bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of node switching capabilities on the performance of wavelength routed networks
Authors: Andriolli Nicola , Valcarenghi Luca , Castoldi Piero 
Published: April 2005

AbstractPerformance of wavelength routed optical networks (WRONs), which consist of circuit switched all‐optical connections, namely lightpaths, heavily depends on network node capabilities. Advanced network node switching capabilities might improve WRON performance but they often imply an increase in node cost. In this paper, we evaluate the performance benefits brought by the introduction of selected capabilities in the WRON node architecture. In particular, we consider the WRON performance dependence on the (i) wavelength selection and (ii) wavelength conversion capabilities and (iii) on the number of available transponders at the tributary side. For this purpose, we propose and utilise a modified version of the shortest path algorithm for the wavelength graph (SPAWG). The modified SPAWG utilises a graph in which ‘virtual hops’ are added for modelling the utilisation and the cost of specific node capabilities. Numerical results show the performance advantages in utilising wavelength selection instead of wavelength conversion, when only one of the two capabilities can be implemented in each network node. When wavelength conversion and wavelength selection utilisation is limited to a subset of network nodes to reduce the overall network cost, results indicate that sparse wavelength selection is not as beneficial as sparse wavelength conversion. In addition, a limitation on the number of transponders at the tributary side slightly affects network performance. Copyright © 2005 AEIT.
Performance analysis of TH‐UWB radio systems using proper waveform design in the presence of narrow‐band interference
Authors: Khani Hassan , Azmi Paeiz 
Published: April 2005

AbstractUltra‐wide band (UWB) radio systems, because of their huge bandwidth, must coexist with many narrow‐band systems in their frequency band. This coexistence may cause significant degradation in the performance of both kinds of systems. Currently, several methods exist for narrow‐band interference (NBI) suppression in UWB radio systems. One of them is based on mitigating the effects of NBI through proper waveform design. In Reference 1, it has been shown that using properly designed doublet waveform can significantly reduce the effects of NBI on an important kind of UWB radio systems, i.e. BPSK time‐hopping UWB (TH‐UWB) systems. In this paper, the proper waveform design technique is extended to BPPM TH‐UWB systems. It is shown that this method can properly suppress the effects of NBI on the performance of BPPM TH‐UWB systems. Copyright © 2005 AEIT.
Neuroprotective role of astrocytes in cerebral ischemia: Focus on ischemic preconditioning
Authors: Trendelenburg George , Dirnagl Ulrich 
Published: April 2005

AbstractFollowing focal cerebral ischemia (“stroke”) a complex and dynamic interaction of vascular cells, glial cells, and neurons determines the extent of the ensuing lesion. Traditionally, the focus has been on mechanisms of damage, while recently it has become clear that endogenous mechanisms of protection are equally important for the final outcome. Glial cells, in particular astrocytes, have always been viewed as supporters of neuronal function. Only recently a very active role for glial cells has been emerging in physiology and pathophysiology. Not surprisingly, then, specific protective pathways have been identified by which these cells can protect or even help to regenerate brain tissue after acute insults. However, as exemplified by the existence of the glial scar, which forms around lesioned brain tissue, is composed mainly of astrocytes and plays a key role in regeneration failure, it is an oversimplification to assign merely protective functions to astrocytes. The present review will discuss the role of astrocytes in ischemic brain injury with a focus on neuroprotection in general. In this context we will consider particularly the phenomenon of “ischemic tolerance,” which is an experimental paradigm helpful in discriminating destructive from protective mechanisms after cerebral ischemia. © 2005 Wiley‐Liss, Inc.
Identification of oligodendrocytes in experimental disease models
Authors: Ness Jennifer K. , Valentino Mario , McIver Sally R. , Goldberg Mark P. 
Published: April 2005

