scholarly journals Stability and Photoisomerization of Stilbenes Isolated from the Bark of Norway Spruce Roots

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1036
Author(s):  
Harri Latva-Mäenpää ◽  
Riziwanguli Wufu ◽  
Daniel Mulat ◽  
Tytti Sarjala ◽  
Pekka Saranpää ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Uv Light ◽  
Light Exposure ◽  
Fluorescent Light ◽  
Spectroscopic Techniques ◽  
Functional Ingredients ◽  
The Stability ◽  
Antibacterial And Antifungal ◽  
New Compounds ◽  
And Storage

Stilbenes or stilbenoids, major polyphenolic compounds of the bark of Norway spruce (Picea abies L. Karst), have potential future applications as drugs, preservatives and other functional ingredients due to their antioxidative, antibacterial and antifungal properties. Stilbenes are photosensitive and UV and fluorescent light induce trans to cis isomerisation via intramolecular cyclization. So far, the characterizations of possible new compounds derived from trans-stilbenes under UV light exposure have been mainly tentative based only on UV or MS spectra without utilizing more detailed structural spectroscopy techniques such as NMR. The objective of this work was to study the stability of biologically interesting and readily available stilbenes such as astringin and isorhapontin and their aglucones piceatannol and isorhapontigenin, which have not been studied previously. The effects of fluorescent and UV light and storage on the stability of trans stilbenes were assessed and the identification and characterisation of new compounds formed during our experiments were carried out by chromatographic (HPLC, GC) and spectroscopic techniques (UV, MS, NMR). The stilbenes undergo a trans to cis isomerisation under extended UV irradiation by intramolecular cyclisation (by the formation of a new C-C bond and the loss of two hydrogens) to phenanthrene structures. The characterised compounds are novel and not described previously.

scholarly journals COMPARISON BETWEEN CUSTOMS PREPARATIONS AND WORKOUT PREPARATIONS FOR PESTICIDE PROFENOFOS FROM DIFFERENT SOURCES AND UNDER SPECIFIC ENVIRONMENTAL CONDITIONS

2021 ◽  
Vol 21 (No 1) ◽  
Author(s):  
Hala. M. Ibrahim
Keyword(s):  
Uv Light ◽  
Degradation Products ◽  
Light Exposure ◽  
Sunlight Exposure ◽  
Factors Affecting ◽  
Trade Name ◽  
Before And After ◽  
The Stability ◽  
And Storage ◽  
Different Sources

Four generic profenfos formulations under trade name Camkron and Tiliton 72% EC (customs, workout) for each of those, which currently applied in Egypt from different companies were studied for the effects of sunlight exposure, UV-light, PH and storage on the stability of profenofos, its respective impurity 4-bromo-2-chlorophenol content and water as a relevant impurity. Exposure to sunlight, UV-light at 16 hours and storage for 14 days at 54±2o C indicated various degradation effects on profenofos content and increase the formation of its impurity 4-bromo-2-chlorophenol and the change in PH in long period cause breakdown of the active substance instability of some component. The storage of profenofos at intervals of 3, 7 and 14 days at 54 ± 2o C from the results obtained showed serious effects on the rate of degradation of profenofos and the increase in the rate of formation of 4-bromo-2-chlorophenol, as well as on sunlight, UV-light exposure, for all of the profenofos formulations under study. It found that the Camkron (workout) is invalid for use it may be due to several factors affecting the consistency of the formulation of profenofos in the manufacturing process, the origins of technical materials, the use of various forms of adjuvants and the long storage time in poor conditions. Analysis before and after storage, sunlight exposure, UV-light using GC-MS identified four degradation products: 4-bromo-2-chlorophenol, O-(4-bromophenyl) O-ethyl S-propyl phosphorothioate, O-(2-chlorophenyl) O-ethyl S-propyl phosphorothioate and O-(4-bromo-2-chlorophenyl) S-propyl hydrogen phosphorothioate and also used IR spectra.

