scholarly journals A New Function for Amyloid-Like Interactions: Cross-Beta Aggregates of Adhesins form Cell-to-Cell Bonds

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1013
Author(s):  
Peter N. Lipke ◽  
Marion Mathelié-Guinlet ◽  
Albertus Viljoen ◽  
Yves F. Dufrêne
Keyword(s):  
Structural Characteristics ◽  
Critical Concentration ◽  
Side Chain ◽  
Force Microscopy ◽  
Protein Molecules ◽  
New Type ◽  
In Trans ◽  
Β Sheets ◽  
Fungal Adhesins ◽  
Cell Force

Amyloid structures assemble through a repeating type of bonding called “cross-β”, in which identical sequences in many protein molecules form β-sheets that interdigitate through side chain interactions. We review the structural characteristics of such bonds. Single cell force microscopy (SCFM) shows that yeast expressing Als5 adhesin from Candida albicans demonstrate the empirical characteristics of cross-β interactions. These properties include affinity for amyloid-binding dyes, birefringence, critical concentration dependence, repeating structure, and inhibition by anti-amyloid agents. We present a model for how cross-β bonds form in trans between two adhering cells. These characteristics also apply to other fungal adhesins, so the mechanism appears to be an example of a new type of cell–cell adhesion.

High-Speed Atomic Force Microscopy for Studying the Dynamic Behavior of Protein Molecules at Work

2006 ◽  
Vol 45 (3B) ◽  
pp. 1897-1903 ◽  
Author(s):  
Toshio Ando ◽  
Takayuki Uchihashi ◽  
Noriyuki Kodera ◽  
Atsushi Miyagi ◽  
Ryo Nakakita ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Dynamic Behavior ◽  
High Speed ◽  
Force Microscopy ◽  
Atomic Force ◽  
Protein Molecules

scholarly journals Cell Force Microscopy on Elastic Layers of Finite Thickness

2007 ◽  
Vol 93 (9) ◽  
pp. 3314-3323 ◽  
Author(s):  
Rudolf Merkel ◽  
Norbert Kirchgeßner ◽  
Claudia M. Cesa ◽  
Bernd Hoffmann
Keyword(s):  
Finite Thickness ◽  
Force Microscopy ◽  
Elastic Layers ◽  
Cell Force

ChemInform Abstract: New Type of 2-Alkyl-substituted 1,8-Naphthyridine Systems Containing a Phosphoryl Group in the Side Chain.

ChemInform ◽  
2008 ◽  
Vol 39 (34) ◽  
Author(s):  
P. S. Lemport ◽  
G. V. Bodrin ◽  
M. P. Pasechnik ◽  
A. G. Matveeva ◽  
P. V. Petrovskii ◽  
...  
Keyword(s):  
Side Chain ◽  
Phosphoryl Group ◽  
New Type

scholarly journals Comprehensive Research and Analysis of a Coated Machining Tool with a New TiAlN Composite Microlayer Using Magnetron Sputtering

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3633
Author(s):  
Štefan Michna ◽  
Iryna Hren ◽  
Jan Novotný ◽  
Lenka Michnová ◽  
Václav Švorčík
Keyword(s):  
Magnetron Sputtering ◽  
Surface Defects ◽  
Light And Electron Microscopy ◽  
Cutting Tools ◽  
Microstructural Characterization ◽  
High Wear Resistance ◽  
Drilling Process ◽  
Cross Sectional ◽  
Force Microscopy ◽  
New Type

The application of thin monolayers helps to increase the endurance of a cutting tool during the drilling process. One such trendy coating is TiAlN, which guarantees high wear resistance and helps to “smooth out” surface defects. For this reason, a new type of weak TiAlN microlayer with a new composition has been developed and applied using the HIPIMs magnetron sputtering method. The aim of this study was to analyze surface-applied micro coatings, including chemical composition (EDX) and microstructure in the area of the coatings. Microstructural characterization and visualization of the surface structures of the TiAlN layer were performed using atomic force microscopy. To study the surface layer of the coatings, metallographic cross-sectional samples were prepared and monitored using light and electron microscopy methods. The microhardness of the test layer was also determined. Analyses have shown that a 2-to-4-micron thick monolayer has a microhardness of about 2500 HV, which can help increase the life of cutting tools.

scholarly journals Influence of the growth parameters of TiO2 thin films deposited by the MOCVD method

Cerâmica ◽  
2002 ◽  
Vol 48 (305) ◽  
pp. 38-42 ◽  
Author(s):  
M. I. B. Bernardi ◽  
E. J. H. Lee ◽  
P. N. Lisboa-Filho ◽  
E. R. Leite ◽  
E. Longo ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Parameters ◽  
Structural Characteristics ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Tio2 Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Deposition Parameters

