l-Tartaric acid assisted binary organogel system: strongly enhanced fluorescence induced by supramolecular assembly

2005 ◽  
Vol 3 (14) ◽  
pp. 2508 ◽  
Author(s):  
Chunyan Bao ◽  
Ran Lu ◽  
Ming Jin ◽  
Pengchong Xue ◽  
Changhui Tan ◽  
...  
Keyword(s):  
Tartaric Acid ◽  
Supramolecular Assembly ◽  
Enhanced Fluorescence

The 3-Dimensional Molecular Structure of the Actin Filament Revisited

1985 ◽  
Vol 43 ◽  
pp. 480-481
Author(s):  
U. Aebi ◽  
R. Millonig ◽  
H. Salvo
Keyword(s):  
Actin Filament ◽  
Supramolecular Assembly ◽  
Specimen Preparation ◽  
X Ray Diffraction ◽  
Single Filament ◽  
X Ray ◽  
3 Dimensional ◽  
Filament Diameter ◽  
Preparation Conditions ◽  
Apparent Diameter

To date, most 3-D reconstructions of undecorated actin filaments have been obtained from actin filament paracrystal data (for refs, see 1,2). However, due to the fact that (a) the paracrystals may be several filament layers thick, and (b) adjacent filaments may sustantially interdigitate, these reconstructions may be subject to significant artifacts. None of these reconstructions has permitted unambiguous tracing or orientation of the actin subunits within the filament. Furthermore, measured values for the maximal filament diameter both determined by EM and by X-ray diffraction analysis, vary between 6 and 10 nm. Obviously, the apparent diameter of the actin filament revealed in the EM will critically depend on specimen preparation, since it is a rather flexible supramolecular assembly which can easily be bent or distorted. To resolve some of these ambiguities, we have explored specimen preparation conditions which may preserve single filaments sufficiently straight and helically ordered to be suitable for single filament 3-D reconstructions, possibly revealing molecular detail.

Supramolecular Assembly of U(IV) Clusters and Superatoms

2020 ◽  
Author(s):  
Ian Colliard ◽  
Gregory Morrosin ◽  
Hans-Conrad zur Loye ◽  
May Nyman
Keyword(s):  
Quantum Dots ◽  
Supramolecular Assembly ◽  
Emergent Properties ◽  
Organic Media ◽  
Body Centered Cubic ◽  
Cluster Anions ◽  
Charge Balance ◽  
Interpenetrating Networks ◽  
Hierarchical Assembly ◽  
Two Parameters

Superatoms are nanometer-sized molecules or particles that can form ordered lattices, mimicking their atomic counterparts. Hierarchical assembly of superatoms gives rise to emergent properties in superlattices of quantum-dots, p-block clusters, and fullerenes. Here, we introduce a family of uranium-oxysulfate cluster anions whose hierarchical assembly in water is controlled by two parameters; acidity and the countercation. In acid, larger Ln<sup>III</sup> (Ln=La-Ho) link hexamer (U<sub>6</sub>) oxoclusters into body-centered cubic frameworks, while smaller Ln<sup>III</sup> (Ln=Er-Lu &Y) promote linking of fourteen U<sub>6</sub>-clusters into hollow superclusters (U<sub>84</sub> superatoms). U<sub>84</sub> assembles into superlattices including cubic-closest packed, body-centered cubic, and interpenetrating networks, bridged by interstitial countercations, and U<sub>6</sub>-clusters. Divalent transition metals (TM=Mn<sup>II </sup>and Zn<sup>II</sup>), with no added acid, charge-balance and promote the fusion of 10 U<sub>6</sub> and 10 U-monomers into a wheel–shaped cluster (U<sub>70</sub>). Dissolution of U<sub>70</sub> in organic media reveals (by small-angle Xray scattering) that differing supramolecular assemblies are accessed, controlled by TM-linking of U<sub>70</sub>-clusters. <br>

Enhanced-Fluorescence of a Dye on DNA- assembled Gold Nano-Dimers Discriminated by Lifetime Correlation Spectroscopy

2017 ◽  
Author(s):  
Pedro M. R. Paulo ◽  
David Botequim ◽  
Agnieszka Jóskowiak ◽  
Sofia Martins ◽  
Duarte M. F. Prazeres ◽  
...  
Keyword(s):  
Single Molecule ◽  
Fluorescence Emission ◽  
Directed Assembly ◽  
Plasmon Mode ◽  
Correlation Spectroscopy ◽  
Enhanced Fluorescence ◽  
Detection Volume ◽  
Relaxation Component ◽  
Good Agreement ◽  
Confocal Detection

<div> <div> <div> <p>We have employed DNA-directed assembly to prepare dimers of gold nanoparticles and used their longitudinally coupled plasmon mode to enhance the fluorescence emission of an organic red-emitting dye, Atto-655. The plasmon- enhanced fluorescence of this dye using dimers of 80 nm particles was measured at single molecule detection level. The top enhancement factors were above 1000-fold in 71% of the dimers within a total of 32 dimers measured, and, in some cases, they reached almost 4000-fold, in good agreement with model simulations. Additionally, fluorescence lifetime correlation analysis enabled the separation of enhanced from non-enhanced emission simultaneously collected in our confocal detection volume. This approach allowed us to recover a short relaxation component exclusive to enhanced emission that is attributed to the interaction of the dye with DNA in the interparticle gaps. </p> </div> </div> </div>

