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1

Rheological Behaviour of Wheat Glutens at Small and Large Deformations. Comparison of Two Glutens Differing in Bread Making Potential  

Microsoft Academic Search

The rheological characteristics of hydrated cv. Obelisk and Katepwa glutens, with poor and good baking potential, respectively, were studied at small and large deformations. Dynamic (oscillatory) measurements at small deformations over a frequency range of 0·03 to 3 rad\\/s showed that cv. Katepwa gluten had a higher dynamic modulus and a lower loss tangent than cv. Obelisk gluten. Overmixing resulted

A. M. Janssen; T. van Vliet; J. M. Vereijken

1996-01-01

2

Discussion on the Energy-Saving Potential of a Hybrid System in a Large Space Building in Different Areas  

E-print Network

. An industrial factory was provided with the hybrid ventilation system using different weather conditions in three typical areas-Beijing, Shanghai and Guangzhou-to determine the energy-saving potential in different areas. The results of research in this paper...

Liu, S.; Huang, C.

2006-01-01

3

Modeling emf, Potential Difference, and Internal Resistance  

NSDL National Science Digital Library

Through class discussion and think-pair-share questions, this activity helps students come to understand the difference between emf and potential difference in electrical circuits. These concepts are broached within the context of internal resistance of batteries.

Steven Maier

4

Large data analysis of different sensory modalities  

NASA Astrophysics Data System (ADS)

We exam the historical remote digital video and in situ analog acoustic data analyses from the modern Large Data Analysis standpoint. We discussed a potential automation from traditional search engine to modern one. We exam the mathematic theory to answer where the nonlinear dimensional analysis assume a local flat space where linear eigenvalue provided the independent components, then the component is extrapolated to original nonlinear space and assume the local flat reduction remains meaningful at global nonlinear domain.

Hsu, Ming-Kai; Szu, Harold

2014-05-01

5

On the Potential of Large Ring Lasers  

E-print Network

We describe a new ring laser with area A = 833 m^2 and update performance statistics for several such machines. Anandan & Chaio 1982 judged ring lasers inferior to matter interferometers as possible detectors of gravitational waves. However, we note that geophysically interesting results have been obtained from large ring lasers and that there is still a lot of room for improvements.

G. E. Stedman; R. B. Hurst; K. U. Schreiber

2007-07-10

6

Reflectionless potentials for difference Schrödinger equations  

NASA Astrophysics Data System (ADS)

As a part of the program ‘discrete quantum mechanics’, we present general reflectionless potentials for difference Schrödinger equations with pure imaginary shifts. By combining contiguous integer wave number reflectionless potentials, we construct the discrete analogues of the h(h+1)/{{cosh }2}x potential with the integer h, which belong to the recently constructed families of solvable dynamics having the q-ultraspherical polynomials with |q|=1 as the main part of the eigenfunctions. For the general (h\\in {{{R}}\\gt 0}) scattering theory for these potentials, we need the connection formulas for the basic hypergeometric function 2{{? }1}?ft( \\begin{array}{ccccccccccccccc} a,b \\\\ c \\\\ \\end{array}|qz \\right) with |q|=1, which is not known. The connection formulas are expected to contain the quantum dilogarithm functions as the |q|=1 counterparts of the q-gamma functions. We propose a conjecture of the connection formula of the 2{{? }1} function with |q|=1. Based on the conjecture, we derive the transmission and reflection amplitudes, which have all the desirable properties. They provide a strong support to the conjectured connection formula.

Odake, Satoru; Sasaki, Ryu

2015-03-01

7

Lichtheimia Species Exhibit Differences in Virulence Potential  

PubMed Central

Although the number of mucormycosis cases has increased during the last decades, little is known about the pathogenic potential of most mucoralean fungi. Lichtheimia species represent the second and third most common cause of mucormycosis in Europe and worldwide, respectively. To date only three of the five species of the genus have been found to be involved in mucormycosis, namely L. corymbifera, L. ramosa and L. ornata. However, it is not clear whether the clinical situation reflects differences in virulence between the species of Lichtheimia or whether other factors are responsible. In this study the virulence of 46 strains of all five species of Lichtheimia was investigated in chicken embryos. Additionally, strains of the closest-related genus Dichotomocladium were tested. Full virulence was restricted to the clinically relevant species while all strains of L. hyalospora, L. sphaerocystis and Dichotomocladium species were attenuated. Although virulence differences were present in the clinically relevant species, no connection between origin (environmental vs clinical) or phylogenetic position within the species was observed. Physiological studies revealed no clear connection of stress resistance and carbon source utilization with the virulence of the strains. Slower growth at 37°C might explain low virulence of L. hyalospora, L. spaherocystis and Dichotomocladium; however, similarly slow growing strains of L. ornata were fully virulent. Thus, additional factors or a complex interplay of factors determines the virulence of strains. Our data suggest that the clinical situation in fact reflects different virulence potentials in the Lichtheimiaceae. PMID:22911715

Schwartze, Volker U.; Hoffmann, Kerstin; Nyilasi, Ildikó; Papp, Tamás; Vágvölgyi, Csaba; de Hoog, Sybren; Voigt, Kerstin; Jacobsen, Ilse D.

2012-01-01

8

Inversion of potential fields on nodes for large grids  

NASA Astrophysics Data System (ADS)

The non-iterative direct inversion of potential field data by stochastic approach enables to incorporate in a coherent way a priori geological knowledge, the known densities on any support size and the gravity data. The weakness of the method is the necessary computation of the parameter covariance matrix. For a large mesh made of prisms, the matrix is simply too large to fit in memory. The new approach approximates the prism covariance matrix by a surrogate matrix computed from the covariance matrix of a reduced set of nodes aimed at representing the whole domain of inversion. Care is taken to preserve the properties of direct stochastic inversion on the whole set of prisms. Hence, the approach accounts in a consistent way for the support effect, the inversion remains exact in the absence of noise on data, point and block known densities are exactly reproduced, any set of linear constraints can be applied, and the inversion is non-iterative in all cases. It is shown on synthetic examples that the number of nodes needs not to be very large to ensure a good approximation of the parameter covariance matrix or to ensure similarity of the inversion solutions. An application to a gravity survey including borehole density data shows the applicability of the method for a large number of cells in the inversion domain. Even with as much as 10,000 nodes and one million prisms, the computing time remained acceptable at less than two hours on a workstation. The inverted solution obtained with the nodes approach is compared to a direct kriging of borehole density data and to direct inversion using only the gravity data. The solution combining both information is different from the inversion using only gravity, but only in the area where borehole data are numerous. Although shown for the gravity-density potential, the approach is general and can be extended to magnetic-susceptibility and joint inversion. The proposed approach helps solving the recurrent problem of the application of stochastic inversion to large grids.

Marcotte, Denis; Shamsipour, Pejman; Coutant, Olivier; Chouteau, Michel

2014-11-01

9

Resolvent estimates for perturbations by large magnetic potentials  

SciTech Connect

We prove optimal high-frequency resolvent estimates for self-adjoint operators of the form G = ?? + ib(x) · ? + i? · b(x) + V(x) on L{sup 2}(R{sup n}), n ? 3, where b(x) and V(x) are large magnetic and electric potentials, respectively. No continuity of the magnetic potential is assumed.

Cardoso, Fernando, E-mail: fernando@dmat.ufpe.br; Cuevas, Claudio, E-mail: cch@dmat.ufpe.br [Departamento de Matemática, Universidade Federal de Pernambuco, CEP. 50540-740 Recife-Pe (Brazil)] [Departamento de Matemática, Universidade Federal de Pernambuco, CEP. 50540-740 Recife-Pe (Brazil); Vodev, Georgi, E-mail: vodev@math.univ-nantes.fr [Département de Mathématiques, Université de Nantes, UMR 6629 du CNRS, 2, rue de la Houssinière, BP 92208, 44332 Nantes Cedex 03 (France)] [Département de Mathématiques, Université de Nantes, UMR 6629 du CNRS, 2, rue de la Houssinière, BP 92208, 44332 Nantes Cedex 03 (France)

2014-02-15

10

Exploiting the Potential Differences in Pasture Grasses  

Technology Transfer Automated Retrieval System (TEKTRAN)

Temperate grasses grown for pasture in Wisconsin exhibit a range of chemical and physical characteristics that influence their utilization by grazing cattle. Potential intake of all grasses declines with maturity due to decreasing cell wall digestiblity, but the leaves and stems of orchardgrass and...

11

Jaw and Long Bone Marrows Have a Different Osteoclastogenic Potential  

PubMed Central

Osteoclasts, the multinucleated bone-resorbing cells, arise through fusion of precursors from the myeloid lineage. However, not all osteoclasts are alike; osteoclasts at different bone sites appear to differ in numerous respects. We investigated whether bone marrow cells obtained from jaw and long bone differed in their osteoclastogenic potential. Bone marrow cells from murine mandible and tibiae were isolated and cultured for 4 and 6 days on plastic or 6 and 10 days on dentin. Osteoclastogenesis was assessed by counting the number of TRAP+ multinucleated cells. Bone marrow cell composition was analyzed by FACS. The expression of osteoclast- and osteoclastogenesis-related genes was studied by qPCR. TRAP activity and resorptive activity of osteoclasts were measured by absorbance and morphometric analyses, respectively. At day 4 more osteoclasts were formed in long bone cultures than in jaw cultures. At day 6 the difference in number was no longer observed. The jaw cultures, however, contained more large osteoclasts on plastic and on dentin. Long bone marrow contained more osteoclast precursors, in particular the myeloid blasts, and qPCR revealed that the RANKL:OPG ratio was higher in long bone cultures. TRAP expression was higher for the long bone cultures on dentin. Although jaw osteoclasts were larger than long bone osteoclasts, no differences were found between their resorptive activities. In conclusion, bone marrow cells from different skeletal locations (jaw and long bone) have different dynamics of osteoclastogenesis. We propose that this is primarily due to differences in the cellular composition of the bone site-specific marrow. PMID:20862464

de Souza Faloni, Ana Paula; Schoenmaker, Ton; Azari, Azin; Katchburian, Eduardo; Cerri, Paulo S.; de Vries, Teun J.

2010-01-01

12

Estimation of flash flood potential for large areas  

Microsoft Academic Search

A methodology for determining the potential for flash floods in small basins within large geographical areas is presented. Geographical Information Systems (GIS) technology is used to assimilate digital spatial data, remotely sensed data, with physically-based hydrologic-hydraulic models of catchment response. The methodology uses digital terrain elevation data, digital river reach data, and the US Geological Survey land- use and land-cover

KONSTANTINE P. GEORGAKAKOS; ALEXANDRE K. GUETTER; JASON A. SPERFSLAGE

1997-01-01

13

NUMERICAL CALIBRATION OF ELECTRIC POTENTIAL DIFFERENCE FOR CRACK SIZE MONITORING  

Microsoft Academic Search

The electric potential difference technique is frequently used to monitor crack size propagation in fatigue testing. Crack size is indirectly measured by the change of the electrical field, due to the crack discontinuity, when the component on test is exposed to an electric current flowing through it. The potential difference can be related to crack size through experimental, analytical or

R. A. CLÁUDIO; C. M. BRANCO

14

Different mechanisms for dynamical arrest in largely asymmetric binary mixtures  

NASA Astrophysics Data System (ADS)

Using confocal microscopy we investigate binary colloidal mixtures with large size asymmetry, in particular the formation of dynamically arrested states of the large spheres. The volume fraction of the system is kept constant, and as the concentration of small spheres is increased we observe a series of transitions of the large spheres to different arrested states: an attractive glass, a gel, and an asymmetric glass. These states are distinguished by the degree of dynamical arrest and the amount of structural and dynamical heterogeneity. The transitions between two different arrested states occur through melting and the formation of a fluid state. While a space-spanning network of bonded particles is found in both arrested and fluid states, only arrested states are characterized by the presence of a space-spanning network of dynamically arrested particles.

Hendricks, J.; Capellmann, R.; Schofield, A. B.; Egelhaaf, S. U.; Laurati, M.

2015-03-01

15

Delayed difference scheme for large scale scientific simulations.  

PubMed

We argue that the current heterogeneous computing environment mimics a complex nonlinear system which needs to borrow the concept of time-scale separation and the delayed difference approach from statistical mechanics and nonlinear dynamics. We show that by replacing the usual difference equations approach by a delayed difference equations approach, the sequential fraction of many scientific computing algorithms can be substantially reduced. We also provide a comprehensive theoretical analysis to establish that the error and stability of our scheme is of the same order as existing schemes for a large, well-characterized class of problems. PMID:25479526

Mudigere, Dheevatsa; Sherlekar, Sunil D; Ansumali, Santosh

2014-11-21

16

Contribution potential of glaciers to water availability in different climate regimes  

E-print Network

Contribution potential of glaciers to water availability in different climate regimes Georg Kaser missing, considerable detrimen- tal changes due to shrinking glaciers are universally expected for water the contribution potential of seasonally delayed glacier melt water to total water availability in large river

Marzeion, Ben

17

Central ridge of Newfoundland: Little explored, potential large  

SciTech Connect

The Central ridge on the northeastern Grand Banks off Newfoundland represents a large area with known hydrocarbon accumulations and the potential for giant fields. It covers some 17,000 sq km with water less than 400 m deep. The first major hydrocarbon discovery on the Newfoundland Grand Banks is giant Hibernia field in the Jeanne d'Arc basin. Hibernia field, discovered in 1979, has reserves of 666 million bbl and is due onstream in 1997. Since Hibernia, 14 other discoveries have been made on the Grand Banks, with three on the Central ridge. Oil was first discovered on Central Ridge in 1980 with the Mobil et al. South Tempest G-88 well. In 1982 gas was discovered with the Mobil et al. North Dana I-43 well 30 km northeast of the earlier discovery. In 1983 gas and condensate were discovered with the Husky-Bow Valley et al. Trave E-87 well 20 km south of the South Tempest well. These discoveries are held under significant discovery licenses and an additional 2,400 sq km are held under exploration licenses. The paper discusses the history of the basin, the reservoir source traps, and the basin potential.

Silva, N.R. De (Canada-Newfoundland Offshore Petroleum Board, Newfoundland, St. Johns (Canada))

1993-10-25

18

A Methodology for Estimating Large-Customer Demand Response MarketPotential  

SciTech Connect

Demand response (DR) is increasingly recognized as an essential ingredient to well-functioning electricity markets. DR market potential studies can answer questions about the amount of DR available in a given area and from which market segments. Several recent DR market potential studies have been conducted, most adapting techniques used to estimate energy-efficiency (EE) potential. In this scoping study, we: reviewed and categorized seven recent DR market potential studies; recommended a methodology for estimating DR market potential for large, non-residential utility customers that uses price elasticities to account for behavior and prices; compiled participation rates and elasticity values from six DR options offered to large customers in recent years, and demonstrated our recommended methodology with large customer market potential scenarios at an illustrative Northeastern utility. We observe that EE and DR have several important differences that argue for an elasticity approach for large-customer DR options that rely on customer-initiated response to prices, rather than the engineering approaches typical of EE potential studies. Base-case estimates suggest that offering DR options to large, non-residential customers results in 1-3% reductions in their class peak demand in response to prices or incentive payments of $500/MWh. Participation rates (i.e., enrollment in voluntary DR programs or acceptance of default hourly pricing) have the greatest influence on DR impacts of all factors studied, yet are the least well understood. Elasticity refinements to reflect the impact of enabling technologies and response at high prices provide more accurate market potential estimates, particularly when arc elasticities (rather than substitution elasticities) are estimated.

Goldman, Charles; Hopper, Nicole; Bharvirkar, Ranjit; Neenan,Bernie; Cappers,Peter

2007-08-01

19

On hemispheric differences in evoked potentials to speech stimuli  

NASA Technical Reports Server (NTRS)

Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

1975-01-01

20

Assessing carbon dynamics in semiarid ecosystems : Balancing potential gains with potential large rapid losses  

SciTech Connect

Photosynthesis and respiration are the largest fluxes into and out of the biosphere (Molles 1999). Consequently, small changes in these fluxes can potentially produce large changes in the storage of carbon in the biosphere. Terrestrial carbon fluxes account for more than half of the carbon transferred between the atmosphere and the earth's surface (about 120 GigaTons/year), and current stores of carbon in terrestrial ecosystem are estimated at 2060 GigaTons. Increasing attention is being focused on the role of managing and sequestering carbon in the terrestrial biosphere as a means for addressing global climate change (IGBP, 1998; U.S. Department of Energy, 1999). Terrestrial ecosystems are widely recognized as a major biological scrubber for atmosphereic CO{sub 2} and their ability to finction as such can be increased significantly over the next 25 years through careful manipulation. The potential for terrestrial carbon gains has been the subject of much attention (Dixon et al., 1994; Masera et al. 1997; Cao and Woodward, 1998; DeLucia et al. 1999). In contrast to other strategies for reducing net carbon emissions, terrestrial sequestration has the potential for rapid implementation. Strategies that focus on soil carbon are likely to be effective because in addition to being a storage pool of carbon, soil carbon also improves site productivity through improving soil quality (e.g., water retention and nutrient availability). The carbon pool in soils is immense and highly dynamic. The flux of carbon into and out of soils is one of the largest uncertainties in the total mass balance of global carbon (NRC, 1999; La1 et al., 1998; Cambardella, 1998). Reducing these uncertainties is key to developing carbon sequestration strategies. Soil carbon pools have been greatly depleted over recent centuries, and there is potential to increase storage of carbon in these soils through effective land management. Whereas carbon in vegetation can be managed directly through land use, carbon in soils generally must be managed indirectly through manipulation of vegetation and nutrients. Land management as well as climate changes have the potential to increase soil carbon, but also could trigger large soil carbon losses. Recently, the importance of accounting for countervailing losses in assessing potential amounts of terrestrial carbon that can be sequestered has been highlighted (Schlesinger, 1999; Walker et al., 1999). Realistic assessment of terrestrial carbon sequestration strategies must consider net results of an applied strategy, not simply projected carbon gains. In addition, large, rapid losses of carbon resulting from carbon management strategies could exacerbate the global warming rather than mitigating it. Such potential losses include rapid loss of carbon in vegetation due to fire and rapid loss of soil carbon triggered by reductions in ground cover (e.g., fire, drought). Therefore, strategies for terrestrial carbon sequestration must determine how to increase terrestrial carbon while minimizing the risk of large-scale catastrophic losses. Our objectives in this paper are to (1) highlight approaches that are being considered in terms of terrestrial carbon sequestration, (2) highlight case studies for which large losses of carbon may occur, and (3) suggest future directions and application for terrestrial carbon sequestration.

Breshears, D. D. (David D.); Ebinger, M. H. (Michael H.); Unkefer, P. J. (Pat J.)

2001-01-01

21

Very large common fragile site genes and their potential role in cancer development.  

PubMed

Common fragile sites (CFSs) are large chromosomal regions that are hot-spots for alterations especially within cancer cells. The three most frequently expressed CFS regions (FRA3B, FRA16D and FRA6E) contain genes that span extremely large genomic regions (FHIT, WWOX and PARK2, respectively), and these genes were found to function as important tumor suppressors. Many other CFS regions contain extremely large genes that are also targets of alterations in multiple cancers, but none have yet been demonstrated to function as tumor suppressors. The loss of expression of just FHIT or WWOX has been found to be associated with a worse overall clinical outcome. Studies in different cancers have revealed that some cancers have decreased expression of multiple large CFS genes. This loss of expression could have a profound phenotypic effect on these cells. In this review, we will summarize the known large common fragile site genes and discuss their potential relationship to cancer development. PMID:25300511

Gao, Ge; Smith, David I

2014-12-01

22

Betavoltaics using scandium tritide and contact potential difference  

Microsoft Academic Search

Tritium-powered betavoltaic micropower sources using contact potential difference (CPD) are demonstrated. Thermally stable scandium tritide thin films with a surface activity of 15 mCi?cm2 were used as the beta particle source. The electrical field created by the work function difference between the ScT film and a platinum or copper electrode was used to separate the beta-generated electrical charge carriers. Open

Baojun Liu; Kevin P. Chen; Nazir P. Kherani; Stefan Zukotynski; Armando B. Antoniazzi

2008-01-01

23

Betavoltaics using scandium tritide and contact potential difference  

Microsoft Academic Search

Tritium-powered betavoltaic micropower sources using contact potential difference (CPD) are demonstrated. Thermally stable scandium tritide thin films with a surface activity of 15 mCi\\/cm2 were used as the beta particle source. The electrical field created by the work function difference between the ScT film and a platinum or copper electrode was used to separate the beta-generated electrical charge carriers. Open

Baojun Liu; Kevin P. Chen; Nazir P. Kherani; Stefan Zukotynski; Armando B. Antoniazzi

2008-01-01

24

Energetic recoils in UO2 simulated using five different potentials  

NASA Astrophysics Data System (ADS)

This report presents the results of classical molecular dynamics simulations of the diffuse premelting transition, melting, and defect production by 1 keV U recoils in UO2 using five different rigid ion potentials. The experimentally observed premelting transition occurred for all five cases. For all the potentials studied, dynamic defect annealing is highly effective and is accompanied by replacement events on the anion sublattice. The primary damage state after ˜15 ps consists of isolated Frenkel pairs and interstitial and vacancy clusters of various sizes. The average displacement energy varies from ˜28 to ˜83 eV and the number of Frenkel pairs is different by a factor of 3 depending on the choice of potential. The size and spatial distribution of vacancy and interstitial clusters is drastically different for the potentials studied. The results provide statistics of defect production. They point to a pressing need to determine defect formation, migration, and binding energies in UO2 from first principles and to develop reliable potentials based on this data for simulating microstructural evolution in nuclear fuel under operating conditions.

