Theoretical temperature calculation in the cutting area in drilling cortical bones

To date, analysis of temperature in the drill area of cortical bone have been limited to measurements with thermocouple systems at a certain distance from the drill hole. Many authors equate this temperature measurement with the drill--cortical bone interface temperature. In order show that there is a temperature difference, a drill hole was simulated with the aid of the "Finite Element Method". The interface temperature was calculated by the energy distribution. It was shown, that for "dry" and "watercooled" drilling, the drill hole temperature was 13 degrees C higher than the temperature measured with the thermocouple systems at a distance 0.5 mm of from the drill hole. In particular when using "watercooled" drills for bone and dental surgery, the temperature may be higher than the bone damage limit of 44 degrees C for lengthy and 50 degrees C for brief drilling.     

Hourly variations in rectal temperature and prolactinemia in the creole goat kept outside in a tropical environment

Rectal temperature and plasma prolactin level were measured hourly in "creole goats" during 27 consecutive hours in March, July and November. Simultaneously, air, "black-globe" temperature and relative humidity were measured at the height of the animals. Rectal temperature and plasma prolactin level varied according to hour and season and were always higher during the day than during the night. Plasma prolactin level increased dramatically for 3 h after dusk only in March. Rectal temperature showed a significantly higher correlation with air temperature than with "black-globe" temperature. On the contrary, plasma prolactin level was more significantly correlated with "black-globe" temperature than with air temperature. When all seasons and hours were pooled, "black-globe" temperature showed a threshold (32-34 degrees C), beyond which prolactin reached values higher than 100 ng/ml. Rectal temperature was always significantly correlated with plasma prolactin level. Plasma prolactin level as an index of thermal stress and the role of prolactin in thermoregulation have been discussed.     

Variations in digital temperature during frontal EMG biofeedback training in normal subjects

During frontal EMG biofeedback training, the relationship between frontal EMG and digital skin temperature was investigated in two experiments, which varied the number of baseline and feedback sessions. The results of Experiment 1 suggested a general relaxation effect, where digital temperature increased as frontal EMG decreased, especially for subjects with initially low hand temperature. Experiment 2 extended the number of baseline and feedback sessions and qualified the results of Experiment 1. EMG and digital temperature did not simultaneously converge toward general relaxation over the extended baseline or feedback sessions in Experiment 2. Furthermore, when the feedback signal was introduced, digital temperature dropped quickly but recovered to baseline levels within three feedback sessions; this drop in digital temperature was interpreted within the context of attentional demands of the biofeedback task. The results appeared consistent with the view that frontal biofeedback training teaches a discriminative skill of lower frontal EMG, and that this skill does not readily generalize to digital skin temperature.This research was supported by Grant 2 S06RR08038-17 funded by the National Institutes of Mental Health.     

Temperature of the cerebral cortex and its connection with the egg in white rats in free behavior

In chronic experiments on rats in free behavior thermistors have been used to record the temperature of the cerebral sensomotor cortex together with recording of the EEG of the neocortex and hippocampus. The sensitivity of recording of temperature was 10^–2 deg/cm. Detailed comparison of the temperature variations with changes in the EEG in "slow" and "rapid" sleep and also alertness revealed a correlation between the appearance of the hippocampal -rhythm (short bursts and long periods in the alert state and in "rapid" sleep), on the one hand, and temperature rises of greater or lesser intensity (maximum on passing from "rapid" sleep), on the other. On desynchronization of the EEG without hippocampal -synchronization no rise in temperature in the brain was observed. In "slow" sleep various forms of correlation between the EEG and the temperature of the cortex were noted: slow, smooth temperature drop developing with growth of synchronization; appearance against the background of this drop of short temperature rises the ascending phase of which corresponded to the period of rise in synchronization and a temperature drop phase corresponding to the period of desynchronization in the microcycles of slow sleep; disappearance of such temperature fluctuations after desynchronization before the onset of "rapid" sleep. Thus, the link between the fluctuations in brain temperature and its electrogenesis is of a complex character with clear correspondence between the rise in temperature and the on-set of the hippocampal -rhythm.N. I Grashchenkov Laboratory of Problems of Control of Functions in the Human and Animal Body, Academy of Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 2, No. 6, pp. 618–626, November–December, 1970.     

Minireactor-based high-throughput temperature profiling for the optimization of microbial and enzymatic processes

Background

Bioprocesses depend on a number of different operating parameters and temperature is one of the most important ones. Unfortunately, systems for rapid determination of temperature dependent reaction kinetics are rare. Obviously, there is a need for a high-throughput screening procedure of temperature dependent process behavior. Even though, well equipped micro-bioreactors are a promising approach sufficient temperature control is quite challenging and rather complex.

