bluuebunny/crossref_metadata_2025 huggingface dataset:
Conveyor belt effect in the flow through a planar duct of a viscous fluid with spinning particles
Authors: Felderhof B. U.
Published: August 2012

The extended Navier-Stokes equations describing the steady-state hydrodynamics of a viscous fluid with spinning particles are solved for flow through a planar duct. The flow caused by an applied torque density in the transverse direction and linear in the transverse coordinate is compared with the flow caused by a uniform applied force density in the longitudinal direction. In both cases the flow velocity is of Poiseuille type plus a correction. In the first case the flow velocity is caused by the conveyor belt effect of spinning particles. The corrections to the Poiseuille flow pattern in the two cases differ only by a proportionality factor. The spin rate profiles in the two cases are also proportional.
Turbulent mixing and wave radiation in non-Boussinesq internal bores
Authors: Borden Zac , Koblitz Tilman , Meiburg Eckart
Published: August 2012

Bores, or hydraulic jumps, appear in many natural settings and are useful in many industrial applications. If the densities of the two fluids between which a bore propagates are very different (i.e., water and air), the less dense fluid can be neglected when modeling a bore analytically—a single-layer hydraulic model will accurately predict a bore's speed of propagation. A two-layer model is required, however, if the densities are more similar. Mass is conserved separately in each layer and momentum is conserved globally, but the model requires for closure an assumption about the loss of energy across a bore. In the Boussinesq limit, it is known that there is a decrease of the total energy flux across a bore, but in the expanding layer, turbulent mixing at the interface entrains high speed fluid from the contracting layer, resulting in an increase in the flux of kinetic energy across the expanding layer of a bore. But it is unclear if this finding will extend to non-Boussinesq bores. We directly examine the flux of energy within non-Boussinesq bores using two-dimensional direct numerical simulations and find that a gain of energy across the expanding layer only occurs for bores where the density ratio, defined as the ratio of the density of the lighter fluid to the heavier fluid, is greater than approximately one half. For smaller density ratios, undular waves generated at the bore's front dominate over the effects of turbulent mixing, and the expanding layer loses energy across the bore. Based on our results, we show that if one can predict the amount of energy radiated by bores through undular waves, it is possible to derive an accurate model for the propagation of non-Boussinesq bores.
Multiple current reversals and diffusion enhancement in a symmetrical periodic potential
Authors: Zeng Chunhua , Wang Hua , Nie Linru
Published: August 2012

Transport and diffusion of Brownian particles in a symmetrical periodic potential were investigated for both overdamped and underdamped cases, where the ratchet potential is driven by an external unbiased time periodic force and correlation between thermal and potential fluctuations. It is shown that the correlation between two noises breaks the symmetry of the potential to generate motion of the Brownian particles in particular direction, and the current can reverse its direction by changing the sign of the noise correlation. For the overdamped case, the systemic parameters only induce the directed current, and the noise correlation suppresses the diffusion of the overdamped Brownian particles. However for the underdamped case, the current reverses its direction multiple times with increasing the systemic parameters, i.e., the multiple current reversal is observed, and the noise negative correlation suppresses the diffusion of the underdamped Brownian particles, while the noise positive correlation enhances it.
Ideal stochastic forcing for the motion of particles in large-eddy simulation extracted from direct numerical simulation of turbulent channel flow
Authors: Geurts B. J. , Kuerten J. G. M.
Published: August 2012

The motion of small particles in turbulent conditions is influenced by the entire range of length- and time-scales of the flow. At high Reynolds numbers this range of scales is too broad for direct numerical simulation (DNS). Such flows can only be approached using large-eddy simulation (LES), which requires the introduction of a sub-filter model for the momentum dynamics. Likewise, for the particle motion the effect of sub-filter scales needs to be reconstructed approximately, as there is no explicit access to turbulent sub-filter scales. To recover the dynamic consequences of the unresolved scales, partial reconstruction through approximate deconvolution of the LES-filter is combined with explicit stochastic forcing in the equations of motion of the particles. We analyze DNS of high-Reynolds turbulent channel flow to a priori extract the ideal forcing that should be added to retain correct statistical properties of the dispersed particle phase in LES. The probability density function of the velocity differences that need to be included in the particle equations and their temporal correlation display a striking and simple structure with little dependence on Reynolds number and particle inertia, provided the differences are normalized by their RMS, and the correlations expressed in wall units. This is key to the development of a general “stand-alone” stochastic forcing for inertial particles in LES.
The E3 ubiquitin ligase MARCH8 negatively regulates IL-1β-induced NF-κB activation by targeting the IL1RAP coreceptor for ubiquitination and degradation
Authors: Chen Rui , Li Mi , Zhang Yu , Zhou Qian , Shu Hong-Bing
Published: August 2012