Devanathan, Ram; Yu, Jianguo; Weber, William J.

2009-05-01

25

Energetic recoils in UO2 simulated using five different potentials.  

PubMed

This report presents the results of classical molecular dynamics simulations of the diffuse premelting transition, melting, and defect production by 1 keV U recoils in UO(2) using five different rigid ion potentials. The experimentally observed premelting transition occurred for all five cases. For all the potentials studied, dynamic defect annealing is highly effective and is accompanied by replacement events on the anion sublattice. The primary damage state after approximately 15 ps consists of isolated Frenkel pairs and interstitial and vacancy clusters of various sizes. The average displacement energy varies from approximately 28 to approximately 83 eV and the number of Frenkel pairs is different by a factor of 3 depending on the choice of potential. The size and spatial distribution of vacancy and interstitial clusters is drastically different for the potentials studied. The results provide statistics of defect production. They point to a pressing need to determine defect formation, migration, and binding energies in UO(2) from first principles and to develop reliable potentials based on this data for simulating microstructural evolution in nuclear fuel under operating conditions. PMID:19425785

Devanathan, Ram; Yu, Jianguo; Weber, William J

2009-05-01

26

Abnormalities of nasal potential difference measurement in Liddle's syndrome.  

PubMed Central

In Liddle's syndrome, a rare inherited form of hypertension, epithelial sodium channel mutations appear to cause high blood pressure by increasing sodium reabsorption through sodium channels in the renal distal tubule. This increase in channel activity has not been confirmed previously by in vivo measurement. We have made transnasal potential difference measurements (effective in detection of increased sodium channel activity in cystic fibrosis) in three brothers with genetically proven Liddle's syndrome, their unaffected sister, and 40 normotensive controls. Maximum potential difference after 2 wk off treatment in the affected brothers was -30.4+/-1.2 mV (values mean+/-SD, lumen-negative with respect to submucosa) and was significantly more lumen-negative than that of the control group (-18.6+/-6.8 mV, P = 0.0228) or the unaffected sister (-18.25 mV, P < 0.01). The change in potential difference after topical application of 10(-)4 M amiloride was greater in the Liddle's patients, 14.0+/-2.1 mV, than in controls (7.9+/-3.9 mV, P = 0.0126) or the unaffected sister (5.5 mV, P < 0.05). This is the first in vivo demonstration of increased sodium channel activity in Liddle's syndrome. If these results are confirmed in other kindreds with this condition, then nasal potential difference measurements could provide a simple clinical test for Liddle's syndrome. PMID:9649551

Baker, E; Jeunemaitre, X; Portal, A J; Grimbert, P; Markandu, N; Persu, A; Corvol, P; MacGregor, G

1998-01-01

27

Doubling potential of fibroblasts from different species after ionising radiation  

Microsoft Academic Search

IT is well known that chicken fibroblasts invariably die after a certain number of doublings in vitro (cell senescence) and that they have never been established by any chemical or physical agent1. On the other hand, mouse fibroblasts invariably acquire spontaneously an infinite growth potential, and transformation can be induced at a high frequency by different oncogenes2. Other species like

A. Macieira-Coelho; C. Diatloff; E. MALAISE

1976-01-01

28

Correlation of variations in intraluminal pressure and potential differences in the perfused colen.  

PubMed Central

To investigate the nature of variations in the large intestine potential differences, a continuous perfusion of isotonic saline was carried out in the colon of 14 rats. Intraluminal pressure and potential differences between the lumen and the peritoneal cavity were continuously and simultaneously recorded, while impedance of the system and respiration were also constantly monitored. To obtain a quantitative evaluation of the data, Fast Fouier Transform was performed on the signals and their derivatives which were auto- and cross-correlated. While there was no obvious relation between pressure and potential in the unperfused colon, there was clear visual qualirative evidence that, during steady state conditions of perfusion, an increase in intraluminal pressure was accompanied by a decrease in potential differences, while impedance of the recording system remained unchanged. Computer analysis disclosed four narrow ranges of stable frequencies for both pressure and potential. They were centred around 0-3, 1-75, 10-7, and 75 cycles per minute, the latter being synchronous with respiration. It is concluded that the variations of potential differences recorded during perfusion, a well-know phenomenon, are not electrical artefacts: the fast rhythm is probably induced by respiration, which increases intracolonic pressure and that, in turn, reduces the absolute value of potential differences, which remain negative mucosa versus serosa. The slower rhythms are synchronous for pressure and potential. Mechanisms responsible for the decrease in potential related to the increase in pressure remain unknown. PMID:590835

Postaire, J G; Gerard, J; Devroede, G; Van Houtte, N

1977-01-01

29

Acylglycerol structure of peanut oils of different atherogenic potential  

Microsoft Academic Search

Detailed investigation was made of the triacylglycerol structure of native, simulated, and interesterified peanut oils, which\\u000a had previously been shown to differ markedly in their atherogenic potential. By means of chromatographic and stereospecific\\u000a analyses, it was shown that the more atherogenic native oil contains a significantly greater proportion of triacylglycerols\\u000a with linoleic insn-2-position and arachidic, behenic, and lignoceric acids insn-3-position

J. J. Myher; L. Marai; A. Kuksis; D. Kritchevsky

1977-01-01

30

Germination Responses to Water Potential in Neotropical Pioneers Suggest Large-seeded Species Take More Risks  

PubMed Central

Background and Aims In neotropical forests, very small-seeded pioneer species (<0·1 mg seed mass) recruit preferentially in small tree fall gaps and at gap edges, but large-seeded pioneers do not. Since water availability is related to gap size, these differences in microsite preference may reflect in part species-specific differences in germination at reduced water potentials. Methods For 14 neotropical pioneer species, the hypothesis is tested that small-seeded species, with shallow initial rooting depths, reduce the risks associated with desiccation by germinating more slowly and at higher water potentials than large-seeded species. Key Results Germination occurred both more quickly and at lower water potentials with increasing seed mass. For example, Ochroma pyramidale (seed mass 5·5 mg) had a time to 50 % germination (T50) of 2·8 d and a median base potential for germination (?b50) of ?1·8 MPa while Clidemia quinquenervia (seed mass 0·017 mg) had a T50 of 17·6 d and ?b50 of ?1·1 MPa. Conclusions These data suggest that small-seeded species germinate only in comparatively moist microsites, such as small canopy gaps, which may reduce the risk of drought-induced mortality. Conversely, large-seeded species are able to germinate in the drier environment of large gaps, where they benefit by enhanced seedling growth in a high irradiance environment. The positive association of seed size and canopy gap size for optimal seedling establishment is maintained by differential germination responses to soil water availability coupled with the scaling of radicle growth rate and seed size, which collectively confer greater drought tolerance on large-seeded species. PMID:18840874

Daws, Matthew I.; Crabtree, Lora M.; Dalling, James W.; Mullins, Christopher E.; Burslem, David F. R. P.

2008-01-01

31

Approximate registration of point clouds with large scale differences  

NASA Astrophysics Data System (ADS)

3D reconstruction of objects is a basic task in many fields, including surveying, engineering, entertainment and cultural heritage. The task is nowadays often accomplished with a laser scanner, which produces dense point clouds, but lacks accurate colour information, and lacks per-point accuracy measures. An obvious solution is to combine laser scanning with photogrammetric recording. In that context, the problem arises to register the two datasets, which feature large scale, translation and rotation differences. The absence of approximate registration parameters (3D translation, 3D rotation and scale) precludes the use of fine-registration methods such as ICP. Here, we present a method to register realistic photogrammetric and laser point clouds in a fully automated fashion. The proposed method decomposes the registration into a sequence of simpler steps: first, two rotation angles are determined by finding dominant surface normal directions, then the remaining parameters are found with RANSAC followed by ICP and scale refinement. These two steps are carried out at low resolution, before computing a precise final registration at higher resolution.

Novak, D.; Schindler, K.

2013-10-01

32

Comparing different coarse-grained potentials for star polymers  

NASA Astrophysics Data System (ADS)

We compare different coarse-grained single-blob models for star polymers. We find that phenomenological models inspired by the Daoud-Cotton theory reproduce quite poorly the thermodynamics of these systems, even if the potential is assumed to be density dependent, as done in the analysis of experimental results. Using the numerically determined coarse-grained potential, we also determine the minimum value fc of the functionality of the star polymer for which a fluid-solid transition occurs. By applying the Hansen-Verlet criterion we find 35 < fc ? 40. This result is confirmed by an analysis that uses the modified (reference) hypernetted chain method and is qualitatively consistent with previous work.

Menichetti, Roberto; Pelissetto, Andrea

2013-03-01

33

Sex-related differences in QTc effects potential of drugs.  

PubMed

The objective of this study was to examine the drug-induced sex differences in corrected QT (QTc) interval by re-analyzing the data collected in thorough QT studies submitted to the US Food and Drug Administration (FDA). We examined 64 studies available in the FDA database by performing a time-matched, baseline adjusted ANCOVA on the QTc response stratified by sex. We used several summaries to capture the differences between males and females in drug response QTc effects. They included sample means, upper confidence intervals, and areas under the curves. At baseline, females tend to have a higher QTc response than males. After treatment, various summaries suggest that females tend to have a higher QTc effect than males. However, the magnitude of the difference is small and is often not statistically significant. Several limitations can be raised about these available data: 1) available QT studies were not designed to examine the sex differences in QTc effects, 2) the findings were undermined by large variations seen in QT data, and 3) our summary statistics are descriptive in nature and are not for inferential purposes. Nonetheless, the results suggest that females tend to have a higher QTc effect than males, although the difference tends to be small. Further research is needed to formally address the question. PMID:21682673

Dinh, Phillip; Sun, Jin; Bai, Steve; Kordzakhia, George

2011-09-01

34

Foetal and adult cardiomyocyte progenitor cells have different developmental potential  

PubMed Central

Abstract In the past years, cardiovascular progenitor cells have been isolated from the human heart and characterized. Up to date, no studies have been reported in which the developmental potential of foetal and adult cardiovascular progenitors was tested simultaneously. However, intrinsic differences will likely affect interpretations regarding progenitor cell potential and application for regenerative medicine. Here we report a direct comparison between human foetal and adult heart-derived cardiomyocyte progenitor cells (CMPCs). We show that foetal and adult CMPCs have distinct preferences to differentiate into mesodermal lineages. Under pro-angiogenic conditions, foetal CMPCs form more endothelial but less smooth muscle cells than adult CMPCs. Foetal CMPCs can also develop towards adipocytes, whereas neither foetal nor adult CMPCs show significant osteogenic differentiation. Interestingly, although both cell types differentiate into heart muscle cells, adult CMPCs give rise to electrophysiologically more mature cardiomyocytes than foetal CMPCs. Taken together, foetal CMPCs are suitable for molecular cell biology and developmental studies. The potential of adult CMPCs to form mature cardiomyocytes and smooth muscle cells may be essential for cardiac repair after transplantation into the injured heart. PMID:20219011

Van Vliet, Patrick; Smits, Anke M; De Boer, Teun P; Korfage, Tom H; Metz, Corina HG; Roccio, Marta; Van Der Heyden, Marcel AG; Van Veen, Toon AB; Sluijter, Joost PG; Doevendans, Pieter A; Goumans, Marie-José

2010-01-01

35

Saturation of transpolar potential for large Y component interplanetary magnetic field  

Microsoft Academic Search

This study examines the response of the transpolar potential to a large Y component interplanetary magnetic field (IMF By). The transpolar potential responds nonlinearly and saturates for large IMF By in the Lyon-Fedder-Mobarry (LFM) global MHD simulation, just as it does for large southward IMF (?Bz). Data from Defense Meteorological Satellite Program (DMSP) satellites and Assimilative Mapping of Ionospheric Electrodynamics

E. J. Mitchell; R. E. Lopez; R. J. Bruntz; M. Wiltberger; J. G. Lyon; R. C. Allen; S. J. Cockrell; P. L. Whittlesey

2010-01-01

36

Nasal Potential Difference in Cystic Fibrosis considering Severe CFTR Mutations  

PubMed Central

The gold standard for diagnosing cystic fibrosis (CF) is a sweat chloride value above 60?mEq/L. However, this historical and important tool has limitations; other techniques should be studied, including the nasal potential difference (NPD) test. CFTR gene sequencing can identify CFTR mutations, but this method is time-consuming and too expensive to be used in all CF centers. The present study compared CF patients with two classes I-III CFTR mutations (10 patients) (G1), CF patients with classes IV-VI CFTR mutations (five patients) (G2), and 21 healthy subjects (G3). The CF patients and healthy subjects also underwent the NPD test. A statistical analysis was performed using the Mann-Whitney, Kruskal-Wallis, ?2, and Fisher's exact tests, ? = 0.05. No differences were observed between the CF patients and healthy controls for the PDMax, ?amiloride, and ?chloride + free + amiloride markers from the NPD test. For the finger value, a difference between G2 and G3 was described. The Wilschanski index values were different between G1 and G3. In conclusion, our data showed that NPD is useful for CF diagnosis when classes I-III CFTR mutations are screened. However, if classes IV-VI are considered, the NPD test showed an overlap in values with healthy subjects. PMID:25667564

Ng, Ronny Tah Yen; Marson, Fernando Augusto de Lima; Ribeiro, Jose Dirceu; Ribeiro, Antonio Fernando; Bertuzzo, Carmen Silvia; Ribeiro, Maria Angela Gonçalves de Oliveira; Severino, Silvana Dalge; Sakano, Eulalia

2015-01-01

37

Nasal Potential Difference in Cystic Fibrosis considering Severe CFTR Mutations.  

PubMed

The gold standard for diagnosing cystic fibrosis (CF) is a sweat chloride value above 60?mEq/L. However, this historical and important tool has limitations; other techniques should be studied, including the nasal potential difference (NPD) test. CFTR gene sequencing can identify CFTR mutations, but this method is time-consuming and too expensive to be used in all CF centers. The present study compared CF patients with two classes I-III CFTR mutations (10 patients) (G1), CF patients with classes IV-VI CFTR mutations (five patients) (G2), and 21 healthy subjects (G3). The CF patients and healthy subjects also underwent the NPD test. A statistical analysis was performed using the Mann-Whitney, Kruskal-Wallis, ? (2), and Fisher's exact tests, ? = 0.05. No differences were observed between the CF patients and healthy controls for the PDMax, ?amiloride, and ?chloride + free + amiloride markers from the NPD test. For the finger value, a difference between G2 and G3 was described. The Wilschanski index values were different between G1 and G3. In conclusion, our data showed that NPD is useful for CF diagnosis when classes I-III CFTR mutations are screened. However, if classes IV-VI are considered, the NPD test showed an overlap in values with healthy subjects. PMID:25667564

Ng, Ronny Tah Yen; Marson, Fernando Augusto de Lima; Ribeiro, Jose Dirceu; Ribeiro, Antonio Fernando; Bertuzzo, Carmen Silvia; Ribeiro, Maria Angela Gonçalves de Oliveira; Severino, Silvana Dalge; Sakano, Eulalia

2015-01-01

38

One Week Before the Election, Nader's Potential Impact Looms Large  

NSDL National Science Digital Library

Over the weekend, Democratic Vice-Presidential candidate Joe Lieberman urged Nader-supporters to consider that a vote for Nader could well end up giving George W. Bush the White House. Lieberman was echoing the thoughts of a growing number of liberals, including Gloria Steinem and the presidents of the Sierra Club and the National Organization for Women, who are stumping for Gore in selected toss-up states. Such concerns are justified by recent polling data that give Nader sufficient support in states like Washington, Oregon, Wisconsin, Minnesota, and Michigan to tip the balance from Gore to Bush, assuming, as most polls show, that Nader draws more from potential Gore voters than potential Bush voters. In this same vein, some earlier prominent, Nader-led activists, dubbed "Nader's Raiders," have shifted their loyalties and, at the prospect of a Bush presidency, turned to Gore. But the Green Party's candidate is himself undeterred, stating frankly on ABC News's This Week Sunday that "if he [Gore] cannot defeat the bumbling Texas governor with that horrific record, what good is he? It should be a slam dunk." Analysts are divided over whether would-be Nader voters will break at the last minute for Gore, accepting the thinking of democratic leaders that only a vote for a potential winner means anything, or whether they will stick with Nader, using their vote, it would seem, to express a fundamental dissatisfaction with the current political system.

Charbonneau, David D.

39

Floating potential of large dust grains with electron emission  

SciTech Connect

Electron emission from the surface of solid particles plays an important role in many dusty plasma phenomena and applications. Examples of such cases include fusion plasmas and dusty plasma systems in our solar system. Electron emission complicates the physics of the plasma-dust interaction. One of the most important aspects of the physics of the dust plasma interaction is the calculation of the particle's floating potential. This is the potential a dust particle acquires when it is in contact with a plasma and it plays a very important role for determining its dynamical behaviour. The orbital motion limited (OML) approach is used in most cases in the literature to model the dust charging physics. However, this approach has severe limitations when the size of the particles is larger than the electron Debye length ?{sub De}. Addressing this shortcoming for cases without electron emission, a modified version of OML (MOML) was developed for modelling the charging physics of dust grains larger than the electron Debye length. In this work, we will focus on extending MOML in cases where the particles emit electrons. Furthermore, a general method for calculating the floating potential of dust particles with electron emission will be presented for a range of grain sizes.

Bacharis, M., E-mail: minas.bacharis03@imperial.ac.uk [Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BW (United Kingdom)

2014-07-15

40

Meson Mass at Large Baryon Chemical Potential in Dense QCD  

E-print Network

We reexamine the quark mass induced term in chiral Lagrangian in color-flavor locking phase in dense QCD, and show that the meson mass term is determined by three independent invariants under chiral-axial symmetry, and a meson mass is given in terms of the quark mass, gap, and the chemical potential by $m_{\\pi}^2\\sim m_q^2\\Delta\\bar{\\Delta}/\\mu^2\\ln(\\mu^2/\\Delta^2)$. Thus mesons become massless as $\\mu\\to\\infty$.

Deog Ki Hong; Taekoon Lee; Dong-Pil Min

2000-02-21

41

Pushbroom radiometry and its potential using large space antennas  

NASA Technical Reports Server (NTRS)

Electromagnetic radiation is emitted by matter which was heated to a temperature above absolute zero. The amount of blackbody radiation in the microwave frequency region of interest (10 to the 8th power f 10 to the 10th power Hz) emitted by matter can be determined from the Rayleigh-Jeans approximation to Planck's Radiation Law. The amount of electromagnetic radiation from matter which is not a blackbody is a function of the emissivity of the material. The emissivity is a factor less than unity and is a function of several parameters including chemical composition, temperature, frequency, surface characteristics, and viewing angle. A radiometer is an instrument which detects and provides a measure of the electromagnetic radiation being emitted by a material or surface area within the radiometer's antenna beamwidth. Microwave radiometers provide the capability for remote measurements from Earth orbits of geophysical parameters. These measurements will require the use of a microwave imaging radiometer using a large aperture deployable antenna with multiple beams in a pushbroom mode to achieve high spatial resolution and large swath width.

Harrington, R. F.; Keafer, L. S., Jr.

1983-01-01

42

Resonance measurement of periodically driven contact potential difference  

E-print Network

A new type of quartz resonance device for measurements of oscillations of the contact potential difference induced by modulated light is described. Special attention is devoted to the compensation of the constructive capacitance of the quartz resonator by a negative capacitance. In such a way the the quartz resonance filter is very narrow and at the same time has extremely small total bandwidth, which improves significantly the signal to noise ratio. For metals, this device gives the temperature dependence of the work function and opens perspectives for creation of imaging spectroscopy based on this temperature derivative. The proposed device can be used for creation of defectoscopy of metallic materials based on the temperature derivative of the work function.

Yordanov, Vasil G

2015-01-01

43

Obtaining Potential Field Solution with Spherical Harmonics and Finite Differences  

E-print Network

Potential magnetic field solutions can be obtained based on the synoptic magnetograms of the Sun. Traditionally, a spherical harmonics decomposition of the magnetogram is used to construct the current and divergence free magnetic field solution. This method works reasonably well when the order of spherical harmonics is limited to be small relative to the resolution of the magnetogram, although some artifacts, such as ringing, can arise around sharp features. When the number of spherical harmonics is increased, however, using the raw magnetogram data given on a grid that is uniform in the sine of the latitude coordinate can result in inaccurate and unreliable results, especially in the polar regions close to the Sun. We discuss here two approaches that can mitigate or completely avoid these problems: i) Remeshing the magnetogram onto a grid with uniform resolution in latitude, and limiting the highest order of the spherical harmonics to the anti-alias limit; ii) Using an iterative finite difference algorithm t...