Results

In this work a unique system is presented combining an optical on-line monitoring device with a customized temperature control unit for 96 well microtiter plates. By exposing microtiter plates to specific temperature profiles, high-throughput temperature optimization for microbial and enzymatic systems in a micro-scale of 200 μL is realized. For single well resolved temperature measurement fluorescence thermometry was used, combining the fluorescent dyes Rhodamin B and Rhodamin 110. The real time monitoring of the microbial and enzymatic reactions provides extensive data output. To evaluate this novel system the temperature optima for Escherichia coli and Kluyveromyces lactis regarding growth and recombinant protein production were determined. Furthermore, the commercial cellulase mixture Celluclast as a representative for enzymes was investigated applying a fluorescent activity assay.

Conclusion

Microtiter plate-based high-throughput temperature profiling is a convenient tool for characterizing temperature dependent reaction processes. It allows the evaluation of numerous conditions, e.g. microorganisms, enzymes, media, and others, in a short time. The simple temperature control combined with a commercial on-line monitoring device makes it a user friendly system.

     

Optimization and modeling studies on the production of a new fibrinolytic protease using <Emphasis Type="Italic">Streptomyces radiopugnans</Emphasis>_VITSD8

Background

The current study demonstrated the possibility of statistical design tools combination with computational tools for optimization of fermentation conditions for enhanced fibrinolytic protease production.

Methods

The effects of using different carbon and nitrogen sources for protease production by Streptomyces radiopugnans_VITSD8 were examined by a full factorial design method. The incubation time, temperature, pH of the medium, and RPM were assessed by the predictable one factor at a time (OFAT) method. Optimization was carried out using starch and oat meal as carbon source, nitrogen source as peptic and malt extract using Fractional Factorial Design (FFD). The analysis was further continued for medium volume, temperature, initial medium pH, inoculum concentration, high determination co-efficient as (R’-0.965), and lower determination co-efficient of variation (CV-8.19%), which defines a reliable and accurate experimental value.

Results

Analysis of variance by the fixed slope effect by temperature and starch; temperature and L-aspargine, temperature and oat meal, temperature and peptic extracts, temperature and pH, temperature and duration of incubation were more vital for protease production at an interactive level. Response surface plots revealed that temperature, starch, and peptic extracts affix critical concerning in temperature. Programming estimated a 28% increase in protease production. Incubation temperature and medium volume portrayed extreme impact among all factor. Starch, peptic and temperature play an important regulatory role in protease production. Optimium temperature for protease production was 33°C. The ratio of carbon and nitrogen sources and pH were the major regulatory factors in protease production by Streptomyces radiopugnans_VITSD8. It demonstrated a 4% noteworthy change in condition.

Conclusion

Among all the selected parameters, temperature was the most intuitive factor, demonstrating a notable connection with the type of media and pH, while inoculum fixation had a direct impact on protein production.

     

The effects of temperature on bighorn population estimates in Yellowstone National Park

The effects of temperature on bighorn population estimates for Yellowstone National Park's Mt. Evert's winter range were examined. Based on work by Houston (1982), a bipartite relationship was hypothesized, whereby the effects of temperature upon the observability of sheep was predicted to be significantly different in those portions of the temperature spectrum where snowmelt occurs. Analyses of the regressions of bighorn numbers observed on mean daily ground temperature supported this hypothesis. At temperatures less than 0°C, counts increased significantly with temperature at a rate of 3.151, but were found to underestimate bighorn numbers and be unreliable as estimators of population trend. Counts conducted at 0° to 7°C increased with temperature at a significantly greater rate of 18.531. However, correction for population increases suggested this relationship reflected the intercorrelation of temperature and year; a result of selecting increasingly better census conditions over time. It was concluded that no additional benefit accrued from further increases in temperature once snowmelt occurred and that counts conducted at 0° to 7°C (the period between snowmelt and spring migration) were equally reliable. The importance of regarding snowmelt as a threshold value was underscored by the vastly different conclusions regarding bighorn population trends which have been drawn by different researchers from very nearly the same data. While previous research concluded that apparent population increases were the result of temperature-biased data, this study concluded that the apparently sigmoidal population growth was real.     

