Sudden Temperature Changes Research Articles

Temporal Dynamics of Scout Release-Behavior of Termitophagous Ponerine ant, Megaponera Analis

AbstractMegaponera analis is an obligate termitophagous species endemic to sub-Saharan Africa. The species forages by sending out scouts to search for termites. Once termites are located, the scouts return to the nest and recruit nest mates. Scouts face unpredictable environmental conditions, including sudden flooding, temperature changes, high winds and predation by natural enemies. We observed 519 scouting trips from 18 different colonies over three years to determine how long it takes for the colony to replace a scout that has likely died while on scouting duty or is lost due to environmental perturbations. Study areas were at Maremani, Musina, Masebe and D’nyala Nature Reserves in the Limpopo Province of South Africa. We introduced definitions of scouting turnover, scouting trip, and scouting session. Scouting turnover is the time it takes a successive scout to leave the nest for a trip, whereas a scouting trip is the journey a scout takes from the nest in search of food. Since M. analis shows bimodal foraging behavior, the morning observations were recorded as the first scouting session, while the subsequent session, which starts in the afternoon, was recorded as the second scouting session. The mean scouting turnover for all 519 trips was 9.36 ± 0.64 (SD) minutes. When turnover was divided into sessions, the first scouting session lasted a mean of 7.77 ± 12.17 (SD) minutes, while the second had 10.34 ± 18.32 (SD) minutes. The minimum turnover was zero minutes, and the maximum was 124 minutes.

Thermal gradient-induced critical current degradation in mesoscopic superconducting thin film

Abstract Superconducting materials inevitably suffer from the sudden change of temperature in localized areas in practical applications, and the concomitant thermal gradient may be detrimental to their performance. Critical current density is a key factor affecting the performance of superconductors. However, the effect of thermal gradient on the critical current density has not been identified. Here, by combining the time-dependent Ginzburg–Landau equations and the heat transfer equation, the thermal gradient and magnetic field dependence of the critical current density are systematically investigated and rationalized by exploring the behavior of vortex and magnetization. For lower magnetic fields, it is found that the thermal gradients strongly reduce the local surface barriers, which inhibits vortex entry and movement, leading to a rapid deterioration of the current-carrying capability. Under moderate magnetic fields, the critical current density corresponding to higher thermal gradients decreases more slowly with increasing magnetic field, which results from the thermal gradient-induced entry and moving of vortices along the current direction. As the magnetic field continues to increase, the variation of the critical current density transitions into a platform period and even slightly rises. The enhanced critical current is primarily attributed to the excess entry of vortices, which increases the surface barrier of the sample. With the further increase in the magnetic field, the critical current density continues to decrease due to increased magnetic field penetration. These results unveil the fundamental interplay between thermal gradients, external magnetic field, vortex, magnetization and critical current density, and provide a theoretical basis for understanding the heat-induced quenching of mesoscopic superconducting thin films in practical applications.

Simulation of metal fatigue crack analysis based on thermal environment numerical analysis in street metal sculpture design process

With the popularity of urban public art, metal materials are easily affected by environmental factors in practical applications, especially the influence of thermal environment on metal fatigue, which often leads to cracks in sculptures, affecting their service life and safety. Through the numerical analysis of thermal environment, the fatigue crack generation mechanism of street metal sculpture in the process of use is deeply discussed in order to provide theoretical support and practical guidance for sculpture design. The finite element analysis method is used to simulate the stress distribution of metal sculpture under different thermal conditions. By setting a variety of conditions such as ambient temperature and humidity, the corresponding thermodynamic model is established, and the fatigue properties of metal materials are evaluated comprehensively The numerical model is calibrated with experimental data to improve the accuracy of the simulation. It is found that the change of thermal environment significantly affects the internal stress distribution of metal sculpture, and then affects the generation of fatigue cracks. At high temperature, the fatigue limit of the material is reduced, which leads to more cracks. Under the condition of sudden temperature change, the stress concentration of the material is more obvious, and the fatigue life of the metal is significantly shortened.

