bluuebunny/crossref_metadata_2025 huggingface dataset:
Resource assignment method on Internet service with a unidirectional link
Authors: Takei Jun , Izumiyama Hidetaka
Published: September 2004

With the rapidly spreading use of the Internet, many systems for connection to the Internet using various media and methods have appeared. One is a system using a satellite link as a unidirectional link, which is expected to provide broadband Internet service to areas in which a ground Internet environment has not yet been developed. However, most of the protocols which are regarded as standard on the Internet assume that the links composing the Internet can provide bidirectional communications. Consequently, when a unidirectional link is used as a part of the network, it is difficult to make direct use of the protocols which are considered standard on the Internet. Consequently, this paper considers the situation in which Internet connection service is provided by using a unidirectional link, and proposes and implements the required dynamic assignment of network resources and the associated management scheme. The system is also evaluated in the actual environment. It is shown that by applying the proposed method, it becomes possible to utilize a unidirectional link combined with a bidirectional link on the ground, resulting in an efficient Internet connection environment. It is also shown that the connection to the network is provided without constraints on its use. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(1): 82–90, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10104
Node placement algorithms for shuffle‐like packet‐switched networks with wavelength‐division multiplexing
Authors: Yokohira Tokumi , Okamoto Takuji
Published: September 2004

The shuffle‐like network (SL‐Net) is known as a logical topology for WDM‐based multihop packet‐switched networks. We propose two heuristic node placement algorithms for the SL‐Net to decrease the average end‐to‐end packet transmission delay for a given traffic matrix. The principal idea is to prevent too many traffic flows from overlapping on any link. To attain this objective, one algorithm selects nodes one by one in decreasing order of the sums of their sending and receiving traffic requirements, and places them so that the maximum traffic in the links is minimal. The other selects nodes in the same way, and places then so that the average distance among the nodes which have already been placed is as large as possible. Numerical results for four typical traffic matrices show that either of the proposed algorithms has better performance than the conventional algorithms for each matrix. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(1): 72–81, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10184
Avoiding TCP false retransmission in LEO satellite network using TTL information
Authors: Tsunoda Hiroshi , Ohta Kohei , Kato Nei , Nemoto Yoshiaki
Published: September 2004

Recently, more research attention has been focused on LEO (Low Earth Orbit) satellite networks connected to ISL (Inter Satellite Link). If terrestrial and LEO satellite networks are seamlessly interconnected by TCP/IP protocols, a global network that covers the whole earth can be integrated into the Internet. However, handover and rerouting issues in LEO satellite networks cause delay variance, and the delay variance can degrade performance of TCP, originally designed for wired networks, because of unnecessary retransmission. In this paper, we propose a method for avoiding the unnecessary retransmission by using the TTL (Time To Live) field in IP headers. Our simulation results show how our mechanism is effectively avoiding unnecessary retransmissions. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(1): 64–71, 2005; Published online in Wiley InterScience (www.interscience.wiley. com). DOI 10.1002/ecja.10205
A cavity‐backed spiral antenna with an unbalanced feed system—analyses using FD‐TD and moment methods
Authors: Hirose Kazuhide , Saito Naoto , Nakano Hisamatsu
Published: September 2004

The FD‐TD method and the moment method are used to analyze a two‐wire square spiral antenna backed by a conducting square cavity (SAC). The SAC is fed from a coaxial line without a balun circuit. First, the SAC is analyzed using the FD‐TD method. The SAC design is based on radiation characteristics of a two‐wire square spiral antenna backed by a conducting plane reflector (SAR). It is found that the frequency bandwidth for a 3‐dB axial‐ratio criterion is 12% (18% for SAR), with a gain of 7 dBi (8 dBi for SAR). Second, the moment method is used to analyze a wire‐grid model of the SAC. Grid sizes appropriate for the analysis are determined on the basis of the FD‐TD solutions. It is revealed that the grid size for the cavity side plates is 1.3 times larger than that for the cavity bottom plate. Third, a two‐SAC array is analyzed to reveal the mutual coupling. Calculation shows that the decoupling factor is larger than that for a two‐SAR array by approximately 3 dB. The computation time and memory size required for the analyses are compared between the two cases for the FD‐TD and the moment methods. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(1): 53–63, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10211
Multilevel zone‐based hierarchical link state routing with location search technique applying hierarchical request for mobile ad hoc networks
Authors: Takahashi Michito , Bandai Masaki , Sasase Iwao
Published: September 2004

To reduce communications overhead and location search overhead and to realize a hierarchical network, we propose multilevel zone‐based hierarchical link state (ZHLS) routing with a location search technique applying hierarchical request for mobile ad hoc networks. The proposed protocol reduces the communication overhead by hierarchizing the network into multilevel zones. In this protocol, a high‐level zone consists of several low‐level zones. To reduce location search overhead, location search is performed by each higher‐level gateway node searching its own lower‐level zones. The proposed protocol enables the source node to request the zone ID of the destination node for each zone. By mathematical analysis and simulations, we show that the proposed protocol reduces communications overhead and location search overhead. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(1): 44–52, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10228
Effect of propagation delay and RTS packet recognition time on MACA
Authors: Matsuno Hiroshi , Ishinaka Hideyuki , Shigeyasu Tetsuya
Published: September 2004