The synthesis of TiO2 thin films was carried out by the Organometallic Chemical Vapor Deposition (MOCVD) method. The influence of deposition parameters used during growth on the final structural characteristics was studied. A combination of the following experimental parameters was studied: temperature of the organometallic bath, deposition time, and temperature and substrate type. The high influence of those parameters on the final thin film microstructure was analyzed by scanning electron microscopy with electron dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction.

scholarly journals Trans-dimerization of JAM-A regulates Rap2 and is mediated by a domain that is distinct from the cis-dimerization interface

2014 ◽  
Vol 25 (10) ◽  
pp. 1574-1585 ◽  
Author(s):  
Ana C. Monteiro ◽  
Anny-Claude Luissint ◽  
Ronen Sumagin ◽  
Caroline Lai ◽  
Franziska Vielmuth ◽  
...  
Keyword(s):  
Epithelial Cell Proliferation ◽  
Wild Type ◽  
Transfected Cells ◽  
Force Microscopy ◽  
Atomic Force ◽  
Unique Site ◽  
Dimerization Interface ◽  
In Trans ◽  
In Cis ◽  
Common Cell

Junctional adhesion molecule-A (JAM-A) is a tight junction–associated signaling protein that regulates epithelial cell proliferation, migration, and barrier function. JAM-A dimerization on a common cell surface (in cis) has been shown to regulate cell migration, and evidence suggests that JAM-A may form homodimers between cells (in trans). Indeed, transfection experiments revealed accumulation of JAM-A at sites between transfected cells, which was lost in cells expressing cis- or predicted trans-dimerization null mutants. Of importance, microspheres coated with JAM-A containing alanine substitutions to residues 43NNP45 (NNP-JAM-A) within the predicted trans-dimerization site did not aggregate. In contrast, beads coated with cis-null JAM-A demonstrated enhanced clustering similar to that observed with wild-type (WT) JAM-A. In addition, atomic force microscopy revealed decreased association forces in NNP-JAM-A compared with WT and cis-null JAM-A. Assessment of effects of JAM-A dimerization on cell signaling revealed that expression of trans- but not cis-null JAM-A mutants decreased Rap2 activity. Furthermore, confluent cells, which enable trans-dimerization, had enhanced Rap2 activity. Taken together, these results suggest that trans-dimerization of JAM-A occurs at a unique site and with different affinity compared with dimerization in cis. Trans-dimerization of JAM-A may thus act as a barrier-inducing molecular switch that is activated when cells become confluent.

scholarly journals Preparation of side chain liquid crystal polyether chelating resin and its adsorption properties for Cu2+ in water

2021 ◽  
Author(s):  
Chaoyi Qian ◽  
Meng Li ◽  
Shuang Wang ◽  
Qing Gao ◽  
Huaiwei Yao ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Influence Factors ◽  
Chelating Resin ◽  
Side Chain ◽  
Order Kinetic ◽  
Adsorption Model ◽  
Order Kinetic Model ◽  
Group A ◽  
New Type ◽  
Cationic Ring Opening Polymerization

Abstract With epoxycyclohexane as critical modifying monomer, the copolyether was obtained by cationic ring-opening polymerization of epichlorohydrin and epoxycyclohexane. Then biphenyl was used as the mesogen, and diglycolamidic acid was used as the terminal chelating group, a new type of side chain liquid crystal polyether chelating resin was prepared at last. The adsorption influence factors, reuse performance, adsorption model and adsorption kinetics of the chelated resin on Cu 2+ in water were studied systematically. The results showed that the resin has good adsorption and reuse performance for the treatment of Cu 2+ in water, and the adsorption of Cu 2+ is Langmuir monolayer adsorption, and the adsorption process conforms to a quasi-second-order kinetic model. The adsorption performances of the chelated resin has great potential for recovery of copper resource from non-ferrous smelting industry.

scholarly journals Innovative Low-Cost Carbon/ZnO Hybrid Materials with Enhanced Photocatalytic Activity towards Organic Pollutant Dyes’ Removal

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1873
Author(s):  
Petronela Pascariu ◽  
Niculae Olaru ◽  
Aurelian Rotaru ◽  
Anton Airinei
Keyword(s):  
Photocatalytic Activity ◽  
Hybrid Materials ◽  
Raw Materials ◽  
Structural Characteristics ◽  
Low Cost ◽  
Organic Pollutant ◽  
Zno Nanostructures ◽  
Zno Nanocrystals ◽  
Electrospinning Method ◽  
New Type

