bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of microphase‐separated solvent‐free solid polymer electrolyte nanocomposite films using amphiphilic urethane acrylate precursors
Authors: Kim Ju‐Young , Han Kweon‐Hyung , Suh Kyung‐Do , Ihn Kyo‐Jin 
Published: July 2007

AbstractA new solvent‐free solid polymer electrolyte (SPE) films could be fabricated through bulk copolymerization process of amphiphilic urethane acrylate nonionomer (UAN). Amphiphilic UAN chain having polypropylene oxide‐based hydrophobic segment and polyethylene oxide‐based hydrophilic segment can not only dissolve lithium salt by complex formation with lithium cations but also be copolymerized with various monomers to form microphase‐separated polymeric matrix. Unlike conventional SPE systems showing higher conductivity with polar polymers and polar solvents, our SPE films prepared by copolymerization of UAN and hydrophobic monomers exhibited relatively higher conductivity. Dissolving lithium salts in UAN/hydrophobic monomer mixtures caused hydrophilic/hydrophobic microphase separation, which was more favorable for ionic conduction of lithium ions, resulting in the higher ionic conductivity than the SPE films fabricated using UAN/hydrophobic monomer mixture. This microphase‐separated structure of SPE films could be also confirmed by transmission electron microscope (TEM) images. Ionic conductivity of our SPE films could be also improved by dispersing clay minerals within SPE films. Three types of clay having different surface properties were used to fabricate clay/SPE nanocomposite films. Ionic conductivity of nanocomposite films depended on dispersibliity of clay nanoparticles with a SPE film, which was confirmed by measuring X‐ray diffraction and TEM. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Enantioselective Organocatalysis Using SOMO Activation
Authors: Beeson Teresa D. , Mastracchio Anthony , Hong Jun‐Bae , Ashton Kate , MacMillan David W. C. 
Published: July 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
AT1Receptor Ligands: Virtual‐Screening‐Based Design with TOPP Descriptors, Synthesis, and Biological Evaluation of Pyrrolidine Derivatives
Authors: Lamanna Claudia , Catalano Alessia , Carocci Alessia , Di Mola Antonia , Franchini Carlo , Tortorella Vincenzo , Vanderheyden Patrick M. L. , Sinicropi Maria S. , Watson Kimberly A. , Sciabola Simone 
Published: July 2007

AbstractAs a continuing effort to establish the structure–activity relationships (SARs) within the series of the angiotensin II antagonists (sartans), a pharmacophoric model was built by using novel TOPP 3D descriptors. Statistical values were satisfactory (PC4:r2=0.96,q2(5randomgroups)=0.84; SDEP=0.26) and encouraged the synthesis and consequent biological evaluation of a series of new pyrrolidine derivatives. SAR together with a combined 3D quantitative SAR and high‐throughput virtual screening showed that the newly synthesized 1‐acyl‐N‐(biphenyl‐4‐ylmethyl)pyrrolidine‐2‐carboxamides may represent an interesting starting point for the design of new antihypertensive agents. In particular, biological tests performed on CHO‐hAT1cells stably expressing the human AT1receptor showed that the length of the acyl chain is crucial for the receptor interaction and that the valeric chain is the optimal one.
Metronidazole–Flavonoid Derivatives as Anti‐Helicobacter pyloriAgents with Potent Inhibitory Activity against HPE‐Induced Interleukin‐8 Production by AGS Cells
Authors: Li Huan‐Qiu , Xu Chen , Li Hong‐Sen , Xiao Zhu‐Ping , Shi Lei , Zhu Hai‐Liang 
Published: July 2007

