bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Styrene/Butyl Acrylate Linear and Star Block Copolymers via Atom Transfer Radical Polymerization
Authors: Huang Jinyu , Jia Shijun , Siegwart Daniel J. , Kowalewski Tomasz , Matyjaszewski Krzysztof 
Published: April 2006

AbstractSummary: Well‐defined styrene (S) and butyl acrylate (BA) linear and star‐like block copolymers are synthesized via atom transfer radical polymerization (ATRP) using di‐ and trifunctional alkyl halide initiators employing the Cu/PMDETA (N,N,N′,N″,N″‐pentamethyldiethylenetriamine) catalyst system. Initial addition of CuII deactivator and utilization of halogen exchange techniques suppresses the coupling of radicals and improves cross‐propagation to a large extent, which results in better control over the polymerization. Two types of star‐like PBA/PS block copolymers are prepared by using core‐first techniques: a trifunctional PBA or PS macroinitiator extended with the other monomer. Block copolymers with a well‐defined structure and low polydispersity (PDI = $\overline M _{\rm w} /\overline M _{\rm n}$) are obtained in both cases. A trifunctional PBA3 macroinitiator with $\overline M _{\rm n}$ = 136 000 g · mol−1 and PDI = 1.15 is extended to (PBA‐PS)3 star‐like block copolymer with $\overline M _{\rm n}$ = 171 100 g · mol−1 and PDI = 1.15. A trifunctional PS3 macroinitiator with $\overline M _{\rm n}$ = 27 000 g · mol−1 and PDI = 1.16 g · mol−1 is extended to (PS‐PBA)3 with $\overline M _{\rm n}$ = 91 500 g · mol−1 and PDI = 1.40. The individual star‐like macromolecules as well as their aggregates are visualized by atomic force microscopy (AFM) where the PS and PBA adopt the globular and extended conformation, respectively. For the PBA core star block copolymers, PS segments tend to aggregate either intramolecularly or intermolecularly. PS core star block copolymers form aggregates with a PS core and emanating PBA chains. Most aggregates have ‘n × 3’ arms but minor amounts of ‘defective’ stars with 4, 5, 8, or 11 arms are also observed. The AFM analysis shows that PS core star block copolymers contain about 92% three‐arm block copolymers, and the efficiency of cross‐propagation is 97.3%.Schematic representation of the synthesis of BA/S star‐like block copolymers by ATRP, and their resultant AFM images.imageSchematic representation of the synthesis of BA/S star‐like block copolymers by ATRP, and their resultant AFM images.
A study of the influence of tunnel oxide thickness on the performance of flash memory based on ion‐beam synthesized silicon nanocrystals
Authors: Ng C. Y. , Chen T. P. , Du A. 
Published: April 2006

AbstractIn this work, we have fabricated silicon nanocrystal (nc‐Si) based Flash memories with two different tunnel‐oxide thicknesses (3 and 7 nm). The nc‐Si is synthesized with very‐low energy ion implantation and subsequent thermal annealing. The endurance and retention characteristics of the memory devices are investigated. For the thick tunnel oxide (7 nm), a memory window of ∼0.5 V is achieved with the program/erase (P/E) operation at +12 V/–12 V for 1 ms; and for the thin tunnel oxide (3 nm), a memory window of ∼0.6 V can be obtained at +9 V/–9 V for 1 μs. For both oxide thicknesses, good endurance with a small threshold voltage drift after 105 P/E cycles is observed. For the thick and thin tunnel oxides, the device is expected to show ∼20% and ∼70% charge loss after 10 years, respectively. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural resilience of Cu nanoclusters deposited softly on an Au(001) surface
Authors: Jiménez‐Sáez J. C. , Pérez‐Martín A. M. C. , Jiménez‐Rodríguez J. J. 
Published: April 2006

AbstractThe soft deposition of Cu clusters with Wulff‐shape on an Au(001) surface is studied by constant‐temperature molecular dynamics. The influence of the kinetic energy, the substrate, the temperature and the cluster orientation is analyzed. Bombardment energy ranges between 1 and 100 meV/atom. At low energy the deposition is mainly elastic, while at higher it is plastic. Randomly rotated clusters suffer a less violent collision. Only in some aligned clusters, epitaxia is found. In the rest of systems, the [$ 00 \bar 1 $] axis of the cluster is at an angle of 45° to the same axis of the substrate. The temperature modifies the horizontal planes such that the Cu main grain matches to the substrate surface. The number of grains is larger in the aligned systems at low temperature. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Predicting the low energy landscape of nanoscale silica using interatomic potentials
Authors: Bromley S. T. 
Published: April 2006

