Increase Of tCo Research Articles

Can the inner eye canthus temperature be used as an alternative method to measure core temperature in sleep-deprived individuals?

Core temperature is used in several situations, including studies on biological rhythms and circadian markers of physical performance. Measuring the inner eye canthus (Tco) temperature is a method proposed to identify core temperature, but it has shown little concordance in physical exercise situations and has not yet been used in studies with measurements taken throughout the day. The objective of this study was to compare the measurements and daily behavior of Tco obtained by infrared thermography with rectal temperature (Tre) during a prolonged waking protocol. Eleven male individuals participated in the study, who remained in the laboratory for at least 38 h using an actigraph to determine the wakefulness time and were monitored during the entire period. The Tre and Tco measurements were performed every 3 h. The ANOVA was used for repeated measurements followed by Bonferroni’s post-hoc test to find the limits of concordance/proximity, while the Bland and Altman method and the Intraclass Correlation Coefficient were used to establish the reliability between the pairs. The significance level adopted was p < 0.05. The results demonstrate significant differences, low levels of concordance and unsatisfactory reliability levels between Tco and Tre at all 13 analyzed moments, in addition to not showing measurement reliability when all data are used together with the 143 temperature measurements. Daily behavior analysis shows moments with similar behavior with an increase in Tco and Tre, but at other times the behavior was the opposite, with a decrease in one measurement and an increase in the other. Based on the results presented, it is not recommended to use the inner eye canthus temperature as a substitute for rectal temperature for measuring core temperature at different times of the day or in sleep-deprived individuals.

Transcutaneous Oximetry Does Not Reliably Predict Wound-healing Complications in Preoperatively Radiated Soft Tissue Sarcoma.

Surgical wound-healing complications after tumor resections in tissue that has been preoperatively radiated are a major clinical problem. Most studies have reported that complications occur in more than 30% of patients undergoing such resections in the lower extremity. There is currently no available method to predict which patients are likely to have a complication. Transcutaneous oximetry has been identified in preliminary studies as potentially useful, but the available evidence on its efficacy for this application thus far is inconclusive. (1) Does transcutaneous oximetry measurement below 25 mmHg at any location in the surgical wound bed predict a wound-healing complication? (2) Does recovery (increase) in transcutaneous oxygen measurement during the rest period between the end of radiation and the time of surgery protect against wound-healing complications? A prospective, multi-institution study was coordinated to measure skin oxygenation at three timepoints in patients undergoing surgery for a lower extremity soft tissue sarcoma after preoperative radiation. Between 2016 and 2020, the five participating centers treated 476 patients for lower extremity soft tissue sarcoma. Of those, we considered those with a first-time sarcoma treated with radiation before limb salvage surgery as potentially eligible. Based on that, 21% (98 of 476) were eligible; a further 12% (56 of 476) were excluded because they refused to participate or ultimately, they were treated with a flap, amputation, or skin graft. Another 1% (3 of 476) of patients were lost because of incomplete datasets or follow-up less than 6 months, leaving 8% (39 of 476) for analysis here. The mean patient age was 62 ± 14 years, 62% (24 of 39) of the group were men, and 18% (7 of 39) of patients smoked cigarettes; 87% (34 of 39) of tumors were intermediate/high grade, and the most common histologic subtype was undifferentiated pleomorphic sarcoma. In investigating complications, a cutoff of 25 mmHg was chosen based on a pilot investigation that identified this value. All patients were assessed for surgical wound-healing complications, which were defined as: those resulting in a return to the operating room, initiation of oral or IV antibiotics, intervention for seroma, or prolonged wound packing or dressing changes. To answer the first research question, we compared the proportion of patients who developed a wound-healing complication between those patients who had any reading below 25 mmHg (7 of 39) and those who did not (32 of 39). To answer the second question, we compared the group with stable or decreased skin oxygenation (22 of 37 patient measurements [two patients missed the immediate postoperative measurement]) to the group that had increased skin oxygen measurement (15 of 37 measurements) during the period between the end of radiation and the surgical procedure; again, the endpoint was the development of a wound-healing complication. This study was powered a priori to detect an unadjusted odds ratio for wound-healing complications as small as 0.71 for a five-unit (5 mmHg) increase in TcO 2 between the groups, with α set to 0.05, β set to 0.2, and a sample size of 40 patients. We found no difference in the odds of a wound-healing complication between patients whose transcutaneous oxygen measurements were greater than or equal to 25 mmHg at all timepoints compared with those who had one or more readings below that threshold (odds ratio 0.27 [95% confidence interval (CI) 0.05 to 1.63]; p = 0.15). There was no difference in the odds of a wound-healing complication between patients who had recovery of skin oxygenation between radiation and surgery and those who did not (OR 0.63 [95% CI 0.37 to 5.12]; p = 0.64). Transcutaneous oximetry cannot be considered a reliable test in isolation to predict wound-healing complications. This may be a function of the fact that transcutaneous oximetry samples a relatively small portion of the landscape in which a wound-healing complication could potentially arise. In the absence of a reliable diagnostic test, clinicians must still use their best judgment regarding surgical timing and work to address modifiable risk factors to avoid complications. The unanswered question that remains is whether there is a skin perfusion or oxygenation issue at the root of these complications, which seems likely. Alternative approaches that can assess the wound more broadly and in real time, such as fluorescent probes, may be deserving of further investigation. Level II, diagnostic study.

Попередження інтраопераційної ненавмисної гіпотермії у пацієнтів із політравмою

Актуальність. Ненавмисна гіпотермія розвивається спонтанно як наслідок травми, хірургічного втручання та наркозу в результаті порушення відповідності теплопродукції тепловтрат і пригнічення компенсаторної терморегуляційної відповіді. Мета: вивчити ефективність способу корекції інтраопераційної ненавмисної гіпотермії з використанням системи конвекційного обігріву в пацієнтів із політравмою. Матеріали та методи. Обстежено 20 пацієнтів із політравмою, яким проводились ургентні оперативні втручання. Пацієнти були розділені на 2 групи: I — основна група (n = 10), в якій інтраопераційно проводилося активне зігрівання системою конвекційного обігріву WarmAir 135 (CSZ) з використанням ковдр для зігрівання в умовах операційної; II — контрольна група (n = 10) без використання конвекційного зігрівання. Вивчалася температура ядра тіла (Тсо): початково, через 30, 60 хвилин і наприкінці операції. Розраховувалися наступні показники: мінімальна (Тмін.) і максимальна (Тмакс.) температура, середня температура (Тср.), температурний діапазон (Тдіап. = Tмакс. – Тмін.). Результати. У всіх пацієнтів із політравмою та проведенням ургентних хірургічних втручань відзначається розвиток клінічно значущої ненавмисної гіпотермії. На етапі 60 хвилин інтраопераційного періоду Тсо була вірогідно вище в I групі (35,38 ± 0,28 °С) порівняно з пацієнтами II групи (34,70 ± 0,39 °С) (p &lt; 0,05). Виявлено вірогідно вищий рівень середньої Тсо в I групі (35,53 ± 0,66 °С) порівняно з II групою (34,67 ± 1,74 °С) пацієнтів (p &lt; 0,05). Діапазон температур, який являє собою різницю максимальної та мінімальної Тсо, був вірогідно нижче в I групі пацієнтів (1,36 ± 0,74 °С) порівняно з II групою (4,55 ± 1,11 °С) (p &lt; 0,05). Висновки. Використання в комплексі інтенсивної терапії конвекційної системи зігрівання хоча й не дозволяє досягти вихідних значень Тсо, але попереджає прогресування поглиблення гіпотермії, ефективно забезпечуючи підтримку температурного гомеостазу у критичних пацієнтів із політравмою.

Effects of Co layer thickness and annealing temperature on the magnetic properties of inverted [Pt/Co] multilayers

The effects of Co layer thickness and annealing temperature on the perpendicular magnetic anisotropy (PMA) properties of inverted [Pt (0.2 nm)/Co (tCo)]6 multilayers (where tCo indicates the thickness of the Co layer) have been investigated. The cross-sectional microstructure, as observed from the high-resolution transmission electron microscope images, shows a clear layered structure with atomically flat interfaces both in the as-deposited state as well as after annealing, indicating the interface effects for PMA. The effective PMA energy density (Keff) increases significantly with an increase in tCo from 0.2 to 0.28 nm and then becomes almost saturated with further increases in tCo, followed by a slight reduction at the highest Co thickness, tCo = 0.6 nm. In order to explain the tCo dependence on Keff, the intrinsic PMA energy density (Ki) is calculated by additionally measuring a similar set of results for the saturation magnetization. The Ki value increases nearly linearly with the increase in tCo from 0.2 to 0.5 nm, followed by saturation at a higher tCo value of 0.6 nm. Owing to a close relationship between Ki and the quality of the interfaces, these results indicate a similar tCo dependence on the quality of the interfaces. This is further supported from the magnetic measurements of the samples annealed at the highest temperature of 500 °C, where a second phase is formed, which show a similar tCo dependence on the amount of the second phase. The Ki value is nearly independent of the annealing temperature at tCo ≤ 0.4 nm, above which a substantial reduction is observed, when the annealing temperature exceeds 500 °C.

Magnetic and magnetoresistance studies of the evolution of the magnetic layer structure with Co layer thickness in electrodeposited Co–Cu/Cu multilayers

The structural transformation of electrochemically deposited Co–Cu/Cu multilayers with magnetic layer thickness was monitored via measurements of magnetization and magnetoresistance. For this, electrodeposition of [Co (tCo nm)/Cu (4nm)]50 multilayers were carried out by varying the Co-layer thickness (tCo) down to 0.2nm from a sulfate based single solution electrolyte. Magnetization measurements showed the appearance of anisotropy, increase in remanence magnetization and coercivity with systematic increase of tCo from 0.2 to 1nm. Magnetic field direction dependent magnetoresistance (MR) measurements revealed that the isotropy in MR changes with tCo from tridimensional at 0.2nm to in-plane at 0.4nm to fully anisotropic at 1.0nm. This illustrated that a fully granular magnetic Co-layer structure (tCo=0.2nm) transforms into discontinuous layered one (tCo=0.4nm) due to coalescence of suparparamagnetic regions to a continuous ferromagnetic layer (tCo=1nm).

Effect of coherent to incoherent structural transition on magnetic anisotropy in Co/Pt multilayers

The crystallographic structure and magnetic anisotropy have been investigated in Co/Pt multilayers deposited by direct current magnetron sputtering on two different buffer layers, Ta and Pt. Detail theoretical and experimental investigations reveal the presence of three effects: magneto-elastic, interface and shape anisotropies, and their competition results in three distinct regions based on the Co layer thickness (tCo). In the region I, with tCo&amp;lt; 6 Å, the coherent lattice strain modifies the volume anisotropy through magneto-elastic contribution and it leads to overall positive volume anisotropy energy. With further increase in tCo, lattice mismatch initiates and this results in a decrease in magneto-elastic effect and it enhances the interface anisotropy. The presence of both diminished magneto-elastic effect and enhanced interface anisotropy results in an intermediate region (region II) with negative volume anisotropy energy which is relatively wider (6 Å&amp;lt;tCo&amp;lt; 12 Å) for multilayer stacks with Ta underlayer. In the region III, with tCo&amp;gt; 12 Å, the magneto-elastic effect emerges as an interface phenomena and the shape anisotropy becomes dominant.

Effect of Shear Rate on Crystallisation Phenomena in Olive Oil-Based Organogels

The aim of the present work was the rheological and microstructural analysis of olive oil/mono- and diglycerides/cocoa butter organogels as a potential oil phase of structured food emulsions. Step temperature ramp tests at different shear rates and controlled cooling conditions (5 °C/min) were adopted to evaluate the onset of crystallisation temperature (Tco) and viscosity of different samples. In order to study the crystallisation phenomena potentially occurring in adopted raw materials, a preliminary characterisation was carried out on pure and blended fats (olive oil and/or cocoa butter), evidencing a relevant effect of adopted shear rate on Tco. Afterwards, the influence of mono- and diglycerides on organogelation of either pure or blended fats was investigated, increasing the organogelator from 0.5% (w/w) up to 60% (w/w) and observing the increase of Tco with its concentration from 17.7 ± 2.7 °C up to 64.5 ± 1.0 °C. Experimental results showed that Tco is only determined by the organogelator concentration, and it does not depend on the shear rate and fat source. On the other hand, sample viscosity depends on both the amount of organogelator and the oil phase composition, increasing with saturated fat concentration. Finally, the obtained results allow the fat to be designed with the desired properties: its crystallisation point and rheology can be predicted on the basis of the amounts of the organogelator and the saturated fats, respectively.

Cardiovascular and thermal responses evoked from the periaqueductal grey require neuronal activity in the hypothalamus

Stimulation of neurons in the lateral/dorsolateral periaqueductal grey (l/dlPAG) produces increases in heart rate (HR) and mean arterial pressure (MAP) that are, according to traditional views, mediated through projections to medullary autonomic centres and independent of forebrain mechanisms. Recent studies in rats suggest that neurons in the l/dlPAG are downstream effectors responsible for responses evoked from the dorsomedial hypothalamus (DMH) from which similar cardiovascular changes and increase in core body temperature (T(co)) can be elicited. We hypothesized that, instead, autonomic effects evoked from the l/dlPAG depend on neuronal activity in the DMH. Thus, we examined the effect of microinjection of the neuronal inhibitor muscimol into the DMH on increases in HR, MAP and T(co) produced by microinjection of N-methyl-D-aspartate (NMDA) into the l/dlPAG in conscious rats. Microinjection of muscimol alone modestly decreased baseline HR and MAP but failed to alter T(co). Microinjection of NMDA into the l/dlPAG caused marked increases in all three variables, and these were virtually abolished by prior injection of muscimol into the DMH. Similar microinjection of glutamate receptor antagonists into the DMH also suppressed increases in HR and abolished increases in T(co) evoked from the PAG. In contrast, microinjection of muscimol into the hypothalamic paraventricular nucleus failed to reduce changes evoked from the PAG and actually enhanced the increase in T(co). Thus, our data suggest that increases in HR, MAP and T(co) evoked from the l/dlPAG require neuronal activity in the DMH, challenging traditional views of the place of the PAG in central autonomic neural circuitry.

Structural control of magnetic properties in Co/Pd multilayer for heat assisted perpendicular MRAM application

Temperature dependence of magnetic properties in [Co/Pd]N multilayer have been systematically studied for lithographically patterned samples with different Co thicknesses tCo and the bi-layer number N by extraordinary Hall effect measurements. The perpendicular coercive field Hc decreases with the increase of tCo, excepting a very thin thickness of 1 A. While a threshold temperature (Tth) of Hc vanishing linearly increases with the increase of tCo. The Hc and Tth monotonously increases with the increase of N, ranged from 5 to 50. The superior crystalline structure for samples with the larger N was confirmed from enhanced Co/Pd(111) peak height in the XRD pattern. A practical thermal activation coefficient α of 174 was evaluated from a sweep rate dependence of Hc. A marked improvements for the heat assisted MRAM application was attained by air annealing of [Co(1.7 A)Pd(8 A )]30 at 220 °C, that is, the Hc was increased from 1.3 kOe to 2.9 kOe, while Tth reduced from 210 °C to 190 °C.

Nonmonotonic ferromagnetic thickness dependence of out-of-plane interlayer coupling between two Co∕Pt multilayers across a 11 Å NiO spacer

In [Pt(5Å)∕Co(tCoÅ)]3∕NiO(11Å)∕[Co(tCoÅ)∕Pt(5Å)]3 multilayers, the out-of-plane antiferromagnetic interlayer coupling between the Co∕Pt multilayers can be tailored via varying the Co layer thickness tCo. The coupling strength increases with increase of tCo, but after reaching a maximum at tCo=4.5Å, it decreases with further increase of tCo. At tCo&amp;gt;6Å, no out-of-plane antiferromagnetic interlayer coupling has been observed. This nonmonotonic dependence on tCo of the coupling strength can be attributed to variation of the out-of-plane effective magnetic anisotropy in Co∕Pt multilayers with tCo.

Magnetoresistance of layered structures with alternating in-plane and perpendicular anisotropies

The magnetic properties of (Ni83Fe17/Au/Co/Au) multilayers with different thickness of Au (0.5⩽tAu⩽3nm) and Co (0.2⩽tCo⩽1.5nm) layers were characterized. For tAu⩾1.5nm independent magnetization reversal of Ni–Fe and Co was found. Increase of tCo for (Ni83Fe17-2nm/Au-3nm/Co-tCo/Au-3nm)15 multilayers results in a sequence of transformations in the magnetic properties due to changes in Co microstructure: from superparamagnetic to ferromagnetic clusters at tCo≈0.3nm, from discontinuous to continuous layers at tCo≈0.6nm and from perpendicular to in-plane anisotropy at tCo≈1.2nm.

Effect of Pb addition on thermoelectric power and microhardness of Bi–Pb–Sr–Ca–Cu–O superconductors

The effect of (Pb) addition on the zero thermopower temperature (Tco) and room temperature Vickers microhardness (VHN) of superconducting specimens of different nominal compositions based on the system Bi2−xPbxSr2Ca2Cu3Oy(x=0.0, 0.1, 0.2, 0.3 and 0.5) were studied. The addition of (0.3Pb) resulted in an increase in Tco from 93 to 113K and a 2.85-fold increase in the microhardness for considered loads. This behaviour is ascribed to the presence of large amount of the high-Tc phase (2223). Furthermore, Pb particles may relax the residual stresses resulting from the expansion of individual grains, and may provide increased resistance to crack propagation by pinning the propagating cracks; these effects would increase the hardness. The addition of (0.5Pb) resulted in a decrease in Tco to 98K, and also VHN decreases almost 2.44 times. This decrease in Tco and VHN is believed to be due to the formation of contaminating phases such as Ca2PbO4. Indexed X-ray diffraction patterns indicated that high abundancy of the 2223 phase for the specimen (0.3Pb) are characterized by the sharpest superconducting transitions. Also the present study proved that the most convenient Pb content to obtain a minimum value of porosity is equal (0.3Pb).

Seasonal and interannual variability of oceanic carbon dioxide species at the U.S. JGOFS Bermuda Atlantic Time-series Study (BATS) site

The seasonal and interannual dynamics of the oceanic carbon cycle and the strength of air-sea exchange of carbon dioxide are poorly known in the North Atlantic subtropical gyre. Between October 1988 and December 1993, a time series of oceanic measurements of total carbon dioxide (TCO 2), alkalinity (TA) and calculated pCO 2 was obtained at the Bermuda Atlantic Time-series Study (BATS) site (31°50′N, 64°10′W) in the Sargasso Sea. These measurements constitute the most extensive set of CO 2 species data collected in the oligotrophic North Atlantic. Seasonal changes in surface and water-column CO 2 species were ∼40–50 μmol kg −1 in TCO 2, ∼20 μmol kg −1 in TA, and ∼90–100 μatm in calculated pCO 2. These large changes were driven principally by deep convective winter mixing, temperature forcing and biological activity. TA was well correlated with salinity (with the exception of a 15–25 μmol kg −1 drawdown of TA on one cruise resulting from open-ocean calcification). TCO 2 and pCO 2 were well correlated with seasonal temperature changes (8–9°C). Other underlying processes, such as biological production, advection, gas exchange of CO 2 and vertical entrainment, were important modulators of the carbon cycle, and their importance varied seasonally. Each spring-to-summer, despite the absence of measurable nutrients in the euphotic zone, a 35–40 μmol kg −1 decrease in TCO 2 was attributed primarily to the biological uptake of TCO 2 (evaporation/precipitation balance, gas exchange, and advection were also important). An increase in TCO 2 during the fall months was associated primarily with entrainment of higher TCO 2 subsurface waters. These seasonal patterns require a reassessment of the modelling of the carbon cycle using nutrient tracers and Redfield stoichiometries. Overall, the region is a weak sink (0.22–0.83 mol C m −2 year −1) for atmospheric CO 2. Upper ocean TCO 2 levels increased between 1988 and 1993, at a rate of ∼ 1.7 μmol kg −1 year −1. This increase appears to be in response to the uptake of atmospheric CO 2 through gas exchange or natural variability of the subtropical gyre.

A study of the carbon dioxide system in the northern Indian Ocean during premonsoon

Extensive data sets on the carbon dioxide system in the northern Indian Ocean have been obtained during the premonsoon season. A marked increase (∼ 50 μM) in the total carbon dioxide (TCO 2) content is observed in deep (≥ 1 km) waters of the northern Arabian Sea between approximately 10 and 20°N; contributions from soft tissue decomposition and skeletal solution to the observed increase are about the same. In the Bay of Bengal, the corresponding increase in TCO 2 observed from 11 to 19°N is relatively small (17.5 μM). Significantly, the contribution of the organic decomposition in this region is only 1 7 of the increase in TCO 2. This, together with the earlier reports on large sinking fluxes of particulate organic carbon and pronounced near-bottom anomalies, suggests rapid sinking of organic matter with little decomposition in the water column due to the immense fluvial inputs of lithogenic matter into the Bay of Bengal. The greater extent of organic decomposition in subsurface waters of the Arabian Sea is reflected by generally lower pH and higher pCO 2 levels. This also causes the deep waters in the Arabian Sea to be more corrosive to CaCO 3 than those in the Bay of Bengal. However, the TCO 2 concentrations in the deep Bay of Bengal are slightly higher as compared to those in the Arabian Sea, presumably due to the greater CaCO 3 dissolution in deep waters en route the Bay of Bengal. The atmospheric fluxes of CO 2 are found to be larger in the Arabian Sea (2.9 mmol/m 2/d) than in the Bay of Bengal (0.33 mmol/m 2/d) during the premonsoon season. The overall annual evasion rate of CO 2 from the Arabian Sea and Bay of Bengal has been estimated as ≥ 50 Tg C. These results confirm that the northern Indian Ocean serves as a significant source of atmospheric CO 2.

Response to thermal stress in the rat following acute administration of ethanol.

Several thermoregulatory responses (i.e., colonic temperature, tail-skin temperature, rate of oxygen consumption) were measured in the rat following acute administration of either saline or 3 g ethanol/kg BW i.p. at ambient temperatures (Ta) of 17, 25, and 32 degrees C. The magnitude of the ethanol-induced, hypothermic response was inversely related to Ta, with the decrease in colonic temperature (Tco) at 120 min postinjection ranging from 0.1 degree C at Ta 32 degrees C to 3.2 degrees C at Ta 17 degrees C. Depression of rate of oxygen consumption (heat production) was a major factor contributing to ethanol-induced hypothermia, with no observed differences in heat loss as assessed by differences in the responses of tail skin temperature. Thermoregulatory responses were also measured following acute administration of ethanol at Ta 25 degrees C and immediate exposure to either Ta 32 or 17 degrees C. The increase in Tco of ethanol-treated rats was delayed compared to controls following exposure to 32 degrees C. In addition, tail skin temperature and rate of oxygen consumption of treated rats were significantly lower. The delayed rise in Tco is most likely the result of a reduction in rate of oxygen consumption. When administered ethanol at Ta 25 degrees C and then exposed to Ta 17 degrees C, the rats exhibited a significant recovery from the metabolic depression that characterized the administration of ethanol during exposure to Ta 17 degrees C. This was most likely related to differences in the clearance of ethanol from blood. The results of this study are consistent with the suggestion that the physiologically significant inhibitory effect of acute administration of 3 g ethanol/kg BW on thermoregulatory responses of rats is manifested at the level of heat production rather than heat loss and that the effect is exacerbated by a reduction in Ta.