Effects Of Temperature Stress Research Articles

Mechanical Behavior of Secondary Lining in Super Large-Span Tunnels Considering Temperature Effects

Temperature stress has a significant impact on the structural stress of (super) large-span tunnel lining, which can easily lead to structural fatigue damage and premature cracking. With the increasing scale and quantity of super large-span tunnels, the issue of temperature stress in secondary lining has attracted widespread attention. Previous studies have paid little attention to the influence of temperature stress on the structural internal forces of ordinary small–medium-span tunnels, but this influence cannot be ignored for super large-span tunnels. We take the Letuan Tunnel (a double-hole eight-lane tunnel) of the Binzhou-Laiwu expressway renovation and expansion project in Shandong Province as a case study and analyze the mechanical response of the secondary lining through on-site measurement. Moreover, a numerical simulation was conducted to evaluate the effects of self-weight and temperature stress on the secondary lining of the case tunnel. The results indicate that: the stress of the secondary lining concrete and steel bars is greatly affected by seasonal temperature changes. The compressive stress of the concrete and steel bars is significantly greater in summer than in winter, and the tensile stress is greater in winter than in summer. Furthermore, multiple measurement points have shown a phenomenon of transition between tensile and compressive stress states. The stress of concrete and steel bars fluctuates periodically with a sine function over time, with a fluctuation period of one year. The structural stress increases with the increase of summer temperature and decreases with the decrease of winter temperature. The fluctuation amplitude of stress in the inner side of the lining concrete and steel bars is greater than that on the outer side. Among them, the stress amplitudes of the inner and outer sides of the concrete are between 0.77–1.75 MPa and 0.44–1.07 MPa, respectively, and the stress amplitudes of the inner and outer steel bars are between 5–31 MPa and 7–13 MPa, respectively. The safety factors in summer are lower than those in winter. The minimum safety factors for secondary lining in summer and winter are 3.4 and 4.6, respectively, which can meet the safety requirements for service. The average axial forces of the secondary lining under the coupling effects of self-weight and temperature in winter and summer are 528 MPa and 563 MPa, respectively, which are significantly greater than the combined axial forces under their individual effects. The bending moment distribution of the secondary lining at the tunnel vault, inverted arch, wall spring and other positions under the coupling effect of self-weight and temperature is different from or even opposite to the bending moment superposition result under the two individual actions. The achieved results reveal that the influence of temperature stress on the service performance of the lining structure cannot be ignored, and the research results can provide useful reference for similar tunnels and related studies.

Integrated transcriptomic and proteomic analyses reveal the molecular mechanism underlying the thermotolerant response of Spodoptera frugiperda

Spodoptera frugiperda (Lepidoptera: Noctuidae) is a highly destructive invasive pest with remarkable adaptability to extreme climatic conditions, posing a substantial global threat. Although the effects of temperature stress on the biological and ecological properties of S. frugiperda have been elucidated, the molecular mechanisms underlying its responses remain unclear. Herein, we combined transcriptomic and proteomic analyses to explore the key genes and proteins involved in thermotolerance regulation in S. frugiperda larvae at 42 °C. Overall, 1528 differentially expressed genes (DEGs) and 154 differentially expressed proteins (DEPs) were identified in S. frugiperda larvae under heat stress, including antioxidant enzymes, heat shock proteins (Hsps), cytochrome P450s, starch and sucrose metabolism genes, and insulin signaling pathway genes, indicating their involvement in heat tolerance regulation. Correlation analysis of DEGs and DEPs revealed that seven and eight had the same and opposite expression profiles, respectively. After nanocarrier-mediated RNA interference knockdown of SfHsp29, SfHsp20.4, SfCAT, and SfGST, the body weight and mortality of S. frugiperda larvae significantly decreased and increased under heat stress, respectively. This indicates that SfHsp29, SfHsp20.4, SfCAT, and SfGST play a crucial role in the thermotolerance of S. frugiperda larvae. These results provide insight into the mechanism of heat tolerance in S. frugiperda.