AbstractThe energies of 52 of the lowest lying structural isomers of the (SiO2)12 nanocluster are accurately calculated via energy minimisations employing density functional theory (DFT) and also with two silica interatomic potentials (IPs). Of the tested IPs, one was specifically parameterised with respect to small silica nanoclusters, and the other was biased to accurately recover bulk silica properties, although having been applied numerous times to silica nanosystems. The predicted energetic ordering of the nanocluster isomers resulting from the IP optimisations are compared with respect to their deviance from benchmark nanocluster energies from DFT calculations. Although both IPs predict the DFT ground state isomer to be a very low energy cluster and thus are of use in global optimisation studies, large fluctuations in the IP energies of other low lying isomers (relative to the respective DFT energies) shed doubt on their wider applicability to nanoscale silica systems. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic properties of nanocrystalline FeNiN thin films
Authors: Prieto P. , Camarero J. , Sacristan N. , Boerma D. O. , Sanz J. M. 
Published: April 2006

AbstractFeNiN thin films with a Ni content varying between 5 and 36 at% (as determined by X‐ray photoelectron spectroscopy) have been deposited in a Dual Ion Beam Sputtering System at room temperature. The structure and crystalline size were studied by X‐ray diffraction while the magnetic properties were investigated by vectorial kerr magnetometry. In general, the deposited films present a nanocrystaline cubic structure and well defined in‐plane magnetic anisotropy. The variation of the magnetic properties was attributed to changes in composition and nanocrystalline structure. FeNiN thin films with a Ni content of about 15 at% show the better soft magnetic properties with a minimum in the coercivity of 9 Oe. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Evaluation of anxiolytic activity of spray dried powders of two South Brazilian Passiflora species
Authors: Reginatto Flávio H. , De‐Paris Fernanda , Petry Raquel D. , Quevedo João , Ortega George González , Gosmann Grace , Schenkel Eloir P. 
Published: April 2006

AbstractThe Passiflora extracts have been used in folk medicine because of its reputed sedative and anxiolytic properties. The present study aimed to compare the potential anxiolytic activity of two Passiflora spray‐dried powders obtained from P. alata and P. edulis, known in Brazil as ‘maracujá’. Male adult Swiss rats were treated with 200, 400 and 800 mg/kg of spray‐dried powders p.o. and anxiolytic activity was evaluated using the elevated plus‐maze test. The spray‐dried powders showed anxiolytic activity in doses of 400 and 800 mg/kg. Our results support the potential anxiolytic effect of Passiflora spray‐dried powders (P. alata and P. edulis). Copyright © 2006 John Wiley & Sons, Ltd.
Protective effects of sugar cane extract on endotoxic shock in mice
Authors: Motobu Maki , Amer Said , Koyama Yukari , Hikosaka Kenji , Sameshima Toshiya , Yamada Manabu , Nakamura Kikuyasu , Koge Kenji , Kang Chung‐Boo , Hayasidani Hideki , Hirota Yoshikazu 
Published: April 2006

AbstractSugar cane extract (SCE) has been shown to have an immunostimulating effect in chickens. This study evaluated the effect of SCE on Salmonella Abortusequi lipopolysaccharide (LPS)‐induced lethal shock in d‐galactosamine (GalN)‐sensitized mice. Mice were administered intraperitoneally SCE (500 mg/kg) or phosphate buffered saline before or after injection of LPS and GalN. All the mice injected with LPS and GalN (control group) died of histopathologically congestive and hemorrhagic hepatic insufficiency within 24 h, showing significantly increased activities of plasma aspartate aminotransferase (AST; 380 IU/mL) and alanine aminotransferase (ALT; 130 IU/mL). Pretreatment of mice with SCE at 3 h before challenge with LPS and GalN (SCE treated group) resulted in significantly improved survival rates (92.3%) and a decrease in liver injury. These surviving mice in the SCE treated group showed no changes in the mean levels of plasma AST (60 IU/mL) and ALT (18 IU/mL). However, the level of tumor necrosis factor‐α in the SCE treated group was not significantly different when compared with that in the control group challenged with LPS and GalN. These results suggest that SCE has protective effects on LPS‐induced mortality in this mouse model. Copyright © 2006 John Wiley & Sons, Ltd.
St John's wort modulation and developmental expression of multidrug transporters in the rat
Authors: Garrovo Chiara , Rosati Anna , Bartoli Fiora , Decorti Giuliana 
Published: April 2006

