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Sample records for laktierenden ratten vpt

  1. Transition metal complexes of Vanillin- 4N-(2-pyridyl) thiosemicarbazone (H 2VPT); thermal, structural and spectroscopic studies

    NASA Astrophysics Data System (ADS)

    El-Reash, Gaber Abu; El-Ayaan, Usama; Gabr, I. M.; El-Rachawy, El-Bastawesy

    2010-04-01

    The present work carried out a study on the ligational behavior of the new ligand, Vanillin- 4N-(2-pyridyl) thiosemicarbazone (H 2VPT) 1 towards some transition metal ions namely, Mn 2+, Co 2+, Ni 2+, Cu 2+, Zn 2+,Cd 2+, Hg 2+ and U 6+. These complexes namely [Mn(HVPT)Cl] 2, [Co(VPT)(H 2O)] 2H 2O 3, [Ni(HVPT)Cl(H 2O)] 4, [Cu(HVPT)Cl(H 2O)] 5, [Zn(VPT)(H 2O)]H 2O 6, [Cd(HVPT)Cl(H 2O)] 7, [Hg(VPT)(H 2O)]H 2O 8 and [UO 2(H 2VPT)(OAc) 2]H 2O 9, were characterized by elemental analysis, spectral (IR, 1H NMR and UV-vis) and magnetic moment measurements. The suggested structures were confirmed by applying geometry optimization and conformational analysis. Thermal properties and decomposition kinetics of all compounds are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters ( E, A, Δ H, Δ S and Δ G) of all thermal decomposition stages have been evaluated using Coats-Redfern equation. ESR spectra of [Cu(HVPT)Cl]H 2O at room temperature show broad signal, indicating spin-exchange interactions between copper(II) ions.

  2. Mercaptursäure und Nukleosidaddukt im Harn als Biomarker in 1-Hydroxymethylpyren-exponierten Ratten

    NASA Astrophysics Data System (ADS)

    Ma, Lan

    2002-01-01

    1-Methylpyren (MP) ist hepatokanzerogen in neugeborenen männlichen Mäusen. Durch Hydroxylierung an der benzylischen Stelle und anschließende Sulfonierung wird MP zu DNA-reaktivem 1-Sulfooxymethylpyren (SMP) aktiviert. In der Ratte führt die Exposition des benzylischen Alkohols, 1-Hydroxymethylpyren (HMP), zur DNA-Adduktbildung in verschiedenen Geweben. Eventuelle Konsequenz der Toxifizierung ist die Ausscheidung entsprechender Mercaptursäure und Nukleosidaddukt im Harn, welche aufgrund ihrer Herkunft als Biomarker eignen könnten. In dieser Arbeit wird die Ausscheidung der Mercaptursäure und des N2-Desoxyguanosinadduktes in HMP-exponierten Ratten untersucht. Nach der Applikation von HMP bzw. MP wurden weniger als 1 % der Dosis als MPMA über Urin und Faeces ausgeschieden (0 - 48 h). Die Ausscheidung erfolgt hauptsächlich in den ersten 24 h nach der Applikation. MPdG konnte weder in Urin noch in Faeces der HMP-behandelten Tieren identifiziert werden. Nach direkter SMP-Applikation wurde MPdG nur in sehr geringe Menge (weniger als 0,9 ppm in 12 h) im Urin gefunden. Aufgrund der geringen Menge eignet sich MPdG nicht als Biomarker. MPMA dagegen, lässt sich analytisch gut erfassen. Es sollte daher untersucht werden, ob MPMA die Toxifizierung des HMP wiederspiegelt. Die Voraussetzung dafür ist die Kenntnisse über das Metabolismusmuster von HMP. Es wurde daher umfassende Untersuchungen zum Metabolismus des HMP durchgeführt. Die Ergebnisse zeigten, dass mehr als 80 % der Metaboiten in ihrer oxidierten Form (PCS, deren Glucuronsäure-Konjugate sowie phenolische Sulfatester der PCS) ausgeschieden wurden. Demnach spielt die Oxidation des HMP zu PCS eine sehr wichtige Rolle bei der Detoxifizierung und Ausscheidung von HMP. Ferne konnte nachgewiesen werden, dass die Enzyme Alkohol- und Aldehyd-Dehydrogenase an der Oxidation von HMP beteiligt waren. Die Inhibitoren Disulfiram und Ethanol der o. g. Enzyme wurde daher zur Modulation der Detoxifizierung in vivo eingesetzt

  3. Variational Perturbation Theory Path Integral Monte Carlo (VPT-PIMC): Trial Path Optimization Approach for Warm Dense Matter

    NASA Astrophysics Data System (ADS)

    Belof, Jonathan; Dubois, Jonathan

    2013-06-01

    Warm dense matter (WDM), the regime of degenerate and strongly coupled Coulomb systems, is of great interest due to it's importance in understanding astrophysical processes and high energy density laboratory experiments. Path Integral Monte Carlo (PIMC) presents a particularly attractive formalism for tackling outstanding questions in WDM, in that electron correlation can be calculated exactly, with the nuclear and electronic degrees of freedom on equal footing. Here we present an efficient means of solving the Feynman path integral numerically by variational optimization of a trial density matrix, a method originally proposed for simple potentials by Feynman and Kleinert, and we show that this formalism provides an accurate description of warm dense matter with a number of unique advantages over other PIMC approaches. An exchange interaction term is derived for the variationally optimized path, as well as a numerically efficient scheme for dealing with long-range electrostatics. Finally, we present results for the pair correlation functions and thermodynamic observables of the spin polarized electron gas, warm dense hydrogen and all-electron warm dense carbon within the presented VPT-PIMC formalism. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344.

  4. The theoretical-cum-statistical approach for the investigation of reaction NO2 + O(3P) → NO + O2 using SCTST and a full anharmonic VPT2 model

    NASA Astrophysics Data System (ADS)

    Shiekh, Bilal Ahmad; Kaur, Damanjit; Seth, Bharti; Mahajan, Shalagha

    2016-10-01

    The study of the titled reaction has been carried out using high-level quantum mechanics in conjugation with SCTST and VPT2 model. The many quantum mechanical methods have been employed in combinatory approach to find out the various properties such as energy, anharmonic vibrational coefficients and ro-vibrational parameters for the stationary points including the transition state of the reaction. Then the thermal rate coefficients were computed over a temperature regime of 150-1500 K and the corresponding results were compared with the available literature. In this temperature regime, our computed results are in excellent contrast with the experiment.

  5. Toward feasible and comprehensive computational protocol for simulation of the spectroscopic properties of large molecular systems: the anharmonic infrared spectrum of uracil in the solid state by the reduced dimensionality/hybrid VPT2 approach.

    PubMed

    Fornaro, Teresa; Carnimeo, Ivan; Biczysko, Malgorzata

    2015-05-28

    Feasible and comprehensive computational protocols for simulating the spectroscopic properties of large and complex molecular systems are very sought after. Indeed, due to the great variety of intra- and intermolecular interactions that may take place, the interpretation of experimental data becomes more and more difficult as the system under study increases in size or is placed in a complex environment, such as condensed phases. In this framework, we are actively developing a comprehensive and robust computational protocol aimed at quantitative reproduction of the spectra of nucleic acid base complexes, with increasing complexity toward condensed phases and monolayers of biomolecules on solid supports. We have resorted to fully anharmonic quantum mechanical computations within the generalized second-order vibrational perturbation theory (GVPT2) approach, combined with the cost-effective B3LYP-D3 method, in conjunction with basis sets of double-ζ plus polarization quality. Such an approach has been validated in a previous work ( Phys. Chem. Chem. Phys. 2014 , 16 , 10112 - 10128 ) for simulating the IR spectra of the monomers of nucleobases and some of their dimers. In the present contribution we have extended such computational protocol to simulate spectroscopic properties of a molecular solid, namely polycrystalline uracil. First we have selected a realistic molecular model for representing the spectroscopic properties of uracil in the solid state, the uracil heptamer, and then we have computed the relative anharmonic frequencies combining less demanding approaches such as the hybrid B3LYP-D3/DFTBA one, in which the harmonic frequencies are computed at a higher level of theory (B3LYP-D3/N07D) whereas the anharmonic shifts are evaluated at a lower level of theory (DFTBA), and the reduced dimensionality VPT2 (RD-VPT2) approach, where only selected vibrational modes are computed anharmonically along with the couplings with other modes. The good agreement between the

  6. Toward feasible and comprehensive computational protocol for simulation of the spectroscopic properties of large molecular systems: the anharmonic infrared spectrum of uracil in the solid state by the reduced dimensionality/hybrid VPT2 approach.

    PubMed

    Fornaro, Teresa; Carnimeo, Ivan; Biczysko, Malgorzata

    2015-05-28

    Feasible and comprehensive computational protocols for simulating the spectroscopic properties of large and complex molecular systems are very sought after. Indeed, due to the great variety of intra- and intermolecular interactions that may take place, the interpretation of experimental data becomes more and more difficult as the system under study increases in size or is placed in a complex environment, such as condensed phases. In this framework, we are actively developing a comprehensive and robust computational protocol aimed at quantitative reproduction of the spectra of nucleic acid base complexes, with increasing complexity toward condensed phases and monolayers of biomolecules on solid supports. We have resorted to fully anharmonic quantum mechanical computations within the generalized second-order vibrational perturbation theory (GVPT2) approach, combined with the cost-effective B3LYP-D3 method, in conjunction with basis sets of double-ζ plus polarization quality. Such an approach has been validated in a previous work ( Phys. Chem. Chem. Phys. 2014 , 16 , 10112 - 10128 ) for simulating the IR spectra of the monomers of nucleobases and some of their dimers. In the present contribution we have extended such computational protocol to simulate spectroscopic properties of a molecular solid, namely polycrystalline uracil. First we have selected a realistic molecular model for representing the spectroscopic properties of uracil in the solid state, the uracil heptamer, and then we have computed the relative anharmonic frequencies combining less demanding approaches such as the hybrid B3LYP-D3/DFTBA one, in which the harmonic frequencies are computed at a higher level of theory (B3LYP-D3/N07D) whereas the anharmonic shifts are evaluated at a lower level of theory (DFTBA), and the reduced dimensionality VPT2 (RD-VPT2) approach, where only selected vibrational modes are computed anharmonically along with the couplings with other modes. The good agreement between the

  7. Materials Data on VPt (SG:123) by Materials Project

    DOE Data Explorer

    Kristin Persson

    2016-04-23

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  8. Materials Data on VPt3 (SG:139) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  9. Protein sorting in Saccharomyces cerevisiae: isolation of mutants defective in the delivery and processing of multiple vacuolar hydrolases.

    PubMed Central

    Robinson, J S; Klionsky, D J; Banta, L M; Emr, S D

    1988-01-01

    Using a selection for spontaneous mutants that mislocalize a vacuolar carboxypeptidase Y (CPY)-invertase fusion protein to the cell surface, we identified vacuolar protein targeting (vpt) mutants in 25 new vpt complementation groups. Additional alleles in each of the eight previously identified vpt complementation groups (vpt1 through vpt8) were also obtained. Representative alleles from each of the 33 vpt complementation groups (vpt1 through vpt33) were shown to exhibit defects in the sorting and processing of several native vacuolar proteins, including the soluble hydrolases CPY, proteinase A, and proteinase B. Of the 33 complementation groups, 19 were found to contain mutant alleles that led to extreme defects. In these mutants, CPY accumulated in its Golgi complex-modified precursor form which was secreted by the mutant cells. Normal protein secretion appeared to be unaffected in the vpt mutants. The lack of significant leakage of cytosolic markers from the vpt mutant cells indicated that the vacuolar protein-sorting defects associated with these mutants do not result from cell lysis. In addition, the observation that the precursor rather than the mature forms of CPY, proteinase A, proteinase B were secreted from the vpt mutants was consistent with the fact that mislocalization occurred at a stage after Golgi complex-specific modification, but before final vacuolar sorting of these enzymes. Vacuolar membrane protein sorting appeared to be unaffected in the majority of the vpt mutants. However, a subset of the vpt mutants (vpt11, vpt16, vpt18, and vpt33) was found to exhibit defects in the sorting of a vacuolar membrane marker enzyme, alpha-mannosidase. Up to 50% of the alpha-mannosidase enzyme activity was found to be mislocalized to the cell surface in these vpt mutants. Seven of the vpt complementation groups (vpt3, vpt11, vpt15, vpt16, vpt18, vpt29, and vpt33) contained alleles that led to a conditional lethal phenotype; the mutants were temperature

  10. The Two Forms of Visuo-Spatial Perspective Taking are Differently Embodied and Subserve Different Spatial Prepositions

    PubMed Central

    Kessler, Klaus; Rutherford, Hannah

    2010-01-01

    We set out to distinguish level 1 (VPT-1) and level 2 (VPT-2) perspective taking with respect to the embodied nature of the underlying processes as well as to investigate their dependence or independence of response modality (motor vs. verbal). While VPT-1 reflects understanding of what lies within someone else's line of sight, VPT-2 involves mentally adopting someone else's spatial point of view. Perspective taking is a high-level conscious and deliberate mental transformation that is crucially placed at the convergence of perception, mental imagery, communication, and even theory of mind in the case of VPT-2. The differences between VPT-1 and VPT-2 mark a qualitative boundary between humans and apes, with the latter being capable of VPT-1 but not of VPT-2. However, our recent data showed that VPT-2 is best conceptualized as the deliberate simulation or emulation of a movement, thus underpinning its embodied origins. In the work presented here we compared VPT-2 to VPT-1 and found that VPT-1 is not at all, or very differently embodied. In a second experiment we replicated the qualitatively different patterns for VPT-1 and VPT-2 with verbal responses that employed spatial prepositions. We conclude that VPT-1 is the cognitive process that subserves verbal localizations using “in front” and “behind,” while VPT-2 subserves “left” and “right” from a perspective other than the egocentric. We further conclude that both processes are grounded and situated, but only VPT-2 is embodied in the form of a deliberate movement simulation that increases in mental effort with distance and incongruent proprioception. The differences in cognitive effort predict differences in the use of the associated prepositions. Our findings, therefore, shed light on the situated, grounded and embodied basis of spatial localizations and on the psychology of their use. PMID:21833268

  11. The role of torsional motion on the properties of propiolic acid and its H/D isotopic analogs: A density functional study using SCTST and a full anharmonic VPT2 model

    NASA Astrophysics Data System (ADS)

    Shiekh, Bilal Ahmad; Kaur, Damanjit

    2016-02-01

    The conformational isomerization of propiolic acid and its H/D isotopic counterparts are studied by using high-level quantum chemistry in conjugation with semiclassical transition state theory and second order vibrational perturbation theory. The electronic structure calculations were carried at DFT and MP2 levels of theory. The vibrational anharmonicity coefficients including the fully coupled vibrational modes of the reaction coordinate of the transition state, used in semiclassical transition state theory, are computed at hybrid functional B3LYP in conjugation with aug-cc-pVTZ and SNSD basis sets. The corresponding solutions give rate as well as the equilibrium constants between the isomers and the isotopic analogs.

  12. The corpus callosum and empathy in adults with a history of preterm birth.

    PubMed

    Lawrence, E J; Allen, G M; Walshe, M; Allin, M; Murray, R; Rifkin, L; McGuire, P K; Nosarti, C

    2010-07-01

    Reduced posterior corpus callosum (CC) area has been consistently observed in children and adolescents born very preterm (VPT). CC structural differences are also observed in people diagnosed with empathy disorders. This study examined empathy in relation to CC size in VPT adults and controls. CC area was manually measured for 17 VPT adults and 9 controls. Participants completed the Interpersonal Reactivity Index (Davis, 1980) and the Empathy Quotient (Baron-Cohen & Wheelwright, 2004). VPT adults had reduced posterior CC area in contrast to controls, and a positive linear trend was observed between posterior CC size and gestational age. No between-group empathy differences were observed, although self-reported personal distress in response to social situations was higher in VPT adults, and negatively associated with anterior CC area. We conclude that VPT adults have a smaller posterior CC, which is associated with gestational age, and elevated social distress, which may be mediated by anterior CC size.

  13. Fourth-Order Vibrational Transition State Theory and Chemical Kinetics

    NASA Astrophysics Data System (ADS)

    Stanton, John F.; Matthews, Devin A.; Gong, Justin Z.

    2015-06-01

    Second-order vibrational perturbation theory (VPT2) is an enormously successful and well-established theory for treating anharmonic effects on the vibrational levels of semi-rigid molecules. Partially as a consequence of the fact that the theory is exact for the Morse potential (which provides an appropriate qualitative model for stretching anharmonicity), VPT2 calculations for such systems with appropriate ab initio potential functions tend to give fundamental and overtone levels that fall within a handful of wavenumbers of experimentally measured positions. As a consequence, the next non-vanishing level of perturbation theory -- VPT4 -- offers only slight improvements over VPT2 and is not practical for most calculations since it requires information about force constants up through sextic. However, VPT4 (as well as VPT2) can be used for other applications such as the next vibrational correction to rotational constants (the ``gammas'') and other spectroscopic parameters. In addition, the marriage of VPT with the semi-classical transition state theory of Miller (SCTST) has recently proven to be a powerful and accurate treatment for chemical kinetics. In this talk, VPT4-based SCTST tunneling probabilities and cumulative reaction probabilities are give for the first time for selected low-dimensional model systems. The prospects for VPT4, both practical and intrinsic, will also be discussed.

  14. Network interdependency between social media and stock trading activities: Evidence from China

    NASA Astrophysics Data System (ADS)

    Lin, Shen; Ren, Da; Zhang, Wei; Zhang, Yongjie; Shen, Dehua

    2016-06-01

    The emergence of social media accelerates the research on information dissemination and its corresponding influence on trading tendency. Based on empirical study of the dynamic relationship between the ratio of re-post microblog and original microblog (RRO) and average volume per transaction (VPT), we find the following results: (1) In microblog network, stocks with high RRO are often accompanied with low statistical VPT; (2) When the discussion about one stock is quite lively in microblog network (such as the blog postings reach a summit), it does not statistically cause the fluctuations of VPT of the stock; (3) Overall speaking, RRO plays a significant role in inverting u-shaped relationship with VPT.

  15. Alterations in the optic radiations of very preterm children-Perinatal predictors and relationships with visual outcomes.

    PubMed

    Thompson, Deanne K; Thai, Dolly; Kelly, Claire E; Leemans, Alexander; Tournier, Jacques-Donald; Kean, Michael J; Lee, Katherine J; Inder, Terrie E; Doyle, Lex W; Anderson, Peter J; Hunt, Rodney W

    2014-01-01

    Children born very preterm (VPT) are at risk for visual impairments, the main risk factors being retinopathy of prematurity and cerebral white matter injury, however these only partially account for visual impairments in VPT children. This study aimed to compare optic radiation microstructure and volume between VPT and term-born children, and to investigate associations between 1) perinatal variables and optic radiations; 2) optic radiations and visual function in VPT children. We hypothesized that optic radiation microstructure would be altered in VPT children, predicted by neonatal cerebral white matter abnormality and retinopathy of prematurity, and associated with visual impairments. 142 VPT children and 32 controls underwent diffusion-weighted magnetic resonance imaging at 7 years of age. Optic radiations were delineated using constrained spherical deconvolution tractography. Tract volume and average diffusion tensor values for the whole optic radiations and three sub-regions were compared between the VPT and control groups, and correlated with perinatal variables and 7-year visual outcome data. Total tract volumes and average diffusion values were similar between VPT and control groups. On regional analysis of the optic radiation, mean and radial diffusivity were higher within the middle sub-regions in VPT compared with control children. Neonatal white matter abnormalities and retinopathy of prematurity were associated with optic radiation diffusion values. Lower fractional anisotropy in the anterior sub-regions was associated with poor visual acuity and increased likelihood of other visual defects. This study presents evidence for microstructural alterations in the optic radiations of VPT children, which are largely predicted by white matter abnormality or severe retinopathy of prematurity, and may partially explain the higher rate of visual impairments in VPT children.

  16. Neonatal Cerebral Morphometry and Later Risk of Persistent Inattention/Hyperactivity in Children Born Very Preterm

    ERIC Educational Resources Information Center

    Bora, Samudragupta; Pritchard, Verena E.; Chen, Zhe; Inder, Terrie E.; Woodward, Lianne J.

    2014-01-01

    Background: Attention problems are among the most prevalent neurobehavioral morbidities affecting very preterm (VPT) born children. The first study aim was to document rates of persistent attention/hyperactivity problems from ages 4 to 9 years in a regional cohort of VPT born children. The second aim was to examine the extent to which persistent…

  17. Visual to Print Transfer: A Literacy Strategy for Theme Analysis of Text

    ERIC Educational Resources Information Center

    Buelow, Stephanie

    2015-01-01

    This article shares a literacy strategy to support students' analysis of the theme of text and provide evidence to support their assertion. The strategy is called Visual to Print Transfer (VPT). The VPT strategy leverages students' out-of-school literacy practices involving media images of Hollywood icons as a way to support their understanding of…

  18. Socio-Economic Achievements of Individuals Born Very Preterm at the Age of 27 to 29 Years: A Nationwide Cohort Study

    ERIC Educational Resources Information Center

    Mathiasen, Rene; Hansen, Bo M.; Anderson, Anne-Marie Nybo; Greisen, Gorm

    2009-01-01

    Aim: To describe the socio economic achievement of individuals born very preterm (VPT) at the age of 27 to 29 years. Method: Demographic and social data were extracted from national registers for all individuals born between 1974 and 1976 in Denmark (n = 208 656). Of these, 203 283 individuals were alive in 2006. We compared VPT individuals…

  19. Psychiatric Outcomes at Age Seven for Very Preterm Children: Rates and Predictors

    ERIC Educational Resources Information Center

    Treyvaud, Karli; Ure, Alexandra; Doyle, Lex W.; Lee, Katherine J.; Rogers, Cynthia E.; Kidokoro, Hiroyuki; Inder, Terrie E.; Anderson, Peter J.

    2013-01-01

    Background: Uncertainty remains about the rate of specific psychiatric disorders and associated predictive factors for very preterm (VPT) children. The aims of this study were to document rates of psychiatric disorders in VPT children aged 7 years compared with term born children, and to examine potential predictive factors for psychiatric…

  20. Corpus Callosum and Prefrontal Functions in Adolescents with History of Very Preterm Birth

    ERIC Educational Resources Information Center

    Narberhaus, Ana; Segarra, Dolors; Caldu, Xavier; Gimenez, Monica; Pueyo, Roser; Botet, Francesc; Junque, Carme

    2008-01-01

    Very preterm (VPT) birth can account for thinning of the corpus callosum and poorer cognitive performance. Research findings about preterm and VPT adolescents usually describe a small posterior corpus callosum, although our research group has also found reductions of the anterior part, specifically the genu. The aim of the present study was to…

  1. Very Preterm Adolescents Show Gender-Dependent Alteration of the Structural Brain Correlates of Spelling Abilities

    ERIC Educational Resources Information Center

    Scott, Fiona E.; Mechelli, Andrea; Allin, Matthew P.; Walshe, Muriel; Rifkin, Larry; Murray, Robin M.; Nosarti, Chiara

    2011-01-01

    Individuals born very preterm (VPT) are at risk of neurodevelopmental damage and of adverse educational outcomes in childhood and adolescence. The present study used voxel-based morphometry to investigate the association between grey matter and white matter volume and measures of language and executive functioning in VPT born adolescents and…

  2. Cerebellar Growth and Behavioural & Neuropsychological Outcome in Preterm Adolescents

    ERIC Educational Resources Information Center

    Parker, Jennifer; Mitchell, Ann; Kalpakidou, Anastasia; Walshe, Muriel; Jung, Hee-Yeon; Nosarti, Chiara; Santosh, Paramala; Rifkin, Larry; Wyatt, John; Murray, Robin M.; Allin, Matthew

    2008-01-01

    Adolescence is a time of social and cognitive development associated with changes in brain structure and function. These developmental changes may show an altered path in individuals born before 33 weeks' gestation (very preterm; VPT). The cerebellum is affected by VPT birth, but no studies have yet assessed the adolescent development of this…

  3. Specific Language Impairment, Theory of Mind, and Visual Perspective Taking: Evidence for Simulation Theory and the Developmental Role of Language

    ERIC Educational Resources Information Center

    Farrant, Brad M.; Fletcher, Janet; Maybery, Murray T.