The proinflammatory cytokine interleukin-1 (IL-1) signals via type I IL-1 receptor (IL-1RI) and IL-1 receptor accessory protein (IL1RAP), which leads to activation of the transcription factor NF-κB and induction of a range of downstream proteins involved in inflammatory and immune responses. Here, we identified the E3 ubiquitin ligase membrane-associated RING-CH (MARCH8) as a suppressor of IL-1β–induced NF-κB- and MAPK-activation pathways. Overexpression of MARCH8 inhibits IL-1β–induced NF-κB and MAPK activation, whereas knockdown of MARCH8 has the opposite effect. Mechanistically, MARCH8 interacts with IL1RAP and targets its Lys512 for K48-linked polyubiquitination and degradation. Our findings suggest that MARCH8-mediated polyubiquitination and degradation of IL1RAP is an important mechanism for negative regulation of IL-1β–induced signaling pathways.
Genetic and environmental risk factors in congenital heart disease functionally converge in protein networks driving heart development
Authors: Lage Kasper , Greenway Steven C. , Rosenfeld Jill A. , Wakimoto Hiroko , Gorham Joshua M. , Segrè Ayellet V. , Roberts Amy E. , Smoot Leslie B. , Pu William T. , C. Pereira Alexandre , Mesquita Sonia M. , Tommerup Niels , Brunak Søren , Ballif Blake C. , Shaffer Lisa G. , Donahoe Patricia K. , Daly Mark J. , Seidman Jonathan G. , Seidman Christine E. , Larsen Lars A.
Published: August 2012

Congenital heart disease (CHD) occurs in ∼1% of newborns. CHD arises from many distinct etiologies, ranging from genetic or genomic variation to exposure to teratogens, which elicit diverse cell and molecular responses during cardiac development. To systematically explore the relationships between CHD risk factors and responses, we compiled and integrated comprehensive datasets from studies of CHD in humans and model organisms. We examined two alternative models of potential functional relationships between genes in these datasets: direct convergence, in which CHD risk factors significantly and directly impact the same genes and molecules and functional convergence, in which risk factors significantly impact different molecules that participate in a discrete heart development network. We observed no evidence for direct convergence. In contrast, we show that CHD risk factors functionally converge in protein networks driving the development of specific anatomical structures (e.g., outflow tract, ventricular septum, and atrial septum) that are malformed by CHD. This integrative analysis of CHD risk factors and responses suggests a complex pattern of functional interactions between genomic variation and environmental exposures that modulate critical biological systems during heart development.
Global environmental predictors of benthic marine biogeographic structure
Authors: Belanger Christina L. , Jablonski David , Roy Kaustuv , Berke Sarah K. , Krug Andrew Z. , Valentine James W.
Published: August 2012

Analyses of how environmental factors influence the biogeographic structure of biotas are essential for understanding the processes underlying global diversity patterns and for predicting large-scale biotic responses to global change. Here we show that the large-scale geographic structure of shallow-marine benthic faunas, defined by existing biogeographic schemes, can be predicted with 89–100% accuracy by a few readily available oceanographic variables; temperature alone can predict 53–99% of the present-day structure along coastlines. The same set of variables is also strongly correlated with spatial changes in species compositions of bivalves, a major component of the benthic marine biota, at the 1° grid-cell resolution. These analyses demonstrate the central role of coastal oceanography in structuring benthic marine biogeography and suggest that a few environmental variables may be sufficient to model the response of marine biogeographic structure to past and future changes in climate.
The Long‐Term Illinois River Fish Population Monitoring Program
Authors: McClelland Michael A. , Sass Greg G. , Cook Thad R. , Irons Kevin S. , Michaels Nerissa N. , O'Hara T. Matthew , Smith Cammy S.
Published: August 2012

Long‐term ecological monitoring is essential to gain an understanding of the interaction between spatial and temporal patterns and variability. The goals of our study were to test for trends in (1) overall fish catches; (2) native and non‐native fish species richness and relative abundance; and (3) the fish species assemblages over time using greater than 50 years offish population data collected from the Illinois River. Fish species richness increased over time and community analyses revealed changes in fish species composition from a community dominated by common carp (Cyprinus carpio) and goldfish (Carassius auratus) to one of greater species diversity. Prior to 1976, abundances of native fish species were declining significantly but have since shown a significant increase. Abundances of nonnative species declined from 1957 to 2000; however, rapid population growth of Asian carps (Hypophthalmichthys spp.) in the Illinois River increased nonnative fish species catches. Many of the trends observed may reflect positive effects of rehabilitation efforts throughout the Illinois River. Our collections highlight the importance of long‐term monitoring programs to detect temporal and spatial shifts in fish populations in the context of anthropogenic and natural change in aquatic ecosystems.
Enhanced dielectric and magnetic properties in Ru-substituted Bi0.9La0.1FeO3 ceramics
Authors: Gong Y F , Wu P , Hai X , Liu W F , Wang S Y , Liu G Y , Rao G H
Published: August 2012

Multiferroic ceramics Bi0.9La0.1Fe1−x
Ru
x
O3 (x = 0%, 1% and 3%) were prepared using a solid-state reaction process. The structural transformation from rhombohedral to pseudocubic was confirmed in the Ru-doped samples via x-ray diffraction investigation, and the improved dielectric properties are ascribed to the morphotropic phase boundary and decreased oxygen defects existing in the Ru-substituted samples. The enhancement of magnetization is interpreted by the increased Fe3+ ions and the formation of a local ‘ferrimagnetic’ structure in the Ru-doped samples.
Microlenticular lens replication by the combination of gas-assisted imprint technology and LIGA-like process
Authors: Yeh Chia-Hung , Shih Ching-Jui , Wang Hsuan-Cheng , Chang Fuh-Yu , Young Hong-Tsu , Chang Wen-Chuan
Published: August 2012

