Breast cancer is the most common cancer and the second leading cause of cancer death among women. About 1 in 8 U.S. women (about 12%) will develop invasive breast cancer over the course of their lifetime. Existing methods of early detection of breast cancer include mammography and palpation, either by patient self-examination or clinical breast exam. Palpation is the manual detection of differences in tissue stiffness between breast tumors and normal breast tissue. The success of palpation relies on the fact that the stiffness of breast tumors is often an order of magnitude greater than that of normal breast tissue, i.e., breast lesions feel ''hard'' or ''lumpy'' as compared to normal breast tissue. A mammogram is an x-ray that allows a qualified specialist to examine the breast tissue for any suspicious areas. Mammography is less likely to reveal breast tumors in women younger than 50 years with denser breast than in older women. When a suspicious site is detected in the breast through a breast self-exam or on a screening mammogram, the doctor may request an ultrasound of the breast tissue. A breast ultrasound can provide evidence about whether the lump is a solid mass, a cyst filled with fluid, or a combination of the two. An invasive needle biopsy is the only diagnostic procedure that can definitely determine if the suspicious area is cancerous. In the clinic, 80% of women who have a breast biopsy do not have breast cancer. Most women with breast cancer diagnosed will have some type of surgery to remove the tumor. Depending on the type of breast cancer and how advanced it is, the patient might need other types of treatment as well, such as chemotherapy and radiation therapy. Image-guided minimally-invasive treatment of localized breast tumor as an alternative to traditional breast surgery, such as high intensity focused ultrasound (HIFU) treatment, has become a subject of intensive research. HIFU applies extreme high temperatures to induce irreversible cell injury, tumor apoptosis and coagulative necrosis. Compared with conventional surgical procedures the main advantages of HIFU ablation lie in the fact that it is non-invasive, less scarring and less painful, allowing for shorter recovery time. HIFU can be guided by MRI (MRgFUS) or by conventional diagnostic ultrasound (USgFUS). Worldwide, thousands of patients with uterine fibroids, liver cancer, breast cancer, pancreatic cancer, bone tumors, and renal cancer have been treated by USgFUS. In this dissertation, the objective is to develop an integrated Harmonic Motion Imaging guided Focused Ultrasound (HMIgFUS) system as a clinical monitoring technique for breast HIFU with the added capability of detecting tumors for treatment planning, evaluation of tissue stiffness changes during HIFU ablation for treatment monitoring in real time, and assessment of thermal lesion sizes after treatment evaluation. A new HIFU treatment planning method was described that used oscillatory radiation force induced displacement amplitude variations to detect the HIFU focal spot before lesioning. Using this method, we were able to visualize the HMIgFUS focal region at variable depths. By comparing the estimated displacement profiles with lesion locations in pathology, we demonstrated the feasibility of using this HMI-based technique to localize the HIFU focal spot and predict lesion location during the planning phase. For HIFU monitoring, a HIFU lesion detection and ablation monitoring method was first developed using oscillatory radiation force induced displacement amplitude variations in real time. Using this method, the HMIgFUS focal region and lesion formation were visualized in real time at a feedback rate of 2.4 Hz. By comparing the estimated lesion size against gross pathology, the feasibility of using HMIgFUS to monitor treatment and lesion formation without interruption is demonstrated. In order to reduce the imaging time, it is shown in this dissertation that using the steered FUS beam, HMI can be used to image a 2.3 times larger ROI without requiring physical movement of the transducer. Using steering for HMI can be used to shorten the total imaging duration without requiring physical movement of the transducer. For the application of breast tumor, HMI and HMIgFUS were optimized and applied to ex vivo breast tissue. The results showed that HMI is experimentally capable of mapping and differentiating stiffness in normal and abnormal breast tissues. HMIgFUS can also successfully generate thermal lesions on normal and pathological breast tissues. HMI has also been applied to post-surgical breast mastectomy specimens to mimic the in vivo environment. In the end, the first HMI clinical system has been built with added capability of GUP-based parallel beamforming. A clinical trial has been approved at Columbia University to image breast tumor on patient. The HMI clinical system has shown to be able to map fibroadenoma mass on two patients with valid HMI displacement. The study in this dissertation may yield an early-detection technique for breast cancer without any age discrimination and thus, increase the survival rate.

