cold temperatures
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2022 ◽  
Vol 9 (12) ◽  
pp. 242-250
Author(s):  
Hefti Salis Yufidasari ◽  
Retno Tri Astuti ◽  
Eko Waluyo ◽  
Jekmal Malau

Lipases constitute as top three most important group of enzymes along with  carbohydrases and proteases, and are widely used in various industries. In particular, lipase that perform high activity at low temperatures, or referred as cold adapted lipase (CLPs) considered as attractive catalyst due to its activity at low temperature. This unique feature is the main advantage of cold adapted lipase utilization because it requires a low energy source that is correlated with lower production costs and energy. In addition, reactions occur in cold temperatures may result in better product quality. The purpose of this research was to perform screening and characterization of bacterial cold adapted lipase from seafood cold storage. Among 53 isolates, Kr_16_30, TI_37_14 and Kr_16_28 showed the highest activity with 4.12 U/mL; 3.87 U/mL and 3.21 U/mL, respectively. Isolates Kr_16_30 seemed to be typical cold adapted lipase with optimum temperature at 20°C and pH 7. Isolates Kr_16_28 performed highest lipolytic activity at 30°C while TI_37_14 suspected to be similar to typical mesophilic lipase with optimum temperature at 40°C. Species identification based on 16s rRDA sequencing revealed that isolates Kr_16 30 and Kr_16 28 are belong to genus Pseudomonas and Bacillus, repectively.


2022 ◽  
Author(s):  
Philipp Zschenderlein ◽  
Heini Wernli

Abstract. In early January 2021, Spain was affected by two extreme events – an unusually long cold spell and a heavy snowfall event associated with extratropical cyclone Filomena. For example, up to 50 cm of snow fell in Madrid and the surrounding areas in 4 days. Already during 9 days prior to the snowfall event, anomalously cold temperatures at 850 hPa and night frosts prevailed over large parts of Spain. During this period, anomalously cold and dry air was transported towards Spain from central Europe and even from the Barents Sea. The storm Filomena, which was responsible for major parts of the snowfall event, developed from a precursor low-pressure system over the central North Atlantic. Filomena intensified due to interaction with an upper-level potential vorticity (PV) trough, which was the result of anticyclonic wave breaking over Europe. In turn, this wave breaking was related to an intense surface anticyclone and upper-level ridge, whose formation was strongly influenced by a warm conveyor belt outflow of a cyclone off the coast of Newfoundland. The most intense snowfall occurred on 09 January and was associated with a sharp air mass boundary with an equivalent potential temperature difference at 850 hPa across Spain exceeding 20 K. Overall, the combination of pre-existing cold surface temperatures, the optimal position of the air mass boundary, and the dynamical forcing for ascent induced by Filomena and its associated upper-level trough were all essential – and in parts physically independent – ingredients for this extreme snowfall event to occur.


2022 ◽  
Vol 22 (1) ◽  
pp. 65-91
Author(s):  
Manuel Baumgartner ◽  
Christian Rolf ◽  
Jens-Uwe Grooß ◽  
Julia Schneider ◽  
Tobias Schorr ◽  
...  

Abstract. Laboratory measurements at the AIDA cloud chamber and airborne in situ observations suggest that the homogeneous freezing thresholds at low temperatures are possibly higher than expected from the so-called “Koop line”. This finding is of importance, because the ice onset relative humidity affects the cirrus cloud coverage and, at the very low temperatures of the tropical tropopause layer, together with the number of ice crystals also the transport of water vapor into the stratosphere. Both the appearance of cirrus clouds and the amount of stratospheric water feed back to the radiative budget of the atmosphere. In order to explore the enhanced ice onset humidities, we re-examine the entire homogeneous ice nucleation process, ice onset, and nucleated crystal numbers, by means of a two-moment microphysics scheme embedded in the trajectory-based model (CLaMS-Ice) as follows: the well-understood and described theoretical framework of homogeneous ice nucleation includes certain formulations of the water activity of the freezing aerosol particles and the saturation vapor pressure of water with respect to liquid water. However, different formulations are available for both parameters. Here, we present extensive sensitivity simulations testing the influence of three different formulations for the water activity and four for the water saturation on homogeneous ice nucleation. We found that the number of nucleated ice crystals is almost independent of these formulations but is instead sensitive to the size distribution of the freezing aerosol particles. The ice onset humidities, also depending on the particle size, are however significantly affected by the choices of the water activity and water saturation, in particular at cold temperatures ≲205 K. From the CLaMS-Ice sensitivity simulations, we here provide combinations of water saturation and water activity formulations suitable to reproduce the new, enhanced freezing line.