The authors analytically derive the throughput performance of the media access control (MAC) protocol MACA, which has become the prototype of options used in IEEE802.11 for reducing the effects of hidden terminals. This derivation indicates that the MACA throughput performance basically is affected by the propagation delay and RTS recognition time. Also, by comparing MACA with CSMA, which is a typical contention mode MAC protocol, the authors show that (1) if the RTS recognition time is sufficiently small, MACA has better performance than CSMA even in a network in which no hidden terminal exists, and (2) when relatively large data packets are transmitted and received, MACA functions effectively. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(1): 21–31, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20147
Packet size based dynamic scheduling for assured services in Diffserv network
Authors: Minagawa Tadasuke , Kitami Tokuhiro
Published: September 2004

Diffserv (Differentiated Service) [1] is a promising technique to realize scalable QoS control in the Internet. Therefore, extensive efforts have been made regarding the practical use of this technique. Diffserv has already been introduced in some networks. Control functions for Diffserv are installed in the edge router and core router. This enables a scalable QoS control as mentioned above. Herein we propose a new active queue management scheme for AF services guaranteeing minimum bandwidth provided that RIO and WFQ are used as the basic QoS control mechanisms. The proposed method dynamically controls queue threshold values of RIO and bandwidth allocation of WFQ taking into account the packet sojourn time and packet size of each head of line packet. Simulation results show that the proposed scheme reduces the packet delay time for higher‐priority QoS classes when packets with longer size are frequently transmitted. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(1): 12–20, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20151
Improvement of frequency extraction accuracy of linear predictive analysis by a combination of autocorrelation and integral procedure for noise wave shape
Authors: Murakawa Kazuo , Ishiyama Fumihiko , Yamane Hiroshi , Hattori Mitsuo
Published: September 2004

The accurate and rapid identification or detection of the electrical noise sources causing noise malfunctions in communication equipment is an important issue in determining corrective measures. In this paper, we explain an improvement in the frequency extraction accuracy of linear predictive analysis for noise waveforms in order to identify the noise sources from noise waveforms such as the audible noise generated by communication equipment like telephones and noise currents penetrating into the communication equipment. In this study, we propose an improvement of the frequency extraction accuracy of linear predictive analysis by using correlation and integration. This method preserves specific frequency components of the original noise waveforms although correlation and integration are performed. In this paper, we divide the noise waveform into finite‐length segments, correlate and integrate the time series data within a given segment, and formulate dynamic frequency analysis (time–frequency analysis) based on linear predictive analysis for the time series data in the postprocessing. We also verify the effectiveness of the proposed method by using known noise waveforms. The result of applying the proposed method to a noise waveform that convolved white noise with sine wave signals having known frequencies was clearly the ability to extract the frequencies of the sine waves included in the noise waveform even for a signal‐to‐noise ratio (SNR) of 0 dB with an error range of about 10 to 15%. This assumes that the frequencies of the sine waves included in the noise can be extracted even under the worst case SNR due to the suppression of white noise by the correlation and the emphasis of the low‐frequency components by the integration. Thus, we show that the characteristic frequencies in the noise waveform can be accurately extracted by using linear predictive analysis combining correlation and integration, and present the remaining issues. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(1): 1–11, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20153
Direction of arrival estimation by means of genetic algorithm
Authors: Maruyama Takashi , Tsuji Yosuke , Kuwahara Yoshihiko
Published: September 2004

The estimation of arrival direction using the Hopfield neural network (HNN) has the feature that the wave number estimation, which is needed in the eigenvalue decomposition, is not required, and the signal with a high correlation can be estimated without applying the moving average. On the other hand, HNN is the local minimum search procedure, and it can be the case that the result of estimation may not be highly reliable. This study notes that the energy function of HNN is a scalar value that can be determined only by the output vector of the neuron. An arrival direction estimation algorithm is proposed, in which the output state of the neuron is determined by the genetic algorithm (GA) so that the energy is minimized, using the energy function as the evaluation function and the neuron output state as the chromosome. The effectiveness of the method is examined through Monte Carlo simulation and experiment. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(1): 58–67, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20072
A study of spread code in the 2.4‐GHz‐band DS‐SS wireless LAN system
Authors: Mori Hiroki , Sasaoka Hideichi
Published: September 2004