scholarly journals Stability and ocular biodistribution of topically administered PLGA nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sean Swetledge ◽  
Renee Carter ◽  
Rhett Stout ◽  
Carlos E. Astete ◽  
Jangwook P. Jung ◽  
...  
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Polymeric Nanoparticles ◽  
Plga Nanoparticles ◽  
Eye Disease ◽  
Control Group ◽  
Eye Tissues ◽  
Nanoparticle Morphology ◽  
The Stability

AbstractPolymeric nanoparticles have been investigated as potential delivery systems for therapeutic compounds to address many ailments including eye disease. The stability and spatiotemporal distribution of polymeric nanoparticles in the eye are important regarding the practical applicability and efficacy of the delivery system in treating eye disease. We selected poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with lutein, a carotenoid antioxidant associated with eye health, as our model ophthalmic nanodelivery system and evaluated its stability when suspended in various conditions involving temperature and light exposure. We also assessed the ocular biodistribution of the fluorescently labeled nanoparticle vehicle when administered topically. Lutein-loaded nanoparticles were stable in suspension when stored at 4 °C with only 26% lutein release and no significant lutein decay or changes in nanoparticle morphology. When stored at 25 °C and 37 °C, these NPs showed signs of bulk degradation, had significant lutein decay compared to 4 °C, and released over 40% lutein after 5 weeks in suspension. Lutein-loaded nanoparticles were also more resistant to photodegradation compared to free lutein when exposed to ultraviolet (UV) light, decaying approximately 5 times slower. When applied topically in vivo, Cy5-labled nanoparticles showed high uptake in exterior eye tissues including the cornea, episcleral tissue, and sclera. The choroid was the only inner eye tissue that was significantly higher than the control group. Decreased fluorescence in all exterior eye tissues and the choroid at 1 h compared to 30 min indicated rapid elimination of nanoparticles from the eye.

Synthesis and characterization of novel poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive

2020 ◽  
Vol 98 (12) ◽  
pp. 755-763
Author(s):  
Hamid Reza Ghayeni ◽  
Reza Razeghi ◽  
Abolfazl Olyaei
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Sodium Acrylate ◽  
Spectroscopic Techniques ◽  
Effective Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cds Nanorods ◽  
Transmission Electron

Cadmium sulfide nanorods with a length of 69 nm have been prepared by using Cd(OAc)2.2H2O and S8 at 125 °C in the presence of triethylenetetramine as the template agent and coordination agent and characterized by using X-ray diffraction, transmission electron microscopy, FTIR, photoluminescence, and UV–vis absorption spectroscopic techniques. Photocopolymerization of glycidyl methacrylate (GMA) and sodium acrylate (SA) was carried out using CdS nanorods as a photocatalyst under UV light exposure at 400 nm in the presence of β-cyclodextrin (β-CD). To optimization of the effective parameters on the synthesis of copolymer nanocomposite, the amounts of initiator, monomers, and β-CD, duration of pre-deoxygenation, and light wavelength were evaluated. Ring opening of poly(GMA-co-SA)/CdS nanocomposite with NaN3 afforded poly(HAzPMA-co-SA)/CdS nanocomposite and subsequent mixing with RDX in DMF led to the formation of poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive. All of the copolymer nanocomposites were characterized using various tools of instrumental analysis.

scholarly journals Quantitative Imaging and In Situ Concentration Measurements of Quantum Dot Nanomaterials in Variably Saturated Porous Media

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Burcu Uyuşur ◽  
Preston T. Snee ◽  
Chunyan Li ◽  
Christophe J. G. Darnault
Keyword(s):  
Porous Media ◽  
Quantum Dot ◽  
Light Transmission ◽  
Water Saturation ◽  
Uv Light ◽  
Light Exposure ◽  
Fluorescence Method ◽  
Fluorescent Light ◽  
Subsurface Environment

