bluuebunny/crossref_metadata_2025 huggingface dataset:
QOS and call admission control of multimedia traffic in a PCS network
Authors: Lee Duan‐Shin , Chen Chun‐Chia
Published: August 2004

In this paper we study the quality of service of integrated voice and data services in a wireless network. The voice traffic is transmitted in circuit‐switched mode and data traffic is transmitted in packet‐switched mode. Voice traffic has high transmission priority and data packets are transmitted only when there are available channels not used by the voice traffic. Otherwise, the data packets wait in a data buffer. We consider two schemes to reduce the forced termination probability for the handoff voice calls. The two schemes are the reserved channel scheme and the queueing priority scheme. We apply a fluid analysis to study the performance of the data buffer under the two handoff schemes and the basic system in which there is no arrangement to reduce the forced termination probability of handoff calls. From this analysis, we derive admission controls for voice traffic as well as for data traffic. This analysis also enables us to conclude that the reserved channel scheme not only is more effective in reducing the forced termination probability of handoff calls, it is also more effective in providing the QOS guarantee for the data traffic. Another contribution of this paper is to develop a perturbation analysis to solve the fluid models efficiently and quickly. Copyright © 2004 John Wiley & Sons, Ltd.
The study of handoff prediction schemes for resource reservation in mobile multimedia wireless networks
Authors: Lu Li‐Liann , Wu Jean‐Lien C. , Chen Wei‐Yeh
Published: August 2004

In this paper, the mobility‐dependent predictive resource reservation (MDPRR) scheme is proposed to provide flexible usage of scarce resource in mobile multimedia wireless networks. An admission control scheme is also considered to further guarantee the QoS of real‐time traffic. The area of a cell is divided into non‐handoff, pre‐handoff, and handoff zones so that bandwidth is reserved in the target/sub‐target cell as mobile stations move into the pre‐handoff zone and leave the serving base station. The amount of bandwidth to be reserved is dynamically adjusted according to the location, the instantaneous variation of velocity and direction of mobile stations. Two scenarios of the MDPRR scheme are compared by considering the velocity threshold in the calculation of the weight of direction. A number of designs are investigated to further enhance the performance of the proposed scheme. The results show that employing the velocity threshold in the MDPRR scheme can indeed reduce connection dropping probability, and make better usage of the reserved bandwidth. Copyright © 2004 John Wiley & Sons, Ltd.
A multi‐service link layer architecture for the wireless Internet
Authors: Xylomenos George , Polyzos George C.
Published: August 2004

The performance of Internet applications over wireless links is disappointing due to the adverse effects of wireless errors on higher layer protocols and applications. This paper focuses on link layer enhancement mechanisms which attempt to hide these wireless impairments. We simulate file transfer and WWW browsing over TCP and continuous media distribution over UDP, in conjunction with various link layer schemes. Our results reveal that WWW browsing behaves differently than bulk file transfer, that some TCP aware enhancements have limited applicability and that UDP applications are best served by schemes inappropriate for TCP. We then describe a multi‐service link layer architecture that simultaneously enhances the performance of diverse applications by supporting multiple error recovery schemes in parallel. In order to evaluate our architecture, we repeat our previous simulations with all applications executing simultaneously. The results reveal that with our approach each application achieves similar improvements as when it operates alone over its preferred link layer. Copyright © 2004 John Wiley & Sons, Ltd.
Capacity optimizing channel allocation schemes for multi‐service cellular systems
Authors: Yang Ming , Chong Peter H. J.
Published: August 2004

The trend of the wireless communication system is to provide various types of services such as voice, data and video etc. Due to the limited radio resources with international agreement, how to achieve the optimum system capacity becomes a paramount issue. In this paper, we use the idea of channel partitioning (CP) employing different reuse factors to support multiple services that require different signal‐to‐interference ratios (SIRs) in cellular systems. Two types of services are considered in this paper. Thus, we use a large reuse factor to support high SIR required service while we use a small reuse factor to support low SIR required service. From the system point of view, the average reuse factor becomes smaller and the system capacity can be improved. The system performance of CP with fixed channel allocation (FCA) scheme, namely fixed channel partitioning (FCP), is first proposed and analysed using Markov chain in a single cell model. Then a dynamic channel allocation scheme with CP called dynamic channel partitioning with interference information (DCP‐WI) is proposed and studied in the multiple‐cell model by computer simulation. The analysis and simulation results show that our proposed schemes can improve the system capacity depending on the traffic load fraction for each service. For equal arrival rate for both services, FCP and DCP‐WI provide about 33 and 60% capacity improvement respectively over a conventional FCA system using a single reuse factor to support two types of services. Copyright © 2004 John Wiley & Sons, Ltd.
Token bank fair queuing: a new scheduling algorithm for wireless multimedia services
Authors: Wong William K. , Tang Helen Y. , Leung Victor C. M.
Published: August 2004

