Vibrational energy levels for CH4 from an ab initio potential

NASA Technical Reports Server (NTRS)

Schwenke, D. W.; Partridge, H.

2001-01-01

Many areas of astronomy and astrophysics require an accurate high temperature spectrum of methane (CH4). The goal of the present research is to determine an accurate ab initio potential energy surface (PES) for CH4. As a first step towards this goal, we have determined a PES including up to octic terms. We compare our results with experiment and to a PES based on a quartic expansion. Our octic PES gives good agreement with experiment for all levels, while the quartic PES only for the lower levels.

Neural networks vs Gaussian process regression for representing potential energy surfaces: A comparative study of fit quality and vibrational spectrum accuracy

NASA Astrophysics Data System (ADS)

Kamath, Aditya; Vargas-Hernández, Rodrigo A.; Krems, Roman V.; Carrington, Tucker; Manzhos, Sergei

2018-06-01

For molecules with more than three atoms, it is difficult to fit or interpolate a potential energy surface (PES) from a small number of (usually ab initio) energies at points. Many methods have been proposed in recent decades, each claiming a set of advantages. Unfortunately, there are few comparative studies. In this paper, we compare neural networks (NNs) with Gaussian process (GP) regression. We re-fit an accurate PES of formaldehyde and compare PES errors on the entire point set used to solve the vibrational Schrödinger equation, i.e., the only error that matters in quantum dynamics calculations. We also compare the vibrational spectra computed on the underlying reference PES and the NN and GP potential surfaces. The NN and GP surfaces are constructed with exactly the same points, and the corresponding spectra are computed with the same points and the same basis. The GP fitting error is lower, and the GP spectrum is more accurate. The best NN fits to 625/1250/2500 symmetry unique potential energy points have global PES root mean square errors (RMSEs) of 6.53/2.54/0.86 cm-1, whereas the best GP surfaces have RMSE values of 3.87/1.13/0.62 cm-1, respectively. When fitting 625 symmetry unique points, the error in the first 100 vibrational levels is only 0.06 cm-1 with the best GP fit, whereas the spectrum on the best NN PES has an error of 0.22 cm-1, with respect to the spectrum computed on the reference PES. This error is reduced to about 0.01 cm-1 when fitting 2500 points with either the NN or GP. We also find that the GP surface produces a relatively accurate spectrum when obtained based on as few as 313 points.

Rotational Energy Transfer of N2 Determined Using a New Ab Initio Potential Energy Surface

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

1997-01-01

A new N2-N2 rigid-rotor surface has been determined using extensive Ab Initio quantum chemistry calculations together with recent experimental data for the second virial coefficient. Rotational energy transfer is studied using the new potential energy surface (PES) employing the close coupling method below 200 cm(exp -1) and coupled state approximation above that. Comparing with a previous calculation based on the PES of van der Avoird et al.,3 it is found that the new PES generally gives larger cross sections for large (delta)J transitions, but for small (delta)J transitions the cross sections are either comparable or smaller. Correlation between the differences in the cross sections and the two PES will be attempted. The computed cross sections will also be compared with available experimental data.

Global potential energy surface of ground state singlet spin O4

NASA Astrophysics Data System (ADS)

Mankodi, Tapan K.; Bhandarkar, Upendra V.; Puranik, Bhalchandra P.

2018-02-01

A new global potential energy for the singlet spin state O4 system is reported using CASPT2/aug-cc-pVTZ ab initio calculations. The geometries for the six-dimensional surface are constructed using a novel point generation scheme that employs randomly generated configurations based on the beta distribution. The advantage of this scheme is apparent in the reduction of the number of required geometries for a reasonably accurate potential energy surface (PES) and the consequent decrease in the overall computational effort. The reported surface matches well with the recently published singlet surface by Paukku et al. [J. Chem. Phys. 147, 034301 (2017)]. In addition to the O4 PES, the ground state N4 PES is also constructed using the point generation scheme and compared with the existing PES [Y. Paukku et al., J. Chem. Phys. 139, 044309 (2013)]. The singlet surface is constructed with the aim of studying high energy O2-O2 collisions and predicting collision induced dissociation cross section to be used in simulating non-equilibrium aerothermodynamic flows.

Taboo search by successive confinement: Surveying a potential energy surface

NASA Astrophysics Data System (ADS)

Chekmarev, Sergei F.

2001-09-01

A taboo search for minima on a potential energy surface (PES) is performed by means of confinement molecular dynamics: the molecular dynamics trajectory of the system is successively confined to various basins on the PES that have not been sampled yet. The approach is illustrated for a 13-atom Lennard-Jones cluster. It is shown that the taboo search radically accelerates the process of surveying the PES, with the probability of finding a new minimum defined by a propagating Fermi-like distribution.

Antifouling polyethersulfone hemodialysis membranes incorporated with poly (citric acid) polymerized multi-walled carbon nanotubes.

PubMed

Abidin, Muhammad Nidzhom Zainol; Goh, Pei Sean; Ismail, Ahmad Fauzi; Othman, Mohd Hafiz Dzarfan; Hasbullah, Hasrinah; Said, Noresah; Kadir, Siti Hamimah Sheikh Abdul; Kamal, Fatmawati; Abdullah, Mohd Sohaimi; Ng, Be Cheer

2016-11-01

Poly (citric acid)-grafted-MWCNT (PCA-g-MWCNT) was incorporated as nanofiller in polyethersulfone (PES) to produce hemodialysis mixed matrix membrane (MMM). Citric acid monohydrate was polymerized onto the surface of MWCNTs by polycondensation. Neat PES membrane and PES/MWCNTs MMMs were fabricated by dry-wet spinning technique. The membranes were characterized in terms of morphology, pure water flux (PWF) and bovine serum albumin (BSA) protein rejection. The grafting yield of PCA onto MWCNTs was calculated as 149.2%. The decrease of contact angle from 77.56° to 56.06° for PES/PCA-g-MWCNTs membrane indicated the increase in surface hydrophilicity, which rendered positive impacts on the PWF and BSA rejection of the membrane. The PWF increased from 15.8Lm(-2)h(-1) to 95.36Lm(-2)h(-1) upon the incorporation of PCA-g-MWCNTs due to the attachment of abundant hydrophilic groups that present on the MWCNTs, which have improved the affinity of membrane towards the water molecules. For protein rejection, the PES/PCA-g-MWCNTs MMM rejected 95.2% of BSA whereas neat PES membrane demonstrated protein rejection of 90.2%. Compared to commercial PES hemodialysis membrane, the PES/PCA-g-MWCNTs MMMs showed less flux decline behavior and better PWF recovery ratio, suggesting that the membrane antifouling performance was improved. The incorporation of PCA-g-MWCNTs enhanced the separation features and antifouling capabilities of the PES membrane for hemodialysis application. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantal Study of the Exchange Reaction for N + N2 using an ab initio Potential Energy Surface

NASA Technical Reports Server (NTRS)

Wang, Dunyou; Stallcop, James R.; Huo, Winifred M.; Dateo, Christopher E.; Schwenke, David W.; Partridge, Harry; Kwak, Dochan (Technical Monitor)

2002-01-01

The N + N2 exchange rate is calculated using a time-dependent quantum dynamics method on a newly determined ab initio potential energy surface (PES) for the ground A" state. This ab initio PES shows a double barrier feature in the interaction region with the barrier height at 47.2 kcal/mol, and a shallow well between these two barriers, with the minimum at 43.7 kcal/mol. A quantum dynamics wave packet calculation has been carried out using the fitted PES to compute the cumulative reaction probability for the exchange reaction of N + N2(J=O). The J - K shift method is then employed to obtain the rate constant for this reaction. The calculated rate constant is compared with experimental data and a recent quasi-classical calculation using a LEPS PES. Significant differences are found between the present and quasiclassical results. The present rate calculation is the first accurate 3D quantal dynamics study for N + N2 reaction system and the ab initio PES reported here is the first such surface for N3.

Characterization of Polydopamine-Coated Polyethersulfone (PES) membrane for water purification

NASA Astrophysics Data System (ADS)

Syawaliah; Mulyati, S.; Muzaitun; Mulyasari, R.

2018-05-01

The polyethersulfone (PES) membrane has been prepared by phase inversion method using N-methyl-2-pyrolidone (NMP) as solvent and polydopamine (PDA) as additive. The fabricated membrane was modified by coating with PDA of 0.5 g/l concentration and 180 minutes immersion time. The characteristic of the PES membranes before and after the modification was studied in this paper. The result of the pure water permeation experiment showed that the PDA-coated PES membrane showcased a higher flux than that of pure PES membrane. Scanning Electron Microscopy (SEM) analysis confirmed that the membrane had an asymmetric structure consisting of two layers. There was no significant influence on the addition of PDA to the morphology of the pore matrix because the modification was done by surface coating. Fourier Transform Infrared Spectroscopy (FTIR) analysis showed that PDA was successfully introduced on the surface of PES membrane with the appearance of peak O-H from catechol at wavenumber of 3348 cm-1. Modification with PDA increased the mechanical strength of the membrane which affirmed by the results of the tensile and elongation at break evaluation.

Preparation of Low fouling Polyethersulfone Membranes by Simultaneously Phase Separation and Redox Polymerization

NASA Astrophysics Data System (ADS)

Roihatin, A.; Susanto, H.

2017-05-01

This paper presents preparation of low fouling PES membranes by non solvent induced phase separation (NIPS) coupled with redox polymerization. The membrane characterization included water permeability, morphology structure (by SEM) and surface chemistry (by FTIR). Water permeability measurements showed thatthe membranes have water permeability within the range 10-50 L/h.m2.bar. Addition of PEG dan PEGMA intopolymer solution increased water permeability, whereas blending redox initiator and crosslinker, MBAA in polymer solution decreased water permeability. Surface morfology of membranes by SEM showed that unmodified PES membrane had smaller pore size than PEG or PEGMA modified PES membranes. Furthermore, PES-PEG or PES-PEGMA membranes modified by blending with redox initiator and MBAA as crosslinker showed smaller pore size than unmodified membrane. FTIR analysis showed that all membranes have typical spectraof PES polymer; however no additional peak was observed forthe membranes prepared with addition of PEG/PEGMA, initiator redox and also crosslinker. The addition of PEG/PEGMA, redox initiator and crosslinker resulted in membranes with high rejection and an acceptable flux as well as more stable due to relatively high fouling resistance.

Iron-tannin-framework complex modified PES ultrafiltration membranes with enhanced filtration performance and fouling resistance.

PubMed

Fang, Xiaofeng; Li, Jiansheng; Li, Xin; Pan, Shunlong; Sun, Xiuyun; Shen, Jinyou; Han, Weiqing; Wang, Lianjun; Van der Bruggen, Bart

2017-11-01

In this work, an iron-tannin-framework (ITF) complex was introduced to a poly (ether sulfone) (PES) casting solution as a hydrophilic additive to fabricate ITF/PES ultrafiltration (UF) membranes via non-solvent-induced phase separation (NIPS). The structure and performance of the PES membranes with ITF concentrations ranging from 0 to 0.9wt.% were systematically investigated by scanning electron microscopy, water contact angle, permeability, protein rejection and fouling resistance measurements. The results indicate that the pore structure and surface properties of PES UF membranes can be regulated by incorporating the ITF complex. Compared with classical PES membranes, ITF/PES membranes were found to have an increased hydrophilicity and porosity and reduced surface pore size. Importantly, a simultaneous enhancement of permeability and separation performance was observed for the blend membranes, which indicates that the introduction of the ITF complex can break through the trade-off between permeability and selectivity of UF membranes.When the ITF content was 0.3wt.%, the permeability reached a maximum of 319.4(L/m 2 h) at 0.1MPa, which is 1.6 times higher than that of the classical PES membrane. Furthermore, the BSA rejection increased from 25.9% for the PES membrane to 95.9% for the enhanced membrane. In addition, the same membrane showed an improved fouling resistance (higher flux recovery and lower adhesion force) and stable hydrophilicity (unchanged after incubation in deionized water for 30days). The simple, green and cost-effective preparation process and the outstanding filtration performance highlight the potential of ITF/PES membranes for practical applications. Copyright © 2017 Elsevier Inc. All rights reserved.

Eight-dimensional quantum reaction rate calculations for the H+CH{sub 4} and H{sub 2}+CH{sub 3} reactions on recent potential energy surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yong; Zhang, Dong H., E-mail: zhangdh@dicp.ac.cn

2014-11-21

Eight-dimensional (8D) transition-state wave packet simulations have been performed on two latest potential energy surfaces (PES), the Zhou-Fu-Wang-Collins-Zhang (ZFWCZ) PES [Y. Zhou, B. Fu, C. Wang, M. A. Collins, and D. H. Zhang, J. Chem. Phys. 134, 064323 (2011)] and the Xu-Chen-Zhang (XCZ)-neural networks (NN) PES [X. Xu, J. Chen, and D. H. Zhang, Chin. J. Chem. Phys. 27, 373 (2014)]. Reaction rate constants for both the H+CH{sub 4} reaction and the H{sub 2}+CH{sub 3} reaction are calculated. Simulations of the H+CH{sub 4} reaction based on the XCZ-NN PES show that the ZFWCZ PES predicts rate constants with reasonable highmore » accuracy for low temperatures while leads to slightly lower results for high temperatures, in line with the distribution of interpolation error associated with the ZFWCZ PES. The 8D H+CH{sub 4} rate constants derived on the ZFWCZ PES compare well with full-dimensional 12D results based on the equivalent m-ZFWCZ PES, with a maximum relative difference of no more than 20%. Additionally, very good agreement is shown by comparing the 8D XCZ-NN rate constants with the 12D results obtained on the ZFWCZ-WM PES, after considering the difference in static barrier height between these two PESs. The reaction rate constants calculated for the H{sub 2}+CH{sub 3} reaction are found to be in good consistency with experimental observations.« less

Kinetics study of the CN + CH4 hydrogen abstraction reaction based on a new ab initio analytical full-dimensional potential energy surface.

PubMed

Espinosa-Garcia, Joaquin; Rangel, Cipriano; Suleimanov, Yury V

2017-07-26

We have developed an analytical full-dimensional potential energy surface, named PES-2017, for the gas-phase hydrogen abstraction reaction between the cyano radical and methane. This surface is fitted using high-level ab initio information as input. Using the PES-2017 surface, a kinetics study was performed via two theoretical approaches: variational transition-state theory with multidimensional tunnelling (VTST-MT) and ring polymer molecular dynamics (RPMD). The results are compared with the experimental data. In the whole temperature range analysed, 300-1500 K, both theories agree within a factor of <2, reproducing the experimental behaviour taking into account the experimental uncertainties. At high temperatures, where the recrossing effects dominate and the RPMD theory is exact, both theories differ by a factor of about 20%; while at low temperatures this difference is larger, 45%. Note that in this temperature regime, the tunnelling effect is negligible. The CN + CH 4 /CD 4 kinetic isotope effects are important, reproducing the scarce experimental evidence. The good agreement with the ab initio information used in the fitting process (self-consistency test) and with the kinetic behaviour in a wide temperature range gives confidence and strength to the new surface.

Dynamics Sampling in Transition Pathway Space.

PubMed

Zhou, Hongyu; Tao, Peng

2018-01-09

The minimum energy pathway contains important information describing the transition between two states on a potential energy surface (PES). Chain-of-states methods were developed to efficiently calculate minimum energy pathways connecting two stable states. In the chain-of-states framework, a series of structures are generated and optimized to represent the minimum energy pathway connecting two states. However, multiple pathways may exist connecting two existing states and should be identified to obtain a full view of the transitions. Therefore, we developed an enhanced sampling method, named as the direct pathway dynamics sampling (DPDS) method, to facilitate exploration of a PES for multiple pathways connecting two stable states as well as addition minima and their associated transition pathways. In the DPDS method, molecular dynamics simulations are carried out on the targeting PES within a chain-of-states framework to directly sample the transition pathway space. The simulations of DPDS could be regulated by two parameters controlling distance among states along the pathway and smoothness of the pathway. One advantage of the chain-of-states framework is that no specific reaction coordinates are necessary to generate the reaction pathway, because such information is implicitly represented by the structures along the pathway. The chain-of-states setup in a DPDS method greatly enhances the sufficient sampling in high-energy space between two end states, such as transition states. By removing the constraint on the end states of the pathway, DPDS will also sample pathways connecting minima on a PES in addition to the end points of the starting pathway. This feature makes DPDS an ideal method to directly explore transition pathway space. Three examples demonstrate the efficiency of DPDS methods in sampling the high-energy area important for reactions on the PES.

An accurate global potential energy surface, dipole moment surface, and rovibrational frequencies for NH3

NASA Astrophysics Data System (ADS)

Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

2008-12-01

A global potential energy surface (PES) that includes short and long range terms has been determined for the NH3 molecule. The singles and doubles coupled-cluster method that includes a perturbational estimate of connected triple excitations and the internally contracted averaged coupled-pair functional electronic structure methods have been used in conjunction with very large correlation-consistent basis sets, including diffuse functions. Extrapolation to the one-particle basis set limit was performed and core correlation and scalar relativistic contributions were included directly, while the diagonal Born-Oppenheimer correction was added. Our best purely ab initio PES, denoted "mixed," is constructed from two PESs which differ in whether the ic-ACPF higher-order correlation correction was added or not. Rovibrational transition energies computed from the mixed PES agree well with experiment and the best previous theoretical studies, but most importantly the quality does not deteriorate even up to 10300cm-1 above the zero-point energy (ZPE). The mixed PES was improved further by empirical refinement using the most reliable J =0-2 rovibrational transitions in the HITRAN 2004 database. Agreement between high-resolution experiment and rovibrational transition energies computed from our refined PES for J =0-6 is excellent. Indeed, the root mean square (rms) error for 13 HITRAN 2004 bands for J =0-2 is 0.023cm-1 and that for each band is always ⩽0.06cm-1. For J =3-5 the rms error is always ⩽0.15cm-1. This agreement means that transition energies computed with our refined PES should be useful in the assignment of new high-resolution NH3 spectra and in correcting mistakes in previous assignments. Ideas for further improvements to our refined PES and for extension to other isotopolog are discussed.

Comparison of plantar pressures and contact area between normal and cavus foot.

PubMed

Fernández-Seguín, Lourdes M; Diaz Mancha, Juan Antonio; Sánchez Rodríguez, Raquel; Escamilla Martínez, Elena; Gómez Martín, Beatriz; Ramos Ortega, Javier

2014-02-01

In pes cavus, the medial longitudinal arch elevation reduces the contact surface area and consequently increases the corresponding plantar pressure measurements. This poor distribution of loads may produce associated pathology and pain in this or other areas of the body. Normal reference values need to be established in order to determine which patterns are prone to pathology. To compare the plantar pressures and weight-bearing surface in a population with pes cavus to a population with neutral feet. The sample comprised 68 adults, 34 with pes cavus and 34 with neutral feet. The Footscan USB Gait Clinical System(®) was used as a platform to measure the total contact area and plantar pressure under the forefoot, midfoot, hindfoot, each metatarsal head, and the overall metatarsal area. A statistical analysis of the data was performed using Student's t-test for independent samples. The pes cavus subjects showed a significant reduction in their weight-bearing area [neutral feet: 165.04 ( ± 20.68) cm(2); pes cavus: 118.26 ( ± 30.31) cm(2); p < 0.001] and significantly increased pressures under all zones of the forefoot except the fifth metatarsal [metatarsal pressure: in neutral feet 503,797 ( ± 9.32) kPa; in pes cavus 656.12 ( ± 22.39) kPa; p < 0.001]. Compared to neutral feet, pes cavus feet show a reduction in total contact surface and the load under the first toe. A significant increase is present in the load under the metatarsal areas, but the relative distribution of this load is similar in both groups. Copyright © 2013 Elsevier B.V. All rights reserved.

Fast Shepard interpolation on graphics processing units: potential energy surfaces and dynamics for H + CH4 → H2 + CH3.

PubMed

Welsch, Ralph; Manthe, Uwe

2013-04-28

A strategy for the fast evaluation of Shepard interpolated potential energy surfaces (PESs) utilizing graphics processing units (GPUs) is presented. Speed ups of several orders of magnitude are gained for the title reaction on the ZFWCZ PES [Y. Zhou, B. Fu, C. Wang, M. A. Collins, and D. H. Zhang, J. Chem. Phys. 134, 064323 (2011)]. Thermal rate constants are calculated employing the quantum transition state concept and the multi-layer multi-configurational time-dependent Hartree approach. Results for the ZFWCZ PES are compared to rate constants obtained for other ab initio PESs and problems are discussed. A revised PES is presented. Thermal rate constants obtained for the revised PES indicate that an accurate description of the anharmonicity around the transition state is crucial.

Sulfur-Doped Laser-Induced Porous Graphene Derived from Polysulfone-Class Polymers and Membranes.

PubMed

Singh, Swatantra P; Li, Yilun; Zhang, Jibo; Tour, James M; Arnusch, Christopher J

2018-01-23

Graphene based materials have profoundly impacted research in nanotechnology, and this has significantly advanced biomedical, electronics, energy, and environmental applications. Laser-induced graphene (LIG) is made photothermally and has enabled a rapid route for graphene layers on polyimide surfaces. However, polysulfone (PSU), poly(ether sulfone) (PES), and polyphenylsulfone (PPSU) are highly used in numerous applications including medical, energy, and water treatment and they are critical components of polymer membranes. Here we show LIG fabrication on PSU, PES, and PPSU resulting in conformal sulfur-doped porous graphene embedded in polymer dense films or porous substrates using reagent- and solvent-free methods in a single step. We demonstrate the applicability as flexible electrodes with enhanced electrocatalytic hydrogen peroxide generation, as antifouling surfaces and as antimicrobial hybrid membrane-LIG porous filters. The properties and surface morphology of the conductive PSU-, PES-, and PPSU-LIG could be modulated using variable laser duty cycles. The LIG electrodes showed enhanced hydrogen peroxide generation compared to LIG made on polyimide, and showed exceptional biofilm resistance and potent antimicrobial killing effects when treated with Pseudomonas aeruginosa and mixed bacterial culture. The hybrid PES-LIG membrane-electrode ensured complete elimination of bacterial viability in the permeate (6 log reduction), in a flow-through filtration mode at a water flux of ∼500 L m -2 h -1 (2.5 V) and at ∼22 000 L m -2 h -1 (20 V). Due to the widespread use of PSU, PES, and PPSU in modern society, these functional PSU-, PES-, and PPSU-LIG surfaces have great potential to be incorporated into biomedical, electronic, energy and environmental devices and technologies.

Full-dimensional analytical potential energy surface describing the gas-phase Cl + C2H6 reaction and kinetics study of rate constants and kinetic isotope effects.

PubMed

Rangel, Cipriano; Espinosa-Garcia, Joaquin

2018-02-07

Within the Born-Oppenheimer approximation a full-dimensional analytical potential energy surface, PES-2017, was developed for the gas-phase hydrogen abstraction reaction between the chlorine atom and ethane, which is a nine body system. This surface presents a valence-bond/molecular mechanics functional form dependent on 60 parameters and is fitted to high-level ab initio calculations. This reaction presents little exothermicity, -2.30 kcal mol -1 , with a low height barrier, 2.44 kcal mol -1 , and intermediate complexes in the entrance and exit channels. We found that the energetic description was strongly dependent on the ab initio level used and it presented a very flat topology in the entrance channel, which represents a theoretical challenge in the fitting process. In general, PES-2017 reproduces the ab initio information used as input, which is merely a test of self-consistency. As a first test of the quality of the PES-2017, a theoretical kinetics study was performed in the temperature range 200-1400 K using two approaches, i.e. the variational transition-state theory and quasi-classical trajectory calculations, with spin-orbit effects. The rate constants show reasonable agreement with experiments in the whole temperature range, with the largest differences at the lowest temperatures, and this behaviour agrees with previous theoretical studies, thus indicating the inherent difficulties in the theoretical simulation of the kinetics of the title reaction. Different sources of error were analysed, such as the limitations of the PES and theoretical methods, recrossing effects, and the tunnelling effect, which is negligible in this reaction, and the manner in which the spin-orbit effects were included in this non-relativistic study. We found that the variation of spin-orbit coupling along the reaction path, and the influence of the reactivity of the excited Cl( 2 P 1/2 ) state, have relative importance, but do not explain the whole discrepancy. Finally, the activation energy and the kinetics isotope effects reproduce the experimental information.

Water dissociating on rigid Ni(100): A quantum dynamics study on a full-dimensional potential energy surface

NASA Astrophysics Data System (ADS)

Liu, Tianhui; Chen, Jun; Zhang, Zhaojun; Shen, Xiangjian; Fu, Bina; Zhang, Dong H.

2018-04-01

We constructed a nine-dimensional (9D) potential energy surface (PES) for the dissociative chemisorption of H2O on a rigid Ni(100) surface using the neural network method based on roughly 110 000 energies obtained from extensive density functional theory (DFT) calculations. The resulting PES is accurate and smooth, based on the small fitting errors and the good agreement between the fitted PES and the direct DFT calculations. Time dependent wave packet calculations also showed that the PES is very well converged with respect to the fitting procedure. The dissociation probabilities of H2O initially in the ground rovibrational state from 9D quantum dynamics calculations are quite different from the site-specific results from the seven-dimensional (7D) calculations, indicating the importance of full-dimensional quantum dynamics to quantitatively characterize this gas-surface reaction. It is found that the validity of the site-averaging approximation with exact potential holds well, where the site-averaging dissociation probability over 15 fixed impact sites obtained from 7D quantum dynamics calculations can accurately approximate the 9D dissociation probability for H2O in the ground rovibrational state.

HCl dissociating on a rigid Au(111) surface: A six-dimensional quantum mechanical study on a new potential energy surface based on the RPBE functional.

PubMed

Liu, Tianhui; Fu, Bina; Zhang, Dong H

2017-04-28

The dissociative chemisorption of HCl on the Au(111) surface has recently been an interesting and important subject, regarding the discrepancy between the theoretical dissociation probabilities and the experimental sticking probabilities. We here constructed an accurate full-dimensional (six-dimensional (6D)) potential energy surface (PES) based on the density functional theory (DFT) with the revised Perdew-Burke-Ernzerhof (RPBE) functional, and performed 6D quantum mechanical (QM) calculations for HCl dissociating on a rigid Au(111) surface. The effects of vibrational excitations, rotational orientations, and site-averaging approximation on the present RPBE PES are investigated. Due to the much higher barrier height obtained on the RPBE PES than on the PW91 PES, the agreement between the present theoretical and experimental results is greatly improved. In particular, at the very low kinetic energy, the QM-RPBE dissociation probability agrees well with the experimental data. However, the computed QM-RPBE reaction probabilities are still markedly different from the experimental values at most of the energy regions. In addition, the QM-RPBE results achieve good agreement with the recent ab initio molecular dynamics calculations based on the RPBE functional at high kinetic energies.

Potential energy and dipole moment surfaces for HF@C60: Prediction of spectral and electric response properties

NASA Astrophysics Data System (ADS)

Kalugina, Yulia N.; Roy, Pierre-Nicholas

2017-12-01

We present a five-dimensional potential energy surface (PES) for the HF@C60 system computed at the DF-LMP2/cc-pVTZ level of theory. We also calculated a five-dimensional dipole moment surface (DMS) based on DFT(PBE0)/cc-pVTZ calculations. The HF and C60 molecules are considered rigid with bond length rHF = 0.9255 Å (gas phase ground rovibrational state geometry). The C60 geometry is of Ih symmetry. The ab initio points were fitted to obtain a PES in terms of bipolar spherical harmonics. The minimum of the PES corresponds to a geometry where the center of mass of HF is located 0.11 Å away from the center of the cage with an interaction energy of -6.929 kcal/mol. The DMS was also represented in terms of bipolar spherical harmonics. The PES was used to calculate the rotation-translation bound states of HF@C60, and good agreement was found relative to the available experimental data [A. Krachmalnicoff et al., Nat. Chem. 8, 953 (2016)] except for the splitting of the first rotational excitation levels. We propose an empirical adjustment to the PES in order to account for the experimentally observed symmetry breaking. The form of that effective PES is additive. We also propose an effective Hamiltonian with an adjusted rotational constant in order to quantitatively reproduce the experimental results including the splitting of the first rotational state. We use our models to compute the molecular volume polarizability of HF confined by C60 and obtain good agreement with experiment.

Potential energy and dipole moment surfaces for HF@C60: Prediction of spectral and electric response properties.

PubMed

Kalugina, Yulia N; Roy, Pierre-Nicholas

2017-12-28

We present a five-dimensional potential energy surface (PES) for the HF@C 60 system computed at the DF-LMP2/cc-pVTZ level of theory. We also calculated a five-dimensional dipole moment surface (DMS) based on DFT(PBE0)/cc-pVTZ calculations. The HF and C 60 molecules are considered rigid with bond length r HF = 0.9255 Å (gas phase ground rovibrational state geometry). The C 60 geometry is of I h symmetry. The ab initio points were fitted to obtain a PES in terms of bipolar spherical harmonics. The minimum of the PES corresponds to a geometry where the center of mass of HF is located 0.11 Å away from the center of the cage with an interaction energy of -6.929 kcal/mol. The DMS was also represented in terms of bipolar spherical harmonics. The PES was used to calculate the rotation-translation bound states of HF@C 60 , and good agreement was found relative to the available experimental data [A. Krachmalnicoff et al., Nat. Chem. 8, 953 (2016)] except for the splitting of the first rotational excitation levels. We propose an empirical adjustment to the PES in order to account for the experimentally observed symmetry breaking. The form of that effective PES is additive. We also propose an effective Hamiltonian with an adjusted rotational constant in order to quantitatively reproduce the experimental results including the splitting of the first rotational state. We use our models to compute the molecular volume polarizability of HF confined by C 60 and obtain good agreement with experiment.

Development and fabrication of an autoclave molded PES/Quartz sandwich radome

NASA Astrophysics Data System (ADS)

Stanton, Leonard E.; Levin, Stephen D.

1993-04-01

A cohesively bonded, thermoplastic composite sandwich radome for a leading edge supersonic aircraft has been built using autoclave processing with PES/Quartz prepreg and a PES coated honeycomb core. Processes were developed for solvent removal, thermoplastic laminate consolidation, surface etching to improve adhesion, honeycomb coating and forming, and ultrasound testing of bond integrity. Environmental testing was also conducted to verify the structural integrity of the radome for its intended application.

Structural and Thermodynamic Properties of the Argon Dimer: A Computational Chemistry Exercise in Quantum and Statistical Mechanics

ERIC Educational Resources Information Center

Halpern, Arthur M.

2010-01-01

Using readily available computational applications and resources, students can construct a high-level ab initio potential energy surface (PES) for the argon dimer. From this information, they can obtain detailed molecular constants of the dimer, including its dissociation energy, which compare well with experimental determinations. Using both…

Fabrication and Synthesis of Highly Ordered Nickel Cobalt Sulfide Nanowire-Grown Woven Kevlar Fiber/Reduced Graphene Oxide/Polyester Composites.

PubMed

Hazarika, Ankita; Deka, Biplab K; Kim, DoYoung; Roh, Hyung Doh; Park, Young-Bin; Park, Hyung Wook

2017-10-18

Well-aligned NiCo 2 S 4 nanowires, synthesized hydrothermally on the surface of woven Kevlar fiber (WKF), were used to fabricate composites with reduced graphene oxide (rGO) dispersed in polyester resin (PES) by means of vacuum-assisted resin transfer molding. The NiCo 2 S 4 nanowires were synthesized with three precursor concentrations. Nanowire growth was characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Hierarchical and high growth density of the nanowires led to exceptional mechanical properties of the composites. Compared with bare WKF/PES, the tensile strength and absorbed impact energy were enhanced by 96.2% and 92.3%, respectively, for WKF/NiCo 2 S 4 /rGO (1.5%)/PES. The synergistic effect of NiCo 2 S 4 nanowires and rGO in the fabricated composites improved the electrical conductivity of insulating WKF/PES composites, reducing the resistance to ∼10 3 Ω. Joule heating performance depended strongly on the precursor concentration of the nanowires and the presence of rGO in the composite. A maximum surface temperature of 163 °C was obtained under low-voltage (5 V) application. The Joule heating performance of the composites was demonstrated in a surface deicing experiment; we observed that 17 g of ice melted from the surface of the composite in 14 min under an applied voltage of 5 V at -28 °C. The excellent performance of WKF/NiCo 2 S 4 /rGO/PES composites shows great potential for aerospace structural applications requiring outstanding mechanical properties and Joule heating capability for deicing of surfaces.

Vibrational energies for HFCO using a neural network sum of exponentials potential energy surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pradhan, Ekadashi; Brown, Alex, E-mail: alex.brown@ualberta.ca

2016-05-07

A six-dimensional potential energy surface (PES) for formyl fluoride (HFCO) is fit in a sum-of-products form using neural network exponential fitting functions. The ab initio data upon which the fit is based were computed at the explicitly correlated coupled cluster with single, double, and perturbative triple excitations [CCSD(T)-F12]/cc-pVTZ-F12 level of theory. The PES fit is accurate (RMSE = 10 cm{sup −1}) up to 10 000 cm{sup −1} above the zero point energy and covers most of the experimentally measured IR data. The PES is validated by computing vibrational energies for both HFCO and deuterated formyl fluoride (DFCO) using block improved relaxationmore » with the multi-configuration time dependent Hartree approach. The frequencies of the fundamental modes, and all other vibrational states up to 5000 cm{sup −1} above the zero-point energy, are more accurate than those obtained from the previous MP2-based PES. The vibrational frequencies obtained on the PES are compared to anharmonic frequencies at the MP2/aug-cc-pVTZ and CCSD(T)/aug-cc-pVTZ levels of theory obtained using second-order vibrational perturbation theory. The new PES will be useful for quantum dynamics simulations for both HFCO and DFCO, e.g., studies of intramolecular vibrational redistribution leading to unimolecular dissociation and its laser control.« less

Direct Quantum Dynamics Using Grid-Based Wave Function Propagation and Machine-Learned Potential Energy Surfaces.

PubMed

Richings, Gareth W; Habershon, Scott

2017-09-12

We describe a method for performing nuclear quantum dynamics calculations using standard, grid-based algorithms, including the multiconfiguration time-dependent Hartree (MCTDH) method, where the potential energy surface (PES) is calculated "on-the-fly". The method of Gaussian process regression (GPR) is used to construct a global representation of the PES using values of the energy at points distributed in molecular configuration space during the course of the wavepacket propagation. We demonstrate this direct dynamics approach for both an analytical PES function describing 3-dimensional proton transfer dynamics in malonaldehyde and for 2- and 6-dimensional quantum dynamics simulations of proton transfer in salicylaldimine. In the case of salicylaldimine we also perform calculations in which the PES is constructed using Hartree-Fock calculations through an interface to an ab initio electronic structure code. In all cases, the results of the quantum dynamics simulations are in excellent agreement with previous simulations of both systems yet do not require prior fitting of a PES at any stage. Our approach (implemented in a development version of the Quantics package) opens a route to performing accurate quantum dynamics simulations via wave function propagation of many-dimensional molecular systems in a direct and efficient manner.

Hemocompatible polyethersulfone/polyurethane composite membrane for high-performance antifouling and antithrombotic dialyzer.

PubMed

Yin, Zehua; Cheng, Chong; Qin, Hui; Nie, Chuanxiong; He, Chao; Zhao, Changsheng

2015-01-01

Researches on blood purification membranes are fuelled by diverse clinical needs, such as hemodialysis, hemodiafiltration, hemofiltration, plasmapheresis, and plasma collection. To approach high-performance dialyzer, the integrated antifouling and antithrombotic properties are highly necessary for the design/modification of advanced artificial membranes. In this study, we propose and demonstrate that the physical blend of triblock polyurethane (PU) and polyethersulfone (PES) may advance the performance of hemodialysis membranes with greatly enhanced blood compatibility. It was found that the triblock PU could be blended with PES at high ratio owing to their excellent miscibility. The surfaces of the PES/PU composite membranes were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, water contact angle measurement, and surface ζ-potentials. The results indicated that the membrane surfaces were assembled with hydrophilic segregation layer owing to the migration of amphiphilic PU segments during membrane preparation, which might confer the composite membranes with superior hemocompatibility. The cross-section scanning electron microscopy images of the composite membranes exhibited structure transformation from finger-like structure to sponge-like structure, which indicated that the composite membrane had tunable porosity and permeability. The further ultrafiltration experiments indicated that the composite membranes showed increased permeability and excellent antifouling ability. The blood compatibility observation indicated that PES/PU composite membranes owned decreased protein adsorption, suppressed platelet adhesion, and prolonged plasma recalcification time. These results indicated that the PES/PU composite membranes exhibited enhanced antifouling and antithrombotic properties than the pristine PES membrane. The strategy may forward the fabrication of blood compatible composite membranes for clinical blood dialysis by using the various functional miscible polymers. © 2014 Wiley Periodicals, Inc.

A nonribosomal peptide synthetase (Pes1) confers protection against oxidative stress in Aspergillus fumigatus.

PubMed

Reeves, Emer P; Reiber, Kathrin; Neville, Claire; Scheibner, Olaf; Kavanagh, Kevin; Doyle, Sean

2006-07-01

Aspergillus fumigatus is an important human fungal pathogen. The Aspergillus fumigatus genome contains 14 nonribosomal peptide synthetase genes, potentially responsible for generating metabolites that contribute to organismal virulence. Differential expression of the nonribosomal peptide synthetase gene, pes1, in four strains of Aspergillus fumigatus was observed. The pattern of pes1 expression differed from that of a putative siderophore synthetase gene, sidD, and so is unlikely to be involved in iron acquisition. The Pes1 protein (expected molecular mass 698 kDa) was partially purified and identified by immunoreactivity, peptide mass fingerprinting (36% sequence coverage) and MALDI LIFT-TOF/TOF MS (four internal peptides sequenced). A pes1 disruption mutant (delta pes1) of Aspergillus fumigatus strain 293.1 was generated and confirmed by Southern and western analysis, in addition to RT-PCR. The delta pes1 mutant also showed significantly reduced virulence in the Galleria mellonella model system (P < 0.001) and increased sensitivity to oxidative stress (P = 0.002) in culture and during neutrophil-mediated phagocytosis. In addition, the mutant exhibited altered conidial surface morphology and hydrophilicity, compared to Aspergillus fumigatus 293.1. It is concluded that pes1 contributes to improved fungal tolerance against oxidative stress, mediated by the conidial phenotype, during the infection process.

A refined quartic potential energy surface and large scale vibrational calculations for S0 thiophosgene.

PubMed

Rashev, Svetoslav; Moule, David C

2015-04-05

In this work we present a full 6D quartic potential energy surface (PES) for S0 thiophosgene in curvilinear symmetrized bond-angle coordinates. The PES was refined starting from an ab initio field derived from acc-pVTZ basis set with CCSD(T) corrections for electron correlation. In the present calculations we used our variational method that was recently tested on formaldehyde and some of its isotopomers, along with additional improvements. The lower experimentally known vibrational levels for 35Cl2CS were reproduced quite well in the calculations, which can be regarded as a test for the feasibility of the obtained quartic PES. Copyright © 2015 Elsevier B.V. All rights reserved.

Interpolating moving least-squares methods for fitting potential energy surfaces: using classical trajectories to explore configuration space.

PubMed

Dawes, Richard; Passalacqua, Alessio; Wagner, Albert F; Sewell, Thomas D; Minkoff, Michael; Thompson, Donald L

2009-04-14

We develop two approaches for growing a fitted potential energy surface (PES) by the interpolating moving least-squares (IMLS) technique using classical trajectories. We illustrate both approaches by calculating nitrous acid (HONO) cis-->trans isomerization trajectories under the control of ab initio forces from low-level HF/cc-pVDZ electronic structure calculations. In this illustrative example, as few as 300 ab initio energy/gradient calculations are required to converge the isomerization rate constant at a fixed energy to approximately 10%. Neither approach requires any preliminary electronic structure calculations or initial approximate representation of the PES (beyond information required for trajectory initial conditions). Hessians are not required. Both approaches rely on the fitting error estimation properties of IMLS fits. The first approach, called IMLS-accelerated direct dynamics, propagates individual trajectories directly with no preliminary exploratory trajectories. The PES is grown "on the fly" with the computation of new ab initio data only when a fitting error estimate exceeds a prescribed tight tolerance. The second approach, called dynamics-driven IMLS fitting, uses relatively inexpensive exploratory trajectories to both determine and fit the dynamically accessible configuration space. Once exploratory trajectories no longer find configurations with fitting error estimates higher than the designated accuracy, the IMLS fit is considered to be complete and usable in classical trajectory calculations or other applications.

Sonoanatomic Variation of Pes Anserine Bursa

PubMed Central

Imani, Farnad; Abolhasan Gharehdag, Farid; Faiz, Seyed Hamid Reza

2013-01-01

Background The pes anserine bursa lies beneath the pes anserine tendon, which is the insertional tendon of the sartorius, gracilis, and semitendinosus muscles on the medial side of the tibia, but it can lie in different sites in the medial knee. Accurate diagnosis of the position of the bursa is critical for diagnostic and therapeutic goals. The aim of this study was to evaluate sonoanatomic variations of the pes anserine bursa in the medial knee. Methods One hundred seventy asymptomatic volunteers were enrolled in this study. Using ultrasound imaging (transverse approach, 7-13 MHz linear array probe) the sonoanatomic position of the pes anserine bursa and its relation to the pes anserine tendon were evaluated. Additionally, we evaluated the sonoanatomic variation of the saphenous nerve. Results The position of the pes anserine bursa was between the medial collateral ligament and the pes anserine tendons in 21.2%/18.8% (males/females) of subjects; between the pes anserine tendons and the tibia in 67.1%/64.7% (m/f); and among the pes anserine tendons in 8.2%/12.9% (m/f). No significant differences in the position of the bursa existed between males and females. The saphenous nerve was found within the pes anserine tendons in 77.6%/74.1% (m/f) of subjects, but outside the pes anserine tendons in 18.8%/15.3% (m/f). Visibility of sonoanatomic structures was not related to either gender or BMI. Conclusions Ultrasound provides very accurate information about variations in the pes anserine bursa and the saphenous nerve. This suggests that our proposed ultrasound method can be a reliable guide to facilitate approaches to the medial knee for diagnostic and therapeutic objectives. PMID:23861998

Zero-point energy conservation in classical trajectory simulations: Application to H2CO

NASA Astrophysics Data System (ADS)

Lee, Kin Long Kelvin; Quinn, Mitchell S.; Kolmann, Stephen J.; Kable, Scott H.; Jordan, Meredith J. T.

2018-05-01

A new approach for preventing zero-point energy (ZPE) violation in quasi-classical trajectory (QCT) simulations is presented and applied to H2CO "roaming" reactions. Zero-point energy may be problematic in roaming reactions because they occur at or near bond dissociation thresholds and these channels may be incorrectly open or closed depending on if, or how, ZPE has been treated. Here we run QCT simulations on a "ZPE-corrected" potential energy surface defined as the sum of the molecular potential energy surface (PES) and the global harmonic ZPE surface. Five different harmonic ZPE estimates are examined with four, on average, giving values within 4 kJ/mol—chemical accuracy—for H2CO. The local harmonic ZPE, at arbitrary molecular configurations, is subsequently defined in terms of "projected" Cartesian coordinates and a global ZPE "surface" is constructed using Shepard interpolation. This, combined with a second-order modified Shepard interpolated PES, V, allows us to construct a proof-of-concept ZPE-corrected PES for H2CO, Veff, at no additional computational cost to the PES itself. Both V and Veff are used to model product state distributions from the H + HCO → H2 + CO abstraction reaction, which are shown to reproduce the literature roaming product state distributions. Our ZPE-corrected PES allows all trajectories to be analysed, whereas, in previous simulations, a significant proportion was discarded because of ZPE violation. We find ZPE has little effect on product rotational distributions, validating previous QCT simulations. Running trajectories on V, however, shifts the product kinetic energy release to higher energy than on Veff and classical simulations of kinetic energy release should therefore be viewed with caution.

Treatment of laundry wastewater using polyethersulfone/polyvinylpyrollidone ultrafiltration membranes.

PubMed

Sumisha, A; Arthanareeswaran, G; Lukka Thuyavan, Y; Ismail, A F; Chakraborty, S

2015-11-01

In this study, laundry wastewater filtration was studied using hydrophilic polyvinylpyrollidone (PVP) modified polyethersulfone (PES) ultrafiltration membranes. The performances of PES/PVP membranes were assessed using commercial PES membrane with 10kDa in ultrafiltration. Operating parameters The influence of transmembrane pressure (TMP) and stirring speed on laundry wastewater flux was investigated. A higher permeate flux of 55.2L/m(2)h was obtained for modified PES membrane with high concentration of PVP at TMP of 500kPa and 750rpm of stirring speed. The separation efficiencies of membranes were also studied with respect to chemical oxygen demand (COD), total dissolved solids (TDS), turbidity and conductivity. Results showed that PES membrane with 10% of PVP had higher permeate flux, flux recovery and less fouling when compared with other membranes. Higher COD and TDS rejection of 88% and 82% were also observed for modified membranes due to the improved surface property of membranes. This indicated that modified PES membranes are suitable for the treatment of surfactant, detergent and oil from laundry wastewater. Copyright © 2015 Elsevier Inc. All rights reserved.

A Relation Between the Eikonal Equation Associated to a Potential Energy Surface and a Hyperbolic Wave Equation.

PubMed

Bofill, Josep Maria; Quapp, Wolfgang; Caballero, Marc

2012-12-11

The potential energy surface (PES) of a molecule can be decomposed into equipotential hypersurfaces. We show in this article that the hypersurfaces are the wave fronts of a certain hyperbolic partial differential equation, a wave equation. It is connected with the gradient lines, or the steepest descent, or the steepest ascent lines of the PES. The energy seen as a reaction coordinate plays the central role in this treatment.

Formaldehyde roaming dynamics: Comparison of quasi-classical trajectory calculations and experiments.

PubMed

Houston, Paul L; Wang, Xiaohong; Ghosh, Aryya; Bowman, Joel M; Quinn, Mitchell S; Kable, Scott H

2017-07-07

The photodissociation dynamics of roaming in formaldehyde are studied by comparing quasi-classical trajectory calculations performed on a new potential energy surface (PES) to new and detailed experimental results detailing the CO + H 2 product state distributions and their correlations. The new PES proves to be a significant improvement over the past one, now more than a decade old. The new experiments probe both the CO and H 2 products of the formaldehyde dissociation. The experimental and trajectory data offer unprecedented detail about the correlations between internal states of the CO and H 2 dissociation products as well as information on how these distributions are different for the roaming and transition-state pathways. The data investigated include, for dissociation on the formaldehyde 2 1 4 3 band, (a) the speed distributions for individual vibrational/rotational states of the CO products, providing information about the correlated internal energy distributions of the H 2 product, and (b) the rotational and vibrational distributions for the CO and H 2 products as well as the contributions to each from both the transition state and roaming channels. The agreement between the trajectory and experimental data is quite satisfactory, although minor differences are noted. The general agreement provides support for future use of the experimental techniques and the new PES in understanding the dynamics of photodissociative processes.

Kinetics and dynamics of the C(3P) + H2O reaction on a full-dimensional accurate triplet state potential energy surface.

PubMed

Li, Jun; Xie, Changjian; Guo, Hua

2017-08-30

A full dimensional accurate potential energy surface (PES) for the C( 3 P) and H 2 O reaction is developed based on ∼34 000 data points calculated at the level of the explicitly correlated unrestricted coupled cluster method with single, double, and perturbative triple excitations with the augmented correlation-consistent polarized triple zeta basis set (CCSD(T)-F12a/AVTZ). The PES is invariant with respect to the permutation of the two hydrogen atoms and the total root mean square error (RMSE) of the fit is only 0.31 kcal mol -1 . The PES features two barriers in the entrance channel and several potential minima, as well as multiple product channels. The rate coefficients of this reaction calculated using a transition-state theory and quasi-classical trajectory (QCT) method are small near room temperature, consistent with experiments. The reaction dynamics is also investigated with QCT on the new PES, which found that the reactivity is constrained by the entrance barriers and the final product branching is not statistical.

Communication: An accurate global potential energy surface for the ground electronic state of ozone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dawes, Richard, E-mail: dawesr@mst.edu, E-mail: hguo@unm.edu; Lolur, Phalgun; Li, Anyang

We report a new full-dimensional and global potential energy surface (PES) for the O + O{sub 2} → O{sub 3} ozone forming reaction based on explicitly correlated multireference configuration interaction (MRCI-F12) data. It extends our previous [R. Dawes, P. Lolur, J. Ma, and H. Guo, J. Chem. Phys. 135, 081102 (2011)] dynamically weighted multistate MRCI calculations of the asymptotic region which showed the widely found submerged reef along the minimum energy path to be the spurious result of an avoided crossing with an excited state. A spin-orbit correction was added and the PES tends asymptotically to the recently developed long-rangemore » electrostatic model of Lepers et al. [J. Chem. Phys. 137, 234305 (2012)]. This PES features: (1) excellent equilibrium structural parameters, (2) good agreement with experimental vibrational levels, (3) accurate dissociation energy, and (4) most-notably, a transition region without a spurious reef. The new PES is expected to allow insight into the still unresolved issues surrounding the kinetics, dynamics, and isotope signature of ozone.« less

Can conservation contracts co-exist with change? Payment for ecosystem services in the context of adaptive decision-making and sustainability.

PubMed

Hayes, Tanya; Murtinho, Felipe; Cárdenas Camacho, Luis Mario; Crespo, Patricio; McHugh, Sarah; Salmerón, David

2015-01-01

This paper considers the ability of payment for ecosystem services (PES) programs to operate in the context of dynamic and complex social-ecological systems. Drawing on the experiences of two different PES programs in Latin America, we examine how PES institutions fit with the tenets of adaptive decision-making for sustainable resource management. We identify how the program goals and the connection to the market influence the incentive structure, information gathering, learning and feedback processes, and the structure of decision-making rights, specifically the ability to make and modify resource-use rules. Although limited in their generalizability, findings from the two case studies suggest a tension between the contractual model of PES and adaptive decision-making in natural resource systems. PES programs are not inherently decentralized, flexible management tools, as PES contracts tend to restrict decision-making rights and offer minimal flexibility mechanisms to change resource-use practices over the duration of the contract period. Furthermore, PES design and flexibility is heavily dependent on the goals and mission of the buyer and the respective market. If PES is to facilitate sustainable resource management, greater attention is needed to assess how the institutional design of the PES contracts influence the motivation and capacity of participants and program officers alike to adaptively manage the respective resource systems.

Can Conservation Contracts Co-exist with Change? Payment for Ecosystem Services in the Context of Adaptive Decision-Making and Sustainability

NASA Astrophysics Data System (ADS)

Hayes, Tanya; Murtinho, Felipe; Cárdenas Camacho, Luis Mario; Crespo, Patricio; McHugh, Sarah; Salmerón, David

2015-01-01

This paper considers the ability of payment for ecosystem services (PES) programs to operate in the context of dynamic and complex social-ecological systems. Drawing on the experiences of two different PES programs in Latin America, we examine how PES institutions fit with the tenets of adaptive decision-making for sustainable resource management. We identify how the program goals and the connection to the market influence the incentive structure, information gathering, learning and feedback processes, and the structure of decision-making rights, specifically the ability to make and modify resource-use rules. Although limited in their generalizability, findings from the two case studies suggest a tension between the contractual model of PES and adaptive decision-making in natural resource systems. PES programs are not inherently decentralized, flexible management tools, as PES contracts tend to restrict decision-making rights and offer minimal flexibility mechanisms to change resource-use practices over the duration of the contract period. Furthermore, PES design and flexibility is heavily dependent on the goals and mission of the buyer and the respective market. If PES is to facilitate sustainable resource management, greater attention is needed to assess how the institutional design of the PES contracts influence the motivation and capacity of participants and program officers alike to adaptively manage the respective resource systems.

Effect of Graphene Oxide (GO) on the Surface Morphology & Hydrophilicity of Polyethersulfone (PES)

NASA Astrophysics Data System (ADS)

Junaidi, N. F. D.; Khalil, N. A.; Jahari, A. F.; Shaari, N. Z. K.; Shahruddin, M. Z.; Alias, N. H.; Othman, N. H.

2018-05-01

Membrane has been widely used in water and wastewater treatment. One of the major issues related membrane separation is concentration polarization or fouling, which can lead to a decline of flux and premature failure of membrane. However, fouling can be controlled by modification of membrane properties such as morphology and hydrophilicity. In this work, a modification of polymeric membrane, polyethersulfone (PES) was carried out using graphene oxide in order to attain high antifouling characteristics. Graphene oxide (GO) was added at different compositions ranging from (0.1 wt%-1.0 wt%). GO was synthesized using modified Hummers’ method and characterized using XRD and FTIR prior to using it as additive for the PES membrane. The prepared PES-GO composite membranes were characterized using FTIR and SEM, Contact angle measurement and pure water flux test were then conducted to investigate the hydrophilicity of the PES-GO membranes. It was found that the additions of GO has significantly improved the hydrophilicity of the membranes.

Methane dissociation on Ni(111): A fifteen-dimensional potential energy surface using neural network method

NASA Astrophysics Data System (ADS)

Shen, Xiangjian; Chen, Jun; Zhang, Zhaojun; Shao, Kejie; Zhang, Dong H.

2015-10-01

In the present work, we develop a highly accurate, fifteen-dimensional potential energy surface (PES) of CH4 interacting on a rigid flat Ni(111) surface with the methodology of neural network (NN) fit to a database consisted of about 194 208 ab initio density functional theory (DFT) energy points. Some careful tests of the accuracy of the fitting PES are given through the descriptions of the fitting quality, vibrational spectrum of CH4 in vacuum, transition state (TS) geometries as well as the activation barriers. Using a 25-60-60-1 NN structure, we obtain one of the best PESs with the least root mean square errors: 10.11 meV for the entrance region and 17.00 meV for the interaction and product regions. Our PES can reproduce the DFT results very well in particular for the important TS structures. Furthermore, we present the sticking probability S0 of ground state CH4 at the experimental surface temperature using some sudden approximations by Jackson's group. An in-depth explanation is given for the underestimated sticking probability.

A highly accurate ab initio potential energy surface for methane.

PubMed

Owens, Alec; Yurchenko, Sergei N; Yachmenev, Andrey; Tennyson, Jonathan; Thiel, Walter

2016-09-14

A new nine-dimensional potential energy surface (PES) for methane has been generated using state-of-the-art ab initio theory. The PES is based on explicitly correlated coupled cluster calculations with extrapolation to the complete basis set limit and incorporates a range of higher-level additive energy corrections. These include core-valence electron correlation, higher-order coupled cluster terms beyond perturbative triples, scalar relativistic effects, and the diagonal Born-Oppenheimer correction. Sub-wavenumber accuracy is achieved for the majority of experimentally known vibrational energy levels with the four fundamentals of (12)CH4 reproduced with a root-mean-square error of 0.70 cm(-1). The computed ab initio equilibrium C-H bond length is in excellent agreement with previous values despite pure rotational energies displaying minor systematic errors as J (rotational excitation) increases. It is shown that these errors can be significantly reduced by adjusting the equilibrium geometry. The PES represents the most accurate ab initio surface to date and will serve as a good starting point for empirical refinement.

Surface modification of ultra thin PES-zeolite using thermal annealing to increase flux and rejection of produced water treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusworo, T. D., E-mail: tdkusworo@che.undip.ac.id; Widayat,; Pradini, A. W.

2015-12-29

Membrane technology is an alternative of water treatment based on filtration that is being developed. Surface Modification using heat treatment has been investigated to improve the performance of ultra thin PES-Zeolite nanocomposite membrane for produced water treatment from Pertamina Balongan. Two types of membranes with surface modification and without modification were prepared to study the effect of surface modification on its permeation properties. Asymmetric ultra thin PES-Zeolite nanocomposite membrane for produced water treatment was casted using the dry/wet phase inversion technique from dope solutions containing polyethersulfone, N-methyl-2-pyrrolidone (NMP) as a solvent and zeolite as a filler. Experimental results showed thatmore » the heat treatment at near glass transition temperature was increase the rejection of COD, Turbidity and ion Ca{sup 2+}. The better adherence of zeolite particles in the polymer matrix combined with formation of charge transfer complexes (CTCs) and cross-linking might be the main factors to enhance the percent of rejection. Field emission scanning electron microscopy (FESEM) micrographs showed that the selective layer and the substructure of PES-zeolite membrane became denser and more compact after the heat treatment. The FESEM micrographs also showed that the heat treatment was increased the adherence of zeolite particle and polymer. Membranes treated at 180 °C for 15 seconds indicated increase the rejection and small decrease in flux for produced water treatment.« less

Integrated Modeling Approach for Verifying Water Storage Services for a Payment for Environmental Service Programs

NASA Astrophysics Data System (ADS)

Hendricks, G.; Shukla, S.; Guzha, A. C.

2013-12-01

Hydrologic models have been used for improved understanding of how an ecosystem's hydrologic response to human intervention and may provide substantial insight into the viability of payment for environmental services (PES) programs. Little is currently known about how hydrologic models can contribute to the design and evaluation of PES programs. Increased water storage is a desired environmental service (ES) for the Florida Everglades' watershed to reduce nutrient loads and excessive flows to lakes and estuaries in the region. We present monitoring and modeling results to verify the water storage PES for two ranch sites (wetland and watershed scales) located in the Northern Everglades region located north of the Lake Okeechobee (LO). Verification of the water storage PES using at least 3 years of hydrologic data was inconclusive due to variable rainfall during pre- and post-PES periods. An integrated surface and groundwater model, MIKE-SHE/MIKE11, was used to help verify the water storage service as well as predict ecological responses for different water storage scenarios (different levels of storage). The hydrological model was calibrated and validated using field measurements and was able to effectively simulate the surface and groundwater levels for the watershed (Nash Sutcliffe Efficiency, NSE = 0.54 to 0.82) and for surface water levels within wetlands (NSE = 0.54 to 0.84). Scenario analyses for storage levels showed an inverse relationship between board heights for water control structures and flows at the watershed outlet. Changes in flow were marginal when board heights approached a maximum indicating movement of water into subsurface storage. Combining simulation results with field measurements showed reduced flows and increased subsurface storage (2 cm/yr.), a desired outcome for protecting LO and estuarine systems from excessive flows. Simulated wetland water levels were combined with LIDAR-based topography to predict inundation for wetlands at the two PES sites for exploring the addition of biodiversity related ES. Simulations showed that effects of increased storage on enhanced hydro-periods and biodiversity was limited to the wetlands close to the drainage ditches. Results for a variety of water management scenarios showed that modeling can be used as an effective tool for optimizing the ES for a desired PES scheme. Measured and predicted surface flows from watershed and wetland water levels for different scenarios are currently being combined with ecological measurements to develop hydro-ecological models that predict the effects of enhanced water storage on ecological diversity.

High-k 3D-barium titanate foam/phenolphthalein poly(ether sulfone)/cyanate ester composites with frequency-stable dielectric properties and extremely low dielectric loss under reduced concentration of ceramics

NASA Astrophysics Data System (ADS)

Zheng, Longhui; Yuan, Li; Guan, Qingbao; Liang, Guozheng; Gu, Aijuan

2018-01-01

Higher dielectric constant, lower dielectric loss and better frequency stability have been the developing trends for high dielectric constant (high-k) materials. Herein, new composites have been developed through building unique structure by using hyperbranched polysiloxane modified 3D-barium titanate foam (BTF) (BTF@HSi) as the functional fillers and phenolphthalein poly(ether sulfone) (cPES)/cyanate ester (CE) blend as the resin matrix. For BTF@HSi/cPES/CE composite with 34.1 vol% BTF, its dielectric constant at 100 Hz is as high as 162 and dielectric loss is only 0.007; moreover, the dielectric properties of BTF@HSi/cPES/CE composites exhibit excellent frequency stability. To reveal the mechanism behind these attractive performances of BTF@HSi/cPES/CE composites, three kinds of composites (BTF/CE, BTF/cPES/CE, BTF@HSi/CE) were prepared, their structure and integrated performances were intensively investigated and compared with those of BTF@HSi/cPES/CE composites. Results show that the surface modification of BTF is good for preparing composites with improved thermal stability; while introducing flexible cPES to CE is beneficial to fabricate composites with good quality through effectively blocking cracks caused by the stress concentration, and then endowing the composites with good dielectric properties at reduced concentration of ceramics.

A nitrogen-doped carbon nanotube enhanced polyethersulfone membrane system for water treatment

NASA Astrophysics Data System (ADS)

Phao, Neo; Nxumalo, Edward N.; Mamba, Bhekie B.; Mhlanga, Sabelo D.

Water quality in South Africa and around the world continues to deteriorate due to contamination by organic, inorganic and microbial substances. While many efforts have been done to address water quality problems, current drinking water treatment technologies remain costly and do not effectively remove pollutants to acceptable levels. In this work nitrogen doped carbon nanotubes/polyethersulfone (N-CNT/PES) blend membranes were synthesized via a modified phase inversion method and assessed for suitability in drinking water treatment. The N-CNTs with outer diameters of 30-45 nm and 3% N content were prepared using a conventional chemical vapour deposition method and functionalized by refluxing in HNO3. The confirmation and degree of functionalization with -OH and -COOH groups was determined using Fourier-transform infrared (FTIR) spectroscopy and zeta potential analysis. FTIR studies confirmed the successful incorporation of functionalized N-CNTs (N-CNTs) in the membrane matrix. Atomic force microscopy (AFM) analysis revealed that the addition of N-CNTs leads to reduced surface roughness, suggesting a good dispersion of the N-CNTs in the matrix. Permeability studies revealed that the addition of N-CNTs to the polyethersulfone (PES) solution increased the water flux of the blend membrane by up to 70%. N-CNT loadings of 0.04 wt% in the blend membranes gave low surface contact angle of 55° and high fluxes. In addition, inclusion of N-CNTs enhanced the mechanical properties of the N-CNT/PES blend membranes. The use of N-CNTs in mixed matrix PES membranes is reported for the first time here. The result already suggests superior compatibility of the N-CNTs with PES compared to undoped CNTs, due to the high surface reactivity of the N-CNTs.

Cold collisions of SH- with He: Potential energy surface and rate coefficients

NASA Astrophysics Data System (ADS)

Bop, C. T.; Trabelsi, T.; Hammami, K.; Mogren Al Mogren, M.; Lique, F.; Hochlaf, M.

2017-09-01

Collisional energy transfer under cold conditions is of great importance from the fundamental and applicative point of view. Here, we investigate low temperature collisions of the SH- anion with He. We have generated a three-dimensional potential energy surface (PES) for the SH-(X1Σ+)-He(1S) van der Waals complex. The ab initio multi-dimensional interaction PES was computed using the explicitly correlated coupled cluster approach with simple, double, and perturbative triple excitation in conjunction with the augmented-correlation consistent-polarized valence triple zeta Gaussian basis set. The PES presents two minima located at linear geometries. Then, the PES was averaged over the ground vibrational wave function of the SH- molecule and the resulting two-dimensional PES was incorporated into exact quantum mechanical close coupling calculations to study the collisional excitation of SH- by He. We have computed inelastic cross sections among the 11 first rotational levels of SH- for energies up to 2500 cm-1. (De-)excitation rate coefficients were deduced for temperatures ranging from 1 to 300 K by thermally averaging the cross sections. We also performed calculations using the new PES for a fixed internuclear SH- distance. Both sets of results were found to be in reasonable agreement despite differences existing at low temperatures confirming that accurate predictions require the consideration of all internal degrees of freedom in the case of molecular hydrides. The rate coefficients presented here may be useful in interpreting future experimental work on the SH- negative ion colliding with He as those recently done for the OH--He collisional system as well as for possible astrophysical applications in case SH- would be detected in the interstellar medium.

Characterization of a resorbable poly(ester urethane) with biodegradable hard segments.

PubMed

Dempsey, David K; Robinson, Jennifer L; Iyer, Ananth V; Parakka, James P; Bezwada, Rao S; Cosgriff-Hernandez, Elizabeth M

2014-01-01

The rapid growth of regenerative medicine and drug delivery fields has generated a strong need for improved polymeric materials that degrade at a controlled rate into safe, non-cytotoxic by-products. Polyurethane thermoplastic elastomers offer several advantages over other polymeric materials including tunable mechanical properties, excellent fatigue strength, and versatile processing. The variable segmental chemistry in developing resorbable polyurethanes also enables fine control over the degradation profile as well as the mechanical properties. Linear aliphatic isocyanates are most commonly used in biodegradable polyurethane formulations; however, these aliphatic polyurethanes do not match the mechanical properties of their aromatic counterparts. In this study, a novel poly(ester urethane) (PEsU) synthesized with biodegradable aromatic isocyanates based on glycolic acid was characterized for potential use as a new resorbable material in medical devices. Infrared spectral analysis confirmed the aromatic and phase-separated nature of the PEsU. Uniaxial tensile testing displayed stress-strain behavior typical of a semi-crystalline polymer above its Tg, in agreement with calorimetric findings. PEsU outperformed aliphatic PCL-based polyurethanes likely due to the enhanced cohesion of the aromatic hard domains. Accelerated degradation of the PEsU using 0.1 M sodium hydroxide resulted in hydrolysis of the polyester soft segment on the surface, reduced molecular weight, surface cracking, and a 30% mass loss after four weeks. Calorimetric studies indicated a disruption of the soft segment crystallinity after incubation which corresponded with a drop in initial modulus of the PEsU. Finally, cytocompatibility testing with 3T3 mouse fibroblasts exhibited cell viability on PEsU films comparable to a commercial poly(ether urethane urea) after 24 h followed by 85% cell viability at 72 h. Overall, this new resorbable polyurethane shows strong potential for use in wide range of biomedical applications.

Influence of Brij58 on the Characteristic and Performance of PES Membrane for Water Treatment Process

NASA Astrophysics Data System (ADS)

Mukramah; Syawaliah; Mulyati, S.; Arahman, N.

2017-03-01

This study proposes a modification of polyether sulfone (PES) membrane by blending the polymer with a hydrophilic additive of Brij-58. Flat-sheet PES membrane was prepared through a non-solvent induced phase separation (NIPS) method using dimethylformamide (DMF) as a solvent. PES membrane was modified by adding Brij-58 into dope solution at a different concentration, i.e 1, 3, 5, 7, and 10 wt %. The fabricated membranes were characterized by means of Scanning Electron Microscopy (SEM) and Fourier Transform Infra-Red (FTIR) spectroscopy. Filtration performance of membrane was analyzed by using a dead-end module. It is found that the addition of a small amount of Brij into polymer solution brought about the increase of water flux. FT-IR investigation showed that the additive exist on the surface of a blended membrane.

Exploring a potential energy surface by machine learning for characterizing atomic transport

NASA Astrophysics Data System (ADS)

Kanamori, Kenta; Toyoura, Kazuaki; Honda, Junya; Hattori, Kazuki; Seko, Atsuto; Karasuyama, Masayuki; Shitara, Kazuki; Shiga, Motoki; Kuwabara, Akihide; Takeuchi, Ichiro

2018-03-01

We propose a machine-learning method for evaluating the potential barrier governing atomic transport based on the preferential selection of dominant points for atomic transport. The proposed method generates numerous random samples of the entire potential energy surface (PES) from a probabilistic Gaussian process model of the PES, which enables defining the likelihood of the dominant points. The robustness and efficiency of the method are demonstrated on a dozen model cases for proton diffusion in oxides, in comparison with a conventional nudge elastic band method.

Many Experts, Many Audiences: Public Engagement with Science and Informal Science Education. A CAISE Inquiry Group Report. Executive Summary

ERIC Educational Resources Information Center

McCallie, Ellen; Bell, Larry; Lohwater, Tiffany; Falk, John H.; Lehr, Jane L.; Lewenstein, Bruce V.; Needham, Cynthia; Wiehe, Ben

2009-01-01

Science and technology are embedded in every aspect of modern life. This executive summary describes how Public Engagement with Science (PES), in the context of informal science education (ISE), can provide opportunities for public awareness of and participation in science and technology. PES is an approach that has developed in the last 10 years…

Plasma treatment of polyethersulfone membrane for benzene removal from water by air gap membrane distillation.

PubMed

Pedram, Sara; Mortaheb, Hamid Reza; Arefi-Khonsari, Farzaneh

2018-01-01

In order to obtain a durable cost-effective membrane for membrane distillation (MD) process, flat sheet polyethersulfone (PES) membranes were modified by an atmospheric pressure nonequilibrium plasma generated using a dielectric barrier discharge in a mixture of argon and hexamethyldisiloxane as the organosilicon precursor. The surface properties of the plasma-modified membranes were characterized by water contact angle (CA), liquid entry pressure, X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy. The water CA of the membrane was increased from 64° to 104° by depositing a Si(CH 3 )-rich thin layer. While the pristine PES membrane was not applicable in the MD process, the modified PES membrane could be applied for the first time in an air gap membrane distillation setup for the removal of benzene as a volatile organic compound from water. The experimental design using central composite design and response surface methodology was applied to study the effects of feed temperature, concentration, and flow rate as well as their binary interactions on the overall permeate flux and separation factor. The separation factor and permeation flux of the modified PES membrane at optimum conditions were comparable with those of commercial polytetrafluoroethylene membrane.

Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

NASA Astrophysics Data System (ADS)

Han, Huixian; Li, Anyang; Guo, Hua

2014-12-01

A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S0) electronic state has been constructed by fitting ˜37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm-1. The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm-1 above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction.

A generalized force-modified potential energy surface (G-FMPES) for mechanochemical simulations

DOE PAGES

Subramanian, Gopinath; Mathew, Nithin; Leiding, Jeffery A.

2015-10-05

We describe the modifications that a spatially varying external load produces on a Born-Oppenheimer potential energy surface (PES) by calculating static quantities of interest. The effects of the external loads are exemplified using electronic structure calculations (at the HF/6-31G** level) of two different molecules: ethane and hexahydro-1,3,5-trinitro-s-triazine (RDX). The calculated transition states and The Hessian matrices of stationary points show that spatially varying external loads shift the stationary points and modify the curvature of the PES, thereby affecting the harmonic transition rates by altering both the energy barrier as well as the prefactor. The harmonic spectra of both molecules aremore » blue-shifted with increasing compressive “pressure.” Some stationary points on the RDX-PES disappear under application of the external load, indicating the merging of an energy minimum with a saddle point.« less

A new global analytical potential energy surface of NaH2+ system and dynamical calculation for H(2S) + NaH+(X2Σ+) → Na+(1S) + H2(X1Σg+) reaction

NASA Astrophysics Data System (ADS)

Yuan, Meiling; Li, Wentao; Yuan, Jiuchuang

2018-05-01

A new global potential energy surface (PES) of the NaH2+ system is constructed by fitting 27,621 ab initio energy points with the neural network method. The root mean square error of the new PES is only 4.1609 × 10-4 eV. Based on the new PES, dynamical calculations have been performed using the time-dependent quantum wave packet method. These results are then compared with the H(2S) + LiH+(X2Σ+) → Li+(1S) + H2(X1Σg+) reaction. The direct abstract mechanism is found to play an important role in the reaction because only forward scattering signals on the differential cross section results for all calculated collision energies.

78 FR 34708 - Proposed Information Collection (Foot (Including Flatfeet (pes planus)) Conditions Disability...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-10

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Characterization of Surface Modification of Polyethersulfone Membrane

USDA-ARS?s Scientific Manuscript database

Surface modification of polyethersulfone (PES) membrane surface using UV/ozone-treated grafting and interfacial polymerization on membrane surface was investigated in order to improve the resistance of membrane surface to protein adsorption. These methods of surface modification were compared in te...

The OH + D2 --> HOD + D angle-velocity distribution: quasi-classical trajectory calculations on the YZCL2 and WSLFH potential energy surfaces and comparison with experiments at ET = 0.28 eV.

PubMed

Sierra, José Daniel; Martínez, Rodrigo; Hernando, Jordi; González, Miguel

2009-12-28

The angle-velocity distribution (HOD) of the OH + D(2) reaction at a relative translational energy of 0.28 eV has been calculated using the quasi-classical trajectory (QCT) method on the two most recent potential energy surfaces available (YZCL2 and WSLFH PESs), widely extending a previous investigation of our group. Comparison with the high resolution experiments of Davis and co-workers (Science, 2000, 290, 958) shows that the structures (peaks) found in the relative translational energy distributions of products could not be satisfactorily reproduced in the calculations, probably due to the classical nature of the QCT method and the importance of quantum effects. The calculations, however, worked quite well for other properties. Overall, both surfaces led to similar results, although the YZCL2 surface is more accurate to describe the H(3)O PES, as derived from comparison with high level ab initio results. The differences observed in the QCT calculations were interpreted considering the somewhat larger anisotropy of the YZCL2 PES when compared with the WSLFH PES.

Fouling potential evaluation of soluble microbial products (SMP) with different membrane surfaces in a hybrid membrane bioreactor using worm reactor for sludge reduction.

PubMed

Li, Zhipeng; Tian, Yu; Ding, Yi; Chen, Lin; Wang, Haoyu

2013-07-01

The fouling characteristics of soluble microbial products (SMP) in the membrane bioreactor coupled with Static Sequencing Batch Worm Reactor (SSBWR-MBR) were tested with different types of membranes. It was noted that the flux decrements of S-SMP (SMP in SSBWR-MBR) with cellulose acetate (CA), polyvinylidene fluoride (PVDF) and polyether sulfones (PES) membranes were respectively 6.7%, 8.5% and 9.5% lower compared to those of C-SMP (SMP in Control-MBR) with corresponding membranes. However, for both the filtration of the C-SMP and S-SMP, the CA membrane exhibited the fastest diminishing rate of flux among the three types of membranes. The surface morphology analysis showed that the CA membrane exhibited more but smaller protuberances compared to the PVDF and PES. The second minimums surrounding each protruding asperity on CA membrane were more than those on the PVDF and PES membranes, enhancing the attachment of SMP onto the membrane surface. Copyright © 2013 Elsevier Ltd. All rights reserved.

Accelerated path-integral simulations using ring-polymer interpolation

NASA Astrophysics Data System (ADS)

Buxton, Samuel J.; Habershon, Scott

2017-12-01

Imaginary-time path-integral (PI) molecular simulations can be used to calculate exact quantum statistical mechanical properties for complex systems containing many interacting atoms and molecules. The limiting computational factor in a PI simulation is typically the evaluation of the potential energy surface (PES) and forces at each ring-polymer "bead"; for an n-bead ring-polymer, a PI simulation is typically n times greater than the corresponding classical simulation. To address the increased computational effort of PI simulations, several approaches have been developed recently, most notably based on the idea of ring-polymer contraction which exploits either the separation of the PES into short-range and long-range contributions or the availability of a computationally inexpensive PES which can be incorporated to effectively smooth the ring-polymer PES; neither approach is satisfactory in applications to systems modeled by PESs given by on-the-fly ab initio calculations. In this article, we describe a new method, ring-polymer interpolation (RPI), which can be used to accelerate PI simulations without any prior assumptions about the PES. In simulations of liquid water modeled by an empirical PES (or force field) under ambient conditions, where quantum effects are known to play a subtle role in influencing experimental observables such as radial distribution functions, we find that RPI can accurately reproduce the results of fully-converged PI simulations, albeit with far fewer PES evaluations. This approach therefore opens the possibility of large-scale PI simulations using ab initio PESs evaluated on-the-fly without the drawbacks of current methods.

The Electronic Structure of the Cs/ n-GaN(0001) Nano-Interface

NASA Astrophysics Data System (ADS)

Benemanskaya, G. V.; Lapushkin, M. N.; Marchenko, D. E.; Timoshnev, S. N.

2018-03-01

Electronic structures of the n-GaN(0001) surface and Cs/ n-GaN(0001) interface with submonolayer Cs coverages were studied for the first time in situ by the photoelectron spectroscopy (PES) method. The spectra of photoemission from the valence band, surface electron states, and core levels (Ga 3 d, Cs 4 d, Cs 5 p) under synchrotron excitation were measured in a range of photon energies within 50-150 eV. Evolution of the spectrum of surface states near the valence-band maximum was revealed by PES during the adsorption of Cs atoms. A metallic character of the Cs/ n-GaN(0001) nano-interface is demonstrated.

Phenyl radical + propene: a prototypical reaction surface for aromatic-catalyzed 1,2-hydrogen-migration and subsequent resonance-stabilized radical formation.

PubMed

Buras, Zachary J; Chu, Te-Chun; Jamal, Adeel; Yee, Nathan W; Middaugh, Joshua E; Green, William H

2018-05-16

The C9H11 potential energy surface (PES) was experimentally and theoretically explored because it is a relatively simple, prototypical alkylaromatic radical system. Although the C9H11 PES has already been extensively studied both experimentally (under single-collision and thermal conditions) and theoretically, new insights were made in this work by taking a new experimental approach: flash photolysis combined with time-resolved molecular beam mass spectrometry (MBMS) and visible laser absorbance. The C9H11 PES was experimentally accessed by photolytic generation of the phenyl radical and subsequent reaction with excess propene (C6H5 + C3H6). The overall kinetics of C6H5 + C3H6 was measured using laser absorbance with high time-resolution from 300 to 700 K and was found to be in agreement with earlier measurements over a lower temperature range. Five major product channels of C6H5 + C3H6 were observed with MBMS at 600 and 700 K, four of which were expected: hydrogen (H)-abstraction (measured by the stable benzene, C6H6, product), methyl radical (CH3)-loss (styrene detected), H-loss (phenylpropene isomers detected) and radical adduct stabilization. The fifth, unexpected product observed was the benzyl radical, which was rationalized by the inclusion of a previously unreported pathway on the C9H11 PES: aromatic-catalysed 1,2-H-migration and subsequent resonance stabilized radical (RSR, benzyl radical in this case) formation. The current theoretical understanding of the C9H11 PES was supported (including the aromatic-catalyzed pathway) by quantitative comparisons between modelled and experimental MBMS results. At 700 K, the branching to styrene + CH3 was 2-4 times greater than that of any other product channel, while benzyl radical + C2H4 from the aromatic-catalyzed pathway accounted for ∼10% of the branching. Single-collision conditions were also simulated on the updated PES to explain why previous crossed molecular beam experiments did not see evidence of the aromatic-catalyzed pathway. This experimentally validated knowledge of the C9H11 PES was added to the database of the open-source Reaction Mechanism Generator (RMG), which was then used to generalize the findings on the C9H11 PES to a slightly more complicated alkylaromatic system.

New more accurate calculations of the ground state potential energy surface of H(3) (+).

PubMed

Pavanello, Michele; Tung, Wei-Cheng; Leonarski, Filip; Adamowicz, Ludwik

2009-02-21

Explicitly correlated Gaussian functions with floating centers have been employed to recalculate the ground state potential energy surface (PES) of the H(3) (+) ion with much higher accuracy than it was done before. The nonlinear parameters of the Gaussians (i.e., the exponents and the centers) have been variationally optimized with a procedure employing the analytical gradient of the energy with respect to these parameters. The basis sets for calculating new PES points were guessed from the points already calculated. This allowed us to considerably speed up the calculations and achieve very high accuracy of the results.

HEMORHEOLOGICAL IMPLICATIONS OF PERFLUOROCARBON BASED OXYGEN CARRIER INTERACTION WITH COLLOID PLASMA EXPANDERS AND BLOOD

PubMed Central

Vásquez, Diana M.; Ortiz, Daniel; Alvarez, Oscar A.; Briceño, Juan C.; Cabrales, Pedro

2013-01-01

Perfluorocarbon (PFC) emulsion based oxygen carriers lack colloid osmotic pressure (COP) and must be administered with colloid-based plasma expanders (PEs). Although PFC emulsions have been widely studied, there is limited information about PFC emulsion interaction with PEs and blood. Their interaction forms aggregates due to electrostatic and rheological phenomena, and change blood rheology and blood flow. This study analyzes the effects of the interaction between PFC emulsions with blood in the presence of clinically-used PEs. The rheological behavior of the mixtures was analyzed in parallel with in vivo analysis of blood flow in microvessels using intravital microscopy when administered in a clinically relevant scenario. The interaction between the PFC emulsion and PE with blood produced PFC droplets and red blood cell (RBCs) aggregation, and increased blood viscosity. The PFC droplets formed aggregates when mixed with PEs containing electrolytes, and the aggregation increased with the electrolyte concentration. Mixtures of PFC with PEs that produced PFC aggregates also induced RCBs aggregation when mixed with blood, increasing blood viscosity at low shear rates. The more viscous suspension at low shear rates produced a blunted blood flow velocity profile in vivo relative to non-aggregating mixtures of PFC and PEs. For the PEs evaluated, albumin produced minimal to undetectable aggregation. PFC and PEs interaction with blood can affect sections of the microcirculation with low shear rate (e.g. arterioles, venules, and pulmonary circulation) because aggregates could cause capillary occlusion, decrease perfusion, pulmonary emboli, or focal ischemia. PMID:23606592

Hydrophilic modification of polyethersulfone and its membrane characteristics

NASA Astrophysics Data System (ADS)

Liu, Haiju; Huangfu, Feng-yun; Bai, Yundong; Kong, Yuanyuan

2010-07-01

In order to enhance the hydrophilicity of PES, A series of sulfonated polyethersulfone (SPES) were readily prepared via a reaction of sulphonation which used chlorosulfonic as sulfonating agent and concentrated sulfuric acid as solvent. Sulfonation was confirmed by Fourier transform infrared spectroscopy and Thermo gravimetric analyzer. We studied forming film characteristic of SPES by phase diagram. The sulfonated PES materials were then utilized as a hydrophilic modifier for fabrication of SPES membranes. The solvent was NMP and PEG-6000 was pore-forming agent. The characteristics of membranes were studied. It was found that the surface hydrophilicity of the modified PES membranes was remarkably enhanced by contact angle. Water flux was obvious increased and antifouling performance was also improved.

Low-rank canonical-tensor decomposition of potential energy surfaces: application to grid-based diagrammatic vibrational Green's function theory

NASA Astrophysics Data System (ADS)

Rai, Prashant; Sargsyan, Khachik; Najm, Habib; Hermes, Matthew R.; Hirata, So

2017-09-01

A new method is proposed for a fast evaluation of high-dimensional integrals of potential energy surfaces (PES) that arise in many areas of quantum dynamics. It decomposes a PES into a canonical low-rank tensor format, reducing its integral into a relatively short sum of products of low-dimensional integrals. The decomposition is achieved by the alternating least squares (ALS) algorithm, requiring only a small number of single-point energy evaluations. Therefore, it eradicates a force-constant evaluation as the hotspot of many quantum dynamics simulations and also possibly lifts the curse of dimensionality. This general method is applied to the anharmonic vibrational zero-point and transition energy calculations of molecules using the second-order diagrammatic vibrational many-body Green's function (XVH2) theory with a harmonic-approximation reference. In this application, high dimensional PES and Green's functions are both subjected to a low-rank decomposition. Evaluating the molecular integrals over a low-rank PES and Green's functions as sums of low-dimensional integrals using the Gauss-Hermite quadrature, this canonical-tensor-decomposition-based XVH2 (CT-XVH2) achieves an accuracy of 0.1 cm-1 or higher and nearly an order of magnitude speedup as compared with the original algorithm using force constants for water and formaldehyde.

Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Huixian; School of Physics, Northwest University, Xi’an, Shaanxi 710069; Li, Anyang

2014-12-28

A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S{sub 0}) electronic state has been constructed by fitting ∼37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm{sup −1}. The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies upmore » to 12 700 cm{sup −1} above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction.« less

New analytical model for the ozone electronic ground state potential surface and accurate ab initio vibrational predictions at high energy range.

PubMed

Tyuterev, Vladimir G; Kochanov, Roman V; Tashkun, Sergey A; Holka, Filip; Szalay, Péter G

2013-10-07

An accurate description of the complicated shape of the potential energy surface (PES) and that of the highly excited vibration states is of crucial importance for various unsolved issues in the spectroscopy and dynamics of ozone and remains a challenge for the theory. In this work a new analytical representation is proposed for the PES of the ground electronic state of the ozone molecule in the range covering the main potential well and the transition state towards the dissociation. This model accounts for particular features specific to the ozone PES for large variations of nuclear displacements along the minimum energy path. The impact of the shape of the PES near the transition state (existence of the "reef structure") on vibration energy levels was studied for the first time. The major purpose of this work was to provide accurate theoretical predictions for ozone vibrational band centres at the energy range near the dissociation threshold, which would be helpful for understanding the very complicated high-resolution spectra and its analyses currently in progress. Extended ab initio electronic structure calculations were carried out enabling the determination of the parameters of a minimum energy path PES model resulting in a new set of theoretical vibrational levels of ozone. A comparison with recent high-resolution spectroscopic data on the vibrational levels gives the root-mean-square deviations below 1 cm(-1) for ozone band centres up to 90% of the dissociation energy. New ab initio vibrational predictions represent a significant improvement with respect to all previously available calculations.

Theoretical and experimental studies on the mechanism of norbornadiene Pauson-Khand cycloadducts photorearrangement. Is there a pathway on the excited singlet potential energy surface?