    2006-01-01

    Recent research has found that the acquisition of theory of mind (ToM) is delayed in children with specific language impairment (SLI). The present study used a battery of ToM and visual perspective taking (VPT) tasks to investigate whether the delayed acquisition of ToM in children with SLI is associated with delayed VPT development. Harris'…

  4. Identification of volume phase transition of a single microgel particle using optical tweezers

    NASA Astrophysics Data System (ADS)

    Karthickeyan, D.; Gupta, Deepak K.; Tata, B. V. R.

    2016-10-01

    Poly (N-isopropyl acrylamide-co-acrylic acid) (PNIPAM-co-Aac) microgel particles are pH responsive and exhibit volume phase transition (VPT) upon variation of pH. Dynamic light scattering (DLS) is used conventionally to identify VPT and requires a dilute suspension with particle concentration ˜107 particles cm-3 and if particles are polydisperse in nature, DLS data interpretation is relatively difficult. Here we show that optical tweezers allow one to measure the VPT of a single microgel particle by measuring the optical trap stiffness, κ of trapped particle as a function of pH. We report here a sudden change in κ at VPT, which is shown to arise from a sudden decrease in particle diameter with a concomitant increase in the refractive index of the particle at VPT.

  5. A vacuolar phosphate transporter essential for phosphate homeostasis in Arabidopsis

    PubMed Central

    Liu, Jinlong; Yang, Lei; Luan, Mingda; Wang, Yuan; Zhang, Chi; Zhang, Bin; Shi, Jisen; Zhao, Fu-Geng; Lan, Wenzhi; Luan, Sheng

    2015-01-01

    Inorganic phosphate (Pi) is stored in the vacuole, allowing plants to adapt to variable Pi availability in the soil. The transporters that mediate Pi sequestration into vacuole remain unknown, however. Here we report the functional characterization of Vacuolar Phosphate Transporter 1 (VPT1), an SPX domain protein that transports Pi into the vacuole in Arabidopsis. The vpt1 mutant plants were stunted and consistently retained less Pi than wild type plants, especially when grown in medium containing high levels of Pi. In seedlings, VPT1 was expressed primarily in younger tissues under normal conditions, but was strongly induced by high-Pi conditions in older tissues, suggesting that VPT1 functions in Pi storage in young tissues and in detoxification of high Pi in older tissues. As a result, disruption of VPT1 rendered plants hypersensitive to both low-Pi and high-Pi conditions, reducing the adaptability of plants to changing Pi availability. Patch-clamp analysis of isolated vacuoles showed that the Pi influx current was severely reduced in vpt1 compared with wild type plants. When ectopically expressed in Nicotiana benthamiana mesophyll cells, VPT1 mediates vacuolar influx of anions, including Pi, SO42−, NO3−, Cl−, and malate with Pi as that preferred anion. The VPT1-mediated Pi current amplitude was dependent on cytosolic phosphate concentration. Single-channel analysis showed that the open probability of VPT1 was increased with the increase in transtonoplast potential. We conclude that VPT1 is a transporter responsible for vacuolar Pi storage and is essential for Pi adaptation in Arabidopsis. PMID:26554016

  6. Cortical Gray and Adjacent White Matter Demonstrate Synchronous Maturation in Very Preterm Infants.

    PubMed

    Smyser, Tara A; Smyser, Christopher D; Rogers, Cynthia E; Gillespie, Sarah K; Inder, Terrie E; Neil, Jeffrey J

    2016-08-01

    Spatial and functional gradients of development have been described for the maturation of cerebral gray and white matter using histological and radiological approaches. We evaluated these patterns in very preterm (VPT) infants using diffusion tensor imaging. Data were obtained from 3 groups: 1) 22 VPT infants without white matter injury (WMI), of whom all had serial MRI studies during the neonatal period, 2) 19 VPT infants with WMI, of whom 3 had serial MRI studies and 3) 12 healthy, term-born infants. Regions of interest were placed in the cortical gray and adjacent white matter in primary motor, primary visual, visual association, and prefrontal regions. From the MRI data at term-equivalent postmenstrual age, differences in mean diffusivity were found in all areas between VPT infants with WMI and the other 2 groups. In contrast, minimal differences in fractional anisotropy were found between the 3 groups. These findings suggest that cortical maturation is delayed in VPT infants with WMI when compared with term control infants and VPT infants without WMI. From the serial MRI data from VPT infants, synchronous development between gray and white matter was evident in all areas and all groups, with maturation in primary motor and sensory regions preceding that of association areas. This finding highlights the regionally varying but locally synchronous nature of the development of cortical gray matter and its adjacent white matter.

  7. Cognitive Mechanisms underlying visual perspective taking in typical and ASC children.

    PubMed

    Pearson, Amy; Marsh, Lauren; Ropar, Danielle; Hamilton, Antonia

    2016-01-01

    Previous research has suggested that people with Autism Spectrum Conditions (ASC) may have difficulty with visual perspective taking (VPT) but it is not clear how this relates to different strategies that can be used in perspective taking tasks. The current study examined VPT in 30 children with autism and 30 verbal mental age matched typical children, in comparison to mental rotation (MR) abilities and body representation abilities. Using a similar paradigm to Hamilton, Brindley, and Frith [2009] all children completed three tasks: a VPT task in which children decided what a toy on a table would look like from a different points of view; a MR task in which the child decided what a toy would look like after it had been rotated; and a body posture matching task, in which children matched pictures of a body shown from different viewpoints. Results showed that children with ASC performed better than the typically developing children on the MR task, and at a similar level on the VPT task and body matching task. Importantly, in the typical children VPT performance was predicted by performance on the body matching task, whereas in the ASC children VPT performance was predicted by MR ability. These findings suggest that differences in VPT in ASC may be explained by the use of a spatial rotation strategy rather than the embodied egocentric transformation strategy used by typical children. PMID:26052836

  8. Pain-related stress during the Neonatal Intensive Care Unit stay and SLC6A4 methylation in very preterm infants

    PubMed Central

    Provenzi, Livio; Fumagalli, Monica; Sirgiovanni, Ida; Giorda, Roberto; Pozzoli, Uberto; Morandi, Francesco; Beri, Silvana; Menozzi, Giorgia; Mosca, Fabio; Borgatti, Renato; Montirosso, Rosario

    2015-01-01

    Very preterm (VPT) infants need long-lasting hospitalization in the Neonatal Intensive Care Unit (NICU) during which they are daily exposed to pain-related stress. Alterations of DNA methylation at the promoter region of the SLC6A4 have been associated with early adverse experiences in infants. The main aim of the present work was to investigate the association between level of exposure to pain-related stress during hospitalization and changes in SLC6A4 DNA methylation at NICU discharge in VPT infants. In order to exclude the potential effect of birth status (i.e., preterm vs. full-term birth) on SLC6A4 methylation, we preliminarily assessed SLC6A4 epigenetic differences between VPT and full-term (FT) infants at birth. Fifty-six VPT and thirty-two FT infants participated in the study. The level of exposure to pain-related stress was quantified on the basis of the amount of skin-breaking procedures to which they were exposed. VPT infants were divided in two sub-groups: low-pain exposure (LPE, N = 25) and high-pain exposure (HPE, N = 31). DNA methylation was evaluated at birth for both VPT and FT infants, assessing 20 CpG sites within the SLC6A4 promoter region. The same CpG sites were re-evaluated for variations in DNA methylation at NICU discharge in LPE and HPE VPT infants. No differences in SLC6A4 CpG sites' methylation emerged between FT and VPT infants at birth. Methylation at CpG sites 5 and 6 significantly increased from birth to NICU discharge only for HPE VPT infants. Findings show that preterm birth per se is not associated with epigenetic alterations of the SLC6A4, whereas higher levels of pain-related stress exposure during NICU stay might alter the transcriptional functionality of the serotonin transporter gene. PMID:25941480

  9. Neurodevelopmental outcomes and neural mechanisms associated with non-right handedness in children born very preterm

    PubMed Central

    Pascoe, L; Scratch, SE; Burnett, AC; Thompson, DK; Lee, KJ; Doyle, LW; Cheong, JLY; Inder, TE; Anderson, PJ

    2016-01-01

    Objective Non-right handedness (NRH) is reportedly more common in very preterm (VPT; <32 weeks’ gestation) children compared with term-born peers, but it is unclear whether neonatal brain injury or altered brain morphology and microstructure underpins NRH in this population. Given that NRH has been inconsistently reported to be associated with cognitive and motor difficulties, this study aimed to examine associations between handedness and neurodevelopmental outcomes in VPT 7 year-olds. Further, the relationship between neonatal brain injury and integrity of motor tracts (corpus callosum and corticospinal tract) with handedness at age 7 years in VPT children was explored. Method One hundred and seventy-five VPT and 69 term-born children completed neuropsychological and motor assessments and a measure of handedness at 7 years’ corrected age. At term-equivalent age, brain injury on MRI was assessed and diffusion tensor measures were obtained for the corpus callosum and posterior limb of the internal capsule. Results There was little evidence of stronger NRH in the VPT group compared with term controls (regression coefficient [b] −1.95, 95% confidence interval [CI] −5.67 to 1.77). Poorer academic and working memory outcomes were associated with stronger NRH in the VPT group. While there was little evidence that neonatal unilateral brain injury was associated with stronger NRH, increased area and fractional anisotropy of the corpus callosum splenium were predictive of stronger NRH in the VPT group. Conclusions VPT birth may alter the relationship between handedness and academic outcomes, and neonatal corpus callosum integrity predicts hand preference in VPT children at school age. PMID:26328609

  10. Specific language impairment, theory of mind, and visual perspective taking: evidence for simulation theory and the developmental role of language.

    PubMed

    Farrant, Brad M; Fletcher, Janet; Maybery, Murray T

    2006-01-01

    Recent research has found that the acquisition of theory of mind (ToM) is delayed in children with specific language impairment (SLI). The present study used a battery of ToM and visual perspective taking (VPT) tasks to investigate whether the delayed acquisition of ToM in children with SLI is associated with delayed VPT development. Harris' (1992, 1996) simulation theory predicts that the development of VPT will be delayed. Participants were 20 children with SLI (M=62.9 months) and 20 typically developing children (M=61.2 months) who were matched for nonverbal ability, gender, and age. The results supported Harris' theory and a role for language in ToM and VPT development.

  11. Vacuolar SPX-MFS transporters are essential for phosphate adaptation in plants.

    PubMed

    Liu, Jinlong; Fu, Shaomin; Yang, Lei; Luan, Mingda; Zhao, Fugeng; Luan, Sheng; Lan, Wenzhi

    2016-08-01

    To survive in most soils in which inorganic phosphate (Pi) levels are limited and constantly changing, plants universally use the vacuoles as cellular Pi "sink" and "source" to maintain Pi homeostasis. However, the transporters that mediate Pi sequestration into the vacuoles remain unknown. Recently, we and other 2 groups independently identified the members of SPS-MSF family as the candidates for tonoplast Pi transporters in Arabidopsis thaliana and Oryza sativa. We and Liu et al. demonstrated that one of SPS-MSF member, VPT1 (Vacuolar Phosphate Transporter 1), also named as PHT5;1 (Phosphate Transporter 5;1), plays a predominant role in Pi sequestration of vacuoles in Arabidopsis. Here we show that vpt1 mutants and VPT1-GFP overexpressing lines displayed sensitive to Pi stress under the hydroponic system containing the medium with low iron, supporting that VPT1 is essential for Arabidopsis to adapt phosphate stress. PMID:27467463

  12. [Virion precipitation reaction based on determination of reverse transcriptase activity: Method of study of membrane antigens of oncornaviruses].

    PubMed

    Zakharova, L G; Al'tshtein, A D

    1978-01-01

    A method for the study of the envelope antigens of oncornaviruses of C, B, and D types by the virion precipitation test (VPT) based on the measurement of the amount of precipitated virus by its reverse transcriptase activity is described. The method is immunologically specific for titration of antibody to the envelope antigens of oncornaviruses. By means of the VPT it is possible to identify oncornaviruses, to study antigenic relationships between them and to detect some or other antigens in virion coat.

  13. Transmastoid reshaping of the sigmoid sinus: preliminary study of a novel surgical method to quiet pulsatile tinnitus of an unrecognized vascular origin.

    PubMed

    Kim, Chong Sun; Kim, So Young; Choi, Hyunseok; Koo, Ja-Won; Yoo, Shin-Young; An, Gwang Seok; Lee, Kyogu; Choi, Inyong; Song, Jae-Jin

    2016-08-01

    OBJECTIVE A dominant sigmoid sinus with focal dehiscence or thinning (DSSD/T) of the overlying bony wall is a commonly encountered, but frequently overlooked, cause of vascular pulsatile tinnitus (VPT). Also, the pathophysiological mechanism of sound perception in patients with VPT remains poorly understood. In the present study, a novel surgical method, termed transmastoid SS-reshaping surgery, was introduced to ameliorate VPT in patients with DSSD/T. The authors reviewed a case series, analyzed the surgical outcomes, and suggested the pathophysiological mechanism of sound perception. The theoretical background underlying VPT improvement after transmastoid SS-reshaping surgery was also explored. METHODS Eight patients with VPT that was considered attributable to DSSD/T underwent transmastoid SS-reshaping surgery between February 2010 and February 2015. The mean postoperative follow-up period was 9.5 months (range 4-13 months). Transmastoid SS-reshaping surgery featured simple mastoidectomy, partial compression of the SS using harvested cortical bone chips, and reinforcement of the bony SS wall with bone cement. Perioperative medical records, imaging results, and audiological findings were comprehensively reviewed. RESULTS In 7 of the 8 patients (87.5%), the VPT abated immediately after surgery. Statistically significant improvements in tinnitus loudness and distress were evident on numeric rating scales. Three patients with preoperative ipsilesional low-frequency hearing loss exhibited postoperative improvements in their low-frequency hearing thresholds. No major postoperative complications were encountered except in the first subject, who experienced increased intracranial pressure postoperatively. This subsided after a revision operation for partial decompression of the SS. CONCLUSIONS Transmastoid SS-reshaping surgery may be a good surgical option in patients with DSSD/T, a previously unrecognized cause of VPT. Redistribution of severely asymmetrical blood flow

  14. Bioceramic Materials and the Changing Concepts in Vital Pulp Therapy.

    PubMed

    Cao, Yangpei; Bogen, George; Lim, Jung; Shon, Won-Jun; Kang, Mo K

    2016-05-01

    Vital pulp therapy (VPT) is devised to preserve and maintain vitality of pulpally involved teeth challenged by a variety of intraoral conditions. Notable progress has been made in this field due to a better understanding of pulp physiology, improved clinical protocols and advanced bioceramic materials paired with adhesive technology. With focused case selection, conservative VPT can provide reliable treatment options for permanent teeth diagnosed with normal pulps or reversible pulpitis. PMID:27290822

  15. Elevated Vibration Perception Thresholds in CIDP Patients Indicate More Severe Neuropathy and Lower Treatment Response Rates

    PubMed Central

    Abraham, Alon; Albulaihe, Hana; Alabdali, Majed; Qrimli, Mohammad; Breiner, Ari; Barnett, Carolina; Katzberg, Hans D.; Lovblom, Leif E.; Perkins, Bruce A.; Bril, Vera

    2015-01-01

    Introduction Vibration perception threshold (VPT) examination using a neurothesiometer provides objective, sensitive and specific information, and has been utilized mainly in patients with diabetic polyneropathy. Objectives Explore the utility of VPT examination in CIDP patients. Methods CIDP subjects attending the Neuromuscular clinic between 01/2013 and 12/2014 were evaluated. Demographic data, clinical history, physical examination, VPT values, and electrophysiologic data from their charts were extracted. Results 70 charts were reviewed. 55 CIDP patients had elevated VPT, associated with higher frequency of abnormal sensory testing for various modalities (92.7% vs. 46.7%, p<0.0001), lower sensory and motor amplitudes and reduced conduction velocities on nerve conduction studies, and lower treatment response rates (54% vs. 93%, p = 0.01). Conclusion VPT examination is a simple tool, which is a reliable and sensitive measure not only for diabetic neuropathy, but also for CIDP. Moreover, in CIDP, elevated VPT values are also associated with lower treatment response rates. PMID:26545096

  16. Semiclassical Transition-State Theory Based on Fourth-Order Vibrational Perturbation Theory: The Symmetrical Eckart Barrier.

    PubMed

    Stanton, John F

    2016-07-21

    Semiclassical transition-state theory based on fourth-order vibrational perturbation theory (VPT4-SCTST) is applied to compute the barrier transmission coefficient for the symmetric Eckart potential. For a barrier parametrized to mimic the H2 + H exchange reaction, the results obtained are in excellent agreement with exact quantum calculations over a range of energy that extends down to roughly 1% of the barrier height, V0, where tunneling is negligible. The VPT2-SCTST treatment, which is commonly used in chemical kinetics studies, also performs quite well but already shows an error of a few percent at ca. 0.8 V0 where tunneling is still important. This suggests that VPT4-SCTST could offer an improvement over VPT2-SCTST in applications studies. However, the computational effort for VPT4-SCTST treatments of molecules is excessive, and any improvement gained is unlikely to warrant the increased effort. Nevertheless, the treatment of the symmetric Eckart barrier problem here suggests a simple modification of the usual VPT2-SCTST protocol that warrants further investigation. PMID:27358083

  17. Pre-Treatment Objective Diagnosis and Post-Treatment Outcome Evaluation in Patients with Vascular Pulsatile Tinnitus Using Transcanal Recording and Spectro-Temporal Analysis

    PubMed Central

    Choi, Inyong; Koo, Ja-Won; Lee, Kyogu

    2016-01-01

    Objective Although vascular pulsatile tinnitus (VPT) has been classified as “objective”, VPT is not easily recognizable or documentable in most cases. In response to this, we have developed transcanal sound recording (TSR) and spectro-temporal analysis (STA) for the objective diagnosis of VPT. By refining our initial method, we were able to apply TSR/STA to post-treatment outcome evaluation, as well as pre-treatment objective diagnosis. Methods TSR was performed on seven VPT patients and five normal controls before and after surgical or interventional treatment. VPT was recorded using an inserted microphone with the subjects placed in both upright and supine positions with 1) a neutral head position, 2) head rotated to the tinnitus side, 3) head rotated to the non-tinnitus side, and 4) a neutral position with ipsi-lesional manual cervical compression. The recorded signals were analyzed in both time and time-frequency domains by performing a short-time Fourier transformation. Results The pre-treatment ear canal signals of all VPT patients demonstrated pulse-synchronous periodic structures and acoustic characteristics that were representative of their presumptive vascular pathologies, whereas those the controls exhibited smaller peaks and weak periodicities. Compared with the pre-treatment signals, the post-treatment signals exhibited significantly reduced peak- and root mean square amplitudes upon time domain analysis. Additionally, further sub-band analysis confirmed that the pulse-synchronous signal of all subjects was not identifiable after treatment and, in particular, that the signal decrement was statistically significant at low frequencies. Moreover, the post-treatment signals of the VPT subjects revealed no significant differences when compared to those of the control group. Conclusion We reconfirmed that the TSR/STA method is an effective modality to objectify VPT. In addition, the potential role of the TSR/STA method in the objective evaluation of

  18. Effect of vestibular rehabilitation on passive dynamic visual acuity.

    PubMed

    Scherer, Matthew; Migliaccio, Americo A; Schubert, Michael C

    2008-01-01

    While active dynamic visual acuity (DVA) has been shown to improve with gaze stabilization exercises, we sought to determine whether DVA during passive head impulses (pDVA) would also improve following a rehabilitation course of vestibular physical therapy (VPT) in patients with unilateral and bilateral vestibular hypofunction. VPT consisted of gaze and gait stabilization exercises done as a home exercise program. Scleral search coil was used to characterize the angular vestibulo-ocular reflex (aVOR) during pDVA before and after VPT. Mean duration of VPT was 66 +/- 24 days, over a total of 5 +/- 1.4 outpatient visits. Two of three subjects showed improvements in pDVA with a mean reduction of 43% (LogMAR 0.58 to 0.398 and 0.92 to 0.40). Our data suggest improvements in pDVA may be due in part to improvements in aVOR velocity and acceleration gains or reduced latency of the aVOR. Each subject demonstrated a reduction in the ratio of compensatory saccades to head impulses after VPT. Preliminary data suggest that active gaze stability exercises may contribute to improvements in pDVA in some individuals.

  19. IP-based narrow-band videophone system

    NASA Astrophysics Data System (ADS)

    Zhang, Zhengbing; Zhu, Dongmei; Xue, Liang; Zhu, Guangxi

    2005-02-01

    Architecture of an IP-based narrow-band videophone system is proposed in this paper for convenient videophone calls between any two computers even if being placed in two different LANs within network agents. The bandwidth need of each call is less than 256 kbps. The system consists of two kinds of entities: Videophone Terminals (VPT) and a Video Call Server (VCS). A VPT is actually a microcomputer program, composed of 4 primary parts, an audio codec, a video codec, a media deliverer/receiver and a call controller. The basic functions of the VCS include videophone number generation and management, access admission and address resolution. The VCS with a public IP address plays an important role in the system especially when a video call has to penetrate through network agents. Each VPT in the system gets its own external transport address from the VCS through registration process. A calling VPT would receive the external transport address of the called VPT from the VCS through address resolution. The proposed system works and is helpful to accelerate the realization of people's videophone dream over IP networks.

  20. Eating disorder psychopathology, brain structure, neuropsychological correlates and risk mechanisms in very preterm young adults.

    PubMed

    Micali, Nadia; Kothari, Radha; Nam, Kie Woo; Gioroukou, Elena; Walshe, Muriel; Allin, Matthew; Rifkin, Larry; Murray, Robin M; Nosarti, Chiara

    2015-03-01

    This study investigates the prevalence of eating disorder (ED) psychopathology, neuropsychological function, structural brain correlates and risk mechanisms in a prospective cohort of very preterm (VPT) young adults. We assessed ED psychopathology and neuropsychological correlates in 143 cohort individuals born at <33 weeks of gestation. Structural brain correlates and risk factors at birth, in childhood and adolescence, were investigated using prospectively collected data throughout childhood/adolescence. VPT-born individuals had high levels of ED psychopathology at age 21 years. Executive function did not correlate with ED symptomatology. VPT adults presenting with ED psychopathology had smaller grey matter volume at age 14/15 years in the left posterior cerebellum and smaller white matter volume in the fusiform gyrus bilaterally, compared with VPT adults with no ED psychopathology. Caesarean delivery predicted engaging in compensatory behaviours, and severe eating difficulty at age 14 years predicted ED symptomatology in young adulthood. VPT individuals are at risk for ED symptomatology, with evidence of associated structural alterations in posterior brain regions. Further prospective studies are needed to clarify the pathways that lead from perinatal/obstetric complications to ED and relevant neurobiological mechanisms. © 2015 The Authors. European Eating Disorders Review published by John Wiley &Sons, Ltd.

