bluuebunny/crossref_metadata_2025 huggingface dataset:
Maturation of the liver‐specific peroxisome versus laminin, collagen IV and integrin expression
Authors: Depreter Marianne , Nardacci Roberta , Tytgat Tom , Espeel Marc , Stefanini Stefania , Roels Frank
Published: February 2012

The interaction of cells with extracellular matrix components contributes to their specific differentiation. We studied hepatic peroxisomes and their changing features during embryonic development, and we immunolocalized in the same tissue the extracellular matrix components laminin and collagen IV as well as the integrin receptor subunits α1, α2, β1 and β4. Rat and human embryonic liver peroxisome expression were studied at the light‐ and electron‐microscopic level by means of localizing catalase‐, D‐amino acid oxidase‐ and polyamine oxidase activities and by means of the immunocytochemistry of six peroxisomal proteins. The successive import of catalase and the peroxisomal β‐oxidation enzymes, the late appearance of the other enzymes, and the gradual increase of peroxisomal size and number to adult values occurred as asynchronous events. Although still immature, peroxisomes were recognized at every stage examined and coexisted with laminin and collagen IV in both species. The β1 integrin subunit was immunodetected as early as at 12.5 days in rat. It was concluded that these extracellular matrix factors may be important for the differentiation of liver parenchyma from the liverbud stage onwards. However, the stepwise maturation of the liver‐specific peroxisome suggests the involvement of many other regulating factors.
Changes in elongation factor‐1α transcripts are uncoupled to changes in EF‐1δ during sea urchin development
Authors: Delalande Christelle , Monnier Annabelle , Cormier Patrick , Mulner‐Lorillon Odile , Bellé Robert
Published: February 2012

A probe for Sphaerechinus granularis EF‐1α mRNA was generated and sequenced, and further used for comparative developmental analysis of gene expressions of two components of elongation factor‐1, EF‐1α and EF‐1δ. EF‐1α mRNA, detected as a single 2.7 kb transcript decreased 6 h after fertilization and dramatically increased 20 h post‐fertilization at the late blastula stage. The relative ratio of EF‐1α versus EF‐1δ transcripts varied from 0.2 up to 10 (× 50) during development, thus demonstrating uncoupling in the genetic expressions of the two EF‐1 components during the rapid cell divisions following fertilization and in the slow cell cycle period of later development.
Structural and immunohistological modifications in olfactory bulb of the staggerer mutant mouse
Authors: Monnier Zoré , Bahjaoui‐Bouhaddi Malika , Bride Jacqueline , Bride Michelle , Math François , Propper Alain
Published: February 2012

In the present study, we describe the structural and cytological changes observed in staggerer mutant olfactory bulbs, as compared to normal mice. On the basis of photonic and ultrastructural observations we tried to define the alterations induced by the mutation: ie a reduction of bulb size, a reduction in the volume of three out of the six architectonic layers (glomerular, external and internal plexiform), a reduction of glomeruli size, a loss of half the mitral cells and a slight decrease in juxtaglomerular interneuron number. In staggerer, an hypertrophy of glial ensheathing cell processes was especially evident at the level of each glomerulus, whereas the density of the astrocyte network was weaker in the granular layer and the nerve layer not apparently impaired. An immunofluorescent labelling study combined with confocal scanning microscopy was performed in order to identify the cellular type and the differentiation degree of the various elements. Antibodies anti‐GFAP, a protein present in both ensheathing cells and astrocytes, and anti‐OMP, the specific maturation protein of the nerve layer, were used for that purpose. Data confirmed the reality of the gliosis and the persistence of the sensory component in the mutant. All the structural alterations described in staggerer olfactory bulb were in close agreement with the functional troubles previously recorded. Our results are discussed in connection with the present knowledge on embryonal origin, fetal development and adult cellular renewal of the olfactory bulb.
Involvement of cGMP in cellular melatonin responses*
Authors: Bubis Marina , Zisapel Nava
Published: February 2012

Melatonin can enhance and suppress constitutive protein secretion from murine melanoma M2R cells in vitro in a cholera‐toxin (CTX) sensitive process. In a number of tissues melatonin has been shown to modulate cGMP levels. The involvement of cGMP in melatonin responses in the melanoma cells was investigated. The effects of melatonin on melanoma cells cGMP and cGMP‐phosphodiesterase activity and the effects of cGMP analogs on the melatonin‐mediated modulation of protein secretion were studied. Melatonin reduced cGMP levels in the melanoma cells. CTX treatment had a similar and non‐additive effect. The effects of melatonin on protein secretion were abrogated by activation of cGMP‐dependent protein kinases. In addition, melatonin inhibited cGMP phosphodiesterase activity in these cells. The data presented indicate that inhibition of cGMP via a CTX sensitive G protein may be a major signal transduction pathway used by melatonin in melanoma cells.
Microtubule organization by the budding yeast spindle pole body
Authors: Knop Michael , Pereira Gislene , Schiebel Elmar
Published: February 2012