Temperature stress (cold and heat) strongly affect the phytotoxicity of polycyclic aromatic hydrocarbon (phenanthrene) to wheat

AbstractAnthropogenic activity could create different threats leading to irreversible changes in the global environment and, as a consequence, posing varied stressful conditions acting together (combined stress) on organisms. Our research concerned the combined stress of two of the main threats to soil health and plant health: temperature stress and pollution. The aim of this research was the quantitative assessment of the impact of temperature stress on the phytotoxicity of PAHs (polycyclic aromatic hydrocarbons; specifically, phenanthrene, which is a widespread, harmful organic contamination of soil) on the growth of wheat seedlings in relation to the level of soil contamination by phenanthrene (0–1000 mg kg−1 dry mass of soil) and the type of temperature stress: cold (10°C) and heat (35°C) stress, in three different soils. Earlier studies have investigated the effect of temperature stress on PAH toxicity mainly on soil invertebrates. However, the impact of temperature stress on PAH phytotoxicity towards crop plants, which are important for human food security but could be affected by chemical soil degradation, is still poorly understood. Our results indicated that the phenanthrene phytotoxicity was significantly enhanced by cold stress and heat stress. The effects of cold and heat temperature stress increased with increasing phenanthrene level. Our research is important for improving the risk assessment of PAH and food security forecasting.

Elevated CO2 ameliorates the high temperature stress effects on physio-biochemical, growth, yield traits of maize hybrids

The rising temperatures and levels of carbon dioxide in the atmosphere are anticipated to have a significant impact on the productivity of agricultural crops. Although, the individual effects of elevated CO2 and temperature have been extensively studied in C3 and C4 crops, there remains a scarcity of research investigating their interactive effects specifically on maize hybrids. The impact of elevated temperature and its interaction with elevated CO2 on phenology, physiology, biomass, and grain yield of maize hybrids was assessed in a field experiment using Free Air Temperature Elevation (FATE) facility. The results showed that elevated temperature (eT) increased the anthesis silking interval (ASI), while the presence of elevated CO2 along with elevated temperature (eT + eCO2) mitigated this effect. The differential expression were observed between hybrids depending on their genetic potential. Furthermore, the net photosynthetic rate (Anet), stomatal conductance (gs), and transpiration rate (Tr) of hybrids decreased under elevated temperature but eT + eCO2 condition helped in reverting its impact to some extent. In term of leaf composition, the highest level of total soluble sugars (TSS) and starch was observed under eT + eCO2 conditions, possibly due to improved Anet in the presence of elevated eCO2. The negative impact of eT was also evident through increased proline and MDA content, but eT + eCO2 ameliorated the adverse effect of eT. The biomass and grain yield also responded similarly, among the hybrids 900M GOLD recorded superior performance for grain yield at eT condition exceeding 35 °C. On the other hand, DHM117 experienced a significant reduction in grain yield under eT, but performed better under eT + eCO2 due to its improved physiological response to eCO2. The study indicated that elevated levels of carbon dioxide can actually mitigate the detrimental effects of elevated temperature on maize crop. This positive impact on maize crop can be attributed to an enhanced physiological performance in the presence of eCO2 which enables the plants to maintain satisfactory yield levels despite the challenging environmental conditions.

Effect of Temperature and Water Stress on the Antioxidant and Antidiabetic Activities of Thymus vulgaris Essential Oil

Effect of Temperature and Water Stress on the Antioxidant and Antidiabetic Activities of Thymus vulgaris Essential Oil

Effect of temperature and shear stress on properties of nanovesicles carrying hydrolyzed pollen protein

In this study, the effect of storage (65 °C, 24 h) and shear rates (2-100 s−1, 10 min) on the particle size, poly-dispersity index (PDI), encapsulation efficiency (EE), Angiotensin-converting enzyme (ACE) and DPPH radical inhibition, iron ion reduction ability and flow behavior of nanovesicles containing hydrolyzed bee pollen (produced by alcalase and pepsin) were evaluated. Nanoliposomes were coated by chitosan (0.2 % w/w). After storage at 65 °C, the size of the nanovesicles raised 2–2.5 folds while EE showed 5–8 % decline. ACE and DPPH radical inhibition activity were also decreased. After applying the shear stress, PDI was increased significantly (P<0.05), while EE of the nanoniosomes showed a drastic decline (P<0.05). Nanoliposomes and nanoniosomes exhibited decline in the ACE inhibitory and antioxidant activity. At low shear rates Newtonian-like and weak pseudo-plastic behavior of the chitosan-coated nanoliposomes were observed. The flow index (n), (k) and (R2) indicated the suitability of power law model for describing the flow characteristics.

