Effects of temperature on the macromolecular composition and fine structure of psychrophilic Arthrobacter species

1977 ◽  
Vol 23 (3) ◽  
pp. 357-362 ◽  
Author(s):  
Anne-Monique Gounot ◽  
Thomas J. Novitsky ◽  
Donn J. Kushner
Keyword(s):  
Fine Structure ◽  
Single Cells ◽  
Cell Mass ◽  
Viable Cell ◽  
Psychrophilic Bacterium ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Lower Temperature ◽  
Arthrobacter Species ◽  
Macromolecular Composition

A facultatively psychrophilic bacterium, Arthrobacter SI 55, grows at 20 °C, but growth, as measured by increase of viable cell count, is inhibited at 32 °C. Corresponding temperatures for an obligate psychrophile, Arthrobacter glacialis SI 137, are 10 °C and 19–20 °C. At the higher temperatures for each organism increases of cell mass, as measured by turbidity and of DNA, RNA, and protein, were not inhibited. At the upper temperatures, fewer septa were formed in Arthrobacter SI 55, and cells appeared as distorted filaments with irregular branches. Arthrobacter glacialis grew as single cells at the lower temperature, but as clumps of coccoid cells with well marked septa at the higher temperature. It appears that in Arthrobacter SI 55 septum formation may be inhibited at the higher temperature. In contrast, in A. glacialis septation occurs but the cells do not separate.

The Self-Decay Characteristics of Chlorine Dioxide in Water

2012 ◽  
Vol 610-613 ◽  
pp. 296-299
Author(s):  
Xin Jie Li ◽  
Dan Nan Jiang ◽  
Yue Jun Zhang
Keyword(s):  
Rate Constants ◽  
Tap Water ◽  
Pure Water ◽  
Decay Behaviour ◽  
Increase With Increase ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Temperature Water

In order to learn the ClO2 decay behaviour in tap water, the kinetics of ClO2 decay in pure water was studied. Under the conditions of tap water treatment and keeping away from light, the effects of temperature and pH on ClO2 degradation were investigated. The results show that the ClO2 decay reaction in pure water is the first-order with respect to ClO2, the decay rate constants increase with increase in temperature or pH. At pH=6.87, the rate constants are 0.012h-1(15°C), 0.017h-1(25°C), 0.023h-1(35°C), and 0.029h-1(45°C), respectively. At 25°C, the rate constants are 0.0083h-1(pH=4.5), 0.0111h-1(pH=5.5), 0.0143h-1(pH=6.5), 0.0222h-1(pH=7.5), and 0.0351h-1(pH=8.5), respectively. The experimental data prove that ClO2 is more stable in acidic or lower temperature water than in neutral, alkalescent, or higher temperature water.

scholarly journals Temperature-dependent competitive outcomes between the fruit flies Drosophila santomea and D. yakuba

2020 ◽  
Author(s):  
Aaron A. Comeault ◽  
Daniel R. Matute
Keyword(s):  
Indirect Effects ◽  
Competitive Exclusion ◽  
Thermal Environment ◽  
Species Distributions ◽  
Direct Effects ◽  
Temperature Dependent ◽  
Competitive Outcomes ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Lower Temperature

AbstractChanges in temperature associated with climate change can alter species’ distributions, drive adaptive evolution, and, in some cases, cause extinction. Research has tended to focus on the direct effects of temperature, but changes in temperature can also have indirect effects on populations and species. Here we test whether temperature can indirectly affect the fitness of Drosophila santomea and D. yakuba by altering interspecific competitive outcomes. We show that, when raised in isolation, both D. santomea and D. yakuba show maximal performance at temperatures near 22°C. However, when raised together, D. santomea outcompetes D. yakuba at a lower temperature (18°C), while D. yakuba outcompetes D. santomea at a higher temperature (25°C). We then use a ‘coexistence’ experiment to show that D. santomea is rapidly (within 8 generations) extirpated when maintained with D. yakuba at 25°C. By contrast, D. santomea remains as (or more) abundant than D. yakuba over the course of ~10 generations when maintained at 18°C. Our results provide an example of how the thermal environment can indirectly affect interspecific competitive outcomes and suggest that changes in the competitive advantage of species can lead to some species becoming more prone to extinction by competitive exclusion.

