Optimization of Wireless Power Transfer via Magnetic Resonance in Different Media

A wide range of non-destructive testing (NDT) methods for the monitoring the health of concrete structure has been studied for several years. The recent rapid evolution of wireless sensor network (WSN) technologies has resulted in the development of sensing elements that can be embedded in concrete, to monitor the health of infrastructure, collect and report valuable related data. The monitoring system can potentially decrease the high installation time and reduce maintenance cost associated with wired monitoring systems. The monitoring sensors need to operate for a long period of time, but sensors batteries have a finite life span. Hence, novel wireless powering methods must be devised. The optimization of wireless power transfer via Strongly Coupled Magnetic Resonance (SCMR) to sensors embedded in concrete is studied here. First, we analytically derive the optimal geometric parameters for transmission of power in the air. This specifically leads to the identification of the local and global optimization parameters and conditions, it was validated through electromagnetic simulations. Second, the optimum conditions were employed in the model for propagation of energy through plain and reinforced concrete at different humidity conditions, and frequencies with extended Debye's model. This analysis leads to the conclusion that SCMR can be used to efficiently power sensors in plain and reinforced concrete at different humidity levels and depth, also validated through electromagnetic simulations. The optimization of wireless power transmission via SMCR to Wearable and Implantable Medical Device (WIMD) are also explored. The optimum conditions from the analytics were used in the model for propagation of energy through different human tissues. This analysis shows that SCMR can be used to efficiently transfer power to sensors in human tissue without overheating through electromagnetic simulations, as excessive power might result in overheating of the tissue. Standard SCMR is sensitive to misalignment; both 2-loops and 3-loops SCMR with misalignment-insensitive performances are presented. The power transfer efficiencies above 50% was achieved over the complete misalignment range of 0°-90° and dramatically better than typical SCMR with efficiencies less than 10% in extreme misalignment topologies.

Utility and safety of invasive (fractional flow reserve) and non-invasive (cardiac magnetic resonance imaging) diagnostic tests in patients with NSTEMI

A prospective randomised controlled clinical trial of treatment decisions informed by invasive functional testing of coronary artery disease severity compared with standard angiography-guided management was implemented in 350 patients with a recent non-ST elevation myocardial infarction (NSTEMI) admitted to 6 hospitals in the National Health Service. The main aims of this study were to examine the utility of both invasive fractional flow reserve (FFR) and non-invasive cardiac magnetic resonance imaging (MRI) amongst patients with a recent diagnosis of NSTEMI. In summary, the findings of this thesis are: (1) the use of FFR combined with intravenous adenosine was feasible and safe amongst patients with NSTEMI and has clinical utility; (2) there was discordance between the visual, angiographic estimation of lesion significance and FFR; (3). The use of FFR led to changes in treatment strategy and an increase in prescription of medical therapy in the short term compared with an angiographically guided strategy; (4) in the incidence of major adverse cardiac events (MACE) at 12 months follow up was similar in the two groups. Cardiac MRI was used in a subset of patients enrolled in two hospitals in the West of Scotland. T1 and T2 mapping methods were used to delineate territories of acute myocardial injury. T1 and T2 mapping were superior when compared with conventional T2-weighted dark blood imaging for estimation of the ischaemic area-at-risk (AAR) with less artifact in NSTEMI. There was poor correlation between the angiographic AAR and MRI methods of AAR estimation in patients with NSTEMI. FFR had a high accuracy at predicting inducible perfusion defects demonstrated on stress perfusion MRI. This thesis describes the largest randomized trial published to date specifically looking at the clinical utility of FFR in the NSTEMI population. We have provided evidence of the diagnostic and clinical utility of FFR in this group of patients and provide evidence to inform larger studies. This thesis also describes the largest ever MRI cohort, including with myocardial stress perfusion assessments, specifically looking at the NSTEMI population. We have demonstrated the diagnostic accuracy of FFR to predict reversible ischaemia as referenced to a non-invasive gold standard with MRI. This thesis has also shown the futility of using dark blood oedema imaging amongst all comer NSTEMI patients when compared to novel T1 and T2 mapping methods.

Magnetic Resonance Imaging-Derived biomarkers of Isocitrate-Dehydrogenase mutation in diffuse gliomas: a conventional MR and Diffusion Weighted Imaging study.