Time relationship between ambient temperature change and antigen stimulation on immune responses of mice

We investigated the time relationship between ambient temperature change and antigen stimulation on immune responses to sheep red blood cells (SRBC) and polyvinylpyrrolidone (PVP) in mice. In the case of a shift from comfortable (25°C) to cold (8°C) temperatures, suppression in the number of splenic plaque-forming cells (PFC) took place mainly when the shift was done between 1 day before and 2 to 4 days after immunization. The suppression of the PVP response lasted for up to a maximum of 6 days when mice were transferred 1 day before immunization. In the case of a temperature shift from 25° to 36.5°C, the suppressive effect was found when the temperature shift was done between 4 days before and 2 days after immunization. The effect lasted longer than that of the temperature shift to cold, i.e., at least 9 days after the temperature shift. Blood corticosterone levels after the temperature shifts corresponded to changes in the immune responses: elevation of the blood corticosterone levels was observed for only the first 3 days after a temperature shift to 8°C but for 10 days after a temperature shift to 36.5°C during the period time of the experiment. These result suggested that blood corticosterone level contributes to the duration of the effects of temperature shifts on immune responses of mice. Furthermore, it appeared that the early stage of the immune response is more susceptible to temperature shifts than the later stage. To explain these results, the terms effective period in the course of physiological adaptation to changed ambient temperature and susceptible period in the course of the immune response, were proposed.     

The temperature of the air within the external auditory meatus compared with esophageal temperature during anaesthesia and surgery

• 1.1.|Air temperature within the external auditory meatus, sensed by a thermistor insulated from the walls of the aural canal, was compared with the temperature recorded from a probe in the esophagus in patients under general anaesthesia.
• 2.2.|In the first study of 14 patients, aural temperatures at the time of induction of anaesthesia were more than 3°C lower, and the changes during surgery were more variable, than those recorded from the esophagus.
• 3.3.|In a second study of 35 patients in which heat loss from the external ear was reduced by ear protectors, there was also a poor correlation between temperatures of the ear and esophagus. Aural temperature was initially lower and rose over time in most cases whereas esophageal temperature generally decreased.
• 4.4.|These results suggest that air temperature within the aural canal is not a useful estimate of deep body temperature since it reflects mainly skin temperature.

     

Effect of temperature on the kinetics of the yeast AMP deaminase

• 1.1. The temperature dependence of the kinetics of the yeast AM P deaminase was examined using the purified enzyme and the permeabilized yeast cells.
• 2.2. The increase in the enzyme affinity for the substrate AMP was accompanied by the decrease in the maximal velocity with the decreasing temperature in the absence and presence of ATP.
• 3.3. The apparent Km for AMP was lowest at 15–20°C, and the affinity was decreased below and above this temperature.
• 4.4. The rate of the AMP deaminase reaction remained constant over a wide range of temperature in the presence of physiological AMP concentrations.
• 5.5. The temperature dependent change in kinetic properties of AMP deaminase may contribute to the control of the yeast glycolytic flux under the condition of lower temperature environments.

     

Kinetics of the Thermal Inactivation of Type E Clostridium botulinum Toxin

Rate of inactivation curves for the "free" toxin, prototoxin, or activated toxin in crude filtrates of Clostridium botulinum type E were nonlinear, consisting of a fast inactivating rate followed by a slow inactivating rate. Thermodynamic parameters were calculated over a temperature range of 125 to 145 F (51.7 to 62.8 C) for the two different inactivation rates. Energy of activation was low at the lower temperature and high at the higher temperature. The thermal requirement for inactivating similar concentrations of the "free" toxin, prototoxin, or activated toxin was considered to be the same.     

Small temperature differences can improve the performance of mesophilic sludge-based digesters

Objective

To assess the effect of small temperature increases in mesophilic sludge-based digesters in order to develop and evaluate strategies for improving the biogas production in full-scale digesters.

Results

Methane production was strongly affected by small temperature differences, and this result was consistent across samples from 15 full-scale digesters. The specific methane yield varied between 42 and 97.5 ml g VS^?1 after 15 days of incubation at 35 °C, and improved when increasing the digester temperature to 39 °C. Only a limited quantity of additional gas was required to balance out the cost of heating and a positive energy balance was obtained. Further increases in temperature, in some cases, negatively affected the production when operated at 42 °C compared to 39 °C.

Conclusions

Small temperature increases should be applied to mesophilic sludge-based digesters to optimize the biogas production and is applicable to digesters operated in the lower mesophilic temperature range.

