Search results for "interface"
showing 10 items of 2139 documents
Three-dimensional hydration layer mapping on the (10.4) surface of calcite using amplitude modulation atomic force microscopy
2014
Calcite, the most stable modification of calcium carbonate, is a major mineral in nature. It is, therefore, highly relevant in a broad range of fields such as biomineralization, sea water desalination and oil production. Knowledge of the surface structure and reactivity of the most stable cleavage plane, calcite (10.4), is pivotal for understanding the role of calcite in these diverse areas. Given the fact that most biological processes and technical applications take place in an aqueous environment, perhaps the most basic - yet decisive - question addresses the interaction of water molecules with the calcite (10.4) surface. In this work, amplitude modulation atomic force microscopy is used…
Clear signature of the (2 x 1) reconstruction of calcite (1014).
2010
Calcite is a mineral of fundamental importance that plays a crucial role in many fields of research such as biomineralization, biomolecule adsorption, and reactivity as well as industrial and daily life applications. Consequently, the most stable cleavage plane of calcite has been studied extensively using both direct imaging techniques such as atomic force microscopy as well as spectroscopic and diffraction techniques. Several surface structures have been reported for the (10 (1) over bar4) cleavage plane of calcite differing from the simple bulk-truncated structure and an ongoing controversy exists in literature whether the cleavage plane exhibits a (2 x 1) reconstruction or not. We study…
Aqueous two-phase system cold-set gelation using natural and recombinant probiotic lactic acid bacteria as a gelling agent
2016
The present study aimed to entrap probiotic lactic acid bacteria (LAB) in a sodium alginate and sodium caseinate aqueous two-phase gel system. The natural acidifying properties of two therapeutic probiotic LAB were exploited to liberate calcium ions progressively from calcium carbonate (CaCO3), which caused the gelation of the co-existing phases. Bi-biopolymeric matrix gelation of GDL/CaCO3 or LAB/CaCO3 was monitored by dynamic rheological measurements, and the final gels were characterized by frequency dependence measurements and confocal laser scanning microscopy. Weak to strong gels were formed with an elastic modulus G' from 10 to 1.000Pa, respectively. After cold-set gelation of our sy…
Managing Multi-center Flow Cytometry Data for Immune Monitoring.
2014
With the recent results of promising cancer vaccines and immunotherapy 1 – 5 , immune monitoring has become increasingly relevant for measuring treatment-induced effects on T cells, and an essential tool for shedding light on the mechanisms responsible for a successful treatment. Flow cytometry is the canonical multi-parameter assay for the fine characterization of single cells in solution, and is ubiquitously used in pre-clinical tumor immunology and in cancer immunotherapy trials. Current state-of-the-art polychromatic flow cytometry involves multi-step, multi-reagent assays followed by sample acquisition on sophisticated instruments capable of capturing up to 20 parameters per cell at a…
Observations and snow model simulations of winter energy balance terms within and between different coniferous forests in Southern Boreal Finland
2015
Variation of canopy properties between different forest types is seldom taken into account in hydrological and climate models, and consideration of variation inside a forest is normally omitted. In this work, three data sets on near surface energy balance terms (incoming shortwave and longwave radiation; air and snow–soil interface temperatures) were collected in the southern boreal coniferous zone in Finland during three winters below different types of forest canopies. The aim was to evaluate the ability of a snow mass and energy balance model with a canopy module to reproduce the observed differences in below-canopy incoming radiations and snow–soil interface temperature. Clear differenc…
Airborne measurement of hot spot reflectance signatures
2004
The so-called hot spot is a fine directional signature of the surface reflectance observed for phase angles close to zero. In this paper, we analyze and discuss several such signatures acquired from the airborne POLDER and HyMap instruments during the DAISEX'99 campaign over agricultural crops. The observed signatures are very similar to those acquired from space at a resolution of several tens of kilometers [J. Geophys. Res. 107 (2002)], which provides further evidence that the hot spot is a scale-free feature. The hot spots can be fitted by a two-parameter function (amplitude and width) of the phase angle derived from canopy radiative transfer modeling. The model predicts that the amplitu…
Temperature and time dependent electron trapping in Al2O3 thin films onto AlGaN/GaN heterostructures
2022
In this article, the charge trapping phenomena in Al2O3 thin films grown by atomic layer deposition (ALD) on AlGaN/GaN heterostructures have been studied by time-dependent capacitance–voltage (C-V) measurements as a function of temperature. In particular, monitoring the transient of the capacitance enabled us to estimate the maximum depth of the insulating layer interested by the negative charge trapping effect under our bias stress conditions and to determine a charge traps density in the bulk Al2O3 in the order of 3 × 1019 cm−3. A temperature dependent C-V analysis up to 150 °C demonstrated the presence of two competitive mechanisms that rule the electron capture and emission in the Al2O3…
Real-time microfluorescence studies of Langmuir-Blodgett deposition: Monolayer adsorption and desorption
1990
Abstract Observations of the meniscus region in a typical Langmuir-Blodgett configuration are obtained using fluorescence microscopy. Studies of the meniscus position as a function of pH demonstrate that the meniscus height increases upon charging the monolayer owing to the repulsive interaction between monolayer and substrate surfaces. Through the correspondence between meniscus height and contact angle the adhesion forces between monolayer and substrate as a function of monolayer charge are assessed. The phenomenon of desorption upon resubmerging a deposited film is described and it is shown that the meniscus height at the onset of the desorption is greater for higher pH.
Mixed Ligand Shell Formation upon Catechol Ligand Adsorption on Hydrophobic TiO2 Nanoparticles
2019
Modifying the surfaces of metal oxide nanoparticles (NPs) with monolayers of ligands provides a simple and direct method to generate multifunctional coatings by altering their surface properties. T...
Comparative analysis of virtual screening approaches in the search for novel EphA2 receptor antagonists
2015
The EphA2 receptor and its ephrin-A1 ligand form a key cell communication system, which has been found overexpressed in many cancer types and involved in tumor growth. Recent medicinal chemistry efforts have identified bile acid derivatives as low micromolar binders of the EphA2 receptor. However, these compounds suffer from poor physicochemical properties, hampering their use in vivo. The identification of compounds able to disrupt the EphA2-ephrin-A1 complex lacking the bile acid scaffold may lead to new pharmacological tools suitable for in vivo studies. To identify the most promising virtual screening (VS) protocol aimed at finding novel EphA2 antagonists, we investigated the ability of…