Specific Effects Of Temperature Research Articles

A comparative study of tissue protein synthesis rates in an Antarctic, Harpagifer antarcticus and a temperate, Lipophrys pholis teleost

The affect of temperature on tissue protein synthesis rates has been reported in temperate and tropical, but not Antarctic fishes. Previous studies have generally demonstrated low growth rates in Antarctic fish species in comparison to temperate relatives and elevated levels of protein turnover. This study investigates how low temperatures effect tissue protein synthesis and hence tissue growth in a polar fish species. Groups of Antarctic, Harpagifer antarcticus and temperate, Lipophrys pholis, were acclimated to a range of overlapping water temperatures and protein synthesis was measure in white muscle (WM), liver and gastrointestinal tract (GIT). WM protein synthesis rates increased linearly with temperature in both species (H. antarcticus 0.16–0.23%.d−1, L. pholis, 0.31–0.76%.d−1), while liver (H. antarcticus 0.24–0.27%.d−1, L. pholis, 0.44–1.03%.d−1) and GIT were unaffected by temperature in H. antarcticus but increased non-linearly in L.pholis (H. antarcticus 0.22–0.26%.d−1, L. pholis, 0.40–0.86%.d−1). RNA to protein ratios were unaffected by temperature in H. antarcticus but increased weakly, in L.pholis WM and liver. In L.pholis, RNA translational efficiency increased significantly with temperature in all tissues, but only in liver in H. antarcticus. At the overlapping temperature of 3 °C, protein synthesis (WM 26%, Liver, 39%, GIT, 35%) and RNA translational efficiency (WM 273%, Liver, 271%, GIT, 300%) were significantly lower in H. antarcticus than L.pholis, while RNA to protein ratios were significantly higher (WM 270%, Liver 170%, GIT 186%). Tissue specific effects of temperature are detectable in both species. This study provides the first evidence, that tissue protein synthesis rates are constrained in Antarctic fishes.

Influence of temperature on the process of preparing homogenised magnesium-zinc alloy spherical powders using the relative vacuum method

The production of magnesium-zinc (Mg-Zn) alloy spherical powders is complex and expensive. As they have extensive applications in a wide variety of fields including military manufacturing, aerospace, and biomedicine, there is an urgent need to explore new production processes for Mg-Zn alloy spherical powders. In this study, 5 wt% homogenised Mg-Zn alloy spherical powder was prepared using the relative vacuum method. The effects of the insulation time, maximum temperature, and heating rate on the morphology, size distribution, and particle size of the Mg-Zn alloy spherical powder were investigated. The results indicated that the insulation time had the greatest influence on the particle size of the spherical powder, whereas the maximum temperature and heating rate had significant impacts on the alloy composition. When the insulation time was 10 min the maximum temperature was 1150 °Cand the heating rate was 15 min, the prepared Mg-Zn alloy spherical powder exhibited a full morphology without satellite particles, uniform composition, narrow size distribution, and a volume median diameter (VMD) of 17.62 μm. The research findings provide a new production process for Mg-Zn alloy spherical powders and establish a foundation for studying the specific effects of temperature on the production of Mg-Zn alloy spherical powders using the relative vacuum method.

Impacts of Temperature on the Growth, Feed Utilization, Stress, and Hemato-Immune Responses of Cherry Salmon (Oncorhynchus masou).

