Fe3o4 Nanoparticles For Magnetic Hyperthermia And Drug Delivery: Synthesis, Characterization And Cellular Studies

In recent years, magnetic nanoparticles (MNPs), especially superparamagnetic Fe3O4nanoparticles, have attracted a great deal of attention because of their potential applications in biomedicine. Among the other applications, Magnetic hyperthermia (MHT), where localized heating is generated by means of relaxation processes in MNPs when subjected to a radio frequency magnetic field, has a great potential as a non-invasive cancer therapy treatment. Specific absorption rate (SAR), which measures the efficiency of heat generation, depends on magnetic properties of the particles such as saturation magnetization (Ms), magnetic anisotropy (K), particle size distribution, magnetic dipolar interactions, and the rheological properties of the target medium.We have investigated MHT in two Fe3O4 ferrofluids prepared by co-precipitation (CP) and hydrothermal (HT) synthesis methods showing similar physical particle size distribution and Ms, but very different SAR ~ 110 W/g and ~ 40 W/g at room temperature. This observed reduction in SAR has been explained by taking the dipolar interactions into account using the so called T* model. Our analysis reveals that HT ferrofluid shows an order of magnitude higher effective dipolar interaction and a wider distribution of magnetic core size of MNPs compared to that of CP ferrofluid. We have studied dextran coated Gd-doped Fe3O4 nanoparticles as a potential candidate in theronostics for multimodal contrast imaging and cancer treatment by hyperthermia. The effect of surfactant on the MHT efficiency and cytotoxicity on human pancreatic cancer cells was explored as well. Though further in vivo study is necessary in the future, these results imply that the dextran coated Fe3O4 dispersion could maintain their high heating capacity in physiological environments while citric acid coating require further surface modification to reduce the non-specific protein adsorption. We have also investigated the traffic, distribution, and cytotoxicity, associated with dextran functionalized FITC conjugated Fe3O4 nanoparticles, and our results demonstrate that there is a time-dependent distribution of these nanoparticles into different cellular compartments. Moreover, a novel conjugation of anti-cancer drug, Doxorubicin (Dox) with a labeling dye (FITC) onto dextran coated Fe3O4 nanoparticles was developed using existing EDC/NHS technique for specific drug targeting. The experiments on this unique drug-dye dual conjugation with human pancreatic cancer cell line (MIA PaCa-2) show that association of Dox onto the surface of nanoparticles enhances its penetration into the cancer cells as compared to the unconjugated drug while releasing Dox into the nucleus of the malignant cells

Sensitivity of cellular oxidative damage to biosynthetic rate and metabolic rate

The relationship between energy expenditure and longevity is a long standing question in aging studies. The empirical results have contradictory effects on the existing theories. A theoretical model and an experimental test of it were presented, revealing the detailed tradeoffs between metabolic rate, biosynthetic rate and cellular damage level. The dissipative mechanisms of oxidative metabolism cause various forms of cellular damages. To counteract the accumulation of damage, organisms have evolved highly efficient maintenance mechanisms. If there is no other energy demand possess, then most of the cellular damage would be repaired, regardless of how metabolic rate varies. However, the repairing mechanisms cost energy. When the energy that could be allocated to repairing is otherwise channeled to biosynthesis during growth, the damage is inevitably accumulated, despite the high repairing efficiency and the variation in biosynthetic rate, and will have a significant impact on the cellular damage level. The model predicts that cellular damage is more sensitive to biosynthetic rate than metabolic rate. To test the prediction, a broad variation in the metabolic and biosynthetic rate was induced in 5th instar hornworms, and assayed the corresponding lipid peroxidation as an indication of cellular damage. The results showed that the metabolic rate had a negligible effect on lipid peroxidation, and the biosynthetic rate had increased the peroxidation. Our study answers a long-standing question regarding the oxidative stress theory of aging: that the treatments that vary the metabolic rate but fail to change the biosynthetic rate have no effects on cellular damage or lifespan, whereas the treatments that change the biosynthetic rate but keep the metabolic rate unchanged will vary animal life span --Abstract, page iv

Low-energy elastic electron interactions with pyrimidine

We present results of measurements and calculations of elastic electron scattering from pyrimidine in the energy range 3–50 eV. Absolute differential and integral elastic cross sections have been measured using a crossed electron-molecule beam spectrometer and the relative flow technique. The measured cross sections are compared with results of calculations using the well-known Schwinger variational technique and an independent-atom model. Agreement between the measured differential cross sections and the results of the Schwinger calculations is good at lower energies but less satisfactory at higher energies where inelastic channels that should be open are kept closed in the calculations

E-marketing in perspective: a three country comparison of business use of the Internet

Presents an inter-country comparison of the business use of the Internet as part of a competitive marketing strategy. Firstly, examines online marketing strategy, reporting that the professed benefits from Internet use are mostly illusory, particularly for the small business sector. Next, describes a survey of 400 businesses in Australia and New Zealand plus a questionnaire survey of 140 business-to-business marketing organizations in the UK and compares the results in terms of the strategic function, marketing communication function, marketing logistics function and relationship management function. Discovers that there are both similarities and differences in the way the three countries use the Internet. Reports that the major difference is in the strategic use of the Internet to gain competitive advantage, improve cost-effectiveness and relationship management, with Australian and New Zealand firms using the Internet to communicate with local firms and maintain relationships at a local level to support sales made through traditional channels.<br /

Influence of Socio-economic and Demographics factors on Households’ Savings in Sri Lanka

The purpose of this paper is to examine the factors influencing saving behavior among households in a developing country. Sri Lanka being a developing country, has recorded a relatively lower households’ &nbsp;saving rate when compared with its peer regional counterparts. The study approximates the socio-economic and demographic factors towards the level of saving of households in Sri Lanka using a quantile regression approach based on the Household Income and Expenditure Survey, conducted by the Department of Census and Statistics of Sri Lanka. Results were obtained by using the stepwise quantile regression technique. The findings of this study conclude that when Sri Lankan households have a higher per-capita income, they tend to have a higher saving level. Moreover, age and marital status have a significant impact on the level of saving in Sri Lankan households. Additionally, poverty and employment status have a significant impact to the level of saving on Sri Lankan households. This research paper bridges empirical gaps in this area of study. Furthermore, this study has been conducted encompassing the entire country rather than limiting it to a district or segment, hence, is comprehensive. As per the generated results gender, income and education levels have shown a significant positive impact towards the level of saving, whilst marital status and poverty have shown a significant negative impact towards the level of saving. It is considered that when the demographic and socio-economic factors are affecting favorably, the level of saving tends to increase and vice versa. Accordingly, findings of the study can provide insights to policymakers to devise policies and incentives to encourage savings behaviour and level of savings among households in Sri Lanka. This is beneficial as coping strategies specially during crises, where dependency of households on government assisted welfare schemes is likely to be less. Keywords: Household Saving Behaviour, Motives of Savings, Barriers to Saving, Quantile Regressio

A three country comparison of internet marketing

This paper provides information on business use of the Internet (Net) and World Wide Web (Web) across three countries viz Australia, New Zealand and the United Kingdom (UK), and explores reasons for observed differences in use. The study reports that UK firms are more likely to use the Internet in relationship management than are Australasian firms. The conclusion drawn is that while there is less sophisticated business use of the Internet by Australasian companies relative to UK companies, this is but one reason for lower household penetration of the Internet and lower online purchasing levels.<br /

Electron scattering from pyrazine: Elastic differential and integral cross sections

We report on new measurements for elastic electron scattering from pyrazine. Absolute differential cross sections (DCSs) at seven discrete energies in the range 3-50 eV, and over the scattered electron angular range 10°-129°, were determined using a crossed electron-molecular beam spectrometer in conjunction with the well-established relative flow technique. Integral elastic cross sections were subsequently derived from those DCS data at each energy. Where possible comparison between the present results and those from sophisticated Schwinger multichannel and R-matrix computations is made, with generally quite good quantitative accord being found. Finally, in order to better study some of the rich resonance structure predicted by theory, results from elastic electron excitation functions are presented.Partial financial support from the Australian Research Council through its Centres of Excellence program is acknowledged

Electron scattering from pyrazine: elastic differential and integral cross-sections

We report on new measurements for elastic electron scattering from pyrazine. Absolute differential cross sections (DCSs) at seven discrete energies in the range 3–50 eV, and over the scattered electron angular range 10°–129°, were determined using a crossed electron-molecular beam spectrometer in conjunction with the well-established relative flow technique. Integral elastic cross sections were subsequently derived from those DCS data at each energy. Where possible comparison between the present results and those from sophisticated Schwinger multichannel and R-matrix computations is made, with generally quite good quantitative accord being found. Finally, in order to better study some of the rich resonance structure predicted by theory, results from elastic electron excitation functions are presented