Effects of cadmium exposure on haemocyte immune function of clam Ruditapes philippinarum at different temperatures

Haemocytes are crucial for the immune defence of mollusks. It is important to explore the immune performance of haemocytes of mollusks under the stress of heavy metals with global warming. In order to study the effects of cadmium (Cd) exposure and temperature stress on the haemocyte immune function of clam Ruditapes philippinarum, clams were exposed to different Cd concentrations (0.05, 0.10 and 0.25 mg/L) at 20 °C, 25 °C and 30 °C respectively. Haemocyte mortality, reactive oxygen species (ROS) and superoxide dismutase (SOD) activity were measured at day 1, day 3, day 5 and day 7. The results showed that the changes of the three indexes were not obvious when exposed to 0.05 mg/L of Cd at 20 °C, while significant differences were observed with the increase of temperature, Cd concentration and exposure time. Under a condition of relative high temperature coupling with high concentration of Cd, the clams were significantly influenced, showing an obvious synergistic effect. Selected indexes reflect the clam's response to the combined stress of temperature and Cd. Moreover, R. philippinarum might be an ideal biological index species to the Cd pollution.

Proteome trait regulation of marine Synechococcus elemental stoichiometry under global change.

Recent studies have demonstrated regional differences in marine ecosystem C:N:P with implications for carbon and nutrient cycles. Due to strong co-variance, temperature and nutrient stress explain variability in C:N:P equally well. A reductionistic approach can link changes in individual environmental drivers with changes in biochemical traits and cell C:N:P. Thus, we quantified effects of temperature and nutrient stress on Synechococcus chemistry using laboratory chemostats, chemical analyses, and data-independent acquisition mass spectrometry proteomics. Nutrient supply accounted for most C:N:Pcell variability and induced tradeoffs between nutrient acquisition and ribosomal proteins. High temperature prompted heat-shock, whereas thermal effects via the "translation-compensation hypothesis" were only seen under P-stress. A Nonparametric Bayesian Local Clustering algorithm suggested that changes in lipopolysaccharides, peptidoglycans, and C-rich compatible solutes may also contribute to C:N:P regulation. Physiological responses match field-based trends in ecosystem stoichiometry and suggest a hierarchical environmental regulation of current and future ocean C:N:P.

Bias and Temperature Stress Effects in IGZO TFTs and the Application of Step-Stress Testing to Increase Reliability Test Throughput

Bias and Temperature Stress Effects in IGZO TFTs and the Application of Step-Stress Testing to Increase Reliability Test Throughput

Effects of low temperature stress on the physiology and growth of &lt;i&gt;Caragana korshinskii&lt;/i&gt; seedlings from different mother tree ages

Effects of low temperature stress on the physiology and growth of &lt;i&gt;Caragana korshinskii&lt;/i&gt; seedlings from different mother tree ages

Effect of Low Temperature Stress and Acclimation on Growth and Photosynthetic Parameters in Bitter Gourd Seedlings

Effect of Low Temperature Stress and Acclimation on Growth and Photosynthetic Parameters in Bitter Gourd Seedlings

May DNA analyses be biased by hidden oxidative damage? Voltammetric study of temperature and oxidation stress effect.

The analysis of nucleic acids is one of the fundamental parts of modern molecular biology and molecular diagnostics. The information collected predominantly depends on the condition of the genetic material. All potential damage induced by oxidative stress may affect the final results of the analysis of genetic material obtained using commonly used techniques such as polymerase chain reaction or sequencing. The aim of this work was to evaluate the effects of high temperature and pH on DNA structure in the context of the occurrence of oxidative damage, using square-wave voltammetry and two independent research protocols. We resulted in visible oxidation damage registered in acidic conditions after the thermal denaturation process (pH 4.7) with changes in the intensity of guanine and adenine signals. However, using phosphate buffer (pH 7.0) for DNA denaturation negatively affected the DNA structure, but without any oxidized derivatives present. This leads to the conclusion that oxidation occurring in the DNA melting process results in the formation of various derivatives of nucleobases, both electrochemically active and inactive. These derivatives may distort the results of molecular tests due to the possibility of forming complementary bonds with various nucleobases. For example, 8-oxoguanine can form pairs with both cytosine and adenine.

