University of the Aegean

About: University of the Aegean is a education organization based out in Mytilene, Greece. It is known for research contribution in the topics: Population & Tourism. The organization has 2818 authors who have published 8100 publications receiving 179275 citations. The organization is also known as: UAEG.

Ultrasound-Assisted Green Extraction of Eggplant Peel (Solanum melongena) Polyphenols Using Aqueous Mixtures of Glycerol and Ethanol: Optimisation and Kinetics

Abstract: Eggplant peels were used to evaluate glycerol and ethanol for their ability to recover polyphenolic antioxidants. The evaluation was based on optimisation by a Box-Behnken experimental design and kinetics. The results showed that extraction with water/ethanol and water/glycerol mixtures, under optimised conditions, afforded virtually equal yield in total polyphenols, which was 13.40 and 13.51 mg caffeic acid equivalents per g dry weight, respectively. The extraction kinetics revealed that diffusion of phenolics in water/glycerol mixtures was slower (0.85 × 10−12 m2 s−1) compared with the one attained with water/ethanol (2.23 × 10−12 m2 s−1), yet the ability of both systems to recover essentially the same levels of total polyphenols was confirmed. The determination of total chlorogenates, total flavonoids and total pigments indicated that water/glycerol might be a more effective solvent system, but controversies were observed with regard to the antiradical activity and reducing power. The analytical polyphenolic profile of both extracts was dominated by chlorogenic acid and no major differences were recorded, a finding indicating that none of the solvent systems displayed selectivity. The results suggested that glycerol may be an ideal candidate for use in eco-friendly extraction processes.

On the determination of non-local symmetries

Abstract: The importance of non-local symmetries of differential equations lies in their manifestation as Lie point symmetries of the equations resulting from reduction of order. The reason for the determination of these symmetries in second-order equations with only one Lie point symmetry is self-evident. However, the disadvantage of non-local symmetries is that no systematic approach to their determination exists. We present such an approach (applicable to differential equations of any order) and apply it to some second-order ordinary differential equations and show that they have a rich occurrence. We also look at possible generalizations of the concept of non-local symmetries.

An overview of body sensor networks in enabling pervasive healthcare and assistive environments

Abstract: The use of sensor networks for healthcare, well-being, and working in extreme environments has long roots in the engineering sector in medicine and biology community. With the growing needs in ubiquitous communications and recent advances in very-low-power wireless technologies, there has been considerable interest in the development and application of wireless networks around humans. With the maturity of wireless sensor networks, body area networks (BANs), and wireless BANs (WBANs), recent efforts in promoting the concept of body sensor networks (BSNs) aim to move beyond sensor connectivity to adopt a system-level approach to address issues related to biosensor design, interfacing, and embodiment, as well as ultra low-power processing / communication, power scavenging, autonomic sensing, data mining, inferencing, and integrated wireless sensor microsystems. As a result, the system architecture based on WBAN and BSN is becoming a widely accepted method of organization for ambulatory and ubiquitous monitoring systems. This review paper presents an up-to-date report of the current research and enabling applications and addresses some of the challenges and implementation issues.

The Finokalia Aerosol Measurement Experiment – 2008 (FAME-08): an overview

Abstract: . A month (4 May to 8 June 2008) of ambient aerosol, air ion and gas phase sampling (Finokalia Aerosol Measurement Experiment 2008, FAME-08) was conducted at Finokalia, on the island of Crete, Greece. The purpose of the study was to characterize the physical and chemical properties of aged aerosol and to investigate new particle formation. Measurements included aerosol and air ion size distributions, size-resolved chemical composition, organic aerosol thermal volatility, water uptake and particle optical properties (light scattering and absorption). Statistical analysis of the aerosol mass concentration variations revealed the absence of diurnal patterns suggesting the lack of strong local sources. Sulfates accounted for approximately half of the particulate matter less than 1 micrometer in diameter (PM1) and organics for 28%. The PM1 organic aerosol fraction was highly oxidized with 80% water soluble. The supermicrometer particles were dominated by crustal components (50%), sea salt (24%) and nitrates (16%). The organic carbon to elemental carbon (OC/EC) ratio correlated with ozone measurements but with a one-day lag. The average OC/EC ratio for the study period was equal to 5.4. For three days air masses from North Africa resulted in a 6-fold increase of particulate matter less than 10 micrometers in diameter (PM10) and a decrease of the OC/EC ratio by a factor of 2. Back trajectory analysis, based on FLEXPART footprint plots, identified five source regions (Athens, Greece, Africa, other continental and marine), each of which influenced the PM1 aerosol composition and properties. Marine air masses had the lowest PM1 concentrations and air masses from the Balkans, Turkey and Eastern Europe the highest.