The introduction of molecular criteria into the classification of diffuse gliomas has added interesting practical implications to glioma management. This has created a new clinical need for correlating imaging characteristics with glioma genotypes, also known as radiogenomics or imaging genomics. Whilst many studies have primarily focused on the use of advanced magnetic resonance imaging (MRI) techniques for radiogenomics purposes, conventional MRI sequences still remain the reference point in the study and characterization of brain tumours. Moreover, a different approach may rely on diffusion-weighted imaging (DWI) usage, which is considered a “conventional” sequence in line with recently published directions on glioma imaging. In a non-invasive way, it can provide direct insight into the microscopic physical properties of tissues. Considering that Isocitrate-Dehydrogenase gene mutations may reflect alterations in metabolism, cellularity, and angiogenesis, which may manifest characteristic features on an MRI, the identification of specific MRI biomarkers could be of great interest in managing patients with brain gliomas. My study aimed to evaluate the presence of specific MRI-derived biomarkers of IDH molecular status through conventional MRI and DWI sequences.

Correlations between cardiac magnetic resonance and histologic findings in Anderson Fabry disease

ABSTRACT Background Cardiac magnetic resonance (CMR) has been shown as promising diagnostic tool in Anderson-Fabry disease (AFD) cardiomyopathy due to its ability to detect fat deposits through lower native T1 values. However no histological validation has been provided to date. Objectives To correlate CMR and histologic findings in different cardiac stages of AFD focusing on T1 mapping. Methods Fifteen AFD patients (49 years [IQR 39-63], 60% females) undergoing CMR (cines, native T1 and T2 mapping, LGE and post-contrast T1 imaging) and endomyocardial biopsy (EMB, n=11) or septal myectomy (n=4), were retrospectively evaluated. Tissue specimens were analyzed with light/electron microscopy and vacuolization amount calculated as percentages of vacuolated myocytes and vacuolated myocyte area (%VMA) through a quantitative histomorphometric color-based analysis. Results In patients without increased indexed left ventricular mass (LVMi) at CMR (67%), T1 fell as %VMA increased (r= -0.883; p<0.001), whereas no clear relationship was evident once increased LVMi occurred (r= -0.501; p=0.389). At least 45% of vacuolized myocytes and 10% of VMA were needed for low T1 to occur. %VMA positively correlate with maximal wall thickness (MWT, r=0.860, p<0.0001) and LVMi (r= 0.762; p<0.001). Increased MWT and LVMi were present with at least 45% and 80% of vacuolated myocytes, respectively, and 18% and 22% of VMA. Conclusions This study demonstrated an inverse correlation between native T1 and the vacuolization amount in patients without increased LVMi at CMR, providing a histological validation of low native T1 in AFD. Importantly, a significant vacuolization burden was needed before low T1 and left ventricle hypertrophy occurred.

Non-invasive detection of acute cell-mediated graft rejection in paediatric heart transplant recipients: the role of cardiovascular magnetic resonance

Background and Aim: Acute cardiac rejection is currently diagnosed by endomyocardial biopsy (EMB), but multiparametric cardiac magnetic resonance (CMR) may be a non-invasive alternative by its capacity for myocardial structure and function characterization. Our primary aim was to determine the utility of multiparametric CMR in identifying acute graft rejection in paediatric heart transplant recipients. The second aim was to compare textural features of parametric maps in cases of rejection versus those without rejection. Methods: Fifteen patients were prospectively enrolled for contrast-enhanced CMR followed by EMB and right heart catheterization. Images were acquired on a 1,5 Tesla scanner including T1 mapping (modified Look-Locker inversion recovery sequence – MOLLI) and T2 mapping (modified GraSE sequence). The extracellular volume (ECV) was calculated using pre- and post-gadolinium T1 times of blood and myocardium and the patient’s hematocrit. Markers of graft dysfunction including hemodynamic measurements from echocardiography, catheterization and CMR were collated. Patients were divided into two groups based on degree of rejection at EMB: no rejection with no change in treatment (Group A) and acute rejection requiring new therapy (Group B). Statistical analysis included student’t t test and Pearson correlation. Results: Acute rejection was diagnosed in five patients. Mean T1 values were significantly associated with acute rejection. A monotonic, increasing trend was noted in both mean and peak T1 values, with increasing degree of rejection. ECV was significantly higher in Group B. There was no difference in T2 signal between two groups. Conclusion: Multiparametric CMR serves as a noninvasive screening tool during surveillance encounters and may be used to identify those patients that may be at higher risk of rejection and therefore require further evaluation. Future and multicenter studies are necessary to confirm these results and explore whether multiparametric CMR can decrease the number of surveillance EMBs in paediatric heart transplant recipients.

Sargassum Filipendula Alginate From Brazil: Seasonal Influence And Characteristics.

The aim of this work is focused on the extraction and characterization of the Brazilian seaweed Sargassum filipendula alginate. Alginates obtained at different seasons were characterized by liquid state nuclear magnetic resonance spectroscopy and scanning electron microscopy. The alginate extraction efficiency was about 20%. Different seasons of the year and different stages in the life cycle of Sargassum sp. in southeastern Brazil influenced the M/G and, consequently, the technological properties of extracted alginates.

