bluuebunny/crossref_metadata_2025 huggingface dataset:
Conjugated Polymer Based on Polycyclic Aromatics for Bulk Heterojunction Organic Solar Cells: A Case Study of Quadrathienonaphthalene Polymers with 2% Efficiency
Authors: Xiao Shengqiang , Stuart Andrew C. , Liu Shubin , Zhou Huaxing , You Wei
Published: January 2010

Polycyclic aromatics offer great flexibility in tuning the energy levels and bandgaps of resulting conjugated polymers. These features have been exploited in the recent examples of benzo[2,1‐b:3,4‐b']dithiophene (BDT)‐based polymers for bulk heterojunction (BHJ) photovoltaics (ACS Appl. Mater. Interfaces 2009, 1, 1613). Taking one step further, a simple oxidative photocyclization is used here to convert the BDT with two pendent thiophene units into an enlarged planar polycyclic aromatic ring—quadrathienonaphthalene (QTN). The reduced steric hindrance and more planar structure promotes the intermolecular interaction of QTN‐based polymers, leading to increased hole mobility in related polymers. As‐synthesized homopolymer (HMPQTN) and donor–acceptor polymer (PQTN‐BT) maintain a low highest occupied molecular orbital (HOMO) energy level, ascribable to the polycyclic aromatic (QTN) moiety, which leads to a good open‐circuit voltage in BHJ devices of these polymers blended with PCBM ([6,6]‐phenyl‐C61‐butyric acid methyl ester; HMPQTN: 0.76 V, PQTN‐BT: 0.72 V). The donor–acceptor polymer (PQTN‐BT) has a smaller optical bandgap (1.6 eV) than that of HMPQTN (2.0 eV), which explains its current (5.69 mA cm−2) being slightly higher than that of HMPQTN (5.02 mA cm−2). Overall efficiencies over 2% are achieved for BHJ devices fabricated from either polymer with PCBM as the acceptor.
Integration of a Chemical‐Responsive Hydrogel into a Porous Silicon Photonic Sensor for Visual Colorimetric Readout
Authors: Bonanno Lisa M. , DeLouise Lisa A.
Published: January 2010

The incorporation of a chemo‐responsive hydrogel into a 1D photonic porous silicon (PSi) transducer is demonstrated. A versatile hydrogel backbone is designed via the synthesis of an amine‐functionalized polyacrylamide copolymer where further amine‐specific biochemical reactions can enable control of cross‐links between copolymer chains based on complementary target–probe systems. As an initial demonstration, the incorporation of disulfide chemistry to control cross‐linking of this hydrogel system within a PSi Bragg mirror sensor is reported. Direct optical monitoring of a characteristic peak in the white light reflectivity spectrum of the incorporated PSi Bragg mirror facilitates real‐time detection of the hydrogel dissolution in response to the target analyte (reducing agent) over a timescale of minutes. The hybrid sensor response characteristics are shown to systematically depend on hydrogel cross‐linking density and applied target analyte concentration. Additionally, effects due to responsive hydrogel confinement in a porous template are shown to depend on pore size and architecture of the PSi transducer substrate. Sufficient copolymer and water is removed from the PSi transducer upon dissolution and drying of the hydrogel to induce color changes that can be detected by the unaided eye. This highlights the potential for future development for point‐of‐care diagnostic biosensing.
Kinetic investigation of the SO2 influence on NO reduction processes during methane reburning
Authors: Wang Xuebin , Tan Houzhang , Niu Yanqing , Chen Erqiang , Xu Tongmo
Published: January 2010

The reburning technique is an economical and highly efficient method for the reduction of NOx (nitrogen oxides) emissions. The University of Leeds (UK) proposed mechanism was used to investigate the effect of SO2 on the NO reduction during methane reburning in a plug flow reactor (CHEMKIN model) and compared with Glarborg's experimental data. The computational and experimental results show good agreement when there is no SO2 addition, and the highest NO reduction is obtained at the optimal air/fuel ratio 0.8. With SO2 addition, the optimal air/fuel ratio increases from 0.8 to 0.87 with an increase of SO2 concentration from 0 to 3000 ppm at a temperature of 1300 K. Under the fuel‐lean condition, the addition of SO2 slightly enhances the reduction of NO during methane reburning. Under the fuel‐rich condition, SO2 addition inhibits the reduction of NO when the air/fuel ratio is in the range of 0.65–1.0. However, when the air/fuel ratio is less than 0.65, then SO2 addition has negligible effect on NO reduction. The reaction mechanisms that influence the effect of SO2 on NO reduction were determined by the main controlling elementary reactions obtained from sensitivity analysis. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
An improved procedure for allocating public transit operating subsidies in Canada
Authors: Alfa Attahiru Sule , Clayton Diana
Published: January 2010

This article addresses the need for an improved methodology for the allocation of public transit operating subsidies (PTOS) by the provinces in Canada, to their respective municipalities. A PTOS allocation procedure which may be adapted by each province to meet its individual objectives is proposed. This allocation procedure consists of a two‐part grant, the first is population‐based in consideration of attributes of the urban area and the second is performance‐based, in consideration of attributes of the transit system itself. Issues of implementation concern primarily extended data collection methods and the need for consistency in the use of transit system performance measures.
Heuristic ranking and selection procedures for network design problems
Authors: Janson Bruce N. , Husaini Alaa
Published: January 2010