In budding yeast microtubule organizing functions are provided by the spindle pole body (SPB), a multi‐layered structure that is embedded in the nuclear envelope throughout the cell cycle. The SPB organizes the nuclear and cytoplasmic microtubules which are spatially and functionally distinct. Microtubule formation in yeast requires the Tub4p‐complex, containing the γ‐tubulin Tub4p, and two additional proteins, the SPB components Spc97p and Spc98p. The Tub4p complex assembles in the cytoplasm and is then anchored to the sides of the SPB which organize microtubules. This is achieved by the binding of Spc97p and Spc98p to so‐called γ‐tubulin complex binding proteins (GTBPs) at the SPB. Spc72p is the yeast GTBP at the cytoplasmic side of the SPB, while Spc110p is the nuclear GTBP. Both GTBPs control the number of Tub4p complexes associated with the SPB and thereby the number of microtubules formed. In addition, the GTBPs may regulate the activity of the Tub4p complex. Homologues of Spc97p and Spc98p have been identified from yeast to mammalian cells and these are also part of γ‐tubulin complexes, suggesting that these related proteins may also interact with GTBPs at the centrosome. Candidates for GTBPs have been identified in mammalian and insect cells.
The centrosome cycle in syncytial Drosophila embryos analyzed by energy filtering transmission electron microscopy
Authors: Debec Alain , Marcaillou Christiane , Bobinnec Yves , Borot Caroline
Published: February 2012

We have investigated the centrosome cycle in Drosophila syncytial embryos at the ultrastructural level by using a transmission electron microscope equipped with an electron energy filtering device (Omega filter). This new technique allows the study of uncontrasted thick sections with a high resolution. We have been able to characterize two classes of filamentous structures in the centrosomal apparatus that were not detectable on ultrathin sections. These new filamentous structures are: 1) a very orderly lattice that connects the two centrioles during mitosis; and 2) a fibrogranular connection between the centrosome and the nuclear envelope. The intercentriolar linkage could be involved in the precise timing of separation of the centrioles during late anaphase. The centrosome‐nuclear envelope connection probably prevents the loss of centrosomes in this syncytial environment, and ensures the proper migration of the centrosomes along the surface of the nucleus. This connection may also couple the nuclei to the cytoskeleton, thus allowing their migration and their anchorage to the cortex at the blastoderm stage. This thick section analysis has also allowed us to precisely reconstitute the centrosome cycle. From their separation at telophase and throughout most of interphase, centrosomes are composed of a single centriole. We conclude that in the early Drosophila embryo there is an unusual delay between the separation of the parent centrioles and their duplication. This leaves a surprisingly short time to assemble a daughter centriole.
Transient reactivation of CSF in parthenogenetic one‐cell mouse embryos
Authors: Ciemerych Maria A , Kubiak Jacek Z
Published: February 2012

During meiosis, the cytostatic factor (CSF) activity stabilizes the activity of the M‐phase promoting factor (MPF) in metaphase II arrested vertebrate oocytes. Upon oocyte activation, the inactivation of both MPF and CSF enables the entry into the first embryonic mitotic cell cycle. Using a biological assay based on cell‐fusion (hybrid between a parthenogenetically activated egg entering the first mitotic division and an activated oocyte), we observed that in activated mouse oocytes a first drop in CSF activity is detectable as early as 20 min post‐activation. This suggests that CSF is inactivated upon MPF inactivation. However, CSF activity increases again to reach a maximum 60 min post‐activation and gradually disappears during the following 40 min. Thus, in activated mouse oocytes (undergoing the transition to interphase) CSF activity fluctuates before definitive inactivation. We found that hybrids arrested in M‐phase, thus containing CSF activity after oocyte activation, have activated forms of MAP kinases while hybrids in interphase have inactive forms of these enzymes. We postulate that CSF inactivation in mouse oocytes proceeds in two steps. The initial inactivation of CSF, required for MPF inactivation, is transient and does not require MAP kinase inactivation. The final inactivation of CSF, required for normal embryonic cell cycle progression, is dependent upon the inactivation of MAP kinases.
The Saccharomyces cerevisiae Cdc14 phosphatase is implicated in the structural organization of the nucleolus
Authors: de Almeida Annabelle , Raccurt Ingrid , Peyrol Simone , Charbonneau Michel
Published: February 2012

Cdc14, a dual‐specificity protein phosphatase, has been previously implicated in triggering exit from mitosis in the yeast Saccharomyces cerevisiae. Using immunofluorescence microscopy and immunogold labeling, we demonstrate that a functional HA‐tagged version of the phosphatase Cdc14 localizes to the nucleolus. Moreover, Cdc14‐HA co‐localized with the nucleolar NOP2 and GAR1 proteins. By immunofluorescence, Cdc14‐HA was found in the nucleolus during most of the mitotic cell cycle, except during anaphase‐telophase when it redistributed along the mitotic spindle. While this work was in progress, the same pattern of Cdc14 localization was described by others (Visintin et al, Nature 398 (1999) 818). Constitutive overexpression of CDC14 was toxic and led to cell cycle arrest of cells, mainly in G1. This correlated with the appearance of abnormal nuclear structures. A genetic search for suppressors of the lethality associated with CDC14 overexpression identified YJL076W. Because overproduction of Yj1076w buffered the toxic effect of Cdc14 overproduction, this suggested that it might be a substrate of Cdc14. This has indeed been found to be the case by others who recently described Yj1076w Net1 as a nucleolar protein that physically associates with Cdc14 (Shou et al, Cell 97 (1999) 233). The present data confirm several recently uncovered aspects of the regulation of Cdc14 localization and activity and suggest that the level of expression of CDC14 influences the structural organization of the nucleolus.
Dynamics of glial fibrillary acidic protein distribution in cultured glomerular podocytes and mesangial cells of the rat kidney
Authors: Buniatian Gayane , Gebhardt Rolf , Traub Peter , Mecke Dieter , Osswald Hartmut
Published: February 2012

