Search results for "mechanical"
showing 10 items of 5999 documents
Can life be standardized? Current challenges in biological standardization
2021
The concept of standard strongly evokes machines, industries, electric or mechanical devices, vehicles, or furniture. Indeed, our technological civilization would not be possible – at least in the terms it is structured today – without universal, reliable components, whose acknowledged use results in competitive costs, robustness and interchangeability. For example, an Ikea screw can be used in a wide set of structurally dissimilar furniture and an app can be run on many different smartphones. The very concept of standardization is linked to the industrial revolution and mass production of goods through assembly lines. The question we will try to answer in the present paper is the extent to…
Evaluation of permeability applicability based on continuum mechanics law in fluid flow through graphene membrane
2019
AbstractGraphene is expected to be used in separation applications such as desalination. However, it is difficult to predict the flow phenomena at the nanoscale using the conventional continuum law. Particularly at a Knudsen number (Kn) of >0.1, which is applied in filtration, it has been reported that not even slip boundary conditions can be applied. In this study, to identify the parameters that affect the applicability of the continuum law, we conducted a fluid permeation simulation using graphene. The deviation of the permeability from that of the continuum model was calculated by changing the channel width, fluid temperature, and fluid type. The result showed that the channel width …
Role of oxidative stress in neonatal respiratory distress syndrome
2019
Respiratory distress syndrome is the commonest respiratory disorder in preterm infants. Although it is well known that preterm birth has a key role, the mechanisms of lung injury have not been fully elucidated. The pathogenesis of this neonatal condition is based on the rapid formation of the oxygen reactive species, which surpasses the detoxification capacity of anti-oxidative defense system. The high reactivity of free radical leads to damage to a variety of molecules and may induce respiratory cell death. There is evidence that the oxidative stress involved in the physiopathology of this disease, is particularly related to oxygen supplementation, mechanical ventilation, inflammation/infe…
Innovative technologies for food preservation
2018
Abstract Several techniques have been developed during the 20th century in order to preserve foods. These innovative technologies vary considerably and embrace physical technologies (e.g., high hydrostatic pressure and high-pressure homogenization), electromagnetic technologies (e.g., pulsed electric fields, ohmic heating, microwaves, radio-frequency, and UV-light), acoustic technologies (e.g., ultrasound and shockwaves), and others such as membrane filtration and dense phase CO 2 . In this chapter, the theoretical background and definition of the technologies are explained together with a description of the equipment, main technological/processing parameters, and some advantages and limita…
CXCL5, CXCL8, and CXCL10 regulation by bacteria and mechanical forces in periodontium.
2021
Made available in DSpace on 2021-06-25T10:46:01Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-01 Objective: The aim of the present study was to evaluate the expressions of CXCL5, CXCL8, and CXCL10 in periodontal cells and tissues in response to microbial signals and/or biomechanical forces. Methods: Human gingival biopsies from inflamed and healthy sites were used to examine the chemokine expressions and protein levels by real-time PCR and immunohistochemistry. The chemokines were also investigated in gingival biopsies from rats submitted to experimental periodontitis and/or tooth movement. Furthermore, chemokine levels were determined in human periodontal fibroblasts stimulated…
Parametrical Optomechanical Oscillations in PhoXonic Whispering Gallery Mode Resonators
2019
AbstractWe report on the experimental and theoretical analysis of parametrical optomechanical oscillations in hollow spherical phoxonic whispering gallery mode resonators due to radiation pressure. The optically excited acoustic eigenmodes of the phoxonic cavity oscillate regeneratively leading to parametric oscillation instabilities.
Cell stimulation versus cell death induced by sequential treatments with pulsed electric fields and cold atmospheric pressure plasma
2018
Pulsed electric fields (PEFs) and cold atmospheric pressure plasma (CAP) are currently both investigated for medical applications. The exposure of cells to PEFs can induce the formation of pores in cell membranes and consequently facilitate the uptake of molecules. In contrast, CAP mainly acts through reactive species that are generated in the liquid environment. The objective of this study was to determine, if PEFs combined with plasma-treated cell culture medium can mutually reinforce effects on viability of mammalian cells. Experiments were conducted with rat liver epithelial WB-F344 cells and their tumorigenic counterpart WB-ras for a direct comparison of non-tumorigenic and tumorigenic…
Release of copper-amended particles from micronized copper-pressure-treated wood during mechanical abrasion
2016
Background We investigated the particles released due to abrasion of wood surfaces pressure-treated with micronized copper azole (MCA) wood preservative and we gathered preliminary data on its in vitro cytotoxicity for lung cells. The data were compared with particles released after abrasion of untreated, water (0% MCA)-pressure-treated, chromated copper (CC)-pressure-treated wood, and varnished wood. Size, morphology, and composition of the released particles were analyzed. Results Our results indicate that the abrasion of MCA-pressure-treated wood does not cause an additional release of nanoparticles from the unreacted copper (Cu) carbonate nanoparticles from of the MCA formulation. Howev…
Regulation of Autophagic Signaling by Mechanical Loading and Inflammation in Human PDL Fibroblasts
2020
Autophagy (cellular self-consumption) is a crucial adaptation mechanism during cellular stress conditions. This study aimed to examine how this important process is regulated in human periodontal ligament (PDL) fibroblasts by mechanical and inflammatory stress conditions and whether the mammalian target of rapamycin (mTOR) signaling pathway is involved. Autophagy was quantified by flow cytometry. Qualitative protein phosphorylation profiling of the mTOR pathway was carried out. Effects of mTOR regulation were assessed by quantification of important synthesis product collagen 1, cell proliferation and cell death with real-time PCR and flow cytometry. Autophagy as a response to mechanical or …
Unveiling the evolution of bivalve nacre proteins by shell proteomics of Unionoidae.
2015
The formation of the molluscan shell nacre is regulated to a large extent by a matrix of extracellular macromolecules that are secreted by the shell forming tissue, the mantle. This so called “calcifying matrix” is a complex mixture of proteins and glycoproteins that is assembled and occluded within the mineral phase during the calcification process. While the importance of the calcifying matrix to shell formation has long been appreciated, the molecular basis that dictates nacre formation remains largely uncharacterized.Recent expressed sequence tag (EST) investigations of the freshwater mussels (Elliptio complanata and Villosa leinosa) provide an opportunity to further characterize the pr…