Environmental Effects on the Mechanical Properties of Small Structures

2016 ◽  
Author(s):  
Seyed Allameh ◽  
Jennifer Wardlow
Keyword(s):  
Mechanical Properties ◽  
Environmental Factors ◽  
Aluminum Foam ◽  
Microelectromechanical Systems ◽  
Tensile Behavior ◽  
Microtensile Testing ◽  
Higher Temperature ◽  
Properties Of Materials ◽  
Effects Of Temperature ◽  
Lower Temperature

Size-effect is known to influence the mechanical properties of materials at micro- and nanoscales. Mechanisms of fracture and failure are often affected by environmental factors such as temperature and humidity. The latter is postulated to cause stress corrosion cracking in metallic and ceramic Microelectromechanical Systems (MEMS) components. A recently-developed hybrid microtester enclosed in an environmentally-controlled chamber was used to study the effects of temperature on the mechanical properties of small structures. MEMS-scale specimens, prepared from aluminum foam struts as well as covetic aluminum were tested in microtensile testing. Results of these micromechanical tests show that the tensile behavior of Al struts are similar at temperatures of 11 and 42 °C. Further, covetic Al samples show a higher strength at a lower temperature (15 °C), but higher ductility at a higher temperature (44 °C).

Studies on the Toxicity of insecticide Films. II.—Effect of Temperature on the Toxicity of DDT Films

1949 ◽  
Vol 40 (2) ◽  
pp. 239-265 ◽  
Author(s):  
S. Pradhan
Keyword(s):  
Effect Of Temperature ◽  
Two Factors ◽  
Different Temperatures ◽  
Insecticidal Action ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Insect Activity ◽  
Lower Temperature ◽  
Toxicity Relationship ◽  
The Relationship

1. A series of exploratory experiments on the relationship between temperature and toxicity of DDT films to adults of Tribolium castaneum, and larvae of Plutella maculipennis, are described. The main conclusions with T. castaneum are:—(a) When the insects are continuously kept on the film at different temperatures there is a higher kill at higher temperatures.(b) When the insects are exposed to the film for about 24 hours at the same temperature and then kept away from it at different temperatures there is a higher kill at the lower temperature.(c) When the insects are kept on the film at different temperatures for about 24 hours and then kept away from the film for reaction at the same temperature, there is a higher kill in those kept on the film at the higher temperature.(a) and (b) above apply equally to larvae of P. maculipennis but (c) is reversed. The probable cause of this reversal appears to be the observed fact that at higher temperatures these larvae cover the film with much more silk thread and thus avoid contact to a greater extent than at lower temperatures.2. A review of literature, in the light of the conclusions arrived at, indicate that many of the observations made upon the temperature-toxicity relationship can be accounted for by the following generalisations:—(a) Insect resistance to poisons changes with temperature as do its other vital activities, increasing up to a critical degree and afterwards declining.(b) The amount of poison reaching the site of action in unit time also varies with the temperature, generally but not always, increasing with its rise. Insect activity, especially locomotor and respiratory, may play an important part in these effects.(c) The apparent effects of temperature on insecticidal action is the combination of these two factors, namely, resistance and pick-up.

scholarly journals Achieving Efficient and Stable Deammonification at LowTemperatures—Experimental and Modeling Studies

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3961
Author(s):  
Hussein Al-Hazmi ◽  
Xi Lu ◽  
Dominika Grubba ◽  
Joanna Majtacz ◽  
Przemysław Kowal ◽  
...  
Keyword(s):  
Sequencing Batch Reactor ◽  
Energy Savings ◽  
Batch Reactor ◽  
Phase Changes ◽  
Intermittent Aeration ◽  
Short Term ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
The Mathematical Model ◽  
Positive Effect