A mold used in creating diffractive optical elements significantly affects the quality of these devices. In this study, we improved traditional microlens fabrication processes, which have shortcomings, mainly by combining gas-assisted imprint technology and the lithographie galvanoformung abformung (LIGA)-like process. This combination resulted in the production of high-quality optical components with high replication rates, high uniformity, large areas and high flexibility. Given the pixel size of the panel used, the optimal viewing distance, the film thickness and the glass thickness in the formula, we could determine the radius of curvature and the thickness of the lens. By the use of U-groove machining, precise electroforming and embossing to produce polydimethylsiloxane (PDMS) molds, lens film elements can be produced via an ultraviolet (UV)-cured molding process that converts microlenses into flexible polyethylene terephthalate films. In this study, the microlenticular lens mold is fabricated by U-groove machining, Ni electroforming and PDMS casting. Then, the PDMS mold with microlenticular lens structure is used in the gas-assisted UV imprint process and the PET film with microlenticular lens array is obtained. The lenticular lens had a radius of curvature and height of 228 and 18 µm, respectively. A 3D confocal laser microscope was used to measure the radius of curvature and the spacing of the metal molds, nickel (Ni) molds, PDMS molds and the finished thin-film products. The geometry of the final microlenticular lens was very close to the design values. All geometric errors were below 5%, the surface roughness reached the optical level (with all Ra values less than 10 nm) and the replication rate was 95%. The results demonstrate that this process can be used to fabricate gapless, lenticular-shaped, high-precision microlens arrays with a unitary curvature.
On the volume of complex amoebas
Authors: Madani Farid , Nisse Mounir
Published: August 2012

The paper deals with amoebas of

k
k

-dimensional algebraic varieties in the complex algebraic torus of dimension

n
≥
2
k

n\geq 2k

. First, we show that the area of complex algebraic curve amoebas is finite. Moreover, we give an estimate of this area in the rational curve case in terms of the degree of the rational parametrization coordinates. We also show that the volume of the amoeba of a

k
k

-dimensional algebraic variety in

(

C

∗

)

n

(\mathbb {C}^*)^{n}

, with

n
≥
2
k

n\geq 2k

, is finite.
Imp2 controls oxidative phosphorylation and is crucial for preserving glioblastoma cancer stem cells
Authors: Janiszewska Michalina , Suvà Mario L. , Riggi Nicolo , Houtkooper Riekelt H. , Auwerx Johan , Clément-Schatlo Virginie , Radovanovic Ivan , Rheinbay Esther , Provero Paolo , Stamenkovic Ivan
Published: August 2012

Growth of numerous cancer types is believed to be driven by a subpopulation of poorly differentiated cells, often referred to as cancer stem cells (CSCs), that have the capacity for self-renewal, tumor initiation, and generation of nontumorigenic progeny. Despite their potentially key role in tumor establishment and maintenance, the energy requirements of these cells and the mechanisms that regulate their energy production are unknown. Here, we show that the oncofetal insulin-like growth factor 2 mRNA-binding protein 2 (IMP2, IGF2BP2) regulates oxidative phosphorylation (OXPHOS) in primary glioblastoma (GBM) sphere cultures (gliomaspheres), an established in vitro model for CSC expansion. We demonstrate that IMP2 binds several mRNAs that encode mitochondrial respiratory chain complex subunits and that it interacts with complex I (NADH:ubiquinone oxidoreductase) proteins. Depletion of IMP2 in gliomaspheres decreases their oxygen consumption rate and both complex I and complex IV activity that results in impaired clonogenicity in vitro and tumorigenicity in vivo. Importantly, inhibition of OXPHOS but not of glycolysis abolishes GBM cell clonogenicity. Our observations suggest that gliomaspheres depend on OXPHOS for their energy production and survival and that IMP2 expression provides a key mechanism to ensure OXPHOS maintenance by delivering respiratory chain subunit-encoding mRNAs to mitochondria and contributing to complex I and complex IV assembly.
C16orf57, a gene mutated in poikiloderma with neutropenia, encodes a putative phosphodiesterase responsible for the U6 snRNA 3′ end modification
Authors: Mroczek Seweryn , Krwawicz Joanna , Kutner Jan , Lazniewski Michal , Kuciński Iwo , Ginalski Krzysztof , Dziembowski Andrzej
Published: August 2012

C16orf57encodes a human protein of unknown function, and mutations in the gene occur in poikiloderma with neutropenia (PN), which is a rare, autosomal recessive disease. Interestingly, mutations inC16orf57were also observed among patients diagnosed with Rothmund-Thomson syndrome (RTS) and dyskeratosis congenita (DC), which are caused by mutations in genes involved in DNA repair and telomere maintenance. A genetic screen inSaccharomyces cerevisiaerevealed that the yeast ortholog ofC16orf57,USB1(YLR132C), is essential for U6 small nuclear RNA (snRNA) biogenesis and cell viability. Usb1 depletion destabilized U6 snRNA, leading to splicing defects and cell growth defects, which was suppressed by the presence of multiple copies of the U6 snRNA geneSNR6. Moreover, Usb1 is essential for the generation of a unique feature of U6 snRNA; namely, the 3′-terminal phosphate. RNAi experiments in human cells followed by biochemical and functional analyses confirmed that, similar to yeast,C16orf57encodes a protein involved in the 2′,3′-cyclic phosphate formation at the 3′ end of U6 snRNA. Advanced bioinformatics predicted thatC16orf57encodes a phosphodiesterase whose putative catalytic activity is essential for its function in vivo. Our results predict an unexpected molecular basis for PN, DC, and RTS and provide insight into U6 snRNA 3′ end formation.
Infantile amnesia: A neurogenic hypothesis
Authors: Josselyn Sheena A. , Frankland Paul W.
Published: August 2012

