Mind the gap—deficits in our knowledge of aspects impacting the bioavailability of phytochemicals and their metabolites—a position paper focusing on carotenoids and polyphenols

Various secondary plant metabolites or phytochemicals, including polyphenols and carotenoids, have been associated with a variety of health benefits, such as reduced incidence of type 2 diabetes, cardiovascular diseases, and several types of cancer, most likely due to their involvement in ameliorating inflammation and oxidative stress. However, discrepancies exist between their putative effects when comparing observational and intervention studies, especially when using pure compounds. These discrepancies may in part be explained by differences in intake levels and their bioavailability. Prior to exerting their bioactivity, these compounds must be made bioavailable, and considerable differences may arise due to their matrix release, changes during digestion, uptake, metabolism, and biodistribution, even before considering dose‐ and host‐related factors. Though many insights have been gained on factors affecting secondary plant metabolite bioavailability, many gaps still exist in our knowledge. In this position paper, we highlight several major gaps in our understanding of phytochemical bioavailability, including effects of food processing, changes during digestion, involvement of cellular transporters in influx/efflux through the gastrointestinal epithelium, changes during colonic fermentation, and their phase I and phase II metabolism following absorption.     

Mechanochemical Treatment of CaC03 for Reducing Hyprophylicity

The article discusses the modification of CaCO₃ hydrophylicity by mechanochemical methods, in view of its compatibilization with hydrophobic polymeric matrices. The observation was made that by ultrahigh-speed stirring of the solutions of polybutadiene and acrylic acid—in which CaCO₃ powder has been suspended—as well as by vibratory milling of CaCO₃ in the presence of isoprene, modifications in the hydrophylicity of the anorganic particles occur. The treatment's efficiency depends on two process parameters: duration and monomer/charge ratio.     

Proportional Service Differentiation in Wireless LANs Using Spacing-based Channel Occupancy Regulation

In this paper, we propose Spacing-based Channel Occupancy Regulation (SCORE) MAC protocol for wireless LANs that provides proportional service differentiation in terms of normalized throughput. As shown by our system model and simulation study, SCORE provides consistent, scalable and adjustable proportional differentiation for any network size, any service class distribution, any node data rate and any packet size. Compared to state-of-the-art prioritized service differentiation schemes like Enhanced Distributed Coordination Function (EDCF), SCORE can quantitatively control the channel sharing between different service classes. Moreover, SCORE obtains significant performance improvements in terms of higher network throughput, higher transmission efficiency, lower medium access delay and lower delay jitter. Dr. Qi Xue is now a senior systems engineer with Qualcomm Inc. since Feb. 2005. Qi Xue is currently a Ph.D. candidate in the department of Electrical and Computer Engineering, University of Massachusetts at Amherst. He received his M.S. degree in Electrical and Information Engineering from Huazhong University of Science and Technology, China, in 2000. His research interests include protocol design and performance analysis in wireless networks. Weibo Gong received his Ph.D degree from Harvard University in 1987, and have been with the Dept. of Electrical and Computer Engineering, University of Massachusetts, Amherst since then. He is also an adjunct professor in the Dept. of Computer Science at the same campus. His major research interests include control and systems methods in communication networks, network security, and network modeling and analysis. He is a receipient of the IEEE Transactions on Automatic Control’s George Axelby Outstanding paper award, an IEEE Fellow, and the Program Committee Chair for the 43rd IEEE Conference on Decision and Control. Aura Ganz received her B.Sc, M.Sc and Ph.D degrees in Computer Science from the Technion in Israel. She is currently an associate professor and Director of the Multimedia Networks Laboratory at the ECE Department, University of Massachusetts at Amherst. She has experience in topics related to all strata of networking technology, from work related to topics in the network infrastructure development to advanced user-space application development for mobile clients. The research results are validated by a combination of analytical, simulation and prototyping tools. She has published a book “Multimedia Wireless Networks: Technologies, Standards and QoS” (Prentice Hall) and authored over one hundred and fifty peer reviewed publications. Dr. Ganz is a senior member of IEEE     

Educational Innovations in Multimedia Systems*

Multimedia systems have emerged as one of the fastest growing segments of computing systems and thus need to be well integrated into a computer engineering curriculum. Fortunately the teaching and learning of multimedia systems can be aided with novel instructional techniques based on multimedia. The Multimedia Curriculum project at the University of Massachusetts Amherst is developing a unified set of instructional materials on the engineering techniques used in the design and test of hardware, software and networks for multimedia. This large project includes three facets: 1) multimedia instructional modules using web‐linked Digital Video Disks, 2) multimedia communication utilities to facilitate student interaction, and 3) multimedia component design projects. In this paper, we explain our approach to using multimedia as both content and instructional technology and briefly present preliminary results in each of the three facets.     

2-Cyano-2-butylazoformamidoethyl 4-t-butylazo-4-cyanopentanoate synthesis and its behaviour in methyl methacrylate polymerization

Synopsis In the present paper the synthesis of a new bis-azo initiator, 2-cyano-2-butylazo-formamidoethyl 4-t-butylazo-4-cyanopentanoate, is reported. The structures of the intermediates and of the initiator were confirmed by the IR and ¹H-NMR spectral measurements. The polymerization of methyl methacrylate (MMA) in the presence of this initiator was studied and the conversion-time dependence followed with different concentrations of the initiator and of the monomer.     