Two heuristic approaches to solving discrete non‐linear network design problems and other subset selection problems are described and tested. These heuristics operate similarly to other add, delete and interchange heuristics that have been applied to network design problems. However, the selection criterion adopted here is the ratio of objective function change per unit of resource cost, which other authors have described as an effective gradient measure for zero‐one integer programming problems. Optimal branch‐and‐bound algorithms previously developed and tested are reviewed, and those results serve as benchmarks with which to compare these heuristics described in this paper. The first heuristic ranks and deletes alternative network modifications from an entire set of candidate projects, such as new links or link improvements, until the subset of remaining projects fits within the constraint space. This method was found to achieve optimal or near‐optimal solutions to each of the test cases, even when the number of candidate projects deleted in each iteration was increased from one to many. The quality of those results led us to investigate a constrained random sampling procedure in which candidate projects are ranked with regard to randomly generated networks, and a solution is then chosen on the basis of these rankings. This second approach was found to achieve solutions that were almost as good as those obtained with the rank and delete heuristic.
A regression model for bus running times in suburban areas of winnipeg
Authors: Alfa Attahiru Sule , Menzies William B. , Purcha James , McPherson R.
Published: January 2010

To plan new bus routes in suburban areas, expected bus running times on these routes are needed. Using most readily available relevant variables, a regression model is developed for estimating bus running times. The model is conceptually reasonable and it was tested using data other than that used for estimation.
Marseilles integrated transport system
Authors: Croc Michel
Published: January 2010

To be fully effective, metro lines must be connected with other modes of transport. This principle has been applied in the city of Marseilles, France. First, a very good interchange between the two metro lines and the national and suburban railway has been developed in the Saint‐Charles main railway station. This interchange connects with the adjacent intercity bus terminal. Second, at every metro station, access facilities and neighborhood development were planned. Third, bus stations and car parks were installed at main rail stations. All this was made possible by early coordinated planning.
Analysis of heavy truck accident severity
Authors: Alassar Louai
Published: January 2010

This paper presents a macro empirical study of injuries and severity, and their contributory factors, for heavy truck accidents. This analysis is carried out through the examination of the fatal injury and non‐fatal injury odds ratio indices for a statistically best‐fit, log‐linear model. The statistical procedures used were the stepwise, backward elimination, log‐linear modeling with a critical significance level of 0.05. The analysis was conducted on the set of accident severity contributory independent variables (main‐effects) and all possible two‐way interactions of these variables (interaction effects) for articulated heavy trucks. Among the findings of the study is that it would appear to be more effective to decrease the accident rates for these trucks rather than to try to limit their resulting severities in attempting to reduce the toll of heavy truck accidents.
Signalized intersections with variable flow rates: II A model for delay estimation
Authors: Ceder Avishai , Dressler Ofer , Ross Thomas F.
Published: January 2010

This second part of our work develops a model for delay estimation at intersections whose traffic signal controls are continuously being updated. Generally, these traffic signals are centrally controlled. The foundation for the delay estimation model is based on a queuing theory model called “Preemptive resume discipline for M/G/1 with two priority levels.” This queuing model assumes that two customers arrive at acertain point by a Poisson arrival process, and that one customer has service priority over the second customer. The analogy for the case of intersection control is that the preferred customers are the red lights and the secondary customers are the vehicles. In order to adapt the model to the realistic behavior of vehicle traffic at continuously adjusted signals, components are derived to modify the model. The simulation results of the first part of this work are used to calculate adjustment factors that fairly accurately reproduce the simulated delays. This gives rise to the advantage of using in practice a closed mathematical model, in particular when trying to optimize the operation of signalized intersections at the network level.
Reliability, maintainability and availability of automatic people mover systems
Authors: Howell John K.
Published: January 2010

This paper covers reliability, maintainability, and availability theory and application to automated people mover (APM) systems. Reliability enhancements, obtained by employing high reliability and redundant functional components and assemblies and by achieving a high rate of repair, are covered.

The process of estimating subsystem and system reliability, based on component and assembly failure rates, is discussed. And the process for deriving subsystem and system availability and service availability is described.

APM failure monitoring, corrective actions, and recording and reporting systems and procedures are highlighted. Also, a brief discussion is presented on the subject of accountability of system reliability and availability.
Planning transportation innovations for livable cities: Auto‐Free zones and personal rapid transit
Authors: Haikalis George
Published: January 2010

The author advocates public support of innovation in transportation systems that would enhance the livability of cities. He calls for renewed exploration of the utility of introducing auto‐free zones in dense urban places, and the initiation of development of a PRT‐like system that could ultimately displace the free‐wheeling motor vehicle in these places.
Multinomial mode choice models for Atlanta airport passenger movement
Authors: Kumarage A. S. , Wirasinghe S. C.
Published: January 2010

Automated people movers (APM's) and moving‐sidewalks (belts) are used to reduce passenger walking distances within airport terminal systems. In this paper, mode choice for intra‐terminal travel by the three modes: APM, belt and walk, is modelled using partially disaggregate trinomial logit and probit models. The utility functions of these models are computed in terms of units of time, separated into time spent walking and time spent standing. The models are used to analyze travel to the proposed concourse E at Atlanta's Hartsfield Airport.
Accidents of elderly drivers and intersection traffic control devices
Authors: Stamatiadis Nikiforos , Taylor William C. , Mckelvey Francis X.
Published: January 2010