Toth, Gabor; Huang, Zhenguang; 10.1088/0004-637X/732/2/102

2011-01-01

44

High sensitivity comparison of potential differences between two Josephson junctions  

SciTech Connect

The experimental and theoretical exactness of the Josephson voltage-frequency relation dUPSILON/dt = (2e/h)V and its relation to the accuracy of quantum electrodynamics, as well as the possible discrepancy between them are discussed. The experiment was designed to compare the electrochemical potential difference between two Josephson junctions by putting them in a DC SQUID configuration, and biasing them on a microwave induced constant-voltage step. On a step, the voltage across the junctions is determined by the applied microwave frequency v through the Josephson relation V = (h/2e) vn, where n is the order of the step. Faraday's law implies that any potential difference ..delta..V around the closed loop has to be sustained by a changing magnetic flux inside the closed loop. Thus under this condition: ((h/2e)/sub 1/ - (h/2e)/sub 2/)vn = dUPSILON/dt, so that any local dependence of the Josephson relation can be measured by monitoring the flux in the DC SQUID. The flux in the DC SQUID was measured by an RF SQUID, coupled to the DC SQUID by a superconducting flux transformer. The use of the RF SQUID and high voltage steps results in very high sensitivity of the measurement. The relative exactness of the Josephson relation between two similar junctions is established to less than one part in 10/sup 17/. This is almost one billion times better than previous results. Measurements were also made on two dissimilar junctions, namely an In microbridge and a Nb-Cu-Nb junction. For those junctions, the relative exactness is established to about two parts in 10/sup 16/. The reduced accuracy is mainly attributed to the lower biasing voltage used. The material and microscopic coupling mechanism dependence of the Josephson relation was shown to be nonexistent at this accuracy.

Tsai, J.S.

1983-01-01

45

Potential for large outbreaks of Ebola virus disease.  

PubMed

Outbreaks of Ebola virus can cause substantial morbidity and mortality in affected regions. The largest outbreak of Ebola to date is currently underway in West Africa, with 3944 cases reported as of 5th September 2014. To develop a better understanding of Ebola transmission dynamics, we revisited data from the first known Ebola outbreak, which occurred in 1976 in Zaire (now Democratic Republic of Congo). By fitting a mathematical model to time series stratified by disease onset, outcome and source of infection, we were able to estimate several epidemiological quantities that have previously proved challenging to measure, including the contribution of hospital and community infection to transmission. We found evidence that transmission decreased considerably before the closure of the hospital, suggesting that the decline of the outbreak was most likely the result of changes in host behaviour. Our analysis suggests that the person-to-person reproduction number was 1.34 (95% CI: 0.92-2.11) in the early part of the outbreak. Using stochastic simulations we demonstrate that the same epidemiological conditions that were present in 1976 could have generated a large outbreak purely by chance. At the same time, the relatively high person-to-person basic reproduction number suggests that Ebola would have been difficult to control through hospital-based infection control measures alone. PMID:25480136

Camacho, A; Kucharski, A J; Funk, S; Breman, J; Piot, P; Edmunds, W J

2014-12-01

46

Potential for large outbreaks of Ebola virus disease  

PubMed Central

Outbreaks of Ebola virus can cause substantial morbidity and mortality in affected regions. The largest outbreak of Ebola to date is currently underway in West Africa, with 3944 cases reported as of 5th September 2014. To develop a better understanding of Ebola transmission dynamics, we revisited data from the first known Ebola outbreak, which occurred in 1976 in Zaire (now Democratic Republic of Congo). By fitting a mathematical model to time series stratified by disease onset, outcome and source of infection, we were able to estimate several epidemiological quantities that have previously proved challenging to measure, including the contribution of hospital and community infection to transmission. We found evidence that transmission decreased considerably before the closure of the hospital, suggesting that the decline of the outbreak was most likely the result of changes in host behaviour. Our analysis suggests that the person-to-person reproduction number was 1.34 (95% CI: 0.92–2.11) in the early part of the outbreak. Using stochastic simulations we demonstrate that the same epidemiological conditions that were present in 1976 could have generated a large outbreak purely by chance. At the same time, the relatively high person-to-person basic reproduction number suggests that Ebola would have been difficult to control through hospital-based infection control measures alone. PMID:25480136

Camacho, A.; Kucharski, A.J.; Funk, S.; Breman, J.; Piot, P.; Edmunds, W.J.

2014-01-01

47

Scaling differences between large interplate and intraplate earthquakes  

NASA Technical Reports Server (NTRS)

A study of large intraplate earthquakes with well determined source parameters shows that these earthquakes obey a scaling law similar to large interplate earthquakes, in which M sub o varies as L sup 2 or u = alpha L where L is rupture length and u is slip. In contrast to interplate earthquakes, for which alpha approximately equals 1 x .00001, for the intraplate events alpha approximately equals 6 x .0001, which implies that these earthquakes have stress-drops about 6 times higher than interplate events. This result is independent of focal mechanism type. This implies that intraplate faults have a higher frictional strength than plate boundaries, and hence, that faults are velocity or slip weakening in their behavior. This factor may be important in producing the concentrated deformation that creates and maintains plate boundaries.

Scholz, C. H.; Aviles, C. A.; Wesnousky, S. G.

1985-01-01

48

Research on large color difference evaluation using printed samples  

Microsoft Academic Search

A grey-scale psychophysical experiment was carried out for evaluating color differences using printed color patches. In total, 100 pairs of printed samples were prepared with an average ?E*ab of 13.8 units. Each pair was assessed 60 times by a panel of 20 normal color vision observers. The visual results were used to test the existing color-difference formulae. The results showed

Min Huang; Haoxue Liu; Guihua Cui; M. Ronnier Luo

2011-01-01

49

Different patterns of electrical activity lead to long-term potentiation by activating different intracellular pathways.  

PubMed

Deciphering and storing information coded in different firing patterns are important properties of neuronal networks, as they allow organisms to respond and adapt to external and internal events. Here we report that hippocampal CA1 pyramidal neurons respond to brief bursts of high-frequency stimulation (HFS) and ? burst stimulation (TBS) with long-lasting enhanced responses (long-term potentiation [LTP]), albeit by engaging different signaling pathways. TBS induces LTP through calpain-1-mediated suprachiasmatic nucleus circadian oscillatory protein degradation, ERK activation, and actin polymerization, whereas HFS requires adenosine A2 receptors, PKA, and actin polymerization. TBS- but not HFS-induced LTP is impaired in calpain-1 knock-out mice. However, TBS-induced LTP and learning impairment in knock-out mice are restored by activating the HFS pathway. Thus, different patterns of rhythmic activities trigger potentiation by activating different pathways, and cross talks between these can be used to restore LTP and learning when elements of the pathways are impaired. PMID:25589756

Zhu, Guoqi; Liu, Yan; Wang, Yubin; Bi, Xiaoning; Baudry, Michel

2015-01-14

50

Study of cascades damage in Ni by MD with different interatomic potentials  

NASA Astrophysics Data System (ADS)

Molecular dynamics (MD) simulations, performed with embedded atom potentials, are used to understand the formation of defects following displacement cascades in Ni. Different empirical potentials, presenting large differences in stacking fault energy (SFE), are used. Simulations were conducted with primary knock-on (PKA) atom energies of 5-40 keV at a temperature of 10 K. Defects include, depending on the potential, individual point defects (vacancies and interstitials), dislocation loops and stacking fault tetrahedra (SFT). The results are related to TEM observations, and the mismatch between these two pictures is discussed. It appears that in a collision cascade, the formation of an SFT does not depend only on the SFE but also on other parameters such as the mobility of vacancies and self-interstitials, or the presence of replacement collision sequences. Based on these calculations we suggest that the formation of clusters of vacancies is a prerequisite to the formation of SFTs.

Yao, Z.; Caturla, M. J.; Schäublin, R.

2007-08-01

51

Achievement Differences between Large and Small Schools in Texas  

ERIC Educational Resources Information Center

The purpose of this study was to determine whether there exists a relationship between student achievement in Texas, as measured by the Texas Assessment of Knowledge and Skills (TAKS) test, and the size of the high school at different socioeconomic levels. This study compared five size categories of Texas high schools to determine which size high…

Stewart, Lee

2009-01-01

52

GENDER DIFFERENCES IN ORGANIZATIONAL LEADERSHIP A Large Sample Study  

Microsoft Academic Search

In order to investigate possible gender differences in organizational leadership behavior, a diverse sample of North American male and female managers (n=1,800) matched for organization, management level, job function, and management experience were com- pared on 22 leadership behaviors and 3 effectiveness measures. Outcome measures were assessed using a 360-degree strategy in which each manager was evaluated by self, boss,

Robert I. Kabacoff

2010-01-01

53

Artificial Boundary Conditions Based on the Difference Potentials Method  

NASA Technical Reports Server (NTRS)

While numerically solving a problem initially formulated on an unbounded domain, one typically truncates this domain, which necessitates setting the artificial boundary conditions (ABC's) at the newly formed external boundary. The issue of setting the ABC's appears to be most significant in many areas of scientific computing, for example, in problems originating from acoustics, electrodynamics, solid mechanics, and fluid dynamics. In particular, in computational fluid dynamics (where external problems present a wide class of practically important formulations) the proper treatment of external boundaries may have a profound impact on the overall quality and performance of numerical algorithms. Most of the currently used techniques for setting the ABC's can basically be classified into two groups. The methods from the first group (global ABC's) usually provide high accuracy and robustness of the numerical procedure but often appear to be fairly cumbersome and (computationally) expensive. The methods from the second group (local ABC's) are, as a rule, algorithmically simple, numerically cheap, and geometrically universal; however, they usually lack accuracy of computations. In this paper we first present a survey and provide a comparative assessment of different existing methods for constructing the ABC's. Then, we describe a relatively new ABC's technique of ours and review the corresponding results. This new technique, in our opinion, is currently one of the most promising in the field. It enables one to construct such ABC's that combine the advantages relevant to the two aforementioned classes of existing methods. Our approach is based on application of the difference potentials method attributable to V. S. Ryaben'kii. This approach allows us to obtain highly accurate ABC's in the form of certain (nonlocal) boundary operator equations. The operators involved are analogous to the pseudodifferential boundary projections first introduced by A. P. Calderon and then also studied by R. T. Seeley. The apparatus of the boundary pseudodifferential equations, which has formerly been used mostly in the qualitative theory of integral equations and PDE'S, is now effectively employed for developing numerical methods in the different fields of scientific computing.

Tsynkov, Semyon V.

1996-01-01

54

Kinematic Morphology of Large-scale Structure: Evolution from Potential to Rotational Flow  

NASA Astrophysics Data System (ADS)

As an alternative way to describe the cosmological velocity field, we discuss the evolution of rotational invariants constructed from the velocity gradient tensor. Compared with the traditional divergence-vorticity decomposition, these invariants, defined as coefficients of the characteristic equation of the velocity gradient tensor, enable a complete classification of all possible flow patterns in the dark-matter comoving frame, including both potential and vortical flows. We show that this tool, first introduced in turbulence two decades ago, is very useful for understanding the evolution of the cosmic web structure, and in classifying its morphology. Before shell crossing, different categories of potential flow are highly associated with the cosmic web structure because of the coherent evolution of density and velocity. This correspondence is even preserved at some level when vorticity is generated after shell crossing. The evolution from the potential to vortical flow can be traced continuously by these invariants. With the help of this tool, we show that the vorticity is generated in a particular way that is highly correlated with the large-scale structure. This includes a distinct spatial distribution and different types of alignment between the cosmic web and vorticity direction for various vortical flows. Incorporating shell crossing into closed dynamical systems is highly non-trivial, but we propose a possible statistical explanation for some of the phenomena relating to the internal structure of the three-dimensional invariant space.

Wang, Xin; Szalay, Alex; Aragón-Calvo, Miguel A.; Neyrinck, Mark C.; Eyink, Gregory L.

2014-09-01

55

Kinematic Morphology of Large-scale Structure: Evolution from Potential to Rotational Flow  

NASA Astrophysics Data System (ADS)

As an alternative way of describing the cosmological velocity field, we discuss the evolution of rotational invariants constructed from the velocity gradient tensor. Compared with the traditional divergence-vorticity decomposition, these invariants, defined as coefficients of characteristic equation of the velocity gradient tensor, enable a complete classification of all possible flow patterns in the dark-matter comoving frame, including both potential and vortical flows. Before shell-crossing, different categories of potential flow are highly associated with cosmic web structure, because of the coherent evolution of density and velocity. This correspondence is even preserved at some level when vorticity is generated after shell-crossing. The evolution from the potential to vortical flow can be traced continuously by these invariants. With the help of this tool, we show that the vorticity is generated in a particular way that is highly correlated with the large-scale structure. This includes a distinct spatial distribution and different types of alignment between cosmic web and vorticity direction for various vortical flows. Incorporating shell-crossing into closed dynamical systems is highly non-trivial, but we propose a possible statistical explanation for some of these phenomena relating to the internal structure of the three-dimensional invariants space.

Wang, Xin; Szalay, A. S.; Aragon-Calvo, M. A.; Neyrinck, M. C.; Eyink, G. L.

2014-01-01

56

Injury Differences Between Small and Large Overlap Frontal Crashes  

PubMed Central

Because small overlap impacts have recently emerged as a crash mode posing great injury risk to occupants, a detailed analysis of US crash data was conducted using the NASS/CDS and CIREN databases. Frontal crashes were subcategorized into small overlap impact (SOI) and large overlap impact (LOI) using crash and crush characteristics from the datasets. Injuries to head, spine, chest, hip and pelvis, and lower extremities were parsed and compared between crash types. MAIS 3+ occupants in NASS/CDS and CIREN demonstrated increased incidence of head, chest, spine, and hip/pelvis injuries in SOI compared to LOI. In NASS/CDS, subgaleal hematoma represented 48.6% of SOI head injury codes but 27.6% in LOI. Cervical spine posterior element fractures also represented greater proportions of SOI spine injuries (e.g., facet fractures: 27.8 vs. 14.0%), and proximal femur fractures represented a greater proportion of hip/pelvis injuries (e.g., intertrochanteric fracture: 32.5 vs. 11.8%). Tarsal/metatarsal fractures were a lesser proportion of lower extremity injuries in SOI compared to LOI. Occupant contact points inducing these injuries were observed in CIREN cases in some instances without compartment intrusion. These injuries suggest the substantial role of occupant kinematics in SOI which may induce suboptimal occupant restraint interaction. PMID:22105392

Hallman, Jason J.; Yoganandan, Narayan; Pintar, Frank A.; Maiman, Dennis J.

2011-01-01

57

Injury differences between small and large overlap frontal crashes.  

PubMed

Because small overlap impacts have recently emerged as a crash mode posing great injury risk to occupants, a detailed analysis of US crash data was conducted using the NASS/CDS and CIREN databases. Frontal crashes were subcategorized into small overlap impact (SOI) and large overlap impact (LOI) using crash and crush characteristics from the datasets. Injuries to head, spine, chest, hip and pelvis, and lower extremities were parsed and compared between crash types. MAIS 3+ occupants in NASS/CDS and CIREN demonstrated increased incidence of head, chest, spine, and hip/pelvis injuries in SOI compared to LOI. In NASS/CDS, subgaleal hematoma represented 48.6% of SOI head injury codes but 27.6% in LOI. Cervical spine posterior element fractures also represented greater proportions of SOI spine injuries (e.g., facet fractures: 27.8 vs. 14.0%), and proximal femur fractures represented a greater proportion of hip/pelvis injuries (e.g., intertrochanteric fracture: 32.5 vs. 11.8%). Tarsal/metatarsal fractures were a lesser proportion of lower extremity injuries in SOI compared to LOI. Occupant contact points inducing these injuries were observed in CIREN cases in some instances without compartment intrusion. These injuries suggest the substantial role of occupant kinematics in SOI which may induce suboptimal occupant restraint interaction. PMID:22105392

Hallman, Jason J; Yoganandan, Narayan; Pintar, Frank A; Maiman, Dennis J

2011-01-01

58

Estimating Large-Customer Demand Response Market Potential:Integrating Price and Customer Behavior  

SciTech Connect

ABSTRACT=Demand response (DR) is increasingly recognized asan essential ingredient to well-functioning electricity markets. DRmarket potential studies can answer questions about the amount of DRavailable in a given area, from which market segments. Several recent DRmarket potential studies have been conducted, most adapting techniquesused to estimate energy-efficiency (EE) potential. In this scoping study,we: reviewed and categorized seven recent DR market potential studies;recommended a methodology for estimating DR market potential for large,non-residential utility customers that uses price elasticities to accountfor behavior and prices; compiled participation rates and elasticityvalues from six DR options offered to large customers in recent years,and demonstrated our recommended methodology with large customer marketpotential scenarios at an illustrative Northeastern utility. We recommendan elasticity approach for large-customer DR options that rely oncusto!

Goldman, Charles; Hopper, Nicole; Bharvirkar, Ranjit; Neenan,Bernie; Cappers, Peter

2007-06-01

59

Interrelationship between colonic muscularis mucosae activity and changes in transmucosal potential difference.  

PubMed

This in vitro study investigated the relationship between rabbit colonic muscularis mucosae motor activity and changes in transmucosal potential difference. Spontaneous muscle contractions and potential difference oscillations occurred independently and were not neurally driven. ACh and histamine directly stimulated the muscularis mucosae, but their mucosal effects were largely indirect, suggesting that muscularis mucosae contractions promote epithelial secretion. 1,1-Dimethyl-4-phenyl-piperazinium iodide and vasoactive intestinal polypeptide induced large potential difference changes but small muscularis mucosae contractions, demonstrating mucosal secretion without significant muscle activity. Lowered intraluminal pH directly stimulated the muscle, whereas a bile salt-lipid mixture evoked TTX- and atropine-sensitive increases in its contractile activity. Increased intraluminal pressure and hypertonic luminal perfusion did not elicit muscularis mucosae excitation. Thus under basal conditions muscle and mucosal activities are independent, but evoked muscularis mucosae contractions can stimulate epithelial secretion. In response to specific luminal stimuli, muscularis mucosae motor activity is increased via the activation of cholinergic nerves. These data suggest that muscularis mucosae and mucosal functions are physiologically linked and that their activities can be coordinated by multiple mechanisms. PMID:11447028

Percy, W H; Brunz, J T; Burgers, R E; Fromm, T H; Merkwan, C L; van Dis, J

2001-08-01

60

The potential of large studies for building genetic risk prediction models  

Cancer.gov

Posted on March 04, 2013 NCI scientists have developed a new paradigm to assess hereditary risk prediction in common diseases, such as prostate cancer.  Researchers assessed the potential of using very large, genome-wide association studies (GWAS) to

61

Segregation distortion causes large-scale differences between male and female genomes in hybrid ants  

PubMed Central

Hybridization in isolated populations can lead either to hybrid breakdown and extinction or in some cases to speciation. The basis of hybrid breakdown lies in genetic incompatibilities between diverged genomes. In social Hymenoptera, the consequences of hybridization can differ from those in other animals because of haplodiploidy and sociality. Selection pressures differ between sexes because males are haploid and females are diploid. Furthermore, sociality and group living may allow survival of hybrid genotypes. We show that hybridization in Formica ants has resulted in a stable situation in which the males form two highly divergent gene pools whereas all the females are hybrids. This causes an exceptional situation with large-scale differences between male and female genomes. The genotype differences indicate strong transmission ratio distortion depending on offspring sex, whereby the mother transmits some alleles exclusively to her daughters and other alleles exclusively to her sons. The genetic differences between the sexes and the apparent lack of multilocus hybrid genotypes in males can be explained by recessive incompatibilities which cause the elimination of hybrid males because of their haploid genome. Alternatively, differentiation between sexes could be created by prezygotic segregation into male-forming and female-forming gametes in diploid females. Differentiation between sexes is stable and maintained throughout generations. The present study shows a unique outcome of hybridization and demonstrates that hybridization has the potential of generating evolutionary novelties in animals. PMID:20368452

Kulmuni, Jonna; Seifert, Bernhard; Pamilo, Pekka

2010-01-01

62

The radiative forcing potential of different climate geoengineering options  

Microsoft Academic Search

Climate geoengineering proposals seek to rectify the Earth's current and potential future radiative imbalance, either by reducing the absorption of incoming solar (shortwave) radiation, or by removing CO2 from the atmosphere and transferring it to long-lived reservoirs, thus increasing outgoing longwave radiation. A fundamental criterion for evaluating geoengineering options is their climate cooling effectiveness, which we quantify here in terms

T. M. Lenton; N. E. Vaughan

2009-01-01

63

The radiative forcing potential of different climate geoengineering options  

Microsoft Academic Search

Climate geoengineering proposals seek to rectify the Earth's current and potential future radiative imbalance, either by reducing the absorption of incoming solar (short- wave) radiation, or by removing CO2 from the atmosphere and transferring it to long-lived reservoirs, thus increasing outgoing longwave radiation. A fundamental criterion for evaluating geoengineering options is their climate cooling effectiveness, which we quantify here in

T. M. Lenton; N. E. Vaughan

2009-01-01

64

Evaluation of Curvularia intermedia ( Cochliobolus intermedius) as a potential microbial herbicide for large crabgrass ( Digitaria sanguinalis)  

Microsoft Academic Search

Curvularia intermedia, anamorph of the fungus Cochliobolus intermedius, was isolated from diseased crabgrass (Digitaria sp.) plants and evaluated in greenhouse studies for its potential as a microbial herbicide for control of large crabgrass (Digitaria sanguinalis). The objectives were to evaluate the host range of the fungus and to determine mortality and dry-weight reductions of large crabgrass as influenced by concentrations

A Michael Tilley; H Lynn Walker

2002-01-01

65

Large-rock avalanche deposits, eastern Basin and Range, Utah: Emplacement, diagenesis, and economic potential  

Microsoft Academic Search

Large-rock avalanche deposits are a common component of the basin fill within the extensional tectonic terrain of the Basin and Range; these deposits recently have been interpreted to host oil and gas within the Railroad Valley area of eastern Nevada. Large blocks of brecciated bedrock are a primary component of these avalanche deposits and are potentially excellent oil and gas

T. H. Morris; G. F. Hebertson

1996-01-01

66

Effect of large ion angular momentum spread and high current on inertial electrostatic confinement potential structures  

SciTech Connect

Prior Inertial Electrostatic Confinement (IEC) studies have assumed that very low angular momentum (zero in the ideal case) is necessary to achieve a potential well structure capable of trapping energetic ions in the center of a spherical device. However, the present study shows that high-current ion beams having large-angular-momentum spread can also form deep potential well traps.

