Non Linear Ultrasound Doppler and the Detection of Targeted Contrast Agents

One of the main challenges in molecular imaging with targeted contrast agents is the detection and discrimination of attached agents from the rest of the signals originating from freely flowing agents and tissue. The aim of this thesis was to develop methods for the detection of targeted microbubbles. One approach consisted of investigating the use of nonlinear Doppler for this purpose. Nonlinear Doppler enables the differentiation of moving from non-moving and linear from nonlinear scattering. Targeted microbubbles are static and nonlinear scatterers and they should be detected using this technique. A novel nonlinear Doppler technique: Pulse subtraction Doppler, was developed and compared to pulse inversion Doppler. It is shown that both techniques lead to similar Doppler spectra and depending on the medical applications and the equipment limitations, both techniques have benefits. This served as a starting point for the derivation of a generalised nonlinear Doppler technique, based on combined linear pulse pair sequences and tested in a simulation study. The response from a single microbubble was simulated for different pulse combinations and the pulse sequences were compared with regards to criteria specific to imaging requirements. It was shown that depending on initially set criteria, such as transmitted energy, mechanical index or scanner characteristics, certain pulse combinations offer alternatives to the current imaging modalities and allow to take into account specific constrains due to the targeted application/equipment. Furthermore, the proposed approach is directly applicable in a strict non linear imaging approach, without Doppler processing. An in vitro phantom was designed in order to assess pulse subtraction Doppler for the detection and discrimination of static nonlinear microbubbles in the presence of free flowing ones. It was shown that pulse subtraction Doppler enables such discrimination and the practicability for in vivo situations is discussed. The pulse subtraction Doppler sequences were also tested on a phantom containing magnetic bubbles. It was shown that the magnetic bubbles can be immobilised through a magnetic field to a specific region of interest under flow conditions. The bubbles also showed to be acoustically detectable and to scatter linearly at diagnostic driving pressures. Preliminary work regarding experimental biotinylated microbubbles and their attachment to streptavidin coated surfaces is also presented. Due to their proximity to a wall, researchers have found that targeted microbubbles exhibit different acoustic signatures compared to free ones and this knowledge can improve their detection techniques. The behaviour of microbubbles against a membrane of varying stiffness was also studied through high speed camera observations. It was found both experimentally and by comparison to theoretical modelling that within the stiffness range of human blood vessels the change in acoustical behaviour of microbubbles is negligible. This thesis has taken two complementary research approaches which have shown to constitute advancements for the detection and discrimination of targeted microbubbles

Takuahi: Te oriori mō Tāmaunga-o-te-rangi - Mana Atua, mana Whenua, Mana Tangata

E roa nei tātau te Māori nō ngā wā o Hawaiki e tito ana i te waiata, i te haka, i te oriori, i te mōteatea hei waka kawe i ngā kōrero tuku iho ki ngā whakatipuranga hou. He putuputu tonu ngā tūmomo karere, ka raua atu ki roto i wēnei momo titonga waiata a te Māori. Ka whārikihia e ngā tohunga kaitito ngā karere nei mā te reo kīwaha, mā te reo whakataukī, mā te reo auaha hei kura huna. Mei māmā te kimi, ka tohunga katoa ngā Māori. Kai te aroaro o te tuhingaroa nei, ka ketuketu i tētahi o ngā oriori o Ngāti Porou, otiā, nō Te Whānau-a-Hinerupe, ko te oriori mō Tāmaunga-o-te-rangi, nā Te Māperetahi. Mā konei ake e ruku atu ai ki te raparapa i ngā kura huna e whakatauira ana i te mana Atua, mana whenua, mana tangata hei mana ahi kā. Mā tēnā hoki e whakatauira te mana ahi kā, kai a Tama, otiā, hei tauira atu ki ngā uri o Te Whānau-a-Hinerupe i tō rātau ake ahi kā roa ki Te Kawakawa mai Tawhiti. Ko ngā kōrero kua kohingia, he kōrero nō ngā tāngata e mōhio ana ki ngā tūmomo mana, ā, ki ngā kōrero e pā ana ki te oriori nei. Ka iringia wēnei rau kōrero hei whakarākei tonu i te pae tapu o Te Whānau-a-Hinerupe

Pulse subtraction Doppler

Recent advances have demonstrated the feasibility of molecular imaging using targeted microbubbles and ultrasound. One technical challenge is to selectively detect attached bubbles from those freely flowing bubbles and surrounding tissue. Pulse Inversion Doppler is an imaging technique enabling the selective detection of both static and moving ultrasound contrast agents: linear scatterers generate a single band Doppler spectrum, while non-linear scatterers generate a double band spectrum, one being uniquely correlated with the presence of contrast agents and non-linear tissue signals. We demonstrate that similar spectrums, and thus the same discrimination, can be obtained through a Doppler implementation of Pulse Subtraction. This is achieved by reconstructing a virtual echo using the echo generated from a short pulse transmission. Moreover by subtracting from this virtual echo the one generated from a longer pulse transmission, it is possible to fully suppress the echo from linear scatterers, while for non-linear scatterers, a signal will remain, allowing classical agent detection. Simulations of a single moving microbubble and a moving linear scatterer subject to these pulses show that when the virtual echo and the long pulse echo are used to perform pulsed Doppler, the power Doppler spectrum allows separation of linear and non-linear moving scattering. Similar results are obtained on experimental data acquired on a flow containing either microbubble contrast agents or linear blood mimicking fluid. This new Doppler method constitutes an alternative to Pulse Inversion Doppler and preliminary results suggest that similar dual band spectrums could be obtained by the combination of any non-linear detection technique with Doppler demodulation.</p