The research reported in this paper examined the relationship between accidents of elderly drivers and intersection traffic control devices. The analysis was performed using the induced exposure method, where the exposure to an accident is defined as the probability of being the driver not cited for the accident occurrence. The results indicate that the accident involvement of elderly drivers is higher than that of the other drivers under certain circumstances. To reduce these rates modifications in the licensing procedures and training programs are suggested.
Eliminating rank reversal in multicriteria analysis of urban transportation system alternatives
Authors: Gomes Luiz F. A. M.
Published: January 2010

This note shows how to eliminate rank reversal in practical applications of TODIM, a method for multicriteria ranking of projects. A technique for eliminating rank reversal is then utilized in applications of both TODIM and AHP to the same data base. A comparison of results suggests that those two alternative methods tend to lead to the same results.
The traffic connection between airports and city centers
Authors: Rallis Tom , Peen Jens
Published: January 2010

This article deals with some parts of the issue “Traffic connection between airport and city centers”. Two case studies are given: London and Copenhagen. These two have many parallels in their development. The issue is rather complex and the increasing implementation of high‐speed trains offering a high door‐to‐door speed, will change the development of many airports, especially those that already have problems with the access‐egress transport capacity.
Sustainability: A vital concept for transportation planning and development
Authors: Replogie Michael
Published: January 2010

The current pattern of metropolitan transportation and land development in the majority of countries around the world appears to be increasingly unsustainable from both an economical and environmental perspective. Many factors point to the need for adoption of a new paradigm for sustainable transportation and development in both high and low income countries—burgeoning populations, growing air pollution, limits on global petroleum reserves, limited physical and economic capacity to expand automobile‐based transportation systems without community destruction, and the urgent need to limit global CO2 emissions to slow the pace of global warming.

This paper outlines some of the conceptual differences between the current paradigm for transportation planning and an emerging paradigm for sustainable transportation and land development. It compares the US and European patterns of transport and land development, which often inspire transportation decision‐makers and planners in developing countries. The paper reviews the patterns of development in the cities of several developing countries, identifying policies than can enhance sustainability.
Development of interregional cooperation in the field of urban and suburban transport under the auspices of the UN
Authors: Storchevus Vladimir K.
Published: January 2010

The article considers specific features, the importance and the problems of urban and suburban transport with reference to international economic, scientific and technological cooperation. It also describes methods and means for utilizing the opportunities for cooperation within the framework of the UN Regional Economic Commissions with a more active involvement of CODATU and UNCHS (Habitat) and the Habitat Executive Bureau in Moscow. The article identifies and classifies the main tasks of the development of urban public transport in cities with varying degree of motorization as well as identifies the priorities of international cooperation within the UN.
An AI‐based approach for transit route system planning and design
Authors: Baaj M. Hadi , Mahmassani Hani S.
Published: January 2010

We present an AI‐based solution approach to the transit network design problem (TNDP). Past approaches fall into three categories: optimization formulations of idealized situations, heuristic approaches, or practical guidelines and ad hoc procedures reflecting the professional judgement and practical experience of transit planners. We discuss the sources of complexity of the TNDP as well as the shortcomings of the previous approaches. This discussion motivates the need for AI search techniques that implement the existing designer's knowledge and expertise to achieve better solutions efficiently. Then we propose a hybrid solution approach that incorporates the knowledge and expertise of transit network planners and implements efficient search techniques using AI tools, algorithmic procedures developed by others, and modules for tools implemented in conventional languages. The three major components of the solution approach are presented, namely, the lisp‐implemented route generation design algorithm (RGA), the analysis procedure TRUST (Transit Route Analyst), and the route improvement algorithm (RIA). An example illustration is included.
The morgantown PRT: It is still running at West Virginia University
Authors: Sproule William J. , Neumann Edward S.
Published: January 2010

It has been over fifteen years since the Morgantown PRT system went into passenger service. Its start was marked by cost overruns, high operating costs and poor reliability. However over time, these initial problems and difficulties have been overcome, and today the system provides an extremely important and reliable service that links downtown Morgantown with three campuses of West Virginia University. It is still running. This paper provides background on the development of the system and current operating characteristics of this famous transit demonstration project.
Suburbanization of jobs and the journey to work: A submarket analysis of commuting in the San Francisco bay area
Authors: Cervero Robert , Landis John
Published: January 2010

Inrecent years, a debate has brewed over whether the decentralization of employment has been beneficial from a regional standpoint. In this article, we focus on one aspect of the debate: how the relocation of office workers from a downtown to a suburban location affects commuting patterns and mode choice. From a survey of 320 former downtown San Francisco workers who now work in the suburbs, we found that the average distance traveled remained essentially unchanged and that the average commuting speed increased. The most dramatic change, however, was the switch from public transit to drive‐alone commuting. In the aggregate, we estimate that the change in job location was associated with nearly a threefold increase in vehicle miles traveled to work. While from a personal standpoint, employees seemed better off since they got to work faster and more comfortably, from a larger social and environmental perspective, the costs could be significant. More detailed analyses of commuter submarkets revealed that the transportation impacts vary considerably depending on whether the original residence was in the suburbs or central city and whether relocated workers had moved their residences in recent years. In general, those who remained in San Francisco and became reverse commuters were worst off whereas those who moved their residences out of the city were much better off in terms of job access. The article concludes that road pricing would be the best way to force motorists to internalize the external costs of increased drive‐alone commuting. Second‐best options would be to introduce development impact fees or employer‐based trip reduction regulations.
Advanced transportation economic development
Authors: Stern Larry
Published: January 2010

The end of the cold war and confrontational politics of the eastern and western worlds have raised the possibility that resources formerly targeted toward military systems and options may be turned towards global lifestyle improvements [OTA, 1993]. Transportation has been one of the fields proposed as a likely candidate for both improvements and jobs. It is not possible to address economic development in the context of all transportation in one essay. For this reason I am only addressing the issues of economic development associated with mass transportation characteristic of urban and interurban environments.

