Many worlds and modality in the interpretation of quantum mechanics: an algebraic approach

Many worlds interpretations (MWI) of quantum mechanics avoid the measurement problem by considering every term in the quantum superposition as actual. A seemingly opposed solution is proposed by modal interpretations (MI) which state that quantum mechanics does not provide an account of what `actually is the case', but rather deals with what `might be the case', i.e. with possibilities. In this paper we provide an algebraic framework which allows us to analyze in depth the modal aspects of MWI. Within our general formal scheme we also provide a formal comparison between MWI and MI, in particular, we provide a formal understanding of why --even though both interpretations share the same formal structure-- MI fall pray of Kochen-Specker (KS) type contradictions while MWI escape them.Comment: submitted to the Journal of Mathematical Physic

Carbon Nanotubes Effect for Polymer Materials on Break Down Voltage

Epoxy resin composites reinforced to different types of carbon nano-particles have been fabricated. Carbon black (20, 30 and 40 wt. %), graphene (0.5 to 4 wt. %) and carbon nanotubes (CNT) (0.5 to 2 wt. %) were added with different weight percentages to epoxy. The dielectric strength of composites was tested in several conditions such as (dry, wet, low salinity and high salinity). The mechanical characterization showed that the nano-composite Polymer enhanced by using these particles in the tensile strength. Thermal gravimetric analysis shows effect of these nano-particles on the thermal structure of epoxy resin. Scanning Electron Microscopic test is used to characterize the dispersion of carbon nano-particles and to analysis the fractured parts in the nano scale

Photoacoustics for Cardiovascular Applications

In the thesis entitled Photoacoustic imaging for Cardiovascular Applications, two cardiovascular diseases were tackled, namely atrial fibrillation and coronary atherosclerosis. An imaging algorithm was also devised to enhance imaging target super-localization. Photoacoustic imaging is an imaging modality which provides molecular information, based on optical absorption and subsequent thermoelastic expansion resulting in detectable pressure waves with common ultrasonic detectors. Capability of imaging tissue molecular changes was shown relevant to enable real-time monitoring of lesion formation in catheter-based ablation for atrial fibrillation as well as to assess lipid content of atherosclerotic plaques in an anima

The Complements of Lower Cones of Degrees and the Degree Spectra of Structures

We study Turing degrees a for which there is a countable structure whose degree spectrum is the collection {x : x ≰ a}. In particular, for degrees a from the interval [0′, 0″], such a structure exists if a′ = 0″, and there are no such structures if a″ \u3e 0‴

Spectroscopic photoacoustic imaging of radiofrequency ablation in the left atrium

Catheter-based radiofrequency ablation for atrial fibrillation has long-term success in 60-70% of cases. A better assessment of lesion quality, depth, and continuity could improve the procedure’s outcome. We investigate here photoacoustic contrast between ablated and healthy atrial-wall tissue in vitro in wavelengths spanning from 410 nm to 1000 nm. We studied single-and multi-wavelength imaging of ablation lesions and we demonstrate that a two-wavelength technique yields precise detection of lesions, achieving a diagnostic accuracy of 97%. We compare this with a best single-wavelength (640 nm) analysis that correctly identifies 82% of lesions. We discuss the origin of relevant spectroscopic features and perspectives for translation to clinical imaging

AC133+ progenitor cells as gene delivery vehicle and cellular probe in subcutaneous tumor models: a preliminary study

<p>Abstract</p> <p>Background</p> <p>Despite enormous progress in gene therapy for breast cancer, an optimal systemic vehicle for delivering gene products to the target tissue is still lacking. The purpose of this study was to determine whether AC133+ progenitor cells (APC) can be used as both gene delivery vehicles and cellular probes for magnetic resonance imaging (MRI). In this study, we used superparamagentic iron oxide (SPIO)-labeled APCs to carry the human sodium iodide symporter (hNIS) gene to the sites of implanted breast cancer in mouse model. In vivo real time tracking of these cells was performed by MRI and expression of hNIS was determined by Tc-99m pertechnetate (Tc-99m) scan.</p> <p>Results</p> <p>Three million human breast cancer (MDA-MB-231) cells were subcutaneously implanted in the right flank of nude mice. APCs, isolated from fresh human cord blood, were genetically transformed to carry the hNIS gene using adenoviral vectors and magnetically labeled with ferumoxides-protamine sulfate (FePro) complexes. Magnetically labeled genetically transformed cells were administered intravenously in tumor bearing mice when tumors reached 0.5 cm in the largest dimension. MRI and single photon emission computed tomography (SPECT) images were acquired 3 and 7 days after cell injection, with a 7 Tesla animal MRI system and a custom built micro-SPECT using Tc-99m, respectively. Expression of hNIS in accumulated cells was determined by staining with anti-hNIS antibody. APCs were efficiently labeled with ferumoxide-protamine sulfate (FePro) complexes and transduced with hNIS gene. Our study showed not only the accumulation of intravenously administered genetically transformed, magnetically labeled APCs in the implanted breast cancer, but also the expression of hNIS gene at the tumor site. Tc-99m activity ratio (tumor/non-tumor) was significantly different between animals that received non-transduced and transduced cells (P < 0.001).</p> <p>Conclusion</p> <p>This study indicates that genetically transformed, magnetically labeled APCs can be used both as delivery vehicles and cellular probes for detecting <it>in vivo </it>migration and homing of cells. Furthermore, they can potentially be used as a gene carrier system for the treatment of tumor or other diseases.</p

