37 research outputs found

    Physical Properties Of Powdered Roselle-Pineapple Juice - Effects Of Maltodextrin

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    A study was conducted using LabPlant SD-06 Spray Dryer to produce spray-dried rosellepineapple powder. Roselle calyces and pineapples were extracted under optimum condition. Three different maltodextrin DE 10 concentrations (3%, 5% and 10%) were added (w/w) as the encapsulating agent prior to spray drying. Inlet temperatures were varied at 140 oC, 160 oC and 180 oC respectively and the outlet temperature was set at 80 oC. The spray-dried roselle-pineapple powder were analysed for moisture content, dissolution, water activity and hygroscopicity. The results indicated that maldodextrin concentration and inlet temperature had significant effects on the percentage of yield. Extracts with 10% maltodextrin gave the highest percentage of yield and produced less sticky film at the wall of the dryer chamber. At 180 oC, juice with 10% of maltodextrin produced the finest powder. When inlet temperature and the percentage of maltodextrin increased, the moisture content, dissolution and water activity decreased and its hygroscopicity increased

    CTD data profiling to assess the natural hazard of active submarine vent fields: the case of Santorini Island

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    Almost three quarters of known volcanic activity on Earth occurs in underwater locations. The presence of active hydrothermal vent fields in such environments is a potential natural hazard for the environment, the society, and the economy. Despite its importance for risk assessment and risk mitigation, monitoring of the activity is impeded by the remoteness and the extreme conditions of underwater volcanoes. The large difference of population present on Santorini between the winter and summer seasons, all within a partially enclosed system, make the Santorini-Kolumbo volcanic field, an ideal place for detailed exploration. In 2017, GEOMAR in collaboration with the National and Kapodistrian University of Athens (mission: POS-510 ANYDROS), used an Autonomous Underwater Vehicle (AUV) to map the NE–trending Santorini–Kolumbo line, where it also collected CTD data. Here we present the preliminary results from the 15-hour survey held on the 25th March 2017, during the POS-510 expedition targeting the vent field which is located in the North Basin of Santorini Caldera. Detailed CTD 3D profiles have been reconstructed from the raw data of Santorini’s vent field. An anomaly emerges at the depth of 350 m in the Conductivity and Salinity depth profiles, as the CTD sensor is placed directly above the vent sources. Anomalies were evident in the 3D maps reconstructed, showing for the first time a rather weak, but underlying hydrothermal vent activity at various locations. As the present results are the first ones produced from this expedition, further investigation is required incorporating the full dataset. Based on those results, the impact of developing appropriate mechanisms and policies to avoid the associated natural hazard is expected to be immense

    Entropy and Random Walk Trails Water Confinement and Non-Thermal Equilibrium in Photon-Induced Nanocavities

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    Molecules near surfaces are regularly trapped in small cavitations. Molecular confinement, especially water confinement, shows intriguing and unexpected behavior including surface entropy adjustment; nevertheless, observations of entropic variation during molecular confinement are scarce. An experimental assessment of the correlation between surface strain and entropy during molecular confinement in tiny crevices is difficult because strain variances fall in the nanometer scale. In this work, entropic variations during water confinement in 2D nano/micro cavitations were observed. Experimental results and random walk simulations of water molecules inside different size nanocavitations show that the mean escaping time of molecular water from nanocavities largely deviates from the mean collision time of water molecules near surfaces, crafted by 157 nm vacuum ultraviolet laser light on polyacrylamide matrixes. The mean escape time distribution of a few molecules indicates a non-thermal equilibrium state inside the cavity. The time differentiation inside and outside nanocavities reveals an additional state of ordered arrangements between nanocavities and molecular water ensembles of fixed molecular length near the surface. The configured number of microstates correctly counts for the experimental surface entropy deviation during molecular water confinement. The methodology has the potential to identify confined water molecules in nanocavities with life science importance

    Redox active Double Wall Carbon Nanotubes show intrinsic anti-proliferative effects and modulate autophagy in cancer cells

