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The presence of hydrodynamically generated air bubbles has been observed to enhance fine particle flotation in a high intensity agitation (HIA) flotation cell. In this study, the cavitation in an HIA cell, used in our laboratory, is studied by hydrodynamic computational fluid dynamics. Different types of impellers are studied to obtain flow characteristics such as velocity and pressure distributions and turbulent dissipation rate in a two-baffled HIA cell. A cavitation model in conjunction with a multiphase mixture model is used to predict the vapor generation in the HIA cell. Cavitating flow is simulated as a function of revolution speed (RPM) and dissolved gas concentration to understand the dependency of hydrodynamic cavitation on these operating parameters. For comparison, cavitation in a pressure driven flow through a constriction is also modeled. A population balance model is used to obtain bubble size distributions of the generated cavities in a flow through constriction. / Chemical Engineering

Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2007. / Härtill 5 uppsatser.

The purpose of this study was to compare the exercise and recovery muscle oxygenation response of Women and Girls during two 30s Wingate anaerobic tests separated by two minutes of active cycling recovery (resistance ≈ 2.5% body weight, 60-80rpm). Oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (HHb), total hemoglobin (tHb), and tissue saturation index (TSI) were monitored at the right vastus lateralis muscle using near infrared spectroscopy (NIRS) throughout exercise, recovery, and a post-exercise femoral artery occlusion to TSI plateau. Pressure was preset at 250mmHg for Women and 210mmHg for Girls, achieved by rapid inflation in 0.3 seconds, and maintained until a 2 minute TSI plateau occurred or 10 minutes had passed. Twenty Women (23.8[2.12] years) and 13 Girls (9[1] years, combined Tanner stage <4) completed all tasks excepting 1 girl who did not complete occlusion. Significant group, time, and group by time interaction effects were observed for peak and mean power (Watts.kgFFM-1). Women had significantly greater power output compared to Girls for both Wingates. While both groups had reduced power output in Wingate 2, the reduction was significantly greater in Women compared to Girls. No significant group differences were found for resting TSI, recovery TSI, minimum TSI during either Wingate test, or for minimum TSI during occlusion, however a time main effect for Women was observed with minimum TSI being significantly lower in Wingate 1 compared to Wingate 2. Girls had similar minimum TSI for both Wingate tests. Women also demonstrated a significantly greater difference between Wingate minimum TSI and occlusion minimum TSI in Wingate 2 compared to Wingate 1. During Wingate 1, HHb increase was greater in Girls compared to Women and remained elevated during recovery compared to women. Changes in HbO2, HHb, and tHb were reduced in Wingate 2 for both groups, more so in Women for tHb and in Girls for HHb. Recovery was not different between groups with the exception of a faster TSI time constant of recovery in Women (τ =20.25 [13.01]s) compared to Girls (τ =36.77 [13.38]s) which is attributed to a faster HHb time constant in Women (τ =13.6 [0.44]s) compared to Girls (τ =30.77[19.47]s). Both groups demonstrated similar power output results and TSI response across the two Wingate tests but Girls were better able to repeat the anaerobic performance with a consistent TSI minimum between the two tests despite a faster recovery of HHb and TSI in women. These findings, in the context of observed Hb variable differences between groups, provide evidence of greater oxidative metabolism in Girls during a high intensity exercise. / Graduate / December 18, 2016

Real-time acousto-optic (AO) sensing - a dual-wave modality that combines ultrasound with diffuse light to probe the optical properties of turbid media - has been demonstrated to non-invasively detect changes in ex vivo tissue optical properties during high-intensity focused ultrasound (HIFU) exposure. The AO signal indicates the onset of lesion formation and predicts resulting lesion volumes. Although proof-of-concept experiments have been successful, many of the underlying parameters and mechanisms affecting thermally induced optical property changes and the AO detectability of HIFU lesion formation are not well understood. In thesis, a numerical simulation was developed to model the AO sensing process and capture the relevant acoustic, thermal, and optical transport processes. The simulation required data that described how optical properties changed with heating. Experiments were carried out where excised chicken breast was exposed to thermal bath heating and changes in the optical absorption and scattering spectra (500 nm - 1100 nm) were measured using a scanning spectrophotometer and an integrating sphere assembly. Results showed that the standard thermal dose model currently used for guiding HIFU treatments needs to be adjusted to describe thermally induced optical property changes. To model the entire AO process, coupled models were used for ultrasound propagation, tissue heating, and diffusive light transport. The angular spectrum method was used to model the acoustic field from the HIFU source. Spatial-temporal temperature elevations induced by the absorption of ultrasound were modeled using a finite-difference time-domain solution to the Pennes bioheat equation. The thermal dose model was then used to determine optical properties based on the temperature history. The diffuse optical field in the tissue was then calculated using a GPU-accelerated Monte Carlo algorithm, which accounted for light-sound interactions and AO signal detection. The simulation was used to determine the optimal design for an AO guided HIFU system by evaluating the robustness of the systems signal to changes in tissue thickness, lesion optical contrast, and lesion location. It was determined that AO sensing is a clinically viable technique for guiding the ablation of large volumes and that real-time sensing may be feasible in the breast and prostate.

