scholarly journals Local Surface Electric Field’s Effect on Adsorbed Proteins’ Orientation

Surfaces ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 415-431 ◽  
Author(s):  
Larbi Filali ◽  
Yamina Brahmi ◽  
Jamal Dine Sib ◽  
Yahya Bouizem ◽  
Djamel Benlakehal ◽  
...  
Keyword(s):  
Electric Fields ◽  
Electrostatic Interactions ◽  
Nanocrystalline Silicon ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Adsorbed Protein ◽  
Adsorbed Proteins ◽  
Amorphous Structures ◽  
Protein Surface Interactions

Hydrogenated nanocrystalline silicon, while being non-charged and non-polar, could be an ideal candidate for the non-covalent and orientation-controlled immobilization of biomolecules thanks to local electric fields around nanocrystals. To that effect, the adsorption of bovine serum albumin on substrates with different densities of nanocrystals, revealed by Raman spectroscopy and X-ray diffraction, was studied using infrared spectroscopy and atomic force microscopy. It was found that the protein–surface interactions followed different mechanisms depending on the nanostructure at the surface: hydrophobic on the non-crystalline part of the surface and electrostatic around the crystalline part. These electrostatic interactions were driven by the electric fields that arose at the junction between crystalline and amorphous structures. These electric fields were found to be strong enough to interact with the amide dipoles, thereby reorienting the adsorbed protein molecules on this part of the surface. Nevertheless, the adsorbed proteins were found to be denatured, which was due to the surface chemistry, and not affected by the nanostructure.

scholarly journals New thermoplastic poly(carbonate-urethane) elastomers

2011 ◽  
Vol 13 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Anna Kultys ◽  
Magdalena Rogulska
Keyword(s):  
Soft Segment ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Melt Polymerization ◽  
Atomic Force ◽  
Amorphous Structures ◽  
A Chain ◽  
Poly Carbonate

New thermoplastic poly(carbonate-urethane) elastomersTwo series of novel thermoplastic poly(carbonate-urethane) elastomers, with different hard-segment content (30 - 60 wt %), were synthesized by melt polymerization from poly(hexane-1,6-diyl carbonate) diol of Mn= 2000 as a soft segment, 4,4'-diphenylmethane diisocyanate (MDI) or hexane-1,6-diyl diisocyanate (HDI) and 6,6'-[methylenebis(1,4-phenylenemethylenethio)]dihexan-1-ol as a chain extender. The structure and basic properties of the polymers were examined by Fourier transform infrared spectroscopy, X-ray diffraction analysis, atomic force microscopy, differential scanning calorimetry, thermogravimetric analysis, Shore hardness and tensile tests. The resulting TPUs were colorless polymers, showing almost amorphous structures. The MDI-based TPUs showed higher tensile strengths (up to 21.3 MPa vs. 15.8 MPa) and elongations at break (up to 550% vs. 425%), but poorer low-temperature properties than the HDI-based analogs.

Optical and Structural Characterization of Nanocrystalline Silicon Superlattices: Toward Nanoscale Silicon Metrology

2000 ◽  
Vol 638 ◽  
Author(s):  
Stefan Zollner ◽  
Atul Konkar ◽  
Ran Liu ◽  
Himansu Yapa ◽  
Patricia F. Dryer ◽  
...  
Keyword(s):  
Finite Size ◽  
Optical Excitation ◽  
Nanocrystalline Silicon ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Short Period ◽  
Structural Transmission ◽  
Short Period Superlattices

AbstractShort-period superlattices consisting of nanocrystalline Si wells and amorphous SiO2 barriers were analyzed using various structural (transmission electron microscopy, atomic force microscopy, and x-ray diffraction) and optical (Raman scattering and spectroscopic ellipsometry) characterization techniques. We observe parallel layers containing polycrystalline Si wells, primarily with <111> orientation, and an interesting surface morphology due to sputtering damage. Raman spectra show a redshift and broadening due to finite-size effects. The ellipsometry data can be described using the effective medium approximation (since the superlattice period is much shorter than the wavelength of the optical excitation) or a superlattice approach based on the Fresnel equations with a polycrystalline Si dielectric function.

