bluuebunny/crossref_metadata_2025 huggingface dataset:
Confined swirling jet impingement on a flat plate at moderate Reynolds numbers
Authors: Herrada M. A. , Del Pino C. , Ortega-Casanova J.
Published: January 2009

The behavior of a swirling jet issuing from a pipe and impinging on a flat smooth wall is analyzed numerically by means of axisymmetric simulations. The axial velocity profile at the pipe outlet is assumed flat while the azimuthal velocity profile is a Burger’s vortex characterized by two non-dimensional parameters; a swirl number S and a vortex core length δ. We concentrate on the effects of these two parameters on the mechanical characteristics of the flow at moderate Reynolds numbers. Our results for S=0 are in agreement with Phares et al. [J. Fluid Mech. 418, 351 (2000)], who provide a theoretical determination of the wall shear stress under nonswirling impinging jets at high Reynolds numbers. In addition, we show that the swirl number has an important effect on the jet impact process. For a fixed nozzle-to-plate separation, we found that depending on the value of δ and the Reynolds number Re, there is a critical swirl number, S=S∗(δ,Re), above which recirculating vortex breakdown bubbles are observed in the near axis region. For S>S∗, the presence of these bubbles enhances the transition from a steady to a periodic regime. For S<S∗, the flow remains steady and the results show that the introduction of swirl reduces the maximum pressure and radial skin-friction coefficients over the wall.
Thermal conductivity of silicon nanowire by nonequilibrium molecular dynamics simulations
Authors: Wang Shuai-chuang , Liang Xin-gang , Xu Xiang-hua , Ohara Taku
Published: January 2009

The thermal conductivity of silicon nanowires was predicted using the nonequilibrium molecular dynamics method using the Stillinger–Weber potential model and the Nose–Hoover thermostat. The dependence of the thermal conductivity on the wire length, cross-sectional area, and temperature was investigated. The surface along the longitudinal direction was set as a free boundary with potential boundaries in the other directions. The cross-sectional areas of the nanowires ranged from about 5 to 19 nm2 with lengths ranging from 6 to 54 nm. The thermal conductivity dependence on temperature agrees well with the experimental results. The reciprocal of the thermal conductivity was found to be linearly related to the nanowire length. These results quantitatively show that decreasing the cross-sectional area reduces the phonon mean free path in nanowires.
Free electron behavior in InN: On the role of dislocations and surface electron accumulation
Authors: Darakchieva V. , Hofmann T. , Schubert M. , Sernelius B. E. , Monemar B. , Persson P. O. Å. , Giuliani F. , Alves E. , Lu H. , Schaff W. J.
Published: January 2009

The free electron behavior in InN is studied on the basis of decoupled bulk and surface accumulation electron densities in InN films measured by contactless optical Hall effect. It is shown that the variation in the bulk electron density with film thickness does not follow the models of free electrons generated by dislocation-associated nitrogen vacancies. This finding, further supported by transmission electron microscopy results, indicates the existence of a different thickness-dependent doping mechanism. Furthermore, we observe a noticeable dependence of the surface electron density on the bulk density, which can be exploited for tuning the surface charge in future InN based devices.
Ultrafast all-optical modulation in GaAs photonic crystal cavities
Authors: Husko Chad , De Rossi Alfredo , Combrié Sylvain , Tran Quynh Vy , Raineri Fabrice , Wong Chee Wei
Published: January 2009

We demonstrate all-optical modulation based on ultrafast optical carrier injection in a GaAs photonic crystal cavity using a degenerate pump-probe technique. The observations agree well with a coupled-mode model incorporating all relevant nonlinearities. The low switching energy (∼120 fJ), small energy absorption (∼10 fJ), fast on-off response (∼15 ps), limited only by carrier lifetime, and a minimum 10 dB modulation depth suggest practical all-optical switching applications at high repetition rates.
Size-dependent photoelastic effect in ZnO nanorods
Authors: Shih H. Y. , Chen T. T. , Chen Y. C. , Lin T. H. , Chang L. W. , Chen Y. F.
Published: January 2009

Manipulation of internal strain by an external light beam called photoelastic effect has been firmly established in ZnO nanorods. The underlying mechanism of this interesting phenomenon arises from the combination of the screening of internal electric field and converse piezoelectric effect. We demonstrate that the photoelastic effect is more pronounced in thinner nanorods due to a larger surface to volume ratio. In addition to giving a good evidence for the existence of photoelastic effect in semiconductor nanorods, our finding also provides an excellent possibility for the development of nanoscale optical modulators.
The energetics of dislocations accelerating and decelerating through the shear-wave speed barrier
Authors: Markenscoff Xanthippi , Huang Surong
Published: January 2009

The question of whether a dislocation can accelerate through the shear-wave speed “barrier” is addressed by analyzing the transient motion at the instant when the velocity equals the shear-wave speed in the presence of acceleration. The stresses carried by the forming Mach wave fronts depend on the acceleration at this instant, and the energy required to push the dislocation through the shear-wave speed barrier is determined by means of the “contour-independent” dynamic J integral, which defines the self-force on a moving defect, and is obtained as a function of the acceleration as it crosses the barrier. For decelerating motion through the shear-wave speed barrier this energy is released as dissipation.
Aspheric silicon lenses for terahertz photoconductive antennas
Authors: Formanek Florian , Brun Marc-Aurèle , Umetsu Tomoyuki , Omori Shinji , Yasuda Akio
Published: January 2009