High intensity focused ultrasound (HIFU) provides a wide range of noninvasive therapies ranging from drug delivery to the destruction of kidney stones. In particular, thermal ablation by HIFU presents an effective noninvasive method for the treatment of deep seated solid tumours. HIFU’s further uptake is limited by a need for improved treatment planning and monitoring. Two nonlinear acoustic phenomena that play key roles in HIFU treatment: finite amplitude effects that lead to the generation of harmonics and steepening of wavefronts, and acoustic cavitation. The former must be taken into careful consideration for treatment planning purposes, while the latter has the potential to provide fast, real-time, cost effective treatment monitoring. The first half of this thesis provides new measurements for the nonlinear acoustic properties of tissue, assesses the validity of two common modelling techniques for simulating HIFU fields. The second half develops a new method for combining passive acoustic mapping- an ultrasound monitoring technique- with MR thermometry, to assess estimates of cavitation enhanced heating derived from passive acoustic maps. In the first results chapter B/A was measured in ex-vivo bovine liver, over a heating/ cooling cycle replicating temperatures reached during HIFU ablation, adapting a finite amplitude insertion technique (FAIS), which also allowed for measurement of sound-speed and attenuation. The method measures the nonlinear progression of a plane-wave through liver and B/A was chosen so that numerical simulations matched measured waveforms. Results showed that attenuation initially decreased with heating then increased after denaturation, sound-speed initially increased with temperature and then decreased, and B/A showed an increase with temperature but no significant post-heating change. These data disagree with other reports that show a significant change and suggest that any nonlinear enhancement in the received ultrasound signal post-treatment is likely due to acoustic cavitation rather than changes in tissue nonlinearity. In the second results chapter two common methods of modelling HIFU fields were compared with hydrophone measurements of nonlinear HIFU fields at a range of frequencies and pressures. The two methods usedwere the KZK equation and the commercial package PZFlex. The KZK equation has become the standard method for modelling focused fields, while the validity of PZFlex for modelling these types of transducers is unclear. The results show that the KZK equation is able to match hydrophone measurements, but that PZFlex underestimates the magnitude of the harmonics. Higher order harmonics in PZFlex are not the correct shape, and do not peak around the focus. PZFlex performs worse at higher pressures and frequencies, and should be used with caution. In the final two chapters a system for estimating cavitation-enhanced heating from acoustic maps is developed and benchmarked against magnetic resonance thermometry methods. The first chapter shows that the ultrasound and MR monitoring systems are compatible, and registers the two imaging systems. The HIFUfocus is clearly visible in passive maps acquired in the absence of cavitation and these coincide with the centre of heating in MR temperature images. When cavitation occurs, it coincides spatially and temporally with the appearance of a clear spike in temperature, especially when the passive maps are processed using the Robust Capon Beamformer algorithm. The final chapter shows how passive maps can be converted into thermal heating inputs, and used to estimate cavitation-enhanced temperature increases. These estimates have the potential to closely match maximum temperature rise, and estimated thermal dose after the estimated temperature rise is spatially averaged. However, themethod is not always successful. This is partly due to uncertainties in MR thermometry estimates, partly due to uncertainties in the acoustic properties of tissue.