In the late 19th Century, Sigmund Freud described the phenomenon in which people are unable to recall events from early childhood as infantile amnesia. Although universally observed, infantile amnesia is a paradox; adults have surprisingly few memories of early childhood despite the seemingly exuberant learning capacity of young children. How can these findings be reconciled? The mechanisms underlying this form of amnesia are the subject of much debate. Psychological/cognitive theories assert that the ability to maintain detailed, declarative-like memories in the long term correlates with the development of language, theory of mind, and/or sense of “self.” However, the finding that experimental animals also show infantile amnesia suggests that this phenomenon cannot be explained fully in purely human terms. Biological explanations of infantile amnesia suggest that protracted postnatal development of key brain regions important for memory interferes with stable long-term memory storage, yet they do not clearly specify which particular aspects of brain maturation are causally related to infantile amnesia. Here, we propose a hypothesis of infantile amnesia that focuses on one specific aspect of postnatal brain development—the continued addition of new neurons to the hippocampus. Infants (humans, nonhuman primates, and rodents) exhibit high levels of hippocampal neurogenesis and an inability to form lasting memories. Interestingly, the decline of postnatal neurogenesis levels corresponds to the emergence of the ability to form stable long-term memory. We propose that high neurogenesis levels negatively regulate the ability to form enduring memories, most likely by replacing synaptic connections in preexisting hippocampal memory circuits.
The molecular basis of cognitive deficits in pervasive developmental disorders: Table 1.
Authors: Bhattacharya Aditi , Klann Eric
Published: August 2012

Persons with pervasive developmental disorders (PDD) exhibit a range of cognitive deficits that hamper their quality of life, including difficulties involving communication, sociability, and perspective-taking. In recent years, a variety of studies in mice that model genetic syndromes with a high risk of PDD have provided insights into the underlying molecular mechanisms associated with these disorders. What is less appreciated is how the molecular anomalies affect neuronal and circuit function to give rise to the cognitive deficits associated with PDD. In this review, we describe genetic mutations that cause PDD and discuss how they alter fundamental social and cognitive processes. We then describe efforts to correct cognitive impairments associated with these disorders and identify areas of further inquiry in the search for molecular targets for therapeutics for PDD.
New approaches to neural circuits in behavior
Authors: Garner Aleena , Mayford Mark
Published: August 2012

A fundamental goal of neuroscience is to understand how the brain represents the world. If we consider the neurons of the brain to be one system and the external world to be another system, how do the two systems interact, and by what translational code does the former represent the latter? Recent advances in imaging neural activity, genetically altering specific neural circuits, and genetic tools for the direct manipulation of neural activity are beginning to shed light on this critical question. We review recent advances in these areas that illustrate a path to addressing this fundamental question.
MicroRNAs in learning, memory, and neurological diseases: Figure 1.
Authors: Wang Wenyuan , Kwon Ester J. , Tsai Li-Huei
Published: August 2012

MicroRNAs (miRNAs) represent a class of small regulatory noncoding RNAs ∼22 bp in length that mediate post-transcriptional silencing of gene expression via the recognition of specific sequences in target messenger (m)RNAs. The current body of literature suggests that miRNAs are fine-tuning regulators of gene expression profiles in a wide range of biological processes, from development to cancer. Many miRNAs are highly expressed in the adult nervous system in a spatially and temporally controlled manner in normal physiology, as well as in certain pathological conditions. These findings emphasize that gene regulation networks based on miRNA activities may be particularly important to brain function, and that perturbation of these networks may result in abnormal brain function. Indeed, miRNAs have been implicated in various aspects of dendrite remodeling and synaptic plasticity, as well as in experience-dependent adaptive changes of neural circuits in the postnatal developmental and adult brain. Recent advances in methods of next-generation sequencing, such as RNA-seq, offer the means to quantitatively evaluate the functions of miRNAs in a genome-wide manner in large cohorts of samples. These new technologies have already yielded valuable information and are expanding our understanding of miRNA-based mechanisms in higher-order brain processing, including learning and memory and cognition, as well as in neuropsychiatric disorders.
Neural functions of calcineurin in synaptic plasticity and memory: Figure 1.
Authors: Baumgärtel Karsten , Mansuy Isabelle M.
Published: August 2012

Major brain functions depend on neuronal processes that favor the plasticity of neuronal circuits while at the same time maintaining their stability. The mechanisms that regulate brain plasticity are complex and engage multiple cascades of molecular components that modulate synaptic efficacy. Protein kinases (PKs) and phosphatases (PPs) are among the most important of these components that act as positive and negative regulators of neuronal signaling and plasticity, respectively. In these cascades, the PP protein phosphatase 2B or calcineurin (CaN) is of particular interest because it is the only Ca2+-activated PP in the brain and a major regulator of key proteins essential for synaptic transmission and neuronal excitability. This review describes the primary properties of CaN and illustrates its functions and modes of action by focusing on several representative targets, in particular glutamate receptors, striatal enriched protein phosphatase (STEP), and neuromodulin (GAP43), and their functional significance for synaptic plasticity and memory.
LONO1Encoding a Nucleoporin Is Required for Embryogenesis and Seed Viability in Arabidopsis
Authors: Braud Christopher , Zheng Wenguang , Xiao Wenyan
Published: August 2012

