scholarly journals Dragon’s Blood Sap: Storage Stability and Antioxidant Activity

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2641 ◽  
Author(s):  
Juan Escobar ◽  
Cristina Prieto ◽  
Maria Pardo-Figuerez ◽  
José Lagaron
Keyword(s):  
Phenolic Compounds ◽  
Storage Stability ◽  
Uv Light ◽  
Light Exposure ◽  
Consumer Products ◽  
Effect Of Temperature ◽  
High Concentration ◽  
Dragon’S Blood ◽  
Different Temperatures ◽  
Ft Ir

Currently, consumers are demanding additive-free, fresher, and more-natural products. Dragon’s Blood Sap (DBS), the deep red latex of the specie of tree Croton lechleri (Müll. Arg.), contains a high concentration of phenolic compounds of great interest for the food, pharmaceutical, and cosmetic industries. These chemical compounds are highly susceptible to degradation. Therefore, DBS storage stability and its photo-oxidation was studied by Fourier transform infrared spectroscopy (FT-IR) and UV-Vis spectrophotometry for 39 days at different temperatures (4–21 °C) and relative humidities (0–56%), as well as under UV light exposure. It was observed that the degradation of phenolic compounds was reduced at 0% relative humidity (RH), not showing a significant effect of temperature in the range studied. UV light irradiation degraded DBS in a 20%. DBS has an exceptional high and stable antioxidant content (≥93% inhibition percentage of DPPH), which makes it a unique property to consider the DBS as an antioxidant agent or ingredient for consumer products formulations.

scholarly journals The effect of temperature on persistence of SARS-CoV-2 on common surfaces

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Shane Riddell ◽  
Sarah Goldie ◽  
Andrew Hill ◽  
Debbie Eagles ◽  
Trevor W. Drew
Keyword(s):  
Uv Light ◽  
Risk Mitigation ◽  
Survival Rates ◽  
Environmental Stability ◽  
Effect Of Temperature ◽  
Viral Loads ◽  
Different Temperatures ◽  
C 30 ◽  
D Values

Abstract Background The rate at which COVID-19 has spread throughout the globe has been alarming. While the role of fomite transmission is not yet fully understood, precise data on the environmental stability of SARS-CoV-2 is required to determine the risks of fomite transmission from contaminated surfaces. Methods This study measured the survival rates of infectious SARS-CoV-2, suspended in a standard ASTM E2197 matrix, on several common surface types. All experiments were carried out in the dark, to negate any effects of UV light. Inoculated surfaces were incubated at 20 °C, 30 °C and 40 °C and sampled at various time points. Results Survival rates of SARS-CoV-2 were determined at different temperatures and D-values, Z-values and half-life were calculated. We obtained half lives of between 1.7 and 2.7 days at 20 °C, reducing to a few hours when temperature was elevated to 40 °C. With initial viral loads broadly equivalent to the highest titres excreted by infectious patients, viable virus was isolated for up to 28 days at 20 °C from common surfaces such as glass, stainless steel and both paper and polymer banknotes. Conversely, infectious virus survived less than 24 h at 40 °C on some surfaces. Conclusion These findings demonstrate SARS-CoV-2 can remain infectious for significantly longer time periods than generally considered possible. These results could be used to inform improved risk mitigation procedures to prevent the fomite spread of COVID-19.

scholarly journals Plastics in robots: a degradation study of a humanoid skin mask made of soft urethane elastomer

2022 ◽  
Vol 10 (1) ◽  
Author(s):  
Anna Micheluz ◽  
Eva Mariasole Angelin ◽  
Julia Sawitzki ◽  
Marisa Pamplona
Keyword(s):  
Mass Spectrometry ◽  
Inner Core ◽  
Uv Light ◽  
Light Exposure ◽  
Evolved Gas Analysis ◽  
Photochemical Activity ◽  
Gas Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
High Concentration ◽  
Photo Oxidation