Milk is one of the eight major food allergens. Cow's milk allergy is the most common allergy in children under 2 years of age. About 1.6 to 2.8 percent of children under this age are reported to have cow's milk allergy. Casein, β-lactoglobulin and α-lactalbumin are major milk protein allergens. Nonthermal treatments like high intensity ultrasound, ultraviolet (UV) light and nonthermal plasma treatments have been reported in the literature to be effective in reducing the allergenicity of different food proteins. Hence it was expected for these treatments to reduce cow milk allergenicity. The objective of this study was to investigate the effect of high intensity ultrasound, nonthermal atmospheric plasma and UV-C light treatments in reducing the allergenicity of isolated major milk proteins. Sonics Vibracell VC 505 ultrasonic liquid processor was used to perform high intensity ultrasound treatments. UV light treatments were performed using a DDK Scientific Corporation UV tunnel. A nonthermal atmospheric plasma setup assembled in Department of Microbiology lab was used to perform plasma treatments. Samples were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to estimate the change in protein concentration and enzyme linked immuno sorbent assays (ELISA) to observe the change in IgE binding. A one-way analysis of variance was conducted to evaluate the relationship between treatment time and percent IgE binding at 95% confidence level. Further investigation was conducted with nuclear magnetic resonance (NMR) spectroscopy on treated casein to assess any change in the structure of protein. SDS-PAGE results for ultrasound and plasma treatments didn't show any change in gel band intensities for casein, β-lactoglobulin and α-lactalbumin indicating no significant change in protein concentration. Ci-ELISA analysis showed that there was no significant difference (p>0.05) in IgE binding values for control and treated samples in ultrasound and plasma treatment conditions tested in this study. The intensities of all the three protein bands in SDS-PAGE gel were reduced by UV-C light treatment at 15 min treatment time. In Ci-ELISA, there was a significant difference (p< 0.05) in IgE binding values for control and treated samples and a reduction in allergenicity of proteins (25% reduction for casein and 28% reduction for whey protein fractions) was observed. Further investigations using in vivo clinical trials need to be conducted to confirm this result. NMR results didn't show any noticeable changes in the structures of casein with all three different treatments. In conclusion, UV-C light treatment can reduce the allergenicity of isolated major milk proteins to some extent. High intensity ultrasound and nonthermal atmospheric plasma treatments failed to generate effective results for reducing allergenicity at the conditions tested in this study. Higher intensity and longer treatment conditions might yield better results with ultrasound treatment. Different power and gas flow rates used to generate plasma with direct exposure of proteins might yield better results towards reducing the allergenicity of major milk allergens.

abstract: Obesity prevalence is high in the United States, in part due to increased fat storage following consumption of high fat/carbohydrate (sugar) foods. Following a meal, carbohydrate stimulates its own oxidation, while simultaneously suppressing fat oxidation, ultimately leading to fat storage. Aerobic exercise preceding a meal increases fat oxidation in the postprandial period, which may reduce fat storage. The ideal exercise prescription for optimal postprandial fat oxidation is unknown. The effect of low and moderate intensity continuous exercise (MIE) has been studied extensively, while the effects of high-intensity interval exercise (HIIE) on post-prandial substrate oxidation has not been examined. The purpose of this study was to compare the effects of MIE and HIIE on postprandial substrate oxidation after consumption of an isocaloric meal (2 glazed donuts; 520 kcal) in healthy adults. Ten subjects (8 males, 2 females; age=24yr, BMI=24 kg/m2) completed three conditions in random order: 1) no exercise control; 2) MIE: cycling at 60-75%HRmax; 3) HIIE: cycling at 90-95%HRmax. The duration of each exercise bout was sufficient to expend approximately 520 kcal, the energy equivalent of the donuts, which were consumed 1 hour post-exercise. Immediately after consuming the donuts, pulmonary ventilation and gas exchange were measured breath-by-breath continuously and recorded (min-by-min) for 5 hours. Repeated measures analysis of covariance was used to compare the mean differences in outcome variables accounting for gender. Absolute postprandial fat oxidation (g/5 hours) was 17.3±5.4, 27.1±9.6 and 23±1.2 for control, MIE and HIIE trials respectively, with the postprandial fat oxidation significantly greater for the two exercise conditions compared to control. Relative to baseline values, both exercise conditions resulted in cumulative net postprandial fat oxidation significantly greater than control (control = -1.79±3.99g; MIE = 11.51±8.41g, HIIE= 9.51±5.20g). Therefore, results indicate that exercise most certainly increases postprandial fat oxidation, and that exercise type, either MIE or HIIE, is not as important as total energy expended. The fact that exercise of ~1 hour was required to oxidize the amount of fat in two donuts, that required only a few minutes to consume, highlights the challenges of using exercise for weight control in an obesogenic environment. / Dissertation/Thesis / Masters Thesis Nutrition 2018