Cherry salmon (Oncorhynchus masou) hold commercial value in aquaculture, and there is a need for controlled laboratory studies to isolate the specific effects of temperature on their growth, feeding, and well-being. We examined the effects of different temperatures (10 °C, 14 °C, 18 °C, and 22 °C) on juvenile cherry salmon (average mass 29.1 g) in triplicate tanks per treatment over eight weeks. The key parameters assessed included growth rate, feed efficiency, stress response, and hemato-immune responses. Our objectives were to determine the most and less favorable temperatures among the four designated temperatures and to assess the adverse effects associated with these less favorable temperatures. The results showed that body weight, growth rates, feed intake, and feed efficiency were significantly higher at 10 °C and 14 °C compared to 18 °C and 22 °C. Reduced appetite and feeding response were observed at 22 °C. Red blood cell parameters were significantly lower at 22 °C. At 10 °C, the results showed significantly increased plasma cortisol levels, gill Na+/K+-ATPase activity, body silvering, and decreased condition factors, suggesting potential smoltification. The potential smoltification decreased with increasing temperatures and disappeared at 22 °C. Furthermore, the plasma lysozyme concentrations significantly increased at 18 °C and 22 °C. In conclusion, our study identifies 10 °C and 14 °C as the temperatures most conducive to growth and feed performance in juvenile cherry salmon under these experimental conditions. However, temperatures of 22 °C or higher should be avoided to prevent compromised feeding, reduced health, disturbed immune responses, impaired growth, and feed performance.

Measurements and interpretation of crude Oil-Water/Brine dynamic interfacial tension at subsurface representative conditions

Interfacial tensions (IFTs) between crude oil and water or brine systems are critically important in many processes. Exhibited dynamic behavior often remains poorly studied and requires in-depth analysis. In this study, 27 series of dynamic IFT measurements were conducted for three different crude oils in combination with three different aqueous phases (pure water and two synthetic reservoir brines) at temperatures of 298.15, 343.15 and 393.15 K and pressures up to 30 MPa. This study provides a large database of crude oil-water/brine IFTs encompassing reservoir conditions of temperature and pressure. Specific effects of temperature, pressure, and fluid composition on the crude oil-water and oil-brine IFTs were evaluated. The dynamic evolution of the IFT between the crude oils and aqueous phases was categorized according to typical relationships observed. The most commonly observed evolution was an initial rapid decline in IFT, over a period of 100 to 1,000 s, followed by levelling off at a nearly-constant long-term value. However, in certain cases, the initial rapid decline was followed by a broad minimum and a subsequent slow increase towards a nearly-steady long-time value. In either case, the initial decline is described by a simple model based on diffusion of surface-active components in the oil and their subsequent adsorption at the interface. The longer-term behavior may be further attributed to a combination of saturation, rearrangement and dissolution of the surface-active components.

Temperature effect on the material removal mechanism of soft-brittle crystals at nano/micron scale

Soft-brittle crystals, e.g. KH2PO4 (KDP), are difficult-to-cut due to their high brittleness which can easily generate crack during the machining process. The conventional method to machine this kind of material is by inducing ductile cutting mechanism at room temperature with ultra-precision machining, which can only remove materials at nanoscale level and hence yields very low material removal rate. While some thermal-assisted processes have been recently attempted to improve the machinability of some difficult-to-cut materials, e.g. ceramics, there is no systematic understanding of the temperature effect on material removal mechanism of soft-brittle KDP crystals yet. In this work, the temperature effect on the material removal mechanism has been investigated for the first time using nano-scratch technique. While a decreased hardness and elastic modulus have been observed with the increase of temperature, an increase of fracture toughness has been revealed with a contradictory tendency, indicating a higher capacity of plastic deformation at elevated temperature. In contrast to the almost totally brittle scratch at room temperature (RT) caused by crack propagation and edge chipping, the scratch at 170 °C can achieve more ductile-regime surfaces with a larger critical undeformed cutting depth (3.61 μm), e.g. a significant increase of 8.60 times compared with that at RT (0.42 μm). Moreover, the TEM analysis on the subsurface microstructures shows that a great number of nano grits was generated in the subsurface at RT as the result of crack propagation and interaction, while at elevated temperature some crystallographic lattice misaligned structures (LMS) and nano crystals have been brought about due to the nucleation and evolution of thermal-activated dislocations, which explains the higher plasticity of KDP at elevated temperature. The results present in this paper are of great significance for understanding the specific temperature effect on the brittle-to-ductile transition of the cutting mechanism for future designing thermal-involved processes to machine soft-brittle materials.