Realigning former defense resources to mass transit requires careful consideration of market conditions. According to economic survey data published by the Economic Roundtable in Los Angeles, there are currently less than 40,000 manufacturing jobs in the U.S. rail transportation industry [Drayse, 1993]. The same survey pointed out a severe mismatch between the skill base required by the rail industry and available defense technology resources. There exists no large base of unsatisfied demand in the rail market, therefore development of a large number of jobs is not likely if the approach is simply to introduce additional competing resources into a traditional market [Monitor, 1993].
Child pedestrian fatalities: The size of the problem and some suggested countermeasures
Authors: Preston Barbara
Published: January 2010

The child pedestrian death rates, per 100,000 population, for the USA and 22 European countries are compared. The safety measures used in some of these countries, for the two key areas of danger for children, the school journey and the residential environment, are outlined. Problems that might prevent the introduction of these countermeasures in some other countries are discussed.

It is recommended that: 1) there should be special low speed limits on the roads outside all schools. On minor roads traffic calming measures would be suitable, on main roads new speed limits could be introduced and enforced by police surveillance using video camera techniques. 2) In suitable residential areas children should be enabled to play out in safety on the streets near their homes. In some countries the most acceptable way of achieving this might be by a change in the law whereby children would have priority in these designated Home Zones.
Level of public transport service evaluation: A fuzzy set approach
Authors: Murugesan R. , Moorthy N. V. Rama
Published: January 2010

The success of any enterprise, in a market‐oriented economy, depends upon it's quality. This paper describes the results of a survey of commuters on the quality of services and their relative weights, and of the attributes that determine the service level of bus transport undertakings. The model uses the theory of fuzzy sets to process the information obtained. A composite index, called level‐of‐public transport‐service (LOPTS), is defined and used to measure the service qualities. This approach is presented with guidelines for rating the quality of services, fuzzy‐set representations of the linguistic grades, definition of LOPTS and its use in a public transport quality data base. An example is presents how the approach can be employed to analyse data bases generated from a quality survey. This approach is compared with the numerical rating approach with single number representation.
Thiol redox status critically influences mitochondrial response to thyroid hormone‐induced hepatic oxidative injury: A temporal analysis
Authors: Chattopadhyay Sutapa , Sahoo Dipak K. , Roy Anita , Samanta Luna , Chainy Gagan B.N.
Published: January 2010

Liver is a major target organ for thyroid hormone. The objective of the present study was to investigate temporal regulation of mitochondrial glutathione and protein‐bound thiol redox status in hyperthyroid liver. Mitochondria were isolated from control and hyperthyroid rat liver tissues at different time intervals, i.e., 24, 72, and 120 h following treatment, and sub‐fractionated into sub‐mitochondrial particles (SMPs) and matrix fractions. Increased prooxidant levels were indicative of oxidative stress in hyperthyroid mitochondria. Sensitivity to membrane lipid peroxidation (LPx) was maximal after 24 h, which subsided with time. Oxidative damage to proteins was evident as high carbonylation after 72 h; thiol residue damage was an early phenomenon. Reduced and oxidized glutathione (GSH and GSSG) pools of mitochondria were progressively depleted, thereby, impairing matrix antioxidant capacity. However, adaptations to withstand oxidative challenge were elicited in both SMPs and matrix fractions over the long term. It is concluded that maintenance of appropriate intra‐mitochondrial glutathione and protein‐bound thiol redox status could be instrumental in attenuating thyroid hormone‐induced oxidative stress. Copyright © 2010 John Wiley & Sons, Ltd.
The actions of fisetin on glucose metabolism in the rat liver
Authors: Constantin Rodrigo Polimeni , Constantin Jorgete , Pagadigorria Clairce Luzia Salgueiro , Ishii‐Iwamoto Emy Luiza , Bracht Adelar , Ono Mariana de Kássia Cardoso , Yamamoto Nair Seiko
Published: January 2010

Fisetin is a flavonoid dietary ingredient found in the smoke tree (Cotinus coggyria) and in several fruits and vegetables. The effects of fisetin on glucose metabolism in the isolated perfused rat liver and some glucose‐regulating enzymatic activities were investigated. Fisetin inhibited glucose, lactate, and pyruvate release from endogenous glycogen. Maximal inhibitions of glycogenolysis (49%) and glycolysis (59%) were obtained with the concentration of 200 µM. The glycogenolytic effects of glucagon and dinitrophenol were suppressed by fisetin 300 µM. No significant changes in the cellular contents of AMP, ADP, and ATP were found. Fisetin increased the cellular content of glucose 6‐phosphate and inhibited the glucose 6‐phosphatase activity. Gluconeogenesis from lactate and pyruvate or fructose was inhibited by fisetin 300 µM. Pyruvate carboxylation in isolated intact mitochondria was inhibited (IC50 = 163.10 ± 12.28 µM); no such effect was observed in freeze‐thawing disrupted mitochondria. It was concluded that fisetin inhibits glucose release from the livers in both fed and fasted conditions. The inhibition of pyruvate transport into the mitochondria and the reduction of the cytosolic NADH‐NAD+ potential redox could be the causes of the gluconeogenesis inhibition. Fisetin could also prevent hyperglycemia by decreasing glycogen breakdown or blocking the glycogenolytic action of hormones. Copyright © 2010 John Wiley & Sons, Ltd.
Effects of ammonia and allopurinol on rat hippocampal NMDA receptors
Authors: Yonden Zafer , Aydin Mehmet , Kilbas Aynur , Demirin Hilmi , Sutcu Recep , Delibas Namik
Published: January 2010

