scholarly journals Ультрафиолетовая люминесценция и светорассеяние систем фотодитазина с альгинатом натрия, поли-N-винилпирролидоном и триптофаном-=SUP=-*-=/SUP=-

2019 ◽  
Vol 126 (6) ◽  
pp. 781
Author(s):  
Л.В. Беловолова ◽  
М.В. Глушков ◽  
Н.А. Аксенова ◽  
А.Б. Соловьева ◽  
О.В. Хасанова
Keyword(s):  
Ternary Complex ◽  
Rayleigh Scattering ◽  
Mutual Influence ◽  
Water Soluble ◽  
Polymer Systems ◽  
Fluorescence Parameters ◽  
Photo Oxidation ◽  
Oxidation Processes ◽  
Preparation Conditions ◽  
Scattering Spectra

As part of the study of polymer systems based on a chlorine photosensitizer, photodithazine (PD), photodynamic therapy was used to study the fluorescence and Rayleigh scattering spectra upon excitation at wavelengths lambdaex = 260, 280, 400, and 450 nm. Non-toxic water-soluble poly-N-vinylpyrrolidone (PVP) and vegetable polysaccharide were used as the polymer. sodium alginate (SA). The data of the PD-SA dual system is characterized by variability of characteristics depending on the preparation conditions, while in the PD-SA-PVP ternary complex, there is a favorable mutual influence of two SA and PVP polymers on the PD molecule, due to the creation of a local microenvironment of the active center PD with increased polarity . It was shown that the introduction of tryptophan (Trp), used as a substrate in model photo-oxidation processes, when testing the effectiveness of photosensitizers in the generation of singlet oxygen, does not significantly change the fluorescence parameters of the PD-SA-PVP complex.

scholarly journals Effect of Chitosan on the Activity of Water-Soluble and Hydrophobic Porphyrin Photosensitizers Solubilized by Amphiphilic Polymers

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1007
Author(s):  
Valeriya V. Kardumyan ◽  
Nadejda A. Aksenova ◽  
Victoria A. Timofeeva ◽  
Alexey V. Krivandin ◽  
Olga V. Shatalova ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
Amphiphilic Polymers ◽  
Model Reaction ◽  
Amphiphilic Polymer ◽  
Water Soluble ◽  
Pluronic F127 ◽  
Polymer Systems ◽  
Photo Oxidation ◽  
Porphyrin Photosensitizers ◽  
Trisodium Salt

In this work, we studied the photocatalytic activity of photosensitizers (PSs) of various natures solubilized with polyvinylpyrrolidone (PVP) and ternary block copolymer ethylene and propylene oxide Pluronic F127 (F127) in a model reaction of tryptophan photo-oxidation in water in the presence of chitosan (CT). Water-soluble compounds (dimegin and trisodium salt of chlorin e6 (Ce6)) and hydrophobic porphyrins (tetraphenylporphyrin (TPP) and its fluorine derivative (TPPF20)) were used as PSs. It was shown that the use of chitosan (Mw ~100 kDa) makes it possible to obtain a system whose activity is comparable to that of the photosensitizer-amphiphilic polymer systems. Thus, the previously observed drop in the photosensitizing activity of PS in the presence of a polysaccharide and amphiphilic polymers (AP) was absent in this case. At the same time, chitosan had practically no inhibitory effect on hydrophobic porphyrins solubilized by Pluronic F127.

REMOVAL OF METOPROLOL BY MEANS OF PHOTO-OXIDATION PROCESSES

2021 ◽  
Author(s):  
Osmín Avilés-García ◽  
Jaime Espino-Valencia ◽  
Arisbeht Mendoza-Zepeda ◽  
Kingsley Donkor ◽  
Sharon Brewer ◽  
...  
Keyword(s):  
Photo Oxidation ◽  
Oxidation Processes

Resonance Rayleigh Scattering Determination of Trace Hemin Basing on Aptamer-Modified Nanogold Catalysis of HAuCl4-Vitamine C

2013 ◽  
Vol 787 ◽  
pp. 400-403
Author(s):  
Jin Chao Dong ◽  
Ai Hui Liang ◽  
Zhi Liang Jiang
Keyword(s):  
Detection Limit ◽  
Rayleigh Scattering ◽  
Resonance Rayleigh Scattering ◽  
Serum Samples ◽  
Buffer Solution ◽  
Strong Resonance ◽  
Scattering Spectra ◽  
Vitamine C ◽  
Nanogold Catalysis

Hemin aptamer was used to modify gold nanoparticles (AuNPs) to obtain a stable aptamer-nanogold probe (AussDNA). In the condition of pH 8.0 Tris-HCl buffer solution containing 50mmol/L NaCl, the substrate chain of AussDNA was cracked by hemin to produce a short single-stranded DNA(ssDNA) and then further combined with hemin to form a stable hemin-ssDNA conjugate. The AuNPs released from AussDNA would be aggregated in the condition of 50mmol/L NaCl and exhibited a strong resonance Rayleigh scattering (RRS) peak at 368nm. Under the selected conditions, the increased RRS intensity (ΔI368nm) was linear to hemin concentration in the range of 5-750nmol/L, with a detection limit of 66 pmol/L. This RRS method was applied to determination of residual hemin in serum samples, with satisfactory results. The remnant AussDNA in the solution exhibited a strong catalytic activity on the gold particle reaction of HAuCl4-vitamine C (VC) that can be monitored by RRS technique at 368 nm. When the hemin concentration increased, the AussDNA decreased, the catalysis decreased, and the RRS intensity at 368nm decreased. The decreased RRS intensity ΔI368nmwas linear to the hemin concentration in the range of 1-200nmol/L, with a detection limit of 54 pmol/L. Accordingly, a sensitivity, selectivity, and simplicity new method of resonance Rayleigh scattering spectra to detect hemin using aptamer-modified nanogold as catalyst was established.