The token bank fair queuing algorithm (TBFQ) is a novel scheduling algorithm that is suitable for wireless multimedia services. The bandwidth allocation mechanism integrates the leaky bucket structure with priority handling to address the problem of providing quality‐of‐service (QoS) guarantees to heterogeneous applications in the next generation packet‐switched wireless networks. Scheduling algorithms are often tightly integrated with the wireless medium access control (MAC) protocol. However, when heterogeneous wireless systems need to be integrated and interoperate with each other, it is desirable from the QoS provisioning standpoint to decouple scheduling algorithm from the MAC protocol. In this paper we propose a framework of seamless QoS provisioning and the application of TBFQ for uplink and downlink scheduling in wireless networks. We study its performance under a generic medium access framework that enables the algorithm to be generalized to provide QoS guarantees under various medium access schemes. We give a brief analysis of the algorithm and compare its performance with common scheduling algorithms through simulation. Our results demonstrate that TBFQ significantly increases wireless channel utilization while maintaining the same QoS, unlike many fair queuing algorithms, TBFQ does not require time‐stamping information of each packet arrival—an impractical feature in an already resource scarce environment. This makes TBFQ suitable for wireless multimedia communication. Copyright © 2004 John Wiley & Sons, Ltd.
Fair scheduling for spectrally efficient multi‐service wireless data provisioning
Authors: Sunay M. Oǧuz , Ekşim Ali
Published: August 2004

Efficient wireless packet data access is possible by exploiting multi‐user diversity. This is done by using an opportunistic multiple access system that allocates system resources to one user at a time while using adaptive modulation and coding. Based on this outcome, recently the IS‐856 system was developed. A scheduling algorithm provides resource allocation in the IS‐856 system, and its proper design is perhaps one of the most crucial aspects ensuring good system performance. We present a number of such algorithms in this paper, two of which are new, and provide a comparative performance evaluation. The proposed algorithms appear to have the best overall performance of achieving high system throughputs without diverging much from the optimal latency performance. We then show that the IS‐856 system can easily be adjusted to provide a multitude of services, each with different QoS requirements. Extensive performance evaluations show that good system performance can be maintained in the multi‐service scenario. The paper also presents means of providing multicast service provisioning in the IS‐856 system. Copyright © 2004 John Wiley & Sons, Ltd.
Out‐of‐band polling scheme for QoS support in wireless LANs
Authors: Lim Teck Meng , Tantra Juki Wirawan , Foh Chuan Heng , Lee Bu Sung
Published: August 2004

Recent researches in wireless local area networks (WLANs) have shown the challenges in providing an effective scheme to realize high throughput and transmission of real‐time traffic with a certain quality of service. This scheme must facilitate low worst‐case delay bounds and scale with the increase of data rate as technology advances. We introduce out‐of‐band polling scheme (OBPS), which separates the signalling for packet transmissions from the data channel; it uses an efficient polling method on a signalling channel for an access point to schedule packet transmissions with different priorities for upstream transmission. We also include a transmission sequences to efficiently schedule delivery of real‐time downstream packets. OBPS can adopt any packet scheduling algorithms to provide service differentiation. We choose deficit round robin scheduling algorithm for upstream and downstream traffic to provide rate differentiation and fairness. Through analytical and simulation results, we show that OBPS can achieve high throughput, provide rate differentiation and support bidirectional transmissions of real‐time packets. We derive upstream and downstream worst‐case delay bounds for OBPS, which serve as parameters for analysing scheduling algorithms that can be deployed to achieve a certain quality of service for real‐time packets. To illustrate that, we derive the worst‐case delay bounds of OBPS with DRR. Our delay bounds are realistic as it is based on upstream and downstream packet transmissions on a half‐duplex channel. We also show that OBPS is scalable for deployment in future high speed WLANs. Copyright © 2004 John Wiley & Sons, Ltd.
Energy‐aware delay‐constrained routing in wireless sensor networks
Authors: Akkaya Kemal , Younis Mohamed
Published: August 2004

Recent years has witnessed a growing interest in the applications of unattended wireless sensor networks. Due to the limitation of the energy supply that sensors have, almost all of the proposed routing protocols have aimed at energy efficiency as the ultimate objective and considered relaying data to a stationary gateway (sink). However, many new issues have been posed by the increasing interest in applications that demand certain quality of service (QoS) guarantees. Such issues even get more challenging when the gateway is mobile. In this paper, we propose an energy‐aware approach for routing delay‐constrained data. The approach pursues multi‐hop packet relaying to minimize transmission energy and employs weighted fair queuing (WFQ) packet scheduling methodology along with leaky bucket constrained data sources in order to provide soft real‐time guarantees for data delivery. Such employment of WFQ at each node provides a service differentiation between two different classes of traffic, namely real‐time and non‐real‐time traffic. In the case of a mobile gateway, uninterrupted data flow for both types of traffic is achieved by dynamic adjustment of the route set‐up to react to the gateway's departure out of transmission range of relaying nodes. Simulation results demonstrate the effectiveness of the proposed approach. Copyright © 2004 John Wiley & Sons, Ltd.
Worniu, a Snail family zinc‐finger protein, is required for brain development in Drosophila
Authors: Ashraf Shovon I. , Ganguly Atish , Roote John , Ip Y. Tony
Published: August 2004