Ammonia is considered to be the main agent responsible for hepatic encephalopathy which progressively leads to altered mental status.N‐methyl‐D‐aspartate (NMDA) is an ionotropic glutamate receptor, which is involved in synaptogenesis, memory and neurotoxicity. The aim of this study was to investigate the effects of ammonia intoxication and allopurinol, a xanthine oxidase (XO) inhibitor, on NMDA receptor subunits, NR2A and NR2B, in the hippocampus of rats. Thirty‐six male rats were divided into three groups (n = 12/group) as follows: (1)control group (phosphate buffered saline (PBS) solution); (2)ammonia group (ammonium acetate, 2.5 mmol/kg), (3)ammonia + allopurinol group (ammonium acetate, 2.5 mmol/kg, allopurinol, 50 mg/kg). Each rat received intraperitoneal injection for 28 days. Western Blotting technique was used for detecting NR2A and NR2B expressions. Both NR2A and NR2B subunit expressions decreased 27 and 11%, respectively, in ammonia group with respect to the control group. Ammonium acetate decreased significantly in NR2A subunit expressions in the hippocampus (p < 0.01). Administration of ammonia + allopurinol caused statistically significant increases in NR2A subunit expressions compared to the ammonia group (p < 0.001). The down‐regulation of NMDA receptors caused by ammonium acetate suggest that these receptors may play role in the process of hepatic encephalopathy and using allopurinol may have some protective effects in ammonia toxicity. Copyright © 2010 John Wiley & Sons, Ltd.
Bacoside A downregulates matrix metalloproteinases 2 and 9 in DEN‐induced hepatocellular carcinoma
Authors: Janani Panneerselvam , Sivakumari Kanakarajan , Geetha Arumugam , Yuvaraj Sambandam , Parthasarathy Chandrakesan
Published: January 2010

Cancer metastasis is a complex multi‐step process, responsible for a majority of cancer‐related deaths by affecting the critical organs and causing complications in therapies. Hepatocellular carcinoma is a multi‐factorial disease and is the third most common cause of cancer related mortality worldwide. Clinical and experimental studies have shown that MMP‐2 and MMP‐9 are involved in tumor invasion and metastases and their elevated expression has been associated with poor prognosis. Our recent studies showed a strong anti‐oxidant and hepatoprotective effects of bacoside A (BA) against carcinogen. Nevertheless the effect of BA on the activities and expression of MMP‐2 and MMP‐9 during hepatocellular carcinoma is not yet recognized. Therefore, the present study was designed to assess the same. Results of gelatin zymography study showed that BA co‐treatment significantly decreased the activities of MMP‐2 and MMP‐9, which is increased during hepatocellular carcinoma. Further immunoblot analysis showed decreased expression of MMP‐2 and MMP‐9 in rats co‐treated with BA compared to DEN‐induced hepatocellular carcinoma. Our results reveal that BA exerts its anti‐metastatic effect against DEN‐induced hepatocellular carcinoma by inhibiting the activities and expressions of MMP‐2 and MMP‐9. Copyright © 2010 John Wiley & Sons, Ltd.
Carbon Nanotube and Gold‐Based Materials: A Symbiosis
Authors: Singh Rajpal , Premkumar Thathan , Shin Ji‐Young , Geckeler Kurt E.
Published: January 2010

Carbon nanotubes constitute a novel class of nanomaterials with potential applications in many areas. The attachment of metal nanoparticles to carbon nanotubes is new way to obtain novel hybrid materials with interesting properties for various applications such as catalysts and gas sensors as well as electronic and magnetic devices. Their unique properties such as excellent electronic properties, a good chemical stability, and a large surface area make carbon nanotubes very useful as a support for gold nanoparticles in many potential applications, ranging from advanced catalytic systems through very sensitive electrochemical sensors and biosensors to highly efficient fuel cells. Here we give an overview on the recent progress in this area by exploring the various synthesis approaches and types of assemblies, in which nanotubes can be decorated with gold nanoparticles and explore the diverse applications of the resulting composites.
The Structure of a Novel Neutral Lipid A from the Lipopolysaccharide of Bradyrhizobium elkanii Containing Three Mannose Units in the Backbone
Authors: Komaniecka Iwona , Choma Adam , Lindner Buko , Holst Otto
Published: January 2010