Tzonev, I.V.; DeMora, J.M.; Miley, G.H. [Univ. of Illinois, Urbana, IL (United States)

1995-12-31

67

Effect of large ion angular momentum spread and high current on inertial electrostatic confinement potential structures  

Microsoft Academic Search

Prior inertial electrostatic confinement (IEC) studies have assumed that very low angular momentum (zero in the ideal case) is necessary to achieve a potential well structure capable of trapping energetic ions in the center of a spherical device. However, the present study shows that high-current ion beams having large-angular-momentum spread can also form deep potential well traps

Ivon V. Tzonev; John M. DeMora; George H. Miley

1995-01-01

68

Modelling potential changes in marine biogeochemistry due to large-scale offshore wind farms  

NASA Astrophysics Data System (ADS)

Large-scale renewable energy generation by offshore wind farms may lead to changes in marine ecosystem processes through the following mechanism: 1) wind-energy extraction leads to a reduction in local surface wind speeds; 2) these lead to a reduction in the local wind wave height; 3) as a consequence there's a reduction in SPM resuspension and concentrations; 4) this results in an improvement in under-water light regime, which 5) may lead to increased primary production, which subsequently 6) cascades through the ecosystem. A three-dimensional coupled hydrodynamics-biogeochemistry model (GETM_ERSEM) was used to investigate this process for a hypothetical wind farm in the central North Sea, by running a reference scenario and a scenario with a 10% reduction (as was found in a case study of a small farm in Danish waters) in surface wind velocities in the area of the wind farm. The ERSEM model included both pelagic and benthic processes. The results showed that, within the farm area, the physical mechanisms were as expected, but with variations in the magnitude of the response depending on the ecosystem variable or exchange rate between two ecosystem variables (3-28%, depending on variable/rate). Benthic variables tended to be more sensitive to the changes than pelagic variables. Reduced, but noticeable changes also occurred for some variables in a region of up to two farm diameters surrounding the wind farm. An additional model run in which the 10% reduction in surface wind speed was applied only for wind speeds below the generally used threshold of 25 m/s for operational shut-down showed only minor differences from the run in which all wind speeds were reduced. These first results indicate that there is potential for measurable effects of large-scale offshore wind farms on the marine ecosystem, mainly within the farm but for some variables up to two farm diameters away. However, the wave and SPM parameterisations currently used in the model are crude and need to be further tested and refined. Also, potential counter-acting processes such as possible increases in SPM concentrations due to turbulence generated by the wind-turbine foundations may need to be included for more accurate simulations. Moreover, it is unclear to what extent these results would be valid for areas where different hydrodynamic characteristics may predominate, e.g. with summer stratification or strong tidal currents. Finally, an assessment would need to be carried out of how beneficial or detrimental these potential changes might be from various social-economic and ecosystem-management points of view.

van der Molen, Johan; Rees, Jon; Limpenny, Sian

2013-04-01

69

Radiation-induced potential difference between electrodes with and without gamma rays  

NASA Astrophysics Data System (ADS)

Observation were carried out on the potential difference (PD) appearing between two electrodes immersed in solutions purged with Ar, CO 2, N 2O and O 2, where either one of the electrodes was subject to ?-ray irradiation. In the solutions with all other gases than N 2O, ionizing radiation incurred negative PDs; the electrode under ?-rays showed a potential less noble than the unirradiated one. In the case of O 2-purging, it was proved that the absolute value of PD was not as large as other examinations, and that a slightly negative PD value (-40 mV) remained even after a suspension of exposure. The experiments with variable loads between electrodes revealed that in the solution with N 2O the PD decreased with a much shallower gradient with an increase in current than in the solution with Ar and CO 2.

Fujita, Norihiko; Matsuura, Chihiro; Saigo, Kazuhiko

1997-03-01

70

Potential effects of large linear pipeline construction on soil and vegetation in ecologically fragile regions.  

PubMed

Long-distance pipeline construction results in marked human disturbance of the regional ecosystem and brings into question the safety of pipeline construction with respect to the environment. Thus, the direct environmental impact and proper handling of such large projects have received much attention. The potential environmental effects, however, have not been fully addressed, particularly for large linear pipeline projects, and the threshold of such effects is unclear. In this study, two typical eco-fragile areas in western China, where large linear construction projects have been conducted, were chosen as the case study areas. Soil quality indices (SQI) and vegetation indices (VI), representing the most important potential effects, were used to analyze the scope of the effect of large pipeline construction on the surrounding environment. These two indices in different buffer zones along the pipeline were compared against the background values. The analysis resulted in three main findings. First, pipeline construction continues to influence the nearby eco-environment even after a 4-year recovery period. During this period, the effect on vegetation due to pipeline construction reaches 300 m beyond the working area, and is much larger in distance than the effect on soil, which is mainly confined to within 30 m either side of the pipeline, indicating that vegetation is more sensitive than soil to this type of human disturbance. However, the effect may not reach beyond 500 m from the pipeline. Second, the scope of the effect in terms of distance on vegetation may also be determined by the frequency of disturbance and the intensity of the pipeline construction. The greater the number of pipelines in an area, the higher the construction intensity and the more frequent the disturbance. Frequent disturbance may expand the effect on vegetation on both sides of the pipeline, but not on soil quality. Third, the construction may eliminate the stable, resident plant community. During the recovery period, the plant community in the work area of the pipeline is replaced by some species that are rare or uncommon in the resident plant community because of human disturbance, thereby increasing the plant diversity in the work area. In terms of plant succession, the duration of the recovery period has a direct effect on the composition and structure of the plant community. The findings provide a theoretical basis and scientific foundation for improving the environmental impact assessment (EIA) of oil and gas pipeline construction as it pertains to the desert steppe ecosystem, and provide a reference point for recovery and management of the eco-environment during the pipeline construction period. PMID:25112841

Xiao, Jun; Wang, Ya-Feng; Shi, Peng; Yang, Lei; Chen, Li-Ding

2014-11-01

71

Potential climatic impacts and reliability of very large-scale wind farms  

NASA Astrophysics Data System (ADS)

Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG) emission technologies such as wind energy. The widespread availability of wind power has fueled substantial interest in this renewable energy source as one of the needed technologies. For very large-scale utilization of this resource, there are however potential environmental impacts, and also problems arising from its inherent intermittency, in addition to the present need to lower unit costs. To explore some of these issues, we use a three-dimensional climate model to simulate the potential climate effects associated with installation of wind-powered generators over vast areas of land or coastal ocean. Using wind turbines to meet 10% or more of global energy demand in 2100, could cause surface warming exceeding 1 °C over land installations. In contrast, surface cooling exceeding 1 °C is computed over ocean installations, but the validity of simulating the impacts of wind turbines by simply increasing the ocean surface drag needs further study. Significant warming or cooling remote from both the land and ocean installations, and alterations of the global distributions of rainfall and clouds also occur. These results are influenced by the competing effects of increases in roughness and decreases in wind speed on near-surface turbulent heat fluxes, the differing nature of land and ocean surface friction, and the dimensions of the installations parallel and perpendicular to the prevailing winds. These results are also dependent on the accuracy of the model used, and the realism of the methods applied to simulate wind turbines. Additional theory and new field observations will be required for their ultimate validation. Intermittency of wind power on daily, monthly and longer time scales as computed in these simulations and inferred from meteorological observations, poses a demand for one or more options to ensure reliability, including backup generation capacity, very long distance power transmission lines, and onsite energy storage, each with specific economic and/or technological challenges.

Wang, C.; Prinn, R. G.

2010-02-01

72

Whitefly control potential of Eretmocerus parasitoids with different reproductive modes  

Microsoft Academic Search

Whiteflies (Homoptera; Aleyrodidae) are amongst the key pests of vegetable, ornamental, and agronomic crops throughout the world. Because of failing and expensive chemical control, much research has been directed at developing biological control by searching for efficient natural enemies of whiteflies. Among different categories of natural enemies, parasitoids have been efficient control agents and cost effective. The aim of the

M. J. Ardeh

2005-01-01

73

Reduction of the field-aligned potential drop in the polar cap during large geomagnetic storms  

NASA Astrophysics Data System (ADS)

We have studied photoelectron flows and the inferred field-aligned potential drop in the polar cap during 5 large geomagnetic storms that occurred in the periods when the photoelectron observations in the polar cap were available near the apogee of the FAST satellite (~4000 km) at solar maximum, and the footprint of the satellite paths in the polar cap was under sunlit conditions most of the time. In contrast to the ~20 V potential drop during geomagnetically quiet periods at solar maximum identified by Kitamura et al. [JGR, 2012], the field-aligned potential drop frequently became smaller than ~5 V during the main and early recovery phases of the large geomagnetic storms. Because the potential acts to inhibit photoelectron escape, this result indicates that the corresponding acceleration of ions by the field-aligned potential drop in the polar cap and the lobe region is smaller during the main and early recovery phases of large geomagnetic storms compared to during geomagnetically quiet periods. Under small field-aligned current conditions, the number flux of outflowing ions should be nearly equal to the net escaping electron number flux. Since ions with large flux originating from the cusp/cleft ionosphere convect into the polar cap during geomagnetic storms [e.g., Kitamura et al., JGR, 2010], the net escaping electron number flux should increase to balance the enhanced ion outflows. The magnitude of the field-aligned potential drop would be reduced to let a larger fraction of photoelectrons escape.

Kitamura, N.; Seki, K.; Nishimura, Y.; Hori, T.; Terada, N.; Ono, T.; Strangeway, R. J.

2013-12-01

74

Interspecies Avian Brain Chimeras Reveal That Large Brain Size Differences Are Influenced by Cell  

E-print Network

Interspecies Avian Brain Chimeras Reveal That Large Brain Size Differences Are Influenced by Cell), and harvested the chimeras at later embryonic stages (between 9­12 days of incubation). The donor and host-C, Balaban E, Jarvis ED (2012) Interspecies Avian Brain Chimeras Reveal That Large Brain Size Differences

Jarvis, Erich D.

75

Identifying potential environmental impacts of large-scale deployment of dedicated bioenergy crops in the UK  

Microsoft Academic Search

Abstract There is momentum, globally, to increase the use of plant biomass for the production of heat, power and liquid transport fuels. This review assesses the evidence base for potential impacts of large-scale bioenergy crop deployment principally within the UK context, but with wider implications for Europe, the USA and elsewhere. We focus on second generation, dedicated lignocellulosic crops, but

Rebecca L. Rowe; Gail Taylor

2007-01-01

76

Identifying potential environmental impacts of large-scale deployment of dedicated bioenergy crops in the UK  

Microsoft Academic Search

There is momentum, globally, to increase the use of plant biomass for the production of heat, power and liquid transport fuels. This review assesses the evidence base for potential impacts of large-scale bioenergy crop deployment principally within the UK context, but with wider implications for Europe, the USA and elsewhere. We focus on second generation, dedicated lignocellulosic crops, but where

Rebecca L. Rowe; Gail Taylor

2009-01-01

77

PERSPECTIVES ON LARGE-SCALE NATURAL RESOURCES SURVEYS WHEN CAUSE-EFFECT IS A POTENTIAL ISSUE  

EPA Science Inventory

Our objective is to present a perspective on large-scale natural resource monitoring when cause-effect is a potential issue. We believe that the approach of designing a survey to meet traditional commodity production and resource state descriptive objectives is too restrictive an...

78

NYU researchers identify new potential therapeutic target for diffuse large B-cell lymphoma:  

Cancer.gov

Researchers from the NYU Cancer Institute, an NCI-designated cancer center at NYU Langone Medical Center, have discovered a new potential therapeutic target for Diffuse Large B-Cell Lymphoma (DLBCL), the most aggressive and common type of lymphoma in adults. The new study, published in the November 23 issue of Nature, reveals the underlying molecular mechanism contributing to the development of lymphomagenesis.

79

innovati nNREL Confirms Large Potential for Grid Integration of Wind, Solar Power  

E-print Network

innovati nNREL Confirms Large Potential for Grid Integration of Wind, Solar Power To fully harvest the nation's bountiful wind and solar resources, it is critical to know how much electrical power from penetrations of wind power. NREL is a national laboratory of the U.S. Department of Energy, Office of Energy

80

Didactic Problems in the Concept of Electric Potential Difference and an Analysis of its Philogenesis  

Microsoft Academic Search

This paper makes an analysis of the different didactic problems to come from the fact that electric charge is inseparable from the mass, the impossibility of its direct observation (only its effects) and the meaning associated with the basic concepts of electricity, like electric potential or electric potential difference.In order to know the origin of the different meaning found in

Enrique Jímenez Gomez; Eugenio Férnandez Duran

1998-01-01

81

Serber symmetry, large N{sub c}, and Yukawa-like one-boson exchange potentials  

SciTech Connect

The Serber force has relative orbital parity symmetry and requires vanishing NN interactions in partial waves with odd angular momentum. We illustrate how this property is well fulfilled for spin triplet states with odd angular momentum and violated for odd singlet states for realistic potentials but fails for chiral potentials. The analysis is carried out in terms of partial wave sum rules for NN phase shifts, r-space potentials at long distances, and V{sub lowk} potentials. We analyze how Serber symmetry can be accommodated within a large-N{sub c} perspective when interpreted as a long-distance symmetry. A prerequisite for this is the numerical similarity of the scalar and vector meson resonance masses. The conditions under which the resonance exchange potential can be approximated by a Yukawa form are also discussed. Although these masses arise as poles on the second Riemann in {pi}{pi} scattering, we find that within the large-N{sub c} expansion the corresponding Yukawa masses correspond instead to a well-defined large-N{sub c} approximation to the pole that cannot be distinguished from their location as Breit-Wigner resonances.

Calle Cordon, A.; Arriola, E. Ruiz [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain)

2009-07-15

82

Predicting Snow Velocity in Large Chute Flows Under Different Environmental Conditions  

E-print Network

Predicting Snow Velocity in Large Chute Flows Under Different Environmental Conditions Jonathan Rougier Department of Mathematics University of Bristol, UK Martin Kern Swiss Federal Institute for Snow, and expert judge- ments are combined to make predictions of snow velocity in large chute experiments

Oakley, Jeremy

83

Contribution potential of glaciers to water availability in different climate regimes  

PubMed Central

Although reliable figures are often missing, considerable detrimental changes due to shrinking glaciers are universally expected for water availability in river systems under the influence of ongoing global climate change. We estimate the contribution potential of seasonally delayed glacier melt water to total water availability in large river systems. We find that the seasonally delayed glacier contribution is largest where rivers enter seasonally arid regions and negligible in the lowlands of river basins governed by monsoon climates. By comparing monthly glacier melt contributions with population densities in different altitude bands within each river basin, we demonstrate that strong human dependence on glacier melt is not collocated with highest population densities in most basins. PMID:21059938

Kaser, Georg; Großhauser, Martin; Marzeion, Ben

2010-01-01

84

Comment on large gender difference on death anxiety in Arab countries.  

PubMed

In the recent interesting and excellent article by Abdel-Khalek (2) the large mean difference between Death Anxiety Scale (6) for males and females in Lebanon was noted. I have also noted such large differences in other studies with subjects in Arab countries (1, 3, 4). These studies and that of Abdel-Khalek (2) provide a total of 12 gender differences in four different countries--Egypt, Kuwait, Lebanon, and Libya. Although these large gender differences would be notable in comparison to those of most studies in the United States or other English-speaking countries, the comparison was made with the differences provided by the two studies that presented norms and norm-like information (5, 8). These two studies contain 12 pairs of means for both sexes. Eight of the 12 Arab difference means were higher than the highest American difference mean (chi 2 = 12.00, p less than .01). The reason(s) for the larger gender differences on death anxiety are not known, but it appears reasonable to suggest that in countries in which there are large sex-role differences that likely include bravery, men would be more expected to report lower death anxiety than women. Cross-cultural and demographic research with the recently developed Death Depression Scale (7) would likely yield interesting findings. PMID:1792289

Templer, D I

1991-12-01

85

Evaluating Potential for Large Releases from CO2 StorageReservoirs: Analogs, Scenarios, and Modeling Needs  

SciTech Connect

While the purpose of geologic storage of CO{sub 2} in deep saline formations is to trap greenhouse gases underground, the potential exists for CO{sub 2} to escape from the target reservoir, migrate upward along permeable pathways, and discharge at the land surface. Such discharge is not necessarily a serious concern, as CO{sub 2} is a naturally abundant and relatively benign gas in low concentrations. However, there is a potential risk to health, safety and environment (HSE) in the event that large localized fluxes of CO{sub 2} were to occur at the land surface, especially where CO{sub 2} could accumulate. In this paper, we develop possible scenarios for large CO{sub 2} fluxes based on the analysis of natural analogues, where large releases of gas have been observed. We are particularly interested in scenarios which could generate sudden, possibly self-enhancing, or even eruptive release events. The probability for such events may be low, but the circumstances under which they might occur and potential consequences need to be evaluated in order to design appropriate site selection and risk management strategies. Numerical modeling of hypothetical test cases is needed to determine critical conditions for such events, to evaluate whether such conditions may be possible at designated storage sites, and, if applicable, to evaluate the potential HSE impacts of such events and design appropriate mitigation strategies.

Birkholzer, Jens; Pruess, Karsten; Lewicki, Jennifer; Tsang,Chin-Fu; Karimjee, Anhar

2005-09-19

86

Gender Differences in Large-Scale Math Assessments: PISA Trend 2000 and 2003  

ERIC Educational Resources Information Center

Many efforts have been made to determine and explain differential gender performance on large-scale mathematics assessments. A well-agreed-on conclusion is that gender differences are contextualized and vary across math domains. This study investigated the pattern of gender differences by item domain (e.g., Space and Shape, Quantity) and item type…

Liu, Ou Lydia; Wilson, Mark

2009-01-01

87

oligomeric and polymeric DNA Large electrostatic differences in the binding thermodynamics of a cationic peptide to  

E-print Network

oligomeric and polymeric DNA Large electrostatic differences in the binding thermodynamics in part (figures, tables) or in entirety, see: Reprints www.pnas.org/misc/reprints.shtml To order reprints electrostatic differences in the binding thermodynamics of a cationic peptide to oligomeric and polymeric DNA

Lohman, Timothy M.

88

Modeling the large-scale water balance impact of different irrigation systems  

E-print Network

Modeling the large-scale water balance impact of different irrigation systems J. P. Evans1 and B. F. [1] In this study, two parameterizations for different irrigation techniques have been implemented­atmosphere interactions associated with traditional flood irrigation--a widespread but highly water-inefficient practice

Evans, Jason

89

Measurement of nasal potential difference in adult cystic fibrosis, Young's syndrome, and bronchiectasis  

Microsoft Academic Search

Previous work confirmed the abnormal potential difference between the undersurface of the inferior nasal turbinate and a reference electrode in cystic fibrosis, but the technique is difficult and the results show overlap between the cystic fibrosis and the control populations. In the present study the potential difference from the floor of the nose has therefore been assessed in normal subjects,

E W Alton; J G Hay; C Munro; D M Geddes

1987-01-01

90

Linking self-potential and geochemical signatures over a large porphyry mineral deposit in Alaska  

NASA Astrophysics Data System (ADS)

Geophysical and geochemical data collected during the 2007 and 2008 field campaigns at Pebble, a large Cu-Au-Mo porphyry deposit in southwest Alaska, are analyzed to help better understand the surface signatures associated with the deposit. In particular, we investigate the possible role of electrochemical transport associated with the "geobattery" created by the mineralized zone within the Earth's natural redox field. Several large self-potential anomalies, on the order of -600 mV and nearly 1 km in diameter, are consistent with the presence of a subsurface electrochemical cell. Source inversion of the self-potential data is used to determine the subsurface distribution of current sources associated with the cell, and is reconciled with the surface geochemical data. Additional constraints to the problem are provided by drill core information from exploratory drill holes, resistivity information from previous geophysical surveys, and information about regional groundwater elevations.

Minsley, B.; Eppinger, R. G.; Brown, P. J.