Research on Hybrid Approach for Maximum Power Point Tracking of Photovoltaic Systems under Various Operating Conditions

Based on the characteristics of the whale optimization algorithm (WOA) and perturbation observation (P&O) method, this paper proposes a novel hybrid approach called the improved chaotic whale optimization combined with perturb and observe (ICWOA-P&O) method for maximum power point tracking (MPPT) control to solve the challenge of low efficiency in photovoltaic (PV) power generation under local shadows. First, the ICWOA is used for a global search to quickly locate the position of the maximum power point (MPP). Then, the P&O method is used for a fine-grained local search to quickly track the position of the global maximum power point (GMPP) with low oscillation. To ensure accuracy, the tracking performance of the ICWOA-P&O method is comprehensively compared with the WOA-P&O, WOA, and PSO models under four conditions: uniform irradiance, static local shading, dynamic shading, and sudden changes in irradiance and temperature. The simulation results verify that under the above four conditions, the ICWOA-P&O method can track the MPP continuously and stably and greatly improves the convergence time and accuracy. Compared with the other three methods, the ICWOA-P&O method can effectively obtain the fastest tracking speed (less than 0.1 s), the highest tracking accuracy (more than 99.97%), the smallest relative error (less than 0.03%), and the smallest oscillation fluctuation. Finally, this study integrated the ICWOA-P&O algorithm into the designed MPPT controller hardware and established a practical PV experimental platform based on the ICWOA-P&O control algorithm for practical tests.

Lab study on the physiological thermoregulatory abilities of older people with different frailty levels

The advent of an aging society has increased the need for a better understanding of thermal comfort requirements, especially for older people's health. Differences in thermal comfort needs among older individuals with varying frailty levels are noted, but the impact of health on physiological thermoregulation is underexplored. This study, based on the frailty classification method characterized by Fried, selected 12 non-frail (age:71.00 ± 5.41) and 12 pre-frail (age:72.68 ± 5.7) older individuals for laboratory experiments. This experiment set sudden temperature change experiments to illustrate differences in subjective perceptions and physiological changes between non-frail and pre-frail older people. Results show that non-frail individuals are more likely to complain in warmer environments. Significant differences in perception only emerged when the temperature differential between neutral and warm conditions exceeded 5 °C. Pre-frail individuals exhibited slower skin temperature changes and required more time to stabilize with the environment, particularly in the foot. Pre-frail individuals tend to sweat less in changing environments and require more time to reach stable sweating. There is positive evidence indicating that heart rate of pre-frail individuals is higher than non-frail individuals, with different changing trends observed between the two groups. When the temperature difference exceeds 5 °C, the pulse intensity trend in pre-frail individuals diverges from that of non-frail individuals. In controlling indoor environments for older people, it is essential to consider both subjective comfort and physiological thermoregulation capabilities. For older adults with frailty characteristics, applying localized warming, using small temperature differences, gradually adjusting the environment may better meet their comfort needs.

Captive spawning, early development, and larviculture of largescale blackfish, Girella punctata (Gray, 1835), and effects of macroalgae and alternative protein sources on its juvenile growth performance

The largescale blackfish, Girella punctata (Gray, 1835), inhabits rocky substrates in the coastal waters of Japan and northeastern Taiwan. Despite its commercial significance, there is limited knowledge regarding its reproductive biology due to the sparse occurrence of broodstocks in its natural environment. This study investigated the reproductive performance and embryonic development of G. punctata, assesses its feeding preferences through controlled feeding trials, and evaluates the impact of various feed types on its growth performance. In total, 124 wild-caught G. punctata were reared for 3–4 years, and their reproductive performance was assessed in 2015 and 2016. Their egg production increased with a sudden water temperature change from 17 ℃ in 2015–22 ℃ and 2016. The total and daily average egg production weights were 3589.22 and 40.79 g, respectively, whereas the total and daily average fertilized egg production weights were 1630.72 and 18.59 g, respectively; moreover, the hatching rate was 42.61 %. During embryonic development, the eggs hatched 45 h post fertilization at 19 ℃. Newly hatched larvae were 2.26 ± 0.04 mm in length with a yolk sac of 1.09 ± 0.02 mm in length. The yolk sac was almost completely absorbed 3 days post hatch (dph), when the larvae grew to a length of 3.42 ± 0.06 mm. We found that fish meal with 40 % protein was the optimal G. punctata fish diet. The weight gain in juveniles fed Cladophora fascicularis ranged from 47 % to 52 %, which was significantly higher than that in those fed Hypnea charoides (p < 0.05). The present study provided a practical guideline on the conditions required for successful fertilization and early development of G. punctata embryos and other larval stages. This information should help ensure greater survival and a higher proportion of healthy G. punctata larvae for mariculture applications.