AbstractUnderstanding the degradation of plastic materials is a big challenge for curators, conservators and conservation scientists in museums worldwide aiming to preserve their collections due to the variety of formulations of synthetic polymers and pigments. The conservation of polyurethane (PUR) based objects is challenging because they can suffer from extensive degradation. Particularly PUR elastomers can degrade shortly after their production, as occurred to the mask of the Japanese robot SAYA, which within 8 years suffered from two large tears, discoloration and stickiness. This research aims at studying the degradation phenomena of the androids’ synthetic skin. Better knowledge of the chemical composition of the mask and the chemical and physical decay will contribute to planning a suitable stabilization treatment. Within a multi-analytical approach, colorimetric and microscopic investigations highlighted discolored areas, which showed further color changes within a five months monitoring campaign, confirming the instability of the material likely due to ongoing degradation. Raman microscopy allowed the identification of Pigment White 6 (titanium dioxide TiO2) in the anatase form, known to promote the photosensitivity of PUR substrates towards ultraviolet (UV) light. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy identified the PUR composition of the mask, the presence of phthalates as plasticizers and suggested the formation of quinone chromophores in the polymer structure as a result of photo-oxidation, possibly responsible for the mask yellowing. Evolved gas analysis-mass spectrometry (EGA-MS) and double-shot-gas chromatography/mass spectrometry (TD/Py–GC/MS) analyses support the characterization of the formulation of the mask as being made of methylene diphenyl diisocyanate (MDI) PUR ether elastomer. Plasticizers in high concentration, mainly diisononyl phthalate (DINP) and bis(2-ethylhexyl)phthalate (DEHP), and the UV stabilizer Tinuvin 328 were also detected. In addition, the presence of styrene-acrylonitrile (SAN) could also contribute to the mask’s chemical instability. More amount of UV stabilizer and phthalates were detected at the surface (contributing to its stickiness) than in the inner core. The degradation of the mask results from the light susceptibility of MDI PUR ether and SAN, as well as the higher photochemical activity of anatase. The mask was transferred on to a mannequin and placed in the storage area to prevent light exposure and photo-oxidation. As loose edges had to be stabilized, tests were conducted and adhesive stripes glued with a PUR dispersion were selected for keeping the head’s shape. The novelty of this study is the implementation of conservation science on the study of androids with PUR elastomeric components in robotic collections, which are becoming increasingly popular in technical museums, however still seldomly studied.

scholarly journals Degradation of Dazomet by Thermal Fenton and Photo-Fenton Processes under UV and Sun lights at Different Temperatures

2018 ◽  
Vol 15 (2) ◽  
pp. 158-168
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thermodynamic Functions ◽  
Reaction Rate ◽  
Uv Light ◽  
Reaction Rate Constant ◽  
Effect Of Temperature ◽  
Fenton Process ◽  
Fenton Reagents ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Sun Light

In this research, the degradation of Dazomet has been studied by using thermal Fenton process and photo-Fenton processes under UV and lights sun. The optimum values of amounts of the Fenton reagents have been determined (0.07g FeSO4 .7H2O, 3.5µl H2O2) at 25 °C and at pH 7 where the degradation percentages of Dazomet were recorded high. It has been found that solar photo Fenton process was more effective in degradation of Dazomet than photo-Fenton under UV-light and thermal Fenton processes, the percentage of degradation of Dazomet by photo-Fenton under sun light are 88% and 100% at 249 nm and 281 nm respectively, while the percentages of degradation for photo-Fenton under UV-light are 87%, 96% and for thermal Fenton are 70% and 66.8% at 249 nm and 281 nm respectively. In this research the effect of temperature on all the reactions has been studied in the range 25°C-45°C, it has been noticed that the reaction rate constant (k) has increased with increasing temperature, and the best percentage degradation of Dazomet was at 45°C in all processes, so, the thermodynamic functions ?G*, ?H*, ?S* have been calculated

The Use of FT-IR to Characterize Photosensitive Thermosets

1987 ◽  
Vol 41 (3) ◽  
pp. 476-478 ◽  
Author(s):  
Randy W. Snyder ◽  
Michael Yandrasits ◽  
Jeffrey T. Gotro
Keyword(s):  
Light Exposure ◽  
Effect Of Temperature ◽  
Circuit Boards ◽  
Cure Reaction ◽  
Ceramic Substrates ◽  
Heated Sample ◽  
Photosensitive Polymers ◽  
Silicon Chips ◽  
Ft Ir ◽  
Pattern Line

Photosensitive polymers are used extensively in the electronics industry to pattern line channels on silicon chips, ceramic substrates, and circuit boards. The photolytic process often requires an ultraviolet light exposure and subsequent bake to produce the required properties, prior to solvent development operations. An in situ FT-IR method was developed to assess the cross-linking reaction induced by UV exposure and investigate the effect of temperature on the overall reaction. The method employs a commercially available heated sample cell holder and an in-house fabricated fiber optic exposure tool. The UV-induced cure reaction was monitored as a function of time. The effect of bake temperature after exposure was also monitored.

scholarly journals Utilization of liquid product through pyrolysis of LDPE and C/LDPE as commercial wax

2021 ◽  
Author(s):  
Hasret Akgün ◽  
Ece Yapıcı ◽  
Zerrin Günkaya ◽  
AYSUN ÖZKAN ◽  
Müfide Banar
Keyword(s):  
Heating Rate ◽  
Liquid Product ◽  
Product Yield ◽  
Effect Of Temperature ◽  
Heating Rates ◽  
H Nmr ◽  
Elemental Analyses ◽  
Liquid Products ◽  
Different Temperatures ◽  
Ft Ir