  1. Socio-Emotional Development Following Very Preterm Birth: Pathways to Psychopathology.

    PubMed

    Montagna, Anita; Nosarti, Chiara

    2016-01-01

    Very preterm birth (VPT; < 32 weeks of gestation) has been associated with an increased risk to develop cognitive and socio-emotional problems, as well as with increased vulnerability to psychiatric disorder, both with childhood and adult onset. Socio-emotional impairments that have been described in VPT individuals include diminished social competence and self-esteem, emotional dysregulation, shyness and timidity. However, the etiology of socio-emotional problems in VPT samples and their underlying mechanisms are far from understood. To date, research has focused on the investigation of both biological and environmental risk factors associated with socio-emotional problems, including structural and functional alterations in brain areas involved in processing emotions and social stimuli, perinatal stress and pain and parenting strategies. Considering the complex interplay of the aforementioned variables, the review attempts to elucidate the mechanisms underlying the association between very preterm birth, socio-emotional vulnerability and psychopathology. After a comprehensive overview of the socio-emotional impairments associated with VPT birth, three main models of socio-emotional development are presented and discussed. These focus on biological vulnerability, early life adversities and parenting, respectively. To conclude, a developmental framework is used to consider different pathways linking VPT birth to psychopathology, taking into account the interaction between medical, biological, and psychosocial factors. PMID:26903895

  2. Effect of vestibular rehabilitation on passive dynamic visual acuity

    PubMed Central

    Scherer, Matthew; Migliaccio, Americo A.; Schubert, Michael C.

    2010-01-01

    While active dynamic visual acuity (DVA) has been shown to improve with gaze stabilization exercises, we sought to determine whether DVA during passive head impulses (pDVA) would also improve following a rehabilitation course of vestibular physical therapy (VPT) in patients with unilateral and bilateral vestibular hypofunction. VPT consisted of gaze and gait stabilization exercises done as a home exercise program. Scleral search coil was used to characterize the angular vestibulo-ocular reflex (aVOR) during pDVA before and after VPT. Mean duration of VPT was 66 ± 24 days, over a total of 5 ± 1.4 outpatient visits. Two of three subjects showed improvements in pDVA with a mean reduction of 43% (LogMAR 0.58 to 0.398 and 0.92 to 0.40). Our data suggest improvements in pDVA may be due in part to improvements in aVOR velocity and acceleration gains or reduced latency of the aVOR. Each subject demonstrated a reduction in the ratio of compensatory saccades to head impulses after VPT. Preliminary data suggest that active gaze stability exercises may contribute to improvements in pDVA in some individuals. PMID:19126985

  3. Socio-Emotional Development Following Very Preterm Birth: Pathways to Psychopathology

    PubMed Central

    Montagna, Anita; Nosarti, Chiara

    2016-01-01

    Very preterm birth (VPT; < 32 weeks of gestation) has been associated with an increased risk to develop cognitive and socio-emotional problems, as well as with increased vulnerability to psychiatric disorder, both with childhood and adult onset. Socio-emotional impairments that have been described in VPT individuals include diminished social competence and self-esteem, emotional dysregulation, shyness and timidity. However, the etiology of socio-emotional problems in VPT samples and their underlying mechanisms are far from understood. To date, research has focused on the investigation of both biological and environmental risk factors associated with socio-emotional problems, including structural and functional alterations in brain areas involved in processing emotions and social stimuli, perinatal stress and pain and parenting strategies. Considering the complex interplay of the aforementioned variables, the review attempts to elucidate the mechanisms underlying the association between very preterm birth, socio-emotional vulnerability and psychopathology. After a comprehensive overview of the socio-emotional impairments associated with VPT birth, three main models of socio-emotional development are presented and discussed. These focus on biological vulnerability, early life adversities and parenting, respectively. To conclude, a developmental framework is used to consider different pathways linking VPT birth to psychopathology, taking into account the interaction between medical, biological, and psychosocial factors. PMID:26903895

  4. Vital pulp therapy using calcium-enriched mixture: An evidence-based review

    PubMed Central

    Asgary, Saeed; Ahmadyar, Maryam

    2013-01-01

    Worldwide, casecontrol studies have revealed that the treatment outcomes of root canal therapy (RCT) are generally favorable; however, the overall epidemiological success rate of RCT in the general population is relatively low. On the other hand, vitality of dental pulp is a key factor in the long-term prognosis of permanent teeth; in recent years, vital pulp therapy (VPT) has received significant consideration as it has been revealed that the inflamed pulp has the potential to heal. In this review article, the current best evidence with regard to VPT using calcium-enriched mixture (CEM) cement in human permanent/primary teeth is discussed. A strategy based on a search using keywords for CEM cement as well as VPT was applied. PMID:23716958

  5. Vital Pulp Therapy of a Mature Molar with Concurrent Hyperplastic Pulpitis, Internal Root Resorption and Periradicular Periodontitis: A Case Report

    PubMed Central

    Asgary, Saeed; Kemal Çalışkan, Mehmet

    2015-01-01

    Vital pulp therapy (VPT) of permanent mature teeth is continuously ascertaining to be a more reliable endodontic treatment. The purpose of this case report was to describe successful VPT of a mature mandibular left first molar with concurrent hyperplastic pulpitis, internal root resorption and periradicular periodontitis in a 35-year-old male patient. After complete caries removal and access cavity preparation, the dental pulp was removed from the coronal third of the roots. To protect the remaining pulp, calcium-enriched mixture (CEM) cement was placed and adapted into the cavities; the tooth was then restored with amalgam. Six months after VPT, radiographic examination showed evidence of periradicular healing. Clinically, the tooth was functional without signs and symptoms of infection/inflammation. The successful outcome of this case suggests that diseased dental pulp (i.e. irreversible pulpitis) has the potential to heal after pulp protection with CEM biocement. PMID:26523145

  6. Vital Pulp Therapy of a Symptomatic Immature Permanent Molar with Long-Term Success

    PubMed Central

    Sabbagh, Sedigheh; Sarraf Shirazi, Alireza; Eghbal, Mohammad Jafar

    2016-01-01

    Vital pulp therapy (VPT) is the preferred conservative treatment for preservation of symptomatic pulps in immature permanent teeth. The present case report summarizes VPT of an immature permanent molar with irreversible pulpitis associated with apical periodontitis in a 9-year-old boy. Cervical pulpotomy was performed and radicular pulp stumps were covered with calcium-enriched mixture (CEM) cement; the tooth was then restored with stainless steel crown. After a 50-month follow-up period, the pulpotomized molar was clinically functional and asymptomatic. Moreover, radiographic evaluation revealed evidence of complete root development as well as normal periodontal ligament around the roots. The successful outcome achieved through VPT using CEM biomaterial in the reported case suggests that this method may produce favorable outcome for vital immature permanent teeth with irreversible pulpitis and periapical disease. PMID:27790270

  7. Pain-related stress in the Neonatal Intensive Care Unit and salivary cortisol reactivity to socio-emotional stress in 3-month-old very preterm infants.

    PubMed

    Provenzi, Livio; Giusti, Lorenzo; Fumagalli, Monica; Tasca, Hilarj; Ciceri, Francesca; Menozzi, Giorgia; Mosca, Fabio; Morandi, Francesco; Borgatti, Renato; Montirosso, Rosario

    2016-10-01

    Very preterm (VPT) infants are hospitalized in the Neonatal Intensive Care Unit (NICU) and exposed to varying levels of skin-breaking procedures (pain-related stress), even in absence of severe clinical conditions. Repeated and prolonged pain exposure may alter hypothalamic-pituitary-adrenal (HPA) axis reactivity in VPT infants. During the post-discharge period, altered HPA axis reactivity has been documented in response to non-social stressors, using salivary cortisol as a biomarker. However, little is known about the effects of NICU pain-related stress on subsequent HPA axis reactivity to socio-emotional stress in infants. We examined the relationship between pain-related stress in NICU and HPA axis reactivity (i.e., salivary cortisol reactivity) to an age-appropriate socio-emotional condition in 37 healthy VPT infants compared to 53 full-term (FT) controls. The number of skin-breaking procedures was obtained across NICU stay for VPT infants. At 3 months (corrected age for prematurity), all infants participated in the maternal Face-to-Face Still-Face (FFSF) procedure, in order to assess HPA axis reactivity to socio-emotional stress (i.e., maternal unresponsiveness). VPT infants exhibited a blunted salivary cortisol reactivity, which was associated with the amount of skin-breaking procedures during NICU: greater pain-related stress predicted lower salivary cortisol reactivity, adjusting for neonatal confounders. These findings further advance our knowledge of how early exposure to pain-related stress in NICU contributes to the programming of an altered HPA axis reactivity to socio-emotional stress in 3-month-old VPT infants, even in the absence of major perinatal complications.

  8. Comparison of static and dynamic methods of treatment of anharmonicity for the vibrational study of isolated and aqueous forms of guanine

    NASA Astrophysics Data System (ADS)

    Thicoipe, Sandrine; Carbonniere, Philippe; Pouchan, Claude

    2014-01-01

    This theoretical study provides the anharmonic vibrational wavenumbers of isolated and aqueous guanine. They were performed at the DFT B3LYP/6-31+G(d,p) level of theory using two different ways for the treatment of anharmonicity: time-independent (VPT2) and time-dependent (molecular dynamics) approaches. The wavenumbers obtained are compared to experimental data for isolated and aqueous forms: the VPT2 approach is slightly better than MD, especially for the determination of stretching and wagging (NH) motions. Finally, the structural model of solvatation used for aqueous guanine which combines an explicit solvent model with a polarizable continuum model (PCM) was validated.

  9. Preterm birth and structural brain alterations in early adulthood

    PubMed Central

    Nosarti, Chiara; Nam, Kie Woo; Walshe, Muriel; Murray, Robin M.; Cuddy, Marion; Rifkin, Larry; Allin, Matthew P.G.

    2014-01-01

    Alterations in cortical development and impaired neurodevelopmental outcomes have been described following very preterm (VPT) birth in childhood and adolescence, but only a few studies to date have investigated grey matter (GM) and white matter (WM) maturation in VPT samples in early adult life. Using voxel-based morphometry (VBM) we studied regional GM and WM volumes in 68 VPT-born individuals (mean gestational age 30 weeks) and 43 term-born controls aged 19–20 years, and their association with cognitive outcomes (Hayling Sentence Completion Test, Controlled Oral Word Association Test, Visual Reproduction test of the Wechsler Memory Scale-Revised) and gestational age. Structural MRI data were obtained with a 1.5 Tesla system and analysed using the VBM8 toolbox in SPM8 with a customized study-specific template. Similarly to results obtained at adolescent assessment, VPT young adults compared to controls demonstrated reduced GM volume in temporal, frontal, insular and occipital areas, thalamus, caudate nucleus and putamen. Increases in GM volume were noted in medial/anterior frontal gyrus. Smaller subcortical WM volume in the VPT group was observed in temporal, parietal and frontal regions, and in a cluster centred on posterior corpus callosum/thalamus/fornix. Larger subcortical WM volume was found predominantly in posterior brain regions, in areas beneath the parahippocampal and occipital gyri and in cerebellum. Gestational age was associated with GM and WM volumes in areas where VPT individuals demonstrated GM and WM volumetric alterations, especially in temporal, parietal and occipital regions. VPT participants scored lower than controls on measures of IQ, executive function and non-verbal memory. When investigating GM and WM alterations and cognitive outcome scores, subcortical WM volume in an area beneath the left inferior frontal gyrus accounted for 14% of the variance of full-scale IQ (F = 12.9, p < 0.0001). WM volume in posterior corpus callosum

  10. Power Converters Secure Electronics in Harsh Environments

    NASA Technical Reports Server (NTRS)

    2013-01-01

    In order to harden power converters for the rigors of space, NASA awarded multiple SBIR contracts to Blacksburg, Virginia-based VPT Inc. The resulting hybrid DC-DC converters have proven valuable in aerospace applications, and as a result the company has generated millions in revenue from the product line and created four high-tech jobs to handle production.

  11. Anharmonic Rovibrational Calculations of Singlet Cyclic C4 Using a New Ab Initio Potential and a Quartic Force

    NASA Technical Reports Server (NTRS)

    Wang, Xiaohong; Huang, Xinchuan; Bowman, Joel M.; Lee, Timothy J.

    2013-01-01

    We report a CCSD(T)/cc-pCV5Z quartic force field (QFF) and a semi-global CCSD(T)-F12b/aug-cc-pVTZ potential energy surface (PES) for singlet, cyclic C4. Vibrational fundamentals, combinations and overtones are obtained using vibrational second-order perturbation theory (VPT2) and the vibrational configurationinteraction (VCI) approach. Agreement is within 10 cm(exp -1) between the VCI calculated fundamentals on the QFF and PES using the MULTIMODE (MM) program, and VPT2 and VCI results agree for the fundamentals. The agreement between VPT2- QFF and MM-QFF results is also good for the C4 combinations and overtones. The J = 1 and J = 2 rovibrational energies are reported from both VCI (MM) on the PES and VPT2 on the QFF calculations. The spectroscopic constants of (12)C4 and two C(sub 2v)-symmetry, single (13)C-substituted isotopologues are presented, which may help identification of cyclic C4 in future experimental analyses or astronomical observations.

  12. Inflammatory Response in Preterm and Very Preterm Newborns with Sepsis.

    PubMed

    Segura-Cervantes, Enrique; Mancilla-Ramírez, Javier; González-Canudas, Jorge; Alba, Erika; Santillán-Ballesteros, René; Morales-Barquet, Deneb; Sandoval-Plata, Gabriela; Galindo-Sevilla, Norma

    2016-01-01

    The response of the adaptive immune system is usually less intense in premature neonates than term neonates. The primary objective of this study was to determine whether immunological parameters vary between preterm (PT) neonates (≥32 weeks of gestational age) and very preterm (VPT) neonates (<32 weeks of gestational age). A cross-sectional study was designed to prospectively follow PT and VPT neonates at risk of developing sepsis. Plasma concentrations of IFN-γ, TNF-α, IL-6, IL-4, and IL-10 were detected using flow cytometry. C-reactive protein (C-RP) and the complex SC5b-9 were detected in the plasma using commercial kits. A total of 83 patients were included. The laboratory results and clinical histories showed that 26 patients had sepsis; 14 were VPT, and 12 were PT. The levels of C-RP, SC5b-9 (innate immune response mediators), and IL-10 or IL-4 (anti-inflammatory cytokines) were elevated during sepsis in both groups. IFN-γ, TNF-α, and IL-6 (proinflammatory cytokines) were differentially elevated only in PT neonates. The VPT neonates with sepsis presented increases in C-RP, SC5b-9, and anti-inflammatory cytokines but not in proinflammatory cytokines, whereas PT neonates showed increases in all studied mediators of inflammation.

  13. Anharmonic rovibrational calculations of singlet cyclic C{sub 4} using a new ab initio potential and a quartic force field

    SciTech Connect

    Wang, Xiaohong; Bowman, Joel M.; Huang, Xinchuan; Lee, Timothy J.

    2013-12-14

    We report a CCSD(T)/cc-pCV5Z quartic force field (QFF) and a semi-global CCSD(T)-F12b/aug-cc-pVTZ potential energy surface (PES) for singlet, cyclic C{sub 4}. Vibrational fundamentals, combinations, and overtones are obtained using vibrational second-order perturbation theory (VPT2) and the vibrational configuration-interaction (VCI) approach. Agreement is within 10 cm{sup −1} between the VCI calculated fundamentals on the QFF and PES using the MULTIMODE (MM) program, and VPT2 and VCI results agree for the fundamentals. The agreement between VPT2-QFF and MM-QFF results is also good for the C{sub 4} combinations and overtones. The J = 1 and J = 2 rovibrational energies are reported from both VCI (MM) on the PES and VPT2 on the QFF calculations. The spectroscopic constants of {sup 12}C{sub 4} and two C{sub 2v}-symmetry, single {sup 13}C-substituted isotopologues are presented, which may help identification of cyclic C{sub 4} in future experimental analyses or astronomical observations.

  14. Inflammatory Response in Preterm and Very Preterm Newborns with Sepsis.

    PubMed

    Segura-Cervantes, Enrique; Mancilla-Ramírez, Javier; González-Canudas, Jorge; Alba, Erika; Santillán-Ballesteros, René; Morales-Barquet, Deneb; Sandoval-Plata, Gabriela; Galindo-Sevilla, Norma

    2016-01-01

    The response of the adaptive immune system is usually less intense in premature neonates than term neonates. The primary objective of this study was to determine whether immunological parameters vary between preterm (PT) neonates (≥32 weeks of gestational age) and very preterm (VPT) neonates (<32 weeks of gestational age). A cross-sectional study was designed to prospectively follow PT and VPT neonates at risk of developing sepsis. Plasma concentrations of IFN-γ, TNF-α, IL-6, IL-4, and IL-10 were detected using flow cytometry. C-reactive protein (C-RP) and the complex SC5b-9 were detected in the plasma using commercial kits. A total of 83 patients were included. The laboratory results and clinical histories showed that 26 patients had sepsis; 14 were VPT, and 12 were PT. The levels of C-RP, SC5b-9 (innate immune response mediators), and IL-10 or IL-4 (anti-inflammatory cytokines) were elevated during sepsis in both groups. IFN-γ, TNF-α, and IL-6 (proinflammatory cytokines) were differentially elevated only in PT neonates. The VPT neonates with sepsis presented increases in C-RP, SC5b-9, and anti-inflammatory cytokines but not in proinflammatory cytokines, whereas PT neonates showed increases in all studied mediators of inflammation. PMID:27293317

  15. Inflammatory Response in Preterm and Very Preterm Newborns with Sepsis

    PubMed Central

    Segura-Cervantes, Enrique; Mancilla-Ramírez, Javier; González-Canudas, Jorge; Alba, Erika; Santillán-Ballesteros, René; Morales-Barquet, Deneb; Sandoval-Plata, Gabriela

    2016-01-01

    The response of the adaptive immune system is usually less intense in premature neonates than term neonates. The primary objective of this study was to determine whether immunological parameters vary between preterm (PT) neonates (≥32 weeks of gestational age) and very preterm (VPT) neonates (<32 weeks of gestational age). A cross-sectional study was designed to prospectively follow PT and VPT neonates at risk of developing sepsis. Plasma concentrations of IFN-γ, TNF-α, IL-6, IL-4, and IL-10 were detected using flow cytometry. C-reactive protein (C-RP) and the complex SC5b-9 were detected in the plasma using commercial kits. A total of 83 patients were included. The laboratory results and clinical histories showed that 26 patients had sepsis; 14 were VPT, and 12 were PT. The levels of C-RP, SC5b-9 (innate immune response mediators), and IL-10 or IL-4 (anti-inflammatory cytokines) were elevated during sepsis in both groups. IFN-γ, TNF-α, and IL-6 (proinflammatory cytokines) were differentially elevated only in PT neonates. The VPT neonates with sepsis presented increases in C-RP, SC5b-9, and anti-inflammatory cytokines but not in proinflammatory cytokines, whereas PT neonates showed increases in all studied mediators of inflammation. PMID:27293317

  16. Anharmonic rovibrational calculations of singlet cyclic C4 using a new ab initio potential and a quartic force field.

    PubMed

    Wang, Xiaohong; Huang, Xinchuan; Bowman, Joel M; Lee, Timothy J

    2013-12-14

    We report a CCSD(T)/cc-pCV5Z quartic force field (QFF) and a semi-global CCSD(T)-F12b/aug-cc-pVTZ potential energy surface (PES) for singlet, cyclic C4. Vibrational fundamentals, combinations, and overtones are obtained using vibrational second-order perturbation theory (VPT2) and the vibrational configuration-interaction (VCI) approach. Agreement is within 10 cm(-1) between the VCI calculated fundamentals on the QFF and PES using the MULTIMODE (MM) program, and VPT2 and VCI results agree for the fundamentals. The agreement between VPT2-QFF and MM-QFF results is also good for the C4 combinations and overtones. The J = 1 and J = 2 rovibrational energies are reported from both VCI (MM) on the PES and VPT2 on the QFF calculations. The spectroscopic constants of (12)C4 and two C2v-symmetry, single (13)C-substituted isotopologues are presented, which may help identification of cyclic C4 in future experimental analyses or astronomical observations. PMID:24329063

  17. Neural compensation in adulthood following very preterm birth demonstrated during a visual paired associates learning task

    PubMed Central

    Brittain, Philip J.; Froudist Walsh, Sean; Nam, Kie-Woo; Giampietro, Vincent; Karolis, Vyacheslav; Murray, Robin M.; Bhattacharyya, Sagnik; Kalpakidou, Anastasia; Nosarti, Chiara

    2014-01-01

    Very preterm birth (VPT; < 33 weeks of gestation) is associated with an increased risk of learning disability, which contributes to more VPT-born children repeating grades and underachieving in school. Learning problems associated with VPT birth may be caused by pathophysiological alterations in neurodevelopment resulting from perinatal brain insult; however, adaptive neuroplastic processes may subsequently occur in the developing preterm brain which ameliorate, to an extent, the potential sequelae of altered neurophysiology. Here, we used functional magnetic resonance imaging (fMRI) to compare neuronal activation in 24 VPT individuals and 22 controls (CT) in young adulthood during a learning task consisting of the encoding and subsequent recognition of repeated visual paired associates. Structural MRI data were also collected and analysed in order to explore possible structure-function associations. Whilst the two groups did not differ in their learning ability, as demonstrated by their capacity to recognize previously-seen and previously–unseen visual pairs, between-group differences in linear patterns of Blood Oxygenation Level Dependant (BOLD) activity were observed across the four repeated blocks of the task for both the encoding and recognition conditions, suggesting that the way learning takes place differs between the two groups. During encoding, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the cerebellum, the anterior cingulate gyrus, the midbrain/substantia nigra, medial temporal (including parahippocampal) gyrus and inferior and superior frontal gyri. During the recognition condition, significant between-group differences in patterns of BOLD activity were seen in clusters centred on the claustrum and the posterior cerebellum. Structural analysis revealed smaller grey matter volume in right middle temporal gyrus in VPT individuals compared to controls, however volume in this region was not

  18. Social Competence of Preschool Children Born Very Preterm

    PubMed Central

    Jones, Kelly M.; Champion, Patricia R.; Woodward, Lianne J.

    2014-01-01

    Background Relatively little is known about the early social development of children born very preterm despite clear suggestions of later interpersonal difficulties. Aims To compare the social competence of very preterm (VPT) and full term (FT) born children at age 4 and identify infant, social and family factors associated with later risk. Study design Prospective longitudinal study. Subjects A regionally representative cohort of 103 VPT (≤32 weeks gestation) children and a comparison group of 105 FT children (36-41 weeks gestation) born between 1998 and 2000. Outcome measures At corrected age 4 years, a range of parent report, observational and laboratory measures assessed children's emotional and behavioral adjustment, emotional regulation, social interactive behavior and theory of mind understanding. Extensive perinatal, social background and family functioning data were also available from birth to age 4. Results Compared to their FT peers, VPT born children had poorer emotional and behavioural adjustment, were less effective in regulating their emotions, had lower levels of positive peer play and had less synchronous interactions with their parents. Within the VPT group, predictors of poor social competence included family socioeconomic disadvantage, extreme prematurity, severity of cerebral white matter abnormalities and early childhood exposure to high levels of maternal anxiety and negative parenting. Conclusions VPT pre-schoolers are characterized by a range of subtle social difficulties likely to adversely affect their ability to establish and maintain positive relationships with others. These difficulties need to be monitored alongside other potential neurodevelopmental concerns and parents supported to actively nurture child social competence. PMID:23870752

  19. Cognitive and behavioral aspects of executive functions in children born very preterm.

    PubMed

    Ritter, Barbara Catherine; Perrig, Walter; Steinlin, Maja; Everts, Regula

    2014-03-01

    This study investigated whether children aged between 8 and 12 years born very preterm (VPT) and/or at very low birth weight (VLBW) performed lower than same-aged term-born controls in cognitive and behavioral aspects of three executive functions: inhibition, working memory, and shifting. Special attention was given to sex differences. Fifty-two VPT/VLBW children (26 girls, 50%) born in the cohort of 1998-2003 and 36 same-aged term-born children (18 girls, 50%) were recruited. As cognitive measures, children completed tasks of inhibition (Color-Word Interference Test, D-KEFS; Delis, Kaplan, & Kramer, 2001), working memory (digit span backwards, HAWIK-IV; Petermann & Petermann, 2008), and shifting (Trail Making Test, number-letter-switching, D-KEFS; Delis et al., 2001). As behavioral measures, mothers completed the Behavior Rating Inventory of Executive Function (BRIEF; Gioia, Isquith, Guy, & Kenworthy, 2000). Scales of interest were inhibit, working memory, and shift. Analyses of the cognitive aspects of executive functions revealed that VPT/VLBW children performed significantly lower than controls in the shifting task but not in the working memory and inhibition tasks. Analyses of behavioral aspects of executive functions revealed that VPT/VLBW children displayed more problems than the controls in working memory in everyday life but not in inhibition and shifting. No sex differences could be detected either in cognitive or behavioral aspects of executive functions. To conclude, cognitive and behavioral measures of executive functions were not congruent in VPT/VLBW children. In clinical practice, the combination of cognitive and behavioral instruments is required to disclose children's executive difficulties.