ANTIPHYTOPATHOGENIC EFFECT OF TARTARIC ACID SYNTHETIC DERIVATIVES

2020 ◽  
pp. 3-6
Author(s):  
B. G. Babayan ◽  
S. A. Bagdasaryan ◽  
M. A. Melkumyan ◽  
A. R. Mikaelyan
Keyword(s):  
Tartaric Acid ◽  
Synthetic Derivatives

Enzymatic Iodination of Maleic and Fumaric Acids Diethyl Esters

2009 ◽  
Vol 59 (12) ◽  
pp. 1400-1404
Author(s):  
Marius Tudorascu ◽  
Spiridon Oprea ◽  
Afrodita Doina Marculescu ◽  
Stefania Tudorascu
Keyword(s):  
Hydrogen Peroxide ◽  
Tartaric Acid ◽  
Disperse System ◽  
Hydrogen Peroxide Solution ◽  
Ultrasonic Pretreatment ◽  
Tartaric Acids ◽  
Inactive Form ◽  
Generating System ◽  
Sole Product

The mechanism of the enzymatic iodination process of diethylmaleate and diethylfumarate (which present no miscibility with water) in the presence of lactoperoxidase, both in diluted hydrogen peroxide solution and in a generating system of hydrogen peroxide using ammonium and calcium iodides as halide sources in disperse system (after an ultrasonic pretreatment) was studied. The obtained sole product (diethyl-2, 3-diiodosuccinate) after the enzymatic iodination process was directly hydrolyzed to a tartaric acid present in an optically inactive form. The mechanism of obtaining the intermediate and final products and respectively, the existence of both D, L-tartaric acid and meso-tartaric acids (as lithium bitartrates) were also investigated.

Synthesis and Kinetics of Highly Substituted Piperidines in the Presence of Tartaric Acid as a Catalyst

2018 ◽  
Vol 21 (4) ◽  
pp. 302-311
Author(s):  
Younes Ghalandarzehi ◽  
Mehdi Shahraki ◽  
Sayyed M. Habibi-Khorassani
Keyword(s):  
Ambient Temperature ◽  
Tartaric Acid ◽  
Aromatic Aldehydes ◽  
One Pot ◽  
Rate Determining Step ◽  
State Approximation ◽  
Solvent Free Conditions ◽  
Steady State Approximation ◽  
Absorbance Changes ◽  
The One

Aim & Scope: The synthesis of highly substituted piperidine from the one-pot reaction between aromatic aldehydes, anilines and β-ketoesters in the presence of tartaric acid as a catalyst has been investigated in both methanol and ethanol media at ambient temperature. Different conditions of temperature and solvent were employed for calculating the thermodynamic parameters and obtaining an experimental approach to the kinetics and mechanism. Experiments were carried out under different temperature and solvent conditions. Material and Methods: Products were characterized by comparison of physical data with authentic samples and spectroscopic data (IR and NMR). Rate constants are presented as an average of several kinetic runs (at least 6-10) and are reproducible within ± 3%. The overall rate of reaction is followed by monitoring the absorbance changes of the products versus time on a Varian (Model Cary Bio- 300) UV-vis spectrophotometer with a 10 mm light-path cell. Results: The best result was achieved in the presence of 0.075 g (0.1 M) of catalyst and 5 mL methanol at ambient temperature. When the reaction was carried out under solvent-free conditions, the product was obtained in a moderate yield (25%). Methanol was optimized as a desirable solvent in the synthesis of piperidine, nevertheless, ethanol in a kinetic investigation had none effect on the enhancement of the reaction rate than methanol. Based on the spectral data, the overall order of the reaction followed the second order kinetics. The results showed that the first step of the reaction mechanism is a rate determining step. Conclusion: The use of tartaric acid has many advantages such as mild reaction conditions, simple and readily available precursors and inexpensive catalyst. The proposed mechanism was confirmed by experimental results and a steady state approximation.

BSA Au Clusters as a Probe for Enhanced Fluorescence Detection Using Multipulse Excitation Scheme

2014 ◽  
Vol 14 (13) ◽  
pp. 1139-1144 ◽  
Author(s):  
Sangram Raut ◽  
Ryan Rich ◽  
Rafal Fudala ◽  
R. Kokate ◽  
J.D. Kimball ◽  
...  
Keyword(s):  
Fluorescence Detection ◽  
Enhanced Fluorescence ◽  
Excitation Scheme ◽  
Au Clusters

Influence of substrate on modified oscillation reactions of the Belousov-Zhabotinskii type

1983 ◽  
Vol 48 (11) ◽  
pp. 3223-3228 ◽  
Author(s):  
Peter Ševčík ◽  
Ľubica Adamčíková
Keyword(s):  
Oxalic Acid ◽  
Kinetic Parameters ◽  
Tartaric Acid ◽  
Bz Reaction ◽  
Oscillation Cycle ◽  
Influence Of Substrate

The kinetic parameters of the reaction steps of the oscillation cycle and the parameters of modified oscillation reactions of the Belousov-Zhabotinskii (BZ) type with oxalic acid, tartaric acid, and hypophosphite ions were compared with predictions of Edelson's analysis based on the mechanism of the classical BZ reaction.

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