scholarly journals Effective intercalation of zein into Na-montmorillonite: role of the protein components and use of the developed biointerfaces

2016 ◽  
Vol 7 ◽  
pp. 1772-1782 ◽  
Author(s):  
Ana C S Alcântara ◽  
Margarita Darder ◽  
Pilar Aranda ◽  
Eduardo Ruiz-Hitzky
Keyword(s):  
Water Solution ◽  
Physicochemical Characterization ◽  
Layered Silicate ◽  
Aqueous Dispersion ◽  
Underlying Mechanism ◽  
Ethanol Medium ◽  
Major Storage Protein ◽  
Protein Components

Biohybrid materials based on the intercalation of zein, the major storage protein in corn, into sodium-exchanged montmorillonite were prepared following two synthesis strategies. The first one made use of zein dissolved in 80% (v/v) ethanol/water solution, the usual solvent for this protein, while the second method is new and uses a sequential process that implies the previous separation of zein components in absolute ethanol. This treatment of zein with ethanol renders a soluble yellow phase and an agglomerate of insoluble components, which are able to intercalate the layered silicate when an aqueous dispersion of montmorillonite is added to the ethanol medium containing both phases. The diverse steps in this second route were investigated individually in order to understand the underlying mechanism that drives to the intercalation of this complex hydrophobic biomacromolecule into the hydrophilic interlayer space of sodium-exchanged montmorillonite. In addition to physicochemical characterization of the resulting materials, these biohybrid interfaces were also evaluated as biofillers in the preparation of diverse ecofriendly nanocomposites.

scholarly journals THE PREPARATION AND PHYSICOCHEMICAL CHARACTERIZATION OF THE SERUM PROTEIN COMPONENTS OF COMPLEMENT

1941 ◽  
Vol 74 (4) ◽  
pp. 297-308 ◽  
Author(s):  
L. Pillemer ◽  
E. E. Ecker ◽  
J. L. Oncley ◽  
E. J. Cohn
Keyword(s):  
Ionic Strength ◽  
Guinea Pig ◽  
Potassium Chloride ◽  
Electrophoretic Mobility ◽  
Phosphate Buffer ◽  
Physicochemical Characterization ◽  
Sedimentation Constant ◽  
Protein Components ◽  
Pig Serum

1. Methods for the separation from guinea pig serum in highly purified form of three of the components of complement are described. These substances are the so called mid-piece, end-piece, and 4th component. 2. Mid-piece has been separated as a euglobulin, with an electrophoretic mobility of 2.9 x 10–5 in phosphate buffer of ionic strength 0.2 at pH 7.7, and with a sedimentation constant of 6.4 x 10–13 in potassium chloride of ionic strength 0.2. 3. End-piece and 4th component were found together in a euglobulin fraction of serum which contained 10.3 per cent carbohydrate and had an electrophoretic mobility of 4.2 x 10–5 in phosphate buffer of ionic strength 0.2 at pH 7.7.

scholarly journals An Update on the Role of the Actin Cytoskeleton in Plasmodesmata: A Focus on Formins

2021 ◽  
Vol 12 ◽  
Author(s):  
Min Diao ◽  
Shanjin Huang
Keyword(s):  
Plant Growth ◽  
Actin Cytoskeleton ◽  
Growth And Development ◽  
Cell Communication ◽  
Underlying Mechanism ◽  
Review Article ◽  
Plant Growth And Development ◽  
Shed Light

Cell-to-cell communication in plants is mediated by plasmodesmata (PD) whose permeability is tightly regulated during plant growth and development. The actin cytoskeleton has been implicated in regulating the permeability of PD, but the underlying mechanism remains largely unknown. Recent characterization of PD-localized formin proteins has shed light on the role and mechanism of action of actin in regulating PD-mediated intercellular trafficking. In this mini-review article, we will describe the progress in this area.

scholarly journals Ru@hyperbranched Polymer for Hydrogenation of Levulinic Acid to Gamma-Valerolactone: The Role of the Catalyst Support

2022 ◽  
Vol 23 (2) ◽  
pp. 799
Author(s):  
Svetlana A. Sorokina ◽  
Stepan P. Mikhailov ◽  
Nina V. Kuchkina ◽  
Alexey V. Bykov ◽  
Alexander L. Vasiliev ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Catalyst Support ◽  
Physicochemical Characterization ◽  
Significant Loss ◽  
Catalyst Loading ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Low Catalyst Loading