Quality monitoring and control for plasticization of acrylonitrile‐butadiene‐styrene regrind polymer in injection molding

AbstractTo meet net‐zero carbon emissions in injection molding, it is desirable to use regrind polymers in plastic parts fabrication. However, the quality of regrind polymer differs from virgin polymer due to the effects of temperature, pressure, and shear stress in the prior molding process. Consequently, the molded components differ in quality compared to those made from virgin material. This study investigates the feasibility of enhancing the quality consistency of regrind plastic components by controlling melt quality in plasticization. The evaluation of melt quality involves extracting two quality metrics from the pressure signal (i.e., the peak pressure and the pressure integral). They are then used to adjust the plasticization parameters as required to ensure that the weight and dimensions of the final regrind parts approach those of parts produced using virgin polymer. The experimental results show that the pressure integral effectively indicates the quality variation of the molded part during the injection molding of regrind polymer. Notably, by adjusting the back pressure, the quality of the molded part closely resembles that of the part made from virgin feedstock after six shots.

Physiological and Biochemical Effect of Elevated Night Temperature Stress on Bread Wheat (Triticum aestivum L.)

A laboratory experimentation was done in the Department of Plant Physiology, Institute of Agricultural Sciences, Banaras Hindu University to evaluate elevated night temperature effect in wheat (Triticum aestivum L.) to see the response in some antioxidant and biochemical parameters in two wheat cultivars viz. HUW-234 (comparatively tolerant to heat stress) and sonalika (comparatively susceptible to heat stress). A significance difference was recorded in the parameters pertaining to antioxidant system includes catalase, SOD and APX activity were found to increase substantially when the plants kept under stress conditions (250C/ 240C day and night temperature) than the plants kept under controlled condition (250C/150C day and night temperature). The percent increase in the antioxidant enzyme activity was found to be more in the tolerant genotype (HUW-234) than in the susceptible genotype (Sonalika). There was 23.52 % increase was reported in the catalase activity by tolerant genotype when kept under stress conditions than those kept under control. Significant reductions were reported in most of the photosynthetic and membrane parameters viz., chlorophyll ‘a’, chlorophyll ‘b’ and membrane thermostability index. Similar percent reduction was reported with respect to biochemical parameters (total protein content, starch content and soluble sugar content) in the susceptible variety kept under high night temperature regime. Based on the pooled data of two-year experimentation it can be concluded that variety HUW-234 was found to be more tolerant than variety sonalika to HNT stress.&#x0D; Key Words: High night temperature, Wheat, Catalase activity, Anti-oxidant system.

Influence of environmental factors on seed germination and seedling emergence of Amaranthus blitoides S. Watson and A. hybridus L.

AbstractAmaranthus blitoides S. Watson and A. hybridus L. are common herbaceous annual summer weeds in different regions of Iran, which produce a large number of small seeds per plant. The goal of these experiments was to determine seed germination cardinal temperature and investigate the effect of constant temperature, osmotic and salt stresses, stratification, flooding duration, after‐ripening and seed planting depth on seed germination and seedling emergence. Two‐piece segmented, dent‐like and beta four‐parameter models were used to investigate the relationship between germination rate and constant temperature. The dent‐like model showed the best description of the effect of constant temperature on seed germination rate of both A. blitoides and A. hybridus. Optimal seed germination of A. blitoides occurred at 35°C, but in A. hybridus optimum germination was observed in a range of constant temperatures from 30 to 40°C. Osmotic and salt stresses and flooding adversely affected seed germination of both species. After ripening for 6 months increased germination percentage of both A. blitoides and A. hybridus. Maximum seedling emergence of A. blitoides (42.8%) and A. hybridus (44.9%) occurred at a planting depth of 3.3 cm, whereas further increased planting depth minimized seedling emergence of both weeds. Information obtained from this study will help us to develop effective techniques for management of A. blitoides and A. hybridus.

