Search results for "Scanning"
showing 10 items of 1808 documents
The actin-based motility of intracellularListeria monocytogenesis not controlled by small GTP-binding proteins of the Rho- and Ras-subfamilies
1999
In this study, we analyzed whether the actin-based motility of intracellular Listeria monocytogenes is controlled by the small GTP-binding proteins of the Rho- and Ras-subfamilies. These signalling proteins are key regulatory elements in the control of actin dynamics and their activity is essential for the maintenance of most cellular microfilament structures. We used the Clostridium difficile toxins TcdB-10463 and TcdB-1470 to specifically inactivate these GTP-binding proteins. Treatment of eukaryotic cells with either of these toxins led to a dramatic breakdown of the normal actin cytoskeleton, but did not abrogate the invasion of epithelial cells by L. monocytogenes and had no effect on …
A new biodegradable and biocompatible hydrogel with polyaminoacid structure
2007
The preparation and physicochemical and biological characterization of a novel polyaminoacid hydrogel have been reported. The ,-poly(N-2- hydroxyethyl)-dl-aspartamide (PHEA) has been used as a starting polymer for a derivatization reaction with methacrylic anhydride (MA) to give rise to the methacrylate derivative named PHM. Photocrosslinking of PHM has been performed in aqueous solution at 313 nm and in the absence of toxic initiators. PHM-based hydrogel has been characterized by scanning electron microscopy, X-ray diffractometry, swelling measurements in aqueous media; the degradation of PHM-based hydrogel has been evaluated as a function of time in the absence or in the presence of ester…
Cytotoxicity and bioactivity of various pulpotomy materials on stem cells from human exfoliated primary teeth.
2017
Aims To investigate the cytotoxicity and bioactivity of several pulpotomy materials: Biodentine (Septodont, Saint-Maur-des-Fosses, France) MTA (Angelus, Londrina, PR, Brazil), Theracal LC (Bisco Inc., Schamburg, IL, USA) and IRM (Dentsply DeTrey GmbH, Konstanz, Germany), after contact with stem cells isolated from human exfoliated primary teeth (SHEDs). Methodology SHEDs were cultured in the presence of the eluates of various pulpotomy materials for 24, 48 and 72 h. Cell viability was determined by mitochondrial dehydrogenase enzymatic (MTT) assay. Apoptosis and changes in cell phenotype were evaluated by flow cytometry. Also, an in vitro scratch wound-healing assay was used to determine th…
The effect of ions at the surface of calcium oxalate monohydrate crystals on cell-crystal interactions
2003
Magnesium is an abundant ion in biologic systems, including renal tubular fluid; however, the precise role of magnesium during the interaction of calcium oxalate crystals with cells has not been previously defined. In addition, the respective roles of calcium and hydrogen ions during the cell-crystal bonding interaction remain poorly defined. Here we report an atomic level three-dimensional study of a single crystal of calcium oxalate monohydrate (COM; whewellite) which was bathed in a solution of magnesium hexahydrate for 1 year. Magnesium was not incorporated into the structure of whewellite to any significant degree. Instead, COM accepted magnesium primarily as an adsorbate in a binding …
In vitro degradation of porous PLLA/pearl powder composite scaffolds
2013
Abstract The in vitro degradation behavior of poly- l -lactide (PLLA), PLLA/aragonite pearl powder and PLLA/vaterite pearl powder scaffolds was investigated. The scaffolds were soaked in phosphate buffer solution (PBS) up to 200 days. Scanning electron microscopy (SEM), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) were used to observe any degradation of the scaffolds. Degradation behaviors such as changes in pH, porosity, bulk density, water absorption, weight loss and mechanical properties were discussed. The results show that a gradual increase of the pH in composite scaffolds can decrease the rate of hydrolysis of PLLA. PLLA/vaterite and PLLA/aragonite…
Cariostatic effect of a light-cured, resin-reinforced glass-ionomer for bonding orthodontic brackets in vivo
1998
The aim of this study was to evaluate in vivo the cariostatic potential of the resin-reinforced glass-ionomer (Vitremer core build-up restorative; 3M Dental Product Division) when used as a bonding agent for orthodontic brackets. The mineral distribution and topography of the enamel surface adjacent to the bracket base was determined by quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM). The study was designed in split-mouth technique using 9 pairs of premolars to be extracted for orthodontic reasons. One tooth of each pair was bonded with the resin-reinforced glass-ionomer, and the control contralateral premolar with the non-fluoridated composite (Concise, 3M…
Fennel waste-based films suitable for protecting cultivations.
2007
Biodegradable, flexible, and moisture-resistant films were obtained by recycling fennel waste and adding to fennel homogenates the bean protein phaseolin that was modified or not modified by the enzyme transglutaminase. All films were analyzed for their morphology, mechanical properties, water vapor permeability, and susceptibility to biodegradation under soil-like conditions. Our experiments showed that transglutaminase treatment of the phaseolin-containing fennel waste homogenates allowed us to obtain films comparable in their mechanical properties and water vapor permeability to the commercial films Ecoflex and Mater-Bi. Furthermore, biodegradability tests demonstrated that the presence …
Electrosynthesis of Sn-Co nanowires in alumina membranes
2010
A fabrication process of amorphous nanowires of Sn-Co alloys, based on electrodeposition into anodic alumina membranes, is described. It is shown that nanowires of tin-cobalt alloys with different compositions can be produced by varying electrodeposition time and concentration ratio of salts dissolved into the electrolytic bath. Importance of the chelating agent to produce amorphous Sn-Co alloys has also been addressed. Electrodepositions were carried out potentiostatically at -1 V versus Saturated Calomel Electrode and 60 degrees C for times ranging from 10 to 90 minutes; the atomic fraction of Co2+ in the aqueous electrolyte (Co2+/(Co2+ + Sn2+)) was varied from 0.33 to 0.67. Nanowires asp…
Cavitation corrosion and repassivation kinetics of titanium in a heavy brine LiBr solution evaluated by using electrochemical techniques and Confocal…
2011
The cavitation corrosion behaviour of commercially pure Grade 2 titanium in a 992 g/l LiBr solution has been investigated at 25 °C using an ultrasound device. Cavitation was found to have more influence on the anodic branch than on the cathodic branch, shifting the corrosion potential, Ecorr, and the OCP value towards more negative potentials, and increasing the corrosion current density, icorr, by six times. The repassivation kinetics of Grade 2 titanium have also been studied in the 992 g/l LiBr solution, at 25 °C and various applied potentials, using cavitation to damage the electrode surface. The repassivation kinetics have been analysed in terms of the current density flowing from the …
Synthesis of Mesoporous Supraparticles on Superamphiphobic Surfaces
2015
A method for mesoporous supraparticle synthesis on superamphiphobic surfaces is designed. Therefore, supraparticles assembled with nanoparticles are synthesized by the evaporation of nanoparticle dispersion drops on the superamphiphobic surface. For synthesis, no further purification is required and no organic solvents are wasted. Moreover, by changing the conditions such as drop size and concentration, supraparticles of different sizes, compositions, and architectures are fabricated.