PubMed

Olivella, Santiago; Solé, Albert; Lledó, Agustí; Ji, Yining; Verdaguer, Xavier; Suau, Rafael; Riera, Antoni

2008-12-17

The intermolecular Pauson-Khand reaction (PKR), a carbonylative cycloaddition between an alkyne and an alkene, is a convenient method to prepare cyclopentenones. Using norbornadiene as alkene, a myriad of tricyclo[5.2.1.0(2,6)]deca-4,8-dien-3-ones 1 can be easily prepared. The mechanism of the photochemical rearrangement of these adducts 1 into tricyclo[5.2.1.0(2,6)]deca-3,8-dien-10-ones 2 has been studied. The ground state (S(0)) and the three lowest excited states ((3)(pi pi*), (1)(n pi*), and (3)(n pi*)) potential energy surfaces (PESs) concerning the prototypical rearrangement of 1a (the cycloadduct of the PK carbonylative cycloaddition of norbornadiene and ethyne) to 2a have been thoroughly explored by means of CASSCF and CASPT2 calculations. From this study, two possible nonadiabatic pathways for the photochemical rearrangement arise: one starting on the (3)(pi pi*) PES and the other on the (1)(n pi*) PES. Both involve initial C-C gamma-bond cleavage of the enone, which leads to the formation of a bis-allyl or an allyl-butadienyloxyl diradical, respectively, that then decays to the S(0) PES through a (3)(pi pi*)/S(0) surface crossing or a (1)(n pi*)/S(0) conical intersection, each one lying in the vicinity of the corresponding diradical minimum. Once on the S(0) PES, the ring-closure to 2a occurs with virtually no energy barrier. The viability of both pathways was experimentally studied by means of triplet sensitization and quenching studies on the photorearrangement of the substituted Pauson-Khand cycloadduct 1b (R = TMS, R' = H) to 2b. Using high concentrations of either piperylene as a triplet quencher, or benzophenone as a triplet sensitizer, the reaction rate significantly slowed down. A Stern-Volmer type plot of product 2b concentration vs triplet quencher concentration showed an excellent linear correlation, thus indicating that only one excited state is involved in the photorearrangement. We conclude that, though there is a nonadiabatic pathway starting on the (1)(n pi*) PES, the reaction product is formed through the (3)(pi pi*) state because the energy barrier involved in the initial C-C gamma-bond cleavage of the enone is much lower in the (3)(pi pi*) PES than in the (1)(n pi*) PES.

Nickel adsorption onto polyurethane ethylene and vinyl acetate sorbents.

PubMed

Iqbal, Munawar; Ali, Zahid; Qamar, M Afzal; Ali, Abid; Hussain, Fida; Abbas, Mazhar; Nisar, Jan

2017-07-01

The present study was conducted to appraise the efficiencies of polyurethane ethylene sorbent (PES) and vinyl acetate sorbent (VAS) for nickel (Ni) adsorption. Process variables, i.e. Ni(II) ions initial concentration, pH, contact time and adsorbent dosage were optimized by response surface methodology (RSM) approach. The Ni(II) adsorption was fitted to the kinetic models (pseudo-first-order and pseudo-second-order) and adsorption isotherms (Freundlich and Langmuir). At optimum conditions of process variables, 171.99 mg/g (64.7%) and 388.08 mg/g (92.7%) Ni(II) was adsorbed onto PES and VAS, respectively. The RSM analysis revealed that maximum Ni(II) adsorption can be achieved at 299 mg/L Ni(II) ions initial concentration, 4.5 pH, 934 min contact time and 1.3 g adsorbent dosage levels for PES, whereas the optimum values for VAS were found to be 402 mg/L Ni(II) ions initial concentration, 4.6 pH, 881 min contact time and 1.2 g adsorbent dosage, respectively. The -OH and -C = O- were involved in the Ni(II) adsorption onto PES and VAS adsorbents. At optimum levels, up to 53.67% and 80.0% Ni(II) was removed from chemical industry wastewater using PES and VAS, respectively, which suggest that PES and VAS could possibly be used for Ni(II) adsorption from industrial wastewater.

Do Pre-Service Elementary School Teachers Still Have Mathematics Anxiety? Some Factors and Correlates

ERIC Educational Resources Information Center

Çatlioglu, Hakan; Gürbüz, Ramazan; Birgin, Osman

2014-01-01

This study aims to provide new evidence from Turkish pre-service elementary school (PES) teachers and to identify some correlations and factors associated with mathematics anxiety (MA). 480 Turkish PES teachers participated in this study. Data was collected using a "Personal Information Form," "Mathematics Anxiety Scale," and…

Computed potential energy surfaces for chemical reactions

NASA Technical Reports Server (NTRS)

Walch, Stephen P.; Levin, Eugene

1993-01-01

A new global potential energy surface (PES) is being generated for O(P-3) + H2 yields OH + H. This surface is being fit using the rotated Morse oscillator method, which was used to fit the previous POL-CI surface. The new surface is expected to be more accurate and also includes a much more complete sampling of bent geometries. A new study has been undertaken of the reaction N + O2 yields NO + O. The new studies have focused on the region of the surface near a possible minimum corresponding to the peroxy form of NOO. A large portion of the PES for this second reaction has been mapped out. Since state to state cross sections for the reaction are important in the chemistry of high temperature air, these studies will probably be extended to permit generation of a new global potential for reaction.

Functional electrospun membranes

NASA Astrophysics Data System (ADS)

Ognibene, G.; Fragalà, M. E.; Cristaldi, D. A.; Blanco, I.; Cicala, G.

2016-05-01

In this study we combined electrospun PES nanofibers with ZnO nanostructures in order to obtain a hierarchical nanostructured hybrid material to be use for active water filtration membranes. It benefits of flexibility and high surface area of the polymeric nanofibers as well as of additional functionalities of ZnOnanostructures. First, randomly oriented nanofibers with diameters of 716nm ±365 nm were electrospun on a glass fibers substrate from a solution of PES and DMF-TOL(1:1). ZnO nanorods were grown onto the surface of electrospun PES fibers by a Chemical Bath Deposition (CBD) process. It was preceed by a seeding process necessary to form nucleation sites for the subsequent radially aligned growth of ZnO nanowires. The morfology of the fibers and the effect of the seeding time have been analysed by SEM. The amount of ZnO nanowires grown over electrospun nanofibers was determined as 45% by weight. The high purity and crystallinity of the asobtained products are confirmed by XRD since all reflection peaks can be indexed to hexagonal wurtzite ZnO.

Quantum and classical dynamics of water dissociation on Ni(111): A test of the site-averaging model in dissociative chemisorption of polyatomic molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Bin; Department of Chemical Physics, University of Science and Technology of China, Hefei 230026; Guo, Hua, E-mail: hguo@unm.edu

Recently, we reported the first highly accurate nine-dimensional global potential energy surface (PES) for water interacting with a rigid Ni(111) surface, built on a large number of density functional theory points [B. Jiang and H. Guo, Phys. Rev. Lett. 114, 166101 (2015)]. Here, we investigate site-specific reaction probabilities on this PES using a quasi-seven-dimensional quantum dynamical model. It is shown that the site-specific reactivity is largely controlled by the topography of the PES instead of the barrier height alone, underscoring the importance of multidimensional dynamics. In addition, the full-dimensional dissociation probability is estimated by averaging fixed-site reaction probabilities with appropriatemore » weights. To validate this model and gain insights into the dynamics, additional quasi-classical trajectory calculations in both full and reduced dimensions have also been performed and important dynamical factors such as the steering effect are discussed.« less

A permutationally invariant full-dimensional ab initio potential energy surface for the abstraction and exchange channels of the H + CH{sub 4} system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jun, E-mail: jli15@cqu.edu.cn, E-mail: zhangdh@dicp.ac.cn; Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131; Chen, Jun

2015-05-28

We report a permutationally invariant global potential energy surface (PES) for the H + CH{sub 4} system based on ∼63 000 data points calculated at a high ab initio level (UCCSD(T)-F12a/AVTZ) using the recently proposed permutation invariant polynomial-neural network method. The small fitting error (5.1 meV) indicates a faithful representation of the ab initio points over a large configuration space. The rate coefficients calculated on the PES using tunneling corrected transition-state theory and quasi-classical trajectory are found to agree well with the available experimental and previous quantum dynamical results. The calculated total reaction probabilities (J{sub tot} = 0) including themore » abstraction and exchange channels using the new potential by a reduced dimensional quantum dynamic method are essentially the same as those on the Xu-Chen-Zhang PES [Chin. J. Chem. Phys. 27, 373 (2014)].« less

Cortical thickness correlates of psychotic experiences: examining the effect of season of birth using a genetically informative design.

PubMed

Córdova-Palomera, A; Alemany, S; Falcón, C; Bargalló, N; Goldberg, X; Crespo-Facorro, B; Nenadic, I; Fañanás, L

2014-09-01

Season of birth has been shown to influence risk for several neuropsychiatric diseases. Furthermore, it has been suggested that season of birth modifies a number of brain morphological traits. Since cortical thickness alterations have been reported across some levels of the psychosis-spectrum, this study was aimed at i) assessing the scarcely explored relationship between cortical thickness and severity of subclinical psychotic experiences (PEs) in healthy subjects, and ii) evaluating the potential impact of season of birth in the preceding thickness-PEs relationship. As both PEs and brain cortical features are heritable, the current work used monozygotic twins to separately evaluate familial and unique environmental factors. High-resolution structural MRI scans of 48 twins (24 monozygotic pairs) were analyzed to estimate cortical thickness using FreeSurfer. They were then examined in relation to PEs, accounting for the effects of birth season; putative differential relationships between PEs and cortical thickness depending on season of birth were also tested. Current results support previous findings indicative of cortical thickening in healthy individuals with high psychometrically assessed psychosis scores, probably in line with theories of compensatory aspects of brain features in non-clinical populations. Additionally, they suggest distinct patterns of cortical thickness-PEs relationships depending on birth seasonality. Familial factors underlying the presence of PEs may drive these effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Experimental evaluation of blockage ratio and plenum evacuation system flow effects on pressure distribution for bodies of revolution in 0.1 scale model test section of NASA Lewis Research Center's proposed altitude wind tunnel

NASA Technical Reports Server (NTRS)

Burley, Richard R.; Harrington, Douglas E.

1987-01-01

An experimental investigation was conducted in the slotted test section of the 0.1-scale model of the proposed Altitude Wind Tunnel to evaluate wall interference effects at tunnel Mach numbers from 0.70 to 0.95 on bodies of revolution with blockage rates of 0.43, 3, 6, and 12 percent. The amount of flow that had to be removed from the plenum chamber (which surrounded the slotted test section) by the plenum evacuation system (PES) to eliminate wall interference effects was determined. The effectiveness of tunnel reentry flaps in removing flow from the plenum chamber was examined. The 0.43-percent blockage model was the only one free of wall interference effects with no PES flow. Surface pressures on the forward part of the other models were greater than interference-free results and were not influenced by PES flow. Interference-free results were achieved on the aft part of the 3- and 6-percent blockage models with the proper amount of PES flow. The required PES flow was substantially reduced by opening the reentry flaps.

New ab initio potential surfaces and three-dimensional quantum dynamics for transition state spectroscopy in ozone photodissociation

NASA Astrophysics Data System (ADS)

Yamashita, Koichi; Morokuma, Keiji; Le Quéré, Frederic; Leforestier, Claude

1992-04-01

New ab initio potential energy surfaces (PESs) of the ground and B ( 1B 2) states of ozone have been calculated with the CASSCF-SECI/DZP method to describe the three-dimensional photodissociation process. The dissociation energy of the ground state and the vertical barrier height of the B PES are obtained to be 0.88 and 1.34 eV, respectively, in better agreement with the experimental values than the previous calculation. The photodissociation autocorrelation function, calculated on the new B PES, based on exact three-dimensional quantum dynamics, reproduces well the main recurrence feature extracted from the experimental spectra.

High Accuracy Potential Energy Surface, Dipole Moment Surface, Rovibrational Energies and Line List Calculations for ^{14}NH_3

NASA Astrophysics Data System (ADS)

Coles, Phillip; Yurchenko, Sergei N.; Polyansky, Oleg; Kyuberis, Aleksandra; Ovsyannikov, Roman I.; Zobov, Nikolay Fedorovich; Tennyson, Jonathan

2017-06-01

We present a new spectroscopic potential energy surface (PES) for ^{14}NH_3, produced by refining a high accuracy ab initio PES to experimental energy levels taken predominantly from MARVEL. The PES reproduces 1722 matched J=0-8 experimental energies with a root-mean-square error of 0.035 cm-1 under 6000 cm^{-1} and 0.059 under 7200 cm^{-1}. In conjunction with a new DMS calculated using multi reference configuration interaction (MRCI) and H=aug-cc-pVQZ, N=aug-cc-pWCVQZ basis sets, an infrared (IR) line list has been computed which is suitable for use up to 2000 K. The line list is used to assign experimental lines in the 7500 - 10,500 cm^{-1} region and previously unassigned lines in HITRAN in the 6000-7000 cm^{-1} region. Oleg L. Polyansky, Roman I. Ovsyannikov, Aleksandra A. Kyuberis, Lorenzo Lodi, Jonathan Tennyson, Andrey Yachmenev, Sergei N. Yurchenko, Nikolai F. Zobov, J. Mol. Spec., 327 (2016) 21-30 Afaf R. Al Derzia, Tibor Furtenbacher, Jonathan Tennyson, Sergei N. Yurchenko, Attila G. Császár, J. Quant. Spectrosc. Rad. Trans., 161 (2015) 117-130

High-level ab initio potential energy surface and dynamics of the F– + CH3I SN2 and proton-transfer reactions† †Electronic supplementary information (ESI) available: Benchmark classical and adiabatic relative energies (Table S1), vibrational frequencies of all the stationary points (Tables S2 and S3), direct/indirect trajectory separation function parameters (Table S4), entrance-channel potential (Fig. S1), structures of the minima and saddle points corresponding to the abstraction channel (Fig. S2), reaction probabilities (Fig. S3), trajectory integration time distributions (Fig. S4), trajectory integration time vs. I– velocity distributions (Fig. S5), and mechanism-specific reaction probabilities (Fig. S6). See DOI: 10.1039/c7sc00033b Click here for additional data file.

PubMed Central

Olasz, Balázs; Szabó, István

2017-01-01

Bimolecular nucleophilic substitution (SN2) and proton transfer are fundamental processes in chemistry and F– + CH3I is an important prototype of these reactions. Here we develop the first full-dimensional ab initio analytical potential energy surface (PES) for the F– + CH3I system using a permutationally invariant fit of high-level composite energies obtained with the combination of the explicitly-correlated CCSD(T)-F12b method, the aug-cc-pVTZ basis, core electron correlation effects, and a relativistic effective core potential for iodine. The PES accurately describes the SN2 channel producing I– + CH3F via Walden-inversion, front-side attack, and double-inversion pathways as well as the proton-transfer channel leading to HF + CH2I–. The relative energies of the stationary points on the PES agree well with the new explicitly-correlated all-electron CCSD(T)-F12b/QZ-quality benchmark values. Quasiclassical trajectory computations on the PES show that the proton transfer becomes significant at high collision energies and double-inversion as well as front-side attack trajectories can occur. The computed broad angular distributions and hot internal energy distributions indicate the dominance of indirect mechanisms at lower collision energies, which is confirmed by analyzing the integration time and leaving group velocity distributions. Comparison with available crossed-beam experiments shows usually good agreement. PMID:28507692

Fatty acid profiles of Garuga floribunda, Ipomoea pes-caprae, Melanolepis multiglandulosa and Premna odorata seed oils

USDA-ARS?s Scientific Manuscript database

The fatty acid profiles of the seed oils of four species from four plant families for which no or only sparse information on the fatty acid profiles is available are reported. The five seed oils are Garuga floribunda of the Burseraceae family, Ipomoea pes-caprae of the Convolvulaceae family, Melanol...

The effect of polymer surface modification on polymer-protein interaction via interfacial polymerization and hydrophilic polymer grafting

USDA-ARS?s Scientific Manuscript database

Protein membrane separation is prone to fouling on the membrane surface resulting from protein adsorption onto the surface. Surface modification of synthetic membranes is one way to reduce fouling. We investigated surface modification of polyethersulfone (PES) as a way of improving hydrophilicity ...

New insights into the effects of biomaterial chemistry and topography on the morphology of kidney epithelial cells.

PubMed

Hulshof, Frits; Schophuizen, Carolien; Mihajlovic, Milos; van Blitterswijk, Clemens; Masereeuw, Rosalinde; de Boer, Jan; Stamatialis, Dimitrios

2018-02-01

Increasing incidence of renal pathology in the western world calls for innovative research for the development of cell-based therapies such as a bioartificial kidney (BAK) device. To fulfil the multitude of kidney functions, the core component of the BAK is a living membrane consisting of a tight kidney cell monolayer with preserved functional organic ion transporters cultured on a polymeric membrane surface. This membrane, on one side, is in contact with blood and therefore should have excellent blood compatibility, whereas the other side should facilitate functional monolayer formation. This work investigated the effect of membrane chemistry and surface topography on kidney epithelial cells to improve the formation of a functional monolayer. To achieve this, microtopographies were fabricated with high resolution and reproducibility on polystyrene films and on polyethersulfone-polyvinyl pyrrolidone (PES-PVP) porous membranes. A conditionally immortalized proximal tubule epithelial cell line (ciPTEC) was cultured on both, and subsequently, the cell morphology and monolayer formation were assessed. Our results showed that L-dopamine coating of the PES-PVP was sufficient to support ciPTEC monolayer formation. The polystyrene topographies with large features were able to align the cells in various patterns without significantly disruption of monolayer formation; however, the PES-PVP topographies with large features disrupted the monolayer. In contrast, the PES-PVP membranes with small features and with large spacing supported well the ciPTEC monolayer formation. In addition, the topographical PES-PVP membranes were compatible as a substrate membrane to measure organic cation transporter activity in Transwell® systems. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of surface pretreatment of TiO2 films on interfacial processes leading to bacterial inactivation in the dark and under light irradiation.

PubMed

Rtimi, Sami; Nesic, Jelena; Pulgarin, Cesar; Sanjines, Rosendo; Bensimon, Michael; Kiwi, John

2015-02-06

Evidence is presented for radio-frequency plasma pretreatment enhancing the amount and adhesion of TiO2 sputtered on polyester (PES) and on polyethylene (PE) films. Pretreatment is necessary to attain a suitable TiO2 loading leading to an acceptable Escherichia coli reduction kinetics in the dark or under light irradiation for PES-TiO2 and PE-TiO2 samples. The amount of TiO2 on the films was monitored by diffuse reflectance spectroscopy and X-ray fluorescence. X-ray electron spectroscopy shows the lack of accumulation of bacterial residues such as C, N and S during bacterial inactivation since they seem to be rapidly destroyed by TiO2 photocatalysis. Evidence was found for Ti(4+)/Ti(3+) redox catalysis occurring on PES-TiO2 and PE-TiO2 during the bacterial inactivation process. On PE-TiO2 surfaces, Fourier transform infrared spectroscopy (ATR-FTIR) provides evidence for a systematic shift of the na(CH2) stretching vibrations preceding bacterial inactivation within 60 min. The discontinuous IR-peak shifts reflect the increase in the C-H inter-bond distance leading to bond scission. The mechanism leading to E. coli loss of viability on PES-TiO2 was investigated in the dark up to complete bacterial inactivation by monitoring the damage in the bacterial outer cell by transmission electron microscopy. After 30 min, the critical step during the E. coli inactivation commences for dark disinfection on 0.1-5% wt PES-TiO2 samples. The interactions between the TiO2 aggregates and the outer lipopolysaccharide cell wall involve electrostatic effects competing with the van der Waals forces.

Dynamics of a Room Temperature Ionic Liquid in Supported Ionic Liquid Membranes vs the Bulk Liquid: 2D IR and Polarized IR Pump-Probe Experiments.

PubMed

Shin, Jae Yoon; Yamada, Steven A; Fayer, Michael D

2017-01-11

Supported ionic liquid membranes (SILMs) are membranes that have ionic liquids impregnated in their pores. SILMs have been proposed for advanced carbon capture materials. Two-dimensional infrared (2D IR) and polarization selective IR pump-probe (PSPP) techniques were used to investigate the dynamics of reorientation and spectral diffusion of the linear triatomic anion, SeCN - , in poly(ether sulfone) (PES) membranes and room-temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EmimNTf 2 ). The dynamics in the bulk EmimNTf 2 were compared to its dynamics in the SILM samples. Two PES membranes, PES200 and PES30, have pores with average sizes, ∼300 nm and ∼100 nm, respectively. Despite the relatively large pore sizes, the measurements reveal that the reorientation of SeCN - and the RTIL structural fluctuations are substantially slower in the SILMs than in the bulk liquid. The complete orientational randomization, slows from 136 ps in the bulk to 513 ps in the PES30. 2D IR measurements yield three time scales for structural spectral diffusion (SSD), that is, the time evolution of the liquid structure. The slowest decay constant increases from 140 ps in the bulk to 504 ps in the PES200 and increases further to 1660 ps in the PES30. The results suggest that changes at the interface propagate out and influence the RTIL structural dynamics even more than a hundred nanometers from the polymer surface. The differences between the IL dynamics in the bulk and in the membranes suggest that studies of bulk RTIL properties may be poor guides to their use in SILMs in carbon capture applications.

Ab Initio Calculations of Water Line Strengths

NASA Technical Reports Server (NTRS)

Schwenke, David W.; Partridge, Harry

1998-01-01

We report on the determination of a high quality ab initiu potential energy surface (PES) and dipole moment function for water. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base with J less than 6 for H2O. The changes in the PES are small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Using this adjusted PES, we can match 30,092 of the 30,117 transitions in the HITRAN 96 data base for H2O with theoretical lines. The 10,25,50,75, and 90 percentiles of the difference between the calculated and tabulated line positions are -0.11, -0.04, -0.01, 0.02, and 0.07 l/cm. Non-adiabatic effects are not explicitly included. About 3% of the tabulated line positions appear to be incorrect. Similar agreement using this adjusted PES is obtained for the oxygen 17 and oxygen 18 isotopes. For HDO, the agreement is not as good, with root-mean-square error of 0.25 l/cm for lines with J less than 6. This error is reduced to 0.02 l/cm by including a small asymmetric correction to the PES, which is parameterized by simultaneously fitting to HDO md D2O data. Scaling this correction by mass factors yields good results for T2O and HTO. The intensities summed over vibrational bands are usually in good agreement between the calculations and the tabulated results, but individual lines strengths can differ greatly. A high temperature list consisting of 307,721,352 lines is generated for H2O using our PES and dipole moment function.

High-level ab initio potential energy surface and dynamics of the F- + CH3I SN2 and proton-transfer reactions.

PubMed

Olasz, Balázs; Szabó, István; Czakó, Gábor

2017-04-01

Bimolecular nucleophilic substitution (S N 2) and proton transfer are fundamental processes in chemistry and F - + CH 3 I is an important prototype of these reactions. Here we develop the first full-dimensional ab initio analytical potential energy surface (PES) for the F - + CH 3 I system using a permutationally invariant fit of high-level composite energies obtained with the combination of the explicitly-correlated CCSD(T)-F12b method, the aug-cc-pVTZ basis, core electron correlation effects, and a relativistic effective core potential for iodine. The PES accurately describes the S N 2 channel producing I - + CH 3 F via Walden-inversion, front-side attack, and double-inversion pathways as well as the proton-transfer channel leading to HF + CH 2 I - . The relative energies of the stationary points on the PES agree well with the new explicitly-correlated all-electron CCSD(T)-F12b/QZ-quality benchmark values. Quasiclassical trajectory computations on the PES show that the proton transfer becomes significant at high collision energies and double-inversion as well as front-side attack trajectories can occur. The computed broad angular distributions and hot internal energy distributions indicate the dominance of indirect mechanisms at lower collision energies, which is confirmed by analyzing the integration time and leaving group velocity distributions. Comparison with available crossed-beam experiments shows usually good agreement.

Low-rank canonical-tensor decomposition of potential energy surfaces: application to grid-based diagrammatic vibrational Green's function theory

DOE PAGES

Rai, Prashant; Sargsyan, Khachik; Najm, Habib; ...

2017-03-07

Here, a new method is proposed for a fast evaluation of high-dimensional integrals of potential energy surfaces (PES) that arise in many areas of quantum dynamics. It decomposes a PES into a canonical low-rank tensor format, reducing its integral into a relatively short sum of products of low-dimensional integrals. The decomposition is achieved by the alternating least squares (ALS) algorithm, requiring only a small number of single-point energy evaluations. Therefore, it eradicates a force-constant evaluation as the hotspot of many quantum dynamics simulations and also possibly lifts the curse of dimensionality. This general method is applied to the anharmonic vibrationalmore » zero-point and transition energy calculations of molecules using the second-order diagrammatic vibrational many-body Green's function (XVH2) theory with a harmonic-approximation reference. In this application, high dimensional PES and Green's functions are both subjected to a low-rank decomposition. Evaluating the molecular integrals over a low-rank PES and Green's functions as sums of low-dimensional integrals using the Gauss–Hermite quadrature, this canonical-tensor-decomposition-based XVH2 (CT-XVH2) achieves an accuracy of 0.1 cm -1 or higher and nearly an order of magnitude speedup as compared with the original algorithm using force constants for water and formaldehyde.« less

Low-rank canonical-tensor decomposition of potential energy surfaces: application to grid-based diagrammatic vibrational Green's function theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rai, Prashant; Sargsyan, Khachik; Najm, Habib

Here, a new method is proposed for a fast evaluation of high-dimensional integrals of potential energy surfaces (PES) that arise in many areas of quantum dynamics. It decomposes a PES into a canonical low-rank tensor format, reducing its integral into a relatively short sum of products of low-dimensional integrals. The decomposition is achieved by the alternating least squares (ALS) algorithm, requiring only a small number of single-point energy evaluations. Therefore, it eradicates a force-constant evaluation as the hotspot of many quantum dynamics simulations and also possibly lifts the curse of dimensionality. This general method is applied to the anharmonic vibrationalmore » zero-point and transition energy calculations of molecules using the second-order diagrammatic vibrational many-body Green's function (XVH2) theory with a harmonic-approximation reference. In this application, high dimensional PES and Green's functions are both subjected to a low-rank decomposition. Evaluating the molecular integrals over a low-rank PES and Green's functions as sums of low-dimensional integrals using the Gauss–Hermite quadrature, this canonical-tensor-decomposition-based XVH2 (CT-XVH2) achieves an accuracy of 0.1 cm -1 or higher and nearly an order of magnitude speedup as compared with the original algorithm using force constants for water and formaldehyde.« less

Interface Trap Density Reduction for Al2O3/GaN (0001) Interfaces by Oxidizing Surface Preparation prior to Atomic Layer Deposition.

PubMed

Zhernokletov, Dmitry M; Negara, Muhammad A; Long, Rathnait D; Aloni, Shaul; Nordlund, Dennis; McIntyre, Paul C

2015-06-17

We correlate interfacial defect state densities with the chemical composition of the Al2O3/GaN interface in metal-oxide-semiconductor (MOS) structures using synchrotron photoelectron emission spectroscopy (PES), cathodoluminescence and high-temperature capacitance-voltage measurements. The influence of the wet chemical pretreatments involving (1) HCl+HF etching or (2) NH4OH(aq) exposure prior to atomic layer deposition (ALD) of Al2O3 were investigated on n-type GaN (0001) substrates. Prior to ALD, PES analysis of the NH4OH(aq) treated surface shows a greater Ga2O3 component compared to either HCl+HF treated or as-received surfaces. The lowest surface concentration of oxygen species is detected on the acid etched surface, whereas the NH4OH treated sample reveals the lowest carbon surface concentration. Both surface pretreatments improve electrical characteristics of MOS capacitors compared to untreated samples by reducing the Al2O3/GaN interface state density. The lowest interfacial trap density at energies in the upper band gap is detected for samples pretreated with NH4OH. These results are consistent with cathodoluminescence data indicating that the NH4OH treated samples show the strongest band edge emission compared to as-received and acid etched samples. PES results indicate that the combination of reduced carbon contamination while maintaining a Ga2O3 interfacial layer by NH4OH(aq) exposure prior to ALD results in fewer interface traps after Al2O3 deposition on the GaN substrate.

Association Between Psychotic Experiences and Subsequent Suicidal Thoughts and Behaviors: A Cross-National Analysis From the World Health Organization World Mental Health Surveys.

PubMed

Bromet, Evelyn J; Nock, Matthew K; Saha, Sukanta; Lim, Carmen C W; Aguilar-Gaxiola, Sergio; Al-Hamzawi, Ali; Alonso, Jordi; Borges, Guilherme; Bruffaerts, Ronny; Degenhardt, Louisa; de Girolamo, Giovanni; de Jonge, Peter; Florescu, Silvia; Gureje, Oye; Haro, Josep M; He, Yanling; Hu, Chiyi; Karam, Elie G; Kovess-Masfety, Viviane; Lee, Sing; Lepine, Jean-Pierre; Mneimneh, Zeina; Navarro-Mateu, Fernando; Ojagbemi, Akin; Posada-Villa, José; Sampson, Nancy A; Scott, Kate M; Stagnaro, Juan C; Viana, Maria C; Xavier, Miguel; Kessler, Ronald C; McGrath, John J

2017-11-01

Community-based studies have linked psychotic experiences (PEs) with increased risks of suicidal thoughts and behaviors (STBs). However, it is not known if these associations vary across the life course or if mental disorders contribute to these associations. To examine the temporal association between PEs and subsequent STBs across the life span as well as the influence of mental disorders (antecedent to the STBs) on these associations. A total of 33 370 adult respondents across 19 countries from the World Health Organization World Mental Health Surveys were assessed for PEs, STBs (ie, ideation, plans, and attempts), and 21 DSM-IV mental disorders. Discrete-time survival analysis was used to investigate the associations of PEs with subsequent onset of STBs. Prevalence and frequency of STBs with PEs, and odds ratios and 95% CIs. Of 33 370 included participants, among those with PEs (n = 2488), the lifetime prevalence (SE) of suicidal ideation, plans, and attempts was 28.5% (1.3), 10.8% (0.7), and 10.2% (0.7), respectively. Respondents with 1 or more PEs had 2-fold increased odds of subsequent STBs after adjusting for antecedent or intervening mental disorders (suicidal ideation: odds ratio, 2.2; 95% CI, 1.8-2.6; suicide plans: odds ratio, 2.1; 95% CI, 1.7-2.6; and suicide attempts: odds ratio, 1.9; 95% CI, 1.5-2.5). There were significant dose-response relationships of number of PE types with subsequent STBs that persisted after adjustment for mental disorders. Although PEs were significant predictors of subsequent STB onset across all life stages, associations were strongest in individuals 12 years and younger. After adjustment for antecedent mental disorders, the overall population attributable risk proportions for lifetime suicidal ideation, plans, and attempts associated with temporally prior PEs were 5.3%, 5.7%, and 4.8%, respectively. Psychotic experiences are associated with elevated odds of subsequent STBs across the life course that cannot be explained by antecedent mental disorders. These results highlight the importance of including information about PEs in screening instruments designed to predict STBs.

Potential energy hypersurface and molecular flexibility

NASA Astrophysics Data System (ADS)

Koča, Jaroslav

1993-02-01

The molecular flexibility phenomenon is discussed from the conformational potential energy(hyper) surface (PES) point of view. Flexibility is considered as a product of three terms: thermodynamic, kinetic and geometrical. Several expressions characterizing absolute and relative molecular flexibility are introduced, depending on a subspace studied of the entire conformational space, energy level E of PES as well as absolute temperature. Results obtained by programs DAISY, CICADA and PANIC in conjunction with molecular mechanics program MMX for flexibility analysis of isopentane, 2,2-dimethylpentane and isohexane molecules are introduced.

Fouling behavior of poly(ether)sulfone ultrafiltration membrane during concentration of whey proteins: Effect of hydrophilic modification using atmospheric pressure argon jet plasma.

PubMed

Damar Huner, Irem; Gulec, Haci Ali

2017-12-01

The aim of the study was to investigate the effects of hydrophilic surface modification via atmospheric pressure jet plasma (ApJPls) on the fouling propensity of polyethersulfone (PES) ultrafiltration (UF) membranes during concentration of whey proteins. The distance from nozzle to substrate surface of 30mm and the exposure period of 5 times were determined as the most effective parameters enabling an increase in ΔG iwi value of the plain membrane from (-) 14.92±0.89mJ/m 2 to (+) 17.57±0.67mJ/m 2 . Maximum hydrophilicity and minimum surface roughness achieved by argon plasma action resulted in better antifouling behavior, while the hydraulic permeability and the initial permeate flux were decreased sharply due to the plasma-induced surface cross-linking. A quite steady state flux was obtained throughout the UF with the ApJPls modified PES membrane. The contribution of R frev to R t , which was 94% for the UF through the plain membrane, decreased to 43% after the plasma treatment. The overall results of this study highlighted the ApJPls modification decreased the fouling propensity of PES membrane without affecting the original protein rejection capability and improved the recovery of initial permeate flux after chemical cleaning. Copyright © 2017 Elsevier B.V. All rights reserved.

Ab initio intermolecular potential energy surface for the CO2—N2 system and related thermophysical properties

NASA Astrophysics Data System (ADS)

Crusius, Johann-Philipp; Hellmann, Robert; Castro-Palacio, Juan Carlos; Vesovic, Velisa

2018-06-01

A four-dimensional potential energy surface (PES) for the interaction between a rigid carbon dioxide molecule and a rigid nitrogen molecule was constructed based on quantum-chemical ab initio calculations up to the coupled-cluster level with single, double, and perturbative triple excitations. Interaction energies for a total of 1893 points on the PES were calculated using the counterpoise-corrected supermolecular approach and basis sets of up to quintuple-zeta quality with bond functions. The interaction energies were extrapolated to the complete basis set limit, and an analytical site-site potential function with seven sites for carbon dioxide and five sites for nitrogen was fitted to the interaction energies. The CO2—N2 cross second virial coefficient as well as the dilute gas shear viscosity, thermal conductivity, and binary diffusion coefficient of CO2—N2 mixtures were calculated for temperatures up to 2000 K to validate the PES and to provide reliable reference values for these important properties. The calculated values are in very good agreement with the best experimental data.

Association between psychotic experiences and subsequent suicidal thoughts and behaviors: A cross-national analysis from the World Health Organization World Mental Health Surveys

PubMed Central

Bromet, Evelyn J.; Nock, Matthew K.; Saha, Sukanta; Lim, Carmen C. W.; Aguilar-Gaxiola, Sergio; Al-Hamzawi, Ali; Alonso, Jordi; Borges, Guilherme; Bruffaerts, Ronny; Degenhardt, Louisa; de Girolamo, Giovanni; de Jonge, Peter; Florescu, Silvia; Gureje, Oye; Haro, Josep M.; He, Yanling; Hu, Chiyi; Karam, Elie G.; Kovess-Masfety, Viviane; Lee, Sing; Lepine, Jean-Pierre; Mneimneh, Zeina; Navarro-Mateu, Fernando; Ojagbemi, Akin; Posada-Villa, José; Sampson, Nancy A.; Scott, Kate M.; Stagnaro, Juan C.; Viana, Maria C.; Xavier, Miguel; Kessler, Ronald C.; McGrath, John J.

2017-01-01

IMPORTANCE Community-based studies have linked psychotic experiences (PEs) with increased risks of suicidal thoughts and behaviors (STBs). However, it is not known if these associations vary across the life-course or if mental disorders (antecedent to the STBs) contribute to these associations. OBJECTIVE To examine the temporal association between PEs and subsequent STBs across the life span as well as the influence of mental disorders (antecedent to the STBs) on these associations. DESIGN, SETTING, AND PARTICIPANTS A total of 33,370 adult respondents across 19 countries from the WHO World Mental Health (WMH) Surveys were assessed for PEs, STBs (ideation, plans, and attempts), and 21 DSM-IV mental disorders. Discrete-time survival analysis was used to investigate the associations of PEs with subsequent onsets of STBs. MAIN OUTCOMES AND MEASURES Prevalence and frequency of STBs with PEs, and odds ratios and 95%CIs. Results Of 33 370 included participants, among those with PEs (n = 2488), the lifetime prevalence (SE) of suicidal ideation, plans, and attempts was 28.5%(1.3), 10.8%(0.7), and 10.2%(0.7), respectively. Respondents with 1 or more PEs had 2-fold increased odds of subsequent STBs after adjusting for antecedent or intervening mental disorders (suicidal ideation: odds ratio, 2.2; 95%CI, 1.8-2.6; suicide plans: odds ratio, 2.1; 95%CI, 1.7-2.6; and suicide attempts: odds ratio, 1.9; 95%CI, 1.5-2.5). There were significant dose-response relationships of number of PE types with subsequent STBs that persisted after adjustment for mental disorders. Although PEs were significant predictors of subsequent STB onset across all life stages, associations were strongest in individuals 12 years and younger. After adjustment for antecedent mental disorders, the overall population attributable risk proportions for lifetime suicidal ideation, plans, and attempts associated with temporally prior PEs were 5.3%, 5.7%, and 4.8%, respectively. Conclusions PEs are associated with elevated odds of subsequent STBs across the life-course that cannot be explained by antecedent mental disorders. These results highlight the importance of including information about PEs in screening instruments designed to predict STBs. PMID:28854302

Full-dimensional quantum calculations of ground-state tunneling splitting of malonaldehyde using an accurate ab initio potential energy surface

NASA Astrophysics Data System (ADS)

Wang, Yimin; Braams, Bastiaan J.; Bowman, Joel M.; Carter, Stuart; Tew, David P.

2008-06-01

Quantum calculations of the ground vibrational state tunneling splitting of H-atom and D-atom transfer in malonaldehyde are performed on a full-dimensional ab initio potential energy surface (PES). The PES is a fit to 11 147 near basis-set-limit frozen-core CCSD(T) electronic energies. This surface properly describes the invariance of the potential with respect to all permutations of identical atoms. The saddle-point barrier for the H-atom transfer on the PES is 4.1 kcal/mol, in excellent agreement with the reported ab initio value. Model one-dimensional and ``exact'' full-dimensional calculations of the splitting for H- and D-atom transfer are done using this PES. The tunneling splittings in full dimensionality are calculated using the unbiased ``fixed-node'' diffusion Monte Carlo (DMC) method in Cartesian and saddle-point normal coordinates. The ground-state tunneling splitting is found to be 21.6 cm-1 in Cartesian coordinates and 22.6 cm-1 in normal coordinates, with an uncertainty of 2-3 cm-1. This splitting is also calculated based on a model which makes use of the exact single-well zero-point energy (ZPE) obtained with the MULTIMODE code and DMC ZPE and this calculation gives a tunneling splitting of 21-22 cm-1. The corresponding computed splittings for the D-atom transfer are 3.0, 3.1, and 2-3 cm-1. These calculated tunneling splittings agree with each other to within less than the standard uncertainties obtained with the DMC method used, which are between 2 and 3 cm-1, and agree well with the experimental values of 21.6 and 2.9 cm-1 for the H and D transfer, respectively.

Full-dimensional quantum calculations of ground-state tunneling splitting of malonaldehyde using an accurate ab initio potential energy surface.

PubMed

Wang, Yimin; Braams, Bastiaan J; Bowman, Joel M; Carter, Stuart; Tew, David P

2008-06-14

Quantum calculations of the ground vibrational state tunneling splitting of H-atom and D-atom transfer in malonaldehyde are performed on a full-dimensional ab initio potential energy surface (PES). The PES is a fit to 11 147 near basis-set-limit frozen-core CCSD(T) electronic energies. This surface properly describes the invariance of the potential with respect to all permutations of identical atoms. The saddle-point barrier for the H-atom transfer on the PES is 4.1 kcalmol, in excellent agreement with the reported ab initio value. Model one-dimensional and "exact" full-dimensional calculations of the splitting for H- and D-atom transfer are done using this PES. The tunneling splittings in full dimensionality are calculated using the unbiased "fixed-node" diffusion Monte Carlo (DMC) method in Cartesian and saddle-point normal coordinates. The ground-state tunneling splitting is found to be 21.6 cm(-1) in Cartesian coordinates and 22.6 cm(-1) in normal coordinates, with an uncertainty of 2-3 cm(-1). This splitting is also calculated based on a model which makes use of the exact single-well zero-point energy (ZPE) obtained with the MULTIMODE code and DMC ZPE and this calculation gives a tunneling splitting of 21-22 cm(-1). The corresponding computed splittings for the D-atom transfer are 3.0, 3.1, and 2-3 cm(-1). These calculated tunneling splittings agree with each other to within less than the standard uncertainties obtained with the DMC method used, which are between 2 and 3 cm(-1), and agree well with the experimental values of 21.6 and 2.9 cm(-1) for the H and D transfer, respectively.

Titan's Ionic Species: Theoretical Treatment of N2H+ and Related Ions

NASA Astrophysics Data System (ADS)

Brites, V.; Hochlaf, M.

2009-06-01

We use different ab initio methods to compute the three-dimensional potential energy surface (3D-PES) of the ground state of N2H+. This includes the standard coupled cluster, the complete active space self-consistent field, the internally contacted multi reference configuration interaction, and the newly developed CCSD(T)-F12 methods. For the description of H and N atoms, several basis sets are tested. Then, we incorporate the 3D-PES analytical representations into variational calculations of the rovibrational spectrum of N2H+(X˜1Σ+) up to 7200 cm-1 above the zero point vibrational energy. Our data show that the CCSD(T)-F12/aug-cc-pVTZ approach represents a compromise for good description of the PES and computation cost. This technique is recommended for full dimensional PES generation of atmospheric and astrophysical relevant polyatomic systems. We applied this method to derive the rovibrational spectra of N2H+(X˜1Σ+) and of N2H++(X˜2Σ+). Finally, we discuss the existence of the N2H++(X˜2Σ+) in Titan's atmosphere.

Rotational cross sections and rate coefficients of aluminium monoxide AlO(X2Σ+) induced by its collision with He(1 S) at low temperature

NASA Astrophysics Data System (ADS)

Tchakoua, Théophile; Nkot Nkot, Pierre René; Fifen, Jean Jules; Nsangou, Mama; Motapon, Ousmanou

2018-06-01

We present the first potential energy surface (PES) for the AlO(X2Σ+)-He(1 S) van der Waals complex. This PES has been calculated at the RCCSD(T) level of theory. The mixed Gaussian/Exponential Extrapolation Scheme of complete basis set [CBS(D,T,Q)] was employed. The PES was fitted using global analytical method. This fitted PES was used subsequently in the close-coupling approach for the computation of the state-to-state collisional excitation cross sections of the fine-structure levels of the AlO-He complex. Collision energies were taken up to 2500 cm-1 and they yield after thermal averaging, state-to-state rate coefficients up to 300 K. The propensity rules between the lowest fine-structure levels were studied. These rules show, on one hand, a strong propensity in favour of odd ΔN transitions, and on the other hand, that cross sections and collisional rate coefficients for Δj = ΔN transitions are larger than those for Δj ≠ ΔN transitions.

Relativistic potential energy surfaces of initial oxidations of Si(100) by atomic oxygen: The importance of surface dimer triplet state

NASA Astrophysics Data System (ADS)

Kim, Tae-Rae; Shin, Seokmin; Choi, Cheol Ho

2012-06-01

The non-relativistic and relativistic potential energy surfaces (PESs) of the symmetric and asymmetric reaction paths of Si(100)-2×1 oxidations by atomic oxygen were theoretically explored. Although only the singlet PES turned out to exist as a major channel leading to "on-dimer" product, both the singlet and triplet PESs leading to "on-top" products are attractive. The singlet PESs leading to the two surface products were found to be the singlet combinations (open-shell singlet) of the low-lying triplet state of surface silicon dimer and the ground 3P state of atomic oxygen. The triplet state of the "on-top" product can also be formed by the ground singlet state of the surface silicon dimer and the same 3P oxygen. The attractive singlet PESs leading to the "on-dimer" and "on-top" products made neither the intersystem crossings from triplet to singlet PES nor high energy 1D of atomic oxygen necessary. Rather, the low-lying triplet state of surface silicon dimer plays an important role in the initial oxidations of silicon surface.

Stabilizing Single Ni Adatoms on a Two-Dimensional Porous Titania Overlayer at the SrTiO3(110) Surface

PubMed Central

2014-01-01

Nickel vapor-deposited on the SrTiO3(110) surface was studied using scanning tunneling microscopy, photoemission spectroscopy (PES), and density functional theory calculations. This surface forms a (4 × 1) reconstruction, composed of a 2-D titania structure with periodic six- and ten-membered nanopores. Anchored at these nanopores, Ni single adatoms are stabilized at room temperature. PES measurements show that the Ni adatoms create an in-gap state located at 1.9 eV below the conduction band minimum and induce an upward band bending. Both experimental and theoretical results suggest that Ni adatoms are positively charged. Our study produces well-dispersed single-adatom arrays on a well-characterized oxide support, providing a model system to investigate single-adatom catalytic and magnetic properties. PMID:25177410

A nine-dimensional ab initio global potential energy surface for the H2O+ + H2 → H3O+ + H reaction

NASA Astrophysics Data System (ADS)

Li, Anyang; Guo, Hua

2014-06-01

An accurate full-dimensional global potential energy surface (PES) is developed for the title reaction. While the long-range interactions in the reactant asymptote are represented by an analytical expression, the interaction region of the PES is fit to more than 81 000 of ab initio points at the UCCSD(T)-F12b/AVTZ level using the permutation invariant polynomial neural network approach. Fully symmetric with respect to permutation of all four hydrogen atoms, the PES provides a faithful representation of the ab initio points, with a root mean square error of 1.8 meV or 15 cm-1. The reaction path for this exoergic reaction features an attractive and barrierless entrance channel, a submerged saddle point, a shallow H4O+ well, and a barrierless exit channel. The rate coefficients for the title reaction and kinetic isotope effect have been determined on this PES using quasi-classical trajectories, and they are in good agreement with available experimental data. It is further shown that the H2O+ rotational enhancement of reactivity observed experimentally can be traced to the submerged saddle point. Using our recently proposed Sudden Vector Projection model, we demonstrate that a rotational degree of freedom of the H2O+ reactant is strongly coupled with the reaction coordinate at this saddle point, thus unraveling the origin of the pronounced mode specificity in this reaction.

Holocene evolution of the Tonle Sap Lake: valley network infill and rates of sedimentation in Cambodia's Great Lake

NASA Astrophysics Data System (ADS)

Best, J.; Darby, S. E.; Langdon, P. G.; Hackney, C. R.; Leyland, J.; Parsons, D. R.; Aalto, R. E.; Marti, M.

2017-12-01

Tonle Sap Lake, the largest freshwater lake in SE Asia (c. 120km long and 35 km wide), is a vital ecosystem that provides 40-60% of the protein for the population of Cambodia. The lake is fed by flow from the Mekong River that causes the lake rise in level by c. 8m during monsoonal and cyclone-related floods, with drainage of the lake following the monsoon. Hydropower dam construction on the Mekong River has raised concerns as to the fragility of the Tonle Sap habitat due to any changing water levels and sedimentation rates within the lake. This paper details results of sub-bottom profiling surveys of Tonle Sap Lake in October 2014 that detailed the stratigraphy of the lake and assessed rates of infill. An Innomar Parametric Echo Sounder (PES) was used to obtain c. 250 km of sub-bottom profiles, with penetration up to 15m below the lake bed at a vertical resolution of c. 0.20m. These PES profiles were linked to cores from the north of the lake and previous literature. The PES profiles reveal a network of valleys, likely LGM, with relief up to c. 15-20m, that have been infilled by a suite of Holocene sediments. The valley surface is picked out as a strong reflector throughout the lake, and displays a series of valleys that are up to c. 15m deep and commonly 50-200m wide, although some of the largest valleys are 1.2km in width. Modelling of channel network incision during LGM conditions generates landscapes consistent with our field observations. The Tonle Sap valley network is infilled by sediments that show firstly fluvial and/or subaerial slope sedimentation, and then by extensive, parallel-bedded, lacustrine sedimentation. Lastly, the top c. 1m of sedimentation is marked by a distinct basal erosional surface that can be traced over much of the Tonle Sap Lake, and that is overlain by a series of parallel PES reflections. This upper sediment layer is interpreted to represent sedimentation in the Tonle Sap lake due to sediment suspension settling but after a period of widespread erosion that generated the extensive erosion surface. This paper will detail the characteristics and interpretation of the PES facies, their correlation to cores and estimates of sedimentation rates. Dating and PES profiles indicate that infill of the lake was complete by c. 6ka and that minimal sedimentation has occurred since then, likely due to reworking by wave resuspension.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Zhigang, E-mail: zsun@dicp.ac.cn; Yu, Dequan; Xie, Wenbo

The O + O{sub 2} isotope exchange reactions play an important role in determining the oxygen isotopic composition of a number of trace gases in the atmosphere, and their temperature dependence and kinetic isotope effects (KIEs) provide important constraints on our understanding of the origin and mechanism of these and other unusual oxygen KIEs important in the atmosphere. This work reports a quantum dynamics study of the title reactions on the newly constructed Dawes-Lolur-Li-Jiang-Guo (DLLJG) potential energy surface (PES). The thermal reaction rate coefficients of both the {sup 18}O + {sup 32}O{sub 2} and {sup 16}O + {sup 36}O{sub 2}more » reactions obtained using the DLLJG PES exhibit a clear negative temperature dependence, in sharp contrast with the positive temperature dependence obtained using the earlier modified Siebert-Schinke-Bittererova (mSSB) PES. In addition, the calculated KIE shows an improved agreement with the experiment. These results strongly support the absence of the “reef” structure in the entrance/exit channels of the DLLJG PES, which is present in the mSSB PES. The quantum dynamics results on both PESs attribute the marked KIE to strong near-threshold reactive resonances, presumably stemming from the mass differences and/or zero point energy difference between the diatomic reactant and product. The accurate characterization of the reactivity for these near-thermoneutral reactions immediately above the reaction threshold is important for correct characterization of the thermal reaction rate coefficients.« less

Micro-structure, Mechanical Properties and Dielectric Properties of Bisphenol A Allyl Compound-Bismaleimide Modified by Super-Critical Silica and Polyethersulfone Composite

NASA Astrophysics Data System (ADS)

Chen, Yufei; Wang, Botao; Li, Fangliang; Teng, Chengjun

2017-07-01

Bisphenol A allyl compound-bismaleimide (MBAE) composite modified by SCE-SiO2 and polyethersulfone (PES) resin has been prepared and researched. SCE-SiO2 was modified by super-critical ethanol and PES thermoplastic resin used as modifiers. The composite was prepared via the hot melting method. The FT-IR measurements indicated that ethanol molecular had adsorbed on the nano-SiO2 surface. SEM images showed that the composite had a multiphase structure, PES and SCE-SiO2 existed as a dispersed phase, and the interaction of the three phases affected each other, such that the bending fracture behavior transformed from brittle fracture to ductile fracture, and the modifiers of SCE-SiO2 and PES resin could improve the mechanical properties. The impact and the bending strength of the composite was 16.5 kJ/mm2 and 150.4 MPa, improved by 68.3% and 56.7% compared with those of the MBAE matrix, respectively, when the content of SCE-SiO2 was 2 wt.% and PES 5 wt.%. The dielectric constant ( ɛ) of the composites was less than 3.9 and decreased with increasing frequency, and the dielectric loss was less than 9 × 10-3 for frequencies between 102 Hz and 105 Hz. These properties could meet the requirement of insulating material.

The Cl + O3 reaction: a detailed QCT simulation of molecular beam experiments.

PubMed

Menéndez, M; Castillo, J F; Martínez-Haya, B; Aoiz, F J

2015-10-14

We have studied in detail the dynamics of the Cl + O3 reaction in the 1-56 kcal mol(-1) collision energy range using quasi-classical trajectory (QCT) calculations on a recent potential energy surface (PES) [J. F. Castillo et al., Phys. Chem. Chem. Phys., 2011, 13, 8537]. The main goal of this work has been to assess the accuracy of the PES and the reliability of the QCT method by comparison with the existing crossed molecular beam results [J. Zhang and Y. T. Lee J. Phys. Chem. A, 1997, 101, 6485]. For this purpose, we have developed a methodology that allows us to determine the experimental observables in crossed molecular beam experiments (integral and differential cross sections, recoil velocity distributions, scattering angle-recoil velocity polar maps, etc.) as continuous functions of the collision energy. Using these distributions, raw experimental data in the laboratory frame (angular distributions and time-of-flight spectra) have been simulated from first principles with the sole information on the instrumental parameters and taking into account the energy spread. A general good agreement with the experimental data has been found, thereby demonstrating the adequacy of the QCT method and the quality of the PES to describe the dynamics of this reaction at the level of resolution of the existing crossed beam experiments. Some features which are apparent in the differential cross sections have also been analysed in terms of the dynamics of the reaction and its evolution with the collision energy.

Highly Accurate Potential Energy Surface, Dipole Moment Surface, Rovibrational Energy Levels, and Infrared Line List for (32)S(16)O2 up to 8000 cm(exp -1)

NASA Technical Reports Server (NTRS)

Huang, Xinchuan; Schwenke, David W.; Lee, Timothy J.

2014-01-01

A purely ab initio potential energy surface (PES) was refined with selected (32)S(16)O2 HITRAN data. Compared to HITRAN, the root-mean-squares error (RMS) error for all J=0-80 rovibrational energy levels computed on the refined PES (denoted Ames-1) is 0.013 cm(exp -1). Combined with a CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), an infrared (IR) line list (denoted Ames-296K) has been computed at 296K and covers up to 8,000 cm(exp -1). Compared to the HITRAN and CDMS databases, the intensity agreement for most vibrational bands is better than 85-90%. Our predictions for (34)S(16)O2 band origins, higher energy (32)S(16)O2 band origins and missing (32)S(16)O2 IR bands have been verified by most recent experiments and available HITRAN data. We conclude that the Ames-1 PES is able to predict (32/34)S(16)O2 band origins below 5500 cm(exp -1) with 0.01-0.03 cm(exp -1) uncertainties, and the Ames-296K line list provides continuous, reliable and accurate IR simulations. The Ka-dependence of both line position and line intensity errors is discussed. The line list will greatly facilitate SO2 IR spectral experimental analysis, as well as elimination of SO2 lines in high-resolution astronomical observations.

PESTICIDE TRANSFER EFFICIENCY FROM HOUSEHOLD SURFACES TO FOODS

EPA Science Inventory

Application of pesticides around homes presents a potential for exposure to young children. Contaminated surfaces can be contacted by children's hands or foods which could allow transfer of pesticides. The exposures caused by these contacts are uncertain because the amount of pes...

The grasping side of post-error slowing.

PubMed

Ceccarini, Francesco; Castiello, Umberto

2018-06-07

A common finding across many speeded reaction time (RT) tasks is that people tend to respond more slowly after making an error. This phenomenon, known as post-error slowing (PES), has been traditionally hypothesized to reflect a strategic increase in response caution, aimed at preventing the occurrence of new errors. However, this interpretation of PES has been challenged on multiple fronts. Firstly, recent investigations have suggested that errors may produce a decrement in performance accuracy and that PES might occur because error processing has a detrimental effect on subsequent information processing. Secondly, previous research has been criticized because of the limited ecological validity of speeded RT tasks. In the present study, we investigated error-reactivity in the context of goal-directed actions, in order to examine the extent to which PES effects impact on realistic and complex movements. Specifically, we investigated the effect of errors on the reach to grasp movement (Experiment 1). In addition to RTs, we performed a kinematical analysis in order to explore the underlying reorganization of the movements after an error. The results of the present study showed that error reactivity strategically influences the grasping component of the action, whereas the reaching component appears to be impermeable to PES. The resistance of the reaching component to PES was confirmed in a second 'only reaching' experiment (Experiment 2). These finding supports the hypothesis that error reactivity is a flexible process whose effects on behavior also depend on the motor components involved in the action. Copyright © 2018 Elsevier B.V. All rights reserved.

PES1 regulates sensitivity of colorectal cancer cells to anticancer drugs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Wei; Qu, Like, E-mail: qulike@bjcancer.org; Meng, Lin

2013-02-15

Highlights: ► PES1 was overexpressed in diverse cancer cell lines. ► PES1-ablation enhances DNA damage response by decreasing DNA repair. ► PES1-ablation increases the sensitivity of HCT116 cells to chemotherapeutic agents. ► PES1-ablation is associated with diminished nuclear entry of RAD51. -- Abstract: PES1 (also known as Pescadillo), a nucleolar protein, was involved in biogenesis of ribosomal RNA. Up-regulation of PES1 has been documented in some human cancers, indicating that PES1 may play some crucial roles in tumorigenesis. In our previous study, it was found that silencing of PES1 resulted in decreased proliferation of colorectal cancer cells. We also noticedmore » that depletion of PES1 altered expression profiles of diverse genes. In the present study, we validated the expression changes of a subset of genotoxic stress-related genes in PES1-silenced HCT116 cells by quantitative RT-PCR. The steady and etoposide-induced phosphorylated H2AX (γ-H2AX) were higher in PES1-silenced cells than in control cells. Besides, etoposide-induced γ-H2AX persisted longer in PES1-silenced cells after removing the etoposide. Next, results of comet assay revealed decreased DNA repair after PES1-ablation. PES1-ablated cells were more sensitive to chemotherapeutic agents, which could be reversed by reconstitution with exogenous PES1. Furthermore, deletion of PES1 diminished steady and DNA damage-induced levels of nuclear RAD51. Our results uncover a potential role of PES1 in chemoresistance by regulating DNA damage response in colorectal cancer cells.« less

The molecular dimension of microbial species: 1. Ecological distinctions among, and homogeneity within, putative ecotypes of Synechococcus inhabiting the cyanobacterial mat of Mushroom Spring, Yellowstone National Park

PubMed Central

Becraft, Eric D.; Wood, Jason M.; Rusch, Douglas B.; Kühl, Michael; Jensen, Sheila I.; Bryant, Donald A.; Roberts, David W.; Cohan, Frederick M.; Ward, David M.

2015-01-01

Based on the Stable Ecotype Model, evolution leads to the divergence of ecologically distinct populations (e.g., with different niches and/or behaviors) of ecologically interchangeable membership. In this study, pyrosequencing was used to provide deep sequence coverage of Synechococcus psaA genes and transcripts over a large number of habitat types in the Mushroom Spring microbial mat. Putative ecological species [putative ecotypes (PEs)], which were predicted by an evolutionary simulation based on the Stable Ecotype Model (Ecotype Simulation), exhibited distinct distributions relative to temperature-defined positions in the effluent channel and vertical position in the upper 1 mm-thick mat layer. Importantly, in most cases variants predicted to belong to the same PE formed unique clusters relative to temperature and depth in the mat in canonical correspondence analysis, supporting the hypothesis that while the PEs are ecologically distinct, the members of each ecotype are ecologically homogeneous. PEs responded differently to experimental perturbations of temperature and light, but the genetic variation within each PE was maintained as the relative abundances of PEs changed, further indicating that each population responded as a set of ecologically interchangeable individuals. Compared to PEs that predominate deeper within the mat photic zone, the timing of transcript abundances for selected genes differed for PEs that predominate in microenvironments closer to upper surface of the mat with spatiotemporal differences in light and O2 concentration. All of these findings are consistent with the hypotheses that Synechococcus species in hot spring mats are sets of ecologically interchangeable individuals that are differently adapted, that these adaptations control their distributions, and that the resulting distributions constrain the activities of the species in space and time. PMID:26157420

[Study on spectroscopic characterization and property of PES/ micro-nano cellulose composite membrane material].

PubMed

Tang, Huan-Wei; Zhang, Li-Ping; Li, Shuai; Zhao, Guang-Jie; Qin, Zhu; Sun, Su-Qin

2010-03-01

In the present paper, the functional groups of PES/micro-nano cellulose composite membrane materials were characterized by Fourier transform infrared spectroscopy (FTIR). Also, changes in crystallinity in composite membrane materials were analyzed using X-ray diffraction (XRD). The effects of micro-nano cellulose content on hydrophilic property of composite membrane material were studied by measuring hydrophilic angle. The images of support layer structure of pure PES membrane material and composite membrane material were showed with scanning electron microscope (SEM). These results indicated that in the infrared spectrogram, the composite membrane material had characteristic peaks of both PES and micro-nano cellulose without appearance of other new characteristics peaks. It revealed that there were no new functional groups in the composite membrane material, and the level of molecular compatibility was achieved, which was based on the existence of inter-molecular hydrogen bond association between PES and micro-nano cellulose. Due to the existence of micro-nano cellulose, the crystallinity of composite membrane material was increased from 37.7% to 47.9%. The more the increase in micro-nano cellulose mass fraction, the better the van de Waal force and hydrogen bond force between composite membrane material and water were enhanced. The hydrophilic angle of composite membrane material was decreased from 55.8 degrees to 45.8 degrees and the surface energy was raised from 113.7 to 123.5 mN x m(-2). Consequently, the hydrophilic property of composite membrane material was improved. The number of pores in the support layer of composite membrane material was lager than that of pure PES membrane. Apparently, pores were more uniformly distributed.

A new ab initio potential energy surface for the NH-He complex

NASA Astrophysics Data System (ADS)

Ramachandran, R.; Kłos, J.; Lique, F.

2018-02-01

We present a new three-dimensional potential energy surface (PES) for the NH(X3Σ-)-He van der Waals system, which explicitly takes into account the NH vibrational motion. The NH-He PES was obtained using the open-shell single- and double-excitation coupled cluster approach with non-iterative perturbational treatment of triple excitations. The augmented correlation-consistent aug-cc-pVXZ (X = Q, 5, 6) basis sets were employed, and the energies obtained were then extrapolated to the complete basis set limit. Using this new PES, we have studied the spectroscopy of the NH-He complex and we have determined a new rotational constant that agrees well with the available experimental data. Collisional excitation of NH(X3Σ-) by He was also studied at the close-coupling level. Calculations of the collisional excitation cross sections of the fine-structure levels of NH by He were performed for energies up to 3500 cm-1, which yield, after thermal average, rate coefficients up to 350 K. The calculated rate coefficients are compared with available experimental measurements at room temperature, and a reasonably good agreement is found between experimental and theoretical data.

CCSD(T) potential energy and induced dipole surfaces for N2–H2(D2): retrieval of the collision-induced absorption integrated intensities in the regions of the fundamental and first overtone vibrational transitions.

PubMed

Buryak, Ilya; Lokshtanov, Sergei; Vigasin, Andrey

2012-09-21

The present work aims at ab initio characterization of the integrated intensity temperature variation of collision-induced absorption (CIA) in N(2)-H(2)(D(2)). Global fits of potential energy surface (PES) and induced dipole moment surface (IDS) were made on the basis of CCSD(T) (coupled cluster with single and double and perturbative triple excitations) calculations with aug-cc-pV(T,Q)Z basis sets. Basis set superposition error correction and extrapolation to complete basis set (CBS) limit techniques were applied to both energy and dipole moment. Classical second cross virial coefficient calculations accounting for the first quantum correction were employed to prove the quality of the obtained PES. The CIA temperature dependence was found in satisfactory agreement with available experimental data.

Enzymatically oxidized phospholipids restore thrombin generation in coagulation factor deficiencies.

PubMed

Slatter, David A; Percy, Charles L; Allen-Redpath, Keith; Gajsiewicz, Joshua M; Brooks, Nick J; Clayton, Aled; Tyrrell, Victoria J; Rosas, Marcela; Lauder, Sarah N; Watson, Andrew; Dul, Maria; Garcia-Diaz, Yoel; Aldrovandi, Maceler; Heurich, Meike; Hall, Judith; Morrissey, James H; Lacroix-Desmazes, Sebastien; Delignat, Sandrine; Jenkins, P Vincent; Collins, Peter W; O'Donnell, Valerie B

2018-03-22

Hemostatic defects are treated using coagulation factors; however, clot formation also requires a procoagulant phospholipid (PL) surface. Here, we show that innate immune cell-derived enzymatically oxidized phospholipids (eoxPL) termed hydroxyeicosatetraenoic acid-phospholipids (HETE-PLs) restore hemostasis in human and murine conditions of pathological bleeding. HETE-PLs abolished blood loss in murine hemophilia A and enhanced coagulation in factor VIII- (FVIII-), FIX-, and FX-deficient human plasma . HETE-PLs were decreased in platelets from patients after cardiopulmonary bypass (CPB). To explore molecular mechanisms, the ability of eoxPL to stimulate individual isolated coagulation factor/cofactor complexes was tested in vitro. Extrinsic tenase (FVIIa/tissue factor [TF]), intrinsic tenase (FVIIIa/FIXa), and prothrombinase (FVa/FXa) all were enhanced by both HETE-PEs and HETE-PCs, suggesting a common mechanism involving the fatty acid moiety. In plasma, 9-, 15-, and 12-HETE-PLs were more effective than 5-, 11-, or 8-HETE-PLs, indicating positional isomer specificity. Coagulation was enhanced at lower lipid/factor ratios, consistent with a more concentrated area for protein binding. Surface plasmon resonance confirmed binding of FII and FX to HETE-PEs. HETE-PEs increased membrane curvature and thickness, but not surface charge or homogeneity, possibly suggesting increased accessibility to cations/factors. In summary, innate immune-derived eoxPL enhance calcium-dependent coagulation factor function, and their potential utility in bleeding disorders is proposed.

Enzymatically oxidized phospholipids restore thrombin generation in coagulation factor deficiencies

PubMed Central

Slatter, David A.; Percy, Charles L.; Allen-Redpath, Keith; Gajsiewicz, Joshua M.; Brooks, Nick J.; Tyrrell, Victoria J.; Lauder, Sarah N.; Watson, Andrew; Dul, Maria; Garcia-Diaz, Yoel; Aldrovandi, Maceler; Heurich, Meike; Hall, Judith; Lacroix-Desmazes, Sebastien; Delignat, Sandrine; Jenkins, P. Vincent; Collins, Peter W.; O’Donnell, Valerie B.

2018-01-01

Hemostatic defects are treated using coagulation factors; however, clot formation also requires a procoagulant phospholipid (PL) surface. Here, we show that innate immune cell–derived enzymatically oxidized phospholipids (eoxPL) termed hydroxyeicosatetraenoic acid–phospholipids (HETE-PLs) restore hemostasis in human and murine conditions of pathological bleeding. HETE-PLs abolished blood loss in murine hemophilia A and enhanced coagulation in factor VIII- (FVIII-), FIX-, and FX-deficient human plasma . HETE-PLs were decreased in platelets from patients after cardiopulmonary bypass (CPB). To explore molecular mechanisms, the ability of eoxPL to stimulate individual isolated coagulation factor/cofactor complexes was tested in vitro. Extrinsic tenase (FVIIa/tissue factor [TF]), intrinsic tenase (FVIIIa/FIXa), and prothrombinase (FVa/FXa) all were enhanced by both HETE-PEs and HETE-PCs, suggesting a common mechanism involving the fatty acid moiety. In plasma, 9-, 15-, and 12-HETE-PLs were more effective than 5-, 11-, or 8-HETE-PLs, indicating positional isomer specificity. Coagulation was enhanced at lower lipid/factor ratios, consistent with a more concentrated area for protein binding. Surface plasmon resonance confirmed binding of FII and FX to HETE-PEs. HETE-PEs increased membrane curvature and thickness, but not surface charge or homogeneity, possibly suggesting increased accessibility to cations/factors. In summary, innate immune-derived eoxPL enhance calcium-dependent coagulation factor function, and their potential utility in bleeding disorders is proposed. PMID:29563336

Nucleophilic substitution at silicon (SN2@Si) via a central reaction barrier.

PubMed

Bento, A Patrícia; Bickelhaupt, F Matthias

2007-03-16

It is textbook knowledge that nucleophilic substitution at carbon (SN2@C) proceeds via a central reaction barrier which disappears in the corresponding nucleophilic substitution reaction at silicon (SN2@Si). Here, we address the question why the central barrier disappears from SN2@C to SN2@Si despite the fact that these processes are isostructural and isoelectronic. To this end, we have explored and analyzed the potential energy surfaces (PES) of various Cl-+CR3Cl (R=H, CH3) and Cl-+SiR3Cl model reactions (R=H, CH3, C2H5, and OCH3). Our results show that the nature of the SN2 reaction barrier is in essence steric, but that it can be modulated by electronic factors. Thus, simply by increasing the steric demand of the substituents R around the silicon atom, the SN2@Si mechanism changes from its regular single-well PES (with a stable intermediate transition complex, TC), via a triple-well PES (with a pre- and a post-TS before and after the central TC), to a double-well PES (with a TS; R=OCH3), which is normally encountered for SN2@C reactions.

Polyester polymer alloy as a high-performance membrane.

PubMed

Igoshi, Tadaaki; Tomisawa, Narumi; Hori, Yoshinori; Jinbo, Yoichi

2011-01-01

Polyester polymer alloy (PEPA) membrane is developed as a synthetic polymermembrane. It consists of two polymers - polyethersulfone (PES) and polyarylate (PAR).The pore size in membrane can be controlled by a blend ratio of PES and PAR. One unique characteristic is that PEPA membrane has three layers of a skin layer on the inner surface, a porous layer in the membrane, and a skin layer on the outer surface, respectively. The permeability of water and substances is controlled by the skin layer on the inner surface. PEPA membrane dialyzer can be adequately considered as a high-performance dialyzer. Furthermore, the skin layer on the outer surface can block endotoxin from the dialysis fluid side. PEPA membrane can therefore be used as an endotoxin-retentive filter. The other unique characteristic is that each amount of albumin loss or β2-microglobulin removal can be controlled by an additive amount of polyvinylpyrrolidone. This means that the PEPA dialyzer can be clinically used to meet the conditions of the patient. Copyright © 2011 S. Karger AG, Basel.

Fundamental and Applied Studies of Polymer Membranes

NASA Astrophysics Data System (ADS)

Imbrogno, Joseph

Four major areas have been studied in this research: 1) synthesizing novel monomers, e.g. chiral monomers, to produce new types of functionalized membranes for the biotechnology and pharmaceutical industries, 2) hydrophobic brush membranes for desalinating brackish water, sea water, and separating organics, 3) fundamental studies of water interactions at surfaces using sum frequency generation (SFG), and 4) discovering new surface chemistries that will control the growth and differentiation of stem cells. We have developed a novel synthesis method in order to increase the breadth of our high throughput screening library. This library was generated using maleimide chemistry to react a common methacrylate linker with a variety of different functions groups (R groups) in order to form new monomers that were grafted from the surface of PES ultrafiltration membranes. From this work, we discovered that the chirality of a membrane can affect performance when separating chiral feed streams. This effect was observed when filtering bovine serum albumin (BSA) and ovalbumin in a high salt phosphate buffered saline (PBS, 150 mM salt). The Phe grafted membranes showed a large difference in performance when filtering BSA with selectivity of 1.13 and 1.00 for (S) and (R) Phe, respectively. However, when filtering ovalbumin, the (S) and (R) modified surfaces showed selectivity of 2.06 and 2.31, respectively. The higher selectivity enantiomer switched for the two different proteins. Permeability when filtering BSA was 3.06 LMH kPa-1 and 4.31 LMH kPa -1 for (S)- and (R)- Phe, respectively, and 2.65 LMH kPa -1 and 2.10 LMH kPa-1 when filtering ovalbumin for (S)- and (R)- Phe, respectively. Additionally, these effects were no longer present when using a low salt phosphate buffer (PB, 10 mM salt). Since, to our knowledge, membrane chirality is not considered in current industrial systems, this discovery could have a large impact on the pharmaceutical and biotechnology industries. We have developed hydrophobic brush membranes that were able to selectively separate valuable organics (isobutanol) from water, while rejecting other undesirable species, such as enzymes, using pervaporation (PV). These membranes (grafted from nanofiltration (NF) support membranes) had a selectivity ˜1.5x higher than the current industrial standard, polydimethylsiloxane (PDMS), with alpha = 10.1 +/- 0.9 for our brush membranes and alpha = 6.7 +/- 0.1 for PDMS membranes. Since the mechanism of pervaporation is based on the solution diffusion (SD) model, these membranes may be used to desalinate water or fractionate gases since they are also based on the SD mechanism. We have discovered that hydrophobic brush membranes are able to reject monovalent salt ions. This type of membrane is analogous to carbon nanotubes (CNTs), which are believed to have extremely high water fluxes through them due to near frictionless flow caused by a lack of hydrogen bonding. Using these brush membranes we were able to achieve 42% monovalent (NaCl) salt rejection of simulated seawater (32,000 ppm salt). These membranes are easier to scale-up than current composite membranes produced using interfacial polymerization. We have been using SFG to study interfacial water on membrane surfaces. We believe that water interactions with the membrane surface and with the feed species, e.g. proteins, play a critical role during the fouling process. Relevant buffers, such as phosphate buffered saline (PBS) and phosphate buffer, contain ions that are known to restructure water at interfaces. Sum frequency generation spectroscopy (SFG) was used to characterize interfacial water structure at poly(ether sulfone) (PES) thin films in the presence of 0.01 M phosphate buffer (low salt) and 0.01 M phosphate buffered saline (high salt). Three model surfaces were studied: unmodified PES, hydrophobic alkane (C18) modified PES, and poly(ethylene glycol) (PEG) modified PES. In the presence of the low salt phosphate buffer (10 mM salt), phosphate anions were excluded from the PEG-modified PES film. This led to a charge separation between the phosphate anions and sodium cations, creating a surface potential which strongly ordered water molecules into the bulk. When using high salt PBS (138 mM salt) the sodium chloride ions screened this charge and reduced water ordering. Interestingly, this effect was the greatest for the PEG modified surface, with minor or no effects observed for the C18 modified PES and unmodified PES, respectively. Using our high throughput screening platform, we were able to determine that (N-[3-(dimethylamino)propyl] methacrylamide), DMAPMA, supported strong attachment and long-term self-renewal of mouse embryonic stem (ES) cells while preventing differentiation (maintaining pluripotency). After developing this platform, it was used to screen for a surface that could instead induce differentiation of bovine and human retinal pigment epithelium (RPE) cells while promoting cell growth. Several PEG based surfaces were able to induce cobblestone morphology of the RPE cells, which is indicative of differentiation. (Abstract shortened by UMI.).

MCTDH on-the-fly: Efficient grid-based quantum dynamics without pre-computed potential energy surfaces

NASA Astrophysics Data System (ADS)

Richings, Gareth W.; Habershon, Scott

2018-04-01

We present significant algorithmic improvements to a recently proposed direct quantum dynamics method, based upon combining well established grid-based quantum dynamics approaches and expansions of the potential energy operator in terms of a weighted sum of Gaussian functions. Specifically, using a sum of low-dimensional Gaussian functions to represent the potential energy surface (PES), combined with a secondary fitting of the PES using singular value decomposition, we show how standard grid-based quantum dynamics methods can be dramatically accelerated without loss of accuracy. This is demonstrated by on-the-fly simulations (using both standard grid-based methods and multi-configuration time-dependent Hartree) of both proton transfer on the electronic ground state of salicylaldimine and the non-adiabatic dynamics of pyrazine.

Influence of nanoparticles on filterability of fruit-juice industry wastewater using submerged membrane bioreactor.

PubMed

Demirkol, Guler Turkoglu; Dizge, Nadir; Acar, Turkan Ormanci; Salmanli, Oyku Mutlu; Tufekci, Nese

2017-07-01

In this study, polyethersulfone (PES) ultrafiltration membrane surface was modified with nano-sized zinc oxide (nZnO) and silver (nAg) to improve the membrane filterability of the mixed liquor and used to treat fruit-juice industry wastewater in a submerged membrane bioreactor (MBR). The nAg was synthesized using three different methods. In the first method, named as nAg-M1, PES membrane was placed on the membrane module and nAg solution was passed through the membrane for 24 h at 25 ± 1 °C. In the second method, named as nAg-M2, PES membrane was placed in a glass container and it was shaken for 24 h at 150 rpm at 25 ± 1 °C. In the third method, named as nAg-M3, Ag nanoparticles were loaded onto PES membrane in L-ascorbic acid solution (0.1 mol/L) at pH 2 for 24 h at 150 rpm at 25 ± 1 °C. For the preparation of nZnO coated membrane, nZnO nanoparticles solution was passed through the membrane for 24 h at 25 ± 1 °C. Anti-fouling performance of pristine and coated membranes was examined using the submerged MBR. The results showed that nZnO and nAg-M3 membranes showed lower flux decline compared with pristine membrane. Moreover, pristine and coated PES membranes were characterized using a permeation test, contact angle goniometer, and scanning electron microscopy.

The present and future use of physician extenders in general surgery training programs: one response to the 80-hour work week.

PubMed

Pezzi, Christopher; Leibrandt, Thomas; Suryadevara, Sree; Heller, Janice K; Hurley-Martonik, Donna; Kukora, John S

2009-04-01

The aim of this study was to assess the use of physician extenders (PEs) in general surgery residency programs. We surveyed the program directors in surgery for the number of chief residents, PEs on general surgery services, PE duties, whether PEs were hired in response to Accreditation Council for Graduate Medical Education work-hour restrictions, plans to hire additional PEs, and program type. Data were analyzed using the Student's t-test; p values are two-tailed and considered significant if <0.05. There were 163 programs (65%) that responded, (87 university, 70 nonuniversity, and 6 military programs), with a total of 689 graduating chief residents per year. One hundred sixty programs use 840 PEs (median, 3.5 PEs per program; mean, 5.3 PEs per program, 2 PEs per chief resident). One hundred twenty-seven programs (79%) use at least 1 PE (range 1 to 50 PEs); 93 programs (57%) hired 513 (61%) PEs in response to work-hour restrictions. Before 2003, the mean number of PEs per program was 2.0; after 2003, there were 5.3 per program (p=0.0001). Most common uses of PEs included taking histories and physicals (84%), seeing consults (58%), first-assisting (52%), and seeing patients in the emergency department (47%). Forty-seven of 162 (29%) programs plan to hire more PEs in the next 3 years, 76 programs (47%) would like to, but are unsure of funding; 23 programs (14%) are not planning to increase the total, and 16 programs (10%) are unsure. With available funding, 431 additional PEs may be hired in the next 3 years, for a total of 1,271 PEs in 163 programs, or an average of 7.8 PEs per program and 1.8 PEs per chief resident. PEs have been hired in large numbers to assist on general surgery teaching services, with most hired in response to Accreditation Council for Graduate Medical Education work-hour restrictions, and most of their duties are intended to aid resident education. Almost 80% of programs currently use PEs; 76% would like to hire more. Currently 1.2 PEs are used per graduating chief resident; this could increase to 1.8 PEs per chief resident in the next 3 years.

Dielectric Properties of Polyether Sulfone/Bismaleimide Resin Composite Based on Nanolumina Modified by Super-Critical Ethanol

NASA Astrophysics Data System (ADS)

Chen, Yufei; Li, Zhichao; Teng, Chengjun; Li, Fangliang; Han, Yang

2016-11-01

Nano-alumina was chemically modified with super-critical ethanol enabling a surface active coating. Modified nano-alumina was incorporated in polymer blends based on thermoplastic polyether sulfone and thermosetting bismaleimide resin to produce novel nanocomposites designated as SCE-Al2O3/PES-MBAE. In the SCE-Al2O3/PES-MBAE nano-composites, the matrix was originally formed from 4,4'-diamino diphenyl methane bismaleimide (MBMI) using the diluents of 3,3'-diallyl bisphenol A (BBA) and bisphenol-A diallyl ether (BBE), while polyether sulfone (PES) was used as toughening agent along with super-critically modified nano-alumina (SCE-Al2O3) as filler material. The content of SCE-Al2O3 was varied from 0 wt.% to 6 wt.%. The nano-composites were characterized for their morphological, spectroscopic and dielectric properties. Fourier transform infrared spectroscopy (FT-IR) indicated that ethanol molecules had adhered to the surface of the nano-Al2O3 in super-critical state. A reaction between MBMI and allyl compound occurred and SCE-Al2O3 was doped into the polymer matrix. Volume resistivity of the composite initially increased and then decreased. The modification due to SCE-Al2O3 could overcome the undesirable impact of PES by using a bare minimum level of SCE-Al2O3. The dielectric constant ( ɛ) and dielectric loss (tan δ) as in the case of volume resistivity were initially increased and then decreased with the content of SCE-Al2O3 in the composite. The dielectric constant, dielectric loss and dielectric strength of SCE-Al2O3 (4 wt.%)/PES (5 wt.%)-MBAE nano-composite were 3.53 (100 Hz), 1.52 × 10-3 (100 Hz) and 15.66 kV/mm, respectively, which indicated that the dielectric properties of the composite fulfilled the basic requirements of electrical and insulating material. It was evident from the morphological analysis that the SCE-Al2O3 was evenly dispersed at the nanoscale; for example, the size of SCE-Al2O3 in SCE-Al2O3 (4 wt.%)/PES (5 wt.%)-MBAE measured less than 50 nm.

PES-51

EPA Pesticide Factsheets

Technical product bulletin: this miscellaneous oil spill control agent comes already mixed and ready for use in cleanups. Through various application methods, it is effective in shoreline and surface treatment, tank cleaning, and equipment decontamination.

The influence of observers’ sex on attention-demanding performance depends on performers’ sex

PubMed Central

Wang, Lijun; Tan, Jinfeng; Chen, Jiangtao; Chen, Antao

2015-01-01

Post-error slowing (PES) indicates the slower responses after errors than after correct responses. Prior studies mainly focus on how the observation errors influence one own’s performance, there is no study investigating how other’s monitoring influence one own’s performance. Additionally, the issue that whether social context influences the PES effect differently for females and males is still unclear. To address aforementioned issues, we required the participants to interact with a same-sex or opposite-sex partner to complete a color flanker task together (they sat next to each other, Experiment 1). One was the performer (perform the flanker task), and the other was the observer (monitor the error responses of performer). They alternated their roles in two successive blocks. To further verify the role of the interaction context, a control experiment was conducted in the individual context (Experiment 2). The results revealed that (1) larger PES effect was observed in females than in males in the interaction context; (2) the sex difference of PES effect mainly benefited from the opposite-sex interaction; (3) larger PES effect was observed in the interaction context than in the individual context; (4) females’ performance was influenced after an interaction with a same-sex or opposite-sex partner, whereas males’ performance was merely influenced after an interaction with an opposite-sex partner. Taken together, these findings may suggest that (1) interaction context modulates the PES effect differently for females and males; (2) females are more susceptible to social information and hence more effective to adjust the post-error behaviors. PMID:26379574

Experimental and theoretical study of rotationally inelastic diffraction of H2(D2) from methyl-terminated Si(111)

NASA Astrophysics Data System (ADS)

Nihill, Kevin J.; Hund, Zachary M.; Muzas, Alberto; Díaz, Cristina; del Cueto, Marcos; Frankcombe, Terry; Plymale, Noah T.; Lewis, Nathan S.; Martín, Fernando; Sibener, S. J.

2016-08-01

Fundamental details concerning the interaction between H2 and CH3-Si(111) have been elucidated by the combination of diffractive scattering experiments and electronic structure and scattering calculations. Rotationally inelastic diffraction (RID) of H2 and D2 from this model hydrocarbon-decorated semiconductor interface has been confirmed for the first time via both time-of-flight and diffraction measurements, with modest j = 0 → 2 RID intensities for H2 compared to the strong RID features observed for D2 over a large range of kinematic scattering conditions along two high-symmetry azimuthal directions. The Debye-Waller model was applied to the thermal attenuation of diffraction peaks, allowing for precise determination of the RID probabilities by accounting for incoherent motion of the CH3-Si(111) surface atoms. The probabilities of rotationally inelastic diffraction of H2 and D2 have been quantitatively evaluated as a function of beam energy and scattering angle, and have been compared with complementary electronic structure and scattering calculations to provide insight into the interaction potential between H2 (D2) and hence the surface charge density distribution. Specifically, a six-dimensional potential energy surface (PES), describing the electronic structure of the H2(D2)/CH3-Si(111) system, has been computed based on interpolation of density functional theory energies. Quantum and classical dynamics simulations have allowed for an assessment of the accuracy of the PES, and subsequently for identification of the features of the PES that serve as classical turning points. A close scrutiny of the PES reveals the highly anisotropic character of the interaction potential at these turning points. This combination of experiment and theory provides new and important details about the interaction of H2 with a hybrid organic-semiconductor interface, which can be used to further investigate energy flow in technologically relevant systems.

PES Holdings, LLC, et. al. Bankruptcy Renewable Fuel Standard Settlement

EPA Pesticide Factsheets

PES Holdings, LLC, North Yard Financing, LLC, North Yard GP, LLC, North Yard Logistics, L.P., PES Administrative Services, LLC, PES Logistics GP, LLC, PES Logistics Partners, L.P., Philadelphia Energy Solutions Refining and Marketing LLC (PESRM),

Polyethersulfone/polyacrylonitrile blended ultrafiltration membranes: preparation, morphology and filtration properties.

