Magnetic Nanoparticles as MRI Contrast Agents

Magnetic Resonance Imaging (MRI) is a non-invasive imaging modality that offers both anatomical and functional information. Intrinsic longitudinal and transverse relaxation times (T1 and T2, respectively) provide tools to manipulate image contrast. Additional control is yielded when paramagnetic and magnetic particulate materials are used as contrast materials. Superparamagnetic particles are mostly synthesized from iron oxide and are usually coated with polymers and functional particles to offer multifunctional biomedical applications. The latter include not only MRI but also cancer treatment through drug delivery and hyperthermia. This Chapter reviews the fundamental dipole–dipole diamagnetic proton relaxation mechanism dominant in water followed by a brief description of the use of gadolinium complexes as MRI contrast agent. Finally, a description of the important chemical and physical properties of magnetic nanoparticle (MNP) that define their use as MRI relaxation enhancing agents especially for T2. The main governing models are described for the different motional regimes with few simulation results demonstrating the applicability of the given equations

Multifunctional Nanoparticles for Imaging Guided Interventions

We describe multifunctional magnetic nanoparticles (MNPs) encapsulated in thermosensitive, drug-bearing shells and delivered to the tumor site by genetically modified and non-pathogenic strains of bacteria with known affinity to tumors for an effective and minimally invasive protocol for tumor management. The magnetic nanoparticles also serve as a non-invasive imaging contrast agent, heating agent as well as thermometry monitoring agents. We have shown an efficient tumor management on a mouse model utilizing the MNPs. Our studies showed that these novel MNPs significantly reduce the progress of tumor and prolong the animal life and function as an imaging contrast to visually monitor the tumor treatment and evolution

The Role of Marketing Information System (MkIS) to Improve Performance in the Banking Sector of Jordan

The banking sector has always been high information intensive over the years. This has brought the use of Information technology (IT) as a necessity for data storage, modification and retrieval. Information systems (IS) use the provided infrastructure of IT to leverage advantages of IT and to solve many issues that relates to information acquisition. To these end most financial institutions has been using different types of information systems to gain competitive advantage. One of such system is the Marketing information system (MkIS). The purpose of this study is to explore the role of MkIS in the performance of banking sector in Jordan, an emerging modern Arab economy in the Middle East. The present study modifies the technology acceptance model and the organization effectiveness (organization theory) and applies it to usage of MkIS in the Jordanian banks. With the use of MkIS, banks can make notable savings, increase their customer base, increase sales growth and effectively acquire market and customer information. The availability of this information will assist the banks to improve customer service and invariable win the trust of customers and increase customers' patronage. Quite a number of the banks in Jordan make use of information system. But there is no empirical study yet on the use of MkIS in Jordan, neither are there literatures on the role to which MkIS to the performance of the banks. Therefore, a combination of TAM model and organization effectiveness models were used to investigate the influence of MkIS on bank performance. The result of this study which stands as contribution, as it was revealed that there are positive relations to bank performance as hypothesized. The positive association between combination among all independent variables (ease of use, usefulness, attitude, market procedural improvement, employee support, customer knowledge and market responsiveness)were supported

De Vega annuloplasty versus ring annuloplasty for repair of functional tricuspid regurgitation

Background: Tricuspid insufficiency (TI) is a functional insufficiency in most of the cases and associated with the dilatation of the annulus and remolding. Pulmonary hypertension and right ventricular volume overload due to chronic aortic or / and mitral valve disease in most of the time causes the functional tricuspid insufficiency. Despite the different techniques used to repair the tricuspid valve, the recurrent TR is still occurring in 20- 30 % of the patients and the development of late TR is an important complication of left heart surgery. Our study aims to compare the long-term outcome of ring annuloplasty with De Vega annnuloplasty in patients with secondary tricuspid regurgitation (TR).Methods: A retrospective study of 320 patients who underwent tricuspid valve repair surgery for secondary tricuspid regurgitation from January 2002 to December 2010 at Queen Alia Heart Institute (QAHI). Patients were divided into two groups, in group (1) (n=180) patients had an annuloplasty ring. Group (2) (n=140) patients had De Vega procedure (no ring). The procedures were performed in association with mitral valve surgery in 78% of patients, aortic valve surgery in 15% and combined aortic and mitral valve surgery in 7% of patients. TR grade, NYHA functional class and Pulmonary artery pressure were nearly similar and no significant preoperative difference between the two groups.Results: Echocardiographic and clinical follow up were done for all patients. The duration of procedure for both De Vega and ring annuloplasty were nearly similar. The overall survival in ring group at 5year was 83.9% versus 77.9% in De Vega group. Freedom from residual and recurrent TR, event free survival and long-term survival were significantly better in the ring group and also the tricuspid valve reoperation were less in the ring group.Conclusions: The implantation of annuloplasty ring results in lower incidence of residual or recurrent of tricuspid regurgitation, improved the event-free survival and long-term survival when compared with the sewing techniques such as De Vega

Engineering of nickel, cobalt oxides and nickel/cobalt binary oxides by electrodeposition and application as binder free electrodes in supercapacitors

Cobalt oxide, nickel oxide and cobalt/nickel binary oxides were synthesised by electrodeposition. To fine tune composition of CoNi alloys, growth parameters including voltage, electrolyte pH/concentration and deposition time were varied. These produced nanomaterials were used as binder free electrodes in supercapacitor cells and tested using three electrode setup in 2 MKOH aqueous electrolyte. Cyclic voltammetry and galvanostatic charge/discharge were used at different scan rates (5–100 mV/s) and current densities (1–10 A/g) respectively to investigate the capacitive behaviour and measure the capacitance of active material. Electrochemical impedance spectroscopy was used to analyse the resistive/conductive behaviours of these electrodes in frequency range of 100 kHz to 0.01 Hz at applied voltage of 10 mV. Binary oxide electrode displayed superior electrochemical performance with the specific capacitance of 176 F/g at current density of 1 A/g. This hybrid electrode also displayed capacitance retention of over 83% after 5000 charge/discharge cycles. Cell displayed low solution resistance of 0.35 Ω along with good conductivity. The proposed facile approach to synthesise binder free blended metal electrodes can result in enhanced redox activity of pseudocapacitive materials. Consequently, fine tuning of these materials by controlling the cobalt and nickel contents can assist in broadening their applications in electrochemical energy storage in general and in supercapacitors in particular

Evaluation of Antiproliferative Properties of CoMnZn-Fe₂O₄ Ferrite Nanoparticles in Colorectal Cancer Cells

The PEG-coated ferrite nanoparticles Co0.2Mn0.6Zn0.2Fe2O4 (X1), Co0.4Mn0.4Zn0.2Fe2O4 (X2), and Co0.6Mn0.2Zn0.2Fe2O4 (X3) were synthesized by the coprecipitation method. The nanoparticles were characterized by XRD, Raman, VSM, XPS, and TEM. The magnetic hyperthermia efficiency (MH) was determined for PEG-coated nanoparticles using an alternating magnetic field (AMF). X2 nanoparticles displayed the highest saturation magnetization and specific absorption rate (SAR) value of 245.2 W/g for 2 mg/mL in a water medium. Based on these properties, X2 nanoparticles were further evaluated for antiproliferative activity against HCT116 cells at an AMF of 495.25 kHz frequency and 350 G strength, using MTT, colony formation, wound healing assays, and flow cytometry analysis for determining the cell viability, clonogenic property, cell migration ability, and cell death of HCT116 cells upon AMF treatment in HCT116 cells, respectively. We observed a significant inhibition of cell viability (2% for untreated control vs. 50% for AMF), colony-forming ability (530 cells/colony for untreated control vs. 220 cells/colony for AMF), abrogation of cell migration (100% wound closure for untreated control vs. 5% wound closure for AMF), and induction of apoptosis-mediated cell death (7.5% for untreated control vs. 24.7% for AMF) of HCT116 cells with respect to untreated control cells after AMF treatment. Collectively, these results demonstrated that the PEG-coated (CoMnZn-Fe2O4) mixed ferrite nanoparticles upon treatment with AMF induced a significant antiproliferative effect on HCT116 cells compared with the untreated cells, indicating the promising antiproliferative potential of the Co0.4Mn0.4Zn0.2Fe2O4 nanoparticles for targeting colorectal cancer cells. Additionally, these results provide appealing evidence that ferrite-based nanoparticles using MH could act as potential anticancer agents and need further evaluation in preclinical models in future studies against colorectal and other cancers.</p

A review of power electronic devices for heavy goods vehicles electrification : performance and reliability

This review explores the performance and reliability of power semiconductor devices required to enable the electrification of heavy goods vehicles (HGVs). HGV electrification can be implemented using (i) batteries charged with ultra-rapid DC charging (350 kW and above); (ii) road electrification with overhead catenaries supplying power through a pantograph to the HGV powertrain; (iii) hydrogen supplying power to the powertrain through a fuel cell; (iv) any combination of the first three technologies. At the heart of the HGV powertrain is the power converter implemented through power semiconductor devices. Given that the HGV powertrain is rated typically between 500 kW and 1 MW, power devices with voltage ratings between 650 V and 1200 V are required for the off-board/on-board charger’s rectifier and DC-DC converter as well as the powertrain DC-AC traction inverter. The power devices available for HGV electrification at 650 V and 1.2 kV levels are SiC planar MOSFETs, SiC Trench MOSFETs, silicon super-junction MOSFETs, SiC Cascode JFETs, GaN HEMTs, GaN Cascode HEMTs and silicon IGBTs. The MOSFETs can be implemented with anti-parallel SiC Schottky diodes or can rely on their body diodes for third quadrant operation. This review examines the various power semiconductor technologies in terms of losses, electrothermal ruggedness under short circuits, avalanche ruggedness, body diode and conduction performance

Reduction of T2 Relaxation Rates due to Large Volume Fractions of Magnetic Nanoparticles for All Motional Regimes

The effect of high volume fraction of magnetic nanoparticles (MNP) on Magnetic Resonance Imaging (MRI) transverse relaxation rates (R2 = 1/T2 and R2* = 1/T2*) is investigated using Monte Carlo (MC) simulations. Theoretical models assume that particles occupy a small volume fraction of the sample space. Results presented in this work show that models based on both motional averaged (MAR) and static dephasing (SDR) regimes respectively underestimate and overestimate relaxation rates at large volume fractions. Furthermore, both R2* and R2* become echo-time dependent. This suggests that diffusion is involved with larger echo-times producing smaller relaxation rates due to better averaging of the magnetic field gradients. Findings emphasize the need for the models to be modified to take account of high particle concentration especially important for application involving clustering and trapping of nanoparticles inside cells. This is important in order to improve the design process of MNP Contrast Agents