Treatment of textile dyeing wastewater using advanced photo-oxidation processes for decolorization and COD reduction

2021 ◽  
Vol 217 ◽  
pp. 350-357
Author(s):  
S. Khelifi ◽  
A. Choukchou-Braham ◽  
H.M. Sbihi ◽  
M. Azam, ◽  
S.I. Al-Resayes ◽  
...  
Keyword(s):  
Dyeing Wastewater ◽  
Cod Reduction ◽  
Photo Oxidation ◽  
Oxidation Processes ◽  
Textile Dyeing ◽  
Textile Dyeing Wastewater

scholarly journals Light absorption by polar and non-polar aerosol compounds from laboratory biomass combustion

2018 ◽  
Author(s):  
Deep Sengupta ◽  
Vera Samburova ◽  
Chiranjivi Bhattarai ◽  
Elena Kirillova ◽  
Lynn Mazzoleni ◽  
...  
Keyword(s):  
Light Absorption ◽  
Flow Reactor ◽  
Soluble Fraction ◽  
Chemical Properties ◽  
Water Soluble ◽  
Biomass Combustion ◽  
Absorption Properties ◽  
Oxidation Processes ◽  
Aerosol Mass ◽  
Physical Processing

Abstract. Fresh and atmospherically aged biomass-burning (BB) aerosol mass is mostly comprised of black carbon (BC) and organic carbon (OC) with its light-absorbing fraction – brown carbon (BrC). There is a lack of data on the physical and chemical properties of atmospheric BB aerosols, leading to high uncertainties in estimates of the BB impact on air quality and climate, especially for BrC. The polarity of chemical compounds influences their fate in the atmosphere including wet/dry deposition and chemical and physical processing. So far, most of the attention has been given to the water-soluble (polar) fraction of BrC, while the non-polar BrC fraction has been largely ignored. In the present study, the light absorption properties of polar and non-polar fractions of fresh and aged BB emissions were examined to estimate the contribution of different-polarity organic compounds to the light absorption properties of BB aerosols. In our experiments, four globally and regionally important fuels were burned under flaming and smoldering conditions in DRI’s combustion chamber. To mimic atmospheric oxidation processes (5–7 days), BB emissions were aged using an oxidation flow reactor (OFR). Fresh and OFR-aged BB aerosols were collected on filters and extracted with water and hexane to study absorption properties of polar and non-polar organic species. Spectrophotometric measurements over the 190 to 900 nm wavelength range showed that the non-polar (hexane-soluble) fraction is 2–3 times more absorbing than the polar (water-soluble) fraction. However, an increased absorbance was observed for the water extracts of oxidized/aged emissions while the absorption of the hexane extracts was lower for the aged emissions. Comparing the absorption Ångström Exponent (AAE) values, we observed changes in the light absorption properties of BB aerosols with aging that was dependent on the fuel types. The light absorption by HUmic LIke Substances (HULIS) was found to be higher in fuels characteristic of the southwestern USA. The absorption of the HULIS fraction was lower for OFR-aged BB emissions. Comparison of the light absorption properties of different polarity extracts (water, hexane, HULIS) provides insight into the chemical nature of BB BrC and its transformation during oxidation processes.

SYNTHESIS AND OPTICAL PROPERTIES OF WATER SOLUBLE ZnSe NANOCRYSTALS

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3881-3884 ◽  
Author(s):  
N. Murase ◽  
M. Y. Gao ◽  
N. Gaponik ◽  
T. Yazawa ◽  
J. Feldmann
Keyword(s):  
Ph Value ◽  
Water Soluble ◽  
Final Solution ◽  
Blue Fluorescence ◽  
Wet Chemistry ◽  
Preparation Conditions ◽  
Transmission Electron ◽  
Mean Size ◽  
Surface Capping ◽  
Znse Nanocrystals

ZnSe nanocrystals are prepared in water by a wet chemistry method. By selecting an appropriate pH value and surface-capping agents, a whitish blue fluorescence peaking at 470 nm is observed under ZV irradiation. The intensity of this fluorescence increases dramatically under reflux and saturates after ~ 40 hrs. The final mean size of the ZnSe nanocrystals measured by transmission electron microscopy is aboyt 2 nm in diameter. The quantum efficiency of the fluorescence form the final solution is estimated to be ~1%, although the preparation conditions have not yet been completely optimized. These properties are discussed in comparison with those of similarly prepared CdTe and differently prepared ZnSe nanocrystals.

Sign in / Sign up

Export Citation Format

Share Document