Early embryogenesis in Arabidopsis (Arabidopsis thaliana) is distinguished by a predictable pattern of cell divisions and is a good system for investigating mechanisms of developmental pattern formation. Here, we identified a gene called LONO1 (LNO1) in Arabidopsis in which mutations can abolish the first asymmetrical cell division of the zygote, alter planes and number of cell divisions in early embryogenesis, and eventually arrest embryo development. LNO1 is highly expressed in anthers of flower buds, stigma papilla of open flowers, and embryo and endosperm during early embryogenesis, which is correlated with its functions in reproductive development. The homozygous lno1-1 seed is not viable. LNO1, a homolog of the nucleoporin NUP214 in human (Homo sapiens) and Nup159 in yeast (Saccharomyces cerevisiae), encodes a nucleoporin protein containing phenylalanine-glycine repeats in Arabidopsis. We demonstrate that LNO1 can functionally complement the defect in the yeast temperature-sensitive nucleoporin mutant nup159. We show that LNO1 specifically interacts with the Arabidopsis DEAD-box helicase/ATPase LOS4 in the yeast two-hybrid assay. Furthermore, mutations in AtGLE1, an Arabidopsis homolog of the yeast Gle1 involved in the same poly(A) mRNA export pathway as Nup159, also result in seed abortion. Our results suggest that LNO1 is a component of the nuclear pore complex required for mature mRNA export from the nucleus to the cytoplasm, which makes LNO1 essential for embryogenesis and seed viability in Arabidopsis.
Macrophyte species composition, distribution and diversity in relation to some physicochemical factors in the littoral zone of Lake Ziway, Ethiopia
Authors: Tamire Girum , Mengistou Seyoum
Published: August 2012

The species composition, distribution and diversity of macrophytes in Lake Ziway were determined at the end of dry and wet seasons along nine littoral sites during 2010 using a belt transect method. Some physicochemical parameters were also measured. Fourteen macrophyte species were identified with low species diversity for the lake (H' value of 1.805). The macrophyte species composition of the lake has undergone many changes during the last few decades. Arundo donax, which was never reported earlier, attained the highest relative density (30.7%) and frequency (30.5%) in this study, followed by Echinochloa colona, Potamogeton schweinfurthii, Cyperus articulatus, Typha latifolia and Cyperus papyrus. The average densities of A. donax, C. articulatus, E. colona and Pistia stratiotes were positively correlated with nutrients, whereas the density of the other species had negative correlation with physicochemical variables (CCA). Generally, the present macrophyte composition and abundance indicates healthy ecological condition of the lake. But if nutrient levels continue to increase and water levels continue to decline, we expect further changes in macrophyte composition and especially a shift towards invasive floating species.
Clinical aspects of using exhaled NO in asthma diagnosis and management
Authors: Ludviksdottir Dora , Diamant Zuzana , Alving Kjell , Bjermer Leif , Malinovschi Andrei
Published: August 2012

Background

Current guidelines recommend tailoring of asthma management according to disease control, which is largely defined by increased symptoms and deterioration in lung function. These features do not reflect the severity nor the type of the asthmatic airway inflammation. Fractional exhaled nitric oxide (FENO) is a simple, non‐invasive and cost‐effective online test applicable in both adults and children. In addition to symptoms and lung function measurements, FENO reflects airway eosinophilia and hence allows online assessment of the corticosteroid‐sensitive T helper 2 type airway inflammation in asthmatic patients. FENO can thus be applied to aid asthma diagnosis and treatment monitoring both in clinical practice and for research purposes.

Objectives

The scope of this review is to provide an overview of the most important clinical studies using FENO in asthma management and to summarise the implications of FENO measurements in clinical practice.

Results and Conclusion

In several studies, FENO measurements provided additional information on aspects of asthma including phenotyping, corticosteroid‐responsiveness and disease control. Thus, if correctly applied and interpreted, FENO can aid asthma diagnosis, identify patients at risk of exacerbation and support customized treatment decisions. A simple and reliable tool to quantify peripheral nitric oxide will further aid to identify patients with small airways inflammation.
Age and growth and maturity of southern Africa's largest cyprinid fish, the largemouth yellowfish Labeobarbus kimberleyensis
Authors: Ellender B. R. , Weyl O. L. F. , Winker H.
Published: August 2012

The aim of this study was to use specimens of the largemouth yellowfish Labeobarbus kimberleyensis, southern Africa's largest cyprinid [IUCN red‐listed as Near Threatened (NT)], obtained from gillnet by‐catch to describe aspects of its biology in order to assist future conservation and management decisions. Ninety three L. kimberleyensis were collected between March 2007 and May 2008 from Lake Gariep, South Africa. Labeobarbus kimberleyensis was present in 38% of all gillnet catches, but in low numbers (2% of the catch) and it contributed 8% to the catch by mass. Age was estimated using astericus otoliths. Growth increment formation on these otoliths was validated as annual using edge analysis and the mark‐recapture of chemically tagged captive fish. Resultant analysis showed that the species is slow growing and the oldest aged fish was a 17 year, 690 mm fork length (LF) male. The smallest ripe female fish measured 394 mm LF and was 7+ years old and the smallest mature male was 337 mm LF and 5+ years old. Slow growth and late maturity make this species vulnerable to exploitation emphasizing the need for continued high conservation priority.
Phylogenetic relationships of a Patagonian frog radiation, the Alsodes + Eupsophus clade (Anura: Alsodidae), with comments on the supposed paraphyly of Eupsophus
Authors: Blotto Boris L. , Nuñez José J. , Basso Néstor G. , Úbeda Carmen A. , Wheeler Ward C. , Faivovich Julián
Published: August 2012