AbstractThree series of metronidazole–flavonoid derivatives were generated and evaluated for antimicrobial activity againstH. pylori. Among these compounds, high anti‐H. pyloriactivities were observed in isoflavones derivatives4–7,19, and20but exhibited no inhibitory activity against other sorts of bacteria and fungi, for example,Streptococcus pneumoniae, Bacillus subtilis, Escherichia coli, Pseudomonas fluorescence, andAspergillus niger. Genistein derivative6with the potent activity (MIC=0.39 μg mL−1) was >50‐fold more than metronidazole, and comparable to the positive control amoxicillin. Additionally, compound6can significantly attenuate the increase in interleukin‐8 (IL‐8) levels in the AGS cells stimulated byH. pyloriwater extract (HPE) at concentrations of 15, 30, and 60 μmol L−1, which did not show any effects on the cell viability.
Active surveillance for selected patients with renal masses
Authors: Abou Youssif Tamer , Kassouf Wassim , Steinberg Jordan , Aprikian Armen G. , Laplante Micheal P. , Tanguay Simon 
Published: July 2007

AbstractBACKGROUND.The objective of the current study was to evaluate the outcome of a surveillance strategy in patients with renal masses.METHODS.The medical records of patients with renal masses diagnosed between January 1992 and May 2006 were reviewed retrospectively. In all, 45 patients with renal masses under observation were identified. Of these, 35 patients with 44 renal masses measuring <4 cm in dimension at the time of diagnosis and who were followed for at least 6 months were included in the review. Patients elected observation because of age, comorbidity, solitary kidney, or bilateral renal masses. Medical records were reviewed to determine tumor size and volume changes as well as clinical progression requiring treatment, the development of metastatic disease, or death.RESULTS.A total of 35 patients (21 men and 14 women) with 44 renal masses were observed for a mean follow‐up of 47.6 months. The mean age of these patients was 71.8 years. The majority of the patients (89%) were asymptomatic at the time of diagnosis. The mean and median initial tumor dimension was 2.2 cm and 2.2 cm, respectively (range, 0.5–4 cm). Of the 35 patients, 2 (5.7%) were lost to follow‐up, 8 (22.9%) underwent surgical resection, and 9 (25.7%) died of other causes. The mean dimension growth rate was 0.21 cm/year (range, 0.03–1.9 cm/year). The mean and median volume growth rate was 2.7 cc/year and 1.4 cc/year, respectively. Progression to metastatic disease was identified in 2 patients (5.7%).CONCLUSIONS.The majority of renal masses will grow if observed and some may require treatment. Initial tumor size cannot predict the natural history of renal masses. A small but non‐negligible risk of developing metastatic disease exists in this patient population. Further research should focus on the role of biopsy and on identification of prognostic parameters allowing more accurate prediction of tumor growth and metastasis. Cancer 2007. © 2007 American Cancer Society.
Single DNA Molecule Isolation and Trapping in a Microfluidic Device
Authors: Kumemura Momoko , Collard Dominique , Yamahata Christophe , Sakaki Naoyoshi , Hashiguchi Gen , Fujita Hiroyuki 
Published: July 2007

AbstractThis paper presents a systematic method to isolate and trap long single DNA segments between integrated electrodes in a microfluidic environment. Double stranded λ‐DNA molecules are introduced in a microchip and are isolated by electrophoretic force through microfluidic channels. Downstream, each individual molecule is extended and oriented by ac dielectrophoresis (900 kHz, 1 MV m−1) and anchored between aluminium electrodes. With a proper design, a long DNA segment (up to 10 μm) can be instantly captured in stretched conformation, opening way for further assays.
A reinforced movable boundary multiplexing scheme with adaptive interpolation: Modelling and performance evaluation
Authors: Meempat Gopalakrishnan , Sundareshan Malur K. 
Published: July 2007

AbstractA novel multiplexing scheme for integrated networks characterized by the coexistence of circuitswitched and packet‐switched traffic is described in this paper. The new scheme is realized by a reinforcement of the basic movable boundary hybrid‐switching technique, by incorporating an adaptive interpolation within the circuit‐switched subsystem. The adaptation mechanism is controlled by the level of congestion in the packet queue. A precise queueing model for the multiplexer is developed and an analytical evaluation of the key performance parameters of interest, namely the loss probability and expected delay of the packet‐switched subsystem, and the freeze‐out fraction of the circuit‐switched subsystem, is conducted. The results of several numerical studies are presented to describe the performance of the multiplexer under different conditions. Of particular significance resulting from these studies is the trade‐off between the freeze‐out fraction of the circuit‐switched subsystem and the loss probability of the packet‐switched subsystem; this trade‐off may be exploited in a systematic design of the interrated multiplexer tailored to specific applications.
A multilevel framework for the attribute description of telecommunication services
Authors: de Smedt Alex , Hellemans Patrick , Roncheiti Luigi , Täubig Klaus 
Published: July 2007