The short-term effects of temperature on deammonification sludge were evaluated in a laboratory-scale sequencing batch reactor (SBR). Mathematical modeling was used for further evaluations of different intermittent aeration strategies for achieving high and stable deammonification performance at decreasing temperatures. As for the biomass cultivated at high temperatures (e.g., 30 °C), a higher temperature dependency (the adjusted Arrhenius coefficient θ for 11–17 °C = 1.71 vs. θ for 17–30 °C = 1.12) on the specific anammox growth rates was found at lower temperatures (11–17 °C) in comparison with higher temperatures (17–30 °C). Further evaluations of recovering the nitrogen removal efficiency at decreasing temperatures with the mathematical model by modifying the intermittent aeration strategies (aeration frequency (F) and the ratio (R) between non-aerated (non-aer) phase and aerated (aer) phase durations) indicated that intermittent aeration with a prolonged non-aerated phase (e.g., R ≥ 4 regardless of F value) would help to maintain high and stable deammonification performance (~80%) at decreasing temperatures (14–22 °C). Extending the non-aerated phases (increasing R) and reducing the frequency (F) of off/on phase changes have a positive effect on increasing energy savings, leading to increasing interest in this method.

scholarly journals Sprouting of Sorghum (Sorghum bicolor [L.] Moench): Effect of Drying Treatment on Protein and Starch Features

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 407 ◽  
Author(s):  
Mia Marchini ◽  
Alessandra Marti ◽  
Claudia Folli ◽  
Barbara Prandi ◽  
Tommaso Ganino ◽  
...  
Keyword(s):  
Food Production ◽  
Cost Effective ◽  
High Exposure ◽  
Effective Technology ◽  
Drying Treatment ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The One ◽  
Drying Conditions ◽  
Sorghum Bicolor L

The nutritional and physicochemical properties of sorghum proteins and starch make the use of this cereal for food production challenging. Sprouting is a cost-effective technology to improve the nutritional and functional profile of grains. Two drying treatments were used after sorghum sprouting to investigate whether the drying phase could improve the protein and starch functionalities. Results showed that the drying treatment at lower temperature/longer time (40 °C for 12 h) extended the enzymatic activity that started during sprouting compared to the one performed at higher temperature/shorter time (50 °C for 6 h). An increased protein hydrolysis and water- and oil-holding capacity were found in the flour obtained by the former treatment. Higher protein matrix hydrolysis caused high exposure of starch to enzymes, thus increasing its digestibility, while worsening the technological functionality. Overall, modulating drying conditions could represent a further way, in addition to sprouting, to improve sorghum flour’s nutritional profile.

scholarly journals Lower Temperatures Exacerbate NLRP3 Inflammasome Activation by Promoting Monosodium Urate Crystallization, Causing Gout

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1919
Author(s):  
Huijeong Ahn ◽  
Gilyoung Lee ◽  
Geun-Shik Lee
Keyword(s):  
Environmental Factor ◽  
Nlrp3 Inflammasome ◽  
Inflammasome Activation ◽  
Optimal Temperature ◽  
Monosodium Urate ◽  
Nlrp3 Inflammasome Activation ◽  
Hyperthermia Therapy ◽  
Effects Of Temperature ◽  
Lower Temperature ◽  
Msu Crystals

Gout is a recurrent and chronic form of arthritis caused by the deposition of monosodium urate (MSU) crystals in the joints. Macrophages intake MSU crystals, the trigger for NLRP3 inflammasome activation, which leads to the release of interleukin (IL)-1β and results in the flaring of gout. The effects of temperature, an environmental factor for MSU crystallization, on IL-1β secretion have not been well studied. This study examined the effects of temperature on inflammasome activation. Specific triggers activated canonical inflammasomes (NLRP3, NLRC4, and AIM2) in murine macrophages at various temperatures (25, 33, 37, 39, and 42 °C). The maturation of IL-1β and caspase-1 was measured as an indicator for inflammasome activation. As expected, the optimal temperature of inflammasome activation was 37 °C. The MSU crystal-mediated activation of inflammasome increased at temperatures lower than 37 °C and decreased at higher temperatures. MSU crystals at lower temperatures enhanced IL-1β secretion via the NLRP3 inflammasome pathway. A lower temperature promoted the formation of MSU crystals without changing phagocytosis. Overall, lower temperatures form more MSU crystals and enhance NLRP3 inflammasome activation. In light of these findings, it is possible that hyperthermia therapy may reduce gout flaring.