2008-12-01

91

Sagdeev potential approach for large amplitude compressional Alfvenic double layers in viscous plasmas  

SciTech Connect

Sagdeev’s technique is used to study the large amplitude compressional Alfvenic double layers in a magnetohydrodynamic plasma taking into account the small plasma ? and small values of kinematic viscosity. Dispersive effect raised by non-ideal electron inertia currents perpendicular to the ambient magnetic field. The range of allowed values of the soliton speed, M (Mach number), plasma ? (ratio of the plasma thermal pressure to the pressure in the confining magnetic field), and viscosity coefficient, wherein double layer may exist, are determined. In the absence of collisions, viscous dissipation modifies the Sagdeev potential and results in large amplitude compressional Alfvenic double layers. The depth of Sagdeev potential increases with the increasing Mach number and plasma ?, however, decreases with the increasing viscosity. The double layer structure increases with the increasing plasma ?, but decreases with increasing viscous dissipation ?(tilde sign)

Panwar, Anuraj; Rizvi, H.; Ryu, C. M. [Department of Physics, POSTECH, Hyoja-Dong San 31, Pohang, KyungBuk 790-784 (Korea, Republic of)] [Department of Physics, POSTECH, Hyoja-Dong San 31, Pohang, KyungBuk 790-784 (Korea, Republic of)

2013-11-15

92

Survival differences between peritoneal dialysis and hemodialysis among “large” ESRD patients in the United States  

Microsoft Academic Search

Survival differences between peritoneal dialysis and hemodialysis among “large” ESRD patients in the United States.BackgroundIt has been hypothesized that peritoneal dialysis compared to hemodialysis may be less effective in large patients with end-stage renal disease (ESRD).MethodsWe tested this hypothesis in a cohort of 134,728 new ESRD patients who were initiated on dialysis from May 1, 1995 to July 31, 1997

Austin G. Stack; Bhamidipati V. R. Murthy; Donald A. Molony

2004-01-01

93

Teaching about circuits at the introductory level: An emphasis on potential difference  

NASA Astrophysics Data System (ADS)

Introductory physics students often fail to develop a coherent conceptual model of electric circuits. In part, this failure occurs because the students did not develop a good understanding of the concept of electric potential. We describe an instructional approach that emphasizes the electric potential and the electric potential difference. Examples are given to illustrate this approach and how it differs from traditional treatments of these concepts. Assessment data is presented to suggest that this approach is successful in improving student understanding of electric potential and electric circuits.

Rosenthal, A. S.; Henderson, C.

2006-04-01

94

Comparison of regional stream and lake chemistry: Differences, similarities, and potential drivers  

E-print Network

, in general, the relative importance of inputs and processing differs in streams vs. lakes, and across streams), and no significant differences were found for N retention among lakes, streams, and wetlands after acComparison of regional stream and lake chemistry: Differences, similarities, and potential drivers

Lottig, Noah R.

95

Generation Mechanism of Earth Potential Difference Signal during Seismic Wave Propagation and its Observation Condition  

Microsoft Academic Search

We have observed the co-seismic electromagnetic phenomena such as earth potential difference (EPD) variation in many observation sites of both Miyagi and Akita Prefectures. So far, in any earthquakes we observed clear signals of the EPD variation. However, the amplitude of observed EPD signals are very different at each site. To explain this difference, firstly we assumed the EPD generation

Kan Okubo; Keisuke Yamamoto; Masakazu Takayama; Nobunao Takeuchi

2005-01-01

96

Development of a carbonate platform with potential for large discoveries - an example from Vietnam  

SciTech Connect

In offshore central and southern Vietnam a number of carbonate accumulations can be recognized. Platform carbonates form basin-wide units of carbonate characterized by strong, continuous parallel seismic reflectors. Facies are dominated by bioclastic wackestones with poor-moderate reservoir quality. On the more isolated highs, large buildups developed. These are typically 5-10 km across and 300 m thick. They unconformably overlie the platform carbonate facies which are extensively karstified. In places these are pinnacles, typically 2-5 km across, 300 m+ thick with chaotic or mounded internal seismic facies. The large carbonate buildups are characterized by steep sided slopes with talus cones, reef-margin rims usually developed around only part of the buildup, and a prominent back-stepping geometry. Buildup interior facies form the main potential reservoirs They are dominated by fine to coarse grained coralgal packstones. Fine grained carbonates are associated with deeper water events and multiple karst surfaces can also be identified. Reservoir quality is excellent, largely controlled by extensive dissolution and dolomitization believed to be related to the exposure events. Gas has been found in a number of reservoirs. Heterogeneities can be recognized which could potentially effect production. These include the extensive finer grained facies, cementation or open fissures associated with the karst surfaces, a more cemented reef rim, shallowing upwards facies cycles and faults.

Mayall, M.; Bent, A.; Dale, B. [BP/Statoil Alliance (Viet Nam)] [and others

1996-12-31

97

Development of a carbonate platform with potential for large discoveries - an example from Vietnam  

SciTech Connect

In offshore central and southern Vietnam a number of carbonate accumulations can be recognized. Platform carbonates form basin-wide units of carbonate characterized by strong, continuous parallel seismic reflectors. Facies are dominated by bioclastic wackestones with poor-moderate reservoir quality. On the more isolated highs, large buildups developed. These are typically 5-10 km across and 300 m thick. They unconformably overlie the platform carbonate facies which are extensively karstified. In places these are pinnacles, typically 2-5 km across, 300 m+ thick with chaotic or mounded internal seismic facies. The large carbonate buildups are characterized by steep sided slopes with talus cones, reef-margin rims usually developed around only part of the buildup, and a prominent back-stepping geometry. Buildup interior facies form the main potential reservoirs They are dominated by fine to coarse grained coralgal packstones. Fine grained carbonates are associated with deeper water events and multiple karst surfaces can also be identified. Reservoir quality is excellent, largely controlled by extensive dissolution and dolomitization believed to be related to the exposure events. Gas has been found in a number of reservoirs. Heterogeneities can be recognized which could potentially effect production. These include the extensive finer grained facies, cementation or open fissures associated with the karst surfaces, a more cemented reef rim, shallowing upwards facies cycles and faults.

Mayall, M.; Bent, A.; Dale, B. (BP/Statoil Alliance (Viet Nam)) (and others)

1996-01-01

98

Dendritic cells derived from pluripotent stem cells: Potential of large scale production  

PubMed Central

Human pluripotent stem cells (hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, are promising sources for hematopoietic cells due to their unlimited growth capacity and the pluripotency. Dendritic cells (DCs), the unique immune cells in the hematopoietic system, can be loaded with tumor specific antigen and used as vaccine for cancer immunotherapy. While autologous DCs from peripheral blood are limited in cell number, hPSC-derived DCs provide a novel alternative cell source which has the potential for large scale production. This review summarizes recent advances in differentiating hPSCs to DCs through the intermediate stage of hematopoietic stem cells. Step-wise growth factor induction has been used to derive DCs from hPSCs either in suspension culture of embryoid bodies (EBs) or in co-culture with stromal cells. To fulfill the clinical potential of the DCs derived from hPSCs, the bioprocess needs to be scaled up to produce a large number of cells economically under tight quality control. This requires the development of novel bioreactor systems combining guided EB-based differentiation with engineered culture environment. Hence, recent progress in using bioreactors for hPSC lineage-specific differentiation is reviewed. In particular, the potential scale up strategies for the multistage DC differentiation and the effect of shear stress on hPSC differentiation in bioreactors are discussed in detail. PMID:24567783

Li, Yan; Liu, Meimei; Yang, Shang-Tian

2014-01-01

99

Large age differences between planktic foraminifers caused by abundance variations and Zoophycos bioturbation  

NASA Astrophysics Data System (ADS)

The downward transport of surface sediment deep into the sediment column by the Zoophycos-producing animal leads not only to large age differences between the Zoophycos structure and surrounding host sediment but also to large differences in age between different foraminifer species found inside the trace fossil. In the late Quaternary material from the southwestern Portuguese continental slope examined in this study, age differences of up to 2590 years were observed between the planktic foraminifer species Globigerinoides ruber and Globigerina bulloides. These differences are caused by the mixing of surface and host material with different abundances of the two species. If there are differences in the abundance of the two species at the surface and/or in the host sediment, plenty of relatively young foraminifers may be mixed with few relatively old ones, or vice versa. The age differences between species caused by the combination of deep-reaching bioturbation by the Zoophycos producer and abundance variations may be considerably larger than the age differences caused by the homogenizing bioturbation in the mixed layer.

LöWemark, Ludvig; Grootes, Pieter M.

2004-06-01

100

Infants Use Different Mechanisms to Make Small and Large Number Ordinal Judgments  

ERIC Educational Resources Information Center

Previous research has shown indirectly that infants may use two different mechanisms-an object tracking system and an analog magnitude mechanism--to represent small (less than 4) and large (greater than or equal to 4) numbers of objects, respectively. The current study directly tested this hypothesis in an ordinal choice task by presenting 10- to…

vanMarle, Kristy

2013-01-01

101

Similarities and differences in small and large corporation beliefs about capital structure policy  

Microsoft Academic Search

Theoretical researchers posit many factors that affect a firm's capital structure decisions. Theory also suggests that these influences will have different impacts on small and large firms. However, empiricists face difficulties in testing these hypotheses due to problems of quantifying the motivations, expectations, and preferences prevalent in the various theories.

Edgar Norton

1990-01-01

102

Accurate measurement of large optical frequency differences with a mode-locked laser  

Microsoft Academic Search

We have used the comb of optical frequencies emitted by a mode-locked laser as a ruler to measure differences of as much as 20 THz between laser frequencies. This is to our knowledge the largest gap measured with a frequency comb, with high potential for further improvements. To check the accuracy of this approach we show that the modes are

J. Reichert; R. Holzwarth; T. W. Hänsch

1999-01-01

103

Large-rock avalanche deposits, eastern Basin and Range, Utah: Emplacement, diagenesis, and economic potential  

SciTech Connect

Large-rock avalanche deposits are a common component of the basin fill within the extensional tectonic terrain of the Basin and Range; these deposits recently have been interpreted to host oil and gas within the Railroad Valley area of eastern Nevada. Large blocks of brecciated bedrock are a primary component of these avalanche deposits and are potentially excellent oil and gas reservoirs. Our work provides further insight into the emplacement and economic potential of these deposits. Exposed large-rock avalanche deposits of the Miocene Oak City Formation on the western margin of the Canyon Range, Utah, contain coherent breccia blocks up to 3.5 km long, 1 km wide, and 200 m thick. These deposits were derived from the near-vertical dipping bed rock of the adjacent Canyon Range and now are exposed as much as 5.5 km from the range front within the Sevier Desert basin. Emplacement was relatively rapid, as indicated by three well-developed breccia facies within the carbonate breccia blocks. Stratigraphically, from the base the facies include (1) matrix-rich breccia, (2) jigsaw breccia, and (3) crackle breccia. The deposits were cut and segmented by a series of syn-depositional normal faults that developed during late Miocene and post-Miocene extension. Primary porosity was reduced by cement soon after burial. Cathodoluminescence cement patterns indicate that initially the basinward breccia blocks were more deeply buried relative to the water table than the breccia blocks proximal to the Canyon Range. After initial cementation, the basinward blocks were uplifted relative to the water table. Secondary porosity approaches 8% in the carbonate blocks and is greater than 14% within the jigsaw breccia. The size and porosity of these breccia blocks indicate their potential as reservoir targets.

Morris, T.H.; Hebertson, G.F. [Brigham Young Univ., Provo, Utah (United States)

1996-07-01

104

Use of an Automatic Methane Potential Test System for evaluating the biomethane potential of sugarcane bagasse after different treatments.  

PubMed

A multi-channel analyzer was used to evaluate biogas potential of sugarcane bagasse (SCB). The Automatic Methane Potential Test System contained fifteen parallel reactors and the same number of gas flow meters attached to the acquisition system. The set of reactors - gas flow meters gave reproducible results during anaerobic digestion of chemically defined carbon source and the units were used to evaluate the biomethane potential of SCB after different pretreatments, such as treatment with water, acid, acid followed by enzymatic treatment and acid followed by treatment with inactive enzymes. Combined pretreatment with 2% sulphuric acid and enzymatic hydrolysis (3.5% enzymes) resulted in conversion of 79% to monomeric sugars present in SCB. SCB treated with acid followed by enzymatic hydrolysis achieved the methane yield of 200 NL per kg VS(added). Enzymatic saccharification of acid pretreated SCB resulted in increase of methane yield by 16±5% compared to that from acid treated SCB. PMID:22446055

Badshah, Malik; Lam, Duong Minh; Liu, Jing; Mattiasson, Bo

2012-06-01

105

Submm/FIR astronomy in Antarctica: Potential for a large telescope facility  

E-print Network

Preliminary site testing datasets suggest that Dome C in Antarctica is one of the best sites on Earth for astronomical observations in the 200 to 500 micron regime, i.e. for far-infrared (FIR) and submillimetre (submm) astronomy. We present an overview of potential science cases that could be addressed with a large telescope facility at Dome C. This paper also includes a presentation of the current knowledge about the site characterics in terms of atmospheric transmission, stability, sky noise and polar constraints on telescopes. Current and future site testing campaigns are finally described.

Vincent Minier; V. Minier; L. Olmi; P. -O. Lagage; L. Spinoglio; G. A. Durand; E. Daddi; D. Galilei; H. Gallee; C. Kramer; D. Marrone; E. Pantin; L. Sabbatini; N. Schneider; N. Tothill; L. Valenziano; C. Veyssiere

2008-05-16

106

Vascular large conductance calcium-activated potassium channels: Functional role and therapeutic potential  

Microsoft Academic Search

Large-conductance Ca2+-activated K+ channels (BKCa or maxiK channels) are expressed in different cell types. They play an essential role in the regulation of various cell functions.\\u000a In particular, BKCa channels have been extensively studied in vascular smooth muscle cells, where they contribute to the control of vascular\\u000a tone. They facilitate the feedback regulation against the rise of intracellular Ca2+, membrane

Birgit Eichhorn; Dobromir Dobrev

2007-01-01

107

Analytical solitary-wave solutions of the generalized nonautonomous cubic-quintic nonlinear Schroedinger equation with different external potentials  

SciTech Connect

A large family of analytical solitary wave solutions to the generalized nonautonomous cubic-quintic nonlinear Schroedinger equation with time- and space-dependent distributed coefficients and external potentials are obtained by using a similarity transformation technique. We use the cubic nonlinearity as an independent parameter function, where a simple procedure is established to obtain different classes of potentials and solutions. The solutions exist under certain conditions and impose constraints on the coefficients depicting dispersion, cubic and quintic nonlinearities, and gain (or loss). We investigate the space-quadratic potential, optical lattice potential, flying bird potential, and potential barrier (well). Some interesting periodic solitary wave solutions corresponding to these potentials are then studied. Also, properties of a few solutions and physical applications of interest to the field are discussed. Finally, the stability of the solitary wave solutions under slight disturbance of the constraint conditions and initial perturbation of white noise is discussed numerically; the results reveal that the solitary waves can propagate in a stable way under slight disturbance of the constraint conditions and the initial perturbation of white noise.

He Junrong; Li Huamei [Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China)

2011-06-15

108

Dorsolateral medullary infarction: a neurogenic cause of a contralateral, large-amplitude vestibular evoked myogenic potential.  

PubMed

The vestibular evoked myogenic potential (VEMP) has become a useful tool to assess the saccule and inferior vestibular nerve function. Vestibulopathies involving the saccule or inferior vestibular nerve typically result in VEMP responses that are diminished or absent on the involved side. Abnormally large VEMPs are rare. Large VEMPs have been associated with superior canal dehiscence, Ménière's disease, and labyrinthine fistula. In all of these cases, the abnormally large VEMP can be explained on the basis of labyrinthine hydromechanical changes that result in excessive saccular displacement in response to intense sound. In this report, a case is presented of a 74-year-old male with dorsal lateral medullary infarction (Wallenberg's syndrome) who presented with an enlarged VEMP--a finding that has not been reported to date as a result of a brain stem lesion. Particularly perplexing, the enlarged VEMP was on the contralesional side. A proposed mechanism of contralateral vestibular nuclei disinhibition secondary to the brain stem stroke is discussed. PMID:18672653

Lundy, Larry; Zapala, David; Olsholt, Ketil

2008-03-01

109

Potential for on-orbit manufacture of large space structures using the pultrusion process  

NASA Technical Reports Server (NTRS)

On-orbit manufacture of lightweight, high-strength, advanced-composite structures using the pultrusion process is proposed. This process is adaptable to a zero-gravity environment by using preimpregnated graphite-fiber reinforcement systems. The reinforcement material is preimpregnated with a high-performance thermoplastic resin at a ground station, is coiled on spools for compact storage, and is transported into Earth orbit. A pultrusion machine is installed in the Shuttle cargo bay from which very long lengths of the desired structure is fabricated on-orbit. Potential structural profiles include rods, angles, channels, hat sections, tubes, honeycomb-cored panels, and T, H, and I beams. A potential pultrudable thermoplastic/graphite composite material is presented as a model for determining the effect on Earth-to-orbit package density of an on-orbit manufacture, the package density is increased by 132 percent, and payload volume requirement is decreased by 56.3 percent. The fabrication method has the potential for on-orbit manufacture of structural members for space platforms, large space antennas, and long tethers.

Wilson, Maywood L.; Macconochie, Ian O.; Johnson, Gary S.

1987-01-01

110

Automated system for identifying potential dosage problems at a large university hospital.  

PubMed

A hospital's experience with an automated system for screening drug orders for potential dosage problems is described. DoseChecker was developed by the hospital pharmacy department in collaboration with a local university. Pharmacy, laboratory, and patient demographic data are transferred nightly from the hospital's mainframe system to a database server; DoseChecker uses these data and user-defined rules to (1) identify patients receiving any of 35 targeted medications, (2) evaluate the appropriateness of current dosages, and (3) generate alerts for patients potentially needing dosage adjustments. The alert reports are distributed to satellite pharmacists, who evaluate each patient's condition and make recommendations to physicians as needed. One of the system's primary purposes is to calculate creatinine clearance and verify that dosages are properly adjusted for renal function. Between May and October 1995, the system electronically screened 28,528 drug orders and detected potential dosage problems in 2859 (10%). The system recommended a lower daily dose in 1992 cases (70%) and a higher daily dose in 867 (30%). Pharmacists contacted physicians concerning 1163 (41%) of the 2859 alerts; in 868 cases (75%), the physicians agreed to adjust the dosage. The most common dosage problem identified was failure to adjust dosages on the basis of declining renal function. An automated system provided an efficient method of identifying inappropriate dosages at a large university hospital. PMID:9066863

McMullin, S T; Reichley, R M; Kahn, M G; Dunagan, W C; Bailey, T C

1997-03-01

111

Sex Differences on "g" and Non-"g" Intellectual Performance Reveal Potential Sources of STEM Discrepancies  

ERIC Educational Resources Information Center

The analysis of sex differences in cognitive abilities is largely confusing because these differences are masked by the pervasive influence of the general factor of intelligence (g). In this study a battery of five reasoning tests (abstract [AR], numerical [NR], verbal [VR], mechanical [MR], and spatial [SR]) was completed by a sample of 3233…

Lemos, Gina C.; Abad, Francisco J.; Almeida, Leandro S.; Colom, Roberto

2013-01-01

112

Temporal-spatial changes in Sonic Hedgehog expression and signaling reveal different potentials of ventral  

E-print Network

Temporal-spatial changes in Sonic Hedgehog expression and signaling reveal different potentials ARTICLE Open Access Temporal-spatial changes in Sonic Hedgehog expression and signaling reveal different mesencephalic precursors that express Sonic Hedgehog (Shh). However, Shh expression, which is initially confined

Paris-Sud XI, Université de

113

How Teachers and Schools Contribute to Racial Differences in the Realization of Academic Potential  

ERIC Educational Resources Information Center

Background/Context: The fulfillment of academic potential is an underdeveloped area of inquiry as it relates to explaining racial differences in academic outcomes. Examining this issue is important for addressing not only differences in the typical outcomes for African American and White students but also the severe underrepresentation of African…

Wildhagen, Tina

2012-01-01

114

Intra- and Interspecific Differences in Diet Quality and Composition in a Large Herbivore Community  

PubMed Central

Species diversity in large herbivore communities is often explained by niche segregation allowed by differences in body mass and digestive morphophysiological features. Based on large number of gut samples in fall and winter, we analysed the temporal dynamics of diet composition, quality and interspecific overlap of 4 coexisting mountain herbivores. We tested whether the relative consumption of grass and browse differed among species of different rumen types (moose-type and intermediate-type), whether diet was of lower quality for the largest species, whether we could identify plant species which determined diet quality, and whether these plants, which could be “key-food-resources” were similar for all herbivores. Our analyses revealed that (1) body mass and rumen types were overall poor predictors of diet composition and quality, although the roe deer, a species with a moose-type rumen was confirmed as an “obligatory non grazer”, while red deer, the largest species, had the most lignified diet; (2) diet overlap among herbivores was well predicted by rumen type (high among species of intermediate types only), when measured over broad plant groups, (3) the relationship between diet composition and quality differed among herbivore species, and the actual plant species used during winter which determined the diet quality, was herbivore species-specific. Even if diets overlapped to a great extent, the species-specific relationships between diet composition and quality suggest that herbivores may select different plant species within similar plant group types, or different plant parts and that this, along with other behavioural mechanisms of ecological niche segregation, may contribute to the coexistence of large herbivores of relatively similar body mass, as observed in mountain ecosystems. PMID:24586233

Redjadj, Claire; Darmon, Gaëlle; Maillard, Daniel; Chevrier, Thierry; Bastianelli, Denis; Verheyden, Hélène; Loison, Anne; Saïd, Sonia

2014-01-01

115

Collision between immiscible drops with large surface tension difference: diesel oil and water  

NASA Astrophysics Data System (ADS)

The collision outcomes of immiscible drops with large surface tension difference, namely, a water drop and a diesel oil drop, were observed experimentally. In a near head-on collision between immiscible drops with large surface tension difference, an “overlaying” action for the drop of the smaller surface tension, i.e., the diesel oil drop, to go around the surface of the drop of the larger surface tension, i.e., the water drop, occurs during the collision. This overlaying action reduces the reflex energy for head-on collisions, making reflex separation more difficult to occur. At the same time, due to the immiscibility, the liquid bridge during stretching separation becomes narrower, which makes stretching separation easier to happen. No coalescence could be observed for a collision of Weber number greater than 60. In addition, compound drops are produced frequently.