AbstractTelecommunication services are traditionally described from the terminal viewpoint, including the user interaction with the service, as well as the specific terminal characteristics to the network that it is meant for. Also traditionally the instance of the telecommunication service was a call and a connection as a one‐to‐one couple.Nowadays networks with powerful multimedia/multiconnection/multiparty capabilities require that a telecommunication service should not be described any more as a conglomerate, but by its main service elements, which in turn are supported by other service elements, so that a service may be built up by building blocks in a levelled model.The criteria to be considered to find these elements are the user viewpoint, the information coding (or terminal) viewpoint and the network access viewpoint. This leads to the telecommunication service, party, party edge, user service module and abstract service module as pure user‐dependent service elements, the service module for the terminal aspect, and the access connection element for transfer of the information over the network.All these basic service elements are ordered in a levelled structure called a multilevel framework. Each level or co‐level represents a service element type which may be instantiated as a service object, and which is described statically by a table of attributes. Attributes for each level are listed and clarified.An example describing a well‐known service is given to illustrate the use of the framework.The views expressed in this document have been developed by the RACE 2044 MAGIC.RACE: Research into Advanced Communication Technologies for Europe. MAGIC: Multi‐service Applications Governing Integrated Control.
The concepts presented are related to Release 2 and 3 for BISDN as defined in ITU‐T.
Equivalent bandwidth and related admission criteria for ATM systems—a performance study
Authors: Rege Kiran M. 
Published: July 2007

AbstractThe concept of the equivalent bandwidth of a source seems highly attractive for characterizing ATM traffic sources as it can be used to treat constant as well as variable bit rate sources within a common framework. In this paper we review the concept of equivalent bandwidth based on asymptotic results and study the performance of a few admission criteria which use this concept in one way or another. A major finding is that with appropriate refinements to account for the possible statistical multiplexing gain at small to moderate buffer sizes, the well‐known conservatism of the asymptotic equivalent bandwidth based criteria can be overcome. We also discuss how these criteria would perform in practical situations where the traffic sources are incompletely characterized, or where they are specified in terms of leaky‐bucket based traffic descriptors.
Output‐queue contents in a ‘minislot’ synchronized ATM switch
Authors: Xiong Yijun , Bruneel Herwig 
Published: July 2007

AbstractAnN × Nswitching element with output queueing, as used in a large ATM switching network, is considered. All the inlets of the switching element are synchronized on ‘minislots’, where a minislot is the fixed‐length time unit for the transmission of one ‘minicell’. When entering the switching network, an ATM cell is converted into a ‘minicell‐train’, consisting of a fixed number of minicells. Using an active/silent model, it is assumed that on each inlet of the switching element, the number of minicelltrains in an active period and the length of a silent period are both geometrically distributed, and the arriving minicell‐trains are uniformly distributed among all the outlets. The performance of the switching element can be obtained by analysing one single output queue, which is modeled as a discrete‐time single‐server queuing system with train arrivals. In this paper, an upper bound and an approximate expression for the mean queue length are derived. More importantly, an analytical method is developed to obtain a tight upper bound and a good approximation for the tail distribution of the queue length. This analytical method is very useful in buffer dimensioning of ATM switches.
Proportional rate‐based congestion control under long propagation delay
Authors: Cavendish Dirceu , Oie Yuji , Murata Masayuki , Miyahara Hideo 
Published: July 2007