Hydrogenation of levulinic acid (LA) obtained from cellulose biomass is a promising path for production of γ-valerolactone (GVL)—a component of biofuel. In this work, we developed Ru nanoparticle containing nanocomposites based on hyperbranched pyridylphenylene polymer, serving as multiligand and stabilizing matrix. The functionalization of the nanocomposite with sulfuric acid significantly enhances the activity of the catalyst in the selective hydrogenation of LA to GVL and allows the reaction to proceed under mild reaction conditions (100 °C, 2 MPa of H2) in water and low catalyst loading (0.016 mol.%) with a quantitative yield of GVL and selectivity up to 100%. The catalysts were successfully reused four times without a significant loss of activity. A comprehensive physicochemical characterization of the catalysts allowed us to assess structure-property relationships and to uncover an important role of the polymeric support in the efficient GVL synthesis.

Physicochemical Characterization of Inorganic Pigments in the Presence of Gaseous Pollutants. The Role of Ozone

2002 ◽  
Vol 216 (11) ◽  
Author(s):  
V. Siokos ◽  
J. Kapolos ◽  
F. Roubani-Kalantzopoulou
Keyword(s):  
Gas Chromatography ◽  
Physicochemical Characterization ◽  
Gaseous Pollutants ◽  
Inorganic Pigments ◽  
Reversed Flow ◽  
Volatile Hydrocarbons

The Reversed–Flow Gas Chromatography technique was used to study the interaction of volatile hydrocarbons on three inorganic pigments, namely, CdS, ZnS and Cr

The modulation of physicochemical characterization of innovative liposomal platforms: the role of the grafted thermoresponsive polymers

2015 ◽  
Vol 22 (3) ◽  
pp. 330-335 ◽  
Author(s):  
Maria Chountoulesi ◽  
Aimilia Kyrili ◽  
Natassa Pippa ◽  
Anastasia Meristoudi ◽  
Stergios Pispas ◽  
...  
Keyword(s):  
Physicochemical Characterization ◽  
Thermoresponsive Polymers

scholarly journals Crystal structure of the inclusion complex of cholesterol in β-cyclodextrin and molecular dynamics studies

2018 ◽  
Vol 14 ◽  
pp. 838-848 ◽  
Author(s):  
Elias Christoforides ◽  
Andreas Papaioannou ◽  
Kostas Bethanis
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Mammalian Cells ◽  
Inclusion Compound ◽  
Physicochemical Characterization ◽  
Md Simulations ◽  
Cholesterol Removal ◽  
Triclinic Space Group

The role of beta-cyclodextrin (β-CD) in cholesterol removal primarily from mammalian cells and secondly from dairy products has been studied thoroughly in recent years. Although the physicochemical characterization of the inclusion compound of cholesterol in β-CD has been achieved by various methods, no crystal structure has been determined so far. We report here the crystal structure of the inclusion compound of cholesterol in β-CD. The inclusion complex crystallizes in the triclinic space group P1 forming head-to-head dimers which are stacked along the c-axis. One well-defined cholesterol molecule ‘axially’ encapsulated inside the β-CD dimer and 22 water molecules that stabilize the complexes in the crystalline state comprise the asymmetric unit of the structure. The dimers are arranged in an intermediate (IM) channel packing mode in the crystal. Moreover, MD simulations, at 300 and 340 K, based on the crystallographically determined coordinates of the complex show that the formed cholesterol/β-CD inclusion compound remains very stable in aqueous solution at both temperatures.

Digital x-ray mapping of nanometer-size supported bimetallic catalysts

1988 ◽  
Vol 46 ◽  
pp. 530-531
Author(s):  
L. T. Germinario
Keyword(s):  
Background Radiation ◽  
Metal Cluster ◽  
Single Element ◽  
Beam Diameter ◽  
X Rays ◽  
X Ray ◽  
Major Interest ◽  
Induced Changes

Understanding the role of metal cluster composition in determining catalytic selectivity and activity is of major interest in heterogeneous catalysis. The electron microscope is well established as a powerful tool for ultrastructural and compositional characterization of support and catalyst. Because the spatial resolution of x-ray microanalysis is defined by the smallest beam diameter into which the required number of electrons can be focused, the dedicated STEM with FEG is the instrument of choice. The main sources of errors in energy dispersive x-ray analysis (EDS) are: (1) beam-induced changes in specimen composition, (2) specimen drift, (3) instrumental factors which produce background radiation, and (4) basic statistical limitations which result in the detection of a finite number of x-ray photons. Digital beam techniques have been described for supported single-element metal clusters with spatial resolutions of about 10 nm. However, the detection of spurious characteristic x-rays away from catalyst particles produced images requiring several image processing steps.

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