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Focused ultrasound combined with intravenously injected microbubbles is a promising non-invasive therapy capable of temporarily disrupting the blood-brain barrier for targeted drug delivery. Established in vivo experiments on rodent models combine focused ultrasound treatment with two-photon microscopy imaging to improve understanding of microvasculature response. A phased array, an advanced ultrasound therapy device, was successfully developed to improve pressure transmission in these experiments. An investigation of transducer sensitivity to setup equipment suggested modifications to setup procedures, for example recording objective position, may improve in situ pressure estimates. A ring array composed of 50 lateral mode elements, geometry determined by pressure field simulations, was successfully fabricated. Fibre optic hydrophone pressure field measurements confirmed the device had an appropriate focal size (0.7mm diameter x 4mm axial length) and reached therapeutic pressure levels (>0.5MPa). Ex vivo transcranial measurements demonstrated moderate focal correction and off-axis steering capabilities that may improve experimental throughput and target alignment.

Focused ultrasound combined with intravenously injected microbubbles is a promising non-invasive therapy capable of temporarily disrupting the blood-brain barrier for targeted drug delivery. Established in vivo experiments on rodent models combine focused ultrasound treatment with two-photon microscopy imaging to improve understanding of microvasculature response. A phased array, an advanced ultrasound therapy device, was successfully developed to improve pressure transmission in these experiments. An investigation of transducer sensitivity to setup equipment suggested modifications to setup procedures, for example recording objective position, may improve in situ pressure estimates. A ring array composed of 50 lateral mode elements, geometry determined by pressure field simulations, was successfully fabricated. Fibre optic hydrophone pressure field measurements confirmed the device had an appropriate focal size (0.7mm diameter x 4mm axial length) and reached therapeutic pressure levels (>0.5MPa). Ex vivo transcranial measurements demonstrated moderate focal correction and off-axis steering capabilities that may improve experimental throughput and target alignment.

In pregnancy, the maternal cardiovascular and placental circulation undergoes structural and functional changes to accommodate the growing fetus, but the mechanisms involved are not fully understood. Nitric oxide (NO) increases in normal pregnancy and lack of NO has been implicated in pregnancy related complications, preeclampsia and fetal growth restriction. Thus, the objective of the thesis was to determine if cardiovascular, uteroplacental and fetoplacental changes observed in human pregnancy also occur in mice and to assess the obligatory role of eNOS in mediating these changes. I showed that like humans, mice exhibit increases in maternal cardiac output, stroke volume, plasma volume, and uterine arterial blood flow, and a transient decrease in arterial pressure during pregnancy. Importantly, I showed that endothelial nitric oxide synthase (eNOS) plays an important role in promoting the progressive increase in maternal cardiac chamber dimensions and output and the enlargement of the aorta during pregnancy in mice. Another novel finding was that eNOS plays an important role in remodeling of the uterine and umbilical vasculatures during pregnancy. The remodeling of the uterine vasculatures, including the uterine and spiral arteries, were blunted in the eNOS KO mice with ko fetuses (KO(ko)) and this likely contributed to elevated vascular resistance and reduced perfusion of the uterine circulation during pregnancy. Impaired spiral artery remodeling may be caused by a deficiency in decidual uterine natural killer cells. Fetal placental vascularization was also impaired in eNOS KO(ko) mice, which likely increased vascular resistance and thereby reduced fetoplacental perfusion. Reduced vascularization may be due to decreased VEGF mRNA and protein expression in KO(ko) placentas. Decreased perfusion in both the uterine and umbilical circulations most likely contributed to elevated placental and fetal hypoxia in the eNOS KO(ko) mice. Interestingly, despite placental hypoxia, eNOS KO(ko) mice do not show the classical signs of preeclampsia including hypertension and proteinuria nor are maternal plasma sFlt1 levels elevated. Nevertheless, eNOS KO(ko) pups are growth restricted at term, and this is mainly due to the fetal genotype. These findings suggest that eNOS plays an essential role during pregnancy in remodeling of the maternal heart, aorta, and uterine and umbilical vasculatures thereby augmenting blood flow to the maternal and fetal sides of the placenta and thereby promoting fetal growth in mice.

Parengtas bakalauro baigiamasis darbas yra susijęs su galios elektronikos įrangos kūrimu. Darbas yra parengtas taip, kad jo atskiras dalis būtų galima naudotis besimokant galios elektronikos dalyką. Studentai atskiras dalis gali studijuoti kaip papildomą teorinę medžiagą, matydami jos praktinį išpildymą. Tuo tikslu darbe yra aprašomi atskiri elektronikos sistemos komponentai (schemos, loginiai elementai ir kiti puslaidininkiai prietaisai). Ultragarsinė sistema - tai puiki priemonė nuo šunų. Atliekant elektrinius montavimo darbus lauko sąlygomis, tikrinant elektros komponentus gyvenamuosiuose būstuose ar mėgstantiems pabėgioti miškeliuose, kuriuose gausu nepririštų šunų, ši sistema tikrai veiksminga. Sistema kompaktiška, telpa kišenėje ar prisisegant prie diržo. Veikimo principas - paspaudus mygtuką skleidžiamas ultragarsas, kurio negirdi žmogus, bet kuris labai nepatinka šunims. Pakanka nukreipti į gyvūną ir jis nubėga lyg įgeltas. Veiksmingiausiais 4-5 metrų atstumu. Nauja mokomoji įranga brangiai kainuoja, todėl siekiama sukurti ir išbandyti sistemą mokymo tikslams, kuri būtų suderinta su galios elektronikos dalyko mokymo programa. Darbe aprašomi schemos komponentai ir parametrų parinkimas, siekiant juos tarpusavyje suderinti ir užtikrinti jų tinkamą veikimą. / There are many different situations in which ultrasonic devices can be used by different people in different situations. People who might benefit from having an ultrasonic system in particular are: • Field service electrical engineers. • Inspectors of electrical installations. • People with an excessive fear of dogs. • Joggers. • Bicyclists. • Dog trainers. The system produces a high frequency sound only audible to dogs but not to humans, so using the device will not bother other people. The ultrasonic device will stop unwanted dogs from approaching you at approximately up to 15 feet, helping you to stop a fierce looking dog from getting close to you. The electronic device can be used not just to keep dogs away but also to train them. Post men who sometimes have to deal with dogs in and around homes. This type of device was originally used when training dogs but as the technology developed, it could also be used to scare dogs off if needed. When the device sounds the high frequency tone it will keeps dogs away at a distance of up to 15 feet. The ultrasonic system must never be used for any longer than absolutely necessary and should only be used for a second. The high tones are uncomfortable to an animal and as the idea is to chase the dog away, only short tones are effective. During the development of the thesis, the above mentioned ultrasonic system has been produced. Its appropriate operation was tested using an oscillograph (the signals of the electrical generation chain... [to full text]