2021 ◽  
Vol 6 (2) ◽  
pp. 145-153
Author(s):  
Irwansyah ◽  
Balkhaya ◽  
Nuzuli Fitriadi ◽  
Herdi Susanto

The process of freezing fish always requires a cooler as a temporary storage place for fish. The ability of the storage to maintain cold temperatures is a serious problem to be considered so that the freshness of the fish can be maintained. Therefore, an appropriate technology is required to support the cold chain system so that fish quality can be maintained. The purpose of this study was to test the thermal conductivity of composite materials for fish storage insulation from a mixture of rice husks and polyurethane so that the price of the box can be reduced but still maintain the quality of the fish. The composition of the composite material was made with a volume ratio of 1:0.5, 1:1, 1:1.5, and 1:2. The thermal conductivity test of the material uses the ASTM E1225-99 standard. All test results were compared with 100% polyurethane material. The results of testing the thermal conductivity of 100% polyurethane material obtained 0.023 W/m.C. From all the test results, the material that is most likely to be applied to fish cooler box insulation is a 1:1 composition having a thermal conductivity value of 0.067W/m.C. Materials with this composition do not affect the expansion of the polyol and isocyanate reactions. This composition is the most economical to be used as insulation for fish storage boxes which can save the use of polyurethane by 50%.


Author(s):  
Aneta Teległów ◽  
Valerjan Romanovski ◽  
Beata Skowron ◽  
Dawid Mucha ◽  
Łukasz Tota ◽  
...  

Regular exposure to a cold factor—cold water swimming or ice swimming and cold air—results in an increased tolerance to cold due to numerous adaptive mechanisms in humans. Due to the lack of scientific reports on the effects of extremely low outdoor temperatures on the functioning of the human circulatory system, the aim of this study was to evaluate complete blood count and biochemical blood indices in multiple Guinness world record holder Valerjan Romanovski, who was exposed to extremely cold environment from −5 °C to −37 °C for 50 days in Rovaniemi (a city in northern Finland). Valerjan Romanovski proved that humans can function in extremely cold temperatures. Blood from the subject was collected before and after the expedition. The subject was found to have abnormalities for the following blood indices: testosterone increases by 60.14%, RBC decreases by 4.01%, HGB decreases by 3.47%, WBC decreases by 21.53%, neutrocytes decrease by 17.31%, PDW increases by 5.31%, AspAT increases by 52.81%, AlAT increase by 68.75%, CK increases by 8.61%, total cholesterol decreases by 5.88%, HDL increases by 28.18%. Percentage changes in other complete blood count and biochemical indices were within standard limits. Long-term exposure of the subject (50 days) to extreme cold stress had no noticeable negative effect on daily functioning.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Ahmad Haghani ◽  
Mehdi Jahangiri ◽  
Rouhollah Yadollahi Farsani ◽  
Ayoub Khosravi Farsani ◽  
Jalal Fazilatmanesh

Fluid-solid interaction phenomenon study is necessary for the analysis of several engineering systems such as structures and vessels that interact with wind and blood flow, respectively. In this study, the interactions between buoyancy-driven airflow and elastic baffle(s) inside a square enclosure were modeled numerically. While the two sidewalls of the enclosure were insulated, the lower and upper walls were kept at hot and cold temperatures, respectively. The heat transfer rate through the hot wall by calculating the Nusselt number and von Mises stress at the baffles’ root for various configurations of baffle(s) was considered. The domain was modeled in ANSYS Workbench, and the k-ε model was employed to solve the turbulent convective flow (Ra > 107). A two-way algorithm along with the finite element method was employed to simultaneously solve the equations governing the fluid flow and the solid phase. The dynamic mesh method was employed to account for the change in the location of the fluid domain at a new time step. The results show the elastic baffle, in comparison to solid baffle, intensifies the heat transfer rate by 15%. The results also indicate that the Nusselt number in the single-baffle case is higher than in double-baffle cases. The fact that the amount of von Mises is a function of the baffles’ configuration is another point obtained from the results. It was found that the von Mises stress at the baffles’ root represents more unsteady fluctuations in the asymmetric case, while it approaches a constant value in the symmetric case.