AbstractThe ability to identify oligodendrocytes in culture, in fixed tissue, and in vivo using unique markers is a requisite step to understanding their responses in any damage, recovery, or developmental process. Their nuclei are readily seen in histological preparations of healthy white and gray matter, and their cell bodies can be reliably identified with a variety of immunocytochemical markers. However, there is little consensus regarding optimal methods to assess oligodendrocyte survival or morphology under experimental injury conditions. We review common approaches for histological and immunocytochemical identification of these cells. Transgenic and viral methods for cell type‐selective transfer of genes encoding fluorescent proteins offer promising new approaches for manipulating and visualizing oligodendrocytes in models of health and disease. © 2005 Wiley‐Liss, Inc.
N‐back working memory paradigm: A meta‐analysis of normative functional neuroimaging studies
Authors: Owen Adrian M. , McMillan Kathryn M. , Laird Angela R. , Bullmore Ed 
Published: April 2005

AbstractOne of the most popular experimental paradigms for functional neuroimaging studies of working memory has been the n‐back task, in which subjects are asked to monitor the identity or location of a series of verbal or nonverbal stimuli and to indicate when the currently presented stimulus is the same as the one presented n trials previously. We conducted a quantitative meta‐analysis of 668 sets of activation coordinates in Talairach space reported in 24 primary studies of n‐back task variants manipulating process (location vs. identity monitoring) and content (verbal or nonverbal) of working memory. We found the following cortical regions were activated robustly (voxelwise false discovery rate = 1%): lateral premotor cortex; dorsal cingulate and medial premotor cortex; dorsolateral and ventrolateral prefrontal cortex; frontal poles; and medial and lateral posterior parietal cortex. Subsidiary meta‐analyses based on appropriate subsets of the primary data demonstrated broadly similar activation patterns for identity monitoring of verbal stimuli and both location and identity monitoring of nonverbal stimuli. There was also some evidence for distinct frontoparietal activation patterns in response to different task variants. The functional specializations of each of the major cortical components in the generic large‐scale frontoparietal system are discussed. We conclude that quantitative meta‐analysis can be a powerful tool for combining results of multiple primary studies reported in Talairach space. Here, it provides evidence both for broadly consistent activation of frontal and parietal cortical regions by various versions of the n‐back working memory paradigm, and for process‐ and content‐specific frontoparietal activation by working memory. Hum Brain Mapp 25:46–59, 2005. © 2005 Wiley‐Liss, Inc.
Automated analysis of meta‐analysis networks
Authors: Lancaster Jack L. , Laird Angela R. , Fox P. Mickle , Glahn David E. , Fox Peter T. 
Published: April 2005

AbstractThe high information content in large data sets from voxel‐based meta‐analyses is complex, making it hard to readily resolve details. Using the meta‐analysis network as a standardized data structure, network analysis algorithms can examine complex interrelationships and resolve hidden details. Two new network analysis algorithms have been adapted for use with meta‐analysis networks. The first, called replicator dynamics network analysis (RDNA), analyzes co‐occurrence of activations, whereas the second, called fractional similarity network analysis (FSNA), uses binary pattern matching to form similarity subnets. These two network analysis methods were evaluated using data from activation likelihood estimation (ALE)‐based meta‐analysis of the Stroop paradigm. Two versions of these data were evaluated, one using a more strict ALE threshold (P < 0.01) with a 13‐node meta‐analysis network, and the other a more lax threshold (P < 0.05) with a 22‐node network. Java‐based applications were developed for both RDNA and FSNA. The RDNA algorithm was modified to provide multiple subnets or maximal cliques for meta‐analysis networks. Three different similarity measures were evaluated with FSNA to form subsets of nodes and experiments. RDNA provides a means to gauge importance of metanalysis subnets and complements FSNA, which provides a more comprehensive assessment of node similarity subsets, experiment similarity subsets, and overall node‐to‐factors similarity. The need to use both presence and absence of activations was an important finding in similarity analyses. FSNA revealed details from the pooled Stroop meta‐analysis that would otherwise require separate highly filtered meta‐analyses. These new analysis tools demonstrate how network analysis strategies can simplify greatly and enhance voxel‐based meta‐analyses. Hum Brain Mapp 25:174–184, 2005. © 2005 Wiley‐Liss, Inc.
A New Crystal Form, Polymorphism, and Multi‐Morphology in Biodegradable Poly(3‐hydroxypropionate)
Authors: Zhu Bo , He Yong , Asakawa Naoki , Yoshie Naoko , Nishida Haruo , Inoue Yoshio 
Published: April 2005