PubMed

Pasaoglu, Mehmet Emin; Guclu, Serkan; Koyuncu, Ismail

Polyethersulfone (PES)/polyacrylonitrile (PAN) membranes have been paid attention among membrane research subjects. However, very few studies are included in the literature. In our study, asymmetric ultrafiltration (UF) membranes were prepared from blends of PES/PAN with phase inversion method using water as coagulation bath. Polyvinylpyrrolidone (PVP) with Mw of 10,000 Da was used as pore former agent. N,N-dimethylformamide was used as solvent. The effects of different percentage of PVP and PES/PAN composition on morphology and water filtration properties were investigated. Membrane performances were examined using pure water and lake water filtration studies. Performances of pure water were less with the addition of PAN into the PES polymer casting solutions. However, long-term water filtration tests showed that PES/PAN blend membranes anti-fouling properties were much higher than the neat PES membranes. The contact angles of PES/PAN membranes were lower than neat PES membranes because of PAN addition in PES polymer casting solutions. Furthermore, it was found that PES/PAN blend UF membranes' dynamic mechanical analysis properties in terms of Young's modules were less than neat PES membrane because of decreasing amount of PES polymer.

Collective communications apparatus and method for parallel systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knies, Allan D.; Keppel, David Pardo; Woo, Dong Hyuk

A collective communication apparatus and method for parallel computing systems. For example, one embodiment of an apparatus comprises a plurality of processor elements (PEs); collective interconnect logic to dynamically form a virtual collective interconnect (VCI) between the PEs at runtime without global communication among all of the PEs, the VCI defining a logical topology between the PEs in which each PE is directly communicatively coupled to a only a subset of the remaining PEs; and execution logic to execute collective operations across the PEs, wherein one or more of the PEs receive first results from a first portion of themore » subset of the remaining PEs, perform a portion of the collective operations, and provide second results to a second portion of the subset of the remaining PEs.« less

Topographies and dynamics on multidimensional potential energy surfaces

NASA Astrophysics Data System (ADS)

Ball, Keith Douglas

The stochastic master equation is a valuable tool for elucidating potential energy surface (PES) details that govern structural relaxation in clusters, bulk systems, and protein folding. This work develops a comprehensive framework for studying non-equilibrium relaxation dynamics using the master equation. Since our master equations depend upon accurate partition function models for use in Rice-Ramsperger-Kassel-Marcus (RRK(M) transition state theory, this work introduces several such models employing various harmonic and anharmonic approximations and compares their predicted equilibrium population distributions with those determined from molecular dynamics. This comparison is performed for the fully-delineated surfaces (KCl)5 and Ar9 to evaluate model performance for potential surfaces with long- and short-range interactions, respectively. For each system, several models perform better than a simple harmonic approximation. While no model gives acceptable results for all minima, and optimal modeling strategies differ for (KCl)5 and Ar9, a particular one-parameter model gives the best agreement with simulation for both systems. We then construct master equations from these models and compare their isothermal relaxation predictions for (KCl)5 and Ar9 with molecular dynamics simulations. This is the first comprehensive test of the kinetic performance of partition function models of its kind. Our results show that accurate modeling of transition-state partition functions is more important for (KCl)5 than for Ar9 in reproducing simulation results, due to a marked stiffening anharmonicity in the transition-state normal modes of (KCl)5. For both systems, several models yield qualitative agreement with simulation over a large temperature range. To examine the robustness of the master equation when applied to larger systems, for which full topographical descriptions would be either impossible or infeasible, we compute relaxation predictions for Ar11 using a master equation constructed from data representing the full PES, and compare these predictions to those of reduced master equations based on statistical samples of the full PES. We introduce a sampling method which generates random, Boltzmann-weighted, energetically 'downhill' sequences. The study reveals that, at moderate temperatures, the slowest relaxation timescale converges as the number of sequences in a sample grows to ~1000. Furthermore, the asymptotic timescale is comparable to the full-PES value.

Defining an optimal surface chemistry for pluripotent stem cell culture in 2D and 3D

NASA Astrophysics Data System (ADS)

Zonca, Michael R., Jr.

Surface chemistry is critical for growing pluripotent stem cells in an undifferentiated state. There is great potential to engineer the surface chemistry at the nanoscale level to regulate stem cell adhesion. However, the challenge is to identify the optimal surface chemistry of the substrata for ES cell attachment and maintenance. Using a high-throughput polymerization and screening platform, a chemically defined, synthetic polymer grafted coating that supports strong attachment and high expansion capacity of pluripotent stem cells has been discovered using mouse embryonic stem (ES) cells as a model system. This optimal substrate, N-[3-(Dimethylamino)propyl] methacrylamide (DMAPMA) that is grafted on 2D synthetic poly(ether sulfone) (PES) membrane, sustains the self-renewal of ES cells (up to 7 passages). DMAPMA supports cell attachment of ES cells through integrin beta1 in a RGD-independent manner and is similar to another recently reported polymer surface. Next, DMAPMA has been able to be transferred to 3D by grafting to synthetic, polymeric, PES fibrous matrices through both photo-induced and plasma-induced polymerization. These 3D modified fibers exhibited higher cell proliferation and greater expression of pluripotency markers of mouse ES cells than 2D PES membranes. Our results indicated that desirable surfaces in 2D can be scaled to 3D and that both surface chemistry and structural dimension strongly influence the growth and differentiation of pluripotent stem cells. Lastly, the feasibility of incorporating DMAPMA into a widely used natural polymer, alginate, has been tested. Novel adhesive alginate hydrogels have been successfully synthesized by either direct polymerization of DMAPMA and methacrylic acid blended with alginate, or photo-induced DMAPMA polymerization on alginate nanofibrous hydrogels. In particular, DMAPMA-coated alginate hydrogels support strong ES cell attachment, exhibiting a concentration dependency of DMAPMA. This research provides a new avenue for stem cell culture and maintenance using an optimal organic-based chemistry.

Kinetic or Dynamic Control on a Bifurcating Potential Energy Surface? An Experimental and DFT Study of Gold-Catalyzed Ring Expansion and Spirocyclization of 2-Propargyl-β-tetrahydrocarbolines.

PubMed

Zhang, Lei; Wang, Yi; Yao, Zhu-Jun; Wang, Shaozhong; Yu, Zhi-Xiang

2015-10-21

In classical transition state theory, a transition state is connected to its reactant(s) and product(s). Recently, chemists found that reaction pathways may bifurcate after a transition state, leading to two or more sets of products. The product distribution for such a reaction containing a bifurcating potential energy surface (bPES) is usually determined by the shape of the bPES and dynamic factors. However, if the bPES leads to two intermediates (other than two products), which then undergo further transformations to give different final products, what factors control the selectivity is still not fully examined. This missing link in transition state theory is founded in the present study. Aiming to develop new methods for the synthesis of azocinoindole derivatives, we found that 2-propargyl-β-tetrahydrocarbolines can undergo ring expansion and spirocyclization under gold catalysis. DFT study revealed that the reaction starts with the intramolecular cyclization of the gold-activated 2-propargyl-β-tetrahydrocarboline with a bPES. The cyclization intermediates can not only interconvert into each other via a [1,5]-alkenyl shift, but also undergo ring expansion (through fragmentation/protodeauration mechanism) or spirocyclization (through deprotonation/protodeauration mechanism). Detailed analysis of the complex PESs for substrates with different substituents indicated that the reaction selectivity is under dynamic control if the interconversion of the intermediates is slower than the ring expansion and spirocyclization processes. Otherwise, the chemical outcome is under typical kinetic control and determined by the relative preference of ring expansion versus spirocyclization pathways. The present study may enrich chemist's understanding of the determinants for selectivities on bPESs.

Torsion-wagging tunneling and vibrational states in hydrazine determined from its ab initio potential energy surface

NASA Astrophysics Data System (ADS)

Łodyga, Wiesław; Makarewicz, Jan

2012-05-01

Geometries, anharmonic vibrations, and torsion-wagging (TW) multiplets of hydrazine and its deuterated species are studied using high-level ab initio methods employing the second-order Møller-Plesset perturbation theory (MP2) as well as the coupled cluster singles and doubles model including connected triple corrections, CCSD(T), in conjunction with extended basis sets containing diffuse and core functions. To describe the splitting patterns caused by tunneling in TW states, the 3D potential energy surface (PES) for the large-amplitude TW modes is constructed. Stationary points in the 3D PES, including equivalent local minima and saddle points are characterized. Using this 3D PES, a flexible Hamiltonian is built numerically and then employed to solve the vibrational problem for TW coupled motion. The calculated ground state rav structure is expected to be more reliable than the experimental one that has been determined using a simplified structural model. The calculated fundamental frequencies allowed resolution of the assignment problems discussed earlier in the literature. The determined energy barriers, including the contributions from the small-amplitude vibrations, to the tunneling of the symmetric and antisymmetric wagging mode of 1997 cm-1 and 3454 cm-1, respectively, are in reasonable agreement with the empirical estimates of 2072 cm-1 and 3312 cm-1, respectively [W. Łodyga et al. J. Mol. Spectrosc. 183, 374 (1997), 10.1006/jmsp.1997.7271]. However, the empirical torsion barrier of 934 cm-1 appears to be overestimated. The ab initio calculations yield two torsion barriers: cis and trans of 744 cm-1 and 2706 cm-1, respectively. The multiplets of the excited torsion states are predicted from the refined 3D PES.

Glassy nature and glass-to-crystal transition in the binary metallic glass CuZr

NASA Astrophysics Data System (ADS)

Wei, Zi-Yang; Shang, Cheng; Zhang, Xiao-Jie; Liu, Zhi-Pan

2017-06-01

The prediction for the stability of glassy material is a key challenge in physical science. Here, we report a theoretical framework to predict the glass stability based on stochastic surface walking global optimization and reaction pathway sampling. This is demonstrated by revealing for the first time the global potential energy surface (PES) of two systems, CuZr binary metallic glass and nonglassy pure Cu systems, and establishing the lowest energy pathways linking glassy/amorphous structures with crystalline structures. The CuZr system has a significant number of glassy structures on PES that are ˜0.045 eV /atom above the crystal structure. Two clear trends are identified from global PES in the glass-to-crystal transition of the CuZr system: (i) the local Zr-Cu coordination (nearest neighbor) increases, and (ii) the local Zr bonding environment becomes homogeneous. This allows us to introduce quantitative structural and energetics conditions to distinguish the glassy structures from the crystalline structures. Because of the local Zr-Cu exchange in the glass-to-crystal transition, a high reaction barrier (>0.048 eV /atom ) is present to separate the glassy structures and the crystals in CuZr. By contrast, the Cu system, although it does possess amorphous structures that appear at much higher energy (˜0.075 eV /atom ) with respect to the crystal structure, has very low reaction barriers for the crystallization of amorphous structures, i.e. <0.011 eV /atom . The quantitative data on PES now available from global optimization techniques deepens our understanding on the microscopic nature of glassy material and might eventually facilitate the design of stable glassy materials.

A new potential energy surface of the OH2+ system and state-to-state quantum dynamics studies of the O+ + H2 reaction.

PubMed

Li, Wentao; Yuan, Jiuchuang; Yuan, Meiling; Zhang, Yong; Yao, Minghai; Sun, Zhigang

2018-01-03

A new global potential energy surface (PES) of the O + + H 2 system was constructed with the permutation invariant polynomial neural network method, using about 63 000 ab initio points, which were calculated by employing the multi-reference configuration interaction method with aug-cc-pVTZ and aug-cc-pVQZ basis sets. For improving the accuracy of the PES, the basis set was extrapolated to the complete basis set limit by the two-point extrapolation method. The root mean square error of fitting was only 5.28 × 10 -3 eV. The spectroscopic constants of the diatomic molecules were calculated and compared with previous theoretical and experimental results, which suggests that the present results agree well with the experiment. On the newly constructed PES, reaction dynamics studies were performed using the time-dependent wave packet method. The calculated integral cross sections (ICSs) were compared with the available theoretical and experimental results, where a good agreement with the experimental data was seen. Significant forward and backward scatterings were observed in the whole collision energy region studied. At the same time, the differential cross sections biased the forward scattering, especially at higher collision energies.

An ab initio potential energy surface for the formic acid dimer: zero-point energy, selected anharmonic fundamental energies, and ground-state tunneling splitting calculated in relaxed 1-4-mode subspaces.

PubMed

Qu, Chen; Bowman, Joel M

2016-09-14

We report a full-dimensional, permutationally invariant potential energy surface (PES) for the cyclic formic acid dimer. This PES is a least-squares fit to 13475 CCSD(T)-F12a/haTZ (VTZ for H and aVTZ for C and O) energies. The energy-weighted, root-mean-square fitting error is 11 cm -1 and the barrier for the double-proton transfer on the PES is 2848 cm -1 , in good agreement with the directly-calculated ab initio value of 2853 cm -1 . The zero-point vibrational energy of 15 337 ± 7 cm -1 is obtained from diffusion Monte Carlo calculations. Energies of fundamentals of fifteen modes are calculated using the vibrational self-consistent field and virtual-state configuration interaction method. The ground-state tunneling splitting is computed using a reduced-dimensional Hamiltonian with relaxed potentials. The highest-level, four-mode coupled calculation gives a tunneling splitting of 0.037 cm -1 , which is roughly twice the experimental value. The tunneling splittings of (DCOOH) 2 and (DCOOD) 2 from one to three mode calculations are, as expected, smaller than that for (HCOOH) 2 and consistent with experiment.

Synergistic effect of Chitosan-Zinc Oxide Hybrid Nanoparticles on antibiofouling and water disinfection of mixed matrix polyethersulfone nanocomposite membranes.

PubMed

Munnawar, Iqra; Iqbal, Sadia S; Anwar, Muhammad N; Batool, Mehwish; Tariq, Sheraz; Faitma, Nosheen; Khan, Asim L; Khan, Asad U; Nazar, Umair; Jamil, Tahir; Ahmad, Nasir M

2017-11-01

Antifouling polyethersulfone (PES) membranes for water disinfection were fabricated by incorporating varying concentrations of carbohydrate polymer chitosan and Zinc oxide hybrid nanoparticles (CS-ZnO HNPS). The CS-ZnO HNPS were prepared using chemical precipitation method and were characterized using SEM, XRD and FTIR. The membranes were then fabricated by incorporating nanoparticles of CS-ZnO HNPS with three different concentrations of 5%, 10% and 15% w/w in the casting solution of PES through phase inversion method. The influence of nano-sized CS-ZnO HNPS on the properties of PES was characterized to study morphology, contact angle, water retention, surface roughness and permeability flux. The membranes with the maximum concentrations of 15% HNPS resulted in larger mean pore sizes and lowest contact angle value as compare to the pristine PES membrane. The prepared membranes exhibited significant water permeability, hydrophilicity and prevention against microbial fouling. The prepared membranes were observed to have significant antibacterial as well as antifungal properties due to the synergistic effect of chitosan and ZnO against both bacteria of the type of S. Aureus, B. Cereus, E. coli, and fungi such as S. typhi, A. fumigatus and F. solani. Copyright © 2017. Published by Elsevier Ltd.

An atomic force microscopy study on fouling characteristics of modified PES membrane in submerged membrane bioreactor for domestic wastewater treatment

NASA Astrophysics Data System (ADS)

Liu, Shuo; Han, Hongjun; Liu, Yanping; Wang, Baozhen

2008-10-01

To investigate the fouling characteristics of modified PES membrane in submerged Membrane Bioreactor (MBR) for domestic wastewater treatment, Atomic Force Microscope (AFM) study was conducted to analyze the microstructure characteristics of PES membrane. Surface roughness and section analysis of both virgin and fouled membrane were achieved by software of NanoScope 6.12. Compared to the virgin membrane, the average roughness (Ra), square average roughness (Rms) and ten points average roughness (Rz) of fouled membrane were increased by 100.6nm, 133.7nm and 330.7nm respectively. The section analysis results indicated that the cake layer formed and membrane pore blocked were the main causes for the increase of TMP. Micro-filtration resistance analysis was conducted to support the results of AFM analysis. It is showed that membrane resistance, cake resistance, pore blocking and irreversible fouling resistance is 0.755, 1.721 and 1.386 respectively, which contributed 20%, 44%, and 36%, respectively, to total resistance of submerged MBR (at MLSS 6000mg/L and flux 21.9L/m2Â.h). The results proved that AFM could be used to properly describe the fouling characteristics of modified PES membrane in submerged MBR through roughness and section analysis.

Electronic structure of hydrogenated diamond: Microscopical insight into surface conductivity

NASA Astrophysics Data System (ADS)

Iacobucci, S.; Alippi, Paola; Calvani, P.; Girolami, M.; Offi, F.; Petaccia, L.; Trucchi, D. M.

2016-07-01

We have correlated the surface conductivity of hydrogen-terminated diamond to the electronic structure in the Fermi region. Significant density of electronic states (DOS) in proximity of the Fermi edge has been measured by photoelectron spectroscopy (PES) on surfaces exposed to air, corresponding to a p -type electric conductive regime, while upon annealing a depletion of the DOS has been achieved, resembling the diamond insulating state. The surface and subsurface electronic structure has been determined, exploiting the different probing depths of PES applied in a photon energy range between 7 and 31 eV. Ab initio density functional calculations including surface charge depletion and band-bending effects favorably compare with electronic states measured by angular-resolved photoelectron spectroscopy. Such states are organized in the energy-momentum space in a twofold structure: one, bulk-derived, band disperses in the Γ -X direction with an average hole effective mass of (0.43 ±0.02 ) m0 , where m0 is the bare electron mass; a second flatter band, with an effective mass of (2.2 ±0.9 ) m0 , proves that a hole gas confined in the topmost layers is responsible for the conductivity of the (2 ×1 ) hydrogen-terminated diamond (100 ) surface.

Processing of action- but not stimulus-related prediction errors differs between active and observational feedback learning.

PubMed

Kobza, Stefan; Bellebaum, Christian

2015-01-01

Learning of stimulus-response-outcome associations is driven by outcome prediction errors (PEs). Previous studies have shown larger PE-dependent activity in the striatum for learning from own as compared to observed actions and the following outcomes despite comparable learning rates. We hypothesised that this finding relates primarily to a stronger integration of action and outcome information in active learners. Using functional magnetic resonance imaging, we investigated brain activations related to action-dependent PEs, reflecting the deviation between action values and obtained outcomes, and action-independent PEs, reflecting the deviation between subjective values of response-preceding cues and obtained outcomes. To this end, 16 active and 15 observational learners engaged in a probabilistic learning card-guessing paradigm. On each trial, active learners saw one out of five cues and pressed either a left or right response button to receive feedback (monetary win or loss). Each observational learner observed exactly those cues, responses and outcomes of one active learner. Learning performance was assessed in active test trials without feedback and did not differ between groups. For both types of PEs, activations were found in the globus pallidus, putamen, cerebellum, and insula in active learners. However, only for action-dependent PEs, activations in these structures and the anterior cingulate were increased in active relative to observational learners. Thus, PE-related activity in the reward system is not generally enhanced in active relative to observational learning but only for action-dependent PEs. For the cerebellum, additional activations were found across groups for cue-related uncertainty, thereby emphasising the cerebellum's role in stimulus-outcome learning. Copyright © 2014 Elsevier Ltd. All rights reserved.

Angiographic patterns of restenosis with 2nd generation drug-eluting stent: comparative analysis from a 10-year single-center experience .

PubMed

Lee, Sahmin; Yoon, Chang-Hwan; Oh, Il-Young; Suh, Jung-Won; Cho, Young-Seok; Cho, Goo-Yeong; Chae, In-Ho; Choi, Dong-Ju; Youn, Tae-Jin

2015-01-01

The angiographic features of restenosis contain prognostic information. However, restenosis patterns of the new generation drug-eluting stents (DES), everolimus-(EES) and resolute zotarolimus-eluting stent (ZES) have not been described.A total of 210 consecutive patients with DES restenosis were enrolled from 2003 to 2012. We analyzed 217 restenotic lesions after DES implantation, and compared the morphologic characteristics of the 2nd generation DES restenosis to those of restenosis with 2 first generation DES, sirolimus-(SES) and paclitaxel-eluting stent (PES).Baseline characteristics were comparable between the different stent groups. The incidence of focal restenosis was significantly lower for PES than the other stents (49.5% versus 87.0%, 76.2%, and 82.1% for PES versus SES, EES, and ZES, respectively, P < 0.001). When considering the pattern of restenosis solely within the stent margins, a further clear distinction between PES and other stents was observed (40.0% versus 92.9%, 88.9%, and 81.2% in PES versus SES, EES, and ZES, respectively, P < 0.001). There were no significant differences in restenosis patterns among SES, EES, and ZES. In multivariate analysis, PES implantation, hypertension, and age were associated with non-focal type of restenosis after DES implantation. After the introduction of EES and ZES into routine clinical practice in 2008, focal restenosis significantly increased from 63.9% to 76.7% and diffuse restenosis significantly decreased from 26.4% to 11.0% (P = 0.045).Focal restenosis was the most common pattern of restenosis in the new generation DES and the incidence of diffuse restenosis significantly decreased with the introduction of the 2nd generation DES.

An Ab Initio Based Potential Energy Surface for Water

NASA Technical Reports Server (NTRS)

Partridge, Harry; Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

1996-01-01

We report a new determination of the water potential energy surface. A high quality ab initio potential energy surface (PES) and dipole moment function of water have been computed. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base. The adjustment is small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Of the 27,245 assigned transitions in the HITRAN 92 data base for H2(O-16), the overall root mean square (rms) deviation between the computed and observed line positions is 0.125/cm. However the deviations do not correspond to a normal distribution: 69% of the lines have errors less than 0.05/cm. Overall, the agreement between the line intensities computed in the present work and those contained in the data base is quite good, however there are a significant number of line strengths which differ greatly.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xiaohong; Bowman, Joel M., E-mail: jmbowma@emory.edu; Huang, Xinchuan

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 frommore » 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.« less

bcc-to-hcp transformation pathways for iron versus hydrostatic pressure: Coupled shuffle and shear modes

NASA Astrophysics Data System (ADS)

Liu, J. B.; Johnson, D. D.

2009-04-01

Using density-functional theory, we calculate the potential-energy surface (PES), minimum-energy pathway (MEP), and transition state (TS) versus hydrostatic pressure σhyd for the reconstructive transformation in Fe from body-centered cubic (bcc) to hexagonal closed-packed (hcp). At fixed σhyd , the PES is described by coupled shear (γ) and shuffle (η) modes and is determined from structurally minimized hcp-bcc energy differences at a set of (η,γ) . We fit the PES using symmetry-adapted polynomials, permitting the MEP to be found analytically. The MEP is continuous and fully explains the transformation and its associated magnetization and volume discontinuity at TS. We show that σhyd (while not able to induce shear) dramatically alters the MEP to drive reconstruction by a shuffle-only mode at ≤30GPa , as observed. Finally, we relate our polynomial-based results to Landau and nudge-elastic-band approaches and show they yield incorrect MEP in general.

Wigner Distribution Functions as a Tool for Studying Gas Phase Alkali Metal Plus Noble Gas Collisions

DTIC Science & Technology

2014-03-27

ii List of Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii I...t, E) Wigner Distribution Function ii List of Acronyms Acronym Definition WDF Wigner Distribution Function PES Potential Energy Surface DPAL Diode

Pes planus and paediatric obesity: a systematic review of the literature.

PubMed

Stolzman, S; Irby, M B; Callahan, A B; Skelton, J A

2015-04-01

Children with obesity report musculoskeletal pain more than normal-weight children; this may be linked with literature suggesting children with obesity have higher prevalence of pes planus (flatfoot). To further elucidate whether this relation occurs, we conducted a systematic literature review on the co-occurrence of pes planus and paediatric obesity. Empirical articles published until September 2013 were obtained through an electronic search of MEDLINE and SPORTDiscus; included articles examined the association between body weight and pes planus in children. Thirteen cross-sectional studies of varied designs were identified. Methods used to diagnose pes planus varied between studies: imaging modalities, anthropometric measurements and clinical examination. Across all studies, pes planus prevalence among children with obesity ranged widely from 14 to 67%. Nearly all studies indicated increasing pes planus in children with increasing weight. No studies evaluated pain/complications related to pes planus. Our review suggests increased prevalence of pes planus among children with obesity or increasing weight status. Because of differing methodologies, lack of consensus regarding the pes planus definition, the dearth of investigation into pain/complications and the few existing studies, more research is needed to determine a relation between children's body weight, pes planus and associated effects on pain and function. © 2015 World Obesity.

Nuclear quantum effects on adsorption of H2 and isotopologues on metal ions

NASA Astrophysics Data System (ADS)

Savchenko, Ievgeniia; Gu, Bing; Heine, Thomas; Jakowski, Jacek; Garashchuk, Sophya

2017-02-01

The nuclear quantum effects on the zero-point energy (ZPE), influencing adsorption of H2 and isotopologues on metal ions, are examined using normal mode analysis of ab initio electronic structure results for complexes with 17 metal cations. The lightest metallic nuclei, Li and Be, are found to be the most 'quantum'. The largest selectivity in adsorption is predicted for Cu, Ni and Co ions. Analysis of the nuclear wavepacket dynamics on the ground state electronic potential energy surfaces (PES) performed for complexes of Li+ and Cu+2 with H2/D2/HD shows that the PES anharmonicity changes the ZPE by up to 9%.

Event-related potentials for post-error and post-conflict slowing.

PubMed

Chang, Andrew; Chen, Chien-Chung; Li, Hsin-Hung; Li, Chiang-Shan R

2014-01-01

In a reaction time task, people typically slow down following an error or conflict, each called post-error slowing (PES) and post-conflict slowing (PCS). Despite many studies of the cognitive mechanisms, the neural responses of PES and PCS continue to be debated. In this study, we combined high-density array EEG and a stop-signal task to examine event-related potentials of PES and PCS in sixteen young adult participants. The results showed that the amplitude of N2 is greater during PES but not PCS. In contrast, the peak latency of N2 is longer for PCS but not PES. Furthermore, error-positivity (Pe) but not error-related negativity (ERN) was greater in the stop error trials preceding PES than non-PES trials, suggesting that PES is related to participants' awareness of the error. Together, these findings extend earlier work of cognitive control by specifying the neural correlates of PES and PCS in the stop signal task.

Highly accurate potential energy surface, dipole moment surface, rovibrational energy levels, and infrared line list for {sup 32}S{sup 16}O{sub 2} up to 8000 cm{sup −1}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Xinchuan, E-mail: Xinchuan.Huang-1@nasa.gov, E-mail: Timothy.J.Lee@nasa.gov; Schwenke, David W., E-mail: David.W.Schwenke@nasa.gov; Lee, Timothy J., E-mail: Xinchuan.Huang-1@nasa.gov, E-mail: Timothy.J.Lee@nasa.gov

2014-03-21

A purely ab initio potential energy surface (PES) was refined with selected {sup 32}S{sup 16}O{sub 2} HITRAN data. Compared to HITRAN, the root-mean-squares error (σ{sub RMS}) for all J = 0–80 rovibrational energy levels computed on the refined PES (denoted Ames-1) is 0.013 cm{sup −1}. Combined with a CCSD(T)/aug-cc-pV(Q+d)Z dipole moment surface (DMS), an infrared (IR) line list (denoted Ames-296K) has been computed at 296 K and covers up to 8000 cm{sup −1}. Compared to the HITRAN and CDMS databases, the intensity agreement for most vibrational bands is better than 85%–90%. Our predictions for {sup 34}S{sup 16}O{sub 2} band origins,more » higher energy {sup 32}S{sup 16}O{sub 2} band origins and missing {sup 32}S{sup 16}O{sub 2} IR bands have been verified by most recent experiments and available HITRAN data. We conclude that the Ames-1 PES is able to predict {sup 32/34}S{sup 16}O{sub 2} band origins below 5500 cm{sup −1} with 0.01–0.03 cm{sup −1} uncertainties, and the Ames-296K line list provides continuous, reliable and accurate IR simulations. The K{sub a}-dependence of both line position and line intensity errors is discussed. The line list will greatly facilitate SO{sub 2} IR spectral experimental analysis, as well as elimination of SO{sub 2} lines in high-resolution astronomical observations.« less

Versatile and Rapid Postfunctionalization from Cyclodextrin Modified Host Polymeric Membrane Substrate.

PubMed

Deng, Jie; Liu, Xinyue; Zhang, Shuqing; Cheng, Chong; Nie, Chuanxiong; Zhao, Changsheng

2015-09-08

Surface modification has long been of great interest to impart desired functionalities to the bioimplants. However, due to the limitations of recent technologies in surface modification, it is highly desirable to explore novel protocols, which can advantageously and efficiently endow the inert material surfaces with versatile biofunctionalities. Herein, to achieve versatile and rapid postfunctionalization of polymeric membrane, we demonstrate a new strategy for the fabrication of β-cyclodextrin (β-CD) modified host membrane substrate that can recognize a series of well-designed guest macromolecules. The surface assembly procedure was driven by the host-guest interaction between adamantane (Ad) and β-CD. β-CD immobilized host membrane was fabricated via two steps: (1) epoxy groups enriched poly(ether sulfone) (PES) membrane was first prepared via in situ cross-linking polymerization and subsequently phase separation; (2) mono-6-deoxy-6-ethylenediamine-β-CD (EDA-β-CD) was then anchored onto the surface of the epoxy functionalized PES membrane to obtain PES-CD. Subsequently, three types of Ad-terminated polymers, including Ad-poly(styrenesulfonate-co-sodium acrylate) (Ad-PSA), Ad-methoxypoly(ethylene glycol) (Ad-PEG), and Ad-poly(methyl chloride-quaternized 2-(dimethylamino)ethyl methacrylate (Ad-PMT), were separately assembled onto the β-CD immobilized surfaces to endow the membranes with anticoagulant, antifouling, and antibacterial capability, respectively. Activated partial thromboplastin time (APTT), thrombin time (TT), and prothrombin time (PT) measurements were carried out to explore the anticoagulant activity. The antifouling capability was evaluated via protein adsorption and platelet adhesion measurements. Moreover, Staphyllococcous aureus (S. aureus) was selected as model bacteria to evaluate the antibacterial ability of the functionalized membranes. The results indicated that well-regulated blood compatibility, antifouling capability, and bactericidal activity could be achieved by the proposed rapid postfunctionalization on polymeric membranes. This approach of versatile and rapid postfunctionalization is promising for the preparation of multifunctional polymeric membrane materials to meet with various demands for the further applications.

Analysis of the red and green optical absorption spectrum of gas phase ammonia

NASA Astrophysics Data System (ADS)

Zobov, Nikolai F.; Coles, Phillip A.; Ovsyannikov, Roman I.; Kyuberis, Aleksandra A.; Hargreaves, Robert J.; Bernath, Peter F.; Tennyson, Jonathan; Yurchenko, Sergei N.; Polyansky, Oleg L.

2018-04-01

Room temperature NH3 absorption spectra recorded at the Kitt Peak National Solar Observatory in 1980 are analyzed. The spectra cover two regions in the visible: 15,200 - 15,700 cm-1 and 17,950 - 18,250 cm-1. These high overtone rotation-vibration spectra are analyzed using both combination differences and variational line lists. Two variational line lists were computed using the TROVE nuclear motion program: one is based on an ab initio potential energy surface (PES) while the other used a semi-empirical PES. Ab initio dipole moment surfaces are used in both cases. 95 energy levels with J = 1 - 7 are determined from analysis of the experimental spectrum in the 5νNH (red) region and 46 for 6νNH (green) region. These levels span four vibrational bands in each of the two regions, associated with stretching overtones.

Are in-shoe pressure characteristics in symptomatic idiopathic pes cavus related to the location of foot pain?

PubMed

Crosbie, Jack; Burns, Joshua

2008-01-01

People who have extremely high arched feet may be subject to substantial levels of foot pain, despite the lack of obvious pathology. This study sought to investigate the effect of pes cavus on pain intensity and location and on the magnitude and distribution of foot pressure. Measurements were derived from the more symptomatic foot of 130 participants with painful, idiopathic pes cavus. Data were collected using Pedar in-shoe pressure sensors and averaged over nine randomly selected steps. Participant information, including location and intensity of pain, Foot Posture Index values and anthropometric and "quality of life" variables, were also recorded. Painful idiopathic pes cavus seems to provoke a more cautious gait pattern than normal, with reduced peak and mean pressure values, particularly in the fore- and rear-foot regions. In particular, participants with pain confined to the rear-foot exhibit an antalgic gait pattern, with lower pressure values and a longer period of foot-ground contact in the heel region than those with pain only in the fore-foot. We determined no clear predictors of pain in terms of foot posture or demographics, although people with high body mass index values are more likely to have pain in several regions. The relationship between the posture of the foot and the presentation of pain remains unclear, however we believe that the presence of heel pain in pes cavus may be more restricting than fore-foot pain.

Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Lai-Sheng, E-mail: Lai-Sheng-Wang@brown.edu

2015-07-28

Electrospray ionization (ESI) has become an essential tool in chemical physics and physical chemistry for the production of novel molecular ions from solution samples for a variety of spectroscopic experiments. ESI was used to produce free multiply-charged anions (MCAs) for photoelectron spectroscopy (PES) in the late 1990 s, allowing many interesting properties of this class of exotic species to be investigated. Free MCAs are characterized by strong intramolecular Coulomb repulsions, which create a repulsive Coulomb barrier (RCB) for electron emission. The RCB endows many fascinating properties to MCAs, giving rise to meta-stable anions with negative electron binding energies. Recent developmentmore » in the PES of MCAs includes photoelectron imaging to examine the influence of the RCB on the electron emission dynamics, pump-probe experiments to examine electron tunneling through the RCB, and isomer-specific experiments by coupling PES with ion mobility for biological MCAs. The development of a cryogenically cooled Paul trap has led to much better resolved PE spectra for MCAs by creating vibrationally cold anions from the room temperature ESI source. Recent advances in coupling the cryogenic Paul trap with PE imaging have allowed high-resolution PE spectra to be obtained for singly charged anions produced by ESI. In particular, the observation of dipole-bound excited states has made it possible to conduct vibrational autodetachment spectroscopy and resonant PES, which yield much richer vibrational spectroscopic information for dipolar free radicals than traditional PES.« less

Global investigation of potential energy surfaces for the pyrolysis of C(1)-C(3) hydrocarbons: toward the development of detailed kinetic models from first principles.

PubMed

Ryazantsev, Mikhail N; Jamal, Adeel; Maeda, Satoshi; Morokuma, Keiji

2015-11-07

Detailed kinetic models (DKMs) are the most fundamental "bottom-up" approaches to computational investigation of the pyrolysis and oxidation of fuels. The weakest points of existing DKMs are incomplete information about the reaction types that can be involved in the potential energy surfaces (PESs) in pyrolysis and oxidation processes. Also, the computational thermodynamic parameters available in the literature vary widely with the level of theory employed. More sophisticated models require improvement both in our knowledge of the type of the reactions involved and the consistency of thermodynamic and kinetic parameters. In this paper, we aim to address these issues by developing ab initio models that can be used to describe early stages of pyrolysis of C1-C3 hydrocarbons. We applied a recently developed global reaction route mapping (GRRM) strategy to systematically investigate the PES of the pyrolysis of C1-C3 hydrocarbons at a consistent level of theory. The reactions are classified into 14 reaction types. The critical points on the PES for all reactions in the network are calculated at the highly accurate UCCSD(T)-F12b/cc-pVTZ//UM06-2X/cc-pVTZ level of theory. The data reported in this paper can be used for first principle calculations of kinetic constants and for a subsequent study on modeling the evolution of the species from the reaction network of the pyrolysis and oxidation of C1-C3 hydrocarbons.

Acceleration of saddle-point searches with machine learning.

PubMed

Peterson, Andrew A

2016-08-21

In atomistic simulations, the location of the saddle point on the potential-energy surface (PES) gives important information on transitions between local minima, for example, via transition-state theory. However, the search for saddle points often involves hundreds or thousands of ab initio force calls, which are typically all done at full accuracy. This results in the vast majority of the computational effort being spent calculating the electronic structure of states not important to the researcher, and very little time performing the calculation of the saddle point state itself. In this work, we describe how machine learning (ML) can reduce the number of intermediate ab initio calculations needed to locate saddle points. Since machine-learning models can learn from, and thus mimic, atomistic simulations, the saddle-point search can be conducted rapidly in the machine-learning representation. The saddle-point prediction can then be verified by an ab initio calculation; if it is incorrect, this strategically has identified regions of the PES where the machine-learning representation has insufficient training data. When these training data are used to improve the machine-learning model, the estimates greatly improve. This approach can be systematized, and in two simple example problems we demonstrate a dramatic reduction in the number of ab initio force calls. We expect that this approach and future refinements will greatly accelerate searches for saddle points, as well as other searches on the potential energy surface, as machine-learning methods see greater adoption by the atomistics community.

Acceleration of saddle-point searches with machine learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Andrew A., E-mail: andrew-peterson@brown.edu

In atomistic simulations, the location of the saddle point on the potential-energy surface (PES) gives important information on transitions between local minima, for example, via transition-state theory. However, the search for saddle points often involves hundreds or thousands of ab initio force calls, which are typically all done at full accuracy. This results in the vast majority of the computational effort being spent calculating the electronic structure of states not important to the researcher, and very little time performing the calculation of the saddle point state itself. In this work, we describe how machine learning (ML) can reduce the numbermore » of intermediate ab initio calculations needed to locate saddle points. Since machine-learning models can learn from, and thus mimic, atomistic simulations, the saddle-point search can be conducted rapidly in the machine-learning representation. The saddle-point prediction can then be verified by an ab initio calculation; if it is incorrect, this strategically has identified regions of the PES where the machine-learning representation has insufficient training data. When these training data are used to improve the machine-learning model, the estimates greatly improve. This approach can be systematized, and in two simple example problems we demonstrate a dramatic reduction in the number of ab initio force calls. We expect that this approach and future refinements will greatly accelerate searches for saddle points, as well as other searches on the potential energy surface, as machine-learning methods see greater adoption by the atomistics community.« less

Nucleolar protein PES1 is a marker of neuroblastoma outcome and is associated with neuroblastoma differentiation

PubMed Central

Nakaguro, Masato; Kiyonari, Shinichi; Kishida, Satoshi; Cao, Dongliang; Murakami-Tonami, Yuko; Ichikawa, Hitoshi; Takeuchi, Ichiro; Nakamura, Shigeo; Kadomatsu, Kenji

2015-01-01

Neuroblastoma (NB) is a childhood malignant tumor that arises from precursor cells of the sympathetic nervous system. Spontaneous regression is a phenomenon unique to NBs and is caused by differentiation of tumor cells. PES1 is a multifunctional protein with roles in both neural development and ribosome biogenesis. Various kinds of models have revealed the significance of PES1 in neurodevelopment. However, the roles of PES1 in NB tumorigenesis and differentiation have remained unknown. Here we show that NB cases with MYCN amplification and clinically unfavorable stage (INSS stage 4) express higher levels of PES1. High PES1 expression was associated with worse overall and relapse-free survival. In NB cell lines, PES1 knockdown suppressed tumor cell growth and induced apoptosis. This growth inhibition was associated with the expression of NB differentiation markers. However, when the differentiation of NB cell lines was induced by the use of all-trans retinoic acid, there was a corresponding decrease in PES1 expression. Pes1 expression of tumorspheres originated from MYCN transgenic mice also diminished after the induction of differentiation with growth factors. We also reanalyzed the distribution of PES1 in the nucleolus. PES1 was localized in the dense fibrillar component, but not in the granular component of nucleoli. After treatment with the DNA-damaging agent camptothecin, this distribution was dramatically changed to diffuse nucleoplasmic. These data suggest that PES1 is a marker of NB outcome, that it regulates NB cell proliferation, and is associated with NB differentiation. PMID:25557119

Improving the Force Field Description of Tyrosine-Choline Cation-π Interactions: QM Investigation of Phenol-N(Me)4+ Interactions.

PubMed

Khan, Hanif M; Grauffel, Cédric; Broer, Ria; MacKerell, Alexander D; Havenith, Remco W A; Reuter, Nathalie

2016-11-08

Cation-π interactions between tyrosine amino acids and compounds containing N,N,N-trimethylethanolammonium (N(CH 3 ) 3 ) are involved in the recognition of histone tails by chromodomains and in the recognition of phosphatidylcholine (PC) phospholipids by membrane-binding proteins. Yet, the lack of explicit polarization or charge transfer effects in molecular mechanics force fields raises questions about the reliability of the representation of these interactions in biomolecular simulations. Here, we investigate the nature of phenol-tetramethylammonium (TMA) interactions using quantum mechanical (QM) calculations, which we also use to evaluate the accuracy of the additive CHARMM36 and Drude polarizable force fields in modeling tyrosine-choline interactions. We show that the potential energy surface (PES) obtained using SAPT2+/aug-cc-pVDZ compares well with the large basis-set CCSD(T) PES when TMA approaches the phenol ring perpendicularly. Furthermore, the SAPT energy decomposition reveals comparable contributions from electrostatics and dispersion in phenol-TMA interactions. We then compared the SAPT2+/aug-cc-pVDZ PES obtained along various approach directions to the corresponding PES obtained with CHARMM, and we show that the force field accurately reproduces the minimum distances while the interaction energies are underestimated. The use of the Drude polarizable force field significantly improves the interaction energies but decreases the agreement on distances at energy minima. The best agreement between force field and QM PES is obtained by modifying the Lennard-Jones terms for atom pairs involved in the phenol-TMA cation-π interactions. This is further shown to improve the correlation between the occupancy of tyrosine-choline cation-π interactions obtained from molecular dynamics simulations of a bilayer-bound bacterial phospholipase and experimental affinity data of the wild-type protein and selected mutants.

Activation Strain Analysis of SN2 Reactions at C, N, O, and F Centers

PubMed Central

2017-01-01

Fundamental principles that determine chemical reactivity and reaction mechanisms are the very foundation of chemistry and many related fields of science. Bimolecular nucleophilic substitutions (SN2) are among the most common and therefore most important reaction types. In this report, we examine the trends in the SN2 reactions with respect to increasing electronegativity of the reaction center by comparing the well-studied backside SN2 Cl– + CH3Cl with similar Cl– substitutions on the isoelectronic series with the second period elements N, O, and F in place of C. Relativistic (ZORA) DFT calculations are used to construct the gas phase reaction potential energy surfaces (PES), and activation strain analysis, which allows decomposition of the PES into the geometrical strain and interaction energy, is employed to analyze the observed trends. We find that SN2@N and SN2@O have similar PES to the prototypical SN2@C, with the well-defined reaction complex (RC) local minima and a central barrier, but all stationary points are, respectively, increasingly stable in energy. The SN2@F, by contrast, exhibits only a single-well PES with no barrier. Using the activation strain model, we show that the trends are due to the interaction energy and originate mainly from the decreasing energy of the empty acceptor orbital (σ*A–Cl) on the reaction center A in the order of C, N, O, and F. The decreasing steric congestion around the central atom is also a likely contributor to this trend. Additional decomposition of the interaction energy using Kohn–Sham molecular orbital (KS-MO) theory provides further support for this explanation, as well as suggesting electrostatic energy as the primary reason for the distinct single-well PES profile for the FCl reaction. PMID:28045531

Activation Strain Analysis of SN2 Reactions at C, N, O, and F Centers.

PubMed

Kubelka, Jan; Bickelhaupt, F Matthias

2017-02-02

Fundamental principles that determine chemical reactivity and reaction mechanisms are the very foundation of chemistry and many related fields of science. Bimolecular nucleophilic substitutions (S N 2) are among the most common and therefore most important reaction types. In this report, we examine the trends in the S N 2 reactions with respect to increasing electronegativity of the reaction center by comparing the well-studied backside S N 2 Cl - + CH 3 Cl with similar Cl - substitutions on the isoelectronic series with the second period elements N, O, and F in place of C. Relativistic (ZORA) DFT calculations are used to construct the gas phase reaction potential energy surfaces (PES), and activation strain analysis, which allows decomposition of the PES into the geometrical strain and interaction energy, is employed to analyze the observed trends. We find that S N 2@N and S N 2@O have similar PES to the prototypical S N 2@C, with the well-defined reaction complex (RC) local minima and a central barrier, but all stationary points are, respectively, increasingly stable in energy. The S N 2@F, by contrast, exhibits only a single-well PES with no barrier. Using the activation strain model, we show that the trends are due to the interaction energy and originate mainly from the decreasing energy of the empty acceptor orbital (σ* A-Cl ) on the reaction center A in the order of C, N, O, and F. The decreasing steric congestion around the central atom is also a likely contributor to this trend. Additional decomposition of the interaction energy using Kohn-Sham molecular orbital (KS-MO) theory provides further support for this explanation, as well as suggesting electrostatic energy as the primary reason for the distinct single-well PES profile for the FCl reaction.

Collisional excitation of NH(X{sup 3}Σ{sup −}) by Ne: Potential energy surface, scattering calculations, and comparison with experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bouhafs, Nezha; Lique, François, E-mail: francois.lique@univ-lehavre.fr

2015-11-14

We present a new three-dimensional potential energy surface (PES) for the NH(X{sup 3}Σ{sup −})–Ne van der Waals system, which explicitly takes into account the NH vibrational motion. Ab initio calculations of the NH–Ne PES were carried out using the open-shell single- and double-excitation coupled cluster approach with non-iterative perturbational treatment of triple excitations [RCCSD(T)]. The augmented correlation-consistent quadruple zeta (aug-cc-pVQZ) basis set was employed. Mid-bond functions were also included in order to improve the accuracy in the van der Waals well. Using this new PES, we have studied the collisional excitation of NH(X{sup 3}Σ{sup −}) by Ne. Close-coupling calculations ofmore » the collisional excitation cross sections of the fine-structure levels of NH by Ne are performed for energies up to 3000 cm{sup −1}, which yield, after thermal average, rate coefficients up to 350 K. The propensity rules between fine-structure levels are reported, and it is found that F-conserving cross sections are larger than F-changing cross sections even if the propensity rules are not as strong as for the NH–He system. The calculated rate coefficients are compared with available experimental measurements at room temperature and a fairly good agreement is found between experimental and theoretical data, confirming the good quality of the scattering calculations and also the accuracy of the potential energy surface used in this work.« less

Digit-only sauropod pes trackways from China – evidence of swimming or a preservational phenomenon?

PubMed Central

Xing, Lida; Li, Daqing; Falkingham, Peter L.; Lockley, Martin G.; Benton, Michael J.; Klein, Hendrik; Zhang, Jianping; Ran, Hao; Persons, W. Scott; Dai, Hui

2016-01-01

For more than 70 years unusual sauropod trackways have played a pivotal role in debates about the swimming ability of sauropods. Most claims that sauropods could swim have been based on manus-only or manus-dominated trackways. However none of these incomplete trackways has been entirely convincing, and most have proved to be taphonomic artifacts, either undertracks or the result of differential depth of penetration of manus and pes tracks, but otherwise showed the typical pattern of normal walking trackways. Here we report an assemblage of unusual sauropod tracks from the Lower Cretaceous Hekou Group of Gansu Province, northern China, characterized by the preservation of only the pes claw traces, that we interpret as having been left by walking, not buoyant or swimming, individuals. They are interpreted as the result of animals moving on a soft mud-silt substrate, projecting their claws deeply to register their traces on an underlying sand layer where they gained more grip during progression. Other sauropod walking trackways on the same surface with both pes and manus traces preserved, were probably left earlier on relatively firm substrates that predated the deposition of soft mud and silt . Presently, there is no convincing evidence of swimming sauropods from their trackways, which is not to say that sauropods did not swim at all. PMID:26888058

Improved antifouling potential of polyether sulfone polymeric membrane containing silver nanoparticles: self-cleaning membranes.

PubMed

Rana, Sidra; Nazar, Umair; Ali, Jafar; Ali, Qurat Ul Ain; Ahmad, Nasir M; Sarwar, Fiza; Waseem, Hassan; Jamil, Syed Umair Ullah

2018-06-01

A new strategy to enhance the antifouling potential of polyether sulfone (PES) membrane is presented. Chemically synthesized silver nanoparticles (AgNPs) were used to prepare a mixed-matrix PES membrane by the phase inversion technique. Primarily, AgNPs synthesis was confirmed by surface plasmon resonance at 410-430 nm using UV-Visible spectroscopy. X-ray diffraction analysis revealed that AgNPs were crystalline with a diameter of 21 ± 2 nm. Furthermore, PES membranes were characterized by energy dispersive X-ray spectroscopy to confirm the incorporation of AgNPs in membranes. Hydrophilicity of the membranes was enhanced, whereas roughness, mechanical strength and biofouling were relatively reduced after embedding the AgNPs. Antibacterial potential of AgNPs was evaluated for E. coli in the disc diffusion and colony-forming unit (CFU) count method. All of the membranes were assessed for antifouling activity by filtering a control dilution (10 6  CFU/ml) of E. coli and by counting CFU. Anti-biofouling activity of the membrane was observed with different concentrations of AgNPs. Maximum reduction (66%) was observed in membrane containing 1.5% of AgNPs. The addition of antibiotic ceftriaxone enhanced the antibacterial effect of AgNPs in PES membranes. Our practicable antifouling strategy may be applied to other polymeric membranes which may pave the new way to achieve sustainable and self-cleaning membrane reactors on large scale.

Biodegradation of Jatropha curcas phorbol esters in soil.

PubMed

Devappa, Rakshit K; Makkar, Harinder Ps; Becker, Klaus

2010-09-01

Jatropha curcas seed cake is generated as a by-product during biodiesel production. Seed cake containing toxic phorbol esters (PEs) is currently used as a fertiliser and thus it is of eco-toxicological concern. In the present study the fate of PEs in soil was studied. Two approaches for the incorporation of PEs in soil were used. In the first, silica was bound to PEs, and in the second, seedcake was used. At day 0, the concentration of PEs in soil was 2.6 and 0.37 mg g(-1) for approach 1 and 2 respectively. PEs from silica bound PEs were completely degraded after 19, 12, 12 days (at 130 g kg(-1) moisture) and after 17, 9, 9 days (at 230 g kg(-1) moisture) at room temperature, 32 degrees C and 42 degrees C respectively. Similarly at these temperatures PEs from seed cake were degraded after 21, 17 and 17 days (at 130 g kg(-1) moisture) and after 23, 17, and 15 days (at 230 g kg(-1) moisture). Increase in temperature and moisture increased rate of PEs degradation. Using the snail (Physa fontinalis) bioassay, mortality by PE-amended soil extracts decreased with the decrease in PE concentration in soil. Jatropha PEs are biodegradable. The degraded products are innocuous. Copyright 2010 Society of Chemical Industry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Rui; School of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou 450011; Zheng, Limin

Theoretical studies of the potential energy surface (PES) and bound states are performed for the N{sub 2}–N{sub 2}O van der Waals (vdW) complex. A four-dimensional intermolecular PES is constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. Two equivalent T-shaped global minima are located, in which the O atom of N{sub 2}O monomer is near the N{sub 2} monomer. The intermolecular fundamental vibrational states are assigned by inspecting the orientation of the nodal surface of the wavefunctions. The calculated frequency formore » intermolecular disrotation mode is 23.086 cm{sup −1}, which is in good agreement with the available experimental data of 22.334 cm{sup −1}. A negligible tunneling splitting with the value of 4.2 MHz is determined for the ground vibrational state and the tunneling splitting increases as the increment of the vibrational frequencies. Rotational levels and transition frequencies are calculated for both isotopomers {sup 14}N{sub 2}–N{sub 2}O and {sup 15}N{sub 2}–N{sub 2}O. The accuracy of the PES is validated by the good agreement between theoretical and experimental results for the transition frequencies and spectroscopic parameters.« less

Potential energy surface and rate coefficients of protonated cyanogen (HNCCN+) induced by collision with helium (He) at low temperature

NASA Astrophysics Data System (ADS)

Bop, Cheikh T.; Faye, N. AB; Hammami, K.

2018-05-01

Nitriles have been identified in space. Accurately modeling their abundance requires calculations of collisional rate coefficients. These data are obtained by first computing potential energy surfaces (PES) and cross-sections using high accurate quantum methods. In this paper, we report the first interaction potential of the HNCCN+-He collisional system along with downward rate coefficients among the 11 lowest rotational levels of HNCCN+. The PES was calculated using the explicitly correlated coupled cluster approach with simple, second and non-iterative triple excitation (CCSD(T)-F12) in conjunction with the augmented-correlation consistent-polarized valence triple zeta (aug-cc-pVTZ) Gaussian basis set. It presents two local minima of ˜283 and ˜136 cm-1, the deeper one is located at R = 9 a0 towards the H end (HeṡṡṡHNCCN+). Using the so-computed PES, we calculated rotational cross-sections of HNCCN+ induced by collision with He for energies ranging up to 500 cm-1 with the exact quantum mechanical close coupling (CC) method. Downward rate coefficients were then worked out by thermally averaging the cross-sections at low temperature (T ≤ 100 K). The discussion on propensity rules showed that the odd Δj transitions were favored. The results obtained in this work may be crucially needed to accurately model the abundance of cyanogen and its protonated form in space.

Room temperature linelists for CO2 asymmetric isotopologues with ab initio computed intensities

NASA Astrophysics Data System (ADS)

Zak, Emil J.; Tennyson, Jonathan; Polyansky, Oleg L.; Lodi, Lorenzo; Zobov, Nikolay F.; Tashkun, Sergei A.; Perevalov, Valery I.

2017-12-01

The present paper reports room temperature line lists for six asymmetric isotopologues of carbon dioxide: 16O12C18O (628), 16O12C17O (627), 16O13C18O (638),16O13C17O (637), 17O12C18O (728) and 17O13C18O (738), covering the range 0-8000 cm-1. Variational rotation-vibration wavefunctions and energy levels are computed using the DVR3D software suite and a high quality semi-empirical potential energy surface (PES), followed by computation of intensities using an ab initio dipole moment surface (DMS). A theoretical procedure for quantifying sensitivity of line intensities to minor distortions of the PES/DMS renders our theoretical model as critically evaluated. Several recent high quality measurements and theoretical approaches are discussed to provide a benchmark of our results against the most accurate available data. Indeed, the thesis of transferability of accuracy among different isotopologues with the use of mass-independent PES is supported by several examples. Thereby, we conclude that the majority of line intensities for strong bands are predicted with sub-percent accuracy. Accurate line positions are generated using an effective Hamiltonian, constructed from the latest experiments. This study completes the list of relevant isotopologues of carbon dioxide; these line lists are available to remote sensing studies and inclusion in databases.

Experimental and theoretical study of rotationally inelastic diffraction of H{sub 2}(D{sub 2}) from methyl-terminated Si(111)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nihill, Kevin J.; Hund, Zachary M.; Sibener, S. J., E-mail: s-sibener@uchicago.edu

2016-08-28

Fundamental details concerning the interaction between H{sub 2} and CH{sub 3}–Si(111) have been elucidated by the combination of diffractive scattering experiments and electronic structure and scattering calculations. Rotationally inelastic diffraction (RID) of H{sub 2} and D{sub 2} from this model hydrocarbon-decorated semiconductor interface has been confirmed for the first time via both time-of-flight and diffraction measurements, with modest j = 0 → 2 RID intensities for H{sub 2} compared to the strong RID features observed for D{sub 2} over a large range of kinematic scattering conditions along two high-symmetry azimuthal directions. The Debye-Waller model was applied to the thermal attenuationmore » of diffraction peaks, allowing for precise determination of the RID probabilities by accounting for incoherent motion of the CH{sub 3}–Si(111) surface atoms. The probabilities of rotationally inelastic diffraction of H{sub 2} and D{sub 2} have been quantitatively evaluated as a function of beam energy and scattering angle, and have been compared with complementary electronic structure and scattering calculations to provide insight into the interaction potential between H{sub 2} (D{sub 2}) and hence the surface charge density distribution. Specifically, a six-dimensional potential energy surface (PES), describing the electronic structure of the H{sub 2}(D{sub 2})/CH{sub 3}−Si(111) system, has been computed based on interpolation of density functional theory energies. Quantum and classical dynamics simulations have allowed for an assessment of the accuracy of the PES, and subsequently for identification of the features of the PES that serve as classical turning points. A close scrutiny of the PES reveals the highly anisotropic character of the interaction potential at these turning points. This combination of experiment and theory provides new and important details about the interaction of H{sub 2} with a hybrid organic-semiconductor interface, which can be used to further investigate energy flow in technologically relevant systems.« less

Activities of Jatropha curcas phorbol esters in various bioassays.

PubMed

Devappa, Rakshit K; Rajesh, Sanjay K; Kumar, Vikas; Makkar, Harinder P S; Becker, Klaus

2012-04-01

Jatropha curcas seeds contain 30-35% oil, which can be converted to high quality biodiesel. However, Jatropha oil is toxic, ascribed to the presence of phorbol esters (PEs). In this study, isolated phorbol ester rich fraction (PEEF) was used to evaluate the activity of PEs using three aquatic species based bioassays (snail (Physa fontinalis), brine shrimp (Artemeia salina), daphnia (Daphnia magna)) and microorganisms. In all the bioassays tested, increase in concentration of PEs increased mortality with an EC(50) (48 h) of 0.33, 26.48 and 0.95 mg L(-1) PEs for snail, artemia and daphnia, respectively. The sensitivity of various microorganisms for PEs was also tested. Among the bacterial species tested, Streptococcus pyogenes and Proteus mirabilis were highly susceptible with a minimum inhibitory concentration (MIC) of 215 mg L(-1) PEs; and Pseudomonas putida were also sensitive with MIC of 251 mg L(-1) PEs. Similarly, Fusarium species of fungi exhibited EC(50) of 58 mg L(-1) PEs, while Aspergillus niger and Curvularia lunata had EC(50) of 70 mg L(-1). The snail bioassay was most sensitive with 100% snail mortality at 1 μg of PEs mL(-1). In conclusion, snail bioassay could be used to monitor PEs in Jatropha derived products such as oil, biodiesel, fatty acid distillate, kernel meal, cake, glycerol or for contamination in soil or other environmental matrices. In addition, PEs with molluscicidal/antimicrobial activities could be utilized for agricultural and pharmaceutical applications. Copyright © 2011 Elsevier Inc. All rights reserved.

When, why and how foot orthoses (FOs) should be prescribed for children with flexible pes planus: a Delphi survey of podiatrists

PubMed Central

Uden, Hayley; Kumar, Saravana; Banwell, Helen A.

2018-01-01

Background Flexible pes planus (flat feet) in children is a common reason parents and caregivers seek health professionals consult and a frequent reason podiatrists prescribe foot orthoses. Yet no universal agreement exists on the diagnosis of this condition, or when and how foot orthoses should be prescribed. The aim of this study was to garner consensus and agreement among podiatrists on the use of FOs for paediatric flexible pes planus. Methods A three round Delphi consensus survey was undertaken with 15 podiatry experts from Australia, New Zealand and the United Kingdom. Round One gathered consensus on the diagnosis and intervention into paediatric pes planus with specific questions on types of FOs and prescription variables used. Round Two and Three were based on answers from Round One and gathered agreement (rationale for choices) on a five point Likert scale. 70% of respondents had to agree to a statement for it to be accepted as consensus or agreement. Results Consensus and agreement was achieved for 83 statements directing the diagnosis of pes planus (using FPI-6 and/or rearfoot measures), common signs and symptoms (e.g., pain, fatigue, abnormal gait and other functional concerns) that direct when to intervene into paediatric flexible pes planus. Prefabricated orthoses were the preferred intervention where adequate control is gained with their use. When customised orthoses are prescribed, a vertical [heel] cast pour (71.4%) and minimal arch fill (76.9%) are the prescription variables of choice, plus or minus additional variables (i.e., medial heel (Kirby) skive, the use of a University of California Biomechanical Laboratory device or a medial flange) dependent on level of disorder and plane of excessive motion. Conclusions This study identified consensus and agreement on a series of diagnosis methods and interventions for the paediatric flexible pes planus. A clinical protocol was developed from the resultant consensus statements which provides clinicians with a series of evidenced-informed statements to better guide them on when, how and why FOs are used specific to this population. PMID:29682429

Impact of Fluoropolymer-Based Paclitaxel Delivery on Neointimal Proliferation and Vascular Healing: A Comparative Peripheral Drug-Eluting Stent Study in the Familial Hypercholesterolemic Swine Model of Femoral Restenosis.

PubMed

Gasior, Pawel; Cheng, Yanping; Valencia, Andres F; McGregor, Jenn; Conditt, Gerard B; Kaluza, Grzegorz L; Granada, Juan F

2017-05-01

A polymer-free peripheral paclitaxel-eluting stent (PES, Zilver PTX, Cook, IN) has shown to improve vessel patency after superficial femoral angioplasty. A new-generation fluoropolymer-based PES (FP-PES; Eluvia, Boston Scientific, MA) displaying more controlled and sustained paclitaxel delivery promise to improve the clinical outcomes of first-generation PES. We sought to compare the biological effect of paclitaxel delivered by 2 different stent-coating technologies (fluoropolymer-based versus polymer-free) on neointimal proliferation and healing response in the familial hypercholesterolemic swine model of femoral restenosis. The biological efficacy of clinically available FP-PES (n=12) and PES (n=12) was compared against a bare metal stent control (n=12; Innova, Boston Scientific, MA) after implantation in the femoral arteries of 18 familial hypercholesterolemic swine. Longitudinal quantitative vascular angiography and optical coherence tomography were performed at baseline and at 30 and 90 days. Histological evaluation was performed at 90 days. Ninety-day quantitative vascular angiography results showed a lower percent diameter stenosis for FP-PES (38.78% [31.27-47.66]) compared with PES (54.16% [42.60-61.97]) and bare metal stent (74.52% [47.23-100.00]; P <0.001). Ninety-day optical coherence tomography results demonstrated significantly lower neointimal area in FP-PES (8.01 mm 2 [7.65-9.21]) compared with PES (10.95 mm 2 [9.64-12.46]) and bare metal stent (13.83 mm 2 [11.53-17.03]; P <0.001). Histological evaluation showed larger lumen areas and evidence of higher biological activity (smooth muscle cell loss and fibrin deposition) in the FP-PES compared with PES and bare metal stent. In the familial hypercholesterolemic swine model of femoral restenosis, the implantation of an FP-PES resulted in lower levels of neointimal proliferation and sustained biological effect ≤90 days compared with a polymer-free stent-based approach. © 2017 American Heart Association, Inc.

Cation–π interactions in protein–ligand binding: theory and data-mining reveal different roles for lysine and arginine† †Electronic supplementary information (ESI) available: DLPNO-CCSD(T)/aug-cc-pVnZ benchmarks; PLIP geometric criteria; polycyclic aromatic ring visualizations; van der Waals surfaces of model complexes; absolute energies from DLPNO-CCSD(T)/aug-cc-pVTZ and SAPT2+3/aug-cc-pVDZ calculations; Cartesian coordinates; Table of PDB IDs and corresponding cation–π interactions identified (.xls). See DOI: 10.1039/c7sc04905f

PubMed Central

Kumar, Kiran; Woo, Shin M.; Siu, Thomas; Cortopassi, Wilian A.

2018-01-01

We have studied the cation–π interactions of neutral aromatic ligands with the cationic amino acid residues arginine, histidine and lysine using ab initio calculations, symmetry adapted perturbation theory (SAPT), and a systematic meta-analysis of all available Protein Data Bank (PDB) X-ray structures. Quantum chemical potential energy surfaces (PES) for these interactions were obtained at the DLPNO-CCSD(T) level of theory and compared against the empirical distribution of 2012 unique protein–ligand cation–π interactions found in X-ray crystal structures. We created a workflow to extract these structures from the PDB, filtering by interaction type and residue pKa. The gas phase cation–π interaction of lysine is the strongest by more than 10 kcal mol–1, but the empirical distribution of 582 X-ray structures lies away from the minimum on the interaction PES. In contrast, 1381 structures involving arginine match the underlying calculated PES with good agreement. SAPT analysis revealed that underlying differences in the balance of electrostatic and dispersion contributions are responsible for this behavior in the context of the protein environment. The lysine–arene interaction, dominated by electrostatics, is greatly weakened by a surrounding dielectric medium and causes it to become essentially negligible in strength and without a well-defined equilibrium separation. The arginine–arene interaction involves a near equal mix of dispersion and electrostatic attraction, which is weakened to a much smaller degree by the surrounding medium. Our results account for the paucity of cation–π interactions involving lysine, even though this is a more common residue than arginine. Aromatic ligands are most likely to interact with cationic arginine residues as this interaction is stronger than for lysine in higher polarity surroundings. PMID:29719674

Mode-Specific SN2 Reaction Dynamics.

PubMed

Wang, Yan; Song, Hongwei; Szabó, István; Czakó, Gábor; Guo, Hua; Yang, Minghui

2016-09-01

Despite its importance in chemistry, the microscopic dynamics of bimolecular nucleophilic substitution (SN2) reactions is still not completely elucidated. In this publication, the dynamics of a prototypical SN2 reaction (F(-) + CH3Cl → CH3F + Cl(-)) is investigated using a high-dimensional quantum mechanical model on an accurate potential energy surface (PES) and further analyzed by quasi-classical trajectories on the same PES. While the indirect mechanism dominates at low collision energies, the direct mechanism makes a significant contribution. The reactivity is found to depend on the specific reactant vibrational mode excitation. The mode specificity, which is more prevalent in the direct reaction, is rationalized by a transition-state-based model.

Direct Dynamics Simulation of the Thermal 3CH2 + 3O2 Reaction. Rate Constant and Product Branching Ratios.

PubMed

Lakshmanan, Sandhiya; Pratihar, Subha; Machado, Francisco B C; Hase, William L

2018-05-31

The reaction of 3 CH 2 with 3 O 2 is of fundamental importance in combustion, and the reaction is complex as a result of multiple extremely exothermic product channels. In the present study, direct dynamics simulations were performed to study the reaction on both the singlet and triplet potential energy surfaces (PESs). The simulations were performed at the UM06/6-311++G(d,p) level of theory. Trajectories were calculated at a temperature of 300 K, and all reactive trajectories proceeded through the carbonyl oxide Criegee intermediate, CH 2 OO, on both the singlet and triplet PESs. The triplet surface leads to only one product channel, H 2 CO + O( 3 P), while the singlet surface leads to eight product channels with their relative importance as CO + H 2 O > CO + OH + H ∼ H 2 CO + O( 1 D) > HCO + OH ∼ CO 2 + H 2 ∼ CO + H 2 + O( 1 D) > CO 2 + H + H > HCO + O( 1 D) + H. The reaction on the singlet PES is barrierless, consistent with experiment, and the total rate constant on the singlet surface is (0.93 ± 0.22) × 10 -12 cm 3 molecule -1 s -1 in comparison to the recommended experimental rate constant of 3.3 × 10 -12 cm 3 molecule -1 s -1 . The simulation product yields for the singlet PES are compared with experiment, and the most significant differences are for H, CO 2 , and H 2 O. The reaction on the triplet surface is also barrierless, inconsistent with experiment. A discussion is given of the need for future calculations to address (1) the barrier on the triplet PES for 3 CH 2 + 3 O 2 → 3 CH 2 OO, (2) the temperature dependence of the 3 CH 2 + 3 O 2 reaction rate constant and product branching ratios, and (3) the possible non-RRKM dynamics of the 1 CH 2 OO Criegee intermediate.

TSH and prolactin responses to thyrotropin releasing hormone (TRH) and domperidone in patients with empty sella syndrome.

PubMed

Valensi, P; Combes, M E; Perret, G; Attali, J R

1996-05-01

The aim of this study was to investigate TSH and PRL response to TRH and domperidone, an antidopaminergic drug which does not cross the blood-brain barrier, in 16 patients with primary empty sella (PES) and either normal or elevated plasma PRL level and to compare it with the response observed in 8 patients with prolactinoma. In the patients with PES and hyperprolactinemia, the PRL response to TRH was significantly lower than in the controls and the patients with PES and normal PRL, which suggests there is impaired PRL synthesis and release in cases of PES with hyperprolactinemia. The TSH response to domperidone was significantly elevated in patients with PES and either normal or elevated PRL, as in patients with prolactinoma. The PRL response to domperidone was significantly reduced in patients with PES and hyperprolactinemia as in patients with prolactionoma. These results suggestthat in PES with prolactinoma the inhibiting dopaminergic tone is increased on the thyrotropic cells and reduced on the lactotropic cells in PES with elevated PRL and that some patients with PES might bear a microprolactinoma in the bottom of the sella which remained undetected by the CT scan.

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.

Effect of gamma-ray irradiation at low doses on the performance of PES ultrafiltration membrane

NASA Astrophysics Data System (ADS)

Zhang, Xue; Niu, Lixia; Li, Fuzhi; Yu, Suping; Zhao, Xuan; Hu, Hongying

2016-10-01

The influence of gamma irradiation on the performance of polyether sulfone (PES) ultrafiltration (UF) membrane was investigated at low absorbed doses (0-75 kGy) using a cobalt source. The performance of the UF membranes was tested using low level radioactive wastewater (LLRW) containing three types of surfactants (anionic, cationic and nonionic surfactants). The physical and chemical properties of membrane surface were analyzed, and relationships between these properties and separation performance and fouling characteristics were determined. At 10-75 kGy irradiation, there were no significant changes observed in the membrane surface roughness or polymer functional groups, however the contact angle decreased sharply from 92° to ca. 70° at irradiation levels as low as 10 kGy. When membranes were exposed to the surfactant-containing LLRW, the flux decreased more sharply for higher dosed irradiated membranes, while flux in virgin membranes increased during the filtration processes. The study highlights that fouling properties of membrane may be changed due to the changes of surface hydrophilicity at low dose irradiation, while other surface properties and retentions remain stable. Therefore, a membrane fouling test with real or simulated wastewater is recommended to fully evaluate the membrane irradiation resistance.

Rotational excitations in para-H2+para-H2 collisions: full- and reduced-dimensional quantum wave packet studies comparing different potential energy surfaces.

PubMed

Otto, Frank; Gatti, Fabien; Meyer, Hans-Dieter

2008-02-14

We study the process of rotational excitation in the collisions of para-H(2) with para-H(2) by propagating wave packets with the multiconfiguration time-dependent Hartree (MCTDH) algorithm. Transition probabilities are then calculated by the method of Tannor and Weeks based on time-correlation functions. Calculations were carried out up to a total angular momentum of J=70 to compute integral cross sections up to 1.2 eV in collision energy and thermal rate coefficients from 100 to 3000 K. The process is studied on the full-dimensional potential energy surface of Boothroyd-Martin-Keogh-Peterson (BMKP) as well as on the rigid rotor surface of Diep and Johnson. We test the validity of the rigid rotor approximation by also considering two rigid rotor restrictions of the BMKP potential energy surface (PES). Additionally, we investigate a variant of the BMKP PES suggested by Pogrebnya and Clary [Chem. Phys. Lett. 363, 523 (2002)] with reduced anisotropy. We compare our results with previous theoretical data for the cross sections and with experimental data for the rate coefficients at low temperatures.

MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO⁺(H₂O) cluster using accurate potential energy and dipole moment surfaces.

PubMed

Homayoon, Zahra

2014-09-28

A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO(+)(H2O) cluster is reported. The PES is based on fitting of roughly 32,000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO(+)(H2O) and NO(+)(D2O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO(+)(H2O) and NO(+)(D2O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO(+)(H2O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water "antisymmetric" stretching mode with the low-frequency intermolecular modes results in intensity borrowing.

MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO+(H2O) cluster using accurate potential energy and dipole moment surfaces

NASA Astrophysics Data System (ADS)

Homayoon, Zahra

2014-09-01

A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO+(H2O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO+(H2O) and NO+(D2O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO+(H2O) and NO+(D2O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO+(H2O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water "antisymmetric" stretching mode with the low-frequency intermolecular modes results in intensity borrowing.

Vicarious reinforcement learning signals when instructing others.

PubMed

Apps, Matthew A J; Lesage, Elise; Ramnani, Narender

2015-02-18

Reinforcement learning (RL) theory posits that learning is driven by discrepancies between the predicted and actual outcomes of actions (prediction errors [PEs]). In social environments, learning is often guided by similar RL mechanisms. For example, teachers monitor the actions of students and provide feedback to them. This feedback evokes PEs in students that guide their learning. We report the first study that investigates the neural mechanisms that underpin RL signals in the brain of a teacher. Neurons in the anterior cingulate cortex (ACC) signal PEs when learning from the outcomes of one's own actions but also signal information when outcomes are received by others. Does a teacher's ACC signal PEs when monitoring a student's learning? Using fMRI, we studied brain activity in human subjects (teachers) as they taught a confederate (student) action-outcome associations by providing positive or negative feedback. We examined activity time-locked to the students' responses, when teachers infer student predictions and know actual outcomes. We fitted a RL-based computational model to the behavior of the student to characterize their learning, and examined whether a teacher's ACC signals when a student's predictions are wrong. In line with our hypothesis, activity in the teacher's ACC covaried with the PE values in the model. Additionally, activity in the teacher's insula and ventromedial prefrontal cortex covaried with the predicted value according to the student. Our findings highlight that the ACC signals PEs vicariously for others' erroneous predictions, when monitoring and instructing their learning. These results suggest that RL mechanisms, processed vicariously, may underpin and facilitate teaching behaviors. Copyright © 2015 Apps et al.

Bundling in Place: Translating the NGSS into Place-Based Earth-System Science Curricula

NASA Astrophysics Data System (ADS)

Semken, S. C.

2016-12-01

Bundling is the process of grouping Performance Expectations (PEs) from the Next Generation Science Standards (NGSS) into coherent units based on a defined topic, idea, question, or phenomenon. Bundling sorts the PEs for a given grade or grade band into a teachable narrative: a key stage in building curriculum, instruction, and assessment from the NGSS. To encourage and facilitate this, bundling guidelines have recently been released on the NGSS website (nextgenscience.org/glossary/bundlesbundling), and example bundles for different grade bands and disciplines are also being developed and posted there. According to these guidelines the iterative process of bundling begins with organization of PEs according to natural connections among them, and alignment of the three NGSS dimensions (Disciplinary Core Ideas, Cross-Cutting Concepts, and Science and Engineering Practices) that underpin each PE. Bundles are grouped by coherence and increasing complexity into courses, and courses into course sets that should encompass all PEs for a grade band. Bundling offers a natural way to translate the NGSS into highly contextualized curricula such as place-based (PB) teaching, which is situated in specific places or regions and focused on natural and cultural features, processes, phenomena, history, and challenges to sustainability therein. Attributes of place and our individual and collective connections to place (sense of place) directly inform PB curriculum, pedagogy, and assessment. PEs can be bundled by their relevance to these themes. Following the NGSS guidelines, I model the process for PB instruction by bundling PEs around the themes of Paleozoic geology and carbonate deposition and their relationships to mining and calcining of limestone in Anthropocene cement production for developing communities. The bundles integrate aspects of Earth history, the carbon cycle, mineral resources, climate change, and sustainability using specific local examples and narratives. They are designed for a hypothetical place-based high-school Earth-science course situated in the Greater American Southwest, but could be readily modified for another region with similar geology and resource use.

A neural network potential energy surface for the NaH2 system and dynamics studies on the H(2S) + NaH(X1Σ+) → Na(2S) + H2(X1Σg+) reaction.

PubMed

Wang, Shufen; Yuan, Jiuchuang; Li, Huixing; Chen, Maodu

2017-08-02

In order to study the dynamics of the reaction H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), a new potential energy surface (PES) for the ground state of the NaH 2 system is constructed based on 35 730 ab initio energy points. Using basis sets of quadruple zeta quality, multireference configuration interaction calculations with Davidson correction were carried out to obtain the ab initio energy points. The neural network method is used to fit the PES, and the root mean square error is very small (0.00639 eV). The bond lengths, dissociation energies, zero-point energies and spectroscopic constants of H 2 (X 1 Σ g + ) and NaH(X 1 Σ + ) obtained on the new NaH 2 PES are in good agreement with the experiment data. On the new PES, the reactant coordinate-based time-dependent wave packet method is applied to study the reaction dynamics of H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ), and the reaction probabilities, integral cross-sections (ICSs) and differential cross-sections (DCSs) are obtained. There is no threshold in the reaction due to the absence of an energy barrier on the minimum energy path. When the collision energy increases, the ICSs decrease from a high value at low collision energy. The DCS results show that the angular distribution of the product molecules tends to the forward direction. Compared with the LiH 2 system, the NaH 2 system has a larger mass and the PES has a larger well at the H-NaH configuration, which leads to a higher ICS value in the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction. Because the H( 2 S) + NaH(X 1 Σ + ) → Na( 2 S) + H 2 (X 1 Σ g + ) reaction releases more energy, the product molecules can be excited to a higher vibrational state.

Rovibrational spectra of ammonia. I. Unprecedented accuracy of a potential energy surface used with nonadiabatic corrections.

PubMed

Huang, Xinchuan; Schwenke, David W; Lee, Timothy J

2011-01-28

In this work, we build upon our previous work on the theoretical spectroscopy of ammonia, NH(3). Compared to our 2008 study, we include more physics in our rovibrational calculations and more experimental data in the refinement procedure, and these enable us to produce a potential energy surface (PES) of unprecedented accuracy. We call this the HSL-2 PES. The additional physics we include is a second-order correction for the breakdown of the Born-Oppenheimer approximation, and we find it to be critical for improved results. By including experimental data for higher rotational levels in the refinement procedure, we were able to greatly reduce our systematic errors for the rotational dependence of our predictions. These additions together lead to a significantly improved total angular momentum (J) dependence in our computed rovibrational energies. The root-mean-square error between our predictions using the HSL-2 PES and the reliable energy levels from the HITRAN database for J = 0-6 and J = 7∕8 for (14)NH(3) is only 0.015 cm(-1) and 0.020∕0.023 cm(-1), respectively. The root-mean-square errors for the characteristic inversion splittings are approximately 1∕3 smaller than those for energy levels. The root-mean-square error for the 6002 J = 0-8 transition energies is 0.020 cm(-1). Overall, for J = 0-8, the spectroscopic data computed with HSL-2 is roughly an order of magnitude more accurate relative to our previous best ammonia PES (denoted HSL-1). These impressive numbers are eclipsed only by the root-mean-square error between our predictions for purely rotational transition energies of (15)NH(3) and the highly accurate Cologne database (CDMS): 0.00034 cm(-1) (10 MHz), in other words, 2 orders of magnitude smaller. In addition, we identify a deficiency in the (15)NH(3) energy levels determined from a model of the experimental data.

[Pseudoexfoliation syndrome].

PubMed

Esmail, F

1991-05-01

The Frequency of the Pseudoexfoliation-Syndrom (= PES) was investigated about two months in a prospective study of 1069 patients in the university eye hospital of Zurich. 7.35% of these patients had a PES with or without glaucoma. Among the clinic patients there were 9.9% and among the policlinic patients 6.26%. All our patients were elder than 60 years old, 58.9% between 70-85 years. There were 33.37% men and 66.63% women. 33% of the PES-patients had a tension over 22 mmHg. 42.86% of the patients had the highest tension over 30 mmHg. 33.33% (= 26 patients) had a PES without glaucoma and 66.66% (= 52 patients) a PES with glaucoma. 56.42% of the patients (= 44 patients) had in one eye PES and 43.58% (34 patients) in both eyes. 9.61% (= 5 pat.) had an absolute PES-glaucoma in one eye.

Revealing pathways from payments for ecosystem services to socioeconomic outcomes

PubMed Central

Zhang, Jindong

2018-01-01

Payments for ecosystem services (PES) programs have been widely implemented as a promising tool to conserve ecosystems while facilitating socioeconomic development. However, the underlying pathways (or processes) through which PES programs affect socioeconomic outcomes remain elusive, and existing literature provides little guidance to quantify them. By integrating linkages among PES programs, livelihood activities, and socioeconomic outcomes, we develop a framework to reveal pathways from PES programs to socioeconomic outcomes. We empirically demonstrate the framework’s operationalization and uncover the pathways that lead to unexpected negative effects of two important PES programs on participating households’ income. With improved understanding of the pathways (for example, the programs decreased income through reducing crop production), we provide recommendations to enhance the PES programs’ outcomes in our demonstration site and beyond. Our study highlights the finding that elucidating the pathways from PES programs to their outcomes can help identify specific strategies to achieve ecosystem conservation and socioeconomic development simultaneously. PMID:29750187

Global Patterns in the Implementation of Payments for Environmental Services

PubMed Central

Ezzine-de-Blas, Driss; Wunder, Sven; Ruiz-Pérez, Manuel; Moreno-Sanchez, Rocio del Pilar

2016-01-01

Assessing global tendencies and impacts of conditional payments for environmental services (PES) programs is challenging because of their heterogeneity, and scarcity of comparative studies. This meta-study systematizes 55 PES schemes worldwide in a quantitative database. Using categorical principal component analysis to highlight clustering patterns, we reconfirm frequently hypothesized differences between public and private PES schemes, but also identify diverging patterns between commercial and non-commercial private PES vis-à-vis their service focus, area size, and market orientation. When do these PES schemes likely achieve significant environmental additionality? Using binary logistical regression, we find additionality to be positively influenced by three theoretically recommended PES ‘best design’ features: spatial targeting, payment differentiation, and strong conditionality, alongside some contextual controls (activity paid for and implementation time elapsed). Our results thus stress the preeminence of customized design over operational characteristics when assessing what determines the outcomes of PES implementation. PMID:26938065

Isolating Component Processes of Posterror Slowing with the Psychological Refractory Period Paradigm

ERIC Educational Resources Information Center

Steinhauser, Marco; Ernst, Benjamin; Ibald, Kevin W.

2017-01-01

Posterror slowing (PES) refers to an increased response time following errors. While PES has traditionally been attributed to control adjustments, recent evidence suggested that PES reflects interference. The present study investigated the hypothesis that control and interference represent 2 components of PES that differ with respect to their time…

Management of Postembolization Syndrome Following Hepatic Transarterial Chemoembolization for Primary or Metastatic Liver Cancer.

PubMed

Blackburn, Helen; West, Sandra

2016-01-01

Transarterial chemoembolization (TACE) is an established treatment in managing liver primary neoplasms or liver metastases. Postembolization syndrome (PES) is a common adverse event defined as fever without associated sepsis, pain in the right upper quadrant, and nausea and/or vomiting. This integrative review aims to identify effective management strategies for PES or one of its characterizing symptoms (fever, pain, and nausea and/or vomiting). Searches of electronic databases MEDLINE, EMBASE, and CINAHL were conducted. Fifteen articles were identified for inclusion. Seven addressed all symptoms of PES, and 8 studies focused on individual symptoms of PES. Interventions identified are intra-arterial lidocaine, oral and intravenous analgesics, steroids, wrist-ankle acupuncture, antibiotics, and 5-HT3 receptor antagonists. Findings are explicated according to individual symptoms of PES. Intra-arterial lidocaine, steroids, and a 5-HT3 receptor antagonist are found to offer potential benefit in the management of PES symptoms. A number of interventions have shown potential benefit in the management of PES. A systemic approach using combination therapy is necessary to effectively manage characterizing symptoms. Further research is needed to determine the impact of primary disease site, TACE technique, and chemotherapeutic agent on PES. Oncology nurses are uniquely placed to undertake thorough patient assessment after TACE and implement early intervention to effectively manage PES.

International Workshop on Microplasmas (5th)

DTIC Science & Technology

2010-04-14

Another fabric-treatment aplication of DCSBD discussed is the surface treatment of PES cords resulting in significant improvement of the adhesion to rubber...analyze small amount samples more efficiently, and to realize high performance mobile elemental analysis system, we have studied and developed high

An Accurate Potential Energy Surface for H2O

NASA Technical Reports Server (NTRS)

Schwenke, David W.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

1997-01-01

We have carried out extensive high quality ab initio electronic structure calculations of the ground state potential energy surface (PES) and dipole moment function (DMF) for H2O. A small adjustment is made to the PES to improve the agreement of line positions from theory and experiment. The theoretical line positions are obtained from variational ro-vibrational calculations using the exact kinetic energy operator. For the lines being fitted, the root-mean-square error was reduced from 6.9 to 0.08 /cm. We were then able to match 30,092 of the 30,117 lines from the HITRAN 96 data base to theoretical lines, and 80% of the line positions differed less than 0.1 /cm. About 3% of the line positions in the experimental data base appear to be incorrect. Theory predicts the existence of many additional weak lines with intensities above the cutoff used in the data base. To obtain results of similar accuracy for HDO, a mass dependent correction to the PH is introduced and is parameterized by simultaneously fitting line positions for HDO and D2O. The mass dependent PH has good predictive value for T2O and HTO. Nonadiabatic effects are not explicitly included. Line strengths for vibrational bands summed over rotational levels usually agree well between theory and experiment, but individual line strengths can differ greatly. A high temperature line list containing about 380 million lines has been generated using the present PES and DMF

Evaluation of polyethersulfone performance for the microextraction of polar chlorinated herbicides from environmental water samples.

PubMed

Prieto, Ailette; Rodil, Rosario; Quintana, José Benito; Cela, Rafael; Möder, Monika; Rodríguez, Isaac

2014-05-01

In this work, the suitability of bulk polyethersulfone (PES) for sorptive microextraction of eight polar, chlorinated phenoxy acids and dicamba from environmental water samples is assessed and the analytical features of the optimized method are compared to those reported for other microextraction techniques. Under optimized conditions, extractions were performed with samples (18 mL) adjusted at pH 2 and containing a 30% (w/v) of sodium chloride, using a tubular PES sorbent (1 cm length × 0.7 mm o.d., sorbent volume 8 µL). Equilibrium conditions were achieved after 3h of direct sampling, with absolute extraction efficiencies ranging from 39 to 66%, depending on the compound. Analytes were recovered soaking the polymer with 0.1 mL of ethyl acetate, derivatized and determined by gas chromatography-mass spectrometry (GC-MS). Achieved quantification limits (LOQs) varied between 0.005 and 0.073 ng mL(-1). After normalization with the internal surrogate (IS), the efficiency of the extraction was only moderately affected by the particular characteristics of different water samples (surface and sewage water); thus, pseudo-external calibration, using spiked ultrapure water solutions, can be used as quantification technique. The reduced cost of the PES polymer allowed considering it as a disposable sorbent, avoiding variations in the performance of the extraction due to cross-contamination problems and/or surface modification with usage. Copyright © 2014 Elsevier B.V. All rights reserved.

