Search results for "Microscopy"
showing 10 items of 3390 documents
Candida albicans ABG1 gene is involved in endocytosis.
2009
The human fungal pathogen Candida albicans undergoes reversible morphogenetic transitions between yeast, hyphal and pseudohyphal forms. The fungal vacuole actively participates in differentiation processes and plays a key role supporting hyphal growth. The ABG1 gene of C. albicans encodes an essential protein located in the vacuolar membranes of both yeast and hyphae. Using fluorescence microscopy of a green fluorescent protein-tagged version of Abg1p, a fraction of the protein was detected in hyphal tips, not associated with vacuolar membranes. Live cell imaging of emerging germ tubes showed that Abg1p migrated to the polarized growth site and colocalized with endocytic vesicles. Phenotypi…
Protective effect of mesoporous silica particles on encapsulated folates.
2016
Mesoporous silica particles (MSPs) are considered suitable supports to design gated materials for the encapsulation of bioactive molecules. Folates are essential micronutrients which are sensitive to external agents that provoke nutritional deficiencies. Folates encapsulation in MSPs to prevent degradation and to allow their controlled delivery is a promising strategy. Nevertheless, no information exists about the protective effect of MSPs encapsulation to prevent their degradation. In this work, 5-formyltetrahydrofolate (FO) and folic acid (FA) were entrapped in MSPs functionalized with polyamines, which acted as pH-dependent molecular gates. The stability of free and entrapped vitamins af…
Amidase-responsive controlled release of antitumoral drug into intracellular media using gluconamide-capped mesoporous silica nanoparticles
2012
MCM-41 silica nanoparticles were used as inorganic scaffolding to prepare a nanoscopic-capped hybrid material S1, which was able to release an entrapped cargo in the presence of certain enzymes, whereas in the absence of enzymes, a zero release system was obtained. S1 was prepared by loading nanoparticles with Safranine O dye and was then capped with a gluconamide derivative. In the absence of enzymes, the release of the dye from the aqueous suspensions of S1 was inhibited as a result of the steric hindrance imposed by the bulky gluconamide derivative, the polymerized gluconamide layer and the formation of a dense hydrogen-bonded network around the pore outlets. Upon the addition of amidase…
Stability of different mesoporous silica particles during an in vitro digestion
2016
Mesoporous silica materials have the ability to entrap drugs, nutrients and functional biomolecules and can be able to act as smart delivery systems capable to control and target the release of their cargo in a particular part of the gastrointestinal tract when administrated orally. However, the aptness of these encapsulation supports in in vivo oral controlled release relies on their chemical stability through the digestive tube. In this context, we have evaluated the stability of four different mesoporous silica particles, frequently used as encapsulating supports, during an in vitro digestion process comprising buccal, stomach and intestinal phases. Results showed that after 4 h of diges…
Fluorogenic Sensing of Carcinogenic Bisphenol A using Aptamer-Capped Mesoporous Silica Nanoparticles
2017
[EN] Mesoporous silica nanoparticles loaded with rhodamine B and capped with a bisphenol A aptamer were used for the selective and sensitive detection of this lethal chemical. The pores of the nanoparticles are selectively opened in the presence of bisphenol A (through its selective coordination with the aptamer) with subsequent rhodamine B delivery. With this capped material a limit of detection as low as 3.5 mu m of bisphenol A was measured.
Microradiography and confocal laser scanning microscopy applied to enamel lesions formed in vivo with and without fluoride varnish treatment
1996
The aim of the present investigation was to combine 2 techniques suitable for lesion characterization: quantitative microradiography (TMR) and confocal laser scanning microscopy (CLSM) on in vivo induced lesions with and without a fluoride varnish (Duraphat(R)) treatment. Orthodontic bands were attached to premolars to be extracted for orthodontic reasons to induce enamel caries on the buccal surfaces. In the caries development part of the study, 1 tooth of each pair received at the start 1 topical application with the fluoride varnish Duraphat(R), the contralateral tooth serving as untreated control. All teeth were extracted after 4 weeks. In the caries progression part, the premolars were…
A Highly Luminescent Nitrogen-Doped Nanographene as an Acid- and Metal-Sensitive Fluorophore for Optical Imaging.
2021
Dibenzo[hi,st]ovalene (DBOV) has excellent photophysical properties, including strong fluorescence and high ambient stability. Moreover, the optical blinking properties of DBOV have enabled optical super-resolution single-molecule localization microscopy with an imaging resolution beyond the diffraction limit. Various organic and inorganic fluorescent probes have been developed for super-resolution imaging, but those sensitive to pH and/or metal ions have remained elusive. Here, we report a diaza-derivative of DBOV (N-DBOV), synthesized in eight steps with a total yield of 15%. Nitrogen (N)-bearing zigzag edges were formed through oxidative cyclization of amino groups in the last step. UV-v…
Depth profiles of aggregate centers and nanodefects in LiF crystals irradiated with 34 MeV 84Kr, 56 MeV 40Ar and 12 MeV 12C ions
2018
I. Manika, J. Maniks and R. Zabels acknowledge the national project IMIS2. A. Dauletbekova, A. Akilbekov, M. Zdorovets and A. Seitbayev acknowledge the GF AP05134257of Ministry of Education and Science the Republic of Kazakhstan.
Carbon Nanotubes Dispersion Assessment in Nanocomposites by Means of a Pulsed Thermographic Approach
2020
The extensive production of polymer composites reinforced by carbon nanotube is limited by the absence of non-destructive evaluation (NDE) methods capable of assessing product quality to guarantee compliance with specifications. It is well known that the level of dispersion of carbon nanotubes (CNTs) in the polymer matrix is the parameter that, much more than others, can influence their enhancement capabilities. Here an active Infrared Thermography Non Destructive Testing(IR-NDT) inspection, joined with pulsed phase thermography (PPT), were applied for the first time to epoxy-CNT composites to evaluate the level of dispersion of the nanoparticles. The PPT approach was tested on three groups…
Exploring the atomic structure of 1.8 nm monolayer-protected gold clusters with aberration-corrected STEM
2017
Abstract Monolayer-protected (MP) Au clusters present attractive quantum systems with a range of potential applications e.g. in catalysis. Knowledge of the atomic structure is needed to obtain a full understanding of their intriguing physical and chemical properties. Here we employed aberration-corrected scanning transmission electron microscopy (ac-STEM), combined with multislice simulations, to make a round-robin investigation of the atomic structure of chemically synthesised clusters with nominal composition Au 144 (SCH 2 CH 2 Ph) 60 provided by two different research groups. The MP Au clusters were “weighed” by the atom counting method, based on their integrated intensities in the high …