Effect of temperature, pretreatments, gibberellin (GA3), salt and drought stress on germination of Thymus satureioides coss of Morocco

Thymus satureioides Cosson is an endemic medicinal and aromatic plant species of both Morocco and Algeria, holds significant cultural and economic importance. It is used in traditional medicine to treat various diseases and also as a culinary spice herb. T. satureioides has become a key export for Morocco. However, increasing market demand and the effects of climate change have led to a decline in its wild populations, raising concerns about the scarcity of this valuable natural resource. To address these challenges, a comprehensive understanding of the environmental requirements for the germination of T. satureioides is essential for planning and prioritizing conservation efforts in its native habitats. In this context, the aim of this study was to assess the combined effects of various pretreatments and temperature and of salinity, drought stress, and gibberellin on the germination parameters of T. satureioides. Seeds were collected from a wild plant population in the Anti-Atlas Mountains. The tests included five pretreatments (mechanical scarification, sulfuric acid (95%), dry heat, boiling water and hydrogen peroxide) in conjunction with five temperature conditions (10, 15, 20, 25 and 30 °C). Additionally, six concentrations of sodium chloride (0, 25, 50, 100, 150 and a 200 mM), six water potential levels of polyethylene glycol (PEG-6000) (0, −0.07, −0.14, −0.22, −0.32 and - 0.53 MPa) and six concentrations of gibberellin (0, 50, 100, 500, 1000 and 2000 ppm) were tested. Results showed that seeds can germinate without any treatment. However, seeds treated with dry heat followed by incubation at 20 °C improved all the germination parameters. In addition, germination parameters progressively decreased and delayed with increasing levels of both salt and water stress. Without stress, the germination percentage was 100%, with increasing salt stress to 200 mM germination was completely inhibited. Although, seeds showed a low germination percentage (5,67%) at the highest osmotic potential (−0.53 MPa).

A thermo-mechanical simulation for the stability analysis of a horizontal wellbore in underground coal gasification

The stability analysis of horizontal wells is essential for a successful underground coal gasification (UCG) operation. In this paper, a new 3D coupled thermo-mechanical numerical modeling is proposed for analyzing the stability of UCG horizontal wells. In this model, the effect of front abutment stresses, syngas pressure, syngas temperature and thermal stresses is considered to predict the mud weight window and drilling mud pressure during UCG process. The results show that the roof caving in UCG panel has a greatest impact on the stability of horizontal well. Moreover, when the time of coal gasification is increased, the well convergence increases and for more stability it is necessary to increase the drilling mud pressure. This research was carried out on the M2 coal seam in Mazino coal deposit (Iran). The results showed that the mud weight window for horizontal well drilling is between 0 and 33 MPa. The appropriate stress for the maximum stability of the horizontal well, taking all the thermal and mechanical parameters into account, is 28 MPa. The suggested numerical method is a comprehensive and consistent way for analyzing the stability of horizontal wells in UCG sites.

Cultivation manipulating zeaxanthin-carotenoid production in Arthrospira (Spirulina) platensis under light and temperature stress

Arthrospira (Spirulina) platensis is highly nutritious and most promising cyanobacterium for healthy compounds. In this study, the effect of light and temperature stress on zeaxanthin production in A. platensis C1 (PCC9438) were investigated. Under an optimal condition (35 °C, PPFD of 100 μmol photons m−2 s−1), the algal growth revealed a specific growth rate (μ) of 0.024 h−1, with the carotenoid yield and content of 3.64 mg L−1 and 4.66 mg g−1, respectively, when cells were grown for 96 h. Whereas that of the isothermally grown under sub-optimal temperatures (16 °C, 20 °C, 37 °C, 39 °C and 43 °C), the growth rates and carotenoid yields were very low, ranging from 0.001 to 0.021 h−1 of the specific growth rate, and varied from 0.17 to 3.05 mg L−1 and 0.64 to 4.51 mg g−1 of carotenoid yield and content, respectively. Nevertheless, employing a temperature shift strategy by transferring the algal culture to high temperature (42 °C) led to the increment of total carotenoids by about 12 % and zeaxanthin content and yield by 35.6 % and 22.1 %, respectively, compared to the control, which had a yield and content of 0.68 mg L−1 and 0.87 mg g−1, respectively, within 48 h. Furthermore, altering light intensities during the cultivation period, algal biomass significantly increased by 59 % under high light stress (1000 μmol photons m−2 s−1) compared to the control (0.78 g L−1). Additionally, zeaxanthin yield and content increased by 104.4 % and 28.7 %, respectively, under 1000 μmol photons m−2 s−1. We therefore proposed that light/temperature stress shifting strategy for the cultivation of A. platensis C1 could be used to enhance its nutraceutical value.

