Increase In Central Temperature Research Articles

Development of multi-cross-linking, rapid curing, and easy cleaning, edible hydrogels for meat preservation

The design and development of a food preservation coating material with rapid curing and stable performance to shorten the coating process time and reduce quality changes caused by temperature fluctuations in cold chain is highly desirable in fresh meat preservation applications. In this study, a series of multi-cross-linked edible hydrogels were designed based on gelatin and k-carrageenan through the self-assembly triple-helix of gelatin and the potassium ion-mediated k-carrageenan double-helix structure. The tannic acid with phenolic hydroxyl groups was employed to enable the dynamic bond cross-linking between two polymers, endowing the composite hydrogel with rapid curing ability at low-temperature and a uniform molecular network structure. The hydrogel with a concentration of gelatin was 16% (GCBG-16) achieved the optimal combination properties, including 73.41% of elongation at break, 71.59 kJ/m2 of toughness, 27.73% of swelling ratio, and 50.73% of DPPH· scavenging rate. The hydrogels could be rapidly washed within 30 min at 40 °C by water, as well as possessing a certain self-healing and anti-freezing capabilities. The hydrogel GCBG-16 had a great capacity for protecting meat with a E value of 50.4 and 17.53 N of shear force even placed in a 37 °C environment, which showed no significant difference (p > 0.05) compared to the initial value. Furthermore, the fresh meats with coating showed delayed central temperature increase speed after leaving from the cold chain and placed in a 37 °C environment. The research results demonstrated that the proposed hydrogel has great potential in preserving fresh meat, which can serve as a matrix material combined with other active additives for extending the shelf life of meat products.

Some age-related features of intrauterine infection in premature infants

Annotation. The protective forces of newborns born prematurely, with low body weight under conditions of infection, are not capable of an adequate response. The aim of our study was to study some of the features of premature infants with low birth weight at the background of intrauterine infection. The first group consisted of 67 stories of premature babies born with low birth weight (LBW) from 1500 to 2500 g and gestational age 32–35 weeks (average gestational age — 34±2 weeks). It was revealed that a feature of the temperature homeostasis of children of group I is the establishment and maintenance of a temperature gradient, that is, the difference between central and peripheral temperatures, which ranged from 1,100 C to 1,500 C at the age of 6–7 days. It was found that the dynamics of the temperature gradient in the neonatal period is very often depended on the presence of perinatal pathology, namely, hypoxic-ischemic damage to the central nervous system. The regularities of temperature homeostasis in children of the second group are characterized, which amounted to 27 newborns with gestational age 38–40 weeks of gestation, birth weight 2600–3200 g without a clinic of respiratory disorders and neurological symptoms. On the 4th–5th day after birth, these children were discharged home under the supervision of a family doctor. In group II children who, after 1.5–2.5 months, were admitted to the neonatal pathology department diagnosed with acute respiratory viral infections: acute rhinopharyngitis or bronchitis, the temperature gradient ranged from 2.100 С to 3.500 С. In children, an increase in central temperature or a decrease in peripheral temperature was observed. It was found that with effective treatment on days 4–6, the temperature gradient was always constant and amounted to 1.500 С to 1.700 С. To identify the cause of the disease in the I and II groups, studies of blood, mucus from the pharynx and nose, and secretions from the trachea were performed. For this, we used the method of polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA) and bacteriological methods of research. The effect of intrauterine infection, the colonization of pathogenic intestinal microflora was evaluated, a low Apgar score of 1 and 5, the presence of respiratory disorders, hyporeflexia, a decrease in thymus, leukocytosis of more than 10 thousand, leukopenia of less than 4 thousand, neutrophilia with a shift to the left, which are very dangerous, were taken into account for premature babies and require respiratory support, colonization of the intestines with bifidobacterium and the use of immunocorrective therapy (venoimun at a dose of 0.4 ml / kg every other day for 3–5 days), which gives good results for nursing preterm infants.

