Application of hyperpolarised Helium-3 in lung functional magnetic resonance imaging

Looking inside the lungs without the danger of ionizing radiation side effects became available with magnetic resonance imaging using hyperpolarised noble gases. This technique has the potential to become a real tool for assessing in vivo ventilation, perfusion and even lung microstructure. The work covered in this research was aimed to improve the existing method for 3He polarisation and open the possibility to develop new modalities to probe the lung microstructure that could then be used in clinical trials. For this purpose, the polarisation facility was remodeled and new components were added. The rest of the work was focused on developing diffusion techniques that are more appropriate for the assessment of lung diseases. The improvement of the 3He polarisation facility consisted in the optimization of the gas flow path, implementation of a new dispensing method and new controlling protocol. The capacity of the polarisation system was increased by using a more powerful laser. The outcome of this was an increase in polarisation rate and a significant reduction of the dispensing time. Altogether this allow for clinical studies to be performed without too much delay. A clinical study aimed to distinguish differences between children born at term and premature was started on 70 volunteers. Three methods for measuring diffusion were used : spin echo diffusion weighted method, SPAMM tagging and MR diffusion spectroscopy. The first was previously used in the group and the last two were developed during this research. The results were correlated with basic pulmonary functional tests(spirometry and plethysmography) and also with the multiple breaths nitrogen wash-out results. No differences were found in the two groups. The results don’t agree with the current theories on lung growth and suggest that alveolarisation occurs even after the age of 8, possibly up to adult age. This is very important to be investigated further due to its clinical importance

59th Annual Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 59th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Snowbird, Utah, July 22-27, 2018

Application of hyperpolarised Helium-3 in lung functional magnetic resonance imaging

Looking inside the lungs without the danger of ionizing radiation side effects became available with magnetic resonance imaging using hyperpolarised noble gases. This technique has the potential to become a real tool for assessing in vivo ventilation, perfusion and even lung microstructure. The work covered in this research was aimed to improve the existing method for 3He polarisation and open the possibility to develop new modalities to probe the lung microstructure that could then be used in clinical trials. For this purpose, the polarisation facility was remodeled and new components were added. The rest of the work was focused on developing diffusion techniques that are more appropriate for the assessment of lung diseases. The improvement of the 3He polarisation facility consisted in the optimization of the gas flow path, implementation of a new dispensing method and new controlling protocol. The capacity of the polarisation system was increased by using a more powerful laser. The outcome of this was an increase in polarisation rate and a significant reduction of the dispensing time. Altogether this allow for clinical studies to be performed without too much delay. A clinical study aimed to distinguish differences between children born at term and premature was started on 70 volunteers. Three methods for measuring diffusion were used : spin echo diffusion weighted method, SPAMM tagging and MR diffusion spectroscopy. The first was previously used in the group and the last two were developed during this research. The results were correlated with basic pulmonary functional tests(spirometry and plethysmography) and also with the multiple breaths nitrogen wash-out results. No differences were found in the two groups. The results don’t agree with the current theories on lung growth and suggest that alveolarisation occurs even after the age of 8, possibly up to adult age. This is very important to be investigated further due to its clinical importance

13th International Bologna Conference on Magnetic Resonance in Porous Media - Bologna 2016 Conference Handbook and Book of Abstracts

This conference series, founded at the University of Bologna in 1990 and now at the 13th edition, is devoted to the progress in Magnetic Resonance in Porous Media and in our understanding of Porous Media themselves, and to stimulate the contact among people from various parts of Academia and Industry. Researchers in Physics, Chemistry, Engineering, Life Sciences, Mathematics, Computer Sciences, and in Industrial Applications will benefit from exchange of ideas, experiences, and new approaches. Topics will include innovative techniques to study structure, behavior of fluids, and their interactions in every kind of natural and artificial porous materials, including rocks, cements, biological tissues, foodstuffs, wood, particle packs, sediments, pharmaceuticals, zeolites, and bioconstructs. New data acquisition and processing techniques are also expected to be strong features

Elasticity of Compressed Emulsions

The interfaces of bubbles and droplets imbue foams and emulsions with extraordinary mechanical and chemical properties. The remarkably large interfacial area of these structures controls their thermodynamics and makes them practical and functional materials. When these interfaces are forced to touch, they can turn a dispersion of one fluid in another into a solid. These solid-like properties are evident in common household products such as shaving foam and mayonnaise, and our ability to control the fluid and solid properties of these materials is essential to their function.Physic

