological parameters. Therefore, the main objective of the research presented in this paper is to optimize the parameters for the ultrasonic welding of two materials, namely PBT-GF30 (70% polybutylene terephthalate + 30% fiber glass) and expanded polytetrafluoroethylene (e-PTFE). In this sense, the research was carried out considering a plate-type part made of PBT-GF30, which had a thickness of 2.1 mm, and a membrane-type part made of e-PTFE, with a thickness of 0.3 mm. The condition imposed o…

Stable layer-building strategy to enhance cold-spray-based additive manufacturing

2020

Abstract Cold spray (CS) has recently become one of the popular additive manufacturing (AM) processes for its advantages: high-forming efficiency, low temperature, and no phase changing of materials. These advantages may make CS able to form large volume objects and possibly directly iterate with material-removing processes to become a hybrid AM process. Current research proposes using a bulk-based volume-forming strategy (e.g. a tessellation-based method) for volume building. Although it can form 3D volumes, the control of the process is difficult and it has limitations in forming complex 3D near-net-shapes with acceptable accuracy. This also conflicts with the basic principle of AM, where…

The effect of photodynamic therapy and polymer solution containing nano-particles of Ag /ZnO on push-out bond strength of the sealers AH-Plus and MTA…

2017

BACKGROUND The aim of this in vitrostudy was to examine and compare the effect of photodynamic therapy and solution containing nano particles Ag/ZnO on adhesion of endodontic sealers to dentinal walls of human root canal. MATERIAL AND METHODS Ninty single-rooted human teeth were selected and their clinical crown was cut from the cemento-enamel junction zone. Canals were prepared by RaCe rotary system and the smear layer was removed using 17% EDTA and 5.25% NaOCl. Samples were randomly divided into two groups of AH Plus and MTA Fillapex based on the sealer type and each group based on antimicrobial method was divided into two sub-groups of photodynamic therapy and polymer containing nano par…

2021

Lipids contained in the plasma membrane of platelets play an important role in platelet function. Modifications in the lipid composition can fluidify or rigidify the environment around embedded receptors, in order to facilitate the access of the receptor by the drug. However, data concerning the lipid composition of platelet plasma membrane need to be updated. In addition, data on the impact of drugs on plasma membrane composition, in particular antiplatelet agents, remain sparse. After isolation of platelet plasma membrane, we assessed, using lipidomics, the effect of ticagrelor, a P2Y12 antagonist, and its active metabolite on the lipid composition of these plasma membranes. We describe t…

Palmitoylation is a post-translational modification of Alix regulating the membrane organization of exosome-like small extracellular vesicles.

2018

Abstract Background Virtually all cell types have the capacity to secrete nanometer-sized extracellular vesicles, which have emerged in recent years as potent signal transducers and cell-cell communicators. The multifunctional protein Alix is a bona fide exosomal regulator and skeletal muscle cells can release Alix-positive nano-sized extracellular vesicles, offering a new paradigm for understanding how myofibers communicate within skeletal muscle and with other organs. S-palmitoylation is a reversible lipid post-translational modification, involved in different biological processes, such as the trafficking of membrane proteins, achievement of stable protein conformations, and stabilization…

New insights into aerosol and climate in the Arctic

2018

Abstract. Motivated by the need to predict how the Arctic atmosphere will change in a warming world, this article summarizes recent advances made by the research consortium NETCARE (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) that contribute to our fundamental understanding of Arctic aerosol particles as they relate to climate forcing. The overall goal of NETCARE research has been to use an interdisciplinary approach encompassing extensive field observations and a range of chemical transport, earth system, and biogeochemical models. Several major findings and advances have emerged from NETCARE since its formation in 2013 . (1) Unexpectedly …

Structural, ultrastructural, and morphometric study of the zebrafish ocular surface: a model for human corneal diseases?

2018

Purpose: A morphological and morphometric study of the adult zebrafish ocular surface was performed to provide a comprehensive description of its parts and to evaluate its similarity to the human. Materials and Methods: The eyes of adult zebrafish were processed for light, transmission and scanning electron microscopy, and for immunohistochemical stain of corneal nerves; a morphometric analysis was also performed on several morphological parameters. Results: The corneal epithelium was formed by five layers of cells. No Bowman’s layer could be demonstrated. The stroma consisted of lamellae of different thickness with few keratocytes. The Descemet’s membrane was absent as the flat and polygon…

Outlook from the soil perspective of urban expansion and food security

2021

The use of soil as support for built-up areas represents only one of its several functions. Farmlands at the fringe of conurbations have more chance of being converted into built-up areas due to the favourable topography and the accessibility to existing infrastructure, being in the vicinity of urban areas. We analysed the global land-take during the period 2000–2014. The data are based on a global dataset describing the spatial evolution of human settlements using the Global Human Settlement Layer, which was derived from Landsat images collected in 1975, 1990, 2000 and 2014. Although the global land-take represents roughly 0.1% of the global terrestrial Earth, it affects 1% of the naturall…

Specific interaction of IM30/Vipp1 with cyanobacterial and chloroplast membranes results in membrane remodeling and eventually in membrane fusion.

2016

The photosynthetic light reaction takes place within the thylakoid membrane system in cyanobacteria and chloroplasts. Besides its global importance, the biogenesis, maintenance and dynamics of this membrane system are still a mystery. In the last two decades, strong evidence supported the idea that these processes involve IM30, the inner membrane-associated protein of 30kDa, a protein also known as the vesicle-inducing protein in plastids 1 (Vipp1). Even though we just only begin to understand the precise physiological function of this protein, it is clear that interaction of IM30 with membranes is crucial for biogenesis of thylakoid membranes. Here we summarize and discuss forces guiding I…

Toxicity and cell density monitoring in monolayer and three-dimensional cultures with the XTT assay

1998

The application of viability criteria (MTT and XTT tests) to monolayer cultures and immobilised cells in three-dimensional systems was investigated in order to assess cell viability and cell proliferation. The suitability and accuracy of these tests were compared with the conventional criteria (cellular protein and DNA content) used in monolayer cultures for the same purpose. The colorimetric assay based on the metabolic reduction of the tetrazolium salt XTT to a water-soluble formazan proved to be very useful, rapid and sensitive. This automated spectrophotometric enzymatic method, due to its lack of toxicity, also permits repeated nondestructive assays on a single cellular culture for the…