We report on the design and characterization of aspheric focusing silicon lenses for terahertz photoconductive antennas. The lenses are engineered using ray-tracing software and characterized using an optical fiber terahertz time-domain spectroscopy system. We find that using aspheric lenses improves terahertz radiation coupling from the emitter and enables improved collection by the detector. The signal-to-noise ratio and the cutoff frequency of measured terahertz spectra are improved. Minimized aberrations also reduce the focal spot size. Simulations based on Fresnel–Kirchhoff diffraction theory, taking into account the radiation pattern of the emitter and aberrations of the lenses, show good agreement with our measurements.
Lead salt microdisk lasers operating in continuous wave mode at 5.3 μm wavelength
Authors: Eibelhuber M. , Schwarzl T. , Springholz G. , Heiss W.
Published: January 2009

Lead salt microdisk lasers with midinfrared emission around 5.3 μm are demonstrated. The laser structures were grown by molecular beam epitaxy on BaF2 substrates and consist of Pb0.95Sr0.05Se spacer layers and a ten-period PbSe/Pb0.95Sr0.05Se multi-quantum-well active region. Under optical excitation, single mode continuous-wave lasing is obtained up to temperatures of 135 K from microdisks with a diameter of 45 μm. With increasing temperature the laser emission continuously switches to resonator modes at shorter wavelengths. The lasers exhibit a threshold pump power of only 1.47 mW (75 W/cm2) at 115 K.
Ellipsoidal InAs quantum dots observed by cross-sectional scanning tunneling microscopy
Authors: Blokland J. H. , Bozkurt M. , Ulloa J. M. , Reuter D. , Wieck A. D. , Koenraad P. M. , Christianen P. C. M. , Maan J. C.
Published: January 2009

We report a detailed analysis of the shape, size, and composition of self-assembled InAs quantum dots based on cross-sectional scanning tunneling microscopy (X-STM) experiments. X-STM measurements on 13 individual quantum dots reveal an ellipsoidal dot shape with an average height of 8 nm and a diameter of 26 nm. Analysis of the outward relaxation and lattice constant profiles shows that the dots consist of an InGaAs alloy with a profound gradient in the indium concentration in both horizontal and vertical directions. These results are important to obtain a deeper understanding of the relationship between the structural and electronic properties of semiconductor quantum dots.
Self-organized patterns by optical nonlinearity in 4-(4-pentenyloxy)benzonitrile
Authors: Trejo-Durán Mónica , Alvarado-Méndez Edgar , Castaño Víctor M.
Published: January 2009

Optical characterization of the organic compound 4-(4-pentenyloxy)benzonitrile under two different conditions was carried out. The experiments show deformation of the scattered light spots upon heating as well as evidence of a thermally self-induced nonlinearity. In consequence, self-diffraction pattern, self-bending, and filamentation of the impinging beam appear as a function of the laser power, creating self-organized patterning during the filamentation due to modulation instabilities.
Atomic-scale in situ observation of lattice dislocations passing through twin boundaries
Authors: Wang Y. B. , Sui M. L.
Published: January 2009

In situ transmission electron microscopy tensile experiments were carried out to investigate lattice dislocation and twin boundary (TB) interaction in Cu with nanoscale growth twins. Results show that extended dislocations form inside thick twin lamellas and slip toward TBs. The extended dislocations shrink, combine, and redissociate when they pass through TBs, leaving behind detwinning partial dislocations at the TBs. The mechanism of the observed dislocation/TB interactions and the effect of the mechanism on mechanical properties are discussed.
Structural and thermoelectric properties of Bi2Sr2Co2Oy thin films on LaAlO3 (100) and fused silica substrates
Authors: Wang Shufang , Venimadhav A. , Guo Shengming , Chen Ke , Li Qi , Soukiassian A. , Schlom Darrell G. , Katz Michael B. , Pan X. Q. , Wong-Ng Winnie , Vaudin Mark D. , Xi X. X.
Published: January 2009

We have grown Bi2Sr2Co2Oy thin films on LaAlO3 (100) and fused silica substrates by pulsed laser deposition. The films on LaAlO3 are c-axis oriented and partially in-plane aligned with multiple domains, while the films on fused silica are preferred c-axis oriented without in-plane alignment. The Seebeck coefficient and resistivity of films on both substrates are comparable to those of single crystals. An oxide p-n heterojunction was formed by depositing Bi2Sr2Co2Oy film on Nb-doped SrTiO3 single crystal, which showed a rectifying behavior. These thin films and heterostructures may be used for future thermoelectric applications.
Optical bandgap widening of p-type Cu2O films by nitrogen doping
Authors: Nakano Yoshitaka , Saeki Shu , Morikawa Takeshi
Published: January 2009

We have investigated the effect of N doping into Cu2O films deposited by reactive magnetron sputtering. With increasing N-doping concentration up to 3%, the optical bandgap energy is enlarged from ∼2.1 to ∼2.5 eV with retaining p-type conductivity as determined by optical absorption and Hall effect measurements. Additionally, photoelectron spectroscopy in air measurements shows an increase in the valence and conduction band shifts with N doping. These experimental results demonstrate possible optical bandgap widening of p-type N-doped Cu2O films, which is a phenomenon that is probably associated with significant structural changes induced by N doping, as suggested from x-ray diffraction measurements.
A Bestiary
Authors: Stone Yvonne
Published: January 2009

being a Book of Beasts, a naturalist's guide to particle physics of the twentieth century
Activated Wnt/ß-catenin signaling in melanoma is associated with decreased proliferation in patient tumors and a murine melanoma model
Authors: Chien Andy J. , Moore Erin C. , Lonsdorf Anke S. , Kulikauskas Rima M. , Rothberg Bonnie Gould , Berger Aaron J. , Major Michael B. , Hwang Sam T. , Rimm David L. , Moon Randall T.
Published: January 2009