Objective: Ultrasound is used increasingly in swallowing research because it can be a non-invasive, repeatable and cost effective measure of swallowing dynamics and rehabilitative effects. However unstable head position and transducer movement while imaging may result in measurement error that is substantive enough to bias research results. This study investigated the variation in measures of hyoid displacement and submental muscle size within and across three sessions using two methods of acquisition. Methods: Twenty-four healthy participants over the age of 50 attended three sessions. In each session, five dynamic video clips of hyoid movement and five static images of submental muscles were imaged in 2D ultrasound using two acquisition methods. One method involved manual hand-held stabilisation of the transducer and the other method involved a custom-designed stand for stabilisation of the transducer and participant. Hyoid displacement was measured as a percent change between measures made at rest and at maximal excursion. Additionally, cross sectional area (CSA) measurements were made of the paired geniohyoid and the left and right anterior belly of digastric (ABD) muscles at rest. Results: Out of 720 possible measures of hyoid displacement, 675 measures were analysed. There were no significant order effects of session or trial with changes that were <1% and no greater 4.5% for session and no greater than 1.5% for trial from estimated baseline measures. There was a significant effect of method (p<.01), with a systematic decrease in stand measures that were <9.5% and no greater than 16% from estimated baseline measures. Variance was larger across sessions than within sessions. The stand condition was more variable than the hand-held condition for measures of hyoid displacement. Out of a total of 2160 possible measures of submental muscle size, 555 measures of geniohyoid and 1408 measures of ABD muscles were analysed. There were no significant order effects of session, trial or method in geniohyoid muscle measures. The estimated order effects of session were <3% and no greater than 13%, and trials were <0.4% and no greater than 0.7% from estimated baseline measures. There were no significant order effects of session and method in ABD muscle measures with order effects of session that were <2% and no greater than 5.5%. There were significant effects of trial (p<.01) in both ABD muscles with a small systematic increase that was <0.5% and no greater than 0.8%. Variance was larger across sessions than within sessions in all measures of submental muscle size. The stand condition was less variable than the hand-held condition for all measures of submental muscle size. Conclusion: The results from this study provide guidance to researchers who intend to use repeated measures from ultrasound imaging as an outcome measure in swallowing research. The large variability within and across participants in measures of hyoid displacement and geniohyoid muscle size may require further investigation. When the variations described in this current study are considered in the measures of the ABD muscle size then it can be a valuable measure of rehabilitative techniques.

The aim was to explore the possibility to diagnose retained placental tissue and other placental complications with 3D ultrasound and to investigate the impact of previous caesarean section on placentation in forthcoming pregnancies. 3D ultrasound was used to measure the volumes of the uterine body and cavity in 50 women with uncomplicated deliveries throughout the postpartum period. These volumes were then used as reference, to diagnose retained placental tissue in 25 women with secondary postpartum haemorrhage. All but three of the 25 women had retained placental tissue confirmed at histopathology. The volume of the uterine cavity in women with retained placental tissue was larger than the reference in most cases, but even cavities with no retained placental tissue were enlarged (Studies I and II). Women with their first and second birth, recorded in the Swedish medical birth register, were studied in order to find an association between previous caesarean section and retained placenta. The risk of retained placenta with heavy bleeding (&gt;1,000 mL) and normal bleeding (≤1,000 mL) was estimated for 19,459 women with first caesarean section delivery, using 239,150 women with first vaginal delivery as controls. There was an increased risk of retained placenta with heavy bleeding in women with previous caesarean section (adjusted OR 1.61; 95% CI 1.44-1.79). There was no increased risk of retained placenta with normal bleeding (Study III). Placental location, myometrial thickness and Vascularisation Index were recorded on 400 women previously delivered by caesarean section. The outcome was retained placenta and postpartum haemorrhage (≥1,000 mL). There was a trend towards increased risk of postpartum haemorrhage for women with anterior placentae. Women with placenta praevia had an increased risk of retained placenta and postpartum haemorrhage. Vascularisation Index and myometrial thickness did not associate (Study IV). In conclusion: 3D ultrasound can be used to measure the volume of the uterine body and cavity postpartum, but does not increase the diagnostic accuracy of retained placental tissue. Previous caesarean section increases the risk of retained placenta in subsequent pregnancy, and placenta praevia in women with previous caesarean section increases the risk for retained placenta and postpartum haemorrhage.