bluuebunny/crossref_metadata_2025 huggingface dataset:
Photoemission of Alq3 and C60 films on Al and LiF∕Al substrates
Authors: Jönsson S. K. M. , Salaneck W. R. , Fahlman M.
Published: June 2005

Photoemission studies of thin films of Alq3 and C60 deposited on Al and LiF∕Al substrates have been performed in order to deduce the interactions of the organic films with the substrates. For all cases there is evidence of strong interaction resulting in the formation of interfacial dipoles. Attempts to explain the origin of these interfacial dipoles and the type of interface formed in each case have been done through analysis of the valence electronic structure and core levels of the materials. The origin of the interfacial dipoles is mainly covalent interaction when the organic films are deposited on Al substrates, and charge transfer between the organic molecules and the metal through the LiF sandwich layer when the organic films are deposited on LiF∕Al substrates. For thick-enough LiF films, however, there is no interaction between the organic films and the substrates. In no case does the LiF dissociate, unlike what is found for the reverse order of deposition. Two charge-transfer-induced gap states are found for (sub)monolayer films of Alq3 deposited on LiF∕Al. We propose that the formation of two gap states corresponds to negatively charged fac-Alq3.
Wavelength-tunable (1.55-μm region) InAs quantum dots in InGaAsP∕InP (100) grown by metal-organic vapor-phase epitaxy
Authors: Anantathanasarn S. , Nötzel R. , van Veldhoven P. J. , Eijkemans T. J. , Wolter J. H.
Published: June 2005

Growth of wavelength-tunable InAs quantum dots (QDs) embedded in a lattice-matched InGaAsP matrix on InP (100) substrates by metal-organic vapor-phase epitaxy is demonstrated. As∕P exchange plays an important role in determining QD size and emission wavelength. The As∕P exchange reaction is suppressed by decreasing the QD growth temperature and the V∕III flow ratio, reducing the QD size and emission wavelength. The As∕P exchange reaction and QD emission wavelength are then reproducibly controlled by the thickness of an ultrathin [zero to two monolayers (MLs)] GaAs interlayer underneath the QDs. An extended interruption after GaAs interlayer growth is essential to obtain well-defined InAs QDs. Submonolayer GaAs coverages result in a shape transition from QD to quantum dash at low V∕III flow ratio with a slightly shorter emission wavelength. Only the combination of reduced growth temperature and V∕III flow ratio with the insertion of GaAs interlayers above ML thicknesses allows wavelength tuning of QDs at room temperature in the technologically important 1.55-μm wavelength region for fiber-optical telecommunication systems. A GaAs interlayer thickness just above one ML produces the highest photoluminescence (PL) efficiency. Temperature-dependent PL measurements reveal zero-dimensional carrier confinement and defect-free InAs QDs.
Blueshift of optical band gap in ZnO thin films grown by metal-organic chemical-vapor deposition
Authors: Tan S. T. , Chen B. J. , Sun X. W. , Fan W. J. , Kwok H. S. , Zhang X. H. , Chua S. J.
Published: June 2005

The optical band gap of ZnO thin films deposited on fused quartz by metal-organic chemical-vapor deposition was studied. The optical band gap of as-grown ZnO blueshifted from 3.13to4.06eV as the growth temperature decreased from 500to200°C. After annealing, the optical band gap shifted back to the single-crystal value. All the ZnO thin films studied show strong band-edge photoluminescence. X-ray diffraction measurements showed that samples deposited at low temperatures (<450°C) consisted of amorphous and crystalline phases. The redshift of the optical band gap back to the original position after annealing was strong evidence that the blueshift was due to an amorphous phase. The unshifted photoluminescence spectra indicated that the luminescence was due to the crystalline phase of ZnO, which was in the form of nanocrystals embedded in the amorphous phase.
Bipolar charge transport, injection, and trapping studies in a model green-emitting polyfluorene copolymer
Authors: Poplavskyy Dmitry , Su Wencheng , So Franky
Published: June 2005

Experimental studies of charge injection and transport of holes and electrons in LUMATION™ Green 1300 Series light-emitting polymer (LEP) by a combination of experimental techniques are reported. It is found that hole mobility is lower than electron mobility and the former exhibits steeper electric-field dependence thus reducing the misbalance between charge mobilities at higher device operating voltages. An approach to quantitatively analyze charge injection and trapping in organic semiconductors is proposed. Based on our analysis, hole current is limited by injection from the anode and trapping in the bulk of the polymer. Further, we found that hole trapping is approximately independent of electric field and injection efficiency increases with increasing electric field. Injection limitation of holes from poly(3,4-ethylenedioxythiophene)/polystyrenesulphonic acid (PEDOT:PSS) electrode is believed to be the result of nonuniform contact between the PEDOT:PSS and LEP rather than the energy barrier. On the other hand, electron injection is close to ohmic and the steady-state electron current is affected by trapping, mainly due to deep traps prevailing at low electric fields and with an estimated concentration of 1016cm−3. Electron trapping is found to be significantly reduced in dual-carrier devices, which is believed to be the effect of faster exciton formation and recombination rates, compared to electron trapping processes.
Oscillatory behavior of gigahertz oscillators based on multiwalled carbon nanotubes
Authors: Liu P. , Zhang Y. W. , Lu C.
Published: June 2005