  20. Automatic Generation of Analytic Equations for Vibrational and Rovibrational Constants from Fourth-Order Vibrational Perturbation Theory

    NASA Astrophysics Data System (ADS)

    Matthews, Devin A.; Gong, Justin Z.; Stanton, John F.

    2014-06-01

    The derivation of analytic expressions for vibrational and rovibrational constants, for example the anharmonicity constants χij and the vibration-rotation interaction constants α^B_r, from second-order vibrational perturbation theory (VPT2) can be accomplished with pen and paper and some practice. However, the corresponding quantities from fourth-order perturbation theory (VPT4) are considerably more complex, with the only known derivations by hand extensively using many layers of complicated intermediates and for rotational quantities requiring specialization to orthorhombic cases or the form of Watson's reduced Hamiltonian. We present an automatic computer program for generating these expressions with full generality based on the adaptation of an existing numerical program based on the sum-over-states representation of the energy to a computer algebra context. The measures taken to produce well-simplified and factored expressions in an efficient manner are discussed, as well as the framework for automatically checking the correctness of the generated equations.

  1. Selective weighting of cutaneous receptor feedback and associated balance impairments following short duration space flight.

    PubMed

    Strzalkowski, Nicholas D J; Lowrey, Catherine R; Perry, Stephen D; Williams, David R; Wood, Scott J; Bent, Leah R

    2015-04-10

    The present study investigated the perception of low frequency (3 Hz) vibration on the foot sole and its relationship to standing balance following short duration space flight in nine astronauts. Both 3 Hz vibration perception threshold (VPT) and standing balance measures increased on landing day compared to pre-flight. Contrary to our hypothesis, a positive linear relationship between these measures was not observed; however astronauts with the most sensitive skin (lowest 3 Hz VPT) were found to have the largest sway on landing day. While the change in foot sole sensitivity does not appear to directly relate to standing balance control, an exploratory strategy may be employed by astronauts whose threshold to pressure information is lower. Understanding sensory adaptations and balance control has implications to improve balance control strategies following space flight and in sensory impaired populations on earth. PMID:25711797

  2. Outcomes of Different Vital Pulp Therapy Techniques on Symptomatic Permanent Teeth: A Case Series

    PubMed Central

    Asgary, Saeed; Fazlyab, Mahta; Sabbagh, Sedigheh; Eghbal, Mohammad Jafar

    2014-01-01

    In modern endodontics, vital pulp therapy (VPT) has been considered an ultra-conservative treatment modality. Based on the level of pulp preservation, VPT includes stepwise excavation, indirect pulp capping (IDPC), direct pulp capping (DPC), miniature pulpotomy (MP), partial/Cvek pulpotomy and coronal/complete pulpotomy (CP). The present article reviews the treatment outcomes of 94 permanent teeth with irreversible pulpitis treated with either IDPC (n=28), DPC (n=28), MP (n=29) or CP (n=9) using calcium-enriched mixture (CEM) cement. After a mean follow-up time of 12.3 months, 93 treated teeth were radiographic/clinically successful; only one radiographic failure was observed in the DPC group. PMID:25386213

  3. Selective weighting of cutaneous receptor feedback and associated balance impairments following short duration space flight.

    PubMed

    Strzalkowski, Nicholas D J; Lowrey, Catherine R; Perry, Stephen D; Williams, David R; Wood, Scott J; Bent, Leah R

    2015-04-10

    The present study investigated the perception of low frequency (3 Hz) vibration on the foot sole and its relationship to standing balance following short duration space flight in nine astronauts. Both 3 Hz vibration perception threshold (VPT) and standing balance measures increased on landing day compared to pre-flight. Contrary to our hypothesis, a positive linear relationship between these measures was not observed; however astronauts with the most sensitive skin (lowest 3 Hz VPT) were found to have the largest sway on landing day. While the change in foot sole sensitivity does not appear to directly relate to standing balance control, an exploratory strategy may be employed by astronauts whose threshold to pressure information is lower. Understanding sensory adaptations and balance control has implications to improve balance control strategies following space flight and in sensory impaired populations on earth.

  4. A Review on Vital Pulp Therapy in Primary Teeth

    PubMed Central

    Parisay, Iman; Ghoddusi, Jamileh; Forghani, Maryam

    2015-01-01

    Maintaining deciduous teeth in function until their natural exfoliation is absolutely necessary. Vital pulp therapy (VPT) is a way of saving deciduous teeth. The most important factors in success of VPT are the early diagnosis of pulp and periradicular status, preservation of the pulp vitality and proper vascularization of the pulp. Development of new biomaterials with suitable biocompatibility and seal has changed the attitudes towards preserving the reversible pulp in cariously exposed teeth. Before exposure and irreversible involvement of the pulp, indirect pulp capping (IPC) is the treatment of choice, but after the spread of inflammation within the pulp chamber and establishment of irreversible pulpitis, removal of inflamed pulp tissue is recommended. In this review, new concepts in preservation of the healthy pulp tissue in deciduous teeth and induction of the reparative dentin formation with new biomaterials instead of devitalization and the consequent destruction of vital tissues are discussed. PMID:25598803

  5. FTIR, FT-Raman and UV-Vis spectral studies of D-tyrosine molecule

    NASA Astrophysics Data System (ADS)

    Bhat, Sheeraz Ahmad; Ahmad, Shabbir

    2016-02-01

    In the present work, experimental and theoretical studies on the structure, vibrational spectra and electronic spectra of D-tyrosine molecule are reported. The FTIR (4000-400 cm-1) and FT-Raman (4000-50 cm-1) spectra were recorded and analysed using anharmonic frequency calculations at PT2-VSCF and VPT2 levels in gas and solution phases. The solute-solvent interactions were treated using the integral equation formalism of the polarisation continuum model (IEF-PCM). The calculated anharmonic frequencies were compared with the experimental ones. It was found that PT2-VSCF anharmonic frequencies are closer to the experimental data. The VPT2 frequencies in gas and solution phases have small differences. The magnitudes of coupling between pair of modes were also computed. In addition, studies on the excitation energies, oscillator strengths, HOMO and LUMO energies and MEP of D-tyrosine at TD-DFT level are also reported.

  6. Vibrational Corrections to Molecular Properties: Second-Order Vibrational Perturbation Theory VS Variational Computations

    NASA Astrophysics Data System (ADS)

    Harding, Michael E.; Vázquez, Juana; Stanton, John F.; Diezemann, Gregor; Gauss, Jürgen

    2011-06-01

    For a small set of linear and non-linear molecules, a detailed comparison of two different procedures for predicting vibrationally averaged molecular properties, i.e., second-order vibrational perturbation theory (VPT2) and a variational approach, is carried out. Results for vibrational corrections to dipole and quadrupole moments, nuclear quadrupole moments, static electric-dipole polarizabilities, NMR chemical shielding tensors, nuclear spin-rotation tensors, magnetizabilities, and rotational g-tensors are reported.

  7. Rovibrational Spectroscopic Constants and Fundamental Vibrational Frequencies for Isotopologues of Cyclic and Bent Singlet HC2N isomers

    NASA Technical Reports Server (NTRS)

    Inostroza, Natalia; Fortenberry, Ryan C.; Huang, Xinchuan; Lee, Timothy J.

    2013-01-01

    Through established, highly-accurate ab initio quartic force fields (QFFs), a complete set of fundamental vibrational frequencies, rotational constants, and rovibrational coupling and centrifugal distortion constants have been determined for both the cyclic 1(sup 1) 1A' and bent 2(sup 1)A' DCCN, H(C13)CCN, HC(C-13)N, and HCC(N-15) isotopologues of HCCN. Spectroscopic constants are computed for all isotopologues using second-order vibrational perturbation theory (VPT2), and the fundamental vibrational frequencies are computed with VPT2 and vibrational configuration interaction (VCI) theory. Agreement between VPT2 and VCI results is quite good with the fundamental vibrational frequencies of the bent isomer isotopologues in accord to within a 0.1 to 3.2 / cm range. Similar accuracies are present for the cyclic isomer isotopologues. The data generated here serve as a reference for astronomical observations of these closed-shell, highly-dipolar molecules using new, high-resolution telescopes and as reference for laboratory studies where isotopic labeling may lead to elucidation of the formation mechanism for the known interstellar molecule: X 3A0 HCCN.

  8. Rovibrational spectroscopic constants and fundamental vibrational frequencies for isotopologues of cyclic and bent singlet HC{sub 2}N isomers

    SciTech Connect

    Inostroza, Natalia; Fortenberry, Ryan C.; Lee, Timothy J.; Huang, Xinchuan

    2013-12-01

    Through established, highly accurate ab initio quartic force fields, a complete set of fundamental vibrational frequencies, rotational constants, and rovibrational coupling and centrifugal distortion constants have been determined for both the cyclic 1 {sup 1} A' and bent 2 {sup 1} A' DCCN, H{sup 13}CCN, HC{sup 13}CN, and HCC{sup 15}N isotopologues of HCCN. Spectroscopic constants are computed for all isotopologues using second-order vibrational perturbation theory (VPT2), and the fundamental vibrational frequencies are computed with VPT2 and vibrational configuration interaction (VCI) theory. Agreement between VPT2 and VCI results is quite good, with the fundamental vibrational frequencies of the bent isomer isotopologues in accord to within a 0.1-3.2 cm{sup –1} range. Similar accuracies are present for the cyclic isomer isotopologues. The data generated here serve as a reference for astronomical observations of these closed-shell, highly dipolar molecules using new, high-resolution telescopes and as reference for laboratory studies where isotopic labeling may lead to elucidation of the formation mechanism for the known interstellar molecule: X {sup 3} A' HCCN.

  9. Outcomes of vital pulp therapy in permanent teeth with different medicaments based on review of the literature

    PubMed Central

    Akhlaghi, Najmeh; Khademi, Abbasali

    2015-01-01

    Vital pulp therapy (VPT) is a biologic and conservative treatment modality to preserve the vitality and function of the coronal or remaining radicular pulp tissue in vital permanent teeth. A search was conducted via the Cochrane database, PubMed, MEDLINE, and Ovid for any articles with the criteria for “pulp-capping,” or “pulp-capping materials” and “VPT outcomes” from 1978 to mid 2014. All articles were evaluated and the valid papers were selected. The outcomes of various VPT techniques, including indirect pulp treatment, direct pulp treatment, partial pulpotomy, and complete pulpotomy in vital permanent teeth were extracted. Although various studies have different research approach, most studies noted a favorable treatment outcome. Mineral trioxide aggregate (MTA) appears to be more effective than calcium hydroxide (Ca(OH)2) for maintaining long-term pulp vitality after indirect and direct pulp-capping. However, it seems that the success rate for partial pulpotomy and pulpotomy with Ca(OH)2 is similar to MTA. PMID:26604953

  10. Balancing accuracy and efficiency in selecting vibrational configuration interaction basis states using vibrational perturbation theory

    NASA Astrophysics Data System (ADS)

    Sibaev, Marat; Crittenden, Deborah L.

    2016-08-01

    This work describes the benchmarking of a vibrational configuration interaction (VCI) algorithm that combines the favourable computational scaling of VPT2 with the algorithmic robustness of VCI, in which VCI basis states are selected according to the magnitude of their contribution to the VPT2 energy, for the ground state and fundamental excited states. Particularly novel aspects of this work include: expanding the potential to 6th order in normal mode coordinates, using a double-iterative procedure in which configuration selection and VCI wavefunction updates are performed iteratively (micro-iterations) over a range of screening threshold values (macro-iterations), and characterisation of computational resource requirements as a function of molecular size. Computational costs may be further reduced by a priori truncation of the VCI wavefunction according to maximum extent of mode coupling, along with discarding negligible force constants and VCI matrix elements, and formulating the wavefunction in a harmonic oscillator product basis to enable efficient evaluation of VCI matrix elements. Combining these strategies, we define a series of screening procedures that scale as O ( Nmode 6 ) - O ( Nmode 9 ) in run time and O ( Nmode 6 ) - O ( Nmode 7 ) in memory, depending on the desired level of accuracy. Our open-source code is freely available for download from http://www.sourceforge.net/projects/pyvci-vpt2.

  11. A novel, non-invasive method of respiratory monitoring for use with stereotactic procedures

    PubMed Central

    Cleary, Daniel R.; Phillips, Ryan S.; Wallisch, Michael; Heinricher, Mary M.

    2012-01-01

    Accurate monitoring of respiration is often needed for neurophysiological studies, as either a dependent experimental variable or an indicator of physiological state. Current options for respiratory monitoring of animals held in a stereotaxic frame include EMG recordings, pneumotachograph measurements, inductance-plethysmography, whole-body plethysmography (WBP), and visual monitoring. While powerful, many of these methods prevent access to the animal’s body, interfere with experimental manipulations, or require deep anesthesia and additional surgery. For experiments where these issues may be problematic, we developed a non-invasive method of recording respiratory parameters specifically for use with animals held in a stereotaxic frame. This system, ventilation pressure transduction (VPT), measures variations in pressure at the animal’s nostril from inward and outward airflow during breathing. These pressure changes are detected by a sensitive pressure transducer, then filtered and amplified. The output is an analog signal representing each breath. VPT was validated against WBP using 10% carbon dioxide and systemic morphine (4 mg/kg) challenges in lightly anesthetized animals. VPT accurately represented breathing rate and tidal volume changes under both baseline and challenge conditions. This novel technique can therefore be used to measure respiratory rate and relative tidal volume when stereotaxic procedures are needed for neuronal manipulations and recording. PMID:22771713

  12. Alpha-linolenic acid intake prevents endothelial dysfunction in high-fat diet-fed streptozotocin rats and underlying mechanisms.

    PubMed

    Zhang, Wei; Fu, Fang; Tie, Ru; Liang, Xiangyan; Tian, Fei; Xing, Wenjuan; Li, Jia; Ji, Lele; Xing, Jinliang; Sun, Xin; Zhang, Haifeng

    2013-11-01

    Hintergrund: Die endotheliale Dysfunktion ist ein wichtiger Faktor in der Pathogenenese von diabetes- assoziierten Gefäßkomplikationen. Alpha-Linolensäure (ALA) kann die flußvermittelte Dilatation der diabetischen Arterie vier Stunden postprandial erhöhen. Es ist aber weitgehend unklar, ob eine chronische ALA Supplementierung eine endotheliale Dysfunktion verhüten kann. Material und Methoden: Streptozotozin (HFD-STZ) Ratten unter hochdosierter Fettdiät (HFD-STZ) stellen ein Tiermodell für den Typ 2 Diabetes (T2DM) dar. Altersgleiche normale und HFD-STZ Ratten bekamen randomisiert eine normale Diät oder ALA (500 mg/kg pro Tag). Nach 5 Wochen wurde die endotheliale Dysfunktion gemessen. Ergebnisse: Diabetes verursachte eine signifikante endotheliale Dysfunktion (maximale Vasorelaxation auf Azetylcholin) in aortalen Segmenten. ALA Aufnahme milderte die endotheliale Dysfunktion. Superoxide Produktion and Peroxynitrite (ONOO-) Bildung waren unter ALA Supplementierung in den diabetischen Gefäßsegmenten vermindert. Bemerkenswerterweise verstärkte die ALA Aufnahme eNOS, hemmte aber die iNOS Aktivität in diabetischen Gefäßen. Darüber hinaus steigerte ALA die Aufnahme der eNOS Phosphorylation signifikant. Andererseits waren gp91phox und iNOS Überexpression moderat bei ALA Aufnahme reduziert. Schlussfolgerungen: ALA wirkt präventiv auf eine diabetes-induzierte endotheliale Dysfunktion, indem es die eNOS Aktivität verstärkt und den oxidativen/nitrativen Stress durch Hemmung der iNOS und NADPH Oxidase Expression und ONOO-Production mildert.

  13. Free Thyroxine Levels After Very Preterm Birth and Neurodevelopmental Outcomes at Age 7 Years

    PubMed Central

    Scratch, Shannon E.; Hunt, Rodney W.; Thompson, Deanne K.; Ahmadzai, Zohra M.; Doyle, Lex W.; Inder, Terrie E.

    2014-01-01

    BACKGROUND AND OBJECTIVES: Preterm infants commonly have transient hypothyroxinemia of prematurity after birth, which has been associated with deficits in general intellectual functioning, memory, attention, and academic achievement. However, research has predominantly focused on thyroxine levels in the first 2 weeks of life and outcomes are limited to the preschool period. Our objective was to evaluate the relationships between free thyroxine (fT4) levels over the first 6 weeks after very preterm (VPT) birth with cognitive functioning and brain development at age 7 years. METHODS: A total of 83 infants born VPT (<30 weeks’ gestation) had fT4 concentrations measured postnatally and 2- and 6-week area under the curve (AUC) summary measures were calculated. Follow-up at age 7 years included a neuropsychological assessment and brain MRI. Univariable and multivariable regression modeling was used where AUC for fT4 was the main predictor of neurodevelopmental outcome at age 7 years. RESULTS: Multivariable modeling revealed that higher, not lower, postnatal fT4 levels (2-week AUC) were associated with poorer cognitive performances at age 7 years on tasks of verbal learning (P = .02), verbal memory (P = .03), and simple reaction time (P < .001). A similar pattern of results was found when the 6-week AUC was examined. No significant associations between postnatal fT4 levels and brain volumes at age 7 years were identified. CONCLUSIONS: Results are contradictory to previous observations and suggest that after adjustment for confounders, higher postnatal fT4 levels in VPT infants, rather than lower levels, may be a marker of adverse neuropsychological development in childhood. PMID:24685955

  14. Oxidative stress predicts progression of peripheral and cardiac autonomic nerve dysfunction over 6 years in diabetic patients.

    PubMed

    Ziegler, Dan; Buchholz, Stefanie; Sohr, Christoph; Nourooz-Zadeh, Jaffar; Roden, Michael

    2015-02-01

    Oxidative stress is implicated in the pathogenesis of experimental diabetic neuropathy, but prospective studies in diabetic patients are lacking. We aimed to evaluate whether the plasma levels of various biomarkers of oxidative stress predict the progression of diabetic neuropathy and mortality over 6 years. We followed 89 diabetic patients aged 54 ± 14 years (59 % with polyneuropathy), 72 of whom underwent nerve function reassessment after 6.2 ± 0.8 years, whereas 17 died after 4.2 ± 1.0 years. Plasma markers of oxidative stress at baseline included superoxide anion, hypochlorous acid, peroxynitrite, 8-iso-prostaglandin F2α, vitamin E/lipid ratio, and vitamin C. Neuropathy was assessed by symptoms and deficits, motor and sensory nerve conduction velocity (MNCV, SNCV), vibration perception thresholds (VPT), thermal detection thresholds, and heart rate variability (HRV). Despite a reduction in HbA1c by 1.4 ± 1.6 % (p < 0.001), median SNCV, sural SNCV, peroneal MNCV, malleolar VPT, and warm TDT deteriorated after 6 years (all p < 0.05). In multivariate models, increased superoxide generation was associated with a decline in median SNCV (β = -0.997; p = 0.036) and deterioration in HRV at rest (OR 1.63 [95 % CI 1.09-2.44]; p = 0.017) over 6 years. Low vitamin E/lipid ratio tended to predict a decrease in peroneal MNCV (β = 0.781; p = 0.057) and an increase in malleolar VPT (β = -0.725; p = 0.077). Plasma superoxide generation was associated with an increased risk of mortality (HR 23.2 [95 % CI 1.05-513]; p = 0.047). In conclusion, increased plasma superoxide generation predicted the decline in sensory and cardiac autonomic nerve function and mortality over 6 years in diabetic patients, but larger studies are required for confirmation.

  15. Evaluation of children's dental anxiety levels at a kindergarten and at a dental clinic.

    PubMed

    Kilinç, Gulser; Akay, Aynur; Eden, Ece; Sevinç, Nilgün; Ellidokuz, Hülya

    2016-01-01

    This study evaluated the dental anxiety levels of preschool children at a kindergarten and at a dental clinic. The anxiety levels of ninety 4-6-year-old (4.99 ± 0.81) preschool children were evaluated according to pulse rates, the facial image scale (FIS), the Venham picture test (VPT), and the Frankl behavior rating scale. The children's mothers were asked to complete the state-trait anxiety inventory (STAI) forms 1 and 2 (STAI 2 and STAI 2). The sample t-test, Mann-Whitney U test, and Pearson's correlation test were used. A statistically significant difference was observed between the children's pulse rates when measured at the dental clinic and those when measured at the kindergarten (p < 0.001). Although the results were not statistically significant, more negative facial expressions were observed in the children at the dental clinic than in those at the kindergarten when assessed using FIS and VPT (p = 0.090 and p = 0.108, respectively). There was a statistically significant correlation between the transient anxiety levels (STAI 1) of mothers and the VPT scores of their children evaluated at the dental clinic (r = 0.506, p < 0.001). The continuous anxiety level of the mothers of males was found to be significantly higher (p = 0.033) than that of the mothers of females (STAI 2). Although the children had been informed about dentistry and were introduced to a dentist at the kindergarten, their anxiety levels seemingly increased as they arrived at the dental clinic. The significant increase observed in the children's pulse rates was a physical indicator that their anxiety levels had increased. It can be concluded that the children felt more anxious at the dental clinic that at the kindergarten. PMID:27556551

  16. Evaluation of children's dental anxiety levels at a kindergarten and at a dental clinic.

    PubMed

    Kilinç, Gulser; Akay, Aynur; Eden, Ece; Sevinç, Nilgün; Ellidokuz, Hülya

    2016-08-18

    This study evaluated the dental anxiety levels of preschool children at a kindergarten and at a dental clinic. The anxiety levels of ninety 4-6-year-old (4.99 ± 0.81) preschool children were evaluated according to pulse rates, the facial image scale (FIS), the Venham picture test (VPT), and the Frankl behavior rating scale. The children's mothers were asked to complete the state-trait anxiety inventory (STAI) forms 1 and 2 (STAI 2 and STAI 2). The sample t-test, Mann-Whitney U test, and Pearson's correlation test were used. A statistically significant difference was observed between the children's pulse rates when measured at the dental clinic and those when measured at the kindergarten (p < 0.001). Although the results were not statistically significant, more negative facial expressions were observed in the children at the dental clinic than in those at the kindergarten when assessed using FIS and VPT (p = 0.090 and p = 0.108, respectively). There was a statistically significant correlation between the transient anxiety levels (STAI 1) of mothers and the VPT scores of their children evaluated at the dental clinic (r = 0.506, p < 0.001). The continuous anxiety level of the mothers of males was found to be significantly higher (p = 0.033) than that of the mothers of females (STAI 2). Although the children had been informed about dentistry and were introduced to a dentist at the kindergarten, their anxiety levels seemingly increased as they arrived at the dental clinic. The significant increase observed in the children's pulse rates was a physical indicator that their anxiety levels had increased. It can be concluded that the children felt more anxious at the dental clinic that at the kindergarten.