The Snail family of zinc‐finger transcriptional repressors is essential for morphogenetic cell movements, mesoderm formation, and neurogenesis during embryonic development. These proteins also control cell cycle, cell death, and cancer progression. In Drosophila, three members of this protein family, Snail, Escargot, and Worniu, have essential but redundant functions in asymmetric cell division of neuroblasts. In addition, Snail is critical for early mesoderm formation and Escargot is required for maintaining diploidy in wing imaginal disc cells. In this report, we demonstrate that Worniu plays a role in brain development. We show that alleles of the l(2)35Da complementation group are mutants of worniu. The developing larvae of these mutant alleles fail to shorten their brainstems. The brain phenotype, as well as the lethality, of these mutants can be rescued by worniu transgenes. Moreover, RNAi experiments targeting the worniu transcript show the same nonshortening phenotype in larval brains. worniu is expressed in the neuroblasts of brain hemispheres and ventral ganglions. The results suggest that the loss of Worniu function within the neuroblasts ultimately causes the larval brainstem to fail to go through shortening during development. Developmental Dynamics 231:379–386, 2004. © 2004 Wiley‐Liss, Inc.
Foxj3, a novel mammalian forkhead gene expressed in neuroectoderm, neural crest, and myotome
Authors: Landgren Henrik , Carlsson Peter
Published: August 2004

Forkhead transcription factors are important regulators of animal development. Here, we describe the embryonic expression pattern for one of the novel forkhead genes that were discovered as a result of the mouse and human genome projects. It is most closely related to FoxJ2 and has been assigned the name FoxJ3. The 100‐kb, 13‐exon mouse Foxj3 gene on chromosome 4 encodes a 623 amino acid (aa) protein from an mRNA of at least 4.8 kb (Human FOXJ3: Chr 1, 627 aa, 5.3‐kb mRNA). During the stages of mouse development investigated (embryonic day [E] 8.5–E12.5) Foxj3 is expressed in neuroectoderm, in neural crest, and in many structures derived from neural crest cells, such as facioacoustic, trigeminal, and dorsal root ganglia. Stripes of expression appear at E10.5 in the location of myotomes and expand ventrally in a pattern similar to the developing body wall musculature. Developing limbs have a complex pattern of Foxj3 expression that at E12.5 colocalizes with the condensed mesenchyme of the skeletal primordia. Developmental Dynamics 231:396–401, 2004. © 2004 Wiley‐Liss, Inc.
Sox8is expressed at similar levels in gonads of both sexes during the sex determining period in turtles
Authors: Takada Shuji , DiNapoli Leo , Capel Blanche , Koopman Peter
Published: August 2004

A critical gene involved in mammalian sex determination and differentiation is theSry‐related geneSox9. In reptiles,Sox9resembles that of mammals in both structure and expression pattern in the developing gonad, but a causal role in male sex determination has not been established. A closely related gene,Sox8, is conserved in human, mouse, and trout and is expressed in developing testes and not developing ovaries in mouse. In this study, we tested the possibility ofSox8being important for sex determination or sex differentiation in the red‐eared slider turtleTrachemys scripta, in which sex is determined by egg incubation temperature between stages 15 and 20. We cloned partial turtleSox8andanti‐Müllerian hormone(Amh) cDNAs, and analyzed the expression patterns of these genes in developing gonads by reverse transcriptase‐polymerase chain reaction and whole‐mount in situ hybridization. WhileAmhis expressed more strongly in males than in females at stage 17,Sox8is expressed at similar levels in males and females throughout the sex‐determining period. These observations suggest that differential transcription ofSox8is not responsible for regulation ofAmh, nor responsible for sex determination in turtle. Developmental Dynamics 231:387–395, 2004. © 2004 Wiley‐Liss, Inc.
β‐catenin signaling marks the prospective site of primitive streak formation in the mouse embryo
Authors: Mohamed Othman A. , Clarke Hugh J. , Dufort Daniel
Published: August 2004

β‐Catenin signaling has been shown to be involved in triggering axis formation in several organisms, including Xenopus and zebrafish. Genetic analysis has demonstrated that the Wnt/β‐catenin signaling pathway is also involved in axis formation in the mouse, since a targeted deletion of β‐catenin results in embryos that have a block in anterior–posterior axis formation, fail to initiate gastrulation, and do not form mesoderm. However, because β‐catenin is ubiquitously expressed, the precise time and cell types in which this signaling pathway is active during early embryonic development remain unknown. Thus, to better understand the role of the Wnt/β‐catenin signaling pathway in axis formation and mesoderm specification, we have examined both the distribution and signaling activity of β‐catenin during early embryonic development in the mouse. We show that the N‐terminally nonphosphorylated form of β‐catenin as well as β‐catenin signaling is first detectable in the extraembryonic visceral endoderm in day 5.5 embryos. Before the initiation of gastrulation at day 6.0, β‐catenin signaling is asymmetrically distributed within the epiblast and is localized to a small group of cells adjacent to the embryonic–extraembryonic junction. At day 6.5 and onward, β‐catenin signaling was detected in the primitive streak and mature node. Thus, β‐catenin signaling precedes primitive streak formation and is present in epiblast cells that will go on to form the primitive streak. These results support a critical role for the Wnt/β‐catenin pathway in specifying cells to form the primitive streak and node in the mammalian embryo as well as identify a novel domain of Wnt/β‐catenin signaling activity during early embryogenesis. Developmental Dynamics 231:416–424, 2004. © 2004 Wiley‐Liss, Inc.
Integrins in the mouse myotome: Developmental changes and differences between the epaxial and hypaxial lineage
Authors: Bajanca Fernanda , Luz Marta , Duxson Marilyn J. , Thorsteinsdóttir Sólveig
Published: August 2004