Macroalgal Diseases: Exploring Biology, Pathogenesis, and Management Strategies

The global seaweed market is expected to reach USD 17.8 billion by 2032, fuelled by growing demand for sustainable and healthy food solutions and expanding applications in agriculture and aquaculture. However, this rapid growth poses significant challenges, particularly in managing diseases that often establish themselves in intensive macroalgal culture facilities. Red rot disease, Olpidiopsis, and green spot disease often affect marine macroalgae species of high commercial interest, as seen in Pyropia/Porphyra as has already happened for “ice-ice” malaise on Kappaphycus, causing huge economic losses. These diseases are caused by infectious agents that find their place in extreme environmental conditions, such as those characterized by sudden changes in temperature and pollution. Despite technological advances aimed at monitoring the well-being of cultivated seaweed, discrepancies between regions’ technological capabilities and species vulnerability exacerbate management difficulties. This review provides an overview of diseases prevalent among marine algae, their impact on aquaculture, and the effectiveness of currently adopted treatments. This study highlights the need to improve disease management strategies and highlights the importance of understanding host–pathogen interactions in order to mitigate future epidemics.

A new thermo-optical system with a fractional Caputo operator for a rotating spherical semiconductor medium immersed in a magnetic field

PurposeUnderstanding the mechanical and thermal behavior of materials is the goal of the branch of study known as fractional thermoelasticity, which blends fractional calculus with thermoelasticity. It accounts for the fact that heat transfer and deformation are non-local processes that depend on long-term memory. The sphere is free of external stresses and rotates around one of its radial axes at a constant rate. The coupled system equations are solved using the Laplace transform. The outcomes showed that the viscoelastic deformation and thermal stresses increased with the value of the fractional order coefficients.Design/methodology/approachThe results obtained are considered good because they indicate that the approach or model under examination shows robust performance and produces accurate or reliable results that are consistent with the corresponding literature.FindingsThis study introduces a proposed viscoelastic photoelastic heat transfer model based on the Moore-Gibson-Thompson framework, accompanied by the incorporation of a new fractional derivative operator. In deriving this model, the recently proposed Caputo proportional fractional derivative was considered. This work also sheds light on how thermoelastic materials transfer light energy and how plasmas interact with viscoelasticity. The derived model was used to consider the behavior of a solid semiconductor sphere immersed in a magnetic field and subjected to a sudden change in temperature.Originality/valueThis study introduces a proposed viscoelastic photoelastic heat transfer model based on the Moore-Gibson-Thompson framework, accompanied by the incorporation of a new fractional derivative operator. In deriving this model, the recently proposed Caputo proportional fractional derivative was considered. This work also sheds light on how thermoelastic materials transfer light energy and how plasmas interact with viscoelasticity. The derived model was used to consider the behavior of a solid semiconductor sphere immersed in a magnetic field and subjected to a sudden change in temperature.

Корневая гниль яровой пшеницы в условиях Зауралья, варианты оперативной защиты

Abstract. Root rot is a harmful and widespread disease of cereal crops. In the conditions of the Urals, Siberia, and Northern Kazakhstan, its causative agents are various species of fungi of the genus Fusarium and the fungus Bipolaris sorokiniana. The purpose of this study was to comparatively determine the effectiveness of microbiological, chemical and combined protection of spring wheat seeds. Field experiments were carried out on the experimental field of the Kurgan Scientific Research Institute of Agriculture – branch of the Ural Federal Agrarian Scientific Research Centre of the Ural Branch of the Russian Academy of Sciences (Kurgan SRIA – branch of FSBSI UrFASRC, UrB of RAS) in 2019, 2021, 2022. Scientific novelty lies in the determining the competitiveness of various methods of protecting spring wheat seeds in the conditions of the Trans-Urals within the framework of modern cultivation technology. The methods used are generally accepted in the Russian Federation. Results. In conditions of almost annual occurrence of negative natural phenomena for the growth and development of plants (droughts, frosts, sudden changes in temperature, dry winds, etc.), the use of seed treaters can be an additional stress for plants; the presence of the effect of shortening the underground internode can negatively affect field germination culture. To reduce these risks, as well as the pesticide load, we recommend using a combined method of seed protection. It involves the use of a mixture of a bacterial fungicide based on Bacillus subtilis with a chemical disinfectant at half the consumption rate. At the same time, the level of control of phytopathogens is maintained, there is no retardant effect, and economic efficiency is not inferior to the level of using a two-component chemical seed protectant (113–114 %). Chemical protection of seeds reduced the development of root rot pathogens by 63–72 %. The use of combined protection provided good control of phytopathogens, including the dominant fungi Fusarium. The predominant species from the genus Fusarium were the highly dangerous F. oxysporum, F. graminearum, F. sporotrichioides.

