bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scalar mixing by granular particles
Authors: Derksen J. J. 
Published: May 2008

AbstractWe study by direct numerical simulation the role of spherical, solid, uniformly sized, moving particles immersed in a fluid in spreading a passive scalar with high Schmidt number dissolved in the fluid. The solid particles are one‐way coupled to the fluid: they agitate the fluid but they do not feel the presence of the fluid (they move as a granular gas). The two independent variables in the simulations are the solids volume fraction that we vary in the range of 10–45%, and the granular Reynolds number, based on the particle diameter and the granular temperature, which has been varied from 2.8 to 280. It is shown that the scalar spreading rate strongly decreases with increasing solids volume fraction; the spreading appears to scale quite well with the mean free path of the particles. At increasing granular Reynolds number the fluid flow develops more small scale structures that enhance scalar spreading. We propose a relation for an effective diffusion coefficient that describes the scalar spreading in terms of the independent variables. © 2008 American Institute of Chemical Engineers AIChE J, 2008
Recurrent non‐immune hydrops fetalis with gracile bones and dysmorphic features in siblings
Authors: Abboy Sri , Weaver David D. , Padilla Lillie‐Mae , Faught Philip , Akin Kelly K 
Published: May 2008

AbstractWe report on two siblings with recurrent non‐immune hydrops fetalis of unknown etiology. The proposita was born at 32‐week gestation with hydrops fetalis. She died at less than 1 hr of age despite resuscitative efforts. Her brother was born $1{\raise0.5ex\hbox{$\scriptstyle 1$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}$ years later to the same parents. He was also born at 32‐week gestation and lived 40 min. At birth, both individuals were noted to have marked edema of the entire body, slightly low set ears, small nose, mild micrognathia, small chest, camptodactyly, single transverse palmar creases, rhizomelic shortening of the upper extremities, slight ankle varus deformity bilaterally and bilateral humeral fractures. Postnatal chromosomal analysis of the first patient was normal. In both cases, evaluation for lysosomal storage disorders utilizing skin fibroblasts was negative. The radiographs and autopsies were done on both patients and showed diffuse soft‐tissue edema, gracile bones, especially in the upper extremities and ribs, and bilateral humeral fractures in both children. Both patients had absence of germ cells. The skeletal system in both appeared otherwise normal. After testing for infectious, chromosomal, hematological, hepatic and metabolic causes, we were unable to identify the etiology of the condition in the above patients. Further, we have been unable to identify a reported genetic condition with the features present in these cases. As such, we believe that the disorder in the individuals reported here represent a new autosomal recessive condition. © 2008 Wiley‐Liss, Inc.
Reduced telomere length in older men with premutation alleles of the fragile X mental retardation 1 gene
Authors: Jenkins Edmund C. , Tassone Flora , Ye Lingling , Gu Hong , Xi Man , Velinov Milen , Brown W. Ted , Hagerman Randi J. , Hagerman Paul J. 
Published: May 2008

AbstractReduced telomere length has recently been reported in T lymphocytes of individuals with trisomy 21 Down syndrome (DS) and dementia. Shorter telomeres also have been documented in dyskeratosis congenita, cell senescence, Alzheimer disease, and neoplastic transformation. These observations suggest that similar shortening may occur in people with fragile X‐associated tremor/ataxia syndrome (FXTAS), which frequently is accompanied by dementia. To test this hypothesis, telomere length has been quantified in T lymphocytes from older male carriers of premutation FMR1 alleles, with or without FXTAS, and FXTAS with dementia. Shorter telomeres (relative to age‐matched controls) were observed in 5/5 individuals with FXTAS and dementia, in 2/2 individuals with FXTAS without dementia, and in 3/3 individuals with the fragile X premutation only (P values ranged from <0.001 to <0.05; Student's t‐test), indicating that telomere shortening is associated with the premutation expansion of the FMR1 gene. The current study design allowed simultaneous comparisons among control, premutation, FXTAS, and FXTAS with dementia samples, and showed nearly equal degrees of shortening relative to controls among the three premutation sample groups. Thus, telomere shortening may serve as a biomarker for cellular dysregulation that may precede the development of the symptoms of FXTAS. © 2008 Wiley‐Liss, Inc.
The art of coping with a craniofacial difference: Helping others through “Positive Exposure”
Authors: Loewenstein Johanna , Sutton Erica , Guidotti Rick , Shapiro Kristin , Ball Karen , McLean Diane , Biesecker Barbara 
Published: May 2008

