Gradually decreasing temperature
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V štúdií, porovnávajúcej zmeny teploty tela počas epidurálnej (20pacientov) a celkovej anestézie (20 pacientov), bolo zaradených 40 dospelých pacientov pripravovaných na vaskulárny,res. ortopedický výkon dolnej končatiny. Teplotné záznamy boli získané z tympanickej membrány ucha a axily a boli zanamenávané predoperačne, inheď po úvode do anestézie a v 20-min. intervaloch počas prvých troch hodín výkonu. Teploty tela na dvoch miestach merania postupne klesali podobným spôsobom u oboch skupín pacientov. Na konci tretej hodiny od nástupu anestézie tympanická a axilárna teplota v skupine epidurálnej anestézie klesla o -1,06 ˚C ± 0,12 (p < 0,01) a -1,01 °C ± 0,14 (p < 0,01). V skupine celkovej anestézie tympanická teplota klesla o -1,04 °C ± 0,31 (p < 0,01) a axilárna o -0,94 °C ± 0,25 (p < 0,01). Pri porovnaní identických miest merania v týchto dvoch skupinách sa v danom časovom horizonte signifikantne nelíšili teploty tympanické od axilárnych. V každej skupine boli axilárne merania signifikantne nižšie ako tympanické vo všetkých intervaloch (priemerné rozdiely medzi dvomi miestami boli 0,31 °C ± 0,07 u epidurálnej anestézie a 0,28 °C ± 0,04 u celkovej anestézie) s priemerným korelačným koeficientom 0,91 ± 0,02 pre epiduraálnu anestéziu a 0,77 ± 0,12 pre celkovú anestéziu. Z toho usudzujeme, že pacienti podrobení dlhodobému periférnemu chirurgickému výkonu majú rovnaké riziko vzniku peroperačnej hypotermie počas epidurálnej ako aj celkovej anestézie, a preto je nevyhnutné peroperačne monitorovať teplotu tela bez ohľadu na typ anestézie.
Forty adult patients of two groups scheduled for vascular and orthopedic surgery of the lower extremities were enrolled in a study comparing body temperature changes under either epidural (EA, 20 patients) or general (GA, 20 patients) anesthesia.Temperature recordings were obtained from tympanic membrane (TM) and were collected preoperatively,immediately after induction in anesthesia and then at twenty-min intervals for the first three hours of surgery. Body temperatures at the two measurement sites were decreased gradually throughout the studied period in a similar pattern in both groups of patients. At the end of the third hour after induction in anesthesia, tympanic and axillary temperatures in the EA group were decreased by -1.06 °C ± 0.12 (P < 0.01) and -1.01 °C ± 0.14 (P < 0.01) respectively.In the GA group the corresponding decreases were -1.04 °C ± 0.31 (P < 0.01) and -0.94 °C ± 0.25 (P < 0.01). Comparing the corresponding measurement sites of the two groups, neither tympanic nor axillary temperatures were differed significantly at any time period. Within each of the groups, axillary measurements were significantly lower than the tympanic measurements at all intervals (mean differences between the two measurement sites were 0.32 °C ± 0.07 and 0.28 °C ± 0.04 in the EA and GA groups respectively), and had an average correlation coefficients of 0.91 ± 0.02 and 0.77 ± 0.12 respectively. We concluded that, patients undergoing prolonged peripheral surgical procedures are at the same risk of developing intraoperative hypothermia under epidural or general anesthesia, therefore, perioperative body temperature should be monitored properly regardless to the type of anesthesia.
- MeSH
- celková anestezie MeSH
- dospělí MeSH
- hypotermie diagnóza MeSH
- lidé středního věku MeSH
- lidé MeSH
- peroperační monitorování MeSH
- riziko MeSH
- senioři MeSH
- svodná anestezie MeSH
- tělesná teplota MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- srovnávací studie MeSH
It has been verified under laboratory conditions that constant and changing water temperature markedly affects the micropopulation growth in Gyrodactylus gobiensis parasite on the body surface of gudgeons (Gobio gobio L.). At a water temperature of 12 degrees C, the number of gyrodactylids gradually increased up to the mean value of 63 specimens per host, which was reached on days 27-28 after experimental infection. At a constant temperature of 18 degrees C, the parasites completely disappeared from the bodies of infected fishes on days 15-20 p.i. A similar effect was produced by gradually increasing temperature from 12 to 18 degrees C, while the decrease in water temperature from 18 to 12 degrees C resulted in an increase in the parasite number.