  17. Static balance function in children with a history of preterm birth

    PubMed Central

    Eshaghi, Zahra; Jafari, Zahra; Jalaie, Shohreh

    2015-01-01

    Background: The incomplete maturation of brain in preterm children results in long-term neurodevelopmental impairment. This study aimed to investigate the static balance function in children with a history of preterm birth. Methods: Participants were 31 preterm children including 21 moderately preterm (MPT), 10 very preterm (VPT), and 20 term children aged 5.5 and 6.5 years. The cervical vestibular-evoked myogenic potential (cVEMP) test and four static balance subscales of BOT-2 were performed. Results: The VPT children showed a significant increase in P1 and N1 wave latencies in cVEMP test compared to those in the term children (p= 0.041). Mean scores in the four static balance subscales of BOT-2 were significantly lower in the preterm children compared to those in the term children (p= 0.025). The P1 wave latency (p= 0.003) and mean score of standing on a balance beam with open eyes (p= 0.039) were significantly lower in the VPT children compared to those in the MPT children. A significant correlation was observed between the mean score in exercise 4 (standing on one leg on a balance beam with closed eyes) of static balance subscales of BOT-2 and P1 (r= -0.267, p= 0.036) and N1 (r= -0.304, p= 0.016) wave latencies of cVEMP. Conclusion: The longer latency of cVEMP waves along with a poor performance of children with a history of preterm birth suggests a possible defect in central vestibular pathway. PMID:26913273

  18. Reinvestigation of spectroscopic properties for ammonia-hydrogen halide complexes from Car-Parrinello Molecular Dynamics

    NASA Astrophysics Data System (ADS)

    Panek, Paweł; Biczysko, Malgorzata; Latajka, Zdzisław

    2011-09-01

    Infrared spectra of ammonia-hydrogen chloride and hydrogen bromide were obtained from Car-Parrinello Molecular Dynamics simulations. Proton distribution and proton transfer free energy along hydrogen bond together with hydrogen bond angle distribution during the simulations have been calculated. VPT2 and VSCF anharmonic vibrational frequencies have been also computed at DFT (BLYP) and post-Hartree-Fock (MP2) levels. Hydrogen bond properties obtained from MD simulations show good agreement with previously reported static results. In the absence of experimental gas phase infrared spectra, reported results shed further light on the spectroscopic properties of ammonia-hydrogen halides molecular complexes.

  19. Predicting the structure and vibrational frequencies of ethylene using harmonic and anharmonic approaches at the Kohn-Sham complete basis set limit.

    PubMed

    Buczek, Aneta; Kupka, Teobald; Broda, Małgorzata A; Żyła, Adriana

    2016-01-01

    In this work, regular convergence patterns of the structural, harmonic, and VPT2-calculated anharmonic vibrational parameters of ethylene towards the Kohn-Sham complete basis set (KS CBS) limit are demonstrated for the first time. The performance of the VPT2 scheme implemented using density functional theory (DFT-BLYP and DFT-B3LYP) in combination with two Pople basis sets (6-311++G** and 6-311++G(3df,2pd)), the polarization-consistent basis sets pc-n, aug-pc-n, and pcseg-n (n = 0, 1, 2, 3, 4), and the correlation-consistent basis sets cc-pVXZ and aug-cc-pVXZ (X = D, T, Q, 5, 6) was tested.The BLYP-calculated harmonic frequencies were found to be markedly closer than the B3LYP-calculated harmonic frequencies to the experimentally derived values, while the calculated anharmonic frequencies consistently underestimated the observed wavenumbers. The different basis set families gave very similar estimated values for the CBS parameters. The anharmonic frequencies calculated with B3LYP/aug-pc-3 were consistently significantly higher than those obtained with the pc-3 basis set; applying the aug-pcseg-n basis set family alleviated this problem. Utilization of B3LYP/aug-pcseg-n basis sets instead of B3LYP/aug-cc-pVXZ, which is computationally less expensive, is suggested for medium-sized molecules. Harmonic BLYP/pc-2 calculations produced fairly accurate ethylene frequencies. Graphical Abstract In this study, the performance of the VPT2 scheme implemented using density functional theory (DFT-BLYP and DFT-B3LYP) in combination with the polarization-consistent basis sets pc-n, aug-pc-n, and pcseg-n (n = 0, 1, 2, 3, 4), and the correlation-consistent basis sets cc-pVXZ and aug-cc-pVXZ (X = D, T, Q, 5, and 6) was tested. For the first time, we demonstrated regular convergence patterns of the structural, harmonic, and VPT2-calculated anharmonic vibrational parameters of ethylene towards the Kohn-Sham complete basis set (KS CBS) limit.

  20. A comparison of ZnO films deposited on indium tin oxide and soda lime glass under identical conditions

    SciTech Connect

    Deka, Angshuman; Nanda, Karuna Kar

    2013-06-15

    ZnO films have been grown via a vapour phase transport (VPT) on soda lime glass (SLG) and indium-tin oxide (ITO) coated glass. ZnO film on ITO had traces of Zn and C which gives them a dark appearance while that appears yellowish-white on SLG. X-ray photoelectron spectroscopy studies confirm the traces of C in the form of C-O. The photoluminescence studies reveal a prominent green luminescence band for ZnO film on ITO.

  1. The donor OH stretching-libration dynamics of hydrogen-bonded methanol dimers in cryogenic matrices.

    PubMed

    Heger, M; Andersen, J; Suhm, M A; Wugt Larsen, R

    2016-02-01

    FTIR spectra of the methanol dimer trapped in neon matrices are presented. The fundamental, overtone and combination bands involving the donor OH libration and stretching motions were observed in order to extract relevant anharmonicity constants. We find a stretching-libration coupling constant of +43(5) cm(-1) and a diagonal librational anharmonicity constant of -71(5) cm(-1). The spectra are compared to a number of VPT2 calculations and a torsionally localized monomer model in order to enhance previous explanations of the observable OH stretching red-shift upon dimerization. PMID:26763101

  2. Using vapor phase tomography to measure the spatial distribution of vapor concentrations and flux for vadose-zone VOC sources.

    PubMed

    Mainhagu, J; Morrison, C; Brusseau, M L

    2015-01-01

    A test was conducted at a chlorinated-solvent contaminated site in Tucson, AZ, to evaluate the effectiveness of vapor-phase tomography (VPT) for characterizing the distribution of volatile organic contaminants (VOC) in the vadose zone. A soil vapor extraction (SVE) system has been in operation at the site since 2007. Vapor concentration and vacuum pressure were measured at four different depths in each of the four monitoring wells surrounding the extraction well. The test provided a 3D characterization of local vapor concentrations under induced-gradient conditions. Permeability data obtained from analysis of borehole logs were used along with pressure and the vapor-concentration data to determine VOC mass flux within the test domain. A region of higher mass flux was identified in the deepest interval of the S-SW section of the domain, indicating the possible location of a zone with greater contaminant mass. These results are consistent with the TCE-concentration distribution obtained from sediment coring conducted at the site. In contrast, the results of a standard soil gas survey did not indicate the presence of a zone with greater contaminant mass. These results indicate that the VPT test provided a robust characterization of VOC concentration and flux distribution at the site.

  3. Using Vapor Phase Tomography to Measure the Spatial Distribution of Vapor Concentrations and Flux for Vadose-Zone VOC Sources

    NASA Astrophysics Data System (ADS)

    Mainhagu, J.; Brusseau, M. L. L.; Morrison, C. N.

    2015-12-01

    A test was conducted at a chlorinated-solvent contaminated site in Tucson, AZ, to evaluate the effectiveness of vapor-phase tomography (VPT) for characterizing the distribution of volatile organic contaminants (VOC) in the vadose zone. A soil vapor extraction (SVE) system has been in operation at the site since 2007. Vapor concentration and vacuum pressure were measured at four different depths in each of the four monitoring wells surrounding the extraction well. The test provided a 3D characterization of local vapor concentrations under induced-gradient conditions. Permeability data obtained from analysis of borehole logs were used along with pressure and the vapor-concentration data to determine VOC mass flux within the test domain. A region of higher mass flux was identified in the deepest interval of the S-SW section of the domain, indicating the possible location of a zone with greater contaminant mass. These results are consistent with the TCE-concentration distribution obtained from sediment coring conducted at the site. In contrast, the results of a standard soil gas survey did not indicate the presence of a zone with greater contaminant mass. These results indicate that the VPT test provided a robust characterization of VOC concentration and flux distribution at the site.

  4. Using vapor phase tomography to measure the spatial distribution of vapor concentrations and flux for vadose-zone VOC sources

    NASA Astrophysics Data System (ADS)

    Mainhagu, J.; Morrison, C.; Brusseau, M. L.

    2015-06-01

    A test was conducted at a chlorinated-solvent contaminated site in Tucson, AZ, to evaluate the effectiveness of vapor-phase tomography (VPT) for characterizing the distribution of volatile organic contaminants (VOC) in the vadose zone. A soil vapor extraction (SVE) system has been in operation at the site since 2007. Vapor concentration and vacuum pressure were measured at four different depths in each of the four monitoring wells surrounding the extraction well. The test provided a 3D characterization of local vapor concentrations under induced-gradient conditions. Permeability data obtained from analysis of borehole logs were used along with pressure and the vapor-concentration data to determine VOC mass flux within the test domain. A region of higher mass flux was identified in the deepest interval of the S-SW section of the domain, indicating the possible location of a zone with greater contaminant mass. These results are consistent with the TCE-concentration distribution obtained from sediment coring conducted at the site. In contrast, the results of a standard soil gas survey did not indicate the presence of a zone with greater contaminant mass. These results indicate that the VPT test provided a robust characterization of VOC concentration and flux distribution at the site.

  5. Using Vapor Phase Tomography to Measure the Spatial Distribution of Vapor Concentrations and Flux for Vadose-zone VOC Sources

    PubMed Central

    Mainhagu, J.; Morrison, C.; Brusseau, M.L.

    2015-01-01

    A test was conducted at a chlorinated-solvent contaminated site in Tucson, AZ, to evaluate the effectiveness of vapor-phase tomography (VPT) for characterizing the distribution of volatile organic contaminants (VOC) in the vadose zone. A soil vapor extraction (SVE) system has been in operation at the site since 2007. Vapor concentration and vacuum pressure were measured at four different depths in each of four monitoring wells surrounding the extraction well. The test provided a 3D characterization of local vapor concentrations under induced-gradient conditions. Permeability data obtained from analysis of borehole logs were combined with the vapor-concentration data to determine VOC mass flux within the test domain. A region of higher mass flux was identified in the deepest interval of the S-SW section of the domain, indicating the possible location of a zone with greater contaminant mass. These results are consistent with the TCE-concentration distribution obtained from sediment coring conducted at the site. In contrast, the results of a standard soil gas survey did not indicate the presence of a zone with greater contaminant mass. These results indicate that the VPT test provided a robust characterization of VOC concentration and flux distribution at the site. PMID:25835545

  6. [Feeding habits of immature individuals of Ephemeroptera, Plecoptera, and Trichoptera from middle reaches of a tropical mountain stream].

    PubMed

    Guzmán-Soto, Cristian José; Tamarís-Turizo, Cesar Enrique

    2014-04-01

    Morphological and behavioral aspects of insects allow their grouping in trophic guilds and represent their dependence on food resources. We determined the feeding habits of immature organisms of Ephemeroptera, Plecoptera, and Trichoptera (EPT) from the middle reaches of Gaira stream (Sierra Nevada de Santa Marta, Colombia), using gut content analysis. We identified 13 EPT genera, but only ten were analyzed for a total of 100 organisms. We describe six food items: animal parts (AP), vascular plant tissue (VPT), microalgae (M), fungi (F), coarse particulate organic matter (CPOM) and fine particulate organic matter (FPOM). Baetodes was determined to be a collector-scraper, since FPOM represented 46.6% of food content, followed by F (38.4%). Chimarra, Leptohyphes, Lachlania, and Thraulodes were categorized as collectors with average proportions of FPOM 86.8%, 93.1%, 93.1% and 93.7%, respectively. Phylloicus, Smicridea and Leptonema were main consumers of VPT and CPOM with proportions of 76.3%, 54.6%, and 62.4%, respectively; while ratios of FPOM were 22.3%, 38.8%, and 32.9%, respectively. While all are detritivores, Phylloicus is functionally classified as shredders and Smicridea and Leptonema as collectors. Atopsyche and Anacroneuria were the only taxa in which AP were observed in high proportions, 57.9% and 58.2%, respectively, for that reason they were classified as predators. The organisms examined consume a wide variability of resources. PMID:25189077

  7. ZnO nanorod growth by plasma-enhanced vapor phase transport with different growth durations

    SciTech Connect

    Kim, Chang-Yong; Oh, Hee-bong; Ryu, Hyukhyun; Yun, Jondo; Lee, Won-Jae

    2014-09-01

    In this study, the structural properties of ZnO nanostructures grown by plasma-enhanced vapor phase transport (PEVPT) were investigated. Plasma-treated oxygen gas was used as the oxygen source for the ZnO growth. The structural properties of ZnO nanostructures grown for different durations were measured by scanning electron microscopy, x-ray diffraction, and transmission electron microscopy. The authors comprehensively analyzed the growth of the ZnO nanostructures with different growth durations both with and without the use of plasma-treated oxygen gas. It was found that PEVPT has a significant influence on the growth of the ZnO nanorods. PEVPT with plasma-treated oxygen gas facilitated the generation of nucleation sites, and the resulting ZnO nanorod structures were more vertical than those prepared by conventional VPT without plasma-treated oxygen gas. As a result, the ZnO nanostructures grown using PEVPT showed improved structural properties compared to those prepared by the conventional VPT method.

  8. Testosterone Plus Low-Intensity Physical Training in Late Life Improves Functional Performance, Skeletal Muscle Mitochondrial Biogenesis, and Mitochondrial Quality Control in Male Mice

    PubMed Central

    Guo, Wen; Wong, Siu; Li, Michelle; Liang, Wentao; Liesa, Marc; Serra, Carlo; Jasuja, Ravi; Bartke, Andrzej; Kirkland, James L.; Shirihai, Orian; Bhasin, Shalender

    2012-01-01

    Testosterone supplementation increases muscle mass in older men but has not been shown to consistently improve physical function and activity. It has been hypothesized that physical exercise is required to induce the adaptations necessary for translation of testosterone-induced muscle mass gain into functional improvements. However, the effects of testosterone plus low intensity physical exercise training (T/PT) on functional performance and bioenergetics are unknown. In this pilot study, we tested the hypothesis that combined administration of T/PT would improve functional performance and bioenergetics in male mice late in life more than low-intensity physical training alone. 28-month old male mice were randomized to receive T/PT or vehicle plus physical training (V/PT) for 2 months. Compare to V/PT control, administration of T/PT was associated with improvements in muscle mass, grip strength, spontaneous physical movements, and respiratory activity. These changes were correlated with increased mitochondrial DNA copy number and expression of markers for mitochondrial biogenesis. Mice receiving T/PT also displayed increased expression of key elements for mitochondrial quality control, including markers for mitochondrial fission-and-fusion and mitophagy. Concurrently, mice receiving T/PT also displayed increased expression of markers for reduced tissue oxidative damage and improved muscle quality. Conclusion: Testosterone administered with low-intensity physical training improves grip strength, spontaneous movements, and respiratory activity. These functional improvements were associated with increased muscle mitochondrial biogenesis and improved mitochondrial quality control. PMID:23240002

  9. Semi-quartic force fields retrieved from multi-mode expansions: Accuracy, scaling behavior, and approximations

    SciTech Connect

    Ramakrishnan, Raghunathan; Rauhut, Guntram

    2015-04-21

    Semi-quartic force fields (QFF) rely on a Taylor-expansion of the multi-dimensional Born-Oppenheimer potential energy surface (PES) and are frequently used within the calculation of anharmonic vibrational frequencies based on 2nd order vibrational perturbation theory (VPT2). As such they are usually determined by differentiation of the electronic energy with respect to the nuclear coordinates. Alternatively, potential energy surfaces can be expanded in terms of multi-mode expansions, which typically do not require any derivative techniques. The computational effort to retrieve QFF from size-reduced multi-mode expansions has been studied and has been compared with standard Taylor-expansions. As multi-mode expansions allow for the convenient introduction of subtle approximations, these will be discussed in some detail. In addition, a preliminary study about the applicability of a generalized Duschinsky transformation to QFFs is provided. This transformation allows for the efficient evaluation of VPT2 frequencies of isotopologues from the PES of the parent compound and thus avoids the recalculation of PESs in different axes systems.

  10. Quantum chemical calculations and analysis of FTIR, FT-Raman and UV-Vis spectra of temozolomide molecule

    NASA Astrophysics Data System (ADS)

    Bhat, Sheeraz Ahmad; Ahmad, Shabbir

    2015-11-01

    A combined experimental and theoretical study of the structure, vibrational and electronic spectra of temozolomide molecule, which is largely used in the treatment of brain tumours, is presented. FTIR (4000-400 cm-1) and FT-Raman spectra (4000‒50 cm-1) have been recorded and analysed using anharmonic frequency calculations using VPT2, VSCF and CC-VSCF levels of theory within B3LYP/6-311++G(d,p) framework. Anharmonic methods give accurate frequencies of fundamental modes, overtones as well as Fermi resonances and account for coupling of different modes. The anharmonic frequencies calculated using VPT2 and CC-VSCF methods show better agreement with the experimental data. Harmonic frequencies including solvent effects are also computed using IEF-PCM model. The magnitudes of coupling between pair of modes have been calculated using coupling integral based on 2MR-QFF approximation. Intermolecular interactions are discussed for three possible dimers of temozolomide. UV-Vis spectrum, examined in ethanol solvent, is compared with the calculated spectrum at TD-DFT/6-311++G(d,p) level of theory. The electronic properties, such as excitation energy, frontier molecular orbital energies and the assignments of the absorption bands are also discussed.

  11. Peripheral neuropathy induced by combination chemotherapy of docetaxel and cisplatin.

    PubMed Central

    Hilkens, P. H.; Pronk, L. C.; Verweij, J.; Vecht, C. J.; van Putten, W. L.; van den Bent, M. J.

    1997-01-01

    Docetaxel, a new semisynthetic taxoid that has demonstrated promising activity as an antineoplastic agent, was administered in combination with cisplatin to 63 patients in a dose-escalating study. As both drugs were known to be potentially neurotoxic, peripheral neurotoxicity was prospectively assessed in detail. Neuropathy was evaluated by clinical sum-score for signs and symptoms and by measurement of the vibration perception threshold (VPT). The severity of neuropathy was graded according to the National Cancer Institute's 'Common Toxicity Criteria'. The docetaxel-cisplatin combination chemotherapy induced a predominantly sensory neuropathy in 29 (53%) out of 55 evaluable patients. At cumulative doses of both cisplatin and docetaxel above 200 mg m(-2), 26 (74%) out of 35 patients developed a neuropathy which was mild in 15, moderate in ten and severe in one patient. Significant correlations were present between both the cumulative dose of docetaxel and cisplatin and the post-treatment sum-score of neuropathy (P < 0.01) as well as the post-treatment VPT (P < 0.01). The neurotoxic effects of this combination were more severe than either cisplatin or docetaxel as single agent at similar doses. PMID:9020489

  12. Optical Properties of ZnO Soccer-Ball Structures Grown by Vapor Phase Transport

    NASA Astrophysics Data System (ADS)

    Nam, Giwoong; Lee, Sang-heon; Kim, Soaram; Kim, Min Su; Kim, Do Yeob; Gug Yim, Kwang; Lee, Dong-Yul; Kim, Jin Soo; Kim, Jong Su; Son, Jeong-Sik; Kim, Sung-O.; Jung, Jae Hak; Leem, Jae-Young

    2012-02-01

    ZnO soccer balls were grown on an Au-catalyzed Si(100) substrate by vapor phase transport (VPT) with a mixture of zinc oxide and graphite powders. Temperature-dependent PL was carried out to investigate the mechanism governing the quenching behavior of the PL spectra. From the PL spectra of the ZnO soccer balls at 10 K, several PL peaks were observed at 3.365, 3.318, 3.249, and 3.183 eV corresponding to excitons bound to neutral donors (DoX), a donor-acceptor pair (DAP), first-order longitudinal optical phonon replica of donor-acceptor pair (DAP-1LO), and DAP-2LO, respectively. The mixed system composed of the free exciton (FX) and DoX and the DAP radiative lifetimes were estimated with a theoretical relation between the lifetime and the spectral width. The exciton radiative lifetimes were observed to increase linearly with temperature.

  13. Phosphate Uptake and Allocation – A Closer Look at Arabidopsis thaliana L. and Oryza sativa L.

    PubMed Central

    Młodzińska, Ewa; Zboińska, Magdalena

    2016-01-01

    This year marks the 20th anniversary of the discovery and characterization of the two Arabidopsis PHT1 genes encoding the phosphate transporter in Arabidopsis thaliana. So far, multiple inorganic phosphate (Pi) transporters have been described, and the molecular basis of Pi acquisition by plants has been well-characterized. These genes are involved in Pi acquisition, allocation, and/or signal transduction. This review summarizes how Pi is taken up by the roots and further distributed within two plants: A. thaliana and Oryza sativa L. by plasma membrane phosphate transporters PHT1 and PHO1 as well as by intracellular transporters: PHO1, PHT2, PHT3, PHT4, PHT5 (VPT1), SPX-MFS and phosphate translocators family. We also describe the role of the PHT1 transporters in mycorrhizal roots of rice as an adaptive strategy to cope with limited phosphate availability in soil. PMID:27574525

  14. Structural investigation of thermo-responsive poly(2-isopropyl-2-oxazoline) hydrogel across the volume phase transition.

    PubMed

    Li, Tianjiao; Tang, Hui; Wu, Peiyi

    2015-03-14

    The deswelling and swelling behaviors of poly(2-isopropyl-2-oxazoline)-based hydrogel synthesized by a one-pot microwave-assisted solvent-free reaction were investigated. A distinct hydrophobic collapse of the hydrogel compared with the corresponding aqueous solution was observed by FT-IR spectroscopy combined with two-dimensional correlation spectroscopy (2DCOS) and perturbation-correlation moving-window (PCMW) analyses. The volume phase transition (VPT) temperature of 35 °C during heating and the transition temperature range of 41-30 °C during cooling were determined, indicating different dynamic transition mechanisms during heating and cooling. Water expulsion starting from the benzene ring-centered hydrophobic spots to the surroundings was revealed during deswelling. However, during swelling, although the rebuilding of cross-linking hydrogen bond bridges provided a channel-like microstructure to reswell the hydrogel gradually, a slow, unusual recovery of the amide hydrogen bonds to water molecules was observed. PMID:25611904

  15. Variational calculation of the limit cycle and its frequency in a two-neuron model with delay

    SciTech Connect

    Brandt, Sebastian F.; Wessel, Ralf; Pelster, Axel

    2006-09-15

    We consider a model system of two coupled Hopfield neurons, which is described by delay differential equations taking into account the finite signal propagation and processing times. When the delay exceeds a critical value, a limit cycle emerges via a supercritical Hopf bifurcation. First, we calculate its frequency and trajectory perturbatively by applying the Poincare-Lindstedt method. Then, the perturbation series are resummed by means of the Shohat expansion in good agreement with numerical values. However, with increasing delay, the accuracy of the results from the Shohat expansion worsens. We thus apply variational perturbation theory (VPT) to the perturbation expansions to obtain more accurate results, which moreover hold even in the limit of large delays.

  16. Differential dynamic microscopy to characterize Brownian motion and bacteria motility

    NASA Astrophysics Data System (ADS)

    Germain, David; Leocmach, Mathieu; Gibaud, Thomas

    2016-03-01

    We have developed a lab module for undergraduate students, which involves the process of quantifying the dynamics of a suspension of microscopic particles using Differential Dynamic Microscopy (DDM). DDM is a relatively new technique that constitutes an alternative method to more classical techniques such as dynamic light scattering (DLS) or video particle tracking (VPT). The technique consists of imaging a particle dispersion with a standard light microscope and a camera and analyzing the images using a digital Fourier transform to obtain the intermediate scattering function, an autocorrelation function that characterizes the dynamics of the dispersion. We first illustrate DDM in the textbook case of colloids under Brownian motion, where we measure the diffusion coefficient. Then we show that DDM is a pertinent tool to characterize biological systems such as motile bacteria.