Fine-scale spatial and temporal variation in temperature and arrhythmia episodes in the VA Normative Aging Study

ABSTRACTMany studies have demonstrated that cold and hot temperatures are associated with increased deaths and hospitalization rates; new findings indicate also an association with more specific cardiac risk factors. Most of these existing studies have relied on few weather stations to characterize exposures; few have used residence-specific estimates of temperature, or examined the exposure-response function. We investigated the association of arrhythmia episodes with spatial and temporal variation in temperature. We also evaluated the association btween monitored ambient temperature (central) and the same outcome. This longitudinal analysis included 701 older men participating in the VA Normative Aging Study. Arrhythmia episodes were measured as ventricular ectopy (VE) (bigeminy, trigeminy, or couplets episodes) by 4-min electrocardiogram (ECG) monitoring in repeated visits during 2000–2010. The outcome was defined as having or not VE episodes during a study visit. We applied a mixed-effect logistic regression model with a random intercept for subject, controlling for seasonality, weekday, medication use, smoking, diabetes status, body mass index, and age. We also examined effect modification by personal characteristics, confounding by air pollution, and the exposure-response function. For 1°C increase in the same day residence-specific temperature, the odds of having VE episodes was 1.10 (95% confidence interval [CI]: 1.04–1.17). The odds associated with 1°C increase in central temperature was 1.05 (95% CI: 1.02–1.09). The exposure-response function was nonlinear for averages of temperature, presenting a J-shaped pattern, suggesting greater risk at lower and higher temperatures. Increased warm temperature and decreased cold temperature may increase the risk of ventricular arrhythmias.Implications: This is the first study to provide evidence that residence-specific temperature exposure is associated with increased risk of ventricular arrhythmias in cohort of elderly subjects without known chronic medical conditions; that the delayed effect of temperature has a nonlinear relationship; and therefore that both warm and cold temperature increase the risk of having ventricular arrhythmias. Moreover, we show that the use of residence-specific temperature data reduces downward bias due to exposure error, by comparing the estimated health effect based on our spatiotemporal exposure prediction model to those based on a single local weather monitor.

Temperature and neuromuscular function

This review focuses on the effects of different environmental temperatures on the neuromuscular system. During short duration exercise, performance improves from 2% to 5% with a 1 °C increase in muscle temperature. However, if central temperature increases (i.e., hyperthermia), this positive relation ceases and performance becomes impaired. Performance impairments in both cold and hot environment are related to a modification in neural drive due to protective adaptations, central and peripheral failures. This review highlights, to some extent, the different effects of hot and cold environments on the supraspinal, spinal and peripheral components of the neural drive involved in the up- and down-regulation of neuromuscular function and shows that temperature also affects the neural drive transmission to the muscle and the excitation-contraction coupling.

Does the diurnal increase in central temperature interact with pre-cooling or passive warm-up of the leg?

Seven male subjects volunteered to participate in an investigation of whether the diurnal increase in core temperature influences the effects of pre-cooling or passive warm-up on muscular power. Morning (07:00-09:00h) and afternoon (17:00-19:00h) evaluation of maximal power output during a cycling sprint was performed on different days in a control condition (room at 21.8 degrees C, 69% rh), after 30min of pre-cooling in a cold bath (16 degrees C), or after 30min of passive warm-up in a hot bath (38 degrees C). Despite an equivalent increase from morning to afternoon in core temperature in all conditions (+0.4 degrees C, P<0.05), power output displayed a diurnal increase in control condition only. A local cooling or heating of the leg in a neutral environment blunted the diurnal variation in muscular power. Because pre-cooling decreases muscle power, force and velocity irrespective of time-of-day, athletes should strictly avoid any cooling before a sprint exercise. In summary, diurnal variation in muscle power output seems to be more influenced by muscle rather than core temperature.

Effects of Active Warm-up and Diurnal Increase in Temperature on Muscular Power

To investigate the effects of both an active warm-up (AWU) and the diurnal increase in body temperature on muscular power. Eight male subjects performed maximal cycling sprints in the morning (7:00-9:00 a.m.) and afternoon (5:00-7:00 p.m.) either after an AWU or in a control condition. The AWU consisted of 12 min of pedaling at 50% of & OV0312;O2 max inter-spersed with three brief accelerations of 5 s. Rectal temperature, maximal force developed during the cycling sprint, and muscular power were higher in the afternoon than in the morning (P<0.05). Rectal temperature, calculated muscular temperature, and muscular power were higher after AWU than in control condition (P<0.05). The beneficial effect of an AWU can be combined with that of the diurnal increase in central temperature to improve muscular power.

The Internal Structural Adjustment Due to Tidal Heating of Short‐Period Inflated Giant Planets

Several short-period Jupiter-mass planets have been discovered around nearby solar-type stars. During the circularization of their orbits, the dissipation of tidal disturbance by their host stars heats the interior and inflates the sizes of these planets. Based on a series of internal structure calculations for giant planets, we examine the physical processes which determine their luminosity-radius relation. In order for young or intensely heated gas giant planets to attain quasi-hydrostatic equilibria, with sizes comparable to or larger than two Jupiter radii, their interiors must have sufficiently high temperature and low density such that degeneracy effects are relatively weak compared to those in a mature and compact Jupiter. Consequently, the polytropic index monotonically increases whereas the central temperature increases and then decreases with the planets' size. These effects, along with a temperature-sensitive opacity for the radiative surface layers of giant planets, cause the power index of the luminosity's dependence on radius to decrease with increasing radius. For planets larger than twice Jupiter's radius, this index is sufficiently small that they become unstable to tidal inflation. We make comparisons between cases of uniform heating and cases in which the heating is concentrated in various locations within the giant planet. Based on these results we suggest that accurate measurement of the sizes of close-in young Jupiters can be used to probe their internal structure under the influence of tidal heating.

Oxygen consumption after cardiopulmonary bypass surgery in children: Determinants and implications

Objective: We sought to assess oxygen consumption and its determinants in children shortly after undergoing cardiopulmonary bypass operations. Methods: Twenty children, aged 2 months to 15 years (median, 3.75 years), undergoing hypothermic cardiopulmonary bypass operations were studied during the first 4 hours after arrival in the intensive care unit. Central and peripheral temperatures were monitored. Oxygen consumption was continuously measured by using respiratory mass spectrometry. Oxygen delivery was calculated from oxygen consumption and arterial and mixed venous oxygen contents, which were sampled every 30 minutes. Oxygen extraction was derived by the ratio of oxygen consumption and oxygen delivery. Arterial blood lactate levels were measured every 30 minutes. Results: There was a correlation between oxygen consumption and age in patients older than 3 months (r = –0.76). Mean oxygen consumption increased by 14.7% during the study. The increase in oxygen consumption was correlated with the increase in central temperature (r = 0.73). Nine patients had an arterial lactate level above 2 mmol/L on arrival. There were no significant differences in oxygen consumption, oxygen delivery, and oxygen extraction between the group with lactate levels between 2 and 3 mmol/L and the groups with normal lactate levels both on arrival and at 2 hours. One patient with a peak lactate level of 6.8 mmol/L had initially low oxygen delivery (241.3 mL · min–1 · m–2). Conclusions: During the early hours after a pediatric cardiac operation, the increase in oxygen consumption is mainly attributed to the increase in central temperature. Oxygen consumption is negatively related to age. Mild lactatemia is common and does not appear to reflect oxygen delivery or oxygen consumption or a more complicated recovery. (J Thorac Cardiovasc Surg 2000;119:525-33)

Dynamics and topography of human temperature regulation in response to thermal and work load.

Climatic chamber experiments were carried out with male subjects who were submitted to various rapid temperature changes. All experiments were performed first with the subjects at rest and later at work on a bicycle ergometer. The aims of the study were to obtain quantitative data enabling to determine effects of abrupt thermal load, abrupt work load, and combined load on the topography and the dynamics of temperatures and effectors, and to answer the question whether the effects of combined load may be computed by a linear superposition of pure thermal plus pure work load. Skin temperatures generally respond more directly to abrupt changes of thermal than of work load. This is in contrast to the dynamic behaviour of central temperatures which moreover exhibit the interesting effect of a transient paradoxical response both to the onset of work and of thermal load. Time constants of the dynamics of metabolic heat production are high in response to changes of thermal load as compared to the time constants at the onset and end of work. Generally the time constants of skin temperatures are shorter at rest than at work. Temperature topography changes only to a small extent in exercising subjects. The central temperature increase to combined thermal and work load is not significantly different from the added amount of temperature increases due to pure thermal and to pure work load. This suggests a quasi-linear superposition of both thermal effects and confirms, in accordance with further evidence of this and former studies, the hypothesis that work load does not interfere non-linearly with the regulatory processes.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary results of electron cyclotronheating experiments on the PDX Tokamak

ECH experiments on PDX have been carried out with two 60GHz pulsed gyrotrons at about l00kWeach. The electron cyclotron (EC) waves were launched in narrow beams from both outside andinside the plasma torus. In the best heating results obtained, Thomson scattering datarecorded a central temperature increase from ⩽1.5keV to ⩽2.5keV at about 1O13cm-3 density withapproximately 80kW outside ordinary mode heating.

Investigation of Radial Plutonium Redistribution in Mixed Oxide Fuels Irradiated in a Fast Flux

Redistribution of plutonium has been examined in three hypostoichiometric mixed oxide fuel pins irradiated in the fast flux of the RAPSODIE reactor. From the results of these examinations, the effective heat of transport of thermal diffusion of plutonium is estimated. The increase in central temperature is determined with plutonium distributions calculated from thermal diffusion and estimated from postirradiation examinations, respectively. In stoichiometric fuels, a temperature increase of up to 150°C must be anticipated due to plutonium enrichment by evaporation-condensation processes, while in strongly hypostoichiometric fuels the increase in central temperature, caused in this case by thermal diffusion, does not exceed 50°C for power ratings below 450 W/cm. The radial variation of the O/(U +Pu) ratio is calculated since it strongly influences the vapor pressures of the fuel component species and therefore influences the redistribution by evaporation-condensation processes.

Evolution of Carbon Stars. I

The evolution of carbon-oxygen stars in a gravitational contraction phase is studied with an automatic computation method for the stellar masses 0.7M⊙, 1.0M⊙, 2.6M⊙ and 10M⊙. These stars are regarded as representing the carbon-oxygen cores which have been formed in evolved stars in helium-burning phase. To know the effect of neutrino loss on the evolution, computations are made for the two alternative cases, i. e. the cases with and without neutrino production. It is found that, if nuclear burning is neglected, the central temperature increases unlimitedly for the stars of 2.6M⊙ and 10M⊙, while it has an upper limit due to the onset of electron degeneracy for the stars of 0.7M⊙ and 1.0M⊙. The neutrino les suppresses the increase of the central temperature and reduces the time-scale of contraction. The onset stage of carbon burning and the subsequent transition to the zero-age carbon main-sequence stage are computed. The minimum stellar mass for this onset is found to be 0.75M⊙ for the case without neutrinos and 1.06M⊙ for the case with neutrinos.

Evolution of a Star with Intermediate Mass after Hydrogen Burning. I

The evolution of a population I star of 4 M/sub sub solar /, after the formation of a dehydrogenized core and a hydrogen burning shell, is calculated up to the stage when helium has almost burnt out in the central region. This course of the evolution is divided into three phases. In the first phase, the star has a hydrogen-burning shell and an isothermal core, and 2.1 x 10/sup 6 years, until the mass fraction of the core grows to 0.120 beyond which there exists no solution with an isothermal core. In the second phase, the core of the star contracts rapidly releasing gravitational energy while the envelope expands. The central temperature increases and the star comes to the red giant region in 1.1 x 10/sup 6/ years before helium begins to burn. In this course electrons do not become degenerate and 4 M/sub sub solar / is found to be near a critical stellar mass devoid of the formation of a degenerate isothermal core. Finally, in the phase of helium burning, the core expands and the envelope shrinks slowly until the helium content in the central region decreases to 0.3. Afterwards the envelope expands again. The lifetime of themore » helium burning phase is 2.1 x 10/sup 7/ years and the star spends half of this time as an A-type giant near the turning point. Effects of uncertainties in nuclear energy generation rates, opacities, and chemical compositions on the structure of this A-type giant are examined. Even if these uncertainties are taken into account, a separate group of A-type giants in the HerzsprungRussell diagram of NGC 458 can be identified with the helium-burning phase. The observed number of these stars is consistent with the calculated lifetime. (auth)« less