scholarly journals Silicon Phthalocyanines: Synthesis and resurgent applications

2021 ◽  
Author(s):  
Koushambi Mitra ◽  
Matthew C. T. Hartman
Keyword(s):  
Absorption And Emission ◽  
Silicon Phthalocyanines ◽  
Porphyrin Analogues

The intense far-red absorption and emission features have made silicon phthalocyanines (SiPcs) distinct from the structurally related porphyrin analogues. Unlike most other phthacyanines, SiPcs possess two additional axial bonds which...

Some Results of the Spectroscopic Study of Four Close Binary Systems of Early Spectral Types

1965 ◽  
Vol 5 ◽  
pp. 120-130
Author(s):  
T. S. Galkina
Keyword(s):  
Spectroscopic Study ◽  
Spectral Type ◽  
Spectroscopic Investigation ◽  
Binary Systems ◽  
Quantitative Information ◽  
Close Binary ◽  
Physical Parameters ◽  
Absorption And Emission ◽  
Close Binary Systems ◽  
Quantitative Estimates

It is necessary to have quantitative estimates of the intensity of lines (both absorption and emission) to obtain the physical parameters of the atmosphere of components.Some years ago at the Crimean observatory we began the spectroscopic investigation of close binary systems of the early spectral type with components WR, Of, O, B to try and obtain more quantitative information from the study of the spectra of the components.

Polarimetric Observations of Red Variables: A Study of Gas and Particle Interactions

1979 ◽  
Vol 46 ◽  
pp. 386-408 ◽  
Author(s):  
G. V. Coyne ◽  
I. S. McLean
Keyword(s):  
Wavelength Dependence ◽  
Stellar Atmosphere ◽  
Molecular Absorption ◽  
Absorption Bands ◽  
Absorption And Emission ◽  
Mira Variables ◽  
Stellar Photosphere ◽  
Regular Variable ◽  
Red Supergiants ◽  
Balmer Lines

AbstractIn recent years the wavelength, dependence of the polarization in a number of Mira variables, semi-regular variables and red supergiants has been measured with resolutions between 0.3 and 300 A over the range 3300 to 11000 A. Variations are seen across molecular absorption bands, especially TiO bands, and across atomic absorption and emission lines, especially the Balmer lines. In most cases one can ignore or it is possible to eliminate the effects due to interstellar polarization, so that one can study the polarization mechanisms operating in the stellar atmosphere and environment. The stars Omicron Ceti. (Mira), V CVn (semi-regular variable) and Mu Cephei (M2 la), in addition to other stars similar to them, will be discussed in some detail.Models to explain the observed polarization consider that the continuum flux is polarized either by electron, molecular and/or grain scattering or by temperature variations and/or geometrical asymmetries over the stellar photosphere. This polarized radiation is affected by atomic and molecular absorption and emission processes at various geometric depths in the stellar atmosphere and envelope. High resolution spectropolarimetry promises, therefore, to be a power-rul tool for studying stratification effects in these stars.

Utilizing ICG Spectroscopical Properties for Real-Time Nanoparticle Release Quantification In vitro and In vivo in Imaging Setups

2020 ◽  
Vol 26 (31) ◽  
pp. 3828-3833 ◽  
Author(s):  
Tuula Peñate-Medina ◽  
Eike Kraas ◽  
Kunliang Luo ◽  
Jana Humbert ◽  
Hanwen Zhu ◽  
...  
Keyword(s):  
Release Kinetics ◽  
Pure Water ◽  
Squamous Carcinoma ◽  
Peak Shift ◽  
Intensity Increase ◽  
Nude Mouse Model ◽  
Absorption And Emission ◽  
Squamous Carcinoma Cells

Background: Nanoparticle imaging and tracking the release of the loaded material from the nanoparticle system have attracted significant attention in recent years. If the release of the loaded molecules could be monitored reliably in vivo, it would speed up the development of drug delivery systems remarkably. Methods: Here, we test a system that uses indocyanine green (ICG) as a fluorescent agent for studying release kinetics in vitro and in vivo from the lipid iron nanoparticle delivery system. The ICG spectral properties like its concentration dependence, sensitivity and the fluctuation of the absorption and emission wavelengths can be utilized for gathering information about the change of the ICG surrounding. Results: We have found that the absorption, fluorescence, and photoacoustic spectra of ICG in lipid iron nanoparticles differ from the spectra of ICG in pure water and plasma. We followed the ICG containing liposomal nanoparticle uptake into squamous carcinoma cells (SCC) by fluorescence microscopy and the in vivo uptake into SCC tumors in an orthotopic xenograft nude mouse model under a surgical microscope. Conclusion: Absorption and emission properties of ICG in the different solvent environment, like in plasma and human serum albumin, differ from those in aqueous solution. Photoacoustic spectral imaging confirmed a peak shift towards longer wavelengths and an intensity increase of ICG when bound to the lipids. The SCC cells showed that the ICG containing liposomes bind to the cell surface but are not internalized in the SCC-9 cells after 60 minutes of incubation. We also showed here that ICG containing liposomal nanoparticles can be traced under a surgical camera in vivo in orthotopic SCC xenografts in mice.