The chemical structure of the lipid A of the lipopolysaccharide (LPS) from Bradyrhizobium elkanii USDA 76 (a member of the group of slow‐growing rhizobia) has been established. It differed considerably from lipids A of other Gram‐negative bacteria, in that it completely lacks negatively charged groups (phosphate or uronic acid residues); the glucosamine (GlcpN) disaccharide backbone is replaced by one consisting of 2,3‐dideoxy‐2,3‐diamino‐D‐glucopyranose (GlcpN3N) and it contains two long‐chain fatty acids, which is unusual among rhizobia. The GlcpN3N disaccharide was further substituted by three D‐mannopyranose (D‐Manp) residues, together forming a pentasaccharide. To establish the structural details of this molecule, 1D and 2D NMR spectroscopy, chemical composition analyses and high‐resolution mass spectrometry methods (electrospray ionisation Fourier‐transform ion cyclotron resonance mass spectrometry (ESI FT‐ICR MS) and tandem mass spectrometry (MS/MS)) were applied. By using 1D and 2D NMR spectroscopy experiments, it was confirmed that one D‐Manp was linked to C‐1 of the reducing GlcpN3N and an α‐(1→6)‐linked D‐Manp disaccharide was located at C‐4′ of the non‐reducing GlcpN3N (α‐linkage). Fatty acid analysis identified 12:0(3‐OH) and 14:0(3‐OH), which were amide‐linked to GlcpN3N. Other lipid A constituents were long (ω‐1)‐hydroxylated fatty acids with 26–33 carbon atoms, as well as their oxo forms (28:0(27‐oxo) and 30:0(29‐oxo)). The 28:0(27‐OH) was the most abundant acyl residue. As confirmed by high‐resolution mass spectrometry techniques, these long‐chain fatty acids created two acyloxyacyl residues with the 3‐hydroxy fatty acids. Thus, lipid A from B. elkanii comprised six acyl residues. It was also shown that one of the acyloxyacyl residues could be further acylated by 3‐hydroxybutyric acid (linked to the (ω‐1)‐hydroxy group).
Session‐based end‐to‐end policy control in 3GPP evolved packet system
Authors: Good Richard , de Gouveia Fabricio Carvalho , Ventura Neco , Magedanz Thomas
Published: January 2010

The Third Generation Partnership Project specifies a solution to handle the heterogeneity of future networks, including quality of service (QoS) and charging aspects. This solution utilizes a policy‐based approach based on the policy and charging control (PCC) architecture, which is an integral component of the evolved packet system (EPS). The specifications for EPS are being finalized with the evolved packet core (EPC) central to this framework. The EPC is a simplified, flat, all IP‐based architecture that supports mobility between heterogeneous access networks and incorporates an evolved QoS concept based on the PCC framework. A critical open issue within EPS is the provisioning of end‐to‐end QoS enabled paths. This article proposes enhancements to the EPC/PCC framework that extend the end‐to‐end inter‐domain mechanisms to discover the signaling routes at the service control layer, and use this information to determine the paths traversed by the media at the resource control layer. Because the approach operates at these layers, it is compatible with existing transport networks and exploits already existing QoS control mechanisms. A real testbed implementation, comprising free and open source software, is used to evaluate the proposed mechanisms. The obtained results show that the framework has an acceptable effect on session setup delay and core traffic overhead in a range of scenario ranging from simple, to typical, to worst case. Copyright © 2010 John Wiley & Sons, Ltd.
An implementation and performance evaluation of kernel‐level RTP supporting the BSD socket API
Authors: Park Sang Oh , Choi Mun Seon , Kim Sung Jo
Published: January 2010

RTP (Real‐time Transport Protocol) has been designed for efficient transmission of real‐time multimedia data on the Internet by Internet Engineering Task Force (IETF). Different applications tend to implement separate RTPs as a library. In order to resolve this problem,embeddedRTPwas proposed as an RTP‐based kernel‐level protocol. This paper proposes theExtendedERTPprotocol based on theembeddedRTPprotocol. This new protocol deals with a couple of issues, such as packet processing overhead and buffer requirement, and combines its Application Programming Interface (API) with Berkeley Software Distribution (BSD) socket's which have been widely utilized in network applications. This paper demonstrates that this integration makes it possible to transmit real‐time multimedia data through the existing interface of BSD socket API with nominal extra overhead. This paper also shows that the time and memory requirement for packet processing can be reduced by about 15–20% and by 3.5%, respectively, compared with those ofembeddedRTP. Copyright © 2010 John Wiley & Sons, Ltd.
Icosahedral Ga‐Centred Nickel Carbonyl Clusters: Synthesis and Characterization of [H3–nNi12 (μ12‐Ga)(CO)22]n– (n = 2, 3) and [Ni14.3(μ12‐Ga)(CO)24.3]3– Anions
Authors: Femoni Cristina , Iapalucci Maria Carmela , Longoni Giuliano , Zacchini Stefano
Published: January 2010

The reaction of [Ni5(CO)12]2– or [Ni6(CO)12]2– with GaCl3 in dichloromethane under a nitrogen atmosphere affords a mixture of [Ni12+x(μ12‐Ga)(CO)22+x]3– (x = 0–3) clusters. Short exposure of the above mixture to a carbon monoxide atmosphere leads to the green icosahedral [Ni12(μ12‐Ga)(CO)22]3– trianion, which was isolated and characterized as its [NnBu4]+ salt. In contrast, crystallization of the above mixture in the presence of Ni(CO)4 enabled isolation of a cocrystallized mixture of [Ni14(μ12‐Ga)(CO)24]3– (70 %) and [Ni15(μ12‐Ga)(CO)25]3– (30 %). As inferable from its structure, the additional three Ni(CO) moieties condense onto interlayer faces of the icosahedron. Protonation of [Ni12(μ12‐Ga)(CO)22]3– affords the corresponding [HNi12(μ12‐Ga)(CO)22]2– hydride derivative, which was isolated in a pure state and fully characterized. All of the above compounds conform to the cluster‐borane analogy, by the inclusion principle, and none exhibits relevant redox behaviour.
Niobate and Tantalate Pyrochlores: Soft Synthesis by the Fluoride Route
Authors: Britvin Sergey N. , Siidra Oleg I. , Lotnyk Andriy , Krivovichev Sergey V. , Depmeier Wulf
Published: January 2010

