bluuebunny/crossref_metadata_2025 huggingface dataset:
Building reliable and efficient data transfer and processing pipelines
Authors: Kosar T. , Kola G. , Livny M.
Published: November 2005

Scientific distributed applications have an increasing need to process and move large amounts of data across wide area networks. Existing systems either closely couple computation and data movement, or they require substantial human involvement during the end‐to‐end process. We propose a framework that enables scientists to build reliable and efficient data transfer and processing pipelines. Our framework provides a universal interface to different data transfer protocols and storage systems. It has sophisticated flow control and recovers automatically from network, storage system, software and hardware failures. We successfully used data pipelines to replicate and process three terabytes of DPOSS astronomy image dataset and several terabytes of WCER educational video dataset. In both cases, the entire process was performed without any human intervention and the data pipeline recovered automatically from various failures. Copyright © 2005 John Wiley & Sons, Ltd.
A Grid service broker for scheduling e‐Science applications on global data Grids
Authors: Venugopal Srikumar , Buyya Rajkumar , Winton Lyle
Published: November 2005

The next generation of scientific experiments and studies, popularly called e‐Science, is carried out by large collaborations of researchers distributed around the world engaged in the analysis of huge collections of data generated by scientific instruments. Grid computing has emerged as an enabler for e‐Science as it permits the creation of virtual organizations that bring together communities with common objectives. Within a community, data collections are stored or replicated on distributed resources to enhance storage capability or the efficiency of access. In such an environment, scientists need to have the ability to carry out their studies by transparently accessing distributed data and computational resources. In this paper, we propose and develop a Grid broker that mediates access to distributed resources by: (a) discovering suitable data and computational resources sources for a given analysis scenario; (b) optimally mapping analysis jobs to resources; (c) deploying and monitoring job execution on selected resources; (d) accessing data from local or remote data sources during job execution; and (e) collating and presenting results. The broker supports a declarative and dynamic parametric programming model for creating Grid applications. We have used this model in Grid‐enabling a high‐energy physics analysis application (the Belle Analysis Software Framework). The broker has been used in deploying Belle experimental data analysis jobs on a Grid testbed, called the Belle Analysis Data Grid, having resources distributed across Australia interconnected through GrangeNet. Copyright © 2005 John Wiley & Sons, Ltd.
Long‐Lived Charge‐Transfer States in Compact Donor–Acceptor Dyads
Authors: Verhoeven Jan W. , van Ramesdonk Hendrik J. , Groeneveld Michiel M. , Benniston Andrew C. , Harriman Anthony
Published: November 2005

Photoinduced electron transfer is a widely applied method to convert photon energy into a useful (electro)chemical potential, both in nature and in artificial devices. There is a continuing effort to develop molecular systems in which the charge‐transfer state, populated by photoinduced electron transfer, survives sufficiently long to tap the energy stored in it. In general this has been found to require the construction of rather complex molecular systems, but more recently a few approaches have been reported that allow the use of much more simple and relatively small electron donor–acceptor dyads for this purpose. The most successful examples of such systems seem to be those that apply “electron spin control” to slow down the spontaneous decay of the charge‐transfer state, and these are reviewed in this minireview, with a discussion of the underlying principles and a critical evaluation of some of the claims made with regard to using a pronounced “inverted‐region effect” as an alternative method to prolong the lifetime of charge‐transfer states.
From Colloidal Co/CoO Core/Shell Nanoparticles to Arrays of Metallic Nanomagnets: Surface Modification and Magnetic Properties
Authors: Wiedwald Ulf , Fauth Kai , Heßler Markus , Boyen Hans‐Gerd , Weigl Frank , Hilgendorff Michael , Giersig Michael , Schütz Gisela , Ziemann Paul , Farle Michael
Published: November 2005

The magnetic properties of nanoparticles can be subject to strong variations as the chemical composition of the particle surface is modified. To study this interrelation of surface chemistry and magnetism, self‐assembled layers of colloidal 9.5 nm Co/CoO core/shell nanoparticles were exposed to mild reactive hydrogen and oxygen plasmas. The consecutive oxygen/hydrogen plasma treatment transforms the particle layer into an array of metallic nanomagnets with complete reduction of the oxide and removal of the organic surfactants. The original arrangement of the particle array and the number of Co atoms per particle remains unchanged within the experimental error, and thus this is a possible route for the fabrication of ultrahigh‐density magnetic bit structures from colloidal dispersions. The magnetic properties can be tuned by controlling the thickness of the surface oxide layer, which magnetically hardens the particles, as evidenced by element‐specific magnetic hysteresis loops.
Identifiability of Models for Fluorescence Quenching in Aqueous Micellar Systems
Authors: Boens Noël , Van der Auweraer Mark
Published: November 2005