Mechanical oscillatory behavior of multiwalled carbon-nanotube-based oscillators is investigated using molecular-dynamics simulations. The second-generation reactive bond-order potential and a Morse-type van der Waals potential based on the local-density approximation are used to describe bonding and nonbonding atomic interactions, respectively. It is found that the oscillatory frequency saturates as the number of outer tubes reaches three. The simulations show that the oscillatory frequency, amplitude decay rate, and stability of the oscillators depend on the diameter and helicity of the outer tubes, the extrusion distance, as well as the length of the outer tubes.
Strain-induced enhancement of near-infrared absorption in Ge epitaxial layers grown on Si substrate
Authors: Ishikawa Yasuhiko , Wada Kazumi , Liu Jifeng , Cannon Douglas D. , Luan Hsin-Chiao , Michel Jurgen , Kimerling Lionel C.
Published: June 2005

Epitaxially grown Ge layers on Si substrate are shown to reveal an enhanced absorption of near-infrared light, which is effective for the photodiode application in Si-based photonics. Ge layers as thick as 1μm were grown on Si substrate by ultrahigh-vacuum chemical-vapor deposition with a low-temperature buffer layer technique. X-ray-diffraction measurements showed that the Ge layer possesses a tensile strain as large as 0.2%, which is generated during the cooling from the high growth temperature due to the thermal-expansion mismatch between Ge and Si. Photoreflectance measurements showed that the tensile strain reduces the direct band-gap energy to 0.77 eV (c.f. 0.80 eV for unstrained Ge), as expected from the theory. Reflecting the band-gap narrowing, photodiodes fabricated using the Ge layer revealed an enhanced absorption of near-infrared light with the photon energy below 0.80 eV, i.e., with the wavelength above 1.55μm. This property is effective to apply the photodiodes to the L band (1.56–1.62μm) in the optical communications as well as the C band (1.53–1.56μm). It is shown that the experimental absorption spectrum agrees with the theoretical one taking into account the splitting of light-hole and heavy-hole valence bands accompanied by the band-gap narrowing. Based on the calculation, the performance of the photodiode using the tensile-strained Ge is discussed.
Hydrogen bonding and dynamics of methanol by high-pressure diamond-anvil cell NMR
Authors: Okuchi Takuo , Cody George D. , Mao Ho-kwang , Hemley Russell J.
Published: June 2005

Liquid methanol at densities up to ρ∕ρ0=1.7 was studied by NMR in a specially designed diamond-anvil cell. Methyl and hydroxyl resonances have been separately observed at pressures to 43kbars which exceeds equilibrium freezing pressure of methanol. The chemical shift difference between methyl and hydroxyl protons increases nonlinearly with increasing density, indicating a noticeable decrease in hydrogen bond length. The analyses of spin-lattice relaxation rates of both hydroxyl and methyl protons indicate that compression enhances intermolecular proton exchange and selectively reduces motion of the hydroxyl protons. Collectively these observations reveal that hydrogen bonding interaction in liquid methanol noticeably increases with compression, inhibiting the liquid-solid transition even above the freezing pressure.
On a classification of irreducible almost commutative geometries. III
Authors: Jureit Jan-Hendrik , Stephan Chtistoph , Schücker Thomas
Published: June 2005

We extend a classification of irreducible, almost commutative geometries whose spectral action is dynamically nondegenerate to internal algebras that have four simple summands.
Electro-optic phase modulator using metal-defined polymer optical waveguide
Authors: Kim Seong-Ku , Yuan W. , Geary K. , Hung Yu-Chueh , Fetterman H. R. , Lee Dong-Gun , Zhang C. , Wang C. , Steier W. H. , Park G.-C. , Kang S.-J. , Oh I.
Published: June 2005

We demonstrate metal-defined electro-optic polymer phase modulators for the first time. A metal strip patterned on top of a three-layer slab waveguide causes a strain-induced refractive index change, resulting in lateral optical mode confinement within the core layer. The strain profile, refractive indexes, and optical mode shapes of the metal defined optical waveguide are obtained analytically. Electro-optic phase modulators fabricated using this technique have a driving voltage of 5.6V, and ∼18dB of extinction ratio at 1.55μm wavelength. These results may be used in the complex design of integrated polymer optical circuits that require a simple and cheap fabrication process.
From Dichoptic to Dichotic: Historical Contrasts between Binocular Vision and Binaural Hearing
Authors: Wade Nicholas J , Ono Hiroshi
Published: June 2005

Phenomena involving vision with two eyes have been commented upon for several thousand years whereas those concerned with hearing with two ears have a much more recent history. Studies of binocular vision and binaural hearing are contrasted with respect to the singleness of the percept, experimental manipulations of dichoptic and dichotic stimuli, eye and ear dominance, spatial localisation, and the instruments used to stimulate the paired organs. One of the principal phenomena that led to studies of dichotic hearing was dichoptic colour mixing. There was similar disagreement regarding whether colours or sounds could be combined when presented to different paired organs. Direction and distance in visual localisation were analysed before those for auditory localisation, partly due to difficulties in controlling the stimuli. Instruments for investigating binocular vision, like the stereoscope and pseudoscope, were invented before those for binaural hearing, like the stethophone and pseudophone.
The Rod-and-Frame Effect: The Whole is Less than the Sum of its Parts
Authors: Li Wenxun , Matin Leonard
Published: June 2005