A series of pyrochlores A(Nb,Ta)2(O,OH,F)6(nH2O), (A = NH4, K, Rb, Cs) have been synthesized by hydrolysis of aqueous solutions of oxofluoroniobic (H2NbOF5) and fluorotantalic (H2TaF7) acids. This new method allows preparation of nanocrystalline niobate pyrochlores (crystal size 10–20 nm) by simple precipitation with subsequent boiling; tantalate analogues can be obtained by soft hydrothermal treatment. The synthesized compounds include new pyrochlores NH4Nb2O5(OH,F), NH4Ta2O5(OH,F)·nH2O and K1–xNb2(O,OH)5F·nH2O as well as the already known CsNb2O5F, Rb1–xNb2(O,OH)5F, CsTa2O5F and their hydroxyl analogues. Ion‐exchange experiments revealed that K0.7Nb2(O,OH)5F·nH2O exhibits strong selective uptake of Pb2+ from aqueous solutions, a feature not previously reported for pyrochlores. The facilitating role of fluoride ions in the synthesis of pyrochlores is discussed in comparison with zeolite synthesis, and the technological applicability of the new method is also presented in the paper.
Reaction of a Stable Conjugated Primary Enamine with Piers' Borane
Authors: Peuser Ilona , Fröhlich Roland , Kehr Gerald , Erker Gerhard
Published: January 2010

Treatment of 1,6‐diamino‐1,6‐diphenyl‐1,3,5‐hexatriene (3) with 2 mol‐equiv. of HB(C6F5)2results in tautomerization of the stable primary enamine to its bis(imine) tautomer, which is stabilized by twofold imine/borane Lewis base/Lewis acid adduct formation to yield an 11:6:1 mixture ofE,E‐5,E,Z‐5andZ,Z‐5. Within several hours at room temperature, these systems undergo subsequent hydroboration of the central remaining C=C double bond followed by internal imine–alkylborane coordination to yield the six‐membered N,B heterocycle6featuring a pendant –CH2–C(Ph)=NH[B(H)(C6F5)2] group. Compound6was characterized by X‐ray diffraction.
Synthesis of Fullerene‐Stoppered Rotaxanes Bearing Ferrocene Groups on the Macrocycle
Authors: Mateo‐Alonso Aurelio , Prato Maurizio
Published: January 2010

The synthesis, characterisation and behaviour of a series of rotaxanes containing a fulleropyrrolidine stopper and two ferrocene moieties on the macrocycle is reported. Remarkably, the presence of large and bulky ferrocene groups does not interfere either in the synthesis or in the translocation of the macrocycle induced by π–π interactions between the macrocycle and the fullerene. The synthetic routes developed can also be applied to the preparation of rotaxane scaffolds that can be complexed to [Ru(CO)TPP] by axial coordination. Overall, the synthetic routes presented herein provide an efficient way to prepare a variety of rotaxanes and molecular shuttles with potential applications in different fields.
Shear‐rate‐dependent strength control on the dynamics of rainfall‐triggered landslides, Tokushima Prefecture, Japan
Authors: Wang Gonghui , Suemine Akira , Schulz William H.
Published: January 2010

A typhoon (Typhoon No. 10) attacked Shikoku Island and the Tyugoku area of Japan in 2004. This typhoon produced a new daily precipitation record of 1317 mm on Shikoku Island and triggered hundreds of landslides in Tokushima Prefecture. One catastrophic landslide was triggered in the Shiraishi area of Kisawa village, and destroyed more than 10 houses while also leaving an unstable block high on the slope. The unstable block kept moving after the event, showing accelerating and decelerating movement during and after rainfall and reaching a displacement of several meters before countermeasures were put into place. To examine the mechanism for this landsliding characteristic, samples (weathered serpentinite) were taken from the field, and their shear behaviours examined using ring shear tests. The test results revealed that the residual shear strength of the samples is positively dependent on the shear rate, which may provide an explanation for the continuous accelerating–decelerating process of the landsliding. The roughness of the shear surface and the microstructure of the shear zone were measured and observed by laser microscope and SEM techniques in an attempt to clarify the mechanism of shear rate effect on the residual shear strength. Copyright © 2010 John Wiley & Sons, Ltd.
The impact of agriculture on solute and suspended sediment load on a Mediterranean watershed after intense rainstorms
Authors: Outeiro Luís , Úbeda Xavier , Farguell Joaquim
Published: January 2010