The CCK scheme is often used in the 2.4‐GHz‐band DS‐SS wireless LAN system, but the degradation of the transmission quality due to the noise emphasis is a problem, since a hard‐decision decoding is applied to the decoding of information. As another aspect, few studies in the wireless LAN system have evaluated the co‐channel interference characteristics considering the cell allocation. Consequently, this study intends to improve the quality of the wireless LAN system. The maximum‐likelihood decoding is applied to MBOL system of spread code length 4, 8, and 16, and the proposed system using a spread code (code length 12). BER performance is evaluated. In addition, the spectrum efficiency is evaluated as dependent on the cell allocation, considering the interference characteristics. It is verified as a result of simulation that the system using the proposed spread code (code length 12, 16 kinds and minimum distance 6) is effective in terms of the BER performance and the spectrum efficiency. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(1): 48–57, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20077
Performance estimation of surface acoustic wave motor using simulation model of friction drive
Authors: Asai Katsuhiko , Kurosawa Minoru Kuribayashi
Published: September 2004

The contact states of the slider and stator substrate greatly affect the drive performance of a surface acoustic wave motor. The contact states are determined by factors such as the friction coefficient, vibration amplitude, rigidity of the contact surface, contact time with the Rayleigh wave, and slider speed. A model was proposed that represented the relationship between these factors and the drive performance. However, guidance has not been provided on how these values should be changed to improve the drive performance. In this research, we use a friction drive model we proposed to analyze the effect of the changes in these parameters on the drive performance and to discuss the motor design and the drive conditions based on evaluations from the perspectives of the drive power, output, and efficiency. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(1): 37–47, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ ecjc.20079
An m‐derived ladder high‐pass SAW filter
Authors: Misu Kochiro , Ibata Koji , Wadaka Shusou , Nagatsuka Tsutomu , Murai Koji , Yoshida Kenji
Published: September 2004

Since excellent characteristics can be realized in the gigahertz range with a small size, SAW filters have been used widely as RF (radio frequency) filters for mobile communications terminals. In particular, since the insertion loss of the RF filter impacts the receiving sensitivity and transmitting power efficiency of the terminals, the demand for lower loss is substantial. In this paper, a one‐port SAW resonator is used as the series element and a series circuit consisting of a capacitor and an inductor is used as the shunt element in an m‐derived ladder filter. Its configuration, design procedure, and design and test results are presented. In spite of a simple circuit configuration, this filter can realize a low loss characteristic. The fabricated filter for 900 MHz exhibited excellent properties with an insertion loss of less than 1 dB and an out‐of‐band attenuation of more than 33 dB. The effectiveness of this filter is therefore demonstrated. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(1): 27–36, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20091
Investigation of the model for path selection behavior in open space
Authors: Umemura Hiroyuki , Watanabe Hiroshi , Matsuoka Katsunori
Published: September 2004

In this study, we investigate the model for the human strategy of path selection behavior in an open space. In the experiment, a moving obstacle was displayed in an immersive virtual reality system. Subjects were required to walk from a start point to a goal point in the virtual space and their walking trajectories were measured. The model for the path selection strategy, composed of two stages of global path planning and local direction control, was proposed to account for the experimental results. In the global path planning stage, the model determined a transit position that minimizes an equation consisting of terms about walking distance and dangerousness. In the local direction control stage, a walking direction was calculated at every step to avoid a moving obstacle. The results of simulation well accounted for the experimental results in general. Moreover, we applied the model to the results of another experiment in order to investigate the generality of the model. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(1): 18–26, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20111
Higher‐order correlation analysis of pitch fluctuations in sustained normal vowels by the method of surrogate data
Authors: Tokuda Isao , Miyano Takaya , Aihara Kazuyuki
Published: September 2004

The pitch fluctuations observed in the sustained pronunciation of voiced sounds are known to be indispensable for perception of voiced sound as natural human pronunciation. In speech synthesis, it is necessary to carefully identify the statistical properties of the pitch fluctuations that are required in order for the reproduced speech to maintain the quality of the original speech. From research to date, it is known that maintaining the second‐order correlation structure is important for the realization of natural pitch fluctuations. No information is available on the importance of higher‐order correlations above third order. In the present research, a higher‐order correlation analysis of pitch fluctuations is carried out by the surrogate method. The effect of the correlation structures of third and higher orders on the naturalness of vowels is studied. The results show that reproduction of the correlation configuration of third and higher orders is important in addition to the second‐order correlation in the synthesis of pitch fluctuations. Possible approaches based on nonlinear models are discussed. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(1): 9–17, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20113
Three‐dimensional image input system using parallel projection images
Authors: Takahashi Hideya , Kimura Mitsuo , Shimizu Eiji
Published: September 2004

Recently, three‐dimensional image display techniques have been implemented in a number of areas. In particular, in the medical field, three‐dimensional displays are needed for operation support displays and medical diagnosis. Three‐dimensional image display techniques can be subdivided into methods using binocular parallax and methods using holography. The former cause eye fatigue, while the latter involve an enormous amount of information and no suitable display device exists for them. In order to overcome these problems, the authors have proposed a method of reconstruction of parallax rays. In this method, rays are reconstructed in various directions from the display and a three‐dimensional image is created by the point light sources reconstructed at the intersections of the rays. This is a type of integral imaging method. Hence, in order to display three‐dimensional images, it is necessary to acquire the information about the rays to be reconstructed and to photograph the parallax images of the object. To this end, many cameras must be lined up, so that picture taking in a small space is difficult. Hence, in this paper we propose a three‐dimensional image input system using parallel projection images that can acquire ray information by simply moving a pinhole instead of using several moving cameras. An experimental system was built and the effectiveness of the present method was demonstrated. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(1): 1–8, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20116
Smooth transition exponential smoothing
Authors: Taylor James W.
Published: September 2004

Adaptive exponential smoothing methods allow a smoothing parameter to change over time, in order to adapt to changes in the characteristics of the time series. However, these methods have tended to produce unstable forecasts and have performed poorly in empirical studies. This paper presents a new adaptive method, which enables a smoothing parameter to be modelled as a logistic function of a user‐specified variable. The approach is analogous to that used to model the time‐varying parameter in smooth transition models. Using simulated data, we show that the new approach has the potential to outperform existing adaptive methods and constant parameter methods when the estimation and evaluation samples both contain a level shift or both contain an outlier. An empirical study, using the monthly time series from the M3‐Competition, gave encouraging results for the new approach. Copyright © 2004 John Wiley & Sons, Ltd.
Combination forecasts of output growth in a seven‐country data set
Authors: Stock James H. , Watson Mark W.
Published: September 2004

This paper uses forecast combination methods to forecast output growth in a seven‐country quarterly economic data set covering 1959–1999, with up to 73 predictors per country. Although the forecasts based on individual predictors are unstable over time and across countries, and on average perform worse than an autoregressive benchmark, the combination forecasts often improve upon autoregressive forecasts. Despite the unstable performance of the constituent forecasts, the most successful combination forecasts, like the mean, are the least sensitive to the recent performance of the individual forecasts. While consistent with other evidence on the success of simple combination forecasts, this finding is difficult to explain using the theory of combination forecasting in a stationary environment. Copyright © 2004 John Wiley & Sons, Ltd.
Cryptic insertion producing two NUP98/NSD1 chimeric transcripts in adult refractory anemia with an excess of blasts
Authors: La Starza Roberta , Gorello Paolo , Rosati Roberto , Riezzo Antonio , Veronese Angelo , Ferrazzi Eros , Martelli Massimo F. , Negrini Massimo , Mecucci Cristina
Published: September 2004

We performed cytogenetic and molecular studies on an adult patient with refractory anemia with an excess of blasts with an add(11)(p15). Multicolor fluorescence in situ hybridization (FISH) identified the extra material on 11p as belonging to chromosome 15. Metaphase FISH with probes for chromosomes 5, 11, and 15 revealed a complex four‐break rearrangement. Clone RP5‐1173K1, containing exons 10–20 of the NUP98 gene, gave three fluorescence signals on the normal 11, the der(5), and the der(15). 3′‐RACE‐PCR identified an in‐frame fusion between NUP98 and NSD1, which was confirmed by RT‐PCR. Two different spliced forms, that is, NUP98 exon 11/NSD1 exon 6 and NUP98 exon 12/NSD1 exon 6, were detected. The reciprocal NSD1/NUP98 was not found. A dual‐color experiment with RP5‐1173K1 and CTC‐549A4, spanning the entire NSD1 gene, indicated an insertion of NUP98 into the NSD1 locus. This is the first report of an adult with myelodysplastic syndrome (MDS) harboring an NUP98/NSD1 fusion resulting from insertion of 5′‐NUP98 into the NSD1/5q35 locus. © 2004 Wiley‐Liss, Inc.
Evidence for a single clay/temper source for the manufacture of Middle and Late Helladic Aeginetan pottery from Asine, Greece
Authors: Dorais Michael J. , Lindblom Michael , Shriner Christine M.
Published: September 2004

In an effort to further characterize the Middle and Late Helladic pottery industry on Aegina, we have analyzed amphibole in 23 sherds imported to the coastal settlement of Asine. The sherds derive from vessels of different classes and shapes and range in age from MH I‐II to LH IIIB‐IIIC Early. All sherds come from vessels that carry manufacturing marks, and their amphiboles have compositions that are incompatible with those of Methana, Poros, and Melos. Twenty of the sherds have amphiboles that are identical in composition and overlap a narrow range of amphibole compositions found in specific lava flows on the northern portion of Aegina. Given that the dacites across Aegina contain amphiboles with a wide range in compositions, we suggest that the narrow range of amphibole compositions in the sherds indicates that they were derived from either a specific clay source on the island, located in a stream system southeast of the prehistoric settlement at Kolonna, or that the potters used a specific temper source along the same stream system. Multiple clay or temper sources would have produced sherds with a broader range of amphibole compositions reflecting the diversity of amphibole compositions found on Aegina. One sherd has amphibole compositions indicative of an additional Aeginetan component that is not found in the other sherds. Two sherds have amphiboles with compositions that do not match any known reference amphiboles for Aegina, Methana, Poros, or Melos. These may have been derived from still unsampled dacites on Aegina or have been manufactured from materials located outside the Saronic Gulf. © 2004 Wiley Periodicals, Inc.
Geoarchaeological context of late Pleistocene and early Holocene occupation at the Cooper's Ferry site, western Idaho, USA
Authors: Davis Loren G. , Schweger Charles E.
Published: September 2004

Archaeological excavations at the Cooper's Ferry site (10IH73), located in the lower Salmon River canyon of western Idaho, revealed a stratified sequence of cultural occupations that included a pit feature containing stemmed points. However, radiocarbon ages determined on charcoal and bone in the pit feature range between ca. 12,000 yr B.P. and 7300 yr B.P. By considering the effects of postdepositional processes on dated samples, and by comparing the lithostratigraphy, pedostratigraphy, and stable isotope geochemistry of pedogenic carbonates from Cooper's Ferry with other well‐dated stratigraphic sections in the canyon, site geochronology is clarified. Based on the presence of key radiocarbon ages and distinctive stratigraphic criteria, we argue that the initial occupation and interment of lithic artifacts in a pit feature at Cooper's Ferry occurred during the late Pleistocene, between ca. 11,410 and 11,370 yr B.P., and not during the early Holocene. Records of geomorphic change and paleoenvironmental proxy data from the site reveal that early occupation in the lower Salmon River canyon corresponds with evolving riparian ecosystems, which must be considered as a contextual aspect of local prehistoric cultural ecology. © 2004 Wiley Periodicals, Inc.
Effect of prior cognitive state on resting state networks measured with functional connectivity
Authors: Waites Anthony B. , Stanislavsky Alexandra , Abbott David F. , Jackson Graeme D.
Published: September 2004

To address the extent to which functional connectivity measures an absolute brain state, we observed the effect of prior performance of a language task on resting‐state networks in regions associated with language. Six subjects were imaged during rest before and after a block‐design language task. Connectivity maps were generated for each of four language regions (identified from analysis of the language activation portion of the study) in each subject for both rest periods. Conjunction analysis demonstrated distinct networks of voxels for each seed region, indicating separate functional subnetworks associated with the different regions. In a comparison of rest before and after the activation task widespread and significant changes were observed in all individuals, suggesting that the measured resting state network reflects a dynamic image of the current brain state. At the group level, an extended network was observed that was largely persistent over time. Even at the group level an increase in connectivity was observed between left and right middle frontal gyri, and between posterior cingulate cortex and medial frontal cortex in the rest after the language task. These results suggest that functional connectivity may be a powerful measure of cognitive state, sensitive to differences between controls and patients together with the particular cognitive processing occurring during the rest state. Hum. Brain Mapping 24:59–68, 2005. © 2004 Wiley‐Liss, Inc.
Persistence of isolated antibodies to woodchuck hepatitis virus core antigen is indicative of occult infection
Authors: Coffin Carla S. , Pham Tram N.Q. , Mulrooney Patricia M. , Churchill Norma D. , Michalak Tomasz I.
Published: September 2004

Antibodies against virus nucleocapsid (anticore) normally accompany hepadnaviral hepatitis but they may also occur in the absence of symptoms and other serological indicators of the infection. This situation can be encountered following a clinically and serologically unapparent exposure to hepatitis B virus (HBV) or after recovery from hepatitis B. In this study, woodchucks inoculated with woodchuck hepatitis virus (WHV) were investigated to determine the relationship between anticore detection and the molecular status of virus replication in a primary WHV surface antigen (WHsAg)-negative infection or long-after resolution of WHV hepatitis. Serial, parallel samples of sera, peripheral blood mononuclear cells (PBMC) and liver tissue, collected for more than 5 years after inoculation with virus, were examined for WHV DNA by highly sensitive polymerase chain reaction (PCR)/nucleic acid hybridization assays. Sera were also tested for WHV DNA after DNase treatment and for WHV DNA and WHsAg after concentration in sucrose. Liver and PBMC were examined for WHV covalently closed circular DNA and viral RNA transcripts by PCR-based techniques to assess virus replication status. The study showed that anticore antibodies existing in the absence of other serological markers are a reliable indicator of occult WHV infection. This state can be accompanied by traces of circulating particles behaving as intact virions and by intermittent minimal-to-mild liver inflammation. In conclusion, the long-term presence of anticore antibodies alone is a consequence of sustained restimulation of the immune system by virus nucleocapsid produced during low-level hepadnaviral assembly. (Hepatology 2004.)
Depression, smoking abstinence and HPA function in women smokers
Authors: Pomerleau Ovide F. , Pomerleau Cynthia S. , Snedecor Sandy M. , Gaulrapp Stefanie , Brouwer Rebecca Namenek , Cameron Oliver G.
Published: September 2004

To determine whether smokers with a history of depression are differentially susceptible to smoking withdrawal, depressed mood induction and/or hypothalamic–pituitary–adrenal (HPA) axis dysregulation during smoking abstinence, 24 women smokers with and without such a history were studied. During one 5‐day interval, participants smoked ad libitum; during a second they abstained. On day 4, the participants were exposed to the Velten mood induction procedure (VMIP). Participants were then instructed to take 1 mg dexamethasone at 11 pm. At 4 pm on day 5, blood samples were withdrawn to determine the cortisol and ACTH response. Despite lower baseline cotinine levels, history‐positive participants displayed more pronounced overall withdrawal distress than did history‐negative participants, regardless of condition. The VMIP increased depression as well as negative responses on other profile of mood states subscales. Despite many overall group differences, no significant main effects for smoking condition nor interaction effects emerged. All participants evinced cortisol suppression in response to dexamethasone during both conditions, but the degree of suppression did not differ as a function of either abstinence or depression history. In history‐positive smokers, however, ACTH levels trended toward overall elevation and showed almost no suppression during abstinence; thus exacerbation of HPA dysregulation in history‐positive smokers during smoking abstinence cannot be ruled out. Copyright © 2004 John Wiley & Sons, Ltd.
Effects of a Korean traditional herbal remedy on psychoneuroendocrine responses to examination stress in medical students: a randomized placebo‐controlled trial
Authors: Lee Myeong Soo , Park Ki‐Won , Moon Sun‐Rock
Published: September 2004

The aim of this study was to investigate the efficacy of Ondamtanggamibang, a Korean traditional herbal remedy, as a treatment of stress‐related psychophysiological variables in healthy medical students experiencing examination stress. Forty volunteers were randomly assigned to either an herbal remedy group (n = 20) or a placebo control group (n = 20). After treatment, systolic blood pressure and plasma concentrations of norepinephrine and cortisol concentrations decreased significantly in the herbal remedy group. The herbal remedy group also exhibited beneficial changes in psychological variables such as anxiety, depression, stress and emotional state. These results suggest that a Korean traditional herbal remedy may reduce systolic blood pressure and catecholamine levels, possibly by stabilizing the sympathetic nervous system. This herbal remedy also reduced the negative psychological symptoms, stress and heightened the emotional state experienced by medical students during examinations. Copyright © 2004 John Wiley & Sons, Ltd.
Biocompatibility of human osteosarcoma cells to root end filling materials
Authors: Huang Tsui Hsien , Yang Chi Chiang , Ding Sinn Jyh , Yan Min , Chou Ming Yung , Kao Chia Tze
Published: September 2004

Ideal root end filling materials should have good physical and chemical properties, and the most important is that the material should be biocompatible with periradicular tissue. The biocompatibility of three root end filling materials, mineral trioxide aggregate, calcium hydroxide‐based cement, and eugenol‐based cement, were investigated in vitro by culturing extracts of these materials with human osteogenic sarcoma cells (U2OS). Extracts of each of the materials were made after incubation of the materials for 1 day and 1 week with complete McCoy's medium. The extracts were serially diluted and then incubated with U2OS cells for 24 and 48 h. Cell survival rates were assessed by means of a viability assay for mitochondrial dehydrogenase activity. Differences in mean cell survival rates were statistically assessed using one‐way ANOVA. Results showed that the survival rates of U2OS cells were largest with mineral trioxide aggregate, followed by calcium hydroxide‐based cement and eugenol‐based cement at 24‐ and 48‐h exposures using the 1‐day and 1‐week extracts. The duration of root end filling material extraction time and treatment time showed variable influence on the survival rates. The results suggest that mineral trioxide aggregate is more biocompatible than the other root end filling materials and is suitable for use in the clinical setting. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 140–145, 2005
Elastic modulus of resin‐based dental restorative materials: A microindentation approach
Authors: Chung S.M. , Yap A.U.J. , Tsai K.T. , Yap F.L.
Published: September 2004

This research aimed to determine the elastic modulus of resin‐based dental composite restoratives using the microindentation test method. Results were then compared with those obtained with the ISO three‐point bending test method. Five materials from the same manufacturer (3M ESPE) were selected for the study. They included microfill (A110), minifill (Z100 and Filtek Z250), poly‐acid modified (F2000), and flowable (Filtek Flowable [FF]) composites. The indentation moduli of the composites were determined using a custom‐designed microindentation test set up after conditioning in water at 37°C for 1 week and 1 month. The indentation test was carried out at peak load of 10Nand Oliver & Pharr's method was used to determine the maximum projected contact area. Data was analyzed using ANOVA/post‐hoc Scheffe's test at significance level 0.05 and Pearson's correlation at significance level 0.01. The mean indentation modulus ranged from 5.80 to 15.64 GPa and 5.71 to 15.35 GPa at 1 week and 1 month, respectively. At both time periods, the indentation modulus of Z100 was significantly higher than all other materials. F2000 was significantly higher than Z250, which was significantly stiffer than A110 and FF. The rankings were in good agreement with the ISO flexural test. A significant, positive, and strong correlation (r= 0.93 and 0.94 at 1 week and 1 month, respectively) in modulus between ISO three‐point bending and microindentation test methods was observed. In view of the small specimen size and good reproducibility, the microindentation reflects a potential test method for determining the elastic properties of dental composite restoratives. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 246–253, 2005
Impact of chemical oxidation on sludge properties and membrane flux in membrane separation bioreactors
Authors: Liao BQ , Catalan LJJ , Droppo IG , Liss SN
Published: September 2004

The effects of sodium hypochlorite (NaOCl) on sludge properties and membrane permeate flux were studied using a pressurized stirred ultrafiltration cell. Oxidation with NaOCl resulted in sludge solubilization and decreased sludge floc sizes. The sludge dissolution constant was estimated at 0.3 ± 0.1 mg sludge mg−1 free chlorine under testing conditions. The increases in soluble chemical oxygen demand and total carbohydrate concentration in centrifuged supernatant were less than proportional to chemical dosage. Membrane permeate fluxes were much lower as a result of oxidation. Soluble biopolymers accounted for more than 76% of the total hydraulic resistance during ultrafiltration of oxidized sludge. By contrast, both the settleable sludge flocs and the soluble biopolymers were important contributors to the hydraulic resistance of sludge before oxidation. Given the benefits of NaOCl solution for membrane cleaning and its negative impact on sludge properties, the quantity of NaOCl solution used for maintenance cleaning of membranes should be optimized. Copyright © 2004 Society of Chemical Industry
Preparation and characterization of UV‐grafted ion‐exchange textiles in continuous electrodeionization
Authors: Yeon Kyeong‐Ho , Song Jung‐Hoon , Kim Jung‐Bae , Moon Seung‐Hyeon
Published: September 2004

Ion‐exchange textiles (IETs) suitable for use in continuous electrodeionization (CEDI) stacks were prepared using the ultraviolet (UV)‐induced grafting of acrylic acid and sodium styrene sulfonate for cation‐exchange textiles, or 2‐hydroxyethyl methacrylate and vinylbenzyl trimethyl ammonium chloride for anion‐exchange textiles, onto nonwoven polypropylene fabric using benzophenone as photoinitiator. Although the ion‐exchange capacity (2.2 meq g−1) of the prepared strong acid cation‐exchange textile was lower than that of IRN77 strong acid cation‐exchange resin (4.2 meq g−1), the overall rate constant of IET was very high due to its low crosslinking and high specific surface area. There was no significant difference between the two different media in terms of the Co(II) removal rate. Furthermore, the current efficiency for IETs was higher than that of IRN77 cation‐exchange resin during a CEDI operation, with efficiencies of 60% and 20%, respectively. The IET also showed the faster exchange kinetics. Therefore, IETs prepared in this study proved to have desirable ion‐conducting characteristics within the CEDI systems. Also this study revealed that the primary removal mechanism in CEDI is the transport of ions through a medium and not the ionic capacity of a medium. Copyright © 2004 Society of Chemical Industry
Requirement of the N‐terminus for dimer formation of phenylalanine‐sensitive 3‐deoxy‐D‐arabino‐heptulosonate synthase AroG of Escherichia coli
Authors: Xu Jianfeng , Hu Changyun , Shen Shuiyuan , Wang Weirong , Jiang Peihong , Huang Weida
Published: September 2004

The first regulatory step in the synthesis of aromatic amino acids is catalyzed by 3‐deoxy‐D‐arabino‐heptulosonate 7‐phosphate synthase (DAHPS). In Escherichia coli, the allosteric DAHPS exists as three isozymes, AroG, AroF and AroH, each independently feedback‐inhibited by corresponding end product amino acids, phenylalanine, tyrosine and typtophan. Structural biological evidences have suggested that the N‐terminus of AroG is involved in the formation of a putative inhibitor‐binding site and feedback inhibition signal transmission. Our previous work showed that a single amino acid residue replacement Ile10Ala or deletion of 15 N‐terminal amino acids could lead to a dramatic loss of AroG enzymatic activity (Hu et al. 2003). Here we demonstrate that the deletion of N‐terminus prevents the enzyme from forming a dimeric structure, indicating that the N‐terminus of AroG plays a critical role in the formation of the essential tight dimeric structure. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Isolation of mak1 from Actinoplanes missouriensis and evidence that Pep2 from Streptomyces coelicolor is a maltokinase
Authors: Jarling Martin , Cauvet Thomas , Grundmeier Matthias , Kuhnert Katharina , Pape Hermann
Published: September 2004

The gene mak1FN coding for maltokinase from Actinoplanes missouriensis is located in a cluster similar to glycogen metabolism clusters identified in Streptomyces coelicolor. Sequence comparisons demonstrate that mak1‐related genes coding for homologous proteins are present in many bacterial genomes including taxonomic distantly related groups such as Rhodospirillales or green sulfur bacteria. More than 50% of the aligned sequences are longer than the mak1 gene from A. missouriensis, and the N‐terminal portion of these putative maltokinases exhibit high sequence homologies with trehalose synthases. A more detailed sequence comparison indicates a relationship of maltokinases to aminoglycoside phospho‐transferases and protein kinases. Transformation of S. lividans with plasmid vectors containing either the mak1 gene from A. missouriensis or the pep2 gene from S. coelicolor resulted in recombinant strains, which produced measurable amounts of maltokinase activity. The proteins Pep2 and Mak1 were over expressed with Streptomyces lividans 66 as a heterologous host and further characterized. The possible physiological function of maltokinases is discussed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of an alkaline‐tolerant cyclodextrin‐metabolizing bacterium and characterization of its cyclodextrinase gene
Authors: Kaulpiboon Jarunee , Rimphanitchayakit Vichien , Pongsawasdi Piamsook
Published: September 2004

Bacillus circulans A11, an alkaline‐tolerant cyclodextrin‐metabolizing bacterium isolated from South‐East Asian soil, was reidentified as Paenibacillus sp. A11 based on 16S rRNA gene sequence comparison, G + C content and cellular fatty acid composition. Levels of similarity of the 16S rRNA gene between strain A11 and the Paenibacillus species were 90–99%, while similarity with Bacillus circulans was only 86%. The major cellular fatty acid was anteiso‐C15:0 which accounted for 59.3% of the total cellular fatty acids and the G+C content was 50.3 mol%. The CDase gene coding for this enzyme was cloned into E. coli. The open reading frame of the CDase gene was 1,959 bp encoding a CDase of 653 amino acid residues. At maximum growth, the specific activity of the recombinant CDase from E. coli was higher than that of Paenibacillus sp. A11. By SDS‐PAGE, the translation product of the recombinant gene showed the same mobility as the purified CDase from the original strain. CDase from both Paenibacillus sp. A11 and E. coli produced glucose and maltose as dominant end‐products of β‐CD hydrolysis. The ratio of maltose to glucose was 1:2. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cloning, characterization and phylogenetic relationships of cel5B, a new endoglucanase encoding gene from Thermobifida fusca
Authors: Posta Katalin , Béki Emese , Wilson David B. , Kukolya József , Hornok László
Published: September 2004

Thermobifida fusca, a thermophilic, aerobic, cellulolytic bacterium has a highly complex cellulase system comprising three endoglucanases, two exoglucanases and one processive endoglucanase. Zymogram analysis indicated that additional cellulases may exist in T. fusca strain TM51, therefore a TM51 expression library was prepared in Streptomyces lividans TK24 and screened for hydrolases. A new endoglucanase gene, named Tf cel5B, was identified. Heterologous Cel5B, produced in S. lividans, had temperature and pH optima of 77 °C and 8.2, respectively and retained more than 60% of its activity after 24 h incubation at 60 °C. Domain analysis revealed an N‐terminal catalytic domain with homology to known endoglucanases in family GH5 and a C‐terminal cellulose binding module III domain (CBD).

Comparing the domain structures of all seven known T. fusca cellulases showed, that the cellulase system of this organism consists of pairs of enzymes from the same GH family, including Cel5A – Cel5B, Cel6A – Cel6B and Cel9A – Cel9B plus a single family GH48 enzyme (Cel48A). Furthermore, the catalytic and substrate binding domains of enzymes, belonging to the same GH family were arranged in opposite orientations. Phylogenetic comparisons of the catalytic domain sequences of the T. fusca cellulases to other family GH5, GH6, GH9 and GH48 cellulases of bacterial origin revealed that the enzyme pairs in the same GH family are not closely related to each other, instead they showed significant similarities to various cellulase enzymes from taxonomically distinct organisms. Therefore, the complex and highly efficient cellulase system of T. fusca seems to be evolved as a result of horizontal gene transfers rather than gene duplication events. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phylogenetic study on Shiraia bambusicola by rDNA sequence analyses
Authors: Cheng Tian‐Fan , Jia Xiao‐Ming , Ma Xiao‐Hang , Lin Hai‐ping , Zhao Yu‐Hua
Published: September 2004

In this study, 18S rDNA and ITS‐5.8S rDNA regions of four Shiraia bambusicola isolates collected from different species of bamboos were amplified by PCR with universal primer pairs NS1/NS8 and ITS5/ITS4, respectively, and sequenced. Phylogenetic analyses were conducted on three selected datasets of rDNA sequences. Maximum parsimony, distance and maximum likelihood criteria were used to infer trees. Morphological characteristics were also observed. The positioning of Shiraia in the order Pleosporales was well supported by bootstrap, which agreed with the placement by Amano (1980) according to their morphology. We did not find significant inter‐hostal differences among these four isolates from different species of bamboos. From the results of analyses and comparison of their rDNA sequences, we conclude that Shiraia should be classified into Pleosporales as Amano (1980) proposed and suggest that it might be positioned in the family Phaeosphaeriaceae. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)