     

Temperature regulation of oleate desaturase in sunflower (Helianthus annuus L.) seeds

The effect of temperature on oleate desaturation in developing sunflower (Helianthus annuus L.) seeds has been examined. When seeds from plants grown at low (20/10° C, day/night) temperature were transferred for 24 h to 10° C, an increase in the linoleate/oleate ratio in phosphatidylcholine and triacylglycerol was observed, but not when transfer was to 20 or 30° C. The same effect was observed in triacylglycerol, phosphatidylcholine and phosphatidylethanolamine in the newly synthesized lipids after in-vivo incubation with [1-¹⁴C]oleate at 10° C. The microsomal oleoyl phosphatidylcholine desaturase (ODS) activity of the seeds maintained at 10 C was also enhanced. The stimulation was observed after only 3 h in plants grown at high temperature (30/20° C). This effect was inhibited by cycloheximide, implying that the low-temperature stimulation of the ODS activity was caused by the synthesis of new enzyme. As a consequence, seeds from plants grown at low temperature had higher ODS activities and linoleate contents than those grown at high temperature. The microsomal ODS activity of seeds from plants grown at low temperature was dependent on incubation temperature and showed a maximum at 20° C. By contrast, this activity was almost temperature-insensitive in seeds from plants grown at high temperature. These results could explain how temperature regulates the fatty-acid composition in sunflower-seed lipids.Abbreviations DAF days after flowering - ODS oleoyl phosphatidylcholine desaturase - PC phosphatidylcholine - PE phosphatidylethanolamine - TAG triacylglycerol - 181 oleic acid - 182 linoleic acid To whom correspondence should be addressedThanks are due to M.C. Ruiz for skillful technical assistance. This work was supported by a grant from Junta de Andalucia, Spain.     

The development of thermoregulation in the marsupial brushtail possum Trichosurus vulpecula

• 1.1. The adult possums showed a circadian rhythm of body temperature with a peak in temperature around midnight and a nadir at noon.
• 2.2. The young possum within the pouch displayed a circadian rhythm with the highest temperatures during the day and the lowest in the early evening.
• 3.3. Although the body temperature of the young possum exceeded that of the mother occasionally, for the major part of the 24 hr the body temperature of the young was lower than that of the mother.
• 4.4. The young possum could maintain a steady body temperature between 140 and 167 days post partum. A circadian rhythm of temperature was observed between 157–190 days post partum.
• 5.5. All adipose tissue examined with the light and electron microscope had the morphology of white adipose tissue.

     

Collapse temperature of freeze-dried Lactobacillus bulgaricus suspensions and protective media

Optimization of the freeze-drying process needs to characterize the physical state of frozen and dried products. A protocol to measure the collapse temperature of complex biological media such as concentrated lactic acid bacteria using freeze-drying microscopy was first elaborated. Afterward, aqueous solutions of one or several components as well as concentrated lactic acid bacterial suspensions were analyzed in order to study how the structure of these materials is degraded during freeze-drying. A similar behavior toward collapse was observed for all aqueous solutions, which was characterized by two temperatures: the "microcollapse" temperature (T(microc), beginning of a local loss of structure) and the "collapse" temperature (T(c), beginning of an overall loss of structure). For aqueous solutions, these two temperatures were close, differing by less than 3 degrees C. Nevertheless, when lactic acid bacteria were added to aqueous solutions, the collapse temperatures increased. Moreover, the interval between microcollapse and collapse temperatures became larger. Lactic acid bacterial cells gave a kind of "robustness" to the freeze-dried product. Finally, comparing glass transition, measured by differential scanning calorimetry (DSC) and collapse temperature for aqueous solutions with noncrystallizable solutes, showed that these values belonged to the same temperature range (differing by less than 5 degrees C). As suggested in the literature, the glass transition temperature can thus be used as a first approximation of the collapse temperature of these media. However, for lactic acid bacterial suspensions, because the difference between collapse and glass transition temperatures was about 10 degrees C, this approximation was not justified. An elegant physical appearance of the dried cakes and an acceptable acidification activity recovery were obtained, when applying operating conditions during freeze-drying in vials that allowed the product temperature to be maintained during primary drying at a level lower than the collapse temperature of lactic acid bacterial suspensions. Consequently, the collapse temperature T(c) was proposed as the maximal product temperature preserving the structure from macroscopic collapse and an acceptable biological activity of cells.     

Effects of temperature and light on the composition of brackish-water rock pool ecosystems

I examined the effect of temperature and light on ecosystem composition was examined in a two factorial design using microcosms set up from natural rockpool communities. Furthermore I tested if the effect of temperature on different ecosystem components was dependent on the initial community composition by using communities from seven different rockpools that differed considerably in standing stocks of phytoplankton, zooplankton, zooplankton species composition, sediment mass and nutrient concentrations. Increased light caused phytoplankton biomass to decrease while zooplankton biomass and sediment dry weight was positively correlated to increased light levels. The effect of temperature on phytoplankon was largely determined by community type. Zooplankton biomass decreased with increasing temperature between 10°C and 25°C and this trend was not significantly different between different community types. A negative effect on zooplankton biomass was found at 7°C in one community. I propose, that the stronger temperature sensitivity of metabolical cost for herbivorous organisms compared to algae productivity might explain the decrease in zooplankton biomass at high temperatures. I discuss how edibility of algae and grazer characteristics may influence the response of ecosystem composition to temperature.     

