Functionalized nanoparticles for AMF-induced gene and drug delivery.

The properties and broad applications of nano-magnetic colloids have generated much interest in recent years. Specially, Fe304 nanoparticles have attracted a great deal of attention since their magnetic properties can be used for hyperthermia treatment or drug targeting. For example, enhanced levels of intracellular gene delivery can be achieved using Fe304 nano-vectors in the presence of an external magnetic field, a process known as \u27magnetofection\u27. The low cytotoxicity, tunable particle size, ease of surface functionalization, and ability to generate thermal energy using an external alternating magnetic field (AMF) are properties have propelled Fe304 research to the forefront of nanoparticle research. The strategy of nanoparticle-mediated, AMF-induced heat generation has been used to effect intracellular hyperthermia. One application of this \u27magnetic hyperthermia\u27 is heat activated local delivery of a therapeutic effector (e.g.; drug or polynucleotide). This thesis describes the development of a magnetic nano-vector for AMF-induced, heat-activated pDNA and small molecule delivery. The use of heat-inducible vectors, such as heat shock protein (hsp) genes, is a promising mode of gene therapy that would restrict gene expression to a local region by focusing a heat stimulus only at a target region. We thus aimed to design an Fe304 nanoparticle-mediated gene transfer vehicle for AMF-induced localized gene expression. We opted to use \u27click\u27 oximation techniques to assemble the magnetic gene transfer vector. Chapter 2 describes the synthesis, characterization, and transfection studies of the oxime ether lipid-based nano-magnetic vectors MLP and dMLP. The synthesis and characterization of a novel series of quaternary ammonium aminooxy reagents (2.1-2.4) is described. These cationic aminooxy compounds were loaded onto nanoparticles for ligation with carbonyl groups and also to impart a net positive charge on the nanoparticle surface. Our studies indicated that the non-toxic magnetoplexes (magnetic nanoparticle + pDNA complex) derived from dMLP deliver pDNA into mammalian cells even without external magnetic assistance. To date, dMLP is the only polymer-free magnetic gene delivery system that can deliver pDNA without any magnetic assistance. Chapter 3 of this thesis outlines the synthesis and characterization of other oxime ether lipids and details studies using derived-lipoplexes. These lipids were evaluated in pDNA and siRNA transfection studies in various mammalian cell lines. This work constitutes the first use of an oxime ether as the linking domain in cationic transfection lipids. These biocompatible oxime ether lipids can be readily assembled by click chemistry through ligation of hydrophobic aldehydes with quaternary ammonium aminooxy salts. Our studies showed that the oxime ether lipids transfected pDNA and siRNA efficiently in MCF -7, H 1792, and in PAR C 10 cells comparable to and in some cases better than commercial transfection lipids. Chapter 4 describes the design and characterization of a nano-magnetic delivery system for AMF-induced drug (doxorubicin) release. In efforts to develop a magnetic formulation free from thermo sensitive materials, such as hydrogels, we synthesized three nanoparticle-based doxorubicin formulations using charge interactions as the key associative force. To do so, we synthesized and characterized a novel cationic oxime ether conjugate at C-13 of doxorubicin. Our investigation indicated that the positive charge of the oxime ether drug conjugate tended to bind better to the negatively charged nanoparticle than did the other formulations prepared in stepwise manner. Our findings show that the nano-magnetic formulations remained essestially inactive at body temperature (37.5 °C) and released a majority of the cargo only when exposed to an external AMF. Our designed magnetic drug delivery platform is the first example of an AMF-inducible system that does not depend on the inclusion of thermo sensitive materials. Finally, we have developed a bioanalytical application of the highly chemoselective oximation chemistry using aminooxy reagent 2.1. Chapter 5 describes a silica microchip containing micropillars coated with cationic aminooxy reagent 2.1. The microchip captures gaseous ketones and aldehydes from exhaled human breath. A brief description of microchip fabricated breath analyzer and breath analysis is described in Chapter 5. Our studies showed that the acetone capture efficiency of the aminooxy-loaded microchip was 98%

Electro-Optic Excitations in van der Waals Materials for Active Nanophotonics

van der Waals materials are emerging due to their unique properties such as atomic thickness, diverse quasiparticle optical resonances, and no requirement for lattice matching. While there is a vast variety of materials, semiconductors hold a special place for opto-electronic and linear/non-linear optical studies. Black phosphorus (BP), a 2D quantum-well with direct bandgap and puckered crystal structure, is a compelling platform for this research direction. In this thesis, we investigate fundamental optical excitations in novel low-dimensional quantum materials to achieve strong light-matter interaction and integrate with nanophotonic motifs for low-footprint, reconfigurable optical technology, focusing primarily on black phosphorus and transition metal dichalcogenides. The thesis begins with the 'thin film limit' of van der Waals materials, between 5 and 20 nm thickness range. Chapters 2 and 3 explore how few-layer black phosphorus hosts interband and intraband optical excitations that can be strongly modified with gate-controlled doping and electric field, displaying epsilon near zero and hyperbolic behavior in the mid and far-infrared. In atomic thickness, strongly bound excitonic quasiparticles dominate the optical response. In Chapter 4, we investigate electrically tunable excitons in tri-layer black phosphorus, demonstrating a reconfigurable birefringent material that, when coupled with a Fabry-Perot cavity, enables the realization of a versatile and broadband polarization modulator. In Chapter 5, we examine the ultimate limit of a monolayer, studying MoTe2 via photoluminescence measurements and first-principles GW+BSE calculations, highlighting the Rydberg series associated with the exciton and its gate-tunability to understand strong electron-exciton interactions. In Chapter 6, we show how such excitons in monolayer black phosphorus can be strongly quantum confined at natural edges of exfoliated flakes, leading to highly temporally coherent emission. This emission is gate-tunable and understood via transmission electron microscopy and first-principles GW+BSE calculations of phosphorene nanoribbons to be originating from atomic reconstructions of the edge coupled with strain and screening effects. Overall, our work highlights the potential of van der Waals materials for various electro-optical excitations and their applications in active nanophotonics. </p

Minimization of Handoff Failure Probability for Next-Generation Wireless Systems

During the past few years, advances in mobile communication theory have enabled the development and deployment of different wireless technologies, complementary to each other. Hence, their integration can realize a unified wireless system that has the best features of the individual networks. Next-Generation Wireless Systems (NGWS) integrate different wireless systems, each of which is optimized for some specific services and coverage area to provide ubiquitous communications to the mobile users. In this paper, we propose to enhance the handoff performance of mobile IP in wireless IP networks by reducing the false handoff probability in the NGWS handoff management protocol. Based on the information of false handoff probability, we analyze its effect on mobile speed and handoff signaling delay.Comment: 16 Page

Malnutrition: food prejudice and preconceptions

Food is responsible for body building, energy yielding, protection and regulation and maintenance of health.&nbsp; Food prejudice and preconceptions can effect on human nutrition. Some people have a lot of preconceived notions or prejudices regarding different foods.&nbsp; People sometimes have preconceived notions about "banana" and "egg," but a banana is a wonderful source of potassium and an antioxidant like vitamin C that support heart health, blood pressure regulation, and the prevention of cancer and asthma. However, some individuals think that eating an egg or a banana in the morning, while travelling, or right before an exam brings ill luck. However, most individuals are unaware of the reasons why a banana is bad for your health in the morning. Some individuals think that if they view it first thing in the morning, their entire day would be terrible or wasted. All this prejudice and preconception directly related to malnutrition. This review paper shows that food prejudice and preconceptions often lead to malnutrition and malnutrition associated disorders. By imparting scientific facts, this article hopes to break down preconceived notions or prejudices about food to prevent malnutrition

Etiology and risk factors of ischemic stroke in Indian-American patients from a hospital-based registry in New Jersey, USA

Background and Objective: The stroke center at the New Jersey Neuroscience Institute is located in Edison township in New Jersey which has one of the largest fractions of Asian immigrants in USA. This study aims to compare risk factors and etiology of ischemic stroke in patients of Indian origin with those of the White-Americans. Methods: Information pertaining to stroke risk factors was prospectively collected between July 2005 to June 2008. The patients underwent a stroke work-up, which included computerized tomograms, magnetic resonance imaging and magnetic resonance angiography of brain, carotid duplex, Holter monitoring and two dimensional echocardiogram. Etiology of ischemic stroke was ascertained using the classification developed for the Trial of Org 10172 in Acute Stroke Treatment (TOAST). Results: The data of 378 patients (mean age = 71±12 years, 54% females, White-Americans=347) with ischemic stroke were collected over 3 years. The 31 Indian patients (mean age = 64±10 years) had a higher proportion of diabetics mellitus (p=0.001) and were signifi cantly younger than the White-Americans. There were signifi cantly lower proportion of persons who smoked (p=0.03) or used alcohol (p=0.03). The commonest cause of ischemic stroke was small vessel occlusive disease, rather than large artery atherosclerosis among the White-Americans (p=0.009). Conclusions: when compared to White-Americans, The Indian-American developed stroke at a younger age, despite a lower rate of alcohol and tobacco use. They have a higher prevalence of diabetes and physical inactivity. The commonest cause of ischemic stroke was small vessel occlusive disease

Functional Foods: Potential Activity For Controlling Heart Disease

In modern communities, functional foods are very much acceptable to health-conscious people. Functional foods are considered healthy foods. Chronic diseases like Heart-related issues develop due to the intake of excessive quantities of fat, refined sugar, salt, and cholesterol-rich foods. However functional foods are involved to facilitate heart distress. Intake of active food ingredients like micronutrients (vitamins and minerals), dietary fibre, antioxidants, and probiotic foods improve cardiovascular disorder therefore upgrading physical and mental well-being. Authors have demonstrated that aged people suffer chronic distress in general therefore it can be prevented by functional foods. functional foods are more relevant than synthetic drugs or pharmaceuticals. So, heart-related issues are torn down by the consumption of functional foods in adequate quantity. Functional foods which have good quantity of bioactive compounds, nutraceutical attributes these are fruits and vegetables, green tea, turmeric, onion, spirulina, soyabean, oats and barley, probiotics and prebiotics, extra virgin olive oil and so on, have capability to mitigate intricate difficulties of cardiovascular disease. Precisely, the motive of this review is the advantageous effect of functional foods in preventing the manifestations of heart disorders around the globe. This review article highlights functional foods' potential activity to control heart disorders

Dephasing effects on coherent exciton-polaritons and the breakdown of the strong coupling regime

International audienceUsing femtosecond pump-probe spectroscopy, we identify excitation-induced dephasing as a major mechanism responsible for the breakdown of the strong coupling between excitons and photons in a semiconductor microcavity. The effects of dephasing are observed on the transmitted probe-pulse spectrum as a density-dependent broadening of the exciton-polariton resonances and the emergence of a third resonance at high excitation density. A striking asymmetry in the energy shift between the upper and the lower polaritons is also evidenced. Using the excitonic Bloch equations, we quantify the respective contributions to the energy shift of many-body effects associated with Coulomb fermion exchange and photon assisted exchange processes and the contribution to collisional broadening

All-dielectric multiple quantum well active metasurfaces

We report a design of an all-dielectric Mie-resonant active metasurface, which exhibits a high reflectance (>45%) and a broad tunable phase shift at an operation wavelength of 1550 nm. The proposed design can be used for the realization of two-dimensional active metasurfaces