A síndrome metabólica (SM) é uma somatória de fatores de risco para desenvolvimento de doenças cardiovasculares (DCV), intimamente ligada à obesidade e, assim como a última, sua prevalência cresce mundialmente. Sua etiologia é complexa e suas causas são influenciadas por fatores ambientais e genéticos. Sabe-se que a elevação da capacidade cardiorrespiratória (VO2máx) seja um melhor atenuador do risco de mortalidade por DCV do que a própria obesidade. Atualmente a forma conhecida para aumento do VO2máx é o exercício físico aeróbio, porém vários indivíduos reportam falta de tempo para realização de uma rotina de exercícios físicos. Neste contexto, o presente trabalho teve como objetivo comparar dois protocolos de treinamento aeróbio de alta intensidade e outro contínuo de moderada intensidade quanto à influência na capacidade cardiorrespiratória, variáveis de síndrome metabólica (circunferência da cintura - CC, glicemia de jejum, HDL, triglicérides e pressão arterial) e composição corporal (massa e percentual de gordura) em indivíduos com sobrepeso/obesidade e; observar a influência de polimorfismos dos genes visfatina e receptor tipo 1 de angiotensina 2 (AGTR1) nos níveis de glicemia, HDL, triglicérides e pressão arterial. 40 indivíduos foram divididos aleatoriamente em três grupos de treinamento: contínuo moderado (CM), 4x1 e 4x4. O grupo CM realizou cinco sessões semanais de treino por 30 minutos; os grupos 4x1 e 4x4 realizaram 3 sessões semanais com duração de 19 e 40 minutos, respectivamente. A intervenção durou 16 semanas e as sessões foram monitoradas quanto à frequência cardíaca para controlar a intensidade do exercício. O grupo CM se exercitou a 70% da frequência cardíaca máxima, enquanto os grupos 4x1 e 4x4 realizaram estímulos a 90% da frequência cardíaca máxima. Os resultados encontrados apontaram uma melhora na capacidade cardiorrespiratória em todos os grupos, sem diferença entre eles. Diminuição da massa corpórea, IMC, percentual de gordura somente no grupo 4x4. Diminuição de CC nos grupos 4x4 e CM. Os dados da análise genética não apontaram nenhuma relação entre os polimorfismos avaliados e as variáveis de interesse. Por fim, concluiu-se que o treinamento de alta intensidade com duração de 19 minutos promove resultados semelhantes ao treinamento de mesma intensidade e duração de 40 minutos e ao treinamento de intensidade moderada na capacidade cardiorrespiratória em indivíduos com sobrepeso/obesidade, sendo uma alternativa viável para treinamento físico com pouco volume. / Metabolic syndrome (MS) is a sum of risk factors for developing cardiovascular disease (CVD), closely linked to obesity and, like the latter, its prevalence is growing worldwide. Its etiology is complex and its causes are influenced by environmental and genetic factors. It is known that the increase in cardiorespiratory fitness (VO2max) is a better attenuator of CVD mortality risk rather than obesity itself. Currently, the best known way to increase VO2max is aerobic exercise, but many people report lack of time to perform a exercise routine exercise. In this context, this study aimed to compare two high intensity aerobic exercise protocols and a continuous moderate exercise regarding their effects on cardiorespiratory fitness, metabolic syndrome variables (waist circumference - WC, fasting plasma glucose, HDL, triglycerides, and blood pressure) and body composition (body mass and fat percentage) in overweight/obese individuals and; observe the influence of genetic polymorphisms of visfatin and angiotensin 2 receptor type 1(AGTR1) in blood glucose levels, HDL, triglycerides and blood pressure. 40 subjects were randomly divided into three training groups: continuous moderate intensity (CM), 4x1 and 4x4. The CM group held five weekly training sessions for 30 minutes; the 4x1 and 4x4 groups performed three weekly sessions lasting 19 and 40 minutes, respectively. The intervention lasted 16 weeks and the sessions were monitored for heart rate to control the exercise intensity. The CM group exercised at 70% of maximum heart rate, while the 4x1 and 4x4 groups performed stimuli to 90% of maximum heart rate. The findings showed an improvement in cardiorespiratory fitness in all groups, with no difference between them. A decreased body mass, BMI, body fat percentage only in the group 4x4. WC decrease in 4x4 and CM groups. Data from genetic analysis did not show any relationship between the evaluated polymorphisms and the variables of interest. Finally, it was concluded that the high intensity training lasting 19 minutes promotes similar results to the training of the same intensity and duration of 40 minutes and moderate intensity training on cardiorespiratory fitness in overweight/obese individuals, being a viable alternative for exercise training with low volume.