The frog clade composed of the alsodid genera Alsodes + Eupsophus is the most species‐rich of the Patagonian endemic frog clades, including nearly 31 of the slightly more than 50 species of that region. The biology of this group of frogs is poorly known, its taxonomy quite complex (particularly Alsodes), and its diversity in chromosome number striking when compared with other frogs (collectively, there are species having 2n = 22, 2n = 26, 2n = 28, 2n = 30 or 2n = 34). We present a phylogenetic analysis of this Patagonian frog clade based on mitochondrial and nuclear gene sequences. We sequenced five mitochondrial genes (cytochrome b, cytochrome oxidase I, 12S, 16S, NADH dehydrogenase subunit 1) with three intervening tRNAs, and fragments of three nuclear genes (seven in absentia homolog 1, rhodopsin exon 1, RAG‐1), for a maximum of 6510 bp for multiple specimens from 26 of the 31 species. We recovered Eupsophus as polyphyletic, with E. antartandicus, E. sylvaticus, and E. taeniatus in Batrachylidae, in accordance with most previous hypotheses. Based on this result, we transfer E. antartandicus and E. taeniatus back to Batrachyla, and E. sylvaticus to Hylorina (resurrected from the synonymy of Eupsophus), remediating the paraphyly of Eupsophus. Our results strongly corroborate the monophyly of Alsodes + Eupsophus (sensu stricto), the individual monophyly of these genera, and the monophyly of the species groups of Eupsophus. They also show the non‐monophyly of all non‐monotypic species groups of Alsodes proposed in the past. Our results expose several taxonomic problems particularly in Alsodes, and to a lesser extent in Eupsophus. This phylogenetic context suggests a rich evolutionary history of karyotypic diversification in the clade, in part corroborating previous hypotheses. In Alsodes, we predict three independent transformations of chromosome number from the plesiomorphic 2n = 26. All these, strikingly, involve increments or reductions of pairs of haploid chromosomes. Finally, the phylogenetic pattern recovered for Alsodes and Eupsophus suggests a trans‐Andean origin and diversification of the group, with multiple, independent ingressions over cis‐Andean regions.
Plastid genomes and deep relationships among the commelinid monocot angiosperms
Authors: Barrett Craig F. , Davis Jerrold I. , Leebens‐Mack Jim , Conran John G. , Stevenson Dennis W.
Published: August 2012

The commelinid monocots comprise the orders Arecales (A), Commelinales (C), Poales sensu Angiosperm Phylogeny Group III (APGIII) (P), Zingiberales (Z), plus the unplaced family Dasypogonaceae (D), collectively containing numerous economically and ecologically important species and encompassing enormous morphological diversity. Commelinids are supported as monophyletic based on anatomy and molecular data; however, relationships among major commelinid groupings conflict among previous studies, representing a long‐standing problem in monocot systematics, with major implications for interpretations of character evolution. In more recent analyses, with whole‐plastome sampling largely focused on Poales, areas of conflict remain, suggesting the need for closer investigation of relationships and support. Here, we increased sampling of plastomes among non‐Poalean commelinid orders to investigate deep nodal support. Analysis of 83 plastid genes recovered relationships as ((A, D) (ZC, P)) with robust support, regardless of reconstruction method (parsimony/likelihood). However, conflict among genes was evident when grouped by genomic region. Cumulative analyses of genes ranked by decreasing numbers of informative characters indicated continued fluctuation in support, even as small genes were added to a nearly complete matrix, contrary to the expected pattern of stabilization in support. Topology tests among major commelinid groups suggested that the data were not powerful enough to reject all alternatives. This study provides clues to the limits of the plastid genome for resolving deep relationships among the commelinid monocots.
The Hypertension in the Very Elderly Trial – latest data
Authors: Mukhtar Omar , Jackson Stephen H. D.
Published: August 2012

Early trials in the field of hypertension focused on adults in their fifties and sixties. However, with the passage of time, a progressive effort has been made to expand the evidence base for treatment in older adults. 2008 saw publication of data from the Hypertension in the Very Elderly Trial which demonstrated significant mortality and morbidity benefits from antihypertensive therapy in octogenarians. More recently, additional data from this cohort has been published suggesting that appropriate anti‐hypertensive therapy may lead to a reduction in incident cognitive impairment and fractures, whilst a 1 year open label extension of the main study confirmed many of the original trial findings. This review provides an overview of the Hypertension in the Very Elderly Trial whilst also discursively evaluating the latest data.
Insulin promotes T cell recovery in a murine model of autoimmune myocarditis
Authors: Zhang Y , Zhuang R , Geng C , Cai X , Lei W , Tian N , Gao F
Published: August 2012