Metabolites ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Jiayuan Liang ◽  
Wenwen Luo ◽  
Kefu Yu ◽  
Yongqian Xu ◽  
Jinni Chen ◽  
...  

Global climate change has resulted in large-scale coral reef decline worldwide, for which the ocean warming has paid more attention. Coral is a typical mutually beneficial symbiotic organism with diverse symbiotic microorganisms, which maintain the stability of physiological functions. This study compared the responses of symbiotic microorganisms and host metabolism in a common coral species, Pavona minuta, under indoor simulated thermal and cold temperatures. The results showed that abnormal temperature stresses had unfavorable impact on the phenotypes of corals, resulting in bleaching and color change. The compositions of symbiotic bacteria and dinoflagellate communities only presented tiny changes under temperature stresses. However, some rare symbiotic members have been showed to be significantly influenced by water temperatures. Finally, by using ultra-performance liquid chromatography tandem mass spectrometry (UPLC–MS) method, we found that different temperature stresses had very different impacts on the metabolism of coral holobiont. The thermal and cold stresses induced the decrease of anti-oxidation metabolites, several monogalactosyldiacylglycerols (MGDGs), and the increase of lipotoxic metabolite, 10-oxo-nonadecanoic acid, in the coral holobiont, respectively. Our study indicated the response patterns of symbiotic microorganisms and host metabolism in coral to the thermal and cold stresses, providing theoretical data for the adaptation and evolution of coral to a different climate in the future.


2021 ◽  
Vol 16 (6) ◽  
pp. 691-699
Author(s):  
Purnama Ningsih ◽  
Sitti Rahmawati ◽  
Ni Made Nila Santi ◽  
Suherman ◽  
Anang Wahid M. Diah

This study aims to determine the physical and chemical characteristics of the edible film of jackfruit seed starch (Artocarpus heterophyllus) added with antioxidant rosella flower extract (Hibiscus sabdariffa). The type of plasticizer used is glycerol. The best treatment in this study was the jackfruit seed edible film with the addition of rosella flower extract 3% (v/v) with the results obtained respectively for a thickness of 0.09 mm, tensile strength 0.003332 N/mm2, elongation percentage 126.36%, elasticity 0.002637 Kgf/mm2, pH 6.122, water absorption 61.67%, solubility 40%, water vapor transmission speed 0.6714 gram/hour m2, FTIR test results show that the process of making edible film in this research is the mixing process Physics, the shelf life of edible film at room temperature is 6 days and at cold temperatures is 8 days, and has antioxidant activity with an IC50 value 219.948 ppm. The addition of rosella flower extract enhances another benefit of edible film which functions as a food protector from the oxidation process (antioxidant).


2021 ◽  
Author(s):  
Michael Tong ◽  
Berhanu Wondmagegn ◽  
Jianjun Xiang ◽  
Susan Williams ◽  
Alana Hansen ◽  
...  

Abstract Background: The association between temperatures and respiratory diseases has been extensively reported. However, the associated healthcare costs and attributable fractions due to temperature have scarcely been explored. The aims of this study were to estimate respiratory disease hospitalization costs attributable to non-optimum ambient temperature, to quantify the attributable fraction from cold and hot temperatures, and to estimate the future hospitalization costs in two Australian cities. Methods: The associations between daily hospitalization costs for respiratory diseases and temperatures in Sydney and Perth over the study period of 2010-2016 were analyzed using distributed lag non-linear models. Future hospitalization costs for respiratory diseases were estimated based on three predicted climate change scenarios - RCP2.6, RCP4.5 and RCP8.5. Results: The estimated respiratory disease hospitalization costs attributable to non-optimum ambient temperatures increased from 493.2 million Australian dollars (AUD) in 2010s to more than 700 million AUD in 2050s in Sydney, and from 98.0 million AUD to about 150 million AUD during the same period in Perth, in large part due to population growth. In the context of climate change, the current cold attributable fraction in Sydney (23.7%) and Perth (11.2%) is estimated to decline by the middle of this century to (18.1-20.1%) and (5.1-6.6%) respectively, while the heat-attributable fraction for respiratory disease is expected to gradually increase from 2.6% up to 5.5% in Perth. Conclusions: This study found both cold and hot temperatures increased the overall hospitalization costs for respiratory diseases in two major Australian cities, although the attributable fractions varied. The largest contributor was cold temperatures. While respiratory disease hospitalization costs will increase in the future, climate change will result in a decrease in the cold attributable fraction and an increase in the heat attributable fraction, depending on the location.


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