Glial fibrillary acidic protein (GFAP) has recently been shown to be expressed in the glomerular podocytes and mesangial cells (MC) of kidney (Buniatian et al (1998) Biol Cell 90, 53–61). The different localization of GFAP in podocytes and MC has raised the question whether this might reflect specific cellular functions. To address this question, in the present study podocytes and MC in early (2, 3 day‐old), prolonged (5, 7 day‐old) and late (14, 21 day‐old) primary cultures from out‐growths of glomerular explants were used. Double‐immunolabeling studies demonstrated that podocytes transiently acquire myofibroblastic features, characterized by the expression of smooth muscle alpha‐actin (SMAA) and increased perinuclear reaction of GFAP in prolonged cultures. The morphological differentiation of cobblestone‐like podocytes into process‐bearing cells was followed by loss of the myofibroblastic marker, SMAA, de novo expression of desmin, and distribution of GFAP, vimentin and desmin into the processes. In late culture, GFAP and SMAA were nearly absent from the podocytes which maintained the cobblestone‐like morphology. By contrast, the myofibroblastic features gained by MC during prolonged culturing increased with time. A myofibroblast‐like cytoskeleton of podocytes and MC similar to that of healthy astrocytes suggests an increased spectrum of functional activities of these cells during the acquisition of myofibroblastic features. In addition, the present study provides a new combination of biochemical and biological features by which podocytes and MC can be distinguished in culture.
Rat arylalkylamine N‐acetyltransferase gene: Upstream and intronic components of a bipartite promoter
Authors: Baler Ruben , Covington Simmons , Klein David C
Published: February 2012

The daily rhythm in the activity of arylalkylamine N‐acetyltransferase (AA‐NAT) controls the rhythm in melatonin synthesis in the pineal gland. In the rat, transcriptional regulatory mechanisms play a major role in determining the observed pattern of AA‐NAT gene expression. Remarkably, high levels of AA‐NAT transcripts can only be detected in the night pineal; significant levels can also be found in the retina. To characterize the regulatory events that impinge upon the activity of the AA‐NAT gene we embarked on the systematic analysis of the AA‐NAT promoter. To this end we transfected several AA‐NAT promoter derivative constructs to monitor reporter gene activity in both pineal and non‐pineal primary cell cultures. Our studies revealed a cooperative arrangement between upstream promoter and downstream intronic regions which appear to contain most of the key elements necessary to ensure the proper spatio‐temporal pattern of AA‐NAT gene expression.
Concentrations of Plasma Metabolites, Hormones, and mRNA Abundance of Adipose Leptin and Hormone‐Sensitive Lipase in Ketotic and Nonketotic Dairy Cows
Authors: Xia C. , Wang Z. , Xu C. , Zhang H.Y.
Published: February 2012

Background

Ketosis is an important metabolic disorder of dairy cows during the transition period. There have been many reports on the etiology of ketosis in periparturient cows, but little is known about its molecular etiology.

Objectives

The objective of this study was to clarify the status of fat mobilization and mRNA abundance of leptin and hormone‐sensitive lipase in cows with spontaneous clinical ketosis.

Animals

Ten ketotic Holstein cows and 10 nonketotic Holstein cows were used as the experimental animals.

Methods

Six blood biochemical parameters were evaluated by means of individual analysis method for 2 groups of cows. The mRNA abundance of leptin and hormone‐sensitive lipase in tail fat tissue from 2 groups of cows was measured by real‐time (RT)‐PCR, with a fluorescent Taqman probe and a standard curve.

Results

The plasma concentrations of glucose (P = 0.01), and leptin (P = 0.03), insulin (P = 0.05), and the ratio of insulin to glucagon (P = 0.04) were lower in ketotic compared with nonketotic cows, whereas there were marked increases in the plasma concentrations of nonesterified fatty acid and β‐hydroxybutyric acid (P = 0.005). The mRNA abundance of leptin (P = 0.04) and hormone‐sensitive lipase (P = 0.02) in the fat tissue of ketotic cows was lower relative to that of nonketotic cows.

Conclusions and Clinical Importance

The ketotic cows showed characteristics of type I ketosis and some adaptive changes to negative energy balance in the plasma leptin concentration and mRNA abundance of fat leptin and hormone‐sensitive lipase.
The Use of Darbepoetin to Stimulate Erythropoiesis in Anemia of Chronic Kidney Disease in Cats: 25 Cases
Authors: Chalhoub S. , Langston C.E. , Farrelly J.
Published: February 2012

Background

Anemia is present in 30–65% in cats with chronic kidney disease (CKD) and few long‐term treatment options exist. Darbepoetin is effective in treating anemia of kidney disease in humans and may be used in cats.

Hypothesis/Objective

To evaluate the use of darbepoetin, a recombinant analog of human erythropoietin, to stimulate erythropoiesis, and to effectively treat anemia of kidney disease in cats.

Animals

Twenty‐five of 66 cats that received ≥2 doses of darbepoetin at theAnimalMedicalCenter between January 2005 and December 2009 were included in this study.

Methods

Cats were included in the study if they received darbepoetin and follow‐up data were available for at least 56 days and hadCKDas a primary clinical diagnosis. Cats were excluded if they were treated with darbepoetin but did not have kidney disease. Response to treatment was defined as reaching or exceeding a target packed red blood cell volume or hematocrit of 25%.

Results

Fourteen of 25 cats responded. Thirteen of those 14 cats received a dosage of 1 μg/kg/wk or higher. Presumptive adverse effects included vomiting, hypertension, seizures, and fever.