Protein Adsorption Behaviors on PLLA Surface Studied by Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D)

2009 ◽  
Vol 610-613 ◽  
pp. 1219-1223 ◽  
Author(s):  
Rong Zeng ◽  
Yi Zhang ◽  
Mei Tu ◽  
Chang Ren Zhou
Keyword(s):  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Collagen I ◽  
Structure And Properties ◽  
Force Microscopy ◽  
Atomic Force ◽  
Adsorption Behaviors ◽  
Adsorbed Protein ◽  
Adsorbed Proteins ◽  
Afm Observation

The adsorption of two different proteins (bovine serum albumin (BSA) and collagen-I) onto poly (L-lactic acid) (PLLA) surface was investigated using quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). It’s found that protein characteristics would greatly affect the adsorption kinetics, structure and viscoelastic properties of adsorbed protein layers. Compared with BSA, collagen-I trended to form a loose, dissipative layer with a slower adsorption rate and larger adsorption reversibility, which is consistent with AFM observation. The results provided some valuable information for controlling the structure and properties of adsorbed proteins to develop an alternative surface-modification approach for biomaterials.

scholarly journals Preparation of Cellulose Films from Sustainable CO2/DBU/DMSO System

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 994 ◽  
Author(s):  
Longming Jin ◽  
Jianyun Gan ◽  
Gang Hu ◽  
Long Cai ◽  
Zaiquan Li ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Food Packaging ◽  
Solvent System ◽  
Light Transmittance ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Cellulose Films ◽  
Atomic Force ◽  
Dmso System ◽  
Amorphous Structures

Cellulose films are regarded as sustainable materials having wide applications in food packaging, separation, etc. Their preparation substantially relies on sufficient dissolution. Herein, various celluloses adequately dissolved in a new solvent system of carbon dioxide,1, 8-diazabicyclo [5.4.0] undec-7-ene and dimethyl sulfoxide (CO2/DBU/DMSO) were made in to films using different regeneration reagents. The films regenerated from ethanol and methanol presented homogeneous and smooth surfaces, while those from 5 wt % NaOH (aq.) and 5 wt % H2SO4 (aq.) showed rough surfaces, as analyzed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The films regenerated from 5 wt % NaOH (aq.) and 5 wt % H2SO4 (aq.) rendered cellulose II structures, while those regenerated from alcohols had amorphous structures as evidenced using fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) results. The films made of microcrystalline cellulose had a good light transmittance of about 90% at 800 nm with a tensile strength of 55 MPa and an elongation break of 6.5%, while those from wood pulp cellulose demonstrated satisfactory flexibility with a tensile strength of 91 MPa and an elongation break of 9.0%. This research reports a simple, environmental, and sustainable method to prepare cellulose films of good mechanical properties.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

Low Molecular Weight Microfibers with Light Sensing Properties

2017 ◽  
Vol 54 (4) ◽  
pp. 655-658
Author(s):  
Andrei Bejan ◽  
Dragos Peptanariu ◽  
Bogdan Chiricuta ◽  
Elena Bicu ◽  
Dalila Belei
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Force Microscopy ◽  
Light Sensing ◽  
Sensing Applications ◽  
Atomic Force ◽  
Low Molecular Weight Compounds

Microfibers were obtained from organic low molecular weight compounds based on heteroaromatic and aromatic rings connected by aliphatic spacers. The obtaining of microfibers was proved by scanning electron microscopy. The deciphering of the mechanism of microfiber formation has been elucidated by X-ray diffraction, infrared spectroscopy, and atomic force microscopy measurements. By exciting with light of different wavelength, florescence microscopy revealed a specific optical response, recommending these materials for light sensing applications.