The first deterministic identifiability analysis is presented for four commonly used kinetic models of fluorescence quenching of an excited probe in aqueous micelles: A) model with immobile quenchers, B) model with mobile quenchers, C) an extension of model B in which exchange of quenchers both via the aqueous phase and during micelle collisions is taken into account, and D) model with probe migration. It is shown that these specific models for fluorescence decay of an excited probe solubilized in a micelle and quenched by molecules or ions that are Poisson‐distributed over the micelles, resulting in the generalized four‐parameter equation f(t)=A1 exp{−A2t−A3[1−A4t]}, are uniquely identifiable in terms of four descriptive A parameters. Moreover, each model also can be uniquely identified in terms of the underlying rate constants and micellar concentration or mean micellar aggregation number. This means that these parameters can be extracted in a unique way from time‐resolved fluorescence quenching experiments on a probe in micelles. For each model the recommended analysis approach is given.
Artificial Photosynthetic Reaction Centers: Mimicking Sequential Electron and Triplet‐Energy Transfer
Authors: Palacios Rodrigo E. , Kodis Gerdenis , Gould Stephanie L. , de la Garza Linda , Brune Alicia , Gust Devens , Moore Thomas A. , Moore Ana L.
Published: November 2005

An artificial photosynthetic reaction center consisting of a carotenoid (C), a dimesitylporphyrin (P), and a bis(heptafluoropropyl)porphyrin (PF), C‐P‐PF , and the related triad in which the central porphyrin has been metalated to give C‐PZn‐PF have been synthesized and characterized by transient spectroscopy. These triads are models for amphipathic triads having a carboxylate group attached to the PF moiety; they are designed to carry out redox processes across lipid bilayers. Triad C‐P‐PF undergoes rapid singlet–singlet energy transfer between the porphyrin moieties, so that their excited states are in equilibrium. In benzonitrile, photoinduced electron transfer from the first excited singlet state of P and hole transfer from the first excited singlet state of PF yield the initial charge‐separated state C‐P.+‐PF.−. Subsequent hole transfer to the carotenoid moiety generates the final charge‐separated state C.+‐P‐PF.−, which has a lifetime of 1.1 μs and is formed with a quantum yield of 0.24. In triad C‐PZn‐PF energy transfer from the PZn excited singlet to the PF moiety yields C‐PZn‐1PF . A series of electron‐transfer reactions analogous to those observed in C‐P‐PF generates C.+‐PZn‐PF.−, which has a lifetime of 750 ns and is formed with a quantum yield of 0.25. Flash photolysis experiments in liposomes containing an amphipathic version of C‐PZn‐PF demonstrate that the added driving force for photoinduced electron transfer in the metalated triad is useful for promoting electron transfer in the low‐dielectric environment of artificial biological membranes. In argon‐saturated toluene solutions of C‐P‐PF and C‐PZn‐PF , charge separation is not observed and a considerable yield of triplet species is generated upon excitation of the porphyrin moieties. In both triads triplet energy localized in the PF moiety is channeled to the carotenoid chromophore by a triplet energy‐transfer relay mechanism. Certain photophysical characteristics of these triads, including the sequential electron transfer and the triplet energy‐transfer relay mechanism, are reminiscent of those observed in natural reaction centers of photosynthetic bacteria.
Patterns with High Rhythmicity Levels in Multicomponent Liesegang Systems
Authors: Msharrafieh Maysam , Sultan Rabih
Published: November 2005

Liesegang banding is the display of rhythmic strata of precipitate as co‐precipitate ions interdiffuse in a gel medium. Complex periodic patterns as well as aperiodic structures could emerge, notably in systems where more than one salt is precipitated. The use of three cations (Co2+, Ni2+, and Mg2+) in the banded precipitation of their hydroxides resulted in an unusual pattern with a consistently increasing rhythmicity. A periodic structure marked by the succession of band multiplets with increasing number of bands (from singlets to doublets to triplets to quadruplets, consistently) was observed. Such rhythmic patterns are obtained as the initial Mg2+concentration ([Mg2+]0), chosen as a control parameter, increases through a critical value. At high [Mg2+]0, the trend breaks after a long time elapses. Two types of bifurcation are therefore experienced by such a system: concentration bifurcation and diffusive (time/space) bifurcation. The dynamics is elucidated on the basis of an analysis of the bands in certain groups, and gel regions between these groups, as well as between group blocs (here, a bloc denotes a succession of multiplet groups, with repetitively the same number of bands). Finally, similarities between our system and naturally occurring rhythmic patterns are emphasized and discussed.
Synchrotron Radiation Circular Dichroism Spectroscopy of Ribose and Deoxyribose Sugars, Adenosine, AMP and dAMP Nucleotides
Authors: Nielsen Steen Brøndsted , Chakraborty Tapas , Hoffmann Søren Vrønning
Published: November 2005

Synchrotron radiation circular dichroism (SRCD) spectra of ribose and deoxyribose sugars, adenosine, AMP and dAMP nucleotides and cyclic derivatives were measured in the vacuum ultraviolet region (down to 168 nm for sugars and 175 nm for adenine derivatives) and at different pH values (3, 6–7, 9–10) and temperatures (between 5 and 45 °C). The information content in the VUV region is important since the CD bands strongly depend on the chemical structure of the sugar, the presence and orientation of a phosphate group and the protonation state of adenine. On the other hand, single or double deprotonation of the phosphoric acid group has no influence on the spectra. We assign the vacuum ultraviolet (VUV) CD bands of the nucleoside and nucleotides to be due mainly to n→π* transitions in the adenine nucleobase based on a comparison with the absorption spectra. The CD bands of the sugars are due to n(O →σ*) transitions and are much smaller than the CD signal from the nucleotides in the VUV region. Bands are assigned to both pyranose and open‐chain forms.
Scanning Tunneling Microscopy and Spectroscopy of Donor–Acceptor–Donor Triads at the Liquid/Solid Interface
Authors: Uji‐i Hiroshi , Miura Atsushi , Schenning Albert , Meijer E. W. , Chen Zhijian , Würthner Frank , De Schryver Frans C. , Van der Auweraer Mark , De Feyter Steven
Published: November 2005

