bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and evaluation of a system for running two coexisting Linux systems
Authors: Tabuchi Masaki , Itoh Ken‐Ichi , Nomura Yoshinari , Taniguchi Hideo
Published: April 2007

A method to independently run two coexisting Linux systems on one computer is proposed. Up to the present time a virtual computer method has been used as a method to run multiple operating systems on one computer. This method has a problem, however, in which the guest operating system depends on the running state of the host operating system making it impossible to efficiently utilize the processing performance of each operating system. In contrast to this, because each operating system runs independently in the proposed method by time sharing the processes and exclusively dividing the other hardware resources, one of the operating systems and applications running on the operating systems are not influenced by the other operating system and the applications running on the operating system. This paper presents the proposed method and reports the results of performance evaluations when actually implemented in Linux. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(9): 56– 68, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20343
Application of fingerprint identification technology to systems against inside information leaks and a proposal for its development form
Authors: Kodama Mitsuharu , Umezaki Taizo , Sato Yukio
Published: April 2007

Changes are occurring in the environment surrounding business organizations, such as the development of open networks and flexible migration of employees. In the context of such changes, it has recently been considered more important to prepare measures against information leaks from inside the organization. Among these, an urgent issue in ordinary organizations is to reinforce the existing business system so as to realize highly cost‐effective security functions. This paper considers an actual case of information leakage as a model and systematically summarizes the conditions regarding security functions, based on the views of legal specialists. An actually introduced security system based on fingerprint identification is investigated, and it is shown that practical security measures can be established. A development configuration is then proposed in which part of the security system is placed in a data center and shared by multiple organizations. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(10): 54– 62, 2007; Published online in Wiley InterScience (www.interscience.wiley. com). DOI 10.1002/ecjc.20346
Face detection by generating and selecting features based on Kullback‐Leibler divergence
Authors: Morooka Ken'Ichi , Arakawa Junya , Nagahashi Hiroshi
Published: April 2007

Face detection from images is a complex and nonlinear problem due to the various kinds of face images. This problem is solved by conversion of the original feature vectors extracted from images into high‐dimension feature vectors using nonlinear mapping, and then finding face/nonface discriminant functions in the mapping space. If such discriminant functions are based on the inner products of high‐dimension vectors, such inner products can be easily obtained by substitute calculations of kernel functions in the original feature space. However, in conventional recognition algorithms using kernel functions, numerous features are required to improve recognition accuracy. This paper proposes a new face detection method that uses generation and selection of features on the basis of Kullback‐Leibler divergence (KLD). KLD refers to a distance between the distributions of face and nonface data for certain features. Features with large KLD are used for face detection. Moreover, by evaluating the features based on their KLDs, we can generate new features, and deal with different kinds of features concurrently. In experiments, a classifier designed by the proposed method achieved high recognition performance, while using few features. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(10): 29– 39, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20347
Spin Canting and Topological Ferrimagnetism in Two Manganese(II) Coordination Polymers Generated by In Situ Solvothermal Ligand Reactions
Authors: Cheng Lin , Zhang Wei‐Xiong , Ye Bao‐Hui , Lin Jian‐Bin , Chen Xiao‐Ming
Published: April 2007

Two manganese(II) coordination polymers, [Mn2(bpt)(pa)2(N3)]n [1; Hpa = picolinic acid, Hbpt = 3,5‐bis(2‐pyridyl)‐4H‐1,2,4‐triazole] and [Mn3(ina)2(pa)2(N3)2]n (2; Hina = isonicotinic acid), have been synthesized by solvothermal treatment, in which the ligands bpt and pa were generated in situ by cyclocondensation and hydrolysis of 2‐pyridylamidrazone, respectively. In 1, each binuclear subunit [Mn2(bpt)(N3)] bridged by bpt and N3– ligands is interlinked to four adjacent subunits via four tridentate pa ligands into a diamondoid 3D network, which shows spin‐canting magnetism arising from the lack of inversion centers between the interacting spin centers. In 2, the MnII ions are alternately connected by double μ1,3‐carboxylate/μ1,1‐azide and double μ1,1‐carboxylate bridges into a 1D magnetic chain, which exhibits a topological ferrimagnetic behavior in an antiferromagnetic‐antiferromagnetic‐ferromagnetic sequence. These chains are further interlinked via ina ligands into a 2D network.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Structures of Two New Types of Boronium Salts
Authors: Braun Ulrike , Nöth Heinrich
Published: April 2007

Transamination of di(pyrid‐2‐yl)amine (1) with B(NMe2)3 leads to the isomeric heterocyclic bis(dimethylamino)boryl compound 4 and not to bis(dimethylamino)di(pyrid‐2‐yl)aminoborane (2). B(NMe2)3 reacts with aniline (1:2 ratio) to yield a 1:1 mixture of B(NHPh)3 and (Me2N)2BNHPh. Transamination of this mixture with 1 yields the anilinodimethylamino analogue of 4 (compound 7). Compound 4 reacts with CHCl3 to generate the boronium salt 5 by the abstraction of HCl from CHCl3 and addition of HCl to one of the dimethylamino groups. Compound 5 crystallizes with 4 molecules of CHCl3. Compound 4 is attacked by AlCl3 in toluene to give a mixture of unidentified products from which the tetrachloroaluminate of a new type of spirocyclic diboronium cation, 8, was isolated and characterized by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Tariquidar Analogues: Synthesis by CuI‐Catalysed N/O–Aryl Coupling and Inhibitory Activity against the ABCB1 Transporter
Authors: Egger Michael , Li Xuqin , Müller Christine , Bernhardt Günther , Buschauer Armin , König Burkhard
Published: April 2007