Made available in DSpace on 2014-06-11T19:22:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-05Bitstream added on 2014-06-13T19:49:05Z : No. of bitstreams: 1 dalia_ra_me_rcla.pdf: 910850 bytes, checksum: eac946a1f4330146a0755088ee83927b (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Apesar dos avanços nas pesquisas na área de atividade física e medicina, ainda existem diversas contradições a respeito do real risco e benefício da utilização do exercício físico resistido, principalmente o de força de alta intensidade, para hipertensos no que tange suas variáveis metabólicas. Desta forma, o objetivo desta dissertação foi analisar a influência de um programa de treinamento físico de alta intensidade sobre o metabolismo glicídico, protéico, lipídico e hormonal de ratos espontaneamente hipertensos. Para isso utilizamos ratos machos da linhagem de animais espontaneamente hipertensos (SHR) e ratos Wistar Kyoto (WKY), com 20 semanas de vida. Os animais foram divididos em quatro grupos: SHR Sedentário (SHRS); SHR Treinado (SHRT); WKY Sedentário (WKYS); WKY Treinado (WKYT). O treinamento físico de alta intensidade constituía de natação em tanques individuais, na qual os animais realizavam saltos através de uma mochila com velcro acoplada ao tórax do animal, na qual continha uma resistência equivalente a 50% da massa corporal do mesmo, na forma de chumbinhos. Eram realizadas quatro séries de 10 saltos, tendo um intervalo de 1 minuto entre cada série, em cinco dias na semana, durante um período de oito semanas consecutivas. Após o final do treinamento físico os animais passaram pelos testes de tolerância oral a glicose e tolerância a insulina, e após este período os animais forma eutanasiados e coletado soro, através do sangue coletado diretamente do coração, apara as dosagens de glicose, triglicerídeos, colesterol total, HLD e LDL colesterol, proteínas totais, albumina e creatina quinase (CK) e CK-MB, insulina e IGF-1, GH e ácidos graxos livres (A.G.L). Amostras do músculo gastrocnêmio, porções brancas e vermelhas, sóleo, fígado e coração foram coletados e utilizados para avaliação do conteúdo de glicogênio, proteína e DNA... / In spite of progress in researches in exercise and medicine area, still several contradictions exist regarding the real risk and benefit of use resistance exercise, mainly the high-intensity, for hypertension in what plays their metabolic variables. This way, objective of this dissertation was to analyze the influence of a high-intensity training program on the glucose, protein, lipids and hormonal metabolism of spontaneously hypertensive rats. For that we used male of lineage of spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY), with 20 weeks of life. The animals were divided in four groups: Sedentary SHR (SHRS); Trained SHR (SHRT); Sedentary WKY (WKYS); Trained WKY (WKYT). The high intensity training constituted of jumps in the water, in individual tanks, wearing a jacket coupled to the thorax containing a lead overload equivalent to 50% of the body mass. Four series of 10 jumps were accomplished, with an interval of 1 minute among each series, five days a week, during eight consecutive weeks. After the end of exercise training the animals went by the glucose tolerance tests and insulin tolerance test, and after this period all animals were killed and serum collected, through the blood collected directly of heart, it trims the glucose, triglycerides, total cholesterol, HLD and LDL cholesterol, total proteins, albumin and creatine kinase (CK) and CK-MB, insulin and IGF-1, GH and free fat acids (FFA). Samples of muscle gastrocnemius, white and red portions, soleus, liver and heart were collected and used for glycogen content, protein and DNA. In the hepatic and heart samples were still collected for analysis of IGF-1 and triglycerides. The supra-renal glands were removed for evaluation levels of total cholesterol through method enzymatic colorimeter. In the soleus muscle they were removed sliced for analyses synthesis and degradation for muscle... (Complete abstract click electronic access below)