Knowledge of the fate and transport of nanoparticles in the subsurface environment is limited, as techniques to monitor and visualize the transport and distribution of nanoparticles in porous media and measure their in situ concentrations are lacking. To address these issues, we have developed a light transmission and fluorescence method to visualize and measure in situ concentrations of quantum dot (QD) nanoparticles in variably saturated environments. Calibration cells filled with sand as porous medium and various known water saturation levels and QD concentrations were prepared. By measuring the intensity of the light transmitted through porous media exposed to fluorescent light and by measuring the hue of the light emitted by the QDs under UV light exposure, we obtained simultaneously in situ measurements of water saturation and QD nanoparticle concentrations with high spatial and temporal resolutions. Water saturation was directly proportional to the light intensity. A linear relationship was observed between hue-intensity ratio values and QD concentrations for constant water saturation levels. The advantages and limitations of the light transmission and fluorescence method as well as its implications for visualizing and measuring in situ concentrations of QDs nanoparticles in the subsurface environment are discussed.

Strength Properties of Flexible Geogrids Under Indoor and Outdoor Ultraviolet Exposure

2003 ◽  
Vol 1849 (1) ◽  
pp. 221-230 ◽  
Author(s):  
Chiwan Wayne Hsieh ◽  
Chien Kuei Lin
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Carbon Black ◽  
Uv Light ◽  
Light Exposure ◽  
Outdoor Exposure ◽  
Uv Exposure ◽  
Fluorescent Light ◽  
Exposure Condition ◽  
Coating Materials

The outdoor ultraviolet (UV) light exposure program according to ASTM D5970 and the indoor UV fluorescent lamp device according to ASTM G154 were used to evaluate the UV degradation in test polyester geogrids. Eighteen months’ worth of data were obtained from the outdoor program. UV-A-340 lamps and exposure condition No. 7 were used for the indoor program. The outdoor exposure program was conducted at Pingtung, in southern Taiwan. The annual sunlight exposure energy was 4,263.50 MJ/m2. The accumulated annual UV-A and UV-B energies were 256.56 and 0.83 MJ/m2, respectively. The tensile strength of the test geogrids decreased as the outdoor exposure increased, but the decrease in the rate of tensile strength also lessened as UV exposure increased. Carbon black and antioxidants contained in the coating materials have a significant influence on the rate of degradation for the test geogrids; 2% carbon black and 1% antioxidant by weight are recommended. The proportions of average retained ultimate tensile strength for 1 month, 12 months, and 18 months of outdoor exposure were 88%, 71%, and 66%, respectively. The tensile strength half-life cycle due to UV exposure was greater than 18 months. Similar behavior was also observed for the elongation at break. However, no clear trend was found for strength at 5% strain due to UV exposure. The reduction factors due to 18 months of outdoor exposure varied from 1.27 to 1.99. The average reduction factor was about 1.60. The reduction in ultimate tensile strength under 180 h of UV exposure in the indoor UV exposure test program was very significant. However, the rate of lost tensile strength for the second and third 180-h UV exposure was very small. The average retained tensile strengths for the geogrids under 180-h and 540-h exposures were 81% and 77%, respectively. The effect of 540-h fluorescent light exposure on the tensile strength of polyester geogrids coated with polyvinyl chloride was equivalent to 151 days of outdoor exposure at Pingtung.

scholarly journals Toward Commercialization of Stable Devices: An Overview on Encapsulation of Hybrid Organic-Inorganic Perovskite Solar Cells

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 519
Author(s):  
Clara A. Aranda ◽  
Laura Caliò ◽  
Manuel Salado
Keyword(s):  
Solar Cells ◽  
Uv Light ◽  
Light Exposure ◽  
Perovskite Solar Cells ◽  
Depth Analysis ◽  
Environmentally Sensitive ◽  
The Stability ◽  
Stability Issues ◽  
Conversion Efficiencies ◽  
Reliable Testing