An experiment currently underway at BYU is designed to test whether the size of a free electron wave packet affects the character of scattered radiation. Using a semi-classical argument wherein the wave packet is treated as a diffuse charge distribution, one would expect strong suppression of radiation in the direction perpendicular to the propagating field as the wave packet grows in size to be comparable to the wavelength of the driving field. If one disallows the interaction of the wave packet with itself, as is the case when calculating the rate of emission using QED, then regardless of size, the electron wave packet radiates with the strength of a point-like emitter. In support of this experiment, we explore a variety of physical parameters that impact the rate of scattered photons. We employ a classical model to characterize the exposure of electrons to high-intensity laser light in a situation where the electrons are driven by strong ponderomotive gradients. Free electrons are modeled as being donated by low-density helium, which undergoes strong-field ionization early on in the pulse or during a pre-pulse. When exposed to relativistic intensities (i.e. intensities sufficient to cause a Lorentz drift at a significant fraction of c), free electrons experience a Lorentz drift that causes redshifting of the scattered 800 nm laser light. This redshift can be used as a key signature to discern light scattered from the more intense regions of the focus. We characterize the focal volume of initial positions leading to significant redshifting, given a peak intensity of 2 x 10^18 W/cm 2 , which is sufficient to cause a redshift in scattered light of approximately 100 nm. Under this scenario, the beam waist needs to be larger than several wavelengths for a pulse duration of 35 fs in order to ensure free electrons remain in the focus sufficiently long to experience intensities near the peak pulse intensity despite strong ponderomotive gradients. We compute the rate of redshifted scattered photons from an ensemble of electrons distributed throughout the focus and relate the result to the scattered-photon rate of a single electron. We also estimate to what extent the ionization process may produce unwanted light in the redshifted spectral region that may confound the measurement of light scattered from electrons experiencing intensities greater than 1.5 x 10^18 W/cm^2.

Bakgrund: Kvinnor tränar mer nu än tidigare och många av dessa blir även gravida. Träning under graviditet har många hälsofördelar. De flesta råd angående träning under graviditet handlar om träning på måttlig intensitet samt motverkande av graviditetskomplikationer. En del kvinnor tränar mer än dessa rekommendationer. Därav finns råd och rekommendationer för elitatleter samt forskning på högintensiv träning under graviditet. Det är dock oklart ifall dessa råd når ut till gravida kvinnor som tränar på högintensiv nivå. Syfte: Att undersöka om träningsmängd förändrats under graviditet hos friska kvinnor som tränat på högintensiv nivå innan graviditeten, samt hur kvinnorna upplevt den information om träning de fått under graviditet och var de fått informationen. Deltagare: Arton kvinnor (23–37 år) deltog i studien. Inklusionskriterier var förstföderska, gravid i tredje trimestern fram till fyra veckor postpartum, komplikationsfri graviditet och högintensiv träning minst tre gånger per vecka under minst ett år innan och fram till graviditeten, antingen kondition, styrka eller både och.    Metod: Deltagarna besvarade en webbenkät med 23 frågor. Frågorna handlade om träningsmängd under graviditet samt den information om träning deltagarna fått under graviditet. Resultat: De flesta kvinnorna minskade sin träningsmängd under graviditeten och många av kvinnorna saknade tillräcklig information för att kunna träna på önskad nivå. Information om träning kom främst från barnmorska. Konklusion: Träningsmängd hos friska motionsvana gravida kvinnor har minskat under graviditeten samtidigt som kvinnorna saknade tillräcklig träningsinformation. Kvinnorna fick information om träning under graviditet främst från barnmorska. Det går inte att säga om avsaknaden av information har påverkat träningsmängden men det kan vara intressant att undersöka i framtida studier. Fortsatt forskning på högintensiv träning under graviditet behövs för att kunna ge tillräcklig information till högintensivt tränande gravida kvinnor. / Background: Women exercises more now than before, and many of them become pregnant. Exercise during pregnancy has many health benefits. Most advice about exercise during pregnancy is about exercise at a moderate intensity and prevention of pregnancy complications. Some women exercise more than these recommendations. There are advice and recommendations for elite athletes and research on high intensity exercise during pregnancy. Although it is unclear if these advice reaches pregnant women who exercises at a high intensity level. Objective: To examine if the amount of exercise changed during pregnancy for healthy women who exercised at a high intensity level, how they had perceived the information about exercise during pregnancy they had received and where they got the information from. Participants: Eighteen women (23–37 years) participated in the study. Criteria for inclusion were first time pregnancy, pregnant in the third trimester up until four weeks postpartum, pregnancy without complications and exercise at a high intensity at least three times a week during at least one year before and up until the pregnancy, either cardio, strength or both. Method: The participants answered an online survey with 23 questions. The questions were about amount of exercise during pregnancy and the information about exercise the women had received during pregnancy. Results: Most of the women decreased their amount of exercise during pregnancy and many of the women lacked adequate information to be able to exercise at desired level. Information about exercise came mainly from midwifes. Conclusion: The amount of exercise in healthy exercising pregnant women have decreased during pregnancy at the same time as the women lacked adequate information about exercise. The women received information about exercise mainly from midwifes. It cannot be said if the lack of information has affected the amount of exercise but that would be interesting to investigate further in future studies. Continued research about high intensity exercise during pregnancy is needed to be able to give adequate information to pregnant women who exercises at a high intensity.