A new type of material based on carbon/ZnO nanostructures that possesses both adsorption and photocatalytic properties was obtained in three stages: cellulose acetate butyrate (CAB) microfiber mats prepared by the electrospinning method, ZnO nanostructures growth by dipping and hydrothermal methods, and finally thermal calcination at 600 °C in N2 for 30 min. X-ray diffraction (XRD) confirmed the structural characteristics. It was found that ZnO possesses a hexagonal wurtzite crystalline structure. The ZnO nanocrystals with star-like and nanorod shapes were evidenced by scanning electron microscopy (SEM) measurements. A significant decrease in Eg value was found for carbon/ZnO hybrid materials (2.51 eV) as compared to ZnO nanostructures (3.21 eV). The photocatalytic activity was evaluated by studying the degradation of three dyes, Methylene Blue (MB), Rhodamine B (RhB) and Congo Red (CR) under visible-light irradiation. Therefore, the maximum color removal efficiency (both adsorption and photocatalytic processes) was: 97.97% of MB (C0 = 10 mg/L), 98.34% of RhB (C0 = 5 mg/L), and 91.93% of CR (C0 = 10 mg/L). Moreover, the value of the rate constant (k) was found to be 0.29 × 10−2 min−1. The novelty of this study relies on obtaining new photocatalysts based on carbon/ZnO using cheap and accessible raw materials, and low-cost preparation techniques.

scholarly journals DFT Prediction of Factors Affecting the Structural Characteristics, the Transition Temperature and the Electronic Density of Some New Conjugated Polymers

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1207
Author(s):  
Quoc-Trung Vu ◽  
Thi-Thuy-Duong Tran ◽  
Thuy-Chinh Nguyen ◽  
Thien Vuong Nguyen ◽  
Hien Nguyen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Conjugated Polymers ◽  
Bond Length ◽  
Density Functional ◽  
Structural Characteristics ◽  
Side Chain ◽  
Electronic Density ◽  
Energy Field ◽  
Energy Bandgap

Conjugated polymers are promising materials for various cutting-edge technologies, especially for organic conducting materials and in the energy field. In this work, we have synthesized a new conjugated polymer and investigated the effect of distance between bond layers, side-chain functional groups (H, Br, OH, OCH3 and OC2H5) on structural characteristics, phase transition temperature (T), and electrical structure of C13H8OS using Density Functional Theory (DFT). The structural characteristics were determined by the shape, network constant (a, b and c), bond length (C–C, C–H, C–O, C–S, C–Br and O–H), phase transition temperatures, and the total energy (Etot) on a base cell. Our finding shows that the increase of layer thickness (h) of C13H8OS–H has a negligible effect on the transition temperature, while the energy bandgap (Eg) increases from 1.646 eV to 1.675 eV. The calculation of bond length with different side chain groups was carried out for which C13H8OS–H has C–H = 1.09 Å; C13H8OS–Br has C–Br = 1.93 Å; C13H8OS–OH has C–O = 1.36 Å, O–H = 0.78 Å; C13H8OS–OCH3 has C–O = 1.44 Å, O–H =1.10 Å; C13H8OS–OC2H5 has C–O = 1.45 Å, C–C = 1.51Å, C–H = 1.10 Å. The transition temperature (T) for C13H8OS–H was 500 K < T < 562 K; C13H8OS–Br was 442 K < T < 512 K; C13H8OS–OH was 487 K < T < 543 K; C13H8OS–OCH3 was 492 K < T < 558 K; and C13H8OS–OC2H5 was 492 K < T < 572 K. The energy bandgap (Eg) of Br is of Eg = 1.621 eV, the doping of side chain groups H, OH, OCH3, and OC2H5, leads to an increase of Eg from 1.621 eV to 1.646, 1.697, 1.920, and 2.04 eV, respectively.

scholarly journals Influence of Oxidation Degree of Graphene Oxide on the Shear Rheology of Poly(ethylene glycol) Suspensions

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 41 ◽  
Author(s):  
Yago Soares ◽  
Elyff Cargnin ◽  
Mônica Naccache ◽  
Ricardo Andrade
Keyword(s):  
Graphene Oxide ◽  
Rheological Behavior ◽  
Structural Characteristics ◽  
Rheological Characterization ◽  
Polymeric Liquid ◽  
Oxidation Degree ◽  
Force Microscopy ◽  
Fluid Behavior ◽  
Atomic Force ◽  
Poly Ethylene

This work studies the influence of the concentration and oxidation degree on the rheological behavior of graphene oxide (GO) nanosheets dispersed on polyethylene glycol (PEG). The rheological characterization was fulfilled in shear flow through rotational rheometry measurements, in steady, transient and oscillatory regimes. Graphene oxide was prepared by chemical exfoliation of graphite using the modified Hummers method. The morphological and structural characteristics originating from the synthesis were analyzed by X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and atomic force microscopy. It is shown that higher oxidation times increase the functional groups, which leads to a higher dispersion and exfoliation of GO sheets in the PEG. Moreover, the addition of GO in a PEG solution results in significant growth of the suspension viscosity, and a change of the fluid behavior from Newtonian to pseudoplastic. This effect is related to the concentration and oxidation level of the obtained GO particles. The results obtained aim to contribute towards the understanding of the interactions between the GO and the polymeric liquid matrix, and their influence on the suspension rheological behavior.

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