Conclusions and Clinical Relevance

Darbepoetin is effective for treatment of anemia of kidney disease in cats. Pure red cell aplasia appears to be less common with darbepoetin than with epoetin usage.
Evaluation of Levetiracetam as Adjunctive Treatment for Refractory Canine Epilepsy: A Randomized, Placebo‐Controlled, Crossover Trial
Authors: Muñana K.R. , Thomas W.B. , Inzana K.D. , Nettifee‐Osborne J.A. , McLucas K.J. , Olby N.J. , Mariani C.J. , Early P.J.
Published: February 2012

Background

There is little evidence‐based information available to guide treatment of refractory epilepsy in dogs. The antiepileptic drug levetiracetam (LEV) is administered to dogs, although its safety and efficacy are unknown.

Objective

To evaluate the safety and efficacy of LEV as adjunctive therapy for refractory epilepsy in dogs.

Animals

Thirty‐four client‐owned dogs with idiopathic epilepsy.

Methods

Randomized, blinded trial involving dogs resistant to phenobarbital and bromide. Dogs received LEV (20 mg/kg PO q8h) or placebo for 16 weeks, and after a 4‐week washout were crossed over to the alternate treatment for 16 weeks. Owners kept records on seizure frequency and adverse events. Hemogram, chemistry profile, urinalysis, and serum antiepileptic drug concentrations were evaluated at established intervals.

Results

Twenty‐two (65%) dogs completed the study. Weekly seizure frequency during the 1st treatment period decreased significantly during LEV administration relative to baseline (1.9 ± 1.9 to 1.1 ± 1.3, P = .015). The reduction in seizures with LEV was not significant when compared to placebo (1.1 ± 1.3 versus 1.5 ± 1.7, P = .310). The most common adverse event was ataxia, with no difference in incidence between LEV and placebo (45 versus 18%, P = .090). No changes in laboratory parameters were identified and owners reported an improved quality of life (QOL) with LEV compared to placebo (QOL score 32.7 ± 4.3 versus 29.4 ± 4.5, P = .028).

Conclusions and Clinical Importance

Adjunctive treatment with LEV appears safe in epileptic dogs. Efficacy of LEV over placebo was not demonstrated, although the power of the study was limited. Further evaluation of LEV as treatment for epilepsy in dogs is warranted.
What Do Middle and High School Students Know About the Particulate Nature of Matter After Instruction? Implications for Practice
Authors: Aydeniz Mehmet , Kotowski Erin Leigh
Published: February 2012

This study explores middle and high school students' understanding of the particulate nature of matter after they were taught the concept. A total of 87 students (41 high school and 46 middle school) participated in the study. Findings suggest that students held misconceptions about the law of conservation of matter, chemical composition of matter in different phases of matter, the process of condensation, and behaviors of molecules at a microscopic level. The discussion focuses on the implications of these findings for enhancing science teachers' pedagogical content knowledge.
Students' Perceptions of Single‐Gender Science and Mathematics Classroom Experiences
Authors: Brown Sherri L. , Ronau Robert R.
Published: February 2012

While participating in single‐ and mixed‐gender science and mathematics classes, ninth‐grade urban high school students' (n= 118) academic self‐concept, self‐efficacy, and school climate perceptions were examined. Their perceptions were measured quantitatively from the Fennema‐Sherman Mathematics (modified for Science) Attitude and the Patterns of Adaptive Learning scales. Five factors arose from each instrument: confidence/efficacy, utility, instruction, climate, and anxiety/performance avoidance. Comparative factor analysis of the science‐modified Fennema‐Sherman Scale showed similar constructs within the mathematics scale. Our findings are congruent with reports concerning single‐gender classrooms that find few significant differences in students' attitudes toward science and mathematics, or classroom climate, with regard to single‐gender classes. Lastly, our results supported three structural equation models for the hypothesized factors from each instrument.
Identification of Error Types in Preservice Teachers' Attempts to Create Fraction Story Problems for Specified Operations
Authors: McAllister Cheryl J. , Beaver Cheryl
Published: February 2012

The purpose of this research was to determine if recognizable error types exist in the work of preservice teachers required to create story problems for specific fraction operations. Students were given a particular single‐operation fraction expression and asked to do the calculation and then create a story problem that would require the use of both the expression and calculation to answer the story problem. Distinct error types, determined by mathematical and grammatical characteristics, were identified by the researchers. These error types were then used to analyze an additional set of work samples to determine frequency rates of error types. Future research will involve evaluating the efficacy of specific instructional methods with the goal of reducing the frequency of certain error types.
Men behaving nicely: Public goods as peacock tails
Authors: Van Vugt Mark , Iredale Wendy
Published: February 2012

Insights from sexual selection and costly signalling theory suggest that competition for females underlies men's public good contributions. We conducted two public good experiments to test this hypothesis. First, we found that men contributed more in the presence of an opposite sex audience, but there was no parallel effect for the women. In addition, men's public good contributions went up as they rated the female observer more attractive. In the second experiment, all male groups played a five round public good game and their contributions significantly increased over time with a female audience only. In this condition men also volunteered more time for various charitable causes. These findings support the idea that men compete with each other by creating public goods to impress women. Thus, a public good is the human equivalent of a peacock's tail.
Shifting curves? Trends in thinness and obesity among Australian youth, 1985 to 2010
Authors: Hardy L. L. , Cosgrove C. , King L. , Venugopal K. , Baur L. A. , Gill T.
Published: February 2012

Objective

To describe 25‐year trends in the prevalence of ≤Grade 2 thinness and obesity among Australian children by sex, age and socioeconomic (SES) background.