This study examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on left ventricular (LV) function in young, healthy men. Sixteen untrained men were randomly assigned to HIT (8-12 X 60:75 seconds cycling at 95-100%:10% V˙O2peak) and CMT (90-120 minutes cycling at 65% V˙O2peak) and assessed before and after six sessions of training. LV function was determined at rest and during submaximal exercise using two-dimensional and Doppler echocardiography. HIT and CMT improved V˙O2peak and induced plasma volume expansion to a similar magnitude. Although resting LV function did not change, increased exercise stroke volume and cardiac output was observed, secondary to increases in end-diastolic volume. Numerous ECHO-derived indices of diastolic performance were similarly enhanced during exercise in both groups. Short-term HIT and CMT elicit rapid increases in V˙O2peak and LV filling without global changes in systolic performance or cardiac morphology at rest.

This study examined the effects of short-term high-intensity interval training (HIT) and continuous moderate-intensity training (CMT) on left ventricular (LV) function in young, healthy men. Sixteen untrained men were randomly assigned to HIT (8-12 X 60:75 seconds cycling at 95-100%:10% V˙O2peak) and CMT (90-120 minutes cycling at 65% V˙O2peak) and assessed before and after six sessions of training. LV function was determined at rest and during submaximal exercise using two-dimensional and Doppler echocardiography. HIT and CMT improved V˙O2peak and induced plasma volume expansion to a similar magnitude. Although resting LV function did not change, increased exercise stroke volume and cardiac output was observed, secondary to increases in end-diastolic volume. Numerous ECHO-derived indices of diastolic performance were similarly enhanced during exercise in both groups. Short-term HIT and CMT elicit rapid increases in V˙O2peak and LV filling without global changes in systolic performance or cardiac morphology at rest.

This text pursues the causes and phenomena in the course of the collapse of the molten metal layer surrounding a keyhole which is full of vapor and liquid particles during the high energy laser or electron beam drilling process. And the formation mechanism of the pores for the drilling process, to study the collapse phenomenon of the liquid layer is essential. In the research the collapse of the keyhole is taken as approximated to a transition between the slug and annular two-phase flows in a vertical pipe of varying cross-section. We develop and solve a quasi-steady, one-dimensional model for two phase flow with the assumption that the mixture in the core homogenous, ignoring the friction of the liquid layer, regarding the flow in the keyhole as supersonic, considering the mass transfer of the liquid layer to the keyhole. Two-phase flow can be liquid particle entrainment characteristics, infiltration precipitation, divided into two regions. The collapse of keyhole resulted from the infiltration of the liquid particles is chained to the pore formation. Based on the realization of annular two phase flow, In this text, that the liquid into the holes in the physical properties and caused pores formation.

This study examined whether a high-intensity interval (IT) or a continuous steady-state (CT) exercise training program had the greatest effect on fat oxidation rates and fat mass loss in a population of untrained overweight and obese females. Thirteen female subjects (VO2peak 30.6 ± 1.29 ml.kg.min-1, BMI 29 ± 0.79, fat mass [FM] 33.3 ± 2.09 kg) were randomly assigned to either a CT (exercise at the relative intensity that elicits the maximal fat oxidation rate [FATmax] ) or an IT (intervals alternating 5 minutes at 40% and 85% VO2peak) training group that exercised approximately 1 hour, 3 days.week-1 for 10 weeks. Body composition assessments, peak oxygen uptake (VO2peak), FATmax and plasma free fatty acid (FFA) concentrations were examined pre- and post-training using dual-energy X-ray absorptiometry (DEXA), ParvoMedics gas analysis system and FFA half micro tests (Roche Diagnostics). No significant differences were found post-training in body weight (kg), body fat (%), fat-free mass, or fat mass (P>0.05). The relative exercise intensity that elicited FATmax was significantly increased from 35.3 ± 2.55% to 44.7 ± 3.56% in the IT group post-training (P <0.05). The maximal fat oxidation rate was determined at a higher relative exercise intensity after 10 weeks of a IT program compared with a CT program, which resulted in longer durations of fat oxidation during submaximal exercise bouts. These data suggest that an IT program induces a greater increase in the relative exercise intensity that elicits maximal fat oxidation after 10 weeks of training compared to a CT program in this population. Although body composition and FATmax were not altered, it is possible that through training induced metabolic adaptations from the IT program, intramuscular triacylglyceride (IMTG) contributions to fat oxidation at a given steady-state work rate could be increased post-training.