Foliar Application of Melatonin Positively Affects the Physio-Biochemical Characteristics of Cotton (Gossypium hirsutum L.) under the Combined Effects of Low Temperature and Salinity Stress.

Low temperature and soil salinization during cotton sowing and seedling adversely affect cotton productivity. Exogenous melatonin (MT) can alleviate the damage caused to plants under non-biological stress; thus, applying MT is a means to improve the growth condition of crops under stress. However, achieving this goal requires a thorough understanding of the physiological regulatory mechanisms of MT on cotton seedlings under low temperature and salinity stress. This study could bring new knowledge on physio-biochemical mechanisms that improve the tolerance of cotton seedlings to combined effects of low temperature and salt stress using an exogenous foliar application of MT. The phytotron experiment comprised two temperature levels of cold stress and control and five MT treatments of 0, 50, 100, 150, and 200 μM and two salinity levels of 0 and 150 mM NaCl. Compared with the control treatments (non-salinity stress under cold stress and control), the combined stress of salt and low temperature reduced cotton seedlings' biomass and net photosynthetic rate (Pn), aggravated the membrane damage, reduced the potassium (K+) content, and increased the sodium (Na+) accumulation in the leaves and roots. Under NaCl stress, exogenously sprayed 50-150 μM MT increased the biomass and gas exchange parameters of cotton seedlings under salt and low temperature combined with salt stress, reduced the degree of membrane damage, and regulated the antioxidant enzyme, ion homeostasis, transport, and absorption of cotton seedlings. The pairwise correlation analysis of each parameter using MT shows that the parameters with higher correlation with MT at cold stress are mainly malondialdehyde (MDA), peroxidase (POD), and catalase (CAT). The highest correlation coefficient at 25 °C is observed between the K+ and Na+ content in cotton seedlings. The conclusion indicates that under salt and low-temperature stress conditions, exogenous application of MT primarily regulates the levels of Pn, superoxide dismutase (SOD), andPOD in cotton seedlings, reduces Na+ and MDA content, alleviates damage to cotton seedlings. Moreover, the most significant effect was observed when an exogenous application of 50-150 μM of MT was administered under these conditions. The current study's findings could serve as a scientific foundation for salinity and low-temperature stress alleviation during the seedling stage of cotton growth.

INFLUENCE OF THERMAL STRESS ON THE FORMATION OF CRACKS IN THE SILICATE COATING OF THE HEAT EXCHANGE TUBE

The effect of temperature stress on the silicate coating of heating tubes has been considered. Deformation caused by temperature changes in silicate coating in heating tubes causes micro-macro cracks to appear on the surface of the coating. Taking these into account, the characteristics of temperature stress changes were studied. With this, a mathematical expression was obtained by the mathematical modeling of temperature stress. The theoretical and graphical dependencies of the distribution of temperature energy inside the tube? The coating in the external and internal systems is presented separately, and a wide explanation and analysis is given at the same time of expression with its analysis, it was interpreted on the basis of the works processed in the Matlab program. Currently, the results obtained as a result of the application of silica-coated pipes in various areas of SOCAR are being continued. The application of silica-coated pipes in various areas of SOCAR continues to give positive results. Based on the main data and results of the conducted research, a report on the efficiency of the operating condition was made, efficiency is increased by 2.0-2.5 times, and reliability and longevity are fully ensured. Keywords: silicate coatings, thermal conductivity, corrosion, temperature, resistance, durability.