Less lipophilic and better water soluble tariquidar analogues were synthesised from one central anthranilic acid derived building block by CuI‐catalysed N/O–arylation reactions. The compounds were tested for their inhibitory activity against the ABCB1 transporter in a flow cytometric calcein‐AM efflux assay. A correlation between their calculated log P values and their activities was observed, with the more lipophilic analogues being as potent as the reference substance tariquidar.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Cationic Vanadium(IV) Complexes as Efficient Catalysts for Nazarov Cyclizations
Authors: Walz Irene , Bertogg Andreas , Togni Antonio
Published: April 2007

Vanadium(IV) species generated in situ from V(salen)Cl2 complexes (1) by reaction with 2 equiv. of AgSbF6 are effective catalysts for Nazarov cyclizations. Thus, dialkenyl ketones bearing α‐ester groups are efficiently converted to corresponding cyclopentenones in good yields at room temperature, in the presence of 2 mol‐% catalyst. Under such conditions full conversion takes place within minutes for substrates bearing an electron‐donating group at position 1 of the 1,4‐dien‐3‐one system.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of Substituted 1H‐ and 3H‐1‐Benzazepines and Rearrangement of Alkyl 1H‐1‐Benzazepine‐2‐carboxylates into Isoquinolines
Authors: Singh Vijay , Batra Sanjay
Published: April 2007

The SnCl2‐mediated reduction of nitro groups in 2‐nitro‐4‐(2‐nitrobenzylidene)alkanoates and 4‐nitro‐2‐(2‐nitroalkylidene)alkanoates allows the facile synthesis of substituted 1H‐1‐benzazepines and 3H‐1‐benzazepines. This reaction proceeds via SN2′ reaction of ethyl nitroacetate and nitroethane with the acetyl derivatives of Baylis–Hillman adducts deriving from 2‐nitro‐substituted benzaldehydes. During the study, an unprecedented rearrangement of an alkyl 1H‐benzazepine‐2‐carboxylate to a substituted isoquinoline has been observed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Minimizing forced outage risk in generator bidding
Authors: Das Dibyendu , Wollenberg Bruce F.
Published: April 2007

Competition in power markets has exposed the participating companies to physical and financial uncertainties. A random outage after acceptance of bids by the ISO forces a generator to buy power from the real‐time hourly spot market and sell to the ISO at the set day‐ahead market‐clearing price, incurring losses if the real‐time hourly spot market is expensive. This paper assesses the financial risk of the generators using risk profiles and VaRs. A risk minimization module is developed which derives optimum bidding strategies of the generator company such that the estimated total earning is maximized keeping the Value at Risk (VaR) below a tolerable limit. Copyright © 2007 John Wiley & Sons, Ltd.
A novel selectivity technique for high impedance arcing fault detection in compensated MV networks
Authors: Elkalashy Nagy I. , Lehtonen Matti , Darwish Hatem A. , Taalab Abdel‐Maksoud I. , Izzularab Mohamed A.
Published: April 2007

In this paper, the initial transients due to arc reignitions associated with high impedance faults caused by leaning trees are extracted using discrete wavelet transform (DWT). In this way, the fault occurrence is localized. The feature extraction is carried out for the phase quantities corresponding to a band frequency 12.5–6.25 kHz. The detection security is enhanced because the DWT corresponds to the periodicity of these transients. The selectivity term of the faulty feeder is based on a novel technique, in which the power polarity is examined. This power is mathematically processed by multiplying the DWT detail coefficients of the phase voltage and current for each feeder. Its polarity identifies the faulty feeder. In order to reduce the computational burden of the technique, the extraction of the fault features from the residual components is examined. The same methodology of computing the power is considered by taking into account the residual voltage and current detail coefficients where the proposed algorithm performs best. Test cases provide evidence of the efficacy of the proposed technique. Copyright © 2007 John Wiley & Sons, Ltd.
Flexible transmission network planning using the connection number
Authors: Jin Huazheng , Cheng Haozhong
Published: April 2007

Varieties of uncertainties exist in transmission network planning, which directly affects the efficiency and reliability of the planning schemes. Rational expressions of those uncertainties are needed to satisfy the developing power market. In this paper, we present a new method for flexible transmission network planning by introducing the connection number. The connection number is used to represent the synthetic uncertainties of the random, fuzzy and grey ones in the transmission network planning. It can also describe information of both certainty and uncertainty simultaneously, which provides a good match for the reality. A new power flow model of the connection number is presented to obtain the line power flow, and a connection number model (CNM) is developed for the overload analysis, from which the reliable section of the network is obtained. The blind number is defined to describe the flexibility of each reliable section, which is combined with the economics by the cost‐benefit analysis method to evaluate the candidate schemes. In the last section of this paper, two examples are presented on the transmission networks in China to verify the efficiency and reliability of our flexible planning method. Copyright © 2007 John Wiley & Sons, Ltd.
Factor graph based receiver design for PCC‐coded BPSK transmissions over a frequency‐selective fading channel
Authors: Flanagan Mark F. , Fagan Anthony D.
Published: April 2007

This paper presents an iterative receiver to detect and decode parallel concatenated convolutional (PCC) coded BPSK transmissions over a frequency‐selective Rayleigh fading channel. The scheme generalises work by Valenti and Woerner to frequency‐selective channels. A detailed derivation of the receiver from factor graph theory is presented. For the purposes of channel estimation, a Wiener filter based estimator is derived, and the interaction between the channel estimation procedure and the message‐passing algorithm is illustrated. In particular it is shown that, in contrast to Valenti and Woerner's scheme, the pilot symbols appear as variables in the factor graph, leading to the insertion and removal of ‘pilot symbol LLRs’ in the receiver. Finally, the BER performance of the system is demonstrated through computer simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Design issues in the implementation of versatile, high‐speed iterative decoders
Authors: Benedetto Sergio , Dinoi Libero , Montorsi Guido , Tarable Alberto
Published: April 2007

The ever increasing demand for high data rate communication, and the use of radio resource management techniques requiring frame‐by‐frame adaptive coding/modulation to match user demands and channel conditions, pose a number of crucial problems to the design of versatile, high‐speed iterative decoders, for both turbo‐like and low‐density parity‐check codes. Among them, we mention:

The modification of the Soft‐Input Soft‐Output (SISO) algorithm in a way that permits its implementation using several parallel processors working independently on segments of the received frame.

The collisions in the process of reading/writing into/from the memory by the parallel processors.

The design of prunable interleavers covering a wide range of information and/or code words lengths while keeping good spreading properties.

The design of codes yielding a wide range of code rates with good performance for the range of probability of error of interest.

The paper will touch all the previous points, offering state‐of‐the art solutions and examples showing their performance. Copyright © 2007 John Wiley & Sons, Ltd.
Estimating the minimum distance of large‐block turbo codes using iterative multiple‐impulse methods
Authors: Crozier Stewart , Guinand Paul , Hunt Andrew
Published: April 2007

A difficult problem for turbo codes is the efficient and accurate determination of the distance spectrum, or even just the minimum distance, for specific interleavers. This is especially true for large blocks, with many thousands of data bits, if the distance is high. This paper compares a number of recent distance estimation techniques and introduces a new approach, based on using specific event impulse patterns and iterative processing, that is specifically tailored to handle long interleavers with high spread. The new method is as reliable as two previous iterative multiple‐impulse methods, but with much lower complexity. A minimum distance of 60 has been estimated for a rate 1/3, 8‐state, turbo code with a dithered relative prime (DRP) interleaver of lengthK = 65 536. Copyright © 2007 John Wiley & Sons, Ltd.
On the design of rate‐compatible serially concatenated convolutional codes
Authors: Amat Alexandre Graell i , Brännström Fredrik , Rasmussen Lars K.
Published: April 2007

A powerful class of rate‐compatible serially concatenated convolutional codes (SCCCs) has been proposed based on minimising analytical upper bounds on the error probability in the error floor region. In this paper, this class of codes is further investigated by combining analytical upper bounds with extrinsic information transfer chart analysis to improve performance in the waterfall region. Following this approach, we construct a family of rate‐compatible SCCCs with low complexity and good performance in both the error floor and the waterfall regions over a broad range of code rates. The proposed codes outperform standard SCCCs and have a similar performance as more complex parallel concatenated convolutional codes (PCCCs). The proposed codes perform particularly well for high code rates. Copyright © 2007 John Wiley & Sons, Ltd.
Finding distance profiles of unequal error protection block codes
Authors: Bossert Martin , Sidorenko Vladimir , Zyablov Victor
Published: April 2007

We consider distance profiles of arbitrary block codes (over arbitrary alphabets) with unequal error correcting capabilities. We show that for group codes (and hence for codes linear over fields) these distance profiles can be obtained using the well known MaxLog a posteriori probability decoding algorithm. Copyright © 2007 John Wiley & Sons, Ltd.
On genomic coding theory
Authors: Dawy Zaher , Hanus Pavol , Weindl Johanna , Dingel Janis , Morcos Faruck
Published: April 2007

This paper gives a brief overview of several applications from the emerging interdisciplinary field of genomic coding theory that aims at applying concepts and techniques from the field of coding theory to problems from the field of molecular biology. This is motivated by the high precision and robustness found in genomic processes in addition to the increase in the availability of genomic data for a wide range of species. The considered applications include source coding for DNA classification, channel coding for modelling gene expression with emphasis on the process of translation, existence of error correcting codes in the DNA and channel coding structure in the genetic code. Example results are presented that demonstrate the relevance of the proposed approaches and open questions are formulated to suggest future research work. Copyright © 2007 John Wiley & Sons, Ltd.
Estimation of functionals over noisy channels
Authors: Barros João , Tüchler Michael
Published: April 2007

The combination of graphical models and belief propagation algorithms has found wide acceptance in the design of communication systems. We extend the general framework of joint source‐channel decoding on graphs to account for estimation problems in which the goal is not to decode the entire data set but to estimate a function of the transmitted data. This problem is deemed relevant, for example in the context of wireless sensor networks. Copyright © 2007 John Wiley & Sons, Ltd.
Cohen–Merhav bounds on the symbol error rate of uncoded signalling in AWGN interference
Authors: Yousefi Shahram , Holmes Billy
Published: April 2007

Using a recent Bonferroni‐type inequality proposed by Cohen and Merhav, we develop new tight lower bounds on the word error probability of uncoded systems with optimal Maximum A Posteriori (MAP) coherent detection for non‐uniform signalling over additive white Gaussian noise channel. Our results are compared to the state‐of‐the‐art Kuai‐Alajaji‐Takahara (KAT) lower bounds and it is shown that the superiority of one bound to another is dependent on the signal constellation, the amount of non‐uniformity of the Bernoulli source to be communicated and the SNR range of interest. It is noted that bounding techniques for the performance evaluation of communication systems are receiving increasing attention today, thanks to their suitability for a wide variety of schemes ranging from uncoded signalling to space–time‐coded multiple‐input multiple‐output (MIMO) systems. Copyright © 2007 John Wiley & Sons, Ltd.
Digital interference cancellation for DSL using information from the RS decoder
Authors: Toumpakaris Dimitris , Cioffi John M. , Gauthier F. , Zeddam A.
Published: April 2007

One of the factors that affect the performance of Digital Subscriber Loop (DSL) systems is non‐stationary interference, comprising of impulse noise and Radio Frequency Ingress (RFI). In order to achieve reliable transmission, DSL transceivers employ a Forward Error‐Correction scheme that consists of interleaving and Reed–Solomon (RS) encoding. Although RFI typically affects a small area of a symbol in DMT‐based DSL systems, its duration is much longer than that of impulse noise and many DMT symbols are impacted. This leads to increased interleaving and/or RS parity requirements. This paper presents a digital RFI cancellation algorithm for DMT‐based DSL systems. The method exploits information contained in the output of the RS decoder. Under certain conditions it can remove part of the effect of RFI on the received symbols and lead to reduction of the interleaving delay or the RS code parity. The technique does not require any changes at the transmitter and can therefore be incorporated in current DMT‐DSL systems. Copyright © 2007 John Wiley & Sons, Ltd.
Design and performance analysis of a novel trellis coded space–time–frequency OFDM transmission scheme
Authors: Oğuz Onur , Aygölü Ümit , Panayırcı Erdal
Published: April 2007

In this paper a new transmit diversity technique is proposed for wireless communications over frequency selective fading channels. The proposed technique utilises orthogonal frequency division multiplexing (OFDM) to transform a frequency selective fading channel into multiple flat fading subchannels on which first space–frequency coding and then additional space–time coding are applied resulting in a space–time–frequency OFDM (STF‐OFDM) scheme. This scheme provides a quasi‐orthogonal 4 × 4 transmission matrix but relax the constraint on channel fading parameters to be constant over four time or frequency slots into two time and two frequency slots. The pairwise error probability of the new scheme is evaluated and new code design criteria are obtained to improve the error performance. 64‐, 128‐ and 256‐state 4‐PSK trellis codes for STF transmission scheme are generated based on these criteria and their frame error performances in an OFDM system are evaluated by computer simulations. Copyright © 2007 John Wiley & Sons, Ltd.
New quasi‐orthogonal BCH‐derived sequences for CDMA applications
Authors: Ricardo Cesaltina N. E. , Ortigueira Manuel D. , Gerald José António B.
Published: April 2007

Based on two methods recently proposed—the ‘Ranging Criterion’ (RC) and the ‘Generators Ranging Criterion’ (GRC)—new (quasi‐orthogonal) even BCH‐derived sequences are generated which are very attractive for synchronous or quasi‐synchronous Code Division Multiple‐Access (CDMA) systems. Numerical results show that the new family of BCH‐derived sequences can contain a higher number of quasi‐orthogonal sequences with lower correlation values and higher processing gains (PGs) than the spreading sequences typically used in the third generation of mobile communications system, UMTS or in the recent large area synchronised CDMA (LAS‐CDMA) technology. It is shown that the even BCH‐derived sequences are easily generated by a linear shift register generator, allowing the construction of systems with receiver structures of low complexity as compared with those of quasi‐synchronous systems using low correlation zone sequences, as for instance the LAS‐CDMA system. Copyright © 2007 John Wiley & Sons, Ltd.
Joint channel estimation and equalisation of fast time‐varying frequency‐selective channels
Authors: Gligorevic Snjezana
Published: April 2007

This paper addresses joint channel and data estimation for transmission over frequency‐selective and time‐varying channels based on a Doppler‐variant channel impulse response (CIR). A discrete spreading function (DSF), which corresponds to the Doppler Fourier series of the time‐varying channel taps, is introduced. The spectral leakage associated with the Fourier series representation is reduced by oversampling in Doppler‐direction. This approach, however, requires joint channel estimation and equalisation (JCE). Therefore, a recursive least squares (RLS) algorithm for the DSF estimation is combined with the data detection in a reduced state diagram. Furthermore, an enhanced metric, previously introduced in De Broeck et al. (Proceedings of Second International Workshop on Multi‐Carrier Spread‐Spectrum, 1999; published by Kluwer Academic Publishers: Dordrecht, 2000) for time‐invariant channels, is applied here for path selection. The performance of this metric is investigated here for time‐varying and frequency‐selective (TV‐FS) channels. The performance of the proposed approach is compared with the JCE algorithm which uses RLS estimation of a CIR by simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Random direction or random waypoint? A comparison of mobility models for urban environments
Authors: Kraaier Jan , Killat Ulrich
Published: April 2007

The Random Direction (RD) and the Random Waypoint (RWP) mobility models have been discussed extensively in the literature. The focus of this discussion was the stationary distribution of users and speeds of users. In this paper, we extend the investigation to street‐based variants of the two mobility models. We compare statistical properties including user distribution, sojourn times in hotspots and link durations in ad hoc networks. In order to motivate the use of street‐based mobility models, we also perform a comparison with the basic models. Finally, we present our approach to achieve identical user distributions in both street‐based models and investigate the remaining differences, which prove to be negligible for wireless network simulations. Copyright © 2007 John Wiley & Sons, Ltd.
Expansion of cumulant‐based classifier to frequency shift keying modulations and to the use of support vector machines
Authors: Mustafa H. , Doroslovački M.
Published: April 2007

This paper proposes an expansion of the cumulant‐based classifier of digital modulations to frequency shift keying (FSK) modulations. Cumulant estimates are calculated when the FSK modulation is present. The features obtained from the cumulant estimators are used in a support vector machine (SVM) classifier. The performance of the SVM classifier is compared to other classifiers. Among these other classifiers is the cumulant‐based tree classifier which uses thresholds defined by the asymptotic values of the cumulant estimators. The simulation results show that using SVM classifier improves the performance. Copyright © 2007 John Wiley & Sons, Ltd.
Recurrent disruption of the Iμ splice donor site in t(14;18) positive lymphomas : A potential molecular basis for aberrant downstream class switch recombination
Authors: Ruminy Philippe , Jardin Fabrice , Penther Dominique , Picquenot Jean‐Michel , Parmentier Françoise , Buchonnet Gérard , Bertrand Philippe , Tilly Hervé , Bastard Christian
Published: April 2007

t(14;18) positive lymphomas are mature germinal center B‐cell neoplasms. In agreement with this cellular origin, most have somatically mutated immunoglobulin variable genes and the IGH@ locus has almost always been reorganized by class switch recombination (CSR). However, contrasting with normal B‐cells, a majority of cases still express an IgM while the constant genes are normally rearranged only on the non‐productive allele. Concurrently, aberrant intra‐allelic junctions involving downstream switch regions, with a lack of engagement of the switch μ (Sμ), often accumulate on the functional alleles, suggesting some recurrent CSR perturbation during the onset of the disease. To clarify these surprising observations, we addressed the accessibility of the Sμ to the CSR machinery in a large series of patients by characterizing the mutations that are expected to accumulate at this place upon CSR activation. Our data indicate that the Sμ is mutated in a large majority of cases, often on both alleles, indicating that these cells usually reach a differentiation stage where CSR is activated and where this region remains accessible. Interestingly, we also identified a significant cluster of mutations at the splicing donor site of the first exon of the Sμ germline transcripts, on the functional allele. This location suggests a possible relation with CSR perturbations in lymphoma and the clustering points to a probable mechanism of selection. In conclusion, our data suggest that an acquired mutation at the splicing donor site of the Sμ transcripts may participate in the selection of lymphoma cells and play a significant role during the onset of the disease. © 2007 Wiley‐Liss, Inc.
Loss of input from the mossy cells blocks maturation of newly generated granule cells
Authors: Marqués‐Marí Ana‐Isabel , Nacher Juan , Crespo Carlos , Gutièrrez‐Mecinas María , Martínez‐Guijarro Francisco‐José , Blasco‐Ibáñez José‐Miguel
Published: April 2007

The objective of this work is to check whether the input from the mossy cells to the inner molecular layer is necessary for the integration and maturation of the newly generated granule cells of the dentate gyrus (DG) in mice, and if after status epilepticus the sprouting of the mossy fibers can substitute for this projection. Newly generated cells were labeled by administration of 5‐bromo‐deoxyuridine either before or after pilocarpine administration. The neuronal loss in the hippocampus after administration of pilocarpine combined with scopolamine and diazepam seemed restricted to the hilar mossy cells. The maturation of the granule cells was studied using immunohistochemistry for calretinin and NeuN in combination with detection of 5‐bromo‐deoxyuridine. The sprouting of the mossy fibers was detected using Timm staining for zinc‐rich boutons. In normal conditions, granule cells took about 2 weeks to lose the immature marker calretinin. After the loss of the mossy cells, newly generated granule cells remained expressing calretinin for more than a month, until the sprouting of the mossy fibers substituted for the projection of the mossy cells in the inner molecular layer of the DG. Therefore, a proper pattern of connectivity is necessary for the normal development and integration of newly generated granule cells in the adult brain. In a changed environment they cannot adapt transforming in other cell types; simply they are unable to mature. The sprouting of the mossy fibers, although aberrant and a probable source of epileptic activity, may be important for the correct physiology of the granule cells, restoring a likeness of normality in their connective environment. The survival of granule cells incorporated as mature neurons was increased after pilocarpine when compared with normal conditions. Thus, it is likely that the reorganization of the circuitry after the loss of the mossy cells facilitates the survival and incorporation of the newly generated granule cells. © 2007 Wiley‐Liss, Inc.
Rebuilding health systems in post‐conflict countries: estimating the costs of basic services
Authors: Newbrander William , Yoder Richard , Debevoise Anne Bilby
Published: April 2007

After the fall of the Taliban in 2001, the Afghan transitional government and international donors found the health system near collapse. Afghanistan had some of the worst health indicators ever recorded. To begin activities that would quickly improve the health situation, the Ministry of Health (MOH) needed both a national package of health services and reliable data on the costs of providing those services. This study details the process of determining national health priorities, creating a basic package of services, and estimating per capita and unit costs for providing those services, with an emphasis on the costing exercise. Strategies for obtaining a rapid yet reasonably accurate estimate of health service costs nationwide are discussed. In 2002 this costing exercise indicated that the basic package of services could be provided for US$4.55 per person. In 2006, the findings were validated: the four major donors who contracted with non‐governmental organizations (NGOs) to provide basic health services for nearly 80% of the population found per capita costs ranging from $4.30 to $5.12. This study is relevant for other post‐conflict countries that are re‐establishing health services and seeking to develop cost‐effective and equitable health systems. Copyright © 2007 John Wiley & Sons, Ltd.
DNA damage response involves modulation of Ku70 and Rb functions by cyclin A1 in leukemia cells
Authors: Ji Ping , Bäumer Nicole , Yin Taijun , Diederichs Sven , Zhang Feng , Beger Carmela , Welte Karl , Fulda Simone , Berdel Wolfgang E. , Serve Hubert , Müller‐Tidow Carsten
Published: April 2007

Cyclin A1 plays a critical role in hematopoietic malignancies, notably, acute myeloid leukemia. The molecular mechanisms of cyclin A1 action are incompletely understood. Here, we show that cyclin A1 functions are mediated by the retinoblastoma and the Ku70 pathway. High levels of cyclin A1 and the associated CDK2 kinase activity were associated with increasing levels of phosphorylated retinoblastoma in vivo. UV irradiation induced a switch of the CDK2 towards cyclin A1, with accordance to changes in CDK2 kinase activity. The C‐terminus of cyclin A1 directly interacted with Ku70, and DNA binding activity of Ku70 was modulated by cyclin A1/CDK2 and phosphatase treatment. Cyclin A1‐deficiency induced by shRNA increased apoptosis that is induced by DNA damage and death receptor ligands. Taken together, these analyses demonstrate that cyclin A1 exerts antiapoptotic functions by interacting with retinoblastoma and Ku proteins in leukemia cells. © 2007 Wiley‐Liss, Inc.
Salad vegetables dietary pattern protects against HER‐2‐positive breast cancer: A prospective Italian study
Authors: Sant Milena , Allemani Claudia , Sieri Sabina , Krogh Vittorio , Menard Sylvie , Tagliabue Elda , Nardini Elena , Micheli Andrea , Crosignani Paolo , Muti Paola , Berrino Franco
Published: April 2007

Studies investigating the relation of diet to breast cancer have produced conflicting results. We hypothesized that dietary factors associated with breast cancer risk might differentially influence the HER‐2 status of the cancers that develop, and investigated this hypothesis by analyzing the data of the ORDET prospective study. We analyzed 8,861 volunteer women residents of the Varese Province, Italy, for whom we had full data. By December 31, 2001, 238 cases had occurred in which HER‐2 status was known. Four dietary patterns had been identified previously by factor analysis: salad vegetables (high consumption of raw vegetables and olive oil), prudent (cooked vegetables, poultry, fish), western (potatoes, meat, eggs, butter), and canteen (pasta, tomato sauce, wine). In our study, relative risks (RRs) of developing HER‐2‐positive and HER‐2‐negative breast cancers by tertiles of dietary pattern factor scores were assessed by multinomial logistic regression. The salad vegetables dietary pattern had a protective effect against HER‐2‐positive cancers (RR = 0.25, 95% CI 0.10–0.64, for the highest tertile; ptrend = 0.001), much stronger than for HER‐2‐negative cancers (pheterogeneity = 0.039). This important finding that a salad vegetables dietary pattern protects mainly against a specific breast cancer subtype indicates that future studies on environmental/dietary risk factors should explicitly take account of the heterogeneity of breast cancer phenotypes. © 2007 Wiley‐Liss, Inc.
Dietary patterns, the Alternate Healthy Eating Index and plasma sex hormone concentrations in postmenopausal women
Authors: Fung Teresa T. , Hu Frank B. , Barbieri Robert L. , Willett Walter C. , Hankinson Susan E.
Published: April 2007

To evaluate the association between overall diet and sex hormones concentrations, we collected blood from 578 postmenopausal women ages 43 and 69 years in 1989 or 1990. Food intake was measured in 1990 via a food frequency questionnaire. We calculated the Alternate Healthy Eating Index (AHEI), and dietary patterns were identified by factor analysis. The cross‐sectional association between diet and estrogens, sex hormone binding globulin (SHBG) were evaluated with linear regression and adjusted for energy and other potential confounders. We found a higher AHEI score was associated with lower concentrations of estradiol, free estradiol, and higher concentrations of SHBG. The prudent pattern, with higher intakes of fruits, vegetables, and whole grains, was not associated with any sex hormones. The Western pattern, which represents higher intakes of red and processed meats, refined grains, sweets and desserts, was associated with a higher level of estradiol and lower concentrations of SHBG. Further adjustment for BMI attenuated these results except for free estradiol (5th vs. 1st quintile = 0.09 vs. 0.11 pg/mL, p for trend = 0.03). In addition, the AHEI was inversely associated with estradiol among those with BMI > 25, and Western pattern with SHBG among those with BMI < 25. In conclusion, we observed inverse associations between the AHEI score and several estrogens, and it was positively associated with plasma levels of SHBG. In contrast, the Western pattern was positively associated with estrogen levels and inversely with SHBG. However, these associations appeared to be largely accounted for by BMI. © 2007 Wiley‐Liss, Inc.
Global expression profiling of murine MEN1‐associated tumors reveals a regulatory role for menin in transcription, cell cycle and chromatin remodelling
Authors: Mould Arne W. , Duncan Russell , Serewko‐Auret Magdalena , Loffler Kelly A. , Biondi Christine , Gartside Michael , Kay Graham F. , Hayward Nicholas K.
Published: April 2007

Although the identification of menin‐interacting partners and other evidence support a role for menin, the multiple endocrine neoplasia type 1 gene (MEN1) product, in regulating gene expression, little is known about the cellular pathways dysregulated by menin loss during tumorigenesis. The mouse models of MEN1 accurately mimic the human syndrome and provide an opportunity to assess the transcriptional effects of Men1 deletion in different endocrine tumor types to identify common pathway aberrations underlying tumorigenesis in MEN1‐affected tissues. We compared the global gene expression profiles of pituitary adenomas and pancreatic islet tumors with control tissues from wild‐type littermates. Amongst the 551 differentially expressed genes was significant over‐representation of genes associated with chromatin remodelling, transcription and cell cycling, including some genes known to encode menin‐binding partners, e.g., Rhox5 and Mll1. Consistent with increased cell‐cycle transition from G1 to S phase was an elevation of Cdc7 expression in the tumors, which was confirmed by qRT‐PCR using independent samples. In support of previous findings in islet tumors, we found down‐regulation of the cell‐cycle regulator, p18, in both the pancreatic islet and pituitary adenomas, suggesting that reduced p18 levels may be important for Men1‐related tumorigenesis in multiple tissues. Surprisingly, we identified increased p16 transcript in pancreatic islet and pituitary tumors. This was accompanied by increased cytoplasmic localization p16 protein in tumor cells. The specific genes and general pathways we have found to be commonly dysregulated in MEN1 tumors, provide a platform for determining their roles in endocrine tumorigenesis. © 2007 Wiley‐Liss, Inc.
Co‐twin control and cohort analyses of body mass index and height in relation to breast, prostate, ovarian, corpus uteri, colon and rectal cancer among Swedish and Finnish twins
Authors: Lundqvist Ellen , Kaprio Jaakko , Verkasalo Pia K. , Pukkala Eero , Koskenvuo Markku , Söderberg Karin C. , Feychting Maria
Published: April 2007

Associations between anthropometric measures and cancer have been studied previously, but relatively few studies have had the opportunity to control for genetic and early shared environmental factors. In this study, we analyzed 2 twin cohorts from Sweden born 1886–1925 (n = 21,870) and 1926–1958 (n = 30,279) and 1 from Finland born 1880–1958 (n = 25,882) including in total 78,031 twins, and studied the association between BMI and height and risk of prostate, breast, ovarian, corpus uteri, colon and rectal cancer. The cohorts were both analyzed through a co‐twin control method and as traditional cohorts. In co‐twin control analyses, older obese (BMI ≥ 30 kg/m2) subjects (median age 56 years at baseline) were at higher risk of cancer of the corpus uteri (OR = 3.0; 95% CI 0.9–10.6), colon (OR = 1.9; 95% CI 0.8–4.5) and breast (OR = 2.5; 95% CI 1.3–4.2). For younger obese women (median age 30 years at baseline), an inverse tendency was observed for breast cancer (OR = 0.6; 95% CI 0.3–1.5, p for trend = 0.05). The tallest women had an increased risk of breast (OR = 1.8; 95% CI 1.3–2.7) and ovarian cancer (OR = 1.7; 95% CI 0.8–3.5). No consistent associations were found for prostate cancer either for BMI or height. There are some suggestions in our study that uncontrolled genetic or early shared environmental factors may affect risk estimates in studies of anthropometric measures and cancer risk, but do not explain observations of increased cancer risks related to BMI or height. © 2007 Wiley‐Liss, Inc.
Biocompatibility evaluation of crosslinked chitosan hydrogels after subcutaneous and intraperitoneal implantation in the rat
Authors: Azab Abdel Kareem , Doviner Victoria , Orkin Boris , Kleinstern Jackie , Srebnik Morris , Nissan Aviram , Rubinstein Abraham
Published: April 2007

The aim of the present study was to evaluate the toxicity of biodegradable hydrogels in the rat with a future aim of utilizing this hydrogel as a vehicle for brachytherapy delivery in cancer patients. Two types of chitosan hydrogels: fast degrading and slow degrading; were prepared and surgically implanted in rats. The adjacent tissue response to the gels after subcutaneous and intraperitoneal implantation was examined histologically and found to be identical to typical foreign body response and was milder than the response to absorbable surgical sutures (Vicril®). Neither tissue damage nor gel fragments could be detected in distant organs (brain, heart, lungs, liver, spleen, kidney, and sternal bone marrow) after implantation of the hydrogels. The degradation mechanism of the gels was studied invivo, and it was deduced that an oxidative process degraded the chitosan. Loading the hydrogels with a radioisotope (131I‐norcholesterol) caused a severe tissue response and necrosis in adjacent tissues only at a distance of several microns. It is concluded that crosslinked chitosan implants could serve as alternative, biocompatible, and safe biodegradable devices for radioisotope delivery in brachytherapy for cancer. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007.
Regulation of endothelial cell function by GRGDSP peptide grafted on interpenetrating polymers
Authors: Patel Shyam , Tsang Jonathan , Harbers Gregory M. , Healy Kevin E. , Li Song
Published: April 2007

Vascular endothelium plays an important role in preventing thrombogenesis. Bioactive molecules such as fibronectin‐derived peptide Gly‐Arg‐Gly‐Asp‐Ser‐Pro (GRGDSP) can be used to modify the surface of cardiovascular implants such as vascular grafts to promote endothelialization. Here we conjugated GRGDSP peptide to the nonfouling surface of an interpenetrating polymer network (IPN), and investigated the effects of the immobilized GRGDSP molecules on EC functions under static and flow conditions at well‐defined GRGDSP surface densities (∼0 to 3 pmol/cm2). EC adhesion and spreading increased with GRGDSP surface density, reached a plateau at 1.5 pmol/cm2, and increased further beyond 2.8 pmol/cm2. Cell adhesion and spreading on GRGDSP induced two waves of extracellular signal‐regulated kinase (ERK) activation, and 0.2 pmol/cm2 density of GRGDSP was sufficient to activate ERK. EC proliferation rate was not sensitive to GRGDSP surface density, suggesting that cell spreading at low‐density of GRGDSP is sufficient to maintain EC proliferation. EC migration on lower‐density GRGDSP‐IPN surfaces was faster under static condition. With the increase of GRGDSP density, the speed and persistence of EC migration dropped quickly (0.2–0.8 pmol/cm2) and reached a plateau, followed by a slower and gradual decrease (1.5–3.0 pmol/cm2). These data suggest that the changes of EC functions were more sensitive to the increase of GRGDSP density at lower range. Under flow condition with shear stress at 12 dyn/cm2, EC migration was inhibited on GRGDSP‐IPN surfaces, which may be attributed to the assembly of large focal adhesions induced by shear stress, suggesting a catch‐bond characteristic for RGD‐integrin binding. This study provides a rational base for surface engineering of cardiovascular implants. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007.
Monomer conversion and cytotoxicity of dental composites irradiated with different modes of photoactivated curing
Authors: Tseng Wan‐Yu , Huang Chien‐Hsun , Chen Ruey‐Song , Lee Ming‐Shu , Chen Yi‐Jane , Rueggeberg Frederick A. , Chen Min‐Huey
Published: April 2007

The aim of the study was to compare the monomer conversion and cytotoxicity of two resin composites, Tetric Ceram (TC) and Heliomolar (HM), irradiated with a halogen light‐curing unit (Optilux 501) using a number of curing modes, boost (OB), ramp (OR), and conventional (OC), as well as a light‐emitting diode (LED) curing unit (LEDemetron; LEDe). The effects of irradiation times (10, 20, 30, and 40 s) were also investigated. The monomer conversion of resin composites was measured using Fourier transform infrared (FTIR) analysis. Resin samples were preimmersed in Dulbeco's modified engles medium (DMEM) for 24 h, and the periodontal ligament cells (PDL) were cultured with aged medium for 72 h to evaluate the cytotoxic effects of resin samples using the microtiter‐tetrazolium (MTT) method. The spectral outputs of the curing units were also compared. After irradiation using the same curing mode, the TC monomer conversion was higher than the HM analog. The TC conversion value was lower after OC and LEDemetron irradiation for 10 s compared to exposures of 30 and 40 s. The HM conversion value was lowest for the 10‐s OC irradiation, and highest for the 40‐s OC exposure. In cytotoxicity tests, the negative control group was without irradiation. The succinate dehydrogenase (SDH) activities of the OB and OR‐irradiated TC samples were significantly lower than analogs irradiated with LEDemetron for 40 s; however, no significant differences were demonstrated between OB, OR, and control groups. Further, no significant differences in SDH activity were demonstrated for OB, OR, and control groups of the HM. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2007
Strontium‐substituted apatite coating grown on Ti6Al4V substrate through biomimetic synthesis
Authors: Oliveira A. L. , Reis R. L. , Li P.
Published: April 2007

During the last few years Strontium has been shown to have beneficial effects when incorporated at certain doses in bone by stimulating bone formation. It is believed that its presence locally at the interface between an implant and bone will enhance osteointegration and therefore, ensure the longevity of a joint prosthesis. In this study we explore the possibility of incorporating Sr into nano‐apatite coatings prepared by a solution‐derived process according to an established biomimetic methodology for coating titanium based implants. The way this element is incorporated in the apatite structure and its effects on the stereochemistry and morphology of the resulting apatite layers was investigated, as well as its effect in the mineralization kinetics. By using the present methodology it was possible to incorporate increasing amounts of Sr in the apatite layers. Sr was found to incorporate in the apatite layer through a substitution mechanism by replacing Ca in the apatite lattice. The presence of Sr in solution induced an inhibitory effect on mineralization, leading to a decrease in the thickness of the mineral layers. The obtained Sr‐substituted biomimetic coatings presented a bone‐like structure similar to the one found in the human bone and therefore, are expected to enhance bone formation and osteointegration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2007