- MeSH
- Cestoda růst a vývoj MeSH
- cestodózy parazitologie veterinární MeSH
- infestace ektoparazity parazitologie veterinární MeSH
- nemoci ryb parazitologie MeSH
- ryby MeSH
- sladká voda * MeSH
- teplota MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Československo MeSH
Diurnal courses of photosynthetic gas exchange parameters, chlorophyll a fluorescence characteristics and the de-epoxidation state of the xanthophyll cycle pigments (DEPS) were measured during the gradual acclimation of 4-year-old Norway spruce seedlings to different photosynthetic photon flux density (PPFD) and air temperature (T(air)) regimes, simulating cloudy days with moderate T(air) (LI, maximum PPFD 300 micromol m(-2)s(-1), T(air) range 15-25 degrees C), sunny days with moderate T(air) (HI, maximum PPFD 1000 micromol m(-2)s(-1), T(air) range 15-25 degrees C) and hot sunny days (HI-HT, maximum PPFD 1000 micromol m(-2)s(-1), T(air) range 20-35 degrees C). The plants were acclimated inside a growth chamber and each acclimation regime lasted for 13d. Acclimation to HI conditions led to a strong depression of the net CO(2) assimilation rates (A(N)), particularly during noon and afternoon periods. Exposure to the HI-HT regime led to a further decrease of A(N) even during the morning period. Insufficient stomatal conductance was found to be the main reason for depressed A(N) under HI and HI-HT conditions. Only slight changes of the maximum photosystem II (PSII) photochemical efficiency (F(V)/F(M)), in the range of 0.78-0.82, supported the resistance of the Norway spruce photosynthetic apparatus against PSII photoinhibition during acclimation to both HI and HI-HT conditions. The HI plants showed increased content of xanthophyll cycle pigments (VAZ) and enhanced efficiency of thermal energy dissipation within PSII (D) that closely correlated with the increased DEPS. In contrast, acclimation to the HI-HT regime resulted in a slight reduction of VAZ content and significantly diminished D and DEPS values during the entire day in comparison with HI plants. These results indicate a minor role of the xanthophyll cycle-mediated thermal dissipation in PSII photoprotection under elevated temperatures. The different contributions of the thermal dissipation and non-assimilatory electron transport pathways in PSII photoprotection during acclimation of the Norway spruce photosynthetic apparatus to excess irradiance and heat stresses are discussed.
- MeSH
- aklimatizace účinky záření MeSH
- chlorofyl metabolismus MeSH
- cirkadiánní rytmus účinky záření MeSH
- fotony MeSH
- fotosyntéza účinky záření MeSH
- fotosystém II (proteinový komplex) metabolismus MeSH
- oxid uhličitý metabolismus MeSH
- plyny metabolismus MeSH
- průduchy rostlin fyziologie účinky záření MeSH
- smrk fyziologie účinky záření MeSH
- světlo MeSH
- teplota MeSH
- xanthofyly metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Norsko MeSH
With an increasing focus on sustainable technologies in the pharmaceutical industry, milling provides a solvent-free approach to improve drug dissolution. Milling of drugs with an excipient offers additional opportunities to achieve supersaturation kinetics. Therefore, this work aims to present insights of co-milling fenofibrate and apremilast, two good glass formers with low and high glass transition temperatures (Tgs) respectively. Drugs were co-milled with croscarmellose sodium for various process durations followed by thermal analysis, investigation of crystallinity, surface area and dissolution. The dissolution enhancement of the low-Tg glass former fenofibrate highly correlated with the process-induced increase in surface area of co-milled systems (R2 = 0.96). In contrast, the high-Tg glass former apremilast lost its crystalline order gradually after ≥ 10 min of co-milling, and favourable supersaturation kinetics during biorelevant dissolution testing were observed. Interestingly, the melting point of co-milled apremilast decreased and linearly correlated with the highest measured drug concentration (cmax) during in vitro dissolution (onset temperature R2 = 0.98; peak temperature R2 = 0.96). The melting point depression remained stable after 90 days for apremilast, whereas fenofibrate co-milled for 20 min or more showed an increase in melting point upon storage. This study demonstrated that co-milling with croscarmellose sodium is ideally suited to good glass formers with a high Tg. The melting point depression is thereby proposed as an easily accessible critical quality attribute to estimate likely dissolution performance of drugs in dry co-milled formulations.
Despite poisoning with the ecstasy substitute para-methoxymethamphetamine (PMMA) being typically associated with severe hyperthermia and death, behavioral and toxicological data on this drug are missing. Herein we present the behavioral profile of PMMA, its hyperthermic potency and pharmacokinetic profile in rats. The effects of PMMA 5 and 20 mg/kg on locomotion, on prepulse inhibition (PPI) of acoustic startle reaction (ASR), on body temperature under isolated and crowded conditions and on the pharmacokinetics analyzed with gas chromatography mass spectrometry (GC-MS) were evaluated. PMMA increased overall locomotion with the higher dose showing a biphasic effect. PPI was decreased dose-dependently. The hyperthermic response was present only with PMMA 20 mg/kg and was accompanied by extensive perspiration under crowded conditions. Serum levels of PMMA peaked at approximately 30 min after both treatments; on the contrary the maximum brain concentrations of PMMA at 20 mg/kg peaked approximately 1h after the administration, which was rather delayed compared to maximum after 5mg/kg dose. These data indicate that PMMA has a similar behavioral profile to stimulants and hallucinogens and that the toxicity might be increased in a crowded environment. High doses of PMMA have a gradual penetration to the brain which might lead to the delayed peak concentrations and prolonged effects of the drug.