Chen, Rong-Horng; Chen, Chiu-Ting

2006-09-01

116

Gender differences in academic performance in a large public university in Turkey  

Microsoft Academic Search

The paper attempts to determine whether there are significant gender differences in academic performance among undergraduate\\u000a students in a large public university in Turkey based on three indicators; university entrance scores, performance in the\\u000a English preparatory school and in the program the student is majoring in. The paper finds that a smaller number of female\\u000a students manage to enter the

Meltem Dayio?lu; Serap Türüt-A?ik

2007-01-01

117

Analysis of an ECG Record Database Reveals QT Interval Prolongation Potential of Famotidine in a Large Korean Population.  

PubMed

Some non-antiarrhythmic drugs have the undesirable property of delaying cardiac repolarization, an effect that can be measured empirically as a prolongation of the QT interval by surface electrocardiogram (ECG). The QT prolongation and proarrhythmia potential of famotidine are largely unknown, particularly in individuals that have cardiovascular risk factors such as abnormal electrolyte levels. Based on an analysis of QT/QTc intervals from a database of ECG recordings from a large Korean population (ECG-ViEW, 710,369 ECG recordings from 371,401 individuals), we observed that famotidine administration induced a prolonged QTc interval (above 480 ms, p < 0.05 compared to before-treatment, based on a McNemar test). Furthermore, famotidine induced QT prolongations in 10 out of 14 patients with hypocalcemia and 11 out of 13 patients with hypomagnesemia [difference of mean between before and after famotidine administration; 38.00 ms (95 % confidence interval 2.72-73.28) and 67.08 ms (95 % confidence interval 24.94-109.21), p < 0.05 and p < 0.01 by paired t test, respectively]. In vitro, the IC50 of famotidine for human-ether-a-go-go gene (hERG) channel inhibition was higher than 100 ?M as determined by automated patch clamp hERG current assay, implying that hERG channel inhibition is not the underlying mechanism for QT prolongation. These results suggest that famotidine administration increases a proarrhythmic potential, especially in subjects with electrolytes imbalance. PMID:25253561

Yun, Jaesuk; Hwangbo, Eun; Lee, Jongpill; Chon, Chong-Run; Kim, Peol A; Jeong, In-Hye; Park, Manyoung; Park, Raewoong; Kang, Shin-Jung; Choi, Donwoong

2015-04-01

118

Gender Differences in Sexual Attitudes and Behaviors: A Review of Meta-Analytic Results and Large Datasets  

Microsoft Academic Search

Gender differences in sexual attitudes and behaviors are typically believed to be large, yet recent evidence suggests that some gender differences in sexuality are much smaller than common knowledge would suggest. This article reviews gender differences in sexual attitudes and behaviors as reported by major meta-analyses and large datasets. In particular, this article reviews gender differences in heterosexual intercourse, masturbation,

Jennifer L. Petersen; Janet Shibley Hyde

2011-01-01

119

Cancer stem cells display extremely large evolvability: alternating plastic and rigid networks as a potential mechanism  

E-print Network

Cancer is increasingly perceived as a systems-level, network phenomenon. The major trend of malignant transformation can be described as a two-phase process, where an initial increase of network plasticity is followed by a decrease of plasticity at late stages of tumor development. The fluctuating intensity of stress factors, like hypoxia, inflammation and the either cooperative or hostile interactions of tumor inter-cellular networks, all increase the adaptation potential of cancer cells. This may lead to the bypass of cellular senescence, and to the development of cancer stem cells. We propose that the central tenet of cancer stem cell definition lies exactly in the indefinability of cancer stem cells. Actual properties of cancer stem cells depend on the individual "stress-history" of the given tumor. Cancer stem cells are characterized by an extremely large evolvability (i.e. a capacity to generate heritable phenotypic variation), which corresponds well with the defining hallmarks of cancer stem cells: the...

Csermely, Peter; Korcsmaros, Tamas; Modos, Dezso; Perez-Lopez, Aron R; Szalay, Kristof; Veres, Daniel V; Lenti, Katalin; Wu, Ling-Yun; Zhang, Xiang-Sun

2013-01-01

120

On the energy integral formulation of gravitational potential differences from satellite-to-satellite tracking  

NASA Astrophysics Data System (ADS)

Two approaches have been formulated to compute the gravitational potential difference using low-low satellite-to-satellite tracking data based on energy integral: one in the geocentric inertial reference system, and the other in the terrestrial reference system. The focus of this work is on the approach in the geocentric inertial reference system, where a potential rotation term appears in addition to the potential term. In former formulations, the contribution of the time-variable components of the gravitational potential to the potential term was included, but their contribution to the potential rotation term was neglected. In this work, an improvement to the former formulations is made by reformulating the potential rotation term to include the contribution of the time-variable components of the gravitational potential. A simulation shows that our more accurate formulation of the potential rotation term is necessary to achieve the accuracy for recovering the temporal variation of the Earth's gravity field, such as for use to the Gravity Recovery And Climate Experiment GRACE observation data based on this approach.

Guo, J. Y.; Shang, K.; Jekeli, C.; Shum, C. K.

2015-04-01

121

In vitro evaluation of UV opacity potential of Aloe vera L. gel from different germplasms  

Microsoft Academic Search

In this study, lyophilized crude and methanolic extracts of aloe gel from different germplasms (S24, RM, TN, OR, and RJN)\\u000a of Aloe vera L. were tested for their ultraviolet (UV) opacity potential. UV absorption profiles, sun protection factor (SPF), and percentage\\u000a blocking of UVA and UVB were considered to test UV opacity potential. Both the extracts showed UV absorption and

M. Shyam Kumar; P. K. Datta; S. Dutta Gupta

2009-01-01

122

Anaerobic treatability and biogas production potential studies of different agro-industrial wastewaters in Turkey  

Microsoft Academic Search

The anaerobic treatability and methane generation potential of the wastewaters of the three important agro-industries in Turkey, namely, cheese-making, poultry breeding and the olive-oil mill industries were studied. Biochemical methane potential (BMP) experiments were conducted for different initial chemical oxygen demand (COD) concentrations. The results indicate that anaerobic treatment was possible for all the wastewaters studied and the biogas produced

Göksel N. Demirer; Metin Duran; Engin Güven; Örgen Ugurlu; Ulas Tezel; Tuba H. Ergüder

2000-01-01

123

Relevant distance between two different instances of the same potential energy in protein folding  

E-print Network

In the context of complex systems and, particularly, of protein folding, a physically meaningful distance is defined which allows to make useful statistical statements about the way in which energy differences are modified when two different instances of the same potential-energy function are used. When the two instances arise from the fact that different algorithms or different approximations are used, the distance herein defined may be used to evaluate the relative accuracy of the two methods. When the difference is due to a change in the free parameters of which the potential depends on, the distance can be used to quantify, in each region of parameter space, the robustness of the modeling to such a change and this, in turn, may be used to assess the significance of a parameters' fit. Both cases are illustrated with a practical example: the study of the Poisson-based solvation energy in the Trp-Cage protein (PDB code 1L2Y).

Jose Luis Alonso; Pablo Echenique

2005-04-21

124

Large climate-moderating envelopes for enclosed structures: a preliminary evaluation of energy conservation potential  

SciTech Connect

An investigation was made of the basic impacts of putting a large secondary enclosure around a number of functions and thereby creating a Large Climate Moderating Envelope (LCME). This study is a preliminary estimate of the energy conservation benefits of an LCME. A hypothetical LMCE design was chosen and a coupled fluid dynamic and energy transport analysis was performed to estimate the energy conservation potential of this design. The heat transfer models included insolation, outside air temperature and wind, thermal radiation exchange with the sky, and between the fabric and ground and thermal storage in the earth mass beneath the LCME. The energy transported within the fluid by the buoyancy driven circulation was modeled as an incompressible fluid utilizing the Boussinesq approximation. The climatic conditions were assumed to vary in smooth repeating daily cycles. The numerical simulation of climatic variation was continued until the results within the LCME achieved a repeating daily cycle. The results for selected seasonally characteristic days were utilized to estimate the annual energy consumption of structures within an LCME relative to similar structures exposed to the exterior environment. The relative annual energy savings for summer-dominated climates was estimated to be approx. 70%. The energy savings for a winter-dominated climate LCME were estimated to be somewhat smaller but the LCME concept could offer significant benefits for agricultural applications for this type of climate.

Wendt, R.L.; Giles, G.E.; Park, J.E.

1981-12-01

125

Dimer-dimer scattering length for fermions with different masses: Analytical study for large mass ratio  

NASA Astrophysics Data System (ADS)

We study the dimer-dimer scattering length a4 for a two-component Fermi mixture in which the different fermions have different masses m? and m?. This is made in the framework of the exact field-theoretic method. In the large mass ratio domain the equations are simplified enough to lead to an analytical solution. In particular we link a4 to the fermion-dimer scattering length a3 for the same fermions and obtain the very simple relation a4=a3/2. The result a4?a3/2 is actually valid whatever the mass ratio with quite good precision. As a result we find an analytical expression providing a4 with fairly good precision for any mass. To dominant orders for large mass ratio it agrees with the literature. We show that in this large mass ratio domain, the dominant processes are the repeated dimer-dimer Born scatterings, considered earlier by Pieri and Strinati [Phys Rev. B10.1103/PhysRevB.61.15370 61, 15370 (2000)]. We conclude that their approximation of retaining only these processes is a fairly good one whatever the mass ratio.

Alzetto, F.; Combescot, R.; Leyronas, X.

2013-02-01

126

Large differences in reanalyses of diabatic heating in the tropical upper troposphere and lower stratosphere  

NASA Astrophysics Data System (ADS)

We present the time mean heat budgets of the tropical upper troposphere (UT) and lower stratosphere (LS) as simulated by five reanalysis models: the Modern-Era Retrospective Analysis for Research and Applications (MERRA), European Reanalysis (ERA-Interim), Climate Forecast System Reanalysis (CFSR), Japanese 25-yr Reanalysis and Japan Meteorological Agency Climate Data Assimilation System (JRA-25/JCDAS), and National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis 1. The simulated diabatic heat budget in the tropical UTLS differs significantly from model to model, with substantial implications for representations of transport and mixing. Large differences are apparent both in the net heat budget and in all comparable individual components, including latent heating, heating due to radiative transfer, and heating due to parameterised vertical mixing. We describe and discuss the most pronounced differences. Discrepancies in latent heating reflect continuing difficulties in representing moist convection in models. Although these discrepancies may be expected, their magnitude is still disturbing. We pay particular attention to discrepancies in radiative heating (which may be surprising given the strength of observational constraints on temperature and tropospheric water vapour) and discrepancies in heating due to turbulent mixing (which have received comparatively little attention). The largest differences in radiative heating in the tropical UTLS are attributable to differences in cloud radiative heating, but important systematic differences are present even in the absence of clouds. Local maxima in heating and cooling due to parameterised turbulent mixing occur in the vicinity of the tropical tropopause.

Wright, J. S.; Fueglistaler, S.

2013-09-01

127

Commercial processed food may have endocrine-disrupting potential: soy-based ingredients making the difference.  

PubMed

Processed and packaged food items as well as ready-to-eat snacks are neglected and poorly characterised sources of human exposure to endocrine-disrupting chemicals (EDCs). In this study we investigated the presence of xenoestrogens in commercially processed and packaged Finnish foods, arising from substances deliberately added or inadvertently contaminating the food, substances formed as a result of food processing, or substances leaching from food packaging materials. Samples were obtained in three separate batches of equivalent products from both a supermarket and a local representative of a global chain of hamburger restaurants and extracted by a solid-phase extraction method. Their endocrine-disrupting potential was determined by yeast bioluminescent assay, using two recombinant yeast strains Saccharomyces cerevisiae BMAEREluc/ER? and S. cerevisiae BMA64/luc. In this test system, the majority of samples (both foodstuffs and wrappers) analysed proved negative. However, all batches of industrially prepared hamburgers (but not those obtained from a hamburger restaurant) as well as pepper salami significantly induced luciferase activity in the BMAEREluc/ER? yeast strain indicating the presence of xenoestrogens, with estradiol equivalents of these products ranging from 0.2 to 443 pg g(-1). All three products contained soy-based ingredients, which apparently accounted for, or at least contributed to, their high estrogenic activity, since no signal in the assay was observed with extracts of the packaging material, while two different soy sauces tested yielded an intense signal (28 and 54 pg ml(-1) estradiol-equivalent). These findings imply that by and large chemicals arising in the processing or packaging of foodstuffs in Finland constitute an insignificant source of xenoestrogens to consumers. However, soy-derived ingredients in certain food items might render the entire products highly estrogenic. The estrogenic activity of soy is attributed to isoflavones whose health effects - though widely considered beneficial - are controversial. As hamburgers are a popular type of food among children, the findings are noteworthy and possibly of concern. PMID:23886479

Omoruyi, Iyekhoetin Matthew; Kabiersch, Grit; Pohjanvirta, Raimo

2013-01-01

128

Motivation by potential gains and losses affects control processes via different mechanisms in the attentional network.  

PubMed

Attentional control in demanding cognitive tasks can be improved by manipulating the motivational state. Motivation to obtain gains and motivation to avoid losses both usually result in faster reaction times and stronger activation in relevant brain areas such as the prefrontal cortex, but little is known about differences in the underlying neurocognitive mechanisms of these types of motivation in an attentional control context. In the present functional magnetic resonance imaging (fMRI) study, we tested whether potential gain and loss as motivating incentives lead to overlapping or distinct neural effects in the attentional network, and whether one of these conditions is more effective than the other. A Flanker task with word stimuli as targets and distracters was performed by 115 healthy participants. Using a mixed blocked and event-related design allowed us to investigate transient and sustained motivation-related effects. Participants could either gain money (potential gain) or avoid losing money (potential loss) in different task blocks. Participants showed a congruency effect with increased reaction times for incongruent compared to congruent trials. Potential gain led to generally faster responses compared to the neutral condition and to stronger improvements than potential loss. Potential loss also led to shorter response times compared to the neutral condition, but participants improved mainly during incongruent and not during congruent trials. The event-related fMRI data revealed a main effect of congruency with increased activity in the left inferior frontal gyrus (IFG) and inferior frontal junction area (IFJ), the pre-supplementary motor area (pre-SMA), bilateral insula, intraparietal sulcus (IPS) and visual word form area (VWFA). While potential gain led to increased activity in a cluster of the IFJ and the VWFA only during incongruent trials, potential loss was linked to activity increases in these regions during incongruent and congruent trials. The block analysis revealed greater activity in gain and loss blocks compared to the neutral condition in most of these regions but no differences in the direct comparison of gain and loss blocks. These findings show that potential monetary gain and loss rely on different mechanisms: Gain was more effective in reducing the reaction time compared to potential loss. Brain data indicate that in the gain context attentional control is executed specifically in incongruent trials, whereas the loss context induces an unspecific increase of attentional control. These findings extend previous studies by providing evidence for diverging neural mechanisms for the effects of different types of motivation on attentional control, specifying the underlying activity patterns in task- and stimulus-related regions. PMID:25731995

Paschke, Lena M; Walter, Henrik; Steimke, Rosa; Ludwig, Vera U; Gaschler, Robert; Schubert, Torsten; Stelzel, Christine

2015-05-01

129

Impact of Potential Large-Scale Irrigation on the West African Monsoon and Its Dependence on Location of Irrigated Area  

E-print Network

This study investigates the impact of potential large-scale irrigation on the West African monsoon using the Massachusetts Institute of Technology regional climate model (MRCM). A new irrigation module is implemented to ...

Im, Eun-Soon

130

A conservative implicit finite difference algorithm for the unsteady transonic full potential equation  

NASA Technical Reports Server (NTRS)

An implicit finite difference procedure is developed to solve the unsteady full potential equation in conservation law form. Computational efficiency is maintained by use of approximate factorization techniques. The numerical algorithm is first order in time and second order in space. A circulation model and difference equations are developed for lifting airfoils in unsteady flow; however, thin airfoil body boundary conditions have been used with stretching functions to simplify the development of the numerical algorithm.

Steger, J. L.; Caradonna, F. X.

1980-01-01

131

Metabolic efficiency of Geobacter sulfurreducens growing on anodes with different redox potentials.  

PubMed

Microorganisms respiring Fe(III) in the environment face a range of redox potentials of the prospective terminal ferric electron acceptors, because Fe(III) can be present in different minerals or organic complexes. We investigated the adaptation of Geobacter sulfurreducens to this range by exposing the bacteria to different redox potentials between the electron donor acetate and solid, extracellular anodes in a microbial fuel-cell set-up. Over a range of anode potentials from -0.105 to +0.645 V versus standard hydrogen electrode, G. sulfurreducens produced identical amounts of biomass per electron respired. This indicated that the organism cannot utilize higher available energies for energy conservation to ATP, and confirmed recent studies. Either the high potentials cannot be used due to physiological limitations, or G. sulfurreducens decreased its metabolic efficiency, and less biomass per unit of energy was produced. In this case, G. sulfurreducens "wasted" energy at high-potential differences, most likely as heat to fuel growth kinetics. PMID:24554342

Bosch, Julian; Lee, Keun-Young; Hong, Siang-Fu; Harnisch, Falk; Schröder, Uwe; Meckenstock, Rainer U

2014-06-01

132

Large 0/12 GMT Differences of US Vaisala RS80 Observations  

NASA Technical Reports Server (NTRS)

The daily differences between the temperatures and heights taken at 0 GMT and 12 GMT by Vaisala RS80 rawinsondes have been calculated. The observations were obtained during selected months from 1998 - 2002 over North America, Europe and Australia. The daily differences are defined by the formula, Delta T = Delta T(sub 0) - 0.5(T(sub -12) - T(sub +12)) where AT is the 0/12 GMT difference, T(sub 0) is the 0 GMT observation and T(sub -12) and T(sub +12) are the 12 GMT observations taken just prior and after the 0 GMT synoptic time. If T(sub +12) is missing then Delta T = T(sub 0) - T(sub -12). A similar expression is used if T(sub -12) is missing. Monthly averages of the increments at each station that launch RS80 rawinsondes are then calculated. The results show positive systematic differences in the stratosphere with values as high as 5 K and 150 m at 10 hPa over the central United States. The values remain generally positive and gradually decrease as the levels descend into the upper troposphere but are still significant. In addition, the maximum at each level is just westward of 90 W at the highest levels and just eastward in the troposphere with smaller values along both coasts. In Canada as well as in Europe and Australia the differences are much smaller with no systematic patterns similar to those that exist over the contiguous United States. Time-series plots of the temperatures and heights at select stations in the United States show that the observed values taken at 0 GMT are consistently higher than those at 12 GMT. Over Canada the differences become much less apparent and some cases non-existent. The observations were obtained through National Centers for Environmental Prediction (NCEP) but were checked with data from other sources to verify that no modifications were made other than those at the stations. Since the data from outside the the United States exhibit no large systematic differences, the preliminary conclusion is that the large differences are artificial and probably originate from the post-processing software at the observing stations.

Redder, Chris; Atlas, Robert (Technical Monitor)

2002-01-01

133

Comparative transforming potential of different human papillomaviruses associated with non-melanoma skin cancer  

SciTech Connect

It is well established that high-risk human papillomaviruses (HPVs) that infect mucosal epithelia are the causative agents of cervical cancer. In contrast, the association of cutaneo-tropic HPV types with the development of non-melanoma skin cancer (NMSC) is less well defined. In this study, we have analysed the in vitro transforming potential of various cutaneous HPV types. Using oncogene cooperation assays with activated ras, we have shown that diverse cutaneous types, including 12, 14, 15, 24, 36 and 49, have significant transforming potential. Interestingly, most of this activity appears to be encoded by the E6 gene product. In contrast, the common HPV-10 exhibits no significant transforming potential in these assays. This difference may be a reflection of different patterns of cellular localization, with transforming E6s being nuclear and non-transforming being cytoplasmic. These results provide molecular support for a role of these viruses in the development of certain human malignancies.