AbstractSummary: A new crystal morphology (δ form) of poly(3‐hydroxypropionate) (PHP) is found in cast and melt‐crystallized PHPs with low molecular weight, in which the PHP chains possibly adopt a 21 helix rather than the trans conformation found in the β or γ form. The fusion temperature‐ and the crystallization temperature‐dependent polymorphism are responsible for the dual morphologies and the unique growth kinetics of spherulites in the melt‐crystallized PHPs.a) A dual‐morphology developed at 70 °C in PHP films after melting at 117 °C and b) that formed during cooling at a rate of 1 °C · min−1 from 130 °C.magnified imagea) A dual‐morphology developed at 70 °C in PHP films after melting at 117 °C and b) that formed during cooling at a rate of 1 °C · min−1 from 130 °C.
Novel Hole‐Transport Material for Efficient Polymer Light‐Emitting Diodes by Photoreaction
Authors: Kimoto Atsushi , Cho Jun‐Sang , Ito Kiyoshi , Aoki Daigo , Miyake Tohru , Yamamoto Kimihisa 
Published: April 2005

AbstractSummary: The photo‐crosslinking of carbazole dendrimers was analyzed by UV and IR spectroscopic methods. Photoirradiation results in the formation of a film that is insoluble in toluene and benzene. Time‐of‐flight mass spectrometry studies revealed that the photoirradiation lead to an oligomerization of the dendrimer through crosslinking. The resulting insoluble dendrimer film could be applied as a hole‐transport layer in efficient polymer electroluminescence devices (PLEDs).Luminance‐voltage characteristics for PLEDs wherein PEDOT:PSS and CbzG3 complex with SnCl2 were employed as the hole transport layer (ITO/HTL/EML/Ca/Ag).magnified imageLuminance‐voltage characteristics for PLEDs wherein PEDOT:PSS and CbzG3 complex with SnCl2 were employed as the hole transport layer (ITO/HTL/EML/Ca/Ag).
Evidence for lymphangiogenesis and its prognostic implications in head and neck squamous cell carcinoma
Authors: Kyzas Panayiotis A , Geleff Silvana , Batistatou Anna , Agnantis Niki J , Stefanou Dimitrios 
Published: April 2005

AbstractLymph node metastasis is a frequent reason for adverse clinical outcome in many epithelial neoplasms, including head and neck squamous cell carcinoma. The mechanisms underlying the capability of epithelial neoplasms to metastasize via lymphatic vessels have not yet been fully elucidated. There is great debate about whether cancer cells can metastasize by expansion and invasion of pre‐existing peritumoral lymphatics or by the formation and invasion of new lymphatics within tumours (lymphangiogenesis). In order to investigate this issue, we examined 81 tissue specimens from patients with head and neck squamous cell carcinoma, using immunostaining for the specific lymphatic endothelium marker podoplanin, and assessed intratumoral and peritumoral lymphatic density. We also quantified lymphatic invasion and examined the possible associations of all the above parameters with clinicopathological features and outcome. Finally, we used double staining with podoplanin and the cell proliferation marker Ki‐67 in order to evaluate lymphangiogenesis. High intratumoral and peritumoral lymphatic density were both significantly associated with the presence of lymph node metastasis at the time of diagnosis (χ2 test, p < 0.001 and p = 0.007, respectively) and there was a significant correlation between high intratumoral lymphatic density and lymphatic invasion. Patients with higher intratumoral lymphatic density exhibited shorter overall survival (log rank p < 0.001) and this correlation remained significant after multivariate analysis (Cox p = 0.04), indicating that intratumoral lymphatic density is an independent prognostic factor for mortality. Peritumoral lymphatic density had no influence on outcome. Double staining revealed the existence of proliferating intratumoral lymphatics, in which tumour emboli were occasionally observed. These results indicate that lymphangiogenesis indeed occurs in head and neck squamous cell carcinoma; that newly formed vessels are targets of invasion by cancer cells; and that intratumoral lymphatic density might be used as a criterion to separate patients at higher risk of an adverse clinical outcome. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Predicting the Detonation Velocity of CHNO Explosives by a Simple Method
Authors: Keshavarz Mohammad Hossein , Pouretedal Hamid Reza 
Published: April 2005