  17. Optical sensor based on a single CdS nanobelt.

    PubMed

    Li, Lei; Yang, Shuming; Han, Feng; Wang, Liangjun; Zhang, Xiaotong; Jiang, Zhuangde; Pan, Anlian

    2014-04-23

    In this paper, an optical sensor based on a cadmium sulfide (CdS) nanobelt has been developed. The CdS nanobelt was synthesized by the vapor phase transportation (VPT) method. X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) results revealed that the nanobelt had a hexagonal wurtzite structure of CdS and presented good crystal quality. A single nanobelt Schottky contact optical sensor was fabricated by the electron beam lithography (EBL) technique, and the device current-voltage results showed back-to-back Schottky diode characteristics. The photosensitivity, dark current and the decay time of the sensor were 4 × 10⁴, 31 ms and 0.2 pA, respectively. The high photosensitivity and the short decay time were because of the exponential dependence of photocurrent on the number of the surface charges and the configuration of the back to back Schottky junctions.

  18. Color tunable electroluminescence and resistance switching from a ZnO-nanorod-TaOx-p-GaN heterojunction.

    PubMed

    Zhao, J L; Teo, K L; Zheng, K; Sun, X W

    2016-03-18

    Well-aligned ZnO nanorods have been prepared on p-GaN-sapphire using a vapor phase transport (VPT) technique. A thin sputtered layer of TaOx is employed as the intermediate layer and an n-ZnO-TaOx-p-GaN heterojunction device has been achieved. The current transport of the heterojunction exhibited a typical resistance switching behavior, which originated from the filament forming and breaking in the TaOx layer. Color controllable electroluminescence (EL) was observed from the biased heterojunction at room temperature. Bluish-white wide band emission is achieved from the forward biased device in both the high resistance and low resistance states, while red emission can only be observed for the reverse biased device in the low resistance state. The correlation between the EL and resistance switching has been analyzed in-depth based on the interface band diagram of the heterojunction. PMID:26878415

  19. Phosphate Uptake and Allocation - A Closer Look at Arabidopsis thaliana L. and Oryza sativa L.

    PubMed

    Młodzińska, Ewa; Zboińska, Magdalena

    2016-01-01

    This year marks the 20th anniversary of the discovery and characterization of the two Arabidopsis PHT1 genes encoding the phosphate transporter in Arabidopsis thaliana. So far, multiple inorganic phosphate (Pi) transporters have been described, and the molecular basis of Pi acquisition by plants has been well-characterized. These genes are involved in Pi acquisition, allocation, and/or signal transduction. This review summarizes how Pi is taken up by the roots and further distributed within two plants: A. thaliana and Oryza sativa L. by plasma membrane phosphate transporters PHT1 and PHO1 as well as by intracellular transporters: PHO1, PHT2, PHT3, PHT4, PHT5 (VPT1), SPX-MFS and phosphate translocators family. We also describe the role of the PHT1 transporters in mycorrhizal roots of rice as an adaptive strategy to cope with limited phosphate availability in soil. PMID:27574525

  20. Prediction of Fundamental Vibrational Frequencies and Infrared Intensities: a Benchmark Study

    NASA Astrophysics Data System (ADS)

    Vázquez, Juana; Harding, Michael E.; Stanton, John F.

    2011-06-01

    In this work we investigate the performance of second-order vibrational perturbation theory (VPT2) using force fields computed at the fc-CCSD(T) level in conjunction with different double-, triple-, and quadruple-ζ basis sets for the prediction of fundamental vibrational frequencies and infrared intensities. A benchmark study comprising more than thirty small and medium sized molecules illustrates the accuracy and limitations of the presented scheme. Atomic natural orbital (ANOY, Y=0,1,2) [J. Almlöf and P. R. Taylor, J. Chem. Phys. 86, 4070 (1987)] and correlation-consistent (cc-pVXZ, X=D,T,Q) [T. H. Dunning, Jr., J. Chem. Phys. 90, 1007 (1989)] basis sets.

  1. Color tunable electroluminescence and resistance switching from a ZnO-nanorod-TaO x -p-GaN heterojunction

    NASA Astrophysics Data System (ADS)

    Zhao, J. L.; Teo, K. L.; Zheng, K.; Sun, X. W.

    2016-03-01

    Well-aligned ZnO nanorods have been prepared on p-GaN-sapphire using a vapor phase transport (VPT) technique. A thin sputtered layer of TaO x is employed as the intermediate layer and an n-ZnO-TaO x -p-GaN heterojunction device has been achieved. The current transport of the heterojunction exhibited a typical resistance switching behavior, which originated from the filament forming and breaking in the TaO x layer. Color controllable electroluminescence (EL) was observed from the biased heterojunction at room temperature. Bluish-white wide band emission is achieved from the forward biased device in both the high resistance and low resistance states, while red emission can only be observed for the reverse biased device in the low resistance state. The correlation between the EL and resistance switching has been analyzed in-depth based on the interface band diagram of the heterojunction.

  2. UV light sensing properties of Sm doped vertically aligned ZnO nanorod arrays

    SciTech Connect

    Kumar, D. Ranjith; Ranjith, K. S.; Rajendrakumar, R. T.

    2015-06-24

    Samarium doped ZnO nanorods were grown on silicon substrate by using vapor phase transport method (VPT) with the growth temperature of 950°C. The synthesized nanorods were characterized by XRD, field emission scanning electron microscopy, Raman spectra, and photocurrent measurements. The XRD result revealed that Sm was successfully doped into lattice plane of hexagonal ZnO nanorods. The FESEM result confirms the pure ZnO has nanorod like morphology with an average diameter and length of 130nm and 10µm respectively. The above observation is supported by the Micro-Raman spectroscopy result. The photocurrent in the visible region has been significantly enhanced due to deposition of Sm on the surface of the ZnO nanorods. Sm acts as a visible sensitizer because of its lower band gap compared to ZnO.

  3. A new virion precipitation test for oncovirus envelope antigens which detects common antigenic determinants in mammalian type-C viruses and Mason-Pfizer monkey virus.

    PubMed

    Altstein, A D; Zakharova, L G; Zhdanov, V M

    1979-03-15

    A method for the study of oncovirus envelope antigens was developed, bases on the precipitation of intact virions by a double antibody technique. The amount of precipitated virus was then measured as reverse transcriptase activity. The method was designated the virion precipitation test (VPT). It has been used for titration of antibodies to envelope antigens of oncoviruses. The study of envelop antigens of 11 different oncoviruses permitted their differentiation into the following groups: (1) murine type-C viruses: (2) feline type-C viruses; (3) simian type-C viruses; (4) the RD-114/BEV group; (5) Mason-Pfizer monkey virus (M-PMV); (6) bovine leukemia virus; (7) avian type-C viruses; (8) mouse mammary tumor virus. No common antigenic determinants were detected in the last three groups. Mammalian type-C viruses (RD-114, NIH-MuLV, G-MuLV) had common antigenic determinants in the envelope, as demonstrated with an anti-RD-114 serum. Mammalian type-C viruses also shared antigenic determinants with M-PMV. The relationship of type-C viruses to M-PMV decreased in the following order: RD-114--NIH-MuLV--G-MuLV. It was also shown that the endogenous xenotropic feline RD-114 virus was more closely related to xenotropic NIH-MuLV than to ecotropic G-MuLV. The nature of the common antigenic determinants, as demonstrated by VPT on the surface of mammalian type-C viruses and M-PMV, and their significance for the concept of oncovirus evolution are discussed.

  4. Complete Assignment of the Infrared Spectrum of the Gas-Phase Protonated Ammonia Dimer.

    PubMed

    Wang, Huan; Agmon, Noam

    2016-05-19

    The infrared (IR) spectrum of the ammoniated ammonium dimer is more complex than those of the larger protonated ammonia clusters due to close-lying fundamental and combination bands and possible Fermi resonances (FR). To date, the only theoretical analysis involved partial dimensionality quantum nuclear dynamic simulations, assuming a symmetric structure (D3d) with the proton midway between the two nitrogen atoms. Here we report an extensive study of the less symmetric (C3v) dimer, utilizing both second order vibrational perturbation theory (VPT2) and ab initio molecular dynamics (AIMD), from which we calculated the Fourier transform (FT) of the dipole-moment autocorrelation function (DACF). The resultant IR spectrum was assigned using FTed velocity autocorrelation functions (VACFs) of several interatomic distances and angles. At 50 K, we have been able to assign all 21 AIMD fundamentals, in reasonable agreement with MP2-based VPT2, about 30 AIMD combination bands, and a difference band. The combinations involve a wag or the NN stretch as one of the components, and appear to follow symmetry selection rules. On this basis, we suggest possible assignments of the experimental spectrum. The VACF-analysis revealed two possible FR bands, one of which is the strongest peak in the computed spectrum. Raising the temperature to 180 K eliminated the "proton transfer mode" (PTM) fundamental, and reduced the number of observed combination bands and FRs. With increasing temperature, fundamentals red-shift, and the doubly degenerate wags exhibit larger anharmonic splittings in their VACF bending spectra. We have repeated the analysis for the H3ND(+)NH3 isotopologue, finding that it has a simplified spectrum, with all the strong peaks being fundamentals. Experimental study of this isotopologue may thus provide a good starting point for disentangling the N2H7(+) spectrum.

  5. Long-Term Neurotoxicity of Chemotherapy in Adolescents and Young Adults Treated for Bone and Soft Tissue Sarcomas

    PubMed Central

    Connolly, Sean; Latoufis, Christos; Eagle, Karen; Ash, Catherine M.; Fowler, Clare; Souhami, Robert L.

    1998-01-01

    Purpose. To study the long-term neurotoxicity of chemotherapy in adolescents and young adults treated for bone and soft tissue sarcomas. Patients and Methods. Thirty-six adolescents and young adults (median age 17 years) were examined following chemotherapy for bone and soft tissue sarcomas. Twenty-nine (29/36) had received cisplatin (median 400 mg/m2), 15/36 ifosfamide (median 20 g/m2), and 12/36 vincristine (median 16 mg). Neurotoxicity was assessed at a median of 8 months (range, 1–54 months) after completion of chemotherapy by clinical examination, nerve conduction studies, audiograms and autonomic function tests. The same nerve conduction studies were carried out in 20 normal volunteers to define normal ranges in this age group. Results. Sixteen patients (44%) had a significant reduction in deep tendon reflexes, and this clinical parameter correlated well with abnormalities detected in nerve conduction studies. Vibration perception threshold (VPT) was raised in 20/36 patients (55%) and this was the most sensitive single test in the assessment of neuropathy. There was a significant correlation between VPT and cumulative cisplatin dose received in mg/m-2 (r=0.607, p<0.01). Ten of 29 patients (35%) had abnormal nerve conduction studies with a pattern characteristic of sensory axonal neuropathy. No patient complained of auditory symptoms, but minor high tone hearing loss was detected by audiograms in 5/28 patients who had received cisplatin. No patients had symptoms of autonomic neuropathy, but autonomic function tests showed minor abnormalities in 4/22 patients tested, and all had received cisplatin. Conclusions. This study demonstrates significant, although asymptomatic, long-term neurotoxicity of cisplatin in adolescents and young adults receiving chemotherapy for bone and soft tissue sarcomas. Follow-up studies are planned to assess whether these neurological deficits improve with time. PMID:18521240

  6. Complete Assignment of the Infrared Spectrum of the Gas-Phase Protonated Ammonia Dimer.

    PubMed

    Wang, Huan; Agmon, Noam

    2016-05-19

    The infrared (IR) spectrum of the ammoniated ammonium dimer is more complex than those of the larger protonated ammonia clusters due to close-lying fundamental and combination bands and possible Fermi resonances (FR). To date, the only theoretical analysis involved partial dimensionality quantum nuclear dynamic simulations, assuming a symmetric structure (D3d) with the proton midway between the two nitrogen atoms. Here we report an extensive study of the less symmetric (C3v) dimer, utilizing both second order vibrational perturbation theory (VPT2) and ab initio molecular dynamics (AIMD), from which we calculated the Fourier transform (FT) of the dipole-moment autocorrelation function (DACF). The resultant IR spectrum was assigned using FTed velocity autocorrelation functions (VACFs) of several interatomic distances and angles. At 50 K, we have been able to assign all 21 AIMD fundamentals, in reasonable agreement with MP2-based VPT2, about 30 AIMD combination bands, and a difference band. The combinations involve a wag or the NN stretch as one of the components, and appear to follow symmetry selection rules. On this basis, we suggest possible assignments of the experimental spectrum. The VACF-analysis revealed two possible FR bands, one of which is the strongest peak in the computed spectrum. Raising the temperature to 180 K eliminated the "proton transfer mode" (PTM) fundamental, and reduced the number of observed combination bands and FRs. With increasing temperature, fundamentals red-shift, and the doubly degenerate wags exhibit larger anharmonic splittings in their VACF bending spectra. We have repeated the analysis for the H3ND(+)NH3 isotopologue, finding that it has a simplified spectrum, with all the strong peaks being fundamentals. Experimental study of this isotopologue may thus provide a good starting point for disentangling the N2H7(+) spectrum. PMID:27124704

  7. Realizations of the ITS-90 below 24.5561 K at NMIJ/AIST

    NASA Astrophysics Data System (ADS)

    Tamura, O.; Nakano, T.; Shimazaki, T.; Takasu, S.

    2013-09-01

    The International Temperature Scale of 1990 (ITS-90) down to its defined minimum temperature of 0.65 K has been realized at the National Metrology Institute of Japan (NMIJ), using a 3He vapor pressure thermometer (VPT) from 0.65 K to 3.2 K, a 4He VPT from 2.2 K to 4.2 K, an interpolating constant-volume gas thermometer (ICVGT) from 3 K to 24.5561 K and standard platinum resistance thermometers (SPRTs) above 13.8803 K. The scales realized by these different thermometers in the overlapped temperature ranges differ among each other. These differences, also known as the non-uniqueness of the ITS-90, are estimated and reported in this paper. The difference between the scales of the SPRTs and ICVGT has a maximum of about 0.6 mK at temperatures close to 15 K, though it is about half of the propagation of the calibration uncertainties of the SPRT at the fixed points. The difference between the vapor pressure scales of 4He and 3He shows temperature dependence, which is consistent with that reported previously and has a maximum of about 0.2 mK at temperatures close to 3.1 K. The differences between the ICVGT scales with different lowest calibration temperatures are also estimated. The difference between the ICVGT scales with or without corrections for the aerostatic pressure head, the dead-space volume effect and the thermomolecular pressure difference has a maximum of about 0.17 mK.

  8. Thresholds of skin sensitivity are partially influenced by mechanical properties of the skin on the foot sole

    PubMed Central

    Strzalkowski, Nicholas D J; Triano, John J; Lam, Chris K; Templeton, Cale A; Bent, Leah R

    2015-01-01

    Across the foot sole, there are vibration and monofilament sensory differences despite an alleged even distribution of cutaneous afferents. Mechanical property differences across foot sole sites have been proposed to account for these differences. Vibration (VPT; 3 Hz, 40 Hz, 250 Hz), and monofilament (MF) perception threshold measurements were compared with skin hardness, epidermal thickness, and stretch response across five foot sole locations in young healthy adults (n = 22). Perceptual thresholds were expected to correlate with all mechanical property measurements to help address sensitivity differences between sites. Following this hypothesis, the MedArch was consistently found to be the thinnest and softest site and demonstrated the greatest sensitivity. Conversely, the Heel was found to be the thickest and hardest site, and was relatively insensitive across perceptual tests. Site differences were not observed for epidermal stretch response measures. Despite an apparent trend of elevated sensory threshold at harder and thicker sites, significant correlations between sensitivity measures and skin mechanical properties were not observed. Skin hardness and epidermal thickness appeared to have a negligible influence on VPT and minor influence on MF within this young healthy population. When normalized (% greater or smaller than subject mean) to the subject mean for each variable, significant positive correlations were observed between MF and skin hardness (R2 = 0.422, P < 0.0001) and epidermal thickness (R2 = 0.433, P < 0.0001) providing evidence that skin mechanics can influence MF threshold. In young healthy adults, differences in sensitivity are present across the foot sole, but cannot solely be accounted for by differences in the mechanical properties of the skin. PMID:26059035

  9. Assessment of chemotherapy-induced peripheral neuropathy using the LDIFLARE technique: a novel technique to detect neural small fiber dysfunction

    PubMed Central

    Sharma, Sanjeev; Venkitaraman, Ramachandran; Vas, Prashanth R J; Rayman, Gerry

    2015-01-01

    Introduction The diagnosis and quantification of chemotherapy-induced peripheral neuropathy (CIPN) remains a challenge. Conventional methods including quantitative sensory testing (QST), nerve conduction tests, and biopsy are unable to detect subclinical changes, and do not consistently correlate with severity of patients' symptoms and functional impairment. This study aims to determine the utility of the LDI (laser Doppler imager) FLARE technique in the diagnosis of CIPN and whether it correlates with symptom severity. Materials and Methods We assessed 24 patients with established CIPN [12 due to platinum analogs (PA) and 12 to Taxanes (TX)] and 24 matched healthy controls (HC). All underwent neurophysiological examination including vibration perception threshold (VPT), sural nerve amplitude (SNAP) and conduction velocity (SNCV), LDIFLARE, and fasting biochemistry. The QLQ-CIPN20 questionnaire was used to assess symptom severity. Results HC, combined chemotherapy (CG), PA, and TX groups were matched for age, sex, BMI, and blood pressure. The LDIFLARE was significantly reduced in CG compared to HC (P =< 0.0001), whereas SNAP (P = 0.058) and SNCV (P = 0.054) were not. The LDIFLARE correlated with the QLQ-CIPN20 symptom scores in all three categories namely, CG (P =< 0.0001), PA (P = 0.001) and TX (P = 0.027) whilst, VPT, SNAP, and SNCV did not. Conclusion Our findings suggest that the LDIFLARE technique is more helpful in confirming the diagnosis of CIPN in patients with distal sensory symptoms than current commonly used methods. Moreover, this novel test fulfils the unmet need for a diagnostic test that relates to the severity of symptoms. This may be useful in quantifying early changes in small fibre function indicating early CIPN. PMID:26221574

  10. Realizations of the ITS-90 below 24.5561 K at NMIJ/AIST

    SciTech Connect

    Tamura, O.; Nakano, T.; Shimazaki, T.; Takasu, S.

    2013-09-11

    The International Temperature Scale of 1990 (ITS-90) down to its defined minimum temperature of 0.65 K has been realized at the National Metrology Institute of Japan (NMIJ), using a {sup 3}He vapor pressure thermometer (VPT) from 0.65 K to 3.2 K, a {sup 4}He VPT from 2.2 K to 4.2 K, an interpolating constant-volume gas thermometer (ICVGT) from 3 K to 24.5561 K and standard platinum resistance thermometers (SPRTs) above 13.8803 K. The scales realized by these different thermometers in the overlapped temperature ranges differ among each other. These differences, also known as the non-uniqueness of the ITS-90, are estimated and reported in this paper. The difference between the scales of the SPRTs and ICVGT has a maximum of about 0.6 mK at temperatures close to 15 K, though it is about half of the propagation of the calibration uncertainties of the SPRT at the fixed points. The difference between the vapor pressure scales of {sup 4}He and {sup 3}He shows temperature dependence, which is consistent with that reported previously and has a maximum of about 0.2 mK at temperatures close to 3.1 K. The differences between the ICVGT scales with different lowest calibration temperatures are also estimated. The difference between the ICVGT scales with or without corrections for the aerostatic pressure head, the dead-space volume effect and the thermomolecular pressure difference has a maximum of about 0.17 mK.

  11. Effectiveness and Comparison of Various Audio Distraction Aids in Management of Anxious Dental Paediatric Patients

    PubMed Central

    Johri, Nikita; Khan, Suleman Abbas; Singh, Rahul Kumar; Chadha, Dheera; Navit, Pragati; Sharma, Anshul; Bahuguna, Rachana

    2015-01-01

    Background Dental anxiety is a widespread phenomenon and a concern for paediatric dentistry. The inability of children to deal with threatening dental stimuli often manifests as behaviour management problems. Nowadays, the use of non-aversive behaviour management techniques is more advocated, which are more acceptable to parents, patients and practitioners. Therefore, this present study was conducted to find out which audio aid was the most effective in the managing anxious children. Aims and Objectives The aim of the present study was to compare the efficacy of audio-distraction aids in reducing the anxiety of paediatric patients while undergoing various stressful and invasive dental procedures. The objectives were to ascertain whether audio distraction is an effective means of anxiety management and which type of audio aid is the most effective. Materials and Methods A total number of 150 children, aged between 6 to 12 years, randomly selected amongst the patients who came for their first dental check-up, were placed in five groups of 30 each. These groups were the control group, the instrumental music group, the musical nursery rhymes group, the movie songs group and the audio stories group. The control group was treated under normal set-up & audio group listened to various audio presentations during treatment. Each child had four visits. In each visit, after the procedures was completed, the anxiety levels of the children were measured by the Venham’s Picture Test (VPT), Venham’s Clinical Rating Scale (VCRS) and pulse rate measurement with the help of pulse oximeter. Results A significant difference was seen between all the groups for the mean pulse rate, with an increase in subsequent visit. However, no significant difference was seen in the VPT & VCRS scores between all the groups. Audio aids in general reduced anxiety in comparison to the control group, and the most significant reduction in anxiety level was observed in the audio stories group

  12. Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass.

    PubMed

    Thandavan, Tamil Many K; Gani, Siti Meriam Abdul; San Wong, Chiow; Md Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs.

  13. Characterizing a nonclassical carbene with coupled cluster methods: cyclobutylidene.

    PubMed

    Wang, Xiao; Agarwal, Jay; Schaefer Iii, Henry F

    2016-09-21

    Carbenes represent a special class of reactive compounds that possess a lone pair of electrons on a carbon atom. Among the myriad examples of carbenes in the literature, cyclobutylidene stands out as a unique nonclassical compound that includes transannular interaction between opposing C1 and C3 carbon atoms within a four-membered ring. On its lowest potential energy surface (X[combining tilde](1)A'), cyclobutylidene quickly rearranges, following three reaction paths: (i) 1,2-H migration; (ii) 1,2-C migration; and, (iii) 1,3-H migration. Herein, this reactivity is examined with high-level coupled-cluster methods [up to CCSDT(Q)]. At this level of theory, combined with extrapolation techniques to obtain energies at the complete basis set (CBS) limit, the long-standing disparity between theoretical and experimental results is resolved. Specifically, cyclobutylidene is predicted to prefer 1,2-C migration rather than 1,2-H migration. Rate constants for the three reaction paths are obtained from canonical variational transition state theory (CVT) and yield reasonable agreement with existing experimental results. Further characterization of cyclobutylidene is also reported: the singlet-triplet gap (ΔES-T) is found to be -9.3 kcal mol(-1) at the CCSDT(Q)/CBS level of theory, and anharmonic vibrational frequencies are determined with second-order vibrational perturbation theory (VPT2). PMID:27539444

  14. Infrared Laser Spectroscopy of the n-PROPYL and i-PROPYL Radicals in Helium Droplets: Significant Bend-Stretch Coupling Revealed in the CH Stretch Region

    NASA Astrophysics Data System (ADS)

    Moradi, Christopher P.; Douberly, Gary E.; Tabor, Daniel P.; Sibert, Edwin

    2016-06-01

    The n-propyl and i-propyl radicals were generated in the gas phase via pyrolysis of n-butyl nitrite (CH3(CH2)3ONO) and i-butyl nitrite (CH3CH(CH3)CH2ONO) precursors, respectively. Nascent radicals were promptly solvated by a beam of He nanodroplets, and the infrared spectra of the radicals were recorded in the C-H stretching region. In addition to three vibrations of n-propyl previously measured in an Ar matrix, we observe many unreported bands between 2800 and 3150 wn, which we attribute to propyl radicals. The C-H stretching modes observed above 2960 wn for both radicals are in excellent agreement with anharmonic frequencies computed using VPT2. Between 2800 and 2960 wn, however, the spectra of n-propyl and i-propyl radicals become quite congested and difficult to assign due to the presence of multiple anharmonic resonances. Computations employing a local mode Hamiltonian reveal the origin of the spectral congestion to be strong coupling between the high frequency C-H stretching modes and the lower frequency bending/scissoring motions. The only significant local coupling is between stretches and bends on the same CH2/CH3 group.