The effect of ambient temperature on diurnal rhythm in heat production and activity in pigs kept in groups

The effect of ambient temperature on diurnal rhythm of metabolic rate and activity was studied in group housed pigs in two trials. Two climate controlled respiration chambers were used, one for each trial. Each chamber contained two groups of 8 pigs. During the experiment of 31 days the mean live weight of the animals increased from 28 to 40 kg. Feeding level was kept constant at 93 kg^–0.75. d^–1. Feed contained 12 kJ of metabolizable energy per g. Temperature treatment started with 20C for two days. After that it was lowered in stepwise fashion by 4K to 16, 12 and 8C. Each temperature treatment lasted two days. After that temperature it was increased in steps to 20C in 8 days. The whole procedure was repeated once. Metabolic rate and activity were measured continuously during the 24 hrs of every second day of the temperature treatment.Metabolic rate increased at temperatures below 16C. Activity was associated with ambient temperature. At low temperature, the total activity related heat production was increased, especially during day time. Variation in metabolic rate within a day was not reduced by low ambient temperature. Thermal requirement, calculated as lower critical temperature, was about 14C as averaged over the day, (16.1C during day time and 13.6C during night time). Extra thermal heat production below thermoneutrality was affected by time of day and activity.     

Micro- and macromethod assays for the ecological study of Legionella pneumophila

The survival of a strain of Legionella pneumophila (Lp-1) inoculated in artificial water microcosms was investigated with and without an amoebal host and varying environmental conditions, such as biofilm formation, amount of nutrients and incubation temperature. The results obtained using short (micromethod) and long (macromethod) term methods showed that L. pneumophila Lp-1 dies rapidly at 4 degrees C in the "macromethod" assay. When the same temperature (4 degrees C) was applied to the "micromethod" assay, L. pneumophila Lp-1 survived for three weeks, although it progressively decreased. At an incubation temperature of 30 degrees C, the aquatic environment was more favourable and better survival emerged in the "macromethod"; in contrast, this favourable temperature condition did not improve the survival of L. pneumophila Lp-1 cultured with the "micromethod". The role of the protozoa Acanthamoeba polyphaga proved to be indispensable for legionella survival only when environmental conditions become unfavourable.     

Pineal melatonin rhythms in the lizardAnolis carolinensis: effects of light and temperature cycles

Summary Pineal and ocular melatonin was assessed, over 24 h periods, in male lizards (Anolis carolinensis) entrained to 24 h light-dark (LD) cycles and a constant 32 C, and in lizards entrained to both 24 h LD cycles and 24 h temperature cycles (32 C/20 C). At a constant temperature, the duration of the photoperiod has a profound effect on the duration, amplitude, and phase of the pineal melatonin rhythm (Fig. 1). The pineal melatonin rhythm under cyclic temperature peaks during the cool (20 C) phase of the cycle regardless of whether or not the cool phase occurs during the light or dark phase of a LD 1212 cycle (Fig. 3). Under a temperature cycle and constant dim illumination, a pineal melatonin rhythm is observed which peaks during the cool phase of the temperature cycle, but the amplitude of the rhythm is depressed relative to that observed under LD (Fig. 2). Illumination up to 2 h in duration does not suppress the nocturnal melatonin peak in theAnolis pineal (Fig. 4). No melatonin rhythm was observed in the eyes ofAnolis under either 24 h LD cycles and a constant temperature (Fig. 1), or under simultaneous light and temperature cycles (Fig. 3). Ocular melatonin content was, in all cases, either very low or non-detectable.Abbreviations HIOMT hydroxyindole-O-methyltransferase - NAT N-acetyltransferase     

A low temperature microbial biosensor using immobilised psychrophilic bacteria

A psychrophilic bacteria, Deinococcus radiodurans, was used to construct a biosensor to be used in a flow injection system. The transducer used was an O₂ electrode. The response of this cell-based electrode was studied towards a number of sugars. The temperature dependence of the electrode response correlated well with the behavior of the cells. Thus, the optimum temperature for measurement of glucose (0.55 mM) was about +5°C. Since the organism used is psychrophilic, a response time at this low temperature is similar to what is achieved with mesophilic organisms at room temperature. This is the first biosensor constructed using a psychrophilic microorganism.