Differences in reproductive risk factors for breast cancer in middle-aged women in Marin County, California and a sociodemographically similar area of Northern California

<p>Abstract</p> <p>Background</p> <p>The Northern California county of Marin (MC) has historically had high breast cancer incidence rates. Because of MC's high socioeconomic status (SES) and racial homogeneity (non-Hispanic White), it has been difficult to assess whether these elevated rates result from a combination of established risk factors or other behavioral or environmental factors. This survey was designed to compare potential breast cancer risks and incidence rates for a sample of middle-aged MC women with those of a demographically similar population.</p> <p>Methods</p> <p>A random sample of 1500 middle-aged female members of a large Northern California health plan, half from Marin County (MC) and half from a comparison area in East/Central Contra Costa County (ECCC), were mailed a survey covering family history, reproductive history, use of oral contraceptives (OC) and hormone replacement therapy (HRT), behavioral health risks, recency of breast screening, and demographic characteristics. Weighted data were used to compare prevalence of individual breast cancer risk factors and Gail scores. Age-adjusted cumulative breast cancer incidence rates (2000–2004) were also calculated for female health plan members aged 40–64 residing in the two geographic areas.</p> <p>Results</p> <p>Survey response was 57.1% (n = 427) and 47.9% (n = 359) for MC and ECCC samples, respectively. Women in the two areas were similar in SES, race, obesity, exercise frequency, current smoking, ever use of OCs and HRT, age at onset of menarche, high mammography rates, family history of breast cancer, and Gail scores. However, MC women were significantly more likely than ECCC women to be former smokers (43.6% vs. 31.2%), have Ashkenazi Jewish heritage (12.8% vs. 7.1%), have no live births before age 30 (52.7% vs. 40.8%), and be nulliparous (29.2% vs. 15.4%), and less likely to never or rarely consume alcohol (34.4% vs. 41.9%). MC and ECCC women had comparable 2000–2004 invasive breast cancer incidence rates.</p> <p>Conclusion</p> <p>The effects of reproductive risks factors, Ashkenazi Jewish heritage, smoking history, and alcohol consumption with regard to breast cancer risk in Marin County should be further evaluated. When possible, future comparisons of breast cancer incidence rates between regions should adjust for differences in income and education in addition to age and race/ethnicity, preferably by using a sociodemographically similar comparison group.</p

Une demeure "dans son jus"? Réflexions autour des partis pris de présentation et de conservation du mobilier historique en Provence - Par Alexandre MAHUE

« Une demeure dans son jus » ? Réflexions autour des partis pris de présentation et de conservation du mobilier historique en Provence Par Alexandre Mahue, doctorant en Histoire de l'Art (UMR TELEMMe 7303- AMU CNRS L’Histoire du mobilier et des objets d’Art, de leurs provenances et de leurs modalités de conservation et d’exposition est souvent appréhendée comme celle d’un phénomène résiduel et anecdotique, éclipsé par l’importance accordée à l’étude du décor intérieur. Pourtant, le mobilier c..

Les Forbin au XVIIIe siècle, fastes et rayonnement d'une famille provençale

International audienceThe Forbin family is one of the most prestigious family of Provence during the 17th and 18th centuries. Their castles, private mansions and other properties are remarkable and were imbued by their historical and social importance in France. Organized thanks to the City of Aix-en-Provence and the association "Les Amis des Salons et Jardins d'Olivary", the study day that was devoted to this family in the town-hall of Aix-en-Provence gathered specialists and students and revealed its predominant role in History.Brillants mécènes, tour à tour bâtisseurs et collectionneurs, les Forbin ont compté dans leurs rangs des parlementaires fameux, des militaires distingués, des femmes d'esprit et des ecclésiastiques célèbres. Ils illustrèrent la Provence par leurs résidences, leurs commandes artistiques et leurs ambitions. Organisée en partenariat avec la Ville d'Aix-en-Provence et les Amis des Salons et Jardins d'Olivary, la journée d'étude du 16 juin 2017 a réuni plusieurs spécialistes qui, à l'aune des découvertes les plus récentes, ont mis en lumières la place prépondérante de cette famille provençale dans la France du XVIIIe siècle

Construire un hôtel particulier « à la Parisienne » : le chantier de l’hôtel de Villevrain, entre cour et jardin (1748-1754)