Methods

Cross‐sectional surveys of New South Wales school‐aged children aged 6.0–16.9 years conducted in 1985–1997–2004–2010 (n = 19 434). Height/weight were measured, and thinness and obesity were defined by international standards. SES was derived from children's residential postcode using the Australian Bureau of Statistics' Index of Relative Socioeconomic Disadvantage, most proximal to the survey year.

Results

Since 1985, the prevalence of thinness has not varied by survey year. Age was not associated with thinness; however, thinness was lower among middle SES boys, compared with high SES (OR: 0.45, 95%CI: 0.21, 0.97). The prevalence of obesity trebled between 1985 and 1997 (1.7% vs. 5.1% P = 0.000); however, since 1997, obesity prevalence has not significantly changed. Since 1997, obesity was higher among younger compared with older girls (OR: 2.11, 95%CI: 1.48, 3.00) and SES was inversely associated with obesity in boys (OR: 2.05, 95%CI: 1.44, 2.92) and girls (OR: 1.86, 95%CI: 1.27, 2.74).

Conclusions

The apparent plateau in child obesity is a welcome finding; however, the SES gradients are of concern. If the obesity stabilization is associated with the impact of multiple lifestyle behavioural interventions, the findings suggest obesity programmes have done ‘no harm’, but potentially the dose/delivery of interventions has not been sufficient or appropriate to reduce child obesity levels.
Experimental Analysis of Confined Jet Flames by Laser Measurement Techniques
Authors: Lammel Oliver , Stöhr Michael , Kutne Peter , Dem Claudiu , Meier Wolfgang , Aigner Manfred
Published: February 2012

An experimental analysis of confined premixed turbulent methane/air and hydrogen/air jet flames is presented. A generic lab scale burner for high-velocity preheated jets equipped with an optical combustion chamber was designed and set up. The size and operating conditions were configured to enable flame stabilization by recirculation of hot combustion products. The geometry of the rectangular confinement and an off-center positioning of the jet nozzle were chosen to resemble one burner nozzle of a FLOX®-based combustor. The off-center jet arrangement caused the formation of a pronounced lateral recirculation zone similar to the one in previously investigated FLOX®-combustors (Lückerath et al., 2007. “FLOX® Combustion at High Pressure with Different Fuel Compositions,” ASME J. Eng. Gas Turbines Power, 130(1), pp. 011505; Lammel et al., 2010. “FLOX® Combustion at High Power Density and High Flame Temperatures,” ASME J. Eng. Gas Turbines Power, 132(12), p. 121503ff). The analysis was accomplished by different laser measurement techniques. Flame structures were visualized by OH* chemiluminescence imaging and planar laser-induced fluorescence of the OH radical. Laser Raman scattering was used to determine concentrations of the major species and the temperature. Velocity fields were measured with particle image velocimetry. Results of measurements in two confined jet flames are shown. The mixing of fresh gas with recirculating combustion products and the stabilization of the methane flame are discussed in detail. The presented findings deliver important information for the understanding of confined jet flames operated with different fuels. The obtained data sets can be used for the validation of numerical simulations as well.
Eddy Current Damper for Turbine Blading: Electromagnetic Finite Element Analysis and Measurement Results
Authors: Laborenz Jacob , Krack Malte , Panning Lars , Wallaschek Jörg , Denk Markus , Masserey Pierre-Alain
Published: February 2012

In the dynamics of turbomachinery, the mechanical damping of the blading has been the focus of research for the last decades to improve the dynamic performance in terms of high cycle fatigue issues. In addition, an increased mechanical damping can produce a higher flutter safety margin such that stable operation conditions are achievable in a bigger range. Hence, novel damping techniques are considered besides the well known friction based damping devices. In this paper, an extended analysis of the eddy current based damping device for a last stage steam turbine blading presented in GT2009-59593 is conducted. A transient electromagnetic finite element analysis of the eddy current damper is performed, and the resulting damping forces are compared to their analytical solution. Parameter studies are carried out, and equivalent damping factors are calculated. Furthermore, for the validation of the finite element model, a test rig was built that allows for the direct measurement of damping forces when forcing a sinusoidal relative motion. Forced response measurements and simulations are used to demonstrate its dynamic performance and predictability.
Experimental Investigation of Invar Edge Effect in Membrane LNG Tanks
Authors: Graczyk Mateusz , Berget Kjetil , Allers Joachim
Published: February 2012

Sloshing, a violent fluid motion in tanks is of current interest for many branches of the industry, among them gas shipping. Although different methods are commonly combined for analyzing sloshing in liquid natural gas (LNG) carriers, time histories of the pressure in the tanks are most reliably obtained by experiments. Very localized pressures may be important for the structural response of the tank containment system. Moreover, the typical pressure time history duration is similar to the structural natural frequency. Therefore, pressure measurements need to be performed with due account for temporal and spatial distribution. This requires a high sampling resolution both in time and space. Fine spatial resolution becomes especially important when local pressure effects are of interest, such as pressure profile passing a membrane corrugation of Mark III containment or Invar edge of No. 96 containment. In this paper experimental approach applied by MARINTEK for analyzing sloshing phenomenon is presented. The focus is put on investigating effects of Invar edges. A transverse 2D model of a typical LNG carrier is used. Local pressure effects are investigated based on low filling level tests with different wall surfaces: smooth and with horizontal protrusions representing the surface similar to the No. 96 containment system.
Syrinx Fluid Transport: Modeling Pressure-Wave-Induced Flux Across the Spinal Pial Membrane
Authors: Elliott N. S. J.
Published: February 2012