MICROSTRUCTURAL EVOLUTION OF Al-Cu-Mg-Ag ALLOY WITH TRACE Zr ADDITION DURING TWO-STEP HOMOGENIZATION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 855-862 ◽  
Author(s):  
FEIYUE MA ◽  
ZHIYI LIU
Keyword(s):  
Melting Point ◽  
Grain Boundaries ◽  
Microstructural Evolution ◽  
Cast Alloy ◽  
Scanning Calorimetry ◽  
Zr Addition ◽  
Homogenization Time ◽  
The Matrix ◽  
Higher Temperature ◽  
Lower Temperature

The microstructural evolution in an Al - Cu - Mg - Ag alloy with trace Zr addition during homogenization treatment was characterized by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS). It was shown that the low-melting-point phase segregating toward grain boundaries is Al 2 Cu , with a melting point of 523.52°C. A two-step homogenization process was employed to optimize the microstructure of the as-cast alloy, during which the alloy was first homogenized at a lower temperature, then at a higher temperature. After homogenized at 420°C for 6 h, Al 3 Zr particles were finely formed in the matrix. After that, when the alloy was homogenized at an elevated temperature for a longer time, i.e., 515°C for 24 h, most of the precipates at the grain boundaries were removed. Furthermore, the dispersive Al 3 Zr precipitates were retained, without coarsening greatly in the final homogenization step. A kinetics model is employed to predict the optimal homogenization time at a given temperature theoretically, and it confirms the result in present study, which is 420°C/6h+515°C/24h.

scholarly journals Research on the Static Recrystallization and Precipitation Behaviors of a V-N Microalloyed Steel

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Baochun Zhao ◽  
Tan Zhao ◽  
Guiyan Li ◽  
Qiang Lu
Keyword(s):  
Static Recrystallization ◽  
Microalloyed Steel ◽  
Time Interval ◽  
Main Role ◽  
Recrystallization Process ◽  
Compression Tests ◽  
Double Compression ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Temperature Strain

Double compression tests were performed on a Gleeble-3800 thermomechanical simulator to study the softening behaviors of deformed austenite in a V-N microalloyed steel. The static recrystallization volume fractions were calculated by stress offset method, and the kinetic model of static recrystallization was constructed. The effects of temperature, strain, and time interval on the softening behaviors were analyzed, and the interactions between precipitation and recrystallization were discussed. The results show that the softening behaviors of the deformed austenite at lower temperature or higher temperature are markedly different. At the temperature of 850°C or 800°C, pinning effects of the precipitates play the main role, and the recrystallization process is inhibited, which leads to the formation of plateaus in the softening curves. An increase in strain promotes the precipitation and recrystallization processes while reduces the inhibition effect of precipitation on recrystallization as well.

Effects of Sr Addition on Mechanical Properties and Microstructure of Mg-6Al Magnesium Alloy

2011 ◽  
Vol 686 ◽  
pp. 120-124
Author(s):  
Jin Ping Fan ◽  
She Bin Wang ◽  
Bing She Xu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Strengthening Mechanism ◽  
Microstructure And Mechanical Properties ◽  
Higher Temperature ◽  
Lower Temperature

The effects of Sr addition on the mechanical properties and microstructure of Mg-6Al mag- nesium alloy both at 25 °C and at 175 °C were investigated by means of OM, SEM and EDS and XRD. Upon the Sr addition of 2%, the tensile strength was increased by 7.2% to 184.4MPa at 25 °C, while it was increased by 30% to 155.4MPa at 175 °C. The strengthening mechanism of Mg-6Al-xSr at lower temperature (25 °C) was different from that at higher temperature (175°C). The results show that the addition of strontium effectively improved the microstructure and mechanical properties of magnesium alloy.

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