- MeSH
- chování zvířat účinky léků MeSH
- horečka chemicky indukované MeSH
- krysa rodu rattus MeSH
- methamfetamin aplikace a dávkování analogy a deriváty farmakokinetika toxicita MeSH
- modely u zvířat MeSH
- mozek účinky léků metabolismus MeSH
- pohybová aktivita účinky léků MeSH
- potkani Wistar MeSH
- psychotropní léky aplikace a dávkování farmakokinetika toxicita MeSH
- tělesná teplota účinky léků MeSH
- úleková reakce účinky léků MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A pilot scale gasification unit with novel co-current, updraft arrangement in the first stage and counter-current downdraft in the second stage was developed and exploited for studying effects of two stage gasification in comparison with one stage gasification of biomass (wood pellets) on fuel gas composition and attainable gas purity. Significant producer gas parameters (gas composition, heating value, content of tar compounds, content of inorganic gas impurities) were compared for the two stage and the one stage method of the gasification arrangement with only the upward moving bed (co-current updraft). The main novel features of the gasifier conception include grate-less reactor, upward moving bed of biomass particles (e.g. pellets) by means of a screw elevator with changeable rotational speed and gradual expanding diameter of the cylindrical reactor in the part above the upper end of the screw. The gasifier concept and arrangement are considered convenient for thermal power range 100-350 kW(th). The second stage of the gasifier served mainly for tar compounds destruction/reforming by increased temperature (around 950°C) and for gasification reaction of the fuel gas with char. The second stage used additional combustion of the fuel gas by preheated secondary air for attaining higher temperature and faster gasification of the remaining char from the first stage. The measurements of gas composition and tar compound contents confirmed superiority of the two stage gasification system, drastic decrease of aromatic compounds with two and higher number of benzene rings by 1-2 orders. On the other hand the two stage gasification (with overall ER=0.71) led to substantial reduction of gas heating value (LHV=3.15 MJ/Nm(3)), elevation of gas volume and increase of nitrogen content in fuel gas. The increased temperature (>950°C) at the entrance to the char bed caused also substantial decrease of ammonia content in fuel gas. The char with higher content of ash leaving the second stage presented only few mass% of the inlet biomass stream.
BACKGROUND: Adjusting the timing of annual events to gradual changes in environmental conditions is necessary for population viability. However, adaptations to weather extremes are poorly documented in migratory species. Due to their vast seasonal movements, long-distance migrants face unique challenges in responding to changes as they rely on an endogenous circannual rhythm to cue the timing of their migration. Furthermore, the exact mechanisms that explain how environmental factors shape the migration schedules of long-distance migrants are often unknown. RESULTS: Here we show that long-distance migrating semi-collared flycatchers Ficedula semitorquata delayed the last phase of their spring migration and the population suffered low return rates to breeding sites while enduring a severe cold spell en route. We found that the onset of spring migration in Africa and the timing of Sahara crossing were consistent between early and late springs while the arrival at the breeding site depended on spring phenology at stopover areas in each particular year. CONCLUSION: Understanding how environmental stimuli and endogenous circannual rhythms interact can improve predictions of the consequences of climate changes on migratory animals.
- MeSH
- migrace zvířat * MeSH
- nízká teplota MeSH
- podnebí MeSH
- roční období MeSH
- zpěvní ptáci fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Adults of warm- and cold-acclimated tropical cockroaches, Nauphoeta cinerea were exposed to low temperatures of 0 or 5 degrees C for various time intervals (hours to days). Development of chilling-injury (defects in crawling and uncoordinated movements) and mortality during the exposure were assessed and correlated with the changes in concentrations of metal ions (Na(+), K(+) and Mg(2+)) in the haemolymph and coxal muscle tissue. Warm-acclimated insects entered chill-coma at both low temperatures. In their haemolymph, the [Na(+)] and [Mg(2+)] linearly decreased and [K(+)] increased with the increasing time of exposure. The rate of concentration changes was higher at 0 than at 5 degrees C. The concentration changes resulted in gradually dissipating equilibrium potentials across the muscle cell membranes. For instance, E(K) decreased from -49.8 to -20.7 mV during 7 days at 5 degrees C. Such a disturbance of ion homeostasis was paralleled by the gradual development of chilling-injury and mortality. Most of the cockroaches showed chilling-injury when the molar ratio of [Na(+)]/[K(+)] in their haemolymph decreased from an initial of 4.4 to 2.1-2.5. In contrast, the cold-acclimated cockroaches did not enter chill-coma. They maintained constant concentrations of ions in their haemolymph, constant equilibrium potentials across muscle cell membranes and the development of chilling-injury was significantly suppressed at 5 degrees C for 7 days.