WEAR MECHANISM FOR DEEP-WELLS DRILLING TOOLS

When drilling deep wells with a large diameter drill bit, it is important to ensure optimum progress with the cutting tool, effectively cutting or crushing the rock through which we are penetrating for as long as possible. When drilling a well, we encounter complex conditions at depth resulting from variables such as the strength of the rock, the load on the bit, the number of revolutions of the tool, significant temperature and pressure fluctuations and the material properties of the tools used in the drilling. The article shows how mechanisms develop due to the drilling parameters used and the complex drilling conditions, which lead to wear of the cutting unit and a decrease in efficiency. The influence of the aforementioned drilling conditions on the steel materials of the roller-cone drill bit, which is the tool we use to penetrate deeper, is reflected in the change in the material properties of the steels. These changes, which are explained in the article, lead to gradual fatigue and degradation of the materials. The wear mechanism of the cutting tool is composed of the different material properties of the steel from which the roller-cone drill bit is formed, the influence of sudden temperature changes on the steel materials and erosion processes on free, newly formed surfaces, which are the result of the erosion effect.

Construction Brick Production Industry in Southern Thailand: a Case Study of Kiln

Purpose: To study the kiln that affect the construction brick production industry and to provide guidelines for solving problems. Method: This is qualitative research collecting data from 17 Kiln brick production industry Owners with in-depth interview. Data is analyzed by content and thematic analysis. Results and Conclusion: (1) Physical characteristics of the furnace square brick kiln model. The structure of this kiln is made of cooked bricks into a rectangular permanent wall. There is a firewood compartment and a brick entry door on the side. Production capacity is 50,000-100,000 bricks/stove. Specific energy was 1.6-3.8 MJ/kg of brick, some stoves use 7.8 MJ/kg brick. (2) Burning temperature. Brick firing in Thailand usually ends at 900 degrees Celsius, with brick heating, brick drying, brick kilning, and temperature reduction. which uses a fairly high temperature for burning. (3) The burning time is approximately 7 days, which corresponds to the temperature of the firing side by heating the bricks, baking the bricks, burning the bricks, and reducing the temperature. By using firewood as a leaven. Therefore, there is a lack of technology development in brick production and efficient brick firing with a long firing period. (4) Heat energy loss. Brick firing in Thailand usually ends at a temperature of 900 degrees Celsius and is then turned off for a few days. To reduce cracking due to sudden temperature changes, then turn on the kiln to let the bricks cool naturally allowing the bricks to cool naturally. The heat energy stored is left and that is a loss of heat energy. Research Implications: Brick burning uses a lot of energy, firewood as fuel, and the efficiency of the kilns used is quite low. It is likely that the efficiency of brick kilns will be improved or brick kilns with high thermal efficiency to be used as a replacement to achieve high efficiency. This allows the brick production industry to continue to exist. Originality/Value: The improvement of fuel using for Kiln in brick burning can be improved for more effectiveness and clean environment.