Syrinxes are fluid-filled cavities of the spinal cord that characterize syringomyelia, a disease involving neurological damage. Their formation and expansion is poorly understood, which has hindered successful treatment. Syrinx cavities are hydraulically connected with the spinal subarachnoid space (SSS) enveloping the spinal cord via the cord interstitium and the network of perivascular spaces (PVSs), which surround blood vessels penetrating the pial membrane that is adherent to the cord surface. Since the spinal canal supports pressure wave propagation, it has been hypothesized that wave-induced fluid exchange across the pial membrane may play a role in syrinx filling. To investigate this conjecture a pair of one-dimensional (1-d) analytical models were developed from classical elastic tube theory coupled with Darcy’s law for either perivascular or interstitial flow. The results show that transpial flux serves as a mechanism for damping pressure waves by alleviating hoop stress in the pial membrane. The timescale ratio over which viscous and inertial forces compete was explicitly determined, which predicts that dilated PVS, SSS flow obstructions, and a stiffer and thicker pial membrane—all associated with syringomyelia—will increase transpial flux and retard wave travel. It was also revealed that the propagation of a pressure wave is aided by a less-permeable pial membrane and, in contrast, by a more-permeable spinal cord. This is the first modeling of the spinal canal to include both pressure-wave propagation along the spinal axis and a pathway for fluid to enter and leave the cord, which provides an analytical foundation from which to approach the full poroelastic problem.
InAs MOS devices passivated with molecular beam epitaxy-grown Gd2O3 dielectrics
Authors: Lin C. A. , Huang M. L. , Chiu P.-C. , Lin H.-K. , Chyi J.-I. , Chiang T. H. , Lee W. C. , Chang Y. C. , Chang Y. H. , Brown G. J. , Kwo J. , Hong M.
Published: February 2012

InAs MOS devices passivated with molecular beam epitaxy (MBE)-grown Gd2O3 2–3 monolayers thick followed by an Al2O3 cap have demonstrated excellent electrical performances and interfacial properties. Band offset energies of in situ atomic-layer-deposited (ALD)-Al2O3/MBE-Gd2O3/InAs and ALD-Al2O3/InAs were determined by in situ x-ray photoelectron spectroscopy in conjunction with Fowler–Nordheim tunneling current analysis. A conduction-band offset energy (ΔEc) and a valence-band offset energy of 2.3 and 3.92 eV for ALD-Al2O3/InAs were determined, respectively. The insertion of a Gd2O3 layer increases the value of ΔEc by nearly 0.1 eV as compared to the case for Al2O3 directly deposited on InAs. The distribution of interfacial density of states (Dit) within the InAs bandgap, deduced by the conductance method at 77 K, gives a low Dit value of 1012 cm−2 eV−1 near the conduction-band edge. Moreover, with energy band engineering in the heterostructure, gate-first depletion channel InAs MOSFETs have produced drain current density of 46 μA/μm and transconductance of 17 μS/μm for 12-μm-gate-length devices at 300 K.
Molecular beam epitaxy growth of AlGaN quantum wells on 6H-SiC substrates with high internal quantum efficiency
Authors: Zhang Wei , Nikiforov A. Yu. , Thomidis C. , Woodward J. , Sun H. , Kao Chen-Kai , Bhattarai D. , Moldawer A. , Zhou L. , Smith D. J. , Moustakas T. D.
Published: February 2012

The authors report the development of high internal quantum efficiency AlN/AlGaN/AlN double heterostructures and AlGaN/AlN multiple quantum wells (MQWs) grown on 6H-SiC and 4H-SiC substrates of various miscuts by plasma-assisted molecular-beam epitaxy. The authors find that the luminescence spectra for identical MQWs show a single peak across the gap, with a wavelength that is redshifted by ∼20 nm as the excess Ga during growth of the wells increases. The internal quantum efficiency of the double heterostructures emitting at 250 nm is found to be 43%, and that of the multiple quantum wells emitting at 245 nm is 68%. These results suggest that AlGaN alloys on SiC substrates are capable of producing deep-ultraviolet emitters with high efficiency. The authors propose that these results can be accounted for by the introduction of lateral band structure potential fluctuations due to the changing of the growth mode from physical vapor phase epitaxy to liquid phase epitaxy (LPE) as the excess gallium increases. In this LPE mode the arriving active nitrogen species from the plasma source and aluminum atoms from the aluminum effusion cells dissolve in the excess liquid gallium and incorporate into the film from the liquid phase.
Characteristic comparison of AlGaN/GaN enhancement-mode HEMTs with CHF3 and CF4 surface treatment
Authors: Chen C. H. , Yang C. W. , Chiu H. C. , Fu Jeffrey. S.
Published: February 2012

In this study, enhancement-mode (E-mode) AlGaN/GaN HEMTs that underwent CHF3 and CF4 plasma treatment beneath the gate metal were fabricated. These treatments were applied because, although previous studies have formed AlF3 compound layers after fluorine-based plasma treatment to suppress the polarization-induced charge density, the surface negative charges still influenced the device gate leakage current and trap density. In the device in this study, unlike in previous CF4 plasma-treated GaN E-mode devices, the hydrogen atoms of the CHF3 plasma were introduced to compensate for vacancies by donating an electron to a vacancy acceptor level, thereby reducing the number of vacancy induced traps. Based on the measured subthreshold slope (SS) and the effective interface state density (Dit) results, the SS value of a CHF3-treated HEMT was 80 mV/decade and the Dit was 1.23 × 1012 cm−2. Moreover, the CHF3-treated HEMT exhibited a current gain cut-off frequency, a maximum oscillation frequency, and an output power of 6.7, 26, and 14.8 dBm (302 mW/mm), respectively. The 1/f noise measurement results of the CHF3-treated HEMT indicated that the flicker noise-induced generation-recombination noise and gate leakage-induced generation-recombination noise were also improved. Therefore, the CHF3-treated HEMT has great potential for use in low-distortion power amplifiers and logic control circuits.
Emission properties of carbon nanowalls on porous silicon
Authors: Evlashin Stanislav A. , Mankelevich Yuri A. , Borisov Vladimir V. , Pilevskii Andrey A. , Stepanov Anton S. , Krivchenko Victor A. , Suetin Nikolai V. , Rakhimov Alexander T.
Published: February 2012

