Estudio experimental de la extracción de carragenano a partir del alga Iridaea laminarioides

El objetivo de este trabajo fue hacer un estudio de factibilidad técnica de un proceso de extracción de carragenano a partir del alga roja Iridaea laminarioides, considerando que la recolección nacional de algas productoras de este polisacárido bordea las 3.000 Ton/año. Se estableció la influencia que tienen sobre el rendimiento y la calidad del producto obtenido, las variables siguientes: tiempo de extracción, relación volumen de solvente de extracción a masa de alga seca, volumen del agente precipitante, tiempo y velocidad de centrifugación, decoloración, etc. El proceso estudiado proporciona un producto blanco, de viscosidad promedio igual a 50 cp para soluciones al 1% en peso a 25°C y que forma geles fuertes cuando se lo trata con hidróxido de potasio. El rendimiento de producto es 70% y corresponde aproximadamente al 400 /o de la masa inicial de alga seca (19% humedad base seca)

The COMPLEX reference framework for HW/SW co-design and power management supporting platform-based design-space exploration

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Magnetic Nanoparticles for Power Absorption: optimizing size, shape and magnetic properties

We present a study on the magnetic properties of naked and silica-coated Fe3O4 nanoparticles with sizes between 5 and 110 nm. Their efficiency as heating agents was assessed through specific power absorption (SPA) measurements as a function of particle size and shape. The results show a strong dependence of the SPA with the particle size, with a maximum around 30 nm, as expected for a Neel relaxation mechanism in single-domain particles. The SiO2 shell thickness was found to play an important role in the SPA mechanism by hindering the heat outflow, thus decreasing the heating efficiency. It is concluded that a compromise between good heating efficiency and surface functionality for biomedical purposes can be attained by making the SiO2 functional coating as thin as possible.Comment: 15 pages, 7 figures, 2 table

CONTREX: Design of embedded mixed-criticality CONTRol systems under consideration of EXtra-functional properties

The increasing processing power of today’s HW/SW platforms leads to the integration of more and more functions in a single device. Additional design challenges arise when these functions share computing resources and belong to different criticality levels. The paper presents the CONTREX European project and its preliminary results. CONTREX complements current activities in the area of predictable computing platforms and segregation mechanisms with techniques to consider the extra-functional properties, i.e., timing constraints, power, and temperature. CONTREX enables energy efficient and cost aware design through analysis and optimization of these properties with regard to application demands at different criticality levels

Nanoflowers Versus Magnetosomes Comparison Between Two Promising Candidates for Magnetic Hyperthermia Therapy

Magnetic Fluid Hyperthermia mediated by iron oxide nanoparticles is one of the most promising therapies for cancer treatment. Among the different candidates, magnetite and maghemite nanoparticles have revealed to be some of the most promising candidates due to both their performance and their biocompatibility. Nonetheless, up to date, the literature comparing the heating efficiency of magnetite and maghemite nanoparticles of similar size is scarce. To fill this gap, here we provide a comparison between commercial Synomag Nanoflowers pure maghemite and bacterial magnetosomes pure magnetite synthesized by the magnetotactic bacterium Magnetospirillum gryphiswaldense of amp; 10216;D amp; 10217; amp; 8776; 40 45 nm. Both types of nanoparticles exhibit a high degree of crystallinity and an excellent degree of chemical purity and stability. The structural and magnetic properties in both nanoparticle ensembles have been studied by means of X Ray Diffraction, Transmission Electron Microscopy, X Ray Absorption Spectroscopy, and SQUID magnetometry. The heating efficiency has been analyzed in both systems using AC magnetometry at several field amplitudes 0 88 mT and frequencies 130, 300, and 530 kH

Room-temperature preparation and characterization of poly (ethylene glycol)-coated silica nanoparticles for biomedical applications

Monodisperse, spherical, polyethylene glycol (PEG)–coated silica nanoparticles have been prepared at room temperature and characterized for the purpose of biomedical applications. The particles were synthesized by the hydrolysis of tetramethyl orthosilicate (TMOS) in alcohol media under catalysis by ammonia, and their size can range from about 50–350 nm in diameter. We studied the particle size and size distribution using a scanning electron microscope (SEM) and an asymmetric field-flow fractionation (AFFF) multiangle static light-scattering instrument. The chemical and/or physical binding of PEG to the silica nanoparticles was studied by infrared spectroscopy, and the weight percentage of PEG attached to the particles was quantified. The PEG-coated silica nanoparticles showed enhanced colloidal stability when redispersed into aqueous solutions from the dried state as a result of the steric stabilization function of the PEG polymer grafted on the surface of particles. A nonspecific protein-binding test was also carried out to show that the PEG coating can help reduce the protein adsorption onto the surface of the particles, relating to the biocompatibility of these PEG-coated particles. Also, the inclusion of magnetic nanoparticles into the silica particles was shown as an example of the possible applications of PEG-coated silica particles. These silica nanoparticles, as a matrix for encapsulation of certain reagents, have potential for applications to in vivo diagnosis, analysis, and measurements inside intact biologic systems. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 870–879, 2003Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34427/1/10057_ftp.pd

Outer space security

This chapter explains how, since the dawn of the space age, security has been a driving force in the development of technical capabilities in outer space. Over the last sixty years, the development of space-related technology has been inextricably linked to military capability—both real and perceived. Today, space is more accessible and depended upon than ever envisaged. The continuing development and reliance on commercial and military space technology challenges the core principle of the ‘peaceful purposes’ doctrine that underpins the current international legal regulation of outer space. The chapter explores the development of activities in outer space, the regulation of national and global space security, and the practical capabilities of leading spacefaring nations. It also highlights some of the critical issues that impact upon security-related concerns for States when it comes to the regulation of armed conflict in outer space. Ultimately, the use of outer space for military purposes gives rise to difficult international law issues relating to the use of force. What is not straightforward is precisely how various aspects of these activities are to be regulated at the international level should they transcend outer space and result in armed conflict

Critical issues in the regulation of armed conflict in outer space

The development of technology to enhance the exploration and use of outer space has continued at a rapid rate ever since the space age began in 1957. Most military leaders regard space-related technology as an integral element of their strategic battle platfom and state security. This reflects the changing technological nature of armed conflict, which challenges many aspects of international law, including the regulation of warfare. The continuing development of commercial and military space technology challenges the core principle of the 'peaceful purposes' doctrine that underpins the international regulation of outer space. This chapter explores the development of activities in outer space, the regulation of space security and the application of the United Nations (UN) space treaties. With a focus on the laws of war to the use of outer space during armed conflict, it looks at their practical application in the Asia-Pacific region, and offers some reflections as to what is required to properly address the issue