Massimi, Paola; Thomas, Miranda [International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste (Italy); Bouvard, Veronique [Infections and Cancer Biology Group, International Agency for Research on Cancer - World Health Organization, 150 Cours Albert Thomas, 69372 Lyon (France); Ruberto, Irene [International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste (Italy); Campo, M. Saveria [Division of Pathological Sciences, Institute of Comparative Medicine, University of Glasgow, Garscube Estate, Glasgow G61 1QH (United Kingdom); Tommasino, Massimo [Infections and Cancer Biology Group, International Agency for Research on Cancer - World Health Organization, 150 Cours Albert Thomas, 69372 Lyon (France); Banks, Lawrence [International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste (Italy)], E-mail: banks@icgeb.org

2008-02-20

134

A priori implantation potential does not differ in eutopic endometrium of patients with and without endometriosis  

Microsoft Academic Search

Background: In endometriosis, angiogenesis is a crucial step for implantation of the exfoliates. A priori potential to induce angiogenesis by vascular endothelial growth factor (VEGF) expression was compared in eutopic endometrium of patients with and without endometriosis to discriminate the pivotal pathogenic step that differs in endometriosis. Methods: In an experi- mental prospective study, endometrium samples were obtained from endometriosis

D. M. Gescher; W. Siggelkow; A. Meyhoefer-Malik; E. Malik

2005-01-01

135

Active Cl ? absorption by the Chinese crab ( Eriocheir sinensis ) gill epithelium measured by transepithelial potential difference  

Microsoft Academic Search

Isolated posterior gills from Chinese crabs (Eriocheir sinensis) acclimated to tap-water were perfused and bathed with full, physiological saline (containing Na+ and Cl-). Under these conditions they developed an outside positive transepithelial potential difference (PDte). Substitution of Na+ by choline on both sides of the epithelium resulted in a substantial hyperpolarization of the PDte, while substitution of Cl- by gluconate

Horst Onken; Kai Graszynski

1989-01-01

136

Analysis of development-related gene expression in cloned bovine blastocysts with different developmental potential.  

PubMed

The high incidence of abnormalities in cloned calves is a most serious problem for bovine somatic cell nuclear transfer (NT) technology. Because there is little information on the differences in mRNA expression in cloned blastocysts with donor cells of different sex and origin, we compared development-related gene expression in two types of cloned bovine blastocysts with different potentials to develop into normal calves, a female adult cumulus cell line (high potential to develop into live calves) and a male fibroblast cell line (low potential to develop into live calves) to examine the correlation between the normality of cloned calves and blastocyst mRNA expression patterns. We analyzed 12 genes involved in apoptosis, growth factor signaling, metabolism, and DNA methylation in blastocysts originating from two types of donor cells and in vitro-fertilized blastocysts using quantitative real-time polymerase chain reaction. Expression of the pro-apoptotic Bax gene and anti-apoptotic Bcl-2 and Glut-1 genes in fibroblast-derived blastocysts was significantly higher than in cumulus cell-derived and in vitro-fertilized blastocysts. The high Bcl-2 and Glut-1 gene expression suggests that some embryonic cells with damaged DNA in fibroblast-derived blastocysts are not removed, and their descendants later manifest abnormal placenta or fetus formation. Transfer of pre-selected cloned blastocysts into recipients is required, however, to determine whether the expression pattern of these apoptosis-related genes reflects differences in the potential to develop into normal calves. PMID:16571076

Li, Xiangping; Amarnath, Dasari; Kato, Yoko; Tsunoda, Yukio

2006-01-01

137

Different Arbuscular Mycorrhizal Fungal Species Are Potential Determinants of Plant Community Structure  

Microsoft Academic Search

Almost all natural plant communities contain arbuscular mycorrhizal fungi (AMF). We hypothesized that the species composition of AMF communities could have the potential to determine plant community structure if the growth response to different AMF species or to communities of AMF species varies among plant species. To test the existence of such a differential response we conducted a pot experiment

Thomas Boller; Andres Wiemken; Ian R. Sanders

1998-01-01

138

How to Help Children with Learning Differences Reach Their Full Potential  

ERIC Educational Resources Information Center

This article is the third part of a 10-part series that explores Attention Deficit Hyperactivity Disorder (ADHD). It offers and discusses tips on how to help children with learning differences reach their full potential. These include: (1) start with good nutrition; (2) be sure your child is exercising; (3) make sure your child is getting enough…

Lavoie, Theresa

2008-01-01

139

Analysis of the Potential for a Heat Island Effect in Large Solar Vasilis Fthenakis1,2  

E-print Network

widespread installation of solar panels and found this to be small compared to benefits from the reductionAnalysis of the Potential for a Heat Island Effect in Large Solar Farms Vasilis Fthenakis1 Abstract -- Large-scale solar power plants are being built at a rapid rate, and are setting up to use

140

hal-00147705,version1-20May2007 Asymmetric potentials and motor effect: a large deviation approach  

E-print Network

hal-00147705,version1-20May2007 Asymmetric potentials and motor effect: a large deviation approach analysis of appearance of the concentrations (as Dirac masses) of the solution to a Fokker-Planck system with asymmetric potentials. This problem has been proposed as a model to describe motor proteins moving along

Paris-Sud XI, Université de

141

The Potential of Unmanned Aerial Vehicle for Large Scale Mapping of Coastal Area  

NASA Astrophysics Data System (ADS)

Many countries in the tropical region are covered with cloud for most of the time, hence, it is difficult to get clear images especially from high resolution satellite imagery. Aerial photogrammetry can be used but most of the time the cloud problem still exists. Today, this problem could be solved using a system known as unmanned aerial vehicle (UAV) where the aerial images can be acquired at low altitude and the system can fly under the cloud. The UAV system could be used in various applications including mapping coastal area. The UAV system is equipped with an autopilot system and automatic method known as autonomous flying that can be utilized for data acquisition. To achieve high resolution imagery, a compact digital camera of high resolution was used to acquire the aerial images at an altitude. In this study, the UAV system was employed to acquire aerial images of a coastal simulation model at low altitude. From the aerial images, photogrammetric image processing was executed to produce photogrammetric outputs such a digital elevation model (DEM), contour line and orthophoto. In this study, ground control point (GCP) and check point (CP) were established using conventional ground surveying method (i.e total station). The GCP is used for exterior orientation in photogrammetric processes and CP for accuracy assessment based on Root Mean Square Error (RMSE). From this study, it was found that the UAV system can be used for large scale mapping of coastal simulation model with accuracy at millimeter level. It is anticipated that the same system could be used for large scale mapping of real coastal area and produces good accuracy. Finally, the UAV system has great potential to be used for various applications that require accurate results or products at limited time and less man power.

Darwin, N.; Ahmad, A.; Zainon, O.

2014-02-01

142

Potential biases in the detection of planetary systems with large transit timing variations  

NASA Astrophysics Data System (ADS)

The transit timing variations (TTVs) technique provides a powerful tool to detect additional planets in transiting exoplanetary systems. In this Letter, we show how transiting planets with significant TTVs can be systematically missed, or catalogued as false positives, by current transit search algorithms, unless they are in multitransit systems. If the period of the TTVs, PTTV, is longer than the time baseline of the observations and its amplitude, ATTV, is larger than the timing precision limit of the data, transiting planet candidates are still detected, but with incorrect ephemerides. Therefore, they will be discarded during follow-up. When PTTV is shorter than the time baseline of the observations and ATTV is sufficiently large, constant period search algorithms find an average period for the system, which results in altered transit durations and depths in the folded light curves. Those candidates can get subsequently discarded as eclipsing binaries, grazing eclipses or blends. Also, for large enough ATTV values, the transits can get fully occulted by the photometric dispersion of the light curves. These detection biases could explain the observed statistical differences between the frequency of multiple systems among planets detected via other techniques and those detected via transits. We suggest that new transit search algorithms allowing for non-constant period planets should be implemented.

García-Melendo, E.; López-Morales, M.

2011-10-01

143

Large Extracellular Loop of Tetraspanin as a Potential Vaccine Candidate for Filariasis  

PubMed Central

Lymphatic filariasis affects nearly 120 million people worldwide and mass preventive chemotherapy is currently used as a strategy to control this infection. This has substantially reduced the incidence of the infection in several parts of the world. However, a prophylactic vaccine would be more effective in preventing future infections and will supplement the mass chemotherapy efforts. Unfortunately, there is no licensed vaccine available currently to prevent this infection. Molecules expressed on the surface of the parasite are potential candidates for vaccine development as they are exposed to the host immune system. In this study we show that the large extracellular loop of tetraspanin (TSP LEL), a protein expressed on the cuticle of Brugia malayi and Wuchereria bancrofti is a potential vaccine candidate. Our results showed that BmTSP LEL is expressed on the surface of B. malayi infective third stage larvae (L3) and sera from human subjects who are putatively immune to lymphatic filariasis carry high titer of IgG1 and IgG3 antibodies against BmTSP LEL and WbTSP LEL. We also showed that these antibodies in the sera of human subjects can participate in the killing of B. malayi L3 in an antibody dependent cell-mediated cytotoxicity mechanism. Vaccination trials in mice showed that close to 64% protection were achieved against challenge infections with B. malayi L3. Immunized animals showed high titer of anti-WbTSP LEL IgG1, IgG2a and IgG2b antibodies in the sera and IFN-? secreting cells in the spleen. Onchocerca volvulus another filarial parasite also expresses TSP LEL. Cross-reactivity studies showed that IgG1 antibody in the sera of endemic normal subjects, recognize OvTSP LEL. Similarly, anti-OvTSP LEL antibodies in the sera of subjects who are immune to O. volvulus were also shown to cross-react with rWbTSP LEL and rBmTSP LEL. These findings thus suggested that rTSP LEL can be developed as a potential vaccine candidate against multiple filarial infections. PMID:24146990

Dakshinamoorthy, Gajalakshmi; Munirathinam, Gnanasekar; Stoicescu, Kristen; Reddy, Maryada Venkatarami; Kalyanasundaram, Ramaswamy

2013-01-01

144

COMMUNALITIES AND DIFFERENCES IN FEAR POTENTIATION BETWEEN CARDIAC DEFENSE AND EYE-BLINK STARTLE  

PubMed Central

This study examines similarities and differences in fear potentiation between two protective reflexes: cardiac defense and eye-blink startle. Women reporting intense fear of animals but low fear of blood or intense fear of blood but low fear of animals viewed pictures depicting blood or the feared animal for 6 s in 2 separate trials in counterbalanced order. An intense burst of white noise, able to elicit both a cardiac defense response and a reflexive startle blink, was presented 3.5 s after picture onset. Both cardiac and blink responses were potentiated when highly fearful individuals viewed fearful pictures. However, differences appeared concerning picture order. This pattern of results indicates communalities and differences among protective reflexes that are relevant for understanding the dynamics of emotional reflex modulation. PMID:19572906

Sánchez, María B.; Guerra, Pedro; Muñoz, Miguel A.; Mata, José Luís; Bradley, Margaret M.; Lang, Peter J.; Vila, Jaime

2009-01-01

145

Large differences in land use emission quantifications implied by definition discrepancies  

NASA Astrophysics Data System (ADS)

The quantification of CO2 emissions from anthropogenic land use and land use change (eLUC) is essential to understand the drivers of the atmospheric CO2 increase and to inform climate change mitigation policy. Reported values in synthesis reports are commonly derived from different approaches (observation-driven bookkeeping and process-modelling) but recent work has emphasized that inconsistencies between methods may imply substantial differences in eLUC estimates. However, a consistent quantification is lacking and no concise modelling protocol for the separation of primary and secondary components of eLUC has been established. Here, we review the conceptual differences of eLUC quantification methods and apply an Earth System Model to demonstrate that what is claimed to represent total eLUC differs by up to ~20% when quantified from ESM vs. offline vegetation models. Under a future business-as-usual scenario, differences tend to increase further due to slowing land conversion rates and an increasing impact of altered environmental conditions on land-atmosphere fluxes. We establish how coupled Earth System Models may be applied to separate component fluxes of eLUC arising from the replacement of potential C sinks/sources and the land use feedback and show that secondary fluxes derived from offline vegetation models are conceptually and quantitatively not identical to either, nor their sum. Therefore, we argue that synthesis studies and global carbon budget accountings should resort to the "least common denominator" of different methods, following the bookkeeping approach where only primary land use emissions are quantified under the assumption of constant environmental boundary conditions.

Stocker, B. D.; Joos, F.

2015-03-01

146

Diffuse large B-cell lymphoma in the elderly: a review of potential difficulties.  

PubMed

Half of patients with diffuse large B-cell lymphoma (DLBCL) are more than 65 years old. These elderly patients frequently have other diseases, some of them severe, which may alter their ability to receive standard curative therapy. However, these associated diseases are heterogeneous and only a few contraindicate chemotherapy treatments. We reviewed all potential difficulties, such as the evaluation of comorbidities, the heterogeneous functional status of this population, and the consequences of the aging process that might be associated with treating these patients, and now propose solutions. As standard rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy may cure the majority of patients, it must always be the first proposed option. With this approach, elderly patients with DLBCL treated with a curative intent can reach a complete remission and have a similar outcome as younger patients. Reduced dose intensity must be applied for very elderly patients or those unfit for full-dose anthracycline. The critical question for a physician is why these patients cannot be treated with the standard regimen, namely R-CHOP. PMID:23339126

Sarkozy, Clémentine; Coiffier, Bertrand

2013-04-01

147

Differences between discontinuous and continuous soft-core attractive potentials: the appearance of density anomaly  

E-print Network

Soft-core attractive potentials can give rise to a phase diagram with three fluid phases at different densities (gas, low-density liquid and high-density liquid), separated by first order phase transition lines ending in critical points. Experiments show a phase diagram with these features for phosphorous and triphenyl-phosphite. Liquid-liquid phase transition could be relevant for water, silica, liquid metals, colloids and protein solutions, among others. Here we compare two potentials with short-range soft-core repulsion and narrow attraction. One of them is a squared potential that is known to have liquid-liquid phase transition, ending in a critical point, and no anomaly in density. The normal, monotonic, behavior of density for isobaric cooling is surprising if compared with molecular liquids, such as water, where a hypothetical critical point is proposed as rationale for the anomalous behavior of density. The second potential is a continuous version of the first. We show that the phase diagram associated to this new potential has, not only the liquid-liquid phase transition, but also the density anomaly. Our result, therefore, shows that the behavior in density is strongly dependent on the derivative of the potential.

Giancarlo Franzese

2007-04-17

148

Large submarine earthquakes occurred worldwide, 1 year period (June 2013 to June 2014), - contribution to the understanding of tsunamigenic potential  

NASA Astrophysics Data System (ADS)

This paper is a contribution to a better understanding of tsunamigenic potential from large submarine earthquakes. Here, we analyse the tsunamigenic potential of large earthquakes occurred worldwide with magnitudes around Mw 7.0 and greater, during a period of 1 year, from June 2013 to June 2014. The analysis involves earthquake model evaluation, tsunami numerical modelling, and sensors' records analysis in order to confirm the generation or not of a tsunami following the occurrence of an earthquake. We also investigate and discuss the sensitivity of tsunami generation to the earthquake parameters recognized to control the tsunami occurrence, including the earthquake magnitude, focal mechanism and fault rupture depth. A total of 23 events, with magnitudes ranging from Mw 6.7 to Mw 8.1 and hypocenter depths varying from 10 up to 585 km, have been analyzed in this study. Among them, 52% are thrust faults, 35% are strike-slip faults, and 13% are normal faults. Most analyzed events have been occurred in the Pacific Ocean. This study shows that about 39% of the analyzed earthquakes caused tsunamis that were recorded by different sensors with wave amplitudes varying from few centimetres to about 2 m. Some of them caused inundations of low-lying coastal areas and significant damages in harbours. On the other hand, tsunami numerical modeling shows that some of the events, considered as non-tsunamigenic, might trigger small tsunamis that were not recorded due to the absence of sensors in the near-field areas. We also find that the tsunami generation is mainly dependent of the earthquake focal mechanism and other parameters such as the earthquake hypocenter depth and the magnitude. The results of this study can help on the compilation of tsunami catalogs.

Omira, R.; Vales, D.; Marreiros, C.; Carrilho, F.

2015-03-01

149

Three different group I introns in the nuclear large subunit ribosomal DNA of the amoeboflagellate Naegleria.  

PubMed Central

We have amplified the large subunit ribosomal DNA (LSUrDNA) of the 12 described Naegleria spp. and of 34 other Naegleria lineages that might be distinct species. Two strains yielded a product that is longer than 3 kb, which is the length of the LSUrDNA of all described Naegleria spp. Sequencing data revealed that the insert in one of these strains is a group I intron without an open reading frame (ORF), while the other strain contains two different group I introns, of which the second intron has an ORF of 175 amino acids. In the latter ORF there is a conserved His-Cys box, as in the homing endonucleases present in group I introns in the small subunit ribosomal DNA (SSUrDNA) of Naegleria spp. Although the group I introns in the LSUrDNA differ in sequence, they are more related to each other than they are to the group I introns in the SSUrDNA of Naegleria spp. The three group I introns in the LSUrDNA in Naegleria are at different locations and are probably acquired by horizontal transfer, contrary to the SSUrDNA group I introns in this genus which are of ancestral origin and are transmitted vertically. PMID:9421500

De Jonckheere, J F; Brown, S

1998-01-01

150

Evolutionary potential of a large marine vertebrate: quantitative genetic parameters in a wild population.  

PubMed

Estimating quantitative genetic parameters ideally takes place in natural populations, but relatively few studies have overcome the inherent logistical difficulties. For this reason, no estimates currently exist for the genetic basis of life-history traits in natural populations of large marine vertebrates. And yet such estimates are likely to be important given the exposure of this taxon to changing selection pressures, and the relevance of life-history traits to population productivity. We report such estimates from a long-term (1995-2007) study of lemon sharks (Negaprion brevirostris) conducted at Bimini, Bahamas. We obtained these estimates by genetically reconstructing a population pedigree (117 dams, 487 sires, and 1351 offspring) and then using an "animal model" approach to estimate quantitative genetic parameters. We find significant additive genetic (co)variance, and hence moderate heritability, for juvenile length and mass. We also find substantial maternal effects for these traits at age-0, but not age-1, confirming that genotype-phenotype interactions between mother and offspring are strongest at birth; although these effects could not be parsed into their genetic and nongenetic components. Our results suggest that human-imposed selection pressures (e.g., size-selective harvesting) might impose noteworthy evolutionary change even in large marine vertebrates. We therefore use our findings to explain how maternal effects may sometimes promote maladaptive juvenile traits, and how lemon sharks at different nursery sites may show "constrained local adaptation." We also show how single-generation pedigrees, and even simple marker-based regression methods, can provide accurate estimates of quantitative genetic parameters in at least some natural systems. PMID:19236474

Dibattista, Joseph D; Feldheim, Kevin A; Garant, Dany; Gruber, Samuel H; Hendry, Andrew P

2009-04-01

151

Antioxidant, total phenolic contents and antinociceptive potential of Teucrium stocksianum methanolic extract in different animal models  

PubMed Central

Background Oxidative stress and analgesia are connected with different pathological conditions. The drug candidates from synthetic sources are associated with various side effects; therefore, researchers are giving priority to find novel, effective and safe phytomedicines. Teucrium species possesses antioxidant, analgesic, anti-inflammatory and hepatoprotective activities. The essential oils of Teucrium stocksianum have shown strong antinociceptive potential. Our current study is designed to embark total phenolic content (TPC), antioxidant and antinociceptive potential of the methanolic extract of Teucrium stocksianum (METS). Method Phytochemical composition was determined by using standard methods. Free radical scavenging potential and TPC of METS were assessed by using 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) and Folin-Ciocalteu Reagent (FCR) respectively. Antinociceptive potential was determined by acetic acid induced abdominal writhing, formalin induced paw licking and tail immersion tests. Different test dose 50, 100 and 150 mg/kg body weight of METS were administered intra peritonealy (i.p) to various groups of mice for the evaluation of analgesic potential. Results Phytochemical screening confirmed the presence of flavonoids, tannins, saponins, anthraquinone, steroid, phlobatannin, terpenoid, glycoside and reducing sugars. METS was found safe at a dose of 1000 mg/kg body weight. A concentration dependent free radical scavenging effect was observed with methanolic aerial parts extract of Teucrium stocksianum (MAPETS) and methanolic roots extracts of Teucrium stocksianum (MRETS). MAPETS and MRETS have shown highest antioxidant activity 91.72% and 86.19% respectively at 100 ?g/ml. MAPETS was found more rich (115.32 mg of GAE/g of dry material) in TPC as compared to MAPETS (105.41 mg of GAE/g). METS demonstrated a dose dependent antinociceptive potential in different pain models, like in acetic acid, formalin and tail immersion showing 83.103%, 80.872% and 67.58% at a dose of 150 mg/kg, similar to acetylsalicylic acid (74.79%, 82.87%, 100 mg/kg) and TramadolR (74%, 30 mg/kg) respectively. Conclusion Strong antioxidant potential and high TPCs are residing in the methanolic extract of T. stocksianum. METS showed analgesic potential in all models of nociception implying that both peripheral and central pathways of analgesia are involved. This might be due to the presence of various classes of phytochemicals in the plant extract. PMID:24893601

2014-01-01

152

Analysis of Potential for Titanium Liner Buckling after Proof in a Large Kevlar/Epoxy COPV  

NASA Technical Reports Server (NTRS)

We analyze the potential for liner buckling in a 40-in Kevlar49/epoxy overwrapped spherical pressure vessel (COPV) due to long, local depressions or valleys in the titanium liner, which appeared after proof testing (autofrettage). We begin by presenting the geometric characteristics of approximately 20 mil (0.02 in.) deep depressions measured by laser profilometry in several vessels. While such depths were more typical, depths of more than 40 mils (0.02 in.) were seen near the equator in one particular vessel. Such depressions are largely the result of overlap of the edges of overwrap bands (with rectangular cross-section prepreg tows) from the first or second wrap patterns particularly where they start and end. We then discuss the physical mechanisms of formation of the depressions during the autofrettage process in terms of uneven void compaction in the overwrap around the tow overlap lines and the resulting 10-fold increase in through-thickness stiffness of the overwrap. We consider the effects of liner plastic yielding mechanisms in the liner on residual bending moments and interface pressures with the overwrap both at the peak proof pressure (approx.6500 psi) and when reducing the pressure to 0 psi. During depressurization the Bauschinger phenomenon becomes very important whereby extensive yielding in tension reduces the magnitude of the yield threshold in compression by 30 to 40%, compared to the virgin annealed state of the liner titanium. In the absence of a depression, the liner is elastically stable in compression even at liner overwrap interface pressures nominally 6 times the approx. 1000 psi interface pressure that exists at 0 psi. Using a model based on a plate-on-an-elastic-foundation, we develop an extensive analysis of the possible destabilizing effects of a frozen-in valley. The analysis treats the modifying effects of the residual bending moments and interface pressures remaining after the proof hold as well as the Bauschinger effect on the compressive yield threshold. The key result is that depression depths of up to 40 mils can be tolerated, but above 40 mils, the Bauschinger effect drives destabilization, and buckling becomes increasingly likely depending on the details of depression formation during autofrettage. It is almost certain that destabilization and buckling will occur for depression depths beyond 55 mils. The main equations and formulas for treating the various phases of depression development and potential buckling, are only briefly outlined in the paper, but are available from the authors.