This study demonstrates that in malignant melanoma, elevated levels of nuclear ß-catenin in both primary tumors and metastases correlate with reduced expression of a marker of proliferation and with improved survival, in contrast to colorectal cancer. The reduction in proliferation observed in vivo is recapitulated in B16 murine melanoma cells and in human melanoma cell lines cultured in vitro with either WNT3A or small-molecule activators of ß-catenin signaling. Consistent with these results, B16 melanoma cells expressing
WNT3A
also exhibit decreased tumor size and decreased metastasis when implanted into mice. Genome-wide transcriptional profiling reveals that WNT3A up-regulates genes implicated in melanocyte differentiation, several of which are down-regulated with melanoma progression. These findings suggest that WNT3A can mediate transcriptional changes in melanoma cells in a manner reminiscent of the known role of Wnt/ß-catenin signaling in normal melanocyte development, thereby altering melanoma cell fate to one that may be less proliferative and potentially less aggressive. Our results may explain the observed loss of nuclear ß-catenin with melanoma progression in human tumors, which could reflect a dysregulation of cellular differentiation through a loss of homeostatic Wnt/ß-catenin signaling.
Human embryonic stem cell phosphoproteome revealed by electron transfer dissociation tandem mass spectrometry
Authors: Swaney Danielle L. , Wenger Craig D. , Thomson James A. , Coon Joshua J.
Published: January 2009

Protein phosphorylation is central to the understanding of cellular signaling, and cellular signaling is suggested to play a major role in the regulation of human embryonic stem (ES) cell pluripotency. Here, we describe the use of conventional tandem mass spectrometry-based sequencing technology—collision-activated dissociation (CAD)—and the more recently developed method electron transfer dissociation (ETD) to characterize the human ES cell phosphoproteome. In total, these experiments resulted in the identification of 11,995 unique phosphopeptides, corresponding to 10,844 nonredundant phosphorylation sites, at a 1% false discovery rate (FDR). Among these phosphorylation sites are 5 localized to 2 pluripotency critical transcription factors—OCT4 and SOX2. From these experiments, we conclude that ETD identifies a larger number of unique phosphopeptides than CAD (8,087 to 3,868), more frequently localizes the phosphorylation site to a specific residue (49.8% compared with 29.6%), and sequences whole classes of phosphopeptides previously unobserved.
Bias in the Classroom: Types, Frequencies, and Responses
Authors: Boysen Guy A. , Vogel David L.
Published: January 2009

Incidents of bias still occur in college classrooms, but no research has specifically explored this topic. To address this gap in the literature, professors (N = 333) completed anonymous surveys assessing types of bias they perceived in their classroom, their responses to the bias, and the perceived success of their responses. Results indicated that 38% of professors perceived an incident of bias in the classroom in the last year, and that they perceived overt (i.e., explicit) and subtle (i.e., implicit) bias with similar frequency. Professors believed their responses to bias were successful on average, but many could not assess success. Bias, in all its forms, still exists in college classrooms, and more discussion and research about its management is necessary.
Mastery Quizzing as a Signaling Device to Cue Attention to Lecture Material
Authors: Nevid Jeffrey S. , Mahon Katie
Published: January 2009

A mastery quiz is a miniquiz given at the start and end of a lecture period used to signal key lecture concepts. It also provides an incentive for focused attention and regular and punctual attendance. Students earn points toward their final grades for submitting correct responses at either or both testings. Introductory psychology students showed significant improvement in knowledge of mastery quiz content as assessed by pre–post lecture comparisons. Credits earned on mastery quizzes also predicted performance on course examination questions measuring signaled concepts and other concepts from lectures on days that mastery quizzes were administered.
Platelet‐Mediated Enhancement of Leukocyte Adhesion
Authors: HUNDELSHAUSEN PHILIPP VON , KOENEN RORY R. , WEBER CHRISTIAN
Published: January 2009

Recruitment of inflammatory cells in the perivascular tissue is a necessity for many physiological processes. While the inflammatory influx of cells to combat infection near the entrance site of infective agents is protective, it also drives the development of diseases, such as atherosclerosis. We know from the multistep model that cellular recruitment consists of overlapping sequences initiated by capturing and rolling of the cell, followed by adhesion, which is of paramount importance and indispensable for the subsequent transendothelial migration. The spectrum of molecules and cells involved in these processes is vast. Platelets have evolved in several ways as amplifiers of leukocyte adhesion, since beyond their central role in primary hemostasis, their repertoire of adhesion molecules and soluble mediators renders them important interplayers between endothelial cells and blood‐borne immune cells.
Parent and self‐ratings of executive function in adolescents with specific language impairment
Authors: Hughes Deanna M. , Turkstra Lyn S. , Wulfeck Beverly B.
Published: January 2009

Background: There is accumulating evidence that adolescents with specific language impairment (SLI) have impairments in domains beyond formal language that may affect academic and social outcomes. The findings of previous studies as well as parent reports of behavioural concerns suggest that they lag behind peers in functions such as self‐regulation of verbal behaviour and strategic language use suggesting that executive function may be a potential domain worthy of study in adolescents with SLI. The evaluation of executive functions in daily living could provide critical information for intervention for adolescents with SLI, and also inform studies of the relationship between language and executive functioning in a developing system.

Aims: To compare ratings of executive function in adolescents with specific language impairment to those of their parents and typically developing peers.

Methods & Procedures: This study examined parent and self‐ratings of executive function in adolescents with SLI and typically developing peers. Twenty‐one adolescents with SLI and 21 age‐ and gender‐matched peers (age range = 11–18 years) rated their executive functions in daily living using the Behavior Rating Inventory of Executive Function — Self‐Report Form (BRIEF‐SR), and their parents provided companion ratings.

Outcomes & Results: Adolescents in both groups rated themselves more positively than did their parents, and the presence of language impairment was associated with more negative ratings by both parents and adolescents. Fifty‐seven per cent of the parents of adolescents with SLI rated their child's executive function abilities as being in the clinically impaired range, compared with 10% in the typically developing group.

Conclusions & Implications: The results of this study suggest that many adolescents with SLI have perceived impairments in executive functions that affect their performance in daily living. What remains to be determined is whether language and executive function impairments are co‐morbid conditions or causally linked. Few assessment tools address the unique characteristics of adolescent clinical populations, including those with SLI. These findings suggest that self‐ and parent ratings of executive function may offer useful information for treatment planning. A greater understanding of the relation of executive functions to language has important implications for the timing and content of therapeutic intervention.
Comprehension of metaphor and metonymy in children with Williams syndrome
Authors: Annaz Dagmara , Van Herwegen Jo , Thomas Michael , Fishman Roza , Karmiloff‐Smith Annette , Rundblad Gabriella
Published: January 2009

Background: Figurative language, such as metaphor and metonymy, is very common in daily language use. Its underlying cognitive processes are sometimes viewed as lying at the interface of language and thought. Williams syndrome, which is a rare genetic developmental disorder, provides an opportunity to study this interface because individuals with this disorder have relative strengths in vocabulary and syntax against a background of low general cognitive ability. Few studies have investigated metaphor comprehension in Williams syndrome and none has investigated metonymy.

Aims: This is the first study to investigate metaphor and metonymy comprehension in Williams syndrome and to compare their performance with a group of typically developing children.

Methods & Procedures: Ten children with Williams syndrome were compared with eleven typically developing children in a novel metaphor–metonymy comprehension task. Cross‐sectional trajectory analyses were used to compare the development of metaphor and metonymy using a child‐friendly story picture task. Trajectories were constructed linking task performance either to chronological age or to measures of mental age (receptive vocabulary, visuospatial construction).

Outcomes & Results: The performance of children with Williams syndrome was significantly poorer than the typically developing group. The comprehension of metonyms was in line with receptive vocabulary, but comprehension of metaphors fell below this level.

Conclusions & Implications: Metonyms may be part of vocabulary and treated as synonyms in Williams syndrome, while metaphor engages additional cognitive mechanisms outside language that develop atypically in this disorder. Despite earlier reports that emphasize good language skills, the Williams syndrome language system shows anomalies compared with typical development.
Acquired dysarthria in conversation: Identifying sources of understandability problems
Authors: Bloch Steven , Wilkinson Ray
Published: January 2009

Background: Acquired progressive dysarthria is traditionally assessed, rated, and researched using measures of speech perception and intelligibility. The focus is commonly on the individual with dysarthria and how speech deviates from a normative range. A complementary approach is to consider the features and consequences of dysarthric speech as it is produced as a turn‐at‐talk in everyday interaction and in particular the ways in which this talk may be identified by its recipient as problematic to understand.

Aims: To investigate how dysarthric turns‐at‐talk in everyday conversation may be problematic to understand. Further, to describe how recipients of dysarthric talk identify the source of problematic understandings to the dysarthric speaker.

Methods & Procedures: Video data of natural conversation from two dyads were selected for this paper. The dyads were video‐recorded at home, at 3‐monthly intervals, over a maximum period of 18 months. Using the methods of conversation analysis a collection of sequences was identified and transcribed. The sequences were analysed with reference to how the recipients of dysarthric talk, through the use of other‐initiations of repair, identified some element of that talk as problematic.

Outcomes & Results: This work shows how a recipient of a dysarthric talk turn in everyday conversation goes about displaying the problematicity of that turn to its speaker. Whilst displaying that a problem exists with a prior turn, the recipient may have difficulty in knowing what that problem actually is.

Conclusions & Implications: It is proposed that clinicians and researchers should consider the effects of dysarthric speech in interaction. Specifically, the nature of dysarthric troubles and the practices used to signal understanding problems as they occur in everyday interaction should be fully explored. This consideration may have relevance for clinical assessment and intervention.
Rational numbers: Componential versus holistic representation of fractions in a magnitude comparison task
Authors: Meert Gaëlle , Grégoire Jacques , Noël Marie-Pascale
Published: January 2009

This study investigated whether the mental representation of the fraction magnitude was componential and/or holistic in a numerical comparison task performed by adults. In Experiment 1, the comparison of fractions with common numerators (x/a_x/b) and of fractions with common denominators (a/x_b/x) primed the comparison of natural numbers. In Experiment 2, fillers (i.e., fractions without common components) were added to reduce the regularity of the stimuli. In both experiments, distance effects indicated that participants compared the numerators for a/x_b/x fractions, but that the magnitudes of the whole fractions were accessed and compared for x/a_x/b fractions. The priming effect of x/a_x/b fractions on natural numbers suggested that the interference of the denominator magnitude was controlled during the comparison of these fractions. These results suggested a hybrid representation of their magnitude (i.e., componential and holistic). In conclusion, the magnitude of the whole fraction can be accessed, probably by estimating the ratio between the magnitude of the denominator and the magnitude of the numerator. However, adults might prefer to rely on the magnitudes of the components and compare the magnitudes of the whole fractions only when the use of a componential strategy is made difficult.
Short Article: Attentional Orientation Induced by Temporarily Established Self-Referential Cues
Authors: Sui Jie , Liu Chang Hong , Wang Lingyun , Han Shihui
Published: January 2009

Self-referential stimuli such as self-face surpass other-referential stimuli in capture of attention, which has been attributed to attractive perceptual features of self-referential stimuli. We investigated whether temporarily established self-referential stimuli are different from other-referential cues in guiding voluntary visual attention. Temporarily established self-referential or friend-referential shapes served as central cues in Posner's endogenous cueing task. We found that, relative to friend-referential cues, self-referential cues induced smaller cueing effect (i.e., the difference in reaction times to targets at cued and uncued locations) when the interstimulus interval was short but larger cueing effect when the interstimulus interval was long. Our findings suggest that temporarily established self-referential cues are more efficient to capture reflexive attention at the early stage of perceptual processing and to shift voluntary attention at the later stage of perceptual processing.
Short article: Why mix-ups don't happen in the nursery: Evidence for an experience-based interpretation of the other-age effect
Authors: Cassia Viola Macchi , Picozzi Marta , Kuefner Dana , Casati Monica
Published: January 2009

Adults’ face recognition abilities vary across face types, as evidenced by the other-race and other-species effects. Recent evidence shows that face age is another dimension affecting adults’ performance in face recognition tasks, giving rise to an other-age effect (OAE). By comparing recognition performance for adult and newborn faces in a group of maternity-ward nurses and a control group of novice participants, the current study provides evidence for an experience-based interpretation of the OAE. Novice participants were better at recognizing adult than newborn faces and showed an inversion effect for adult faces. Nurses manifested an inversion cost of equal magnitude for both adult and newborn faces and a smaller OAE in comparison to the novices. The results indicate that experience acquired exclusively in adulthood is capable of modulating the OAE and suggest that the visual processes involved in face recognition are still plastic in adulthood, granted that extensive experience with multiple faces is acquired.
Role of Tim50 in the Transfer of Precursor Proteins from the Outer to the Inner Membrane of Mitochondria
Authors: Mokranjac Dejana , Sichting Martin , Popov-Čeleketić Dušan , Mapa Koyeli , Gevorkyan-Airapetov Lada , Zohary Keren , Hell Kai , Azem Abdussalam , Neupert Walter
Published: January 2009

Transport of essentially all matrix and a number of inner membrane proteins is governed, entirely or in part, by N-terminal presequences and requires a coordinated action of the translocases of outer and inner mitochondrial membranes (TOM and TIM23 complexes). Here, we have analyzed Tim50, a subunit of the TIM23 complex that is implicated in transfer of precursors from TOM to TIM23. Tim50 is recruited to the TIM23 complex via Tim23 in an interaction that is essentially independent of the rest of the translocase. We find Tim50 in close proximity to the intermembrane space side of the TOM complex where it recognizes both types of TIM23 substrates, those that are to be transported into the matrix and those destined to the inner membrane, suggesting that Tim50 recognizes presequences. This function of Tim50 depends on its association with TIM23. We conclude that the efficient transfer of precursors between TOM and TIM23 complexes requires the concerted action of Tim50 with Tim23.
Reengineering Ribosome Export
Authors: Lo Kai-Yin , Johnson Arlen W.
Published: January 2009

Large cargoes require multiple receptors for efficient transport through the nuclear pore complex. The 60S ribosomal subunit is one of the bulkiest transport cargoes, and in yeast three different receptors, Crm1, Mex67/Mtr2, and Arx1, collaborate in its export. However, only Crm1, recruited by the adapter Nmd3, appears to be conserved for 60S export in higher eukaryotes. We asked if export of the large subunit requires specific receptors. We made protein fusions between mutant Nmd3 and various export receptors. Surprisingly, fusions of Mex67, the tRNA exportin Los1, Mtr2, Cse1, or Msn5 to Nmd3, lacking its Crm1-dependent nuclear export signal (NES), all functioned in export. Furthermore, these chimeric proteins supported 60S export even in the presence of the Crm1 inhibitor leptomycin B, indicating that export was now independent of Crm1. These results suggest that there is not a requirement for a specific export receptor for the large subunit, as recruitment of any receptor will suffice. Finally we show that the addition of an NES directly to the 60S ribosomal subunit protein Rpl3 promotes export. These results imply remarkable flexibility in the export pathway for the 60S subunit and help explain how different export receptors could have evolved in different eukaryotic lineages.
Fecal Calprotectin and Lactoferrin as Noninvasive Markers of Pediatric Inflammatory Bowel Disease
Authors: Joishy Manohara , Davies Ieuan , Ahmed Mansoor , Wassel Julie , Davies Karen , Sayers Adrian , Jenkins Huw
Published: January 2009

Objective:

To evaluate whether fecal calprotectin (FC) and fecal lactoferrin (FL) can be used as noninvasive markers in children and young people (4–17 years) with active inflammatory bowel disease (IBD).

Patients and Methods:

Stool samples were collected from 3 groups of children: those with active IBD, control individuals with other gastrointestinal (GI) diseases (GI control) and control individuals with no GI disease (non‐GI control). The number of patients for the FC assay was as follows: IBD = 26, GI control = 30, non‐GI control = 25. The number of patients for the FL assay was as follows: IBD = 24, GI control = 26, non‐GI = 24. FC and FL were measured by use of enzyme‐linked immunoassays.

Results:

The median concentrations of FC and FL in isolation, and their interaction, were significantly higher in the IBD group than in the GI and non‐GI control groups (P < 0.001). Although the area under the curve, sensitivity, and specificity for FC, FL, and FC × FL interaction were significantly better than chance, FL consistently had the lowest area under the curve, and FC × FL consistently had the highest area under the curve.

Conclusions:

FC and FL are both significantly elevated in children with IBD, and the interaction of these 2 biomarkers may produce a better initial diagnostic test compared with their use in isolation.
Use of Complementary Medicine in Pediatric Patients With Inflammatory Bowel Disease: Results From a Multicenter Survey
Authors: Wong Anthony P , Clark Ann L , Garnett Elizabeth A , Acree Michael , Cohen Stanley A , Ferry George D , Heyman Melvin B
Published: January 2009

Objectives:

We examined the use of complementary and alternative medicine (CAM) at 3 US pediatric medical centers, comparing a group of children with inflammatory bowel disease (IBD) with children presenting with chronic constipation.

Materials and Methods:

Surveys were administered by postal mail and at pediatric IBD centers in San Francisco, Houston, and Atlanta from 2001 to 2003. A comparison group consisting of pediatric patients with chronic constipation also was surveyed. Data were analyzed by t tests and by exact tests of contingency tables.

Results:

In all, 236 surveys were collected from the IBD group; 126 surveys were collected from the chronic constipation comparison group. CAM therapies were used by 50% in the IBD group and 23% in the chronic constipation group. The overall regional breakdown of CAM use in IBD revealed no differences, although the types of CAM therapy used varied by site. The most commonly used CAM therapies in the IBD group were spiritual interventions (25%) and nutritional supplements (25%). Positive predictors for CAM use in IBD include the patient's self‐reported overall health, an increase in the number of side effects associated with allopathic medications, white ethnicity, and parental education beyond high school.

Conclusions:

This is the first US study to characterize CAM use in pediatric patients with IBD with another chronic gastrointestinal disorder. CAM use was twice as common with the IBD group compared with the chronic constipation group. Regional variations exist with the types of CAM therapy used. Practitioners should know that half of their pediatric patients with IBD may be using CAM in conjunction with or as an alternative to other treatments and that certain predictors can help identify those using CAM therapies.
“pH‐Only” Acid Reflux Events in Infants During Later Phases of the Feeding Cycle Are Less Acidic and Cleared More Efficiently Than Classic 2‐Phase Acid Reflux Events
Authors: Woodley Frederick W , Mousa Hayat
Published: January 2009

Background:

Gastroesophageal acid exposure in infants is a function of 4 acid gastroesophageal reflux (AGER) types: classic 2‐phase, single‐phase, and pH‐only events (POEs), as well as rereflux episodes. In symptomatic infants, classic 2‐phase events and POEs make up the majority of total AGER events and AGER events lasting 5 minutes or longer, and are responsible for the majority of total gastroesophageal acid exposure. Also, in symptomatic infants, chemical clearance efficiency of classic 2‐phase events has been shown to be influenced by feeding. Pathogenicity of AGER involves variables that include frequency, duration, and pH of AGER events. The purpose of this investigation was to compare classic 2‐phase episodes and POEs on the basis of these variables during discrete periods related to feeding.

Patients and Methods:

Impedance/pH tracings from 12 symptomatic infants (median age 20 weeks) were examined. Mean frequencies, durations, and nadir pH values were calculated during feeding, the first hour postprandial (1stPP), the second hour postprandial (2ndPP), and fasting.

Results:

Compared with classic 2‐phase events, POEs were cleared significantly more efficiently during 1stPP (3‐fold, P = 0.02), 2ndPP (3‐fold, P = 0.0001), and fasting (4.5‐fold, P < 0.0001), and were less acidic during 2ndPP (1.9 ± 0.15 vs 2.6 ± 0.07, P = 0.0005) and fasting (1.5 ± 0.12 vs 2.9 ± 0.07, P < 0.0001). Whereas clearance of classic 2‐phase events became increasingly less efficient, clearance of POEs did not fluctuate significantly during the course of the feeding cycle.

Conclusions:

The lower acidity and more rapid clearance during 2ndPP and fasting suggest that POEs are likely to have a different clinical impact (compared with classic 2‐phase AGER events) during later phases of the feeding cycle.
Is Endoscopic Retrograde Cholangiopancreatography Valuable and Safe in Children of All Ages?
Authors: Vegting IL , Tabbers MM , Taminiau JAJM , Aronson DC , Benninga MA , Rauws EAJ
Published: January 2009

Objective:

To evaluate indications, findings, therapies, safety, and technical success of endoscopic retrograde cholangiopancreatography (ERCP) in children of the Emma Children's Hospital Academic Medical Centre in Amsterdam, the Netherlands.

Design:

Descriptive. Retrospective analysis by medical records.

Patients and Methods:

Information was obtained by chart review of patients between 0 and 18 years who underwent ERCP from 1995 to 2005 in our center. The following data were analyzed: indications, findings, therapies, safety, and technical success. Success was defined as obtaining accurate diagnostic information or succeeding in endoscopic therapy.

Results:

Sixty‐one children (age 3 days to 16.9 years, mean age 7.0 years) underwent a total of 99 ERCPs. Of those patients, 51% (31/61) were younger than 1 year, 84% had biliary indications, and 16% had pancreatic indications for the performance of ERCP. The complication rate was 4% (4/99) and included substantial pancreatitis and mild irritated pancreas. No complications occurred in children younger than 1 year.

Conclusions:

ERCP is a safe and valuable procedure for children of all ages with suspicion of pancreaticobiliary diseases. Indications for ERCP are different for children and adults. A laparotomy could be prevented in 12% of children with suspicion of biliary atresia. Further research is required to determine the role of MRCP versus ERCP.
Galacto‐oligosaccharides Are Bifidogenic and Safe at Weaning: A Double‐blind Randomized Multicenter Study
Authors: Fanaro Silvia , Marten Berit , Bagna Rossana , Vigi Vittorio , Fabris Claudio , Peña‐Quintana Luis , Argüelles Federico , Scholz‐Ahrens Katharina E , Sawatzki Günther , Zelenka Richard , Schrezenmeir Jürgen , de Vrese Michael , Bertino Enrico
Published: January 2009

Objectives:

The primary objective of this study was to determine the bifidogenic effect of galacto‐oligosaccharides (GOS) in a follow‐on formula and the effects on other intestinal bacteria. Secondary objectives were the effects on stool characteristics, growth, and general well‐being.

Participants and Methods:

In a multicenter, double‐blind study, 159 healthy infants, formula‐fed at enrollment (at 4–6 months), were randomized to an experimental follow‐on formula supplemented with 5 g/L (GOS) (77 infants), or to a standard follow‐on formula (control, 82 infants). Infants were evaluated at enrollment (study day 1 = sd1), after 6 weeks (study day 2 = sd2), and after an additional 12 weeks (study day 3 = sd3). At each study day, a fresh stool sample for the bacterial counts was collected, and the growth parameters were measured. At sd2, urinary specimens were collected for the evaluation of urinary osmolarity.

Results:

At sd2 and sd3, the GOS group had a higher median number (colony‐forming units per gram of stool) of bifidobacteria than did the control group (sd2 GOS 9.2 × 109 vs control 4.4 × 109, P = 0.012); (sd3 GOS 7.2 × 109 vs control 2.4 × 109, P = 0.027). Other bacteria did not show any significant differences between the 2 groups at all study days. The GOS produced softer stools but had no effect on stool frequency. The urinary osmolarity (mOsm/L) at sd2 was comparable in both groups. Supplementation had no influence on the incidence of gastrointestinal side effects or on the growth of the infants.

Conclusions:

These data indicate that the addition of GOS (5 g/L) to a follow‐on formula positively influences the bifidobacteria flora and the stool consistency in infants during the supplementation period at weaning. No local or systemic side effects were recorded.
Cytokine Responses in Very Low Birth Weight Infants Receiving Glutamine‐enriched Enteral Nutrition
Authors: van den Berg Anemone , van Elburg Ruurd M , Vermeij Linda , van Zwol Annelies , van den Brink Gijs R , Twisk Jos WR , Nieuwenhuis Edward ES , Fetter Willem PF
Published: January 2009

Objective:

Very low birth weight (VLBW) infants receiving glutamine‐enriched enteral nutrition may present with a lower infection rate, which may result from enhanced antimicrobial innate or Th1 cytokine responses. We investigated whether glutamine‐enriched enteral nutrition in VLBW infants increased these cytokine responses following in vitro stimulation of whole blood cells.

Methods:

In a double‐blind, placebo‐controlled, randomized controlled trial, VLBW infants (gestational age <32 weeks and/or birth weight <1500 g) received enteral glutamine supplementation (0.3 g · kg−1 · day−1) or isonitrogenous placebo supplementation (alanine) between days 3 and 30 of life. Cytokine responses following in vitro whole blood cell stimulation with anti‐(α)CD3/αCD28 or lipopolysaccharide were analyzed by cytometric bead array at 3 time points: before the start of the study, at day 7 of life, and at day 14 of life.

Results:

Baseline patient and nutritional characteristics were not different between groups. At least 2 blood samples were analyzed in 25 of 52 (48%) and 38 of 50 (76%) infants in the glutamine‐supplemented and control groups, respectively. Glutamine‐enriched enteral nutrition was not associated with significant alterations in cytokine responses (interferon‐γ, tumor necrosis factor‐α, interleukin [IL]‐2, IL‐4, IL‐5, and IL‐10) of peripheral blood cells upon stimulation with either anti‐αCD3/αCD28 or lipopolysaccharide.

Conclusions:

We hypothesize that glutamine‐enriched enteral nutrition decreases the infection rate in VLBW infants by influencing the mucosal and not the systemic immune system.
Interactions between prefrontal cortex and cerebellum revealed by trace eyelid conditioning
Authors: Kalmbach Brian E. , Ohyama Tatsuya , Kreider Joy C. , Riusech Frank , Mauk Michael D.
Published: January 2009

Eyelid conditioning has proven useful for analysis of learning and computation in the cerebellum. Two variants, delay and trace conditioning, differ only by the relative timing of the training stimuli. Despite the subtlety of this difference, trace eyelid conditioning is prevented by lesions of the cerebellum, hippocampus, or medial prefrontal cortex (mPFC), whereas delay eyelid conditioning is prevented by cerebellar lesions and is largely unaffected by forebrain lesions. Here we test whether these lesion results can be explained by two assertions: (1) Cerebellar learning requires temporal overlap between the mossy fiber inputs activated by the tone conditioned stimulus (CS) and the climbing fiber inputs activated by the reinforcing unconditioned stimulus (US), and therefore (2) trace conditioning requires activity that outlasts the presentation of the CS in a subset of mossy fibers separate from those activated directly by the CS. By use of electrical stimulation of mossy fibers as a CS, we show that cerebellar learning during trace eyelid conditioning requires an input that persists during the stimulus-free trace interval. By use of reversible inactivation experiments, we provide evidence that this input arises from the mPFC and arrives at the cerebellum via a previously unidentified site in the pontine nuclei. In light of previous PFC recordings in various species, we suggest that trace eyelid conditioning involves an interaction between the persistent activity of delay cells in mPFC-a putative mechanism of working memory-and motor learning in the cerebellum.
Gene and Metabolite Regulatory Network Analysis of Early Developing Fruit Tissues Highlights New Candidate Genes for the Control of Tomato Fruit Composition and Development
Authors: Mounet Fabien , Moing Annick , Garcia Virginie , Petit Johann , Maucourt Michael , Deborde Catherine , Bernillon Stéphane , Le Gall Gwénaëlle , Colquhoun Ian , Defernez Marianne , Giraudel Jean-Luc , Rolin Dominique , Rothan Christophe , Lemaire-Chamley Martine
Published: January 2009

Variations in early fruit development and composition may have major impacts on the taste and the overall quality of ripe tomato (Solanum lycopersicum) fruit. To get insights into the networks involved in these coordinated processes and to identify key regulatory genes, we explored the transcriptional and metabolic changes in expanding tomato fruit tissues using multivariate analysis and gene-metabolite correlation networks. To this end, we demonstrated and took advantage of the existence of clear structural and compositional differences between expanding mesocarp and locular tissue during fruit development (12–35 d postanthesis). Transcriptome and metabolome analyses were carried out with tomato microarrays and analytical methods including proton nuclear magnetic resonance and liquid chromatography-mass spectrometry, respectively. Pairwise comparisons of metabolite contents and gene expression profiles detected up to 37 direct gene-metabolite correlations involving regulatory genes (e.g. the correlations between glutamine, bZIP, and MYB transcription factors). Correlation network analyses revealed the existence of major hub genes correlated with 10 or more regulatory transcripts and embedded in a large regulatory network. This approach proved to be a valuable strategy for identifying specific subsets of genes implicated in key processes of fruit development and metabolism, which are therefore potential targets for genetic improvement of tomato fruit quality.
High-resolution spectroscopy on an X-ray absorption beamline
Authors: Hazemann Jean-Louis , Proux Olivier , Nassif Vivian , Palancher Hervé , Lahera Eric , Da Silva Cécile , Braillard Aurélien , Testemale Denis , Diot Marie-Ange , Alliot Isabelle , Del Net William , Manceau Alain , Gélébart Frédéric , Morand Marc , Dermigny Quentin , Shukla Abhay
Published: January 2009

A bent-crystal spectrometer based on the Rowland circle geometry has been installed and tested on the BM30b/FAME beamline at the European Synchrotron Radiation Facility to improve its performances. The energy resolution of the spectrometer allows different kinds of measurements to be performed, including X-ray absorption spectroscopy, resonant inelastic X-ray scattering and X-ray Raman scattering experiments. The simplicity of the experimental device makes it easily implemented on a classical X-ray absorption beamline. This improvement in the fluorescence detection is of particular importance when the probed element is embedded in a complex and/or heavy matrix, for example in environmental sciences.
Phosphorus L
2,3-edge XANES: overview of reference compounds
Authors: Kruse Jens , Leinweber Peter , Eckhardt Kai-Uwe , Godlinski Frauke , Hu Yongfeng , Zuin Lucia
Published: January 2009

Synchrotron-based X-ray absorption near-edge structure (XANES) spectroscopy is becoming an increasingly used tool for the element speciation in complex samples. For phosphorus (P) almost all XANES measurements have been carried out at the K-edge. The small number of distinctive features at the P K-edge makes in some cases the identification of different P forms difficult or impossible. As indicated by a few previous studies, the P L
2,3-edge spectra were richer in spectral features than those of the P K-edge. However, experimentally consistent spectra of a wide range of reference compounds have not been published so far. In this study a library of spectral features is presented for a number of mineral P, organic P and P-bearing minerals for fingerprinting identification. Furthermore, the effect of radiation damage is shown for three compounds and measures are proposed to reduce it. The spectra library provided lays a basis for the identification of individual P forms in samples of unknown composition for a variety of scientific areas.