Stalking Higher Energy Conformers on the Potential Energy Surface of Charged Species.

PubMed

Brites, Vincent; Cimas, Alvaro; Spezia, Riccardo; Sieffert, Nicolas; Lisy, James M; Gaigeot, Marie-Pierre

2015-03-10

Combined theoretical DFT-MD and RRKM methodologies and experimental spectroscopic infrared predissociation (IRPD) strategies to map potential energy surfaces (PES) of complex ionic clusters are presented, providing lowest and high energy conformers, thresholds to isomerization, and cluster formation pathways. We believe this association not only represents a significant advance in the field of mapping minima and transition states on the PES but also directly measures dynamical pathways for the formation of structural conformers and isomers. Pathways are unraveled over picosecond (DFT-MD) and microsecond (RRKM) time scales while changing the amount of internal energy is experimentally achieved by changing the loss channel for the IRPD measurements, thus directly probing different kinetic and isomerization pathways. Demonstration is provided for Li(+)(H2O)3,4 ionic clusters. Nonstatistical formation of these ionic clusters by both direct and cascade processes, involving isomerization processes that can lead to trapping of high energy conformers along the paths due to evaporative cooling, has been unraveled.

Nature and potency interactions of the hydrogen bond through the NBO analysis for charge transfer complex between 2-amino-4-hydroxy-6-methylpyrimidine and 2,3-pyrazinedicarboxylic acid

NASA Astrophysics Data System (ADS)

Faizan, Mohd; Afroz, Ziya; Alam, Mohammad Jane; Bhat, Sheeraz Ahmad; Ahmad, Shabbir; Ahmad, Afaq

2018-05-01

The intermolecular interactions in complex formation between 2-amino-4-hydroxy-6-methylpyrimidine (AHMP) and 2,3-pyrazinedicarboxylicacid (PDCA) have been explored using density functional theory calculations. The isolated 1:1 molecular geometry of proton transfer (PT) complex between AHMP and PDCA has been optimized on a counterpoise corrected potential energy surface (PES) at DFT-B3LYP/6-31G(d,p) level of theory in the gaseous phase. Further, the formation of hydrogen bonded charge transfer (HBCT) complex between PDCA and AHMP has been also discussed. PT energy barrier between two extremes is calculated using potential energy surface (PES) scan by varying bond length. The intermolecular interactions have been analyzed from theoretical perspective of natural bond orbital (NBO) analysis. In addition, the interaction energy between molecular fragments involved in the complex formation has been also computed by counterpoise procedure at same level of theory.

Tobacco smoking is associated with psychotic experiences in the general population of South London.

PubMed

Bhavsar, V; Jauhar, S; Murray, R M; Hotopf, M; Hatch, S L; McNeill, A; Boydell, J; MacCabe, J H

2018-01-01

The association between cigarette smoking and psychosis remains unexplained, but could relate to causal effects in both directions, confounding by socioeconomic factors, such as ethnicity, or use of other substances, including cannabis. Few studies have evaluated the association between cigarettes and psychotic experiences (PEs) in diverse, inner-city populations, or relationships with number of cigarettes consumed. We assessed associations and dose-response relationships between cigarette smoking and PEs in a cross-sectional survey of household residents (n = 1680) in South East London, using logistic regression to adjust for cannabis use, other illicit substances, and socioeconomic factors, including ethnicity. We found association between any PEs and daily cigarette smoking, which remained following adjustment for age, gender, ethnicity, cannabis and use of illicit stimulant drugs (fully adjusted odds ratio 1.47, 95% confidence interval 1.01-2.15). Fully adjusted estimates for the association, and with number of PEs, increased with number of cigarettes smoked daily, implying a dose-response effect (p = 0.001 and <0.001, respectively). Odds of reporting any PEs in ex-smokers were similar to never-smokers. In this diverse epidemiological sample, association between smoking and PEs was not explained by confounders such as cannabis or illicit drugs. Daily cigarette consumption showed a dose-response relationship with the odds of reporting PEs, and of reporting a greater number of PEs. There was no difference in odds of reporting PEs between ex-smokers and never-smokers, raising the possibility that the increase in PEs associated with smoking may be reversible.

The Play Experience Scale: development and validation of a measure of play.

PubMed

Pavlas, Davin; Jentsch, Florian; Salas, Eduardo; Fiore, Stephen M; Sims, Valerie

2012-04-01

A measure of play experience in video games was developed through literature review and two empirical validation studies. Despite the considerable attention given to games in the behavioral sciences, play experience remains empirically underexamined. One reason for this gap is the absence of a scale that measures play experience. In Study 1, the initial Play Experience Scale (PES) was tested through an online validation that featured three different games (N = 203). In Study 2, a revised PES was assessed with a serious game in the laboratory (N = 77). Through principal component analysis of the Study 1 data, the initial 20-item PES was revised, resulting in the 16-item PES-16. Study 2 showed the PES-16 to be a robust instrument with the same patterns of correlations as in Study 1 via (a) internal consistency estimates, (b) correlations with established scales of motivation, (c) distributions of PES-16 scores in different game conditions, and (d) examination of the average variance extracted of the PES and the Intrinsic Motivation Scale. We suggest that the PES is appropriate for use in further validation studies. Additional examinations of the scale are required to determine its applicability to other contexts and its relationship with other constructs. The PES is potentially relevant to human factors undertakings involving video games, including basic research into play, games, and learning; prototype testing; and exploratory learning studies.

Parallel discrete-event simulation schemes with heterogeneous processing elements.

PubMed

Kim, Yup; Kwon, Ikhyun; Chae, Huiseung; Yook, Soon-Hyung

2014-07-01

To understand the effects of nonidentical processing elements (PEs) on parallel discrete-event simulation (PDES) schemes, two stochastic growth models, the restricted solid-on-solid (RSOS) model and the Family model, are investigated by simulations. The RSOS model is the model for the PDES scheme governed by the Kardar-Parisi-Zhang equation (KPZ scheme). The Family model is the model for the scheme governed by the Edwards-Wilkinson equation (EW scheme). Two kinds of distributions for nonidentical PEs are considered. In the first kind computing capacities of PEs are not much different, whereas in the second kind the capacities are extremely widespread. The KPZ scheme on the complex networks shows the synchronizability and scalability regardless of the kinds of PEs. The EW scheme never shows the synchronizability for the random configuration of PEs of the first kind. However, by regularizing the arrangement of PEs of the first kind, the EW scheme is made to show the synchronizability. In contrast, EW scheme never shows the synchronizability for any configuration of PEs of the second kind.

Hydrophilicity and antifouling property of membrane materials from cellulose acetate/polyethersulfone in DMAc.

PubMed

Sun, Zhonghua; Chen, Fushan

2016-10-01

In this study, cellulose acetate (CA) was blended with polyethersulfone (PES) to endow the ultrafiltration membrane with the improved hydrophilicity and antifouling property by using N,N-dimethylacetamide (DMAc) as the solvent. The effects of blend composition and evaporation time on the mechanical strength and pure water flux were investigated. It was found that the optimal composition of the casting solution was: 18wt% (PES), 4wt% (Polyvinylpyrrolidone K30), 3wt% (CA) and 20s (Evaporation time). The characteristics of CA-PES blend membranes were investigated through the methods of contact angle goniometer, antifouling property, compatibility, thermo gravimetric analysis and SEM. The results showed that the hydrophilicity and antifouling property of CA-PES ultrafiltration membranes were enhanced in comparison with the pure PES membranes. The CA-PES membranes exhibited semi-compatibility and good thermal stability below 270°C. This study provided a potential industrial application prospect of CA-PES membranes prepared in DMAc. Copyright © 2016 Elsevier B.V. All rights reserved.

A facile approach toward multifunctional polyethersulfone membranes via in situ cross-linked copolymerization.

PubMed

Sun, Chuangchao; Ji, Haifeng; Qin, Hui; Nie, Shengqiang; Zhao, Weifeng; Zhao, Changsheng

2015-01-01

In this study, multifunctional polyethersulfone (PES) membranes are prepared via in situ cross-linked copolymerization coupled with a liquid-liquid phase separation technique. Acrylic acid (AA) and N-vinylpyrrolidone (VP) are copolymerized in PES solution, and the solution is then directly used to prepare PES membranes. The infrared and X-ray photoelectron spectroscopy testing, scanning electron microscopy, and water contact angle measurements confirm the successful modification of pristine PES membrane. Protein adsorption, platelet adhesion, plasma recalcification time, and activated partial thromboplastin time assays convince that the modified PES membranes have a better biocompatibility than pristine PES membrane. In addition, the modified membranes showed good protein antifouling property and significant adsorption property of cationic dye. The loading of Ag nanoparticles into the modified membranes endows the composite membranes with antibacterial activity.

The association between childhood adversities and subsequent first onset of psychotic experiences: a cross-national analysis of 23 998 respondents from 17 countries.

PubMed

McGrath, J J; McLaughlin, K A; Saha, S; Aguilar-Gaxiola, S; Al-Hamzawi, A; Alonso, J; Bruffaerts, R; de Girolamo, G; de Jonge, P; Esan, O; Florescu, S; Gureje, O; Haro, J M; Hu, C; Karam, E G; Kovess-Masfety, V; Lee, S; Lepine, J P; Lim, C C W; Medina-Mora, M E; Mneimneh, Z; Pennell, B E; Piazza, M; Posada-Villa, J; Sampson, N; Viana, M C; Xavier, M; Bromet, E J; Kendler, K S; Kessler, R C

2017-05-01

Although there is robust evidence linking childhood adversities (CAs) and an increased risk for psychotic experiences (PEs), little is known about whether these associations vary across the life-course and whether mental disorders that emerge prior to PEs explain these associations. We assessed CAs, PEs and DSM-IV mental disorders in 23 998 adults in the WHO World Mental Health Surveys. Discrete-time survival analysis was used to investigate the associations between CAs and PEs, and the influence of mental disorders on these associations using multivariate logistic models. Exposure to CAs was common, and those who experienced any CAs had increased odds of later PEs [odds ratio (OR) 2.3, 95% confidence interval (CI) 1.9-2.6]. CAs reflecting maladaptive family functioning (MFF), including abuse, neglect, and parent maladjustment, exhibited the strongest associations with PE onset in all life-course stages. Sexual abuse exhibited a strong association with PE onset during childhood (OR 8.5, 95% CI 3.6-20.2), whereas Other CA types were associated with PE onset in adolescence. Associations of other CAs with PEs disappeared in adolescence after adjustment for prior-onset mental disorders. The population attributable risk proportion (PARP) for PEs associated with all CAs was 31% (24% for MFF). Exposure to CAs is associated with PE onset throughout the life-course, although sexual abuse is most strongly associated with childhood-onset PEs. The presence of mental disorders prior to the onset of PEs does not fully explain these associations. The large PARPs suggest that preventing CAs could lead to a meaningful reduction in PEs in the population.

Risk factors for drug-resistant pathogens in immunocompetent patients with pneumonia: Evaluation of PES pathogens.

PubMed

Ishida, Tadashi; Ito, Akihiro; Washio, Yasuyoshi; Yamazaki, Akio; Noyama, Maki; Tokioka, Fumiaki; Arita, Machiko

2017-01-01

The new acronym, PES pathogens (Pseudomonas aeruginosa, Enterobacteriaceae extended-spectrum beta-lactamase-positive, and methicillin-resistant Staphylococcus aureus), was recently proposed to identify drug-resistant pathogens associated with community-acquired pneumonia. To evaluate the risk factors for antimicrobial-resistant pathogens in immunocompetent patients with pneumonia and to validate the role of PES pathogens. A retrospective analysis of a prospective observational study of immunocompetent patients with pneumonia between March 2009 and June 2015 was conducted. We clarified the risk factors for PES pathogens. Of the total 1559 patients, an etiological diagnosis was made in 705 (45.2%) patients. PES pathogens were identified in 51 (7.2%) patients, with 53 PES pathogens (P. aeruginosa, 34; ESBL-positive Enterobacteriaceae, 6; and MRSA, 13). Patients with PES pathogens had tendencies toward initial treatment failure, readmission within 30 days, and a prolonged hospital stay. Using multivariate analysis, female sex (adjusted odds ratio [AOR] 1.998, 95% confidence interval [CI] 1.047-3.810), admission within 90 days (AOR 2.827, 95% CI 1.250-6.397), poor performance status (AOR 2.380, 95% CI 1.047-5.413), and enteral feeding (AOR 5.808, 95% CI 1.813-18.613) were independent risk factors for infection with PES pathogens. The area under the receiver operating characteristics curve for the risk factors was 0.66 (95% CI 0.577-0.744). We believe the definition of PES pathogens is an appropriate description of drug-resistant pathogens associated with pneumonia in immunocompetent patients. The frequency of PES pathogens is quite low. However, recognition is critical because they can cause refractory pneumonia and different antimicrobial treatment is required. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Proto-experiences and subjective experiences: classical and quantum concepts.

PubMed

Vimal, Ram Lakhan Pandey

2008-03-01

Deterministic reductive monism and non-reductive substance dualism are two opposite views for consciousness, and both have serious problems. An alternative view is needed. For this, we hypothesize that strings or elementary particles (fermions and bosons) have two aspects: (i) elemental proto-experiences (PEs) as phenomenal aspect, and (ii) mass, charge, and spin as material aspect. Elemental PEs are hypothesized to be the properties of elementary particles and their interactions, which are composed of irreducible fundamental subjective experiences (SEs)/PEs that are in superimposed form in elementary particles and in their interactions. Since SEs/PEs are superimposed, elementary particles are not specific to any SE/PE; they (and all inert matter) are carriers of SEs/PEs, and hence, appear as non-experiential material entities. Furthermore, our hypothesis is that matter and associated elemental PEs co-evolved and co-developed into neural-nets and associated neural-net PEs (neural Darminism), respectively. The signals related to neural PEs interact in a neural-net and neural-net PEs emerges from random process of self-organization. The neural-net PEs are a set of SEs embedded in the neural-net by a non-computational or non-algorithmic process. The non-specificity of elementary particles is transformed into the specificity of neural-nets by neural Darwinism. The specificity of SEs emerges when feedforward and feedback signal interacts in the neuropil and are dependent on wakefulness (i.e., activation) attention, re-entry between neural populations, working memory, stimulus at above threshold, and neural net PE signals. This PE-SE framework integrates reductive and non-reductive views, complements the existing models, bridges the explanatory gaps, and minimizes the problem of causation.

The association between childhood adversities and subsequent first onset of psychotic experiences: a cross-national analysis of 23,998 respondents from 17 countries

PubMed Central

McGrath, J. J.; McLaughlin, K. A.; Saha, S.; Aguilar-Gaxiola, S.; Al-Hamzawi, A.; Alonso, J.; Bruffaerts, R.; de Girolamo, G.; de Jonge, P.; Esan, O.; Florescu, S.; Gureje, O.; Haro, J. M.; Hu, C.; Karam, E. G.; Kovess-Masfety, V.; Lee, S.; Lepine, J.; Lim, C. C. W.; Medina-Mora, M. E.; Mneimneh, Z.; Pennell, B.; Piazza, M.; Posada-Villa, J.; Sampson, N.; Viana, M. C.; Xavier, M.; Bromet, E. J.; Kendler, K. S.; Kessler, R. C.

2017-01-01

Background Although there is robust evidence linking childhood adversities (CAs) and an increased risk for psychotic experiences (PEs), little is known about whether these associations vary across the life-course and whether mental disorders that emerge prior to PEs explain these associations. Methods We assessed CAs, PEs and DSM-IV mental disorders in 23,998 adults in the WHO World Mental Health Surveys. Discrete-time survival analysis was used to investigate the associations between CAs and PEs, and the influence of mental disorders on these associations using multivariate logistic models. Results Exposure to CAs was common, and those who experienced any CAs had increased odds of later PEs (OR =2.3, 95%CI=1.9–2.6). CAs reflecting maladaptive family functioning (MFF), including abuse, neglect, and parent maladjustment, exhibited the strongest associations with PE onset in all life-course stages. Sexual abuse exhibited a strong association with PE onset during childhood (OR= 8.5, 95%CI=3.6–20.2), whereas other CA types were associated with PE onset in adolescence. Associations of Other CAs with PEs disappeared in adolescence after adjustment for prior-onset mental disorders. The population attributable risk proportion (PARP) for PEs associated with all CAs was 31% (24% for MFF). Conclusions Exposure to CAs is associated with PE onset throughout the life-course, although sexual abuse is most strongly associated with childhood onset PEs. The presence of mental disorders prior to the onset of PEs does not fully explain these associations. The large PARPs suggest that preventing CAs could lead to a meaningful reduction in PEs in the population. PMID:28065209

Adjunctive functional pharyngeal electrical stimulation reverses swallowing disability after brain lesions.

PubMed

Jayasekeran, Vanoo; Singh, Salil; Tyrrell, Pippa; Michou, Emilia; Jefferson, Samantha; Mistry, Satish; Gamble, Ed; Rothwell, John; Thompson, David; Hamdy, Shaheen

2010-05-01

Oropharyngeal dysphagia is an important disability that occurs after stroke; it contributes to aspiration pneumonia and death, and current modalities for rehabilitation of dysphagia have uncertain efficacy. We therefore examined the role of pharyngeal electrical stimulation (PES) in expediting human swallowing recovery after experimental (virtual) and actual (stroke) brain lesions. First, healthy subjects (n = 13) were given 1-Hz repetitive transcranial magnetic stimulation to induce a unilateral virtual lesion in pharyngeal motor cortex followed by active or sham (control) PES. Motor-evoked potentials and swallow accuracy were recorded before and after the lesion to assess PES response. Thereafter, 50 acute dysphagic stroke patients underwent either a dose-response study, to determine optimal parameters for PES (n = 22), or were assigned randomly to groups given either active or sham (control) PES (n = 28). The primary end point was the reduction of airway aspiration at 2 weeks postintervention. In contrast to sham PES, active PES reversed the cortical suppression induced by the virtual lesion (F(7,70) = 2.7; P = .015) and was associated with improvement in swallowing behavior (F(3,42) = 5; P = .02). After stroke, 1 PES treatment each day (U = 8.0; P = .043) for 3 days (U = 10.0) produced improved airway protection compared with controls (P = .038). Active PES also reduced aspiration (U = 54.0; P = .049), improved feeding status (U = 58.0; P = .040), and resulted in a shorter time to hospital discharge (Mantel-Cox log-rank test, P = 0.038). This pilot study of PES confirms that it is a safe neurostimulation intervention that reverses swallowing disability after virtual lesion or stroke. Copyright 2010 AGA Institute. Published by Elsevier Inc. All rights reserved.

Metabonomics by proton nuclear magnetic resonance in human pleural effusions: A route to discriminate between benign and malignant pleural effusions and to target small molecules as potential cancer biomarkers.

PubMed

Zennaro, Lucio; Vanzani, Paola; Nicolè, Lorenzo; Cappellesso, Rocco; Fassina, Ambrogio

2017-05-01

Cytopathology is a noninvasive and cost-effective method for detecting cancer cells in pleural effusions (PEs), although in many cases, the diagnostic performance is hindered by the paucity of significant cells or the lack of clear morphological criteria. This study presents the results of an omics approach to improving the diagnostic performance of PE cytology. Metabolic profiling with proton nuclear magnetic resonance ( 1 H-NMR) was performed for 92 PEs (44 malignant cases of 8 different cancers and 48 benign cases of 7 nonneoplastic conditions). Light's criteria were used to further classify PEs as transudates or exudates, and 1 H-NMR spectroscopy was used to differentiate malignant pleural effusions (mPEs) from benign pleural effusions (bPEs). 1 H-NMR metabolic analysis showed clearly different spectra for mPEs and bPEs in the regions of the signals due to lipids, branched amino acids, and lactate, which were increased in mPEs. Transudates and exudates in bPEs were differentiated as well on the basis of the 1 H-NMR signals from lipids and lipoproteins, which were increased in exudates. Subject to validation in further larger studies, 1 H-NMR metabonomics could be an effective and reliable ancillary tool for PE investigations and diagnoses. Cancer Cytopathol 2017;125:341-348. © 2017 American Cancer Society. © 2017 American Cancer Society.

The PAPI-1 pathogenicity island-encoded small RNA PesA influences Pseudomonas aeruginosa virulence and modulates pyocin S3 production

PubMed Central

Ferrara, Silvia; Falcone, Marilena; Macchi, Raffaella; Bragonzi, Alessandra; Girelli, Daniela; Cariani, Lisa; Cigana, Cristina

2017-01-01

Small non-coding RNAs (sRNAs) are post-transcriptional regulators of gene expression that have been recognized as key contributors to bacterial virulence and pathogenic mechanisms. In this study, we characterized the sRNA PesA of the opportunistic human pathogen Pseudomonas aeruginosa. We show that PesA, which is transcribed within the pathogenicity island PAPI-1 of P. aeruginosa strain PA14, contributes to P. aeruginosa PA14 virulence. In fact, pesA gene deletion resulted in a less pathogenic strain, showing higher survival of cystic fibrosis human bronchial epithelial cells after infection. Moreover, we show that PesA influences positively the expression of pyocin S3 whose genetic locus comprises two structural genes, pyoS3A and pyoS3I, encoding the killing S3A and the immunity S3I proteins, respectively. Interestingly, the deletion of pesA gene results in increased sensitivity to UV irradiation and to the fluoroquinolone antibiotic ciprofloxacin. The degree of UV sensitivity displayed by the PA14 strain lacking PesA is comparable to that of a strain deleted for pyoS3A-I. These results suggest an involvement of pyocin S3 in DNA damage repair and a regulatory role of PesA on this function. PMID:28665976

Upper airway resistance syndrome. Central electroencephalographic power and changes in breathing effort.

PubMed

Black, J E; Guilleminault, C; Colrain, I M; Carrillo, O

2000-08-01

Upper airway resistance syndrome (UARS) is defined by excessive daytime sleepiness and tiredness, and is associated with increased breathing effort. Its polygraphic features involve progressive increases in esophageal pressure (Pes), terminated by arousal (AR) as defined by the American Sleep Disorders Association (ASDA). With the arousal there is an abrupt decrease in Pes, called Pes reversal. However, Pes reversal can be seen without the presence of an AR. We performed spectral analysis on electroencephalographic data from a central lead for both AR and nonarousal (N-AR) events obtained from 15 UARS patients (eight men and seven women). Delta band activity was increased before and surrounding Pes reversal regardless of the presence or absence of AR. In the period after Pes reversal, alpha, sigma, and beta activity showed a greater increase in AR events than in N-AR events. The Pes measures were identical leading up to the point of reversal, but showed a longer-lasting and significantly greater decrease in respiratory effort after an AR. The data indicate that substantial electroencephalographic changes can be identified in association with Pes events, even when ARs cannot be detected according to standard criteria; however, visually identifiable electroencephalographic arousals clearly have a greater impact on ongoing inspiratory effort.

Long-range electron transfer in a model for DNA

NASA Astrophysics Data System (ADS)

Endres, R. G.; Cox, D. L.

2001-03-01

Long-range electron transfer (ET) between well separated donor (D) and acceptor (A) sites through quantum mechanical tunneling is essential to many biological processes like respiration, photosynthesis and possibly DNA repair and damage. We are investigating the distance dependence of the electronic transition matrix element H_DA and hence of the electron transfer rate in a model for DNA. Fluorescence quenching in DNA at D-A distances of 40 Åand more suggests ET with an unusually high decay length β-1 of order 10 Å (S.O.Kelley and J.K.Barton, in:Metal Ions in Biological Systems), A.Sigel and H.Sigel, Eds., Marcel Dekker, New York, Vol.36, 1999. Assuming strong electron interactions on the D complex and suitable energetics, this could be explained by formation of a many electron Kondo boundstate. We obtain H_DA from the splitting between the two lowest adiabatic electronic eigenenergies, which constitute the potential energy surfaces (PES) of the nuclear motion in lowest order Born-Oppenheimer approximation. The PES are constructed by coupling D and A to local breathing modes and by making a semi-analytical variational ansatz for the adiabatic eigenstates. The results from the PES are compared with results from the Mulliken-Hush algorithm.

Collisional excitation of ArH+ by hydrogen atoms

NASA Astrophysics Data System (ADS)

Dagdigian, Paul J.

2018-06-01

The rotational excitation of the 36ArH+ ion in collisions with hydrogen atoms is investigated in this work. The potential energy surface (PES) describing the 36ArH+-H interaction, with the ion bond length r fixed at the average of r over the radial v = 0 vibrational state distribution, was obtained with a coupled cluster method that included single, double, and (perturbatively) triple excitations [RCCSD(T)]. A deep minimum (De = 3135 cm-1) in the PES was found in linear H-ArH+ geometry at an ion-atom separation Re = 4.80a0. Energy-dependent cross-sections and rate coefficients as a function of temperature for this collision pair were computed in close-coupling (CC) calculations. Since the PES possesses a deep well, this is a good system to test the performance of the quantum statistical (QS) method developed by Manolopoulos and co-workers as a more efficient method to compute the cross-sections. Good agreement was found between rate coefficients obtained by the CC and QS methods at several temperatures. In a simple application, the excitation of ArH+ is simulated for conditions under which this ion is observed in absorption.

Efficient sampling over rough energy landscapes with high barriers: A combination of metadynamics with integrated tempering sampling.

PubMed

Yang, Y Isaac; Zhang, Jun; Che, Xing; Yang, Lijiang; Gao, Yi Qin

2016-03-07

In order to efficiently overcome high free energy barriers embedded in a complex energy landscape and calculate overall thermodynamics properties using molecular dynamics simulations, we developed and implemented a sampling strategy by combining the metadynamics with (selective) integrated tempering sampling (ITS/SITS) method. The dominant local minima on the potential energy surface (PES) are partially exalted by accumulating history-dependent potentials as in metadynamics, and the sampling over the entire PES is further enhanced by ITS/SITS. With this hybrid method, the simulated system can be rapidly driven across the dominant barrier along selected collective coordinates. Then, ITS/SITS ensures a fast convergence of the sampling over the entire PES and an efficient calculation of the overall thermodynamic properties of the simulation system. To test the accuracy and efficiency of this method, we first benchmarked this method in the calculation of ϕ - ψ distribution of alanine dipeptide in explicit solvent. We further applied it to examine the design of template molecules for aromatic meta-C-H activation in solutions and investigate solution conformations of the nonapeptide Bradykinin involving slow cis-trans isomerizations of three proline residues.

Efficient sampling over rough energy landscapes with high barriers: A combination of metadynamics with integrated tempering sampling

NASA Astrophysics Data System (ADS)

Yang, Y. Isaac; Zhang, Jun; Che, Xing; Yang, Lijiang; Gao, Yi Qin

2016-03-01

In order to efficiently overcome high free energy barriers embedded in a complex energy landscape and calculate overall thermodynamics properties using molecular dynamics simulations, we developed and implemented a sampling strategy by combining the metadynamics with (selective) integrated tempering sampling (ITS/SITS) method. The dominant local minima on the potential energy surface (PES) are partially exalted by accumulating history-dependent potentials as in metadynamics, and the sampling over the entire PES is further enhanced by ITS/SITS. With this hybrid method, the simulated system can be rapidly driven across the dominant barrier along selected collective coordinates. Then, ITS/SITS ensures a fast convergence of the sampling over the entire PES and an efficient calculation of the overall thermodynamic properties of the simulation system. To test the accuracy and efficiency of this method, we first benchmarked this method in the calculation of ϕ - ψ distribution of alanine dipeptide in explicit solvent. We further applied it to examine the design of template molecules for aromatic meta-C—H activation in solutions and investigate solution conformations of the nonapeptide Bradykinin involving slow cis-trans isomerizations of three proline residues.

Efficient sampling over rough energy landscapes with high barriers: A combination of metadynamics with integrated tempering sampling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Y. Isaac; Zhang, Jun; Che, Xing

2016-03-07

In order to efficiently overcome high free energy barriers embedded in a complex energy landscape and calculate overall thermodynamics properties using molecular dynamics simulations, we developed and implemented a sampling strategy by combining the metadynamics with (selective) integrated tempering sampling (ITS/SITS) method. The dominant local minima on the potential energy surface (PES) are partially exalted by accumulating history-dependent potentials as in metadynamics, and the sampling over the entire PES is further enhanced by ITS/SITS. With this hybrid method, the simulated system can be rapidly driven across the dominant barrier along selected collective coordinates. Then, ITS/SITS ensures a fast convergence ofmore » the sampling over the entire PES and an efficient calculation of the overall thermodynamic properties of the simulation system. To test the accuracy and efficiency of this method, we first benchmarked this method in the calculation of ϕ − ψ distribution of alanine dipeptide in explicit solvent. We further applied it to examine the design of template molecules for aromatic meta-C—H activation in solutions and investigate solution conformations of the nonapeptide Bradykinin involving slow cis-trans isomerizations of three proline residues.« less

A new DFT approach to model small polarons in oxides with proper account for long-range polarization

NASA Astrophysics Data System (ADS)

Kokott, Sebastian; Levchenko, Sergey V.; Scheffler, Matthias; Theory Department Team

In this work, we address two important challenges in the DFT description of small polarons (excess charges localized within one unit cell): sensitivity to the errors in exchange-correlation (XC) treatment and finite-size effects in supercell calculations. The polaron properties are obtained using a modified neutral potential-energy surface (PES). Using the hybrid HSE functional and considering the whole range 0 <= α <= 1 , we show that the modified PES model significantly reduces the dependence of the polaron level and binding energy in MgO and TiO2 on the XC functional. It does not eliminate the dependence on supercell size. Based on Pekar's model, we derive the proper long-range behavior of the polaron and a finite-size correction that allows to obtain the polaron properties in the dilute limit (tested for supercells containing up to 1,000 atoms). The developed approach reduces drastically the computational time for exploring the polaron PES, and gives a consistent description of polarons for the whole range of α. It allowed us to find a self-trapped hole in MgO that is noticeably more stable than reported previously. partially supported by UniCat (Deutsche Forschungsgemeinschaft).

Effect of Gold Nanorod Surface Chemistry on Cellular Interactions In Vitro

DTIC Science & Technology

2010-09-01

properties of GNRs on cells. Previous studies on the cytotoxicity of various nanoparticles indicated that surface chemistry has a strong influence on cell...supplemented with 10% fetal bovine serum (FBS, ATCC) and 1% penicillin/streptomycin (pen/strep, Sigma). For nanoparticle exposure, media was supplemented...reagent ( phenazine ethosulfate; PES). Metabolically active cells reduce the MTS compound into a colored formazan product that is soluble in tissue

Relationship Between Secondary-Electron Yield and Structure of Polycrystalline Diamond Prepared Under Different Methane Concentrations

NASA Astrophysics Data System (ADS)

Wei, Kongting; Wu, Shengli; Wei, Qiang; Zheng, Pu; Hu, Wenbo; Wang, Hongxing

2018-05-01

To understand the mechanism of electron transport and escape to vacuum of polycrystalline chemical-vapor-deposited diamond films prepared under different methane (CH4) concentrations, the secondary electron yield (SEY) δ as a function of primary electron (PE) energy E p has been investigated. The δ-E p curves exhibited different features for films synthesized under different CH4 concentrations, and the highest SEY was obtained when the CH4 concentration was 2%. A physical model was used to compute the key parameters of escape depth λ s and surface factor f 0·A s. The results indicated that λ s is closely related to the crystal quality of the diamond film, with diamond of high quality having larger λ s, while the surface factor f 0·A s is mainly determined by the surface morphology, which is associated with the surface roughness of the film. Using the above model, the SEY as a function of varying λ s and f 0·A s was also calculated; the results suggested that f 0·A s plays a key role in determining SEY for low-energy PEs, especially for energies < 500 eV, while the SEY is affected by both λ s and f 0·A s for high-energy PEs.

Pes cavus and hereditary neuropathies: when a relationship should be suspected.

PubMed

Piazza, S; Ricci, G; Caldarazzo Ienco, E; Carlesi, C; Volpi, L; Siciliano, G; Mancuso, M

2010-12-01

The hereditary peripheral neuropathies are a clinically and genetically heterogeneous group of diseases of the peripheral nervous system. Foot deformities, including the common pes cavus, but also hammer toes and twisting of the ankle, are frequently present in patients with hereditary peripheral neuropathy, and often represent one of the first signs of the disease. Pes cavus in hereditary peripheral neuropathies is caused by imbalance between the intrinsic muscles of the foot and the muscles of the leg. Accurate clinical evaluation in patients with pes cavus is necessary to exclude or confirm the presence of peripheral neuropathy. Hereditary peripheral neuropathies should be suspected in those cases with bilateral foot deformities, in the presence of family history for pes cavus and/or gait impairment, and in the presence of neurological symptoms or signs, such as distal muscle hypotrophy of limbs. Herein, we review the hereditary peripheral neuropathies in which pes cavus plays a key role as a "spy sign," discussing the clinical and molecular features of these disorders to highlight the importance of pes cavus as a helpful clinical sign in these rare diseases.

Protein-enhanced soups: a consumer-accepted food for increasing dietary protein provision among older adults.

PubMed

Donahue, Elizabeth; Crowe, Kristi Michele; Lawrence, Jeannine

2015-02-01

Protein-enhanced soups (PES) may improve protein intake among older adults. This study examined sensory attributes (aroma, texture, taste, and overall acceptability) and preferences of PES (chicken noodle and cheddar broccoli) compared with flavor-matched control soups (FCS) among older adults (≥65 years) and evaluated dietary profile changes of a standard menu based on the substitution of one PES serving/d for a standard soup. Modified paired preference tests and 5-point facial hedonic scales were administered to participants (n = 44). No significant differences in sensory attributes between either PES compared with FCS were identified, but significant gender- and age-related differences (p < 0.05) were observed. About Sixty-one percent of participants preferred protein-enhanced chicken noodle soup while only 38% preferred protein-enhanced cheddar broccoli soup to their respective FCS. Substituting one PES serving for one non-fortified soup serving per day resulted in significantly higher (p < 0.001) protein profile. Results suggest that all attributes of PES were consistent with sensory expectations and PES substitution could improve protein provision.

Development of modified-release dosage forms containing loratadine and pseudoephedrine sulfate.

PubMed

Sznitowska, Małgorzata; Cal, Krzysztof; Kupiec, Katarzyna

2004-12-01

Pseudoephedrine sulfate (PES) is a short-acting sympathomimetic amine and decongestant. Loratadine (L) is a long-acting antihistamine, H1 blocker. These drugs administered together provide relief from a whole range of rhinitis (hay fever) symptoms. Combination of both drugs is available in the form of sugar-coated modified-release tablets Clarinase (Schering-Plough). In this product, 5 mg of L and 60 mg of PES is present in the sugar-coating layer ready for an immediate release, and the rest of PES (60 mg) is incorporated in the extended-release core of the tablet. This enables fast as well as prolonged release of PES over 6-8 h. Because the sugar coating technologies are troublesome and rarely used nowadays, the aim of this study was to develop alternative oral dosage forms containing L (5 mg) and PES (120 mg). It was assumed that, similarly to the original product, the total dose of L and the half dose of PES should be released during 1 h and the remaining dose of PES ought to be gradually released for up to 8 h.

HgCdTe Surface and Defect Study Program.

DTIC Science & Technology

1985-01-01

LWIR (x 0.2) HgCdTe surface will be so depleted in cations that the resulting equivajqnt alloy will be metallic or semimetallic (x < 0.17), and hence...spectrometry (PES) results on MWIR are applicable to the first 10 to 15A of the surface. The point here is that LWIR material may respond to passivation...processes to produce a fundamentally different result than does MWIR material, and LWIR should in fact be treated as a completely different material. These

Nuclear quantum effects on adsorption of H 2 and isotopologues on metal ions

DOE PAGES

Savchenko, Ievgeniia; Gu, Bing; Heine, Thomas; ...

2017-01-03

The nuclear quantum effects on the zero-point energy (ZPE), influencing adsorption of Hmore » $$_2$$ and isotopologues on metal ions, are examined in this study using normal mode analysis of ab initio electronic structure results for complexes with 17 metal cations. To estimate for the anharmonicity, a nuclear wavepacket dynamics on the ground state electronic potential energy surfaces (PES) have been employed for complexes of Li$^+$ and Cu$$^{+2}$$ with H$$_2$$, D$$_2$$, HD. The dynamics analysis shows that incorporation of the PES anharmonicity changes the ZPE by up to 9%. Finally, the lightest metallic nuclei, Li and Be, are found to be the most 'quantum'. The largest selectivity in adsorption is predicted for Cu, Ni and Co ions.« less

Anharmonic frequencies of CX2Y2 (X, Y = O, N, F, H, D) isomers and related systems obtained from vibrational multiconfiguration self-consistent field theory.

PubMed

Pfeiffer, Florian; Rauhut, Guntram

2011-10-13

Accurate anharmonic frequencies are provided for molecules of current research, i.e., diazirines, diazomethane, the corresponding fluorinated and deuterated compounds, their dioxygen analogs, and others. Vibrational-state energies were obtained from state-specific vibrational multiconfiguration self-consistent field theory (VMCSCF) based on multilevel potential energy surfaces (PES) generated from explicitly correlated coupled cluster, CCSD(T)-F12a, and double-hybrid density functional calculations, B2PLYP. To accelerate the vibrational structure calculations, a configuration selection scheme as well as a polynomial representation of the PES have been exploited. Because experimental data are scarce for these systems, many calculated frequencies of this study are predictions and may guide experiments to come.

Surface and bulk electronic structures of unintentionally and Mg-doped In0.7Ga0.3N epilayer by hard X-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Imura, Masataka; Tsuda, Shunsuke; Takeda, Hiroyuki; Nagata, Takahiro; Banal, Ryan G.; Yoshikawa, Hideki; Yang, AnLi; Yamashita, Yoshiyuki; Kobayashi, Keisuke; Koide, Yasuo; Yamaguchi, Tomohiro; Kaneko, Masamitsu; Uematsu, Nao; Wang, Ke; Araki, Tsutomu; Nanishi, Yasushi

2018-03-01

The surface and bulk electronic structures of In0.7Ga0.3N epilayers are investigated by angle-resolved hard X-ray photoelectron spectroscopy (HX-PES) combined with soft X-PES. The unintentionally and Mg-doped In0.7Ga0.3N (u-In0.7Ga0.3N and In0.7Ga0.3N:Mg, respectively) epilayers are grown by radio-frequency plasma-assisted molecular beam epitaxy. Here three samples with different Mg concentrations ([Mg] = 0, 7 × 1019, and 4 × 1020 cm-3) are chosen for comparison. It is found that a large downward energy band bending exists in all samples due to the formation of a surface electron accumulation (SEA) layer. For u-In0.7Ga0.3N epilayer, band bending as large as 0.8 ± 0.05 eV occurs from bulk to surface. Judged from the valence band spectral edge and numerical analysis of energy band with a surface quantum well, the valence band maximum (VBM) with respect to Fermi energy (EF) level in the bulk is determined to be 1.22 ± 0.05 eV. In contrast, for In0.7Ga0.3N:Mg epilayers, the band bending increases and the VBM only in the bulk tends to shift toward the EF level owing to the Mg acceptor doping. Hence, the energy band is considered to exhibit a downward bending structure due to the coexistence of the n+ SEA layer and Mg-doped p layer formed in the bulk. When [Mg] changes from 7 × 1019 to 4 × 1020 cm-3, the peak split occurs in HX-PES spectra under the bulk sensitive condition. This result indicates that the energy band forms an anomalous downward bending structure with a singular point due to the generation of a thin depleted region at the n+ p interface. For In0.7Ga0.3N:Mg epilayers, the VBM in the bulk is assumed to be slightly lower than EF level within 0.1 eV.

Detoxification of Toxic Phorbol Esters from Malaysian Jatropha curcas Linn. Kernel by Trichoderma spp. and Endophytic Fungi

PubMed Central

Najjar, Azhar; Abdullah, Norhani; Saad, Wan Zuhainis; Ahmad, Syahida; Oskoueian, Ehsan; Abas, Faridah; Gherbawy, Youssuf

2014-01-01

The presence of phorbol esters (PEs) with toxic properties limits the use of Jatropha curcas kernel in the animal feed industry. Therefore, suitable methods to detoxify PEs have to be developed to render the material safe as a feed ingredient. In the present study, the biological treatment of the extracted PEs-rich fraction with non-pathogenic fungi (Trichoderma harzianum JQ350879.1, T. harzianum JQ517493.1, Paecilomyces sinensis JQ350881.1, Cladosporium cladosporioides JQ517491.1, Fusarium chlamydosporum JQ350882.1, F. chlamydosporum JQ517492.1 and F. chlamydosporum JQ350880.1) was conducted by fermentation in broth cultures. The PEs were detected by liquid chromatography-diode array detector-electrospray ionization mass spectrometry (LC-DAD-ESIMS) and quantitatively monitored by HPLC using phorbol-12-myristate 13-acetate as the standard. At day 30 of incubation, two T. harzianum spp., P. sinensis and C. cladosporioides significantly (p < 0.05) removed PEs with percentage losses of 96.9%–99.7%, while F. chlamydosporum strains showed percentage losses of 88.9%–92.2%. All fungal strains could utilize the PEs-rich fraction for growth. In the cytotoxicity assay, cell viabilities of Chang liver and NIH 3T3 fibroblast cell lines were less than 1% with the untreated PEs-rich fraction, but 84.3%–96.5% with the fungal treated PEs-rich fraction. There was no inhibition on cell viability for normal fungal growth supernatants. To conclude, Trichoderma spp., Paecilomyces sp. and Cladosporium sp. are potential microbes for the detoxification of PEs. PMID:24504029

Detoxification of toxic phorbol esters from Malaysian Jatropha curcas Linn. kernel by Trichoderma spp. and endophytic fungi.

PubMed

Najjar, Azhar; Abdullah, Norhani; Saad, Wan Zuhainis; Ahmad, Syahida; Oskoueian, Ehsan; Abas, Faridah; Gherbawy, Youssuf

2014-02-05

The presence of phorbol esters (PEs) with toxic properties limits the use of Jatropha curcas kernel in the animal feed industry. Therefore, suitable methods to detoxify PEs have to be developed to render the material safe as a feed ingredient. In the present study, the biological treatment of the extracted PEs-rich fraction with non-pathogenic fungi (Trichoderma harzianum JQ350879.1, T. harzianum JQ517493.1, Paecilomyces sinensis JQ350881.1, Cladosporium cladosporioides JQ517491.1, Fusarium chlamydosporum JQ350882.1, F. chlamydosporum JQ517492.1 and F. chlamydosporum JQ350880.1) was conducted by fermentation in broth cultures. The PEs were detected by liquid chromatography-diode array detector-electrospray ionization mass spectrometry (LC-DAD-ESIMS) and quantitatively monitored by HPLC using phorbol-12-myristate 13-acetate as the standard. At day 30 of incubation, two T. harzianum spp., P. sinensis and C. cladosporioides significantly (p < 0.05) removed PEs with percentage losses of 96.9%-99.7%, while F. chlamydosporum strains showed percentage losses of 88.9%-92.2%. All fungal strains could utilize the PEs-rich fraction for growth. In the cytotoxicity assay, cell viabilities of Chang liver and NIH 3T3 fibroblast cell lines were less than 1% with the untreated PEs-rich fraction, but 84.3%-96.5% with the fungal treated PEs-rich fraction. There was no inhibition on cell viability for normal fungal growth supernatants. To conclude, Trichoderma spp., Paecilomyces sp. and Cladosporium sp. are potential microbes for the detoxification of PEs.

Application of Koopmans' theorem for density functional theory to full valence-band photoemission spectroscopy modeling.

PubMed

Li, Tsung-Lung; Lu, Wen-Cai

2015-10-05

In this work, Koopmans' theorem for Kohn-Sham density functional theory (KS-DFT) is applied to the photoemission spectra (PES) modeling over the entire valence-band. To examine the validity of this application, a PES modeling scheme is developed to facilitate a full valence-band comparison of theoretical PES spectra with experiments. The PES model incorporates the variations of electron ionization cross-sections over atomic orbitals and a linear dispersion of spectral broadening widths. KS-DFT simulations of pristine rubrene (5,6,11,12-tetraphenyltetracene) and potassium-rubrene complex are performed, and the simulation results are used as the input to the PES models. Two conclusions are reached. First, decompositions of the theoretical total spectra show that the dissociated electron of the potassium mainly remains on the backbone and has little effect on the electronic structures of phenyl side groups. This and other electronic-structure results deduced from the spectral decompositions have been qualitatively obtained with the anionic approximation to potassium-rubrene complexes. The qualitative validity of the anionic approximation is thus verified. Second, comparison of the theoretical PES with the experiments shows that the full-scale simulations combined with the PES modeling methods greatly enhance the agreement on spectral shapes over the anionic approximation. This agreement of the theoretical PES spectra with the experiments over the full valence-band can be regarded, to some extent, as a collective validation of the application of Koopmans' theorem for KS-DFT to valence-band PES, at least, for this hydrocarbon and its alkali-adsorbed complex. Copyright © 2015 Elsevier B.V. All rights reserved.

The anatomical and imaging study of pes anserinus and its clinical application

PubMed Central

Zhong, Sheng; Wu, Bo; Wang, Miao; Wang, Xiaohong; Yan, Qi; Fan, Xingyu; Hu, Yanmei; Han, Yingying; Li, Youqiong

2018-01-01

Abstract Background: The pes anserinus was an important graft choice for anterior cruciate ligament (ACL) reconstruction. The infrapatellar branch of the saphenous nerve (IPBSN) might be damaged in this surgery. This study aimed to provide anatomic and ultrasonic measurement data of pes anserinus and superficial nerves. Methods: Eighty lower limb specimens of forty adult cadavers were dissected. The length, width, thickness, and the position of the tibial attachment of pes anserinus tendons were anthropometric measured, as well as the distance between the infrapatellar branch of the saphenous nerve and the pes anserinus. Sixty healthy adult participants were enrolled for ultrasonic research. The length, width, thickness of pes anserinus was also measured and the saphenous nerve was also assessed. Results: Anatomic results showed that there were 3 types of pes anserinus, the infrapatellar branch of the saphenous nerve (IPBSN) was almost paralleled to the upper edge of the pes anserinus tendon, and the average of distance between them was about 0.95 cm. The length of semitendinosus and gracilis tendons were 146.49 ± 12.83 mm and 124.62 ± 8.86 mm, the width of sartorius tendon was 25.58 ± 4.65 mm, wider than other tendons. The classification of pes anserinus tendons and the saphenous nerves could be identified in ultrasonic image. The length of semitendinosus and gracilis tendons were 151.35 ± 9.65 mm and 120.86 ± 8.99 mm, the width of sartorius tendon was 22.84 ± 3.83 mm. And there was no significance difference between anatomic and ultrasonic measurement (P > .05). Conclusion: The morphology of pes anserinus and its peripheral structures could be identified and measured precisely by ultrasound device, a presurgical ultrasonic examination was recommended. The arrangement of pes anserinus tendons was classified into 3 types according to our results. The incision should be performed medial to tibial eminence 1.5 cm and under the tibial tubercle level 2 to 3 cm, an oblique incision formed an angle of 50° with tibial transection was recommend, which was parallel to the direction of pes anserinus tendon. PMID:29642176

The bi-directional associations between psychotic experiences and DSM-IV mental disorders

PubMed Central

McGrath, John J.; Saha, Sukanta; Al-Hamzawi, Ali; Andrade, Laura; Benjet, Corina; Bromet, Evelyn J.; Browne, Mark Oakley; Caldas de Almeida, Jose M.; Chiu, Wai Tat; Demyttenaere, Koen; Fayyad, John; Florescu, Silvia; de Girolamo, Giovanni; Gureje, Oye; Haro, Josep Maria; Have, Margreet ten; Hu, Chiyi; Kovess-Masfety, Viviane; Lim, Carmen C. W.; Navarro-Mateu, Fernando; Sampson, Nancy; Posada-Villa, José; Kendler, Kenneth; Kessler, Ronald C.

2016-01-01

Objective While it is now recognized that psychotic experiences (PEs) are associated with an increased risk of later mental disorders, we lack a detailed understanding of the reciprocal time-lagged relationships between first onsets of PEs and mental disorders. Methods The WHO World Mental Health (WMH) surveys assessed lifetime prevalence and age-of-onset of PEs and 21 common DSM-IV mental disorders among 31,261 adult respondents from 18 countries. Results Temporally primary PEs were significantly associated with subsequent first onset of 8 of the 21 mental disorders (major depressive disorder, bipolar disorder, generalized anxiety disorder, social phobia, post-traumatic stress disorder, adult separation anxiety disorder, bulimia nervosa, alcohol abuse), with ORs (95%CI) ranging from 1.3 (1.2–1.5; major depressive disorder) to 2.0 (1.5–2.6; bipolar disorder). In contrast, 18 of 21 primary mental disorders were significantly associated with subsequent first onset of PEs, with ORs (95% CI) ranging from 1.5 (1.0–2.1; childhood separation anxiety disorder) to 2.8 (1.0–7.8; anorexia nervosa). Conclusions While temporally primary PEs are associated with an elevated risk of several subsequent mental disorders, we found that most mental disorder are associated with an elevated risk of subsequent PEs. Further investigation of the underlying factors accounting for these time-order relationships might shed light on the etiology of PEs. PMID:26988628

Occular and dermal toxicity of Jatropha curcas phorbol esters.

PubMed

Devappa, Rakshit K; Roach, Joy S; Makkar, Harinder P S; Becker, Klaus

2013-08-01

Jatropha curcas seeds are a promising feedstock for biodiesel production. However, Jatropha seed oil and other plant parts are toxic due to the presence of phorbol esters (PEs). The ever-increasing cultivation of toxic genotype of J. curcas runs the risk of increased human exposure to Jatropha products. In the present study, effects of J. curcas oil (from both toxic and nontoxic genotypes), purified PEs-rich extract and purified PEs (factors C1, C2, C(3mixture), (C4+C5)) on reconstituted human epithelium (RHE) and human corneal epithelium (HCE) were evaluated in vitro. The PEs were purified from toxic Jatropha oil. In both RHE and HCE, the topical application of PEs containing samples produced severe cellular alterations such as marked oedema, presence of less viable cell layers, necrosis and/or partial tissue disintegration in epithelium and increased inflammatory response (interleukin-1α and prostaglandin E2). When compared to toxic oil, histological alterations and inflammatory response were less evident (P<0.05) in nontoxic oil indicating the severity of toxicity was due to PEs. Conclusively, topical applications of Jatropha PEs are toxic towards RHE and HCE models, which represents dermal and occular toxicity respectively. Data obtained from this study would aid in the development of safety procedures for Jatropha biodiesel industries. It is advised to use protective gloves and glasses when handling PEs containing Jatropha products. Copyright © 2013 Elsevier Inc. All rights reserved.

Psychotic experiences and religiosity: data from the WHO World Mental Health Surveys.

PubMed

Kovess-Masfety, V; Saha, S; Lim, C C W; Aguilar-Gaxiola, S; Al-Hamzawi, A; Alonso, J; Borges, G; de Girolamo, G; de Jonge, P; Demyttenaere, K; Florescu, S; Haro, J M; Hu, C; Karam, E G; Kawakami, N; Lee, S; Lepine, J P; Navarro-Mateu, F; Stagnaro, J C; Ten Have, M; Viana, M C; Kessler, R C; McGrath, J J

2018-04-01

Religiosity is often associated with better health outcomes. The aim of the study was to examine associations between psychotic experiences (PEs) and religiosity in a large, cross-national sample. A total of 25 542 adult respondents across 18 countries from the WHO World Mental Health Surveys were assessed for PEs, religious affiliation and indices of religiosity, DSM-IV mental disorders and general medical conditions. Logistic regression models were used to estimate the association between PEs and religiosity with various adjustments. Of 25 542 included respondents, 85.6% (SE = 0.3) (n = 21 860) respondents reported having a religious affiliation. Overall, there was no association between religious affiliation status and PEs. Within the subgroup having a religious affiliation, four of five indices of religiosity were significantly associated with increased odds of PEs (odds ratios ranged from 1.3 to 1.9). The findings persisted after adjustments for mental disorders and/or general medical conditions, as well as religious denomination type. There was a significant association between increased religiosity and reporting more types of PEs. Among individuals with religious affiliations, those who reported more religiosity on four of five indices had increased odds of PEs. Focussed and more qualitative research will be required to unravel the interrelationship between religiosity and PEs. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Enhanced chondrogenesis of human bone marrow mesenchymal Stem Cell (BMSC) on nanofiber-based polyethersulfone (PES) scaffold.

PubMed

Mahboudi, Hossein; Kazemi, Bahram; Soleimani, Masoud; Hanaee-Ahvaz, Hana; Ghanbarian, Hossein; Bandehpour, Mojgan; Enderami, Seyed Ehsan; Kehtari, Mousa; Barati, Ghasem

2018-02-15

Mesenchymal stem cells (MSC) from bone marrow hold great potential as a cell source for cartilage repair. The objective of our study was differentiation of MSC toward chondrocyte by using Nanofiber-based polyethersulfone (PES) scaffold and also enhanced chondrogenic differentiation of BMSC in vitro. MSCs were harvested from bone marrow of human and PES scaffold was fabricated via Electrospinning. The isolated cells were cultured on the PES scaffold and scaffold free method. After 21days, Real-time PCR was performed to evaluate the cartilage-specific genes in the mRNA levels. Also, in order to confirm our results, we have done immunocytochemistry and SEM imaging. Flowcytometry confirmed the nature of the isolated adherent cells. Immunocytochemistry and SEM imaging confirmed the differentiation of MSC toward chondrocyte. Also, real time PCR showed a significant increased gene expression of collagen type II and aggrecan on the PES scaffold method when compared to the mRNA levels measured in scaffold free method. Down regulation of Collagen type I was observed in PES scaffold compared to scaffold free at day 21. Also, both methods showed a similar pattern of expression of SOX9. Our results showed that PES scaffold maintains BMSC proliferation and differentiation, and can significantly enhance chondrogenic differentiation of BMSC. PES scaffold seeded BMSC showed the highest capacity for differentiation into chondrocyte-like cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Drama in Dynamics: Boom, Splash, and Speed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Netzloff, Heather Marie

2004-12-19

The full nature of chemistry and physics cannot be captured by static calculations alone. Dynamics calculations allow the simulation of time-dependent phenomena. This facilitates both comparisons with experimental data and the prediction and interpretation of details not easily obtainable from experiments. Simulations thus provide a direct link between theory and experiment, between microscopic details of a system and macroscopic observed properties. Many types of dynamics calculations exist. The most important distinction between the methods and the decision of which method to use can be described in terms of the size and type of molecule/reaction under consideration and the type andmore » level of accuracy required in the final properties of interest. These considerations must be balanced with available computational codes and resources as simulations to mimic ''real-life'' may require many time steps. As indicated in the title, the theme of this thesis is dynamics. The goal is to utilize the best type of dynamics for the system under study while trying to perform dynamics in the most accurate way possible. As a quantum chemist, this involves some level of first principles calculations by default. Very accurate calculations of small molecules and molecular systems are now possible with relatively high-level ab initio quantum chemistry. For example, a quantum chemical potential energy surface (PES) can be developed ''on-the-fly'' with dynamic reaction path (DRP) methods. In this way a classical trajectory is developed without prior knowledge of the PES. In order to treat solvation processes and the condensed phase, large numbers of molecules are required, especially in predicting bulk behavior. The Effective Fragment Potential (EFP) method for solvation decreases the cost of a fully quantum mechanical calculation by dividing a chemical system into an ab initio region that contains the solute and an ''effective fragment'' region that contains the remaining solvent molecules. But, despite the reduced cost relative to fully QM calculations, the EFP method, due to its complex, QM-based potential, does require more computation time than simple interaction potentials, especially when the method is used for large scale molecular dynamics simulations. Thus, the EFP method was parallelized to facilitate these calculations within the quantum chemistry program GAMESS. The EFP method provides relative energies and structures that are in excellent agreement with the analogous fully quantum results for small water clusters. The ability of the method to predict bulk water properties with a comparable accuracy is assessed by performing EFP molecular dynamics simulations. Molecular dynamics simulations can provide properties that are directly comparable with experimental results, for example radial distribution functions. The molecular PES is a fundamental starting point for chemical reaction dynamics. Many methods can be used to obtain a PES; for example, assuming a global functional form for the PES or, as mentioned above, performing ''on-the-fly'' dynamics with Al or semi-empirical calculations at every molecular configuration. But as the size of the system grows, using electronic structure theory to build a PES and, therefore, study reaction dynamics becomes virtually impossible. The program Grow builds a PES as an interpolation of Al data; the goal is to attempt to produce an accurate PES with the smallest number of Al calculations. The Grow-GAMESS interface was developed to obtain the Al data from GAMESS. Classical or quantum dynamics can be performed on the resulting surface. The interface includes the novel capability to build multi-reference PESs; these types of calculations are applicable to problems ranging from atmospheric chemistry to photochemical reaction mechanisms in organic and inorganic chemistry to fundamental biological phenomena such as photosynthesis.« less

Expansion Hamiltonian model for a diatomic molecule adsorbed on a surface: Vibrational states of the CO/Cu(100) system including surface vibrations

NASA Astrophysics Data System (ADS)

Meng, Qingyong; Meyer, Hans-Dieter

2015-10-01

Molecular-surface studies are often done by assuming a corrugated, static (i.e., rigid) surface. To be able to investigate the effects that vibrations of surface atoms may have on spectra and cross sections, an expansion Hamiltonian model is proposed on the basis of the recently reported [R. Marquardt et al., J. Chem. Phys. 132, 074108 (2010)] SAP potential energy surface (PES), which was built for the CO/Cu(100) system with a rigid surface. In contrast to other molecule-surface coupling models, such as the modified surface oscillator model, the coupling between the adsorbed molecule and the surface atoms is already included in the present expansion SAP-PES model, in which a Taylor expansion around the equilibrium positions of the surface atoms is performed. To test the quality of the Taylor expansion, a direct model, that is avoiding the expansion, is also studied. The latter, however, requests that there is only one movable surface atom included. On the basis of the present expansion and direct models, the effects of a moving top copper atom (the one to which CO is bound) on the energy levels of a bound CO/Cu(100) system are studied. For this purpose, the multiconfiguration time-dependent Hartree calculations are carried out to obtain the vibrational fundamentals and overtones of the CO/Cu(100) system including a movable top copper atom. In order to interpret the results, a simple model consisting of two coupled harmonic oscillators is introduced. From these calculations, the vibrational levels of the CO/Cu(100) system as function of the frequency of the top copper atom are discussed.

Expansion Hamiltonian model for a diatomic molecule adsorbed on a surface: Vibrational states of the CO/Cu(100) system including surface vibrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Qingyong, E-mail: mengqingyong@dicp.ac.cn; Meyer, Hans-Dieter, E-mail: hans-dieter.meyer@pci.uni-heidelberg.de

2015-10-28

Molecular-surface studies are often done by assuming a corrugated, static (i.e., rigid) surface. To be able to investigate the effects that vibrations of surface atoms may have on spectra and cross sections, an expansion Hamiltonian model is proposed on the basis of the recently reported [R. Marquardt et al., J. Chem. Phys. 132, 074108 (2010)] SAP potential energy surface (PES), which was built for the CO/Cu(100) system with a rigid surface. In contrast to other molecule-surface coupling models, such as the modified surface oscillator model, the coupling between the adsorbed molecule and the surface atoms is already included in themore » present expansion SAP-PES model, in which a Taylor expansion around the equilibrium positions of the surface atoms is performed. To test the quality of the Taylor expansion, a direct model, that is avoiding the expansion, is also studied. The latter, however, requests that there is only one movable surface atom included. On the basis of the present expansion and direct models, the effects of a moving top copper atom (the one to which CO is bound) on the energy levels of a bound CO/Cu(100) system are studied. For this purpose, the multiconfiguration time-dependent Hartree calculations are carried out to obtain the vibrational fundamentals and overtones of the CO/Cu(100) system including a movable top copper atom. In order to interpret the results, a simple model consisting of two coupled harmonic oscillators is introduced. From these calculations, the vibrational levels of the CO/Cu(100) system as function of the frequency of the top copper atom are discussed.« less

Psychiatric Emergency Services for the U.S. Elderly: 2008 and Beyond

PubMed Central

Walsh, Patrick G.; Currier, Glenn; Shah, Manish N.; Lyness, Jeffrey M.; Friedman, Bruce

2008-01-01

In 2011 the oldest baby boomers will turn age 65. Although healthcare researchers have started to examine the future preparedness of the healthcare system for the elderly, psychiatric emergency services (PES) have been widely overlooked. Research is needed to address PES need and demand by older patients, assess the consequences of this need/demand, and establish recommendations to guide PES planning and practice. The authors examined journal articles, review papers, textbooks, and electronic databases related to these topics. We outline the current PES environment in terms of facilities, characteristics, and visits, and discuss current geriatric patient PES use. Factors expected to impact future use are examined, including sociodemographic characteristics, psychiatric illness prevalence, cohort effects, medical comorbidity, mental healthcare resources and utilization, and stigma. Consequences of these on future psychiatric care and well-being of the elderly are then explored, specifically, greater acute services need, more suicide, strained delivery systems, increased hospitalization, and greater costs. The following are proposed to address likely future PES shortcomings: enhance service delivery, increase training, standardize and improve PES, prioritize finances, and promote research. The degree to which the geriatric mental healthcare “crisis” develops will be inversely related to the current system's response to predictable future needs. PMID:18757766

Psychotic Experiences, Working Memory, and the Developing Brain: A Multimodal Neuroimaging Study

PubMed Central

Fonville, Leon; Cohen Kadosh, Kathrin; Drakesmith, Mark; Dutt, Anirban; Zammit, Stanley; Mollon, Josephine; Reichenberg, Abraham; Lewis, Glyn; Jones, Derek K.; David, Anthony S.

2015-01-01

Psychotic experiences (PEs) occur in the general population, especially in children and adolescents, and are associated with poor psychosocial outcomes, impaired cognition, and increased risk of transition to psychosis. It is unknown how the presence and persistence of PEs during early adulthood affects cognition and brain function. The current study assessed working memory as well as brain function and structure in 149 individuals, with and without PEs, drawn from a population cohort. Observer-rated PEs were classified as persistent or transient on the basis of longitudinal assessments. Working memory was assessed using the n-back task during fMRI. Dynamic causal modeling (DCM) was used to characterize frontoparietal network configuration and voxel-based morphometry was utilized to examine gray matter. Those with persistent, but not transient, PEs performed worse on the n-back task, compared with controls, yet showed no significant differences in regional brain activation or brain structure. DCM analyses revealed greater emphasis on frontal connectivity within a frontoparietal network in those with PEs compared with controls. We propose that these findings portray an altered configuration of working memory function in the brain, potentially indicative of an adaptive response to atypical development associated with the manifestation of PEs. PMID:26286920

Quasiclassical trajectory study of the Cl+CH4 reaction dynamics on a quadratic configuration interaction with single and double excitation interpolated potential energy surface.

PubMed

Castillo, J F; Aoiz, F J; Bañares, L

2006-09-28

An ab initio interpolated potential energy surface (PES) for the Cl+CH(4) reactive system has been constructed using the interpolation method of Collins and co-workers [J. Chem. Phys. 102, 5647 (1995); 108, 8302 (1998); 111, 816 (1999); Theor. Chem. Acc. 108, 313 (2002)]. The ab initio calculations have been performed using quadratic configuration interaction with single and double excitation theory to build the PES. A simple scaling all correlation technique has been used to obtain a PES which yields a barrier height and reaction energy in good agreement with high level ab initio calculations and experimental measurements. Using these interpolated PESs, a detailed quasiclassical trajectory study of integral and differential cross sections, product rovibrational populations, and internal energy distributions has been carried out for the Cl+CH(4) and Cl+CD(4) reactions, and the theoretical results have been compared with the available experimental data. It has been shown that the calculated total reaction cross sections versus collision energy for the Cl+CH(4) and Cl+CD(4) reactions is very sensitive to the barrier height. Besides, due to the zero-point energy (ZPE) leakage of the CH(4) molecule to the reaction coordinate in the quasiclassical trajectory (QCT) calculations, the reaction threshold falls below the barrier height of the PES. The ZPE leakage leads to CH(3) and HCl coproducts with internal energy below its corresponding ZPEs. We have shown that a Gaussian binning (GB) analysis of the trajectories yields excitation functions in somehow better agreement with the experimental determinations. The HCl(v'=0) and DCl(v'=0) rotational distributions are as well very sensitive to the ZPE problem. The GB correction narrows and shifts the rotational distributions to lower values of the rotational quantum numbers. However, the present QCT rotational distributions are still hotter than the experimental distributions. In both reactions the angular distributions shift from backward peaked to sideways peaked as collision energy increases, as seen in the experiments and other theoretical calculations.

Quasiclassical trajectory study of the Cl +CH4 reaction dynamics on a quadratic configuration interaction with single and double excitation interpolated potential energy surface

NASA Astrophysics Data System (ADS)

Castillo, J. F.; Aoiz, F. J.; Bañares, L.

2006-09-01

An ab initio interpolated potential energy surface (PES) for the Cl +CH4 reactive system has been constructed using the interpolation method of Collins and co-workers [J. Chem. Phys. 102, 5647 (1995); 108, 8302 (1998); 111, 816 (1999); Theor. Chem. Acc. 108, 313 (2002)]. The ab initio calculations have been performed using quadratic configuration interaction with single and double excitation theory to build the PES. A simple scaling all correlation technique has been used to obtain a PES which yields a barrier height and reaction energy in good agreement with high level ab initio calculations and experimental measurements. Using these interpolated PESs, a detailed quasiclassical trajectory study of integral and differential cross sections, product rovibrational populations, and internal energy distributions has been carried out for the Cl +CH4 and Cl +CD4 reactions, and the theoretical results have been compared with the available experimental data. It has been shown that the calculated total reaction cross sections versus collision energy for the Cl +CH4 and Cl +CD4 reactions is very sensitive to the barrier height. Besides, due to the zero-point energy (ZPE) leakage of the CH4 molecule to the reaction coordinate in the quasiclassical trajectory (QCT) calculations, the reaction threshold falls below the barrier height of the PES. The ZPE leakage leads to CH3 and HCl coproducts with internal energy below its corresponding ZPEs. We have shown that a Gaussian binning (GB) analysis of the trajectories yields excitation functions in somehow better agreement with the experimental determinations. The HCl(v'=0) and DCl(v'=0) rotational distributions are as well very sensitive to the ZPE problem. The GB correction narrows and shifts the rotational distributions to lower values of the rotational quantum numbers. However, the present QCT rotational distributions are still hotter than the experimental distributions. In both reactions the angular distributions shift from backward peaked to sideways peaked as collision energy increases, as seen in the experiments and other theoretical calculations.

Association between childhood psychiatric disorders and psychotic experiences in adolescence: A population-based longitudinal study.

PubMed

Siebald, Caroline; Khandaker, Golam M; Zammit, Stanley; Lewis, Glyn; Jones, Peter B

2016-08-01

Adolescent psychotic experiences (PEs) are common, and are associated with both psychotic and non-psychotic illnesses. In order to examine psychopathological and cognitive antecedents of adolescent PEs, we have conducted a longitudinal study of common childhood psychiatric disorders and subsequent adolescent PEs in the population-based prospective ALSPAC birth cohort. Depression, anxiety, attention deficit hyperactivity disorder, oppositional defiant or conduct disorder, and pervasive developmental disorder were diagnosed according to DSM-IV criteria in 8253 participants at age 8years. IQ was assessed by WISC-III also at 8years. PEs, depressive and anxiety symptoms were assessed at 13years. Logistic regression calculated odds ratio (OR) for PEs at 13years associated with psychiatric disorders at 8years. Linear regression calculated mean difference in IQ between groups with and without psychiatric disorder. Mediating effects of IQ, mood and anxiety symptoms on the psychiatric disorder-PEs relationship were examined. In total, 599 children were assessed to have a DSM-IV psychiatric disorder at 8years (7.2%). These children compared with those without any psychiatric disorder performed worse on all measures of IQ; adjusted mean difference in total IQ -6.17 (95% CI, -7.86, -4.48). Childhood psychiatric disorders were associated with PEs subsequently in adolescence; adjusted OR 1.96 (95% CI, 1.47-2.68). The association between psychiatric disorder and subsequent PEs was partly mediated by, independently, IQ deficit at 8years and depressive and anxiety symptoms at 13years. The findings indicate that adolescent PEs are associated with general cognitive ability and past and present psychopathological factors. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Foot posture is associated with kinematics of the foot during gait: A comparison of normal, planus and cavus feet.

PubMed

Buldt, Andrew K; Levinger, Pazit; Murley, George S; Menz, Hylton B; Nester, Christopher J; Landorf, Karl B

2015-06-01

Variations in foot posture are associated with the development of some lower limb injuries. However, the mechanisms underlying this relationship are unclear. The objective of this study was to compare foot kinematics between normal, pes cavus and pes planus foot posture groups using a multi-segment foot model. Ninety-seven healthy adults, aged 18-47 were classified as either normal (n=37), pes cavus (n=30) or pes planus (n=30) based on normative data for the Foot Posture Index, Arch Index and normalised navicular height. A five segment foot model was used to measure tri-planar motion of the rearfoot, midfoot, medial forefoot, lateral forefoot and hallux during barefoot walking at a self-selected speed. Angle at heel contact, peak angle, time to peak angle and range of motion was measured for each segment. One way ANOVAs with post-hoc analyses of mean differences were used to compare foot posture groups. The pes cavus group demonstrated a distinctive pattern of motion compared to the normal and pes planus foot posture groups. Effect sizes of significant mean differences were large and comparable to similar studies. Three key differences in overall foot function were observed between the groups: (i) altered frontal and transverse plane angles of the rearfoot in the pes cavus foot; (ii) Less midfoot motion in the pes cavus foot during initial contact and midstance; and (iii) reduced midfoot frontal plane ROM in the pes planus foot during pre-swing. These findings indicate that foot posture does influence motion of the foot. Copyright © 2015 Elsevier B.V. All rights reserved.

Impact of payments for environmental services and protected areas on local livelihoods and forest conservation in northern Cambodia.

PubMed

Clements, Tom; Milner-Gulland, E J

2015-02-01

The potential impacts of payments for environmental services (PES) and protected areas (PAs) on environmental outcomes and local livelihoods in developing countries are contentious and have been widely debated. The available evidence is sparse, with few rigorous evaluations of the environmental and social impacts of PAs and particularly of PES. We measured the impacts on forests and human well-being of three different PES programs instituted within two PAs in northern Cambodia, using a panel of intervention villages and matched controls. Both PES and PAs delivered additional environmental outcomes relative to the counterfactual: reducing deforestation rates significantly relative to controls. PAs increased security of access to land and forest resources for local households, benefiting forest resource users but restricting households' ability to expand and diversify their agriculture. The impacts of PES on household well-being were related to the magnitude of the payments provided. The two higher paying market-linked PES programs had significant positive impacts, whereas a lower paying program that targeted biodiversity protection had no detectable effect on livelihoods, despite its positive environmental outcomes. Households that signed up for the higher paying PES programs, however, typically needed more capital assets; hence, they were less poor and more food secure than other villagers. Therefore, whereas the impacts of PAs on household well-being were limited overall and varied between livelihood strategies, the PES programs had significant positive impacts on livelihoods for those that could afford to participate. Our results are consistent with theories that PES, when designed appropriately, can be a powerful new tool for delivering conservation goals whilst benefiting local people. © 2014 The Authors. Conservation Biology published by Wiley Periodicals, Inc. on behalf of Society for Conservation Biology.

Effects of a polyelectrolyte additive on the selective dialysis membrane permeability for low-molecular-weight proteins.

PubMed

Krieter, Detlef H; Morgenroth, Andreas; Barasinski, Artur; Lemke, Horst-Dieter; Schuster, Oliver; von Harten, Bodo; Wanner, Christoph

2007-02-01

Improving the sieving characteristics of dialysis membranes enhances the clearance of low-molecular-weight (LMW) proteins and may have an impact on outcome in patients receiving haemodialysis. To approach this goal, a novel polyelectrolyte additive process was applied to a polyethersulphone (PES) membrane. Polyelectrolyte-modified PES was characterized in vitro by measuring complement activation and sieving coefficients of cytochrome c and serum albumin. In a prospective, randomized, cross-over study, instantaneous plasma water clearances and reduction rates of LMW proteins [beta(2)-microglobulin (b2m), cystatin c, myoglobin, retinol binding protein] were determined in eight patients receiving dialysis treatment with PES in comparison with polysulphone (PSU). Biocompatibility was assessed by determination of transient leucopenia, plasma levels of complement C5a, thrombin-antithrombin III (TAT), myeloperoxidase (MPO) and elastase (ELT). PES showed a steeper sieving profile and lower complement activation in vitro compared with PSU. Instantaneous clearance (69 +/- 8 vs. 58 +/- 3 ml/min; P < 0.001) and reduction rate (72.3 +/- 1 5% vs 66.2 +/- 6.1%; P < 0.001) of b2m were significantly higher with PES as compared with PSU. With higher molecular weight of proteins, differences in the solute removal between PES and PSU further increased, whereas albumin loss remained low (PES, 0.53 +/- 0.17 vs PSU, <0.22 g/dialysis). MPO, ELT and TAT did not differ between the two membranes. In contrast, leucopenia was less pronounced and C5a generation was significantly lower during dialysis with PES. Polyelectrolyte modification of PES results in a higher LMW protein removal and in optimized biocompatibility. Whether these findings translate into better outcome of patients receiving haemodialysis requires further studies.

A population-based study of atopic disorders and inflammatory markers in childhood before psychotic experiences in adolescence☆

PubMed Central

Khandaker, Golam M.; Zammit, Stanley; Lewis, Glyn; Jones, Peter B.

2014-01-01

Objective Schizophrenia is associated with atopy and increased inflammatory markers. We report a population-based longitudinal study of the associations between childhood atopic disorders, subsequent serum inflammatory markers, interleukin 6 (IL-6) and C-reactive protein (CRP), and the risk of psychotic experiences (PEs). Method PEs were assessed at age 13 years (n = 6785). Presence of clinician-diagnosed atopic disorders (asthma and eczema) was determined from parent-completed questionnaires at age 10 years (n = 7814). Serum IL-6 and CRP were measured at age 9 years (n = 5076). Logistic regression examined the association between (1) atopy and PEs, (2) inflammatory markers and PEs, and (3) mediating effects of inflammatory markers on the atopy–PEs association. Linear regression examined the association between atopy and inflammatory markers. Age, gender, social class, ethnicity and body mass index were included as potential confounders. Results At age 10 years, about 14% of the sample was reported to have asthma, 12% eczema, and 7% both asthma and eczema. Compared with children with no atopy, risk of PEs at age 13 years was increased for all of these groups; adjusted odds ratios (95% CI) were, respectively, 1.39 (1.10–1.77), 1.33 (1.04–1.69), and 1.44 (1.06–1.94). Atopy was associated with increased serum IL-6 and CRP; however, this did not mediate association between atopy and PEs. Inflammatory markers were not associated with later PEs. Conclusion Childhood atopic disorders increase the risk of psychotic experiences in adolescence. Follow-up of these individuals will be useful to determine the effect of atopy and inflammation on different trajectories of early-life PEs. PMID:24268471

A population-based study of atopic disorders and inflammatory markers in childhood before psychotic experiences in adolescence.

PubMed

Khandaker, Golam M; Zammit, Stanley; Lewis, Glyn; Jones, Peter B

2014-01-01

Schizophrenia is associated with atopy and increased inflammatory markers. We report a population-based longitudinal study of the associations between childhood atopic disorders, subsequent serum inflammatory markers, interleukin 6 (IL-6) and C-reactive protein (CRP), and the risk of psychotic experiences (PEs). PEs were assessed at age 13 years (n=6785). Presence of clinician-diagnosed atopic disorders (asthma and eczema) was determined from parent-completed questionnaires at age 10 years (n=7814). Serum IL-6 and CRP were measured at age 9 years (n=5076). Logistic regression examined the association between (1) atopy and PEs, (2) inflammatory markers and PEs, and (3) mediating effects of inflammatory markers on the atopy-PEs association. Linear regression examined the association between atopy and inflammatory markers. Age, gender, social class, ethnicity and body mass index were included as potential confounders. At age 10 years, about 14% of the sample was reported to have asthma, 12% eczema, and 7% both asthma and eczema. Compared with children with no atopy, risk of PEs at age 13 years was increased for all of these groups; adjusted odds ratios (95% CI) were, respectively, 1.39 (1.10-1.77), 1.33 (1.04-1.69), and 1.44 (1.06-1.94). Atopy was associated with increased serum IL-6 and CRP; however, this did not mediate association between atopy and PEs. Inflammatory markers were not associated with later PEs. Childhood atopic disorders increase the risk of psychotic experiences in adolescence. Follow-up of these individuals will be useful to determine the effect of atopy and inflammation on different trajectories of early-life PEs. © 2013. Published by Elsevier B.V. All rights reserved.

Viscous Flow Structures Downstream of a Model Tracheoesophageal Prosthesis

NASA Astrophysics Data System (ADS)

Hemsing, Frank; Erath, Byron

2013-11-01

In tracheoesophageal speech (TES), the glottis is replaced by the tissue of the pharyngeoesophageal segment (PES) as the vibrating element of speech production. During TES air is forced from the lungs into the esophagus via a prosthetic tube that connects the trachea with the esophagus. Air moving up the esophagus incites self-sustained oscillations of the surgically created PES, generating sound analogous to voiced speech. Despite the ubiquity with which TES is employed as a method for restoring speech to laryngectomees, the effect of viscous flow structures on voice production in TES is not well understood. Of particular interest is the flow exiting the prosthetic connection between the trachea and esophagus, because of its influence on the total pressure loss (i.e. effort required to produce speech), and the fluid-structure energy exchange that drives the PES. Understanding this flow behavior can inform prosthesis design to enhance beneficial flow structures and mitigate the need for adjustment of prosthesis placement. This study employs a physical model of the tracheoesophageal geometry to investigate the flow structures that arise in TES. The geometry of this region is modeled at three times physiological scale using water as the working fluid to obtain nondimensional numbers matching flow in TES. Modulation of the flow is achieved with a computer controlled gate valve at a scaled frequency of 0.22 Hz to mimic the oscillations of the PES. Particle image velocimetry is used to resolve flow characteristics at the tracheoesophageal prosthesis. Data are acquired for three cases of prosthesis insertion angle.

Farmers value on-farm ecosystem services as important, but what are the impediments to participation in PES schemes?

PubMed

Page, Girija; Bellotti, Bill

2015-05-15

Optimal participation in market-based instruments such as PES (payment for ecosystem services) schemes is a necessary precondition for achieving large scale cost-effective conservation goals from agricultural landscapes. However farmers' willingness to participate in voluntary conservation programmes is influenced by psychological, financial and social factors and these need to be assessed on a case-by-case basis. In this research farmers' values towards on-farm ecosystem services, motivations and perceived impediments to participation in conservation programmes are identified in two local land services regions in Australia using surveys. Results indicated that irrespective of demographics such as age, gender, years farmed, area owned and annual gross farm income, farmers valued ecosystem services important for future sustainability. Non-financial motivations had significant associations with farmer's perceptions regarding attitudes and values towards the environment and participation in conservation-related programmes. Farmer factors such as lack of awareness and unavailability of adequate information were correlated with non-participation in conservation-based programmes. In the current political context, government uncertainty regarding schemes especially around carbon sequestration and reduction was the most frequently cited impediment that could deter participation. Future research that explores willingness of farmers towards participation in various types of PES programmes developed around carbon reduction, water quality provision and biodiversity conservation, and, duration of the contract and payment levels that are attractive to the farmers will provide insights for developing farmer-friendly PES schemes in the region. Copyright © 2015 Elsevier B.V. All rights reserved.

SPEEK/PVDF/PES Composite as Alternative Proton Exchange Membrane for Vanadium Redox Flow Batteries

NASA Astrophysics Data System (ADS)

Fu, Zhimin; Liu, Jinying; Liu, Qifeng

2016-01-01

A membrane consisting of a blend of sulfonated poly(ether ether ketone) (SPEEK), poly(vinylidene fluoride) (PVDF), and poly(ether sulfone) (PES) has been fabricated and used as an ion exchange membrane for application in vanadium redox flow batteries (VRBs). The vanadium ion permeability of the SPEEK/PVDF/PES membrane was one order of magnitude lower than that of Nafion 117 membrane. The low-cost composite membrane exhibited better performance than Nafion 117 membrane at the same operating condition. A VRB single cell with SPEEK/PVDF/PES membrane showed significantly lower capacity loss, higher coulombic efficiency (>95%), and higher energy efficiency (>82%) compared with Nafion 117 membrane. In the self-discharge test, the duration of the cell with the SPEEK/PVDF/PES membrane was nearly two times longer than that with Nafion 117 membrane. Considering these good properties and its low cost, SPEEK/PVDF/PES membrane is expected to have excellent commercial prospects as an ion exchange membrane for VRB systems.

The small molecule 2-phenylethynesulfonamide induces covalent modification of p53

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jamil, Sarwat; Hojabrpour, Payman; Duronio, Vincent

p53 is a tumor suppressor protein which is either lost or inactivated in a large majority of tumors. The small molecule 2-phenylethynesulfonamide (PES) was originally identified as the inhibitor of p53 effects on the mitochondrial death pathway. In this report we demonstrate that p53 protein from PES-treated cells was detected in reduced mobility bands between molecular weights 95–220 kDa. Resolution of p53 aggregates on urea gel was unable to reduce the high molecular weight p53 aggregates, which were shown to be primarily located in the nucleus. Therefore, our data suggest that PES exerts its effects through covalent cross-linking and nuclear retentionmore » of p53. - Highlights: • p53 protein is in high molecular weight complexes in the nucleus of PES-treated cells. • PES is a drug that inhibits pro-apoptotic p53 action at the mitochondria. • We propose that PES action involves cross-linking and nuclear retention of p53.« less

A new ab initio potential energy surface of LiClH (1A') system and quantum dynamics calculation for Li + HCl (v = 0, j = 0-2) → LiCl + H reaction

NASA Astrophysics Data System (ADS)

Tan, Rui Shan; Zhai, Huan Chen; Yan, Wei; Gao, Feng; Lin, Shi Ying

2017-04-01

A new ab initio potential energy surface (PES) for the ground state of Li + HCl reactive system has been constructed by three-dimensional cubic spline interpolation of 36 654 ab initio points computed at the MRCI+Q/aug-cc-pV5Z level of theory. The title reaction is found to be exothermic by 5.63 kcal/mol (9 kcal/mol with zero point energy corrections), which is very close to the experimental data. The barrier height, which is 2.99 kcal/mol (0.93 kcal/mol for the vibrationally adiabatic barrier height), and the depth of van der Waals minimum located near the entrance channel are also in excellent agreement with the experimental findings. This study also identified two more van der Waals minima. The integral cross sections, rate constants, and their dependence on initial rotational states are calculated using an exact quantum wave packet method on the new PES. They are also in excellent agreement with the experimental measurements.

Comparative evaluation of Chitosan, Cellulose Acetate, and Polyethersulfone Nanofiber Scaffolds for Neural Differentiation

PubMed Central

Du, Jian; Tan, Elaine; Kim, Hyo Jun; Zhang, Allen; Bhattacharya, Rahul; Yarema, Kevin J

2013-01-01

Based on accumulating evidence that the 3D topography and the chemical features of a growth surface influence neuronal differentiation, we combined these two features by evaluating the cytotoxicity, proliferation, and differentiation of the rat PC12 line and human neural stem cells (hNSCs) on chitosan (CS), cellulose acetate (CA), and polyethersulfone (PES)-derived electrospun nanofibers that had similar diameters, centered in the 200 to 500 nm range. None of the nanofibrous materials were cytotoxic compared to 2D (e.g., flat surface) controls; however, proliferation generally was inhibited on the nanofibrous scaffolds although to a lesser extent on the polysaccharide-derived materials compared to PES. In an exception to the trend towards slower growth on the 3D substrates, hNSCs differentiated on the CS nanofibers proliferated faster than the 2D controls and both cell types showed enhanced indication of neuronal differentiation on the CS scaffolds. Together, these results demonstrate beneficial attributes of CS for neural tissue engineering when this polysaccharide is used in the context of the defined 3D topography found in electrospun nanofibers. PMID:24274534

Potential-Energy Surfaces, the Born-Oppenheimer Approximations, and the Franck-Condon Principle: Back to the Roots.