Human Cord Blood-Derived AC133+ Progenitor Cells Preserve Endothelial Progenitor Characteristics after Long Term In Vitro Expansion

Stem cells/progenitors are central to the development of cell therapy approaches for vascular ischemic diseases. The crucial step in rescuing tissues from ischemia is improvement of vascularization that can be achieved by promoting neovascularization. Endothelial progenitor cells (EPCs) are the best candidates for developing such an approach due to their ability to self-renew, circulate and differentiate into mature endothelial cells (ECs). Studies showed that intravenously administered progenitors isolated from bone marrow, peripheral or cord blood home to ischemic sites. However, the successful clinical application of such transplantation therapy is limited by low quantities of EPCs that can be generated from patients. Hence, the ability to amplify the numbers of autologous EPCs by long term in vitro expansion while preserving their angiogenic potential is critically important for developing EPC based therapies. Therefore, the objective of this study was to evaluate the capacity of cord blood (CB)-derived AC133+ cells to differentiate, in vitro, towards functional, mature endothelial cells (ECs) after long term in vitro expansion.We systematically characterized the properties of CB AC133+ cells over the 30 days of in vitro expansion. During 30 days of culturing, CB AC133+ cells exhibited significant growth potential that was manifested as 148-fold increase in cell numbers. Flow cytometry and immunocytochemistry demonstrated that CB AC133+ cells' expression of endothelial progenitor markers was not affected by long term in vitro culturing. After culturing under EC differentiation conditions, cells exhibited high expression of mature ECs markers, such as CD31, VEGFR-2 and von Willebrand factor, as well as the morphological changes indicative of differentiation towards mature ECs. In addition, throughout the 30 day culture cells preserved their functional capacity that was demonstrated by high uptake of DiI fluorescently conjugated-acetylated-low density lipoprotein (DiI-Ac-LDL), in vitro and in vivo migration towards chemotactic stimuli and in vitro tube formation.These studies demonstrate that primary CB AC133+ culture contained mainly EPCs and that long term in vitro conditions facilitated the maintenance of these cells in the state of commitment towards endothelial lineage

Anterior eye surface changes following miniscleral contact lens wear

Purpose To quantify the effect of short-term miniscleral contact lens wear on the anterior eye surface of healthy eyes, including cornea, corneo-scleral junction and sclero-conjuctival area. Methods Twelve healthy subjects (29.9 ± 5.7 years) wore a highly gas-permeable miniscleral contact lens of 16.5 mm diameter during a 5-hour period. Corneo-scleral height profilometry was captured before, immediately following lens removal and 3 h after lens removal. Topography based corneo-scleral limbal radius estimates were derived from height measurements. In addition, elevation differences in corneal and scleral region were calculated with custom-written software. Sclero-conjuctival flattening within different sectors was analysed. Results Short-term miniscleral lens wear significantly modifies the anterior eye surface. Significant limbal radius increment (mean ± standard deviation) of 146 ± 80 μm, (p = 0.004) and flattening of −122 ± 90 μm in the sclero-conjuctival area, (p << 0.001) were observed immediately following lens removal. These changes did not recede to baseline levels 3 h after lens removal. The greatest anterior eye surface flattening was observed in the superior sector. No statistically significant corneal shape change was observed immediately following lens removal or during the recovery period. Conclusions Short-term miniscleral contact lens wear in healthy eyes does not produce significant corneal shape changes measured with profilometry but alters sclero-conjuctival topography. In addition, sclero-conjuctival flattening was not uniformly distributed across the anterior eye