Perovskite solar cells (PSCs) represent a promising technology for energy harvesting due to high power conversion efficiencies up to 26%, easy manufacturing, and convenient deposition techniques, leading to added advantages over other contemporary competitors. In order to promote this technology toward commercialization though, stability issues need to be addressed. Lately, many researchers have explored several techniques to improve the stability of the environmentally-sensitive perovskite solar devices. Challenges posed by environmental factors like moisture, oxygen, temperature, and UV-light exposure, could be overcome by device encapsulation. This review focuses the attention on the different materials, methods, and requirements for suitable encapsulated perovskite solar cells. A depth analysis on the current stability tests is also included, since accurate and reliable testing conditions are needed in order to reduce mismatching involved in reporting the efficiencies of PSC.

scholarly journals Effects of UV-Light, Temperature and Storage on the Stability and Biological Effectiveness of Some Insecticides

2012 ◽  
Vol 52 (2) ◽  
pp. 275-280 ◽  
Author(s):  
Mahmoud Soliman
Keyword(s):  
Uv Light ◽  
Immature Stages ◽  
Light Storage ◽  
Degradation Rates ◽  
Residual Level ◽  
Different Temperatures ◽  
Biological Effectiveness ◽  
The Stability ◽  
And Storage ◽  
Uv Rays

Effects of UV-Light, Temperature and Storage on the Stability and Biological Effectiveness of Some InsecticidesThe degradation and biological effectiveness of five insecticides, ES-Fenvalerate (Soumi Gold), pirimicarb (Afox), imidacloprid (Emax), buprofenzin (Ablloud) and methomyl (Methiolate) in their aqueous preparations and emulsifiable concentrates, on immature stages of whitefly insectBemisia tabaci. when exposed to UV-light, two different temperatures and daylight and dark storage after exposure intervals was studied. The results indicated the degradation rates of the five tested insecticides varied according to the chemical structure, time of exposure and wavelength of UV-rays used. Of all the five insecticides, methomyl was the most affected by UV-rays. Losses of ES-Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl within this period were 11.30, 14.80, 29.03, 31.83 and 39%, respectively after one hour to UV-ray exposure. A significant increase in LC50value was obtained when ES-Fenvalerate in aqueous preparation was exposed to UV-light for 6 hr. The LC50values and their confidence ranges in aqueous preparations and emulsifiable concentrates were 107.5 ppm (51.7-199.2) and 93.10 ppm (48.3-150.4). The residual level of Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl were 13.52, 17.54 ppm; 12.67, 15.87 ppm; 11.78, 16.47 ppm; 11.38, 14.73 ppm; and 11.36, 11.83 ppm for two days exposed to daylight and dark storage. Insecticides could be arranged according to LC50values at zero-time as follow: ES-Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl. The corresponding values of LC50were 3.40, 15.4, 15.6, 16.2 and 23.5 ppm for daylight storage. On the other hand, the dark storage exposure for the tested insecticides could be arranged according to LC50values as follow: ES-Fenvalerate, imidacloprid, pirimicarb, buprofenzin and methomyl. The corresponding LC50were 3.20, 14.8, 14.9, 15.9 and 21.3 ppm, respectively. In general, the amount recovered after a one day, 45°C exposure were 14.63, 12.84, 12.79, 12.14 and 11.76 ppm, for ES-Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl, respectively. While the amounts recovered after a three day 45°C exposure were 9.28, 8.34, 7.76, 7.72 and 5.83 ppm for ES-Fenvalerate, pirimicarb, imidacloprid, buprofenzin and methomyl, respectively. Efficiency against whitefly insect,B. tabaciimmature stages was affected when aqueous preparations of the five tested insecticides were stored at 45°C for one and three days, compared to those stored under normal condition of 25°C for the same periods of time. Generally it could be concluded that buprofenzin n and methomyl, were more affected by UV-light, storage and temperature than ES-Fenvalerate, pirimicarb, imidacloprid.

