Relationship Between Spectroscopic and Structural Properties of Poly(meta/para Phenylene)

1999 ◽  
Vol 598 ◽  
Author(s):  
Cherif. Dridi ◽  
Joël. Davenas ◽  
Ahmed. Touhami ◽  
Hafedh. Ben Ouada ◽  
Hassen. Mâaref ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Quantum Confinement ◽  
Blue Shift ◽  
Film Morphology ◽  
Energy Band Gap ◽  
Paramagnetic Resonance ◽  
Force Microscopy ◽  
Atomic Force ◽  
Electron Paramagnetic ◽  
Insight Into

ABSTRACTWe have used electron paramagnetic resonance (EPR) spectroscopy for investigating the properties of spins, such as those carried by polarons which carry both spin and charge in an electrosynthesized poly (meta/para phenylene) PMPP.Indeed, the study of their mobility provides an insight into the charge transport properties of the conjugated polymer in a microscopic scale.Moreover, we report a correlation between thin film morphology, chainlength and optical gap.Particularly, we show a blue shift upon decreasing chainlength. Furthermore, we have observed a blue shift of the energy band gap with the decrease of the surface grain size deduced from atomic force microscopy (AFM) analyses. This result has been explained in terms of quantum confinement.

scholarly journals A new building block for DNA network formation by self-assembly and polymerase chain reaction

2014 ◽  
Vol 10 ◽  
pp. 1037-1046 ◽  
Author(s):  
Holger Bußkamp ◽  
Sascha Keller ◽  
Marta Robotta ◽  
Malte Drescher ◽  
Andreas Marx
Keyword(s):  
Self Assembly ◽  
Building Block ◽  
Network Formation ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Force Microscopy ◽  
Atomic Force ◽  
Polymerase Chain ◽  
Electron Paramagnetic

The predictability of DNA self-assembly is exploited in many nanotechnological approaches. Inspired by naturally existing self-assembled DNA architectures, branched DNA has been developed that allows self-assembly to predesigned architectures with dimensions on the nanometer scale. DNA is an attractive material for generation of nanostructures due to a plethora of enzymes which modify DNA with high accuracy, providing a toolbox for many different manipulations to construct nanometer scaled objects. We present a straightforward synthesis of a rigid DNA branching building block successfully used for the generation of DNA networks by self-assembly and network formation by enzymatic DNA synthesis. The Y-shaped 3-armed DNA construct, bearing 3 primer strands is accepted by Taq DNA polymerase. The enzyme uses each arm as primer strand and incorporates the branched construct into large assemblies during PCR. The networks were investigated by agarose gel electrophoresis, atomic force microscopy, dynamic light scattering, and electron paramagnetic resonance spectroscopy. The findings indicate that rather rigid DNA networks were formed. This presents a new bottom-up approach for DNA material formation and might find applications like in the generation of functional hydrogels.

scholarly journals Dental calculus: Nano-characterization

2012 ◽  
Vol 59 (3) ◽  
pp. 154-159
Author(s):  
Djurica Grga ◽  
Marina Marjanovic ◽  
Igor Hut ◽  
Bojan Dzeletovic ◽  
Djuro Koruga
Keyword(s):  
Magnetic Field Gradient ◽  
Dental Calculus ◽  
Oral Diseases ◽  
Force Microscopy ◽  
Atomic Force ◽  
Light Matter Interaction ◽  
The Magnetic Field ◽  
Very High ◽  
Insight Into

Emerging technologies and new nanoscale information have potential to transform dental practice by improving all aspects of diagnostics and therapy. Nanocharacterization allows understanding of oral diseases at molecular and cellular levels which eventually can increase the success of prevention and treatment. Opto-magnetic spectroscopy (OMS) is a promising new technique based on light-matter interaction which allows insight into the quantum state of matter. Since biomolecules and tissues are usually paramagnetic or diamagnetic materials it is possible to determine the dynamics of para-and diamagnetism at different teeth structures using that method. The topography of the surface of a sample can be obtained with a very high resolution using atomic force microscopy (AFM), which allows observation of minimal changes up to 10 nm, while magnetic force microscopy (MFM) is used to record the magnetic field gradient and its distribution over the surface of a sample. The aim of this study was to determine the possibility of AFM and MFM for the characterization of dental calculus, and a potential application of OMS for the detection of subgingival dental calculus.