BioMEMS for cardiac tissue monitoring and maturation

Diseases of the heart have been the most common cause of death in the United States since the middle of the 20th century. The development of engineered cardiac tissue over the last three decades has yielded human induced pluripotent stem cell-derived (hiPSC) cardiomyocytes (CMs), microscale “heart-on-a-chip” platforms, optical interrogation techniques, and more. Having spawned its own scientific field, ongoing research promises lofty goals to address the heart disease burden around the world, such as patient-specific disease models, and clinical trials on chip-based platforms. The greatest academic pursuit for engineered cardiac tissues is to increase their maturity, thereby increasing relevance to native adult tissue. Investigation of cardiomyocyte maturity necessitates the development of 3D-tissue compatible techniques for measuring and perturbing cardiac biology with enhanced precision. This dissertation focuses on the development of biological microelectromechanical systems (BioMEMS) for precision measurement and perturbation of cardiac tissue. We discuss three unique approaches to interfacing MEMS-based tools with cardiac biology. The first is a high resolution magnetic sensor, which directly measures the spatial gradient of a magnetic field. This has an ideal application in magnetocardiography (MCG), as the flux of ions during cardiac contractions produces measurable magnetic signals around the tissue and can be leveraged for noncontact diagnosis. The second is a highly functionalized heart-on-a-chip platform, wherein the mechanical contractions of cardiac microtissues can be simultaneously recorded and actuated. Contractile dynamics are leading indicators of maturity in engineered cardiac tissue and mechanical conditioning has shown recent promise as a critical component of cardiac maturation. The third is the imaging of contractile nanostructures in engineered cardiomyocytes at depth in a 3D microtissue. We use small angle X-ray scattering (SAXS) to discern the periodic arrangement of myofilaments in their native 3D environment. We enable a significant structural analysis to provide insight for functional maturation. Enabling these three thrusts required developing two supporting technologies. The first is the engineered control of dynamic second order systems, a foundational element of all our MEMS and magnetic techniques. We demonstrate numerous algorithms to improve settling time or decrease dead-time such that samples with fast temporal effects can be measured. The second is a microscale gluing technique for integrating myriad of materials with MEMS devices, yielding unique sensors and actuators.2022-05-15T00:00:00

13th International Bologna Conference on Magnetic Resonance in Porous Media - Bologna 2016 Conference Handbook and Book of Abstracts

This conference series, founded at the University of Bologna in 1990 and now at the 13th edition, is devoted to the progress in Magnetic Resonance in Porous Media and in our understanding of Porous Media themselves, and to stimulate the contact among people from various parts of Academia and Industry. Researchers in Physics, Chemistry, Engineering, Life Sciences, Mathematics, Computer Sciences, and in Industrial Applications will benefit from exchange of ideas, experiences, and new approaches. Topics will include innovative techniques to study structure, behavior of fluids, and their interactions in every kind of natural and artificial porous materials, including rocks, cements, biological tissues, foodstuffs, wood, particle packs, sediments, pharmaceuticals, zeolites, and bioconstructs. New data acquisition and processing techniques are also expected to be strong features

Design and performance analysis of a picosecond-pulsed laser raman spectrometer for fluorescence rejection in raman spectroscopy

Many attempts have been made to reduce fluorescence backgrounds in Raman spectra. A critical appraisal of fluoresence rejection techniques reveals that while many techniques are available which improve the Raman/fluorescence ratio (R/F), very few actually increase the spectral signal/noise (R/N), which is the most important parameter. Temporal-resolution of Raman and fluorescence photons was investigated in this laboratory, using a picosecond-laser system and gated photon detection. Two detection methods were evaluated. The first, an intensified diode array detector (DAD), could be gated "on" for periods of ca. 5 ns, at rates of up to 5kHz. This gave a 5-fold increase in R/F, but a slight reduction in R/N, for a fluorescor with τ(_f) ̴̱ 1O.5 ns. The R/N degradation arose as a result of the low laser output intensity at kHz pulse rates, rather than inefficiency in fluorescence rejection. The second method used a continuously-operated photomultiplie tube (PMT), and time-correlated photon counting with ca. 1 ns timing-resolution. This yielded R/F and R/N improvements of ca. 15 and 3 respectively (τ(_f) ̴̱ 12 ns).Although efficient fluorescence rejection was obtained with each system, the corresponding R/N enhancements were not practically significant. However, the development of theoretical models describing the performance of each system has identified modifications which should give valuable improvements. These include the use of a laser with MW peak powers at kHz pulse rates (DAD system), and use of a microchannel-plate PMT with 50 ps timing resolution. When these (and other) modifications are made, significant R/N enhancements (ca. 7 and 13 (DAD and PMT systems respectively)) are expected, thus enabling the study of the majority of "real world" samples. In addition, the limiting theoretical and practical performance of time-resolved rejection is considered, and several hitherto unreported aspects of the behaviour of the laser and detection systems are discussed. Other techniques were also evaluated, in particular utilising the differing Raman and fluorescence response to variations in laser intensity. While the non-linear fluorescence responseto intensity variations of cw lasers has been previously exploited, simple calculations indicate that the use of high-powered pulsed sources could allow discrimination at ca. 100- fold lower average powers. However, a satisfactory test of the calculations requires the construction of apparatus not presently available in this .laboratory

52nd Rocky Mountain Conference on Analytical Chemistry

Final program, abstracts, and information about the 52nd annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Snowmass, Colorado, August 1-5, 2010