PubMed

Mustroph, Heinz

2016-09-05

The concept of a potential-energy surface (PES) is central to our understanding of spectroscopy, photochemistry, and chemical kinetics. However, the terminology used in connection with the basic approximations is variously, and somewhat confusingly, represented with such phrases as "adiabatic", "Born-Oppenheimer", or "Born-Oppenheimer adiabatic" approximation. Concerning the closely relevant and important Franck-Condon principle (FCP), the IUPAC definition differentiates between a classical and quantum mechanical formulation. Consequently, in many publications we find terms such as "Franck-Condon (excited) state", or a vertical transition to the "Franck-Condon point" with the "Franck-Condon geometry" that relaxes to the excited-state equilibrium geometry. The Born-Oppenheimer approximation and the "classical" model of the Franck-Condon principle are typical examples of misused terms and lax interpretations of the original theories. In this essay, we revisit the original publications of pioneers of the PES concept and the FCP to help stimulate a lively discussion and clearer thinking around these important concepts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mediation of Developmental Risk Factors for Psychosis by White Matter Microstructure in Young Adults With Psychotic Experiences.

PubMed

Drakesmith, Mark; Dutt, Anirban; Fonville, Leon; Zammit, Stanley; Reichenberg, Abraham; Evans, C John; Lewis, Glyn; Jones, Derek K; David, Anthony S

2016-04-01

White matter (WM) abnormalities have been identified in schizophrenia at the earliest stages of the disorder. Individuals in the general population with psychotic experiences (PEs) may show similar changes, suggesting dysfunction due to aberrant neurodevelopment. Studying such people is a powerful means of understanding the nature of neurodevelopmental problems without the confound of clinical management and allows other potential risk factors associated with the schizophrenia spectrum to be taken into account. To compare WM microstructure and myelination in young adults with and without PEs identified from a population-based cohort using diffusion and relaxometry magnetic resonance imaging and to quantify potential mediating effects of WM on several known risk factors for psychosis. In this case-control study, participants were drawn from the UK Avon Longitudinal Study of Parents and Children. Psychotic experiences were assessed using a semistructured interview. Magnetic resonance imaging was carried out at age 20 years in 123 participants who had PEs and 124 individuals serving as controls. Participants with PEs were subdivided into those with operationally defined suspected PEs, definite PEs, and psychotic disorder. Diffusion tensor magnetic resonance imaging and relaxometry-derived myelin water fractions were used to measure WM microstructure and myelination, respectively. Differences in quantitative WM indices were assessed using tract-based spatial statistics. A binary model and a continuum-like ordinal model of PEs were tested. Among the 123 participants who had PEs (mean [SE] age, 20.01 [0.004] years), 37 were male and 86 were female. Among the 124 controls (mean [SE] age, 20.11 [0.004] years), 49 were male and 76 were female. Fractional anisotropy in left frontomedial WM was significantly reduced in individuals with PEs (Montreal Neurological Institute [MNI] coordinates, -18, 37, -2; P = .0046). The ordinal model identified a similar but more widespread effect, with a corresponding increase in radial diffusivity (MNI coordinates, -15, 29, 21; P = .0042). Low birth weight (ρ = -0.155; P = .015) and childhood IQ (ρ = -0.188; P = .003) were associated with the presence of PEs. Results of mediation analysis were consistent with the association between birth weight (21.1% mediation effect; P = 6.20 × 10-3) and childhood IQ (7.9% mediation effect; P = .041) and by PEs being mediated by fractional anisotropy changes in these regions. The results of the study imply the presence of abnormal WM microstructure in young adults with PEs. The results are consistent with the hypothesis that neurodevelopmental factors cause alterations in the cellular composition of WM circuits critical to higher cognitive function. Such alterations may first manifest in childhood as reduced IQ and later contribute to PEs in early adulthood.

Data-Gathering, Belief Flexibility, and Reasoning Across the Psychosis Continuum

PubMed Central

Peters, Emmanuelle; Jackson, Mike; Day, Fern; Garety, Philippa A

2018-01-01

Abstract Background There is evidence for a group of nonclinical individuals with full-blown, persistent psychotic experiences (PEs) but no need-for-care: they are of particular importance in identifying risk and protective factors for clinical psychosis. The aim of this study was to investigate whether reasoning biases are related to PEs or need-for-care. Method Two groups with persistent PEs (clinical; n = 74; nonclinical; n = 92) and a control group without PEs (n = 83) were compared on jumping-to-conclusions (JTC) and belief flexibility. A randomly selected subset of interviews (n = 104) was analyzed to examine differences in experiential and rational reasoning. Results As predicted JTC was more common in the clinical than the other 2 groups. Unexpectedly no group differences were observed between clinical and nonclinical groups on measures of belief flexibility. However, the clinical group was less likely to employ rational reasoning, while the nonclinical group was more likely to use experiential reasoning plus a combination of both types of reasoning processes, compared to the other 2 groups. Conclusions Reasoning biases differ in groups with PEs with and without need-for-care. JTC is associated with need-for-care rather than with PEs. The ability to invoke rational reasoning processes, together with an absence of JTC, may protect against pathological outcomes of persistent PEs. However, marked use of experiential reasoning is associated with the occurrence of PEs in both clinical and nonclinical groups. Implications for theory development, intervention and further research are discussed. PMID:28338872

Accurate Determination of Tunneling-Affected Rate Coefficients: Theory Assessing Experiment.

PubMed

Zuo, Junxiang; Xie, Changjian; Guo, Hua; Xie, Daiqian

2017-07-20

The thermal rate coefficients of a prototypical bimolecular reaction are determined on an accurate ab initio potential energy surface (PES) using ring polymer molecular dynamics (RPMD). It is shown that quantum effects such as tunneling and zero-point energy (ZPE) are of critical importance for the HCl + OH reaction at low temperatures, while the heavier deuterium substitution renders tunneling less facile in the DCl + OH reaction. The calculated RPMD rate coefficients are in excellent agreement with experimental data for the HCl + OH reaction in the entire temperature range of 200-1000 K, confirming the accuracy of the PES. On the other hand, the RPMD rate coefficients for the DCl + OH reaction agree with some, but not all, experimental values. The self-consistency of the theoretical results thus allows a quality assessment of the experimental data.

Occupational Aspirations of State FFA Contest and Award Winners.

ERIC Educational Resources Information Center

Bowen, Blannie E.; Doerfert, David L.

1989-01-01

A study explored the occupational aspirations of 300 (of 503) students with high levels of participation in Future Farmers of America's (FFA) Computers in Agriculture (CIA), Proficiency Award (PA), and Prepared and Extemporaneous Speaking (PES) contests. CIA and PES winners aspired to professional occupations more than PA winners. PES winners…

Decontamination of materials contaminated with Bacillus anthracis and Bacillus thuringiensis Al Hakam spores using PES-Solid, a solid source of peracetic acid.

PubMed

Buhr, T L; Wells, C M; Young, A A; Minter, Z A; Johnson, C A; Payne, A N; McPherson, D C

2013-08-01

To develop test methods and evaluate survival of Bacillus anthracis Ames, B. anthracis ∆Sterne and B. thuringiensis Al Hakam spores after exposure to PES-Solid (a solid source of peracetic acid), including PES-Solid formulations with bacteriostatic surfactants. Spores (≥ 7 logs) were dried on seven different test materials and treated with three different PES-Solid formulations (or preneutralized controls) at room temperature for 15 min. There was either no spore survival or less than 1 log (<10 spores) of spore survival in 56 of 63 test combinations (strain, formulation and substrate). Less than 2.7 logs (<180 spores) survived in the remaining seven test combinations. The highest spore survival rates were seen on water-dispersible chemical agent resistant coating (CARC-W) and Naval ship topcoat (NTC). Electron microscopy and Coulter analysis showed that all spore structures were intact after spore inactivation with PES-Solid. Three PES-Solid formulations inactivated Bacillus spores that were dried on seven different materials. A test method was developed to show that PES-Solid formulations effectively inactivate Bacillus spores on different materials. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Influence of bentonite in polymer membranes for effective treatment of car wash effluent to protect the ecosystem.

PubMed

Kiran, S Aditya; Arthanareeswaran, G; Thuyavan, Y Lukka; Ismail, A F

2015-11-01

In this study, modified polyethersulfone (PES) and cellulose acetate (CA) membranes were used in the treatment of car wash effluent using ultrafiltration. Hydrophilic sulfonated poly ether ether ketone (SPEEK) and bentonite as nanoclay were used as additives for the PES and CA membrane modification. Performances of modified membranes were compared with commercial PES membrane with 10kDa molecular weight cut off (MWCO). The influencing parameters like stirrer speed (250-750rpm) and transmembrane pressure (100-600kPa) (TMP) were varied and their effects were studied as a function of flux. In the treatment of car wash effluent, a higher permeate flux of 52.3L/m(2)h was obtained for modified CA membrane at TMP of 400kPa and stirrer speed of 750rpm. In comparison with modified PES membrane and commercial PES membrane, modified CA membranes showed better performance in terms of flux and flux recovery ratio. The highest COD removal (60%) was obtained for modified CA membrane and a lowest COD removal (47%) was observed for commercial PES membrane. The modified membranes were better at removing COD, turbidity and maintained more stable flux than commercial PES membrane, suggesting they will provide better economic performance in car wash effluent reclamation. Copyright © 2015 Elsevier Inc. All rights reserved.

The association between psychotic experiences and disability: results from the WHO World Mental Health Surveys

PubMed Central

Navarro-Mateu, Fernando; Alonso, Jordi; Lim, Carmen C. W.; Saha, Sukanta; Aguilar-Gaxiola, Sergio; Al-Hamzawi, Ali; Andrade, Laura H.; Bromet, Evelyn J.; Bruffaerts, Ronny; Chatterji, Somnath; Degenhardt, Louisa; de Girolamo, Giovanni; de Jonge, Peter; Fayyad, John; Florescu, Silvia; Gureje, Oye; Haro, Josep M.; Hu, Chiyi; Karam, Elie G.; Kovess-Masfety, Viviane; Lee, Sing; Medina-Mora, Maria E.; Ojagbemi, Akin; Pennell, Beth-Ellen; Posada-Villa, Jose; Scott, Kate M.; Stagnaro, Juan Carlos; Kendler, Kenneth S.; Kessler, Ronald C.; McGrath, John J.

2017-01-01

Objective While psychotic experiences (PEs) are known to be associated with a range of mental and general medical disorders, little is known about the association between PEs and measures of disability. We aimed to investigate this question using the World Mental Health surveys. Method Lifetime occurrences of 6 types of PEs were assessed along with 21 mental disorders and 14 general medical conditions. Disability was assessed with a modified version of the WHO Disability Assessment Schedule. Descriptive statistics and logistic regression models were used to investigate the association between PEs and high disability scores (top quartile) with various adjustments. Results Respondents with PEs were more likely to have top quartile scores on global disability than respondents without PEs (19.1% vs. 7.5%; χ2 = 190.1, p<.001) as well as greater likelihood of cognitive, social, and role impairment. Relationships persisted in each adjusted model. A significant dose-response relationship was also found for the PE type measures with most of these outcomes. Conclusions Psychotic experiences are associated with disability measures with a dose response relationship. These results are consistent with the view that PEs are associated with disability regardless of the presence of comorbid mental or general medical disorders. PMID:28542726

The association between psychotic experiences and disability: results from the WHO World Mental Health Surveys.

PubMed

Navarro-Mateu, F; Alonso, J; Lim, C C W; Saha, S; Aguilar-Gaxiola, S; Al-Hamzawi, A; Andrade, L H; Bromet, E J; Bruffaerts, R; Chatterji, S; Degenhardt, L; de Girolamo, G; de Jonge, P; Fayyad, J; Florescu, S; Gureje, O; Haro, J M; Hu, C; Karam, E G; Kovess-Masfety, V; Lee, S; Medina-Mora, M E; Ojagbemi, A; Pennell, B-E; Piazza, M; Posada-Villa, J; Scott, K M; Stagnaro, J C; Xavier, M; Kendler, K S; Kessler, R C; McGrath, J J

2017-07-01

While psychotic experiences (PEs) are known to be associated with a range of mental and general medical disorders, little is known about the association between PEs and measures of disability. We aimed to investigate this question using the World Mental Health surveys. Lifetime occurrences of six types of PEs were assessed along with 21 mental disorders and 14 general medical conditions. Disability was assessed with a modified version of the WHO Disability Assessment Schedule. Descriptive statistics and logistic regression models were used to investigate the association between PEs and high disability scores (top quartile) with various adjustments. Respondents with PEs were more likely to have top quartile scores on global disability than respondents without PEs (19.1% vs. 7.5%; χ 2  = 190.1, P < 0.001) as well as greater likelihood of cognitive, social, and role impairment. Relationships persisted in each adjusted model. A significant dose-response relationship was also found for the PE type measures with most of these outcomes. Psychotic experiences are associated with disability measures with a dose-response relationship. These results are consistent with the view that PEs are associated with disability regardless of the presence of comorbid mental or general medical disorders. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Enhancement of polyethersulfone (PES) membrane performance by modification with rice husk nanosilica for removal of organic matter in water

NASA Astrophysics Data System (ADS)

Mulyati, S.; Armando, M. A.; Mawardi, H.; Azmi, F. A.; Pratiwi, W. P.; Fadzlina, A.; Akbar, R.; Syawaliah

2018-03-01

This paper reports the effects of rice husk nanosilica addition on the performance of polyethersulfone (PES) membrane. Polyethersulfone membrane (PES) was fabricated by using N-methyl-2-pyrolidone (NMP) as a solvent and rice husk nanosilica as a modifying agent. The influence of the rice husk nanosilica additive on the characteristics and performance of the membrane has been studied. Scanning Electron Microscopy (SEM) analysis confirmed that the manufactured membrane has an asymmetric morphological structure consisting of two layers. The upper part of the membrane is a thin layer, meanwhile in the bottom side is a porous layer. The addition of 5% nanosilica resulting a PES membrane to have a bigger porous than that of pristine PES. The pure water flux of nanosilica-modified membranes were greater in comparison to the pure water flux of unmodified PES membrane. The performance of all membranes were evaluated on humic acid removal. The highest selectivity was showcased by pure PES membrane. The introduction of rice husk nanosilica additive to the membrane declined the selectivity of the membrane to humic acid in the feed solution. This is caused by the pores enlargement and enhanced hydrophilicity of the membrane after modification with rice husk biosilica.

Determination of phthalate esters in drinking water and edible vegetable oil samples by headspace solid phase microextraction using graphene/polyvinylchloride nanocomposite coated fiber coupled to gas chromatography-flame ionization detector.

PubMed

Amanzadeh, Hatam; Yamini, Yadollah; Moradi, Morteza; Asl, Yousef Abdossalmi

2016-09-23

In the current study, a graphene/polyvinylchloride nanocomposite was successfully coated on a stainless steel substrate by a simple dip coating process and used as a novel headspace solid phase microextraction (HS-SPME) fiber for the extraction of phthalate esters (PEs) from drinking water and edible vegetable oil samples. The prepared SPME fibers exhibited high extractability for PEs (due to the dominant role of π-π stacking interactions and hydrophobic effects) yielding good sensitivity and precision when followed by a gas chromatograph with a flame ionization detector (GC-FID). The optimization strategy of the extraction process was carried out using the response surface method based on a central composite design. The developed method gave a low limit of detection (0.06-0.08μgL(-1)) and good linearity (0.2-100μgL(-1)) for the determination of the PEs under the optimized conditions (extraction temperature, 70±1°C; extraction time, 35min; salt concentration, 30% w/v; stirring rate, 900rpm; desorption temperature, 230°C; and desorption time, 4min) whereas the repeatability and fiber-to-fiber reproducibility were in the range 6.1-7.8% and 8.9-10.2%, respectively. Finally, the proposed method was successfully applied to the analysis of PEs in drinking water and edible oil samples with good recoveries (87-112%) and satisfactory precisions (RSDs<8.3%), indicating the absence of matrix effects in the proposed HS-SPME method. Copyright © 2016 Elsevier B.V. All rights reserved.

Depth- and momentum- resolved electronic structure at buried oxide interfaces from standing-wave angle-resolved photoemission

NASA Astrophysics Data System (ADS)

Fadley, Charles

2015-03-01

It is clear that interfaces in complex oxide heterostructures often represent emergent materials that possess surprising properties not associated with the parent oxides, such as two-dimensional electron gases (2DEGs), superconductivity, and magnetism. A detailed knowledge of the composition, atomic structure, and electronic structure through such interfaces is thus critical. Photomission (PES) and angle-resolved photoemission (ARPES) represent techniques of choice for such studies, but have certain limitations in being too surface sensitive and in not being able to focus specifically on buried interfaces or heterostructure layers. In this talk, I will discuss combining two newer elements of PES/ARPES to deal with this challenge: - the use of soft x-rays in the ca. few hundred-to-2000 eV regime, or even into the true hard x-ray regime, to probe more deeply into the structure, and - tailoring of the x-ray intensity profile into a strong standing wave (SW) through reflection from a multilayer heterostructure to provide much enhanced depth resolution. The relative advantages of soft/hard x-ray PES and ARPES and their complementarity to conventional VUV ARPES in the ca. 5-150 eV regime will be considered. As illustrative examples, by combining SW-PES and SW-ARPES, it has been possible to measure for the first time the detailed concentration profiles and momentum-resolved electronic structure at the SrTiO3/La0.67Sr0.33MnO3 interface and to directly measure the depth profile of the 2DEG at SrTiO3/GdTiO3 interfaces. Future directions for such measurements will also be discussed. Supported by US DOE Contract No. DE-AC02-05CH11231, ARO-MURI Grant W911-NF-09-1-0398, and the PALM-APTCOM Project (France).

Full-dimensional global potential energy surfaces describing abstraction and exchange for the H + H{sub 2}S reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Dandan; Li, Jun, E-mail: jli15@cqu.edu.edu

2016-07-07

For the H + H{sub 2}S system, ∼34 000 data points are sampled over a large configuration space including both abstraction and exchange channels, and calculated at the level of explicitly correlated unrestricted coupled cluster method with singles, doubles, and perturbative triples excitations with the augmented correlation-consistent polarized triple zeta basis set (UCCSD(T)-F12a/aug-cc-pVTZ). The data set was fit using the newly proposed permutation invariant polynomial-neural network (PIP-NN) method with three different vectors as the input: two redundant sets of PIPs, one with the maximum order four (PES-I) and one with the maximum order three (PES-II), and nine non-redundant PIPs (PES-III). Allmore » these PESs show small fitting errors and essentially the same performance in representing the title system. Various kinetics and dynamical properties are calculated using the tunneling corrected transition state theory and quasi-classical trajectory, and compared with available experimental results. At a collision energy of 10 kcal/mol, both the H{sub 2} and SH products are found to be internally cold, with ∼20% of H{sub 2} at its first vibrational excited state, while SH is essentially a spectator. The angular distributions of the products are mainly in backward with considerable contributions from sideway direction. In addition, analytical partial derivatives of any PIP-NN PES with respect to the coordinates of atoms are derived by making use of the monomial symmetrization algorithm [Z. Xie and J. M. Bowman, J. Chem. Theory Comput. 6, 26–34 (2010)]. It can not only accelerate the evaluation of the derivatives, but also improve the energy convergence significantly.« less

Structural, biological and biophysical properties of glycated and glycoxidized phosphatidylethanolamines

PubMed Central

Annibal, Andrea; Riemer, Thomas; Jovanovic, Olga; Westphal, Dennis; Griesser, Eva; Pohl, Elena E.; Schiller, Jürgen; Hoffmann, Ralf; Fedorova, Maria

2018-01-01

Glycation and glycoxidation of proteins and peptides have been intensively studied and are considered as reliable diagnostic biomarkers of hyperglycemia and early stages of type II diabetes. However, glucose can also react with primary amino groups present in other cellular components, such as aminophospholipids (aminoPLs). Although it is proposed that glycated aminoPLs can induce many cellular responses and contribute to the development and progression of diabetes, the routes of their formation and their biological roles are only partially revealed. The same is true for the influence of glucose-derived modifications on the biophysical properties of PLs. Here we studied structural, signaling, and biophysical properties of glycated and glycoxidized phosphatidylethanolamines (PEs). By combining high resolution mass spectrometry and nuclear magnetic resonance spectroscopy it was possible to deduce the structures of several intermediates indicating an oxidative cleavage of the Amadori product yielding glycoxidized PEs including advanced glycation end products, such as carboxyethyl- and carboxymethyl-ethanolamines. The pro-oxidative role of glycated PEs was demonstrated and further associated with several cellular responses including activation of NFκB signaling pathways. Label free proteomics indicated significant alterations in proteins regulating cellular metabolisms. Finally, the biophysical properties of PL membranes changed significantly upon PE glycation, such as melting temperature (Tm), membrane surface charge, and ion transport across the phospholipid bilayer. PMID:27012418

Work function variation of MoS{sub 2} atomic layers grown with chemical vapor deposition: The effects of thickness and the adsorption of water/oxygen molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jong Hun; Kim, Jae Hyeon; Park, Jeong Young, E-mail: peterlee@skku.edu, E-mail: jeongypark@kaist.ac.kr

2015-06-22

The electrical properties of two-dimensional atomic sheets exhibit remarkable dependences on layer thickness and surface chemistry. Here, we investigated the variation of the work function properties of MoS{sub 2} films prepared with chemical vapor deposition (CVD) on SiO{sub 2} substrates with the number of film layers. Wafer-scale CVD MoS{sub 2} films with 2, 4, and 12 layers were fabricated on SiO{sub 2}, and their properties were evaluated by using Raman and photoluminescence spectroscopies. In accordance with our X-ray photoelectron spectroscopy results, our Kelvin probe force microscopy investigation found that the surface potential of the MoS{sub 2} films increases by ∼0.15 eVmore » when the number of layers is increased from 2 to 12. Photoemission spectroscopy (PES) with in-situ annealing under ultra high vacuum conditions was used to directly demonstrate that this work function shift is associated with the screening effects of oxygen or water molecules adsorbed on the film surface. After annealing, it was found with PES that the surface potential decreases by ∼0.2 eV upon the removal of the adsorbed layers, which confirms that adsorbed species have a role in the variation in the work function.« less

Human Milk Plasmalogens Are Highly Enriched in Long-Chain PUFAs.

PubMed

Moukarzel, Sara; Dyer, Roger A; Keller, Bernd O; Elango, Rajavel; Innis, Sheila M

2016-11-01

Human milk contains unique glycerophospholipids, including ethanolamine-containing plasmalogens (Pls-PEs) in the milk fat globule membrane, which have been implicated in infant brain development. Brain Pls-PEs accumulate postnatally and are enriched in long-chain polyunsaturated fatty acids (LC-PUFAs), particularly docosahexaenoic acid (DHA). Fatty acid (FA) composition of Pls-PEs in milk is poorly understood because of the analytical challenges in separating Pls-PEs from other phospholipids in the predominating presence of triacylglycerols. The variability of Pls-PE FAs and the potential role of maternal diet remain unknown. Our primary objectives were to establish improved methodology for extracting Pls-PEs from human milk, enabling FA analysis, and to compare FA composition between Pls-PEs and 2 major milk phospholipids, phosphatidylcholine and phosphatidylethanolamine. Our secondary objective was to explore associations between maternal DHA intake and DHA in milk phospholipids and variability in phospholipid-DHA within a woman. Mature milk was collected from 25 women, with 4 providing 3 milk samples on 3 separate days. Lipids were extracted, and phospholipids were removed by solid phase extraction. Pls-PEs were separated by using normal-phase HPLC, recovered and analyzed for FAs by GLC. Diet was assessed by using a validated food-frequency questionnaire. Pls-PE concentration in human milk was significantly higher in LC-PUFAs than phosphatidylethanolamine and phosphatidylcholine, including arachidonic acid (AA) and DHA. The mean ± SD concentration of AAs in Pls-PEs was ∼2.5-fold higher than in phosphatidylethanolamine (10.5 ± 1.71 and 3.82 ± 0.92 g/100 g, respectively). DHA in Pls-PEs varied across women (0.95-6.51 g/100 g), likely independent of maternal DHA intake. Pls-PE DHA also varied within a woman across days (CV ranged from 9.8% to 28%). Human milk provides the infant with LC-PUFAs from multiple lipid pools, including a source from Pls-PEs. The biological determinants of Pls-PE FAs and physiological relevance to the breastfed infant remain to be elucidated. © 2016 American Society for Nutrition.

Potential energy surface, dipole moment surface and the intensity calculations for the 10 μm, 5 μm and 3 μm bands of ozone

NASA Astrophysics Data System (ADS)

Polyansky, Oleg L.; Zobov, Nikolai F.; Mizus, Irina I.; Kyuberis, Aleksandra A.; Lodi, Lorenzo; Tennyson, Jonathan

2018-05-01

Monitoring ozone concentrations in the Earth's atmosphere using spectroscopic methods is a major activity which undertaken both from the ground and from space. However there are long-running issues of consistency between measurements made at infrared (IR) and ultraviolet (UV) wavelengths. In addition, key O3 IR bands at 10 μm, 5 μm and 3 μm also yield results which differ by a few percent when used for retrievals. These problems stem from the underlying laboratory measurements of the line intensities. Here we use quantum chemical techniques, first principles electronic structure and variational nuclear-motion calculations, to address this problem. A new high-accuracy ab initio dipole moment surface (DMS) is computed. Several spectroscopically-determined potential energy surfaces (PESs) are constructed by fitting to empirical energy levels in the region below 7000 cm-1 starting from an ab initio PES. Nuclear motion calculations using these new surfaces allow the unambiguous determination of the intensities of 10 μm band transitions, and the computation of the intensities of 10 μm and 5 μm bands within their experimental error. A decrease in intensities within the 3 μm is predicted which appears consistent with atmospheric retrievals. The PES and DMS form a suitable starting point both for the computation of comprehensive ozone line lists and for future calculations of electronic transition intensities.

Anti-thrombogenicity and permeability of polyethersulfone hollow fiber membrane with sulfonated alginate toward blood purification.

PubMed

Salimi, Esmaeil; Ghaee, Azadeh; Ismail, Ahmad Fauzi; Karimi, Majid

2018-04-30

The main aim of this study was to evaluate the suitability of sulfonated alginate as a modifying agent to enhance the hemocompatibility of self-fabricated polyethersulfone (PES) hollow fiber membrane for blood detoxification. Sodium alginate was sulfonated with a degree of 0.6 and immobilized on the membrane via surface amination and using glutaraldehyde as cross-linking agent. Coating layer not only improved the membrane surface hydrophilicity, but also induced -39.2 mV negative charges on the surface. Water permeability of the modified membrane was enhanced from 67 to 95 L/m 2 ·h·bar and flux recovery ratio increased more than 2-fold. Furthermore, the modified membrane presented higher platelet adhesion resistance (reduced by more than 90%) and prolonged coagulation time (35 s for APTT and 14 s for PT) in comparison with the pristine PES hollow fiber membrane, which verified the improved anti-thrombogenicity of the modified membrane. On the other hand, obtained membrane after 3 h coating could remove up-to 60% of the uremic toxins. According to the obtained data, sulfonated alginate can be a promising modifying agent for the future blood-contacting membrane and specially blood purification issues. Copyright © 2018 Elsevier B.V. All rights reserved.

Data-Gathering, Belief Flexibility, and Reasoning Across the Psychosis Continuum.

PubMed

Ward, Thomas; Peters, Emmanuelle; Jackson, Mike; Day, Fern; Garety, Philippa A

2018-01-13

There is evidence for a group of nonclinical individuals with full-blown, persistent psychotic experiences (PEs) but no need-for-care: they are of particular importance in identifying risk and protective factors for clinical psychosis. The aim of this study was to investigate whether reasoning biases are related to PEs or need-for-care. Two groups with persistent PEs (clinical; n = 74; nonclinical; n = 92) and a control group without PEs (n = 83) were compared on jumping-to-conclusions (JTC) and belief flexibility. A randomly selected subset of interviews (n = 104) was analyzed to examine differences in experiential and rational reasoning. As predicted JTC was more common in the clinical than the other 2 groups. Unexpectedly no group differences were observed between clinical and nonclinical groups on measures of belief flexibility. However, the clinical group was less likely to employ rational reasoning, while the nonclinical group was more likely to use experiential reasoning plus a combination of both types of reasoning processes, compared to the other 2 groups. Reasoning biases differ in groups with PEs with and without need-for-care. JTC is associated with need-for-care rather than with PEs. The ability to invoke rational reasoning processes, together with an absence of JTC, may protect against pathological outcomes of persistent PEs. However, marked use of experiential reasoning is associated with the occurrence of PEs in both clinical and nonclinical groups. Implications for theory development, intervention and further research are discussed. © The Author 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center.

Ultrasound evaluation of foot muscles and plantar fascia in pes planus.

PubMed

Angin, Salih; Crofts, Gillian; Mickle, Karen J; Nester, Christopher J

2014-01-01

Multiple intrinsic and extrinsic soft tissue structures that apply forces and support the medial longitudinal arch have been implicated in pes planus. These structures have common functions but their interaction in pes planus is not fully understood. The aim of this study was to compare the cross-sectional area (CSA) and thickness of the intrinsic and extrinsic foot muscles and plantar fascia thickness between normal and pes planus feet. Forty-nine adults with a normal foot posture and 49 individuals with pes planus feet were recruited from a university population. Images of the flexor digitorum longus (FDL), flexor hallucis longus (FHL), peroneus longus and brevis (PER), flexor hallucis brevis (FHB), flexor digitorum brevis (FDB) and abductor hallucis (AbH) muscles and the plantar fascia were obtained using a Venue 40 ultrasound system with a 5-13 MHz transducer. The CSA and thickness of AbH, FHB and PER muscles were significantly smaller (AbH -12.8% and -6.8%, FHB -8.9% and -7.6%, PER -14.7% and -10%), whilst FDL (28.3% and 15.2%) and FHL (24% and 9.8%) were significantly larger in the pes planus group. The middle (-10.6%) and anterior (-21.7%) portions of the plantar fascia were thinner in pes planus group. Greater CSA and thickness of the extrinsic muscles might reflect compensatory activity to support the MLA if the intrinsic foot muscle function has been compromised by altered foot structure. A thinner plantar fascia suggests reduced load bearing, and regional variations in structure and function in feet with pes planus. Copyright © 2014 Elsevier B.V. All rights reserved.

Development and validation of the patient evaluation scale (PES) for primary health care in Nigeria.

PubMed

Ogaji, Daprim S; Giles, Sally; Daker-White, Gavin; Bower, Peter

2017-03-01

Questionnaires developed for patient evaluation of the quality of primary care are often focussed on primary care systems in developed countries. Aim To report the development and validation of the patient evaluation scale (PES) designed for use in the Nigerian primary health care context. An iterative process was used to develop and validate the questionnaire using patients attending 28 primary health centres across eight states in Nigeria. The development involved literature review, patient interviews, expert reviews, cognitive testing with patients and waves of quantitative cross-sectional surveys. The questionnaire's content validity, internal structures, acceptability, reliability and construct validity are reported. Findings The full and shortened version of PES with 27 and 18 items, respectively, were developed through these process. The low item non-response from the serial cross-sectional surveys depicts questionnaire's acceptability among the local population. PES-short form (SF) has Cronbach's α of 0.87 and three domains (codenamed 'facility', 'organisation' and 'health care') with Cronbach's αs of 0.78, 0.79 and 0.81, respectively. Items in the multi-dimensional questionnaire demonstrated adequate convergent and discriminant properties. PES-SF scores show significant positive correlation with scores of the full PES and also discriminated population groups in support of a priori hypotheses. The PES and PES-SF contain items that are relevant to the needs of patients in Nigeria. The good measurement properties of the questionnaire demonstrates its potential usefulness for patient-focussed quality improvement activities in Nigeria. There is still need to translate these questionnaires into major languages in Nigeria and assess their validity against external quality criteria.

Photoelectron Spectroscopy in Advanced Placement Chemistry

ERIC Educational Resources Information Center

Benigna, James

2014-01-01

Photoelectron spectroscopy (PES) is a new addition to the Advanced Placement (AP) Chemistry curriculum. This article explains the rationale for its inclusion, an overview of how the PES instrument records data, how the data can be analyzed, and how to include PES data in the course. Sample assessment items and analysis are included, as well as…

Computational study of collisions between O({sup 3}P) and NO({sup 2}Π) at temperatures relevant to the hypersonic flight regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castro-Palacio, Juan Carlos; Nagy, Tibor; Meuwly, Markus, E-mail: m.meuwly@unibas.ch

2014-10-28

Reactions involving N and O atoms dominate the energetics of the reactive air flow around spacecraft when reentering the atmosphere in the hypersonic flight regime. For this reason, the thermal rate coefficients for reactive processes involving O({sup 3}P) and NO({sup 2}Π) are relevant over a wide range of temperatures. For this purpose, a potential energy surface (PES) for the ground state of the NO{sub 2} molecule is constructed based on high-level ab initio calculations. These ab initio energies are represented using the reproducible kernel Hilbert space method and Legendre polynomials. The global PES of NO{sub 2} in the ground statemore » is constructed by smoothly connecting the surfaces of the grids of various channels around the equilibrium NO{sub 2} geometry by a distance-dependent weighting function. The rate coefficients were calculated using Monte Carlo integration. The results indicate that at high temperatures only the lowest A-symmetry PES is relevant. At the highest temperatures investigated (20 000 K), the rate coefficient for the “O1O2+N” channel becomes comparable (to within a factor of around three) to the rate coefficient of the oxygen exchange reaction. A state resolved analysis shows that the smaller the vibrational quantum number of NO in the reactants, the higher the relative translational energy required to open it and conversely with higher vibrational quantum number, less translational energy is required. This is in accordance with Polanyi's rules. However, the oxygen exchange channel (NO2+O1) is accessible at any collision energy. Finally, this work introduces an efficient computational protocol for the investigation of three-atom collisions in general.« less

Computational study of collisions between O(3P) and NO(2Π) at temperatures relevant to the hypersonic flight regime.

PubMed

Castro-Palacio, Juan Carlos; Nagy, Tibor; Bemish, Raymond J; Meuwly, Markus

2014-10-28

Reactions involving N and O atoms dominate the energetics of the reactive air flow around spacecraft when reentering the atmosphere in the hypersonic flight regime. For this reason, the thermal rate coefficients for reactive processes involving O((3)P) and NO((2)Π) are relevant over a wide range of temperatures. For this purpose, a potential energy surface (PES) for the ground state of the NO2 molecule is constructed based on high-level ab initio calculations. These ab initio energies are represented using the reproducible kernel Hilbert space method and Legendre polynomials. The global PES of NO2 in the ground state is constructed by smoothly connecting the surfaces of the grids of various channels around the equilibrium NO2 geometry by a distance-dependent weighting function. The rate coefficients were calculated using Monte Carlo integration. The results indicate that at high temperatures only the lowest A-symmetry PES is relevant. At the highest temperatures investigated (20,000 K), the rate coefficient for the "O1O2+N" channel becomes comparable (to within a factor of around three) to the rate coefficient of the oxygen exchange reaction. A state resolved analysis shows that the smaller the vibrational quantum number of NO in the reactants, the higher the relative translational energy required to open it and conversely with higher vibrational quantum number, less translational energy is required. This is in accordance with Polanyi's rules. However, the oxygen exchange channel (NO2+O1) is accessible at any collision energy. Finally, this work introduces an efficient computational protocol for the investigation of three-atom collisions in general.

The long-term outcome of tick-borne encephalitis in Central Europe.

PubMed

Bogovič, Petra; Stupica, Daša; Rojko, Tereza; Lotrič-Furlan, Stanka; Avšič-Županc, Tatjana; Kastrin, Andrej; Lusa, Lara; Strle, Franc

2018-02-01

Information on the long-term outcome of tick-borne encephalitis (TBE) is limited. To assess the frequency and severity of post-encephalitic syndrome (PES) at different time points after TBE, and to determine the parameters associated with unfavourable outcome. Adult patients diagnosed with TBE in Slovenia in the period 2007-2012 were followed-up for 12 months and also examined 2-7 years after TBE. Each patient was asked to refer a person of similar age without a history of TBE to serve as control. A total of 420 patients and 295 control persons participated in the study. The proportion of patients with PES (defined as the presence of ≥ 2 subjective symptoms that newly developed or worsened since the onset of TBE and which had no other known medical explanation, and/or ≥ 1 objective neurological sign) was higher (P < 0.001) at the follow-up visit 6 months after the acute illness (127/304, 42%, 95% CI: 36-47%) than at 12 months (68/207, 33%, 95% CI: 26-40%); the proportion at 12 months was the same as at 2-7 years after TBE (137/420, 33%, 95% CI: 28-37%). However, the proportion of severe PES at the last two time points differed (9.7% vs 4.3%, P = 0.008). Multivariate logistic regression showed that unfavourable outcome at 6 months was associated with CSF leukocyte count (OR = 1.003, 95% CI: 1.001-1.005%, P = 0.017), at 12 months with the disease outcome at 6 months (OR = 115.473, 95% CI: 26.009-512.667%, P < 0.001), and at the final visit with disease outcome at 6 months (OR = 3.808, 95% CI: 1.151-12.593%, P = 0.028) and 12 months (OR = 26.740, 95% CI: 8.648-82.680%, P < 0.001). Unspecific symptoms that occurred within the four weeks before the final examination were more frequent and more constant in patients than in the control group. The frequency of PES diminished over time and stabilized 12 months after the acute illness, whereas the severity of PES continued to decline. Unfavourable outcomes at 12 months and at the final visit were strongly associated with the presence of PES at previous time points. Copyright © 2017 Elsevier GmbH. All rights reserved.

What story does geographic separation of insular bats tell? A case study on Sardinian rhinolophids.

PubMed

Russo, Danilo; Di Febbraro, Mirko; Rebelo, Hugo; Mucedda, Mauro; Cistrone, Luca; Agnelli, Paolo; De Pasquale, Pier Paolo; Martinoli, Adriano; Scaravelli, Dino; Spilinga, Cristiano; Bosso, Luciano

2014-01-01

Competition may lead to changes in a species' environmental niche in areas of sympatry and shifts in the niche of weaker competitors to occupy areas where stronger ones are rarer. Although mainland Mediterranean (Rhinolophus euryale) and Mehely's (R. mehelyi) horseshoe bats mitigate competition by habitat partitioning, this may not be true on resource-limited systems such as islands. We hypothesize that Sardinian R. euryale (SAR) have a distinct ecological niche suited to persist in the south of Sardinia where R. mehelyi is rarer. Assuming that SAR originated from other Italian populations (PES)--mostly allopatric with R. mehelyi--once on Sardinia the former may have undergone niche displacement driven by R. mehelyi. Alternatively, its niche could have been inherited from a Maghrebian source population. We: a) generated Maxent Species Distribution Models (SDM) for Sardinian populations; b) calibrated a model with PES occurrences and projected it to Sardinia to see whether PES niche would increase R. euryale's sympatry with R. mehelyi; and c) tested for niche similarity between R. mehelyi and PES, PES and SAR, and R. mehelyi and SAR. Finally we predicted R. euryale's range in Northern Africa both in the present and during the Last Glacial Maximum (LGM) by calibrating SDMs respectively with SAR and PES occurrences and projecting them to the Maghreb. R. mehelyi and PES showed niche similarity potentially leading to competition. According to PES' niche, R. euryale would show a larger sympatry with R. mehelyi on Sardinia than according to SAR niche. Such niches have null similarity. The current and LGM Maghrebian ranges of R. euryale were predicted to be wide according to SAR's niche, negligible according to PES' niche. SAR's niche allows R. euryale to persist where R. mehelyi is rarer and competition probably mild. Possible explanations may be competition-driven niche displacement or Maghrebian origin.

Effects of aperture averaging and beam width on a partially coherent Gaussian beam over free-space optical links with turbulence and pointing errors.

PubMed

Lee, It Ee; Ghassemlooy, Zabih; Ng, Wai Pang; Khalighi, Mohammad-Ali; Liaw, Shien-Kuei

2016-01-01

Joint effects of aperture averaging and beam width on the performance of free-space optical communication links, under the impairments of atmospheric loss, turbulence, and pointing errors (PEs), are investigated from an information theory perspective. The propagation of a spatially partially coherent Gaussian-beam wave through a random turbulent medium is characterized, taking into account the diverging and focusing properties of the optical beam as well as the scintillation and beam wander effects. Results show that a noticeable improvement in the average channel capacity can be achieved with an enlarged receiver aperture in the moderate-to-strong turbulence regime, even without knowledge of the channel state information. In particular, it is observed that the optimum beam width can be reduced to improve the channel capacity, albeit the presence of scintillation and PEs, given that either one or both of these adverse effects are least dominant. We show that, under strong turbulence conditions, the beam width increases linearly with the Rytov variance for a relatively smaller PE loss but changes exponentially with steeper increments for higher PE losses. Our findings conclude that the optimal beam width is dependent on the combined effects of turbulence and PEs, and this parameter should be adjusted according to the varying atmospheric channel conditions. Therefore, we demonstrate that the maximum channel capacity is best achieved through the introduction of a larger receiver aperture and a beam-width optimization technique.

Core level line shapes and surface band structures of Sn/Ge(111) and Sn/Si(111)

NASA Astrophysics Data System (ADS)

Uhrberg, Roger

2001-03-01

We have performed a comparative study of Sn/Ge(111) and the closely related Sn/Si(111) system, using photoelectron spectroscopy (PES) and low energy electron diffraction (LEED). In similarity with the results from the Sn/Ge(111) surface, the Sn 4d spectra from Sn/Si(111) exhibit two major components and the valence band spectra show two surface state bands at both room temperature (RT) and 70 K. These features, which have been associated with the low temperature 3x3 phase in the case of Sn/Ge(111), are not expected for the rt3xrt3 RT surfaces. In contrast to Sn/Ge(111), we do not observe any transition to a 3x3 phase in LEED for Sn/Si(111) at temperatures down to 70 K (the lowest temperature in this study). Despite the absence of a 3x3 phase for Sn/Si(111) the core-level and the valence band data are very similar to those of Sn/Ge(111). The Sn 4d spectra show, however, one interesting difference. The intensity ratio of the two Sn 4d components is reversed for the Sn/Si(111) surface compared the Ge counterpart. This and the other PES results will be discussed in terms of the two different types of 3x3 periodicities that have been reported to be induced by substitutional defects on the Sn/Ge(111) surface [1]. [1] A.V. Melechko et al., Phys. Rev. B61, 2235 (2000)

Childhood abuse and psychotic experiences - evidence for mediation by adulthood adverse life events.

PubMed

Bhavsar, V; Boydell, J; McGuire, P; Harris, V; Hotopf, M; Hatch, S L; MacCabe, J H; Morgan, C

2017-10-09

We have previously reported an association between childhood abuse and psychotic experiences (PEs) in survey data from South East London. Childhood abuse is related to subsequent adulthood adversity, which could form one pathway to PEs. We aimed to investigate evidence of mediation of the association between childhood abuse and PEs by adverse life events. Data were analysed from the South East London Community Health Study (SELCoH, n = 1698). Estimates of the total effects on PEs of any physical or sexual abuse while growing up were partitioned into direct (i.e. unmediated) and indirect (total and specific) effects, mediated via violent and non-violent life events. There was strong statistical evidence for direct (OR 1.58, 95% CI: 1.19-2.1) and indirect (OR 1.51, 95% CI: 1.32-1.72) effects of childhood abuse on PEs after adjustment for potential confounders, indicating partial mediation of this effect via violent and non-violent life events. An estimated 47% of the total effect of abuse on PEs was mediated via adulthood adverse life events, of which violent life events made up 33% and non-violent life events the remaining 14%. The association between childhood abuse and PEs is partly mediated through the experience of adverse life events in adulthood. There is some evidence that a larger proportion of this effect was mediated through violent life events than non-violent life events.

Nanoplasmonic Quantification of Tumor-derived Extracellular Vesicles in Plasma Microsamples for Diagnosis and Treatment Monitoring

PubMed Central

Liang, Kai; Liu, Fei; Fan, Jia; Sun, Dali; Liu, Chang; Lyon, Christopher J.; Bernard, David W.; Li, Yan; Yokoi, Kenji; Katz, Matthew H.; Koay, Eugene J.; Zhao, Zhen; Hu, Ye

2017-01-01

Tumour-derived extracellular vesicles (EVs) are of increasing interest as a resource of diagnostic biomarkers. However, most EV assays require large samples, are time-consuming, low-throughput and costly, and thus impractical for clinical use. Here, we describe a rapid, ultrasensitive and inexpensive nanoplasmon-enhanced scattering (nPES) assay that directly quantifies tumor-derived EVs from as little as 1 μL of plasma. The assay uses the binding of antibody-conjugated gold nanospheres and nanorods to EVs captured by EV-specific antibodies on a sensor chip to produce a local plasmon effect that enhances tumour-derived EV detection sensitivity and specificity. We identified a pancreatic cancer EV biomarker, ephrin type-A receptor 2 (EphA2), and demonstrate that an nPES assay for EphA2-EVs distinguishes pancreatic cancer patients from pancreatitis patients and healthy subjects. EphA2-EVs were also informative in staging tumour progression and in detecting early responses to neoadjuvant therapy, with better performance than a conventional enzyme-linked immunosorbent assay. The nPES assay can be easily refined for clinical use, and readily adapted for diagnosis and monitoring of other conditions with disease-specific EV biomarkers. PMID:28791195

Identifying the critical physical demanding tasks of paramedic work: Towards the development of a physical employment standard.

PubMed

Fischer, Steven L; Sinden, Kathryn E; MacPhee, Renee S

2017-11-01

Public safety related occupations including police, fire and military commonly apply physical employment standard (PES) to facilitate job matching, an approach to evaluate if candidates demonstrate acceptable physical capabilities as required to perform the job safely and effectively. In Canada, paramedics remain as one of the few public safety occupations without an evidence-based, validated PES. The purpose of this study was to document and describe the physical demands of paramedic work and to identify the most physically demanding tasks. These outcomes are essential to inform the design and development of an evidence-based PES for the paramedic sector. Physical demands of paramedic work were documented and described using a direct observation-based task analysis technique. Five paramedic's were trained to document the physical demands of their work, then applied their training to observe more than 90 calls over the course of 20 full 12-h work shifts. Physical demands data were then listed in a survey, administered service-wide, where 155 frontline paramedics identified critically demanding tasks and rank-ordered physical demands from not physically demanding to very strongly demanding. Critically important and physically demanding tasks were identified such as: transferring a patient; loading or unloading a stretcher in to or out of the ambulance; performing CPR; and, raising and lowering a stretcher. It is important that a paramedic-based PES evaluate a candidate's physical capabilities to perform the critical and physically demanding tasks identified in this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

A cerebellar thalamic cortical circuit for error-related cognitive control.

PubMed

Ide, Jaime S; Li, Chiang-shan R

2011-01-01

Error detection and behavioral adjustment are core components of cognitive control. Numerous studies have focused on the anterior cingulate cortex (ACC) as a critical locus of this executive function. Our previous work showed greater activation in the dorsal ACC and subcortical structures during error detection, and activation in the ventrolateral prefrontal cortex (VLPFC) during post-error slowing (PES) in a stop signal task (SST). However, the extent of error-related cortical or subcortical activation across subjects was not correlated with VLPFC activity during PES. So then, what causes VLPFC activation during PES? To address this question, we employed Granger causality mapping (GCM) and identified regions that Granger caused VLPFC activation in 54 adults performing the SST during fMRI. These brain regions, including the supplementary motor area (SMA), cerebellum, a pontine region, and medial thalamus, represent potential targets responding to errors in a way that could influence VLPFC activation. In confirmation of this hypothesis, the error-related activity of these regions correlated with VLPFC activation during PES, with the cerebellum showing the strongest association. The finding that cerebellar activation Granger causes prefrontal activity during behavioral adjustment supports a cerebellar function in cognitive control. Furthermore, multivariate GCA described the "flow of information" across these brain regions. Through connectivity with the thalamus and SMA, the cerebellum mediates error and post-error processing in accord with known anatomical projections. Taken together, these new findings highlight the role of the cerebello-thalamo-cortical pathway in an executive function that has heretofore largely been ascribed to the anterior cingulate-prefrontal cortical circuit. Copyright © 2010 Elsevier Inc. All rights reserved.

Rotational Energy Transfer of N2 Gas Determined Using a New Ab Initio Potential Energy Surface

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

1997-01-01

Rotational energy transfer between two N2 molecules is a fundamental process of some importance. Exchange is expected to play a role, but its importance is somewhat uncertain. Rotational energy transfer cross sections of N2 also have applications in many other fields including modeling of aerodynamic flows, laser operations, and linewidth analysis in nonintrusive laser diagnostics. A number of N2-N2 rigid rotor potential energy surface (PES) has been reported in the literature.

Inland occurrence of the strand plant Ipomeoa pes-caprae (Convolvulaceae) around Lake Nicaragua

Treesearch

Margaret S. Devall; Leonard B. Thien

2005-01-01

Ipomoea pes-caprae (L.) Roth (railroad vine, Convolvulaceae) is a pantropical, perenial beach plant that forms large patches just above the high tide line on coastal beaches and dunes throughout tropical and subtropical areas of the world. In spite of its wide distribution, only rare occurrences of I. pes-caprae have been...

[Job retention and nursing practice environment of hospital nurses in Japan applying the Japanese version of the Practice Environment Scale of the Nursing Work Index (PES-NWI)].

PubMed

Ogata, Yasuko; Nagano, Midori; Fukuda, Takashi; Hashimoto, Michio

2011-06-01

The purpose of this study was to examine how the nursing practice environment affects job retention and the turnover rate among hospital nurses. The Practice Environment Scale of the Nursing Work Index (PES-NWI) was applied to investigate the nurse working environment from the viewpoint of hospital nurses in Japan. Methods A postal mail survey was conducted using the PES-NWI questionnaire targeting 2,211 nurses who were working at 91 wards in 5 hospitals situated in the Tokyo metropolitan area from February to March in 2008. In the questionnaire, hospital nurses were asked about characteristics such as sex, age and work experience as a nurse, whether they would work at the same hospital in the next year, the 31 items of the PES-NWI and job satisfaction. Nurse managers were asked to provide staff numbers to calculate the turnover rate of each ward. Logistic regression analyses were carried out, with "intention to retain or leave the workplace next year" as the dependent variable, with composite and 5 sub-scale scores of the PES-NWI and nurse characteristics as independent variables. Correlation coefficients were calculated to investigate the relationship between nurse turnover rates and nursing practice environments. A total of 1,067 full-time nurses (48.3%) from 5 hospitals responded. Almost all of them were men (95.9%), with an average age of 29.2 years old. They had an average of 7.0 years total work experience in hospitals and 5.8 years of experience at their current hospital. Cronbach's alpha coefficients were 0.75 for composite of the PES-NWI, and 0.77-0.85 for the sub-scales. All correlation coefficients between PES-NWI and job satisfaction were significant (P < 0.01). In the logistic regression analysis, a composite of PES-NWI, "Nurse Manager's Ability, Leadership, and Support of Nurses" and "Staffing and Resource Adequacy" among the 5 sub-scales correlated with the intention of nurses to stay on (P < 0.05). The means for turnover rate were 10.4% for nurses and 17.6% for newly hired nurses. These rates were significantly correlated to the composite and some sub-scales of the PES-NWI. The working environment for nurses is important in retaining nurses working at hospitals. We confirmed the reliability and the validity of the PES-NWI scale based on the magnitude of the Cronbach's alpha coefficient and correlation coefficient between the PES-NWI scale and job satisfaction in this study.

Five-year follow-up of the endothelial progenitor cell capturing stent versus the paxlitaxel-eluting stent in de novo coronary lesions with a high risk of coronary restenosis.

PubMed

Woudstra, Pier; Kalkman, Deborah N; Beijk, Marcel A; Klomp, Margo; Damman, Peter; Koch, Karel T; Henriques, Jose P S; Baan, Jan; Vis, Marije M; Piek, Jan J; Tijssen, Jan G P; de Winter, Robbert J

2018-06-01

To assess the long-term safety and clinical efficacy of the Genous endothelial progenitor cell capturing stent (ECS) compared with the TAXUS Liberté paclitaxel-eluting stent (PES) in lesions with a high risk of restenosis. Instead of the use of cytotoxic or cytostatic drugs in drug-eluting stents, a "pro-healing" approach in ECS may overcome impeded healing response due to delayed functional endothelialization of the stent struts. In the prospective, randomized TRIAS pilot study 193 patients with coronary artery lesions carrying a high risk of restenosis were included (ECS: n = 98, PES: n = 95). The primary focus of this analysis was target vessel failure (TVF) at 5 years. Dual antiplatelet therapy was prescribed for ≥1 month after ECS and for ≥6 months after PES. At 5 years follow-up, no significant differences were found in TVF (ECS 24% vs. PES 29%, risk difference 95% confidence interval (RDCI) -17.3% to 7.4%). Between 2 and 5 years after the index procedure, low numbers of TVF were observed in ECS compared with PES (ECS 4% vs. PES 16%, RDCI -20.8% to -2.3%). There was no definite stent thrombosis in ECS compared with four patients in the PES group. This is the first randomized study providing very long-term clinical efficacy and safety of the ECS in lesions carrying a high risk of restenosis. At 5 years follow-up, TVF rates in ECS group are numerically lower compared with PES due to an increase of events between 2 and 5 years after the index procedure. © 2017 Wiley Periodicals, Inc.

Evaluation of the Permanence of Land Use Change Induced by Payments for Environmental Services in Quindío, Colombia.

PubMed

Pagiola, Stefano; Honey-Rosés, Jordi; Freire-González, Jaume

2016-01-01

The effectiveness of conservation interventions such as Payments for Environmental Services (PES) is often evaluated--if it is evaluated at all--only at the completion of the intervention. Since gains achieved by the intervention may be lost after it ends, even apparently successful interventions may not result in long-term conservation benefits, a problem known as that of permanence. This paper uses a unique dataset to examine the permanence of land use change induced by a short-term, asset-building PES program implemented in Quindío, Colombia, between 2003 and 2008. This the first PES program to have a control group for comparison. Under this program, PES had been found to have a positive and highly significant impact on land use. To assess the long-term permanence of these changes, both PES recipients and control households were re-surveyed in 2011, four years after the last payment was made. We find that the land use changes that had been induced by PES were broadly sustained in intervening years, with minor differences across specific practices and sub-groups of participants, indicating that these changes were in fact permanent. The patterns of change in the period after the PES program was completed also help better understand the reasons for the program's success. These results suggest that, at least in the case of productive land uses such as silvopastoral practices under conditions such as those at the study site, asset-building PES programs can be effective at encouraging land owners to adopt environmentally-beneficial land management practices and that the benefits will persist after payments cease.

Post-error action control is neurobehaviorally modulated under conditions of constant speeded response.

PubMed

Soshi, Takahiro; Ando, Kumiko; Noda, Takamasa; Nakazawa, Kanako; Tsumura, Hideki; Okada, Takayuki

2014-01-01

Post-error slowing (PES) is an error recovery strategy that contributes to action control, and occurs after errors in order to prevent future behavioral flaws. Error recovery often malfunctions in clinical populations, but the relationship between behavioral traits and recovery from error is unclear in healthy populations. The present study investigated the relationship between impulsivity and error recovery by simulating a speeded response situation using a Go/No-go paradigm that forced the participants to constantly make accelerated responses prior to stimuli disappearance (stimulus duration: 250 ms). Neural correlates of post-error processing were examined using event-related potentials (ERPs). Impulsivity traits were measured with self-report questionnaires (BIS-11, BIS/BAS). Behavioral results demonstrated that the commission error for No-go trials was 15%, but PES did not take place immediately. Delayed PES was negatively correlated with error rates and impulsivity traits, showing that response slowing was associated with reduced error rates and changed with impulsivity. Response-locked error ERPs were clearly observed for the error trials. Contrary to previous studies, error ERPs were not significantly related to PES. Stimulus-locked N2 was negatively correlated with PES and positively correlated with impulsivity traits at the second post-error Go trial: larger N2 activity was associated with greater PES and less impulsivity. In summary, under constant speeded conditions, error monitoring was dissociated from post-error action control, and PES did not occur quickly. Furthermore, PES and its neural correlate (N2) were modulated by impulsivity traits. These findings suggest that there may be clinical and practical efficacy of maintaining cognitive control of actions during error recovery under common daily environments that frequently evoke impulsive behaviors.

Post-error action control is neurobehaviorally modulated under conditions of constant speeded response

PubMed Central

Soshi, Takahiro; Ando, Kumiko; Noda, Takamasa; Nakazawa, Kanako; Tsumura, Hideki; Okada, Takayuki

2015-01-01

Post-error slowing (PES) is an error recovery strategy that contributes to action control, and occurs after errors in order to prevent future behavioral flaws. Error recovery often malfunctions in clinical populations, but the relationship between behavioral traits and recovery from error is unclear in healthy populations. The present study investigated the relationship between impulsivity and error recovery by simulating a speeded response situation using a Go/No-go paradigm that forced the participants to constantly make accelerated responses prior to stimuli disappearance (stimulus duration: 250 ms). Neural correlates of post-error processing were examined using event-related potentials (ERPs). Impulsivity traits were measured with self-report questionnaires (BIS-11, BIS/BAS). Behavioral results demonstrated that the commission error for No-go trials was 15%, but PES did not take place immediately. Delayed PES was negatively correlated with error rates and impulsivity traits, showing that response slowing was associated with reduced error rates and changed with impulsivity. Response-locked error ERPs were clearly observed for the error trials. Contrary to previous studies, error ERPs were not significantly related to PES. Stimulus-locked N2 was negatively correlated with PES and positively correlated with impulsivity traits at the second post-error Go trial: larger N2 activity was associated with greater PES and less impulsivity. In summary, under constant speeded conditions, error monitoring was dissociated from post-error action control, and PES did not occur quickly. Furthermore, PES and its neural correlate (N2) were modulated by impulsivity traits. These findings suggest that there may be clinical and practical efficacy of maintaining cognitive control of actions during error recovery under common daily environments that frequently evoke impulsive behaviors. PMID:25674058

Psychotic experiences and general medical conditions: a cross-national analysis based on 28 002 respondents from 16 countries in the WHO World Mental Health Surveys.

PubMed

Scott, Kate M; Saha, Sukanta; Lim, Carmen C W; Aguilar-Gaxiola, Sergio; Al-Hamzawi, Ali; Alonso, Jordi; Benjet, Corina; Bromet, Evelyn J; Bruffaerts, Ronny; Caldas-de-Almeida, José Miguel; de Girolamo, Giovanni; de Jonge, Peter; Degenhardt, Louisa; Florescu, Silvia; Gureje, Oye; Haro, Josep M; Hu, Chiyi; Karam, Elie G; Kovess-Masfety, Viviane; Lee, Sing; Lepine, Jean-Pierre; Mneimneh, Zeina; Navarro-Mateu, Fernando; Piazza, Marina; Posada-Villa, José; Sampson, Nancy A; Stagnaro, Juan Carlos; Kessler, Ronald C; McGrath, John J

2018-02-26

Previous work has identified associations between psychotic experiences (PEs) and general medical conditions (GMCs), but their temporal direction remains unclear as does the extent to which they are independent of comorbid mental disorders. In total, 28 002 adults in 16 countries from the WHO World Mental Health (WMH) Surveys were assessed for PEs, GMCs and 21 Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) mental disorders. Discrete-time survival analyses were used to estimate the associations between PEs and GMCs with various adjustments. After adjustment for comorbid mental disorders, temporally prior PEs were significantly associated with subsequent onset of 8/12 GMCs (arthritis, back or neck pain, frequent or severe headache, other chronic pain, heart disease, high blood pressure, diabetes and peptic ulcer) with odds ratios (ORs) ranging from 1.3 [95% confidence interval (CI) 1.1-1.5] to 1.9 (95% CI 1.4-2.4). In contrast, only three GMCs (frequent or severe headache, other chronic pain and asthma) were significantly associated with subsequent onset of PEs after adjustment for comorbid GMCs and mental disorders, with ORs ranging from 1.5 (95% CI 1.2-1.9) to 1.7 (95% CI 1.2-2.4). PEs were associated with the subsequent onset of a wide range of GMCs, independent of comorbid mental disorders. There were also associations between some medical conditions (particularly those involving chronic pain) and subsequent PEs. Although these findings will need to be confirmed in prospective studies, clinicians should be aware that psychotic symptoms may be risk markers for a wide range of adverse health outcomes. Whether PEs are causal risk factors will require further research.

Inhibitory Mechanisms in Primary Somatosensory Cortex Mediate the Effects of Peripheral Electrical Stimulation on Tactile Spatial Discrimination.

PubMed

Saito, Kei; Otsuru, Naofumi; Inukai, Yasuto; Kojima, Sho; Miyaguchi, Shota; Tsuiki, Shota; Sasaki, Ryoki; Onishi, Hideaki

2018-06-01

Selective afferent activation can be used to improve somatosensory function, possibly by altering cortical inhibitory circuit activity. Peripheral electrical stimulation (PES) is widely used to induce selective afferent activation, and its effect may depend on PES intensity. Therefore, we investigated the effects of high- and low-intensity PES applied to the right index finger on tactile discrimination performance and cortical sensory-evoked potential paired-pulse depression (SEP-PPD) in 25 neurologically healthy subjects. In Experiment 1, a grating orientation task (GOT) was performed before and immediately after local high- and low-intensity PES (both delivered as 1-s, 20-Hz trains of 0.2-ms electrical pulses at 5-s intervals). In Experiment 2, PPD of SEP components N20/P25_SEP-PPD and N20_SEP-PPD, respectively, were assessed before and immediately after high- and low-intensity PES. Improved GOT discrimination performance after high-intensity PES (reduced discrimination threshold) was associated with lower baseline performance (higher baseline discrimination threshold). Subjects were classified into low and high (baseline) GOT performance groups. Improved GOT discrimination performance in the low GOT performance group was significantly associated with a greater N20_SEP-PPD decrease (weaker PPD). Subjects were also classified into GOT improvement and GOT decrement groups. High-intensity PES decreased N20_SEP-PPD in the GOT improvement group but increased N20_SEP-PPD in the GOT decrement group. Furthermore, a greater decrease in GOT discrimination threshold was significantly associated with a greater N20_SEP-PPD decrease in the GOT improvement group. These results suggest that high-intensity PES can improve sensory perception in subjects with low baseline function by modulating cortical inhibitory circuits in primary somatosensory cortex. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Binding energies from diffusion Monte Carlo for the MB-pol H{sub 2}O and D{sub 2}O dimer: A comparison to experimental values

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mallory, Joel D.; Mandelshtam, Vladimir A.

2015-10-14

The diffusion Monte Carlo (DMC) method is applied to compute the ground state energies of the water monomer and dimer and their D{sub 2}O isotopomers using MB-pol; the most recent and most accurate ab inito-based potential energy surface (PES). MB-pol has already demonstrated excellent agreement with high level electronic structure data, as well as agreement with some experimental, spectroscopic, and thermodynamic data. Here, the DMC binding energies of (H{sub 2}O){sub 2} and (D{sub 2}O){sub 2} agree with the corresponding values obtained from velocity map imaging within, respectively, 0.01 and 0.02 kcal/mol. This work adds two more valuable data points thatmore » highlight the accuracy of the MB-pol PES.« less

Precise Design of Phosphorescent Molecular Butterflies with Tunable Photoinduced Structural Change and Dual Emission.

PubMed

Zhou, Chenkun; Tian, Yu; Yuan, Zhao; Han, Mingu; Wang, Jamie; Zhu, Lei; Tameh, Maliheh Shaban; Huang, Chen; Ma, Biwu

2015-08-10

Photoinduced structural change (PSC) is a fundamental excited-state dynamic process in chemical and biological systems. However, precise control of PSC processes is very challenging, owing to the lack of guidelines for designing excited-state potential energy surfaces (PESs). A series of rationally designed butterfly-like phosphorescent binuclear platinum complexes that undergo controlled PSC by Pt-Pt distance shortening and exhibit tunable dual (greenish-blue and red) emission are herein reported. Based on the Bell-Evans-Polanyi principle, it is demonstrated how the energy barrier of the PSC, which can be described as a chemical-reaction-like process between the two energy minima on the first triplet excited-state PES, can be controlled by synthetic means. These results reveal a simple method to engineer the dual emission of molecular systems by manipulating PES to control PSC. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Observation of H displacement and H2 elimination channels in the reaction of O(3P) with 1-butene from crossed beams and theoretical studies

NASA Astrophysics Data System (ADS)

Caracciolo, Adriana; Vanuzzo, Gianmarco; Balucani, Nadia; Stranges, Domenico; Cavallotti, Carlo; Casavecchia, Piergiorgio

2017-09-01

We report preliminary combined experimental/theoretical results on O(3P) + 1-butene reaction dynamics with focus on atomic hydrogen displacement and molecular hydrogen elimination channels. Dynamics and relative yield of the ethylvinoxy + H and ethylketene + H2 product channels are characterized in crossed beam experiments. Stationary points and energetics of triplet/singlet C4H8O potential energy surfaces (PESs) are calculated at CCSD(T)/CBS and CASPT2 level. O(3P) attack occurs on both unsaturated C-atoms with preference for the less substituted one leading, among other products, to C2H5CHCHO + H via an exit barrier on the triplet PES, and to C2H5CHCO + H2 via a very high exit barrier on the singlet PES following intersystem crossing.

Fission fragment mass and total kinetic energy distributions of spontaneously fissioning plutonium isotopes

NASA Astrophysics Data System (ADS)

Pomorski, K.; Nerlo-Pomorska, B.; Bartel, J.; Schmitt, C.

2018-03-01

The fission-fragment mass and total kinetic energy (TKE) distributions are evaluated in a quantum mechanical framework using elongation, mass asymmetry, neck degree of freedom as the relevant collective parameters in the Fourier shape parametrization recently developed by us. The potential energy surfaces (PES) are calculated within the macroscopic-microscopic model based on the Lublin-Strasbourg Drop (LSD), the Yukawa-folded (YF) single-particle potential and a monopole pairing force. The PES are presented and analysed in detail for even-even Plutonium isotopes with A = 236-246. They reveal deep asymmetric valleys. The fission-fragment mass and TKE distributions are obtained from the ground state of a collective Hamiltonian computed within the Born-Oppenheimer approximation, in the WKB approach by introducing a neck-dependent fission probability. The calculated mass and total kinetic energy distributions are found in good agreement with the data.

Accurate transport properties for H–CO and H–CO{sub 2}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dagdigian, Paul J., E-mail: pjdagdigian@jhu.edu

2015-08-07

Transport properties for collisions of hydrogen atoms with CO and CO{sub 2} have been computed by means of quantum scattering calculations. The carbon oxides are important species in hydrocarbon combustion. The following potential energy surfaces (PES’s) for the interaction of the molecule fixed in its equilibrium geometry were employed: for H–CO, the PES was taken from the work of Song et al. [J. Phys. Chem. A 117, 7571 (2013)], while the PES for H–CO{sub 2} was computed in this study by a restricted coupled cluster method that included single, double, and (perturbatively) triple excitations. The computed transport properties were foundmore » to be significantly different from those computed by the conventional approach that employs isotropic Lennard-Jones (12-6) potentials. The effect of using the presently computed accurate transport properties in 1-dimensional combustion simulations of methane-air flames was investigated.« less

DFT studies on the multi-channel reaction of CH3S+NO2

NASA Astrophysics Data System (ADS)

Tang, Yi-Zhen; Sun, Hao; Pan, Ya-Ru; Pan, Xiu-Mei; Wang, Rong-Shun

The mechanisms for the reaction of CH3S with NO2 are investigated at the QCISD(T)/6-311++G(d,p)//B3LYP/6-311++G(d,p) on both single and triple potential energy surfaces (PESs). The geometries, vibrational frequencies, and zero-point energy (ZPE) correction of all stationary points involved in the title reaction are calculated at the B3LYP/6-311++G(d,p) level. More accurate energies are obtained at the QCISD(T)/6-311++G(d,p). The results show that 5 intermediates and 14 transition states are found. The reaction is more predominant on the single PES, while it is negligible on the triple PES. Without any barrier height for the whole process, the main channel of the reaction is to form CH3SONO and then dissociate to CH3SO+NO.

Diagonal Born-Oppenheimer correction for coupled-cluster wave-functions

NASA Astrophysics Data System (ADS)

Shamasundar, K. R.

2018-06-01

We examine how geometry-dependent normalisation freedom of electronic wave-functions affects extraction of a meaningful diagonal Born-Oppenheimer correction (DBOC) to the ground-state Born-Oppenheimer potential energy surface (PES). By viewing this freedom as a kind of gauge-freedom, it is shown that DBOC and the resulting associated mass-dependent adiabatic PES are gauge-invariant quantities. A sum-over-states (SOS) formula for DBOC which explicitly exhibits this invariance is derived. A biorthogonal formulation suitable for DBOC computations using standard unnormalised coupled-cluster (CC) wave-functions is presented. This is shown to lead to a biorthogonal version of SOS formula with similar properties. On this basis, different computational schemes for evaluating DBOC using approximate CC wave-functions are derived. One of this agrees with the formula used in the current literature. The connection to adiabatic-to-diabatic transformations in non-adiabatic dynamics is explored and complications arising from biorthogonal nature of CC theory are identified.

Diabetic and nondiabetic patients with left main and/or 3-vessel coronary artery disease: comparison of outcomes with cardiac surgery and paclitaxel-eluting stents.

PubMed

Banning, Adrian P; Westaby, Stephen; Morice, Marie-Claude; Kappetein, A Pieter; Mohr, Friedrich W; Berti, Sergio; Glauber, Mattia; Kellett, Mirle A; Kramer, Robert S; Leadley, Katrin; Dawkins, Keith D; Serruys, Patrick W

2010-03-16

This study was designed to compare contemporary surgical revascularization (coronary artery bypass graft surgery [CABG]) versus TAXUS Express (Boston Scientific, Natick, Massachusetts) paclitaxel-eluting stents (PES) in diabetic and nondiabetic patients with left main and/or 3-vessel disease. Although the prevalence of diabetes mellitus is increasing, the optimal coronary revascularization strategy in diabetic patients with complex multivessel disease remains controversial. The SYNTAX (SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery) study randomly assigned 1,800 patients (452 with medically treated diabetes) to receive PES or CABG. The overall 1-year major adverse cardiac and cerebrovascular event rate was higher among diabetic patients treated with PES compared with CABG, but the revascularization method did not impact the death/stroke/myocardial infarction rate for nondiabetic patients (6.8% CABG vs. 6.8% PES, p = 0.97) or for diabetic patients (10.3% CABG vs. 10.1% PES, p = 0.96). The presence of diabetes was associated with significantly increased mortality after either revascularization treatment. The incidence of stroke was higher among nondiabetic patients after CABG (2.2% vs. PES 0.5%, p = 0.006). Compared with CABG, mortality was higher after PES use for diabetic patients with highly complex lesions (4.1% vs. 13.5%, p = 0.04). Revascularization with PES resulted in higher repeat revascularization for nondiabetic patients (5.7% vs. 11.1%, p < 0.001) and diabetic patients (6.4% vs. 20.3%, p < 0.001). Subgroup analyses suggest that the 1-year major adverse cardiac and cerebrovascular event rate is higher among diabetic patients with left main and/or 3-vessel disease treated with PES compared with CABG, driven by an increase in repeat revascularization. However, the composite safety end point (death/stroke/myocardial infarction) is comparable between the 2 treatment options for diabetic and nondiabetic patients. Although further study is needed, these exploratory results may extend the evidence for PES use in selected patients with less complex left main and/or 3-vessel lesions. (SYNergy Between PCI With TAXus and Cardiac Surgery [SYNTAX]; NCT00114972). Copyright 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

The associations between psychotic experiences and substance use and substance use disorders: findings from the World Health Organization World Mental Health surveys.

PubMed

Degenhardt, Louisa; Saha, Sukanta; Lim, Carmen C W; Aguilar-Gaxiola, Sergio; Al-Hamzawi, Ali; Alonso, Jordi; Andrade, Laura H; Bromet, Evelyn J; Bruffaerts, Ronny; Caldas-de-Almeida, José Miguel; de Girolamo, Giovanni; Florescu, Silvia; Gureje, Oye; Haro, Josep M; Karam, Elie G; Karam, Georges; Kovess-Masfety, Viviane; Lee, Sing; Lepine, Jean-Pierre; Makanjuola, Victor; Medina-Mora, Maria E; Mneimneh, Zeina; Navarro-Mateu, Fernando; Piazza, Marina; Posada-Villa, José; Sampson, Nancy A; Scott, Kate M; Stagnaro, Juan Carlos; Ten Have, Margreet; Kendler, Kenneth S; Kessler, Ronald C; McGrath, John J

2018-05-01

Prior research has found bidirectional associations between psychotic experiences (PEs) and selected substance use disorders. We aimed to extend this research by examining the bidirectional association between PEs and various types of substance use (SU) and substance use disorders (SUDs), and the influence of antecedent mental disorders on these associations. We used data from the World Health Organization World Mental Health surveys. A total of 30 902 adult respondents across 18 countries were assessed for (a) six types of life-time PEs, (b) a range of types of SU and DSM-IV SUDs and (c) mental disorders using the Composite International Diagnostic Interview. Discrete-time survival analyses based on retrospective age-at-onset reports examined the bidirectional associations between PEs and SU/SUDs controlling for antecedent mental disorders. After adjusting for demographics, comorbid SU/SUDs and antecedent mental disorders, those with prior alcohol use disorders [odds ratio (OR) = 1.6, 95% confidence interval (CI) = 1.2-2.0], extra-medical prescription drug use (OR = 1.5, 95% CI = 1.1-1.9), alcohol use (OR = 1.4, 95% CI = 1.1-1.7) and tobacco use (OR = 1.3, 95% CI = 1.0-1.8) had increased odds of subsequent first onset of PEs. In contrast, those with temporally prior PEs had increased odds of subsequent onset of tobacco use (OR = 1.5, 95% CI = 1.2-1.9), alcohol use (OR = 1.3, 95% CI = 1.1-1.6) or cannabis use (OR = 1.3, 95% CI = 1.0-1.5) as well as of all substance use disorders (ORs ranged between 1.4 and 1.5). There was a dose response relationship between both count and frequency of PEs and increased subsequent odds of selected SU/SUDs. Associations between psychotic experiences (PEs) and substance use/substance use disorders (SU/SUDs) are often bidirectional, but not all types of SU/SUDs are associated with PEs. These findings suggest that it is important to be aware of the presence of PEs within those with SUDs or at risk of SUDs, given the plausibility that they may each impact upon the other. © 2017 Society for the Study of Addiction.

Interdependence of Pes1, Bop1, and WDR12 controls nucleolar localization and assembly of the PeBoW complex required for maturation of the 60S ribosomal subunit.

PubMed

Rohrmoser, Michaela; Hölzel, Michael; Grimm, Thomas; Malamoussi, Anastassia; Harasim, Thomas; Orban, Mathias; Pfisterer, Iris; Gruber-Eber, Anita; Kremmer, Elisabeth; Eick, Dirk

2007-05-01

The PeBoW complex is essential for cell proliferation and maturation of the large ribosomal subunit in mammalian cells. Here we examined the role of PeBoW-specific proteins Pes1, Bop1, and WDR12 in complex assembly and stability, nucleolar transport, and pre-ribosome association. Recombinant expression of the three subunits is sufficient for complex formation. The stability of all three subunits strongly increases upon incorporation into the complex. Only overexpression of Bop1 inhibits cell proliferation and rRNA processing, and its negative effects could be rescued by coexpression of WDR12, but not Pes1. Elevated levels of Bop1 induce Bop1/WDR12 and Bop1/Pes1 subcomplexes. Knockdown of Bop1 abolishes the copurification of Pes1 with WDR12, demonstrating Bop1 as the integral component of the complex. Overexpressed Bop1 substitutes for endogenous Bop1 in PeBoW complex assembly, leading to the instability of endogenous Bop1. Finally, indirect immunofluorescence, cell fractionation, and sucrose gradient centrifugation experiments indicate that transport of Bop1 from the cytoplasm to the nucleolus is Pes1 dependent, while Pes1 can migrate to the nucleolus and bind to preribosomal particles independently of Bop1. We conclude that the assembly and integrity of the PeBoW complex are highly sensitive to changes in Bop1 protein levels.

Spectroscopy of H3+ based on a new high-accuracy global potential energy surface.

PubMed

Polyansky, Oleg L; Alijah, Alexander; Zobov, Nikolai F; Mizus, Irina I; Ovsyannikov, Roman I; Tennyson, Jonathan; Lodi, Lorenzo; Szidarovszky, Tamás; Császár, Attila G

2012-11-13

The molecular ion H(3)(+) is the simplest polyatomic and poly-electronic molecular system, and its spectrum constitutes an important benchmark for which precise answers can be obtained ab initio from the equations of quantum mechanics. Significant progress in the computation of the ro-vibrational spectrum of H(3)(+) is discussed. A new, global potential energy surface (PES) based on ab initio points computed with an average accuracy of 0.01 cm(-1) relative to the non-relativistic limit has recently been constructed. An analytical representation of these points is provided, exhibiting a standard deviation of 0.097 cm(-1). Problems with earlier fits are discussed. The new PES is used for the computation of transition frequencies. Recently measured lines at visible wavelengths combined with previously determined infrared ro-vibrational data show that an accuracy of the order of 0.1 cm(-1) is achieved by these computations. In order to achieve this degree of accuracy, relativistic, adiabatic and non-adiabatic effects must be properly accounted for. The accuracy of these calculations facilitates the reassignment of some measured lines, further reducing the standard deviation between experiment and theory.

Progress in calculating the potential energy surface of H3+.

PubMed

Adamowicz, Ludwik; Pavanello, Michele

2012-11-13

The most accurate electronic structure calculations are performed using wave function expansions in terms of basis functions explicitly dependent on the inter-electron distances. In our recent work, we use such basis functions to calculate a highly accurate potential energy surface (PES) for the H(3)(+) ion. The functions are explicitly correlated Gaussians, which include inter-electron distances in the exponent. Key to obtaining the high accuracy in the calculations has been the use of the analytical energy gradient determined with respect to the Gaussian exponential parameters in the minimization of the Rayleigh-Ritz variational energy functional. The effective elimination of linear dependences between the basis functions and the automatic adjustment of the positions of the Gaussian centres to the changing molecular geometry of the system are the keys to the success of the computational procedure. After adiabatic and relativistic corrections are added to the PES and with an effective accounting of the non-adiabatic effects in the calculation of the rotational/vibrational states, the experimental H(3)(+) rovibrational spectrum is reproduced at the 0.1 cm(-1) accuracy level up to 16,600 cm(-1) above the ground state.

Potential Energy Surface-Based Automatic Deduction of Conformational Transition Networks and Its Application on Quantum Mechanical Landscapes of d-Glucose Conformers.

PubMed

Satoh, Hiroko; Oda, Tomohiro; Nakakoji, Kumiyo; Uno, Takeaki; Tanaka, Hiroaki; Iwata, Satoru; Ohno, Koichi

2016-11-08

This paper describes our approach that is built upon the potential energy surface (PES)-based conformational analysis. This approach automatically deduces a conformational transition network, called a conformational reaction route map (r-map), by using the Scaled Hypersphere Search of the Anharmonic Downward Distortion Following method (SHS-ADDF). The PES-based conformational search has been achieved by using large ADDF, which makes it possible to trace only low transition state (TS) barriers while restraining bond lengths and structures with high free energy. It automatically performs sampling the minima and TS structures by simply taking into account the mathematical feature of PES without requiring any a priori specification of variable internal coordinates. An obtained r-map is composed of equilibrium (EQ) conformers connected by reaction routes via TS conformers, where all of the reaction routes are already confirmed during the process of the deduction using the intrinsic reaction coordinate (IRC) method. The postcalculation analysis of the deduced r-map is interactively carried out using the RMapViewer software we have developed. This paper presents computational details of the PES-based conformational analysis and its application to d-glucose. The calculations have been performed for an isolated glucose molecule in the gas phase at the RHF/6-31G level. The obtained conformational r-map for α-d-glucose is composed of 201 EQ and 435 TS conformers and that for β-d-glucose is composed of 202 EQ and 371 TS conformers. For the postcalculation analysis of the conformational r-maps by using the RMapViewer software program we have found multiple minimum energy paths (MEPs) between global minima of 1 C 4 and 4 C 1 chair conformations. The analysis using RMapViewer allows us to confirm the thermodynamic and kinetic predominance of 4 C 1 conformations; that is, the potential energy of the global minimum of 4 C 1 is lower than that of 1 C 4 (thermodynamic predominance) and that the highest energy of those of all the TS structures along a route from 4 C 1 to 1 C 4 is lower than that of 1 C 4 to 4 C 1 (kinetic predominance).

Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction

NASA Astrophysics Data System (ADS)

Jambrina, P. G.; Lara, Manuel; Menéndez, M.; Launay, J.-M.; Aoiz, F. J.

2012-10-01

Cumulative reaction probabilities (CRPs) at various total angular momenta have been calculated for the barrierless reaction S(1D) + H2 → SH + H at total energies up to 1.2 eV using three different theoretical approaches: time-independent quantum mechanics (QM), quasiclassical trajectories (QCT), and statistical quasiclassical trajectories (SQCT). The calculations have been carried out on the widely used potential energy surface (PES) by Ho et al. [J. Chem. Phys. 116, 4124 (2002), 10.1063/1.1431280] as well as on the recent PES developed by Song et al. [J. Phys. Chem. A 113, 9213 (2009), 10.1021/jp903790h]. The results show that the differences between these two PES are relatively minor and mostly related to the different topologies of the well. In addition, the agreement between the three theoretical methodologies is good, even for the highest total angular momenta and energies. In particular, the good accordance between the CRPs obtained with dynamical methods (QM and QCT) and the statistical model (SQCT) indicates that the reaction can be considered statistical in the whole range of energies in contrast with the findings for other prototypical barrierless reactions. In addition, total CRPs and rate coefficients in the range of 20-1000 K have been calculated using the QCT and SQCT methods and have been found somewhat smaller than the experimental total removal rates of S(1D).

Location of protons in N-H···N hydrogen-bonded systems: a theoretical study on intramolecular pyridine-dihydropyridine and pyridine-pyridinium pairs.

PubMed

Mori, Yukie; Takano, Keiko

2012-08-21

Two-dimensional potential energy surfaces (PESs) were calculated for the degenerate intramolecular proton transfer (PT) in two N-H···N hydrogen-bonded systems, (Z)-2-(2-pyridylmethylidene)-1,2-dihydropyridine (1) and monoprotonated di(2-pyridyl) ether (2), at the MP2/cc-pVDZ level of theory. The calculated PES had two minima in both cases. The energy barrier in 1 was higher than the zero-point energy (ZPE) level, while that in 2 was close to the ZPE. Vibrational wavefunctions were obtained by solving time-independent Schrödinger equations with the calculated PESs. The maximum points of the probability density were shifted from the energy minima towards the region where the covalent N-H bond was elongated and the N···N distance shortened. The effects of a polar solvent on the PES were investigated with the continuum or cluster models in such a way that the solute-solvent electrostatic interactions could be taken into account under non-equilibrated conditions. A solvated contact ion-pair was modelled by a cluster consisting of one cation 2, one chloride ion and 26 molecules of acetonitrile. The calculation with this model suggested that the bridging proton is localised in the deeper well due to the significant asymmetry of the PES and the high potential barrier.

H4: A challenging system for natural orbital functional approximations

NASA Astrophysics Data System (ADS)

Ramos-Cordoba, Eloy; Lopez, Xabier; Piris, Mario; Matito, Eduard

2015-10-01

The correct description of nondynamic correlation by electronic structure methods not belonging to the multireference family is a challenging issue. The transition of D2h to D4h symmetry in H4 molecule is among the most simple archetypal examples to illustrate the consequences of missing nondynamic correlation effects. The resurgence of interest in density matrix functional methods has brought several new methods including the family of Piris Natural Orbital Functionals (PNOF). In this work, we compare PNOF5 and PNOF6, which include nondynamic electron correlation effects to some extent, with other standard ab initio methods in the H4 D4h/D2h potential energy surface (PES). Thus far, the wrongful behavior of single-reference methods at the D2h-D4h transition of H4 has been attributed to wrong account of nondynamic correlation effects, whereas in geminal-based approaches, it has been assigned to a wrong coupling of spins and the localized nature of the orbitals. We will show that actually interpair nondynamic correlation is the key to a cusp-free qualitatively correct description of H4 PES. By introducing interpair nondynamic correlation, PNOF6 is shown to avoid cusps and provide the correct smooth PES features at distances close to the equilibrium, total and local spin properties along with the correct electron delocalization, as reflected by natural orbitals and multicenter delocalization indices.

Nucleophilic Substitution in Solution: Activation Strain Analysis of Weak and Strong Solvent Effects

PubMed Central

Hamlin, Trevor A.; van Beek, Bas; Wolters, Lando P.