Carbon quality and nutrient status drive the temperature sensitivity of organic matter decomposition in subtropical peat soils

Estimates of gaseous carbon (C) fluxes in wetlands are heavily based on temperature. However, isolating specific effects of temperature on anaerobic C processing from other controls (C quality and nutrients) has proven difficult. Here, we test the hypothesis that temperature sensitivity of soil organic matter (SOM) decomposition is more influenced by C quality than nutrient availability in subtropical freshwater, sawgrass (Cladium jamaicense)-based peats. Carbon age (characterized by depth: 0–10 and 10–20 cm) was used as a surrogate of C quality while two sites were selected with contrasting levels of nutrient (P) availability. In anaerobic laboratory incubations temperature was increased in 5 °C steps to assess the proportion of C available at a given temperature (i.e. thermo-labile C) as productions of gaseous (CO2 and CH4) and dissolved organic C (DOC) fractions. Thermo-labile C increased 3.1–3.6 times from 15 °C to 30 °C in all soils. Disproportionate increase in the production of gaseous forms versus DOC as well as CH4:CO2 was observed with warming. Observed Q10 values followed the trend of CH4 (~14) ≫ CO2 (~2.5) > DOC (~1.7) and temperature sensitivity was more dependent on C quality than nutrient availability over the entire temperature range. Spectral analysis indicated more bio-available DOC production at higher temperature. Regression analysis also indicated that C quality primarily influenced SOM decomposition at lower temperature, while at higher temperature nutrient limitation dominantly controlled SOM decomposition. These findings confirm the role of C quality in temperature sensitivity of warm peat soils, but also indicate an increased importance of nutrient limitation at higher temperature.

Temperature effects in static and dynamic polarizabilities from distinct generalized gradient approximation exchange-correlation functionals

To demonstrate that there are specific temperature effects in the description of static and dynamic polarizabilities which arise from generalized gradient approximation exchange-correlation functionals that obey distinctive asymptotic constraints, we present calculations for a test set of small molecules, at the experimental geometry, at the optimized ground-state geometry, and at the Born-Oppenheimer molecular dynamics geometries that arise from simulating a temperature of 300K. The results indicate that a functional with the correct asymptotic potential (CAP) provides a better description at room temperature than does a GGA functional with an exponentially decaying exchange potential such as PBE.

Gene expression analysis at the onset of sex differentiation in turbot (Scophthalmus maximus).

BackgroundControlling sex ratios is essential for the aquaculture industry, especially in those species with sex dimorphism for relevant productive traits, hence the importance of knowing how the sexual phenotype is established in fish. Turbot, a very important fish for the aquaculture industry in Europe, shows one of the largest sexual growth dimorphisms amongst marine cultured species, being all-female stocks a desirable goal for the industry. Although important knowledge has been achieved on the genetic basis of sex determination (SD) in this species, the master SD gene remains unknown and precise information on gene expression at the critical stage of sex differentiation is lacking. In the present work, we examined the expression profiles of 29 relevant genes related to sex differentiation, from 60 up to 135 days post fertilization (dpf), when gonads are differentiating. We also considered the influence of three temperature regimes on sex differentiation.ResultsThe first sex-related differences in molecular markers could be observed at 90 days post fertilization (dpf) and so we have called that time the onset of sex differentiation. Three genes were the first to show differential expression between males and females and also allowed us to sex turbot accurately at the onset of sex differentiation (90 dpf): cyp19a1a, amh and vasa. The expression of genes related to primordial germ cells (vasa, gsdf, tdrd1) started to increase between 75–90 dpf and vasa and tdrd1 later presented higher expression in females (90-105 dpf). Two genes placed on the SD region of turbot (sox2, fxr1) did not show any expression pattern suggestive of a sex determining function. We also detected changes in the expression levels of several genes (ctnnb1, cyp11a, dmrt2 or sox6) depending on culture temperature.ConclusionOur results enabled us to identify the first sex-associated genetic cues (cyp19a1a, vasa and amh) at the initial stages of gonad development in turbot (90 dpf) and to accurately sex turbot at this age, establishing the correspondence between gene expression profiles and histological sex. Furthermore, we profiled several genes involved in sex differentiation and found specific temperature effects on their expression.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-2142-8) contains supplementary material, which is available to authorized users.