A New Platinum Complex With Tryptophan: Synthesis, Structural Characterization, Dft Studies And Biological Assays In Vitro Over Human Tumorigenic Cells.

A new platinum(II) complex with the amino acid L-tryptophan (trp), named Pt-trp, was synthesized and characterized. Elemental, thermogravimetric and ESI-QTOF mass spectrometric analyses led to the composition [Pt(C11H11N2O2)2]⋅6H2O. Infrared spectroscopic data indicate the coordination of trp to Pt(II) through the oxygen of the carboxylate group and also through the nitrogen atom of the amino group. The (13)C CP/MAS NMR spectroscopic data confirm coordination through the oxygen atom of the carboxylate group, while the (15)N CP/MAS NMR data confirm coordination of the nitrogen of the NH2 group to the metal. Density functional theory (DFT) studies were applied to evaluate the cis and trans coordination modes of trp to platinum(II). The trans isomer was shown to be energetically more stable than the cis one. The Pt-trp complex was evaluated as a cytotoxic agent against SK-Mel 103 (human melanoma) and Panc-1 (human pancreatic carcinoma) cell lines. The complex was shown to be cytotoxic over the considered cells.

Espectroscopia de Ressonância Magnética Nuclear de 13C no estudo de rotas biossintéticas de produtos naturais

During the last five decades, as a result of an interaction between natural product chemistry, synthetic organic chemistry, molecular biology and spectroscopy, scientists reached an extraordinary level of comprehension about the natural processes by which living organisms build up complex molecules. In this context, 13C nuclear magnetic resonance spectroscopy, allied with isotopic labeling, played a determinant role. Nowadays, the widespread use of modern NMR techniques allows an even more detailed picture of the biochemical steps by accurate manipulation of the atomic nuclei. This article focuses on the development of such techniques and their impact on biosynthetic studies.

NMR imaging of fluid pathways during drainage of softwood in a pressure membrane chamber

An experiment was implemented to study fluid flow in a pressure media. This procedure successfully combines nuclear magnetic resonance imaging with a pressure membrane chamber in order to visualize the non-wetting and wetting fluid flows with controlled boundary conditions. A specially designed pressure membrane chamber, made of non-magnetic materials and able to withstand 4 MPa, was designed and built for this purpose. These two techniques were applied to the drainage of Douglas fir sapwood. In the study of the longitudinal flow, narrow drainage fingers are formed in the latewood zones. They follow the longitudinal direction of wood and spread throughout the sample length. These fingers then enlarge in the cross-section plane and coalesce until drainage reaches the whole latewood part. At the end of the experiments, when the drainage of liquid water in latewood is completed, just a few sites of percolation appear in earlywood zones. This difference is a result of the wood anatomical structure, where pits, the apertures that allow the sap to flow between wood cells, are more easily aspirated in earlywood than in latewood. (C) 2007 Elsevier Ltd. All rights reserved.

Structural characterization of exopolysaccharides from biofilm of a cariogenic streptococci

Soluble (EPS-SOL), as well as insoluble extracellular polysaccharide (EPS-INSOL), extracted from biofilm of Streptococcus mutans, were analyzed by nuclear magnetic resonance spectroscopy, methylation analysis, and a controlled Smith degradation. EPS-SOL was a branched alpha-glucan containing a (1 -> 6)-and (1 -> 3)-linkages. EPS-INSOL was a branched alpha-glucan with similar linkages, but with a (1 -> 3)-linked main-chain partially substituted at O-6 with Glcp-(1 -> 6)-Glcp-side chains. Biofilm EPS had a distinct chemical structure compared with those synthesized by plankton cells or by purified enzymes from S. mutans, which could indicate different mechanisms for its degradation. (C) 2011 Published by Elsevier Ltd.

Fungal tyrosine betaine, a novel secondary metabolite from conidia of entomopathogenic Metarhizium spp. fungi

Fungi, including the entomopathogenic deuteromycete Metarhizium anisopliae, produce a wide diversity of secondary metabolites that either can be secreted or stored in specific developmental structures, e.g., conidia. Some secondary metabolites, such as pigments, polyols and mycosporines, are associated with pathogenicity and/or fungal tolerance to several stress-inducing environmental factors, including temperature and solar radiation extremes. Extracts of M. anisopliae var. anisopliae (strain ESALQ-1037) conidia were purified by chromatographic procedures and the isolated compounds analyzed by (1)H and (13)C nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. LC-MS analyses were carried out to search for mycosporines (the initial targets), but no compounds of this class were detected. A molecule whose natural occurrence was previously undescribed was identified. It consists of betaine conjugated with tyrosine, and the structure was identified as 2-([1-carboxy-2-(4-hydroxyphenyl)ethyl]amino)-N,N,N-trimethyl-2-oxoethanammonium. mannitol was the predominant compound in the alcoholic conidial extract, but no amino acids other than tyrosine were found to be conjugated with betaine in conidia. The fungal tyrosine betaine was detected also in conidial extracts of three other M. anisopliae var. anisopliae (ARSEF 1095, 5626 and 5749) and three M. anisopliae var. acridum isolates (ARSEF 324, 3391 and 7486), but it was not detected in Aspergillus nidulans conidial extract (ATCC 10074). (C) 2010 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Solution structure of robustoxin, the lethal neurotoxin from the funnel-web spider Atrax robustus

The solution structure of robustoxin, the lethal neurotoxin from the Sydney funnel-web spider Atrax robustus, has been determined from 2D H-1 NMR data, Robustoxin is a polypeptide of 42 residues cross-linked by four disulphide bonds, the connectivities of which were determined from NMR data and trial structure calculations to be 1-15, 8-20, 14-31 and 16-42 (a 1-4/2-6/3-7/5-8 pattern), The structure consists of a small three-stranded, anti-parallel beta-sheet and a series of interlocking gamma-turns at the C-terminus. It also contains a cystine knot, thus placing it in the inhibitor cystine knot motif family of structures, which includes the omega-conotoxins and a number of plant and animal toxins and protease inhibitors. Robustoxin contains three distinct charged patches on its surface, and an extended loop that includes several aromatic and non-polar residues, Both of these structural features may play a role in its binding to the voltage-gated sodium channel. (C) 1997 Federation of European Biochemical Societies.

Carrageenans with complex substitution patterns from red algae of the genus Erythroclonium

Extracellular polysaccharides from three Erythroclonium spp. were shown, by a combination of compositional, linkage analyses, and Fourier transform infrared and C-13-nuclear magnetic resonance spectroscopy, to be highly substituted carrageenans with at least five types of repeating disaccharide units. These are the carrabiose 2,4'-disulfate of iota-carrageenan, carrabiose 2-sulfate of alpha-carrageenan, the 6'-O-methylated counterparts of each of these repeating units, and 4',6'-O-(1-carboxyethylidene)carrabiose 2-sulfate. The polysaccharides also contain significant amounts of unsubstituted, 4-linked galactopyranose and small amounts of 4-linked 3-O-methylgalactopyranose and terminal glycosyl residues. The carrageenan preparations of the three species are similar, differing only in the proportions of some components. (C) 1998 Elsevier Science Ltd.

A pyruvated carrageenan from Australian specimens of the red alga Sarconema filiforme

The carrageenan from two Australian specimens of the red alga Sarconema filiforme was shown by a combination of compositional analyses, linkage analysis, and Fourier transform infrared and C-13 nuclear magnetic resonance spectroscopy to be composed predominantly of a hybrid or mixture of carrabiose 2-sulfate (the repeating unit of alpha-carrageenan), carrabiose 2,4'-disulfate (the repeating unit of iota-carrageenan), and the pyruvated unit 4',6'-O-(1-carboxyethylidene)carrabiose 2-sulfate. (C) 1998 Elsevier Science Ltd. All rights reserved.

A H-1 MRS study of probable Alzheimer's disease and normal aging: Implications for longitudinal monitoring of dementia progression

In order to evaluate the capability of H-1 MRS to monitor longitudinal changes in subjects with probable Alzheimer's disease (AD), the temporal stability of the metabolite measures N-acetylaspartate and N-acetylas-partylglutamate (NA), total Creatine (Cr), myo-Inositol (mI), total Choline (Chol), NA/Cr, mI/Cr, Chol/Cr and NA/mI were investigated in a cohort of normal older adults. Only the metabolite measures NA, mi, Cr, NA/Cr, mI/Cr, and NA/mI were found to be stable after a mean interval of 260 days. Relative and absolute metabolite measures from a cohort of patients with probable AD were subsequently compared with data from a sample of normal older adult control subjects, and correlated with mental status and the degree of atrophy in the localized voxel. Concentrations of NA, NA/Cr, and NA/mI were significantly reduced in the AD group with concomitant significant increases in mi and mI/Cr. There were no differences between the two groups in measures of Cr, Chol, or Chol/Cr. Significant correlations between mental status as measured by the Mini-Mental State Examination and NA/mI, mI/Cr and NA were found. These metabolite measures were also significantly correlated with the extent of atrophy (as measured by CSF and GM composition) in the spectroscopy voxel. (C) 1999 Elsevier Science Inc.