Since the discovery of the influence of the tilted frame on the visual perception of the orientation perceived as vertical (VPV), the frame has been treated as a unitary object—a Gestalt. We evaluated the effect of 1-line, 2-line, 3-line, and 4-line (square frame) stimuli of two different sizes, and asked whether the influence of the square frame on VPV is any greater than the additive combination of separate influences produced by the individual lines constituting the frame. We found that, for each size, the square frame is considerably less influential than the additive combination of the influences of the individual lines. The results conform to a mass action rule, in which the lengths and orientations of the individual line components are what matters and the organization of the lines into a square does not—no higher-level Gestalt property is involved in the induction effect on VPV.
Asymmetric Mislocalization of a Visual Flash Ahead of and behind a Moving Object
Authors: Watanabe Katsumi
Published: June 2005

When subjects localize a flash relative to another stationary stimulus, the flash appears displaced in the direction of nearby motion signals (position capture; Whitney and Cavanagh, 2000 Nature Neuroscience3 954–959). Our previous study had suggested that the position capture is larger for a flash presented ahead of a moving stimulus than for a flash behind it (Watanabe et al, 2003 Perception32 545–559). In the present study, I investigated the spatial asymmetry of position capture. Experiment 1 demonstrated that asymmetric position capture occurs primarily in a moving-object-centered coordinate. Experiment 2 showed evidence that the asymmetric position capture operates after individuation of single visual objects. Finally, experiment 3 demonstrated that, when attention was reduced with a dual-task procedure, the asymmetric position capture increased. These results suggest that the spatial asymmetry of position capture occurs without attention but the spatial bias can be reduced by attention. Therefore, the underlying mechanism for the asymmetric spatial bias may be different from attentive tracking (Cavanagh, 1992 Science257 1563–1565) and mislocalization during smooth pursuit (Brenner et al, 2001 Vision Research41 2253–2259).
Evaluation for farming systems improvement: looking backwards, thinking forwards
Authors: Dart J.
Published: June 2005

Based on personal reflection, this paper presents program evaluation as a vehicle to bring about better project results and perhaps even a better world. New paradigm approaches to farming systems improvement feature multiple collaborators in work that is increasingly participatory, process-oriented and diverse in outcome. This is often accompanied by pressure for rapid feedback and dialogue. Conventional objectives-based evaluation methods are insufficient to capture the range of unanticipated outcomes that this work may produce, and may be incompatible with a participatory ethos. In the contemporary farming systems improvement context, evaluation is most valuable when it has short-cycles and fosters reflection. Two contrasting techniques that offer promise for meeting these needs are the most significant change technique, and participatory approaches to program logic. Presenting a radical departure from conventional monitoring against quantitative indicators, most significant change technique involves the regular collection and participatory interpretation of ‘stories’ about change rather than predetermined quantitative indicators. Program logic is the rationale behind a program or project — what are understood to be the cause and effect relationships between project activities, outputs, intermediate outcomes, and ultimate outcomes. When done in group situations, program logic offers many benefits by enabling participants to question the cause and effect assumptions to improve project design. These techniques can supplement traditional approaches; closing some of the information gaps identified by contemporary farming systems improvement work.
Rumen fermentation characteristics of dairy cows grazing different allowances of Persian clover- or perennial ryegrass-dominant swards in spring
Authors: Williams Y. J. , Walker G. P. , Doyle P. T. , Egan A. R. , Stockdale C. R.
Published: June 2005