Temperature Estimation of Lithium-Ion Batteries Using Electrochemical Techniques

With their high energy and high power density, lithium-ion batteries (LIBs) are widely used as power sources for electric vehicles and energy storage systems, and their demand continues to grow. However, the increasing energy and power density of LIBs leads to significant heat generation issues, and reflecting these safety concerns there have been a number of recent fires of high-performance batteries. Under these circumstances, it is increasingly important to have a reliable assessment of battery safety through precise diagnostics of battery state of health (SoH). As a matter of fact, the battery management system diagnoses and evaluates battery SoH by analyzing various parameters such as voltage, current, and surface temperature of battery, and among these there is no doubt that battery temperature is a critical safety factor. As LIBs become more high-performance and large-scale, the temperature distribution inside the battery becomes more uneven, which possibly degrades performance and eventually leads to failure, so it is very important to secure the uniformity of the battery temperature and at the same time to analyze the temperature inhomogeneity and sudden temperature changes inside the battery.A typical way to estimate battery temperature is to insert a temperature sensor into the battery or attach it to the battery surface. While these methods enable direct temperature measurement, inserting a sensor can mechanically affect the internal structure of the battery, and attaching a sensor to a surface can result in delayed detection of internal cell temperature changes and may not fully reflect the battery temperature especially if there is a large temperature distribution. As an alternative, temperature estimation using electrochemical impedance spectroscopy (EIS) has received significant attention. Although EIS analysis is an indirect method of obtaining internal cell information through the electrochemical signal, it has the great advantage that it is a non-destructive method that does not affect the cell structure, and the internal cell situation is fully reflected in the electrochemical signal. Nevertheless, typical temperature estimation methods using EIS are time-consuming because they require deriving temperature-related impedance components from impedance data measured over a wide frequency range (kHz to Hz). To solve this problem, Srinivasan pioneered a method that utilizes impedance values at a single frequency for temperature estimation, which uses a specific response signal that has a clear temperature dependence but is largely unaffected by other factors (such as state of charge (SoC)). While this method can effectively reduce the cost and time spent on temperature estimation using EIS and is one of the most promising methods of estimating cell internal temperature known to date, it has been reported that the accuracy of temperature estimation is low at high temperatures for reasons that are not yet fully understood.In this study, we diagnose the problems with the existing method of estimating the internal temperature of batteries through EIS and propose a way to improve the accuracy of temperature estimation at high temperatures. For this purpose, first, we measured the impedance at various SoCs and derived the characteristic frequency representing the reaction at the solid electrolyte interphase (SEI), which is the main reaction used for temperature estimation in the previous work. In addition, we thoroughly analyzed the impedance change with temperature to more clearly understand the resistance components contributing to the impedance at the characteristic frequency. The analysis showed that impedance value at characteristic frequency, which was thought to represent only one reaction at the SEI, contained signals from other reactions (e.g. interfacial charge transfer) at higher temperatures. This situation becomes more severe as the temperature increases, and is believed to be the reason why traditional impedance-based temperature estimation methods have limited accuracy at high temperatures. We also observed that increasing the characteristic frequency to avoid this signal overlap prevented signal disturbance due to charge transfer reactions, but instead introduced another signal disturbance due to stray inductance. Based on these analyses, this study proposes a new frequency value to be used for battery temperature estimation through EIS, and at the same time presents an impedance correction method that can reliably take only the impedance signal of a specific reaction with temperature dependence without interference from other reaction signals at that frequency. It is confirmed that the temperature estimation accuracy is greatly improved when using the method presented in this study compared to the existing temperature estimation method. In this presentation, we will critically discuss why existing methods have poor temperature estimation accuracy at high temperatures, and propose an impedance-based temperature estimation method that can achieve high accuracy over a wide operating temperature range.

Investigating the impact of weather on stroke in summer.

The objective of this study is to explore how changes in weather contribute to an increase in hospital admissions for stroke in summer. We collected 96,509 cases of stroke hospitalization data in Tianjin from 2016 to 2022 summer, along with corresponding meteorological data. The generalized additive model and distributed lag nonlinear model were used to analyze the lag and cumulative effects of temperature on stroke hospitalization. The research results show both the cold effect and the heat effect in summer would increase the risk of hospitalization. The effect of daily maximum temperature on stroke hospitalization was immediate when the temperature was higher, and delayed when the temperature was lower. However, the risk of stroke hospitalization increased more significantly with increasing temperature than with decreasing temperature. In the presence of one or more of the following three weather changes: sharp temperature increase, sharp temperature decrease, continuous high temperature, the daily number of stroke inpatients were higher than the average in the same period. 83% of the Inpatient-heavy events within the study period were caused by a combination of dramatic temperature changes and continuous high temperatures. In 48% of Inpatient-heavy events, continuous high temperature weather above 30℃ for at least 4 consecutive days were observed. And 55% of high temperature weather was accompanied by high humidity. When the daily relative humidity was greater than 70% and the daily maximum temperature was between 26 and 28℃ or more than 34℃, or the daily maximum temperature changes over 10℃ within 48h, the number of daily inpatients was more than 1.2 times of the average daily inpatients. More attention should be paid to the combined effects of continuous high temperature and sudden temperature changes in summer stroke prevention.