AbstractA simplified method is shown, based on a semi‐empirical procedure, to estimate the detonation velocities of CHNO explosives at various loading densities. It is assumed that the product composition consists almost of CO, CO2, H2O and N2 for oxygen‐rich explosives. In addition solid carbon and H2 are also counted for an oxygen‐lean explosive. The approximate detonation temperature, as a second needed parameter, can be calculated from the total heat capacity of the detonation products and the heat of formation of the explosive by PM3 procedure. The detonation velocities of some well‐known CHNO explosives, calculated by the simple procedure, fit well with measured detonation velocities and the results from the well‐established BKW‐EOS computer code.
Adaptive admission/congestion control policies for CDMA‐based wireless internet
Authors: Baroudi U. A. , Elhakeem A. K. 
Published: April 2005

AbstractRadio resource management (RRM) is vital for the next generation wireless networks. RRM comprises many functionalities and this paper focuses on the investigation of the performance of several adaptive call admission/congestion control policies based on a window‐measurement estimation of the status of the buffer at the base station under the hybrid TDMA/CDMA access scheme. In our study, we interrelate the physical limitations of the base stations (i.e. the number of transmission and reception modems), call and burst level traffic, instantaneous buffer conditions and end‐to‐end bit error performance in one queuing problem. Subsequently, a window‐measurement estimator is implemented to estimate the likelihood of buffer congestion at the base station. Accordingly, the traffic loads shall be controlled. We use event‐driven simulation to simulate the multimedia integrated CDMA networks where heterogeneous traffic users are multiplexed into a simple TDMA frames. The simulation results show outstanding performance of the proposed call admission/congestion control policies in guaranteeing QoS requirements. Copyright © 2005 John Wiley & Sons, Ltd.
A mobile service platform using proxy technology
Authors: Chen Ming‐Feng , Lin Yi‐Bing , Rao Herman C.‐H. , Wu Quincy 
Published: April 2005

AbstractThis paper proposes iMobile, a proxy‐based platform for developing mobile services for various mobile devices and wireless access technologies. iMobile acts as a message gateway that allows mobile devices to relay messages to each other through various protocols on different access networks. It allows mobile devices to access internet services, corporate databases and to control various network devices. iMobile implements three key abstractions: dev‐let, info‐let and app‐let. An info‐let provides abstract view of information space. An app‐let implements service or application logic by processing information from various info‐lets. A dev‐let receives and sends messages through any particular protocols for mobile devices. The let engine supports user and device profiles for personalization and transcoding, and invokes proper app‐lets and info‐lets to answer requests from a dev‐let. The iMobile modular architecture allows developers to write device drivers, information access methods and application logic independently from each other. Copyright © 2005 John Wiley & Sons, Ltd.
Efficient broadcasting protocols for regular wireless sensor networks
Authors: Sheu Jang‐Ping , Hsu Chih‐Shun , Chang Yen‐Jung 
Published: April 2005

AbstractThe wireless sensor network (WSN) has attracted lots of attention recently. Broadcast is a fundamental operation for all kinds of networks and it has not been addressed seriously in the WSN. Therefore, we propose two types of power and time efficient broadcasting protocols, namely one‐to‐all and all‐to‐all broadcasting protocols, for five different WSN topologies. Our one‐to‐all broadcasting protocols conserve power and time by choosing as few relay nodes as possible to scatter packets to the whole network. Besides, collisions are carefully handled such that our one‐to‐all broadcasting protocols can achieve 100% reachability. By assigning each node a proper channel, our all‐to‐all broadcasting protocols are collision free and efficient. Numerical evaluation results compare the performance of the five topologies and show that our broadcasting protocols are power and time efficient. Copyright © 2005 John Wiley & Sons, Ltd.
Determination of the multi‐slot transmission in Bluetooth systems with the estimation of the channel error probability
Authors: Sung Ki Won , Lee Chae Y. 
Published: April 2005