Structural and Optical Properties of InAsSbBi Grown by Molecular Beam Epitaxy on Offcut GaSb Substrates

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 215
Author(s):  
Rajeev R. Kosireddy ◽  
Stephen T. Schaefer ◽  
Marko S. Milosavljevic ◽  
Shane R. Johnson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Optical Quality ◽  
X Ray Diffraction ◽  
Interface Quality ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Lateral Variations

Three InAsSbBi samples are grown by molecular beam epitaxy at 400 °C on GaSb substrates with three different offcuts: (100) on-axis, (100) offcut 1° toward [011], and (100) offcut 4° toward [011]. The samples are investigated using X-ray diffraction, Nomarski optical microscopy, atomic force microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The InAsSbBi layers are 210 nm thick, coherently strained, and show no observable defects. The substrate offcut is not observed to influence the structural and interface quality of the samples. Each sample exhibits small lateral variations in the Bi mole fraction, with the largest variation observed in the on-axis growth. Bismuth rich surface droplet features are observed on all samples. The surface droplets are isotropic on the on-axis sample and elongated along the [011¯] step edges on the 1° and 4° offcut samples. No significant change in optical quality with offcut angle is observed.

scholarly journals Ultrafine metal-polymer catalysts based on polyconjugated systems for Fisher–Tropsch synthesis

2020 ◽  
Vol 92 (6) ◽  
pp. 977-984
Author(s):  
Mayya V. Kulikova ◽  
Albert B. Kulikov ◽  
Alexey E. Kuz’min ◽  
Anton L. Maximov
Keyword(s):  
Tropsch Synthesis ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
Force Microscopy ◽  
Composite Catalysts ◽  
Fe Catalyst ◽  
Atomic Force ◽  
And Function ◽  
Metal Polymer

AbstractFor previously studied Fischer–Tropsch nanosized Fe catalyst slurries, polymer compounds with or without polyconjugating structures are used as precursors to form the catalyst nanomatrix in situ, and several catalytic experiments and X-ray diffraction and atomic force microscopy measurements are performed. The important and different roles of the paraffin molecules in the slurry medium in the formation and function of composite catalysts with the two types of aforementioned polymer matrices are revealed. In the case of the polyconjugated polymers, the alkanes in the medium are “weakly” coordinated with the metal-polymer composites, which does not affect the effectiveness of the polyconjugated polymers. Otherwise, alkane molecules form a “tight” surface layer around the composite particles, which create transport complications for the reagents and products of Fischer-Tropsch synthesis and, in some cases, can change the course of the in situ catalyst formation.

scholarly journals Influence of Growth Temperature of the Nucleation Layer on the Growth of InP on Si (001)

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 823
Author(s):  
Shizheng Yang ◽  
Hongliang Lv ◽  
Likun Ai ◽  
Fangkun Tian ◽  
Silu Yan ◽  
...  
Keyword(s):  
Growth Temperature ◽  
Wafer Level ◽  
X Ray Diffraction ◽  
Nucleation Layer ◽  
Force Microscopy ◽  
Gas Source ◽  
Atomic Force ◽  
Growth Method ◽  
Step Growth ◽  
Microscopy Images

InP layers grown on Si (001) were achieved by the two-step growth method using gas source molecular beam epitaxy. The effects of growth temperature of nucleation layer on InP/Si epitaxial growth were investigated systematically. Cross-section morphology, surface morphology and crystal quality were characterized by scanning electron microscope images, atomic force microscopy images, high-resolution X-ray diffraction (XRD), rocking curves and reciprocal space maps. The InP/Si interface and surface became smoother and the XRD peak intensity was stronger with the nucleation layer grown at 350 °C. The Results show that the growth temperature of InP nucleation layer can significantly affect the growth process of InP film, and the optimal temperature of InP nucleation layer is required to realize a high-quality wafer-level InP layers on Si (001).

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