For the past two decades various methods of carbon nanostructures growth have been proposed. Special substrate pretreatment methods are generally used to grow carbon nanowalls on silicon substrates and among them are mechanical and catalytic methods and ion bombardment in an rf discharge with bias. This work describes the possibility of growing carbon structures on porous silicon in a dc discharge without any additional pretreatment of the substrate surface. Carbon structures were grown on n- and p-type (100) porous silicon substrates produced by using standard photoelectrochemical etching. The analysis of these carbon structures revealed nanocrystalline carbon with multilayer carbon nanotubes and fibers. All samples demonstrated low field emission thresholds (Etr < 3 V/μm) and high current densities, showing an achieved current density of more than 6 A/cm2 for an electric field of E ∼ 15 V/μm. The authors investigated various modifications of porous silicon samples and carbon structures and demonstrated a practicable technique to create a reproducible uniform spot that varies in size from several millimeters to tens of millimeters. The authors propose a simplified and less expensive alternative to existing methods.
Adaptations of Avian Flu Virus Are a Cause for Concern
Authors: Berns Kenneth I. , Casadevall Arturo , Cohen Murray L. , Ehrlich Susan A. , Enquist Lynn W. , Fitch J. Patrick , Franz David R. , Fraser-Liggett Claire M. , Grant Christine M. , Imperiale Michael J. , Kanabrocki Joseph , Keim Paul S. , Lemon Stanley M. , Levy Stuart B. , Lumpkin John R. , Miller Jeffery F. , Murch Randall , Nance Mark E. , Osterholm Michael T. , Relman David A. , Roth James A. , Vidaver Anne K.
Published: February 2012

Members of the National Science Advisory Board for Biosecurity explain its recommendations on the communication of experimental work on H5N1 influenza.
Meaningful Use of Electronic Behavioral Health Data in Primary Health Care
Authors: Tai Betty , Boyle Maureen , Ghitza Udi , Kaplan Robert M. , Clark H. Westley , Gersing Kenneth
Published: February 2012

Increased demands for the treatment of mental health and substance abuse conditions will require the delivery of services through an integrated system based in primary care.
The Anti-Trypanosome Drug Fexinidazole Shows Potential for Treating Visceral Leishmaniasis
Authors: Wyllie Susan , Patterson Stephen , Stojanovski Laste , Simeons Frederick R. C. , Norval Suzanne , Kime Robert , Read Kevin D. , Fairlamb Alan H.
Published: February 2012

Fexinidazole, a drug in clinical testing for African sleeping sickness, shows potential as an oral treatment for another neglected tropical disease.
Allergic to the Cold
Authors: Niewold Timothy B.
Published: February 2012

Mutations in the
PLCG2
gene cause an inflammatory disease triggered by cold temperature.
Science Should Be in the Public Domain
Authors: Racaniello Vincent R.
Published: February 2012

Variants of avian influenza H5N1 virus that are transmitted by the airborne route among ferrets have been identified. The National Science Advisory Board for Biosecurity has advised against publication of the details of the methods used to obtain these viruses and the amino acid changes that lead to transmission in ferrets. This decision is not based on sound scientific principles and risks setting a precedent that will make it easier to put in place highly restrictive regulations on scientific research and publication.
The NSABB Recommendations: Rationale, Impact, and Implications
Authors: Keim Paul S.
Published: February 2012

The National Science Advisory Board for Biosecurity (NSABB) has recommended that two scientific papers concerning the laboratory adaptation of avian H5N1 influenza virus to mammal-to-mammal respiratory transmission restrict their content to prevent others from replicating their work. After hearing from experts in the field of influenza research and public health, the benefits of the research were deemed less important than the potential negative consequences. The evaluation followed established NSABB procedures and prior policy recommendations for identifying dual use research of concern (DURC). This recommendation was received by the United States Government, endorsed and forwarded to the research teams and scientific journals involved with the publications.
Application of the UK NHS Improvement Anticoagulation Commissioning Support Document for ‘safety indicators’ in atrial fibrillation. Results of the European Action on Anticoagulation study
Authors: Poller Leon , Jespersen Jørgen , Cowan Campbell , Baglin Trevor , George Jennifer , Ibrahim Saied A
Published: February 2012

Introduction

'Safety indicators' in the anticoagulant management of atrial fibrillation (AF) are listed in the UK NHS Improvement Document, ‘Anticoagulation for AF’, aiming to promote quality services. Acceptable clinical event rates are not quantified in the document.

Objective

To provide clinical evaluation of the relevant safety indicators using data from a recent large European Action on Anticoagulation (EAA) study.

Results

469 clinical events were recorded in 5839 outpatients in the EAA study. The safety indicators listed in the NHS Improvement Document were related to these patients with AF. The relevance of the ‘safety indicators’ is confirmed by the EAA study for patients starting oral anticoagulation and for those already receiving oral anticoagulation, and quantified.