2018-01-01

Abstract We have quantum chemically studied the effect of various polar and apolar solvents on the shape of the potential energy surface (PES) of a diverse collection of archetypal nucleophilic substitution reactions at carbon, silicon, phosphorus, and arsenic by using density functional theory at the OLYP/TZ2P level. In the gas phase, all our model SN2 reactions have single‐well PESs, except for the nucleophilic substitution reaction at carbon (SN2@C), which has a double‐well energy profile. The presence of the solvent can have a significant effect on the shape of the PES and, thus, on the nature of the SN2 process. Solvation energies, charges on the nucleophile or leaving group, and structural features are compared for the various SN2 reactions in a spectrum of solvents. We demonstrate how solvation can change the shape of the PES, depending not only on the polarity of the solvent, but also on how the charge is distributed over the interacting molecular moieties during different stages of the reaction. In the case of a nucleophilic substitution at three‐coordinate phosphorus, the reaction can be made to proceed through a single‐well [no transition state (TS)], bimodal barrier (two TSs), and then through a unimodal transition state (one TS) simply by increasing the polarity of the solvent. PMID:29457865

IR Spectra of (HCOOH)2 and (DCOOH)2: Experiment, VSCF/VCI, and Ab Initio Molecular Dynamics Calculations Using Full-Dimensional Potential and Dipole Moment Surfaces.

PubMed

Qu, Chen; Bowman, Joel M

2018-05-17

We report quantum VSCF/VCI and ab initio molecular dynamics (AIMD) calculations of the IR spectra of (HCOOH) 2 and (DCOOH) 2 , using full-dimensional, ab initio potential energy and dipole moment surfaces (PES and DMS). These surfaces are fits, using permutationally invariant polynomials, to 13 475 ab initio CCSD(T)-F12a electronic energies and MP2 dipole moments. Here "AIMD" means using these ab initio potential and dipole moment surfaces in the MD calculations. The VSCF/VCI calculations use all (24) normal modes for coupling, with a four-mode representation of the potential. The quantum spectra align well with jet-cooled and room-temperature experimental spectra over the spectral range 600-3600 cm -1 . Analyses of the complex O-H and C-H stretch bands are made based on the mixing of the VSCF/VCI basis functions. The comparisons of the AIMD IR spectra with both experimental and VSCF/VCI ones provide tests of the accuracy of the AIMD approach. These indicate good accuracy for simple bands but not for the complex O-H stretch band, which is upshifted from experimental and VSCF/VCI bands by roughly 300 cm -1 . In addition to testing the AIMD approach, the PES, DMS, and VSCF/VCI calculations for formic acid dimer provide opportunities for testing other methods to represent high-dimensional data and other methods that perform postharmonic vibrational calculations.

Capitation-Based Financing Hampers the Provision of Preventive Services in Primary Health Care

PubMed Central

Sándor, János; Kósa, Karolina; Papp, Magor; Fürjes, Gergő; Kőrösi, László; Jakovljevic, Mihajlo; Ádány, Róza

2016-01-01

Mortality caused by non-communicable diseases has been extremely high in Hungary, which can largely be attributed to not performed preventive examinations (PEs) at the level of primary health care (PHC). Both structures and financial incentives are lacking, which could support the provision of legally defined PEs. A Model Programme was launched in Hungary in 2012 to adapt the recommendations for PHC of the World Health Organization. A baseline survey was carried out to describe the occurrence of not performed PEs. A sample of 4320 adults representative for Hungary by age and gender was surveyed. Twelve PEs to be performed in PHC as specified by a governmental decree were investigated and quantified. Not performed PEs per person per year with 95% confidence intervals were computed for age, gender, and education strata. The number of not performed PEs for the entire adult population of Hungary was estimated and converted into expenses according to the official reimbursement costs of the National Health Insurance Fund. The rate of service use varied between 16.7 and 70.2%. There was no correlation between the unit price of examinations and service use (r = 0.356; p = 0.267). The rate of not performed PEs was not related to gender, but older age and lower education proved to be risk factors. The total number of not performed PEs was over 17 million in the country. Of the 31 million euros saved by not paying for PEs, the largest share was not spent on those in the lowest educational category. New preventive services offered in the reoriented PHC model program include systematic and scheduled health examination health promotion programs at community settings, risk assessment followed by individual or group care, and/or referral and chronic care. The Model Programme has created a pressure for collaborative work, consultation, and engagement at each level, from the GPs and health mediators up to the decision-making level. It channeled the population into preventive health services shown by the fact that more than 80% of the population in the intervention area has already participated in the health status assessment. PMID:27679797

Capitation-Based Financing Hampers the Provision of Preventive Services in Primary Health Care.

PubMed

Sándor, János; Kósa, Karolina; Papp, Magor; Fürjes, Gergő; Kőrösi, László; Jakovljevic, Mihajlo; Ádány, Róza

2016-01-01

Mortality caused by non-communicable diseases has been extremely high in Hungary, which can largely be attributed to not performed preventive examinations (PEs) at the level of primary health care (PHC). Both structures and financial incentives are lacking, which could support the provision of legally defined PEs. A Model Programme was launched in Hungary in 2012 to adapt the recommendations for PHC of the World Health Organization. A baseline survey was carried out to describe the occurrence of not performed PEs. A sample of 4320 adults representative for Hungary by age and gender was surveyed. Twelve PEs to be performed in PHC as specified by a governmental decree were investigated and quantified. Not performed PEs per person per year with 95% confidence intervals were computed for age, gender, and education strata. The number of not performed PEs for the entire adult population of Hungary was estimated and converted into expenses according to the official reimbursement costs of the National Health Insurance Fund. The rate of service use varied between 16.7 and 70.2%. There was no correlation between the unit price of examinations and service use (r = 0.356; p = 0.267). The rate of not performed PEs was not related to gender, but older age and lower education proved to be risk factors. The total number of not performed PEs was over 17 million in the country. Of the 31 million euros saved by not paying for PEs, the largest share was not spent on those in the lowest educational category. New preventive services offered in the reoriented PHC model program include systematic and scheduled health examination health promotion programs at community settings, risk assessment followed by individual or group care, and/or referral and chronic care. The Model Programme has created a pressure for collaborative work, consultation, and engagement at each level, from the GPs and health mediators up to the decision-making level. It channeled the population into preventive health services shown by the fact that more than 80% of the population in the intervention area has already participated in the health status assessment.

Avulsion fracture of an ossified pes anserinus tendon post-lateral patellar dislocation.

PubMed

Albtoush, Omar M; Taib, Abtehag A; Horger, Marius; Springer, Fabian

2018-05-01

The pes anserinus is a common tendon comprising the tendinous insertions of the sartorius, gracilis, and semitendinosus muscles. It inserts at the anteromedial aspect of the tibia and plays a significant role in stabilization of the medial side of the knee joint. The current article presents a case with recurrent lateral patellar dislocations causing chronic stress along the medial knee stabilizers and consecutive enthesophyte formation at the insertion of the pes anserinus tendon that showed a transverse fracture upon a subsequent incident of traumatic lateral patellar dislocation. Avulsion injuries of the pes anserinus tendon are rarely encountered, and to our knowledge, association with recurrent lateral patellar dislocations has not been described before.

Are litter decomposition and fire linked through plant species traits?

PubMed

Cornelissen, Johannes H C; Grootemaat, Saskia; Verheijen, Lieneke M; Cornwell, William K; van Bodegom, Peter M; van der Wal, René; Aerts, Rien

2017-11-01

Contents 653 I. 654 II. 657 III. 659 IV. 661 V. 662 VI. 663 VII. 665 665 References 665 SUMMARY: Biological decomposition and wildfire are connected carbon release pathways for dead plant material: slower litter decomposition leads to fuel accumulation. Are decomposition and surface fires also connected through plant community composition, via the species' traits? Our central concept involves two axes of trait variation related to decomposition and fire. The 'plant economics spectrum' (PES) links biochemistry traits to the litter decomposability of different fine organs. The 'size and shape spectrum' (SSS) includes litter particle size and shape and their consequent effect on fuel bed structure, ventilation and flammability. Our literature synthesis revealed that PES-driven decomposability is largely decoupled from predominantly SSS-driven surface litter flammability across species; this finding needs empirical testing in various environmental settings. Under certain conditions, carbon release will be dominated by decomposition, while under other conditions litter fuel will accumulate and fire may dominate carbon release. Ecosystem-level feedbacks between decomposition and fire, for example via litter amounts, litter decomposition stage, community-level biotic interactions and altered environment, will influence the trait-driven effects on decomposition and fire. Yet, our conceptual framework, explicitly comparing the effects of two plant trait spectra on litter decomposition vs fire, provides a promising new research direction for better understanding and predicting Earth surface carbon dynamics. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

The influence of anthropometrics on physical employment standard performance.

PubMed

Reilly, T; Spivock, M; Prayal-Brown, A; Stockbrugger, B; Blacklock, R

2016-10-01

The Canadian Armed Forces (CAF) recently implemented the Fitness for Operational Requirements of CAF Employment (FORCE), a new physical employment standard (PES). Data collection throughout development included anthropometric profiles of the CAF. To determine if anthropometric measurements and demographic information would predict the performance outcomes of the FORCE and/or Common Military Task Fitness Evaluation (CMTFE). We conducted a secondary analysis of data from FORCE research. We obtained bioelectrical impedance and segmental analysis. Statistical analysis included correlation and linear regression analyses. Among the 668 study subjects, as predicted, any task requiring lifting, pulling or moving of an object was significantly and positively correlated (r > 0.67) to lean body mass (LBM) measurements. LBM correlated with stretcher carry (r = 0.78) and with lifting actions such as sand bag drag (r = 0.77), vehicle extrication (r = 0.71), sand bag fortification (r = 0.68) and sand bag lift time (r = -0.67). The difference between the correlation of dead mass (DM) with task performance compared with LBM was not statistically significant. DM and LBM can be used in a PES to predict success on military tasks such as casualty evacuation and manual material handling. However, there is no minimum LBM required to perform these tasks successfully. These data direct future research on how we should diversify research participants by anthropometrics, in addition to the traditional demographic variables of gender and age, to highlight potential important adverse impact with PES design. In addition, the results can be used to develop better training regimens to facilitate passing a PES. © All rights reserved. ‘The Influence of Anthropometrics on Physical Employment Standard Performance’ has been reproduced with the permission of DND, 2016.

Competitive Advantage of MBA for Physician Executives: A Systematic Literature Review.

PubMed

Turner, Anthony D; Stawicki, Stanislaw P; Guo, Weidun Alan

2018-06-01

In response to systemic challenges facing the US healthcare system, many medical students, residents and practicing physicians are pursuing a Master in Business Administration (MBA) degree. The value of such proposition remains poorly defined. The aim of this review is to analyze current literature pertaining to the added value of MBA training for physician executives (PEs). We hypothesized that physicians who supplement their clinical expertise with business education gain a significant competitive advantage. A detailed literature search of four electronic databases (PubMed, SCOPUS, Embase and ERIC) was performed. Included were studies published between Jan 2000 and June 2017, focusing specifically on PEs. Among 1580 non-duplicative titles, we identified 23 relevant articles. Attributes which were found to add value to one's competitiveness as PE were recorded. A quality index score was assigned to each article in order to minimize bias. Results were tabulated by attributes and by publication. We found that competitive domains deemed to be most important for PEs in the context of MBA training were leadership (n = 17), career advancement opportunities (n = 12), understanding of financial aspects of medicine (n = 9) and team-building skills (n = 10). Among other prominent factors associated with the desire to engage in an MBA were higher compensation, awareness of public health issues/strategy, increased negotiation skills and enhanced work-life balance. Of interest, the learning of strategies for reducing malpractice litigation was less important than the other drivers. This comprehensive systemic review supports our hypothesis that a business degree confers a competitive advantage for PEs. Physician executives equipped with an MBA degree appear to be better equipped to face the challenge of the dynamically evolving healthcare landscape. This information may be beneficial to medical schools designing or implementing combined dual-degree curricula.

High-Performance Membrane Dialyzers and Mortality in Hemodialysis Patients: A 2-Year Cohort Study from the Annual Survey of the Japanese Renal Data Registry.

PubMed

Abe, Masanori; Hamano, Takayuki; Wada, Atsushi; Nakai, Shigeru; Masakane, Ikuto

2017-01-01

Little information is available regarding the type of dialyzer which results in good prognosis. This study is aimed at investigating the association between 7 types of dialyzers and 2-year mortality. We conducted a cohort study using data from a nationwide registry of the Japanese Society for Dialysis Therapy. Subjects were 136,676 patients on maintenance hemodialysis (HD) between 2009 and 2011 who underwent maintenance HD for at least 2 years and were treated with one of the following 7 types of high-performance membrane dialyzers: cellulose triacetate (CTA), ethylene vinyl alcohol (EVAL), polyacrylonitrile (PAN), polyester polymer alloy (PEPA), polyethersulfone (PES), polymethylmethacrylate (PMMA), and polysulfone (PS). Cox regression was used to estimate the association between baseline dialyzers and all-cause 2-year mortality, adjusting for potential confounders. Data were adjusted using basic factors, with PS as a reference group, and the hazard ratio (HR) was significantly higher in CTA, PMMA, PAN, and EVAL groups. Further data adjustment for Kt/V yielded the same results as were obtained from data adjusted for basic factors. After further adjustment for nutrition- and inflammation-related factors, HR was significantly lowered for the PES and PMMA groups compared with the PS group (HR 0.88; 95% CI 0.82-0.94 and HR 0.84 95% CI 0.76-0.93, respectively). After propensity score matching, HR for the PES and PMMA groups was significantly lowered compared with the PS group. The use of different membrane types may affect mortality. Further long-term prospective studies are needed to clarify whether the PES and PMMA membranes can improve prognosis. © 2017 S. Karger AG, Basel.

Assessing the effects of regional payment for watershed services program on water quality using an intervention analysis model.

PubMed

Lu, Yan; He, Tian

2014-09-15

Much attention has been recently paid to ex-post assessments of socioeconomic and environmental benefits of payment for ecosystem services (PES) programs on poverty reduction, water quality, and forest protection. To evaluate the effects of a regional PES program on water quality, we selected chemical oxygen demand (COD) and ammonia-nitrogen (NH3-N) as indicators of water quality. Statistical methods and an intervention analysis model were employed to assess whether the PES program produced substantial changes in water quality at 10 water-quality sampling stations in the Shaying River watershed, China during 2006-2011. Statistical results from paired-sample t-tests and box plots of COD and NH3-N concentrations at the 10 stations showed that the PES program has played a positive role in improving water quality and reducing trans-boundary water pollution in the Shaying River watershed. Using the intervention analysis model, we quantitatively evaluated the effects of the intervention policy, i.e., the watershed PES program, on water quality at the 10 stations. The results suggest that this method could be used to assess the environmental benefits of watershed or water-related PES programs, such as improvements in water quality, seasonal flow regulation, erosion and sedimentation, and aquatic habitat. Copyright © 2014 Elsevier B.V. All rights reserved.

Environmental service payments: evaluating biodiversity conservation trade-offs and cost-efficiency in the Osa Conservation Area, Costa Rica.

PubMed

Barton, D N; Faith, D P; Rusch, G M; Acevedo, H; Paniagua, L; Castro, M

2009-02-01

The cost-efficiency of payments for environmental services (PES) to private landowners in the Osa Conservation Area, Costa Rica, is evaluated in terms of the trade-off between biodiversity representation and opportunity costs of conservation to agricultural and forestry land-use. Using available GIS data and an 'off-the-shelf' software application called TARGET, we find that the PES allocation criteria applied by authorities in 2002-2003 were more than twice as cost-efficient as criteria applied during 1999-2001. Results show that a policy relevant assessment of the cost-effectiveness of PES relative to other conservation policies can be carried out at regional level using available studies and GIS data. However, there are a number of data and conceptual limitations to using heuristic optimisation algorithms in the analysis of the cost-efficiency of PES. Site specific data on probabilities of land-use change, and a detailed specification of opportunity costs of farm land, labour and capital are required to use algorithms such as TARGET for ranking individual sites based on cost-efficiency. Despite its conceptual soundness for regional conservation analysis, biodiversity complementarity presents a practical challenge as a criterion for PES eligibility at farm level because it varies depending on the set of areas under PES contracts at any one time.

Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene

NASA Astrophysics Data System (ADS)

Hazarika, Ankita; Deka, Biplab K.; Kim, Doyoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

2017-01-01

We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90-100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene.

Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene.

PubMed

Hazarika, Ankita; Deka, Biplab K; Kim, DoYoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

2017-01-11

We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90-100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene.

Cuff leak test and laryngeal survey for predicting post-extubation stridor.

PubMed

Patel, Anit B; Ani, Chizobam; Feeney, Colin

2015-02-01

Evidence for the predictive value of the cuff leak test (CLT) for post-extubation stridor (PES) is conflicting. We evaluated the association and accuracy of CLT alone or combined with other laryngeal parameters with PES. Fifty-one mechanically ventilated adult patients in a medical-surgical intensive care unit were tested prior to extubation using; CLT, laryngeal ultrasound and indirect laryngoscopy. Biometric, laryngeal and endotracheal tube (ETT) parameters were recorded. PES incidence was 4%. CLT demonstrated 'no leak' in 20% of patients. Laryngeal oedema was present in 10% of the patients on indirect laryngoscopy, and 71% of the patients had a Grades 1-3 indirect laryngoscopic view. Mean air column width on laryngeal ultrasound was 0.66 ± 0.15 cm (cuff deflated), mean ratio of ETT to laryngeal diameter was 0.48 ± 0.07, and the calculated CLT and laryngeal survey composite was 0.86 ± 1.25 (range 0-5). CLT and the CLT and Laryngeal survey composite measure were not associated with or predict PES. Age, sex, peri-extubation steroid use, intubation duration and body mass index were not associated with PES. Even including ultrasonographic and indirect laryngoscopic examination of the airway, no single aspect of the CLT or combination with laryngeal parameters accurately predicts PES.

Co-occurrence of psychotic experiences and common mental health conditions across four racially and ethnically diverse population samples.

PubMed

DeVylder, J E; Burnette, D; Yang, L H

2014-12-01

Prior research with racially/ethnically homogeneous samples has demonstrated widespread co-occurrence of psychotic experiences (PEs) and common mental health conditions, particularly multi-morbidity, suggesting that psychosis may be related to the overall severity of psychiatric disorder rather than any specific subtype. In this study we aimed to examine whether PEs are associated with the presence of specific disorders or multi-morbidity of co-occurring disorders across four large racially/ethnically diverse samples of adults in the USA. Data were drawn from the National Comorbidity Survey Replication (NCS-R), the National Survey of American Life (NSAL) and separately from the Asian and Latino subsamples of the National Latino and Asian American Study (NLAAS). Logistic regression models were used to examine the relationship between PEs and individual subtypes of DSM-IV disorder, and to test for a linear dose-response relationship between the number of subtypes and PEs. Prevalence of PEs was moderately greater among individuals with each subtype of disorder in each data set [odds ratios (ORs) 1.8-3.8], although associations were only variably significant when controlling for clinical and demographic variables. However, the sum of disorder subtypes was related to odds for PEs in a linear dose-response fashion across all four samples. PEs are related primarily to the extent or severity of psychiatric illness, as indicated by the presence of multiple psychiatric disorders, rather than to any particular subtype of disorder in these data. This relationship applies to the general population and across diverse racial/ethnic groups.

Psychotic Experiences in the Context of Police Victimization: Data From the Survey of Police-Public Encounters.

PubMed

DeVylder, Jordan E; Cogburn, Courtney; Oh, Hans Y; Anglin, Deidre; Smith, Melissa Edmondson; Sharpe, Tanya; Jun, Hyun-Jin; Schiffman, Jason; Lukens, Ellen; Link, Bruce

2017-09-01

Social defeat has been proposed as the common mechanism underlying several well-replicated risk factors for sub-threshold psychotic experiences (PEs) identified in epidemiological research. Victimization by the police may likewise be socially defeating among vulnerable individuals and, therefore, may be associated with elevated risk for PEs. However, no prior studies have examined the relation between police victimization and PEs. We tested the hypothesis that exposure to police victimization (ie, physical, sexual, psychological, and neglect) would be associated with increased odds for PEs in the Survey of Police-Public Encounters data (N = 1615), a general population sample of adults from 4 US cities. Respondents who reported each type of police victimization were more likely to report PEs in logistic regression analyses (all P < .01), most of which were significant even when adjusting for demographic variables, psychological distress, and self-reported crime involvement (adjusted OR range: 1.30 to 7.16). Furthermore, the prevalence of PEs increased with greater exposure to police victimization in a linear dose-response relation, OR (95% CI) = 1.44 (1.24-1.66). These findings suggest that police victimization is a clinically important and previously unreported risk factor for PEs in the urban US population. These findings support the need for community-based outreach efforts and greater police training to reduce the prevalence of this exposure, particularly in socially disadvantaged urban communities. © The Author 2017. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Partially covered self-expandable metal stents versus polyethylene stents for malignant biliary obstruction: A cost-effectiveness analysis

PubMed Central

Barkun, Alan N; Adam, Viviane; Martel, Myriam; AlNaamani, Khalid; Moses, Peter L

2015-01-01

BACKGROUND/OBJECTIVE: Partially covered self-expandable metal stents (SEMS) and polyethylene stents (PES) are both commonly used in the palliation of malignant biliary obstruction. Although SEMS are significantly more expensive, they are more efficacious than PES. Accordingly, a cost-effectiveness analysis was performed. METHODS: A cost-effectiveness analysis compared the approach of initial placement of PES versus SEMS for the study population. Patients with malignant biliary obstruction underwent an endoscopic retrograde cholangiopancreatography to insert the initial stent. If the insertion failed, a percutaneous transhepatic cholangiogram was performed. If stent occlusion occurred, a PES was inserted at repeat endoscopic retrograde cholangiopancreatography, either in an outpatient setting or after admission to hospital if cholangitis was present. A third-party payer perspective was adopted. Effectiveness was expressed as the likelihood of no occlusion over the one-year adopted time horizon. Probabilities were based on a contemporary randomized clinical trial, and costs were issued from national references. Deterministic and probabilistic sensitivity analyses were performed. RESULTS: A PES-first strategy was both more expensive and less efficacious than an SEMS-first approach. The mean per-patient costs were US$6,701 for initial SEMS and US$20,671 for initial PES, which were associated with effectiveness probabilities of 65.6% and 13.9%, respectively. Sensitivity analyses confirmed the robustness of these results. CONCLUSION: At the time of initial endoscopic drainage for patients with malignant biliary obstruction undergoing palliative stenting, an initial SEMS insertion approach was both more effective and less costly than a PES-first strategy. PMID:26125107

Failing to learn from negative prediction errors: Obesity is associated with alterations in a fundamental neural learning mechanism.

PubMed

Mathar, David; Neumann, Jane; Villringer, Arno; Horstmann, Annette

2017-10-01

Prediction errors (PEs) encode the difference between expected and actual action outcomes in the brain via dopaminergic modulation. Integration of these learning signals ensures efficient behavioral adaptation. Obesity has recently been linked to altered dopaminergic fronto-striatal circuits, thus implying impairments in cognitive domains that rely on its integrity. 28 obese and 30 lean human participants performed an implicit stimulus-response learning paradigm inside an fMRI scanner. Computational modeling and psycho-physiological interaction (PPI) analysis was utilized for assessing PE-related learning and associated functional connectivity. We show that human obesity is associated with insufficient incorporation of negative PEs into behavioral adaptation even in a non-food context, suggesting differences in a fundamental neural learning mechanism. Obese subjects were less efficient in using negative PEs to improve implicit learning performance, despite proper coding of PEs in striatum. We further observed lower functional coupling between ventral striatum and supplementary motor area in obese subjects subsequent to negative PEs. Importantly, strength of functional coupling predicted task performance and negative PE utilization. These findings show that obesity is linked to insufficient behavioral adaptation specifically in response to negative PEs, and to associated alterations in function and connectivity within the fronto-striatal system. Recognition of neural differences as a central characteristic of obesity hopefully paves the way to rethink established intervention strategies: Differential behavioral sensitivity to negative and positive PEs should be considered when designing intervention programs. Measures relying on penalization of unwanted behavior may prove less effective in obese subjects than alternative approaches. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pox neuro control of cell lineages that give rise to larval poly-innervated external sensory organs in Drosophila.

PubMed

Jiang, Yanrui; Boll, Werner; Noll, Markus

2015-01-15

The Pox neuro (Poxn) gene of Drosophila plays a crucial role in the development of poly-innervated external sensory (p-es) organs. However, how Poxn exerts this role has remained elusive. In this study, we have analyzed the cell lineages of all larval p-es organs, namely of the kölbchen, papilla 6, and hair 3. Surprisingly, these lineages are distinct from any previously reported cell lineages of sensory organs. Unlike the well-established lineage of mono-innervated external sensory (m-es) organs and a previously proposed model of the p-es lineage, we demonstrate that all wild-type p-es lineages exhibit the following features: the secondary precursor, pIIa, gives rise to all three support cells-socket, shaft, and sheath, whereas the other secondary precursor, pIIb, is neuronal and gives rise to all neurons. We further show that in one of the p-es lineages, that of papilla 6, one cell undergoes apoptosis. By contrast in Poxn null mutants, all p-es lineages have a reduced number of cells and their pattern of cell divisions is changed to that of an m-es organ, with the exception of a lineage in a minority of mutant kölbchen that retains a second bipolar neuron. Indeed, the role of Poxn in p-es lineages is consistent with the specification of the developmental potential of secondary precursors and the regulation of cell division but not apoptosis. Copyright © 2014 Elsevier Inc. All rights reserved.

Status and Perspectives of Clinical Modes in Surgical Patients With Lung Cancer: A Retrospective Study.

PubMed

Lai, Yutian; Du, Heng; Wang, Xin; Shen, Cheng; Huang, Jian; Li, Weiming; Che, Guowei

2016-01-01

To investigate the association between the clinical characteristics and clinical modes of surgically treated lung cancer patients, we conducted a retrospective study with 1097 lung cancer patients receiving pulmonary resection between 2012 and 2013.A physical examination or screening (PES) group (n = 267) and a symptomatic (SY) group (n = 830) were established depending on the new clinical mode (sequence of physical examination, early detection and sequential medical treatment) and the conventional mode (hospitalization due to occurrence of relevant symptoms), respectively.A higher proportion of patients referred to our unit directly form a junior medical unit is found in PES group (43.8%, 117/267 vs 13.6%, 113/830) (P < 0.001) and 37.5% (100/267) patients in PES group spent <1 months from detection or first medical visit to diagnosis compared with 15.4% (128/830) patient in SY group (P < 0.001). A significantly higher proportion of PES patients versus SY patients received video-assisted thoracoscopic surgery (VATS) resection (67.8%, 183/267 vs 42.6%, 352/830; P < 0.001). A significantly higher proportion of PES patients versus SY patients chose sublobar resection (16.9%, 45/267 vs 7.6%, 63/830; P < 0.001). A significantly higher proportion of PES patients versus SY patients are at stage 0 or I (64.4%, 172/267 vs 40.7%, 338/830; P < 0.000). The postoperative incidence rate of complications in 30 days is significantly higher in SY group than in PES group (34.9% vs 27.3%; P = 0.022).Helping to early diagnosis and surgical treatment, early tumor detection via PES may contribute to significantly higher proportions of early-stage lung cancer, use of VATS pulmonary resection, and sublobectomy as well as lower complication rate.

Foot orthoses for adults with flexible pes planus: a systematic review.

PubMed

Banwell, Helen A; Mackintosh, Shylie; Thewlis, Dominic

2014-04-05

Foot orthoses are widely used in the management of flexible pes planus, yet the evidence to support this intervention has not been clearly defined. This systematic review aimed to critically appraise the evidence for the use of foot orthoses for flexible pes planus in adults. Electronic databases (Medline, CINAHL, Cochrane, Web of science, SportDiscus, Embase) were systematically searched in June 2013 for randomised controlled, controlled clinical and repeated measure trials where participants had identified flexible pes planus using a validated and reliable measure of pes planus and the intervention was a rigid or semi-rigid orthoses with the comparison being a no-orthoses (shoes alone or flat non-posted insert) condition. Outcomes of interest were foot pain, rearfoot kinematics, foot kinetics and physical function. Of the 2,211 articles identified by the searches, 13 studies met the inclusion criteria; two were randomised controlled trials, one was a controlled trial and 10 were repeated measure studies. Across the included studies, 59 relevant outcome measures were reported with 17 calculated as statistically significant large or medium effects observed with use of foot orthoses compared to the no orthoses condition (SMD range 1.13 to -4.11). No high level evidence supported the use of foot orthoses for flexible pes planus. There is good to moderate level evidence that foot orthoses improve physical function (medial-lateral sway in standing (level II) and energy cost during walking (level III)). There is low level evidence (level IV) that foot orthoses improve pain, reduce rearfoot eversion, alter loading and impact forces; and reduce rearfoot inversion and eversion moments in flexible pes planus. Well-designed randomised controlled trials that include appropriate sample sizes, clinical cohorts and involve a measure of symptom change are required to determine the efficacy of foot orthoses to manage adult flexible pes planus.

Foot orthoses for adults with flexible pes planus: a systematic review

PubMed Central

2014-01-01

Background Foot orthoses are widely used in the management of flexible pes planus, yet the evidence to support this intervention has not been clearly defined. This systematic review aimed to critically appraise the evidence for the use of foot orthoses for flexible pes planus in adults. Methods Electronic databases (Medline, CINAHL, Cochrane, Web of science, SportDiscus, Embase) were systematically searched in June 2013 for randomised controlled, controlled clinical and repeated measure trials where participants had identified flexible pes planus using a validated and reliable measure of pes planus and the intervention was a rigid or semi-rigid orthoses with the comparison being a no-orthoses (shoes alone or flat non-posted insert) condition. Outcomes of interest were foot pain, rearfoot kinematics, foot kinetics and physical function. Results Of the 2,211 articles identified by the searches, 13 studies met the inclusion criteria; two were randomised controlled trials, one was a controlled trial and 10 were repeated measure studies. Across the included studies, 59 relevant outcome measures were reported with 17 calculated as statistically significant large or medium effects observed with use of foot orthoses compared to the no orthoses condition (SMD range 1.13 to -4.11). Conclusions No high level evidence supported the use of foot orthoses for flexible pes planus. There is good to moderate level evidence that foot orthoses improve physical function (medial-lateral sway in standing (level II) and energy cost during walking (level III)). There is low level evidence (level IV) that foot orthoses improve pain, reduce rearfoot eversion, alter loading and impact forces; and reduce rearfoot inversion and eversion moments in flexible pes planus. Well-designed randomised controlled trials that include appropriate sample sizes, clinical cohorts and involve a measure of symptom change are required to determine the efficacy of foot orthoses to manage adult flexible pes planus. PMID:24708560

Long-term clinical outcomes of 'Prairie Epidemic Strain' Pseudomonas aeruginosa infection in adults with cystic fibrosis.

PubMed

Somayaji, Ranjani; Lam, John C; Surette, Michael G; Waddell, Barbara; Rabin, Harvey R; Sibley, Christopher D; Purighalla, Swathi; Parkins, Michael D

2017-04-01

Epidemic Pseudomonas aeruginosa (PA) plays an important role in cystic fibrosis (CF) lung disease. A novel strain, the 'Prairie Epidemic Strain' (PES), has been identified in up to 30% of patients in Prairie-based Canadian CF centres. To determine the incidence, prevalence and long-term clinical impact of PES infection. A cohort of adults with CF was followed from 1980 to 2014 where bacteria isolated from clinical encounters were prospectively collected. Strain typing was performed using pulse-field gel electrophoresis and multilocus sequence typing. Patients were divided into one of four cohorts: no PA, transient PA, chronic PA with unique strains and chronic PES. Proportional Cox hazard and linear mixed models were used to assess for CF-associated respiratory death or transplantation, and rates of %FEV 1 and body mass index (BMI) decline. 274 patients (51.7% male) were analysed: 44--no PA, 29--transient PA, 137--unique PA, 64--PES. A total of 92 patients (33.6%) died or underwent lung transplantation (2423.0 patient-years). PES infection was associated with greater risk of respiratory death or lung transplant compared with the no PA group (aHR, 3.94 (95% CI 1.18 to 13.1); p=0.03) and unique PA group (aHR, 1.75 (95% CI 1.05 to 2.92) p=0.03). Rate of lung function decline (%FEV 1 predicted) was greatest in the PES group (1.73%/year (95% CI 1.63% to 1.82%); p<0.001). BMI improved over time but at an attenuated rate in the PES group (p=0.001). Infection with PES was associated with increased patient morbidity through three decades and manifested in an increased risk of respiratory death and/or lung transplantation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

In-port derivatization coupled to different extraction techniques for the determination of alkylphenols in environmental water samples.

PubMed

Cavalheiro, J; Monperrus, M; Amouroux, D; Preud'Homme, H; Prieto, A; Zuloaga, O

2014-05-02

Large volume injection (LVI)-in port silylation coupled to gas chromatography-mass spectrometry (GC-MS) for the determination of alkylphenols (APs) in water samples applying four different extraction approaches was evaluated. Among the variables studied for in-port derivatization, vent time, cryo-focusing temperature and the ratio solvent volume/N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) volume were optimized using an experimental design approach. Regarding the extraction techniques, different approaches previously optimized in the research group were tested. On the one hand different polymeric materials were tested: silicon rod (SR), polyethersulfone (PES) and polydimethylsiloxane (PDMS), the latter in the stir-bar sorptive extraction format (SBSE-PDMS). PES was chosen among the polymeric materials due to the higher recoveries (compared with SR) and lower price (compared to PDMS in the stir-bar sorptive extraction, SBSE-PDMS). Both MASE and PES protocols were selected at this point for further method validation and application to real samples. Finally, the developed methods were validated and applied to the determination of target analytes in various aqueous environmental matrices, including estuarine water and wastewater. Acceptable repeatability in the case of MASE (5-17%) and PES (7-21%) procedures and method detection limits (MDLs, 5-123 and 28-328 ng L(-1) for PES and MASE, respectively) were obtained for most analytes. In terms of apparent recoveries in the presence of matrix, estuarine and effluent samples showed no significant matrix effect (apparent recoveries in the 73-121% for PES and 74-128% for MASE), while a stronger matrix effect was observed for influent wastewater samples (98-132% for PES and 65-156% for MASE). Both MASE and PES extractions combined with LVI-in-port derivatization-GC-MS were applied to the determination of APs in the estuary of Bilbao (Gulf of Biscay, Spain). Copyright © 2014 Elsevier B.V. All rights reserved.

A state-specific approach to multireference coupled electron-pair approximation like methods: Development and applications

NASA Astrophysics Data System (ADS)

Chattopadhyay, Sudip; Pahari, Dola; Mukherjee, Debashis; Mahapatra, Uttam Sinha

2004-04-01

The traditional multireference (MR) coupled-cluster (CC) methods based on the effective Hamiltonian are often beset by the problem of intruder states, and are not suitable for studying potential energy surface (PES) involving real or avoided curve crossing. State-specific MR-based approaches obviate this limitation. The state-specific MRCC (SS-MRCC) method developed some years ago [Mahapatra et al., J. Chem. Phys. 110, 6171 (1999)] can handle quasidegeneracy of varying degrees over a wide range of PES, including regions of real or avoided curve-crossing. Motivated by its success, we have suggested and explored in this paper a suite of physically motivated coupled electron-pair approximations (SS-MRCEPA) like methods, which are designed to capture the essential strength of the parent SS-MRCC method without significant sacrificing its accuracy. These SS-MRCEPA theories, like their CC counterparts, are based on complete active space, treat all the reference functions on the same footing and provide a description of potentially uniform precision of PES of states with varying MR character. The combining coefficients of the reference functions are self-consistently determined along with the cluster amplitudes themselves. The newly developed SS-MRCEPA methods are size-extensive, and are also size-consistent with localized orbitals. Among the various versions, there are two which are invariant with respect to the restricted rotations among doubly occupied and active orbitals separately. Similarity of performance of this latter and the noninvariant versions at the crossing points of the degenerate orbitals imply that the all the methods presented are rather robust with respect to the rotations among degenerate orbitals. Illustrative numerical applications are presented for PES of the ground state of a number of difficult test cases such as the model H4, H8 problems, the insertion of Be into H2, and Li2, where intruders exist and for a state of a molecule such as CH2, with pronounced MR character. Results obtained with SS-MRCEPA methods are found to be comparable in accuracy to the parent SS-MRCC and FCI/large scale CI results throughout the PES, which indicates the efficacy of our SS-MRCEPA methods over a wide range of geometries, despite their neglect of a host of complicated nonlinear terms, even when the traditional MR-based methods based on effective Hamiltonians fail due to intruders.

Reinforcement learning signals in the anterior cingulate cortex code for others' false beliefs.

PubMed

Apps, M A J; Green, R; Ramnani, N

2013-01-01

The ability to recognise that another's belief is false is a hallmark of our capacity to understand others' mental states. It has been suggested that the computational and neural mechanisms that underpin learning about others' mental states may be similar to those that underpin first-person Reinforcement Learning (RL). In RL, unexpected decision-making outcomes constitute prediction errors (PE), which are coded for by neurons in the Anterior Cingulate Cortex (ACC). Does the ACC signal the PEs (false beliefs) of others about the outcomes of their decisions? We scanned subjects using fMRI while they monitored a third-person's decisions and similar responses made by a computer. The outcomes of the trials were manipulated, such that the actual outcome was unexpectedly different from the predicted outcome on 1/3 of trials. We examined activity time-locked to privileged information which indicated the actual outcomes only to subjects. Activity in the gyral ACC was found when the outcomes of the third-person's decisions were unexpectedly positive. Activity in the sulcal ACC was found when the third-person's or computer's outcomes were unexpectedly positive. We suggest that a property of the ACC is that it codes PEs, with a portion of the gyral ACC specialised for processing the PEs of others. Copyright © 2012 Elsevier Inc. All rights reserved.

HgCdTe Surface and Defect Study Program.

DTIC Science & Technology

1986-03-01

different potential for Hg and Cd and hence be reflected in the electronic structure. The techniques of PES and ARPES available to our research group ...D-A166 795 HOME SURFCE ND DEFECT STUDY PROQRN(U) SATA / BARBRA RESEARCH CENTER GOLETA CALXF J A WILSON ET AL. USI FE MAR 86 SBRC-60411 ND93-63-C...0168 FO2/2 N L6 ILO 1.5 1. 11111 .6 .ICnrnp CHR HgCdTo SURFACE AND DEFECT STUDY PROGRAM J. A. Wilson and V. A. Cotton Santa Barbara Research Center

HgCdTe Surface Study Program

DTIC Science & Technology

1982-09-01

which the virtual crystal approximation breaks down using PES. This is well understood and was confirmed theoretically , working with Arden Sher of SRI...Quasistatic Capacitance of SiC on Hg07 Cd0 Te Treated with HF to Remove Native Oxide, Compared to Theoretical Curve...MIS devices show near ideal behav- ior. Figure I shows capacitance data taken quasistatically and at 1 MHz (dashed curves), compared to a theoretically

Multidimensionally constrained relativistic mean-field study of triple-humped barriers in actinides

NASA Astrophysics Data System (ADS)

Zhao, Jie; Lu, Bing-Nan; Vretenar, Dario; Zhao, En-Guang; Zhou, Shan-Gui

2015-01-01

Background: Potential energy surfaces (PES's) of actinide nuclei are characterized by a two-humped barrier structure. At large deformations beyond the second barrier, the occurrence of a third barrier was predicted by macroscopic-microscopic model calculations in the 1970s, but contradictory results were later reported by a number of studies that used different methods. Purpose: Triple-humped barriers in actinide nuclei are investigated in the framework of covariant density functional theory (CDFT). Methods: Calculations are performed using the multidimensionally constrained relativistic mean field (MDC-RMF) model, with the nonlinear point-coupling functional PC-PK1 and the density-dependent meson exchange functional DD-ME2 in the particle-hole channel. Pairing correlations are treated in the BCS approximation with a separable pairing force of finite range. Results: Two-dimensional PES's of 226,228,230,232Th and 232,235,236,238U are mapped and the third minima on these surfaces are located. Then one-dimensional potential energy curves along the fission path are analyzed in detail and the energies of the second barrier, the third minimum, and the third barrier are determined. The functional DD-ME2 predicts the occurrence of a third barrier in all Th nuclei and 238U . The third minima in 230 ,232Th are very shallow, whereas those in 226 ,228Th and 238U are quite prominent. With the functional PC-PK1 a third barrier is found only in 226 ,228 ,230Th . Single-nucleon levels around the Fermi surface are analyzed in 226Th, and it is found that the formation of the third minimum is mainly due to the Z =90 proton energy gap at β20≈1.5 and β30≈0.7 . Conclusions: The possible occurrence of a third barrier on the PES's of actinide nuclei depends on the effective interaction used in multidimensional CDFT calculations. More pronounced minima are predicted by the DD-ME2 functional, as compared to the functional PC-PK1. The depth of the third well in Th isotopes decreases with increasing neutron number. The origin of the third minimum is due to the proton Z =90 shell gap at relevant deformations.

Stochastic many-body perturbation theory for anharmonic molecular vibrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hermes, Matthew R.; Hirata, So, E-mail: sohirata@illinois.edu; CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012

2014-08-28

A new quantum Monte Carlo (QMC) method for anharmonic vibrational zero-point energies and transition frequencies is developed, which combines the diagrammatic vibrational many-body perturbation theory based on the Dyson equation with Monte Carlo integration. The infinite sums of the diagrammatic and thus size-consistent first- and second-order anharmonic corrections to the energy and self-energy are expressed as sums of a few m- or 2m-dimensional integrals of wave functions and a potential energy surface (PES) (m is the vibrational degrees of freedom). Each of these integrals is computed as the integrand (including the value of the PES) divided by the value ofmore » a judiciously chosen weight function evaluated on demand at geometries distributed randomly but according to the weight function via the Metropolis algorithm. In this way, the method completely avoids cumbersome evaluation and storage of high-order force constants necessary in the original formulation of the vibrational perturbation theory; it furthermore allows even higher-order force constants essentially up to an infinite order to be taken into account in a scalable, memory-efficient algorithm. The diagrammatic contributions to the frequency-dependent self-energies that are stochastically evaluated at discrete frequencies can be reliably interpolated, allowing the self-consistent solutions to the Dyson equation to be obtained. This method, therefore, can compute directly and stochastically the transition frequencies of fundamentals and overtones as well as their relative intensities as pole strengths, without fixed-node errors that plague some QMC. It is shown that, for an identical PES, the new method reproduces the correct deterministic values of the energies and frequencies within a few cm{sup −1} and pole strengths within a few thousandths. With the values of a PES evaluated on the fly at random geometries, the new method captures a noticeably greater proportion of anharmonic effects.« less

Plasma application for detoxification of Jatropha phorbol esters

NASA Astrophysics Data System (ADS)

Kongmany, S.; Matsuura, H.; Furuta, M.; Okuda, S.; Imamura, K.; Maeda, Y.

2013-06-01

Atmospheric pressure non-thermal dielectric barrier discharge (DBD) plasma generated by helium gas at high voltage and input power of about 50 W was first applied to detoxification of Jatropha curcas phorbol esters (J. PEs) as well as standard phorbol ester (4β-12-O-tetradecanoyl phorbol-13-acetate, TPA) in water and methanol. Plasma irradiation on the solution sample was conducted for 15 min. In aqueous solution, only 16% of TPA was degraded and complete degradation of J. PEs was observed. On the contrary, complete degradation of both TPA and J. PEs in methanol was achieved by the same plasma irradiation condition. Hydroxyl radical (•OH) generated by plasma irradiation of the solution is expected as the main radical inducing the degradation of PEs.

Testing prospectively the effectiveness and safety of paclitaxel-eluting stents in over 1000 very high-risk patients: design, baseline characteristics, procedural data and in-hospital outcomes of the multicenter Taxus in Real-life Usage Evaluation (TRUE) Study.

PubMed

Biondi-Zoccai, Giuseppe G L; Sangiorgi, Giuseppe M; Antoniucci, David; Grube, Eberhard; Di Mario, Carlo; Reimers, Bernard; Tamburino, Corrado; Agostoni, Pierfrancesco; Cosgrave, John; Colombo, Antonio

2007-05-02

Paclitaxel-eluting stents (PES) have been proved effective in randomized trials enrolling highly selected patients. Yet, given the uncertainty concerning results of PES implantation in very high-risk patients and lesions, we designed a prospective multicenter registry, the Taxus in Real-life Usage Evaluation (TRUE) Study. STUDY DESIGN, PATIENT CHARACTERISTICS AND IN-HOSPITAL OUTCOMES: Consecutive patients undergoing PES implantation were enrolled provided that the target lesion treated with PES was an unprotected left main (ULM), a true bifurcation, a chronic total occlusion (CTO), a long lesion (>28 mm), located in a small vessel (<2.75 mm), or the patient had diabetes mellitus. Clinical events will be adjudicated at 1, 7 and 12 months, with 4- to 8-month angiographic follow-up. The primary end-point will be the 7-month occurrence of major adverse cardiovascular events (MACE, i.e. the composite of cardiac death, non-fatal myocardial infarction [MI], coronary artery bypass grafting [CABG] and percutaneous target vessel revascularization [TVR]). To date, patient enrollment has been completed reaching the target of 1065 subjects. These included 322 (30.2%) diabetics, 115 (10.8%) subjects undergoing PES implantation for ULM, 229 (21.5%) in a bifurcation, 191 (17.9%) in a CTO, 430 (40.4%) in a small vessel, and 289 (27.1%) in a long lesion. An average of 1.5+/-0.6 vessels and 2.0+/-1.0 lesions were treated per patient, with 2.0+/-1.2 PES implanted per patient, and a 46+/-30 mm total PES length per patient. In-hospital MACE occurred in 39 (3.7%) patients, with 2 (0.2%) cardiac deaths, 32 (3.0%) MI, 5 (0.5%) TVR, no CABG, and 4 (0.4%) acute stent thromboses. Despite the availability of randomized trials, only carefully designed and prospective registries can provide timely and accurate assessment of the risk-benefit profile of PES in very high-risk patients. Indeed, the TRUE Study, including as much as 115 ULM and 229 bifurcation interventions, should give important insights into the outcome of PES in such an unprecedented and challenging context.

The association between psychotic experiences and health-related quality of life: a cross-national analysis based on World Mental Health Surveys.

PubMed

Alonso, Jordi; Saha, Sukanta; Lim, Carmen C W; Aguilar-Gaxiola, Sergio; Al-Hamzawi, Ali; Benjet, Corina; Bromet, Evelyn J; Degenhardt, Louisa; de Girolamo, Giovanni; Esan, Oluyomi; Florescu, Silvia; Gureje, Oye; Haro, Josep M; Hu, Chiyi; Karam, Elie G; Karam, Georges; Kovess-Masfety, Viviane; Lepine, Jean-Pierre; Lee, Sing; Mneimneh, Zeina; Navarro-Mateu, Fernando; Posada-Villa, Jose; Sampson, Nancy A; Scott, Kate M; Stagnaro, Juan Carlos; Ten Have, Margreet; Viana, Maria Carmen; Kessler, Ronald C; McGrath, John J

2018-05-16

Psychotic experiences (PEs) are associated with a range of mental and physical disorders, and disability, but little is known about the association between PEs and aspects of health-related quality of life (HRQoL). We aimed to investigate the association between PEs and five HRQoL indicators with various adjustments. Using data from the WHO World Mental Health surveys (n = 33,370 adult respondents from 19 countries), we assessed for PEs and five HRQoL indicators (self-rated physical or mental health, perceived level of stigma (embarrassment and discrimination), and social network burden). Logistic regression models that adjusted for socio-demographic characteristics, 21 DSM-IV mental disorders, and 14 general medical conditions were used to investigate the associations between the variables of interest. We also investigated dose-response relationships between PE-related metrics (number of types and frequency of episodes) and the HRQoL indicators. Those with a history of PEs had increased odds of poor perceived mental (OR = 1.5, 95% CI = 1.2-1.9) and physical health (OR = 1.3, 95% CI = 1.0-1.7) after adjustment for the presence of any mental or general medical conditions. Higher levels of perceived stigma and social network burden were also associated with PEs in the adjusted models. Dose-response associations between PE type and frequency metrics and subjective physical and mental health were non-significant, except those with more PE types had increased odds of reporting higher discrimination (OR = 2.2, 95% CI = 1.3-3.5). Our findings provide novel insights into how those with PEs perceive their health status. Copyright © 2018. Published by Elsevier B.V.

Evidence that the presence of psychosis in non-psychotic disorder is environment-dependent and mediated by severity of non-psychotic psychopathology.

PubMed

Guloksuz, S; van Nierop, M; Lieb, R; van Winkel, R; Wittchen, H-U; van Os, J

2015-08-01

Evidence suggests that in affective, non-psychotic disorders: (i) environmental exposures increase risk of subthreshold psychotic experiences (PEs) and strengthen connectivity between domains of affective and subthreshold psychotic psychopathology; and (ii) PEs are a marker of illness severity. In 3021 adolescents from the Early Developmental Stages of Psychopathology cohort, we tested whether the association between PEs and presence of DSM-IV mood disorder (MD)/obsessive-compulsive disorder (OCD) would be moderated by risk factors for psychosis (cannabis use, childhood trauma and urbanicity), using the interaction contrast ratio (ICR) method. Furthermore, we analysed whether the interaction between environment and PEs was mediated by non-psychotic psychopathology. The association between PEs and MD/OCD was moderated by urbanicity (ICR = 2.46, p = 0.005), cannabis use (ICR = 3.76, p = 0.010) and, suggestively, trauma (ICR = 1.91, p = 0.063). Exposure to more than one environmental risk factor increased the likelihood of co-expression of PEs in a dose-response fashion. Moderating effects of environmental exposures were largely mediated by the severity of general non-psychotic psychopathology (percentage explained 56-68%, all p < 0.001). Within individuals with MD/OCD, the association between PEs and help-seeking behaviour, as an index of severity, was moderated by trauma (ICR = 1.87, p = 0.009) and urbanicity (ICR = 1.48, p = 0.005), but not by cannabis use. In non-psychotic disorder, environmental factors increase the likelihood of psychosis admixture and help-seeking behaviour through an increase in general psychopathology. The findings are compatible with a relational model of psychopathology in which more severe clinical states are the result of environment-induced disturbances spreading through a psychopathology network.

Psychotic experiences are linked to cannabis use in adolescents in the community because of common underlying environmental risk factors.

PubMed

Shakoor, Sania; Zavos, Helena M S; McGuire, Philip; Cardno, Alastair G; Freeman, Daniel; Ronald, Angelica

2015-06-30

Cannabis users are more likely to have psychotic experiences (PEs). The degree to which these associations are driven by genetic or environmental influences in adolescence is unknown. This study estimated the genetic and environmental contributions to the relationship between cannabis use and PEs. Specific PEs were measured in a community-based twin sample (4830 16-year-old pairs) using self-reports and parent-reports. Adolescents reported on ever using cannabis. Multivariate liability threshold structural equation model-fitting was conducted. Cannabis use was significantly correlated with PEs. Modest heritability (37%), common environmental influences (55%) and unique environment (8%) were found for cannabis use. For PEs, modest heritability (27-54%), unique environmental influences (E=12-50%) and little common environmental influences (11-20%), with the exception of parent-rated Negative Symptoms (42%), were reported. Environmental influences explained all of the covariation between cannabis use and paranoia, cognitive disorganization and parent-rated negative symptoms (bivariate common environment=69-100%, bivariate unique environment=28-31%), whilst the relationship between cannabis use and hallucinations indicated familial influences. Cannabis use explains 2-5% of variance in positive, cognitive, and negative PEs. Cannabis use and psychotic experience co-occur due to environmental factors. Focus on specific environments may reveal why adolescent cannabis use and psychotic experiences tend to 'travel together'. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene

PubMed Central

Hazarika, Ankita; Deka, Biplab K.; Kim, DoYoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

2017-01-01

We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90–100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene. PMID:28074877

Psychotic experiences are linked to cannabis use in adolescents in the community because of common underlying environmental risk factors

PubMed Central

Shakoor, Sania; Zavos, Helena M.S.; McGuire, Philip; Cardno, Alastair G.; Freeman, Daniel; Ronald, Angelica

2015-01-01

Cannabis users are more likely to have psychotic experiences (PEs). The degree to which these associations are driven by genetic or environmental influences in adolescence is unknown. This study estimated the genetic and environmental contributions to the relationship between cannabis use and PEs. Specific PEs were measured in a community-based twin sample (4830 16-year-old pairs) using self-reports and parent-reports. Adolescents reported on ever using cannabis. Multivariate liability threshold structural equation model-fitting was conducted. Cannabis use was significantly correlated with PEs. Modest heritability (37%), common environmental influences (55%) and unique environment (8%) were found for cannabis use. For PEs, modest heritability (27–54%), unique environmental influences (E=12–50%) and little common environmental influences (11–20%), with the exception of parent-rated Negative Symptoms (42%), were reported. Environmental influences explained all of the covariation between cannabis use and paranoia, cognitive disorganization and parent-rated negative symptoms (bivariate common environment=69–100%, bivariate unique environment=28–31%), whilst the relationship between cannabis use and hallucinations indicated familial influences. Cannabis use explains 2–5% of variance in positive, cognitive, and negative PEs. Cannabis use and psychotic experience co-occur due to environmental factors. Focus on specific environments may reveal why adolescent cannabis use and psychotic experiences tend to ‘travel together’. PMID:25912376

Psychosis-inducing effects of cannabis are related to both childhood abuse and COMT genotypes.

PubMed

Alemany, S; Arias, B; Fatjó-Vilas, M; Villa, H; Moya, J; Ibáñez, M I; Ortet, G; Gastó, C; Fañanás, L

2014-01-01

To test whether the association between childhood abuse, cannabis use and psychotic experiences (PEs) was moderated by the COMT (catechol-O-methyltransferase) gene. Psychotic experiences (PEs), childhood abuse, cannabis use and COMT Val158Met genotypes were assessed in 533 individuals from the general population. Data were analysed hierarchically by means of multiple linear regression models. Childhood abuse showed a significant main effect on both positive (β = 0.09; SE = 0.04; P = 0.047) and negative PEs (β = 0.11; SE = 0.05; P = 0.038). A significant three-way interaction effect was found among childhood abuse, cannabis use and the COMT gene on positive PEs (β = -0.30; SE = 0.11; P = 0.006). This result suggests that COMT genotypes and cannabis use only influenced PE scores among individuals exposed to childhood abuse. Furthermore, exposure to childhood abuse and cannabis use increased PE scores in Val carriers. However, in individuals exposed to childhood abuse but who did not use cannabis, PEs increased as a function of the Met allele copies of the COMT gene. Cannabis use after exposure to childhood abuse may have opposite effects on the risk of PEs, depending on the COMT genotypes providing evidence for a qualitative interaction. Val carriers exposed to childhood abuse are vulnerable to the psychosis-inducing effects of cannabis. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Is there any sense in the Palisade endings of eye muscles?

PubMed Central

Lienbacher, Karoline; Mustari, Michael; Hess, Bernhard; Büttner-Ennever, Jean; Horn, Anja K.E.

2015-01-01

Palisade endings (PEs), which are unique to the eye muscles, are associated with multiply innervated muscle fibers. They lie at the myotendinous junctions and form a cap around the muscle fiber tip. They are found in all animals investigated so far, but their function is not known. Recently, we demonstrated that cell bodies of PEs and tendon organs lie around the periphery of the oculomotor nucleus in the C- and S-groups. A morphological analysis of these peripheral neurons revealed the existence of different populations within the C-group. We propose that a small group of round or spindle-shaped cells gives rise to PEs, and another group of multipolar neurons provide the multiple motor endings. If PEs have a sensory function, then their cell body location close to motor neurons would be in an ideal location to control tension in extraocular muscles; in the case of the C-group, its proximity to the preganglionic neurons of the Edinger–Westphal nucleus would permit its participation in the near response. Despite their unusual properties, PEs may have a sensory function. PMID:21950969

Is there any sense in the Palisade endings of eye muscles?

PubMed

Lienbacher, Karoline; Mustari, Michael; Hess, Bernhard; Büttner-Ennever, Jean; Horn, Anja K E

2011-09-01

Palisade endings (PEs), which are unique to the eye muscles, are associated with multiply innervated muscle fibers. They lie at the myotendinous junctions and form a cap around the muscle fiber tip. They are found in all animals investigated so far, but their function is not known. Recently, we demonstrated that cell bodies of PEs and tendon organs lie around the periphery of the oculomotor nucleus in the C- and S-groups. A morphological analysis of these peripheral neurons revealed the existence of different populations within the C-group. We propose that a small group of round or spindle-shaped cells gives rise to PEs, and another group of multipolar neurons provide the multiple motor endings. If PEs have a sensory function, then their cell body location close to motor neurons would be in an ideal location to control tension in extraocular muscles; in the case of the C-group, its proximity to the preganglionic neurons of the Edinger-Westphal nucleus would permit its participation in the near response. Despite their unusual properties, PEs may have a sensory function. © 2011 New York Academy of Sciences.

Postextrasystolic potentiation and contractile reserve: requirements and restrictions.

PubMed

Lust, R M; Lutherer, L O; Gardner, M E; Cooper, M W

1982-12-01

These studies were conducted to examine the basic characteristics of postextrasystolic potentiation (PESP) and the relationship of loading effects to PESP. Measurements of left ventricular (LV) and aortic pressures, the rate of pressure rise, and echocardiographically determined LV dimensions were made in anesthetized open-chest dogs. The hearts were paced, and timed extrasystoles were introduced that were followed by postextrasystoles (PES). PES's were elicited after an interval equal to either a full compensatory pause or a time when the diastolic properties of the LV could not be distinguished from control (isolength). Potentiation of contraction for the PES's introduced after an isolength pause was dependent on both the heart rate and the extrasystolic interval, whereas the PES's that occurred after a full pause showed no dependence on either of these intervals. PESP elicited during the isolength period was not dependent on either preload and afterload. It is concluded that PESP depends on the combination of heart rate and extrasystolic and postextrasystolic intervals. Further, PESP may be inaccurate in assessing contractile reserve unless the heart rate and extrasystolic interval are known and the PES is introduced after an isolength pause.

Mean platelet volume in pseudoexfoliation syndrome and glaucoma.

PubMed

Türkcü, Fatih Mehmet; Yüksel, Harun; Sahin, Alparslan; Cinar, Yasin; Yüksel, Hatice; Cingü, Kürşat; Sahin, Muhammed; Yildirim, Adnan; Çaça, Ihsan

2014-01-01

Pseudoexfoliation (PEX) syndrome (PES) is characterized by the widespread deposition of abnormal extracellular fibrillary material on many ocular and extraocular tissues. The objective of this study was to evaluate the association among PES, PEX glaucoma (PEG), and mean platelet volume (MPV). Forty patients with PES (mean age 62.6 ± 7.8 years), 31 with PEG (mean age 65.9 ± 6.6 years), and 37 healthy individuals (control group) (mean age 64.0 ± 7.1 years) were included in the study. The MPV of the 3 groups were compared. Age and sex distribution were similar among groups (p>0.05). Mean MPV in PES, PEG, and control groups were 9.59 ± 0.94 fl, 9.53 ± 0.80 fl, and 7.7 ± 0.67 fl, respectively. In the PEX group, MPV values were significantly higher than in the control group (p<0.05). However, there was no difference between the PES and PEG groups (p>0.05). The MPV values in both groups with PEX were higher than those in the healthy group.

Designing payments for ecosystem services: Lessons from previous experience with incentive-based mechanisms

PubMed Central

Jack, B. Kelsey; Kousky, Carolyn; Sims, Katharine R. E.

2008-01-01

Payments for ecosystem services (PES) policies compensate individuals or communities for undertaking actions that increase the provision of ecosystem services such as water purification, flood mitigation, or carbon sequestration. PES schemes rely on incentives to induce behavioral change and can thus be considered part of the broader class of incentive- or market-based mechanisms for environmental policy. By recognizing that PES programs are incentive-based, policymakers can draw on insights from the substantial body of accumulated knowledge about this class of instruments. In particular, this article offers a set of lessons about how the environmental, socioeconomic, political, and dynamic context of a PES policy is likely to interact with policy design to produce policy outcomes, including environmental effectiveness, cost-effectiveness, and poverty alleviation. PMID:18621696

Designing payments for ecosystem services: Lessons from previous experience with incentive-based mechanisms.

PubMed

Jack, B Kelsey; Kousky, Carolyn; Sims, Katharine R E

2008-07-15

Payments for ecosystem services (PES) policies compensate individuals or communities for undertaking actions that increase the provision of ecosystem services such as water purification, flood mitigation, or carbon sequestration. PES schemes rely on incentives to induce behavioral change and can thus be considered part of the broader class of incentive- or market-based mechanisms for environmental policy. By recognizing that PES programs are incentive-based, policymakers can draw on insights from the substantial body of accumulated knowledge about this class of instruments. In particular, this article offers a set of lessons about how the environmental, socioeconomic, political, and dynamic context of a PES policy is likely to interact with policy design to produce policy outcomes, including environmental effectiveness, cost-effectiveness, and poverty alleviation.

Pharmacists' interventions in prescribing errors at hospital discharge: an observational study in the context of an electronic prescribing system in a UK teaching hospital.

PubMed

Abdel-Qader, Derar H; Harper, Lindsay; Cantrill, Judith A; Tully, Mary P

2010-11-01

Pharmacists have an essential role in improving drug usage and preventing prescribing errors (PEs). PEs at the interface of care are common, sometimes leading to adverse drug events (ADEs). This was the first study to investigate, using a computerized search method, the number, types, severity, pharmacists' impact on PEs and predictors of PEs in the context of electronic prescribing (e-prescribing) at hospital discharge. This was a retrospective, observational, 4-week study, carried out in 2008 in the Medical and Elderly Care wards of a 904-bed teaching hospital in the northwest of England, operating an e-prescribing system at discharge. Details were obtained, using a systematic computerized search of the system, of medication orders either entered by doctors and discontinued by pharmacists or entered by pharmacists. Meetings were conducted within 5 days of data extraction with pharmacists doing their routine clinical work, who categorized the occurrence, type and severity of their interventions using a scale. An independent senior pharmacist retrospectively rated the severity and potential impact, and subjectively judged, based on experience, whether any error was a computer-related error (CRE). Discrepancies were resolved by multidisciplinary discussion. The Statistical Package for Social Sciences was used for descriptive data analysis. For the PE predictors, a multivariate logistic regression was performed using STATA 7. Nine predictors were selected a priori from available prescribers', patients' and drug data. There were 7920 medication orders entered for 1038 patients (doctors entered 7712 orders; pharmacists entered 208 omitted orders). There were 675 (8.5% of 7920) interventions by pharmacists; 11 were not associated with PEs. Incidences of erroneous orders and patients with error were 8.0% (95% CI 7.4, 8.5 [n = 630/7920]) and 20.4% (95% CI 18.1, 22.9 [n = 212/1038]), respectively. The PE incidence was 8.4% (95% CI 7.8, 9.0 [n = 664/7920]). The top three medications associated with PEs were paracetamol (acetaminophen; 30 [4.8%]), salbutamol (albuterol; 28 [4.4%]) and omeprazole (25 [4.0%]). Pharmacists intercepted 524 (83.2%) erroneous orders without referring to doctors, and 70% of erroneous orders within 24 hours. Omission (31.0%), drug selection (29.4%) and dosage regimen (18.1%) error types accounted for >75% of PEs. There were 18 (2.9%) serious, 481 (76.3%) significant and 131 (20.8%) minor erroneous orders. Most erroneous orders (469 [74.4%]) were rated as of significant severity and significant impact of pharmacists on PEs. CREs (n = 279) accounted for 44.3% of erroneous orders. There was a significant difference in severity between CREs and non-CREs (χ2 = 38.88; df = 4; p < 0.001), with CREs being less severe than non-CREs. Drugs with multiple oral formulations (odds ratio [OR] 2.1; 95% CI 1.25, 3.37; p = 0.004) and prescribing by junior doctors (OR 2.54; 95% CI 1.08, 5.99; p = 0.03) were significant predictors of PEs. PEs commonly occur at hospital discharge, even with the use of an e-prescribing system. User and computer factors both appeared to contribute to the high error rate. The e-prescribing system facilitated the systematic extraction of data to investigate PEs in hospital practice. Pharmacists play an important role in rapidly documenting and preventing PEs before they reach and possibly harm patients. Pharmacists should understand CREs, so they complement, rather than duplicate, the e-prescribing system's strengths.

Electronic structure at transition metal phthalocyanine-transition metal oxide interfaces: Cobalt phthalocyanine on epitaxial MnO films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glaser, Mathias; Peisert, Heiko, E-mail: heiko.peisert@uni-tuebingen.de; Adler, Hilmar

2015-03-14

The electronic structure of the interface between cobalt phthalocyanine (CoPc) and epitaxially grown manganese oxide (MnO) thin films is studied by means of photoemission (PES) and X-ray absorption spectroscopy (XAS). Our results reveal a flat-lying adsorption geometry of the molecules on the oxide surface which allows a maximal interaction between the π-system and the substrate. A charge transfer from MnO, in particular, to the central metal atom of CoPc is observed by both PES and XAS. The change of the shape of N-K XAS spectra at the interface points, however, to the involvement of the Pc macrocycle in the chargemore » transfer process. As a consequence of the charge transfer, energetic shifts of MnO related core levels were observed, which are discussed in terms of a Fermi level shift in the semiconducting MnO films due to interface charge redistribution.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Hongwei, E-mail: hwsong@wipm.ac.cn; Yang, Minghui; Lu, Yunpeng

An initial state selected time-dependent wave packet method is applied to study the dynamics of the OH + CHD{sub 3} reaction with a six-dimensional model on a newly developed full-dimensional ab initio potential energy surface (PES). This quantum dynamical (QD) study is complemented by full-dimensional quasi-classical trajectory (QCT) calculations on the same PES. The QD results indicate that both translational energy and the excitation of the CH stretching mode significantly promote the reaction while the excitation of the umbrella mode has a negligible effect on the reactivity. For this early barrier reaction, interestingly, the CH stretching mode is more effectivemore » than translational energy in promoting the reaction except at very low collision energies. These QD observations are supported by QCT results. The higher efficacy of the CH stretching model in promoting this early barrier reaction is inconsistent with the prediction of the naively extended Polanyi’s rules, but can be rationalized by the recently proposed sudden vector projection model.« less

Quenching from highly-excited SiO rotational levels due to H2 collision

NASA Astrophysics Data System (ADS)

Stancil, Phillip C.; Belayneh, Michael; Wan, Yier; Yang, Benhui H.

2018-06-01

Using a full quantum-mechanical close-coupling approach on a 4D rigid-rotor potential energy surface (PES), we performed scattering calculations for highly-excited rotational levels (j=6-10) of SiO for interactions with H2 for the first time. Emission lines from highly excited SiO rotational levels are observed in a variety of environments including outflows from AGB stars. However, explicit collisional data are lacking for H2 colliders, except for recent work from our group for j=1-5. Here we extend that work using a hybrid OpenMP/MPI scattering code and a PES computed at the CCSD(T)-F12b level of theory. The H2 and SiO bond lengths are fixed at their equilibrium values. The current results will allow for non-local thermodynamic models of SiO rotational emission from AGB stars. This work was funded by NASA grant NNX16AF09G.

Polyelectrolyte multilayer capsules as vehicles with tunable permeability.

PubMed

Antipov, Alexei A; Sukhorukov, Gleb B

2004-11-29

This review is devoted to a novel type of polymer micro- and nanocapsules. The shell of the capsule is fabricated by alternate adsorption of oppositely charged polyelectrolytes (PEs) onto the surface of colloidal particles. Cores of different nature (organic or inorganic) with size varied from 0.1 to 10 mum can be used for templating such PE capsules. The shell thickness can be tuned in nanometer range by assembling of defined number of PE layers. The permeability of capsules depends on the pH, ionic strength, solvent, polymer composition, and shell thickness; it can be controlled and varied over wide range of substances regarding their molecular weight and charge. Including functional polymers into capsule wall, such as weak PEs or thermosensitive polymers, makes the capsule permeability sensitive to correspondent external stimuli. Permeability of the capsules is of essential interest in diverse areas related to exploitation of systems with controlled and sustained release properties. The envisaged applications of such capsules/vesicles cover biotechnology, medicine, catalysis, food industry, etc.

Antibacterial surface modified of novel nanocomposite sulfonated polyethersulfone/polyrhodanine membrane

NASA Astrophysics Data System (ADS)

Rostam, Abbas Babaei; Peyravi, Majid; Ghorbani, Mohsen; Jahanshahi, Mohsen

2018-01-01

In this study, sulfonated-polyethersulfone/polyrhodanine (SPES/PRh) membranes with antibacterial behavior were fabricated. Polyethersulfone (PES) sulfonation was performed to enhance its hydrophilicity and next polyrhodanine nanoparticles (PRhNPs) were synthesized along with the sulfonated PES (SPES) by polyrhodanine (PRh) in situ polymerization. The sulfonation step also helps making composite membrane due to development of probable bondings and polymers engagements. The constructed membranes characterization was performed by FTIR, FESEM, contact angle, 1H NMR, TGA and EDS analyses. SPES/PRh membrane had enhanced hydrophilicity and consequently better fluxes for aqueous solutions. The composite SPES/PRh membrane flux was improved to 139/78 L/m2 h comparing 58.21 L/m2 h for SPES one. Membrane operational performances, antibacterial and antibiofouling tests showed improved flux, better rejection and appropriate antibacterial and antibiofouling properties for SPES/PRh membrane. The 100% bacteria mortality for specified concentrations and appropriate inhibition zones up to 9 mm have been achieved. It is generally a suitable membrane to provide proper performance beside antibacterial and antibiofouling behavior.

Rotational Spectroscopy of the NH3-H2 Molecular Complex

NASA Astrophysics Data System (ADS)

Surin, L. A.; Tarabukin, I. V.; Schlemmer, S.; Breier, A. A.; Giesen, T. F.; McCarthy, M. C.; van der Avoird, A.

2017-03-01

We report the first high resolution spectroscopic study of the NH3-H2 van der Waals molecular complex. Three different experimental techniques, a molecular beam Fourier transform microwave spectrometer, a millimeter-wave intracavity jet OROTRON spectrometer, and a submillimeter-wave jet spectrometer with multipass cell, were used to detect pure rotational transitions of NH3-H2 in the wide frequency range from 39 to 230 GHz. Two nuclear spin species, (o)-NH3-(o)-H2 and (p)-NH3-(o)-H2, have been assigned as carriers of the observed lines on the basis of accompanying rovibrational calculations performed using the ab initio intermolecular potential energy surface (PES) of Maret et al. The experimental spectra were compared with the theoretical bound state results, thus providing a critical test of the quality of the NH3-H2 PES, which is a key issue for reliable computations of the collisional excitation and de-excitation of ammonia in the dense interstellar medium.

Pulsed Plasma Electron Sources

NASA Astrophysics Data System (ADS)

Krasik, Yakov

2008-11-01

Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E < 10^5 V/cm this plasma is not uniform and there is a time delay in its formation. Thus, there is a continuous interest in research of electron sources which can be used for generation of uniform electron beams produced at E <= 10^5 V/cm. In the present report, several types of plasma electron source (PES) will be considered. The first type of PES is fiber-based cathodes, with and without CsI coating. The operation of these cathodes is governed by the formation of the flashover plasma which serves as a source of electrons. The second type of PES is the ferroelectric plasma source (FPS). The operation of FPS, characterized by the formation of dense surface flashover plasma is accompanied also by the generation of fast microparticles and energetic neutrals. The latter was explained by Coulomb micro-explosions of the ferroelectric surface due to an large time-varying electric field at the front of the expanding plasma. A short review of recent achievements in the operation of a multi-FPS-assisted hollow anode to generate a large area electron beam will be presented as well. Finally, parameters of the plasma produced by a multi-capillary cathode with FPS and velvet igniters will be discussed. Ya. E. Krasik, J. Z. Gleizer, D. Yarmolich, A. Krokhmal, V. Ts. Gurovich, S.Efimov, J. Felsteiner V. Bernshtam, and Yu. M. Saveliev, J. Appl. Phys. 98, 093308 (2005). Ya. E. Krasik, A. Dunaevsky, and J. Felsteiner, Phys. Plasmas 8, 2466 (2001). D. Yarmolich, V. Vekselman, V. Tz. Gurovich, and Ya. E. Krasik, Phys. Rev. Lett. 100, 075004 (2008). J. Z. Gleizer, Y. Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

On the accuracy of explicitly correlated methods to generate potential energy surfaces for scattering calculations and clustering: application to the HCl-He complex.

PubMed

Ajili, Yosra; Hammami, Kamel; Jaidane, Nejm Eddine; Lanza, Mathieu; Kalugina, Yulia N; Lique, François; Hochlaf, Majdi

2013-07-07

We closely compare the accuracy of multidimensional potential energy surfaces (PESs) generated by the recently developed explicitly correlated coupled cluster (CCSD(T)-F12) methods in connection with the cc-pVXZ-F12 (X = D, T) and aug-cc-pVTZ basis sets and those deduced using the well-established orbital-based coupled cluster techniques employing correlation consistent atomic basis sets (aug-cc-pVXZ, X = T, Q, 5) and extrapolated to the complete basis set (CBS) limit. This work is performed on the benchmark rare gas-hydrogen halide interaction (HCl-He) system. These PESs are then incorporated into quantum close-coupling scattering dynamical calculations in order to check the impact of the accuracy of the PES on the scattering calculations. For this system, we deduced inelastic collisional data including (de-)excitation collisional and pressure broadening cross sections. Our work shows that the CCSD(T)-F12/aug-cc-pVTZ PES describes correctly the repulsive wall, the van der Waals minimum and long range internuclear distances whereas cc-pVXZ-F12 (X = D,T) basis sets are not diffuse enough for that purposes. Interestingly, the collision cross sections deduced from the CCSD(T)-F12/aug-cc-pVTZ PES are in excellent agreement with those obtained with CCSD(T)/CBS methodology. The position of the resonances and the general shape of these cross sections almost coincide. Since the cost of the electronic structure computations is reduced by several orders of magnitude when using CCSD(T)-F12/aug-cc-pVTZ compared to CCSD(T)/CBS methodology, this approach can be recommended as an alternative for generation of PESs of molecular clusters and for the interpretation of accurate scattering experiments as well as for a wide production of collisional data to be included in astrophysical and atmospherical models.

Radiographic protocol and normal anatomy of the hind feet in the white rhinoceros (Ceratotherium simum).

PubMed

Dudley, Robert J; Wood, Simon P; Hutchinson, John R; Weller, Renate

2015-01-01

Foot pathology is a common and important health concern in captive rhinoceroses worldwide, but osteopathologies are rarely diagnosed, partly because of a lack of radiographic protocols. Here, we aimed to develop the first radiographic protocol for rhinoceros feet and describe the radiographic anatomy of the white rhinoceros (Ceratotherium simum) hind foot (pes). Computed tomographic images were obtained of nine cadaver pedes from seven different white rhinoceroses and assessed for pathology. A single foot deemed free of pathology was radiographed using a range of different projections and exposures to determine the best protocol. 3D models were produced from the CT images and were displayed with the real radiographs to describe the normal radiographic anatomy of the white rhinoceros pes. An optimal radiographic projection was determined for each bone in the rhinoceros pes focusing on highlighting areas where pathology has been previously described. The projections deemed to be most useful were D60Pr-PlDiO (digit III), D45Pr45M-PlDiLO (digit II), and D40Pr35L-PlDiLO (digit IV). The primary beam was centered 5-7 cm proximal to the cuticle on the digit of interest. Articular surfaces, ridges, grooves, tubercles, processes and fossae were identified. The radiographic protocol we have developed along with the normal radiographic anatomy we have described will allow for more accessible and effective diagnosis of white rhinoceros foot osteopathologies. © 2014 American College of Veterinary Radiology.

Computation of molecular vibrational frequencies using anomalous harmoniclike potentials.

PubMed

Li, Xiangzhu; Paldus, Josef

2009-07-28

The instabilities of Hartree-Fock (HF) solutions at or near the equilibrium geometry of symmetric molecular species imply the existence of broken-symmetry solutions having a lower energy than the corresponding symmetry-adapted ones. Moreover, the distortion of the nuclear framework along the normal modes that are implied by such broken-symmetry solutions results in an anomalous or even singular behavior in the corresponding cuts of the potential energy surface (PES). Using such HF solutions as a reference, these anomalies propagate to a post-HF level and make it impossible to determine reliable harmonic or fundamental vibrational frequencies for such modes by relying on either numerical or analytical differentiation of the PES, requiring instead a numerical integration of the Schrodinger equation for the nuclear motion. This, in turn, requires a detailed knowledge on the PES in a wide range of geometries, necessitating a computation of the potential energy function in a large number of points. We present an alternative approach to this problem, referred to as the integral averaging method (IAM), which facilitates this task by significantly reducing the number of geometries for which one has to compute the potential energy while yielding results of practically the same accuracy as the solution of the Schrodinger equation. The IAM is applied to several ABA-type triatomics and to the allyl radical, whose asymmetric stretching mode potential suffers from an anomalous behavior due to the spin-preserving instabilities in restricted open-shell HF solutions.

Angular distributions for the F+H2-->HF+H reaction: The role of the F spin-orbit excited state and comparison with molecular beam experiments

NASA Astrophysics Data System (ADS)

Tzeng, Yi-Ren; Alexander, Millard H.

2004-09-01

We report quantum mechanical calculations of center-of-mass differential cross sections (DCS) for the F+H2→HF+H reaction performed on the multistate [Alexander-Stark-Werner (ASW)] potential energy surfaces (PES) that describe the open-shell character of this reaction. For comparison, we repeat single-state calculations with the Stark-Werner (SW) and Hartke-Stark-Werner (HSW) PESs. The ASW DCSs differ from those predicted for the SW and HSW PES in the backward direction. These differences arise from nonadiabatic coupling between several electronic states. The DCSs are then used in forward simulations of the laboratory-frame angular distributions (ADs) measured by Lee, Neumark, and co-workers [J. Chem. Phys. 82, 3045 (1985)]. The simulations are scaled to match experiment over the range 12°<Θlab<80°. As a natural consequence of the reduced backward scattering, the ASW ADs are more forward and sideways scattered than predicted by the HSW PES. At the two higher collision energies (2.74 and 3.42 kcal/mol) the enhanced sideways scattering of HF v'=2 products bring the ASW ADs in very good agreement with the experiment. At the lowest collision energy (1.84 kcal/mol), the simulations, for all three sets of PESs consistently underestimate the sideways scattering. The residual disagreements, particularly at the lowest collision energy, may be due to the known deficiencies in the PESs.

Computational Study of Field Initiated Surface Reactions for Synthesis of Diamond and Silicon

NASA Technical Reports Server (NTRS)

Musgrave, Charles Bruce

1999-01-01

This project involves using quantum chemistry to simulate surface chemical reactions in the presence of an electric field for nanofabrication of diamond and silicon. A field delivered by a scanning tunneling microscope (STM) to a nanometer scale region of a surface affects chemical reaction potential energy surfaces (PES) to direct atomic scale surface modification to fabricate sub-nanometer structures. Our original hypothesis is that the applied voltage polarizes the charge distribution of the valence electrons and that these distorted molecular orbitals can be manipulated with the STM so as to change the relative stabilities of the electronic configurations over the reaction coordinates and thus the topology of the PES and reaction kinetics. Our objective is to investigate the effect of applied bias on surface reactions and the extent to which STM delivered fields can be used to direct surface chemical reactions on an atomic scale on diamond and silicon. To analyze the fundamentals of field induced chemistry and to investigate the application of this technique for the fabrication of nanostructures, we have employed methods capable of accurately describing molecular electronic structure. The methods we employ are density functional theory (DFT) quantum chemical (QC) methods. To determine the effect of applied bias on surface reactions we have calculated the QC PESs in various applied external fields for various reaction steps for depositing or etching diamond and silicon. We have chosen reactions which are thought to play a role in etching and the chemical vapor deposition growth of Si and diamond. The PESs of the elementary reaction steps involved are then calculated under the applied fields, which we vary in magnitude and configuration. We pay special attention to the change in the reaction barriers, and transition state locations, and search for low energy reaction channels which were inaccessible without the applied bias.

F157. HIERARCHICAL PREDICTION ERRORS DURING AUDITORY MISMATCH UNDER PHARMACOLOGICAL MANIPULATIONS: A COMPUTATIONAL SINGLE-TRIAL EEG ANALYSIS

PubMed Central

Weber, Lilian; Diaconescu, Andreea; Tomiello, Sara; Schöbi, Dario; Iglesias, Sandra; Mathys, Christoph; Haker, Helene; Stefanics, Gabor; Schmidt, André; Kometer, Michael; Vollenweider, Franz X; Stephan, Klaas Enno

2018-01-01

Abstract Background A central theme of contemporary neuroscience is the notion that the brain embodies a generative model of its sensory inputs to infer on the underlying environmental causes, and that it uses hierarchical prediction errors (PEs) to continuously update this model. In two pharmacological EEG studies, we investigate trial-wise hierarchical PEs during the auditory mismatch negativity (MMN), an electrophysiological response to unexpected events, which depends on NMDA-receptor mediated plasticity and has repeatedly been shown to be reduced in schizophrenia. Methods Study1: Reanalysis of 64 channel EEG data from a previously published MMN study (Schmidt et al., 2012) using a placebo-controlled, within-subject design (N=19) to examine the effect of S-ketamine. Study2: 64 channel EEG data recorded during MMN (between subjects, double-blind, placebo-controlled design, N=73), to examine the effects of amisulpride and biperiden. Using the Hierarchical Gaussian Filter, a Bayesian learning model, we extracted trial-by-trial PE estimates on two hierarchical levels. These served as regressors in a GLM of trial-wise EEG signals at the sensor level. Results We find strong correlations of EEG with both PEs in both samples: lower-level PEs show effects early on (Study1: 133ms post-stimulus, Study2: 177ms), higher-level PEs later (Study1: 240ms, Study2: 450ms). The temporal order of these signatures thus mimics the hierarchical relationship of the PEs, as proposed by our computational model, where lower level beliefs need to be updated before learning can ensue on higher levels. Ketamine significantly reduced the representation of the higher-level PE in Study1. (Study2 has not been unblinded.) Discussion These studies present first evidence for hierarchical PEs during MMN and demonstrate that single-trial analyses guided by a computational model can distinguish different types (levels) of PEs, which are differentially linked to neuromodulators of demonstrated relevance for schizophrenia. Our analysis approach thus provides better mechanistic interpretability of pharmacological MMN studies, which will hopefully support the development of computational assays for diagnosis and treatment predictions in schizophrenia.

Incidence, mechanisms, predictors, and clinical impact of acute and late stent malapposition after primary intervention in patients with acute myocardial infarction: an intravascular ultrasound substudy of the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial.

PubMed

Guo, Ning; Maehara, Akiko; Mintz, Gary S; He, Yong; Xu, Kai; Wu, Xiaofan; Lansky, Alexandra J; Witzenbichler, Bernhard; Guagliumi, Giulio; Brodie, Bruce; Kellett, Mirle A; Dressler, Ovidiu; Parise, Helen; Mehran, Roxana; Stone, Gregg W

2010-09-14

The incidence and mechanisms of acute and late stent malapposition after primary stent implantation in ST-segment elevation myocardial infarction remain unclear. The Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial was a dual-arm, factorial, randomized trial comparing paclitaxel-eluting stents (PES) and otherwise equivalent bare metal stents (BMS) in ST-segment elevation myocardial infarction patients. The intravascular ultrasound substudy enrolled 241 patients with 263 native coronary lesions (201 PES, 62 BMS) with baseline and 13-month follow-up imaging. Postintervention acute stent malapposition (ASM) occurred in 34.3% PES- and 40.3% BMS-treated lesions. Of these, 39.1% PES- and 40.0% BMS-treated lesions resolved at follow-up, especially within the stent body (66.7%); complete resolution was accompanied by a reduction in external elastic membrane area. An ASM area >1.2 mm(2) best separated persistent from resolved ASM. At follow-up, a higher frequency of late stent malapposition was detected in PES-treated lesions (46.8%) mainly because of more late acquired stent malapposition (30.8%) compared with BMS-treated lesions. Late acquired stent malapposition area correlated to the decrease of peri-stent plaque in the subset of lesions without positive remodeling and only to change in external elastic membrane in the group with positive remodeling. Independent predictors of late acquired stent malapposition were plaque/thrombus protrusion (odds ratio, 5.60; 95% confidence interval [CI], 2.32 to 13.54) and PES use (odds ratio, 6.32; 95% CI, 2.15 to 18.62). The incidence of ASM was similar in PES- and BMS-treated lesions, but late acquired stent malapposition was more common in PES-treated lesions. The reason for resolved ASM was negative remodeling, with larger ASM areas separating persistent from resolved ASM. Late acquired stent malapposition was due mainly to positive remodeling and plaque/thrombus resolution. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00433966.

Single-molecule resolution of protein dynamics on polymeric membrane surfaces: the roles of spatial and population heterogeneity.

