bluuebunny/crossref_metadata_2025_split huggingface dataset:
Localization of high-frequency waves propagating in a locally periodic medium
Authors: Allaire G. , Friz L. 
Published: October 2010

AbstractWe study the homogenization and localization of high-frequency waves in a locally periodic media with period ε. We consider initial data that are localized Bloch-wave packets, i.e. that are the product of a fast oscillating Bloch wave at a given frequency ξ and of a smooth envelope function whose support is concentrated at a point x with length scale $\sqrt\varepsilon$. We assume that (ξ, x) is a stationary point in the phase space of the Hamiltonian λ(ξ, x), i.e. of the corresponding Bloch eigenvalue. Upon rescaling at size $\sqrt\varepsilon$ we prove that the solution of the wave equation is approximately the sum of two terms with opposite phases which are the product of the oscillating Bloch wave and of two limit envelope functions which are the solution of two Schrödinger type equations with quadratic potential. Furthermore, if the full Hessian of the Hamiltonian λ(ξ, x) is positive definite, then localization takes place in the sense that the spectrum of each homogenized Schrödinger equation is made of a countable sequence of finite multiplicity eigenvalues with exponentially decaying eigenfunctions.
A non-autonomous competitive system with stage structure and distributed delays
Authors: Wang Jiaoyan , Feng Zhaosheng 
Published: October 2010

AbstractWe consider a non-autonomous competitive model with generalized functional responses for interaction among n species, the adult members of which are in competition. For each of the n species the model incorporates a distributed time delay which represents the time from birth to maturity of that species. Based on some comparison arguments, we discuss the permanence and extinction of the species. By virtue of the continuation theorem of coincidence degree theory, we prove the existence of a positive periodic solution. By means of constructing appropriate Lyapunov functionals, we obtain sufficient conditions for the uniqueness and the global stability of the periodic solution. Two examples are given to illustrate the feasibility of our main results.
Dynamics of a non-local delayed reaction–diffusion equation without quasi-monotonicity
Authors: Wang Zhi-Cheng , Li Wan-Tong 
Published: October 2010

AbstractThis paper is concerned with the dynamics of a non-local delayed reaction–diffusion equation without quasi-monotonicity on an infinite n-dimensional domain, which can be derived from the growth of a stage-structured single-species population. We first prove that solutions of the Cauchy-type problem are positively preserving and bounded if the initial value is non-negative and bounded. Then, by establishing a comparison theorem and a series of comparison arguments, we prove the global attractivity of the positive equilibrium. When there exist no positive equilibria, we prove that the zero equilibrium is globally attractive. In particular, these results are still valid for the non-local delayed reaction–diffusion equation on a bounded domain with the Neumann boundary condition. Finally, we establish the existence of new entire solutions by using the travelling-wave solutions of two auxiliary equations and the global attractivity of the positive equilibrium.
Moment bounds for the solutions of the Smoluchowski equation with coagulation and fragmentation
Authors: Rezakhanlou Fraydoun 
Published: October 2010

AbstractWe prove various $L^p(\mathbb{R}^d\times[0,T])$ bounds on momentswhere fm is a solution of the discrete (respectively, continuous) Smoluchowski coagulation–fragmentation equations with diffusion. In a previous paper we proved similar results for all weak solutions to the discrete Smoluchowski equation provided that there is no fragmentation and certain moments are bounded in suitable Lq-spaces initially. We prove the corresponding results in the case of the continuous Smoluchowski equation. When there is also fragmentation, we need to assume that the solution f is regular in the sense that f can be approximated by solutions to the Smoluchowski equation for which the coagulation and fragmentation coefficients are 0 when the cluster sizes are large. We also need suitable assumptions on the coagulation rates to avoid gelation. On the fragmentation rate β we assume that supn supm≤l β(m, n)/n < ∞ for every positive l, and that there exist constants a0 ≥ 0 and c0 such that β(n,m) ≤ c0(n + m)a0a0.
Social competence, externalizing, and internalizing behavioral adjustment from early childhood through early adolescence: Developmental cascades
Authors: Bornstein Marc H. , Hahn Chun-Shin , Haynes O. Maurice 
Published: October 2010

AbstractThis study used a three-wave longitudinal design to investigate developmental cascades among social competence and externalizing and internalizing behavioral adjustment in a normative sample of 117 children seen at 4, 10, and 14 years. Children, mothers, and teachers provided data. A series of nested path analysis models was used to determine the most parsimonious and plausible cascades across the three constructs over and above their covariation at each age and stability across age. Children with lower social competence at age 4 years exhibited more externalizing and internalizing behaviors at age 10 years and more externalizing behaviors at age 14 years. Children with lower social competence at age 4 years also exhibited more internalizing behaviors at age 10 years and more internalizing behaviors at age 14 years. Children who exhibited more internalizing behaviors at age 4 years exhibited more internalizing behaviors at age 10 years and more externalizing behaviors at age 14 years. These cascades among social competence and behavioral adjustment obtained independent of child intelligence and maternal education and social desirability of responding.
From child maltreatment to adolescent cannabis abuse and dependence: A developmental cascade model
Authors: Rogosch Fred A. , Oshri Assaf , Cicchetti Dante 
Published: October 2010

AbstractA developmental cascade model tested associations among child maltreatment, internalizing and externalizing psychopathology, social competence, and cannabis abuse and dependence symptoms in a longitudinal cohort (N= 415). Nested structural equation models evaluated continuity and cross-domain influences among broad multi-informant constructs across four developmental periods: age 7 to 9, 10 to 12, 13 to 15, and 15 to 18. Results indicated significant paths from child maltreatment to early externalizing and internalizing problems and social competence, as well as to cannabis abuse and dependence (CAD) symptoms in adolescence. Youth CAD symptoms were primarily related directly to child maltreatment and externalizing problems. Childhood internalizing symptoms contributed to later childhood decreases in social competence, which predicted increases in late adolescent externalizing problems. Using a developmental psychopathology framework, results are discussed in relation to cascade and transactional effects and the interplay between problem behaviors during childhood and development of CAD symptoms during early and late adolescence.
Substance use changes and social role transitions: Proximal developmental effects on ongoing trajectories from late adolescence through early adulthood
Authors: Staff Jeremy , Schulenberg John E. , Maslowsky Julie , Bachman Jerald G. , O'Malley Patrick M. , Maggs Jennifer L. , Johnston Lloyd D. 
Published: October 2010

AbstractSubstance use changes rapidly during late adolescence and early adulthood. This time in the life course is also dense with social role changes, as role changes provide dynamic context for individual developmental change. Using nationally representative, multiwave longitudinal data from age 18 to 28, we examine proximal links between changes in social roles and changes in substance use during the transition to adulthood. We find that changes in family roles, such as marriage, divorce, and parenthood, have clear and consistent associations with changes in substance use. With some notable exceptions, changes in school and work roles have weaker effects on changes in substance use compared to family roles. Changes in socializing (i.e., nights out for fun and recreation) and in religiosity were found to mediate the relationship of social role transitions to substance use. Two time-invariant covariates, socioeconomic background and heavy adolescent substance use, predicted social role status, but did not moderate associations, as within-person links between social roles and substance use were largely equivalent across groups. This paper adds to the cascading effects literature by considering how, within individuals, more proximal variations in school, work, and family roles relate to variations in substance use, and which roles appear to be most influential in precipitating changes in substance use during the transition to adulthood.
Testing a developmental cascade model of adolescent substance use trajectories and young adult adjustment
Authors: Lynne-Landsman Sarah D. , Bradshaw Catherine P. , Ialongo Nicholas S. 
Published: October 2010

AbstractDevelopmental models highlight the impact of early risk factors on both the onset and growth of substance use, yet few studies have systematically examined the indirect effects of risk factors across several domains, and at multiple developmental time points, on trajectories of substance use and adult adjustment outcomes (e.g., educational attainment, mental health problems, criminal behavior). The current study used data from a community epidemiologically defined sample of 678 urban, primarily African American youth, followed from first grade through young adulthood (age 21) to test a developmental cascade model of substance use and young adult adjustment outcomes. Drawing upon transactional developmental theories and using growth mixture modeling procedures, we found evidence for a developmental progression from behavioral risk to adjustment problems in the peer context, culminating in a high-risk trajectory of alcohol, cigarette, and marijuana use during adolescence. Substance use trajectory membership was associated with adjustment in adulthood. These findings highlight the developmental significance of early individual and interpersonal risk factors on subsequent risk for substance use and, in turn, young adult adjustment outcomes.
Parents’ experiences of having an asymptomatic child diagnosed with hypertrophic cardiomyopathy through family screening
Authors: Bratt Ewa-Lena , Östman-Smith Ingegerd , Sparud-Lundin Carina , Axelsson B. Åsa 
Published: October 2010

AbstractBackgroundHypertrophic cardiomyopathy is hereditary and the commonest medical cause of sudden death in childhood and adolescence, which is the reason for recommending screening in children with an affected parent. A diagnosis of hypertrophic cardiomyopathy implies lifestyle modifications, restrictions that may bring profound changes to the affected individual and impacts on the whole family.ObjectiveTo describe parents’ experiences of how the diagnosis of hypertrophic cardiomyopathy in their child affects daily life.MethodTwelve parents with asymptomatic children diagnosed with hypertrophic cardiomyopathy through family screening were interviewed 12–24 months after the diagnosis. Analysis was conducted with qualitative content analysis.ResultsParents described the immediate reaction of shock, grief, and injustice but were also grateful that the child was still asymptomatic. The diagnosis caused a significant change in lifestyle for most families due mainly to restrictions of sports activities. Parents had to adapt to the new life and develop strategies to protect their child. Death became a reality causing feelings of vulnerability. Regular medical check-ups and access to the liaison nurse were described as important factors of reassurance.ConclusionsParents experienced early diagnosis as positive in a long-term perspective. The main changes perceived were ascribed to lifestyle modifications. Parents with athletic children experienced the lifestyle modifications as more severe. They strived to create a new life where they could feel secure and have faith in the future, and emphasised the need of regular follow-up and support from health care professionals as “mental pain relief”, which helped them achieve a new state of normality.
On the Field Evaporation Behavior of Dielectric Materials in Three-Dimensional Atom Probe: A Numeric Simulation
Authors: Oberdorfer Christian , Schmitz Guido 
Published: October 2010

AbstractAs a major improvement in three-dimensional (3D) atom probe, the range of applicable material classes has recently been broadened by the establishment of laser-assisted atom probes (LA-3DAP). Meanwhile, measurements of materials of low conductivity, such as dielectrics, ceramics, and semiconductors, have widely been demonstrated. However, besides different evaporation probabilities, heterogeneous dielectric properties are expected to give rise to additional artifacts in the 3D volume reconstruction on which the method is based. In this article, these conceivable artifacts are discussed based on a numeric simulation of the field evaporation. Sample tips of layer- or precipitate-type geometry are considered. It is demonstrated that dielectric materials tend to behave similarly to metals of reduced critical evaporation field.
An Acoustic Study of the Relationships Among Neurologic Disease, Dysarthria Type, and Severity of Dysarthria
Authors: Kim Yunjung , Kent Raymond D. , Weismer Gary 
Published: October 2010

Purpose
This study examined acoustic predictors of speech intelligibility in speakers with several types of dysarthria secondary to different diseases and conducted classification analysis solely by acoustic measures according to 3 variables (disease, speech severity, and dysarthria type).

Method
Speech recordings from 107 speakers with dysarthria due to Parkinson’s disease, stroke, traumatic brain injury, and multiple system atrophy were used for acoustic analysis and for perceptual judgment of speech intelligibility. Acoustic analysis included 8 segmental/suprasegmental features: 2nd formant frequency slope, articulation rate, voiceless interval duration, 1st moment analysis for fricatives, vowel space, F0, intensity range, and Pairwise Variability Index.

Results
The results showed that (a) acoustic predictors of speech intelligibility differed slightly across diseases and (b) classification accuracy by dysarthria type was typically worse than by disease type or severity.

Conclusions
These findings were discussed with respect to (a) the relationship between acoustic characteristics and speech intelligibility and (b) dysarthria classification.
Preparation of Late Drosophila Embryonic Fillets
Authors: Ramachandran Preethi , Budnik Vivian 
Published: October 2010

INTRODUCTIONBeyond the age of ~15 h (at 25°C), Drosophila embryos become impenetrable to aqueous fixatives and staining methods as a result of cuticle deposition. This problem can be overcome using flat or fillet preparations, as described in this protocol.
Preparation of Microsphere Tips for Atomic Force Microscopy (AFM): Figure 1.
Authors: Plodinec Marija , Loparic Marko , Aebi Ueli 
Published: October 2010

INTRODUCTIONThis protocol describes the preparation and use of spherical indenters for micrometer-scale imaging and mechanical testing with atomic force microscopy (AFM). A spherical indenter is prepared by gluing a hard borosilicate sphere to a tipless cantilever. For this purpose, a stereomicroscope with a micromanipulator attachment is employed. The spheres are cleaned prior to gluing to remove any contamination from their surfaces. Once they are cleaned, the borosilicate spheres are stored in absolute ethanol in a glass tube.
Detection of Cytosine Methylation in RNA Using Bisulfite Sequencing
Authors: Pollex Tim , Hanna Katharina , Schaefer Matthias 
Published: October 2010

INTRODUCTIONPost-transcriptional RNA modifications are a characteristic feature of noncoding RNAs and have been described for ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), and various other small RNAs. However, the biological function of most of these modifications remains uncharacterized. Cytosine-5 methylation (5mC) has been detected in abundant and long-lived RNA molecules such as rRNAs and tRNAs, but, because of technical limitations, the occurrence of base-methylated cytosines in other RNAs is not known. To facilitate the detection of RNA methylation, we have established a method for analyzing base-methylated cytosines in RNA using bisulfite sequencing. Treatment of RNA with bisulfite causes the chemical deamination of nonmethylated cytosines to uracil, while methylated cytosines remain unaffected. cDNA synthesis followed by polymerase chain reaction (PCR) amplification and DNA sequencing allows investigators to reproducibly and quantitatively distinguish unmethylated cytosines (as thymines) from methylated cytosines in tRNAs and rRNAs. Using high-throughput sequencing approaches, this protocol should enable the characterization of 5mC methylation patterns in any RNA molecule, including low abundance RNAs.
Functional Analysis of Genes in Aedes aegypti Embryos
Authors: Clemons Anthony , Haugen Morgan , Severson David , Duman-Scheel Molly 
Published: October 2010

INTRODUCTIONBlood-feeding mosquitoes, including the dengue and yellow fever vector Aedes aegypti, transmit many of the world’s deadliest diseases. Such diseases have resurged in developing countries and pose clear threats for epidemic outbreaks in developed countries. Recent mosquito genome projects have stimulated interest in the potential for arthropod-borne disease control by genetic manipulation of vector insects, and genes that regulate development are of particular interest. In recent years, RNA interference (RNAi) has proven to be an effective strategy for inhibiting gene function in many organisms. This protocol describes a method for knockdown of embryonic genes in Ae. aegypti embryos by microinjection of small interfering RNA (siRNA) designed to target a specific gene of interest. The procedure includes a strategy for siRNA design, microinjection, and measurement of knockdown effectiveness.
The exo‐ or endonucleolytic preference of bovine pancreatic ribonuclease A depends on its subsites structure and on the substrate size
Authors: Cuchillo Claudi M. , Moussaoui Mohamed , Barman Tom , Travers Franck , Nogués M. Victòria 
Published: October 2010

AbstractThe cleavage pattern of oligocytidylic acid substrates by bovine pancreatic ribonuclease A (RNase A) was studied by means of reversed‐phase HPLC. Oligocytidylic acids, ranging from dinucleotides to heptanucleotides, were obtained by RNase A digestion of poly(C). They were identified by MALDI‐TOF mass spectrometry; it was confirmed that all of them corresponded to the general structure (Cp)nC>p, in which C>p indicates a 2′,3′‐cyclic phosphate. This is a confirmation of the proposed mechanism for RNase A, wherein the so‐called hydrolytic (or second) step is in fact a special case of the reverse of transphosphorylation (first step). The patterns of cleavage for the oligonucleotide substrates show that the native enzyme has no special preference for endonucleolytic or exonucleolytic cleavage, whereas a mutant of the enzyme (K7Q/R10Q‐RNase A) lacking p2 (a phosphate binding subsite adjacent, on the 3′ side, to the main phosphate binding site p1) shows a clear exonucleolytic pattern; a mutant (K66Q‐RNase A) lacking p0 (a phosphate binding subsite adjacent, on the 5′ side, to the main phosphate binding site p1) shows a more endonucleolytic pattern. This indicates the important role played by the subsites on the preference for the bond cleaved. Molecular modeling shows that, in the case of the p2 mutant, the amide group of glutamine can form a hydrogen bond with the 2′,3′‐cyclic terminal phosphate, whereas the distance to a 3′,5′‐phosphodiester bond is too long to form such a hydrogen bond. This could explain the preference for exonucleolytic cleavage shown by the p2 mutant.
15N nuclear magnetic resonance relaxation studies on rat β‐parvalbumin and the pentacarboxylate variants, S55D and G98D
Authors: Henzl Michael T. , Wycoff Wei G. , Larson John D. , Likos John J. 
Published: October 2010

Abstract15N relaxation data for Ca2+‐bound rat β‐parvalbumin (a.k.a. oncomodulin) were analyzed using the Lipari‐Szabo formalism and compared with existing data for rat α‐parvalbumin. Although the averageS2values for the two proteins are very similar (0.85 for α, 0.84 for β), residue‐by‐residue inspection reveals systematic differences. α tends to have the lowerS2value in helical regions; β tends to have the lower value in the loop regions. Rat β was also examined in the Ca2+‐free state. The 59 assigned residues displayed an average order parameter (0.90) significantly greater than the corresponding residues in the Ca2+‐loaded form. The pentacarboxylate variants of rat β—S55D and G98D—also were examined in the Ca2+‐bound state. Although both mutations significantly heighten Ca2+affinity, they utilize distinct energetic strategies. S55D improves the Ca2+‐binding enthalpy; G98D improves the binding entropy. They also show disparate peptide backbone dynamics. Whereas β G98D displays an average order parameter (0.87) slightly greater than that of the wild‐type protein, β S55D displays an average order parameter (0.82) slightly lower than wild‐type β. Furthermore, whereas just two backbone N‐H bonds in β G98D show internal motion on the 20–200‐psec timescale, fully 52 of the 93 residues analyzed in β S55D show this behavior. These findings suggest that the increased electrostatic repulsion attendant to introduction of an additional carboxylate into the CD site ligand array impedes backbone vibrational motion throughout the molecule.
Structure‐based prediction of modifications in glutarylamidase to allow single‐step enzymatic production of 7‐aminocephalosporanic acid from cephalosporin C
Authors: Fritz‐Wolf Karin , Koller Klaus‐Peter , Lange Gudrun , Liesum Alexander , Sauber Klaus , Schreuder Herman , Aretz Werner , Kabsch Wolfgang 
Published: October 2010

AbstractGlutarylamidase is an important enzyme employed in the commercial production of 7‐aminocephalosporanic acid, a starting compound in the synthesis of cephalosporin antibiotics. 7‐aminocephalosporanic acid is obtained from cephalosporin C, a natural antibiotic, either chemically or by a two‐step enzymatic process utilizing the enzymes D‐amino acid oxidase and glutarylamidase. We have investigated possibilities for redesigning glutarylamidase for the production of 7‐aminocephalosporanic acid from cephalosporin C in a single enzymatic step. These studies are based on the structures of glutarylamidase, which we have solved with bound phosphate and ethylene glycol to 2.5 Å resolution and with bound glycerol to 2.4 Å. The phosphate binds near the catalytic serine in a way that mimics the hemiacetal that develops during catalysis, while the glycerol occupies the side‐chain binding pocket. Our structures show that the enzyme is not only structurally similar to penicillin G acylase but also employs essentially the same mechanism in which the α‐amino group of the catalytic serine acts as a base. A subtle difference is the presence of two catalytic dyads, His B23/Glu B455 and His B23/Ser B1, that are not seen in penicillin G acylase. In contrast to classical serine proteases, the central histidine of these dyads interacts indirectly with the Oγ through a hydrogen bond relay network involving the α‐amino group of the serine and a bound water molecule. A plausible model of the enzyme–substrate complex is proposed that leads to the prediction of mutants of glutarylamidase that should enable the enzyme to deacylate cephalosporin C into 7‐aminocephalosporanic acid.