An experiment was conducted in which cows in early lactation grazed Persian clover (Trifolium resupinatum L.) or perennial ryegrass (Lolium perenne L.)-dominant pastures at low or high pasture allowances in order to determine the effects of pasture type and level of feeding on rumen fermentation patterns. The hypotheses for grazing dairy cows were: (i) the consumption of Persian clover would result in a more rapid rate of degradation and less stable rumen fermentation patterns compared with perennial ryegrass; and (ii) the greater intake of cows grazing at high compared with low pasture allowances would also cause less stable rumen fermentation patterns. Stability of rumen fermentation refers to the level to which rumen fluid pH declines, especially for long periods of a day, indicating that the rumen is not coping with neutralising and/or removing acids. Cows grazing Persian clover had lower (P<0.05) average daily rumen fluid pH (5.7 v. 5.9), molar proportions of acetic acid (68.3 v. 70.6%) and ratios of lipogenic to glucogenic volatile fatty acid (4.6 v. 5.1) in the rumen than those grazing perennial ryegrass. They had higher (P<0.05) rumen fluid ammonia-N (26.3 v. 13.0 mg/100 mL) and total volatile fatty acid (165 v. 134 mmol/L) concentrations and molar proportions of butyric (11.3 v. 10.7%) and propionic (17.2 v. 16.1%) acids than cows grazing perennial ryegrass. Cows grazing at low pasture allowances had a higher (P<0.05) average daily rumen fluid pH (5.9 v. 5.7) and lower rumen fluid ammonia-N (18.6 v. 20.7 mg/100 mL) and total volatile fatty acid (143 v. 156 mmol/L) concentrations than cows grazing at high pasture allowances. Cows given Persian clover at the high allowance had a rumen fluid pH less than 6.0 for the entire day while rumen fluid pH was below 6.0 for at least 15 h of the day on all the other treatments. There was no effect (P>0.05) of pasture allowance on the degradation rate of perennial ryegrass dry matter, but the higher allowance of Persian clover resulted in the highest (P<0.05) rate of degradation of dry matter compared with either ryegrass treatment or the low allowance of Persian clover. The effective dry matter degradability of Persian clover was greater (P<0.05) than that of perennial ryegrass, and the effective dry matter degradability of herbage in cows grazing at low allowances was greater (P<0.05) than at higher allowances. However, future research should consider neutral detergent fibre degradation in grazing dairy cows with low rumen fluid pH levels.
Phylogenetic evaluation of systematics and biogeography of the leech family Glossiphoniidae
Authors: Siddall Mark E. , Budinoff Rebecca B. , Borda Elizabeth
Published: June 2005

The phylogenetic relationships of Glossiphoniidae, a leech family characterised by its high degree of parental care, were investigated with the combined use of morphological data and three molecular datasets. There was strong support for monophyly of most accepted genera in the group, many of which are consistent with eyespot morphology. The genera Desserobdella Barta & Sawyer, 1990 and Oligobdella Moore, 1918 are suppressed as junior synonyms of Placobdella Blanchard, 1893 and thus recognising each of Placobdella picta (Verrill, 1872) Moore, 1906, Placobdella phalera (Graf, 1899) Moore, 1906, and Placobdella biannulata (Moore, 1900), comb. nov. The species Glossiphonia elegans (Verrill, 1872) Castle, 1900 and Helobdella modesta (Verrill, 1872), comb. nov. are resurrected for the North American counterparts to European non-sanguivorous species. Glossphonia baicalensis (Stschegolew, 1922), comb. nov. is removed from the genus Torix Blanchard 1898 and Alboglossiphonia quadrata (Moore, 1949) Sawyer, 1986 is removed from the genus Hemiclepsis Vejdovsky, 1884. The biogeographic implications of the phylogenetic hypothesis are evaluated in the context of what is already known for vertebrate hosts and Tertiary continental arrangements.
Age of acquisition for naming and knowing: A new hypothesis
Authors: Funnell Elaine , Hughes Diana , Woodcock Jayne
Published: June 2005

This paper reports an investigation into the age of acquisition of object names and object knowledge in a cross-sectional study of 288 children aged between 3 years 7 months and 11 years 6 months, comprising equal numbers of boys and girls. The objects belonged to four categories: animals, fruit and vegetables, implements, and vehicles. They were presented in three image types: line drawings, black-and-white photographs, and coloured photographs. In the knowledge test, five probe questions were asked for each object given the spoken name. Results showed that line drawings were more difficult to name than either black-and-white photographs or coloured photographs, which did not differ. The boys significantly out-performed the girls at naming and knowing, both overall and specifically for the category of vehicles. Naming and knowledge increased steadily with age but while young children below about 6 years 6 months showed an advantage to naming, older children showed an advantage to knowing. Similarly, age-of-acquisition measures for each item revealed a significant shift in the relationship between naming and knowing at around 80 months. We argue that differences in learning experience lead younger and older children to associate object names with different types of information, and we suggest that this difference probably accounts for the age-of-acquisition effects reported in adult object naming.
Memory for object location and route direction in virtual large-scale space
Authors: Janzen Gabriele
Published: June 2005

In everyday life people have to deal with tasks such as finding a novel path to a certain goal location, finding one's way back, finding a short cut, or making a detour. In all of these tasks people acquire route knowledge. For finding the same way back they have to remember locations of objects like buildings and additionally direction changes. In three experiments using recognition tasks as well as conscious and unconscious spatial priming paradigms memory processes underlying wayfinding behaviour were investigated. Participants learned a route through a virtual environment with objects either placed at intersections (i.e., decision points) where another route could be chosen or placed along the route (non-decision points). Analyses indicate first that objects placed at decision points are recognized faster than other objects. Second, they indicate that the direction in which a route is travelled is represented only at locations that are relevant for wayfinding (e.g., decision points). The results point out the efficient way in which memory for object location and memory for route direction interact.
Retrieval independence between parts and wholes in successive recognition tasks
Authors: Glass Arnold L. , Lian Arild , Buyske Steven
Published: June 2005