  15. Experimental and theoretical studies of the vibrational spectra of CHD2Br

    NASA Astrophysics Data System (ADS)

    Baldacci, A.; Stoppa, P.; Baldan, A.; Visinoni, R.; Gambi, A.

    2012-09-01

    The dideuterated form of methyl bromide, CHD2Br, has been synthesized and the gas-phase infrared spectra investigated in the range 400-10,000 cm-1 using a medium-resolution FTIR spectrometer. The nine fundamental bands have been characterized in detail. Six of them, i.e. ν 1, ν 4, ν 5, ν 7, ν 8 and ν 9, have been rotationally analysed through the assignment of the partially resolved structure of the PQK and RQK cluster of lines and the spectroscopic parameters have been derived in the symmetric top limit approximation. Among the fundamental levels, anharmonic resonance occurs between ν 7/ν 4 + ν 8 and ν 8/ν 6 + ν 9. An isotopic 79/81Br shift was found for ν 6 and in the more complex region of the ν 8 fundamental. High-quality ab initio calculations - carried out at coupled cluster level [CCSD(T)] employing the correlation-consistent basis set of Dunning (cc-pVTZ) - were performed to determine quadratic, cubic and quartic (semidiagonal) force constants. Using these constants and applying second-order vibrational perturbation theory (VPT2), with allowance for resonances (when necessary), permitted us to identify and assign, in addition to the fundamentals, about 70 overtones and combination bands up to three quanta.

  16. Visual learning by imitation with motor representations.

    PubMed

    Lopes, Manuel; Santos-Victor, José

    2005-06-01

    We propose a general architecture for action (mimicking) and program (gesture) level visual imitation. Action-level imitation involves two modules. The viewpoint Transformation (VPT) performs a "rotation" to align the demonstrator's body to that of the learner. The Visuo-Motor Map (VMM) maps this visual information to motor data. For program-level (gesture) imitation, there is an additional module that allows the system to recognize and generate its own interpretation of observed gestures to produce similar gestures/goals at a later stage. Besides the holistic approach to the problem, our approach differs from traditional work in i) the use of motor information for gesture recognition; ii) usage of context (e.g., object affordances) to focus the attention of the recognition system and reduce ambiguities, and iii) use iconic image representations for the hand, as opposed to fitting kinematic models to the video sequence. This approach is motivated by the finding of visuomotor neurons in the F5 area of the macaque brain that suggest that gesture recognition/imitation is performed in motor terms (mirror) and rely on the use of object affordances (canonical) to handle ambiguous actions. Our results show that this approach can outperform more conventional (e.g., pure visual) methods.

  17. Synthesis and characterization of multi-responsive poly (NIPAm-co-AAc) microgels

    NASA Astrophysics Data System (ADS)

    Haider, Irfan; Siddiq, Mohammad; Mujtaba Shah, Syed; Rehman, Saif ur

    2014-06-01

    Two samples of multi-responsive copolymer microgels, poly(N-isopropylacrylamide-co-acrylic acid) [P(NIPAm-co-AAc)], were synthesized by emulsion polymerization using different amounts of emulsifier. The unreacted monomers and surfactant were removed from the microgels by dialysis. Dynamic Laser Light Scattering (DLS) was used to determine the diffusion coefficient and hydrodynamic radius (Rh) of the microgels at different pH values and temperatures. At pH 7 the microgel showed rapid response to temperature and underwent volume phase transition (VPT) as the temperature was raised. At lower temperature the microgels were in the hydrated or swollen state but beyond 38oC, the size was abruptly decreased. Under different conditions of pH and NaCl concentrations, variations in VPTT values were noticed. By increasing pH the VPTT was increased but the addition of salt had an inverse effect. The weight average molar mass (Mw) and radius of gyration (Rg) were measured by Static Laser Light Scattering (SLS). FTIR spectroscopy was used to confirm the chemical structures of microgels

  18. Structure, Anharmonic Vibrational Frequencies, and Intensities of NNHNN(+).

    PubMed

    Yu, Qi; Bowman, Joel M; Fortenberry, Ryan C; Mancini, John S; Lee, Timothy J; Crawford, T Daniel; Klemperer, William; Francisco, Joseph S

    2015-11-25

    A semiglobal potential energy surface (PES) and quartic force field (QFF) based on fitting high-level electronic structure energies are presented to describe the structures and spectroscopic properties of NNHNN(+). The equilibrium structure of NNHNN(+) is linear with the proton equidistant between the two nitrogen groups and thus of D(∞h) symmetry. Vibrational second-order perturbation theory (VPT2) calculations based on the QFF fails to describe the proton "rattle" motion, i.e., the antisymmetric proton stretch, due to the very flat nature of PES around the global minimum but performs properly for other modes with sharper potential wells. Vibrational self-consistent field/virtual state configuration interaction (VSCF/VCI) calculations using a version of MULTIMODE without angular momentum terms successfully describe this motion and predict the fundamental to be at 759 cm(-1). This is in good agreement with the value of 746 cm(-1) from a fixed-node diffusion Monte Carlo calculation and the experimental Ar-tagged result of 743 cm(-1). Other VSCF/VCI energies are in good agreement with other experimentally reported ones. Both double-harmonic intensity and rigorous MULTIMODE intensity calculations show the proton-transfer fundamental has strong intensity. PMID:26529262

  19. Structural and biological evaluation of some metal complexes of vanillin-4N-(2-pyridyl) thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Yousef, T. A.; Abu El-Reash, G. M.; Al-Jahdali, M.; El-Rakhawy, El-Bastawesy R.

    2013-12-01

    The synthesis and characterization of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and U(VI)O2 complexes of vanillin-4N-(2-pyridyl) thiosemicarbazone (H2PVT) are reported. Theoretical calculations have been performed to obtain IR spectra of ligand and its complexes using AM1, Zindo/1, MM+ and PM3, methods. The Schiff base and its metal complexes have been screened for antibacterial Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus saprophyticus. H2VPT shows no apparent digestion effect on the egg albumin while Mn(II), Hg(II) and Cu(II) complexes exhibited a considerable digestion effect following the order Cu(II) > Mn(II) > Hg(II). Moreover, Ni(II) and Co(II) complexes revealed strong digestion effect. Fe(II), Mn(II), Cu(II), Zn(II) and Ni(II) acted as metal co- SOD enzyme factors, which are located in different compartments of the cell.

  20. Abnormal cold perception in the lower limbs: a sensitive indicator for detection of polyneuropathy in patients with type 1 diabetes mellitus.

    PubMed

    Hyllienmark, L; Jonsson, B; Ekberg, K; Lindström, P

    2009-09-01

    Diabetic peripheral neuropathy differs in type 1 and type 2 diabetes. The aim of this study was to evaluate how signs and symptoms of neuropathy correlated with defects in motor and sensory nerve conduction velocity (MCV and SCV) and sensory perception thresholds in patients with type 1 diabetes. MCV and SCV in peroneal and sural nerves and vibratory, warm and cold perception thresholds (VPT, WPT, CPT) were evaluated in the lower limbs of 127 patients (42+/-7.9 years old, duration of diabetes, 16+/-11 years and HbA1c, 7.7+/-1.4%). The results were compared with clinical findings (neuropathy impairment assessment, NIA) and sensory symptoms (neurological symptom assessment, NSA). Sensory symptoms were present in 24% of patients, 91% had at least one abnormal finding in the neurological examination and 84% had abnormal nerve conduction. The greatest deviation from normal was observed for CPT on the dorsum of the foot and peroneal MCV. NIA and NSA correlated with all electrophysiological measurements in the foot and big toe. It is concluded that clinical findings correlate well with electrophysiological abnormalities in patients with type 1 diabetic neuropathy. An elevated CPT for the foot was the most pronounced sensory defect.

  1. Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

    PubMed Central

    Thandavan, Tamil Many K.; Gani, Siti Meriam Abdul; San Wong, Chiow; Md. Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs. PMID:25756598

  2. Generalized Vibrational Perturbation Theory for Rotovibrational Energies of Linear, Symmetric and Asymmetric Tops: Theory, Approximations, and Automated Approaches to Deal with Medium-to-Large Molecular Systems

    PubMed Central

    Piccardo, Matteo; Bloino, Julien; Barone, Vincenzo

    2015-01-01

    Models going beyond the rigid-rotor and the harmonic oscillator levels are mandatory for providing accurate theoretical predictions for several spectroscopic properties. Different strategies have been devised for this purpose. Among them, the treatment by perturbation theory of the molecular Hamiltonian after its expansion in power series of products of vibrational and rotational operators, also referred to as vibrational perturbation theory (VPT), is particularly appealing for its computational efficiency to treat medium-to-large systems. Moreover, generalized (GVPT) strategies combining the use of perturbative and variational formalisms can be adopted to further improve the accuracy of the results, with the first approach used for weakly coupled terms, and the second one to handle tightly coupled ones. In this context, the GVPT formulation for asymmetric, symmetric, and linear tops is revisited and fully generalized to both minima and first-order saddle points of the molecular potential energy surface. The computational strategies and approximations that can be adopted in dealing with GVPT computations are pointed out, with a particular attention devoted to the treatment of symmetry and degeneracies. A number of tests and applications are discussed, to show the possibilities of the developments, as regards both the variety of treatable systems and eligible methods. © 2015 Wiley Periodicals, Inc. PMID:26345131

  3. The effect of hydrogen bonding on torsional dynamics: A combined far-infrared jet and matrix isolation study of methanol dimer

    SciTech Connect

    Kollipost, F.; Heger, M.; Suhm, M. A.; Andersen, J.; Mahler, D. W.; Wugt Larsen, R.; Heimdal, J.

    2014-11-07

    The effect of strong intermolecular hydrogen bonding on torsional degrees of freedom is investigated by far-infrared absorption spectroscopy for different methanol dimer isotopologues isolated in supersonic jet expansions or embedded in inert neon matrices at low temperatures. For the vacuum-isolated and Ne-embedded methanol dimer, the hydrogen bond OH librational mode of the donor subunit is finally observed at ∼560 cm{sup −1}, blue-shifted by more than 300 cm{sup −1} relative to the OH torsional fundamental of the free methanol monomer. The OH torsional mode of the acceptor embedded in neon is observed at ∼286 cm{sup −1}. The experimental findings are held against harmonic predictions from local coupled-cluster methods with single and double excitations and a perturbative treatment of triple excitations [LCCSD(T)] and anharmonic. VPT2 corrections at canonical MP2 and density functional theory (DFT) levels in order to quantify the contribution of vibrational anharmonicity for this important class of intermolecular hydrogen bond vibrational motion.

  4. The effect of hydrogen bonding on torsional dynamics: a combined far-infrared jet and matrix isolation study of methanol dimer.

    PubMed

    Kollipost, F; Andersen, J; Mahler, D W; Heimdal, J; Heger, M; Suhm, M A; Wugt Larsen, R

    2014-11-01

    The effect of strong intermolecular hydrogen bonding on torsional degrees of freedom is investigated by far-infrared absorption spectroscopy for different methanol dimer isotopologues isolated in supersonic jet expansions or embedded in inert neon matrices at low temperatures. For the vacuum-isolated and Ne-embedded methanol dimer, the hydrogen bond OH librational mode of the donor subunit is finally observed at ~560 cm(-1), blue-shifted by more than 300 cm(-1) relative to the OH torsional fundamental of the free methanol monomer. The OH torsional mode of the acceptor embedded in neon is observed at ~286 cm(-1). The experimental findings are held against harmonic predictions from local coupled-cluster methods with single and double excitations and a perturbative treatment of triple excitations [LCCSD(T)] and anharmonic. VPT2 corrections at canonical MP2 and density functional theory (DFT) levels in order to quantify the contribution of vibrational anharmonicity for this important class of intermolecular hydrogen bond vibrational motion. PMID:25381521

  5. Identification of plant vacuolar transporters mediating phosphate storage

    PubMed Central

    Liu, Tzu-Yin; Huang, Teng-Kuei; Yang, Shu-Yi; Hong, Yu-Ting; Huang, Sheng-Min; Wang, Fu-Nien; Chiang, Su-Fen; Tsai, Shang-Yueh; Lu, Wen-Chien; Chiou, Tzyy-Jen

    2016-01-01

    Plant vacuoles serve as the primary intracellular compartments for inorganic phosphate (Pi) storage. Passage of Pi across vacuolar membranes plays a critical role in buffering the cytoplasmic Pi level against fluctuations of external Pi and metabolic activities. Here we demonstrate that the SPX-MFS proteins, designated as PHOSPHATE TRANSPORTER 5 family (PHT5), also named Vacuolar Phosphate Transporter (VPT), function as vacuolar Pi transporters. Based on 31P-magnetic resonance spectroscopy analysis, Arabidopsis pht5;1 loss-of-function mutants accumulate less Pi and exhibit a lower vacuolar-to-cytoplasmic Pi ratio than controls. Conversely, overexpression of PHT5 leads to massive Pi sequestration into vacuoles and altered regulation of Pi starvation-responsive genes. Furthermore, we show that heterologous expression of the rice homologue OsSPX-MFS1 mediates Pi influx to yeast vacuoles. Our findings show that a group of Pi transporters in vacuolar membranes regulate cytoplasmic Pi homeostasis and are required for fitness and plant growth. PMID:27029856

  6. The cogeneration steam turbine of the Tp-35/40-8.8 type

    NASA Astrophysics Data System (ADS)

    Valamin, A. Ye.; Kultyshev, A. Yu.; Goldberg, A. A.; Sakhnin, Yu. A.; Shekhter, M. V.; Paneque Aguilera, H. C.; Stepanov, M. Yu.; Shibaev, T. L.

    2012-12-01

    The main performance characteristics of the turbine, descriptions of the electrohydraulic control and protection system (EHCPS), the heat flow diagram, arrangement decisions, and motivation for selecting them, are given. The steam turbine presented by the Ural Turbine Works (UTW) is intended for replacing the VPT-25 turbine the service life of which has already expired at the Novokuybyshevsk CHP plant. The mixed-pressure turbine will operate in combination of the double-circuit heat recovery boiler (HRB) in a parallel scheme. High-pressure (HP) steam will be supplied from the main steam header to which high-pressure steam from the power boilers and the HRB will be fed, while low-pressure (LP) steam will be supplied directly from the HRB. For the turbine, nozzle steam distribution and the two-row control stage are adopted. The turbine has a process steam extraction line with its stop and control valve and heating steam extraction line leading to the main steam collector.

  7. Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass.

    PubMed

    Thandavan, Tamil Many K; Gani, Siti Meriam Abdul; San Wong, Chiow; Md Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs. PMID:25756598

  8. Corneal Confocal Microscopy Detects Neuropathy in Patients with Type 1 Diabetes without Retinopathy or Microalbuminuria

    PubMed Central

    Chan, Agnes W. S.; Alam, Uazman; Fadavi, Hassan; Marshall, Andrew; Asghar, Omar; Efron, Nathan; Tavakoli, Mitra; Malik, Rayaz A.

    2015-01-01

    Objective Corneal innervation is increasingly used as a surrogate marker of human diabetic peripheral neuropathy (DPN) however its temporal relationship with the other microvascular complications of diabetes is not fully established. In this cross-sectional, observational study we aimed to assess whether neuropathy occurred in patients with type 1 diabetes, without retinopathy or microalbuminuria. Materials and Methods All participants underwent detailed assessment of peripheral neuropathy [neuropathy disability score (NDS), vibration perception threshold (VPT), peroneal motor nerve conduction velocity (PMNCV), sural sensory nerve conduction velocity (SSNCV) and in vivo corneal confocal microscopy (IVCCM)], retinopathy (digital fundus photography) and albuminuria status [albumin: creatinine ratio (ACR)]. Results 53 patients with Type 1 diabetes with (n=37) and without retinopathy (n=16) were compared to control subjects (n=27). SSNCV, corneal nerve fibre (CNFD) and branch (CNBD) density and length (CNFL) were reduced significantly (p<0.001) in diabetic patients without retinopathy compared to control subjects. Furthermore, CNFD, CNBD and CNFL were also significantly (p<0.001) reduced in diabetic patients without microalbuminuria (n=39), compared to control subjects. Greater neuropathic severity was associated with established retinopathy and microalbuminuria. Conclusions IVCCM detects early small fibre damage in the absence of retinopathy or microalbuminuria in patients with Type 1 diabetes. PMID:25853247

  9. The Inferior Whorl For Detecting Diabetic Peripheral Neuropathy Using Corneal Confocal Microscopy

    PubMed Central

    Petropoulos, Ioannis N.; Ferdousi, Maryam; Marshall, Andrew; Alam, Uazman; Ponirakis, Georgios; Azmi, Shazli; Fadavi, Hassan; Efron, Nathan; Tavakoli, Mitra; Malik, Rayaz A.

    2015-01-01

    Purpose. In vivo corneal confocal microscopy (CCM) is increasingly used as a surrogate endpoint in studies of diabetic polyneuropathy (DPN). However, it is not clear whether imaging the central cornea provides optimal diagnostic utility for DPN. Therefore, we compared nerve morphology in the central cornea and the inferior whorl, a more distal and densely innervated area located inferior and nasal to the central cornea. Methods. A total of 53 subjects with type 1/type 2 diabetes and 15 age-matched control subjects underwent detailed assessment of neuropathic symptoms (NPS), deficits (neuropathy disability score [NDS]), quantitative sensory testing (vibration perception threshold [VPT], cold and warm threshold [CT/WT], and cold- and heat-induced pain [CIP/HIP]), and electrophysiology (sural and peroneal nerve conduction velocity [SSNCV/PMNCV], and sural and peroneal nerve amplitude [SSNA/PMNA]) to diagnose patients with (DPN+) and without (DPN−) neuropathy. Corneal nerve fiber density (CNFD) and length (CNFL) in the central cornea, and inferior whorl length (IWL) were quantified. Results. Comparing control subjects to DPN− and DPN+ patients, there was a significant increase in NDS (0 vs. 2.6 ± 2.3 vs. 3.3 ± 2.7, P < 0.01), VPT (V; 5.4 ± 3.0 vs. 10.6 ± 10.3 vs. 17.7 ± 11.8, P < 0.01), WT (°C; 37.7 ± 3.5 vs. 39.1 ± 5.1 vs. 41.7 ± 4.7, P < 0.05), and a significant decrease in SSNCV (m/s; 50.2 ± 5.4 vs. 48.4 ± 5.0 vs. 39.5 ± 10.6, P < 0.05), CNFD (fibers/mm2; 37.8 ± 4.9 vs. 29.7 ± 7.7 vs. 27.1 ± 9.9, P < 0.01), CNFL (mm/mm2; 27.5 ± 3.6 vs. 24.4 ± 7.8 vs. 20.7 ± 7.1, P < 0.01), and IWL (mm/mm2; 35.1 ± 6.5 vs. 26.2 ± 10.5 vs. 23.6 ± 11.4, P < 0.05). For the diagnosis of DPN, CNFD, CNFL, and IWL achieved an area under the curve (AUC) of 0.75, 0.74, and 0.70, respectively, and a combination of IWL-CNFD achieved an AUC of 0.76. Conclusions. The parameters of CNFD, CNFL, and IWL have a comparable ability to diagnose patients with DPN. However, IWL

  10. Critical interpretation of CH– and OH– stretching regions for infrared spectra of methanol clusters (CH{sub 3}OH){sub n} (n = 2–5) using self-consistent-charge density functional tight-binding molecular dynamics simulations

    SciTech Connect

    Nishimura, Yoshifumi; Lee, Yuan-Pern; Irle, Stephan; Witek, Henryk A.

    2014-09-07

    Vibrational infrared (IR) spectra of gas-phase O–H⋅⋅⋅O methanol clusters up to pentamer are simulated using self-consistent-charge density functional tight-binding method using two distinct methodologies: standard normal mode analysis and Fourier transform of the dipole time-correlation function. The twofold simulations aim at the direct critical assignment of the C–H stretching region of the recently recorded experimental spectra [H.-L. Han, C. Camacho, H. A. Witek, and Y.-P. Lee, J. Chem. Phys. 134, 144309 (2011)]. Both approaches confirm the previous assignment (ibid.) of the C–H stretching bands based on the B3LYP/ANO1 harmonic frequencies, showing that ν{sub 3}, ν{sub 9}, and ν{sub 2} C–H stretching modes of the proton-accepting (PA) and proton-donating (PD) methanol monomers experience only small splittings upon the cluster formation. This finding is in sharp discord with the assignment based on anharmonic B3LYP/VPT2/ANO1 vibrational frequencies (ibid.), suggesting that some procedural faults, likely related to the breakdown of the perturbational vibrational treatment, led the anharmonic calculations astray. The IR spectra based on the Fourier transform of the dipole time-correlation function include new, previously unaccounted for physical factors such as non-zero temperature of the system and large amplitude motions of the clusters. The elevation of temperature results in a considerable non-homogeneous broadening of the observed IR signals, while the presence of large-amplitude motions (methyl group rotations and PA-PD flipping), somewhat surprisingly, does not introduce any new features in the spectrum.

  11. Two paramagnetic iron states at the Verwey phase transition in magnetite

    NASA Astrophysics Data System (ADS)

    Stankowski, J.; Kempiński, W.; Łoś, S.; Bednarski, W.; Waplak, S.; Micnas, R.

    2006-06-01

    At the Verwey phase transition (VPT) region a wide line of the ferromagnetic resonance (FMR) and a narrow EPR spectrum were observed. The EPR line at 125 K occurred and then disappeared below 85 K. This unexpected phenomenon is observed only if iron charge state transformation is present. Simulation of both FMR as well as EPR spectra has indicated the presence of two different iron clusters in the Fe 3O 4 structure. Best fit of both spectra yielded g=2.4 and 4.1 for FMR, and g=2.8 and 3.4 for EPR. The presence of two-component (EPR, FMR) spectra at about T is due to a frustration of charge distribution in the B-sublattice as a result of the orthorhombic Pmca pseudosymmetry constraints on the atomic positions in monoclinic symmetry cell P2/c. The paramagnetic (EPR) center observed is an admixtured Fe 2+ state in antiferromagnetically ordered A-sublattice ferromagnetically coupled with the B-lattice. Two paramagnetic defects observed (EPR) of localized spin states are evoked by two valency states of Fe 2.4 and Fe 2.6 below T. They can originate from two types of Fe 4O 4 cubes: "electron-rich" and" electron-poor" at a ratio 3:1 [J.P. Wright, J.P. Attfield, P.G. Radaelli, Phys. Rev. Lett. 87 (2001) 266401; Phys. Rev. B 66 (2002) 214422] or from two types of bond dimerization (H. Seo, M. Ogata, H. Fukuyama, Phys. Rev. B65 (2002) 85107).

  12. Bile salt-stimulated lipase of human milk: characterization of the enzyme from preterm and term milk

    SciTech Connect

    Freed, L.M.; Hamosh, P.; Hamosh, M.

