bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermodynamic Limitations of the Reptation Model
Authors: Fatkullin Nail , Kimmich Rainer 
Published: April 2006

AbstractSummary: The paper deals with the question whether the tube/reptation model of polymer chain dynamics is compatible with general laws of statistical physics. Based on a relation between the mean squared fluctuation of the number of segments in a given volume element and the isothermal compressibility of the polymer system, it follows straightforwardly that the tube/reptation model predicts fluctuations larger than permitted by thermodynamics on the time scale t ≳ τR, where τR is the Rouse relaxation time.
Molecular Dynamics Simulation of Dextran Extension at Constant Pulling Speed
Authors: Neelov Igor , Adolf David , Ratner Marina , Zhicol Oleg , McLeish Tom 
Published: April 2006

AbstractSummary: A dextran monomer and a 10mer under constant pulling speed were studied using the atomistic simulations. Molecular dynamics (MD) with the new Amber‐Glycam04 forcefield were performed. The main result of the present Amber‐based MD simulations is that the experimental plateau of the force‐extension dependence for dextran can be explained by a transition of the glucopyranose rings in the dextran monomers from a chair (4C1) to a inverted chair (1C4) conformation whereas chair to boat transitions occur at higher forces. Density functional (DFT) calculations of monomer were also performed for a monomer at different fixed end‐to‐end distances (lengths) to clarify the molecular mechanism of dextran extension. These DFT calculations confirm the existence of an inverted chair (1C4) conformation at intermediate extensions and its possible important contribution to the plateau in the experimental force‐extension dependence of dextran.
Improving kp Data Originating from PLP Number Distributions
Authors: Kornherr Andreas , Olaj Oskar Friedrich , Schnöll‐Bitai Irene , Zifferer Gerhard 
Published: April 2006

AbstractSummary: Based on certain features, especially the width of the so‐called extra peaks in the simulated number‐chain‐length distribution (CLD) of polymers prepared by pulsed laser polymerization (PLP), it is calculated by which factor the positions of the points of inflections and maxima deviate from the theoretical L0 data that are to be used for the evaluation of kp. These corrections are for slightly chain‐length‐dependent termination by disproportionation or combination and cover a wide range of chain‐lengths and primary radical production. They can be applied either to the point of inflection on the low‐molecular weight side of the extra peaks or to the peak maximum. On average, the mean error that is about −2.5% for uncorrected data from first‐order points of inflection is reduced to the order of less than 1% even if no assumption concerning the mode of termination is made. The situation is similar for the positions of the first‐order peak maxima where the mean error of about +7% likewise can be cut down to less than 1% if the proper correction function is chosen. Second‐ and third‐order peaks data, which are a priori less falsified, yield still better results after correction. Mass sensitivity of the detection process has comparatively little effect: it is only for unrealistically high extents of chain‐length dependence in detection that considerable falsifications are to be expected. As an additional result it turned out that correction functions obtained for number distributions are also applicable to mass spectrometry raw distributions $x(l) \cdot \sqrt l$ and even for mass distributions x(l) · l provided Poissonian broadening is the only broadening process.Number distribution xC(l) calculated for termination by combination times attenuation function F1(l).magnified imageNumber distribution xC(l) calculated for termination by combination times attenuation function F1(l).
Constant‐time solution to database searching by NMR ensemble computing
Authors: Hsueh C.‐C. , Chen C.‐Y. 
Published: April 2006

AbstractBrüschweiler's Ensemble algorithm requires n = log N queries to discover the wanted object from the database of the size N. In this paper, we use a new oracle query function g(.) to improve Brüschweiler's algorithm such that only one query is needed for searching the single object. Our algorithm extends from one ancillary qubit to n ancillary qubits. We then construct the oracle query function g(.) satisfying g(x) = 0 for all input x, except for one, say x = z, where g(z) = z. We first prepare 2n qubits, including n qubits for representing the elements and n ancillary qubits for storing the result of the oracle query function. After one query, we obtain z by measuring these ancillary qubits. Our algorithm can efficiently discover the wanted object if N ≤ 230 according to current NMR spectrometer technology.
All‐polymer microfluidic particle size sorter for biomedical applications
Authors: Fernandez Javier G. , Mills Christopher A. , Rodríguez Romen , Gomila Gabriel , Samitier Josep 
Published: April 2006

AbstractThe design and method for the production of an all‐polymer microfluidic particle sorter, for use in biomedical applications, is described. The sorter is made from biocompatible materials with properties, such as high optical transparency, that make it useful in a biological laboratory. The method of sorting is designed to be gentle on biological species, using a method of guiding the particles towards the filter, and has been successfully used to separate latex beads depending on their diameters. Preliminary qualitative experiments have been able to separate beads of 45 and 90 μm in diameter from a mixture of the two. These dimensions are on the same scale as those of some eukaryotic cells. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Uniaxial magnetic anisotropy of Fe–Si and Co–Si amorphous thin films due to Si nano‐segregation
Authors: Díaz J. , Valvidares S. M. , Morales R. , Alameda J. M. 
Published: April 2006

AbstractFe–Si and Co–Si amorphous thin films with Si concentrations above their eutectic point were deposited by magnetron sputtering. The films had a well defined uniaxial magnetic anisotropy induced by evaporating the Si atoms at an oblique angle of incidence. Their anisotropy energy and coercive field, measured by the transverse Kerr effect, increased with the temperature, suggesting that the distribution of Si concentration was not homogeneous giving rise to regions with different Curie temperatures. A model was proposed where the anisotropic distribution of Si would explain the origin of the uniaxial magnetic anisotropy in these films and the anomalous behaviour of their anisotropy energy and coercivity with the temperature. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
II–VI semiconductor quantum dot quantum wells: a tight‐binding study
Authors: Pérez‐Conde J. , Bhattacharjee A. K. 
Published: April 2006

AbstractWe have studied the electronic structure, exciton states and optical spectra of spherical semiconductor quantum dot quantum wells (QDQW's) by means of a symmetry‐adapted tight‐binding (TB) method. We have investigated two classes of QDQW's: CdS/HgS/CdS, based on a CdS core which acts as a barrier, with a thin HgS well layer intercalated between the core and a clad layer of CdS. The second class of QDQW's is based on ZnS cores covered with CdS layers which act in this case as a well. The calculated values of the absorption onset show a good agreement with the experimental data. Large photoluminescence Stokes shifts are also predicted. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical study of CO adsorption on Au/alumina substrates
Authors: Fernández E. M. , Balbás L. C. 
Published: April 2006

AbstractAiming to understand the role of the substrate in the adsorption of carbon monoxide on gold clusters supported on metal‐oxides, we have started a study of that process on two different alumina substrates: a fully relaxed stoichiometric (Al2O3)20 cluster, and the Al terminated (0001) surface of α‐Al2O3. Here we present first principles calculations for the adsorption of CO on a gold atom supported on these alumina substrates. The (Al2O3)20 cluster has atomic and electronic structures with similarities to those of amorphous alumina, and offers more different sites than the (0001) surface to bind gold clusters. In both cases, atomic Au adsorbs on top of a three coordinated Al atom with similar environment, being the binding energy higher in the case of the cluster substrate. CO absorbs preferentially on top of the Au atom, but in the case of cluster substrate, CO adsorbs also bridging Au and a neighbor O atom. This result suggest that the activity towards CO adsorption is larger for the Au/(amorphous‐cluster) than for Au/(0001)‐surface alumina substrate. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Soft Computing Techniques Applied to Combinatorial Catalysis: A New Approach for the Discovery and Optimization of Catalytic Materials
Authors: Serra Jose M. , Corma Avelino , Valero Soledad , Argente Estefania , Botti Vicente 
Published: April 2006

AbstractA soft computing technique based on the combination of Artificial Neural Networks (ANNs) and a Genetic Algorithm (GA) has been developed for the discovery and optimization of new materials when exploring a high‐dimensional space. This technique allows the experimental design in the search of new solid materials with high catalytic performance when exploring simultaneously a large number of variables such as elemental composition, manufacture procedure variables, etc. This novel integrated architecture allows one to strongly increase the convergence performance when compared with the performance of conventional GAs. It is described how both artificial intelligence techniques are built to work together. Moreover, the influence of algorithm configuration and the different algorithm parameters in the final optimization performance have been evaluated. The proposed optimization architecture has been validated using two hypothetical functions, based on the modeled behavior of multi‐component catalysts explored in the field of combinatorial catalysis.
Dye‐Modified and Photoswitchable Macrocycles by Multiple Multicomponent Macrocyclizations Including Bifunctional Building Blocks (MiBs)
Authors: Kreye Oliver , Westermann Bernhard , Rivera Daniel G. , Johnson Dean V. , Orru Romano V. A. , Wessjohann Ludger A. 
Published: April 2006

AbstractThe multiple multicomponent macrocyclization including bifunctional building blocks (MiB) strategy is suitable to obtain macrocycles with inherent dye or photoswitchable subunits. Provided as dicarboxylic components in Ugi‐MiBs, these functional subunits can be combined with natural like biarylether and peptoid moieties.
Allozymic variation in Northeast Atlantic and Mediterranean populations of Norway lobster, Nephrops norvegicus
Authors: Stamatis Costas , Triantafyllidis Alexander , Moutou Katerina A. , Mamuris Zissis 
Published: April 2006

AbstractAllozyme starch gel electrophoresis was used to investigate the genetic structure of Nephrops norvegicus populations in an extended sampling scheme. Nine populations from the North Sea and Aegean Sea were sampled and analysed using ten enzymatic systems corresponding to 15 putative loci. Values of heterozygosity were similar between Atlantic and Mediterranean population samples, ranging from 0.165 to 0.187. Genetic distance estimates, FST analyses and tests for genetic differentiation revealed a heterogeneous genetic structure within the sampling area of N. norvegicus. No evidence was found of past separation of Atlantic and Mediterranean populations, agreeing with the results of previous allozymic and mitochondrial genetic studies of N. norvegicus. Data are compared with genetic studies of other marine crustaceans and fish, and the implications for management of N. norvegicus stocks are discussed.
ASSOCIATION OF HOUSEHOLD DEMOGRAPHIC VARIABLES WITH CHILD MORTALITY IN CÔTE D’IVOIRE
Authors: ANDOH SAMUEL Y. , UMEZAKI MASAHIRO , NAKAMURA KEIKO , KIZUKI MASASHI , TAKANO TAKEHITO 
Published: April 2006

Summary.The associations between household demographic variables and mortality of children aged less than five years were investigated using data from the 1998 Demographic and Health Survey (DHS) of the Republic of Côte d’Ivoire, Western Africa. Of the total of 1992 children born to women included in the study population during the 5-year period preceding the survey, 260 (13%) had died and 1732 (87%) were alive at the time of the survey. Logistic regression analyses used to compare biosocial variables between the deceased and living children showed that the sex of the child, birth interval and mother’s occupation were associated with child’s survival status. After adjusting for their effects, household demographic variables (i.e. number of household members, number of household members under 5 years [HM−5Y], number of household members 5 years or older [HM+5Y], the proportion of HM−5Y among all household members, and the ratio of HM−5Y to HM+5Y) were shown to be associated with the child’s survival status. This study provided insight into the effects of intra-household competition among children and availability of care-givers as potential determinants of child survival. The results indicate that improvement of the childcare environment and reproductive intervention are necessary to reduce child mortality in West African countries.
From Ear to Cortex
Authors: Nittrouer Susan 
Published: April 2006

Phoneme-sized phonetic segments are often defined as the most basic unit of language organization. Two common inferences made from this description are that there are clear correlates to phonetic segments in the acoustic speech stream, and that humans have access to these segments from birth. In fact, well-replicated studies have shown that the acoustic signal of speech lacks invariant physical correlates to phonetic segments, and that the ability to recognize segmental structure is not present from the start of language learning. Instead, the young child must learn how to process the complex, generally continuous acoustic speech signal so that phonetic structure can be derived.This paper describes and reviews experiments that have revealed developmental changes in speech perception that accompany improvements in access to phonetic structure. In addition, this paper explains how these perceptual changes appear to be related to other aspects of language development, such as syntactic abilities and reading. Finally, evidence is provided that these critical developmental changes result from adequate language experience in naturalistic contexts, and accordingly suggests that intervention strategies for children with language learning problems should focus on enhancing language experience in natural contexts.
Psychoacoustic Performance in Children Completing Fast ForWord Training
Authors: Thibodeau Linda M. , Friel-Patti Sandy , Britt Lana 
Published: April 2006

It has been hypothesized that one cause of children's language disorders is poor temporal processing. When children are not able to follow the rapid modulations in the speech signal that cue phonemic information, development of critical language concepts might be missed. It has also been suggested that intensive auditory training on a hierarchy of temporal tasks may significantly improve language processing. Temporal processing was evaluated in children with normal language and those with language impairment who were enrolled in an intensive computerized auditory training program. The psychoacoustic tasks were aimed at evaluating the ability to (1) process signals arriving in very close succession, and (2) discriminate signals changing rapidly in frequency.
Three dependent variables included thresholds for brief tones presented in three conditions: quiet, just before a masker, and simultaneously with a masker. A fourth dependent variable was the minimum detectable change in a tone sweeping up in frequency. Despite minimal changes in performance over the five-week period, there were overlaps in performance on all tasks between the groups suggesting a complex relationship between temporal processing and language development. Children with language impairment who had better performance on the masking and frequency discrimination tasks showed greater success on the auditory training program.
The Effects of Changes in Hearing Status in Cochlear Implant Users on the Acoustic Vowel Space and CV Coarticulation
Authors: Lane Harlan , Matthies Melanie , Perkell Joseph , Vick Jennell , Zandipour Majid 
Published: April 2006

In order to examine the role of hearing status in controlling coarticulation, eight English vowels in /bVt/ and /dVt/ syllables, embedded in a carrier phrase, were elicited from 7 postlingually deafened adults and 2 speakers with normal hearing. The deaf adults served in repeated recording sessions both before and up to a year after they received cochlear implants and their speech processors were turned on. Each of the two hearing control speakers served in two recording sessions, separated by about 3 months. Measures were made of second formant frequency at obstruent release and at 25 ms intervals until the final obstruent.
An index of coarticulation, based on the ratio of F2 at vowel onset to F2 at midvowel target, was computed. Changes in the amount of coarticulation after the change in hearing status were small and nonsystematic for the /bVt/ syllables; those for the /dVt/ syllables averaged a 3% increase—within the range of reliability measures for the 2 hearing control speakers. Locus equations (F2 at vowel onset vs. F2 at vowel midpoint) and ratios of F2 onsets in point vowels were also calculated. Like the index of coarticulation, these measures tended to confirm that hearing status had little if any effect on coarticulation in the deaf speakers, consistent with the hypothesis that hearing does not play a direct role in regulating anticipatory coarticulation in adulthood.
With the restoration of some hearing, 2 implant users significantly increased the average spacing between vowels in the formant plane, whereas the remaining 5 decreased that measure. All speakers but one also reduced vowel duration significantly. Four of the speakers reduced dispersion of vowel formant values around vowel midpoint means, but the other 3 did not show this effect.
A Prosodically Controlled Word and Nonword Repetition Task for 2- to 4-Year-Olds
Authors: Roy Penny , Chiat Shula 
Published: April 2006

An association has been found between nonword repetition and language skills in school-age children with both typical and atypical language development (C. Dollaghan & T. F. Campbell, 1998; S. Ellis Weismer et al., 2000; S. E. Gathercole & A. D. Baddeley, 1990; J. W. Montgomery, 2002). This raises the possibility that younger children's repetition performance may be predictive of later language deficits. In order to investigate this possibility, it is important to establish that elicited repetition with very young children is both feasible and informative. To this end, a repetition task was designed and carried out with 66 children between 2 and 4 years of age. The task consisted of 18 words and 18 matched nonwords that were systematically manipulated for length and prosodic structure. In addition, an assessment of receptive vocabulary was administered.
The repetition task elicited high levels of response. Total scores as well as word and nonword scores were sensitive to age. Lexical status and item length affected performance regardless of age: Words were repeated more accurately than nonwords, and 1-syllable items were repeated more accurately than 2-syllable items, which were in turn repeated more accurately than 3-syllable items. The effect of prosodic structure was also significant. Whole syllable errors were almost exclusive to unstressed syllables, with those preceding stress being most vulnerable. Performance on the repetition task was significantly correlated with performance on the receptive vocabulary test. This repetition task effectively elicited responses from most of the 2- to 4-year-old participants, tapped developmental change in their repetition skills, and revealed patterns in their performance; and thus it has the potential to identify deficits in very early repetition skills that may be indicative of wider language difficulties.
Clinical and Epidemiologic Features of Methicillin-Resistant Staphylococcus aureus in Elderly Hospitalized Patients
Authors: Simor Andrew E. , Ofner-Agostini Marianna , Paton Shirley , McGeer Allison , Loeb Mark , Bryce Elizabeth , Mulvey Michael 
Published: April 2006

AbstractWe describe characteristics of elderly patients with MRSA identified in 37 Canadian hospitals between 1995 and 2002. Of these inpatients, 6,613 (66%) were older than 65 years. They were more likely than younger patients to have been colonized without infection and to have had MRSA isolated from urine or the perineum. The epidemiology and clinical features of these patients is distinct from that of younger patients.
Where is T5? A survey of anaesthetists*
Authors: Congreve K. , Gardner I. , Laxton C. , Scrutton M. 
Published: April 2006

SummaryThe extent of a regional block for Caesarean section must be tested and documented before surgery commences. In recent years a block to ‘touch’ that includes T5 has increasingly been considered the best predictive test for a pain‐free Caesarean section. Our survey examines the consistency with which different anaesthetists identified the location of the T5 dermatome. Seventy‐three anaesthetists were asked to mark a point on an anatomical picture to indicate where they would test for T5. Overall there was good agreement on the location of the T5 dermatome, but one in seven anaesthetists were inaccurate by two or more dermatomes. There were no statistically significant differences between the subgroups of senior house officer, specialist registrar and consultant anaesthetists. The knowledge of relevant dermatome levels should be an integral part of obstetric anaesthetic training.
The effects of the exaggerated lithotomy position for radical perineal prostatectomy on respiratory mechanics
Authors: Choi S. J. , Gwak M. S. , Ko J. S. , Lee H. , Yang M. , Lee S. M. , Kim G. S. , Kim M. H. 
Published: April 2006

SummaryThe exaggerated lithotomy position is used during radical perineal prostatectomy to increase perineal exposure. The aim of this study was to evaluate the effects of the exaggerated lithotomy position on respiratory mechanics and arterial blood gases. In the exaggerated lithotomy position, dynamic compliance and static compliance were found to be significantly decreased by 27.4% and 34.8%, respectively, whilst peak, plateau, and mean airway pressures increased significantly by 34.0%, 45.8% and 31.7%, respectively. The physiological dead space/tidal volume ratio and total inspiratory work of breathing increased significantly by 11.1% and 33.7%, respectively. Arterial oxygen tension was significantly decreased by 26.9%; however, no significant differences were seen in end‐tidal or arterial carbon dioxide tension. These results indicate that the exaggerated lithotomy position under general anaesthesia can cause significant effects on respiratory system mechanics and arterial oxygenation and highlights the need for careful monitoring of patients placed in this position for surgery.