Gradual heating of green leaves up to non-physiological temperatures is often used to estimate thermal stability of photosynthetic apparatus. However, a complete sequence of heat-induced disassembly and denaturation of chlorophyll-containing protein complexes (CPCs) has not been reported yet. In this work, we heated (1 degrees C x min(-1)) barley leaves to temperatures selected according to the changes in the chlorophyll fluorescence temperature curve (FTC) and we analyzed CPC stability by two-dimensional native Deriphat/SDS-PAGE. The first distinct change in both structure and function of photosystem II (PSII) appeared at 40-50 degrees C. PSII core (CCII) dimers began to dissociate monomers, which was accompanied by a decrease in PSII photochemistry and reflected in FTC as the first fluorescence increase. Further changes in CPCs appeared at 57-60 degrees C, when FTC increases to its second maximum. Photosystem I (PSI) cores (CCI) partially dissociated from light-harvesting complexes of PSI (LHCI) and formed aggregates. The rest of CCI-LHCI complexes, as well as the CCI aggregates, degraded to the PSI-A/B heterodimer in leaves heated to 70 degrees C. Heating to these temperatures led to a complete degradation of CCII components and corresponding loss of PSII photochemistry. Trimeric light-harvesting complexes of PSII (LHCII) markedly dissociated to monomers and denatured, as evidenced by a release of large amount of free chlorophylls. Between 70 and 80 degrees C, a complete degradation of LHCII occurred, leaving the PSI-A/B heterodimer as the only detectable CPC in the membrane. This most thermostable CPC disappeared after heating to 90 degrees C, which corresponded to a loss of PSI photochemistry.
- MeSH
- biologické pigmenty analýza MeSH
- chlorofyl analýza MeSH
- fotosyntéza MeSH
- ječmen (rod) metabolismus MeSH
- listy rostlin chemie metabolismus účinky záření MeSH
- molekulová hmotnost MeSH
- světlo MeSH
- světlosběrné proteinové komplexy chemie metabolismus MeSH
- termodynamika MeSH
- tylakoidy chemie MeSH
- vysoká teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The effect of two types of modified atmosphere (MA1: 69% N2, 25% CO2, 5% O2, 1% CO; MA2: 70% N2, 30% CO2) on changes in physical and chemical parameters (pH, a(w)--water activity, TVBN - total volatile basic nitrogen, TMA - trimethylamine, FFA - free fatty acids, PV - peroxide value, TBA--thiobarbituric acid) in muscle tissues of the silver carp was monitored in the study. The samples were stored at temperatures +2 +/- 2 degrees C for 18 days. Changes in gas volumes (CO2 and O2) in MAs were also monitored. CO2 levels increased in MA1 but decreased in MA2. At the end of 18 days of storage, a significantly (P < 0.01) lower water activity (a(w)) levels were found in samples packaged under MA1, in contrast to samples packaged under MA2 where water activity values showed considerable fluctuation. Variations in pH values in the two types of MA showed similar trends. Sample pH gradually decreased until day 9 of storage. On day 11, muscle tissue pH increased markedly and then began to decrease again. The overall decrease in pH values was more profound in samples packaged under MA1. TVBN and TMA levels in samples packaged under the two types of MAs remained almost identical until day 9 of the experiment. Later, however, significantly (P < 0.01) higher levels of both parameters were found in muscle tissues packaged under MA1. FFA concentrations in silver carp samples in MA1 were significantly lower (P < 0.01) throughout the experiment. The PV increased significantly in both muscle samples tested. Greater fluctuations in this parameter's values throughout the experiment were observed in samples packaged under MA2. Faster rates of oxidation (P < 0.01) were found in samples packaged under MA1 starting on day 9. Maximum TBA values in MA1 and MA2 were observed on days 14 and 18 of the experiment, respectively. From the course of proteolytic and oxidative changes point of view, the more appropriate combination of gases for silver carp storage seems to be the mixture of 70% N2 and 30% CO2 (MA2), which allows for muscle storage of up to 9 days. We recommend TVBN as a suitable indicator of freshness, and TBA assay as a suitable indicator of the extent of oxidative processes.
- MeSH
- atmosféra MeSH
- časové faktory MeSH
- kapři MeSH
- kosterní svaly MeSH
- maso normy MeSH
- nízká teplota MeSH
- obaly potravin metody MeSH
- skladování potravin MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH