Marcus S. Carrião

Bio: Marcus S. Carrião is an academic researcher from Universidade Federal de Goiás. The author has contributed to research in topics: Magnetic hyperthermia & Ferromagnetic resonance. The author has an hindex of 8, co-authored 10 publications receiving 1029 citations.

Correction: Corrigendum: Effect of magnetic dipolar interactions on nanoparticle heating efficiency: Implications for cancer hyperthermia

Abstract: Nanostructured magnetic systems have many applications, including potential use in cancer therapy deriving from their ability to heat in alternating magnetic fields. In this work we explore the influence of particle chain formation on the normalized heating properties, or specific loss power (SLP) of both low- (spherical) and high- (parallelepiped) anisotropy ferrite-based magnetic fluids. Analysis of ferromagnetic resonance (FMR) data shows that high particle concentrations correlate with increasing chain length producing decreasing SLP. Monte Carlo simulations corroborate the FMR results. We propose a theoretical model describing dipole interactions valid for the linear response regime to explain the observed trends. This model predicts optimum particle sizes for hyperthermia to about 30% smaller than those previously predicted, depending on the nanoparticle parameters and chain size. Also, optimum chain lengths depended on nanoparticle surface-to-surface distance. Our results might have important implications to cancer treatment and could motivate new strategies to optimize magnetic hyperthermia.

Effect of magnetic dipolar interactions on nanoparticle heating efficiency: Implications for cancer hyperthermia

Abstract: Nanostructured magnetic systems have many applications, including potential use in cancer therapy deriving from their ability to heat in alternating magnetic fields. In this work we explore the influence of particle chain formation on the normalized heating properties, or specific loss power (SLP) of both low- (spherical) and high- (parallelepiped) anisotropy ferrite-based magnetic fluids. Analysis of ferromagnetic resonance (FMR) data shows that high particle concentrations correlate with increasing chain length producing decreasing SLP. Monte Carlo simulations corroborate the FMR results. We propose a theoretical model describing dipole interactions valid for the linear response regime to explain the observed trends. This model predicts optimum particle sizes for hyperthermia to about 30% smaller than those previously predicted, depending on the nanoparticle parameters and chain size. Also, optimum chain lengths depended on nanoparticle surface-to-surface distance. Our results might have important implications to cancer treatment and could motivate new strategies to optimize magnetic hyperthermia.

Field dependent transition to the non-linear regime in magnetic hyperthermia experiments: Comparison between maghemite, copper, zinc, nickel and cobalt ferrite nanoparticles of similar sizes

Abstract: Further advances in magnetic hyperthermia might be limited by biological constraints, such as using sufficiently low frequencies and low field amplitudes to inhibit harmful eddy currents inside the patient's body. These incite the need to optimize the heating efficiency of the nanoparticles, referred to as the specific absorption rate (SAR). Among the several properties currently under research, one of particular importance is the transition from the linear to the non-linear regime that takes place as the field amplitude is increased, an aspect where the magnetic anisotropy is expected to play a fundamental role. In this paper we investigate the heating properties of cobalt ferrite and maghemite nanoparticles under the influence of a 500 kHz sinusoidal magnetic field with varying amplitude, up to 134 Oe. The particles were characterized by TEM, XRD, FMR and VSM, from which most relevant morphological, structural and magnetic properties were inferred. Both materials have similar size distributions and satu...

Nanosilver Application in Dental Cements

Abstract: Streptococcus mutans is the microorganism mostly responsible for initiation of tooth decay and also for the progression of an established lesion Silver has been used for its antibacterial properties for many years, in different forms: ionised and elementary forms, as silver zeolites or as nanoparticles The purpose of this study was to evaluate the antibacterial activity of three dental cements modified by nanosilver Three cements were used: Sealapex, RelyX ARC, and Vitrebond The cements were incorporated with 005 mL of silver nanoparticles solution Control groups were prepared without silver Six Petri plates with BHI were inoculated with S mutans using sterile swabs Three cavities were made in each agar plate (total = 18) and filled with the manipulated cements They were incubated at 37∘C for 48 h, and the inhibition halos were measured The paired t-Test was used for statistical analysis (𝑃<005) No inhibition halos were obtained for Sealapex and Rely X, but Vitrebond showed bactericidal activity without silver and enhanced effect with silver incorporation

Characterization techniques for nanoparticles: comparison and complementarity upon studying nanoparticle properties

Abstract: Nanostructures have attracted huge interest as a rapidly growing class of materials for many applications. Several techniques have been used to characterize the size, crystal structure, elemental composition and a variety of other physical properties of nanoparticles. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed. In addition, given that the significance of nanoparticles in basic research and applications is constantly increasing, it is necessary that researchers from separate fields overcome the challenges in the reproducible and reliable characterization of nanomaterials, after their synthesis and further process (e.g. annealing) stages. The principal objective of this review is to summarize the present knowledge on the use, advances, advantages and weaknesses of a large number of experimental techniques that are available for the characterization of nanoparticles. Different characterization techniques are classified according to the concept/group of the technique used, the information they can provide, or the materials that they are destined for. We describe the main characteristics of the techniques and their operation principles and we give various examples of their use, presenting them in a comparative mode, when possible, in relation to the property studied in each case.

Fundamentals and advances in magnetic hyperthermia

Abstract: Nowadays, magnetic hyperthermia constitutes a complementary approach to cancer treatment. The use of magnetic particles as heating mediators, proposed in the 1950s, provides a novel strategy for improving tumor treatment and, consequently, patient's quality of life. This review reports a broad overview about several aspects of magnetic hyperthermia addressing new perspectives and the progress on relevant features such as the ad hoc preparation of magnetic nanoparticles, physical modeling of magnetic heating, methods to determine the heat dissipation power of magnetic colloids including the development of experimental apparatus and the influence of biological matrices on the heating efficiency.

A review on green synthesis of silver nanoparticles and their applications

Abstract: Development of reliable and eco-accommodating methods for the synthesis of nanoparticles is a vital step in the field of nanotechnology. Silver nanoparticles are important because of their exceptional chemical, physical, and biological properties, and hence applications. In the last decade, numerous efforts were made to develop green methods of synthesis to avoid the hazardous byproducts. This review describes the methods of green synthesis for Ag-NPs and their numerous applications. It also describes the comparison of efficient synthesis methods via green routes over physical and chemical methods, which provide strong evidence for the selection of suitable method for the synthesis of Ag-NPs.

Nanosilver particles in medical applications: synthesis, performance, and toxicity.

Abstract: Nanosilver particles (NSPs), are among the most attractive nanomaterials, and have been widely used in a range of biomedical applications, including diagnosis, treatment, drug delivery, medical device coating, and for personal health care With the increasing application of NSPs in medical contexts, it is becoming necessary for a better understanding of the mechanisms of NSPs' biological interactions and their potential toxicity In this review, we first introduce the synthesis routes of NSPs, including physical, chemical, and biological or green synthesis Then the unique physiochemical properties of NSPs, such as antibacterial, antifungal, antiviral, and anti-inflammatory activity, are discussed in detail Further, some recent applications of NSPs in prevention, diagnosis, and treatment in medical fields are described Finally, potential toxicology considerations of NSPs, both in vitro and in vivo, are also addressed

Big Data for Development: A Review of Promises and Challenges

Abstract: Big Data for Development: A Review of Promises and Challenges Martin Hilbert, University of California, Davis; hilbert@ucdavis.edu Author’s version Hilbert, M. (2016). Big Data for Development: A Review of Promises and Challenges. Development Policy Review, 34(1), 135–174. http://doi.org/10.1111/dpr.12142 Abstract The article uses a conceptual framework to review empirical evidence and some 180 articles related to the opportunities and threats of Big Data Analytics for international development. The advent of Big Data delivers the cost-effective prospect to improve decision-making in critical development areas such as health care, economic productivity, and security. At the same time, all the well-known caveats of the Big Data debate, such as privacy concerns and human resource scarcity, are aggravated in developing countries by long-standing structural shortages in the areas of infrastructure, economic resources, and institutions. The result is a new kind of digital divide: a divide in data-based knowledge to inform intelligent decision- making. The article systematically reviews several available policy options to foster the opportunities and minimize the risks. Keywords: Big Data, decision-making, innovation, ICT, digital divide, digital, international development. Acknowledgements: The author thanks International Development Research Centre Canada (IDRC) for commissioning a more extensive study that laid the groundwork for the present article. He is also indebted to Manuel Castells, Nathan Petrovay, Francois Bar, and Peter Monge for food for thought, and to Matthew Smith, Rohan Samarajiva, Sriganesh Lokanathan, and Fernando Perini for helpful comments on draft versions, and thanks the United Nations Economic Commission for Latin America and the Caribbean (UN-CEPAL), where part of the research was undertaken. The views expressed herein are those of the author and do not necessarily reflect the views of the United Nations.