Glucose-insulin-potassium (GIK) is a useful adjunct to myocarditis. Besides its essential action in energy metabolism, insulin also exerts an anti-inflammatory effect. This study investigated the effect of insulin on myocardial inflammation in experimental autoimmune myocarditis (EAM) in mice and its potential role in T cell regulation. Mice were divided randomly into a normal control group, a saline-treated EAM group and an insulin-treated EAM group. The histopathological changes of myocardium, α-myosin heavy chain (MyHCα)614–629 antigen-specific autoantibody titre, the serum level of cardiac troponin I (cTnI), mitogen-activated protein kinase (MAPK) family members' activity and content were measured. Furthermore, the phenotype of T lymphocyte subsets in splenocytes was analysed to evaluate the immune status of mice. Insulin reduced serum cTnI of EAM mice on days 14 and 21 (P < 0·05) after immunization, with no changes in blood glucose and autoantibody production. Western blot revealed that extracellular signal-regulated protein kinase (ERK1/2) may be a determining factor in this process. Total ERK1/2 and phospho-ERK1/2 (p-ERK1/2) were both up-regulated in insulin-treated mice after immunization. We also found that insulin treatment promoted T cell recovery without changing the naive-to-memory T-cell ratio; in particular, CD3+ T cells in insulin-treated mice proliferated more vigorously than in control mice (P < 0·05). We report here for the first time that insulin alleviates myocarditis in the EAM model. These data show that insulin has a direct effect on T cell proliferation in EAM. It is possible that GIK or insulin may assist T cell recovery towards normal in myocarditis, especially for diabetic or hyperglycaemic patients.
Increased efficiency in the generation of induced pluripotent stem cells by Fbxw7 ablation
Authors: Okita Yasutaka , Matsumoto Akinobu , Yumimoto Kanae , Isoshita Rieko , Nakayama Keiichi I.
Published: August 2012

Induced pluripotent stem cells (iPSCs) share many biological properties with embryonic stem cells (ESCs), and are generated from somatic cells by expression of some transcription factors such as Oct3/4, Sox2, Klf4 and c‐Myc. Among these factors, the abundance of c‐Myc is strictly regulated by Fbxw7, a subunit of Skp1‐Cul1‐F‐box protein‐type ubiquitin ligase. We have now shown that the expression of Fbxw7 was increased as ESCs differentiated. To investigate the role of Fbxw7 in the ESCs/iPSCs, we examined the impact of Fbxw7 ablation in the efficiency in iPSC generation. The frequency of iPSC generation from mouse embryonic fibroblasts (MEFs) lacking Fbxw7 was markedly greater than that from control MEFs. Depletion of Fbxw7 also resulted in promotion of iPSC generation. Morphology of iPSC clonies from Fbxw7‐depleted MEFs appeared more undifferentiated than that from MEFs overexpressing c‐Myc. Additional depletion of c‐Myc did not abrogate the effect of Fbxw7 depletion, suggesting that c‐Myc accumulation is not necessarily required for the increased efficiency in iPSC generation by Fbxw7 ablation. Substrates of Fbxw7 other than c‐Myc might therefore play a key role in iPSC generation. These results suggest that transient inhibition of Fbxw7 would be a more promising approach to efficient generation of iPSCs than c‐Myc over‐expression.
BRCT domain of DNA polymerase μ has DNA‐binding activity and promotes the DNA polymerization activity
Authors: Matsumoto Takuro , Go Kaori , Hyodo Mariko , Koiwai Kotaro , Maezawa So , Hayano Takahide , Suzuki Masahiro , Koiwai Osamu
Published: August 2012

DNA polymerase μ (pol μ) catalyzes nonhomologous end‐joining in DNA double‐stranded break repair. Pol μ consists of an amino‐terminal BRCA1 carboxyl‐terminal homology (BRCT) domain and a pol β‐like region, which contains the catalytic site. By DNA cellulose column chromatography, using full‐length pol μ and five different deletion mutants, we found that the amino‐terminal region has double‐stranded DNA (dsDNA)‐binding activity. Pol μ without BRCT domain reduces the DNA polymerization activity when compared to full‐length pol μ. Observation by atomic force microscopy showed that full‐length pol μ binds to the ends and middle part of dsDNA. Pol μ lacking the amino‐terminal region or with a mutation within the BRCT domain bound only to DNA ends, whereas the amino‐terminal region with the BRCT domain bound to both the ends and the middle part of dsDNA (mpdDNA). Terminal deoxynucleotidyltransferase, which, like pol μ, belongs to the X family DNA polymerases, also bound to mpdDNA through its amino‐terminal region.
The international school nurse asthma project: barriers related to asthma management in schools
Authors: Svavarsdottir Erla Kolbrun , Garwick Ann W. , Anderson Lori S. , Looman Wendy S. , Seppelt Ann , Orlygsdottir Brynja
Published: August 2012

Aim

This article is a report of an international study of barriers to asthma care from the perspectives of school nurses in Reykjavik, Iceland and St. Paul, Minnesota, in the context of their schools, communities and countries.

Background

Globally, asthma affects the health and school performance of many adolescents. School nurses play a key role by providing care to adolescents with asthma in school settings. Understanding universal barriers to asthma management in schools is important for developing interventions that are effective in multiple societal contexts.

Design

Exploratory, descriptive study.

Methods

Parallel studies were conducted from September 2008–January 2009, through six focus groups among school nurses (n = 32, in Reykjavikn = 17 and St. Pauln = 15) who were managing asthma in adolescents. Focus groups were audio‐recorded and transcribed verbatim in English or Icelandic. The Icelandic transcripts were translated into English. Descriptive content analytic techniques were used to systematically identify and categorize types of barriers to asthma care.