Conclusion

The EAA clinical study provides a quantitative basis for the safety indicators' in AF listed in the NHS Commissioning Support Document and emphasises the importance of the document.
ORBITALLY EXCITED STATES OF QUARKONIA IN A NONRELATIVISTIC MODEL
Authors: BHAGHYESH  , VIJAYA KUMAR K. B. , MA YONG-LIANG
Published: February 2012

Having succeeded in predicting the S wave spectra and decays of [Formula: see text] and [Formula: see text] mesons, Bhaghyesh, K. B. Vijaya Kumar and A. P. Monteiro, J. Phys. G: Nucl. Part. Phys.38, 085001 (2011), in this article, we apply our nonrelativistic quark model to calculate the spectra and decays of the orbitally excited states (P- and D-waves) of heavy quarkonia. The full [Formula: see text] potential used in our model consists of a Hulthen potential and a confining linear potential. The spin hyperfine, spin-orbit and tensor interactions are introduced to obtain the masses of the P- and D-wave states. The three-dimensional harmonic oscillator wave function is employed as a trial wave function to obtain the mass spectra. The model parameters and the wave function that reproduce the mass spectra of [Formula: see text] and [Formula: see text] mesons are used to investigate their decay properties. The two-photon decay widths, two-gluon decay widths and E1 radiative decay widths are calculated. The obtained values are compared with the experimental results and those obtained from other theoretical models.
AUTOMATIC GENERATION OF CROSSWORD PUZZLES
Authors: RIGUTINI LEONARDO , DILIGENTI MICHELANGELO , MAGGINI MARCO , GORI MARCO
Published: February 2012

Crossword puzzles are used everyday by millions of people for entertainment, but have applications also in educational and rehabilitation contexts. Unfortunately, the generation of ad-hoc puzzles, especially on specific subjects, typically requires a great deal of human expert work. This paper presents the architecture of WebCrow-generation, a system that is able to generate crosswords with no human intervention, including clue generation and crossword compilation. In particular, the proposed system crawls information sources on the Web, extracts definitions from the downloaded pages using state-of-the-art natural language processing techniques and, finally, compiles the crossword schema with the extracted definitions by constraint satisfaction programming. The system has been tested on the creation of Italian crosswords, but the extensive use of machine learning makes the system easily portable to other languages.
PHOTOINDUCED BENDING UPON PULSED IRRADIATION IN AZOBENZENE-CONTAINING CROSSLINKED LIQUID-CRYSTALLINE POLYMERS
Authors: SHIMAMURA AKI , PRIIMAGI ARRI , MAMIYA JUN-ICHI , KINOSHITA MOTOI , IKEDA TOMIKI , SHISHIDO ATSUSHI
Published: February 2012

We have investigated the photoresponsive behavior of homogeneously aligned low-azobenzene-concentration crosslinked liquid-crystalline polymers. We compared the thermal contraction and photocontraction of the films, and show that upon UV irradiation, they bend efficiently towards the actinic light source. The photoinduced bending is studied both under continuous-wave irradiation and irradiation with nanosecond pulses. Pulsed irradiation revealed that the photomechanical response can take place within sub-millisecond time scale, and that even a single laser pulse can cause the sample to bend.
POLARIZATION-CONTROLLABLE WINGED NANOCONE TIP ANTENNA
Authors: HUTTUNEN MIKKO J. , MÄKITALO JOUNI , KAURANEN MARTTI
Published: February 2012

We propose winged metal nanocone optical antennas for efficient coupling of far-field radiation into the near-field of sharp metal tips. Unlike normal sharp metal tips, the winged nanocones require no oscillating field along the tip axis for the excitation of the tips. We calculate extinction spectra and local-field enhancements for single and winged gold nanocones and show that the field enhancements in the tips of the winged cones are due to a combination of particle plasmon resonances and a lightning-rod effect. We also propose that the winged nanocones could be used for optical far-field background suppression for tip-enhanced microscopy.
DUAL WAVELENGTH HIGH POWER DOUBLE-CLAD ERBIUM/YTTERBIUM-DOPED FIBER LASER
Authors: MOGHADDAM M. R. A. , HARUN S. W. , SHAHI S. , AHMAD H.
Published: February 2012

A dual wavelength high power double-clad erbium/ytterbium-doped fiber laser with a narrowest spacing of 0.4 nm and a M2 value of close to unity is presented in the region of 1565 nm. This result can be realized with a significant improvement of the mode competition problem using a loop mirror as a comb filter. The wavelength region can also be varied using polarization controllers in the loop mirror. This dual-wavelength fiber laser with side mode suppression ratio (SMSR) of 40 dB is quite stable, and the output power variance is as low as 0.46 dB.
SINGLE DOMAIN WALL EFFECT ON PARAMETRIC PROCESSES VIA CHERENKOV-TYPE PHASE MATCHING
Authors: REN HUAIJIN , DENG XUEWEI , ZHENG YUANLIN , CHEN XIANFENG
Published: February 2012

We report on a new character of single domain wall (DW) of electrically-poled ferroelectric crystal which can modulate parametric processes via Cherenkov-type phase matching. Experimental result shows that the effective nonlinear polarization is confined in DW, and its phase velocity can be modulated when incident light is off the domain wall's direction. These effects lead to novel Cherenkov second harmonic generation (CSHG), and other modulated parametric process, such as Cherenkov sum frequency generation (CSFG).