PubMed

Langdon, Blake B; Mirhossaini, Roya B; Mabry, Joshua N; Sriram, Indira; Lajmi, Ajay; Zhang, Yanxia; Rojas, Orlando J; Schwartz, Daniel K

2015-02-18

Although polymeric membranes are widely used in the purification of protein pharmaceuticals, interactions between biomolecules and membrane surfaces can lead to reduced membrane performance and damage to the product. In this study, single-molecule fluorescence microscopy provided direct observation of bovine serum albumin (BSA) and human monoclonal antibody (IgG) dynamics at the interface between aqueous buffer and polymeric membrane materials including regenerated cellulose and unmodified poly(ether sulfone) (PES) blended with either polyvinylpyrrolidone (PVP), polyvinyl acetate-co-polyvinylpyrrolidone (PVAc-PVP), or polyethylene glycol methacrylate (PEGM) before casting. These polymer surfaces were compared with model surfaces composed of hydrophilic bare fused silica and hydrophobic trimethylsilane-coated fused silica. At extremely dilute protein concentrations (10(-3)-10(-7) mg/mL), protein surface exchange was highly dynamic with protein monomers desorbing from the surface within ∼1 s after adsorption. Protein oligomers (e.g., nonspecific dimers, trimers, or larger aggregates), although less common, remained on the surface for 5 times longer than monomers. Using newly developed super-resolution methods, we could localize adsorption sites with ∼50 nm resolution and quantify the spatial heterogeneity of the various surfaces. On a small anomalous subset of the adsorption sites, proteins adsorbed preferentially and tended to reside for significantly longer times (i.e., on "strong" sites). Proteins resided for shorter times overall on surfaces that were more homogeneous and exhibited fewer strong sites (e.g., PVAc-PVP/PES). We propose that strong surface sites may nucleate protein aggregation, initiated preferentially by protein oligomers, and accelerate ultrafiltration membrane fouling. At high protein concentrations (0.3-1.0 mg/mL), fewer strong adsorption sites were observed, and surface residence times were reduced. This suggests that at high concentrations, adsorbed proteins block strong sites from further protein adsorption. Importantly, this demonstrates that strong binding sites can be modified by changing solution conditions. Membrane surfaces are intrinsically heterogeneous; by employing single-molecule techniques, we have provided a new framework for understanding protein interactions with such surfaces.

Model studies of hydrogen atom addition and abstraction processes involving ortho-, meta-, and para-benzynes.

PubMed

Clark, A E; Davidson, E R

2001-10-31

H-atom addition and abstraction processes involving ortho-, meta-, and para-benzyne have been investigated by multiconfigurational self-consistent field methods. The H(A) + H(B)...H(C) reaction (where r(BC) is adjusted to mimic the appropriate singlet-triplet energy gap) is shown to effectively model H-atom addition to benzyne. The doublet multiconfiguration wave functions are shown to mix the "singlet" and "triplet" valence bond structures of H(B)...H(C) along the reaction coordinate; however, the extent of mixing is dependent on the singlet-triplet energy gap (DeltaE(ST)) of the H(B)...H(C) diradical. Early in the reaction, the ground-state wave function is essentially the "singlet" VB function, yet it gains significant "triplet" VB character along the reaction coordinate that allows H(A)-H(B) bond formation. Conversely, the wave function of the first excited state is predominantly the "triplet" VB configuration early in the reaction coordinate, but gains "singlet" VB character when the H-atom is close to a radical center. As a result, the potential energy surface (PES) for H-atom addition to triplet H(B)...H(C) diradical is repulsive! The H3 model predicts, in agreement with the actual calculations on benzyne, that the singlet diradical electrons are not coupled strongly enough to give rise to an activation barrier associated with C-H bond formation. Moreover, this model predicts that the PES for H-atom addition to triplet benzyne will be characterized by a repulsive curve early in the reaction coordinate, followed by a potential avoided crossing with the (pi)1(sigma*)1 state of the phenyl radical. In contrast to H-atom addition, large activation barriers characterize the abstraction process in both the singlet ground state and first triplet state. In the ground state, this barrier results from the weakly avoided crossing of the dominant VB configurations in the ground-state singlet (S0) and first excited singlet (S1) because of the large energy gap between S0 and S1 early in the reaction coordinate. Because the S1 state is best described as the combination of the triplet X-H bond and the triplet H(B)...H(C) spin couplings, the activation barrier along the S0 abstraction PES will have much less dependence on the DeltaE(ST) of H(B)...H(C) than previously speculated. For similar reasons, the T1 potential surface is quite comparable to the S0 PES.

Temporal Prediction Errors Affect Short-Term Memory Scanning Response Time.

PubMed

Limongi, Roberto; Silva, Angélica M

2016-11-01

The Sternberg short-term memory scanning task has been used to unveil cognitive operations involved in time perception. Participants produce time intervals during the task, and the researcher explores how task performance affects interval production - where time estimation error is the dependent variable of interest. The perspective of predictive behavior regards time estimation error as a temporal prediction error (PE), an independent variable that controls cognition, behavior, and learning. Based on this perspective, we investigated whether temporal PEs affect short-term memory scanning. Participants performed temporal predictions while they maintained information in memory. Model inference revealed that PEs affected memory scanning response time independently of the memory-set size effect. We discuss the results within the context of formal and mechanistic models of short-term memory scanning and predictive coding, a Bayes-based theory of brain function. We state the hypothesis that our finding could be associated with weak frontostriatal connections and weak striatal activity.

Optical detection of blade flutter. [in YF-100 turbofan engine

NASA Technical Reports Server (NTRS)

Nieberding, W. C.; Pollack, J. L.

1977-01-01

The paper examines the capabilities of photoelectric scanning (PES) and stroboscopic imagery (SI) as optical monitoring tools for detection of the onset of flutter in the fan blades of an aircraft gas turbine engine. Both optical techniques give visual data in real time as well as video-tape records. PES is shown to be an ideal flutter monitor, since a single cathode ray tube displays the behavior of all the blades in a stage simultaneously. Operation of the SI system continuously while searching for a flutter condition imposes severe demands on the flash tube and affects its reliability, thus limiting its use as a flutter monitor. A better method of operation is to search for flutter with the PES and limit the use of SI to those times when the PES indicates interesting blade activity.

Intestinal surfactant permeation enhancers and their interaction with enterocyte cell membranes in a mucosal explant system.

PubMed

Danielsen, E Michael; Hansen, Gert H

2017-07-03

Intestinal permeation enhancers (PEs) are agents aimed to improve oral delivery of therapeutic drugs with poor bioavailability. The main permeability barrier for oral delivery is the intestinal epithelium, and PEs act to increase the paracellular and/or transcellular passage of drugs. Transcellular passage can be achieved by cell membrane permeabilization and/or by endocytic uptake and subsequent transcytosis. One broad class of PEs is surfactants which act by inserting into the cell membrane, thereby perturbing its integrity, but little is known about how the dynamics of the membrane are affected. In the present work, the interaction of the surfactants lauroyl-L-carnitine, 1-decanoyl-rac-glycerol, and nonaethylene glycol monododecyl ether with the intestinal epithelium was studied in organ cultured pig jejunal mucosal explants. As expected, at 2 mM, these agents rapidly permeabilized the enterocytes for the fluorescent polar tracer lucifer yellow, but surprisingly, they all also blocked both constitutive -and receptor-mediated pathways of endocytosis from the brush border, indicating a complete arrest of apical membrane trafficking. At the ultrastructural level, the PEs caused longitudinal fusion of brush border microvilli. Such a membrane fusogenic activity could also explain the observed formation of vesicle-like structures and large vacuoles along the lateral cell membranes of the enterocytes induced by the PEs. We conclude that the surfactant action of the PEs selected in this study not only permeabilized the enterocytes, but profoundly changed the dynamic properties of their constituent cell membranes.

Unexpected metal-insulator transition in thick Ca1-xSrxVO3 film on SrTiO3 (100) single crystal

NASA Astrophysics Data System (ADS)

Takayanagi, Makoto; Tsuchiya, Takashi; Namiki, Wataru; Ueda, Shigenori; Minohara, Makoto; Horiba, Koji; Kumigashira, Hiroshi; Terabe, Kazuya; Higuchi, Tohru

2018-03-01

Epitaxial Ca1-xSrxVO3 (0 ≦ x ≦ 1) thin films were grown on (100)-oriented SrTiO3 substrates by using the pulsed laser deposition technique. In contrast to the previous report that metal-insulator transition (MIT) in Ca1-xSrxVO3 (CSVO) was achieved only for extremely thin films (several nm thick), MIT was observed at 39, 72, and 113 K for films with a thickness of 50 nm. The electronic structure was investigated by hard and soft X-ray photoemission spectroscopy (HX-PES and SX-PES). The difference between these PES results was significant due to the variation in an escape depth of photoelectrons of PES. While HX-PES showed that the V 2p3/2 spectra consisted of four peaks (V5+, V4+, V3+, and V2+/1+), SX-PES showed only three peaks (V5+, V4+, and V3+). This difference can be caused by a strain from the substrate, which leads to the chemical disorder (V5+, V4+, V3+, and V2+/1+). The thin film near the substrate is affected by the strain. The positive magnetoresistance is attributed to the effect of electron-electron interactions in the disorder system. Therefore, the emergence of MIT can be explained by the electron-electron interactions from the chemical disorder due to the strain.

Mental health pharmacists as interim prescribers

PubMed Central

2017-01-01

Introduction: Turnover leading to fluctuations in prescriber availability presents many challenges, most notably in access to and continuity of care. In 2015, the Veterans Affairs Eastern Colorado Healthcare System (VA ECHCS) experienced a period of significant mental health prescriber turnover leading to patient utilization of psychiatric emergency services (PES) for nonemergent medication management. The resulting increase in volume placed excessive stress on PES prescribers. Mental health pharmacists have opportunities to provide interim medication management while patients are between prescribers. Methods: This study was a retrospective, cohort study of patients unassigned to an outpatient mental health prescriber due to prescriber turnover, receiving care at VA ECHCS between October 1, 2015, and February 28, 2016. The primary outcome was the number of pharmacist interventions performed. Secondary outcomes characterize the interventions performed and describe the change in the mean monthly volume of patients presenting to PES. Results: In this veteran population, 152 interventions were performed in 81 unique patients. The most common intervention was prescription renewals (80%). Interventions most commonly involved antidepressants (28%), antipsychotics (10%), and mood stabilizers (10%). Before initiation of the clinic, Denver VA PES experienced a mean of 300 monthly visits. After clinic implementation, PES visits decreased significantly to a mean of 237 visits per month (P = .041). Discussion: The pharmacist interim prescriber clinic was associated with a significant decrease in mean number of patients seen per month in PES. The success of the clinic also contributed to interest by the mental health service to expand clinical pharmacy services.

Medial Longitudinal Arch Angle Presents Significant Differences Between Foot Types: A Biplane Fluoroscopy Study.

PubMed

Balsdon, Megan E R; Bushey, Kristen M; Dombroski, Colin E; LeBel, Marie-Eve; Jenkyn, Thomas R

2016-10-01

The structure of the medial longitudinal arch (MLA) affects the foot's overall function and its ability to dissipate plantar pressure forces. Previous research on the MLA includes measuring the calcaneal-first metatarsal angle using a static sagittal plane radiograph, a dynamic height-to-length ratio using marker clusters with a multisegment foot model, and a contained angle using single point markers with a multisegment foot model. The objective of this study was to use biplane fluoroscopy to measure a contained MLA angle between foot types: pes planus (low arch), pes cavus (high arch), and normal arch. Fifteen participants completed the study, five from each foot type. Markerless fluoroscopic radiostereometric analysis (fRSA) was used with a three-dimensional model of the foot bones and manually matching those bones to a pair of two-dimensional radiographic images during midstance of gait. Statistically significant differences were found between barefoot arch angles of the normal and pes cavus foot types (p = 0.036), as well as between the pes cavus and pes planus foot types (p = 0.004). Dynamic walking also resulted in a statistically significant finding compared to the static standing trials (p = 0.014). These results support the classification of individuals following a physical assessment by a foot specialist for those with pes cavus and planus foot types. The differences between static and dynamic kinematic measurements were also supported using this novel method.

Associations of cannabis and cigarette use with psychotic experiences at age 18: findings from the Avon Longitudinal Study of Parents and Children.

PubMed

Gage, S H; Hickman, M; Heron, J; Munafò, M R; Lewis, G; Macleod, J; Zammit, S

2014-12-01

A clearer understanding of the basis for the association between cannabis use and psychotic experiences (PEs) is required. Our aim was to examine the extent to which associations between cannabis and cigarette use and PEs are due to confounding. A cohort study of 1756 adolescents with data on cannabis use, cigarette use and PEs. Cannabis use and cigarette use at age 16 were both associated, to a similar degree, with PEs at age 18 [odds ratio (OR) 1.48, 95% confidence interval (CI) 1.18-1.86 for cannabis and OR 1.61, 95% CI 1.31-1.98 for cigarettes]. Adjustment for cigarette smoking frequency (OR 1.27, 95% CI 0.91-1.76) or other illicit drug use (OR 1.25, 95% CI 0.91-1.73) substantially attenuated the relationship between cannabis and PEs. The attenuation was to a lesser degree when cannabis use was adjusted for in the cigarette PE association (OR 1.42, 95% CI 1.05-1.92). However, almost all of the participants used cannabis with tobacco, including those who classed themselves as non-cigarette smokers. Teasing out the effects of cannabis from tobacco is highly complex and may not have been dealt with adequately in studies to date, including this one. Complementary methods are required to robustly examine the independent effects of cannabis, tobacco and other illicit drugs on PEs.

Decontamination of materials contaminated with Francisella philomiragia or MS2 bacteriophage using PES-Solid, a solid source of peracetic acid.

PubMed

Buhr, T L; Young, A A; Johnson, C A; Minter, Z A; Wells, C M

2014-08-01

The aim of the study was to develop test methods and evaluate survival of Francisella philomiragia cells and MS2 bacteriophage after exposure to PES-Solid (a solid source of peracetic acid) formulations with or without surfactants. Francisella philomiragia cells (≥7·6 log10 CFU) or MS2 bacteriophage (≥6·8 log10 PFU) were deposited on seven different test materials and treated with three different PES-Solid formulations, three different preneutralized samples and filter controls at room temperature for 15 min. There were 0-1·3 log10 CFU (<20 cells) of cell survival, or 0-1·7 log10 (<51 PFU) of bacteriophage survival in all 21 test combinations (organism, formulation and substrate) containing reactive PES-Solid. In addition, the microemulsion (Dahlgren Surfactant System) showed ≤2 log10 (100 cells) of viable F. philomiragia cells, indicating the microemulsion achieved <2 log10 CFU on its own. Three PES-Solid formulations and one microemulsion system (DSS) inactivated F. philomiragia cells and/or MS2 bacteriophage that were deposited on seven different materials. A test method was developed to show that reactive PES-Solid formulations and a microemulsion system (DSS) inactivated >6 log10 CFU/PFU F. philomiragia cells and/or MS2 bacteriophage on different materials. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Surface patterning of polymeric separation membranes and its influence on the filtration performance

NASA Astrophysics Data System (ADS)

Maruf, Sajjad

Polymeric membrane based separation technologies are crucial for addressing the global issues such as water purification. However, continuous operations of these processes are often hindered by fouling which increases mass transport resistance of the membrane to permeation and thus the energy cost, and eventually replacement of the membrane in the system. In comparison to other anti-fouling strategies, the use of controlled surface topography to mitigate fouling has not been realized mainly due to the lack of methods to create targeted topography on the porous membrane surface. This thesis aims to develop a new methodology to create surface-patterned polymeric separation membrane to improve their anti-fouling characteristics during filtration. First, successful fabrication of sub-micron surface patterns directly on a commercial ultrafiltration (UF) membrane surface using nanoimprint lithographic (NIL) technique was demonstrated. Comprehensive filtration studies revealed that the presence of these sub-micron surface patterns mitigates not only the onset of colloidal particle deposition, but also lowers the rate of growth of cake layer after initial deposition, in comparison with un-patterned membranes. The anti-fouling effects were also observed for model protein solutions. Staged filtration experiments, with backwash cleaning, revealed that the permeate flux of the patterned membrane after protein fouling was considerably higher than that of the pristine or un-patterned membrane. In addition to the surface-patterning of UF membranes, successful fabrication of a surface-patterned thin film composite (TFC) membrane was shown for the first time. A two-step fabrication process was carried out by (1) nanoimprinting a polyethersulfone (PES) support using NIL, and (2) forming a thin dense film atop the PES support via interfacial polymerization (IP). Fouling experiments suggest that the surface patterns alter the hydrodynamics at the membrane-feed interface, which is effective in decreasing fouling in dead end filtration system. In summary, this thesis represents the first ever fabrication of functional patterned polymeric separation membrane and systematic investigation of the influence of submicron surface patterns on pressure-driven liquid membrane separations. The results presented here will enable an effective non-chemical surface modification anti-fouling strategy, which can be directly added onto current commercial separation membrane manufacturing route.

Physical education and sport in schools: a review of benefits and outcomes.

PubMed

Bailey, Richard

2006-10-01

This paper explores the scientific evidence that has been gathered on the contributions and benefits of physical education and sport (PES) in schools for both children and for educational systems. Research evidence is presented in terms of children's development in a number of domains: physical, lifestyle, affective, social, and cognitive. The review suggests that PES have the potential to make significant and distinctive contributions to development in each of these domains. It is suggested that PES have the potential to make distinctive contributions to the development of children's fundamental movement skills and physical competences, which are necessary precursors of participation in later lifestyle and sporting physical activities. They also, when appropriately presented, can support the development of social skills and social behaviors, self-esteem and proschool attitudes, and, in certain circumstances, academic and cognitive development. The review also stresses that many of these benefits will not necessarily result from participation, per se; the effects are likely to be mediated by the nature of the interactions between students and their teachers, parents, and coaches who work with them. Contexts that emphasize positive experiences, characterized by enjoyment, diversity, and the engagement of all, and that are managed by committed and trained teachers and coaches, and supportive and informed parents, significantly influence the character of these physical activities and increase the likelihood of realizing the potential benefits of participation.

Electronic structure of LiCoO2 thin films: A combined photoemission spectroscopy and density functional theory study

NASA Astrophysics Data System (ADS)

Ensling, David; Thissen, Andreas; Laubach, Stefan; Schmidt, Peter C.; Jaegermann, Wolfram

2010-11-01

The electronic properties of LiCoO2 have been studied by theoretical band-structure calculations (using density functional theory) and experimental methods (photoemission). Synchrotron-induced photoelectron spectroscopy, resonant photoemission spectroscopy (ResPES), and soft x-ray absorption (XAS) have been applied to investigate the electronic structure of both occupied and unoccupied states. High-quality PES spectra were obtained from stoichiometric and highly crystalline LiCoO2 thin films deposited “in situ” by rf magnetron sputtering. An experimental approach of separating oxygen- and cobalt-derived (final) states by ResPES in the valence-band region is presented. The procedure takes advantage of an antiresonant behavior of cobalt-derived states at the 3p-3d excitation threshold. Information about the unoccupied density of states has been obtained by OK XAS. The structure of the CoL absorption edge is compared to semiempirical charge-transfer multiplet calculations. The experimental results are furthermore compared with band-structure calculations considering three different exchange potentials [generalized gradient approximation (GGA), using a nonlocal Hubbard U (GGA+U) and using a hybrid functional (Becke, three-parameter, Lee-Yang-Parr [B3LYP])]. For these different approaches total density of states and partial valence-band density of states have been investigated. The best qualitative agreement with experimental results has been obtained by using a GGA+U functional with U=2.9eV .

Job Placement Regimes in Europe: Trends and Impacts of Changes. IAB Labour Market Research Topics.

ERIC Educational Resources Information Center

Konle-Seidl, Regina; Walwei, Ulrich

Trends in job placement in Europe and the effects of advances in information and communication technologies on job placement practices were examined through case studies of France, Germany, the Netherlands, and the United Kingdom. The case studies revealed that the market shares of public employment services (PES) are generally higher than those…

Safety concerns over the use of intestinal permeation enhancers: A mini-review.

PubMed

McCartney, Fiona; Gleeson, John P; Brayden, David J

2016-01-01

Intestinal permeation enhancers (PEs) are key components in ∼12 oral peptide formulations in clinical trials for a range of molecules, primarily insulin and glucagon-like-peptide 1 (GLP-1) analogs. The main PEs comprise medium chain fatty acid-based systems (sodium caprate, sodium caprylate, and N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC)), bile salts, acyl carnitines, and EDTA. Their mechanism of action is complex with subtle differences between the different molecules. With the exception of SNAC and EDTA, most PEs fluidize the plasma membrane causing plasma membrane perturbation, as well as enzymatic and intracellular mediator changes that lead to alteration of intestinal epithelial tight junction protein expression. The question arises as to whether PEs can cause irreversible epithelial damage and tight junction openings sufficient to permit co-absorption of payloads with bystander pathogens, lipopolysaccharides and its fragment, or exo- and endotoxins that may be associated with sepsis, inflammation and autoimmune conditions. Most PEs seem to cause membrane perturbation to varying extents that is rapidly reversible, and overall evidence of pathogen co-absorption is generally lacking. It is unknown however, whether the intestinal epithelial damage-repair cycle is sustained during repeat-dosing regimens for chronic therapy.

Experimental evaluation of wall Mach number distributions of the octagonal test section proposed for NASA Lewis Research Center's altitude wind tunnel

NASA Technical Reports Server (NTRS)

Harrington, Douglas E.; Burley, Richard R.; Corban, Robert R.

1986-01-01

Wall Mach number distributions were determined over a range of test-section free-stream Mach numbers from 0.2 to 0.92. The test section was slotted and had a nominal porosity of 11 percent. Reentry flaps located at the test-section exit were varied from 0 (fully closed) to 9 (fully open) degrees. Flow was bled through the test-section slots by means of a plenum evacuation system (PES) and varied from 0 to 3 percent of tunnel flow. Variations in reentry flap angle or PES flow rate had little or no effect on the Mach number distributions in the first 70 percent of the test section. However, in the aft region of the test section, flap angle and PES flow rate had a major impact on the Mach number distributions. Optimum PES flow rates were nominally 2 to 2.5 percent wtih the flaps fully closed and less than 1 percent when the flaps were fully open. The standard deviation of the test-section wall Mach numbers at the optimum PES flow rates was 0.003 or less.

Diagnostic Pitfalls of Discriminating Lymphoma-Associated Effusions

PubMed Central

Chen, Hung-Jen; Huang, Kuo-Yang; Tseng, Guan-Chin; Chen, Li-Hsiou; Bai, Li-Yuan; Liang, Shinn-Jye; Tu, Chih-Yen; Light, Richard W.

2015-01-01

Abstract High serum lactate dehydrogenase (LDH) level, immunologic defects, enlarged mediastinal lymph nodes, and frequent hydration and diuresis in lymphoma patients may affect the development of pleural effusion (PE). The study was to assess the clinical utility of “Light criteria” and the “recommended algorithm for investigating PEs” in patients with lymphoma. The characteristics of 126 PEs of lymphoma patients who underwent diagnostic thoracentesis between January 1, 2003, and April 30, 2012, were reviewed. Using Light criteria, 29 (23%) PEs were incorrectly classified. The sensitivity for exudates in Light criteria was 88% and the specificity was only 44%. In 32 transudates, PE LDH correlated with blood LDH concentration (P < 0.001, r = 0.66). Nine transudates were misclassified as exudates (50%; 9/18) just due to PE LDH more than two-thirds the upper limits. Among the 56 bilateral PEs, 33 (59%) were exudates. Ten (63%) polymorphonuclear (PMN)-predominant exudative PEs were malignant. Infective PEs were often mononuclear (67%) rather than PMN predominant. When a patient has lymphoma with either unilateral or bilateral PE, thoracentesis for microbiological testing and cytology is imperative. Carefully clinical correlation in addition to the result from Light criteria and differential cell count is essential for prompt management. PMID:25929933

Biological Interactions of Nanomaterials

DTIC Science & Technology

2008-12-01

reagent contains the tetrazolium compound MTS and an electron coupling reagent ( phenazine ethosulfate; PES). The quantity of formazan product as...PES Phenazine ethosulfate PS Polysaccharide RET Rearranged during transfection ROS Reactive oxygen species SD Standard deviation SEM Scanning

The development of photoemission spectroscopy and its application to the study of semiconductor interfaces Observations on the interplay between basic and applied research (Welch Memorial Lecture)

NASA Technical Reports Server (NTRS)

Spicer, W. E.

1985-01-01

A sketch is given of the development of photoemission electron spectroscopy (PES) with emphasis on the author's own experience. Emphasis is placed: (1) on the period between 1958-1970; (2) on the various developments which were required for PES to emerge; and (3) on the strong interactions between applied/fundamental and knowledge/empirically based research. A more detailed discussion is given of the recent (1975-present) application of PES to study the interfaces of III-V semiconductors.

[Application of injection test in confirming the ideal position of esophageal balloon catheter].

PubMed

Chen, Han; Xu, Ming; Yang, Yanlin; He, Xuan; Zhou, Jianxin

2017-09-01

To evaluate the safety and feasibility of injection test which is used to locate esophageal balloon catheter. A prospective study was conducted. The patients undergoing invasive mechanical ventilation (MV) admitted to general intensive care unit (ICU) of Beijing Tiantan Hospital Affiliated to Capital Medical University from May 2015 and March 2017 were enrolled. The commercially available esophageal balloon catheter was modified to perform injection test. The catheter was withdrawn step by step and the injection test was repeated until the presence disturbance wave presented, which indicated that the balloon had just entered the esophagus. The position where disturbance wave appears was named 0 cm. End-expiratory occlusions were performed at the positions of +15, +10, +5, 0, -5, -10 and -15 cm, respectively, and the changes of esophageal pressure (Pes) and airway pressures (Paw) were measured in the spontaneous breathing and passive ventilation, and the ratio between the changes (ΔPes/ΔPaw) was calculated. A total of 20 patients were enrolled, of which 15 patients finished both the spontaneous and the passive ventilation parts, and 2 patients finished only the spontaneous part and 3 patients finished only passive part. (1) Disturbance waves could be induced by injection test in all patients. The average depth of disturbance wave in spontaneous breathing was deeper than that in passive ventilation (cm: 42.4±3.8 vs. 41.8±3.3), but there was no significant difference between the two ventilation settings (P = 0.132). No adverse events occurred during the study period. (2) Pes increased with the stepwise withdraw of esophageal catheter, reached the maximal value at +5 cm, and then decreased when the catheter was further withdrawn, no matter in the spontaneous or the passive ventilation. In spontaneous breathing, the ΔPes/ΔPaw was within the ideal range (0.8-1.2) at the positions of 0, -5 and -10 cm. The ΔPes/ΔPaw was closest to unity at the positions of 0 cm (0.98±0.15). The ΔPes/ΔPaw at -15 cm (0.66±0.26) was significantly lower than that at 0 cm (P < 0.05). For passive ventilation, the ΔPes/ΔPaw was within the ideal range at the positions of -5 cm and -10 cm, and the ΔPes/ΔPaw was closest to unity at the positions of -10 cm (0.94±0.12). The ΔPes/ΔPaw at 0 cm and -5 cm was significantly higher than that at -10 cm (1.43±0.31 and 1.12±0.14, respectively); while the ΔPes/ΔPaw at -15 cm (0.68±0.23) was significantly lower than that at -10 cm (all P < 0.01). Ideal position of the esophageal balloon catheter could be determined quickly and easily by using injection test. The method is safe and clinically feasible. Clinical Trials, NCT02446938.

Multi-Million Atom Molecular Dynamics Simulations of Shocked Materials

DTIC Science & Technology

2006-11-01

chose this system for two reasons: First, accurate and widely tested atomistic models are available (van Beest et. al., 1990; Yuan and Cormack...Surface (PES) We have identified a model of silica (van Beest et. al., 1990) that has been extensively tested and that predicts several polymorphic...states (Saika-Voivod et. al., 2004). This model, hereafter denoted as the BKS model after its authors (van Beest et. al., 1990), assumes that the

A Direct Mechanism of Ultrafast Intramolecular Singlet Fission in Pentacene Dimers

DTIC Science & Technology

2016-08-24

property for materials used in third- generation solar cells and photodetectors, among other optoelectronic devices.1−3 Unfortunately, techno- logical...detailed mechanism of iSF and to establish its relationship to chemical structure. Current literature on the mechanism of xSF is in general agreement...not been identified. We use this ring-breathing mode to generate a two- dimensional potential energy surface (PES) for the excited states along the

Surface engineered two-dimensional and quasi-one-dimensional nanomaterials for electronic and optoelectronic devices

NASA Astrophysics Data System (ADS)

Du, Xiang

As the sizes of individual components in electronic and optoelectronic devices approach nano scale, the performance of the devices is often determined by surface properties due to their large surface-to-volume ratio. Surface phenomena have become one of the cornerstones in nanoelectronic industry. For this reason, research on the surface functionalization has been tremendous amount of growth over the past decades, and promises to be an increasingly important field in the future. Surface functionalization, as an effective technique to modify the surface properties of a material through a physical or chemical approach, exhibits great potential to solve the problems and challenges, and modulate the performance of nanomaterials based functional devices. Surface functionalization drives the developments and applications of modern electronic and optoelectronic devices fabricated by nanomaterials. In this thesis, I demonstrate two surface functionalization approaches, namely, surface transfer doping and H2 annealing, to effectively solve the problems and significantly enhance the performance of 2D (single structure black phosphorus (BP) and heterostructure graphene/Si Schottky junction), and quasi-1D (molybdenum trioxide (MoO 3) nanobelt) nanomaterials based functional devices, respectively. In situ photoelectron spectroscopy (PES) measurements were also carried out to explore the interfacial charge transfer occurring at the interface between the nanostructures and doping layers, and the gap states in MoO 3 thin films, which provides the underlying mechanism to understand and support our device measurement results. In the first part of this thesis, I will discuss the first surface functionalization approach, namely, surface transfer doping, to effectively modulate the ambipolar characteristics of 2D few-layer BP flakes based FETs. The ambipolar characteristics of BP transistors were effectively modulated through in situ surface functionalization with cesium carbonate (Cs2CO3) and MoO3, respectively. Cs2CO3 was found to strongly electron dope black phosphorus. The electron mobility of black phosphorus was significantly enhanced to ˜27 cm2V-1s-1 after 10 nm Cs2CO3 modification, indicating a greatly improved electron transport behavior. In contrast, MoO3 decoration demonstrated a giant hole doping effect. In situ PES characterization confirms the interfacial charge transfer between black phosphorus and doping layers. This doping can also modulate the Schottky junctions formed between metal contacts and black phosphorus flakes, and hence to enhance the responsivity of black phosphorus based photodetectors. These findings coupled with the tunable nature of the surface transfer doping scheme ensure black phosphorus as a promising candidate for further complementary logic electronics. Following the same surface transfer doping technique, I will demonstrate a remarkable performance enhancement of graphene/Si Schottky junction based self-powered photodetectors via surface modification with MoO3 thin film. It was found that the photocurrent responsivity of MoO3 doped graphene/Si photodetectors was highly increased under a wide spectrum of illuminated light from ultraviolet to near infrared. The current on-off ratio reached up to ˜104 under illumination of 500 nm light with intensity of ˜62 muWcm-2. More importantly, the external quantum efficiency of graphene/Si devices was significantly enhanced up to ˜80% by almost four times in the visible light region after MoO3 functionalization. The largely improved photodetecting performance originates from the increased Schottky barrier height at the graphene/Si interface as well as the reduced series resistance after MoO3 modification, which was further corroborated by the in situ PES and electrical transport characterizations. These observations promise a simple method to effectively modify the graphene/Si Schottky junction based self-powered photodetectors and thus significantly enhance their photodetecting performance. After discussion of the first surface functionalization method, next I will introduce the second approach which is H2 annealing, to greatly extend the photoresponse range of single MoO3 nanobelt based photodetector from UV to visible light by introducing substantial gap states. After annealing, the conductance of MoO3 nanobelt was largely enhanced; at the same time, the photodetector possessed wide visible spectrum response. As corroborated by in situ PES investigations, such strong wide spectrum photoresponse arises from the largely enriched oxygen vacancies and gap states in MoO3 nanobelt after H2 annealing. These results open up a new avenue to extend the wide bandgap metal oxide nanomaterials based optoelectronics devices with efficient visible light response through surface modification, i.e. the introduction of the high density of carefully engineered gap states.

Research on the performance of the spastic calf muscle of young adults with cerebral palsy.

PubMed

Lampe, Renee; Mitternacht, Jurgen

2011-02-12

The aim of this study was to find an objective graduation of pes equinus in infantile cerebral palsy, especially with regard to functional aspects, to allow a differentiated choice of the therapeutic options. Very often raises the question of whether a surgical lengthening of the Achilles tendon may let expect a functional improvement. For this documentation 17 patients with pes equinus and a diagnosis of spastic cerebral palsy, primarily of the lower limbs, and hemiplegia were examined first clinically and then by a procedure for calculating the functional kinetic parameters from an in-shoe plantar pressure distribution measurement (novel pedar-X system), which is used in many orthopedic practices and clinics as a standard measuring device. Using additional video motion analysis, the flexion in the ankle joint and the ankle joint torque were determined. From this the physical performance of the spastically shortened calf muscle was calculated. The course of the curves of torque and joint performance allows a functional classification of the pes equinus. Approximately three quarters of all pes equinus demonstrated functional activity of the most part of the normal push-off propulsion power. Even the rigid pes equinus was capable of performing push-off propulsion work, provided it converted energy that was absorbed during the heel-strike phase and released it again during the push-off phase. This suggests that the function of paretic ankle joint is better than its kinematics of motion. A heel strike with a pes equinus triggers via stretching stimuli in the muscle-ligament structure reflex motor functions, thereby causing the typical spastic gait pattern. This remarkable gait pattern is often evaluated as dysfunctional and as absolutely requiring correction. However, an aspect possibly neglected in this instance is the fact that this gait pattern may be efficient for the patient and may in fact be a suitable means allowing for economic locomotion despite the cerebral control deficits. Pes equinus; Cerebral palsy; Pedography; Ankle joint performance.

An assessment of adherence to basic ecological principles by payments for ecosystem service projects.

PubMed

Prager, C M; Varga, A; Olmsted, P; Ingram, J C; Cattau, M; Freund, C; Wynn-Grant, R; Naeem, S

2016-08-01

Programs and projects employing payments for ecosystem service (PES) interventions achieve their objectives by linking buyers and sellers of ecosystem services. Although PES projects are popular conservation and development interventions, little is known about their adherence to basic ecological principles. We conducted a quantitative assessment of the degree to which a global set of PES projects adhered to four ecological principles that are basic scientific considerations for any project focused on ecosystem management: collection of baseline data, identification of threats to an ecosystem service, monitoring, and attention to ecosystem dynamics or the formation of an adaptive management plan. We evaluated 118 PES projects in three markets-biodiversity, carbon, and water-compiled using websites of major conservation organizations; ecology, economic, and climate-change databases; and three scholarly databases (ISI Web of Knowledge, Web of Science, and Google Scholar). To assess adherence to ecological principles, we constructed two scientific indices (one additive [ASI] and one multiplicative [MSI]) based on our four ecological criteria and analyzed index scores by relevant project characteristics (e.g., sector, buyer, seller). Carbon-sector projects had higher ASI values (P < 0.05) than water-sector projects and marginally higher ASI scores (P < 0.1) than biodiversity-sector projects, demonstrating their greater adherence to ecological principles. Projects financed by public-private partnerships had significantly higher ASI values than projects financed by governments (P < 0.05) and marginally higher ASI values than those funded by private entities (P < 0.1). We did not detect differences in adherence to ecological principles based on the inclusion of cobenefits, the spatial extent of a project, or the size of a project's budget. These findings suggest, at this critical phase in the rapid growth of PES projects, that fundamental ecological principles should be considered more carefully in PES project design and implementation in an effort to ensure PES project viability and sustainability. © 2015 Society for Conservation Biology.

Psychotic Experiences and Working Memory: A Population-Based Study Using Signal-Detection Analysis.

PubMed

Rossi, Rodolfo; Zammit, Stanley; Button, Katherine S; Munafò, Marcus R; Lewis, Glyn; David, Anthony S

2016-01-01

Psychotic Experiences (PEs) during adolescence index increased risk for psychotic disorders and schizophrenia in adult life. Working memory (WM) deficits are a core feature of these disorders. Our objective was to examine the relationship between PEs and WM in a general population sample of young people in a case control study. 4744 individuals of age 17-18 from Bristol and surrounding areas (UK) were analyzed in a cross-sectional study nested within the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort study. The dependent variable was PEs, assessed using the semi-structured Psychosis-Like Symptom Interview (PLIKSi). The independent variable was performance on a computerized numerical n-back working memory task. Signal-Detection Theory indices, including standardized hits rate, false alarms rate, discriminability index (d') and response bias (c) from 2-Back and 3-Back tasks were calculated. 3576 and 3527 individuals had complete data for 2-Back and 3-Back respectively. Suspected/definite PEs prevalence was 7.9% (N = 374). Strongest evidence of association was seen between PEs and false alarms on the 2-Back, (odds ratio (OR) = 1.17 [95% confidence intervals (CI) 1.01, 1.35]) and 3-back (OR = 1.35 [1.18, 1.54]) and with c (OR = 1.59 [1.09, 2.34]), and lower d' (OR = 0.76 [0.65, 0.89]), on the 3-Back. Adjustment for several potential confounders, including general IQ, drug exposure and different psycho-social factors, and subsequent multiple imputation of missing data did not materially alter the results. WM is impaired in young people with PEs in the general population. False alarms, rather than poor accuracy, are more closely related to PEs. Such impairment is consistent with different neuropsychological models of psychosis focusing on signal-to-noise discrimination, probabilistic reasoning and impaired reality monitoring as a basis of psychotic symptoms.

What Story Does Geographic Separation of Insular Bats Tell? A Case Study on Sardinian Rhinolophids

PubMed Central

Russo, Danilo; Di Febbraro, Mirko; Rebelo, Hugo; Mucedda, Mauro; Cistrone, Luca; Agnelli, Paolo; De Pasquale, Pier Paolo; Martinoli, Adriano; Scaravelli, Dino; Spilinga, Cristiano; Bosso, Luciano

2014-01-01

Competition may lead to changes in a species’ environmental niche in areas of sympatry and shifts in the niche of weaker competitors to occupy areas where stronger ones are rarer. Although mainland Mediterranean (Rhinolophus euryale) and Mehely’s (R. mehelyi) horseshoe bats mitigate competition by habitat partitioning, this may not be true on resource-limited systems such as islands. We hypothesize that Sardinian R. euryale (SAR) have a distinct ecological niche suited to persist in the south of Sardinia where R. mehelyi is rarer. Assuming that SAR originated from other Italian populations (PES) – mostly allopatric with R. mehelyi – once on Sardinia the former may have undergone niche displacement driven by R. mehelyi. Alternatively, its niche could have been inherited from a Maghrebian source population. We: a) generated Maxent Species Distribution Models (SDM) for Sardinian populations; b) calibrated a model with PES occurrences and projected it to Sardinia to see whether PES niche would increase R. euryale’s sympatry with R. mehelyi; and c) tested for niche similarity between R. mehelyi and PES, PES and SAR, and R. mehelyi and SAR. Finally we predicted R. euryale’s range in Northern Africa both in the present and during the Last Glacial Maximum (LGM) by calibrating SDMs respectively with SAR and PES occurrences and projecting them to the Maghreb. R. mehelyi and PES showed niche similarity potentially leading to competition. According to PES’ niche, R. euryale would show a larger sympatry with R. mehelyi on Sardinia than according to SAR niche. Such niches have null similarity. The current and LGM Maghrebian ranges of R. euryale were predicted to be wide according to SAR’s niche, negligible according to PES’ niche. SAR’s niche allows R. euryale to persist where R. mehelyi is rarer and competition probably mild. Possible explanations may be competition-driven niche displacement or Maghrebian origin. PMID:25340737

The effectiveness of non-surgical intervention (Foot Orthoses) for paediatric flexible pes planus: A systematic review: Update

PubMed Central

Uden, Hayley; Banwell, Helen A.; Kumar, Saravana

2018-01-01

Background Flexible pes planus (flat feet) in children is a common presenting condition in clinical practice due to concerns amongst parents and caregivers. While Foot Orthoses (FOs) are a popular intervention, their effectiveness remains unclear. Thus, the aim of this systematic review was to update the current evidence base for the effectiveness of FOs for paediatric flexible pes planus. Methods A systematic search of electronic databases (Cochrane, Medline, AMED, EMBASE, CINHAL, SportDiscus, Scopus and PEDro) was conducted from January 2011 to July 2017. Studies of children (0–18 years) diagnosed with flexible pes planus and intervention to be any type of Foot Orthoses (FOs) were included. This review was conducted and reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. McMaster critical review form for quantitative studies, was used to assess the methodological quality of the included studies. Given the heterogeneity of the included studies, a descriptive synthesis of the included studies was undertaken. Results Out of 606 articles identified, 11 studies (three RCTs; two case-controls; five case-series and one single case study) met the inclusion criteria. A diverse range of pre-fabricated and customised FOs were utilised and effectiveness measured through a plethora of outcomes. Summarised findings from the heterogeneous evidence base indicated that FOs may have a positive impact across a range of outcomes including pain, foot posture, gait, function and structural and kinetic measures. Despite these consistent positive outcomes reported in several studies, the current evidence base lacks clarity and uniformity in terms of diagnostic criteria, interventions delivered and outcomes measured for paediatric flexible pes planus. Conclusion There continues to remain uncertainty on the effectiveness of FOs for paediatric flexible pes planus. Despite a number of methodological limitations, FOs show potential as a treatment method for children with flexible pes planus. PROSPERO registration number CRD42017057310. PMID:29451921

Disruption of Retinol (Vitamin A) Signaling by Phthalate Esters: SAR and Mechanism Studies.

PubMed

Chen, Yanling; Reese, David H

2016-01-01

A spectrum of reproductive system anomalies (cryptorchidism, hypospadias, dysgenesis of Wolffian duct-derived tissues and prostate, and reduced sperm production) in male rats exposed in utero to phthalate esters (PEs) are thought to be caused by PE inhibition of fetal testosterone production. Recently, dibutyl and dipentyl phthalate (DBuP, DPnP) were shown to disrupt the retinol signaling pathway (RSP) in mouse pluripotent P19 embryonal carcinoma cells in vitro. The RSP regulates the synthesis and cellular levels of retinoic acid (RA), the active metabolite of retinol (vitamin A). In this new study, a total of 26 di- and mono-esters were screened to identify additional phthalate structures that disrupt the RSP and explore their mechanisms of action. The most potent PEs, those causing > 50% inhibition, contained aryl and cycloalkane groups or C4-C6 alkyl ester chains and were the same PEs reported to cause malformations in utero. They shared similar lipid solubility; logP values were between 4 and 6 and, except for PEs with butyl and phenyl groups, were stable for prolonged periods in culture. Mono- and cognate di-esters varied in ability to disrupt the RSP; e.g., DEHP was inactive but its monoester was active while DBuP was active yet its monoester was inactive. DBuP and dibenzyl phthalate both disrupted the synthesis of RA from retinol but not the ability of RA to activate gene transcription. Both PEs also disrupted the RSP in C3H10T1/2 multipotent mesenchymal stem cells. Based on this in vitro study showing that some PEs disrupt retinol signaling and previous in vivo studies that vitamin A/RA deficiency and PEs both cause strikingly similar anomalies in the male rat reproductive system, we propose that PE-mediated inhibition of testosterone and RA synthesis in utero are both causes of malformations in male rat offspring.

Esthetic evaluation of maxillary single-tooth implants in the esthetic zone

PubMed Central

Cho, Hae-Lyung; Lee, Jae-Kwan; Um, Heung-Sik

2010-01-01

Purpose The aim of this study is to assess the influence exerted by the observer's dental specialization and compare patients' opinion with observers' opinion of the esthetics of maxillary single-tooth implants in the esthetic zone. Methods Forty-one adult patients, who were treated with a single implant in the esthetic zone, were enrolled in this study. Eight observers (2 periodontists, 2 prosthodontists, 2 orthodontists and 2 senior dental students) applied the pink esthetic score (PES)/white esthetic score (WES) to 41 implant-supported single restorations twice with an interval of 4 weeks. We used a visual analog scale (VAS) to assess the patient's satisfaction with the treatment outcome from an esthetic point of view. Results In the PES/WES, very good and moderate intraobserver agreements were noted between the first and second rating. The mean total PES/WES was 11.19 ± 3.59. The mean PES was 5.17 ± 2.29 and mean WES was 6.02 ± 1.96. In the total PES/WES, the difference between the groups was not significant. However, in the WES, the difference between the groups was significant and prosthodontists were found to have assigned poorer ratings than the other groups. Periodontists gave higher ratings than prosthodontists and senior dental students. Orthodontists were clearly more critical than the other observers. The statistical analysis revealed statistically significant correlation between patients' esthetic perception and dentists' perception of the anterior tooth. However, the correlation between the total PES/WES and the VAS score for the first premolar was not statistically significant. Conclusions The PES/WES is an objective tool in rating the esthetics of implant supported single crowns and adjacent soft tissues. Orthodontists were the most critical observers, while periodontists were more generous than other observers. The statistical analysis revealed a statistically significant correlation between patients' esthetic perception and dentists' perception of the anterior tooth. PMID:20827328

Hybride ZnCdCrO embedded aminated polyethersulfone nanocomposites for the development of Hg2+ ionic sensor

NASA Astrophysics Data System (ADS)

Rahman, Mohammed M.; Alenazi, Noof A.; Hussein, Mahmoud A.; Alam, M. M.; Alamry, Khalid A.; Asiri, Abdullah M.

2018-06-01

In this current study, ‑NH2 functions are introduced on Polyethersulfone (PES) by a nitration reaction then a reduction reaction to fabricate PES-NH2 materials with a better hydrophilicity property. The structure of PES-NH2 was first confirmed using proton nuclear magnetic resonance spectroscopy (1H-NMR) and Fourier transform infrared (FT-IR) spectroscopy. Then, the resultant polymer was doped with different concentrations of ZnCdCrO nanocomposites. The polymeric nanocomposites materials were characterized using FT-IR, x-ray powder diffraction (XRD), thermal analysis (TA), and energy dispersive x-ray (EDX) spectroscopy while the morphology was investigated using scanning electron microscopy (SEM). The performance PES-NH2-ZnCdCrO nanocomposites was investigated by sensor-probe towards the selective detection of Hg2+. The results showed the excellent thermal properties of PES-NH2-ZnCdCrO nanocomposites in comparison with non-doped polymer (PES-NH2). Here, Hg2+ ionic sensor was prepared using a flat glassy carbon electrode (GCE) coated with a thin-layer of PES-NH2-ZnCdCrO nanocomposites (20%) with nafion conducting nafion binder (5%). To evaluate the analytical performances of Hg2+ ion sensor, a calibration curve was drawn by plotting the current versus concentration. The sensitivity (0.6566 μAμM-1 cm‑2) and detection limit (14.46 ± 0.72 pM) are calculated using the slope of the calibration curve. It was determined the linearity (r2 = 0.9941) over the large linear dynamic range (LDR) (0.1 nM to 0.1 mM). Thus, this research approach might be an important route to the selective detection of environmental toxin (Hg2+ cation) from the aqueous system in broad scales for the safety of health care, environmental, and aquatic fields.

Analysis of the vibronic structure of the trans-stilbene fluorescence and excitation spectra: the S0 and S1 PES along the Ce[double bond, length as m-dash]Ce and Ce-Cph torsions.

PubMed

Orlandi, Giorgio; Garavelli, Marco; Zerbetto, Francesco

2017-09-20

We analyze the highly resolved vibronic structure of the low energy (≤200 cm -1 ) region of the fluorescence and fluorescence excitation spectra of trans-stilbene in supersonic beams. In this spectral region the vibronic structure is associated mainly with vibrational levels of the C e -C e torsion (τ) and the a u combination of the two C e -C ph bond twisting (ϕ). We base this analysis on the well-established S 0 (τ, ϕ) two-dimensional potential energy surface (PES) and on a newly refined S 1 (τ, ϕ) PES. We obtain vibrational eigenvalues and eigenvectors of the anharmonic S 0 (τ, ϕ) and S 1 (τ, ϕ) PES using a numerical procedure based on the Meyer's flexible model [R. Meyer, J. Mol. Spectrosc., 1979, 76, 266]. Then we derive Franck-Condon factors and therefore intensities of the relevant vibronic bands for the S 0 → S 1 excitation and S 1 → S 0 fluorescence spectra. Furthermore, we assess the role of the b g combination of the two C e -C ph bond twisting (ν 48 ) in the structure of the S 1 → S 0 fluorescence spectra. By the use of these results we are able to assign most of the low energy vibrational levels of the S 0 → S 1 excitation spectra and of the fluorescence spectra of the emission from several low energy S 1 vibronic levels. The good agreement between the observed and the computed vibrational structure of the S 0 → S 1 and S 1 → S 0 spectra suggests that the proposed picture of the E 1 (τ, ϕ) and E 0 (τ, ϕ) PES, in particular along the coordinate τ governing trans-cis photo-isomerization in S 1 , is accurate. In S 0 , the barriers for the C e [double bond, length as m-dash]C e torsion and for the a u type C e -C ph bond twisting are 16 080 cm -1 and 3125 cm -1 , respectively, while in S 1 , where the bond orders of the C e [double bond, length as m-dash]C e and C e -C ph bonds are reversed, the two barriers become 1350 cm -1 and 8780 cm -1 , respectively.

Scaling participation in payments for ecosystem services programs

PubMed Central

Donlan, C. Josh; Boyle, Kevin J.; Xu, Weibin; Gelcich, Stefan

2018-01-01

Payments for ecosystem services programs have become common tools but most have failed to achieve wide-ranging conservation outcomes. The capacity for scale and impact increases when PES programs are designed through the lens of the potential participants, yet this has received little attention in research or practice. Our work with small-scale marine fisheries integrates the social science of PES programs and provides a framework for designing programs that focus a priori on scaling. In addition to payments, desirable non-monetary program attributes and ecological feedbacks attract a wider range of potential participants into PES programs, including those who have more negative attitudes and lower trust. Designing programs that draw individuals into participating in PES programs is likely the most strategic path to reaching scale. Research should engage in new models of participatory research to understand these dynamics and to design programs that explicitly integrate a broad range of needs, values, and modes of implementation. PMID:29522554

Harmonium: An Ultrafast Vacuum Ultraviolet Facility.

PubMed

Arrell, Christopher A; Ojeda, José; Longetti, Luca; Crepaldi, Alberto; Roth, Silvan; Gatti, Gianmarco; Clark, Andrew; van Mourik, Frank; Drabbels, Marcel; Grioni, Marco; Chergui, Majed

2017-05-31

Harmonium is a vacuum ultraviolet (VUV) photon source built within the Lausanne Centre for Ultrafast Science (LACUS). Utilising high harmonic generation, photons from 20-110 eV are available to conduct steady-state or ultrafast photoelectron and photoion spectroscopies (PES and PIS). A pulse preserving monochromator provides either high energy resolution (70 meV) or high temporal resolution (40 fs). Three endstations have been commissioned for: a) PES of liquids; b) angular resolved PES (ARPES) of solids and; c) coincidence PES and PIS of gas phase molecules or clusters. The source has several key advantages: high repetition rate (up to 15 kHz) and high photon flux (1011 photons per second at 38 eV). The capabilities of the facility complement the Swiss ultrafast and X-ray community (SwissFEL, SLS, NCCR MUST, etc.) helping to maintain Switzerland's leading role in ultrafast science in the world.

Payment for Environmental Services: Hypotheses and Evidence

PubMed Central

Alston, Lee J.; Andersson, Krister; Smith, Steven M.

2014-01-01

The use of payment for environmental services (PES) is not a new type of contract, but PES programs have become more in vogue because of the potential for sequestering carbon by paying to prevent deforestation and degradation of forestlands. We provide a framework utilizing transaction costs to hypothesize which services are more likely to be provided effectively. We then interpret the literature on PES programs to see the extent to which transaction costs vary as predicted across the type of service and to assess the performance of PES programs. As predicted, we find that transaction costs are the least for club goods like water and greatest for pure public goods like carbon reduction. Actual performance is difficult to measure and varies across the examples. More work and experimentation are needed to gain a better outlook on what elements support effective delivery of environmental services. PMID:25143798

Endotherapy for severe and complete pharyngo-esophageal post-radiation stenosis using wires, balloons and pharyngo-esophageal puncture (PEP) (with videos).

PubMed

Tang, Shou-jiang; Singh, Shailender; Truelson, John M

2010-01-01

Pharyngo-esophageal stenosis (PES) and upper esophageal stricture are common in patients who receive radiation therapy for laryngeal and hypopharyngeal cancers. In severe or complete stenosis, the patients generally have complete dysphagia with inability to swallow their saliva. Diagnostic and therapeutic esophagogastroduodenoscopy (EGD) plays an important role in investigating the dysphagia and in managing the underlying stenosis. We translate endoscopic retrograde cholangiopancreatography (ERCP) techniques and skills in approaching pancreaticobiliary obstruction in the management of severe and complete PES. We select and report three cases of severe or complete PES in which flexible endoscopic therapy was successfully provided by using fluoroscopy, ERCP wire guides, endoscopic balloons, and by performing pharyngo-esophageal puncture (PEP). We propose the term PEP in managing complete PES. We believe this approach can offer safety and efficiency with very high success rate.

Assessment of structured physical examination skills training using a retro-pre-questionnaire.

PubMed

Piryani, Rano Mal; Shankar, P Ravi; Piryani, Suneel; Thapa, Trilok Pati; Karki, Balmansingh; Khakurel, Mahesh Prasad; Bhandary, Shital

2013-01-01

The effectiveness of physical examination skills (PES) training is very rarely assessed using the "post-then-pre" approach. In this study, a retro-pre-questionnaire was used to study the effect of structured physical examination skills training (SPEST) imparted to second-year undergraduate medical students. KIST Medical College (KISTMC) affiliated to Tribhuvan University Nepal admitted its first batch of MBBS students in November 2008. The university curriculum recommends the involvement of Medicine and Surgery Departments in PES training, but the methods for teaching and assessment are not well defined. KISTMC has made training more structured and involved the Medicine, Surgery, Gynaecology and Obstetrics, Orthopaedics, ENT, Ophthalmology, Paediatrics, and Family Medicine Departments. SPEST includes the teaching/learning of basic PES for 210 minutes once a week for 28 weeks. Self-assessment is done by using a retro-pre-questionnaire at the end of the last session of training, and these data are analysed using SPSS. Out of 100 students, 98 participated in the objective structured clinical examination (OSCE); 82 completed the retro-pre-questionnaire. Forty-six skills representing various systems were selected for inclusion in the retro-pre-questionnaire from among the many skills taught in different departments. The average perceived skills score (maximum score, 46×4=184) before training was 15.9 and increased to 116.5 after training. The increase was statistically significant upon the application of a paired t-test. The students perceived that their level of skills improved after the training. The retro-pre- instrument seems to be useful for assessing the learners' self-reported changes in PES after training if a large number of skills need to be assessed. However, it should be noted that although a retro-pre-questionnaire may reveal valuable information, it is not a substitute for an objective measure or gold standard.

Effect of dialyzer membrane materials on survival in chronic hemodialysis patients: Results from the annual survey of the Japanese Nationwide Dialysis Registry

PubMed Central

Hamano, Takayuki; Wada, Atsushi; Nakai, Shigeru; Masakane, Ikuto

2017-01-01

Background Little information is available regarding which type of dialyzer membrane results in good prognosis in patients on chronic hemodialysis. Therefore, we conducted a cohort study from a nationwide registry of hemodialysis patients in Japan to establish the association between different dialyzer membranes and mortality rates. Methods We followed 142,412 patients on maintenance hemodialysis (female, 39.1%; mean age, 64.8 ± 12.3 years; median dialysis duration, 7 [4–12] years) for a year from 2008 to 2009. We included patients treated with seven types of high-flux dialyzer membranes at baseline, including cellulose triacetate (CTA), ethylene vinyl alcohol (EVAL), polyacrylonitrile (PAN), polyester polymer alloy (PEPA), polyethersulfone (PES), polymethylmethacrylate (PMMA), and polysulfone (PS). Cox regression was used to estimate the association between baseline dialyzers and all-cause mortality as hazard ratios (HRs) and 95% confidence intervals for 1-year mortality adjusting for potential confounders, and propensity score matching analysis was performed. Results The distribution of patients treated with each membrane was as follows: PS (56.0%), CTA (17.3%), PES (12.0%), PEPA (7.5%), PMMA (4.9%), PAN (1.2%), and EVAL (1.1%). When data were adjusted using basic factors, with PS as a reference group, the mortality rate was significantly higher in all groups except for the PES group. When data were further adjusted for dialysis-related factors, HRs were significantly higher for the CTA, EVAL, and PEPA groups. When the data were further adjusted for nutrition-and inflammation-related factors, HRs were significantly lower for the PMMA and PES groups compared with the PS group. After propensity score matching, HRs were significantly lower for the PMMA group than for the PS group. Conclusion The results suggest that the use of different membrane types may affect mortality in hemodialysis patients. However, further long-term prospective studies are needed to clarify these findings, including whether the use of the PMMA membrane can improve prognosis. PMID:28910324

Effect of dialyzer membrane materials on survival in chronic hemodialysis patients: Results from the annual survey of the Japanese Nationwide Dialysis Registry.

PubMed

Abe, Masanori; Hamano, Takayuki; Wada, Atsushi; Nakai, Shigeru; Masakane, Ikuto

2017-01-01

Little information is available regarding which type of dialyzer membrane results in good prognosis in patients on chronic hemodialysis. Therefore, we conducted a cohort study from a nationwide registry of hemodialysis patients in Japan to establish the association between different dialyzer membranes and mortality rates. We followed 142,412 patients on maintenance hemodialysis (female, 39.1%; mean age, 64.8 ± 12.3 years; median dialysis duration, 7 [4-12] years) for a year from 2008 to 2009. We included patients treated with seven types of high-flux dialyzer membranes at baseline, including cellulose triacetate (CTA), ethylene vinyl alcohol (EVAL), polyacrylonitrile (PAN), polyester polymer alloy (PEPA), polyethersulfone (PES), polymethylmethacrylate (PMMA), and polysulfone (PS). Cox regression was used to estimate the association between baseline dialyzers and all-cause mortality as hazard ratios (HRs) and 95% confidence intervals for 1-year mortality adjusting for potential confounders, and propensity score matching analysis was performed. The distribution of patients treated with each membrane was as follows: PS (56.0%), CTA (17.3%), PES (12.0%), PEPA (7.5%), PMMA (4.9%), PAN (1.2%), and EVAL (1.1%). When data were adjusted using basic factors, with PS as a reference group, the mortality rate was significantly higher in all groups except for the PES group. When data were further adjusted for dialysis-related factors, HRs were significantly higher for the CTA, EVAL, and PEPA groups. When the data were further adjusted for nutrition-and inflammation-related factors, HRs were significantly lower for the PMMA and PES groups compared with the PS group. After propensity score matching, HRs were significantly lower for the PMMA group than for the PS group. The results suggest that the use of different membrane types may affect mortality in hemodialysis patients. However, further long-term prospective studies are needed to clarify these findings, including whether the use of the PMMA membrane can improve prognosis.

Probing Ligand Effects on the Redox Energies of [4Fe-4S] Clusters Using Broken-Symmetry Density Functional Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu, Shuqiang; Ichiye, Toshiko

A central issue in understanding redox properties of iron-sulfur proteins is determining the factors that tune the reduction potentials of the Fe-S clusters. Recently, Solomon and coworkers have shown that the Fe-S bond covalency of protein analogs measured by %L, the percent ligand character of the Fe 3d orbitals, from ligand K-edge X-ray absorption spectroscopy (XAS) correlates with the electrochemical redox potentials. Also, Wang and coworkers have measured electron detachment energies for iron-sulfur clusters without environmental perturbations by gas-phase photoelectron spectroscopy (PES). Here the correlations of the ligand character with redox energy and %L character are examined in [Fe₄S₄L₄]2⁻ clustersmore » with different ligands by broken symmetry density functional theory (BS-DFT) calculations using the B3LYP functional together with PES and XAS experimental results. These gas-phase studies assess ligand effects independently of environmental perturbations and thus provide essential information for computational studies of iron-sulfur proteins. The B3LYP oxidation energies agree well with PES data, and the %L character obtained from natural bond orbital analysis correlates with XAS values, although it systematically underestimates them because of basis set effects. The results show that stronger electron-donating terminal ligands increase %Lt, the percent ligand character from terminal ligands, but decrease %Sb, the percent ligand character from the bridging sulfurs. Because the oxidized orbital has significant Fe-Lt antibonding character, the oxidation energy correlates well with %Lt. However, because the reduced orbital has varying contributions of both Fe-Lt and Fe-Sb antibonding character, the reduction energy does not correlate with either %Lt or %Sb. Overall, BSDFT calculations together with XAS and PES experiments can unravel the complex underlying factors in the redox energy and chemical bonding of the [4Fe-4S] clusters in iron-sulfur proteins.« less

Direct Determination of Lean Body Mass by CT in F-18 FDG PET/CT Studies: Comparison with Estimates Using Predictive Equations.

PubMed

Kim, Chang Guhn; Kim, Woo Hyoung; Kim, Myoung Hyoun; Kim, Dae-Weung

2013-06-01

The purpose of this study was to estimate lean body mass (LBM) using CT (LBM CTs) and compare the results with LBM estimates of four different predictive equations (LBM PEs) to assess whether LBM CTs and LBM PEs can be used interchangeably for SUV normalization. Whole-body F-18 FDG PET/CT studies were conducted on 392 patients. LBM CT1 is modified adipose tissue-free body mass, and LBM CT2 is adipose tissue-free body mass. Four different PEs were used for comparison (LBM PE1-4). Agreement between the two measurement methods was assessed by Bland-Altman analysis. We calculated the difference between two methods (bias), the percentage of difference, and the limits of agreement, expressed as a percentage. For LBM CTs vs. LBM PEs, except LBM PE3, the ranges of biases and limits of agreement were -3.77 to 3.81 kg and 26.60-35.05 %, respectively, indicating the wide limits of agreement and differing magnitudes of bias. For LBM CTs vs. LBM PE3, LBM PE3 had wider limits of agreement and greater positive bias (44.28-46.19 % and 10.49 to 14.04 kg, respectively), showing unacceptably large discrepancies between LBM CTs and LBM PE3. This study demonstrated that there are substantial discrepancies between individual LBM CTs and LBM PEs, and this should be taken into account when LBM CTs and LBM PEs are used interchangeably between patients.

Paclitaxel-eluting versus sirolimus-eluting stents in diabetes mellitus: a report from the National Heart, Lung, and Blood Institute Dynamic Registry.

PubMed

Wolf, William M; Vlachos, Helen A; Marroquin, Oscar C; Lee, Joon S; Smith, Conrad; Anderson, William D; Schindler, John T; Holper, Elizabeth M; Abbott, J Dawn; Williams, David O; Laskey, Warren K; Kip, Kevin E; Kelsey, Sheryl F; Mulukutla, Suresh R

2010-02-01

Diabetes is a powerful predictor of adverse events in patients undergoing percutaneous coronary intervention. Drug-eluting stents reduce restenosis rates compared with bare metal stents; however, controversy remains regarding which drug-eluting stents provides greater benefit in patients with diabetes. Accordingly, we compared the safety and efficacy of sirolimus-eluting stents (SES) with paclitaxel-eluting stents (PES) among diabetic patients in a contemporary registry. Using the National Heart, Lung, and Blood Institute Dynamic Registry, we evaluated 2-year outcomes of diabetic patients undergoing percutaneous coronary interventions with SES (n=677) and PES (n=328). Clinical and demographic characteristics, including age, body mass index, insulin use, left ventricular function, and aspirin/clopidogrel use postprocedure, did not differ significantly between the groups except that PES-treated patients had a greater frequency of hypertension and hyperlipidemia. At the 2-year follow-up, no significant differences were observed between PES and SES with regard to safety or efficacy end points. PES- and SES-treated patients had similar rates of death (10.7% versus 8.2%, P=0.20), death and myocardial infarction (14.9% versus 13.6%, P=0.55), repeat revascularization (14.8% versus 17.8%, P=0.36), and stent thrombosis (1.3% versus 1.3%, P=0.95). After adjustment, no significant differences between the 2 stent types in any outcome were observed. PES and SES are equally efficacious and have similar safety profiles in diabetic patients undergoing percutaneous coronary interventions in clinical practice.

Pharyngeal Electrical Stimulation for Treatment of Dysphagia in Subacute Stroke

PubMed Central

Scutt, Polly; Love, Jo; Clavé, Pere; Cohen, David; Dziewas, Rainer; Iversen, Helle K.; Ledl, Christian; Ragab, Suzanne; Soda, Hassan; Warusevitane, Anushka; Woisard, Virginie; Hamdy, Shaheen

2016-01-01

Background and Purpose— Dysphagia is common after stroke, associated with increased death and dependency, and treatment options are limited. Pharyngeal electric stimulation (PES) is a novel treatment for poststroke dysphagia that has shown promise in 3 pilot randomized controlled trials. Methods— We randomly assigned 162 patients with a recent ischemic or hemorrhagic stroke and dysphagia, defined as a penetration aspiration score (PAS) of ≥3 on video fluoroscopy, to PES or sham treatment given on 3 consecutive days. The primary outcome was swallowing safety, assessed using the PAS, at 2 weeks. Secondary outcomes included dysphagia severity, function, quality of life, and serious adverse events at 6 and 12 weeks. Results— In randomized patients, the mean age was 74 years, male 58%, ischemic stroke 89%, and PAS 4.8. The mean treatment current was 14.8 (7.9) mA and duration 9.9 (1.2) minutes per session. On the basis of previous data, 45 patients (58.4%) randomized to PES seemed to receive suboptimal stimulation. The PAS at 2 weeks, adjusted for baseline, did not differ between the randomized groups: PES 3.7 (2.0) versus sham 3.6 (1.9), P=0.60. Similarly, the secondary outcomes did not differ, including clinical swallowing and functional outcome. No serious adverse device-related events occurred. Conclusions— In patients with subacute stroke and dysphagia, PES was safe but did not improve dysphagia. Undertreatment of patients receiving PES may have contributed to the neutral result. Clinical Trial Registration— URL: http://www.controlled-trials.com. Unique identifier: ISRCTN25681641. PMID:27165955

Presence and Absence of Muscle Contraction Elicited by Peripheral Nerve Electrical Stimulation Differentially Modulate Primary Motor Cortex Excitability.

PubMed

Sasaki, Ryoki; Kotan, Shinichi; Nakagawa, Masaki; Miyaguchi, Shota; Kojima, Sho; Saito, Kei; Inukai, Yasuto; Onishi, Hideaki

2017-01-01

Modulation of cortical excitability by sensory inputs is a critical component of sensorimotor integration. Sensory afferents, including muscle and joint afferents, to somatosensory cortex (S1) modulate primary motor cortex (M1) excitability, but the effects of muscle and joint afferents specifically activated by muscle contraction are unknown. We compared motor evoked potentials (MEPs) following median nerve stimulation (MNS) above and below the contraction threshold based on the persistence of M-waves. Peripheral nerve electrical stimulation (PES) conditions, including right MNS at the wrist at 110% motor threshold (MT; 110% MNS condition), right MNS at the index finger (sensory digit nerve stimulation [DNS]) with stimulus intensity approximately 110% MNS (DNS condition), and right MNS at the wrist at 90% MT (90% MNS condition) were applied. PES was administered in a 4 s ON and 6 s OFF cycle for 20 min at 30 Hz. In Experiment 1 ( n = 15), MEPs were recorded from the right abductor pollicis brevis (APB) before (baseline) and after PES. In Experiment 2 ( n = 15), M- and F-waves were recorded from the right APB. Stimulation at 110% MNS at the wrist evoking muscle contraction increased MEP amplitudes after PES compared with those at baseline, whereas DNS at the index finger and 90% MNS at the wrist not evoking muscle contraction decreased MEP amplitudes after PES. M- and F-waves, which reflect spinal cord or muscular and neuromuscular junctions, did not change following PES. These results suggest that muscle contraction and concomitant muscle/joint afferent inputs specifically enhance M1 excitability.

Presence and Absence of Muscle Contraction Elicited by Peripheral Nerve Electrical Stimulation Differentially Modulate Primary Motor Cortex Excitability

PubMed Central

Sasaki, Ryoki; Kotan, Shinichi; Nakagawa, Masaki; Miyaguchi, Shota; Kojima, Sho; Saito, Kei; Inukai, Yasuto; Onishi, Hideaki

2017-01-01

Modulation of cortical excitability by sensory inputs is a critical component of sensorimotor integration. Sensory afferents, including muscle and joint afferents, to somatosensory cortex (S1) modulate primary motor cortex (M1) excitability, but the effects of muscle and joint afferents specifically activated by muscle contraction are unknown. We compared motor evoked potentials (MEPs) following median nerve stimulation (MNS) above and below the contraction threshold based on the persistence of M-waves. Peripheral nerve electrical stimulation (PES) conditions, including right MNS at the wrist at 110% motor threshold (MT; 110% MNS condition), right MNS at the index finger (sensory digit nerve stimulation [DNS]) with stimulus intensity approximately 110% MNS (DNS condition), and right MNS at the wrist at 90% MT (90% MNS condition) were applied. PES was administered in a 4 s ON and 6 s OFF cycle for 20 min at 30 Hz. In Experiment 1 (n = 15), MEPs were recorded from the right abductor pollicis brevis (APB) before (baseline) and after PES. In Experiment 2 (n = 15), M- and F-waves were recorded from the right APB. Stimulation at 110% MNS at the wrist evoking muscle contraction increased MEP amplitudes after PES compared with those at baseline, whereas DNS at the index finger and 90% MNS at the wrist not evoking muscle contraction decreased MEP amplitudes after PES. M- and F-waves, which reflect spinal cord or muscular and neuromuscular junctions, did not change following PES. These results suggest that muscle contraction and concomitant muscle/joint afferent inputs specifically enhance M1 excitability. PMID:28392766

In vivo antitumor potential of Ipomoea pes-caprae on melanoma cancer

PubMed Central

Manigauha, Ashish; Kharya, M. D.; Ganesh, N.

2015-01-01

Background: The incidence of skin cancers is rising gradually. The treatment of melanoma is also necessary to prevent the spread of cancer to other body organs. Scientific literatures have not documented any evidence of the antitumor potential of Ipomoea pes-caprae on melanoma. Aim of the Study: Explore in vivo antitumor potential of I. pes-caprae on melanoma cancer. Materials and Methods: Petroleum ether (60°C–80°C), methanolic and aqueous extracts, and swaras prepared from the whole herb of I. pes-caprae were assessed for their antitumor activity. The extracts and swaras at doses of 25 and 50 mg/kg b. wt. were administered intraperitoneal along with chemo and radiotherapy for 40 days for exploring antitumor activity against melanoma cancer (B16F10) in male C57BL mice. The results obtained from tumor volume, and histopathological studies were compared with the control and dacarbazine used as a standard. Results: Antitumor effect of I. pes-caprae extracts and swaras on melanoma cancer was found to be significant (P < 0.01) compared to normal control. The tumor volume inhibition against tumor-bearing mice, although differed from each other, was concentration dependent. Administration of plant extracts and swaras from the day 1 since tumor inducted. The induction of tumor was found delayed by 10–15 days and the tumor volume on the day 40 was similar to the Dacarbazine treatment used as a standard. Conclusion: The results obtained from the tumor volume and histopathological studies clearly revealed the antitumor potential of I. pes-caprae on melanoma cancer. PMID:25829785

Pharyngeal Electrical Stimulation for Treatment of Dysphagia in Subacute Stroke: A Randomized Controlled Trial.

PubMed

Bath, Philip M; Scutt, Polly; Love, Jo; Clavé, Pere; Cohen, David; Dziewas, Rainer; Iversen, Helle K; Ledl, Christian; Ragab, Suzanne; Soda, Hassan; Warusevitane, Anushka; Woisard, Virginie; Hamdy, Shaheen

2016-06-01

Dysphagia is common after stroke, associated with increased death and dependency, and treatment options are limited. Pharyngeal electric stimulation (PES) is a novel treatment for poststroke dysphagia that has shown promise in 3 pilot randomized controlled trials. We randomly assigned 162 patients with a recent ischemic or hemorrhagic stroke and dysphagia, defined as a penetration aspiration score (PAS) of ≥3 on video fluoroscopy, to PES or sham treatment given on 3 consecutive days. The primary outcome was swallowing safety, assessed using the PAS, at 2 weeks. Secondary outcomes included dysphagia severity, function, quality of life, and serious adverse events at 6 and 12 weeks. In randomized patients, the mean age was 74 years, male 58%, ischemic stroke 89%, and PAS 4.8. The mean treatment current was 14.8 (7.9) mA and duration 9.9 (1.2) minutes per session. On the basis of previous data, 45 patients (58.4%) randomized to PES seemed to receive suboptimal stimulation. The PAS at 2 weeks, adjusted for baseline, did not differ between the randomized groups: PES 3.7 (2.0) versus sham 3.6 (1.9), P=0.60. Similarly, the secondary outcomes did not differ, including clinical swallowing and functional outcome. No serious adverse device-related events occurred. In patients with subacute stroke and dysphagia, PES was safe but did not improve dysphagia. Undertreatment of patients receiving PES may have contributed to the neutral result. URL: http://www.controlled-trials.com. Unique identifier: ISRCTN25681641. © 2016 The Authors.

Does Transcranial Direct Current Stimulation Combined with Peripheral Electrical Stimulation Have an Additive Effect in the Control of Hip Joint Osteonecrosis Pain Associated with Sickle Cell Disease? A Protocol for a One-Session Double Blind, Block-Randomized Clinical Trial.

PubMed

Lopes, Tiago da Silva; Silva, Wellington Dos Santos; Ribeiro, Sânzia B; Figueiredo, Camila A; Campbell, Fernanda Q; Daltro, Gildasio de Cerqueira; Valenzuela, Antônio; Montoya, Pedro; Lucena, Rita de C S; Baptista, Abrahão F

2017-01-01

Chronic pain in Sickle Cell Disease (SCD) is probably related to maladaptive plasticity of brain areas involved in nociceptive processing. Transcranial Direct Current Stimulation (tDCS) and Peripheral Electrical Stimulation (PES) can modulate cortical excitability and help to control chronic pain. Studies have shown that combined use of tDCS and PES has additive effects. However, to date, no study investigated additive effects of these neuromodulatory techniques on chronic pain in patients with SCD. This protocol describes a study aiming to assess whether combined use of tDCS and PES more effectively alleviate pain in patients with SCD compared to single use of each technique. The study consists of a one-session double blind, block-randomized clinical trial (NCT02813629) in which 128 participants with SCD and femoral osteonecrosis will be enrolled. Stepwise procedures will occur on two independent days. On day 1, participants will be screened for eligibility criteria. On day 2, data collection will occur in four stages: sample characterization, baseline assessment, intervention, and post-intervention assessment. These procedures will last ~5 h. Participants will be divided into two groups according to homozygous for S allele (HbSS) ( n = 64) and heterozygous for S and C alleles (HbSC) ( n = 64) genotypes. Participants in each group will be randomly assigned, equally, to one of the following interventions: (1) active tDCS + active PES; (2) active tDCS + sham PES; (3) sham tDCS + active PES; and (4) sham tDCS + sham PES. Active tDCS intervention will consist of 20 min 2 mA anodic stimulation over the primary motor cortex contralateral to the most painful hip. Active PES intervention will consist of 30 min sensory electrical stimulation at 100 Hz over the most painful hip. The main study outcome will be pain intensity, measured by a Visual Analogue Scale. In addition, electroencephalographic power density, cortical maps of the gluteus maximus muscle elicited by Transcranial Magnetic Stimulation (TMS), serum levels of Brain-derived Neurotrophic Factor (BDNF), and Tumor Necrosis Factor (TNF) will be assessed as secondary outcomes. Data will be analyzed using ANOVA of repeated measures, controlling for confounding variables.

Calibration-quality adiabatic potential energy surfaces for H3(+) and its isotopologues.

PubMed

Pavanello, Michele; Adamowicz, Ludwik; Alijah, Alexander; Zobov, Nikolai F; Mizus, Irina I; Polyansky, Oleg L; Tennyson, Jonathan; Szidarovszky, Tamás; Császár, Attila G

2012-05-14

Calibration-quality ab initio adiabatic potential energy surfaces (PES) have been determined for all isotopologues of the molecular ion H(3)(+). The underlying Born-Oppenheimer electronic structure computations used optimized explicitly correlated shifted Gaussian functions. The surfaces include diagonal Born-Oppenheimer corrections computed from the accurate electronic wave functions. A fit to the 41,655 ab initio points is presented which gives a standard deviation better than 0.1 cm(-1) when restricted to the points up to 6000 cm(-1) above the first dissociation asymptote. Nuclear motion calculations utilizing this PES, called GLH3P, and an exact kinetic energy operator given in orthogonal internal coordinates are presented. The ro-vibrational transition frequencies for H(3)(+), H(2)D(+), and HD(2)(+) are compared with high resolution measurements. The most sophisticated and complete procedure employed to compute ro-vibrational energy levels, which makes explicit allowance for the inclusion of non-adiabatic effects, reproduces all the known ro-vibrational levels of the H(3)(+) isotopologues considered to better than 0.2 cm(-1). This represents a significant (order-of-magnitude) improvement compared to previous studies of transitions in the visible. Careful treatment of linear geometries is important for high frequency transitions and leads to new assignments for some of the previously observed lines. Prospects for further investigations of non-adiabatic effects in the H(3)(+) isotopologues are discussed. In short, the paper presents (a) an extremely accurate global potential energy surface of H(3)(+) resulting from high accuracy ab initio computations and global fit, (b) very accurate nuclear motion calculations of all available experimental line data up to 16,000 cm(-1), and (c) results suggest that we can predict accurately the lines of H(3)(+) towards dissociation and thus facilitate their experimental observation.

Calibration-quality adiabatic potential energy surfaces for H3+ and its isotopologues

NASA Astrophysics Data System (ADS)

Pavanello, Michele; Adamowicz, Ludwik; Alijah, Alexander; Zobov, Nikolai F.; Mizus, Irina I.; Polyansky, Oleg L.; Tennyson, Jonathan; Szidarovszky, Tamás; Császár, Attila G.

2012-05-01

Calibration-quality ab initio adiabatic potential energy surfaces (PES) have been determined for all isotopologues of the molecular ion H_3^+. The underlying Born-Oppenheimer electronic structure computations used optimized explicitly correlated shifted Gaussian functions. The surfaces include diagonal Born-Oppenheimer corrections computed from the accurate electronic wave functions. A fit to the 41 655 ab initio points is presented which gives a standard deviation better than 0.1 cm-1 when restricted to the points up to 6000 cm-1 above the first dissociation asymptote. Nuclear motion calculations utilizing this PES, called GLH3P, and an exact kinetic energy operator given in orthogonal internal coordinates are presented. The ro-vibrational transition frequencies for H_3^+, H2D+, and HD_2^+ are compared with high resolution measurements. The most sophisticated and complete procedure employed to compute ro-vibrational energy levels, which makes explicit allowance for the inclusion of non-adiabatic effects, reproduces all the known ro-vibrational levels of the H_3^+ isotopologues considered to better than 0.2 cm-1. This represents a significant (order-of-magnitude) improvement compared to previous studies of transitions in the visible. Careful treatment of linear geometries is important for high frequency transitions and leads to new assignments for some of the previously observed lines. Prospects for further investigations of non-adiabatic effects in the H_3^+ isotopologues are discussed. In short, the paper presents (a) an extremely accurate global potential energy surface of H_3^+ resulting from high accuracy ab initio computations and global fit, (b) very accurate nuclear motion calculations of all available experimental line data up to 16 000 cm-1, and (c) results suggest that we can predict accurately the lines of H_3^+ towards dissociation and thus facilitate their experimental observation.

The significance of the amorphous potential energy landscape for dictating glassy dynamics and driving solid-state crystallisation.

PubMed

Ruggiero, Michael T; Krynski, Marcin; Kissi, Eric Ofosu; Sibik, Juraj; Markl, Daniel; Tan, Nicholas Y; Arslanov, Denis; van der Zande, Wim; Redlich, Britta; Korter, Timothy M; Grohganz, Holger; Löbmann, Korbinian; Rades, Thomas; Elliott, Stephen R; Zeitler, J Axel

2017-11-15

The fundamental origins surrounding the dynamics of disordered solids near their characteristic glass transitions continue to be fiercely debated, even though a vast number of materials can form amorphous solids, including small-molecule organic, inorganic, covalent, metallic, and even large biological systems. The glass-transition temperature, T g , can be readily detected by a diverse set of techniques, but given that these measurement modalities probe vastly different processes, there has been significant debate regarding the question of why T g can be detected across all of them. Here we show clear experimental and computational evidence in support of a theory that proposes that the shape and structure of the potential-energy surface (PES) is the fundamental factor underlying the glass-transition processes, regardless of the frequency that experimental methods probe. Whilst this has been proposed previously, we demonstrate, using ab initio molecular-dynamics (AIMD) simulations, that it is of critical importance to carefully consider the complete PES - both the intra-molecular and inter-molecular features - in order to fully understand the entire range of atomic-dynamical processes in disordered solids. Finally, we show that it is possible to utilise this dependence to directly manipulate and harness amorphous dynamics in order to control the behaviour of such solids by using high-powered terahertz pulses to induce crystallisation and preferential crystal-polymorph growth in glasses. Combined, these findings provide compelling evidence that the PES landscape, and the corresponding energy barriers, are the ultimate controlling feature behind the atomic and molecular dynamics of disordered solids, regardless of the frequency at which they occur.

Exchange and Inelastic OH(+) + H Collisions on the Doublet and Quartet Electronic States.

PubMed

Bulut, Niyazi; Lique, François; Roncero, Octavio

2015-12-17

The exchange and inelastic state-to-state cross sections for the OH(+) + H collisions are computed from wave packet calculations using the doublet and quartet ground electronic potential energy surface (PES) correlating to the open shell reactants, for collision energies in the range of 1 meV to 0.7 eV. The doublet PES presents a deep insertion well, of ≈6 eV, but the exchange reaction has a rather low probability, showing that the mechanism is not statistical. This well is also responsible of a rather high rotational energy transfer, which makes the rigid-rotor approach overestimate the cross section for low Δj transitions and for high collisonal energies. The quartet PES, with a much shallower well, also presents a low exchange reaction cross section, but the inelastic state-to-state cross sections are very well reproduced by rigid-rotor calculations. When the electronic partition is used to obtain the total state-to-state cross section, the contribution of the doublet state becomes small, and the resulting total cross sections become close to those obtained for the quartet state. Thus, the total (quartet and doublet) cross sections for this open shell system can be reproduced rather satisfactorily by those obtained with the rigid-rotor approximation on the quartet state. Finally, we compare the new OH(+)-H cross sections with OH(+)-He ones recently computed. We found significant differences, especially for transitions with large Δj showing that specific OH(+)-H calculations had to be performed to accurately analyze the OH(+) emission from interstellar molecular clouds.

A theoretical study in extracting the essential features and dynamics of molecular motions: Intrinsic geometry methods for PF(5) pseudorotations and statistical methods for argon clusters

NASA Astrophysics Data System (ADS)

Panahi, Nima S.

We studied the problem of understanding and computing the essential features and dynamics of molecular motions through the development of two theories for two different systems. First, we studied the process of the Berry Pseudorotation of PF5 and the rotations it induces in the molecule through its natural and intrinsic geometric nature by setting it in the language of fiber bundles and graph theory. With these tools, we successfully extracted the essentials of the process' loops and induced rotations. The infinite number of pseudorotation loops were broken down into a small set of essential loops called "super loops", with their intrinsic properties and link to the physical movements of the molecule extensively studied. In addition, only the three "self-edge loops" generated any induced rotations, and then only a finite number of classes of them. Second, we studied applying the statistical methods of Principal Components Analysis (PCA) and Principal Coordinate Analysis (PCO) to capture only the most important changes in Argon clusters so as to reduce computational costs and graph the potential energy surface (PES) in three dimensions respectively. Both methods proved successful, but PCA was only partially successful since one will only see advantages for PES database systems much larger than those both currently being studied and those that can be computationally studied in the next few decades to come. In addition, PCA is only needed for the very rare case of a PES database that does not already include Hessian eigenvalues.

Effects of zero point vibration on the reaction dynamics of water dimer cations following ionization.

PubMed

Tachikawa, Hiroto

2017-06-30

Reactions of water dimer cation (H2O)2+ following ionization have been investigated by means of a direct ab initio molecular dynamics method. In particular, the effects of zero point vibration and zero point energy (ZPE) on the reaction mechanism were considered in this work. Trajectories were run on two electronic potential energy surfaces (PESs) of (H2O)2+: ground state ( 2 A″-like state) and the first excited state ( 2 A'-like state). All trajectories on the ground-state PES lead to the proton-transferred product: H 2 O + (Wd)-H 2 O(Wa) → OH(Wd)-H 3 O + (Wa), where Wd and Wa refer to the proton donor and acceptor water molecules, respectively. Time of proton transfer (PT) varied widely from 15 to 40 fs (average time of PT = 30.9 fs). The trajectories on the excited-state PES gave two products: an intermediate complex with a face-to-face structure (H 2 O-OH 2 ) + and a PT product. However, the proton was transferred to the opposite direction, and the reverse PT was found on the excited-state PES: H 2 O(Wd)-H 2 O + (Wa) → H 3 O + (Wd)-OH(Wa). This difference occurred because the ionizing water molecule in the dimer switched between the ground and excited states. The reaction mechanism of (H2O)2+ and the effects of ZPE are discussed on the basis of the results. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

A general method for constructing multidimensional molecular potential energy surfaces from {ital ab} {ital initio} calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, T.; Rabitz, H.