Growth and Investigation of GaN/AlN Quantum Dots

2000 ◽  
Vol 639 ◽  
Author(s):  
Hadis Morkoç ◽  
Michael A. Reshchikov ◽  
Keith M. Jones ◽  
Feng Yun ◽  
Paolo Visconti ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Blue Shift ◽  
Microscopy Study ◽  
High Quantum Efficiency ◽  
Force Microscopy ◽  
Quantum Size ◽  
Atomic Force ◽  
Layer Structures ◽  
Bulk Gan ◽  
Very High

ABSTRACTWe have fabricated GaN quantum dots (QDs) in AlN confined layer structures by molecular beam epitaxy. The size distribution and density of the QDs have been estimated from an atomic force microscopy study. Very high quantum efficiency of photoluminescence (PL) has been obtained in some samples with QDs. Compared to the GaN bulk samples, it increased by orders of magnitude. In some samples the quantum size effect dominated, resulting in the blue-shift of the QD related PL peak, whereas in the samples with larger dots a red-shift up to 0.8 eV has been observed, which is related to strong polarization effects. We have observed a blue-shift of the PL peak with excitation intensity in the samples with large dots due to screening effect. The temperature-induced quenching of PL occurs at higher temperatures compared to bulk GaN due to the confinement of nonequilibrium carriers in the QDs. An excited state has been observed in some samples.

scholarly journals Anomalous chemically induced electron spin polarization in proton-coupled electron transfer reactions: insight into radical pair dynamics

2020 ◽  
Vol 11 (24) ◽  
pp. 6268-6274
Author(s):  
Alexander M. Brugh ◽  
Malcolm D. E. Forbes
Keyword(s):  
Electron Transfer ◽  
Ruthenium Complex ◽  
Transfer Reactions ◽  
Electron Spin Polarization ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
Proton Coupled Electron Transfer ◽  
Chemically Induced ◽  
Electron Paramagnetic ◽  
Insight Into

Time-resolved electron paramagnetic resonance (TREPR) spectroscopy has been used to study the proton coupled electron transfer (PCET) reaction between a Ruthenium complex (Ru(bpz)(bpy)2) and several substituted hydroquinones (HQ).

scholarly journals Quantitative atomic force microscopy provides new insight into matrix vesicle mineralization

2019 ◽  
Vol 667 ◽  
pp. 14-21 ◽  
Author(s):  
Justin S. Plaut ◽  
Agnieszka Strzelecka-Kiliszek ◽  
Lukasz Bozycki ◽  
Slawomir Pikula ◽  
René Buchet ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Matrix Vesicle ◽  
Force Microscopy ◽  
Atomic Force ◽  
Insight Into

scholarly journals Electron Paramagnetic Resonance - A Powerful Tool of Medical Biochemistry in Discovering Mechanisms of Disease and Treatment Prospects

2010 ◽  
Vol 29 (3) ◽  
pp. 175-188 ◽  
Author(s):  
Ivan Spasojević
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Epr Spectroscopy ◽  
Human Organism ◽  
Efficient Tool ◽  
Paramagnetic Resonance ◽  
Beneficial Effects ◽  
Ascorbyl Radical ◽  
Antioxidative Therapy ◽  
Electron Paramagnetic ◽  
Insight Into

Electron Paramagnetic Resonance - A Powerful Tool of Medical Biochemistry in Discovering Mechanisms of Disease and Treatment ProspectsIn pathophysiological conditions related to oxidative stress, the application of selected antioxidants could have beneficial effects on human health. Electron paramagnetic resonance (EPR) spectroscopy is a technique that provides unique insight into the redox biochemistry, due to its ability to: (i) distinguish and quantify different reactive species, such as hydroxyl radical, superoxide, carbon centered radicals, hydrogen atom, nitric oxide, ascorbyl radical, melanin, and others; (ii) evaluate the antioxidative capacity of various compounds, extracts and foods; (iii) provide information on other important parameters of biological systems. A combination of EPR spectroscopy and traditional biochemical methods represents an efficient tool in the studies of disease mechanisms and antioxidative therapy prospects, providing a more complete view into the redox processes in the human organism.

Sign in / Sign up

Export Citation Format

Share Document