Integrins are cellular adhesion receptors that mediate signaling and play key roles in the development of multicellular organisms. However, their role in the cellular events leading to myotome formation is completely unknown. Here, we describe the expression patterns of the α1, α4, α5, α6, and α7 integrin subunits in the mouse myotome and correlate them with the expression of several differentiation markers. Our results indicate that these integrin subunits may be differentially involved in the various phases of myogenic determination and differentiation. A detailed characterization of the myogenic cell types expressing the α4 and α6 subunits showed a regionalization of the myotome and dermomyotome based on cell‐adhesion properties. We conclude that α6β1 may be an early marker of epaxial myogenic progenitor cells. In contrast, α4β1 is up‐regulated in the intercalated myotome after myocyte differentiation. Furthermore, α4β1 is expressed in the hypaxial dermomyotome and is maintained by early hypaxial myogenic progenitor cells colonizing the myotome. Developmental Dynamics 231:402–415, 2004. © 2004 Wiley‐Liss, Inc.
Tooth patterning and enamel formation can be manipulated by misexpression of TNF receptor Edar
Authors: Pispa Johanna , Mustonen Tuija , Mikkola Marja L. , Kangas Aapo T. , Koppinen Petra , Lukinmaa Pirjo‐Liisa , Jernvall Jukka , Thesleff Irma
Published: August 2004

Signaling by Edar, a tumor necrosis factor receptor, is required for the development of ectodermal organs. Mutations in Edar or other molecules of the same signaling pathway cause ectodermal dysplasias in humans and mice. In these diseases, teeth are missing or malformed, and the development of hairs and several glands is hypoplastic. During tooth and hair development, Edar expression becomes patterned to ectodermal placodes and signaling centers. This localization has been suggested to be required for organogenesis. We have expressed Edar throughout the ectoderm using the keratin 14 promoter and show that this misexpression disrupts tooth patterning and differentiation. Tooth shape and cusp number are differentially affected, depending on the amount of transgene expression. In addition, tooth enamel formation is defective in a dose‐dependent manner. We speculate that the tooth patterning defects are caused by ectopic Edar activity outside the signaling centers. Developmental Dynamics 231:432–440, 2004. © 2004 Wiley‐Liss, Inc.
Homologs of vascular endothelial growth factor and receptor, VEGF and VEGFR, in the jellyfish Podocoryne carnea
Authors: Seipel Katka , Eberhardt Michael , Müller Peter , Pescia Elena , Yanze Nathalie , Schmid Volker
Published: August 2004

Vascular endothelial growth factors (VEGF) are the major inducers of vasculogenesis and angiogenesis in vertebrates. Their effects are mediated by receptor tyrosine kinases of the VEGF receptor (VEGFR) family located on endothelial cells and include stimulation of cell survival, proliferation, migration, and tube formation as well as regulation of vascular permeability. Here, we report the presence of VEGF and VEGFR homologous genes in a basal invertebrate of the phylum Cnidaria. The marine jellyfish Podocoryne carnea features a gastrovascular system consisting of the feeding organ, or manubrium, the radial and ring canals, and the tentacle bulbs. Expression analysis indicates that both genes are involved in tentacle and gastrovascular canal formation, indicating an early recruitment of the VEGF signalling pathway for morphogenetic processes leading to tube formation in metazoans. The evolutionary origin of the VEGF signalling pathway resides in the common ancestor of the Cnidaria and Bilateria. Developmental Dynamics 231:303–312, 2004. © 2004 Wiley‐Liss, Inc.
Design of discrete time polynomial nonlinear systems and its application to sequential control
Authors: Fujimoto Yasutaka
Published: August 2004

A systematic design methodology for discrete control systems is proposed, which is based on Galois field and Gröbner basis. The controller can be automatically designed using a model of the controlled plant. The controlled plant is represented on the Galois field. Then the inverse function of the plant is derived using the Gröbner basis so that the input variables are explicitly obtained as the function of the state variable and reference variable. An illustrative example of a material handling system is shown. The proposed method will realize cost reduction in software development and an improvement of reliability and safety of the PLC‐based systems. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(2): 60–72, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10221
Surface evaluation of LiNbO3 and LiTaO3 crystals etched using fluorine system gas plasma reactive ion etching
Authors: Fujii Takahiro , Yoshikado Shinzo
Published: August 2004