Phoenix, S. Leigh; Kezirian, Michael T.

2009-01-01

153

Large eddy simulation of a muffler with the high-order spectral difference method  

E-print Network

The combination of the high-order accurate spectral difference discretization on unstructured grids with subgrid-scale modelling is investigated for large eddy simulation of a muffler at Re = 4.64 10^4 and low Mach number. The subgrid-scale stress tensor is modelled by the wall-adapting local eddy-viscosity model with a cut-off length which is a decreasing function of the order of accuracy of the scheme. Numerical results indicate that although the high-order solver without subgrid-scale modelling is already able to capture well the features of the flow, the coupling with the wall-adapting local eddy-viscosity model improves the quality of the solution.

Parsani, Matteo; Lacor, Chris

2013-01-01

154

Large eddy simulation of a muffler with the high-order spectral difference method  

E-print Network

The combination of the high-order accurate spectral difference discretization on unstructured grids with subgrid-scale modelling is investigated for large eddy simulation of a muffler at Re = 4.64 10^4 and low Mach number. The subgrid-scale stress tensor is modelled by the wall-adapting local eddy-viscosity model with a cut-off length which is a decreasing function of the order of accuracy of the scheme. Numerical results indicate that although the high-order solver without subgrid-scale modelling is already able to capture well the features of the flow, the coupling with the wall-adapting local eddy-viscosity model improves the quality of the solution.

Matteo Parsani; Michael Bilka; Chris Lacor

2013-05-29

155

Large differences in catch per unit of effort between two minnow trap models  

PubMed Central

Background Little is known about variation in catch per unit of effort (CPUE) in stickleback fisheries, or the factors explaining this variation. We investigated how nine-spined stickleback (Pungitius pungitius) CPUE was influenced by trap model by comparing the CPUEs of two very similar minnow trap models fished side-by-side in a paired experimental design. Results The galvanized trap type (mean CPUE?=?1.31 fish h–1) out-fished the black trap type (mean CPUE?=?0.20 fish h–1) consistently, and yielded on average 81% more fish. Conclusions The results demonstrate that small differences in trap appearance can have large impacts on CPUE. This has implications for studies designed to investigate abundance and occurrence of fish using minnow traps. PMID:23590839

2013-01-01

156

Damage mechanism at different transpassive potentials of solution-annealed 316 and 316l stainless steels  

NASA Astrophysics Data System (ADS)

Electrochemical impedance spectroscopy (EIS), anodic polarization and scanning electron microscopy techniques were used to investigate the damage mechanism in the transpassive potential region of AISI 316 and AISI 316L solution-annealed stainless steels (SS) with different degrees of sensitization. Depending on the DC potential applied during EIS tests, the AC responses in the transpassive region included three different regions: the first one associated with anodic dissolution of the passive layer, the second one contributed to the dissolution at the area near grain boundaries, and the last one attributed to pitting corrosion. In addition, the fitting results to experimental data showed that as the DC bias during the EIS test increases the charge transfer resistance ( R ct) decreases. Moreover, the R ct values decreased as the sensitization temperature increases but the AISI 316L SS samples exhibited a higher resistance to intergranular corrosion than 316 SS samples.

Morshed Behbahani, K.; Pakshir, M.; Abbasi, Z.; Najafisayar, P.

2015-01-01

157

Coarse-grained modeling of large RNA molecules with knowledge-based potentials and structural filters.  

PubMed

Understanding the function of complex RNA molecules depends critically on understanding their structure. However, creating three-dimensional (3D) structural models of RNA remains a significant challenge. We present a protocol (the nucleic acid simulation tool [NAST]) for RNA modeling that uses an RNA-specific knowledge-based potential in a coarse-grained molecular dynamics engine to generate plausible 3D structures. We demonstrate NAST's capabilities by using only secondary structure and tertiary contact predictions to generate, cluster, and rank structures. Representative structures in the best ranking clusters averaged 8.0 +/- 0.3 A and 16.3 +/- 1.0 A RMSD for the yeast phenylalanine tRNA and the P4-P6 domain of the Tetrahymena thermophila group I intron, respectively. The coarse-grained resolution allows us to model large molecules such as the 158-residue P4-P6 or the 388-residue T. thermophila group I intron. One advantage of NAST is the ability to rank clusters of structurally similar decoys based on their compatibility with experimental data. We successfully used ideal small-angle X-ray scattering data and both ideal and experimental solvent accessibility data to select the best cluster of structures for both tRNA and P4-P6. Finally, we used NAST to build in missing loops in the crystal structures of the Azoarcus and Twort ribozymes, and to incorporate crystallographic data into the Michel-Westhof model of the T. thermophila group I intron, creating an integrated model of the entire molecule. Our software package is freely available at https://simtk.org/home/nast. PMID:19144906

Jonikas, Magdalena A; Radmer, Randall J; Laederach, Alain; Das, Rhiju; Pearlman, Samuel; Herschlag, Daniel; Altman, Russ B

2009-02-01

158

Generalized energy and potential enstrophy conserving finite difference schemes for the shallow water equations  

NASA Technical Reports Server (NTRS)

The conditions under which finite difference schemes for the shallow water equations can conserve both total energy and potential enstrophy are considered. A method of deriving such schemes using operator formalism is developed. Several such schemes are derived for the A-, B- and C-grids. The derived schemes include second-order schemes and pseudo-fourth-order schemes. The simplest B-grid pseudo-fourth-order schemes are presented.

Abramopoulos, Frank

1988-01-01

159

Potentials and constraints of different types of soil moisture observations for flood simulations in headwater catchments  

Microsoft Academic Search

Flood generation in mountainous headwater catchments is governed by rainfall intensities, by the spatial distribution of rainfall\\u000a and by the state of the catchment prior to the rainfall, e.g. by the spatial pattern of the soil moisture, groundwater conditions\\u000a and possibly snow. The work presented here explores the limits and potentials of measuring soil moisture with different methods\\u000a and in

Axel Bronstert; Benjamin Creutzfeldt; Thomas Graeff; Irena Hajnsek; Maik Heistermann; Sibylle Itzerott; Thomas Jagdhuber; David Kneis; Erika Lück; Dominik Reusser; Erwin Zehe

160

When species' ranges meet: assessing differences in habitat selection between sympatric large carnivores.  

PubMed

Differentiation in habitat selection among sympatric species may depend on niche partitioning, species interactions, selection mechanisms and scales considered. In a mountainous area in Sweden, we explored hierarchical habitat selection in Global Positioning System-collared individuals of two sympatric large carnivore species; an obligate predator, the Eurasian lynx (Lynx lynx), and a generalist predator and scavenger, the wolverine (Gulo gulo). Although the species' fundamental niches differ widely, their ranges overlap in this area where they share a prey base and main cause of mortality. Both lynx and wolverines selected for steep and rugged terrain in mountainous birch forest and in heaths independent of scale and available habitats. However, the selection of lynx for their preferred habitats was stronger when they were forming home ranges and they selected the same habitats within their home ranges independent of home range composition. Wolverines displayed a greater variability when selecting home ranges and habitat selection also varied with home range composition. Both species selected for habitats that promote survival through limited encounters with humans, but which also are rich in prey, and selection for these habitats was accordingly stronger in winter when human activity was high and prey density was low. We suggest that the observed differences between the species result primarily from different foraging strategies, but may also depend on differences in ranging and resting behaviour, home range size, and relative density of each species. Our results support the prediction that sympatric carnivores with otherwise diverging niches can select for the same resources when sharing main sources of food and mortality. PMID:23242426

Rauset, Geir Rune; Mattisson, Jenny; Andrén, Henrik; Chapron, Guillaume; Persson, Jens

2013-07-01

161

Parametric Evaluation of Large-Scale High-Temperature Electrolysis Hydrogen Production Using Different Advanced Nuclear Reactor Heat Sources  

SciTech Connect

High Temperature Electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800 °C to 950 °C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an Intermediate Heat Exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed to evaluate the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered.

Edwin A. Harvego; Michael G. McKellar; James E. O'Brien; J. Stephen Herring

2009-09-01

162

Tetraploid and hexaploid wheat varieties reveal large differences in expression of alpha-gliadins from homoeologous Gli-2 loci  

PubMed Central

Background ?-gliadins form a multigene protein family encoded by multiple ?-gliadin (Gli-2) genes at three genomic loci, Gli-A2, Gli-B2 and Gli-D2, respectively located on the homoeologous wheat chromosomes 6AS, 6BS, and 6DS. These proteins contain a number of important celiac disease (CD)-immunogenic domains. The ?-gliadins expressed from the Gli-B2 locus harbour fewer conserved CD-epitopes than those from Gli-A2, whereas the Gli-D2 gliadins have the highest CD-immunogenic potential. In order to detect differences in the highly CD-immunogenic ?-gliadin fraction we determined the relative expression level from the homoeologous Gli-2 loci in various tetraploid and hexaploid wheat genotypes by using a quantitative pyrosequencing method and by analyzing expressed sequence tag (EST) sequences. Results We detected large differences in relative expression levels of ?-gliadin genes from the three homoeologous loci among wheat genotypes, both as relative numbers of expressed sequence tag (EST) sequences from specific varieties and when using a quantitative pyrosequencing assay specific for Gli-A2 genes. The relative Gli-A2 expression level in a tetraploid durum wheat cultivar ('Probstdorfer Pandur') was 41%. In genotypes derived from landraces, the Gli-A2 frequency varied between 12% and 58%. In some advanced hexaploid bread wheat cultivars the genes from locus Gli-B2 were hardly expressed (e.g., less than 5% in 'Lavett') but in others they made up more than 40% (e.g., in 'Baldus'). Conclusion Here, we have shown that large differences exist in relative expression levels of ?-gliadins from the homoeologous Gli-2 loci among wheat genotypes. Since the homoelogous genes differ in the amount of conserved CD-epitopes, screening for differential expression from the homoeologous Gli-2 loci can be employed for the pre-selection of wheat varieties in the search for varieties with very low CD-immunogenic potential. Pyrosequencing is a method that can be employed for such a 'gene family-specific quantitative transcriptome profiling'. PMID:19171027

Salentijn, Elma MJ; Goryunova, Svetlana V; Bas, Noor; van der Meer, Ingrid M; van den Broeck, Hetty C; Bastien, Thomas; Gilissen, Luud JWJ; Smulders, Marinus JM

2009-01-01

163

Performance assessment of different constraining potentials in computational structure prediction for disulfide-bridged proteins.  

PubMed

The presence of disulfide bonds in proteins has very important implications on the three-dimensional structure and folding of proteins. An adequate treatment of disulfide bonds in de-novo protein simulations is therefore very important. Here we present a computational study of a set of small disulfide-bridged proteins using an all-atom stochastic search approach and including various constraining potentials to describe the disulfide bonds. The proposed potentials can easily be implemented in any code based on all-atom force fields and employed in simulations to achieve an improved prediction of protein structure. Exploring different potential parameters and comparing the structures to those from unconstrained simulations and to experimental structures by means of a scoring function we demonstrate that the inclusion of constraining potentials improves the quality of final structures significantly. For some proteins (1KVG and 1PG1) the native conformation is visited only in simulations in presence of constraints. Overall, we found that the Morse potential has optimal performance, in particular for the ?-sheet proteins. PMID:21864792

Kondov, Ivan; Verma, Abhinav; Wenzel, Wolfgang

2011-08-10

164

Interspecies differences in bone composition, density, and quality: potential implications for in vivo bone research.  

PubMed

This study compares bone composition, density, and quality in bone samples derived from seven vertebrates that are commonly used in bone research: human, dog, pig, cow, sheep, chicken, and rat. Cortical femoral bone samples were analyzed for their content of ash, collagen, extractable proteins, and insulin-like growth factor-I. These parameters were also measured in bone powder fractions that were obtained after separation of bone particles according to their density. Large interspecies differences were observed in all analyses. Of all species included in the biochemical analyses, rat bone was most different, whereas canine bone best resembled human bone. In addition, bone density and mechanical testing analyses were performed on cylindrical trabecular bone cores. Both analyses demonstrated large interspecies variations. The lowest bone density and fracture stress values were found in the human samples; porcine and canine bone best resembled these samples. The relative contribution of bone density to bone mechanical competence was largely species-dependent. Together, the data reported here suggest that interspecies differences are likely to be found in other clinical and experimental bone parameters and should therefore be considered when choosing an appropriate animal model for bone research. PMID:9449639

Aerssens, J; Boonen, S; Lowet, G; Dequeker, J

1998-02-01

165

Identification of flubendazole as potential anti-neuroblastoma compound in a large cell line screen  

PubMed Central

Flubendazole was shown to exert anti-leukaemia and anti-myeloma activity through inhibition of microtubule function. Here, flubendazole was tested for its effects on the viability of in total 461 cancer cell lines. Neuroblastoma was identified as highly flubendazole-sensitive cancer entity in a screen of 321 cell lines from 26 cancer entities. Flubendazole also reduced the viability of five primary neuroblastoma samples in nanomolar concentrations thought to be achievable in humans and inhibited vessel formation and neuroblastoma tumour growth in the chick chorioallantoic membrane assay. Resistance acquisition is a major problem in high-risk neuroblastoma. 119 cell lines from a panel of 140 neuroblastoma cell lines with acquired resistance to various anti-cancer drugs were sensitive to flubendazole in nanomolar concentrations. Tubulin-binding agent-resistant cell lines displayed the highest flubendazole IC50 and IC90 values but differences between drug classes did not reach statistical significance. Flubendazole induced p53-mediated apoptosis. The siRNA-mediated depletion of the p53 targets p21, BAX, or PUMA reduced the neuroblastoma cell sensitivity to flubendazole with PUMA depletion resulting in the most pronounced effects. The MDM2 inhibitor and p53 activator nutlin-3 increased flubendazole efficacy while RNAi-mediated p53-depletion reduced its activity. In conclusion, flubendazole represents a potential treatment option for neuroblastoma including therapy-refractory cells. PMID:25644037

Michaelis, Martin; Agha, Bishr; Rothweiler, Florian; Löschmann, Nadine; Voges, Yvonne; Mittelbronn, Michel; Starzetz, Tatjana; Harter, Patrick N.; Abhari, Behnaz A.; Fulda, Simone; Westermann, Frank; Riecken, Kristoffer; Spek, Silvia; Langer, Klaus; Wiese, Michael; Dirks, Wilhelm G.; Zehner, Richard; Cinatl, Jaroslav; Wass, Mark N.; Cinatl, Jindrich

2015-01-01

166

Identification of flubendazole as potential anti-neuroblastoma compound in a large cell line screen.  

PubMed

Flubendazole was shown to exert anti-leukaemia and anti-myeloma activity through inhibition of microtubule function. Here, flubendazole was tested for its effects on the viability of in total 461 cancer cell lines. Neuroblastoma was identified as highly flubendazole-sensitive cancer entity in a screen of 321 cell lines from 26 cancer entities. Flubendazole also reduced the viability of five primary neuroblastoma samples in nanomolar concentrations thought to be achievable in humans and inhibited vessel formation and neuroblastoma tumour growth in the chick chorioallantoic membrane assay. Resistance acquisition is a major problem in high-risk neuroblastoma. 119 cell lines from a panel of 140 neuroblastoma cell lines with acquired resistance to various anti-cancer drugs were sensitive to flubendazole in nanomolar concentrations. Tubulin-binding agent-resistant cell lines displayed the highest flubendazole IC50 and IC90 values but differences between drug classes did not reach statistical significance. Flubendazole induced p53-mediated apoptosis. The siRNA-mediated depletion of the p53 targets p21, BAX, or PUMA reduced the neuroblastoma cell sensitivity to flubendazole with PUMA depletion resulting in the most pronounced effects. The MDM2 inhibitor and p53 activator nutlin-3 increased flubendazole efficacy while RNAi-mediated p53-depletion reduced its activity. In conclusion, flubendazole represents a potential treatment option for neuroblastoma including therapy-refractory cells. PMID:25644037

Michaelis, Martin; Agha, Bishr; Rothweiler, Florian; Löschmann, Nadine; Voges, Yvonne; Mittelbronn, Michel; Starzetz, Tatjana; Harter, Patrick N; Abhari, Behnaz A; Fulda, Simone; Westermann, Frank; Riecken, Kristoffer; Spek, Silvia; Langer, Klaus; Wiese, Michael; Dirks, Wilhelm G; Zehner, Richard; Cinatl, Jaroslav; Wass, Mark N; Cinatl, Jindrich

2015-01-01

167

Implicit Large Eddy Simulation of Flow over a Corrugated Dragonfly Wing Using High-Order Spectral Difference Method  

NASA Astrophysics Data System (ADS)

Implicit large eddy simulations of flow over a corrugated dragonfly wing at a Reynolds number of 34,000 at high angles of attack have been investigated with a high-order unstructured spectral difference Navier-Stokes solver. The computational results are compared with a recent experimental study by Hu et al. Both 2D and 3D simulations are carried out to assess how realistic and reliable the 2D simulations are in comparison with 3D simulations. At the angle of attack of 16 degrees, the 2D simulation failed to predict the stall observed in the experiment, while the 3D simulation correctly predicted the stall. In addition, the 3D simulation predicted a mean lift coefficient within 5% of the experimental data. We plan to compute at least another angle of attack and compare with the experimental data. The numerical simulations demonstrated the potential of the high-order SD method in large eddy simulation of physically complex problems.

Wang, Z. J.

2009-11-01

168

Differences in PAR-2 activating potential by king crab (Paralithodes camtschaticus), salmon (Salmo salar), and bovine (Bos taurus) trypsin  

PubMed Central

Background Salmon trypsin is shown to increase secretion of the pro-inflammatory cytokine interleukin (IL)-8 from human airway epithelial cells through activation of PAR-2. Secretion of IL-8 induced by king crab trypsin is observed in a different concentration range compared to salmon trypsin, and seems to be only partially related to PAR-2 activation. This report aim to identify differences in the molecular structure of king crab trypsin (Paralithodes camtschaticus) compared to salmon (Salmo salar) and bovine trypsin (Bos taurus) that might influence the ability to activate protease-activated receptor-2 (PAR-2). Results During purification king crab trypsin displayed stronger binding capacity to the anionic column used in fast protein liquid chromatography compared to fish trypsins, and was identified as a slightly bigger molecule. Measurements of enzymatic activity yielded no obvious differences between the trypsins tested. Molecular modelling showed that king crab trypsin has a large area with strong negative electrostatic potential compared to the smaller negative areas in bovine and salmon trypsins. Bovine and salmon trypsins also displayed areas with strong positive electrostatic potential, a feature lacking in the king crab trypsin. Furthermore we have identified 3 divergent positions (Asp196, Arg244, and Tyr247) located near the substrate binding pocket of king crab trypsin that might affect the binding and cleavage of PAR-2. Conclusion These preliminary results indicate that electrostatic interactions could be of importance in binding, cleavage and subsequent activation of PAR-2. PMID:23870109

2013-01-01

169

Extranodal and nodal diffuse large B cell lymphoma of the head and neck: two different entities?  

PubMed

This study analyzes patients with head and neck diffuse large B cell lymphoma (HN-DLBCL), focusing on the differences in the biological characteristics and prognosis of lymphomas of nodal and extranodal origin. We have included 72 patients with stage I-II HN-DLBCL who had updated survival information and diagnostic paraffin-embedded tissue blocks available for review. