Track of HSMS Sophia tracing the extent of navigable water along the main northern ice between Spitzbergen and Greenland September 1868 : also showing the nature of the ice and temperature and depth of the sea

Kartta kuuluu A. E. Nordenskiöldin kokoelmaan

Temperature, air pollution, and mortality from myocardial infarction in São Paulo, Brazil

An increase in daily mortality from myocardial infarction has been observed in association with meteorological factors and air pollution in several cities in the world, mainly in the northern hemisphere. The objective of the present study was to analyze the independent effects of environmental variables on daily counts of death from myocardial infarction in a subtropical region in South America. We used the robust Poisson regression to investigate associations between weather (temperature, humidity and barometric pressure), air pollution (sulfur dioxide, carbon monoxide, and inhalable particulate), and the daily death counts attributed to myocardial infarction in the city of São Paulo in Brazil, where 12,007 fatal events were observed from 1996 to 1998. The model was adjusted in a linear fashion for relative humidity and day-of-week, while nonparametric smoothing factors were used for seasonal trend and temperature. We found a significant association of daily temperature with deaths due to myocardial infarction (P < 0.001), with the lowest mortality being observed at temperatures between 21.6 and 22.6ºC. Relative humidity appeared to exert a protective effect. Sulfur dioxide concentrations correlated linearly with myocardial infarction deaths, increasing the number of fatal events by 3.4% (relative risk of 1.03; 95% confidence interval = 1.02-1.05) for each 10 µg/m³ increase. In conclusion, this study provides evidence of important associations between daily temperature and air pollution and mortality from myocardial infarction in a subtropical region, even after a comprehensive control for confounding factors.

Pressure-induced dissociation of casein micelles: size distribution and effect of temperature

Pressure-induced dissociation of a turbid solution of casein micelles was studied in situ in static and dynamic light scattering experiments. We show that at high pressure casein micelles decompose into small fragments comparable in size to casein monomers. At intermediate pressure we observe particles measuring 15 to 20 nm in diameter. The stability against pressure dissociation increased with temperature, suggesting enhanced hydrophobic contacts. The pressure transition curves are biphasic, compatible with a temperature (but not pressure)-dependent conformational equilibrium of two micelle species. Our thermodynamic model predicts an increase in structural entropy with temperature.

Differences in pressure and temperature transitions of proteins and polymer gels

Pressure-driven and temperature-driven transitions of two thermoresponsive polymers, poly(N-isopropylacrylamide) (pNIPAM) and poly(N-vinylisobutyramide) (pNVIBA)), in both a soluble linear polymer form and a cross-linked hydro-gel form, were examined by a dynamic light-scattering method and direct microscopic observation, respectively. Their behavior was compared with that of protein systems. Changes in some characteristic parameters in the time-intensity correlation functions of dynamic light-scattering measurement of aqueous solutions of pNIPAM at various pressures and temperatures showed no essential differences during temperature and pressure scanning and, as a whole, the motions of polymers in aqueous solutions were similar in two types of transitions until chain shrinkage occurred. The gels (cross-linked polymer gels) prepared from the thermoresponsive polymers also showed similar volume transitions responding to the pressure and temperature increase. In temperature transitions, however, gels showed drastic volume shrinkage with loss of transparency, while pressure-induced transition showed a slow recovery of transparency while keeping the size, after first transient drastic volume shrinkage with loss of transparency. At a temperature slightly higher than the transition under atmospheric temperature, so-called reentry of the volume change and recovery of the transparency were observed during the pressure-increasing process, which implies much smaller aggregation or non-aggregated collapsed polymer chains in the gel at higher pressures, indicating a certain mechanistic difference of the dehydration processes induced by temperature and pressure.

Bumblebees in a Changing Climate: Evaluating the Effects of Temperature on Queen Performance

Bumblebees are a very essential group of pollinating insects, but their populations have declined drastically during the past decades. We need to understand why their numbers are decreasing and what can be done to reverse this trend. Climate change-related phenomena, such as changes in the overwintering temperatures and spring conditions, are among the most prominent threats to bumblebees. Queens have a special role in the lifecycle of bumblebees because they overwinter and start new colonies the next year. Their successful performance: survival, overwintering ability, longevity, immune competence, and nest establishing capability in spring, is highly important for bumblebee populations. However, the effects of climate change on bumblebee queen performance remain unknown. The main objective of this thesis was to assess how temperature affects the performance of bumblebee queens during and after overwintering. The effects of warm temperature predicted by climate change scenarios on queen survival and stress-tolerance were studied by a four-month artificial diapause of bumblebee queens at two temperatures (9°C and 1.8°C). Bumblebee colonies were also reared in a laboratory and factors affecting colony characteristics were examined. In addition, queen performance during spring was studied in a starvation experiment using two temperatures (15°C as normal; 24°C as warmer than average) and queens collected from nature right after their emergence. My research revealed how temperature affects queen performance, and queen size was found to be an important factor determining the direction of some of these effects. We found a 0.4g weight threshold for bumblebee queens to be able to survive overwintering. In addition, during mild winters, larger queens have a higher chance than smaller ones to survive through winter and also to cope with immunological stresses after overwintering. During cold conditions, which are normal in the current climatic situation, this advantage disappears. In the spring starvation experiment, the starved queens survived approximately eight days longer in 15°C than in 24°C, which means that starvation risk rises significantly with increasing spring temperature, in a situation where food is scarce due to for example frost damage or asynchrony between bumblebees and their important food plants. These results could mean that in the future climate, larger queens are better able to survive the winter, initiate their nests and start rearing their offspring. This may be problematic, because I also detected two alternative strategies of colony development that differ between large and small queens; larger queens start to lay eggs earlier at nest initiation, their colonies mature later, they produce more workers, and they have a more strongly male biased sex allocation compared with smaller queens. If larger queens have a greater change of producing offspring after a mild winter, this could lead to a significant decline in the total production of new queens at a population level. Thus, it seems that queen size could act as one mechanism regulating the population level outcomes in different temperatures. The new information presented in my thesis reinforces that basic research, monitoring, and local species conservation of bumblebees both in Finland and globally must be increased to ensure that this highly important pollinator group survives in the face of climate change.

A cost-effective melting temperature assay for the detection of single-nucleotide polymorphism in the MBL2 gene of HIV-1-infected children

We report a fast (less than 3 h) and cost-effective melting temperature assay method for the detection of single-nucleotide polymorphisms in the MBL2 gene. The protocol, which is based on the Corbett Rotor Gene real time PCR platform and SYBR Green I chemistry, yielded, in the cohorts studied, sensitive (100%) and specific (100%) PCR amplification without the use of costly fluorophore-labeled probes or post-PCR manipulation. At the end of the PCR, the dissociation protocol included a slow heating from 60º to 95ºC in 0.2ºC steps, with an 8-s interval between steps. Melting curve profiles were obtained using the dissociation software of the Rotor Gene-3000 apparatus. Samples were analyzed in duplicate and in different PCR runs to test the reproducibility of this technique. No supplementary data handling is required to determine the MBL2 genotype. MBL2 genotyping performed on a cohort of 164 HIV-1-positive Brazilian children and 150 healthy controls, matched for age and sex and ethnic origin, yielded reproducible results confirmed by direct sequencing of the amplicon performed in blind. The three MBL2 variants (Arg52Cys, Gly54Asp, Gly57Glu) were grouped together and called allele 0, while the combination of three wild-type alleles was called allele A. The frequency of the A/A homozygotes was significantly higher among healthy controls (0.68) than in HIV-infected children (0.55; P = 0.0234) and the frequency of MBL2 0/0 homozygotes was higher among HIV-1-infected children than healthy controls (P = 0.0296). The 0 allele was significantly more frequent among the 164 HIV-1-infected children (0.29) than among the 150 healthy controls (0.18; P = 0.0032). Our data confirm the association between the presence of the mutated MBL2 allele (allele 0) and HIV-1 infection in perinatally exposed children. Our results are in agreement with the literature data which indicate that the presence of the allele 0 confers a relative risk of 1.37 for HIV-1 infection through vertical transmission.

Spin-electromagnetic waves spectra in multiferroic heterostructures

This work devotes to the theoretical investigations of spin-electromagnetic waves (SEW) propagating in a thin-film multiferroic structures that were composed of a slot-line and structures with several ferrite films. In contrast to earlier works, the spin-electromagnetic waves in the investigated structures are originated from two different electrodynamics coupling. The first one is coupling of the electromagnetic wave localized mainly in the slot-line with the spin wave excited mostly in the ferrite film. The second one is coupling of two spin waves in the different ferrite films separated by a thin ferroelectric film. For theoretical analysis of SEWs propagation in such kind of structures theories of their eigen-wave spectra were developed. Spectra of SEW in the investigated structures were calculated and analyzed. The range of electric and magnetic tunability of dispersion characteristic were investigated. Spectra of SEW in the investigated multiferroic structures are used for investigation of transfer function of periodic structures.

Magnetic properties of defective graphene

In this thesis, the influence of the functionalization of graphene and graphite on their magnetic properties was investigated. The functionalization was performed by covalent attaching of a phenyl groups with three different radicals (4-bromoaniline, 4-chloroaniline and 4-nitroaniline). Magnetic properties were measured by SQUID magnetometer. Both pristine graphite and graphene showed strong diamagnetic behavior. For good quality graphite, diamagnetism was found to be temperature-dependent. All samples demonstrated noticeable paramagnetic contribution below 50 K. According to fitting experimental results with Brillouin function and Curie law, it was shown that paramagnetism is provided by small clusters of spins (superparamagnetic behavior). Moreover, the clusters size and spin concentrations were calculated. For the samples functionalized with nitroaniline the antiferromagnetic transition around 120 K was observed. To explain this behavior, a simple model was proposed. Additional analysis of the graphene quality, structure and composition of the samples was carried out by HRTEM, EDS mapping, Raman spectroscopy and X-ray diffraction techniques.

The effect of epidural and general anesthesia on newborn rectal temperature at elective cesarean section

Both epidural and general anesthesia can impair thermoregulatory mechanisms during surgery. However, there is lack of information about the effects of different methods of anesthesia on newborn temperature. The purpose of this study was to determine whether there are differences in newborn rectal temperature related to type of anesthesia. Sixty-three pregnant women were randomly assigned to receive general or epidural anesthesia. Maternal core temperature was measured three times with a rectal probe just before anesthesia, at the beginning of surgery and at delivery. In addition, umbilical vein blood was sampled for pH. The rectal temperatures of the babies were recorded immediately after delivery, and Apgar scores were determined 1, 5, and 10 min after birth. The duration of anesthesia and the volume of intravenous fluid given during the procedure (833 ± 144 vs 420 ± 215 mL) were significantly higher in the epidural group than in the general anesthesia group (P < 0.0001). Maternal rectal temperatures were not different in both groups at all measurements. In contrast, newborn rectal temperatures were lower in the epidural anesthesia group than in the general anesthesia group (37.4 ± 0.3 vs 37.6 ± 0.3°C; P < 0.05) immediately after birth. Furthermore, the umbilical vein pH value (7.31 ± 0.05 vs 7.33 ± 0.01; P < 0.05) and Apgar scores at the 1st-min measurement (8.0 ± 0.9 vs 8.5 ± 0.7; P < 0.05) were lower in the epidural anesthesia group than in the general anesthesia group. Since epidural anesthesia requires more iv fluid infusion and a longer time for cesarean section, it involves a risk of a mild temperature reduction for the baby which, however, did not reach the limits of hypothermia.

Association between the increase in brain temperature and physical performance at different exercise intensities and protocols in a temperate environment

There is evidence that brain temperature (Tbrain) provides a more sensitive index than other core body temperatures in determining physical performance. However, no study has addressed whether the association between performance and increases in Tbrain in a temperate environment is dependent upon exercise intensity, and this was the primary aim of the present study. Adult male Wistar rats were subjected to constant exercise at three different speeds (18, 21, and 24 m/min) until the onset of volitional fatigue. Tbrain was continuously measured by a thermistor inserted through a brain guide cannula. Exercise induced a speed-dependent increase in Tbrain, with the fastest speed associated with a higher rate of Tbrain increase. Rats subjected to constant exercise had similar Tbrain values at the time of fatigue, although a pronounced individual variability was observed (38.7-41.7°C). There were negative correlations between the rate of Tbrain increase and performance for all speeds that were studied. These results indicate that performance during constant exercise is negatively associated with the increase in Tbrain, particularly with its rate of increase. We then investigated how an incremental-speed protocol affected the association between the increase in Tbrain and performance. At volitional fatigue, Tbrain was lower during incremental exercise compared with the Tbrain resulting from constant exercise (39.3±0.3 vs 40.3±0.1°C; P<0.05), and no association between the rate of Tbrain increase and performance was observed. These findings suggest that the influence of Tbrain on performance under temperate conditions is dependent on exercise protocol.

Accuracy of dose planning for prostate radiotherapy in the presence of metallic implants evaluated by electron spin resonance dosimetry

Radiotherapy is one of the main approaches to cure prostate cancer, and its success depends on the accuracy of dose planning. A complicating factor is the presence of a metallic prosthesis in the femur and pelvis, which is becoming more common in elderly populations. The goal of this work was to perform dose measurements to check the accuracy of radiotherapy treatment planning under these complicated conditions. To accomplish this, a scale phantom of an adult pelvic region was used with alanine dosimeters inserted in the prostate region. This phantom was irradiated according to the planned treatment under the following three conditions: with two metallic prostheses in the region of the femur head, with only one prosthesis, and without any prostheses. The combined relative standard uncertainty of dose measurement by electron spin resonance (ESR)/alanine was 5.05%, whereas the combined relative standard uncertainty of the applied dose was 3.35%, resulting in a combined relative standard uncertainty of the whole process of 6.06%. The ESR dosimetry indicated that there was no difference (P>0.05, ANOVA) in dosage between the planned dose and treatments. The results are in the range of the planned dose, within the combined relative uncertainty, demonstrating that the treatment-planning system compensates for the effects caused by the presence of femur and hip metal prostheses.

Theoretical modelling of Staphylococcus aureus growth in a cooked meat product kept at ambient temperature using temperature profiles of selected Mexican cities

A theoretical model is used to predict the growth of Staphylococcus aureus in a pasteurized meat product kept at ambient temperatures for several hours. For this purpose, the temperature profiles of some cities of Mexico were combined with literature data on the kinetics of S. aureus growth. As shown by theoretical predictions, if the food is kept at ambient temperature, the average daily temperature may not give accurate predictions.

Influence of temperature on the respiration rate of minimally processed organic carrots (Daucus Carota L. cv. Brasília)

The objective of this work was to study the influence of temperature on the respiration rate of minimally processed organic carrots (Daucus Carota L. cv. Brasília) with and without the application of a gelatin film. The samples were packed in flexible bags and stored at 1, 5 and 10 °C. During the five days of storage, the CO2 and O2 concentrations in the headspace of the package were monitored by gas chromatography, and the mathematical model based on enzymatic kinetics was used to estimate the respiration rate of minimally processed organic carrots. The effect of temperature on the respiration rate was evaluated by the Arrhenius equation. The results showed that the O2 concentration decreased during the storage period and the CO2 concentration increased. The lowest O2 concentrations of 2.59 and 2.66% were found for the samples stored at 10 °C with and without the film, respectively. For the CO2 concentration, the highest concentrations of 16.25 and 16.32% were again found for the temperature of 10 °C with and without the application of the film, respectively. At the temperature of 1 °C, the maximum respiratory rates for the samples without and with the film were 10.82 and 10.44 mL CO2.kg-1/hour, respectively, after 72 hours of storage. The greatest respiratory rate was obtained at 10 °C, the maximum peak being reached after 50 hours. Activation energy values were of 50.59 kJ.mol-1, for the samples with the film, and 51.88 kJ.mol-1 for the samples without the film.

Effect of air-temperature and diet composition on the drying process of pellets for japanese abalone (Haliotis discus hannai) feeding

The aim of this research was to study the effect of air-temperature and diet composition on the mass transfer kinetics during the drying process of pellets used for Japanese Abalone (Haliotis discus hannai) feeding. In the experimental design, three temperatures were used for convective drying, as well as three different diet compositions (Diets A, B and C), in which the amount of fishmeal, spirulin, algae, fish oil and cornstarch varied. The water diffusion coefficient of the pellets was determined using the equation of Fick's second law, which resulted in values between 0.84-1.94×10-10 m²/s. The drying kinetics was modeled using Page, Modified Page, Root of time, Exponential, Logarithmic, Two-Terms, Modified Henderson-Pabis and Weibull models. In addition, two new models, referred to as 'Proposed' models 1 and 2, were used to simulate this process. According to the statistical tests applied, the models that best fitted the experimental data were Modified Henderson-Pabis, Weibull and Proposed model 2, respectively. Bifactorial analysis of variance ANOVA showed that Diet A (fishmeal 44%, spirulin 9%, fish oil 1% and cornstarch 36%) presented the highest diffusion coefficient values, which were favored by the temperature increase in the drying process.

Effects of heat treatment and storage temperature on the use of açaí drink by nutraceutical and beverage industries

This study assesses the storage temperature effect on the anthocyanins of pasteurized and unpasteurized açaí pulp. The data was obtained using a pasteurized and lyophilized pulp (PLP) to evaluate the temperature effect (0, 25, and 40 °C). Part of non-pasteurized frozen pulp (NPP) was pasteurized (NPP-P) at 90 °C for 30 seconds; both pulps were stored at 40 °C. The anthocyanin content reduction in the drink was evaluated from the half-life time (t1/2), activation energy (Ea), temperature quotient (Q10), and the reaction rate constant (k). The t1/2 of the PLP anthocyanins stored at 40 °C was 1.8 times less than that stored at 25 °C and 15 times less than that stored at 0 °C; therefore, the higher temperatures decreased the stability of anthocyanins. The pasteurization increased the t1/2 by 6.6 times (10.14 hours for NPP and 67.28 hours for NPP-P). The anthocyanin degradation on NPP-P followed a first order kinetic, while NPP followed a second order kinetic; thus it can be said that the pasteurization process can improve the preservation of anthocyanins in the pulp.