The solute and suspended‐sediment load following five rainstorms (2005–2007) with varied intensities were studied at the Vernegà experimental watershed, north‐western Spain. Two land‐use areas are located within this watershed, the upstream one (forest) with 160 ha a 100% forested area, and the downstream one (agricultural) with 97 ha being 9 ha conventional agricultural field and 88 ha forest. This study investigates the capacity of each land‐use to yield water, suspended sediment concentration (SSC) and dissolved solid concentration (DSC). The hypothesis is that DSC and SSC from the agricultural area are greater than DSC and SSC of the forest area. Results showed that the agriculture area produced significantly greater mean DSC than in the forest area, the main contribution was the Ca2+ (24·68 ± 46·52 mg l−1) ion at the agricultural area. A long‐term sediment production rate at the agricultural outlet was calculated (69·1 tonnes per 100 years) based on the total sediment discharge (TSD) and the recurrence interval of the largest event of the five rainstorms (October 2005). Geographic information system (GIS) spatial data layers of the watershed were produced to determine the relation of tracks, landforms, slopes and forest management to SSC yield in the forest outlet (133·89 ± 308·14 mg l−1) during the five rainstorms. Agriculture practices are the main cause of soil erosion at the study area. Copyright © 2010 John Wiley & Sons, Ltd.
Upper Pleistocene‐Holocene geomorphic changes dictating sedimentation rates and historical land use in the valley system of the Chifeng region, Inner Mongolia, northern China
Authors: Avni Y. , Zhang J. F. , Shelach G. , Zhou L. P.
Published: January 2010

This study focuses on the late Quaternary landscape evolution in the Chifeng region of Inner Mongolia, China, its relations to the history of the Pleistocene‐Holocene loess accumulation, erosion and redeposition, and their impact on human occupation.

Based on 57 optically stimulated luminescence (OSL) ages of loess sediments, fluvial sand and floodplain deposits accumulated on the hill slopes and floodplains, we conclude that during most of the Pleistocene period the region was blanketed by a thick layer of aeolian loess, as well as by alluvial and fluvial deposits. The loess section is divided into two main units that are separated by unconformity. The OSL ages at the top of the lower reddish loess unit yielded an approximate age of 193 ka, roughly corresponding to the transition from MIS 7 to 6, though they could be older. The upper gray loess unit accumulated during the upper Pleistocene glacial phase (MIS 4–3) at a mean accumulation rate of 0·22 m/ka. Parallel to the loess accumulation on top of the hilly topography, active fans were operating during MIS 4–2 at the outlet of large gullies surrounding the major valley at a mean accumulation rate of 0·24 m/ka. This co‐accumulation indicates that gullies have been a long‐term geomorphic feature at the margins of the Gobi Desert since at least the middle Pleistocene. During the Holocene, the erosion of the Pleistocene loess on the hills led to the burial of the valley floors by the redeposited sediments at a rate that decreases from 3·2 m/ka near the hills to 1–0·4 m/ka1in the central part of the Chifeng Valley. This rapid accumulation and the frequent shifts of the courses of the river prevented the construction of permanent settlements in the valley floors, a situation which changed only with improved man‐made control of the local rivers from the tenth century AD. Copyright © 2010 John Wiley & Sons, Ltd.
Antioxidant activity of six Portuguese thyme species essential oils
Authors: Dandlen S. Anahi , Lima A. Sofia , Mendes Marta D. , Miguel M. Graça , Faleiro M. Leonor , Sousa M. João , Pedro Luis G. , Barroso José G. , Figueiredo A. Cristina
Published: January 2010

The essential oils of Thymus caespititius, T. camphoratus, T. capitellatus, T. carnosus, T. pulegioides, T. zygis subsp. zygis and T. zygis subsp. sylvestris collected in different regions of Portugal, including the Azores islands, were evaluated for preventing lipid peroxidation and scavenging free radicals, and hydroxyl and superoxide anions. T. zygis subsp. zygis oil possessed the best capacity for preventing lipid peroxidation (IC50 = 0.030 ± 0.003 mg/ml), immediately followed by the oils isolated from T. zygis subsp. sylvestris collected in different regions of Portugal. IC50 values ranged from 0.066 ± 0.003 to 0.087 ± 0.001 mg/ml in oils isolated from samples from Alcanena and Duas Igrejas, respectively. The oils isolated from T. zygis subsp. sylvestris, independent of the harvesting region, were shown to be the most effective for scavenging free radicals (0.358–0.453 mg/ml). The best capacity for scavenging hydroxyl radicals was found in the oils of T. camphoratus collected in Espartal and of T. caespititius of Lordelo, with IC50 < 0.5 mg/ml. The low oil amount did not allow IC50 values for the superoxide anion scavenging determination, therefore considering a unique oil concentration (5 mg/ml), the highest inhibition percentages (?50%) were registered with the essential oils of T. zygis subsp. sylvestris from Duas Igrejas and Covão do Coelho, and of T. capitellatus from Sines. Copyright © 2010 John Wiley & Sons, Ltd.
Variable selection in STAR models with neighbourhood effects using genetic algorithms
Authors: Alberto Isolina , Beamonte Asunción , Gargallo Pilar , Mateo Pedro M. , Salvador Manuel
Published: January 2010

In this paper we deal with the problem of variable selection in spatiotemporal autoregressive (STAR) models with neighbourhood effects. We propose a procedure to carry out the selection process, taking into account the uncertainty associated with estimation of the parameters and the predictive behaviour of the compared models, in order to give more realism to the analysis. We set up a multi‐objective programming problem that combines the use of different criteria to measure both these aspects. We use genetic algorithms which are very flexible and suitable for our multicriteria decision problem. In particular, the procedure allows us to estimate the number of spatial and temporal nearest neighbours as well as their relative effects. The methodology is illustrated through an application to the real estate market of Zaragoza. Copyright © 2010 John Wiley & Son, Ltd.