AbstractFinding ways to cope with social stigmatization is an important aspect of achieving adaptation for people living with visible genetic differences. This study describes the way individuals with craniofacial differences use an innovative photography and video experience with Positive Exposure (PE), a non‐profit organization based in New York City, as a way to cope with their conditions. Thirty‐five individuals between 12 and 61 years of age participated in this study. We administered surveys comprised of open‐ended qualitative questions and quantitative measures designed to assess self‐esteem, perceived stigma, and hopefulness. Data for this analysis was generated from the written questionnaires and interview transcripts. Most participants reported high levels of self‐esteem and hopefulness, suggesting that they were relatively well adapted to their condition. Almost all participants described experiences of stigmatization throughout their lives. However, participants demonstrated their ability to implement a variety of coping strategies to manage stigma. “Helping others” emerged as a prominent strategy among participants, aiding in the often lifelong process of adapting to their genetic difference. PE was described as an avenue through which participants could reach out to individuals and society at large, helping them adapt further to their condition. “Helping others” may also benefit individuals with craniofacial differences who do not consider themselves to be well adapted to their condition. Health care providers can collaborate with PE, advocacy groups and other community or support groups to identify additional ways individuals with craniofacial differences can help themselves by reaching out to others. Published 2008 Wiley‐Liss, Inc.
Shwachman–Diamond syndrome is associated with structural brain alterations on MRI
Authors: Toiviainen‐Salo Sanna , Mäkitie Outi , Mannerkoski Minna , Hämäläinen Janne , Valanne Leena , Autti Taina 
Published: May 2008

AbstractShwachman–Diamond syndrome (SDS) is an autosomal recessive condition that results from mutations in theSBDSgene, at chromosome 7q11. Main features include exocrine pancreatic failure, neutropenia and skeletal dysplasia. This study investigated brain structures by magnetic resonance imaging (MRI) in patients with SDS. MRI of the brain was performed in nine patients (7 males, age range 7–37 years) with SDS and mutations in theSBDSgene and in 18 age‐ and gender‐matched controls. MRI images were assessed visually, and volumetric analyses of the brain matter and structural midsagittal measurements were performed. Eight out of nineSBDSmutation‐verified patients reported learning difficulties. Patients with SDS had smaller occipitofrontal head circumferences than the controls (Z‐score −1.3 vs. +0.3,P = 0.021), and decreased global brain volume (1.74 L vs. 1.94 L,P = 0.019); both gray matter (P = 0.042) and white matter (P = 0.007) volumes were reduced. Patients with SDS had no macroscopic brain malformations, but they had significantly smaller age‐ and head size‐adjusted areas of posterior fossa (P = 0.006), vermis (P = 0.002), corpus callosum (P = 0.020), and pons (P = 0.002), and significantly larger cerebrum‐vermis ratio (P < 0.0001) than the healthy controls. SDS patients had structurally smaller posterior fossa and cerebellar vermis, corpus callosum, and brainstem than the healthy controls. The MRI findings may be related to the neuropsychological features described in SDS. © 2008 Wiley‐Liss, Inc.
Dispersal among male ring‐tailed lemurs (Lemur catta) on St. Catherines Island
Authors: Parga J. A. , Lessnau R. G. 
Published: May 2008

AbstractMale dispersal patterns were analyzed across a nine‐year period in a population of ring‐tailed lemurs (Lemur catta) on St. Catherines Island (SCI), USA, to evaluate two ultimate explanations for male dispersal: inbreeding avoidance and intrasexual mating competition. As part of this analysis, we also compared patterns of dispersal at this site with data from wild populations. Overall, we found that patterns of male intertroop movement on SCI are similar to the wild with respect to the frequency and seasonality of male transfer. In Madagascar, males move between groups every 3.1–3.5 years [Sussman, International Journal of Primatol 13:395–413, 1992; Koyama et al., Primates 43:291–314, 2002] as compared with every 3.2 years on SCI. The majority of transfers on SCI occurred during the birth season, as occurs at one site in Madagascar, Berenty [Budnitz & Dainis, Lemur biology. New York: Plenum Press, p 219–235, 1975; Jones, Folia Primatologica 40:145–160, 1983]. One difference is that males perform natal transfers 1–2 years earlier on SCI than in the wild, which may be related to food provisioning on SCI. Males never transferred back into their natal troops, which is remarkable given the small number of groups on SCI. Although this pattern of movement can indicate inbreeding avoidance by males, the fact that male troop tenure was in many cases long enough to overlap with the sexual maturation of potential daughters did not support the inbreeding avoidance hypothesis for male secondary dispersal. Instead, the intrasexual competition hypothesis was strongly supported, because males were significantly more likely to transfer into groups having fewer adult males and a more favorable sex ratio than their pretransfer groups. Males therefore appear to be bypassing groups in which they would experience a greater degree of intrasexual mating competition during the breeding season. Am. J. Primatol. 70:650–660, 2008. © 2008 Wiley‐Liss, Inc.
Data processing issues in large‐area GPR surveys: correcting trace misalignments, edge discontinuities and striping
Authors: Ernenwein Eileen G. , Kvamme Kenneth L. 
Published: May 2008

AbstractGround‐penetrating radar (GPR) lags behind other archaeogeophysical methods in terms of speed, efficiency and ability to produce clean site‐wide composites owing to complex and time‐consuming data processing requirements. Two North American case studies illustrate problems that occur when survey is conducted over long and short periods of time. Some GPR defects have been blamed on differential solar heating of antennae and battery power levels but we show these effects to be negligible. Major problems include gradual changes over time in ground moisture and low‐level background noise, which can create discontinuities between adjacent survey blocks when data are collected at different times. These problems are often remedied by globally aligning traces using a stable trace position. Variations in ground moisture through time also cause differences in reflection amplitudes, necessitating different range gain curves to match amplitudes between survey blocks. In some cases changes in ground moisture cause noticeable differences in velocity between survey blocks requiring time‐scales to be converted to depths to correctly match the data. These problems must be remedied before horizontal slicing can be considered. Subsequent image processing may also be necessary to generate a seamless mosaic and eliminate striping artefacts commonly seen in slice maps. The latter are probably caused by antenna lift and tilt and can be removed by a de‐striping algorithm that uses a one‐dimensional low‐pass filter to characterize stripes followed by their subtraction from the data. Copyright © 2008 John Wiley & Sons, Ltd.
Toward a theory of network gatekeeping: A framework for exploring information control
Authors: Barzilai‐Nahon Karine 
Published: May 2008

AbstractGatekeeping theories have been a popular heuristic for describing information control for years, but none have attained a full theoretical status in the context of networks. This article aims to propose a theory ofnetwork gatekeepingcomprised of two components:identificationandsalience.Network gatekeeping identificationlays out vocabulary and naming foundations through the identification of gatekeepers, gatekeeping, and gatekeeping mechanisms.Network gatekeeping salience, which is built on the bases of the network identification theory, utilizes this infrastructure to understand relationships among gatekeepers and between gatekeepers and gated, the entity subjected to a gatekeeping process. Network gatekeeping salience1Salience refers to the degree to which gatekeepers give priority to competing gated claims.proposes identifying gated and their salience to gatekeepers by four attributes: (a) theirpolitical powerin relation to the gatekeeper, (b) theirinformation production ability, (c) theirrelationshipwith the gatekeeper, and (d) theiralternativesin the context of gatekeeping.
The multiple directions of evolutionary change
Authors: Rasskin‐Gutman Diego , Esteve‐Altava Borja 
Published: May 2008

AbstractThe theory of Punctuated Equilibria challenges the neo‐Darwinian tenet that evolution is a uniform process. Recently, an article by Hunt1 has found that directional change during the evolution of a lineage is relatively small (occurring only in 5% of 250 analyzed traits). Of those traits that were shown to follow a trend, size was more likely to show gradual changes, whereas shape changes were more random. Here, we provide a short view of the nature of evolutionary trends, showing that directional change within lineages and among clades provides valuable evolutionary information about the processes involved in their generation. BioEssays 30:521–525, 2008. © 2008 Wiley Periodicals, Inc.
The origin and evolution of the neural crest
Authors: Donoghue Philip C.J. , Graham Anthony , Kelsh Robert N. 
Published: May 2008

AbstractMany of the features that distinguish the vertebrates from other chordates are derived from the neural crest, and it has long been argued that the emergence of this multipotent embryonic population was a key innovation underpinning vertebrate evolution. More recently, however, a number of studies have suggested that the evolution of the neural crest was less sudden than previously believed. This has exposed the fact that neural crest, as evidenced by its repertoire of derivative cell types, has evolved through vertebrate evolution. In this light, attempts to derive a typological definition of neural crest, in terms of molecular signatures or networks, are unfounded. We propose a less restrictive, embryological definition of this cell type that facilitates, rather than precludes, investigating the evolution of neural crest. While the evolutionary origin of neural crest has attracted much attention, its subsequent evolution has received almost no attention and yet it is more readily open to experimental investigation and has greater relevance to understanding vertebrate evolution. Finally, we provide a brief outline of how the evolutionary emergence of neural crest potentiality may have proceeded, and how it may be investigated. BioEssays 30:530–541, 2008. © 2008 Wiley Periodicals, Inc.
Positive feedback in cellular control systems
Authors: Mitrophanov Alexander Y. , Groisman Eduardo A. 
Published: May 2008

AbstractFeedback loops have been identified in a variety of regulatory systems and organisms. While feedback loops of the same type (negative or positive) tend to have properties in common, they can play distinctively diverse roles in different regulatory systems, where they can affect virulence in a pathogenic bacterium, maturation patterns of vertebrate oocytes and transitions through cell cycle phases in eukaryotic cells. This review focuses on the properties and functions of positive feedback in biological systems, including bistability, hysteresis and activation surges. BioEssays 30:542–555, 2008. © 2008 Wiley Periodicals, Inc.
Density Functional Theory Study of trans‐Dioxo Complexes of Iron, Ruthenium, and Osmium with Saturated Amine Ligands, trans‐[M(O)2(NH3)2(NMeH2)2]2+ (M=Fe, Ru, Os), and Detection of [Fe(qpy)(O)2]n+ (n=1, 2) by High‐Resolution ESI Mass Spectrometry
Authors: Tong Glenna So Ming , Wong Ella Lai‐Ming , Che Chi‐Ming 
Published: May 2008

AbstractDensity functional theory (DFT) calculations on trans‐dioxo metal complexes containing saturated amine ligands, trans‐[M(O)2(NH3)2(NMeH2)2]2+ (M=Fe, Ru, Os), were performed with different types of density functionals (DFs): 1) pure generalized gradient approximations (pure GGAs): PW91, BP86, and OLYP; 2) meta‐GGAs: VSXC and HCTH407; and 3) hybrid DFs: B3LYP and PBE1PBE. With pure GGAs and meta‐GGAs, a singlet d2 ground state for trans‐[Fe(O)2(NH3)2(NMeH2)2]2+ was obtained, but a quintet ground state was predicted by the hybrid DFs B3LYP and PBE1PBE. The lowest transition energies in water were calculated to be at λ≈509 and 515 nm in the respective ground‐state geometries from PW91 and B3LYP calculations. The nature of this transition is dependent on the DFs used: a ligand‐to‐metal charge‐transfer (LMCT) transition with PW91, but a π(FeO)→π*(FeO) transition with B3LYP, in which π and π* are the bonding and antibonding combinations between the dπ(Fe) and pπ(O2−) orbitals. The FeVI/V reduction potential of trans‐[Fe(O)2(NH3)2(NMeH2)2]2+ was estimated to be +1.30 V versus NHE based on PW91 results. The [Fe(qpy)(O)2]n+ (qpy=2,2′:6′,2′′:6′′,2′′′:6′′′,2′′′′‐quinquepyridine; n=1 and 2) ions, tentatively assigned to dioxo iron(V) and dioxo iron(VI), respectively, were detected in the gas phase by high‐resolution ESI‐MS spectroscopy.
Single‐Walled Carbon Nanotubes Binding to Human Telomeric i‐Motif DNA Under Molecular‐Crowding Conditions: More Water Molecules Released
Authors: Zhao Chao , Ren Jinsong , Qu Xiaogang 
Published: May 2008

AbstractThe natural occurrence of the human telomeric G‐quadruplex or i‐motif in vivo has not been demonstrated and the biological effects of the induction of these structures need to be clarified. Intracellular environments are highly crowded with various biomolecules and in vitro studies under molecular‐crowding conditions will provide important information on how biomolecules behave in cells. Here we report that cell‐mimic crowding can increase i‐motif stability at acid pH and cause dehydration. However, crowding can not induce i‐motif formation at physiological pH. Intriguingly, single‐walled carbon nanotubes (SWNTs) can drive i‐motif formation under cell‐mimic crowding conditions and cause more water to be released. To our knowledge, there is no report to show how SWNTs can influence DNA under cell‐mimic crowding conditions. Our results indicate that SWNTs may have the potential to modulate the structure of human telomeric DNA in vivo, like DNA B–A transitions and B–Z changes on SWNTs in live cells, which demonstrates potential for drug design and cancer therapy.
Hydrogen‐Bond‐Directed Catalysis: Faster, Regioselective and Cleaner Heck Arylation of Electron‐Rich Olefins in Alcohols
Authors: Hyder Zeynab , Ruan Jiwu , Xiao Jianliang 
Published: May 2008

AbstractA general method for the regioselective Heck reaction of electron‐rich olefins is presented. Fast, highly regioselective Pd‐catalysed α‐arylation of electron‐rich olefins, vinyl ethers (1 a–d), hydroxyl vinyl ethers (1 e, f), enamides (1 g, h) and a substituted vinyl ether (1 i) has been accomplished with a diverse range of aryl bromides (2 a–r), for the first time, in cheap, green and easily available alcohols with no need for any halide scavengers or salt additives. The reaction proceeds with high efficiency, leading exclusively to the α‐products, in 2‐propanol and particularly in ethylene glycol. In the latter, the arylation can be catalysed at a palladium loading of 0.1 mol % and finish in as short a time as 0.5 h. The remarkable performance of the alcohol solvents in promoting α regiocontrol is attributed to their hydrogen‐bond‐donating capability, which is believed to facilitate the dissociation of halide anions from PdII, and hence, the generation of a key ionic PdII–olefin intermediate responsible for the α product. This belief is further strengthened by the study of a benchmark arylation reaction in 21 different solvents. The study revealed that exclusive α‐regioselective arylation takes place in almost all of the protic solvents, and there is a rough correlation between the α‐arylation rates and the solvent parameter ETN. The method is simpler, cleaner and more general than those established thus far.
Neural circuits revealed by axon tracing and mapping cadherin expression in the embryonic chicken cerebellum
Authors: Neudert Franziska , Redies Christoph 
Published: May 2008

AbstractFiber connections of the cerebellar cortex are organized into distinct parasagittal domains. Each domain expresses a unique subset of various genes. Brain structures that are directly connected to the cerebellar cortex, such as the deep cerebellar nuclei and the inferior olivary nucleus, show a similarly differential pattern of connectivity and gene expression. For example, several members of the cadherin family of adhesion molecules are expressed differentially in the subdivisions of the cerebellar system in chicken and mouse. Little is known, however, about how the molecular maps in the different parts of the cerebellum relate to each other in terms of connectivity. Here, we mapped the expression of three cadherins (cadherin‐8, protocadherin‐7, and protocadherin‐10) in the cerebellar system of the chicken embryo. By simultaneously tracing axonal connections with biotinylated dextran amine, we demonstrate that cortical domains and deep nuclear portions as well as their fiber connections have a matching expression profile for protocadherin‐10 in the posterior part of the cerebellum. Based on the tracing results for protocadherin‐10 and the comparative expression mapping of all three cadherins, the cortical projection domains of the three deep cerebellar nuclei were determined in the posterior part of the cerebellum. Results were extrapolated to the rest of the cerebellar cortex. Our results provide direct experimental support for the notion that cadherins are markers for neural circuits in the brain. Moreover, we show that the expression pattern of all three cadherins confers unique identities to the Purkinje cell domains. J. Comp. Neurol. 509:283–301, 2008. © 2008 Wiley‐Liss, Inc.