The etching characteristics of LiNbO3 and LiTaO3 single crystals have been investigated by performing plasma reactive ion etching (RIE) with CF4/Ar, CF4/H2, and CF2/Ar/H2 gas mixtures. The etched surface was evaluated by atomic force microscopy and X‐ray diffraction. The in situ surface temperature of the sample was measured during RIE. F atoms exist in the contamination layer on the surface etched using mixtures of CF4, Ar, and H2 gases. The etch rate was dependent on the crystal orientation. The etch rate of LiTaO3 was less than that of LiNbO3. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(2): 18–24, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10365
Measurement of tractive force and the new maximum tractive force control by the newly developed tractive force measurement equipment
Authors: Kawamura Atsuo , Takeuchi Keiichi , Furuya Takemasa , Cao Meifen , Takaoka Yosuke , Yoshimoto Kantaro
Published: August 2004

The acceleration and deceleration rate of a train depends on the tractive force. When the wheels of a train slip on the rails, the torque is decreased to avoid continuous slipping. This is done because the tractive coefficient between the wheels and the rails has a peak at a certain slip velocity. But this adhesive phenomenon has not been clearly examined or analyzed. For this purpose, we have developed new tractive test equipment. In this paper, we measure the tractive force with this equipment, and clarify the adhesive phenomenon. Then we propose new tractive force control and verify the effectiveness of this control scheme. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(2): 49–59, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10376
Numerical analysis of lamellar grating type three‐dimensional optical waveguides with periodic structure, using Fourier series expansion method
Authors: Momoda Michiko , Miyamoto Tokuo , Yasumoto Kiyotoshi
Published: August 2004

Three‐dimensional optical waveguides with periodic structure promise to play an important role in optical IC, and more accurate analysis of such waveguides is required. In this paper, an improved, more accurate Fourier series expansion method for an arbitrary number of grating periods making use of Floquet's theorem is applied to the numerical analysis of lamellar grating‐type periodic optical waveguides with rectangular cross section (glass substrate). In the numerical results, the characteristics of the reflected and transmitted powers of the guided and radiation fields versus wavelength are investigated when the depth of the grating grooves and the number of grating periods are varied. The effects of the groove depth and the number of periods on the powers of each mode are elucidated and the appropriate parameters for dominant guided mode propagation in the periodic waveguide are identified. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(2): 1–9, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20034
Politics, industry and the regulation of industrial greenhouse‐gas emissions in the UK and Germany
Authors: Bailey Ian , Rupp Susanne
Published: August 2004

This paper assesses the impact of ‘new’ environmental policy instruments (NEPIs), such as eco‐taxes, tradable permits and environmental agreements, on the politics of regulating industrial greenhouse‐gas emissions. Intense academic debate surrounds the extent to which environmental policy is driven by the public interest, public choices between actor and stakeholder interests, or embedded institutional traditions. However, the effects on environmental politics of the recent shift from direct regulation to NEPIs remain seriously under‐researched. Surveys and interviews with industry and policy‐makers on the implementation of United Kingdom and German climate policy indicate that, although economic pressures do influence the design of policy instruments, public choice is far from dominant; nor are industry reactions to particular NEPIs uniform between countries. This suggests that national institutional traditions are far more influential in informing policy choices and industry reactions to policy innovations than is often acknowledged. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
The EU emissions trading scheme allowance prices, trade flows and competitiveness effects
Authors: Klepper Gernot , Peterson Sonja
Published: August 2004

The upcoming European Emissions Trading Scheme (ETS) is one of the more controversial climate policy instruments. Predictions about its likely impact and its performance can at present only be made to a certain degree. As long as the National Allocations Plans are not finally settled the overall supply of allowances is not determined. In this paper, we will identify key features and key impacts of the EU ETS by scanning the range of likely allocation plans using the simulation model DART. The analysis of the simulation results highlights a number of interesting details in terms of allowance trade flows between member states, of allowance prices and of the role of the accession countries in the ETS. An important finding about the impact of the new ETS with respect to achieving emission reductions more efficiently, i.e. at lower cost, is that savings can only be realized if the cap on emissions is distributed between the ETS sector and the rest of the economy in such a way that the different abatement costs are taken into account. This would imply a relatively small allocation of emissions to the ETS sector. The second important result concerns the role of the accession countries. Even if they do not supply their hot air in the ETS market, they contribute substantially to the cost savings of the ETS by offering low‐cost abatement options. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Synthesis of a Novel Enantiopure Spiro‐B‐norestradiol Analogue by Multiple Pd‐Catalyzed Transformations
Authors: Tietze Lutz F. , Wiegand J. Matthias , Vock Carsten A.
Published: August 2004

The novel tetracyclic spiro compound 13 was synthesized by the use of two subsequent Pd‐catalyzed reactions. Firstly, the ortho‐bromobenzyl chloride 1 was coupled with the enantiopure boronic ester 8, obtained from the Hajos−Wiechert ketone in a chemoselective Suzuki‐type reaction to give 12 in 77% yield. Unexpectedly, the intramolecular Heck reaction then did not provide the annulated compound 6, but the spirocyclic compound 13, containing a quaternary carbon center, in 73% yield. The Heck reaction was also performed under microwave irradiation conditions, allowing a considerably shorter reaction time. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis and Biological Evaluation of Macrosphelide Cores
Authors: Ishihara Kentaro , Kawaguchi Takanori , Matsuya Yuji , Sakurai Hiroaki , Saiki Ikuo , Nemoto Hideo
Published: August 2004