SUBSTANTIATION OF CHANGES IN THE CERTIFICATION OF THE TRACTOR DRIVER’S WORKPLACE IN MODERN MACHINE-TRACTOR UNITS

The study aims to identify possible changes in the working conditions of tractor drivers under the computerisation of workplaces and to develop proposals for changing the requirements for sanitary standards in the design of tractors and agricultural machinery. The article analyses the impact of modern technologies on the working conditions of tractor drivers in agriculture. It investigates various aspects of work, including using on-board computers, air conditioning, and satellite navigation, and their impact on workers’ health. The authors consider health risks, such as increased noise levels and work with on-board computers, and reveal the lack of consideration of these aspects in regulatory documents. In particular, we have found that using on-board computers significantly simplifies the process of controlling agricultural machinery but can lead to increased noise and vibration levels, negatively affecting workers’ health. Some studies have shown that prolonged work with on-board computers can lead to the development of occupational diseases, such as musculoskeletal disorders, impaired vision, and others. In addition, air conditioning in tractor cabs can cause colds due to sudden temperature changes and increase the risk of legionella infection due to the water condensation accumulation in ventilation systems. The research also found that the legal and regulatory documents governing the working conditions of tractor drivers do not consider the use of modern technologies, which creates gaps in worker protection. Regulatory documents should contain requirements for the parameters of monitors and their placement in the working area of tractor drivers in agricultural production, such as adjusting the reflectivity of the screen, the main adjusted visual characteristics of monitors, and the location of video terminals in the tractor cab without being directly in the line of sight. It is necessary to develop measures to prevent the overwork of tractor drivers. Regulations should include rules for the use of air conditioners, as well as for cleaning air conditioning ducts and replacing filters on time. The general conclusion is that there is a need to strengthen the regulation of tractor drivers’ working conditions and to include requirements for using modern technologies in the relevant regulations. These measures will ensure the safety and health of workers in agriculture and reduce the risk of occupational diseases. Keywords: machine-tractor unit, tractor driver, workplace certification, labour protection, video terminal.

A PWR core power control using optimized PID controller with SQP based on control rod positioning and variable coolant flow rate

To ensure safety and stability, it is optimal for nuclear power plants to operate at their nominal power level. However, to meet the needs of power systems, NPPs must also be able to adjust their output for load-following purposes. This necessitates finding an effective control algorithmto maintain stable/safe operating conditions. The current study investigates the performance of PID controllersoptimized using Sequential Quadratic Programming algorithm and applied using two control techniques: control rod positioning and variable coolant flow rate. Simulation is done using model of four-loop Westinghouse PWR-1200 MW nuclear reactor. The proposed controller’s performance is evaluated in three scenarios:sudden control rod withdrawal, sudden change in coolant inlet temperature, and linear load tracking. The influences of model parametric uncertainty are also investigated. Simulation results revealed that the performance of the control algorithm applied using variable coolant flow rate was superior to the one usingcontrol rod positioning.

Climate–Growth Relationships of Mongolian Pine (Pinussylvestris var. mongholica) along an Altitudinal Gradient of Northeast China

To study the radial growth of Mongolian pine (Pinus sylvestris var. mongholica, MP) trees in response to climatic factors against the global warming background in the northeast part of the Greater Khingan Mountains (GKM), 101 tree cores were collected at contrasting altitudes (1100 and 650 m) in the Mordoga area, a tree-ring width chronology of MP was established for that region at both altitudes, and the relation between climatic factors and ring width trends at different time scales was investigated. The results revealed four major findings. (1) The ring width chronology of MP in the low-altitude area has better quality. (2) The growth of MP at high (low) altitude was mainly influenced by temperature (precipitation) factors. (3) Before a sudden change in temperature, there was a decreasing trend in the annual indices of MPs at higher altitudes. The chronological coefficients of MPs at both altitudes showed a significant upward trend after the increase in temperature. (4) The sliding analysis results showed that the stability of the relationship between MP growth and its response to climatic factors at both altitudes was also mostly similar. MP growth is relatively stable and sensitive and to climatic factors as temperatures increase.