Volatile Compounds in UHT-Sterilized Milk During Fluorescent Light Exposure and Storage in the Dark1

1979 ◽  
Vol 42 (3) ◽  
pp. 256-258 ◽  
Author(s):  
R. S. MEHTA ◽  
R. BASSETTE
Keyword(s):  
High Temperature ◽  
Volatile Compounds ◽  
Light Exposure ◽  
Taste Panel ◽  
The Other ◽  
Fluorescent Light ◽  
Chromatographic Peaks ◽  
Sterilized Milk ◽  
And Storage ◽  
Ultra High Temperature

When ultra-high-temperature sterilized milk (140 C for 3.5 sec) was exposed to fluorescent light over a 30-day period at 22 C, acetaldehyde, propanal, pentanal, and hexanal increased in concentration. On storage of the milk in the dark, after a 2-week period of light exposure, these same compounds decreased in concentration. No characteristic patterns were noticed in the other chromatographic peaks. When a five-fold diluted distillate of light-exposed milk was added to normal milk, a taste-panel criticized the milk as pronounced oxidation, tallowy or oily.

PHYTOCHEMICAL CHARACTERIZATION AND TANNIN STABILITY TEST FROM KLUWEK (Pangium edule Reinw)

2019 ◽  
Vol 1 (02) ◽  
pp. 44-49
Author(s):  
Siti Warnasih ◽  
Uswatun Hasanah
Keyword(s):  
Secondary Metabolite ◽  
Uv Light ◽  
Heating Temperature ◽  
Natural Dye ◽  
Stability Test ◽  
Tannin Content ◽  
The Stability ◽  
And Storage ◽  
Duration Of Heating ◽  
Uv Rays

One of the herbs that can be used as a source of natural dye is the kluwek which is brown. This study aims to determine the type of secondary metabolite compounds producing color, and to determine the stability of tannin in various conditions such as pH, oxidizing, UV rays, heating temperature, and storage using UV-Vis spectrophotometry method. This research includes preparation of kluwek, extraction with acetone:water (7:3) with maceration method, phytochemical test (tannin, flavonoid, carotenoid, and anthocyanin) and total tannins, and tannin stability test on various pH, oxidizing, UV rays, temperature and duration of heating, and storage using the UV-Vis spectrophotometry method. The results obtained are kluwek extract containing tannin, flavonoid, carotenoid, and anthocyanin compounds, and total tannins 2.80%. Based on the tannin content, kluwek extract stable at pH 6-7, heating 60-80 oC, and storage up to 9 days at temperature 27 C, and kluwek extract unstable when contact with 1% H2O2, UV light, and if kept at cold temperature (10 ?C).

scholarly journals Antimicrobial Activity of TiO2Nanoparticle-Coated Film for Potential Food Packaging Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Siti Hajar Othman ◽  
Nurul Raudhah Abd Salam ◽  
Norhazlizam Zainal ◽  
Roseliza Kadir Basha ◽  
Rosnita A. Talib
Keyword(s):  
Antimicrobial Activity ◽  
Food Packaging ◽  
Uv Light ◽  
Light Exposure ◽  
Antimicrobial Property ◽  
Fluorescent Light ◽  
Packaging Film ◽  
E Coli ◽  
Coated Film ◽  
Potential Food

Recent uses of titanium dioxide (TiO2) have involved various applications which include the food industry. This study aims to develop TiO2nanoparticle-coated film for potential food packaging applications due to the photocatalytic antimicrobial property of TiO2. The TiO2nanoparticles with varying concentrations (0–0.11 g/ 100 mL organic solvent) were coated on food packaging film, particularly low density polyethylene (LDPE) film. The antimicrobial activity of the films was investigated by their capability to inactivateEscherichia coli(E. coli) in an actual food packaging application test under various conditions, including types of light (fluorescent and ultraviolet (UV)) and the length of time the film was exposed to light (one–three days). The antimicrobial activity of the TiO2nanoparticle-coated films exposed under both types of lighting was found to increase with an increase in the TiO2nanoparticle concentration and the light exposure time. It was also found that the antimicrobial activity of the films exposed under UV light was higher than that under fluorescent light. The developed film has the potential to be used as a food packaging film that can extend the shelf life, maintain the quality, and assure the safety of food.

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