AbstractThe occurrence of congestion severely degrades the performance, especially in high‐speed networks with long propagation delay relative to packet transmission time. This is because it is very likely that a large number of transit packets are flying over such networks at a time and many of them will get lost if they arrive at some congested node. Among ways of controlling traffic to avoid congestion, this paper deals with a class of rate‐based congestion controls (RBCC) which regulate input traffic based on feedback information about network congestion status. Although such mechanisms have been studied recently, the mechanism to be considered, referred to asproportionalRBCC, differs from them in that the amount of input traffic allowed to enter in the network isproportionalto the network resources available, keeping a closer track of the network resources than the previous ones, where the network status is described by two states, congested or not. The mechanism seeks an optimal network operating point, adapting to dynamic changes of carried traffic. We carry out the stability analysis and the transient analysis of some performance measures related to the proportional RBCC, and also address fairness aspects in providing control to various source‐destination connections, while K. W. Fendicket al.have analysed the stability of a general class of RBCC. Furthermore, by making a comparison between the control mechanism analysed here and the ones based on binary feedback information, we show the effectiveness of the former.
Deterministic rule based traffic descriptors for broadband ISDN: Worst case behaviour and its impact on connection acceptance controls
Authors: Doshi B. T. 
Published: July 2007

AbstractDeterministic rule based traffic descriptors in general, and leaky bucket based (LBB) traffic descriptors in particular, offer many advantages over statistical descriptors for specifying and monitoring traffic in the ATM based broadband ISDN (BISDN). However, these traffic descriptors do not specify the traffic pattern uniquely. Thus, acceptance of a connection request with specific traffic descriptor parameter values implies that the network has agreed to guaranteeing the quality of service (QOS) for the worst case traffic compliant with the traffic descriptor (and hence allowed by the monitor). This poses challenges which have not been addressed adequately. Two of the important ones are: (i) definition of the worst case behaviour and characterization of the worst case traffic compliant with the traffic descriptor; (ii) connection acceptance controls (CAC) for the worst case traffic sources compliant with the traffic descriptors. In this paper we address these questions for leaky bucket based (LBB) traffic descriptors. The focus is on the first problem. The implications on the second problem are discussed briefly. The performance measure and QOS requirements are in terms of the cell loss ratios.We first define the worst case behaviour for homogeneous and heterogeneous environments in terms of collective cell loss ratio (CLR)) from the multiplexer. We consider both the unbuffered and buffered cases. However, most of the results here are for the unbuffered case. FOTthe case of an unbuffered multiplexer and homogeneous source environment, we show that a simple on‐off source represents the worst case behaviour of an LBB source. In a heterogeneous source traffic environment, the on‐off behaviour is the worst only in a limited sense and the use of a collective measure results in anomalous relationships between the source behaviour and the CLR. A more appropriate measure should be based on individual cell loss ratios or on the maximum of the individual CLRs. We analyse LBB sources with respect to these measures and unbuffered resources, and obtain further characterization of the worst case behaviour. However, we also uncover some counter‐intuitive relationships. In particular, a seemingly ‘smooth’ source may be worse for the other sources than a seemingly ‘bursty’ source.For a buffered multiplexer, we show, via an example, that a three‐state source may be worse than an on‐off source even in a homogeneous source traffic environment. A complete characterization of the worst case behaviour for a buffered multiplexer remains an open challenge. Moreover, the LBB sources exhibit deterministic behaviour and their equivalent bandwidth need not be sub‐additive in sources. That is, adding the equivalent bandwidths of individual sources to obtain an ‘estimate’ of the equivalent bandwidth for a collection of such sources could be too optimistic in some situations. A fresh look at the connection acceptance control for such sources is therefore warranted.
Comparison of admission control schemes in ATM networks
Authors: Causey Jeffrey W. , Kim Hyong S. 
Published: July 2007

AbstractAsynchronous transfer mode (ATM) offers an efficient means of carrying a wide spectrum of BISDN traffic provided that network congestion is prevented. Unfortunately, efficient congestion control is difficult to achieve in integrated broadband networks, owing to the wide range of traffic characteristics and quality of service (QOS) requirements. We have implemented a network simulator that allows us to evaluate many proposed admission control schemes using many different traffic models. We present the results of several simulation studies, including one study of the performance of the admission control schemes in the presence of traffic sources that exhibit long‐term dependence.
Shared buffer ATM switch with doubly linked lists
Authors: Lin Yeong‐Fong , Shung C. Bernard 
Published: July 2007