AbstractExtracts of St John's wort (SJW) (Hypericum perforatum) are a potent inducer of enzymes of the cytochrome P450 system and of the transport protein P‐glycoprotein, and interactions with a range of commonly prescribed medications have been described. In addition, recent experimental data suggest that, this otherwise safe treatment, could have some side effects when consumed during pregnancy and lactation.The aim of this study was to investigate, in Wistar rats, the effect of a treatment with high doses of SJW extract (100 and 1000 mg/kg/day) administered prenatally and during breastfeeding, on the level of transcripts of mdr1a, mdr1b, mrp1, mrp2 and cyp3A2 genes.All transcripts were detected in the liver, and their level of expression increased from fetuses to adults. SJW administration, at both dosages, caused a significant decrease of the levels of mdr1a, mdr1b, mrp1 and mrp2 in the livers of fetuses, and an increase in the levels of mdr1a, mdr1b, mrp2 and cyp3A2 in the mothers. In the other organs examined, a physiological regulation during ontogenesis was also evident, but SJW administration did not modify the expression level of the considered transcripts.These data suggest that the administration of the extract together with drugs that are substrates of transport proteins could be particularly hazardous during pregnancy. Copyright © 2006 John Wiley & Sons, Ltd.
Exposure and acceptance in the rehabilitation of adolescents with idiopathic chronic pain – A pilot study
Authors: Wicksell Rikard K. , Melin Lennart , Olsson Gunnar L. 
Published: April 2006

AbstractFor chronic pain of unclear origin (idiopathic), pharmacological therapy is often insufficient. Psychological treatment strategies have been developed and evaluated for adults with chronic pain. However, few such studies are seen with youths, and to date there is limited empirical evidence regarding the effectiveness of psychological treatment for generalized musculoskeletal pain syndromes in adolescents. Acceptance and commitment therapy (ACT) is a development of cognitive behaviour therapy emphasizing exposure and acceptance. In this pilot study, 14 adolescents referred to the pain treatment service due to chronic debilitating pain were treated using an ACT‐based approach. It was hypothesized that avoidance of pain and related stimuli was central to the disability seen among these patients, and that exposure and acceptance strategies could increase functioning and decrease pain. In contrast to emphasizing reductions in pain and distress, the treatment objective was to improve functioning by increasing the patient's ability to act in line with personal values in the presence of negative thoughts, emotions or bodily sensations. Following treatment, and retained at 3‐ and 6‐month follow‐up, improvements in functional ability, school attendance, catastrophizing and pain (i.e., intensity and interference) were seen. The outcome of this pilot study indicates that exposure and acceptance can been useful in the rehabilitation of adolescents with chronic debilitating pain. Randomized controlled studies are needed to empirically evaluate the effectiveness of this approach.
Climate and ocean variability during the middle and late Holocene recorded in laminated sediments from Alfonso Basin, Gulf of California, Mexico
Authors: Pérez-Cruz Ligia 
Published: April 2006

AbstractA laminated sequence (core BAP96-CP 24°38.12′N, 110°33.24′W; 390 m depth) from the Alfonso Basin in Bay of La Paz, southern Gulf of California, contains a record of paleoceanographic and paleoclimatic changes of the past 7900 yr. Radiolarian assemblages and magnetic susceptibility are used as proxies of oceanographic and climatic variability. The records provide a regional scenario of the middle and late Holocene, suggesting two major climatic regimes and several millennial-scale events. Conditions relatively warmer and drier than today occurred from ∼7700 to 2500 cal yr BP, promoting the intensification of evaporation processes and the prevalence of the Gulf of California water in the Basin. These conditions correlate with strong droughts in the middle Holocene of North America and with minimal incursion of tropical waters into the Gulf of California. Proxies indicate a warm scenario and the dominance of the Equatorial Surface Water in the Alfonso Basin from ∼2400 to 700 cal yr BP, suggesting the intensification of ENSO cycles. A climatic signal between ∼1038 and 963 cal yr BP may be correlated with global signal of the “Medieval Warm Period.” Several cooling events are recognized at 5730, 3360, 2700, 1280 and 820 cal yr BP and are associated with intensification of northwest winds leading to upwellings and enhanced productivity in the Basin.
NEST REPRESENTATIONS OF DIRECTED GRAPH ALGEBRAS
Authors: DAVIDSON KENNETH R. , KATSOULIS ELIAS 
Published: April 2006

This paper is a comprehensive study of the nest representations for the free semigroupoid algebra ${\mathfrak{L}}_G$ of a countable directed graph $G$ as well as its norm-closed counterpart, the tensor algebra ${\mathcal{T}}^{+}(G)$.We prove that the finite-dimensional nest representations separate the points in ${\mathfrak{L}}_G$, and a fortiori, in ${\mathcal{T}}^{+}(G)$. The irreducible finite-dimensional representations separate the points in ${\mathfrak{L}}_G$ if and only if $G$ is transitive in components (which is equivalent to being semisimple). Also the upper triangular nest representations separate points if and only if for every vertex $x \in {\mathcal{T}}(G)$ supporting a cycle, $x$ also supports at least one loop edge.We also study faithful nest representations. We prove that ${\mathfrak{L}}_G$ (or ${\mathcal{T}}^{+}(G)$) admits a faithful irreducible representation if and only if $G$ is strongly transitive as a directed graph. More generally, we obtain a condition on $G$ which is equivalent to the existence of a faithful nest representation. We also give a condition that determines the existence of a faithful nest representation for a maximal type ${\mathbb{N}}$ nest.
Conceptual Versus Monolingual Scoring
Authors: Bedore Lisa M. , Peña Elizabeth D. , García Melissa , Cortez Celina 
Published: April 2006

Purpose:This study evaluates the extent to which bilingual children produce the same or overlapping responses on tasks assessing semantic skills in each of their languages and whether classification analysis based on monolingual or conceptual scoring can accurately classify the semantic development of typically developing (TD) bilingual children.Method:In Study 1, 55 TD children (ages 4;0 [years;months] to 7;11) from bilingual backgrounds named characteristic properties of familiar items. The extent to which children produced overlapping responses in each of their languages and their errors were examined. In Study 2, 40 TD children (ages 5;0 to 6;1), group matched for age and bilingual language exposure, responded to the Phase 2 version of the Bilingual English Spanish Assessment (BESA; E. D. Peña, V. Gutierrez-Clellen, A. Iglesias, B. A. Goldstein, & L. M. Bedore, in development). Conceptual and monolingual scores were compared to determine the extent to which these were comparable for groups of children.Results:The results of Study 1 indicated that TD children from bilingual backgrounds are more likely to produce unique than overlapping responses when they respond to test items. Children were more likely to code switch when tested in Spanish than in English, but they were more likely to produce errors in English. In Study 2, monolingual and bilingual children achieved comparable conceptual scores. For Spanish-speaking bilingual children, the conceptual score was more likely to be in the average range of the monolingual children than was their monolingual score. For testing in English, monolingual and conceptual scores were similar.Clinical Implications:Bilingual children will benefit from conceptual scoring, especially when they are tested in Spanish.
Parental Recasts and Production of Copulas and Articles by Children With Specific Language Impairment and Typical Language
Authors: Proctor-Williams Kerry , Fey Marc E. , Loeb Diane Frome 
Published: April 2006

In intervention, children with specific language impairment (SLI) have been shown to develop productive use of morphemes in response to target-specific recasts at rates generally equivalent to younger, language-matched children with typical language development (TL). Our previous work demonstrated that in conversation, the overall recast rates produced by parents of children with SLI and those with TL are similar. Still, despite their apparently typical ability to use recast input in intervention and their equivalent environmental exposure to recasts, children with SLI continue to demonstrate grammatical delays in comparison to children with TL.
The purpose of this study was to examine three possible resolutions to this paradox. We examined target-specific copula and article recast usage by 10 parents of children with SLI and 10 parents of younger language-matched children with TL, and we examined their children’s productions of these same forms at three points across an 8-month period. The results provide strong support only for the third of the proposed hypotheses. Contrary to the predictions of the first hypothesis, a strong, positive relation was observed between the copula recasts used by parents of children with TL at Time 1 and their children’s use of copulas 8 months later. On the other hand, correlations between recasts of articles by parents and later production of articles by their children were not statistically reliable. Contrary to the second hypothesis, parents of children with SLI and those with TL produced equivalent rates of article and copula recasts. The third hypothesis received support on two essential counts. First, although significant correlations were found between parental recasts of copulas and production of this form 8 months later for the children with TL, no such relations were observed for the group with SLI. Second, the rate of parental target-specific recasts was less than a quarter of the rate provided in the successful intervention of Camarata, Nelson, and Camarata (1994). We conclude that children with SLI can benefit substantially from the grammar-facilitating properties of recasts, but only when the recasts are presented at rates that are much greater than those available in typical conversations with young children.
The Number of Individual Treatment Units Necessary to Facilitate Functional Communication Improvements in the Speech and Language of Young Children
Authors: Jacoby Gregory P. , Lee Linda , Kummer Ann W. , Levin Linda , Creaghead Nancy A. 
Published: April 2006

The present study was conducted to determine the average number of treatment units needed to achieve improvements in functional communication. The subjects, ages 3 to 6 years, consisted of 234 children who received speech-language pathology services over a two-year period at Children's Hospital Medical Center (CHMC) in Cincinnati, Ohio. Subjects had disorders of articulation and/or language and were rated on all areas of deficit using the ASHA functional communication measures (FCMs) of articulation/intelligibility, spoken language production, and spoken language comprehension. Because many subjects had more than one area of deficit, a total of 394 ratings were obtained.
Results indicated that as the number of treatment units increased, the FCM level improved. These improvements were statistically significant for subjects with articulation/intelligibility and spoken language production disorders only. Younger children received the greatest benefit per units of therapy provided. Children with lower initial functional abilities generally required more units of therapy to demonstrate improvement than children with higher initial ability levels. Children with an associated factor, (i.e., anoxic brain damage, syndromes, hearing loss, etc.) generally required more units of therapy than those who had no other factors, although the results were not statistically significant. The majority of subjects (76.5%) improved by at least one FCM level following 20 hours or more of therapy. There was improvement of two FCM levels in 38.5%, and more than two levels in 18.5% of the overall group. The present study indicates that improvement in FCM abilities is made with treatment, and that the degree of improvement is correlated with the number of treatment units provided.
Brain Correlates of Stuttering and Syllable Production
Authors: Ingham Roger J. , Fox Peter T. , Ingham Janis C. , Xiong Jinhu , Zamarripa Frank , Hardies L. Jean , Lancaster Jack L. 
Published: April 2006

This article reports a gender replication study of the P. T. Fox et al. (2000) performance correlation analysis of neural systems that distinguish between normal and stuttered speech in adult males. Positron-emission tomographic (PET) images of cerebral blood flow (CBF) were correlated with speech behavior scores obtained during PET imaging for 10 dextral female stuttering speakers and 10 dextral, age- and sex-matched normally fluent controls. Gender comparisons were made between the total number of voxels per region significantly correlated with speech performance (as in P. T. Fox et al., 2000) plus total voxels per region that were significantly correlated with stutter rate and not with syllable rate.
Stutter-rate regional correlates were generally right-sided in males, but bilateral in the females. For both sexes the positive regional correlates for stuttering were in right (R) anterior insula and the negative correlates were in R Brodmann area 21/22 and an area within left (L) inferior frontal gyrus. The female stuttering speakers displayed additional positive correlates in L anterior insula and in basal ganglia (L globus pallidus, R caudate), plus extensive right hemisphere negative correlates in the prefrontal area and the limbic and parietal lobes. The male stuttering speakers were distinguished by positive correlates in L medial occipital lobe and R medial cerebellum. Regions that positively correlated with syllable rate (essentially stutter-free speech) in stuttering speakers and controls were very similar for both sexes.
The findings strengthen claims that chronic developmental stuttering is functionally related to abnormal speech-motor and auditory region interactions. The gender differences may be related to differences between the genders with respect to susceptibility (males predominate) and recovery from chronic stuttering (females show higher recovery rates during childhood).