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.

The Effects of Temperature on the Stiffness Modulus of Dense Graded Asphalt Mixtures

2013 ◽  
Vol 423-426 ◽  
pp. 997-1000
Author(s):  
Ali Mohamed Abudullahi ◽  
Kwong Yiing Ting ◽  
Wee Kang Choong ◽  
Boon Hoe Goh
Keyword(s):  
Design Method ◽  
Effect Of Temperature ◽  
Asphaltic Concrete ◽  
Stiffness Modulus ◽  
Different Temperatures ◽  
Indirect Tensile ◽  
N Loading ◽  
C 30 ◽  
Styrene Butadiene

This study aimed to investigate the effect of temperature on stiffness modulus of asphaltic concrete. The asphaltic concrete mixture were prepared based on Marshall Mix Design method using two different types of bitumen, the 80/100 penetration grade bitumen (80/100 PGB) and Styrene-Butadiene-Styrene (SBS), both with five percent bitumen content. Indirect Tensile Stiffness Modulus (ITSM) test of 1000 N loading was then performed at three different temperatures (25 °C, 30 °C and 40 °C). The results showed that stiffness modulus decreases with increases in temperature for both 80/100 PGB and SBS, which shows the important role of temperature to stiffness modulus of asphaltic concrete. Also, the results showed a higher stiffness modulus for SBS mixtures compare to that of 80/100 PGB mixtures.

Inactivation Rates of Cronobacter spp. and Selected Other Bacterial Strains in Powdered Infant Formulae Stored at Different Temperatures

2010 ◽  
Vol 73 (5) ◽  
pp. 839-848 ◽  
Author(s):  
M. C. KANDHAI ◽  
M. W. REIJ ◽  
M. van SCHOTHORST ◽  
L. G. M. GORRIS ◽  
M. H. ZWIETERING
Keyword(s):  
Distribution Model ◽  
Effect Of Temperature ◽  
Powdered Infant Formula ◽  
Bacterial Cells ◽  
Bacterial Strains ◽  
Infant Formulae ◽  
Different Temperatures ◽  
D Values ◽  
Log Linear ◽  
Increasing Temperature

The aim of this study was to determine the survival of two strains of Cronobacter (Enterobacter sakazakii) and six other bacterial strains inoculated into dry powdered infant formula (PIF) stored for 22 weeks at several temperatures between 7 and 42°C. The experimental setup involved a relatively high initial concentration of bacteria, around 104 CFU/g of powder, and enumeration of survivors with a minimum detection level of 100 CFU/g. For all strains tested, it was found that the number of bacterial cells decreased faster with increasing temperature. Cronobacter spp. cells generally survived better at high temperatures (37 and 42°C) than the other bacteria, while such a difference in survival was not apparent at other temperatures. To describe the effect of temperature on survival, both the Weibull distribution model and the log-linear model were tested. At 22°C, decline rates of 0.011 and 0.008 log units per day were found for Cronobacter sakazakii ATCC 29544 and Cronobacter strain MC10, respectively. Assuming a linear relationship between log-transformed D-values and temperature, z-values estimated for C. sakazakii ATCC 29544 and Cronobacter MC10 were 13.3 and 23.5°C, respectively. Such differences found in resistance among Cronobacter spp. would be relevant to consider when establishing quantitative risk assessments on consumer risks related to PIF.

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

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 Bose–Einstein condensation in one-dimensional optical lattices: Bogoliubov’s approximation and beyond

2016 ◽  
Vol 94 (7) ◽  
pp. 697-703
Author(s):  
Mohamed K. Al-Sugheir ◽  
Mufeed A. Awawdeh ◽  
Humam B. Ghassib ◽  
Emad Alhami
Keyword(s):  
Lattice Points ◽  
Effect Of Temperature ◽  
Einstein Condensation ◽  
Condensate Fraction ◽  
Number Density ◽  
One Dimensional ◽  
Bose Einstein Condensation ◽  
Different Temperatures ◽  
Bose Einstein

Bose–Einstein condensation in a finite one-dimensional atomic Bose gas trapped in an optical lattice is studied within Bogoliubov’s approximation and then beyond this approximation, within the static fluctuation approximation. A Bose–Hubbard model is used to construct the Hamiltonian of the system. The effect of the potential strength on the condensate fraction is explored at different temperatures; so is the effect of temperature on this fraction at different potential strengths. The role of the number of lattice points (the size effect) at constant number density (the filling factor) is examined; so is the effect of the number density on the condensate fraction. The results obtained are compared to other published results wherever possible.