Long-term thermal stress induces hepatic injury and alters the thermotolerance response in Hong Kong catfish (Clarias fuscus)

Global climate change has a significant impact on fish survival and the aquaculture industry. Even highly adaptable organisms like Siluriformes fish are susceptible to these effects. This study investigates the consequences of extreme high temperature on Hong Kong catfish (Clarias fuscus), a species known for its long-term habitation in tropical and subtropical regions. In this study, C. fuscus were cultivated for 90 days at high temperature (HT, 34 °C) and normal temperature (NT, 26 °C), followed by subjecting the two groups to high temperature stress (34 °C) and temperature recovery (26 °C). The hepatic histology, biochemical, and transcriptomic characteristics of the species were examined before acute high temperature stress (NT-C, HT-C), after acute high temperature stress (NT-T, HT-T), and after temperature recovery (NT-R, HT-R). The histological analysis revealed that long-term heat stress damaged the liver tissue of C. fuscus. Furthermore, significant damage was observed in the liver tissues of the NT group under acute high temperature stress, while no further damage was observed in the HT group. The biochemical analysis showed that 90 days of heat stress altered the body's immune and oxidative balance, resulting in an increase in alkaline phosphatase (ALP), alanine aminotransferase (ALT), catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities, and a decrease in malondialdehyde (MDA) content. Upon acute heat stress, the liver function of the NT group was disordered and unable to produce enough total-bilirubin (T-BIL), while the aspartate aminotransferase (AST) activity of the HT group was more susceptible to being affected. Long-term heat stress led to significant changes in gene expression, with the NT group showing three times more differentially expressed genes (DEGs) identified in the liver compared to the HT group under acute heat stress conditions. Analysis of DEG enrichment during the same treatment period in both groups revealed significant differences in amino acid metabolism and lipid metabolism pathways. These results suggest that long-term heat stress caused liver tissue damage in C. fuscus, altering immune and oxidative balance, enzyme activity sensitivity, as well as the body's response to acute heat stress pathways and intensity. This study lays the groundwork for future investigations into fish adaptability to sudden temperature changes and aquaculture strategies to mitigate heat stress in fish facing extreme temperatures.

Transient global amnesia

Transient global amnesia

Thermotolerance of environmental fungi captured from indoor air.

While more than six million species make up the fungal kingdom, less than 300 cause disease in humans, in part because many fungal species are unable to grow at temperatures at or above human body temperature. However, there is concern that as global temperatures increase, fungal species that do not currently pose a risk to human health may adapt to growth at higher temperatures, opening the door for the emergence of new human fungal pathogens. This study assessed the growth of five fungal isolates captured from indoor air at temperatures up to 38°C. All five isolates grew well at 24-27°C, grew poorly or not at all at 36°C, and none grew at 38°C. We then investigated the growth of three fungal isolates captured from indoor air at 36 - 39°C when the growth temperature was gradually increased from ambient room temperature to 36 - 39°C, compared to growth after a sudden change of temperature from room temperature to 36 - 39°C. All three isolates still exhibit poor to no growth at 39°C. This research was supported by a NASA-WVSGC Undergraduate Research Fellowship (AEC) and a NASA-WVSGC Research Enhancement Award (LSR).

Effect of Static Magnetic Field on the Quality of Pork during Super-Chilling Storage.

Fresh pork tenderloin was stored at -3 °C under different static magnetic fields (SMF) of 0, 4, and 10 mT (control, MF-4, and MF-10) to investigate their physicochemical properties changes during storage of 8 days. The initial equilibrium temperature of the samples stored with 4 mT MF was found to be -2.3 °C, which was slightly lower (0.3 °C) than that the control value. The super-chilling phenomenon on the pork was then observed, as the samples stored under the magnetic field did not freeze throughout storage period, but the control experienced a sudden change in temperature after 138 h and then froze. The preservation effect of MF-4 on meat quality was the best in all treatment groups. MF-4 achieved a higher water-retention rate, with drip and cook losses of 6.5% and 29.0% lower than the control, respectively. Meanwhile, the MF-4 effectively delayed the color change in the meat during the storage and the texture hardening after cooking, and effectively controlled the growth of the total volatile saline nitrogen content on the samples. In addition, MF-4 delayed the reduction in myofibrillar protein solubility, sulfhydryl content, and emulsification capacity, indicating that this field inhibited the denaturation of myofibrillar protein. This study can be considered as an application reference of magnetic fields during meat storage at a super-chilled temperature.