The simplified 16‐membered core structures of macrosphelides were synthesized in high overall yields starting from methyl (+)‐ or (−)‐3‐hydroxybutyrate as the sole chiral source. The antiproliferative activities of these macrosphelide cores against murine colon 26‐L5 adenocarcinoma cells were examined, and the results suggest that the oxygen functional groups found in the natural products are essential for their bioactivities. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Economic stress and marital adjustment among couples: analyses at the dyadic level
Authors: Kinnunen Ulla , Feldt Taru
Published: August 2004

This survey study of 608 Finnish couples investigated the question of how economic stress is reflected in marital adjustment on the basis of the model presented by Conger and colleagues. We used the couple as a unit of analysis, performing a dyadic‐level analysis within the framework of LISREL models. The model showed that the path by which economic circumstances were linked to marital adjustment was as follows: poor economic circumstances were linked to economic strain, which was related to increased psychological distress, and psychological distress in turn was negatively reflected in marital adjustment. However, psychological distress only partially mediated the link between economic strain and marital adjustment: economic strain was also directly linked to decreased marital adjustment. In addition, there occurred crossover between partners' experiences. First, wives' psychological distress was negatively related to husbands' reports of marital adjustment and vice versa. Second, unemployment among men was directly linked to reports of marital adjustment among women: the longer the man's total spell of unemployment, the poorer the woman's marital adjustment. Copyright © 2004 John Wiley & Sons, Ltd.
The interplay of self‐interest and equity in coalition formation
Authors: van Beest Ilja , van Dijk Eric , Wilke Henk
Published: August 2004

In this paper we investigated the interplay of self‐interest and equity concerns in coalition formation by manipulating the number of units in which the coalition payoff is made available, and by manipulating the way people are allowed to interact. Results of three experiments showed that when the coalition payoff was such that members of each possible coalition could obtain an equitable payoff share, the outcome tended to be coalitions that also maximized the payoff of its members. However, when the payoff was such that people had to make trade‐offs between maximizing their payoff share and obtaining an equitable payoff share, it took longer to form a coalition and it was harder to maintain a coalition. Moreover, depending on the way people were allowed to interact, the final outcome was a coalition that maximized the payoff of its members or a coalition that provided them with an equitable payoff share. Copyright © 2004 John Wiley & Sons, Ltd.
Genetic association mapping under founder heterogeneity via weighted haplotype similarity analysis in candidate genes
Authors: Yu K. , Gu C. Charles , Province M. , Xiong C.J. , Rao D.C.
Published: August 2004

Taking advantage of increasingly available high‐density single nucleotide polymorphism (SNP) markers within genes and across genomes, more and more genetic association studies began to use multiple closely linked markers in candidate genes. A practical analytical challenge arising in such studies is the possibility that not all case chromosomes have inherited disease‐causing mutations from a common ancestral chromosome (founder heterogeneity). To alleviate the problem, we propose a method that applies a clustering algorithm to haplotype similarity analysis. The method identifies a sequence of nested subsets of case chromosomes by a peeling procedure, where each subset is relatively homogeneous. The average similarity score estimated from each subset in the sequence is compared to that estimated in controls, and a raw (unadjusted for multiple comparisons) P value is obtained. The test for the association between the trait and the candidate gene is based on the minimum raw P value observed in the comparison sequence, with its significance level estimated by a permutation procedure. The method can be applied to both haplotype and genotype data. Simulation studies suggest that our method has the correct type I error rate, and is generally more powerful than existing methods of haplotype similarity analysis. © 2004 Wiley‐Liss, Inc.
Brain activity underlying emotional valence and arousal: A response‐related fMRI study
Authors: Anders Silke , Lotze Martin , Erb Michael , Grodd Wolfgang , Birbaumer Niels
Published: August 2004

Emotional behavior is organized along two psychophysiologic dimensions: (1) valence, varying from negative to positive, and (2) arousal, varying from low to high. Behavioral responses along these dimensions are assumed to be mediated by different brain circuits. We recorded startle reflex modulation and skin conductance responses in healthy volunteers during functional magnetic resonance imaging (fMRI) while they viewed a set of emotional pictures and took verbal ratings of the emotional valence and arousal of each picture after scanning. Response‐related multiple correlation analysis revealed differential brain activity in five brain regions. Startle reflex changes, associated with the valence of a stimulus, correlated with activity in the amygdala, while verbal reports of negative emotional valence varied with insular activity. Peripheral physiologic and verbal responses along the arousal dimension varied with thalamic and frontomedial activity. Peripheral physiologic responses along both dimensions correlated with activity in somatosensory association areas in the anterior parietal cortex. In the valence dimension, activity in the left anterior parietal cortex was associated with highly correlating peripheral physiologic and verbal responses, suggesting that verbal reports of emotional valence might depend partly on brain circuits representing peripheral physiologic changes. Our data provide direct evidence for a functional segregation of brain structures underlying peripheral physiologic responses and verbal ratings along the emotional dimensions of valence and arousal. Hum. Brain Mapp. 23:200–209, 2004. © 2004 Wiley‐Liss, Inc.
Cortical activity to vibrotactile stimulation: An fMRI study in blind and sighted individuals
Authors: Burton Harold , Sinclair Robert J. , McLaren Donald G.
Published: August 2004