Effect of temperature and soluble solid on Bacillus subtilis and Bacillus licheniformis spore inactivation and quality degradation of pineapple juice

2021 ◽  
pp. 108201322110191
Author(s):  
Evelyn ◽  
Syelvia Putri Utami ◽  
Chairul
Keyword(s):  
Bacillus Subtilis ◽  
Bacillus Licheniformis ◽  
Thermal Inactivation ◽  
Soluble Solids ◽  
Effect Of Temperature ◽  
Pineapple Juice ◽  
Log Reduction ◽  
Different Temperatures ◽  
Soluble Solid ◽  
D Values

Bacillus subtilis and Bacillus licheniformis spores can survive processing temperatures used in the thermal processes of high-acid foods. Therefore, this study investigated the thermal inactivation of B. subtilis and B. licheniformis spores in pineapple juice at different temperatures (85–100°C) and soluble solids (SS, 11–30°Brix). The quality of juices and microbial loads after the thermal treatments during storage at 4 °C for 35 days was then checked. A linear decrease in D-value was observed with increasing temperature of treatment. Furthermore, the D-values determined in pineapple juice were: D90°C=13.2 ± 0.5 mins, D95°C = 6.8 ± 0.9 mins and D100°C = 2.1 ± 1.7 mins for B. subtilis spores, and D85°C = 16.6 ± 0.4 mins, D90°C = 7.6 ± 0.5 mins and D95°C = 3.6 ± 1.5 min, for B. licheniformis. Generally, the susceptibility of the bacteria to soluble solid change was affected by the interaction between temperature, SS and strain. In addition, pasteurization processes of ≥95°C for ≥33.8 mins was needed to ensure a recommended 5-log reduction of B. subtilis spores and limit vitamin C degradation of pineapple juice within three-week of storage at 4 °C.

scholarly journals Ecophysiology germination of Senna uniflora seeds: species for recovery degraded areas

2020 ◽  
Vol 42 ◽  
Author(s):  
Jullyanna Nair de Carvalho ◽  
Márkilla Zunete Beckmann Cavalcante ◽  
Pollyanna Aparecida de Carvalho ◽  
Daniel Salgado Pifano ◽  
Renato Garcia Rodrigues
Keyword(s):  
Effect Of Temperature ◽  
Tolerance Limits ◽  
Natural Conditions ◽  
Physical Dormancy ◽  
Adaptation Mechanisms ◽  
Temperature Regimes ◽  
Different Temperatures ◽  
Species Tolerance ◽  
C 30 ◽  
Osmotic Potentials

Abstract: Studies on seeds ecophysiology are important to understanding of adaptation mechanisms and of species´ tolerance limits to natural conditions, because determine the potential of use in recovery plans of degraded areas. The aim of this study was to characterize and assess the effect of different temperatures, methods of dormancy overcoming and water and salt stresses on the germination of Senna uniflora. Imbibition curve and germination assay were conducted to assess the effect of temperature regimes (20 °C, 25 °C, 30 °C, 35 °C, 40 °C and 20-30 °C), of methods of overcoming dormancy (without scarification, mechanical scarification, chemical scarification and thermal scarification) and of water and salt stresses at the osmotic potentials (0.0; -0.2; -0.4 and -0.8 MPa) . The assessed variables were germination, germination speed index and average germination time. Methods of mechanical and chemical scarification for 5, 15 and 30 min were efficient to overcome physical dormancy, especially on constant temperature regimes of 25 °C and 30 °C and alternated 20-30 °C. Submitted to conditions of water and salt stresses, seeds germination was reduced with the increase of the osmotic potential, being -0.8 MPa the germination minimum limit, in addition, seeds were more sensitive to water stress than to salt stress.

Sequential risk mitigation and the role of natural recovery in contaminated sediment projects

1998 ◽  
Vol 37 (6-7) ◽  
pp. 331-336 ◽  
Author(s):  
Stephen Garbaciak ◽  
Philip Spadaro ◽  
Todd Thornburg ◽  
Richard Fox
Keyword(s):  
Lower Cost ◽  
Risk Mitigation ◽  
Management Strategies ◽  
Source Control ◽  
Contaminated Sediment ◽  
Practical Observation ◽  
Ecosystem Recovery ◽  
Natural Recovery ◽  
Natural Processes

Sequential risk mitigation approaches the remediation of contaminated sediments in three phases designed to: (1) immediately reduce the ecological and human health risks associated with high levels of contamination, using methods such as the confinement or capping of high-risk materials; (2) reduce the risks associated with moderate levels of pollution to a minimum, on a less urgent schedule and at a lower cost; and (3) address areas of limited contamination through a combination of natural recovery and enhanced natural recovery (to aid or speed those natural processes). Natural recovery, the reduction of contaminant concentrations through natural processes, is based on the practical observation that overall ecosystem recovery appears to be largely a function of time. Sediment decomposition and the mixing of new and old sediments by bottom-dwelling organisms can both contribute to reduced contaminant concentrations. Knowledge of these processes--sediment decomposition, sediment mixing by bottom-dwelling organisms, and chemical residence time is critical in the development of appropriate ecosystem recovery and waste management strategies. Evaluations to support natural recovery predictions are designed to collect and evaluate information necessary to determine whether surface sediment chemical concentrations, with adequate source control, will reach the cleanup standards within a ten-year period.

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.

scholarly journals Effect of temperature, CO2 and O2 on motility and mobility of Anisakidae larvae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aiyan Guan ◽  
Inge Van Damme ◽  
Frank Devlieghere ◽  
Sarah Gabriël
Keyword(s):  
Enzymatic Digestion ◽  
Infected Fish ◽  
Effect Of Temperature ◽  
Video Recordings ◽  
Different Temperatures ◽  
Semi Solid ◽  
Zoonotic Parasites ◽  
The Impact ◽  
Phosphate Buffered Saline

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.

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