A Brief Introduction to Porphyrin Compounds Used in Tumor Imaging and Therapies

2020 ◽  
Vol 20 ◽  
Author(s):  
Lili Pan ◽  
Yu Ma ◽  
Xiaoai Wu ◽  
Huawei Cai ◽  
Feng Qin ◽  
...  
Keyword(s):  
Tumor Imaging ◽  
Photoacoustic Imaging ◽  
Therapeutic Agents ◽  
Biochemical Properties ◽  
Therapeutic Effects ◽  
Future Prospects ◽  
Animal Tissues ◽  
Sonodynamic Therapy ◽  
Porphyrin Derivatives ◽  
Porphyrin Analogues

Abstract:: As a group of heterocyclic macrocycle organic natural compounds occurring universally in animal tissues and plants, porphyrins are composed of four modified pyrrole subunits. Porphyrin analogues/derivatives possess multiple biochemical properties because of their unique structures and have been extensively investigated in cancer treatment. Studies have shown that porphyrins and their derivatives have the ability to locate in tumor cells in a variety of human cancers, and these compounds not only exhibit potent therapeutic effects as photodynamic agents but also show promising properties in medicinal imaging, such as MRI, photoacoustic imaging, fluorescence imaging and PET/SPECT imaging. This paper reviews the recent reports of porphyrin derivatives as therapeutic agents used in tumor therapies, such as sonodynamic therapy, photodynamic therapy and radiotherapy, as well as imaging agents for multimodality tumor imaging. The limitations of porphyrin-based compounds in tumor treatments and future prospects are also summarized.

scholarly journals Light Absorption and Emission Dominated by Trions in the Type-I van der Waals Heterostructures

ACS Photonics ◽  
2021 ◽  
Author(s):  
Hyemin Bae ◽  
Suk Hyun Kim ◽  
Seungmin Lee ◽  
Minji Noh ◽  
Ouri Karni ◽  
...  
Keyword(s):  
Light Absorption ◽  
Van Der Waals ◽  
Type I ◽  
Van Der Waals Heterostructures ◽  
Absorption And Emission

scholarly journals A Novel Quinoxaline-Rhodamine Conjugate for a Simple and Efficient Detection of Hydrogen Sulphate Ion

Compounds ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 29-40
Author(s):  
Sutapa Sahu ◽  
Yeasin Sikdar ◽  
Riya Bag ◽  
Dilip K. Maiti ◽  
José P. Cerón-Carrasco ◽  
...  
Keyword(s):  
Solid Phase ◽  
Detection Limits ◽  
Hydrogen Sulfate ◽  
Absorption And Emission ◽  
Conjugate System ◽  
Colorimetric Chemosensor ◽  
Simple Strategy ◽  
Efficient Detection ◽  
Hydrogen Sulphate

This work presents the development of a quinoxaline and rhodamine conjugate system that acts as a colorimetric chemosensor for hydrogen sulfate (HSO4−) ions in methanol media. This sensor has been characterized both theoretically and experimentally. The detection limits for HSO4− are small as 0.71 µM and 3.8 µM for the absorption and emission experiments, respectively. The effectiveness of the probe in recognizing HSO4− both in gel and solid phase is evaluated as well. Thus, this works presents a simple strategy to detect the environmental HSO4− pollutant event at tiny concentrations.

Tracing absorption and emission characteristics of halogen-bonded ion pairs involving halogenated imidazolium species

2021 ◽  
Vol 23 (12) ◽  
pp. 7480-7494
Author(s):  
Sarah Karbalaei Khani ◽  
Bastian Geissler ◽  
Elric Engelage ◽  
Patrick Nuernberger ◽  
Christof Hättig
Keyword(s):  
Ion Pairs ◽  
Ion Pairing ◽  
Emission Characteristics ◽  
Absorption And Emission ◽  
Spectroscopic Signatures

Spectroscopic signatures of ion-pairing are identified by variation of counterion and substitution and comparison with theory.

Cyanophenoxy-Substituted Silicon Phthalocyanines for Low Threshold Voltage n-Type Organic Thin-Film Transistors

2021 ◽  
Author(s):  
Benjamin King ◽  
Andrew J. Daszczynski ◽  
Nicole A. Rice ◽  
Alexander J. Peltekoff ◽  
Nathan J. Yutronkie ◽  
...  
Keyword(s):  
Thin Film ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Organic Thin Film Transistors ◽  
Organic Thin Film ◽  
Silicon Phthalocyanines ◽  
Low Threshold

scholarly journals Two Symmetrical Squarylium Cyanine Dyes: Synthesis, Photophysics and Antifungal Activity in Saccharomyces cerevisiae

2020 ◽  
Vol 3 (1) ◽  
pp. 106
Author(s):  
Vanessa S. D. Gomes ◽  
João C. C. Ferreira ◽  
Renato E. F. Boto ◽  
Paulo Almeida ◽  
Maria João M. F. Sousa ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Minimum Inhibitory Concentration ◽  
Antifungal Activity ◽  
Emission Spectroscopy ◽  
Inhibitory Concentration ◽  
Analytical Techniques ◽  
Cyanine Dyes ◽  
Absorption And Emission ◽  
Nir Absorption ◽  
Absorption And Emission Spectroscopy

Two squarylium cyanine dyes were synthesized and characterized by the usual analytical techniques, including Vis-NIR absorption and emission spectroscopy. Their antifungal activity was evaluated, through the obtention of minimum inhibitory concentration (MIC) values, using yeasts of the species Saccharomyces cerevisiae as a biological model.

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