By means of scanning tunneling microscopy (STM), the self‐assembly of two organic donor–acceptor–donor triads (donor=oligo(p‐phenylene vinylene) (OPV); acceptor=perylene diimide (PDI)) and their mixtures has been investigated at the liquid/solid interface. Both triads differ in the nature of the substituents and, therefore, in the redox properties of the central perylene diimide unit (H or Cl). Thanks to the submolecular resolution, the distinct electronic properties of the units, within a triad and between the two triads, are reflected by the relative STM contrast in the bias‐dependent imaging experiments. Moreover, scanning tunneling spectroscopy reveals an inverse rectifying behavior of the OPV and H‐substituted PDI units, which is discussed in the framework of quasi‐resonant tunneling. A striking difference is observed for the Cl‐substituted triad.
Ultrafast Intramolecular Charge Transfer and Internal Conversion with Tetrafluoro‐aminobenzonitriles
Authors: Galievsky Victor A. , Druzhinin Sergey I. , Demeter Attila , Jiang Yun‐Bao , Kovalenko Sergey A. , Pérez Lustres Luis , Venugopal Karunakaran , Ernsting Nikolaus P. , Allonas Xavier , Noltemeyer Mathias , Machinek Reinhard , Zachariasse Klaas A.
Published: November 2005

The five 2,3,5,6‐tetrafluoro‐4‐aminobenzonitriles XABN4F with a dimethyl‐amino (DMABN4F), diethyl‐amino (DEABN4F), azetidinyl (AZABN4F), methyl‐amino (MABN4F) or amino (ABN4F) group undergo ultrafast intramolecular charge transfer (ICT) at room temperature, in the polar solvent acetonitrile (MeCN) as well as in the nonpolar n‐hexane. ICT also takes place with the corresponding non‐fluorinated aminobenzonitriles DMABN, DEABN and AZABN in MeCN, whereas for these molecules in n‐hexane only minor (DMABN, DEABN) or no (AZABN) ICT fluorescence is detected. For the secondary (MABN) and primary (ABN) amines, an ICT reaction does not occur, which makes ABN4F the first electron donor/acceptor molecule with an NH2 group for which ICT is observed. The ICT state of the XABN4Fs has a dipole moment of around 14 D, clearly smaller than that of DMABN (17 D). This difference is attributed to the electron withdrawing from the CN group to the phenyl ring, exerted by the four F‐substituents. The reaction from the initially prepared locally excited (LE) to the ICT state in n‐hexane proceeds in the sub‐picosecond time range: 0.35 ps (DMABN4F), 0.29 ps (DEABN4F) and 0.13 ps (AZABN4F), as determined from femtosecond transient absorption measurements. In the highly polar solvent MeCN, an ICT reaction time of around 90 fs is observed for all five XABN4Fs, irrespective of the nature of their amino group. This shows that with these molecules in MeCN the ICT reaction rate is limited by the solvent dielectric relaxation time of MeCN, for which a value of around 90 fs has been reported. It is therefore concluded that, during this ultrashort ICT reaction, a large‐amplitude motion such as a full 90° twist of the amino group is unlikely to occur in the XABN4Fs. The ICT state of the XABN4Fs is strongly quenched via internal conversion (IC), with a lifetime ${{\rm{\tau }}\prime _0 (ICT)}$ down to 3 ps, possibly by a reaction passing through a conical intersection made accessible due to a deformation of the phenyl group by out‐of‐plane motions induced by vibronic coupling between low‐lying πσ* and ππ* states in the XABN4Fs.
DFT Study of Fullerene Dimers
Authors: Bihlmeier Angela , Samson Claire C. M. , Klopper Wim
Published: November 2005

Several [2+2] dimerization products of a fullerene Cn (n=50, 52, 54, 56, 58, 60) in its most stable form are presented and discussed. In total, 34 dimers are studied. Only symmetric CnCn dimers (no mixed products) are reported, and only dimers of the fullerenes C50 to C58 with bonds between C atoms in adjacent pentagons are considered. Geometries were optimized within the framework of density functional theory using the Becke–Perdew exchange‐correlation functional (BP86) in combination with an empirical dispersive energy correction, which contributes significantly to the binding energy. The results are discussed in the context of the reactivity of adjacent pentagon sites. The lateral interaction between fullerenes is found to be stronger for C50 to C58 than for C60, which is consistent with recent experimental observations. Further, the possibility of polymer formation based on the investigated [2+2] reaction is addressed.
Enhancement of Förster Energy Transfer within a Microspherical Cavity
Authors: Fujiwara Hideki , Sasaki Keiji , Masuhara Hiroshi
Published: November 2005

Energy transfer from pyrene to perylene molecules co‐doped within a poly(methyl methacrylate) latex microsphere was drastically accelerated relative to free space. Fluorescence spectra of the microspheres showed that the relative emission intensities of pyrene and perylene changed with the sphere diameter. Analyses of emission decay profiles clarified that Förster‐type energy‐transfer processes were induced and that the transfer rates increased within the microspherical cavity. This enhancement can be ascribed not only to the quantum electrodynamic effects on the pyrene emission rate, but also the cavity effect of increasing the overlapping factor between donor emission and acceptor absorption spectra.
Ultrafast Electron Diffraction: Dynamical Structures on Complex Energy Landscapes
Authors: Shorokhov Dmitry , Park Sang Tae , Zewail Ahmed H.
Published: November 2005

In this contribution, we report studies in ultrafast electron diffraction (UED), with the aim of exploring new directions. The main focus is on the determination of complex structures and their dynamics with spatial and temporal resolutions sufficient to give an atomic‐scale picture for the evolution in chemical or biological change. We also provide the theoretical framework for UED, and compare the experimental findings of UED to those predicted by density functional and charge density calculations. Selected applications are given in order to highlight phenomena related to concepts such as bifurcation of trajectories in dynamics, far‐from‐equilibrium coherent structures, and conformational robustness in biological structures. For the former two cases, we consider chemical systems, and, for the latter, we examine proteins of 200 atoms (angiotensin I) or more.
Ultrafast Electron Diffraction: Oriented Molecular Structures in Space and Time
Authors: Baskin J. Spencer , Zewail Ahmed H.
Published: November 2005

The technique of ultrafast electron diffraction allows direct measurement of changes which occur in the molecular structures of isolated molecules upon excitation by femtosecond laser pulses. The vectorial nature of the molecule–radiation interaction also ensures that the orientation of the transient populations created by the laser excitation is not isotropic. Here, we examine the influence on electron diffraction measurements—on the femtosecond and picosecond timescales—of this induced initial anisotropy and subsequent inertial (collision‐free) molecular reorientation, accounting for the geometry and dynamics of a laser‐induced reaction (dissociation). The orientations of both the residual ground‐state population and the excited‐ or product‐state populations evolve in time, with different characteristic rotational dephasing and recurrence times due to differing moments of inertia. This purely orientational evolution imposes a corresponding evolution on the electron scattering pattern, which we show may be similar to evolution due to intrinsic structural changes in the molecule, and thus potentially subject to misinterpretation. The contribution of each internuclear separation is shown to depend on its orientation in the molecular frame relative to the transition dipole for the photoexcitation; thus not only bond lengths, but also bond angles leave a characteristic imprint on the diffraction. Of particular note is the fact that the influence of anisotropy persists at all times, producing distinct differences between the asymptotic “static” diffraction image and the predictions of isotropic diffraction theory.
Performance of Fluorescence Correlation Spectroscopy for Measuring Diffusion and Concentration
Authors: Enderlein Jörg , Gregor Ingo , Patra Digambara , Dertinger Thomas , Kaupp U. Benjamin
Published: November 2005

Fluorescence correlation spectroscopy (FCS) has become an important tool for measuring diffusion, concentration, and molecular interactions of cellular components. The interpretation of FCS data critically depends on the measurement set‐up. Here, we present a rigorous theory of FCS based on exact wave‐optical calculations. Six of the most important optical and photophysical factors that influence FCS are studied: fluorescence anisotropy, cover‐slide thickness, refractive index of the sample, laser‐beam geometry, optical saturation, and pinhole adjustment. Our theoretical framework represents a general attempt to link all relevant parameters of the experimental set‐up with the measured correlation function.
Adaptive cross‐layer bandwidth allocation in a rain‐faded satellite environment
Authors: Celandroni Nedo , Davoli Franco , Ferro Erina , Gotta Alberto
Published: November 2005

Two control schemes, based on cross‐layer adaptation and a hierarchical parametric optimization of the bandwidth allocation, are described and investigated in a satellite network environment, in the presence of both real‐time and best‐effort traffic flows. A number of earth stations (traffic stations) operate in different weather conditions, with different levels of fade, which affect the transmitted signals. The call admission control policy for real‐time connections is administered locally at the traffic stations. Amaster stationis charged to manage the time division multiple access bandwidth allocation policy, by defining bandwidth partitions to the traffic stations. Upon detecting significant fade changes, the signalling from the traffic stations triggers new bandwidth redistributions. The control schemes are compared, and the effect of fade countermeasures, applied at the physical layer, on the bandwidth occupation is explicitly accounted for. For each policy, figures of merit such as loss, blocking and dropping probabilities are computed for a specific real environment, based on the Italsat satellite national coverage payload characteristics. Copyright © 2005 John Wiley & Sons, Ltd.
Managing QoS requirements for video streaming: from intra‐node to inter‐node
Authors: Bai Y. , R. Ito M.
Published: November 2005

Streaming video over IP networks has become increasingly popular; however, compared to traditional data traffic, video streaming places different demands on quality of service (QoS) in a network, particularly in terms of delay, delay variation, and data loss. In response to the QoS demands of video applications, network techniques have been proposed to provide QoS within a network. Unfortunately, while efficient from a network perspective, most existing solutions have not provided end‐to‐end QoS that is satisfactory to users. In this paper, packet scheduling and end‐to‐end QoS distribution schemes are proposed to address this issue. The design and implementation of the two schemes are based on the active networking paradigm. In active networks, routers can perform user‐driven computation when forwarding packets, rather than just simple storing and forwarding packets, as in traditional networks. Both schemes thus take advantage of the capability of active networks enabling routers to adapt to the content of transmitted data and the QoS requirements of video users. In other words, packet scheduling at routers considers the correlation between video characteristics, available local resources and the resulting visual quality. The proposed QoS distribution scheme performs inter‐node adaptation, dynamically adjusting local loss constraints in response to network conditions in order to satisfy the end‐to‐end loss requirements. An active network‐based simulation shows that using QoS distribution and packet scheduling together increases the probability of meeting end‐to‐end QoS requirements of networked video. Copyright © 2005 John Wiley & Sons, Ltd.
Efficient medium arbitration of FSAN‐compliant GPONs
Authors: Leligou H. C. , Linardakis Ch. , Kanonakis K. , Angelopoulos J. D. , Orphanoudakis Th.
Published: November 2005

The steadily rising demand for multimedia and data services, the falling cost and omnipresence of Ethernet and the maturity of passive optical networks (PON) technology, promise to radically change the landscape in the local loop. The heart of a gigabit PON system (recently standardized by FSAN/ITU) is the medium access controller (MAC), which arbitrates access to the upstream link among users with fluctuating traffic demands and effects the multiplexing and concentration policy. At the same time, it has to safeguard the service quality and enforce the parameters agreed in the service level agreements (SLAs) between the users and the service provider. In this paper, a MAC protocol designed to serve any mix of services according to their quality of service (QoS) needs, employing four priority levels along with a high number of logically separate data queues is presented. The architecture and implementation in hardware of a MAC algorithm capable of allocating bandwidth down to a resolution of a byte with QoS differentiation is the focus of this paper. It employs the bandwidth arbitration tools of the FSAN/ITU G.984.3 standard and maps SLA parameters to GPON service parameters to create an efficient, fair and flexible residential access system. Copyright © 2005 John Wiley & Sons, Ltd.
It's not that bad: Error introduced by oral stimulants in salivary cortisol research
Authors: Talge Nicole M. , Donzella Bonny , Kryzer Erin M. , Gierens Andrea , Gunnar Megan R.
Published: November 2005

Evidence that oral stimulants can produce interference effects in salivary cortisol assays has led to advice to avoid their use. However, in studies with young children, the use of these saliva‐producing substances increases compliance with collection procedures. Four experiments are described to examine the effects of two commonly used stimulants, SweetTarts™ and Koolaid™. Across these experiments, interference effects produced by different quantities of these stimulants (0.025, 0.1, and 0.2 g) and those produced in two commonly used assays, DELFIA and EIA, were explored. The impact of using cotton rolls soaked with an oral stimulant prior to saliva collection was also examined. In general, oral stimulants did not affect the rank ordering of cortisol values, as the results for stimulant‐treated samples were highly correlated with those of untreated samples (approximately .90 for serially collected samples and .95 for aliquots of the same saliva pool). Depending on which assay was used, however, oral stimulants increased or decreased the cortisol levels reported, with effects sizes in the small to medium range. Thus, oral stimulants should not be used with only a portion of the subjects in a study, nor should researchers assay stimulant‐treated samples from the same study using different assays. When used sparingly, oral stimulants can be employed without compromising the quality of salivary cortisol data. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 369–376, 2005.
Maternal influences on adult stress and anxiety‐like behavior in C57BL/6J and BALB/cJ mice: A cross‐fostering study
Authors: Priebe Kristianne , Brake Wayne G. , Romeo Russell D. , Sisti Helene M. , Mueller Astrid , McEwen Bruce S. , Francis Darlene D.
Published: November 2005

The quality of maternal care during early life has a dramatic impact on later stress reactivity and anxiety. Two inbred mouse strains, C57BL/6J and BALB/cJ, differ in levels of maternal care, stress reactivity, and anxiety‐like behavior in adulthood. However, the relative contribution of early environmental factors and genetic predisposition to differences in these strains is not known. Maternal care, plasma corticosterone levels, emotionality, and hippocampal and paraventricular nucleus (PVN) glucocorticoid receptor mRNA levels were measured in adult C57BL/6J and BALB/cJ mice. Litters were then cross‐fostered and anxiety‐like behavior and stress reactivity was assessed in adulthood. Significantly less maternal care and elevated stress‐induced corticosterone and emotionality was observed in BALB/cJ compared to C57BL/6J mice. Yet, no strain differences were found in hippocampal or paraventricular nucleus glucocorticoid receptor mRNA levels. Cross‐fostering did alter anxiety‐like behavior and basal corticosterone levels, which suggests that while genetic differences account for some of the variations between these two strains early rearing conditions also contribute. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 398–407, 2005.
Developmental changes in the functional brain responses of adolescents to images of high and low‐calorie foods
Authors: Killgore William D. S. , Yurgelun‐Todd Deborah A.
Published: November 2005

We examined cerebral responses to visually presented food images in children and adolescents. Eight healthy normal‐weight females (ages 9–15) underwent functional magnetic resonance imaging (fMRI) while viewing photographs of high‐ and low‐calorie foods and dining utensils. In general, food images yielded significant activation within the inferior orbitofrontal cortex, hippocampus, and fusiform gyri. High calorie food images activated the left hippocampus and subgenual cingulate, and age correlated positively with activity within the orbitofrontal cortex but negatively with activity within the anterior cingulate gyrus. Low‐calorie foods activated the fusiform gyrus and demonstrated age‐related increases in the left superior temporal gyrus and anterior cingulate. Utensils activated the fusiform gyrus and showed age‐related increases in the prefrontal cortex. Data were also compared statistically to a sample of adults exposed to the same stimulus conditions. Findings support a developmental model of adolescent maturation whereby age‐related changes in cerebral functioning develop from lower‐order sensory processing toward higher‐order processing of stimuli via prefrontal cortical systems involved in reward anticipation, self‐monitoring, and behavioral inhibition. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 377–397, 2005.
Childcare as a stabilizing influence on HPA axis functioning: A reevaluation of maternal occupational patterns and familial relations
Authors: Chryssanthopoulou C.C. , Turner‐Cobb J.M. , Lucas A. , Jessop D.
Published: November 2005

The influence of family relations, maternal occupational characteristics, and childcare1

The UK terms “childcare,” childcare centres' and “nurseries” are used throughout this paper to define group care for children prior to starting their first year of formal schooling at age 4 years and are used synonymously with the American terms “day‐care” and “preschool.” This form of group care is provided in a formal setting, outside the family home and excludes “childminding” (i.e., childcare that may be group based and offered at the home of the care provider/childminder). In the UK, this form of childcare is offered from zero to 4 years old. Children are separated according to their age into small groups usually consisting of 10–15 children. In the present study, all children were in the preschool‐aged group (3–4 years old). Where childcare of a different or more generic form is referred to, then this has been made clear in the context or stated in the text.

utilization on preschool children's cortisol production were investigated in 56 mother–child dyads. Family characteristics and maternal employment, childcare and child temperament were reported by mothers. Morning and evening levels of children's salivary cortisol were obtained. Children in highly expressive or reserved families exhibited higher cortisol levels compared to children in moderately expressive families. Elevated levels of cortisol were detected in children of mothers reporting low levels of job role quality or high levels of emotional exhaustion. Frequent childcare use was found to protect children against the physiological effects of low maternal job role quality and emotional exhaustion. Findings underscore the pervasive role of the family as set within an external support system and highlight the potential physiological impact of these interacting contexts for children. Further research is needed to fully understand current findings and to develop appropriate psycho‐physiological interventions. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 354–368, 2005.
Effects of different opportunities for social interaction on the play fighting behavior in male and female golden hamsters (Mesocricetus auratus)
Authors: Vieira Mauro Luís , Garcia Murilo Pereira , Rau Débora Driemeyer Wilbert , Prado Alessandra Bonassoli
Published: November 2005

After social isolation, animals play significantly more than nonisolated animals. However, it is not always possible to affirm that the effect of the social isolation is due to the lack of play. Experimentally, selective privation has been used, such as allowing the animals to play during periods of the day. In the present study, two experiments were carried out to verify the possible differences in the play fighting behavior of golden hamsters that were allowed to have different daily periods of social interaction (10 min, 1 hr, or 2 hr). Through the statistical analysis, it was shown that males play more than females and that periods of up to 2 hr daily for interaction are insufficient to avoid the short‐term effects of isolation. It is concluded that a period of daily social interaction greater than 2 hr is needed to offset the effects of social isolation in golden hamsters. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 345–353, 2005.
Conjugate limb coordination after experience with an interlimb yoke: Evidence for motor learning in the rat fetus
Authors: Robinson Scott R.
Published: November 2005

This study investigated the capacity of the E20 rat fetus to adaptively alter patterns of interlimb coordination in a prenatal model of motor learning. Fetal limb movement was manipulated with an interlimb yoke, consisting of a fine thread attached at the ankles, which created a physical linkage between two limbs. Exposure to the yoke resulted in a gradual increase in conjugate movements of the yoked limbs during a 30‐min training period, which persisted after removal of the yoke. Training effects were evident when the yoke was applied to two hindlimbs, two forelimbs, or a homolateral forelimb–hindlimb pair. A savings in the rate of acquisition also was observed when fetuses experienced yoke training in a second session. These data argue that the rat fetus can respond to kinesthetic feedback resulting from variation in motor performance, which suggests that experience contributes to the development of coordinated motor behavior before birth. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 328–344, 2005.
Regularities and diversity in developmental pathways: Mother–infant relationships in hamadryas baboons
Authors: Hernández‐Lloreda María Victoria , Colmenares Fernando
Published: November 2005

Change, stasis, stability, discontinuity, orderliness, and diversity are all potential characteristics of developmental systems. This study uses multilevel modeling to characterize the normative developmental pathways of the early social relationships of 23 mother–infant pairs embedded in a multilayered colony of hamadryas baboons (Papio hamadryas hamadryas). The relationships were assessed by means of 27 behavioral measures that were collected during 100–220 focal sampling sessions per infant, from birth to 380 days of age (25 two‐week age intervals). Seventy four percent of the behavioral measures exhibited an age‐related pattern. Infant age, however, was not predictive of the rate of the behaviors relating to the management of mother–infant conflicts. This study provides empirical evidence that the development of mother–infant relationships may involve periods of change and stasis, overall orderliness, and diversity as well as canalization of developmental pathways. We believe that growth curve analysis can be useful to tackle various hot issues in the study of behavioral development. © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 297–317, 2005.
Functional vulnerability of developing central nervous system to maternal thiamine deficiencies in the rat
Authors: Bâ Abdoulaye
Published: November 2005

Thiamine deficiency (B1 vitamin) was induced during three periods of rat central nervous system (CNS) ontogenesis. Females were fed a thiamine deficient diet such that developing offspring were exposed either to pre‐, peri‐, or postnatal thiamine deficiency. To control the effects of undernourishment generated by different thiamine deficiencies, every treatment group had its own pair‐fed control pup from a non drug‐treated but undernourished dam. Seven different developmental abilities (exploratory activity, emotional reaction, hind paws lifting reflex, wire grasping times, crawling and leap execution latencies, and nociception) were recorded in the offspring from the 10th to the 45th postnatal day. The vulnerability of developing brain to the specific lack of B1 vitamin increases from prenatal (28%) to perinatal (43%) and postnatal periods (57%). © 2005 Wiley Periodicals, Inc. Dev Psychobiol 47: 408–414, 2005.
Soluble adhesion molecules in young children with signs of β‐cell autoimmunity—prospective follow‐up from birth
Authors: Toivonen Anna M. , Kimpimäki Teija , Kupila Antti , Korhonen Sari , Hyöty Heikki , Virtanen Suvi M. , Ilonen Jorma , Simell Olli , Knip Mikael
Published: November 2005

Background

This study aimed at evaluating the relationship between the circulating concentrations of soluble intercellular adhesion molecule‐1 (sICAM‐1) and sL‐selectin and the appearance of β‐cell autoimmunity, and at assessing whether these molecules could assist in the identification of environmental factors implicated in the immune process damaging the pancreatic β‐cells.

Methods

Serum levels of soluble adhesion molecules were measured with enzyme‐linked immunosorbent assays over the first 2 years of life in 65 children seroconverting to positivity for autoantibodies and 65 control children, all with HLA‐conferred susceptibility to type 1 diabetes (T1D).

Results

The total integrated concentrations of soluble adhesion molecules were comparable between the two groups. The autoantibody‐positive children tended to have higher sL‐selectin concentrations during the 3‐month seroconversion (SC) period than did the control children during the corresponding period (P = 0.07), the difference being significant (P = 0.03) after excluding subjects with signs of a concurrent enterovirus infection. Autoantibody‐positive children had higher concentrations of sL‐selectin in the 3‐month period when an enterovirus infection was detectable than did the control children (P = 0.018). No significant difference could, however, be seen after excluding the children with concomitant seroconversion to autoantibody positivity.

Conclusions

Elevated concentrations of sL‐selectin are temporally associated with seroconversion to autoantibody positivity suggesting that leukocyte activation might coincide with the appearance of β‐cell autoimmunity. Early‐onset progressive β‐cell autoimmunity, on the other hand, is not reflected in overall increased concentrations of soluble adhesion molecules in the peripheral circulation during the first 2 years of life in children carrying increased HLA‐conferred disease susceptibility. Enterovirus infections (EVIs) are not independently associated with increased circulating sL‐selectin concentrations in young children with enhanced HLA‐conferred susceptibility to T1D. Copyright © 2005 John Wiley & Sons, Ltd.
Pulse pressure and mortality in hypertensive type 2 diabetic patients. A cohort study
Authors: Mannucci Edoardo , Lambertucci Lorella , Monami Matteo , Fedeli Angela , Chiasserini Veronica , Marchionni Niccolò , Masotti Giulio , Ungar Andrea
Published: November 2005

Hypothesis

Hypertension is a well‐known cardiovascular risk factor in type 2 diabetic patients. It has been suggested that pulse pressure (PP) could be an independent cardiovascular risk factor in the general population, particularly in the elderly. An association between office PP and cardiovascular mortality has been previously reported in diabetic patients, while the relationship between ambulatory measurements of PP and all‐cause mortality has not been assessed so far.

Aim

To assess the relationship between ambulatory PP and all‐cause mortality in diabetic patients with hypertension.

Methods

A cohort study was performed on a consecutive series of 435 diabetic outpatients. All patients underwent office blood pressure measurement (OBP) and 24‐h ambulatory blood pressure monitoring (ABPM). Mortality was assessed through queries at the Registry Offices of the city of residence for each patient. Mean follow‐up was 3.8 ± 1.2 years.

Results

Fifty‐eight patients (13.3%) died during the follow‐up. Mortality was significantly (p < 0.05) higher in patients in the highest quartile and lower in patients in the lowest quartile, when compared to the intermediate quartiles, both for office and ABPM‐PP. In a multivariate analysis, after adjustment for numerous variables (including current hypoglycaemic, antihypertensive statin and aspirin treatment), mortality was increased by 3.1 and 5.3% for each incremental mmHg of office PP (p < 0.05) and ABPM‐PP (p < 0.001) respectively.

Conclusions

High PP, assessed through office measurement or ABPM, was associated with increased mortality in hypertensive type 2 diabetic patients. In our sample, PP assessed with ABPM is a better predictor of mortality than office PP. Copyright © 2005 John Wiley & Sons, Ltd.
Migratory routes and fates of cells transcribing the Wnt‐1 gene in the murine hindbrain
Authors: Nichols David H. , Bruce Laura L.
Published: November 2005

To investigate the origins, migrations, and fates of Wnt‐1–expressing cells in the murine hindbrain, mice carrying a Wnt‐1 enhancer/lacZ transgene were observed from embryonic day (E) 8 through postnatal day 18. The transgene‐stained ventricular layer waxed and waned prior to and following migrations from it. Stained cells migrated first external to the hindbrain as neural crest and then within it to form typical populations of the rhombic lip, as well as others not recognized as lip derivatives. Migrations originated in a temporally defined sequence, many from discrete rhombomeres. All moved first radially, then rostrally and/or ventrally, ipsi‐, or contralaterally, in the mantle or marginal layers. These movements ultimately formed elements of several nuclei, aligned in four longitudinal bands: dorsal (including the gracile, cuneate, cochlear, and vestibular nuclei, plus cerebellar granular cells), dorsal intermediate (including trigeminal sensory, parvicellular reticular, and deep cerebellar nuclei), ventral intermediate (including lateral and intermediate reticular nuclei), and ventral (including the raphe obscurus and pontine nuclei). Transgene staining often persisted long enough to identify stained cells in their definitive, adult nuclei. However, staining was transient. The strength of the staining, however, was in its ability to reveal origins and migrations in both whole‐mounts and sections, in single cell detail. The present results will permit analyses of the effects of genetic manipulations on Wnt‐1 lineage cells. Developmental Dynamics 235:285–300, 2006. © 2005 Wiley‐Liss, Inc.
Imbalance in liver homeostasis leading to hyperplasia by overexpressing either one of the Bcl‐2‐related genes, zfBLP1 and zfMcl‐1a
Authors: Her Guor Mour , Cheng Chih‐Hung , Hong Jiann‐Ruey , Sundaram Gnanapackiam Sheela , Wu Jen‐Leih
Published: November 2005

Apoptosis is an essential part of normal embryonic development in vertebrates, and it is involved in sculpturing organs and controlling cell populations. In previous studies, we identified two novel proteins, zfBLP1 and zfMcl‐1a, which are similar to those of the Bcl‐2 family as a group of evolutionarily conserved proteins that regulate cellular anti‐apoptosis. To evaluate the effect of dysregulated hepatocyte apoptosis during zebrafish hepatogenesis, we demonstrate the transgenic overexpression of either zfBLP1 or zfMcl‐1a in zebrafish larval liver. Results showed that 18%–43% of larvae overexpressed zfBLP1 and that 16%–37% of larvae overexpressed zfMc1‐1a in the liver leading to liver hyperplasia in 5‐day postfertilization (dpf) zebrafish larvae. Histologically, zebrafish larvae exhibiting liver hyperplasia displayed a normal type of hepatocyte and the same cell numbers in their two liver buds compared with only one liver bud of wild‐type larvae. Of interest, the expression of cyclin genes (A2, B, D1, and E), hepatocyte nuclear factor genes (HNF‐1α, β, ‐3β, and 4α), and oncogenic markers (P53, c‐myc, β‐catenin, N‐ras, and gankyrin) were up‐regulated, while the expression of C/EBP‐α was down‐regulated in a zfMcl‐1a–mediated anti‐apoptotic process of the liver. Increased cell death and proliferation was found in both hepatic cells of zebrafish larvae overexpressing either zfBLP1 or zfMcl‐1a. However, those zebrafish larvae with liver hyperplasia only lived approximately 10 days. (This finding may have been due to liver abnormalities that led to failure of liver function.) In conclusion, transgenic overexpression of zfBLP1 or zfMcl‐1a in zebrafish larvae interrupts regulation of the homeostatic balance between cell proliferation and programmed cell death during hepatogenesis and leads to liver hyperplasia. Developmental Dynamics 235:515–523, 2006. © 2005 Wiley‐Liss, Inc.
Genomic profiling of Mixer and Sox17β targets during Xenopus endoderm development
Authors: Dickinson Kari , Leonard Jeff , Baker Julie C.
Published: November 2005

The transcription factors Mixer and Sox17β have well‐characterized roles in endoderm specification during Xenopus embryogenesis. In order to more thoroughly understand the mechanisms by which these endodermal regulators act, we expressed Mixer and Sox17β in naïve ectodermal tissue and, using oligonucleotide‐based microarrays, compared their genomic transcriptional profile to that of unaffected tissue. Using this approach, we identified 71 transcripts that are upregulated by Mixer or Sox17β, 63 of which have previously uncharacterized roles in endoderm development. Furthermore, an in situ hybridization screen using antisense probes for several of these clones identified six targets of Mixer and/or Sox17β that are expressed in the endoderm during gastrula stages, providing new and regional markers of the endoderm. Our results contribute further insight into the functions of Mixer and Sox17β and bring us closer to understanding at the molecular level the pathways that regulate endoderm development. Developmental Dynamics 235:368–381, 2006. © 2005 Wiley‐Liss, Inc.