AbstractBluetooth is an open specification for a technology to enable short‐range wireless communications that operate in an ad hoc fashion. Bluetooth uses frequency hopping with a slot length of 625 μs. Each slot corresponds to a packet and multi‐slot packets of three or five slots can be transmitted to enhance the transmission efficiency. However, the use of multi‐slot packet may degrade the transmission performance under high channel error probability. Thus, the length of multi‐slot should be adjusted according to the current channel condition. Segmentation and reassembly (SAR) operation of Bluetooth enables the adjustment of the length of multi‐slot. In this paper, we propose an efficient multi‐slot transmission scheme that adaptively determines the optimal length of slots of a packet according to the channel error probability. We first discuss the throughput of a Bluetooth connection as a function of the length of a multi‐slot and the channel error probability. A decision criteria which gives the optimal length of the multi‐slot is presented under the assumption that the channel error probability is known. For the implementation in the real Bluetooth system, the channel error probability is estimated with the maximum likelihood estimator (MLE). A simple decision rule for the optimal multi‐slot length is developed to maximize the throughput. Simulation experiment shows that the proposed decision rule for the multi‐slot transmission effectively provides the maximum throughput under any type of channel error correlation. Copyright © 2005 John Wiley & Sons, Ltd.
Call admission control in mobile cellular networks: a comprehensive survey
Authors: Ghaderi Majid , Boutaba Raouf 
Published: April 2005

AbstractCall admission control (CAC) is a key element in the provision of guaranteed quality of service (QoS) in wireless networks. The design of CAC algorithms for mobile cellular networks is especially challenging given the limited and highly variable resources, and the mobility of users encountered in such networks. This article provides a survey of admission control schemes for cellular networks and the research in this area. Our goal is to provide a broad classification and thorough discussion of existing CAC schemes. We classify these schemes based on factors such as deterministic/stochastic guarantees, distributed/local control and adaptivity to traffic conditions. In addition to this, we present some modeling and analysis basics to help in better understanding the performance and efficiency of admission control schemes in cellular networks. We describe several admission control schemes and compare them in terms of performance and complexity. Handoff prioritization is the common characteristic of these schemes. We survey different approaches proposed for achieving handoff prioritization with a focus on reservation schemes. Moreover, optimal and near‐optimal reservation schemes are presented and discussed. Also, we overview other important schemes such as those designed for multi‐service networks and hierarchical systems as well as complete knowledge schemes and those using pricing for CAC. Finally, the paper concludes on the state of current research and points out some of the key issues that need to be addressed in the context of CAC for future cellular networks. Copyright © 2005 John Wiley & Sons, Ltd.
Diagnosis of primary and secondary hyperparathyroidism
Authors: Roeher H. D. , Schmidt‐Gayk H. 
Published: April 2005

AbstractRoutine application of multichannel laboratory screening for both inpatients and outpatients has increased detection of hypercalcemia. With these improved diagnostic tools, it has become possible to distinguish true hyperparathyroidism from nonendocrine disorders of calcium metabolism. Typical features of primary and secondary hyperparathyroidism are described in relation to their clinical presentation. Diagnosis is based on laboratory findings which include repeated serum calcium and phosphate measurements as the first step, additional specific functional tests for borderline cases, and serum parathyroid hormone (PTH) measurements as pathognomonic proof of excess hormone secretion. Significance and reliability of diagnostic procedures are discussed with regard to routine and selective application.
Hyperparathyroidism with asymptomatic hypercalcemia and symptomatic normocalcemia
Authors: Thorén Lars 
Published: April 2005

AbstractAsymptomatic hyperparathyroidism has been found with increasing frequency as serum calcium determinations have become routine. Normocalcemic hyperparathyroidism has been diagnosed in patients who have recurrent urinary tract stones in combination with hypercalciuria.The indications for surgery in asymptomatic hyperparathyroidism are difficult to evaluate. Three treatment options for dealing with verified asymptomatic hyperparathyroidism are discussed. The option of neck exploration is advocated for the purpose of preventing the complications of renal impairment, persistent hypertension, and skeletal disease.The presence of urinary tract stones is the main reason for suspecting normocalcemic hyperparathyroidism. Although various tests can be used, the final diagnosis is often made at neck exploration. The recurrence of urinary tract stones and the possibility of kidney damage are the main reasons for surgery. Further study is needed to evaluate fully the results of parathyroid surgery in normocalcemic hyperparathyroidism.