Browning development in white wines: dependence on compositional parameters and impact on antioxidant characteristics

Browning is a serious problem in relation to white wine quality and mostly affects the sensory attributes, whereas its impact on the dietary value of wines has never been investigated. Browning, however, is well known to be associated with polyphenol oxidation, and therefore it may be accompanied by changes in the antioxidant capacity. On the basis of this consideration, experimental white wines vinified and stored under identical conditions were subjected to accelerated browning, and efforts were made to distinguish compositional parameters that might be related to the extent of browning development. Further, the consequences of browning on the reducing power and antiradical activity were assessed. It was shown that none of the parameters examined (titratable acidity, pH, total SO₂, total polyphenols and total flavanols) play an important role in browning onset, but SO₂ appeared to exert a statistically significant influence (r²=0.6394, P<0.05) on the percentage change in the antiradical activity. Evidence also suggested that browning development might be prominently associated with decreases in both antiradical activity (r²=0.7891, P<0.01) and reducing power (r²=0.6925, P<0.05).     

Optimized in-phase and opposed-phase MR imaging for accurate detection of small fat or water fractions: theoretical considerations and experimental application in emulsions

Object  

To optimize strategies and measurement parameters for quantification of small fat and water fractions (<10%) in mixtures of both components by 4-point in-phase and opposed-phase gradient-echo imaging and to compare theoretical results with in-vitro experiments using emulsions.     

Beyond platinum: synthesis,characterization, and in vitro toxicity of Cu(II)-releasing polymer nanoparticles for potential use as a drug delivery vector

The field of drug delivery focuses primarily on delivering small organic molecules or DNA/RNA as therapeutics and has largely ignored the potential for delivering catalytically active transition metal ions and complexes. The delivery of a variety of transition metals has potential for inducing apoptosis in targeted cells. The chief aims of this work were the development of a suitable delivery vector for a prototypical transition metal, Cu²⁺, and demonstration of the ability to impact cancer cell viability via exposure to such a Cu-loaded vector. Carboxylate-functionalized nanoparticles were synthesized by free radical polymerization and were subsequently loaded with Cu²⁺ via binding to particle-bound carboxylate functional groups. Cu loading and release were characterized via ICP MS, EDX, XPS, and elemental analysis. Results demonstrated that Cu could be loaded in high weight percent (up to 16 wt.%) and that Cu was released from the particles in a pH-dependent manner. Metal release was a function of both pH and the presence of competing ligands. The toxicity of the particles was measured in HeLa cells where reductions in cell viability greater than 95% were observed at high Cu loading. The combined pH sensitivity and significant toxicity make this copper delivery vector an excellent candidate for the targeted killing of disease cells when combined with an effective cellular targeting strategy.     

Effects of Drying and Extraction Methods on the Quality and Antioxidant Activity of Sea Buckthorn (Hippophae rhamnoides) Berries and Leaves

Sea buckthorn is a promising source of bioactive compounds. However, there is limited information on the effect of post harvest drying and extraction of sea buckthorn on its antioxidant capacity. The effect of freeze, air, and solar dryingon the extraction yield of sea buckthorn berries and leaves was evaluated with respect to their bioactive content. Sequential extraction with solvents of different polarity and solvent-free microwave-assisted extraction were applied. Freeze-drying has better performance in the berries’ extracts, while air-drying has better performance in the leaves’ extracts. All data were analyzed by Multi Factor Analysis of Variance (ANOVA) and Duncan's post-hoc tests at a level of α = .05. Although the extraction yield in the sequential extraction of sea buckthorn berries is significantly better, the leaves’ extracts exhibit superior radical scavenging ability. Accelerated solar drying appears to preserve sea buckthorn leaves without degrading their antioxidant content. The components responsible for the high antioxidant activity of leaves’ extracts were found to be several flavonoids and polyphenols. The extract obtained by the microwave extraction of fresh berries exhibits moderate antioxidant activity compared to the polar extracts of freeze-dried berries.     

Distributed Online Algorithms for the Agent Migration Problem in WSNs

The mobile agent paradigm has been adopted by several systems in the area of wireless sensor networks as it enables a flexible distribution and placement of application components on nodes, at runtime. Most agent placement and migration algorithms proposed in the literature, assume that the communication rates between agents remain stable for a sufficiently long time to amortize the migration costs. Then, the problem is that frequent changes in the application-level communication may lead to several non-beneficial agent migrations, which may actually increase the total network cost, instead of decreasing it. To tackle this problem, we propose two distributed algorithms that take migration decisions in an online fashion, trying to deal with fluctuations in agent communication. The first algorithm is more of theoretical value, as it assumes infinite storage to keep information about the message exchange history of agents, while the second algorithm is a refined version that works with finite storage and limited information. We describe these algorithms in detail, and provide proofs for their competitive ratio vs. an optimal oracle. In addition, we evaluate the performance of the proposed algorithms for different parameter settings through a series of simulated experiments, also comparing their results with those achieved by an optimal static placement that is computed with full (a posteriori) knowledge of the execution scenarios. Our theoretical and experimental results are a strong indication for the robustness and effectiveness of the proposed algorithms.     

Anchor‐free distance estimation: A new approach to distance estimation for multihop ad hoc wireless networks

In ad hoc wireless networks, devices that normally cannot directly communicate route their messages through intermediate nodes. The number of those nodes is called hop count, a useful metric in estimating the distance between 2 nodes. Current methods usually depend on special nodes, called anchors, that need accurate localization information, in order to calculate an estimate for the average distance traversed per hop. The drawback of this approach is that anchor nodes increase the overall cost and complexity of the system. To address this problem, this letter proposes a novel, anchor node–free algorithm that can achieve a useful estimate for actual distance between 2 nodes, by analytically finding an estimate for the average maximum distance traveled per hop and multiplying with the hop count. The only requirement is the a priori knowledge of the networks' node density and the node range. The performance of our method is compared with a recent anchor node–based method and is shown to yield similar location estimation accuracy, despite the fact that it does not use anchor nodes.     

Shape Connectivity: Multiscale Analysis and Application to Generalized Granulometries

This paper develops a multiscale connectivity theory for shapes based on the axiomatic definition of new generalized connectivity measures, which are obtained using morphology-based nonlinear scale-space operators. The concept of connectivity-tree for hierarchical image representation is introduced and used to define generalized connected morphological operators. This theoretical framework is then applied to establish a class of generalized granulometries, implemented at a particular problem concerning soilsection image analysis and evaluation of morphological properties such as size distributions. Comparative results demonstrate the power and versatility of the proposed methodology with respect to the application of typical connected operators (such as reconstruction openings). This multiscale connectivity analysis framework aims at a more reliable evaluation of shape/size information within complex images, with particular applications to generalized granulometries, connected operators, and segmentation.     

Temporal course of perfusion in human masseter muscle during isometric contraction assessed by arterial spin labeling at 3T

Object  

Examination of blood perfusion in the masseter muscle in the course of repetitive isometric contraction by arterial spin-labeling (ASL) MR imaging and additional T2 relaxation time measurements during and after masseter muscle activation.