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    In Double-Walled-Carbon-Nanotubes (DWCNTs) the outer shell screens the inner one from the external environment. As a consequence, the electronic properties of the smaller tube are enhanced and DWCNTs have therefore been advocated for a number of uses. In their raw form theymay contain small metallic clusters, left over from the catalytic process, that can give them a redox activity characterized by redox potentials in the range of one hundred millivolts and able to affect biological systems. Indeed, we find that redox active raw-DWCNTs inhibit rat colorectal cancer cell proliferation by blocking cells in the G2 phase through ROS generation by tumor cells. We show that raw-DWCNTs could also modulate autophagy in tumor cells through induction of intracellular acidification. To the best of our knowledge, this is the first time that DWCNTs have been found to inhibit proliferation and modulate autophagy in cancer cells. Our work further supports previous studies that provided promising results on the possibility of future applications of Carbon Nanotubes (CNTs) in nanomedicine

    Designing nanomachines: A theoretical and computational approach

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    Artificial nano-machines operate within environments where the competition of the stochastic and the deterministic part of the motion defines the conditions of their functioning. As their nature counterparts, bio-motors that function mainly inside a cell, man made machines operate far from equilibrium and usually on constant temperature conditions. Given this and taking a Markovian stochastic model as the initial seed, the evolution of the system may be described both in continuous and discrete space, while mean averaged time depended properties can be given as function of the dynamic characteristics of the system, positions and intensities of interaction potentials. Both the dynamic characteristics of a motor as well as their use for designing a molecular motor that shall achieve the desired directional motion are discussed in this review. Copyright \ua9 2010 American Scientific Publishers \ue0 All rights reserved

    Temperature and Conductivity as Indicators of the Morphology and Activity of a Submarine Volcano: Avyssos (Nisyros) in the South Aegean Sea, Greece

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    The morphology and the activity of a submarine caldera, Avyssos, at the northern part of Nisyros volcano in the South Aegean Sea (Greece), has been studied by means of remotely-operated underwater vehicle dives. The recorded time series of temperature and conductivity over the submarine volcano have been analyzed in terms of the generalized moments method. The findings of the mathematical analysis shed light on the volcanic activity, but also on the morphology (shape) of the submarine volcano. The conductivity time series indicates that the volcano is at rest, in agreement with other types of observations. On the other hand, temperature fluctuations, which in general describe a multifractal process, show that the submarine caldera operates as an open system that interacts with its surroundings. This type of analysis can be used as an indicator for the state of activity and the morphological structure (closed or open system) of a submarine volcano

    Explicit propagators for a random walker and unidirectionality on linear chains

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    Explicit propagators are given for a diffusing particle (motor) moving on a linear chain of either infinity or finite length with reflecting ends. Each chain contains a number of thermally accessible barriers and/or potential wells (active sites). All particle interactions with its environment are considered to be short-range and are described by repulsive/attractive delta function potentials. By employing perturbation expansion, closed analytical expressions for the spatio-temporal evolution of the probability density function of the motor are derived, and are valid up to second order with respect to the expansion parameter u, which denotes the strength of interaction between motor and active sites. The mean displacement for two different chains is calculated indicating in both cases that the organization of the motion is done through the interplay of interaction intensities and their positions. © 2012 Elsevier B.V. All rights reserved

    Time fractional diffusion equations and analytical solvable models

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    The anomalous diffusion of a particle that moves in complex environments is analytically studied by means of the time fractional diffusion equation. The influence on the dynamics of a random moving particle caused by a uniform external field is taken into account. We extract analytical solutions in terms either of the Mittag-Leffler functions or of the M- Wright function for the probability distribution, for the velocity autocorrelation function as well as for the mean and the mean square displacement. Discussion of the applicability of the model to real systems is made in order to provide new insight of the medium from the analysis of the motion of a particle embedded in it

    Modeling language evolution: Aromanian, an endangered language in Greece

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    Time evolution of the relative density of speakers of an endangered language, Aromanian, which is spoken by a bilingual community in North-Western Greece, is approached theoretically by means of a two-state model and a three-state model. The same prestige and volatility parameters are used in these two models. Furthermore, a culture parameter and a second exponent are introduced in the three-state model. The parameters of each model are fitted to the current status of Aromanian, on the basis of field evidence collected by us, and the first findings about the risk of the language's extinction are presented. \ua9 2012 Elsevier B.V. All rights reserved
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