1996-02-01

A general interpolation method for constructing smooth molecular potential energy surfaces (PES{close_quote}s) from {ital ab} {ital initio} data are proposed within the framework of the reproducing kernel Hilbert space and the inverse problem theory. The general expression for an {ital a} {ital posteriori} error bound of the constructed PES is derived. It is shown that the method yields globally smooth potential energy surfaces that are continuous and possess derivatives up to second order or higher. Moreover, the method is amenable to correct symmetry properties and asymptotic behavior of the molecular system. Finally, the method is generic and can be easilymore » extended from low dimensional problems involving two and three atoms to high dimensional problems involving four or more atoms. Basic properties of the method are illustrated by the construction of a one-dimensional potential energy curve of the He{endash}He van der Waals dimer using the exact quantum Monte Carlo calculations of Anderson {ital et} {ital al}. [J. Chem. Phys. {bold 99}, 345 (1993)], a two-dimensional potential energy surface of the HeCO van der Waals molecule using recent {ital ab} {ital initio} calculations by Tao {ital et} {ital al}. [J. Chem. Phys. {bold 101}, 8680 (1994)], and a three-dimensional potential energy surface of the H{sup +}{sub 3} molecular ion using highly accurate {ital ab} {ital initio} calculations of R{umlt o}hse {ital et} {ital al}. [J. Chem. Phys. {bold 101}, 2231 (1994)]. In the first two cases the constructed potentials clearly exhibit the correct asymptotic forms, while in the last case the constructed potential energy surface is in excellent agreement with that constructed by R{umlt o}hse {ital et} {ital al}. using a low order polynomial fitting procedure. {copyright} {ital 1996 American Institute of Physics.}« less

The non-statistical dynamics of the 18O + 32O2 isotope exchange reaction at two energies

NASA Astrophysics Data System (ADS)

Van Wyngarden, Annalise L.; Mar, Kathleen A.; Quach, Jim; Nguyen, Anh P. Q.; Wiegel, Aaron A.; Lin, Shi-Ying; Lendvay, Gyorgy; Guo, Hua; Lin, Jim J.; Lee, Yuan T.; Boering, Kristie A.

2014-08-01

The dynamics of the 18O(3P) + 32O2 isotope exchange reaction were studied using crossed atomic and molecular beams at collision energies (Ecoll) of 5.7 and 7.3 kcal/mol, and experimental results were compared with quantum statistical (QS) and quasi-classical trajectory (QCT) calculations on the O3(X1A') potential energy surface (PES) of Babikov et al. [D. Babikov, B. K. Kendrick, R. B. Walker, R. T. Pack, P. Fleurat-Lesard, and R. Schinke, J. Chem. Phys. 118, 6298 (2003)]. In both QS and QCT calculations, agreement with experiment was markedly improved by performing calculations with the experimental distribution of collision energies instead of fixed at the average collision energy. At both collision energies, the scattering displayed a forward bias, with a smaller bias at the lower Ecoll. Comparisons with the QS calculations suggest that 34O2 is produced with a non-statistical rovibrational distribution that is hotter than predicted, and the discrepancy is larger at the lower Ecoll. If this underprediction of rovibrational excitation by the QS method is not due to PES errors and/or to non-adiabatic effects not included in the calculations, then this collision energy dependence is opposite to what might be expected based on collision complex lifetime arguments and opposite to that measured for the forward bias. While the QCT calculations captured the experimental product vibrational energy distribution better than the QS method, the QCT results underpredicted rotationally excited products, overpredicted forward-bias and predicted a trend in the strength of forward-bias with collision energy opposite to that measured, indicating that it does not completely capture the dynamic behavior measured in the experiment. Thus, these results further underscore the need for improvement in theoretical treatments of dynamics on the O3(X1A') PES and perhaps of the PES itself in order to better understand and predict non-statistical effects in this reaction and in the formation of ozone (in which the intermediate O3* complex is collisionally stabilized by a third body). The scattering data presented here at two different collision energies provide important benchmarks to guide these improvements.

C-H···O Hydrogen Bonding. The Prototypical Methane-Formaldehyde System: A Critical Assessment.

PubMed

Moore, Kevin B; Sadeghian, Keyarash; Sherrill, C David; Ochsenfeld, Christian; Schaefer, Henry F

2017-11-14

Distinguishing the functionality of C-H···O hydrogen bonds (HBs) remains challenging, because their properties are difficult to quantify reliably. Herein, we present a study of the model methane-formaldehyde complex (MFC). Six stationary points on the MFC potential energy surface (PES) were obtained at the CCSD(T)/ANO2 level. The CCSDT(Q)/CBS interaction energies of the conformers range from only -1.12 kcal mol -1 to -0.33 kcal mol -1 , denoting a very flat PES. Notably, only the lowest energy stationary point (MFC1) corresponds to a genuine minimum, whereas all other stationary points-including the previously studied ideal case of a e (C-H···O) = 180°-exhibit some degree of freedom that leads to MFC1. Despite the flat PES, we clearly see that the HB properties of MFC1 align with those of the prototypical water dimer O-H···O HB. Each HB property generally becomes less prominent in the higher-energy conformers. Only the MFC1 conformer prominently exhibits (1) elongated C-H donor bonds, (2) attractive C-H···O═C interactions, (3) n(O) → σ*(C-H) hyperconjugation, (4) critical points in the electron density from Bader's method and from the noncovalent interactions method, (5) positively charged donor hydrogen, and (6) downfield NMR chemical shifts and nonzero 2 J(C M -H M ···O F ) coupling constants. Based on this research, some issues merit further study. The flat PES hinders reliable determinations of the HB-induced shifts of the C-H stretches; a similarly difficult challenge is observed for the experiment. The role of charge transfer in HBs remains an intriguing open question, although our BLW and NBO computations suggest that it is relevant to the C-H···O HB geometries. These issues notwithstanding, the prominence of the HB properties in MFC1 serves as clear evidence that the MFC is predominantly bound by a C-H···O HB.

Lineshape theory of pigment-protein complexes: How the finite relaxation time of nuclei influences the exciton relaxation-induced lifetime broadening.

PubMed

Dinh, Thanh-Chung; Renger, Thomas

2016-07-21

In pigment-protein complexes, often the excited states are partially delocalized and the exciton-vibrational coupling in the basis of delocalized states contains large diagonal and small off-diagonal elements. This inequality may be used to introduce potential energy surfaces (PESs) of exciton states and to treat the inter-PES coupling in Markov and secular approximations. The resulting lineshape function consists of a Lorentzian peak that is broadened by the finite lifetime of the exciton states caused by the inter-PES coupling and a vibrational sideband that results from the mutual displacement of the excitonic PESs with respect to that of the ground state. So far analytical expressions have been derived that relate the exciton relaxation-induced lifetime broadening to the Redfield [T. Renger and R. A. Marcus, J. Chem. Phys. 116, 9997 (2002)] or modified Redfield [M. Schröder, U. Kleinekathöfer, and M. Schreiber, J. Chem. Phys. 124, 084903 (2006)] rate constants of exciton relaxation, assuming that intra-PES nuclear relaxation is fast compared to inter-PES transfer. Here, we go beyond this approximation and provide an analytical expression, termed Non-equilibrium Modified Redfield (NeMoR) theory, for the lifetime broadening that takes into account the finite nuclear relaxation time. In an application of the theory to molecular dimers, we find that, for a widely used experimental spectral density of the exciton-vibrational coupling of pigment-protein complexes, the NeMoR spectrum at low-temperatures (T < 150 K) is better approximated by Redfield than by modified Redfield theory. At room temperature, the lifetime broadening obtained with Redfield theory underestimates the NeMoR broadening, whereas modified Redfield theory overestimates it by a similar amount. A fortuitous error compensation in Redfield theory is found to explain the good performance of this theory at low temperatures. Since steady state spectra of PPCs are often measured at low temperatures, Redfield theory still provides a numerically efficient alternative to NeMoR theory. At higher temperatures, we suggest to use NeMoR theory, because it has the same numerical costs as modified Redfield theory, but is more accurate.

HeI photoelectron spectroscopic studies on the electronic structure of alkyl nitrosamines

NASA Astrophysics Data System (ADS)

Jiang, Peng; Qian, Ximei; Li, Chunhui; Qiao, Chunhua; Wang, Dianxun

1997-10-01

HeI photoelectron spectroscopic (PES) studies on the electronic structure of alkyl nitrosamines R 2N 2O (R = CH 3-, CH 3CH 2-, and CH 3CH 2CH 2-) are reported. The assignment of the PES bands for this series of compounds has been made with the aid of the band shapes, the band intensity and ab initio SCF MO calculations based on the 631 ∗ G basis sets. Both PES experiment and the ab initio SCF MO calculations show that the detoxification ability of nitrosamine with longer alkyl chain is stronger.

Evaluating Payments for Environmental Services: Methodological Challenges

PubMed Central

2016-01-01

Over the last fifteen years, Payments for Environmental Services (PES) schemes have become very popular environmental policy instruments, but the academic literature has begun to question their additionality. The literature attempts to estimate the causal effect of these programs by applying impact evaluation (IE) techniques. However, PES programs are complex instruments and IE methods cannot be directly applied without adjustments. Based on a systematic review of the literature, this article proposes a framework for the methodological process of designing an IE for PES schemes. It revises and discusses the methodological choices at each step of the process and proposes guidelines for practitioners. PMID:26910850

Pitch ranking, electrode discrimination, and physiological spread-of-excitation using Cochlear's dual-electrode mode.

PubMed

Goehring, Jenny L; Neff, Donna L; Baudhuin, Jacquelyn L; Hughes, Michelle L

2014-08-01

This study compared pitch ranking, electrode discrimination, and electrically evoked compound action potential (ECAP) spatial excitation patterns for adjacent physical electrodes (PEs) and the corresponding dual electrodes (DEs) for newer-generation Cochlear devices (Cochlear Ltd., Macquarie, New South Wales, Australia). The first goal was to determine whether pitch ranking and electrode discrimination yield similar outcomes for PEs and DEs. The second goal was to determine if the amount of spatial separation among ECAP excitation patterns (separation index, Σ) between adjacent PEs and the PE-DE pairs can predict performance on the psychophysical tasks. Using non-adaptive procedures, 13 subjects completed pitch ranking and electrode discrimination for adjacent PEs and the corresponding PE-DE pairs (DE versus each flanking PE) from the basal, middle, and apical electrode regions. Analysis of d' scores indicated that pitch-ranking and electrode-discrimination scores were not significantly different, but rather produced similar levels of performance. As expected, accuracy was significantly better for the PE-PE comparison than either PE-DE comparison. Correlations of the psychophysical versus ECAP Σ measures were positive; however, not all test/region correlations were significant across the array. Thus, the ECAP separation index is not sensitive enough to predict performance on behavioral tasks of pitch ranking or electrode discrimination for adjacent PEs or corresponding DEs.

Fluorocopolymer-coated nitinol self-expanding paclitaxel-eluting stent: pharmacokinetics and vascular biology responses in a porcine iliofemoral model.

PubMed

Hou, Dongming; Huibregtse, Barbara A; Eppihimer, Michael; Stoffregen, William; Kocur, Gordon; Hitzman, Cory; Stejskal, Elizabeth; Heil, John; Dawkins, Keith D

2016-08-20

Our aim was to evaluate arterial responses to paclitaxel and a novel fluorocopolymer-coated nitinol low-dose paclitaxel-eluting stent (FP-PES). Human smooth muscle cell (SMC) migration was assessed after exposure to paclitaxel in vitro. For pharmacokinetics and vascular response, FP-PES or bare metal stents (BMS) were implanted in porcine iliofemoral arteries. Paclitaxel significantly inhibited human coronary and femoral artery SMC migration at doses as low as 1 pM. Inhibition was significantly greater for femoral compared with coronary artery SMCs from 1 pM to 1 μM. Pharmacokinetics showed consistent paclitaxel release from FP-PES over the study duration. The peak arterial wall paclitaxel level was 3.7 ng/mg at 10 days, with levels decreasing to 50% of peak at 60 days and 10% at 180 days. Paclitaxel was not detected in blood or remote organs. Arteriogram and histomorphometry analyses showed FP-PES significantly inhibits neointimal proliferation versus BMS at 30 and 90 days. Re-endothelialisation scores were not different between groups. Paclitaxel affected femoral artery SMC migration at lower concentrations and to a greater degree than it did coronary artery SMCs. The novel FP-PES used in this preclinical study demonstrated a vascular healing response similar to BMS, while significantly inhibiting neointimal formation up to 90 days.

Pitch ranking, electrode discrimination, and physiological spread-of-excitation using Cochlear's dual-electrode mode

PubMed Central

Goehring, Jenny L.; Neff, Donna L.; Baudhuin, Jacquelyn L.; Hughes, Michelle L.

2014-01-01

This study compared pitch ranking, electrode discrimination, and electrically evoked compound action potential (ECAP) spatial excitation patterns for adjacent physical electrodes (PEs) and the corresponding dual electrodes (DEs) for newer-generation Cochlear devices (Cochlear Ltd., Macquarie, New South Wales, Australia). The first goal was to determine whether pitch ranking and electrode discrimination yield similar outcomes for PEs and DEs. The second goal was to determine if the amount of spatial separation among ECAP excitation patterns (separation index, Σ) between adjacent PEs and the PE-DE pairs can predict performance on the psychophysical tasks. Using non-adaptive procedures, 13 subjects completed pitch ranking and electrode discrimination for adjacent PEs and the corresponding PE-DE pairs (DE versus each flanking PE) from the basal, middle, and apical electrode regions. Analysis of d′ scores indicated that pitch-ranking and electrode-discrimination scores were not significantly different, but rather produced similar levels of performance. As expected, accuracy was significantly better for the PE-PE comparison than either PE-DE comparison. Correlations of the psychophysical versus ECAP Σ measures were positive; however, not all test/region correlations were significant across the array. Thus, the ECAP separation index is not sensitive enough to predict performance on behavioral tasks of pitch ranking or electrode discrimination for adjacent PEs or corresponding DEs. PMID:25096106

Improved human endometrial stem cells differentiation into functional hepatocyte-like cells on a glycosaminoglycan/collagen-grafted polyethersulfone nanofibrous scaffold.

PubMed

Khademi, Farzaneh; Ai, Jafar; Soleimani, Masoud; Verdi, Javad; Mohammad Tavangar, Seyed; Sadroddiny, Esmaeil; Massumi, Mohammad; Mahmoud Hashemi, Seyed

2017-11-01

Liver tissue engineering (TE) is rapidly emerging as an effective technique which combines engineering and biological processes to compensate for the shortage of damaged or destroyed liver tissues. We examined the viability, differentiation, and integration of hepatocyte-like cells on an electrospun polyethersulfone (PES) scaffold, derived from human endometrial stem cells (hEnSCs). Natural polymers were separately grafted on plasma-treated PES nanofibers, that is, collagen, heparan sulfate (HS) and collagen-HS. Galactosilated PES (PES-Gal) nanofibrous were created. The engineering and cell growth parameters were considered and compared with each sample. The cellular studies revealed increased cell survival, attachment, and normal morphology on the bioactive natural polymer-grafted scaffolds after 30 days of hepatic differentiation. The chemical and molecular assays displayed hepatocyte differentiation. These cells were also functional, showing glycogen storage, α-fetoprotein, and albumin secretion. The HS nanoparticle-grafted PES nanofibers demonstrated a high rate of cell proliferation, differentiation, and integration. Based on the observations mentioned above, engineered tissue is a good option in the future, for the commercial production of three-dimensional liver tissues for clinical purposes. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2516-2529, 2017. © 2016 Wiley Periodicals, Inc.

Levels of phthalate esters in settled house dust from urban dwellings with young children in Nanjing, China

NASA Astrophysics Data System (ADS)

Zhang, Qi; Lu, Xiao-Mei; Zhang, Xiao-Ling; Sun, Yong-Gang; Zhu, Dong-Mei; Wang, Bing-Ling; Zhao, Ren-Zheng; Zhang, Zheng-Dong

2013-04-01

To investigate the levels and possible determinants of phthalate esters (PEs) in settled house dust from urban dwellings with young children, dust was collected from 215 urban houses in Nanjing, China, and 145 outdoor settled dust samples were collected nearby. Six PEs were measured by gas chromatography/mass spectrometry. All PEs were detected in the dust from approximately 90% of the houses, with the exception of dioctyl phthalate (DOP), which had only a 59% detection rate. Di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DBP) were the most abundant PEs, with geometric means of 110 and 16.4 μg g-1, respectively, and maximal concentrations 9950 and 2150 μg g-1. Factor analysis showed that DBP, DEHP and benzyl butyl phthalate (BBP) might come from the same source and were significantly influenced by the use of solid-wood floor wax. High BBP, DEHP, DOP and total PE levels were associated with indices of dampness, and high DOP was associated with humidifier use. In conclusion, six PEs are ubiquitous in urban settled house dust in Nanjing, China, and both plastic materials and cosmetic and personal care products are important sources. Flooring material, dampness and humidifier use potentially influence house dust PE levels.

Investigations of Reactive Processes at Temperatures Relevant to the Hypersonic Flight Regime

DTIC Science & Technology

2014-10-31

molecule is constructed based on high- level ab-initio calculations and interpolated using the reproducible kernel Hilbert space (RKHS) method and...a potential energy surface (PES) for the ground state of the NO2 molecule is constructed based on high- level ab initio calculations and interpolated...between O(3P) and NO(2Π) at higher temperatures relevant to the hypersonic flight regime of reentering space- crafts. At a more fundamental level , we

Electronic structure of a laterally graded ZrO2-TiO2 film on Si(100) prepared by metal-organic chemical vapor deposition in ultrahigh vacuum

NASA Astrophysics Data System (ADS)

Richter, J. H.; Karlsson, P. G.; Sandell, A.

2008-05-01

A TiO2-ZrO2 film with laterally graded stoichiometry has been prepared by metal-organic chemical vapor deposition in ultrahigh vacuum. The film was characterized in situ using synchrotron radiation photoelectron spectroscopy (PES) and x-ray absorption spectroscopy. PES depth profiling clearly shows that Ti ions segregate toward the surface region when mixed with ZrO2. The binding energy of the ZrO2 electronic levels is constant with respect to the local vacuum level. The binding energy of the TiO2 electronic levels is aligned to the Fermi level down to a Ti /Zr ratio of about 0.5. At a Ti /Zr ratio between 0.1 and 0.5, the TiO2 related electronic levels become aligned to the local vacuum level. The addition of small amounts of TiO2 to ZrO2 results in a ZrO2 band alignment relative to the Fermi level that is less asymmetric than for pure ZrO2. The band edge positions shift by -0.6eV for a Ti /Zr ratio of 0.03. This is explained in terms of an increase in the work function when adding TiO2, an effect that becomes emphasized by Ti surface segregation.

Treatment of table olive processing wastewaters using novel photomodified ultrafiltration membranes as first step for recovering phenolic compounds.

PubMed

Garcia-Ivars, Jorge; Iborra-Clar, Maria-Isabel; Alcaina-Miranda, Maria-Isabel; Mendoza-Roca, José-Antonio; Pastor-Alcañiz, Laura

2015-06-15

Table olive processing wastewaters (TOPW) have high salt concentration and total phenolic content (TPC) causing many environmental problems. To reduce them, ultrafiltration (UF) was applied for treating TOPW. However, NaCl, which is the main responsible of salinity in TOPW, and phenols are small molecules that cannot be separated by conventional UF membranes. They have serious problems caused by fouling, which can be overcome using membrane modification techniques. For these reasons, photomodification may be an effective technique to obtain a stream rich in TPC due to the changes in membrane surface properties. UV-modification in the presence of two hydrophilic compounds (polyethylene glycol and aluminium oxide) was performed to achieve membranes with high reductions of organic matter and to keep the TPC as high as possible. Commercial polyethersulfone (PES) membranes of 30 kDa were used. Surface modification was evaluated using FTIR-ATR spectroscopy and membrane performance was studied by calculating the rejection ratios of colour, chemical oxygen demand (COD) and TPC. Results demonstrated that UF is a useful pre-treatment to reduce organic matter from TOPW, obtaining a permeate rich in TPC. PES/Al2O3 membranes displayed superior antifouling properties and rejection values, keeping high the TPC (>95%). Therefore, UF using modified membranes is an appropriate and sustainable technique for treating TOPW. Copyright © 2015 Elsevier B.V. All rights reserved.

Bound state potential energy surface construction: ab initio zero-point energies and vibrationally averaged rotational constants.

PubMed

Bettens, Ryan P A

2003-01-15

Collins' method of interpolating a potential energy surface (PES) from quantum chemical calculations for reactive systems (Jordan, M. J. T.; Thompson, K. C.; Collins, M. A. J. Chem. Phys. 1995, 102, 5647. Thompson, K. C.; Jordan, M. J. T.; Collins, M. A. J. Chem. Phys. 1998, 108, 8302. Bettens, R. P. A.; Collins, M. A. J. Chem. Phys. 1999, 111, 816) has been applied to a bound state problem. The interpolation method has been combined for the first time with quantum diffusion Monte Carlo calculations to obtain an accurate ground state zero-point energy, the vibrationally average rotational constants, and the vibrationally averaged internal coordinates. In particular, the system studied was fluoromethane using a composite method approximating the QCISD(T)/6-311++G(2df,2p) level of theory. The approach adopted in this work (a) is fully automated, (b) is fully ab initio, (c) includes all nine nuclear degrees of freedom, (d) requires no assumption of the functional form of the PES, (e) possesses the full symmetry of the system, (f) does not involve fitting any parameters of any kind, and (g) is generally applicable to any system amenable to quantum chemical calculations and Collins' interpolation method. The calculated zero-point energy agrees to within 0.2% of its current best estimate. A0 and B0 are within 0.9 and 0.3%, respectively, of experiment.

Limitations of Reverse Polyethylene Samplers (RePES) for Evaluating Toxicity of Field Contaminated Sediments

EPA Science Inventory

Passive samplers are used to measure dissolved nonionic organic contaminants (NOCs) in environmental media. More recently, reverse polyethylene samplers (RePES) have been used with spiked sediments to recreate interstitial water exposure concentrations and observed toxicity. In...

High-level theoretical rovibrational spectroscopy beyond fc-CCSD(T): The C3 molecule.

PubMed

Schröder, Benjamin; Sebald, Peter

2016-01-28

An accurate local (near-equilibrium) potential energy surface (PES) is reported for the C3 molecule in its electronic ground state (X̃(1)Σg (+)). Special care has been taken in the convergence of the potential relative to high-order correlation effects, core-valence correlation, basis set size, and scalar relativity. Based on the aforementioned PES, several rovibrational states of all (12)C and (13)C substituted isotopologues have been investigated, and spectroscopic parameters based on term energies up to J = 30 have been calculated. Available experimental vibrational term energies are reproduced to better than 1 cm(-1) and rotational constants show relative errors of not more than 0.01%. The equilibrium bond length has been determined in a mixed experimental/theoretical approach to be 1.294 07(10) Å in excellent agreement with the ab initio composite value of 1.293 97 Å. Theoretical band intensities based on a newly developed electric dipole moment function also suggest that the infrared active (1, 1(1), 0)←(0, 0(0), 0) combination band might be observable by high-resolution spectroscopy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shirkov, Leonid; Makarewicz, Jan, E-mail: jama@amu.edu.pl

An ab initio intermolecular potential energy surface (PES) has been constructed for the benzene-krypton (BKr) van der Waals (vdW) complex. The interaction energy has been calculated at the coupled cluster level of theory with single, double, and perturbatively included triple excitations using different basis sets. As a result, a few analytical PESs of the complex have been determined. They allowed a prediction of the complex structure and its vibrational vdW states. The vibrational energy level pattern exhibits a distinct polyad structure. Comparison of the equilibrium structure, the dipole moment, and vibrational levels of BKr with their experimental counterparts has allowedmore » us to design an optimal basis set composed of a small Dunning’s basis set for the benzene monomer, a larger effective core potential adapted basis set for Kr and additional midbond functions. Such a basis set yields vibrational energy levels that agree very well with the experimental ones as well as with those calculated from the available empirical PES derived from the microwave spectra of the BKr complex. The basis proposed can be applied to larger complexes including Kr because of a reasonable computational cost and accurate results.« less

VUV photoionization and dissociative photoionization of the prebiotic molecule acetyl cyanide: Theory and experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bellili, A.; Hochlaf, M., E-mail: hochlaf@univ-mlv.fr, E-mail: martin.schwell@lisa.u-pec.fr; Schwell, M., E-mail: hochlaf@univ-mlv.fr, E-mail: martin.schwell@lisa.u-pec.fr

2014-10-07

The present combined theoretical and experimental investigation concerns the single photoionization of gas-phase acetyl cyanide and the fragmentation pathways of the resulting cation. Acetyl cyanide (AC) is inspired from both the chemistry of cyanoacetylene and the Strecker reaction which are thought to be at the origin of medium sized prebiotic molecules in the interstellar medium. AC can be formed by reaction from cyanoacetylene and water but also from acetaldehyde and HCN or the corresponding radicals. In view of the interpretation of vacuum ultraviolet (VUV) experimental data obtained using synchrotron radiation, we explored the ground potential energy surface (PES) of acetylmore » cyanide and of its cation using standard and recently implemented explicitly correlated methodologies. Our PES covers the regions of tautomerism (between keto and enol forms) and of the lowest fragmentation channels. This allowed us to deduce accurate thermochemical data for this astrobiologically relevant molecule. Unimolecular decomposition of the AC cation turns out to be very complex. The implications for the evolution of prebiotic molecules under VUV irradiation are discussed.« less

Geckos significantly alter foot orientation to facilitate adhesion during downhill locomotion

PubMed Central

Birn-Jeffery, Aleksandra V.; Higham, Timothy E.

2014-01-01

Geckos employ their adhesive system when moving up an incline, but the directionality of the system may limit function on downhill surfaces. Here, we use a generalist gecko to test whether limb modulation occurs on downhill slopes to allow geckos to take advantage of their adhesive system. We examined three-dimensional limb kinematics for geckos moving up and down a 45° slope. Remarkably, the hind limbs were rotated posteriorly on declines, resulting in digit III of the pes facing a more posterior direction (opposite to the direction of travel). No significant changes in limb orientation were found in any other condition. This pes rotation leads to a dramatic shift in foot function that facilitates the use of the adhesive system as a brake/stabilizer during downhill locomotion and, although this rotation is not unique to geckos, it is significant for the deployment of adhesion. Adhesion is not just advantageous for uphill locomotion but can be employed to help deal with the effects of gravity during downhill locomotion, highlighting the incredible multi-functionality of this key innovation. PMID:25319816

Curiosity killed the cat: no evidence of an association between cat ownership and psychotic symptoms at ages 13 and 18 years in a UK general population cohort.

PubMed

Solmi, F; Hayes, J F; Lewis, G; Kirkbride, J B

2017-07-01

Congenital or early life infection with Toxoplasma gondii has been implicated in schizophrenia aetiology. Childhood cat ownership has been hypothesized as an intermediary marker of T. gondii infection and, by proxy, as a risk factor for later psychosis. Evidence supporting this hypothesis is, however, limited. We used birth cohort data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to investigate whether cat ownership in pregnancy and childhood (ages 4 and 10 years) was associated with psychotic experiences (PEs) in early (age 13, N = 6705) and late (age 18, N = 4676) adolescence, rated from semi-structured interviews. We used logistic regression to examine associations between cat ownership and PEs, adjusting for several sociodemographic and socioeconomic factors, household characteristics and dog ownership. Missing data were handled via multiple imputation. Cat ownership during pregnancy was not associated with PEs at age 13 years [adjusted odds ratio (OR) 1.15, 95% confidence interval (CI) 0.97-1.35] or 18 years (OR 1.08, 95% CI 0.86-1.35). Initial univariable evidence that cat ownership at ages 4 and 10 years was associated with PEs at age 13 years did not persist after multivariable adjustment (4 years: OR 1.18, 95% CI 0.94-1.48; 10 years: OR 1.12, 95% CI 0.92-1.36). There was no evidence that childhood cat ownership was associated with PEs at age 18 years. While pregnant women should continue to avoid handling soiled cat litter, given possible T. gondii exposure, our study strongly indicates that cat ownership in pregnancy or early childhood does not confer an increased risk of later adolescent PEs.

Computing payment for ecosystem services in watersheds: an analysis of the Middle Route Project of South-to-North Water Diversion in China.

PubMed

Dong, Zhengju; Yan, Yan; Duan, Jing; Fu, Xiao; Zhou, Qingrong; Huang, Xiang; Zhu, Xiangen; Zhao, Jingzhu

2011-01-01

Payment for ecosystem services (PES) has attracted considerable attention as an economic incentive for promoting natural resource management recently. As emphasis has been placed on using the incentive-based mechanism by the central government, rapid progress on PES research and practice has been achieved. However PES still faces many difficulties. A key issue is the lack of a fully-fledged theory and method to clearly define the design scope, accounting and feasibility of PES criteria. An improved watershed criteria model was developed in light of research on PES practices in China, investigations on the water source area for the Middle Route Project of South-to-North Water Diversion and ecosystem services outflows theory. The basic principle of assessment is the direct and opportunity cost for ecological conservation and environmental protection in the water source area deduct nationally-financed PES and internal effect. Then the scope and the criteria methods were determined, and internal effect was put forward to define benefits brought from water source area. Finally, Shiyan City, which is the main water source area for the Project of Water Diversion, was analyzed by this model and its payment was calculated. The results showed that: (1) during 2003-2050, the total direct cost and opportunity cost would reach up to 262.70 billion and 256.33 billion Chinese Yuan (CNY, 2000 constant prices), i.e., 50.61% and 49.38% of total cost, respectively; (2) Shiyan City would gain 0.23, 0.06 and 0.03 CNY/m3 in 2014-2020, 2021-2030, and 2031-2050, respectively.

Trajectories of Early Childhood Developmental Skills and Early Adolescent Psychotic Experiences: Findings from the ALSPAC UK Birth Cohort.

PubMed

Hameed, Mohajer A; Lingam, Raghu; Zammit, Stanley; Salvi, Giovanni; Sullivan, Sarah; Lewis, Andrew J

2017-01-01

Objective: The aim of this study was to use prospective data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine association between trajectories of early childhood developmental skills and psychotic experiences (PEs) in early adolescence. Method: This study examined data from n = 6790 children from the ALSPAC cohort who participated in a semi-structured interview to assess PEs at age 12. Child development was measured using parental report at 6, 18, 30, and 42 months of age using a questionnaire of items adapted from the Denver Developmental Screening Test - II. Latent class growth analysis was used to generate trajectories over time for measures of fine and gross motor development, social, and communication skills. Logistic regression was used to investigate associations between developmental trajectories in each of these early developmental domains and PEs at age 12. Results: The results provided evidence that decline rather than enduringly poor social (adjusted OR = 1.28, 95% CI = 1.10-1.92, p = 0.044) and communication skills (adjusted OR 1.12, 95% CI = 1.03-1.22, p = 0.010) is predictive of suspected or definite PEs in early adolescence, than those with stable and/or improving skills. Motor skills did not display the same pattern of association; although gender specific effects provided evidence that only declining pattern of fine motor skills was associated with suspected and definite PEs in males compared to females (interaction OR = 1.47, 95% CI = 1.09-1.97, p = 0.012). Conclusion: Findings suggest that decline rather than persistent impairment in social and communication skills were most predictive of PEs in early adolescence. Findings are discussed in terms of study's strengths, limitations, and clinical implications.

Lean body mass: the development and validation of prediction equations in healthy adults

PubMed Central

2013-01-01

Background There is a loss of lean body mass (LBM) with increasing age. A low LBM has been associated with increased adverse effects from prescribed medications such as chemotherapy. Accurate assessment of LBM may allow for more accurate drug prescribing. The aims of this study were to develop new prediction equations (PEs) for LBM with anthropometric and biochemical variables from a development cohort and then validate the best performing PEs in validation cohorts. Methods PEs were developed in a cohort of 188 healthy subjects and then validated in a convenience cohort of 52 healthy subjects. The best performing anthropometric PE was then compared to published anthropometric PEs in an older (age ≥ 50 years) cohort of 2287 people. Best subset regression analysis was used to derive PEs. Correlation, Bland-Altman and Sheiner & Beal methods were used to validate and compare the PEs against dual X-ray absorptiometry (DXA)-derived LBM. Results The PE which included biochemistry variables performed only marginally better than the anthropometric PE. The anthropometric PE on average over-estimated LBM by 0.74 kg in the combined cohort. Across gender (male vs. female), body mass index (< 22, 22- < 27, 27- < 30 and ≥30 kg/m2) and age groups (50–64, 65–79 and ≥80 years), the maximum mean over-estimation of the anthropometric PE was 1.36 kg. Conclusions A new anthropometric PE has been developed that offers an alternative for clinicians when access to DXA is limited. Further research is required to determine the clinical utility and if it will improve the safety of medication use. PMID:24499708

Immunoregulatory cytokines in mouse placental extracts inhibit in vitro osteoclast differentiation of murine macrophages.

PubMed

Canellada, A; Custidiano, A; Abraham, F; Rey, E; Gentile, T

2013-03-01

Previous studies showed that placental extracts (PE) alleviates arthritic symptoms in animal models of arthritis. To evaluate whether murine PEs obtained at embryonic days 7.5 (PE7) and 17.5 (PE18) regulate RANKL-induced osteoclast differentiation, RAW 264.7 cells were cultured with RANKL and MCSF in presence or not of PEs. Tartrate-resistant acid phosphatase (TRAP) was stained and multinucleated TRAP positive cells were visualized under a light microscope. Cathepsin K and metalloprotease expression was assessed by RT-PCR and gelatin zymography respectively. NFATc1 expression was determined by immunoblot. To analyze NFAT-dependent transcription, macrophages were transfected with a luciferase reporter plasmid. Cytokines were determined in PEs by ELISA and immunoblot. Transforming growth factor (TGF)- beta and Interleukin (IL)-10 receptor were inhibited in cell cultures with specific antibodies. PE7 and PE18 inhibited RANKL-induced multinucleated TRAP positive cells, Cathepsin K expression and metalloprotease activity, as well as NFATc1 expression and activity, thereby inhibiting osteoclast differentiation of RAW cells. Inflammatory/Regulatory cytokine ratio was higher in PE7 than in PE18. Blocking TGF-beta abolished the effect of both, PE7 and PE18, on multinucleated TRAP positive cells and metalloprotease expression, whereas blocking IL-10 receptor reverted the effect of PE18 but not of PE7. Inhibition of osteoclast differentiation by PEs was not unexpected, since cytokines detected in extracts were previously found to regulate osteoclast differentiation. PEs inhibited osteoclast differentiation of macrophages in vitro. Downregulation of NFATc1 might be involved in this effect. Regulatory/Th2 cytokines play a role in the effect of PEs on osteoclast differentiation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Curiosity killed the cat: No evidence of an association between cat ownership and psychotic symptoms at age 13 and 18 years in a UK general population cohort

PubMed Central

Solmi, F.; Hayes, J.F; Lewis, G.; Kirkbride, J.B

2018-01-01

Background Congenital or early life infection with Toxoplasma Gondii has been implicated in schizophrenia aetiology. Childhood cat ownership has been hypothesised as an intermediary marker of T. Gondii infection and, by proxy, as a risk factor for later psychosis. Evidence supporting this hypothesis is, however, limited. Method We used birth cohort data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to investigate whether cat ownership in pregnancy and childhood (4, 10 years old) was associated with psychotic experiences (PEs) in early (age 13; N=6,705) and late (age 18; N=4,676) adolescence, rated from semi-structured interviews. We used logistic regression to examine associations between cat ownership and PEs, adjusting for several sociodemographic and socioeconomic factors, household characteristics and dog ownership. Missing data were handled via multiple imputation. Results Cat ownership during pregnancy was not associated with PEs at age 13 (adjusted odds ratio [OR]: 1.15, 95% confidence interval [CI]: 0.97-1.35) or 18 years (OR: 1.08, 95%CI: 0.86-1.35). Initial univariable evidence that cat ownership at 4 and 10 years was associated with PEs at age 13 years did not persist after multivariable adjustment (4 years OR: 1.18, 95%CI: 0.94-1.48; 10 years OR 1.12, 95%CI: 0.92; 1.36). There was no evidence that childhood cat ownership was associated with PEs at 18 years old. Conclusions While pregnant women should continue to avoid handling soiled cat litter, given possible T Gondii exposure, our study strongly indicates that cat ownership in pregnancy or early childhood does not confer an increased risk of later adolescent PEs. PMID:28222824

Outcomes of Patients Treated with the Everolimus- versus the Paclitaxel-Eluting Stents in a Consecutive Cohort of Patients at a Tertiary Medical Center.

PubMed

Shammas, Nicolas W; Shammas, Gail A; Nader, Elie; Jerin, Michael; Mrad, Luay; Ehrecke, Nicholas; Shammas, Waheeb J; Voelliger, Cara M; Hafez, Alexander; Kelly, Ryan; Reynolds, Emily

2013-09-01

In this study, we compare the outcomes of the paclitaxel-eluting stent (PES) versus the everolimus-eluting stent (EES) treated patients at a tertiary medical center and up to 2 years follow-up. Unselected consecutive patients were retrospectively recruited following stenting with PES (159 patients) or EES (189 patients). The primary endpoint of the study was target lesion failure (TLF), defined as the combined endpoint of cardiac death, nonfatal myocardial infarction (MI), or target lesion revascularization (TLR). Secondary endpoints included target vessel revascularization (TVR), TLR, target vessel failure (TVF), acute stent thrombosis (ST), total death, cardiac death, and nonfatal MI. Patients treated with the PES stent had less congestive heart failure and restenotic lesions, but a higher prevalence of longer lesions, nonleft main bifurcations, required more stents per patient (4.3 ± 2.8 vs. 2.9 ± 2.1). TLF occurred in 32.3% PES versus 21.5% EES (p = 0.027). The secondary unadjusted endpoints for PES versus EES, respectively, were TVF 38.6 versus 30.7% (p = 0.140), TVR 35.7 versus 26.5% (p = 0.079), definite and probable ST 1.2 versus 0.0%, nonfatal MI 4.5 versus 4.2%, and mortality 9.6 versus 4.0%. Logistic regression analysis showed that the numbers of stents per patient (p = 0.001), age (p = 0.01), and renal failure (p = 0.045) were independent predictors of TLF. Using univariate analysis, EES had lower TLF than PES in a cohort of unselected patients undergoing percutaneous coronary intervention at 2 years follow-up. Multivariate analysis showed that the numbers of stents per patient, age, and renal failure, but not stent type, were predictors of TLF.

A Population-based Longitudinal Study of Childhood Neurodevelopmental Disorders, IQ and Subsequent Risk of Psychotic Experiences in Adolescence

PubMed Central

Khandaker, Golam M.; Stochl, Jan; Zammit, Stanley; Lewis, Glyn; Jones, Peter B

2014-01-01

Background Schizophrenia has a neurodevelopmental component to its origin, and may share overlapping pathogenic mechanisms with childhood neurodevelopmental disorders (ND). Yet longitudinal studies of psychotic outcomes among individuals with ND are limited. We report a population-based prospective study of six common childhood ND, subsequent neurocognitive performance and the risk of psychotic experiences (PEs) in early adolescence. Methods PEs were assessed by semi-structured interviews at age 13 years. IQ and working memory were measured between ages 9 and 11 years. The presence of six neurodevelopmental disorders (autism spectrum, dyslexia, dyspraxia, dysgraphia, dysorthographia, dyscalculia) was determined from parent-completed questionnaire at age 9 years. Linear regression calculated mean difference in cognitive scores between those with and without ND. The association between ND and PEs was expressed as odds ratio (OR); effects of cognitive deficits were examined. Potential confounders included age, gender, father’s social class, ethnicity and maternal education. Results Out of 8,220 children, 487 (5.9%) were reported to have ND at age 9 years. Children with, compared with those without ND performed worse on all cognitive measures; adjusted mean difference in total IQ 6.84 (95% CI 5.00- 8.69). The association between total IQ and ND was linear (p<0.0001). The risk of PEs was higher in those with, compared with those without ND; adjusted OR for definite PEs 1.76 (95% CI 1.11- 2.79). IQ (but not working memory) deficit partly explained this association. Conclusion Higher risk of PEs in early adolescence among individuals with childhood ND is consistent with the neurodevelopmental hypothesis of schizophrenia. PMID:25066026

Planning Instruction to Meet the Intent of the Next Generation Science Standards

NASA Astrophysics Data System (ADS)

Krajcik, Joseph; Codere, Susan; Dahsah, Chanyah; Bayer, Renee; Mun, Kongju

2014-03-01

The National Research Council's Framework for K- 12 Science Education and the Next Generation Science Standards (NGSS Lead States in Next Generation Science Standards: For states, by states. The National Academies Press, Washington, 2013) move teaching away from covering many isolated facts to a focus on a smaller number of disciplinary core ideas (DCIs) and crosscutting concepts that can be used to explain phenomena and solve problems by engaging in science and engineering practices. The NGSS present standards as knowledge-in-use by expressing them as performance expectations (PEs) that integrate all three dimensions from the Framework for K- 12 Science Education. This integration of core ideas, practices, and crosscutting concepts is referred to as three-dimensional learning (NRC in Division of Behavioral and Social Sciences and Education. The National Academies Press, Washington, 2014). PEs state what students can be assessed on at the end of grade level for K-5 and at the end of grade band for 6-8 and 9-12. PEs do not specify how instruction should be developed nor do they serve as objectives for individual lessons. To support students in developing proficiency in the PEs, the elements of the DCIs will need to be blended with various practices and crosscutting concepts. In this paper, we examine how to design instruction to support students in meeting a cluster or "bundle" of PEs and how to blend the three dimensions to develop lesson level PEs that can be used for guiding instruction. We provide a ten-step process and an example of that process that teachers and curriculum designers can use to design lessons that meet the intent of the Next Generation of Science Standards.

Trajectories of Early Childhood Developmental Skills and Early Adolescent Psychotic Experiences: Findings from the ALSPAC UK Birth Cohort

PubMed Central

Hameed, Mohajer A.; Lingam, Raghu; Zammit, Stanley; Salvi, Giovanni; Sullivan, Sarah; Lewis, Andrew J.

2018-01-01

Objective: The aim of this study was to use prospective data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine association between trajectories of early childhood developmental skills and psychotic experiences (PEs) in early adolescence. Method: This study examined data from n = 6790 children from the ALSPAC cohort who participated in a semi-structured interview to assess PEs at age 12. Child development was measured using parental report at 6, 18, 30, and 42 months of age using a questionnaire of items adapted from the Denver Developmental Screening Test – II. Latent class growth analysis was used to generate trajectories over time for measures of fine and gross motor development, social, and communication skills. Logistic regression was used to investigate associations between developmental trajectories in each of these early developmental domains and PEs at age 12. Results: The results provided evidence that decline rather than enduringly poor social (adjusted OR = 1.28, 95% CI = 1.10–1.92, p = 0.044) and communication skills (adjusted OR 1.12, 95% CI = 1.03–1.22, p = 0.010) is predictive of suspected or definite PEs in early adolescence, than those with stable and/or improving skills. Motor skills did not display the same pattern of association; although gender specific effects provided evidence that only declining pattern of fine motor skills was associated with suspected and definite PEs in males compared to females (interaction OR = 1.47, 95% CI = 1.09–1.97, p = 0.012). Conclusion: Findings suggest that decline rather than persistent impairment in social and communication skills were most predictive of PEs in early adolescence. Findings are discussed in terms of study’s strengths, limitations, and clinical implications. PMID:29375433

Overcoming Barriers to Public Engagement through a Multi-Institution Consortium

NASA Astrophysics Data System (ADS)

Lambert, K. F.; Weiss, M.; Garlick, S.

2016-12-01

A growing body of evidence suggests that public engagement with science (PES) can enhance the relevance and impact of science on society. At the same time, advances in our understanding of public engagement suggest that greater skills, resources, and time horizons are often required to create effective programs. Consequently, despite a proliferation of training programs, many scientists still face the challenge of balancing the demands of public engagement with the requirements of their disciplinary research. Novel institutions are emerging that bring together interdisciplinary networks of principle investigators with PES practitioners to overcome barriers to effective and sustained public engagement in the environmental sciences. We will use the Science Policy Exchange (SPE), a consortium housed at the Harvard Forest, Harvard University, to illustrate how PIs and PES practitioners can collaborate to design public engagement processes, conduct policy-relevant scientific syntheses, and implement science communication strategies. Results from two SPE case studies demonstrate how multi-institutional consortia can help scientists overcome barriers such as lack of knowledge of evidence-based PES approaches, limits on time and funding to implement PES projects, and the need to integrate PES activities with research. The case studies also show how SPE strives to achieve credibility, saliency, and legitimacy in different public policy contexts: (1) engagement between scientists and local stakeholders to develop scenarios of landscape change; and (2) engagement between scientists and policy makers to understand the relationship between power plant emission standards, and air quality, human health and ecosystem function. The presentation will conclude with examples of how SPE programs have led to institutional change (staffing and budget), cultural change (attitudes and expectations of senior leaders), and research change (development of research questions, funding proposals, and research design).

gender-specific outcome after paclitaxel-eluting stent implantation in japanese patients with coronary artery disease--sub-analysis of the Japan TAXUS Express2 post-marketing survey.

PubMed

Okura, Hiroyuki; Nakamura, Masato; Kotani, Jun-Ichi; Kozuma, Ken

2013-01-01

 Although previous randomized and non-randomized studies have demonstrated the safety and efficacy of paclitaxel-eluting stents (PES), a higher revascularization rate has been reported in women than in men. A sub-analysis of the TAXUS Japan Post-market Surveillance Study (TAXUS-PMS) was done to assess the influence of gender on clinical outcome.  A total of 2,132 PES-treated Japanese patients (women, n=551) from this registry were analyzed. Subjects were stratified by gender to compare 1-year clinical outcome. PES-treated women were older and more likely to have insulin-treated diabetes and hypertension. In contrast, PES-treated men were more likely to be smokers, have a previous history of myocardial infarction, and lower ejection fraction. While cardiac death, myocardial infarction and stent thrombosis were similar between men and women, major cardiac events tended to be lower in women than in men (6.4% vs. 8.8%, P=0.08). Although women had significantly smaller reference vessel size (2.46±0.53 mm vs. 2.59±0.60 mm, P<0.0001), the restenosis rate tended to be lower in women than in men (11.5% vs. 14.8%, P=0.11). Subsequently, the target lesion revascularization rate was significantly lower in women than in men (4.2% vs. 6.5%, P<0.05).  Despite a higher risk profile, Japanese women treated with PES did not have a higher rate of repeat revascularization or major adverse clinical outcome than PES-treated men at 1 year. 

Quantification of free formaldehyde in carrageenan and processed Eucheuma seaweed using high-performance liquid chromatography.

PubMed

Hornshøj, Bettina Høj; Kobbelgaard, Sara; Blakemore, William R; Stapelfeldt, Henrik; Bixler, Harris J; Klinger, Markus

2015-01-01

In 2010 the European Commission placed a limit on the amount of free formaldehyde in carrageenan and processed Eucheuma seaweed (PES) of 5 mg kg(-1). Formaldehyde is not used in carrageenan and PES processing and accordingly one would not expect free formaldehyde to be present in carrageenan and PES. However, surprisingly high levels up to 10 mg kg(-1) have been found using the generally accepted AOAC and Hach tests. These findings are, per proposed reaction pathways, likely due to the formation of formaldehyde when sulphated galactose, the backbone of carrageenan, is hydrolysed with the strong acid used in these conventional tests. In order to minimise the risk of false-positives, which may lead to regulatory non-compliance, a new high-performance liquid chromatography (HPLC) method has been developed. Initially, carrageenan or PES is extracted with 2-propanol and subsequently reacted with 2,4-dinitrophenylhydrazine (DNPH) to form the chromophore formaldehyde-DNPH, which is finally quantified by reversed-phase HPLC with ultraviolet light detection at 355 nm. This method has been found to have a limit of detection of 0.05 mg kg(-1) and a limit of quantification of 0.2 mg kg(-1). Recoveries from samples spiked with known quantities of formaldehyde were 95-107%. Using this more specific technique, 20 samples of carrageenan and PES were tested for formaldehyde. Only one sample had a detectable content of formaldehyde (0.40 mg kg(-1)), thus demonstrating that the formaldehyde content of commercial carrageenan and PES products are well below the European Commission maximum limit of 5 mg kg(-1).

The Use of Ecological Indicators as a Basis for Operationalizing a PES Scheme on Forest Conservation in Northern Argentina

NASA Astrophysics Data System (ADS)

Gobbi, José; Deguillon, Marie

2017-04-01

Payments for ecosystem services (PES) aim to improve the supply of ecosystem services (ES) by making payments to service providers, which are conditional on the provision of those services. Payments cannot be conditional unless the service can be effectively monitored. Direct monitoring of ES to assess conditionality could be methodologically complex and operatively expensive. To overcome such constraints, the pilot "GEF-PES Project" of Northern Argentina has developed a set of five indicators on forest conservation status (CS) as a basis for estimating the amount of ES provided -considering a positive correlation between the CS of a forest and its level of provision of ecosystem services -and for operationalizing the PES. Field data indicate that selected indicators: (i) exhibit strong correlation with the amount of carbon and biodiversity provided by forests according to their CS, ii) are cost-effective to monitor ES conditionality and (iii) allow easy application of payment levels.

Small leucine-rich repeat proteoglycans associated with mature insoluble elastin serve as binding sites for galectins.

PubMed

Itoh, Aiko; Nonaka, Yasuhiro; Ogawa, Takashi; Nakamura, Takanori; Nishi, Nozomu

2017-11-01

We previously reported that galectin-9 (Gal-9), an immunomodulatory animal lectin, could bind to insoluble collagen preparations and exerted direct cytocidal effects on immune cells. In the present study, we found that mature insoluble elastin is capable of binding Gal-9 and other members of the human galectin family. Lectin blot analysis of a series of commercial water-soluble elastin preparations, PES-(A) ~ PES-(E), revealed that only PES-(E) contained substances recognized by Gal-9. Gal-9-interacting substances in PES-(E) were affinity-purified, digested with trypsin and then analyzed by reversed-phase HPLC. Peptide fragments derived from five members of the small leucine-rich repeat proteoglycan family, versican, lumican, osteoglycin/mimecan, prolargin, and fibromodulin, were identified by N-terminal amino acid sequence analysis. The results indicate that Gal-9 and possibly other galectins recognize glycans attached to small leucine-rich repeat proteoglycans associated with insoluble elastin and also indicate the possibility that mature insoluble elastin serves as an extracellular reservoir for galectins.

Palisade endings and proprioception in extraocular muscles: a comparison with skeletal muscles.

PubMed

Lienbacher, Karoline; Horn, Anja K E

2012-12-01

This article describes current views on motor and sensory control of extraocular muscles (EOMs) based on anatomical data. The special morphology of EOMs, including their motor innervation, is described in comparison to classical skeletal limb and trunk muscles. The presence of proprioceptive organs is reviewed with emphasis on the palisade endings (PEs), which are unique to EOMs, but the function of which is still debated. In consideration of the current new anatomical data about the location of cell bodies of PEs, a hypothesis on the function of PEs in EOMs and the multiply innervated muscle fibres they are attached to is put forward.

The training and employment of teachers of physical education and sports in Turkey.

PubMed

Yildiz, Suleyman M

2012-03-01

This paper examines the phenomenon of training teachers of Physical Education and Sports (PES) in Turkey with respect to its dimensions of student quotas, graduates, and employment; and performs analytical evaluations through the numeric data. In the last five years, the number of labor force participants in PES teaching posts was 14,459 on average and the average employment volume was 10.29%, which means that a great number of graduates have accumulated against employment. Thus, this indicates that no realistic planning was done in the past years "so as to create a supply-demand equilibrium between training and employment of PES teachers".

Two-component, ab initio potential energy surface for CO2—H2O, extension to the hydrate clathrate, CO2@(H2O)20, and VSCF/VCI vibrational analyses of both

NASA Astrophysics Data System (ADS)

Wang, Qingfeng Kee; Bowman, Joel M.

2017-10-01

We report an ab initio, full-dimensional, potential energy surface (PES) for CO2—H2O, in which two-body interaction energies are fit using a basis of permutationally invariant polynomials and combined with accurate potentials for the non-interacting monomers. This approach which we have termed "plug and play" is extended here to improve the precision of the 2-body fit in the long range. This is done by combining two separate fits. One is a fit to 47 593 2-body energies in the region of strong interaction and approaching the long range, and the second one is a fit to 6244 2-body energies in the long range. The two fits have a region of overlap which permits a smooth switch from one to the other. All energies are obtained at the CCSD(T)-F12b/aug-cc-pVTZ level of theory. Properties of the full PES, i.e., stationary points, harmonic frequencies of the global minimum, etc., are shown to be in excellent agreement with direct CCSD(T)-F12b/aug-cc-pVTZ results. Diffusion Monte Carlo calculations of the dimer zero-point energy (ZPE) are performed, and a dissociation energy, D0, of 787 cm-1 is obtained using that ZPE, De, and the rigorous ZPEs of the monomers. Using a benchmark De, D0 is 758 cm-1. Vibrational self-consistent field (VSCF)/virtual state configuration interaction (VCI) MULTIMODE calculations of intramolecular fundamentals are reported and are in good agreement with available experimental results. Finally, the full dimer PES is combined with an existing ab initio water potential to develop a potential for the CO2 hydrate clathrate CO2(H2O)20(512 water cage). A full normal-mode analysis of this hydrate clathrate is reported as are local-monomer VSCF/VCI calculations of the fundamentals of CO2.

Two-component, ab initio potential energy surface for CO2-H2O, extension to the hydrate clathrate, CO2@(H2O)20, and VSCF/VCI vibrational analyses of both.

PubMed

Wang, Qingfeng Kee; Bowman, Joel M

2017-10-28

We report an ab initio, full-dimensional, potential energy surface (PES) for CO 2 -H 2 O, in which two-body interaction energies are fit using a basis of permutationally invariant polynomials and combined with accurate potentials for the non-interacting monomers. This approach which we have termed "plug and play" is extended here to improve the precision of the 2-body fit in the long range. This is done by combining two separate fits. One is a fit to 47 593 2-body energies in the region of strong interaction and approaching the long range, and the second one is a fit to 6244 2-body energies in the long range. The two fits have a region of overlap which permits a smooth switch from one to the other. All energies are obtained at the CCSD(T)-F12b/aug-cc-pVTZ level of theory. Properties of the full PES, i.e., stationary points, harmonic frequencies of the global minimum, etc., are shown to be in excellent agreement with direct CCSD(T)-F12b/aug-cc-pVTZ results. Diffusion Monte Carlo calculations of the dimer zero-point energy (ZPE) are performed, and a dissociation energy, D 0 , of 787 cm -1 is obtained using that ZPE, D e , and the rigorous ZPEs of the monomers. Using a benchmark D e , D 0 is 758 cm -1 . Vibrational self-consistent field (VSCF)/virtual state configuration interaction (VCI) MULTIMODE calculations of intramolecular fundamentals are reported and are in good agreement with available experimental results. Finally, the full dimer PES is combined with an existing ab initio water potential to develop a potential for the CO 2 hydrate clathrate CO 2 (H 2 O) 20 (5 12 water cage). A full normal-mode analysis of this hydrate clathrate is reported as are local-monomer VSCF/VCI calculations of the fundamentals of CO 2 .

Effects of in utero exposure to phthalate plasticizers on reproductive development in rats and possible human health concerns

EPA Science Inventory

Phthalate diesters (PEs) are high-production chemicals used to impart flexibiliyt to pllyvinylchloride products. Humans are ubiquitously exposed to these chemicals. Certain PEs are reporductive toxicants in laboratory rats. This presentation will review the effects and mechanisms...

Task relevance modulates the behavioural and neural effects of sensory predictions

PubMed Central

Friston, Karl J.; Nobre, Anna C.

2017-01-01

The brain is thought to generate internal predictions to optimize behaviour. However, it is unclear whether predictions signalling is an automatic brain function or depends on task demands. Here, we manipulated the spatial/temporal predictability of visual targets, and the relevance of spatial/temporal information provided by auditory cues. We used magnetoencephalography (MEG) to measure participants’ brain activity during task performance. Task relevance modulated the influence of predictions on behaviour: spatial/temporal predictability improved spatial/temporal discrimination accuracy, but not vice versa. To explain these effects, we used behavioural responses to estimate subjective predictions under an ideal-observer model. Model-based time-series of predictions and prediction errors (PEs) were associated with dissociable neural responses: predictions correlated with cue-induced beta-band activity in auditory regions and alpha-band activity in visual regions, while stimulus-bound PEs correlated with gamma-band activity in posterior regions. Crucially, task relevance modulated these spectral correlates, suggesting that current goals influence PE and prediction signalling. PMID:29206225

Bioaccumulation of metals and metalloids in medicinal plant Ipomoea pes-caprae from areas impacted by tsunami.

PubMed

Kozak, Lidia; Kokociński, Mikołaj; Niedzielski, Przemysław; Lorenc, Stanisław

2015-02-01

Tsunami events may have an enormous impact on the functioning of aquatic and terrestrial ecosystems by altering various relationships with biotic components. Concentrations of acid-leachable fractions of heavy metals and metalloids in soils and plant samples from areas affected by the December 2004 tsunami in Thailand were determined. Ipomoea pes-caprae, a common plant species growing along the seashore of this region, and frequently used in folk medicine, was selected to assess the presence of selected elements. Elevated amounts of Cd, Pb, Zn, and As in soil samples, and Pb, Zn, As, Se, Cr, and Ni in plant samples were determined from the tsunami-impacted regions for comparison with reference locations. The flowers of Ipomoea pes-caprae contained the highest amounts of these metals, followed by its leaves, and stems. In addition, its bioaccumulation factor (BAF) supports this capability of high metal uptake by Ipomoea pes-caprae from the areas affected by the tsunami in comparison with a reference site. This uptake was followed by the translocation of these elements to the various plant components. The presence of these toxic metals in Ipomoea pes-caprae growing in contaminated soils should be a concern of those who use this plant for medicinal purposes. Further studies on the content of heavy metals and metalloids in this plant in relation to human health concerns are recommended. © 2014 SETAC.

Randomized, Split-Face/Décolleté Comparative Trial of Procedure Enhancement System for Fractional non-Ablative Laser Resurfacing Treatment.

PubMed

Robinson, Deanne Mraz; Frulla, Ashton P

2017-07-01

INTRODUCTION: A topical proprietary procedural enhancement system (PES) containing a combination of active ingredients including a tripeptide and hexapeptide (TriHex Technology™, Alastin Procedure Enhancement Invasive System, ALASTIN Skincare™, Inc., Carlsbad, CA) has been used successfully to aid in healing and improve symptomatology following resurfacing procedures.

METHODS: PES (Gentle Cleanser, Regenerating Skin Nectar with TriHex Technology™, Ultra Nourishing Moisturizer with TriHex Technology™, Soothe + Protect Recovery Balm, Broad Spectrum 30+ Sunscreen) was compared to a basic regimen (Aquaphor™, Cerave™ cleanser, Vanicream™, Alastin Broad Spectrum 30+ Sunscreen) in a split face/ décolleté trial following fractional non-ablative thulium-doped resurfacing treatment to the face or décolleté. The skin was pre-conditioned and treated during and after the procedure using the two regimens.

RESULTS: A blinded investigator rated the PES statistically superior to the basic regimen on healing post-laser treatment on day 4 based on lentigines, texture, and Global Skin Quality. Subjects also reported 'better looking and feeling' skin on the PES side.

CONCLUSION: PES appears to improve healing post-non ablative thulium-doped resurfacing treatment to the face/décolleté in comparison with standard of care.

J Drugs Dermatol. 2017;16(7):707-710.

Hemocompatibility evaluation of poly(1,8-octanediol citrate) blend polyethersulfone membranes.

PubMed

Zailani, Muhamad Zulhilmi; Ismail, Ahmad Fauzi; Sheikh Abdul Kadir, Siti Hamimah; Othman, Mohd Hafiz Dzarfan; Goh, Pei Sean; Hasbullah, Hasrinah; Abdullah, Mohd Sohaimi; Ng, Be Cheer; Kamal, Fatmawati

2017-05-01

In this study, poly (1,8-octanediol citrate) (POC) was used to modify polyethersulfone (PES)-based membrane to enhance its hemocompatibility. Different compositions of POC (0-3%) were added into the polyethersulfone (PES) dope solutions and polyvinylpyrrolidone (PVP) was used as pore forming agent. The hemocompatible POC modified PES membranes were fabricated through phase-inversion technique. The prepared membranes were characterized using attenuated total reflectance-Fourier transform infrared (ATR-FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Atomic-force microscopy (AFM), contact angle, Zeta-potential, membrane porosity and pore size and pure water flux (PWF) and BSA rejection. The hemocompatibility of the modified PES membranes was evaluated by human serum fibrinogen (FBG) protein adsorption, platelet adhesion, activated partial thromboplastin time (APTT) and prothrombin time (PT), and thrombin-antithrombin III (TAT), complement (C3a and C5a) activation and Ca 2+ absorption on membrane. Results showed that by increasing POC concentration, FBG adsorption was reduced, less platelets adhesion, prolonged APTT and PT, lower TAT, C5a and C3a activation and absorb more Ca 2+ ion. These results indicated that modification of PES with POC has rendered improved hemocompatibility properties for potential application in the field of blood purification, especially in hemodialysis. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1510-1520, 2017. © 2017 Wiley Periodicals, Inc.

Immediate Restoration of Immediate Implants in the Esthetic Zone of the Maxilla Via the Copy-Abutment Technique: 5-Year Follow-Up of Pink Esthetic Scores.

PubMed

Fürhauser, Rudolf; Mailath-Pokorny, Georg; Haas, Robert; Busenlechner, Dieter; Watzek, Georg; Pommer, Bernhard

2017-02-01

Implant esthetics may benefit from individualized zirconia abutments copying the emergence profile of the natural tooth and delivered within days after immediate implant insertion. To investigate the esthetic outcome of the Copy-Abutment technique using the Pink Esthetic Score (PES). A total of 77 patients with single-tooth implants in the anterior maxilla restored at the day of immediate implant placement using Copy-Abutments and provisional crowns were followed-up after 1 week, 1 month, 4 months, 6 months, 1, 2, 3, 4, and 5 years to assess implant esthetics. PES ranged between 7 and 14 (median: 13) and improved significantly between the 6 month and 1 year follow-up (p < .001), then remained stable up to the fifth year. Significant improvement was seen for the variables PES-6 soft tissue color (p = .002) and PES-7 soft tissue texture (p < .001) up to the 1 year follow-up, while PES-5 alveolar process deficiency deteriorated (p = .016). Mean mucosal recession was 0.26 ± 0.86 mm (range: 0-1.6) after 5 years and not related to gingival biotype. Copy-Abutments for immediate restoration of implants in the esthetic zone show satisfactory long-term esthetic outcomes. © 2016 Wiley Periodicals, Inc.

Esthetic Evaluation of Implant Crowns and Peri-Implant Soft Tissue in the Anterior Maxilla: Comparison and Reproducibility of Three Different Indices.

PubMed

Tettamanti, Sandro; Millen, Christopher; Gavric, Jelena; Buser, Daniel; Belser, Urs C; Brägger, Urs; Wittneben, Julia-Gabriela

2016-06-01

A successful implant reconstruction with optimal esthetics consists of a visually pleasing prosthesis and complete and healthy surrounding soft tissue. In the current literature, numerous indices used to qualitatively assess esthetics have been described. However, studies comparing the indices and their reproducibility are scarce. The aim of this study was to compare three different esthetic indices for the evaluation of single implant-supported crowns. A total of 10 prosthodontists (P), 10 orthodontists (O), 10 general dentists (G), and 10 lay people (L) independently performed the same assessment using 30 photographs and corresponding casts with three different esthetic indices (Peri-Implant and Crown Index [PICI], Implant Crown Aesthetic Index [ICAI], "Pink Esthetic Score/White Esthetic Score [PES/WES]) and repeated the evaluations 4 weeks later. The PES/WES and the PICI showed significantly higher esthetic scores (pink, white, total) and clinical acceptance compared with the ICAI in all four groups and in both assessments. The highest intraobserver agreement was achieved using the PES/WES and the least with the ICAI. The mean Kappa per group ranged from 0.18 (group L with ICAI) to 0.63 (group G with PICI). In comparison with the ICAI, the PES/WES and PICI were more reproducible. Therefore, PES/WES and PICI seem to be more suitable as esthetic indices for single implant crowns. © 2015 Wiley Periodicals, Inc.

Lessons from community-based payment for ecosystem service schemes: from forests to rangelands.

PubMed

Dougill, Andrew J; Stringer, Lindsay C; Leventon, Julia; Riddell, Mike; Rueff, Henri; Spracklen, Dominick V; Butt, Edward

2012-11-19

Climate finance investments and international policy are driving new community-based projects incorporating payments for ecosystem services (PES) to simultaneously store carbon and generate livelihood benefits. Most community-based PES (CB-PES) research focuses on forest areas. Rangelands, which store globally significant quantities of carbon and support many of the world's poor, have seen little CB-PES research attention, despite benefitting from several decades of community-based natural resource management (CBNRM) projects. Lessons from CBNRM suggest institutional considerations are vital in underpinning the design and implementation of successful community projects. This study uses documentary analysis to explore the institutional characteristics of three African community-based forest projects that seek to deliver carbon-storage and poverty-reduction benefits. Strong existing local institutions, clear land tenure, community control over land management decision-making and up-front, flexible payment schemes are found to be vital. Additionally, we undertake a global review of rangeland CBNRM literature and identify that alongside the lessons learned from forest projects, rangeland CB-PES project design requires specific consideration of project boundaries, benefit distribution, capacity building for community monitoring of carbon storage together with awareness-raising using decision-support tools to display the benefits of carbon-friendly land management. We highlight that institutional analyses must be undertaken alongside improved scientific studies of the carbon cycle to enable links to payment schemes, and for them to contribute to poverty alleviation in rangelands.

Lessons from community-based payment for ecosystem service schemes: from forests to rangelands

PubMed Central

Dougill, Andrew J.; Stringer, Lindsay C.; Leventon, Julia; Riddell, Mike; Rueff, Henri; Spracklen, Dominick V.; Butt, Edward

2012-01-01

Climate finance investments and international policy are driving new community-based projects incorporating payments for ecosystem services (PES) to simultaneously store carbon and generate livelihood benefits. Most community-based PES (CB-PES) research focuses on forest areas. Rangelands, which store globally significant quantities of carbon and support many of the world's poor, have seen little CB-PES research attention, despite benefitting from several decades of community-based natural resource management (CBNRM) projects. Lessons from CBNRM suggest institutional considerations are vital in underpinning the design and implementation of successful community projects. This study uses documentary analysis to explore the institutional characteristics of three African community-based forest projects that seek to deliver carbon-storage and poverty-reduction benefits. Strong existing local institutions, clear land tenure, community control over land management decision-making and up-front, flexible payment schemes are found to be vital. Additionally, we undertake a global review of rangeland CBNRM literature and identify that alongside the lessons learned from forest projects, rangeland CB-PES project design requires specific consideration of project boundaries, benefit distribution, capacity building for community monitoring of carbon storage together with awareness-raising using decision-support tools to display the benefits of carbon-friendly land management. We highlight that institutional analyses must be undertaken alongside improved scientific studies of the carbon cycle to enable links to payment schemes, and for them to contribute to poverty alleviation in rangelands. PMID:23045714

[Inherited metabolic disorders in pediatric emergency services].

PubMed

Molina Gutiérrez, M A; López López, R; Morais López, A; Bueno Barriocanal, M; Martínez Ojinaga Nodal, E; Alcolea Sánchez, A M; García García, S

2015-06-01

Advances in the early diagnosis and treatment have led to improved survival, and a better quality of life for patients with inherited metabolic disorders (IMD). They can go to the Pediatric Emergency Services (PES) for reasons unrelated to their disease. The purpose of this study was to review the characteristics of visitors to the PES of these patients in a tertiary hospital. A retrospective observational study was conducted on all visits from patients with IMD to the PES of Hospital Infantil La Paz over the years 2011 and 2012. IMD type, complaint, duration of symptoms, need for hospitalization, and presence of metabolic decompensation was recorded. A total of 107 visits were analyzed, with the most frequent reason being for consultation of respiratory processes (30.8%). When the consultation was for vomiting, patients with protein-related disorders were those who delayed less in going to PES. One third of visitors were admitted, half of them due to metabolic decompensation of the underlying pathology. Patients with IMD came to PES for many different reasons, which in some cases were the cause or consequence of an acute metabolic decompensation that led to hospitalization. Being diseases with low prevalence, it would be useful to have diagnostic and therapeutic protocols in order to provide optimal care. Copyright © 2014 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

Isolation and characterization of a carrot nucleolar protein with structural and sequence similarity to the vertebrate PESCADILLO protein.

PubMed

Ueda, Kenji; Xu, Zheng-Jun; Miyagi, Nobuaki; Ono, Michiyuki; Wabiko, Hiroetsu; Masuda, Kiyoshi; Inoue, Masayasu

2013-07-01

The nuclear matrix is involved in many nuclear events, but its protein architecture in plants is still not fully understood. A cDNA clone was isolated by immunoscreening with a monoclonal antibody raised against nuclear matrix proteins of Daucus carota L. Its deduced amino acid sequence showed about 40% identity with the PESCADILLO protein of zebrafish and humans. Primary structure analysis of the protein revealed a Pescadillo N-terminus domain, a single breast cancer C-terminal domain, two nuclear localization signals, and a potential coiled-coil region as also found in animal PESCADILLO proteins. Therefore, we designated this gene DcPES1. Although DcPES1 mRNA was detected in all tissues examined, its levels were highest in tissues with proliferating cells. Immunofluorescence using specific antiserum against the recombinant protein revealed that DcPES1 localized exclusively in the nucleolus. Examination of fusion proteins with green fluorescent protein revealed that the N-terminal portion was important for localization to the nucleoli of tobacco and onion cells. Moreover, when the nuclear matrix of carrot cells was immunostained with an anti-DcPES1 serum, the signal was detected in the nucleolus. Therefore, the DcPES1 protein appears to be a component of or tightly bound to components of the nuclear matrix. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Percent Stomach Emptiness in Fish Collections: Sources of Variation and Study Design Implications

EPA Science Inventory

We summarized fish stomach content data from 369,000 fish from 402 species in 1,096 collections made between 1925 and 2009 and report on the percentage of individuals with empty stomachs (PES). The mean PES among all species, locations, habitats, dates, and collection methods was...

Reliability study of tibialis posterior and selected leg muscle EMG and multi-segment foot kinematics in rheumatoid arthritis associated pes planovalgus

PubMed Central

Barn, Ruth; Rafferty, Daniel; Turner, Deborah E.; Woodburn, James

2012-01-01

Objective To determine within- and between-day reliability characteristics of electromyographic (EMG) activity patterns of selected lower leg muscles and kinematic variables in patients with rheumatoid arthritis (RA) and pes planovalgus. Methods Five patients with RA underwent gait analysis barefoot and shod on two occasions 1 week apart. Fine-wire (tibialis posterior [TP]) and surface EMG for selected muscles and 3D kinematics using a multi-segmented foot model was undertaken barefoot and shod. Reliability of pre-determined variables including EMG activity patterns and inter-segment kinematics were analysed using coefficients of multiple correlation, intraclass correlation coefficients (ICC) and the standard error of the measurement (SEM). Results Muscle activation patterns within- and between-day ranged from fair-to-good to excellent in both conditions. Discrete temporal and amplitude variables were highly variable across all muscle groups in both conditions but particularly poor for TP and peroneus longus. SEMs ranged from 1% to 9% of stance and 4% to 27% of maximum voluntary contraction; in most cases the 95% confidence interval crossed zero. Excellent within-day reliability was found for the inter-segment kinematics in both conditions. Between-day reliability ranged from fair-to-good to excellent for kinematic variables and all ICCs were excellent; the SEM ranged from 0.60° to 1.99°. Conclusion Multi-segmented foot kinematics can be reliably measured in RA patients with pes planovalgus. Serial measurement of discrete variables for TP and other selected leg muscles via EMG is not supported from the findings in this cohort of RA patients. Caution should be exercised when EMG measurements are considered to study disease progression or intervention effects. PMID:22721819

Pressure broadening of the electric dipole and Raman lines of CO2 by argon: Stringent test of the classical impact theory at different temperatures on a benchmark system

NASA Astrophysics Data System (ADS)

Ivanov, Sergey V.; Buzykin, Oleg G.

2016-12-01

A classical approach is applied to calculate pressure broadening coefficients of CO2 vibration-rotational spectral lines perturbed by Ar. Three types of spectra are examined: electric dipole (infrared) absorption; isotropic and anisotropic Raman Q branches. Simple and explicit formulae of the classical impact theory are used along with exact 3D Hamilton equations for CO2-Ar molecular motion. The calculations utilize vibrationally independent most accurate ab initio potential energy surface (PES) of Hutson et al. expanded in Legendre polynomial series up to lmax = 24. New improved algorithm of classical rotational frequency selection is applied. The dependences of CO2 half-widths on rotational quantum number J up to J=100 are computed for the temperatures between 77 and 765 K and compared with available experimental data as well as with the results of fully quantum dynamical calculations performed on the same PES. To make the picture complete, the predictions of two independent variants of the semi-classical Robert-Bonamy formalism for dipole absorption lines are included. This method. however, has demonstrated poor accuracy almost for all temperatures. On the contrary, classical broadening coefficients are in excellent agreement both with measurements and with quantum results at all temperatures. The classical impact theory in its present variant is capable to produce quickly and accurately the pressure broadening coefficients of spectral lines of linear molecules for any J value (including high Js) using full-dimensional ab initio - based PES in the cases where other computational methods are either extremely time consuming (like the quantum close coupling method) or give erroneous results (like semi-classical methods).

Development of a living membrane comprising a functional human renal proximal tubule cell monolayer on polyethersulfone polymeric membrane.

PubMed

Schophuizen, Carolien M S; De Napoli, Ilaria E; Jansen, Jitske; Teixeira, Sandra; Wilmer, Martijn J; Hoenderop, Joost G J; Van den Heuvel, Lambert P W; Masereeuw, Rosalinde; Stamatialis, Dimitrios

2015-03-01

The need for improved renal replacement therapies has stimulated innovative research for the development of a cell-based renal assist device. A key requirement for such a device is the formation of a "living membrane", consisting of a tight kidney cell monolayer with preserved functional organic ion transporters on a suitable artificial membrane surface. In this work, we applied a unique conditionally immortalized proximal tubule epithelial cell (ciPTEC) line with an optimized coating strategy on polyethersulfone (PES) membranes to develop a living membrane with a functional proximal tubule epithelial cell layer. PES membranes were coated with combinations of 3,4-dihydroxy-l-phenylalanine and human collagen IV (Coll IV). The optimal coating time and concentrations were determined to achieve retention of vital blood components while preserving high water transport and optimal ciPTEC adhesion. The ciPTEC monolayers obtained were examined through immunocytochemistry to detect zona occludens 1 tight junction proteins. Reproducible monolayers were formed when using a combination of 2 mg ml(-1) 3,4-dihydroxy-l-phenylalanine (4 min coating, 1h dissolution) and 25 μg ml(-1) Coll IV (4 min coating). The successful transport of (14)C-creatinine through the developed living membrane system was used as an indication for organic cation transporter functionality. The addition of metformin or cimetidine significantly reduced the creatinine transepithelial flux, indicating active creatinine uptake in ciPTECs, most likely mediated by the organic cation transporter, OCT2 (SLC22A2). In conclusion, this study shows the successful development of a living membrane consisting of a reproducible ciPTEC monolayer on PES membranes, an important step towards the development of a bioartificial kidney. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Differential and integral cross sections for the rotationally inelastic scattering of methyl radicals with H2 and D2

NASA Astrophysics Data System (ADS)

Tkáč, Ondřej; Ma, Qianli; Rusher, Cassandra A.; Greaves, Stuart J.; Orr-Ewing, Andrew J.; Dagdigian, Paul J.

2014-05-01

Comparisons are presented of experimental and theoretical studies of the rotationally inelastic scattering of CD3 radicals with H2 and D2 collision partners at respective collision energies of 680 ± 75 and 640 ± 60 cm-1. Close-coupling quantum-mechanical calculations performed using a newly constructed ab initio potential energy surface (PES) provide initial-to-final CD3 rotational level (n, k → n', k') integral and differential cross sections (ICSs and DCSs). The DCSs are compared with crossed molecular beam and velocity map imaging measurements of angular scattering distributions, which serve as a critical test of the accuracy of the new PES. In general, there is very good agreement between the experimental measurements and the calculations. The DCSs for CD3 scattering from both H2 and D2 peak in the forward hemisphere for n' = 2-4 and shift more to sideways and backward scattering for n' = 5. For n' = 6-8, the DCSs are dominated by backward scattering. DCSs for a particular CD3 n → n' transition have a similar angular dependence with either D2 or H2 as collision partner. Any differences between DCSs or ICSs can be attributed to mass effects because the PES is unchanged for CD3-H2 and CD3-D2 collisions. Further comparisons are drawn between the CD3-D2 scattering and results for CD3-He presented in our recent paper [O. Tkáč, A. G. Sage, S. J. Greaves, A. J. Orr-Ewing, P. J. Dagdigian, Q. Ma, and M. H. Alexander, Chem. Sci. 4, 4199 (2013)]. These systems have the same reduced mass, but are governed by different PESs.

Microhydration Effects on the Intermediates of the SN2 Reacation of Iodide Anion with Methyl Iodine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doi, Keisuke; Togano, Eijiro; Xantheas, Sotiris S.

2013-04-15

Reactions of halide anions with methyl halides (X- + CH3Y → XCH3 + Y-) are bimolecular nucleophilic substitution (SN2) reactions that have been well investigated in the last few decades.[1] Figure 1 shows typical potential energy surfaces (PESs) proposed for symmetric (X- + CH3X → XCH3 + X-) SN2 reactions along the reaction coordinate. In the gas phase, the PES has two minima corresponding to the stable X-(CH3X) complexes.[2] The PES is substantially distorted by the solvation. Since the negative charge is delocalized over the [X•••CH3•••X]- moiety at the transition state the stabilization energy gained by the solvation is smallermore » for the transition state than that for the (X- + CH3X) reactants or the X- (CH3X) complexes. In solution, a large potential barrier exists between the reactants and products. The rate constants of these reactions in protic solvents were reported to be a few orders of magnitude smaller than those in aprotic solvents; this trend was explained by the formation of solvation shells of protic molecules around the halide anions.[1,3] Morokuma has previously reported a theoretical study on the PES of the (Cl- + CH3Cl → ClCH3 + Cl-) SN2 reaction with a few H2O molecules. The attachment of H2O molecules to the Cl-(CH3Cl) reactive system produces metastable isomers, which affect the reaction mechanism.[4] Johnson and coworkers extensively investigated the structure and reactions of halide anion complexes in the gas phase using photodissociation spectroscopy.« less

Nucleophilic substitution at phosphorus centers (SN2@p).

PubMed

van Bochove, Marc A; Swart, Marcel; Bickelhaupt, F Matthias

2007-12-03

We have studied the characteristics of archetypal model systems for bimolecular nucleophilic substitution at phosphorus (SN2@P) and, for comparison, at carbon (SN2@C) and silicon (SN2@Si) centers. In our studies, we applied the generalized gradient approximation (GGA) of density functional theory (DFT) at the OLYP/TZ2P level. Our model systems cover nucleophilic substitution at carbon in X(-)+CH3Y (SN2@C), at silicon in X(-)+SiH3Y (SN2@Si), at tricoordinate phosphorus in X(-)+PH2Y (SN2@P3), and at tetracoordinate phosphorus in X(-)+POH2Y (SN2@P4). The main feature of going from SN2@C to SN2@P is the loss of the characteristic double-well potential energy surface (PES) involving a transition state [X--CH3--Y]- and the occurrence of a single-well PES with a stable transition complex, namely, [X--PH2--Y]- or [X--POH2--Y](-). The differences between SN2@P3 and SN2@P4 are relatively small. We explored both the symmetric and asymmetric (i.e. X, Y=Cl, OH) SN2 reactions in our model systems, the competition between backside and frontside pathways, and the dependence of the reactions on the conformation of the reactants. Furthermore, we studied the effect, on the symmetric and asymmetric SN2@P3 and S(N)2@P4 reactions, of replacing hydrogen substituents at the phosphorus centers by chlorine and fluorine in the model systems X(-)+PR2Y and X(-)+POR2Y, with R=Cl, F. An interesting phenomenon is the occurrence of a triple-well PES not only in the symmetric, but also in the asymmetric SN2@P4 reactions of X(-)+POCl2--Y.

Electrons as probes of dynamics in molecules and clusters: A contribution from Time Dependent Density Functional Theory

NASA Astrophysics Data System (ADS)

Wopperer, P.; Dinh, P. M.; Reinhard, P.-G.; Suraud, E.

2015-02-01

There are various ways to analyze the dynamical response of clusters and molecules to electromagnetic perturbations. Particularly rich information can be obtained from measuring the properties of electrons emitted in the course of the excitation dynamics. Such an analysis of electron signals covers observables such as total ionization, Photo-Electron Spectra (PES), Photoelectron Angular Distributions (PAD), and ideally combined PES/PAD. It has a long history in molecular physics and was increasingly used in cluster physics as well. Recent progress in the design of new light sources (high intensity, high frequency, ultra short pulses) opens new possibilities for measurements and thus has renewed the interest on these observables, especially for the analysis of various dynamical scenarios, well beyond a simple access to electronic density of states. This, in turn, has motivated many theoretical investigations of the dynamics of electronic emission for molecules and clusters up to such a complex and interesting system as C60. A theoretical tool of choice is here Time-Dependent Density Functional Theory (TDDFT) propagated in real time and on a spatial grid, and augmented by a Self-Interaction Correction (SIC). This provides a pertinent, robust, and efficient description of electronic emission including the detailed pattern of PES and PAD. A direct comparison between experiments and well founded elaborate microscopic theories is thus readily possible, at variance with more demanding observables such as for example fragmentation or dissociation cross sections. The purpose of this paper is to describe the theoretical tools developed on the basis of real-time and real-space TDDFT and to address in a realistic manner the analysis of electronic emission following irradiation of clusters and molecules by various laser pulses. After a general introduction, we shall present in a second part the available experimental results motivating such studies, starting from the simplest total ionization signals to the more elaborate PES and PAD, possibly combining them and/or resolving them in time. This experimental discussion will be complemented in a third part by a presentation of available theoretical tools focusing on TDDFT and detailing the methods used to address ionization observables. We shall also discuss the shortcomings of standard versions of TDDFT, especially what concerns the SIC problem, and show how to improve formally and practically the theory on that aspect. A long fourth part will be devoted to representative results. We shall illustrate the use of total ionization in pump and probe scenarios with fs lasers for tracking ionic dynamics in clusters. More challenging from the experimental point of view is pump and probe setups using attosecond pulses. The effort there is more on the capability to define proper signals to be measured/computed at such a short time scale. TDDFT analysis provides here a valuable tool in the search for the most efficient observables. PES and PAD will allow one to address more directly electronic dynamics itself by means of fs or ns laser pulses. We shall in particular discuss the impact of the dynamical regime in PES and PAD. We shall end this fourth part by addressing the role of temperature in PES and PAD. When possible, the results will be directly compared to experiments. The fifth part of the paper will be devoted to future directions of investigations. From the rich choice of developments, we shall in particular address two aspects. We shall start to discuss the information content of energy/angular spectra of emitted electrons in case of excitation by swift and highly charged ions rather than lasers. The second issue concerns the account of dissipative effects in TDDFT to be able to consider longer laser pulses where the competition between direct electron emission and thermalization is known to play a role as, e.g., in experiments with C60. Although such questions have been superficially addressed in the simple case of alkaline clusters by means of semi-classical methods, no satisfying quantum formulation, compulsory for most realistic systems, is yet available. First encouraging results will be presented on that occasion. We shall finally give a short conclusion.

Implementation of a Values Training Program in Physical Education and Sport: A Follow-Up Study

ERIC Educational Resources Information Center

Koh, Koon Teck; Camiré, Martin; Lim Regina, Si Hui; Soon, Woo Sin

2017-01-01

Background: There is growing evidence indicating that physical education and sport (PES) are environments that, when appropriately structured, can promote positive youth developmental outcomes. In recent years, a number of researchers working in PES have designed programs and interventions aimed at helping teachers and coaches teach life skills…

Peer Education from the Perspective of Peer Educators

ERIC Educational Resources Information Center

Karaca, Aysel; Akkus, Dilek; Sener, Dilek Konuk

2018-01-01

Peer educators (PEs) have a significant role in providing education on various health issues like smoking, alcohol, and other substance use. This study aimed to determine the experiences and opinions of PEs regarding a peer education program. Using the qualitative research method, data were collected from the study sample, which consisted of 23…