Thermodynamics of Ammonia and Ammonium Ion at the Aqueous Solution–Air Interfaces

Ammonia (NH3) and ammonium ion (NH4+) are two main pollutants of Earth’s surface water system. Toward an understanding of the microscopic structures and thermodynamic properties of NH3 and NH4+ (along with halogen anion Cl–, Br–, or I–) at the aqueous solution–air interfaces, all-atom molecular dynamics simulations are performed with different solute concentrations and at various temperatures. The surface propensities of NH3, Br–, and I– species are predicted, while the NH4+ is repelled from the interface. The solute concentration strongly influences the spatial distributions of NH3, Cl–, Br–, and I– near the interface; moreover, the specific temperature effects on the surface charge, molecular orientation, and surface tension are demonstrated.

Temperature and pressure effects on positive streamers in air

In this paper we investigate temperature and pressure effects on the properties of a positive pulsed streamer plasma. We use a corona plasma setup in which we vary the temperature between 303 and 773 K at atmospheric pressure and the pressure between 37.9 and 100 kPa at room temperature to achieve the same neutral gas density and compare electrical and optical (ICCD imaging) measurements carried out in both experiments.From the measurements we found that the dissipated plasma energy and the average streamer propagation velocity are both higher for the temperature experiments at the same neutral gas densities as in the pressure experiments. This suggests the existence of a specific temperature effect. A possible explanation for this effect is a higher streamer conductivity at high temperatures, as was previously found in the literature.

Congeneric Amphipods Show Differing Abilities to Maintain Metabolic Rates with Latitude

Metabolic variability across latitudinal populations of gammarid amphipods was examined in the summer by determining whole-animal rates of oxygen uptake (M(o)₂) in four species with overlapping distribution patterns in the northeast Atlantic and Arctic oceans. Comparisons were made between an arctic/boreal species, Gammarus setosus, a subarctic/boreal species, Gammarus oceanicus, a boreal/temperate species, Gammarus duebeni duebeni, and a temperate species, Gammarus locusta. Measurements included acclimatized M(o)₂ in all four species and M(o)₂ after acclimation to 10°C in two populations of G. oceanicus and G. locusta. In G. oceanicus, acclimatized M(o)₂ declined with latitude (13° to 5°C) so that metabolic rates were lower in subarctic (79°N) relative to temperate (58°N) populations and similar to the values in G. setosus at 79°N. Consequently, there was no evidence for metabolic rate compensation in the colder-water, high-latitude populations in the summer. Further examination of the specific effects of temperature revealed similarities in M(o)₂ between populations of G. oceanicus acclimated at 10°C and similarities in thermal sensitivity (Q(10)) and activation energies (E(a)) on exposure to acute temperature change. In sharp contrast, there was no variation in summer acclimatized M(o)₂ with latitude in either G. d. duebeni between 48° and 70°N or G. locusta between 38° and 53°N. Instead, the two species maintained relatively high metabolic rates across latitudes, which were associated in G. locusta with differences in M(o)₂ and with Q(10) and E(a) values in amphipods acclimated at 10°C. The ability to compensate metabolic rate with latitude in the summer suggests greater metabolic flexibility, which predicts a greater capacity for survival during climate change of the temperate/boreal over the subarctic and arctic gammarid species.

Phase behavior of Phytantriol/water bicontinuous cubic Pn3m cubosomes stabilized by Laponite disc-like particles

The present article reports on the specific effects of temperature on Phytantriol-based cubosomes stabilized by inorganic stabilizers as opposed to organic stabilizers. The ability of Laponite to stabilize Phytantriol-based parent bulk phase is first demonstrated. The sub-micron-sized Laponite-stabilized particles were found to be both physically and chemically stable over time. The temperature-induced behavior, both in heating and cooling directions, of these lipid-based cubosomes has been investigated and compared with their polymer-stabilized counterparts (Pluronic F127). This allows us to extract the particular influence of each stabilizer. Whereas an increased hydration of the cubic structure was evidenced at high pH values, this effect was eliminated to compare the specific influence of both stabilizers on these Phytantriol-based cubosomes. Evidence of differences in the relaxation rates of the internal structures with temperature was found for the two stabilizers, in particular in the cooling direction whilst in the heating direction the two stabilizers could be considered as undisruptive. The origin of this difference is discussed.

Development and growth of two Lesquerella species grown under different temperatures during the reproductive period

The genus Lesquerella is a promising source of hydroxy fatty acids (HFA). Several species such as Lesquerella fendleri and Lesquerella mendocina are candidate crops for arid and semi-arid cropping systems. Several reports are available on the environmental effects on growth and yield in Lesquerella, but information on the effect of temperature on plant growth and development specifically during the reproductive period in Lesquerella is limited. The objective of this work was to determine the effect of two contrasting thermal regimes after flowering on time to maturity, plant growth and biomass allocation to the different organs in L. fendleri and L. mendocina. A greenhouse experiment was conducted with plants grown at a range of 11–23 °C during the vegetative phase. After this stage, 50% of the plants of each species remained under the same temperature regime until maturity, whereas the other 50% was transferred to another module subjected to a range of 17–31 °C until maturity. The duration of the reproductive phase was reduced by 23 days in plants of both species in the 17–31 °C treatment compared to those at 11–23 °C, although no differences were observed when the length of the reproductive phase was measured in thermal-time units. Total plant biomass for both species was 20% greater in the 11–23 °C treatment. In L. fendleri, this increment occurred due to more vegetative shoot biomass, whereas in L. mendocina it was associated with greater reproductive and root biomass. No changes in biomass allocation were produced by temperature in L. fendleri, while in L. mendocina the lower temperature regime increased allocation to the reproductive organs, at the expense of a lower allocation to vegetative shoot. These results could be used to predict the specific temperature effects after flowering on yield under field conditions, and suggest that L. mendocina might be a promising perennial alternative for cooler sites.

Cold and dark or warm and light: variations on the theme of environmental control of reproduction

Seasonality is a common feature of teleost reproduction and is most marked at higher latitudes. Seasonal cycles are principally entrained by photoperiod and temperature but a range of other variables including lunar phase and social interaction may also operate. Photoperiod information is transduced through the light inhibition of pineal melatonin synthesis but the mechanism by which this regulates the reproductive endocrine system is not clear. There is less information on the specific effects of temperature but these are likely to involve effects on expression and activity of regulatory proteins. Environmental regulation of high latitude species appears to operate across a hierarchy of variables with photoperiod then temperature as primary drivers, whereas in tropical habitats, the hierarchy may be inverted.

Temperature effects in hydrodynamic properties of comb-like polymer with laterally attached mesogenic units

The specific temperature effects in hydrodynamic properties (intrinsic viscosity, sedimentation velocity and translational diffusion) of side-on comb-like polymers with molecular weights from 5.70×10 5 to 3.02×10 6 were observed in dilute solution in two different solvents, benzene and chloroform, over a temperature range from 2 to 73°C. The viscosity temperature coefficient dln[ η]/d T was found to be negative in sign in chloroform (−0.007 K −1) and positive in benzene (+0.005 K −1). Increase in temperature leads to intensification of the excluded volume effects in real benzene solution of the polymer and to weakening of those in chloroform. Simultaneously, increase in temperature leads to decreasing unperturbed dimensions of the macromolecule chain in both the solvents. This effect is more pronounced in benzene (dln〈 h 2〉/d T=−0.005 K −1, where 〈 h 2〉 is the mean-square end-to-end distance) than in chloroform (−0.001 K −1). Origins of the temperature effects are discussed with relation to the lateral structure of the macromolecule where every monomer unit contains the threecyclic mesogenic moiety which is laterally (with the middle part) attached to a side chain consisting of 11 carbon atoms.