Blind individuals show visual cortex activity during Braille reading. We examined whether such cross‐modal activations reflect processing somatosensory stimuli independent of language by identifying cortical activity during a one‐back vibrotactile matching task. Three groups (sighted, early‐onset, and late‐onset [>12 years] blind) detected whether paired vibrations (25 and 100 Hz), delivered to the right index finger, differed in frequency. Three successive paired vibrations, followed by a no‐stimulation interval, were presented in a long event‐related design. A fixed effects average z‐score analysis showed increased activity throughout the visuotopic visual cortex, where it was mostly restricted to foveal and parafoveal eccentricities. Early blind showed the most extensive distribution of activity. Late blind exhibited activity mostly in similar regions but with declining response magnitudes with age of blindness onset. Three sighted individuals had suprathreshold activity in V1 but negative responses elsewhere in visual cortex. Mixed effects ANOVA confirmed group distinctions in defined regions (V1, V3, V4v, V7, LOC, and MT). These results suggest cross‐modal adaptation to tactile stimulation in visual cortex independent of language processes. All groups showed increased activity in left primary (S1) and bilateral second somatosensory areas, but without response magnitude differences between groups throughout sensorimotor cortex. Early blind showed the greatest spatial extent of S1 activity. Blind participants had more extensive bilateral activity in anterior intraparietal sulcus and supramarginal gyrus. Extensive usage of touch in Braille reading may underlie observed S1 expansions in the reading finger representation. In addition, learned attentiveness to touch may explain similar expansion of parietal tactile attention regions. Hum. Brain Mapp. 23:210–228, 2004. © 2004 Wiley‐Liss, Inc.
Morbidity of the neck after head and neck cancer therapy
Authors: van Wilgen C. Paul , Dijkstra Pieter U. , van der Laan Berend F. A. M. , Plukker John T. , Roodenburg Jan L. N.
Published: August 2004

Background.

Studies on morbidity of the neck after head and neck cancer therapy are scarcely described.

Methods.

Patients who underwent surgery, including neck dissection, with and without radiation therapy at least 1 year before the study were asked to participate. We assessed neck pain, loss of sensation, range of motion of the cervical spine, and shoulder pain.

Results.

Of the 220 patients who were invited, 153 (70%) participated in the study. Neck pain was present in 33% of the patients (n = 51), and shoulder pain was present in 37% of the patients (n = 57). Neuropathic pain of the neck was present in 32% (n = 49); myofascial pain, in 46% (n = 70); and joint pain, in 24% (n = 37). Loss of sensation of the neck was present in 65% (n = 99) and was related to type of neck dissection and radiation therapy. Range of motion of the neck was significantly decreased because of the neck dissection and/or radiation therapy in lateral flexion away from the operated side.

Conclusions.

The occurrences of morbidity of the neck after cancer therapy were considerable and consisted of neck pain, loss of sensation, and decreased range of motion. © 2004 Wiley Periodicals, Inc. Head Neck 26: 785–791, 2004
Radiation‐induced Xerostomia in patients with head and neck cancer: Pathogenesis, impact on quality of life, and management
Authors: Chambers Mark S. , Garden Adam S. , Kies Merrill S. , Martin Jack W.
Published: August 2004

Background.

Xerostomia is a common, debilitating complication of radiation therapy (RT) for head and neck cancer. This article reviews the pathogenesis of radiation‐induced xerostomia, its impact on quality of life (QOL), and treatment options.

Methods.

Virtually all patients undergoing RT for head and neck cancers have xerostomia, which causes oral discomfort and pain, increased dental caries and oral infection, and difficulty speaking and swallowing. This significantly impairs QOL and can compromise nutritional intake and continuity of cancer therapy. The literature describing pathogenesis, impact on QOL of radiation‐induced xerostomia, and preventive and interventional therapies was reviewed.

Results.

Current management strategies include stringent dental and oral hygiene; parotid‐sparing radiation techniques to prevent or minimize xerostomia; and pharmacotherapies, such as salivary substitutes and sialogogues. Future strategies may include advanced three‐dimensional intensity‐modulated RT techniques, salivary gland transfer, newer sialogogues, and gene therapy.

Conclusions.

New treatment approaches to xerostomia from RT for head and neck cancer may result in significant improvement in patient QOL. © 2004 Wiley Periodicals, Inc. Head Neck 26: 796–807, 2004
Secondary end‐to‐end repair of extensive facial nerve defects: Surgical technique and postoperative functional results
Authors: Piza‐Katzer Hildegunde , Balogh Brigitta , Muzika‐Herczeg Emilia , Gardetto Alexander
Published: August 2004

Background.

Repair of the transected facial nerve is imperative for restoration of muscle function, including the ability to produce appropriate facial expressions. Injury might involve the main trunk and its several branches. Restoration of function presupposes meticulous repair of all injured nerve branches.

Methods.

Here we report three cases of secondary tension‐free end‐to‐end coaptation of a transected trunk and branches of the facial nerve by removal of the superficial part of the parotid gland.

Results.

Facial tone and symmetry at rest and motion were achieved. In two patients, a slight residual synkinesis is observed under stress.