Aim The overall aim of this study was to develop a broader understanding on how to optimize the organization of aerobic endurance training programs, and especially how to better organize high-intensity training (HIT) and low intensity training (LIT) to give an optimum endurance performance progress. Method This study compared the effects of two different training organization methods in trained cross-country (XC) skiers and biathletes. During a 5 week intervention period, one group of athletes (n = 10, 7 men and 3 women, age 23 ± 9 years) performed block periodization (BP) training with 5-1-3-1-1 HIT sessions in the respective weeks. The other group of athletes(n = 9, 7 men and 2 women, age 22 ± 5) followed a more traditional periodization (TRAD) method performing 2-2-3-2-2 HIT sessions. LIT was interspersed between the HIT sessions so that both groups performed similar total volumes of HIT and LIT during the intervention period. Results The BP group increased relative and absolute VO2max (2.6 ± 3.6% and 2.0 ± 2.5%, P &lt; 0.05) and time to exhaustion (6.1 ± 6.4%, P &lt; 0.01). No changes were seen in the TRAD group on relative or absolute VO2max (0.8 ± 3.5% and -0.1 ± 3.0%) or time to exhaustion (-2.0 ± 7.7%). Mean effects size (ES) of the relative and absolute improvement in VO2max and time to exhaustion revealed small to moderate effects of performing BP training vs. TRAD training (ES range from 0.51 to 1.14). Conclusions This study indicates that organizing endurance training in XC skiers with block periodization training give better adaptations compared to performing traditional periodization training during a 5 week training period when performing similar volumes of high-intensity and low intensity training.

Laser micromachining has become increasing prominent in various industries given its speed, lack of tool wear, and ability to create features on the order of micrometres. Inherent stochastic variations from thermal ablation along with detrimental heat effects, however, limit the feasibility of achieving high precision. The high number of control parameters that make laser micromachining versatile also hinders optimization due to high exploration time. The introduction of high intensity nonlinear ablation leads to more precise cuts but at a much higher, often restrictive, cost. The work here shows that by combining an imaging technique frequently used in ophthalmology called optical coherence tomography (OCT) with a machining platform, in situ observation of ablation can be made. This combination, known as in-line coherent imaging (ICI), allows information to be gathered about the dynamics of the ablation process. Experimental results show that quality cutting of silicon can be achieved with thermal ablation and at a wavelength of 1070 nm. This result is surprising as silicon absorbs this wavelength very weakly at room temperature. It is shown here that a nonlinear thermal dependence in absorption allows a cascaded absorption effect to enable machining. With the aid of ICI, the model shown here is able to accurately predict the thermal ablation rate and help understand the ablation process. The high quality cutting achieved allows for a more cost efficient alternative to current techniques using ultraviolet diode-pumped solid state (UV DPSS) systems. Where thermal effects such as heat-affected zones (HAZ) cannot be overcome, high intensity nonlinear ablation allows the processing of lead zirconate titanate (PZT) for high frequency arrays (used in ultrasound applications) at speeds two orders of magnitude greater than found in the literature, and potential feature sizes (< 100 µm) in polymethyl methacrylate (PMMA) unachievable by thermal ablation. The ablation mechanism here is Coulombic explosion (CE), which is a non-thermal process. Coupled with demonstrated manual and automatic feedback abilities of ICI, the processes shown here may open up new avenues for fabrication. / Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2011-05-31 15:02:55.547

PURPOSE: To determine if participation in a short-term, high intensity physical education (PE) intervention that respected the multiple goals of the PE curriculum would result in any health- and/or fitness-related improvements for grade four and five students. METHODS: Seventy-six students were divided into a control and intervention group (CG & IG). During 15 successive classes, the IG participated in six minutes of high intensity activities while no changes were made to the structure of the CG’s PE class. Accelerometers and direct observation were used to quantify the percentage of moderate-to-vigorous physical activity (%MVPA). Health- and performance-related measures were assessed pre- and post-intervention. RESULTS: Students spent an average of 27% of their PE class engaged in MVPA. Within this category, the intervention was successful at increasing students’ VPA levels by 7.7%. Observations regarding pedagogical practices are also reported. CONCLUSIONS: Participating in a PE intervention can increase students’ PA levels without compromising the goals of the PE curriculum.