International audienc

La famille de Castellane au XVIIIe siècle

International audienceFamille de premier plan en Provence, la famille de Castellane a joué un rôle majeur dans les sphères politiques, militaires et artistiques de la région sous l'Ancien-Régime. Elle est à l'origine de plusieurs châteaux en Haute-Provence, dont le château d'Esparon de Verdon qui offre une architecture et des décors aussi complexes que spectaculaires. Après avoir identifié l'architecte à qui l'on doit la reconstruction d'une grande partie du château, les recherches menées au sein de dépôts d'archives publics et des archives privées de la famille de Castellane jusqu'alors inexploitées offrent une étude attentive du rapport de cette famille aux commandes architecturales, décoratives et mobilières qu'elle mènera au XVIIIe siècle. Par les relations privilgiées que les Castellane entretiendront pendant le siècle des Lumières avec les familles de Grignan et de Sévigné avec lesquelles ils sont très directement alliés, cet article ouvre une série de pistes de recherches inédites sur l'art de vivre d'une noblesse d'épée au prestige et au patrimoine incomparables

Les châteaux de Provence au XVIIIe siècle : expression architecturale et culturelle d'une société d'Ancien-Régime (extraits)

This study of the castles of Provence in the 18th century focuses on a corpus of 238 monuments of this period, so far very unevenly documented. Through an approach that is both serial and typological, it crosses archives and a survey on the scale of the entire territory of this province in the 18th century, today covered by five counties. The architectural analysis, the study of the layout parts and the the remaining interior decorations make it possible to appreciate common characteristics, to identify local particularities and to note significant evolutions. This period is characterized by many ambiguities, due to the importance that the owners of these buildings have at the same time of the seigniorial and noble reaction as well as the progressive diffusion of the Enlightenment, in particular physiocracy. The castles that make up this heterogeneous corpus largely reflect this duality. Academic architecture is poorly represented, in favour of structures mostly marked by the continuity of many forms and architectural traditions, sometimes inhabited by subtle reminiscences. If an obvious conservatism can be observed in terms of construction, the study of the changes in the layout and the numerous clues provided by the interior decoration tend to prove that the most educated and wealthy fringe of this noble group was nevertheless in concordance with its era. Alongside opulent townhouses, these polymorph castles assert themselves as the privileged support of a renewed thirst for nobility and prestige.Cette étude des châteaux de Provence au XVIIIe siècle s’intéresse à un corpus de référence de 238 édifices, jusqu’à présent très inégalement documentés. Par une approche à la fois sérielle et typologique, elle croise des données archivistiques et une enquête de terrain à l’échelle du territoire de cette province au XVIIIe siècle, aujourd’hui couvert par cinq départements. L’analyse architecturale, l’examen des partis distributifs et l’étude des décors intérieurs subsistants permet d’apprécier des caractéristiques communes, de dégager des particularismes locaux et de noter des évolutions significatives. Cette période est en outre caractérisée par des ambiguïtés nombreuses, tenant à l’importance que revêt concomitamment chez les propriétaires de ces édifices, la réaction seigneuriale et nobiliaire ainsi que la diffusion progressive de l’Esprit des Lumières, en particulier le courant physiocratique. Les châteaux qui composent ce corpus hétérogène reflètent pour une large part cette dualité. L’architecture savante et académique y est peu représentée, au profit de structures majoritairement marquées par la continuité de certaines formes et traditions architecturales, parfois habitées par de subtiles réminiscences. Si un conservatisme manifeste peut être observé en matière de plans et de construction, l’étude des mutations de la distribution et les indices nombreux que fournit le décor intérieur tendent à prouver que la frange la plus lettrée et la plus fortunée de ce groupe nobiliaire s’inscrivait néanmoins dans l’actualité culturelle de son temps. En parallèle d’hôtels particuliers opulents, ces châteaux protéiformes s’affirment comme le support privilégié d’une soif de noblesse et d’un prestige renouvelés

Le Château de la Barben. Mille ans d'art et d'histoire

The Castle of La Barben, located beetween Salon and Aix-en-Provence has been the property of the Forbin family, a prestigious dynasty of local lords, during more than six centuries. Thanks to is abundant collections, archives, paintings and pieces of furniture, the beauty of its gardens and the prestige of several historical figures that sojourned in this famous property, the castle of La Barben remains one of the most interesting monuments of Provence.Séjour de hauts personnages et résidence de grandes familles telles que les Pontevès et plus encore les Forbin pendant six siècles, cette propriété classée est l’un des monuments les plus emblématiques de Provence. Par la richesse de ses collections, la beauté de ses jardins et le souvenir de ses hôtes, la Barben s’affirme, du Roi René à la Princesse Pauline Borghèse, comme l'un des plus remarquables châteaux du Midi. L'ouvrage s'attache tant aux personnages historiques qui ont durablement marqué les lieux qu'aux décors intérieurs et à l'architecture de ce monument complexe.