Abstract Background In this study, pyrolysis of low-density polyethylene (LDPE) and LDPE with aluminum (C/LDPE) wastes was carried out with different heating rates (5-10-20°C/min) at different temperatures (400-600-800°C). The effect of temperature and heating rate on liquid product yield was investigated. Product yields of LDPE and C/LDPE wastes were compared, and optimum liquid products were analyzed to utilize as commercial waxes for future use. Methods To determine the parameters of pyrolysis wastes was investigated with proximate, elemental analysis, and TGA. The as-produced liquid from pyrolysis of wastes was characterized by different characteristic tools, such as elemental analyses, GC-MS analyzes, 1H-NMR tests, FT-IR spectra, the density, melting point, and carbon residue to compare commercial waxes. The characterization process was continued for the parameters with the optimum liquid products. Results As a result of pyrolysis, the highest liquid product yield was achieved at 800°C with 5°C/min heating rate (85.87 %), and at 600°C with 5°C/min heating rate (71.3 %) for LDPE and C/LDPE, respectively. The results indicated that the derived liquid products are similar to commercial heavy wax.

scholarly journals Hydrothermal Synthesis of Multi-Color Fluorescent Carbon Dots from Sappan Wood (Caesalpinia sappan) as an Acid-Base Indicator

2020 ◽  
Vol 71 (8) ◽  
pp. 106-112
Author(s):  
Adin Hasrudin ◽  
Zaenal Abidin ◽  
Nurul Hiedayati ◽  
Vicky Prajaputra
Keyword(s):  
Phenolic Compounds ◽  
Carbon Dots ◽  
Treatment Process ◽  
Uv Light ◽  
Alkaline Condition ◽  
Acid Base ◽  
Caesalpinia Sappan ◽  
Treated Sample ◽  
Yellow Orange ◽  
Ft Ir

Caesalpinia sappan L., known as sappan wood, has been extensively explored by many researchers because it contains various structural types of phenolic compounds. This study objectives are to investigate the effect of pH on the flourescent color of carbon dots (CDs) from sappan wood and its application as an acid-base indicator under UV light for the first time. CDs were synthesized through the hydrothermal route in ethanol solvents. The synthesized CDs were further characterized by UV-Vis spectrophotometry, fluorescence and Fourier Transform Infrared (FT-IR) spectroscopy. Based on the results, CD solutions performed multiple flourescent colors (yellow, orange and green) under UV light at 365 nm when the pH was adjusted to be 1, 3, 5, 7, 9 and 11. These multiple colors were produced because of the instability of phenolic compounds in the sample, especially brazilin which was easily oxidized to brazilein in alkaline condition. According to the FT-IR spectra, the most prominent differences of the sample before and after the treatment process was observed in the peak region ranging from 1500-1700 cm-1. The characteristic band of carbonyl groups was identified at 1697 cm-1 in the treated sample (pH 9), but it was unobserved in the spectrum of sappan wood and the treated sample (pH 5). The presence of carbonyl group can be assumed that brazilin has been oxidized to brazilein after the alkaline treatment process and making the flourescent color was gradually shifted from yellow to green. Under normal light, the sappan wood�s extract and CD solution produced yellow and red colors in acidic and alkaline conditions, respectively. However, only CD solutions which have yellow, orange and green emissions in different pH conditions under UV light. Therefore, the synthesized CDs can be used as an acid-base indicator in both different light conditions.

Predicting cold-water bleaching in corals: role of temperature, and potential integration of light exposure

2020 ◽  
Vol 642 ◽  
pp. 133-146
Author(s):  
PC González-Espinosa ◽  
SD Donner
Keyword(s):  
Coral Bleaching ◽  
Cold Water ◽  
Light Exposure ◽  
Light Attenuation ◽  
Florida Keys ◽  
Cold Temperature ◽  
Warm Water ◽  
Coral Tissue ◽  
Effect Of Temperature ◽  
Type I

Warm-water growth and survival of corals are constrained by a set of environmental conditions such as temperature, light, nutrient levels and salinity. Water temperatures of 1 to 2°C above the usual summer maximum can trigger a phenomenon known as coral bleaching, whereby disruption of the symbiosis between coral and dinoflagellate micro-algae, living within the coral tissue, reveals the white skeleton of coral. Anomalously cold water can also lead to coral bleaching but has been the subject of limited research. Although cold-water bleaching events are less common, they can produce similar impacts on coral reefs as warm-water events. In this study, we explored the effect of temperature and light on the likelihood of cold-water coral bleaching from 1998-2017 using available bleaching observations from the Eastern Tropical Pacific and the Florida Keys. Using satellite-derived sea surface temperature, photosynthetically available radiation and light attenuation data, cold temperature and light exposure metrics were developed and then tested against the bleaching observations using logistic regression. The results show that cold-water bleaching can be best predicted with an accumulated cold-temperature metric, i.e. ‘degree cooling weeks’, analogous to the heat stress metric ‘degree heating weeks’, with high accuracy (90%) and fewer Type I and Type II errors in comparison with other models. Although light, when also considered, improved prediction accuracy, we found that the most reliable framework for cold-water bleaching prediction may be based solely on cold-temperature exposure.

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

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