Molecular structure of the fullerene C 70 at 825°C: : quantum-chemical molecular dynamics simulations

Molecular dynamics simulations on semi-empirical AM1 and PM3 potential energy surfaces have been performed for C 70 at the temperature of a recent electron diffraction experiment (825°C). Compared with the equilibrium structure, the average CC bond lengths are increased uniformly by ca. 0.01 Å at 825°C. Due to the lack of specific temperature effects, the simulations do not support the interpretation of the electron diffraction data in terms of exceptionally long equatorial bonds.

Facial Movement, Breathing, Temperature, and Affect: Implications of the Vascular Theory of Emotional Efference

The vascular theory of emotional efference (VTEE) states that facial action can alter the volume of air inhaled though the nose, which in turn influences brain temperature and affective states. Cooling enhances positive affect, whereas warming depresses it. Three studies assessed this hypothesised series of effects. Study 1 found that when subjects engaged facial muscles in a manner analogous to a negative emotional expression, the volume of ambient air inhaled through the nose decreased, forehead temperature (a measure of brain temperature) increased, and participants reported feeling more negative affect. Study 2 established that prevention of nasal breathing generated negative affect. Study 3 indicated that forehead temperature increased when nasal breathing was prevented, without forehead muscle movement. Further, facial movement and prevention of nasal inhalation had no effects on arm temperature, showing that facial movement has only locally specific temperature effects. The hypotheses generated from VTEE were thus generally supported, and suggest a means by which facial action can cause changes in affective state in the absence of cognitive appraisal.

The variation with temperature of positive streamer properties in air

Measurements are reported of the variation of the electric field required for propagation of positive streamers in air as a function of ambient temperature. Propagation velocities have also been measured as function of field and temperature. The results are discussed in terms of changes of air density consequent upon the temperature changes and comparisons are made with other work in which density has been changed by variation of pressure at constant temperature. There is some evidence that specific temperature effects exist. The variation of streamer velocity with air density indicates that a constant reduced total field E/N is maintained in the avalanches, replicating the streamer tip as the density is changed.

Glycolytic function in goldfish hepatocytes at different temperatures: relevance for Na+ pump activity and protein synthesis.

ABSTRACT Cellular metabolism of ectotherms may respond to temperature changes with a shift in the choice of substrate preferentially catabolized for ATP production (Johnston and Dunn, 1987). This has been shown in acclimated fish, in which a temperature-dependent switch from carbohydrates as the main fuel for energy metabolism to other fuels, or vice versa, can occur. Such shifts help to indicate the relative importance of aerobic glycolysis as an ATP-supplying process. The preferred energy source at a given temperature depends upon the temperature range investigated, as well as on the species, on the tissue and upon nutritional factors. The adaptive significance of shifts between energy sources is not always clear. While in some cases ecological arguments may provide plausible explanations (e.g. seasonal adaptation to migration and reproductive requirements; Stone and Sidell, 1981; Moerland and Sidell, 1981), evidence is accumulating that structural or functional features inherent in the metabolic organisation of the cell may also play a role in determining the nature of such responses (Sidell, 1983; Sidell and Hazel, 1987). Of particular relevance in this respect is the interaction between diffusional flux and the rate of enzymatic activity in shaping specific temperature effects on cellular metabolism.

Nonlinear spectroscopy of narrow-gap Pr—Ba—Cu—O semiconductor films with the aid of biharmonic pumping

The dependences of the efficiency η of self-diffraction of picosecond pulses on their frequency detuning Ω were determined for Pr—Ba—Cu—O semiconductor films. These dependences were similar to those already reported (for Ni and Y—Ba—Cu—O in the resistive phase) and had a central peak (η ~ 10-7 for ≤ 10 cm-1) and wide wings (η ~ 10-9 for ≥ 10 cm-1) with a jagged profile because of phonon resonances. An analysis was made of the causes of this similarity, of the asymmetry of η(Ω) relative to the sign of η, and of specific temperature effects. Although the position of a combination electron resonance (interband transition edge) of Pr—Ba—Cu—O was within the range of variation of η, its identification was complicated by the presence of nearby (on the scale of Ω) phonon modes.