scholarly journals Physical, Thermal and Biological Properties of Yellow Dyes with Two Azodiphenylether Groups of Anthracene

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5757
Author(s):  
Carla Alice Carabet ◽  
Anca Moanță ◽  
Ion Pălărie ◽  
Gabriela Iacobescu ◽  
Andrei Rotaru ◽  
...  
Keyword(s):  
Chemical Elements ◽  
Energy Levels ◽  
Polarized Light ◽  
Biological Properties ◽  
Laser Fluorescence ◽  
Azo Compounds ◽  
Double Refraction ◽  
Good Thermal Stability ◽  
Optical Phenomenon ◽  
Glass Surfaces

Two yellow bis-azo dyes containing anthracene and two azodiphenylether groups (BPA and BTA) were prepared, and an extensive investigation of their physical, thermal and biological properties was carried out. The chemical structure was confirmed by the FTIR spectra, while from the UV–Vis spectra, the quantum efficiency of the laser fluorescence at the 476.5 nm was determined to be 0.33 (BPA) and 0.50 (BTA). The possible transitions between the energy levels of the electrons of the chemical elements were established, identifying the energies and the electronic configurations of the levels of transition. Both crystals are anisotropic, the optical phenomenon of double refraction of polarized light (birefringence) taking place. Images of maximum illumination and extinction were recorded when the crystals of the bis-azo compounds rotated by 90° each, which confirms their birefringence. A morphologic study of the thin films deposited onto glass surfaces was performed, proving the good adhesion of both dyes. By thermal analysis and calorimetry, the melting temperatures were determined (~224–225 °C for both of them), as well as their decomposition pathways and thermal effects (enthalpy variations during undergoing processes); thus, good thermal stability was exhibited. The interaction of the two compounds with collagen in the suede was studied, as well as their antioxidant activity, advocating for good chemical stability and potential to be safely used as coloring agents in the food industry.

scholarly journals IV. On double refraction in a viscous fluid in motion

1874 ◽  
Vol 22 (148-155) ◽  
pp. 46-47 ◽  
Keyword(s):  
Internal Friction ◽  
Viscous Fluid ◽  
Polarized Light ◽  
Elastic Solid ◽  
The State ◽  
Solid Cylinder ◽  
Annular Space ◽  
Double Refraction ◽  
Fresh Start ◽  
The Moment

According to Poisson’s theory of the internal friction of fluids, a viscous fluid behaves as an elastic solid would do if it were periodically liquefied for an instant and solidified again, so that at each fresh start it becomes for the moment like an elastic solid free from strain. The state of strain of certain transparent bodies may be investigated by means of their action on polarized light. This action was observed by Brewster, and was shown by Fresnel to be an instance of double refraction. In 1866 I made some attempts to ascertain whether the state of strain in a viscous fluid in motion could be detected by its action on polarized light. I had a cylindrical box with a glass bottom. Within this box a solid cylinder could be made to rotate. The fluid to be examined was placed in the annular space between this cylinder and the sides of the box. Polarized light was thrown up through the fluid parallel to the axis, and the inner cylinder was then made to rotate. I was unable to obtain any result with solution of gum or sirup of sugar, though I observed an effect on polarized light when I compressed some Canada balsam which had become very thick and almost solid in a bottle.

scholarly journals Dye-enhanced laser fluorescence detection on natural caries lesions in primary teeth

2015 ◽  
Vol 21 (3) ◽  
pp. 145
Author(s):  
Fausto Medeiros Mendes ◽  
Victor Moreira Leamari ◽  
Márcia Turolla Wanderley ◽  
Mariana Minatel Braga ◽  
Juliana Mattos-Silveira ◽  
...  
Keyword(s):  
Primary Teeth ◽  
Fluorescent Dyes ◽  
Protoporphyrin Ix ◽  
Polarized Light ◽  
Laser Fluorescence ◽  
Primary Molars ◽  
Smooth Surfaces ◽  
Occlusal Caries ◽  
Occlusal Surfaces ◽  
Caries Lesions

Objective: This study aimed to investigate the association of two fluorescent dyes and Laser Fluorescence (LF) device in detecting smooth and occlusal natural caries in primary teeth in vitro.Methods: Measurements were performed with the LF and with LF associated with tetrakis (N-methylpyridyl)porphyrin (LF TMPyP) and protoporphyrin IX (LF PPIX) in 72 smooth (63 primary molars) and 134 occlusal sites (81 primary molars). For validation, surfaces were sectioned and sections obtained were evaluated under stereomicroscope. Smooth surfaces were also evaluated using polarized light microscopy and Knoop microhardness. For both smooth and occlusal surfaces, ROC analyses were performed, and sensitivities, specificities and accuracies were assessed. In smooth surfaces, Pearson’s correlation coefficients between LF values and lesions hardness or lesions depth were calculated.Results: LF TMPyP presented higher correlation with hardness and lesion depth than other methods in smooth surfaces. No differences were observed in other parameters among the methods, in both smooth and occlusal surfaces.Relevance: The LF TMPyP might improve performance in quantifying smooth-surface caries lesions in primary teeth. However, the sensitivity is improved at D2 (caries extending into inner half of the enamel but not to amelodentinal junction) threshold when using PPIX in smooth caries lesions. The association of LF with fluorescent dyes does not improve the performance on occlusal caries.

scholarly journals Performance of Laser Fluorescence for Residual Caries Detection in Primary Teeth

2008 ◽  
Vol 02 (03) ◽  
pp. 176-184 ◽  
Author(s):  
Taskin Gurbuz ◽  
Yucel Yilmaz ◽  
Fatih Sengul
Keyword(s):  
Light Microscopy ◽  
Gold Standard ◽  
Primary Teeth ◽  
Polarized Light ◽  
Laser Fluorescence ◽  
Caries Detection ◽  
Sem Images ◽  
Significant Difference ◽  
Residual Caries ◽  
Cavity Floor

ABSTRACTObjectives: The aim of this study was to evaluate the performance of a visual-tactile examination and a laser fluorescence device for detecting residual dentinal caries after carious dentin removal with bur excavation, hand excavation and chemomechanical excavation (Carisolv™].Methods: Thirty extracted coronal caries primary second molars were used. The caries infected dentin has been removed. A blinded examiner checked all cavities for residual caries using a visualtactile examination and laser fluorescence. Then the teeth were sectioned through the prepared cavities andthe two halves of each tooth were processed for light microscopy and Scanning Electron Microscopy (SEM). The presence or absence of residual caries was verified using polarized light microscopy as the gold standard. The cavity floor dentin after removing carious dentin was examined using SEM.Results: In among all groups a significant difference is determined between visual-tactile examination and laser fluorescence (P<.05). There was an agreement between laser fluorescence or visual-tactile examination and histological gold standard (P>.05). In addition, SEM images of the surfaces with the caries removed have shown that a vast majority of the tubule openings is observed to be open in the samples of the Carisolv group in opposition to the other groups.Conclusions: The laser fluorescence system could be effective in checking the removal by other methods, such as bur or Carisolv and avoid excessive removal of the sound dentin. (Eur J Dent 2008;2:176-184)

scholarly journals MECHANOCHEMICAL ACTIVATION OF PHARMACEUTICAL SUBSTANCES AS A FACTOR FOR MODIFICATION OF THEIR PHYSICAL, CHEMICAL AND BIOLOGICAL PROPERTIES

2019 ◽  
pp. 118-123 ◽  
Author(s):  
A.V. SYROESHKIN ◽  
E.V. USPENSKAYA ◽  
T.V. PLETENEVA ◽  
M.A. MOROZOVA ◽  
T.V. MAKSIMOVA ◽  
...  
Keyword(s):  
Biological Activity ◽  
Chemical Elements ◽  
Raw Materials ◽  
Biological Activities ◽  
Biological Properties ◽  
Raw Material ◽  
Native Form ◽  
Preparation Methods ◽  
Pharmaceutical Substances ◽  
Before And After

Objective: Study the influence of the mechanical preparation methods (grinding, fluidization) of solid pharmaceutical substances (PS) and herbal raw material on their physicochemical properties and biological activities. Methods: Test substances and solvents-Lactose monohydrate (DFE Pharma, Germany). Sodium chloride, bendazol hydrochloride (all Sigma-Aldrich, USA) and herbal raw material (Callisia fragrans). The dispersity and native structure of pharmaceutical substances were analyzed by several methods: optical microscopy–Altami BIO 2 microscope (Russia); low angle laser light scattering (LALLS) method (Malvern Instruments, UK); Spirotox method–Quasichemical kinetic of cell transition of cellular biosensor Spirostomum ambiguum; Fourier-transform infrared spectroscopy–the analysis in the middle IR region was carried out using an IR Cary 630 Fourier spectrometer (Agilent Technologies, USA). The analysis of dried leaves of C. fragrans before and after mechanical activation was performed using Shimadzu EDX-7000 X-ray fluorescence spectrophotometer without mineralization (Shimadzu, Japan). Results: It was established that the mechanical change, such as dispersion and drying, alters the biological activity of PS and herbal raw materials. The observed increase in the influence of the dispersed substance on the biosensor S. ambiguum is quantitatively estimated from the values of the activation energy (obsEa), which turns to be valued 1,5 (P≤0,05) times more than for the native form substance. In the study of the dependence of the availability of chemical elements K, Ca, Zn on the degree of dispersion of herbal raw materials was established a quantitative 4-fold (P≤0,05) increase in the concentration of elements in mechano-activated raw materials. Conclusion: By the example of the biological model of Spirotox (single-celled biosensor S. ambiguum) and herbal raw materials obtained from C. fragrans, the increase of biological activity of PS at the dispersion of initial preparations was proved.

scholarly journals Stable P3HT: amorphous non-fullerene solar cells with a high open-circuit voltage of 1 V and efficiency of 4%

RSC Advances ◽  
2019 ◽  
Vol 9 (36) ◽  
pp. 20733-20741 ◽  
Author(s):  
HyunKyung Lee ◽  
Sora Oh ◽  
Chang Eun Song ◽  
Hang Ken Lee ◽  
Sang Kyu Lee ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Solar Cells ◽  
Organic Solar Cells ◽  
High Efficiency ◽  
Open Circuit Voltage ◽  
Energy Levels ◽  
Open Circuit ◽  
Good Thermal Stability

A 3D-shaped SF-HR was designed and synthesized for use in non-fullerene organic solar cells. Owing to the aligned energy levels, the P3HT:SF-HR system exhibited a high efficiency of 4.01% with good thermal stability and photostability.

scholarly journals On the laws which regulate the absorption of polarized light by doubly refracting crystals. By David Brewster, LL. D. F. R. S. Lond. and Edinb. In a letter addressed to the Right Hon. Sir Joseph Banks, Bart. G. C. B. P. R. S

1833 ◽  
Vol 2 ◽  
pp. 104-105
Keyword(s):  
Polarized Light ◽  
The Other ◽  
Double Refraction ◽  
Pink Colour ◽  
The One ◽  
The Right ◽  
Number Of Particles

In examining the polarizing structure of acetate of copper, the author’s attention was drawn to certain changes of colour exhibited by its crystal, when exposed in different positions to polarized light; and as these were independent of the thickness of the plate, and of any analysis of the transmitted pencil, he was induced to regard them as a new affection of light, ascribable to the absorption of the homogeneous tints forming the compound colour of the crystal. Dr. Brewster, therefore, collected a variety of coloured crystals, with a view to examine the phenomena which they presented, when cut at different angles with the axis, and when exposed in different positions to polarized light. The details of this examination are next given; and as the property of transparent bodies, by which they detain and assimilate to their own substance a portion of the rays which penetrate them while the rest are freely transmitted, is related to the axes of double refraction, the author first describes the phenomena presented by crystals of one axis, and then explains the modifications which they undergo when the number of axes is increased. It appears from these investigations that the colouring particles of crystals, instead of being indiscriminately dispersed throughout their mass, have an arrangement related to the ordinary and extraordinary forces which they exert upon light. In some cases, the extraordinary medium appeared to be tinged with the same kind and number of colouring particles as the ordinary medium; but in other cases, in the same mineral, the extraordinary medium was either tinged with a different number of particles of the same colour, or with a colouring matter entirely different from that of the ordinary medium. In some specimens of topaz the colouring matter of the one medium was more easily discharged by heat than that of the other, one of the pencils being yellow and the other pink : hence it is a mistake to suppose that in converting yellow topazes into pink by heat, the former colour is changed into the latter; the fact being, that the yellow is discharged by heat, thus leaving the pink unimpaired. Hence it may be ascertained beforehand whether a topaz will receive a pink colour by heat; for if that colour exist in one of its images, seen by exposing it to a polarized ray, we may predict the success of the experiment.

scholarly journals Fluorescent Indolo[2,3-b]quinoxalin-2-yl)(Phenyl)methanone Dyes: Photophysical, Aie Activity, Electrochemical, and Theoretical Studies

2021 ◽  
Author(s):  
Deepali Kanekar ◽  
Sudhakar Dhanawade ◽  
Anand Jadhav ◽  
Mohmmed Ghadiyali ◽  
Sajeev Chacko ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Energy Levels ◽  
Potential Candidate ◽  
Good Thermal Stability ◽  
Td Dft ◽  
Solid Film ◽  
Donor Acceptor ◽  
Homo And Lumo ◽  
Photophysical Studies ◽  
Homo And Lumo Energy

Abstract Herein, we have synthesized four indolo[2,3-b]quinoxalin-2-yl)(phenyl)methanone derivatives 1−4 by cyclocondensation. The photophysical studies of dyes in various solvents and neat solid film exhibit typical electronic spectra with inbuilt intramolecular charge transfer (ICT) (λmax: 397‒490 nm) confirming donor-acceptor architecture. Herein, dyes fluoresce in the blue-orange region (λEmax: 435–614) on excitation at their ICT maxima in toluene, ethyl acetate, chloroform, DMSO, and neat solid film. 1 and 2 which exhibit good emission intensity in all mediums, were studied for aggregation-induced emission (AIE) effect. Electrochemical studies indicate 1−4 possess relatively low lying LUMO (‒3.65 to ‒3.98 eV) comparable to reported n-type/electron-transporting materials. The HOMO and LUMO energy levels in 1−4 were evaluated by DFT and TD-DFT calculations. TGA analysis shows 1−4 exhibit good thermal stability. The characteristic optoelectronic properties and thermal stability signify these dyes are potential candidate for their application in optoelectronics.

scholarly journals Investigation of the Thermally Generated Au and Ag Nanoislands for SERS and LSPR Applications

2021 ◽  
Vol 6 (1) ◽  
pp. 32
Author(s):  
Istvan Csarnovics ◽  
Miklos Veres ◽  
Attila Bonyár ◽  
Petra Pál
Keyword(s):  
Metallic Nanoparticles ◽  
Hungarian Academy ◽  
Thin Layers ◽  
Process Time ◽  
Gold And Silver Nanoparticles ◽  
Optical Phenomenon ◽  
Sensor Applications ◽  
Research Scholarship ◽  
Glass Surfaces ◽  
Academy Of Sciences

Gold and silver nanoparticles are widely used as signal amplification elements in various electrochemical and optical sensor applications. Although these NPs can be synthesized in several ways, perhaps one of the simplest methods of their preparation is the thermal annealing of pre-deposited thin metal films on glass. With this method, the parameters of the annealing process (time and temperature) and the pre-deposited thin film thickness influence and define the resulting size and distribution of the NPs on the surface. LSPR is a very sensitive optical phenomenon and can be utilized for a large variety of sensing purposes. SERS is an analytical method that can significantly increase the yield of the Raman scattering of target molecules adsorbed on the surface of metallic nanoparticles. In this work, the performance of Au/Ag nanoislands was investigated for SERS and LSPR applications. The nanoislands were generated by thermally annealing thin layers of silver and gold, which were previously sputtered onto glass surfaces. The sensitivity of LSPR and SERS-based devices were strongly dependent on the used material and the size and geometry of the metallic nanoparticles. By controlling these parameters, the plasmon absorption band can be tuned and the sensitivity can be optimized. This work was supported by the GINOP-2.3.2-15-2016-00041 project. ICs is grateful for the support of the János Bólyai Research Scholarship of the Hungarian Academy of Sciences.

THE SPACE-GROUP OF POTASSIUM DITHIONATE

1931 ◽  
Vol 4 (6) ◽  
pp. 565-569 ◽  
Author(s):  
W. H. Barnes ◽  
G. V. Helwig
Keyword(s):  
Polarized Light ◽  
Rotatory Power ◽  
Quarter Wave Plate ◽  
Double Refraction ◽  
Space Group ◽  
X Ray ◽  
Single Cross ◽  
Quarter Wave ◽  
Crystal Class ◽  
Axis Rotation

An X-ray investigation of the space-group of potassium dithionate is described.Approximate measurements of refractive indices and specific rotatory power were in harmony with those obtained by Groth. From Laue photographs and the fact of optical activity, the crystal class is trigonal trapezohedral, in agreement with crystallographic data.The crystals showed the single cross and circular concentric rings characteristic of uniaxial crystals when plates perpendicular to the c axis were examined under crossed Niçois in convergent polarized light. The sign of the double refraction as determined with a quarter-wave plate was positive.The primitive translations of the unit cell, determined from the a axis and c axis rotation photographs were: a0, 9.77 Å; c0, 6.28 Å, and a:c = 1:0.644. The number of molecular units per cell was found to be three. It is deduced that the lattice must be hexagonal (Γh.) From the fact that no abnormal spacings of {0001} were observed, the space-group of potassium dithionate is shown to be either [Formula: see text] or [Formula: see text].

scholarly journals On the action of crystallized bodies on homogeneous light, and on the causes of the deviation from Newton’s scale in the tints which many of them develope on exposure to a polarized ray

1833 ◽  
Vol 2 ◽  
pp. 122-123
Keyword(s):  
Polarized Light ◽  
The Other ◽  
Angular Deviation ◽  
Biot’S Theory ◽  
Double Refraction ◽  
Biot's Theory ◽  
The Law ◽  
The One ◽  
Polarization Of Light

When Malus published his discovery of the polarization of light the list of doubly-refracting crystals was small; and as the most remarkable of them possessed only one axis of double refraction, it Was presumed that the law discovered by Huyghens, applicable to that one, might hold good in all; but the discovery of crystals with two axes of double refraction has proved the fallacy of such generalization, and rendered new and extensive investigations necessary. There are two modes of conducting observations on double refraction and polarization; the one turns upon immediate observation of the angular deviation of the extraordinary pencil, the other depends upon the separation of a polarized ray into complementary portions by the action of a crystallized lamina. After noticing the advantages of the latter, Mr. H. observes, that to render observations on the tints developed by polarized light available, they must be comparable to each other; hence the importance of discovering the existence and tracing the laws of those causes which operate to disturb their regularity. In the author’s first inquiries on the polarization of light, he was Struck by the great deviation from the succession of colours in their laminæ, as observed by Newton, which many crystals exhibit when cut into plates perpendicular to one of their axes; and finding this phenomenon unconnected with irregularities in their thickness or polish, and uniformly repeated in different and perfect specimens, he was led to inquire into their causes, especially as they appeared to form an unanswerable objection to M. Biot’s theory, which perfectly explains the tints in crystals with one axis.

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