    1986-03-01

    The bile salt-stimulated lipase (BSSL) of human milk is an important digestive enzyme in the newborn whose pancreatic function is immature. Milk from mothers delivering premature infants (preterm milk) has similar levels of BSSL activity to that of mothers of term infants (term milk). This study has determined whether the BSSL in preterm milk has the same characteristics as that in term milk. Milk samples were collected during the first 12 wk of lactation from seven mothers of infants born at 26-30 wk (very preterm, VPT), 31-37 wk (preterm, PT) and 37-42 wk (term, T) gestation. BSSL activity was measured using /sup 3/H-triolein emulsion as substrate. Time course, bile salt and enzyme concentration, pH and pH stability were studied, as well as inhibition of BSSL by eserine. The characteristics of BSSL from preterm and term milk were identical as were comparisons between colostrum and mature milk BSSL. BSSL from all milk sources had a neutral-to-alkaline pH optimum (pH 7.3-8.9), was stable at low pH for 60 min, and was 95-100% inhibited by eserine (greater than or equal to 0.6 mM). BSSL activity, regardless of enzyme source, was bile-salt dependent and was stimulated only by primary bile salts (taurocholate, glycocholate). The data indicate that the BSSL in milks of mothers delivering as early as 26 wk gestation is identical to that in term milk.

  13. Spectroscopic Studies of Molecular Systems relevant in Astrobiology

    NASA Astrophysics Data System (ADS)

    Fornaro, Teresa

    2016-01-01

    double-ζ quality such as N07D and SNSD. Such a protocol has been then applied to the dimers of nucleobases in order to study the perturbation on the vibrational frequencies and infrared intensities induced by the intermolecular hydrogen-bonding interactions. Efforts have been made to challenge the problems of simulating strongly anharmonic vibrations within hydrogen-bonded bridges, focusing on the requirement of a very accurate description of the underlying potential energy surface. Improvements for such vibrations have been achieved by means of hybrid models, where the harmonic part of the force-field is computed at a higher level of theory like B2PLYP, or by application of the less demanding ONIOM B2PLYP:B3LYP scheme, which is a focused model where only the part of the molecular system forming the hydrogen bonds is treated at B2PLYP level of theory. Moreover, for improving the vibrational frequencies of modes like the stretching of C=O and N-H functional groups, which are particularly sensitive to hydrogen-bonding, correction parameters for the B3LYP-D3/N07D frequencies have been determined. Afterwards, the treatment of the vibrational properties of nucleobases in condensed phases has been faced, focusing on uracil in the solid state. In particular, a heptamer cluster of uracil molecules has been considered as model to represent the properties in the solid state. The relative vibrational frequencies have been computed at anharmonic level within the VPT2 framework, combining two cost-effective approaches, namely the hybrid B3LYP-D3/N07D:DFTBA model, where the harmonic frequencies are computed with B3LYP-D3/N07D method and the anharmonic corrections are evaluated with the less expensive DFTBA method, and the reduced dimensionality VPT2 (RD-VPT2) approach, in which only selected vibrational modes are calculated anharmonically (including the couplings with the other modes) while the remaining modes are treated at the harmonic level, using the B3LYP-D3/N07D method only

  14. Spectroscopic Studies of Molecular Systems relevant in Astrobiology

    NASA Astrophysics Data System (ADS)

    Fornaro, Teresa

    2016-01-01

    double-ζ quality such as N07D and SNSD. Such a protocol has been then applied to the dimers of nucleobases in order to study the perturbation on the vibrational frequencies and infrared intensities induced by the intermolecular hydrogen-bonding interactions. Efforts have been made to challenge the problems of simulating strongly anharmonic vibrations within hydrogen-bonded bridges, focusing on the requirement of a very accurate description of the underlying potential energy surface. Improvements for such vibrations have been achieved by means of hybrid models, where the harmonic part of the force-field is computed at a higher level of theory like B2PLYP, or by application of the less demanding ONIOM B2PLYP:B3LYP scheme, which is a focused model where only the part of the molecular system forming the hydrogen bonds is treated at B2PLYP level of theory. Moreover, for improving the vibrational frequencies of modes like the stretching of C=O and N-H functional groups, which are particularly sensitive to hydrogen-bonding, correction parameters for the B3LYP-D3/N07D frequencies have been determined. Afterwards, the treatment of the vibrational properties of nucleobases in condensed phases has been faced, focusing on uracil in the solid state. In particular, a heptamer cluster of uracil molecules has been considered as model to represent the properties in the solid state. The relative vibrational frequencies have been computed at anharmonic level within the VPT2 framework, combining two cost-effective approaches, namely the hybrid B3LYP-D3/N07D:DFTBA model, where the harmonic frequencies are computed with B3LYP-D3/N07D method and the anharmonic corrections are evaluated with the less expensive DFTBA method, and the reduced dimensionality VPT2 (RD-VPT2) approach, in which only selected vibrational modes are calculated anharmonically (including the couplings with the other modes) while the remaining modes are treated at the harmonic level, using the B3LYP-D3/N07D method only

  15. Infrared absorption of methanol clusters (CH3OH)n with n = 2-6 recorded with a time-of-flight mass spectrometer using infrared depletion and vacuum-ultraviolet ionization.

    PubMed

    Han, Hui-Ling; Camacho, Cristopher; Witek, Henryk A; Lee, Yuan-Pern

    2011-04-14

    We investigated IR spectra in the CH- and OH-stretching regions of size-selected methanol clusters, (CH(3)OH)(n) with n = 2-6, in a pulsed supersonic jet by using the IR-VUV (vacuum-ultraviolet) ionization technique. VUV emission at 118 nm served as the source of ionization in a time-of-flight mass spectrometer. The tunable IR laser emission served as a source of predissociation or excitation before ionization. The variations of intensity of protonated methanol cluster ions (CH(3)OH)(n)H(+) and CH(3)OH(+) and (CH(3)OH)(2)(+) were monitored as the IR laser light was tuned across the range 2650-3750 cm(-1). Careful processing of these action spectra based on photoionization efficiencies and the production and loss of each cluster due to photodissociation yielded IR spectra of the size-selected clusters. Spectra of methanol clusters in the OH region have been extensively investigated; our results are consistent with previous reports, except that the band near 3675 cm(-1) is identified as being associated with the proton acceptor of (CH(3)OH)(2). Spectra in the CH region are new. In the region 2800-3050 cm(-1), bands near 2845, 2956, and 3007 cm(-1) for CH(3)OH split into 2823, 2849, 2934, 2955, 2984, and 3006 cm(-1) for (CH(3)OH)(2) that correspond to proton donor and proton acceptor, indicating that the methanol dimer has a preferred open-chain structure. In contrast, for (CH(3)OH)(3), the splitting diminishes and the bands near 2837, 2954, and 2987 cm(-1) become narrower, indicating a preferred cyclic structure. Anharmonic vibrational wavenumbers predicted for the methanol open-chain dimer and the cyclic trimer with the B3LYP∕VPT2∕ANO1 level of theory are consistent with experimental results. For the tetramer and pentamer, the spectral pattern similar to that of the trimer but with greater widths was observed, indicating that the most stable structures are also cyclic.

  16. Reliable vibrational wavenumbers for C=O and N-H stretchings of isolated and hydrogen-bonded nucleic acid bases.

    PubMed

    Fornaro, Teresa; Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo

    2016-03-28

    The accurate prediction of vibrational wavenumbers for functional groups involved in hydrogen-bonded bridges remains an important challenge for computational spectroscopy. For the specific case of the C=O and N-H stretching modes of nucleobases and their oligomers, the paucity of experimental reference values needs to be compensated by reliable computational data, which require the use of approaches going beyond the standard harmonic oscillator model. Test computations performed for model systems (formamide, acetamide and their cyclic homodimers) in the framework of the second order vibrational perturbation theory (VPT2) confirmed that anharmonic corrections can be safely computed by global hybrid (GHF) or double hybrid (DHF) functionals, whereas the harmonic part is particularly challenging. As a matter of fact, GHFs perform quite poorly and even DHFs, while fully satisfactory for C=O stretchings, face unexpected difficulties when dealing with N-H stretchings. On these grounds, a linear regression for N-H stretchings has been obtained and validated for the heterodimers formed by 4-aminopyrimidine with 6-methyl-4-pyrimidinone (4APM-M4PMN) and by uracil with water. In view of the good performance of this computational model, we have built a training set of B2PLYP-D3/maug-cc-pVTZ harmonic wavenumbers (including linear regression scaling for N-H) for six-different uracil dimers and a validation set including 4APM-M4PMN, one of the most stable hydrogen-bonded adenine homodimers, as well as the adenine-uracil, adenine-thymine, guanine-cytosine and adenine-4-thiouracil heterodimers. Because of the unfavourable scaling of DHF harmonic wavenumbers with the dimensions of the investigated systems, we have optimized a linear regression of B3LYP-D3/N07D harmonic wavenumbers for the training set, which has been next checked against the validation set. This relatively cheap model, which shows very good agreement with experimental data (average errors of about 10 cm(-1)), paves

  17. Monitoring the internal structure of poly(N-vinylcaprolactam) microgels with variable cross-link concentration.

    PubMed

    Schneider, Florian; Balaceanu, Andreea; Feoktystov, Artem; Pipich, Vitaliy; Wu, Yaodong; Allgaier, Jürgen; Pyckhout-Hintzen, Wim; Pich, Andrij; Schneider, Gerald J

    2014-12-23

    The combination of a set of complementary techniques allows us to construct an unprecedented and comprehensive picture of the internal structure, temperature dependent swelling behavior, and the dependence of these properties on the cross-linker concentration of microgel particles based on N-vinylcaprolactam (VCL). The microgels were synthesized by precipitation polymerization using different amounts of cross-linking agent. Characterization was performed by small-angle neutron scattering (SANS) using two complementary neutron instruments to cover a uniquely broad Q-range with one probe. Additionally we used dynamic light scattering (DLS), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). Previously obtained nuclear magnetic resonance spectroscopy (NMR) results on the same PVCL particles are utilized to round the picture off. Our study shows that both the particle radius and the cross-link density and therefore also the stiffness of the microgels rises with increasing cross-linker content. Hence, more cross-linker reduces the swelling capability distinctly. These findings are supported by SANS and AFM measurements. Independent DLS experiments also found the increase in particle size but suggest an unchanged cross-link density. The reason for the apparent contradiction is the indirect extraction of the parameters via a model in the evaluation of DLS measurements. The more direct approach in AFM by evaluating the cross section profiles of observed microgel particles gives evidence of significantly softer and more deformable particles at lower cross-linker concentrations and therefore verifies the change in cross-link density. DSC data indicate a minor but unexpected shift of the volume phase transition temperature (VPTT) to higher temperatures and exposes a more heterogeneous internal structure of the microgels with increasing cross-link density. Moreover, a change in the total energy transfer during the VPT gives evidence that the strength

  18. High-speed dual Langmuir probe.

    PubMed

    Lobbia, Robert B; Gallimore, Alec D

    2010-07-01

    In an effort to temporally resolve the electron density, electron temperature, and plasma potential for turbulent plasma discharges, a unique high-speed dual Langmuir probe (HDLP) has been developed. A traditional single Langmuir probe of cylindrical geometry (exposed to the plasma) is swept simultaneously with a nearby capacitance and noise compensating null probe (fully insulated from the plasma) to enable bias sweep rates on a microsecond timescale. Traditional thin-sheath Langmuir probe theory is applied for interpretation of the collected probe data. Data at a sweep rate of 100 kHz are presented; however the developed system is capable of running at 1 MHz-near the upper limit of the applied electrostatic Langmuir probe theory for the investigated plasma conditions. Large sets (100,000 sweeps at each of 352 spatial locations) of contiguous turbulent plasma properties are collected using simple electronics for probe bias driving and current measurement attaining 80 dB signal-to-noise measurements with dc to 1 MHz bandwidth. Near- and far-field plume measurements with the HDLP system are performed downstream from a modern Hall effect thruster where the time-averaged plasma properties exhibit the approximate ranges: electron density n(e) from (1x10(15))-(5x10(16)) m(-3), electron temperature T(e) from 1 to 3.5 eV, and plasma potential V(p) from 5 to 15 V. The thruster discharge of 200 V (constant anode potential) and 2 A (average discharge current) displays strong, 2.2 A peak-to-peak, current oscillations at 19 kHz, characteristic of the thruster "breathing mode" ionization instability. Large amplitude discharge current fluctuations are typical for most Hall thrusters, yet the HDLP system reveals the presence of the same 19 kHz fluctuations in n(e)(t), T(e)(t), and V(p)(t) throughout the entire plume with peak-to-peak divided by mean plasma properties that average 94%. The propagation delays between the discharge current fluctuations and the corresponding plasma

  19. 'Geoba-Raman-try': calibration of spectroscopic barometers for mineral inclusions (Invited)

    NASA Astrophysics Data System (ADS)

    Kohn, M. J.

    2013-12-01

    Determination of pressure-temperature (P-T) conditions of mineral formation underpins many crustal and mantle petrogenetic endeavors. Trace element thermometry has vastly improved T constraints, but P remains elusive and is still mainly based on solid state net-transfer reactions restricted to particular assemblages and whole-rock compositions. Novel Raman micro-spectroscopy may expand the range of geobarometers. At the P-T conditions of entrapment, no pressure mismatch occurs between inclusion and host (ΔP = 0). During cooling and exhumation, however, different thermal expansivities and compressibilities between host and inclusions impart a residual pressure (ΔP≠0) whose magnitude depends on entrapment P-T, V(P,T) and the shear modulus of the host phase. Many Raman peak positions are P-dependent, allowing ΔP to be measured. Based on shear moduli and V(P,T) (Holland & Powell, 2011, JMG), and assuming inclusions are small so that the host behaves as an infinite medium, a distribution of P-T-ΔP conditions may be calculated for various host-inclusion pairs and fit to simplified barometric calibrations. Distributions were calculated over P=0 to 25 kbar and T=400 to 900 °C for α-quartz- and graphite-bearing assemblages and P=35 to 150 kbar and T=800 to 1400 °C for diamond-bearing assemblages. These lead to the following calibrations (P in bars, T in K): Graphite-in-Grt (GriG): P = 1.491ΔP+1.129T+184*exp(ΔP/(9T))-1197 Qtz-in-Grt (QuiG): P = 0.8586ΔP+18.31T+12922*exp(ΔP/(27T))-21615 MgGrt-in-Dia (GriD, <90 kb): P = 2.07ΔP+50.8T+971*exp(ΔP/(15T))-13881 MgGrt-in-Dia (GriD, >90 kb): P = 2.31ΔP+52.0T+363*exp(ΔP/(15T))-18327 Coe-in-Dia (CoiD, <90 kb): P = 1.56ΔP+2.82T+143.7*exp(ΔP/(15T))-532 Coe-in-Dia (CoiD, >90 kb): P = 1.82ΔP-0.68T+13.54*exp(ΔP/(15T))-8197 Qtz-in-Omp (QuiO): P = 1.027ΔP+18.52T+10043*exp(ΔP/(17T))-18975 Qtz-in-Rt (QuiR): P = 0.7537ΔP+17.73T+14793*exp(ΔP/(26T))-23379 Qtz-in-Zrc (QuiZ): P = 1.007ΔP+20.32T+8108*exp(ΔP/(26T))-16410 For

  20. Chemomechanical properties and the applications of semi-confined hydrogel microstructures

    NASA Astrophysics Data System (ADS)

    Ding, Zhenwen

    Environmentally sensitive hydrogels are three-dimensional crosslinked polymer networks capable of undergoing reversible volume change in response to different stimuli such as temperature, pH, ionic strength, electric field, etc. The integration of these soft polymeric materials with conventional micromachined hard materials (such as silicon and glass) offers unique opportunities to enhance their applications and functionalities. Many such applications require the hydrogel to be trapped in a semi-confined structure. This calls for a careful study of hydrogel thermodynamics, kinetics, and chemomechanical properties associated with such a confinement. This physiochemical understanding is essential in order to design hydrogel-based smart sensing and actuating microdevices. This Ph.D. thesis consists of two parts. The first part will be focused on the physical concepts and measurements of the physical parameters of hydrogels. We will discuss the hydrogel network structure, kinetics of hydrogel volume phase transition (VPT), biomolecule diffusion in hydrogel network, and characterizations of hydrogel properties. In the second part, we will discuss the applications of semi-confined hydrogel structures in microsystems. A high-resolution technique for fabricating hydrogel microstructures will be presented. In this method, squeeze-film is used to generate hydrogel thin film on a smooth substrate. Parylene passivation and dry etching are utilized for micropatterning. This method allows for the integration of hydrogel with MEMS and NEMS microstructures in order to fabricate miniaturized devices for sensing and actuating. Subsequently, two applications will be discussed using the patterning technique: a hydrogel diffraction grating and a hydrogel-based integrated-antenna pH sensor. Microscale patterning of biomolecules (DNA, antibody, enzyme, etc.) on solid surfaces is necessary for the successful development of many biotechnological microdevices. We developed a hydrogel

  1. Integrated Cooling System for Induction Motor Traction Drives, CARAT Program Phase Two Final Report

    SciTech Connect

    Konrad, Charles E.

    2002-12-03

    This Program is directed toward improvements in electric vehicle/hybrid electric vehicle traction systems, and in particular, the development of a low cost, highly efficient, compact traction motor-controller system targeted for high volume automotive use. Because of the complex inter-relationships between the motor and the controller, the combination of motor and controller must be considered as a system in the design and evaluation of overall cost and performance. The induction motor is ideally suited for use as a traction motor because of its basic ruggedness, low cost, and high efficiency. As one can see in Figure 1.1, the induction motor traction drive has been continually evolving through a succession of programs spanning the past fifteen years. VPT marketed an induction motor-based traction drive system, the EV2000, which proved to be a reliable, high performance system that was used in a wide range of vehicles. The EV2000 drives evolved from the Modular Electric Vehicle Program (MEVP) and has been used in vehicles ranging in size from 3,000 lb. autos and utility vans, to 32,000 lb. city transit buses. Vehicles powered by the EV2000 induction motor powertrain have accumulated over 2 million miles of service. The EV2000 induction motor system represents 1993 state-of-the-art technology, and evolved from earlier induction motor programs that drove induction motor speeds up to 15,000 rpm to reduce the motor size and cost. It was recognized that the improvements in power density and motor cost sought in the PNGV program could only be achieved through increases in motor speed. Esson’s Rule for motor power clearly states that the power obtainable from a given motor design is the product of motor speed and volume. In order to meet the CARAT Program objectives, the maximum speed goal of the induction motor designed in this Program was increased from 15,000 rpm to 20,000 rpm while maintaining the efficiency and durability demonstrated by lower speed designs done in

  2. Stabile Expression von Sulfotransferasen - allein oder in Kombination mit Cytochrom P450 - in Zelllinien für Mutagenitätsuntersuchungen

    NASA Astrophysics Data System (ADS)

    Pabel, Ulrike

    2003-10-01

    -dimethylaminoazobenzol; 0,1 µM für 2-Aminoanthracen; 10 µM für 2,4-Diaminotoluol). Die stärkste Aktivierung von 2-Acetylaminofluoren und 3′-Methyl-4-dimethylaminoazobenzol erfolgte in der Zelllinie, die CYP1A2 und SULT1A2 koexprimierte; die stärkste Aktivierung von 2,4-Diaminotoluol und 2-Aminoanthracen erfolgte in der Zelllinie, die CYP1A2 und SULT1A1 koexprimierte. Sowohl SULT1A1 als auch SULT1A2 sind im Menschen genetisch polymorph. Ein unterschiedlich starkes Aktivierungspotenzial der Alloenzyme könnte eine individuell unterschiedliche Suszeptibilität für die durch aAA ausgelöste Kanzerogenese bedingen. In HPRT-Mutationsuntersuchungen mit rekombinanten Zellen zeigten die allelischen Varianten der SULT1A2 starke Unterschiede in ihrem Aktivierungpotenzial. Nur in der Zelllinie, die das Alloenzym SULT1A2*1 mit CYP1A2 koexprimierte, wurde 2-Acetylaminofluoren zum Mutagen aktiviert. Zur Aktivierung von 3′-Methyl-4-dimethylaminoazobenzol waren jedoch sowohl das Alloenzym SULT1A2*1 als auch das Alloenzym SULT1A2*2 in der Lage. Die Alloenzyme der SULT1A1 zeigten ein ähnlich gutes Aktivierungspotenzial für aAA. In früheren Studien wurde gezeigt, dass die SULT1C1 der Ratte eine wichtige Rolle bei der Aktivierung der aAA in dieser Spezies spielt. Dahingegen war die humane SULT1C1 nicht in der Lage die untersuchten aAA zu aktivieren. Die Kenntnis solcher Spezieunterschiede könnte wichtig sein um unterschiedliche Organotropismen aAA in Menschen und Tiermodellen zu erklären, da SULT mit starker Gewebespezifität exprimiert werden und das Expressionsmuster für die einzelnen SULT-Formen in Menschen und Ratten sich stark unterscheidet. Aromatic amines and amides (aAA) represent a group of chemicals with great toxicological importance due to their wide distribution in the environment and their carcinogenic potency. The carcinogenicity of aAA is mediated by the mutagenic action of highly reactive metabolites. They are frequently formed by N-hydroxylation of the exocyclic

  3. Growth

    NASA Astrophysics Data System (ADS)

    Waag, Andreas

    This chapter is devoted to the growth of ZnO. It starts with various techniques to grow bulk samples and presents in some detail the growth of epitaxial layers by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), and pulsed laser deposition (PLD). The last section is devoted to the growth of nanorods. Some properties of the resulting samples are also presented. If a comparison between GaN and ZnO is made, very often the huge variety of different growth techniques available to fabricate ZnO is said to be an advantage of this material system. Indeed, growth techniques range from low cost wet chemical growth at almost room temperature to high quality MOCVD growth at temperatures above 1, 000∘C. In most cases, there is a very strong tendency of c-axis oriented growth, with a much higher growth rate in c-direction as compared to other crystal directions. This often leads to columnar structures, even at relatively low temperatures. However, it is, in general, not straight forward to fabricate smooth ZnO thin films with flat surfaces. Another advantage of a potential ZnO technology is said to be the possibility to grow thin films homoepitaxially on ZnO substrates. ZnO substrates are mostly fabricated by vapor phase transport (VPT) or hydrothermal growth. These techniques are enabling high volume manufacturing at reasonable cost, at least in principle. The availability of homoepitaxial substrates should be beneficial to the development of ZnO technology and devices and is in contrast to the situation of GaN. However, even though a number of companies are developing ZnO substrates, only recently good quality substrates have been demonstrated. However, these substrates are not yet widely available. Still, the situation concerning ZnO substrates seems to be far from low-cost, high-volume production. The fabrication of dense, single crystal thin films is, in general, surprisingly difficult, even when ZnO is grown on a ZnO substrate. However

  4. AAS 228: Day 1 morning

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    occur at different times and have different depths in the light curve each time they orbit. Their misalignment may have been caused by a past collision with another planet, which was kicked out of the system in the process. The LIGO-VIRGO Forum on Hunting Gravitational Wave Counterparts(by Gourav Khullar)This parallel session, organized by Peter Shawhan (University of Maryland, advancedLIGO) discussed the first major followup campaign of the GW150914 gravitational wave (GW) discovery event by the physics and astronomy community around the world. It was extremely exciting to hear the speakers talk of the actual process behind the mega-collaborative effort following the first GW event. This paper, published on June 3rd this year, was described by Peter, with a strong emphasis on the timeline following the GW alert in raw LIGO data back in September 2015, along with description of the sky map and raw data given to different facilities and collaborations that LIGO-VIRGO had signed Memorandums of Understanding (MOUs) with for rapid and robust followups. The talk also focussed on resources and tutorials available now to unpack and characterize future alerts data from LIGO-VIRGO. This talk was followed by the description of the all sky survey PAN-STARRS, and its joint efforts with LIGO. It was pointed out that PAN-STARRS had already scanned the sky multiple times, which gave the program an edge in determining transients, i.e. recent features appearing on their new maps but not the old. This extensive survey also allowed better characterization of the transient source, which would be the next step for PAN-STARRS and other similar projects. Our @LIGO booth at #AAS228 is up and running drop by for a chat about #gravitationalwaves pic.twitter.com/akt9wsVPT6 pic.twitter.com/kmPz3oxzJf LIGO (@LIGO) June 13, 2016Following this was a talk by Andy Howell, of the newly formed Las Cumbres Observatory A Global Telescope Network (LCOGT), made up of multiple telescopes across the US, Chile