Results

School nurses in both countries identified common barriers, such as time constraints, communication challenges and school staff barriers. The primary difference was that St. Paul school nurses identified more socio‐economic and health access barriers than school nurses in Reykjavik.

Conclusion

Greater cultural and linguistic diversity and socio‐economic differences in the student population in St. Paul and lack of universal healthcare coverage in the US contributed to school nurses' need to focus more on asthma management than school nurses in Reykjavik, who were able to focus more on asthma prevention and education.
Psychometric properties of the Maslach Burnout Inventory for Human Services among Italian nurses: a test of alternative models
Authors: Pisanti Renato , Lombardo Caterina , Lucidi Fabio , Violani Cristiano , Lazzari David
Published: August 2012

Aim

The purpose of this study was to test the factor structure of an Italian version of the Maslach Burnout Inventory for Human Service employees. In addition we examined the reliability and construct validity of the scale.

Background

There is increasing evidence that nurses are at risk of experiencing burnout. Despite the vast international use of the Maslach Burnout Inventory‐Human Service Survey, its factor structure and reliability are not beyond question.

Method

In a sample of nurses (N = 1613) six alternative factor models of the instrument were tested using confirmatory factor analysis. Furthermore, we examined the invariance of the pattern of factor loadings of the model that better fitted the data across gender groups. To test construct validity, participants completed four subscales of Symptoms Check List 90‐R. Internal consistency was evaluated computing Cronbach's alpha estimates of the scales. The study was conducted in 2007 and 2008 in Italy.

Results

The factor analysis provided support for a 20‐item version identifying the three original dimensions. The model was found to be factorially invariant between men and women. Correlations between the latent MBI‐HSS dimensions and distress variables were in line with theoretical predictions. Reliability was supported by acceptable Cronbach's alpha indexes.

Conclusion

The Maslach Burnout Inventory‐Human Service Survey has acceptable validity and reliability for measuring burnout among nurses, and can help healthcare managers to offer interventions to reduce burnout among nurses. Limitations of the study and suggestions for further research are highlighted.
Optical tweezers: a light touch
Authors: LEE MICHAEL P. , PADGETT MILES J.
Published: August 2012

Optical tweezers use focused laser light to manipulate microscopic particles. We discuss the underlying physics of the technique in terms of a gradient force exerted by the light on the particles. The versatility of optical tweezers is highlighted, in particular, we explain how spatial light modulators and various imaging methods have greatly enhanced their range of applications.
Use of X‐ray micro tomography to study the microstructure of loose‐packed and compacted milk powders
Authors: CHAWANJI A.S. , BALDWIN A.J. , BRISSON G. , WEBSTER E.
Published: August 2012

The use of X‐rays to evaluate food microstructure has developed considerably in recent years. In this work we used X‐ray micro tomography (XMT) to visualize the microstructure of loose‐packed and compacted samples of spray‐dried skim milk powder (SMP) and whole milk powder (WMP) and to quantify the proportion of both interstitial and occluded air voids in each sample. Visual scrutiny of the acquired XMT images showed details of the microstructure of the milk powders such as the spherical morphology of the particles, the size of the particles and internal air voids of various sizes. Within loose‐packed powders, the proportion of air voids was higher (13% average) in WMP than in SMP. This was reversed in the compacted powders, in which the proportion of air voids was higher in SMP. The disparity in the proportion of air voids in both loose‐packed and compacted samples of SMP and WMP was attributed to the size, shape and surface properties of the particles.
Crystallographic structure of human tooth enamel by electron microscopy and x‐ray diffraction: hexagonal or monoclinic?
Authors: REYES‐GASGA J. , MARTÍNEZ‐PIÑEIRO E.L. , BRÈS É.F.
Published: August 2012

Recently reports on the major stability of the monoclinic phase of hydroxyapatite compared with the hexagonal phase have established it as the most observable structure of hydroxyapatite in natural materials, such as hard tissues. In this work, the structural and crystallographic analysis of the inorganic component of sound human tooth enamel was done by transmission electron microscopy, electron diffraction and X‐ray diffraction techniques. The results indicated that its unit cell is hexagonal not monoclinic.
Review: Genetics and neuropathology of primary pure dystonia
Authors: Paudel R. , Hardy J. , Revesz T. , Holton J. L. , Houlden H.
Published: August 2012

R. Paudel, J. Hardy, T. Revesz, J. L. Holton and H. Houlden (2012) Neuropathology and Applied Neurobiology38, 520–534

Genetics and neuropathology of primary pure dystonia

Neuropathology has been the key to understanding the aetiology of many neurological disorders such as Alzheimer's disease, Parkinson's disease, frontotemporal degeneration and cerebellar ataxias. Dystonia shares many clinical features with these conditions but research in general, has been unrewarding in providing information on disease processes. Neuropathological studies are few in number and only limited morphological abnormalities have been described. In the genetic literature, dystonia loci are represented as DYT and are assigned ascending numerals chronologically as they are identified. This review will concentrate on the neuropathology of primary pure dystonia, focusing on DYT1 and DYT6 and the correlation between clinical and genetic findings. Research in this area is incomplete and confounded by the rarity of post mortem brain tissue. However, recent findings, indicating a direct interaction between the torsinA (TOR1A) gene responsible for DYT1 and the thanatos‐associated domain‐containing apoptosis‐associated protein 1 (THAP1) gene responsible for DYT6, have important implications in understanding these two entities and also for other members of this group of disorders.