Participants studied AB word pairs and completed three recognition tests. In one recognition test each A word was presented with two distractors that did not appear on the study list. In another recognition test each B word was presented with two distractors that did not appear on the study list. In a third recognition test an AB target was presented with two distractors composed of words not on the study list. Six different groups of participants each performed the recognition tests in a different order, so that all possible orders were tested. Recognition of the A, B, and AB targets for a given study pair were independent of each other when single-word recognition preceded double-word recognition. There was almost complete independence in the reverse order. Even when recognition judgements were restricted to those for which the participants were most confident, there was independence of recognition among the three tests. A pair recognition test served as an additional study trial for the individual words; however, the reverse was not the case. All of these results were predicted by a single three-parameter mathematical model derived from the hypothesis that single-word and double-word targets had independent representations in memory.
Decomposing retrieval and integration in memory for actions: A multinomial modeling approach
Authors: Steffens Melanie C. , Jelenec Petra , Mecklenbräuker Silvia , Marie Thompson Erin
Published: June 2005

Typically, action phrases are recalled better if participants are asked to enact the phrases than if they are just asked to remember them. When investigating which processes constitute this enactment effect a difficulty is that observable effects in standard memory tests are ambiguous because such tests require several processes. In the present article, we introduce a multinomial model that decomposes observable memory performance into a retrieval parameter and a parameter concerning the item-specific processing and integration of an action phrase. These parameters are estimated from free recall and cued recall performance. The model fitted the data of two experiments designed to test it. Experiment 1 demonstrated the basic usefulness of the model by showing expected differences in the integration parameter in the absence of unexpected differences in the retrieval parameter. Experiment 2 extended the conditions under which the model is useful by showing expected differences in the retrieval parameter even in the presence of unexpected differences in the integration parameter. Together, these findings support our theoretical framework according to which enactment generally boosts integration of action phrases, but increases retrieval only for phrases with context cues.
Intention in motor learning through observation
Authors: Badets Arnaud , Blandin Yannick , Shea Charles H.
Published: June 2005

The purpose of this experiment was to assess whether learning an action through observation is enhanced by the intention to reproduce the observed behaviour. Two groups of participants observed a model practise a timing task and performed a 24-hour delayed retention test. Participants in the first group of observers were explicitly instructed that they would be required to execute the timing task that they had observed as accurately as possible during the delayed retention test. Observers in the second group were instructed that they would be required to describe as accurately as possible the behaviour that they had observed. A control group of participants, who did not observe the model, was also administered the delayed retention test. The results of the retention test indicated that absolute timing (parameterization) was learned by the observers to the same extent with or without intention to reproduce the task. Indeed, on the retention test absolute timing for the two groups of observers was as effective as that for the models. However, observing with an intention to reproduce the task was beneficial for learning the movement's relative timing structure. Results are discussed with respect to a potential mechanism by which intention enhances observation.
Effects of Hurricane Charley on fish chorusing
Authors: Locascio James V , Mann David A
Published: June 2005

Hurricane Charley, a category 4 hurricane, passed through Charlotte Harbor, Florida, directly over an autonomous underwater acoustic datalogger used to record sound production by fishes associated with courtship and spawning. Acoustic recordings made on 9 days prior to the storm, during and 3 days after the storm provided unprecedented documentation of the hurricane's passage and its effect on fishes' calling behaviour. The hurricane did not inhibit nightly chorusing events of spawning fish. Sound levels produced by spawning fish on the night of and 3 days after the hurricane were higher and lasted longer than any of the 9 days recorded prior to the hurricane.
Catastrophe loss modelling of storm-surge flood risk in eastern England
Authors: Muir Wood Robert , Drayton Michael , Berger Agnete , Burgess Paul , Wright Tom
Published: June 2005

Probabilistic catastrophe loss modelling techniques, comprising a large stochastic set of potential storm-surge flood events, each assigned an annual rate of occurrence, have been employed for quantifying risk in the coastal flood plain of eastern England. Based on the tracks of the causative extratropical cyclones, historical storm-surge events are categorized into three classes, with distinct windfields and surge geographies. Extreme combinations of ‘tide with surge’ are then generated for an extreme value distribution developed for each class. Fragility curves are used to determine the probability and magnitude of breaching relative to water levels and wave action for each section of sea defence. Based on the time-history of water levels in the surge, and the simulated configuration of breaching, flow is time-stepped through the defences and propagated into the flood plain using a 50 m horizontal-resolution digital elevation model. Based on the values and locations of the building stock in the flood plain, losses are calculated using vulnerability functions linking flood depth and flood velocity to measures of property loss. The outputs from this model for a UK insurance industry portfolio include ‘loss exceedence probabilities’ as well as ‘average annualized losses’, which can be employed for calculating coastal flood risk premiums in each postcode.
What is the function of the claustrum?
Authors: Crick Francis C , Koch Christof
Published: June 2005

The claustrum is a thin, irregular, sheet-like neuronal structure hidden beneath the inner surface of the neocortex in the general region of the insula. Its function is enigmatic. Its anatomy is quite remarkable in that it receives input from almost all regions of cortex and projects back to almost all regions of cortex. We here briefly summarize what is known about the claustrum, speculate on its possible relationship to the processes that give rise to integrated conscious percepts, propose mechanisms that enable information to travel widely within the claustrum and discuss experiments to address these questions.
PBAF chromatin-remodeling complex requires a novel specificity subunit, BAF200, to regulate expression of selective interferon-responsive genes
Authors: Yan Zhijiang , Cui Kairong , Murray Darryl M. , Ling Chen , Xue Yutong , Gerstein Amy , Parsons Ramon , Zhao Keji , Wang Weidong
Published: June 2005

PBAF and BAF are two chromatin-remodeling complexes of the SWI/SNF family essential for mammalian transcription and development. Although these complexes share eight identical subunits, only PBAF can facilitate transcriptional activation by nuclear receptors in vitro. Here we show that these complexes have selectivity in mediating transcription of different interferon-responsive genes. The selectivity by PBAF requires a novel subunit, BAF200, but not the previously described PBAF-specificity subunit, BAF180 (Polybromo). Our study provides in vivo evidence that PBAF and BAF regulate expression of distinct genes, and suggests that BAF200 plays a key role in PBAF function.
Not all J domains are created equal: Implications for the specificity of Hsp40–Hsp70 interactions
Authors: Hennessy Fritha , Nicoll William S. , Zimmermann Richard , Cheetham Michael E. , Blatch Gregory L.
Published: June 2005

Heat shock protein 40s (Hsp40s) and heat shock protein 70s (Hsp70s) form chaperone partnerships that are key components of cellular chaperone networks involved in facilitating the correct folding of a broad range of client proteins. While the Hsp40 family of proteins is highly diverse with multiple forms occurring in any particular cell or compartment, all its members are characterized by a J domain that directs their interaction with a partner Hsp70. Specific Hsp40–Hsp70 chaperone partnerships have been identified that are dedicated to the correct folding of distinct subsets of client proteins. The elucidation of the mechanism by which these specific Hsp40–Hsp70 partnerships are formed will greatly enhance our understanding of the way in which chaperone pathways are integrated into finely regulated protein folding networks. From in silico analyses, domain swapping and rational protein engineering experiments, evidence has accumulated that indicates that J domains contain key specificity determinants. This review will critically discuss the current understanding of the structural features of J domains that determine the specificity of interaction between Hsp40 proteins and their partner Hsp70s. We also propose a model in which the J domain is able to integrate specificity and chaperone activity.
Mononuclear cell subsets in bronchoalveolar lavage fluid duringDictyocaulus viviparusinfection of calves: a potential role for γ/δ TCR‐expressing cells in airway immune responses?
Authors: Hagberg M. , Wattrang E. , Niskanen R. , Tråvén M. , Höglund J. , Lundén A.
Published: June 2005

Mononuclear cell populations in the lungs of calves infected withDictyocaulus viviparuswere studied during primary infection and reinfection in order to identify cells involved in development of protective immunity to parasitic bronchitis. Three groups of calves were either inoculated with 500 third‐stage larvae at both weeks 0 and 10 (n = 6), inoculated only at week 10 (n = 6), or remained uninfected (n = 3). The animals were monitored weekly by collection of bronchoalveolar lavage fluid (BALF), blood and faeces. Among mononuclear BALF‐cell populations, the γ/δ TCR‐expressing cells showed a pronounced transient increase in proportion as well as in relative cell size 2 weeks post primary infection, whereas CD4‐, CD8‐, Ig‐ and CD14‐expressing cells showed no significant differences related to the infection. The increase in γ/δ TCR‐expressing cells coincided with significantly increased proportions of eosinophils and recovery of adult worms in BALF. After reinfection, γ/δ TCR‐expressing cells increased again, but not until week 3 post inoculation, whereas eosinophils were increased by week 2 and reached higher levels than after primary infection. After reinfection, establishment ofD. viviparuswas less successful than after primary infection. In conclusion, these results indicate a role for γ/δ TCR‐expressing lymphocytes in the pathogenesis ofD. viviparusinfection.
Parasite‐specific IgM plays a significant role in the protective immune response to asexual erythrocytic stage Plasmodium chabaudi AS infection*
Authors: Couper K. N. , Phillips R. S. , Brombacher F. , Alexander J.
Published: June 2005

A comparison of Plasmodium chabaudi AS infection in BALB/c and BALB/c IgM‐deficient mice demonstrated a protective role for IgM during infection. IgM−/– mice, unlike µMT mice, display competent B cell humoral immune responses. Increased susceptibility of IgM−/– mice was demonstrated by increased mortality, an advanced ascending infection and higher peak parasitaemia, as well as enhanced anaemia and weight loss compared with wild‐type mice. The recrudescent parasitaemias were also higher in the IgM−/– mice. Early specific IgM production in P. chabaudi‐infected wild‐type mice was followed by IgG1 and IgG2a production, while IgG1 and IgG2a production in IgM−/– mice was preceded by specific IgD production. No protective role for natural IgM against P. chabaudi AS infection was detected as passive transfer of naïve WT serum into IgM−/– mice did not alter the disease outcome or reduce parasite numbers. Passive transfer of WT antiserum, containing predominantly specific IgM, into IgM−/– mice delayed the ascending parasitaemia and reduced mortality. Similarly, coating parasitized red blood cells with WT antiserum, but not IgM−/– antisera, prior to infection also slightly delayed the ascending acute parasitaemia. Specific IgM therefore plays an important role in the limitation of parasite replication during asexual erythrocytic P. chabaudi AS infection.
Infants' symbolic comprehension of actions modeled with toy replicas
Authors: Johnson Kathy E. , Younger Barbara A. , Furrer Stephanie D.
Published: June 2005

While very young children's understanding of objects as symbols for other entities has been the focus of much investigation, very little is known concerning the emergence of comprehension for symbolic relations among actions modeled with toy replicas and their real counterparts. We used videotaped depictions of real actions in a preferential looking task to assess toddlers’ ability to comprehend such connections for action categories aligned with familiar object concepts. Across two experiments, 16‐ and 18‐month‐olds provided no evidence of understanding such relations, even when action categories were highlighted with verbal prompts. Among 24‐ and 26‐month‐olds, comprehension of relations between certain actions modeled with toys and videos of their real‐world counterparts began to emerge, independent of expressive vocabulary size. Implications of our results for theoretical conclusions drawn from use of the generalized imitation procedure to study early conceptual development are discussed.
Motion and color processing in school‐age children and adults: an ERP study
Authors: Coch Donna , Skendzel Wendy , Grossi Giordana , Neville Helen
Published: June 2005

Stimuli designed to selectively elicit motion or color processing were used in a developmental event‐related potential study with adults and children aged 6, 7 and 8. A positivity at posterior site INZ (P‐INZ) was greater to motion stimuli only in adults. The P1 and N1 were larger to color stimuli in both adults and children, but earlier to motion stimuli only in adults. Finally, the P2 was larger to color stimuli in adults but larger to motion stimuli in children, and earlier to motion stimuli only in children. The findings across components indicate development from middle childhood to adulthood in aspects of both the motion and color processing systems indexed by this paradigm, but are consistent with an hypothesis of a more protracted time course of development for the motion as compared to the color processing system.
Extensive nodular cutaneous amyloidosis: an unusual presentation
Authors: Criado PR , Silva CS , Vasconcellos C , Valente NYS , Maito JB
Published: June 2005

Amyloidosis is characterized by the deposition of a group of unrelated proteins leading to changes in tissue architecture and function. The nodular variant is the rarest form of the cutaneous amyloidoses. We report a patient with localized nodular amyloidosis without systemic amyloid involvement or paraproteinaemia after 6 years of follow‐up. The unusual aspects of our case were a plaque presentation rather than nodular, and the disseminated pattern observed.
Impetigo herpetiformis: menstrual exacerbations for 7 years postpartum
Authors: Chaidemenos G , Lefaki I , Tsakiri A , Mourellou O
Published: June 2005

Impetigo herpetiformis (IH) is a rare pustular dermatosis that shares striking clinical and histological similarities to generalized pustular psoriasis. The case of a 26‐year‐old primigravida with IH progressing in the 30th week of her pregnancy is presented. The peculiarity of our presentation relies on the reappearance of the disease postpartum. Monthly exacerbations during menstruation lasted for 7 years. Some probable clues regarding the pathogenesis of IH are suggested.
Language study in higher education and the development of criticality1
Authors: Brumfit Christopher , Myles Florence , Mitchell Rosamond , Johnston Brenda , Ford Peter
Published: June 2005

This article explores the development of criticality in Modern Languages graduates in the UK. It is based on a larger research project investigating the development of criticality in (initially) two academic disciplines through the detailed analysis of a large corpus of qualitative data. This includes student interviews, teacher interviews, classroom observation, written and oral work produced by students, documentation produced for courses, and policy statements from national and institutional sources. This article focuses on the relationship between the Modern Languages curriculum, particularly language teaching and learning, and the development of criticality. Drawing upon evidence from the qualitative data, it outlines the ways in which the courses can be seen to contribute to the development of wider social competences. Finally it discusses the distinctiveness of the contribution to criticality development provided by the cross‐cultural and cross‐linguistic experience of Modern Languages undergraduates.
Clinical Subtypes of Cluster Headache and Response to Lithium Therapy
Authors: Mathew Ninan T.
Published: June 2005

SYNOPSIS

Based on clinical features, a group of 31 patients with cluster headache was divided into 1) episodic cluster headache, with months or years of headache free intervals, 2) chronic cluster headache without significant headache free intervals. Chronic type could be subdivided into primary and secondary varieties, secondary being a transformation from episodic cluster headache. A clinical trial of Lithium Carbonate was undertaken. Blood levels of lithium were determined at regular intervals to monitor the therapeutic dosage. Lithium was found to be an effective prophylactic agent in both episodic and chronic cluster headache patients. The percentage of improvement based on headache index was as follows: 55% of patients had more than 90% improvement; 10% of patients showed 60–90% improvement; 15% of patients showed 25–60% improvement; and 20% no improvement. Effectiveness of lithium was evident in less than a week after the initiation of treatment in those who responded. 55% of patients showed mild side effects such as tremor, nausea, diarrhea, abdominal discomfort and lethargy. Only one patient had serious side effects which needed discontinuation of therapy.The beneficial effect of lithium on cluster headaches appear to be independent of its anti‐depressant action. Mechanism of action of lithium in cluster headache is not clear.
A Comparative Trial of Ergotamine Tartrate, Acetyl Salicylic Acid and a Dextropropoxyphene Compound in Acute Migraine Attacks
Authors: Hakkarainen Heikki , Gustafsson Bengt , Stockman Olof
Published: June 2005

SYNOPSIS

The effect of a dextropropoxyphene compound (Doleron(r)) was compared with that of ergotamine tartrate and acetyl salicylic acid on 525 acute migraine attacks in a double blind study of 25 adult female patients. Ergotamine and the dextropropoxyphene compound were approximately equally effective and significantly superior to acetyl salicylic acid in preventing the attacks entirely. In the cases in which the attack was only partially prevented, the dextropropoxyphene compound was more effective than ergotamine and acetyl salicylic acid in making the attacks milder and shorter. Side effects, especially gastrointestinal symptoms and fatigue, were less common with the dextropropoxyphene compound than from either of the two drugs. Probably for this reason, the patients' overall preference was clearly in favor of the dextropropoxyphene compound. The addition of dextropropoxyphene, a centrally active analgesic, to acetyl salicylic acid, gives an antimigraine compound which has an efficacy comparable with ergotamine but with less side effects.
Pediatric Headaches: A One Year Retrospective Analysis
Authors: Jay Gary W. , Tomasi Lawrence G.
Published: June 2005

SYNOPSIS

Epidemiologically, headaches are common in children. In order to ascertain the type of headache problems that result in a referral by pediatricians to a pediatric neurology clinic, the charts were reviewed of all patients evaluated in 1978 with the diagnosis of headache.A chief complaint of headache was given in 116 (22%) of all new patients evaluated. Final diagnostic groups were migraine headaches or variants (47%), tension headaches (28%), seizure equivalent (15%) and miscellaneous (10%). Almost two thirds of the patients were female. The mean ages of the seizure equivalent group and the tension headache group were similar, 9.3 and 9.5 years respectively. The migraine group was older with a mean age of 9.8 years. Of the 54 patients with migraine headaches, 78% were characterized as common migraine. This evaluation of the migraine patients differed from that of patients considered to have seizure equivalents on the basis of family history (63% vs 12%), abnormalities noted on neurological examination (7% vs 24%) and EEG abnormalities (20% vs 84%). Abnormalities in the tension headache group were less than 10% in all three categories evaluated.Although some overlaps exist, these data suggest a bimodel curve with migraine headaches and recurrent seizures at the extreme ends of the spectrum rather than a single entity with varying manifestations. Historically, the family history is the most distinguishing characteristic, but abnormalities on neurological evaluation, especially the EEG, were considered more significant factors in arriving at a diagnosis.
L‐Dopa Effect on Prolactin Plasma Levels in Complicated and Common Migrainous Patients
Authors: Vardi J. , Flechter S. , Ayalon D. , Cordova T. , Oberman Z.
Published: June 2005

SYNOPSIS

Dopamine is known as an inhibitor of Prolactin (PRL) secretion; Prostaglandin F 2a is known as a stimulatorof its production. These effects probably occur at the hypophisis. Prostaglandins are thought to be involved inthe mechanism of migraine attacks. Prolactin response (as plasma levels) to L‐dope inhibitory test wasmeasured in migrainous patients. Two different Prolactin curves were obtained during the migrainous attacks,according to the type of the migraine, common and complicated.It was found that during an attack of a common migraine, Prolactin plasma levels were reduced in responseto L‐dope loading test, while during an attack of complicated migraine a hyperprolactinemic curve wasobtained.The significant difference elaborated statistically, can not be explained by one single factor, like serotonin,which is supposed to be involved in the mechanism of both types of migraine; therefore we have to assumethat another factor associated with Prolactin secretion is specifically connected to complicated type ofmigraine. It is suggested that the hyperprolactinemic responses may indicate an interaction between L‐dopaand Prostaglandin F 2a , and should be considered as an indirect evidence that Prostaglandin F 2a is involved inthe mechanism of the complicated migraine attacks, but not in common migraine.
The Value of Biofeedback in the Treatment of Chronic Headache: a Four‐year Retrospective Study
Authors: Diamond Seymour , Montrose David
Published: June 2005

SYNOPSIS

A four‐year retrospective study was completed with 693 headache patients who had completed a specific biofeedback training program. Patients 18 years of age and over were also given a Minnesota Multiphasic Personality Inventory to determine psychopathology, depression and anxiety levels, difficulty to motivate, and dependency. The purpose was to examine the long‐term effects of biofeedback training on headache problems. Patients seen between January 1977 and December 1980, ages 6 through 72, with migraine, muscle contraction, mixed migraine and muscle contraction, and cluster headache were mailed an invisibly‐coded 20‐item questionnaire.The effect of such variables as age at time of training, sex, headache diagnosis, elapsed time since training, periodic follow‐up (number of sessions), temperature training with instrumentation reinforcement and relaxation homework, the warm, supportive clinician/therapist relationship with positive expectations for the patient's success, and personality and psychological factors are predictive of success in the application of biofeedback to headache is discussed.