A preliminary macroinvertebrate Index of Biotic Integrity for bioassessment of the Kipkaren and Sosiani Rivers,Nzoia River basin,Kenya

Management efforts for the Lake Victoria Basin have been hampered by a lack of clear standards against which to judge the degree of environmental degradation, highlighting the need for a multi‐metric approach for this purpose. Indeed, management priorities for the Lake Victoria catchment must be based on reliable assessments of the biological integrity of the inflowing rivers that can potentially influence the ecological functioning of the lake. Accordingly, macroinvertebrate metrics were evaluated for their responsiveness to human impacts, utilizing Pearson’s correlations with physico‐chemical parameters. The resultant 9 metrics that provided the best discrimination between physico‐chemical samples, using the separation power of Mann–Whitney U and Kolmogorov–Smirnov tests (P < 0.05) from the 21 sampling sites utilized in this study were the: (i) abundances of Ephemeroptera, Plecoptera and Trichoptera; (ii) relative abundances of Diptera; (iii) Ephemeroptera, Plecoptera and Trichoptera:Diptera ratio; (iv) Oligochaeta, Mollusca, Hemiptera, Odonata and the proportions of tolerance taxa; (v) dominant taxa; and (vi) the relative proportions of invertebrates that fall into the gatherer and predator feeding groups, based on the variability they exhibited across the sampling sites. Using the inter‐quartile ranges to establish the scoring criteria, the index was able to delineate impacted from less‐impacted sites along the rivers, providing preliminary evidence of responses to changes in the ecosystem integrity exhibited by resident macroinvertebrate assemblages in both rivers.     

QoS Routing for Mesh-Based Wireless LANs

Wireless LANs with their increased data rate become an attractive technology for connecting mobile users to the Internet. Efficient deployment of wireless LANs will require the ability to extend the wireless LANs coverage without the need to deploy a very large number of access points. Mesh-based wireless LANs are an attractive solution to this problem. These networks extend wireless LAN coverage by using each node in the network as a router, resulting in a multihop topology. In this paper we introduce a novel routing algorithm, wireless mesh routing (WMR), that provides quality-of-service (QoS) support and accounts for the characteristics of both infrastructure-based wireless LANs and ad hoc networks. The algorithm is validated using the OPNET modeler. The simulation results show that the mesh network using WMR protocol can provide QoS support and react dynamically to the network status changes with low control overheads. Using the proposed software architecture the proposed routing protocol can be implemented with any MAC protocol, resulting in easy implementation in existing wireless nodes.     

Accessibility and Network Structures in the German Commuting

A great deal of attention has recently been paid to the analysis of the structure and evolution of (complex) networks, starting from pioneering contributions in the physical and social sciences—and more recently in the regional and transportation sciences—mainly concerning the relevance of highly connected nodes (hubs). The presence of hubs identifies a network as Scale-Free (SF), because of its intrinsic characteristic of exhibiting power-law distributions in its connectivity structure, and thus highly heterogeneous patterns. The focus of this paper is to explore the homogeneous vs. heterogeneous characteristics of the German commuting network, by focusing on the role of accessibility. The concept of accessibility has a long tradition in the transport economics literature, starting with the fundamental works by Hansen in the 1950’s and later on by Weibull in the 1980’s. These authors defined accessibility as the potential of opportunities for spatial interaction. Accessibility conceived in this manner should also capture spatial structure effects and thus the network configuration properties, such as connectivity. This conventional accessibility function—in the light of the related economic activities—is be used as a suitable instrument to identify the major German hub/attraction nodes. As the functional form in this potential accessibility, the power-decay function will be considered—in addition to the negative exponential function—in order to explore the spatial configuration patterns, i.e. whether people perceive commuting cost in log-like way. The connectivity network analysis will then be developed as a benchmark to testing the results emerging from the spatial-economic analysis. In our application we consider home-to-work commuters travelling between 439 German districts, for the year 2002. The final results seem to highlight the tendency, in Germany, towards a multi-nodality network, where accessibility can play a fundamental role.     

Risk assessment for organochlorines and organophosphates pesticide residues in water and Sediments from lower Nyando/Sondu‐Miriu river within Lake Victoria Basin,Kenya

The objective of this study was to survey and document pesticide residue levels in the lower Nyando/Sondu‐Miriu catchment areas of Lake Victoria, Kenya, during the dry and rainy seasons of 2009. Water and sediment samples from the Nyando/Sondu‐Miriu Basin were analysed for selected pesticide residues, using gas chromatography equipped with Ni⁶³ and CP‐SIL 8CB‐15m and TSD detectors for organochlorine and organophosphorus pesticide residues, respectively. The findings indicated that banned organochlorines are still being used in the catchment. Dieldrin and p,p′‐DDD were notably higher (P < 0.05) in concentrations than their metabolically formed analogues of aldrin and DDT, respectively. Notably, organophosphorus was below detection levels in water samples, whereas diazinon and malathion were at higher levels in sediment samples. The total residues of DDT, HCH, methoxychlor and endrin generally were below WHO drinking water limits of 2, 2, 20 and 0.01 μg L^?1, respectively, whereas aldrin and dieldrin were above the recommended values of 0.03 μg L^?1. Agricultural activities in the Lake Victoria Basin are influencing accumulation of the pesticide residues in the basin rivers and the lake. The study recommends creation of buffer zones around the natural water bodies to reduce the inflow of pesticides into water bodies. An integrated pest management approach that encourages reduced usage of chemical compounds also should be encouraged.