Conclusions.

Direct end‐to‐end coaptation of the facial nerve and its branches by the technique described should be considered before deciding on grafts or rerouting procedures to deal with gaps of up to 15 mm. This technique is not recommended in the presence of infection and nerve defects. Intensive postoperative physiotherapy is required for optimal results. © 2004 Wiley Periodicals, Inc. Head Neck 26: 770–777, 2004
Statistical determinants of dendritic morphology in hippocampal pyramidal neurons: A hidden Markov model
Authors: Samsonovich Alexei V. , Ascoli Giorgio A.
Published: August 2004

Dendritic structure is traditionally characterized by distributions and interrelations of morphometric parameters, such as Sholl‐like plots of the number of branches versus dendritic path distance. However, how much of a given morphology is effectively captured by any statistical description is generally unknown. In this work, we assemble a small number of standard geometrical parameters measured from experimental data in a simple stochastic algorithm to describe the dendrograms of hippocampal pyramidal cells. The model, consistent with the hidden Markov framework, is feedforward, local, and causal. It relies on two “hidden” local variables: the expected number of terminal tips in a given subtree, and the current path distance from the soma. The algorithm generates dendrograms that statistically reproduce all morphological essentials of dendrites observed in real neurons, including the distributions of branching and termination points, branch lengths, membrane area, topological asymmetry, and (assuming passive membrane parameters within physiological range) electrotonic characteristics. Thus, this algorithm and the small number of its morphometric parameters constitute a remarkably complete description of the dendrograms of hippocampal pyramidal cells. Specifically, it is found that CA3 and CA1 basal dendrites and CA3 apical dendrites can each be described as homogeneous morphological classes. In contrast, the accurate generation of CA1 apical dendrites necessitates the separate sampling of two types of branches, main and oblique, suggesting their derivations from different developmental mechanisms (terminal and interstitial growth, respectively). We further offer a plausible biophysical interpretation of the model hidden variables, relating them to microtubules and other intracellular resources. © 2004 Wiley‐Liss, Inc.
Folic acid: neurochemistry, metabolism and relationship to depression
Authors: Paul Raymond T. P. , McDonnell Anne P. , Kelly Christopher B.
Published: August 2004

The associations of folic acid and its derivatives with depressive disorder are reviewed. Derivatives of folic acid such as biopterins and the synthesis of S‐adenosyl methionine (SAM) are known either to be associated with improvement or to have a direct therapeutic effect in depressive disorder. Studies investigating plasma and red cell folic acid levels in depressed patients have used differing assay methodologies which make comparison difficult, although there is substantial evidence of the association between depressive disorder (particularly severe depression) and low folic acid levels. The few studies available suggest folic acid has either antidepressant properties or can act as an augmenting agent for standard antidepressant treatment. A recently discovered genetic variant (5,10 MTHFR) leading to altered folic acid metabolism may explain why some individuals are vulnerable to the effects of folic acid deficiency, despite adequate intake. The links of 5,10 MTHFR to the presence of depressive disorder in the community are being investigated. Copyright © 2004 John Wiley & Sons, Ltd.
Efficacy and tolerability of mirtazapine and sertraline in Korean veterans with posttraumatic stress disorder: A randomized open label trial
Authors: Chung Moon Yong , Min Kyung Ho , Jun Yong Ju , Kim Sung Soo , Kim Wan Chul , Jun Eun Mi
Published: August 2004

Background

The aim of this study was to investigate the potential use of mirtazapine in Korean veterans diagnosed with PTSD, by comparing it with sertraline, a drug approved for use in PTSD in the USA.

Methods

Efficacy was evaluated by the clinician administered PTSD scale (CAPS‐2), the Hamilton rating scale for depression (HAMD‐17) and the clinical global impression scale (CGI), at baseline and at weeks 1, 2 and 6. A response was defined as a ≥ 30 % decrease in CAPS‐2 total severity, a ≥ 50 % decrease in total HAMD‐17 score, and a CGI‐I score < 3.

Results

51 patients on mirtazapine (mean age/duration of illness: 59.1/33.5 years) and 49 on sertraline (mean age/duration of illness: 60.6/35.6 years) completed the study. The mean daily dosage was 34.1 mg for mirtazapine and 101.5 mg for sertraline. On the CAPS‐2 total score more patients responded in the mirtazapine group at week 1 (13 vs 2 %) and week 2 (51 vs 31 %). At week 6 this difference was statistically significant (88 % vs 69 %, p = 0.039) on the CAPS‐2 total score. The HAMD‐17 total score and CGI‐I score decreased in both groups, with no significant differences between th groups on all time points. The main side effects for the mirtazapine group were: dry mouth (19.6 %), constipation (19.6 %), somnolence (15.7 %) and weight gain (1.96 %); and for the sertraline group: indigestion (14.3 %), palpitation (6.1 %), agitation (2.0 %), epigastric soreness (2.0 %), insomnia (2.0 %) and sexual dysfunction (2.0 %).

Conclusion

Mirtazapine appeared to be an effective and well‐tolerated treatment for PTSD in Korean veterans. Copyright © 2004 John Wiley & Sons, Ltd.