AbstractThe Shared buffer memory switch (SBMS) architecture was originally proposed as an effective approach to implement ATM switch fabrics. However, in this paper we find that if an error occurs in the address chain memory of one linked list which stores the address of the next cell in the shared buffer memory, the erroneous situation will spread over all linked lists in the SBMS in a short time. In order to prevent the fault spread phenomenon, we propose two doubly linked list based architectures to combat address chain failure; these are referred to as the Flush and In‐Seq schemes. The first scheme flushes the remaining cells in the faulty queue but collect their addresses for later usage. The second scheme outputs the remaining cells in their correct sequence. From our simulation, if the error injection rate is low, the performance of the In‐Seq scheme experiences slight degradation compared with the errorfree situation.
An algorithm for sizing trunks carrying mixtures of constant and variable bit rate traffic
Authors: Rege Kiran M. 
Published: July 2007

AbstractAs new broadband networks based on the asynchronous transfer mode (ATM) protocol emerge to support a variety of services, the need for analytical models and tools for sizing network components carrying mixtures of different kinds of traffic will be increasingly felt. This paper presents a simple, yet efficient algorithm for sizing trunks carrying mixtures of constant and variable bit rate traffic. It combines theoretical results for the multi‐dimensional Erlang model and the concept of equivalent bandwidth with some heuristic arguments to produce an analytic method for sizing trunks subject to blocking and quality of service constraints for traffic classes.
Distortionless theory of one‐dimensional non‐uniform transmission lines
Authors: Ito Chiaka , Sato Risaburo 
Published: July 2007

AbstractFor transmitting distortionless arbitrary waveforms over set‐ups with different impedances, the nonuniform lines have been used for a long time by wide‐band impedance‐transform and matching. But rigorous theory is still lacking in treating the basic problems concerning the relationship between the distortionless waveform and the nonuniform line distribution, i.e., the distortionless conditions or the impedance‐matching conditions for the nonuniform lines. This paper first investigates the voltage/current transfer‐functions over any line interval and the local propagation constant. It is then clarified that there exist on the one‐dimensional nonuniform line essentially six localized distortionless conditions for the voltage/current waveforms. Next, the distortionless wave quantities and characteristics, the finitely long line analysis, as well as method of excitation (matching) of the distortionless wave, are presented. Finally, it is shown that all‐pass impedance transformer, attenuator and phase shifter can be realized by using the distortionless line.
Alpha‐particle‐induced soft errors in high speed bipolar ram
Authors: Mitsusada Kazumichi , Katos Yukio , Yamaguchi Kunihiko , Inadachis Masasaki 
Published: July 2007

AbstractSoft errors of the bipolar RAM (Random Access Memory) caused by α particles emitted from the radioactive material in the package are investigated. The in‐system test and the particle irradiation test were performed by using a 1 Kbit RAM made especially for this purpose. The relation between the soft error rate and the amount of the α particle irradiation was examined. It was confirmed that even in the static bipolar RAM, soft errors do occur due to α particles from the package. The relation between the soft error rate, memory cell structure and the design condition was discussed. Furthermore, the mechanism of soft errors was investigated and the soft error rate was estimated by considering the effective noise change due to α particles and the charge required to invert data in the flip‐flop cell. These results were compared with the experiment.
A model of failure propagation process
Authors: Kokawa Masasumi , Shioya Makoto , Ohnari Mikihiko 
Published: July 2007

AbstractWith the development of towns, various systems, such as chemical plants, water supply and sewage systems, are growing in size and complexity. Therefore, once a failure occurs at one part of a system, its influence spreads extensively to large peripheral areas. Therefore, the key problem is how to protect the systems against the failure propagation to maintain the system safety and reliability. However, the preventive maintenance design or prearranged measures are hard to prepare due to insufficient analysis of the failure propagation process in complicated systems.This paper proposes a method of building a model of failure propagation process structurally and quantitatively to help in designing preventive maintenance. This method consists in a failure propagation network based on the failure propagation linkages between a failure element and its adjacent failure elements in the system. In addition, it permits the failure propagation simulation, function survival route search, and assessment of risks caused by the failure propagation, with the help of failure transition probability and matrix operation.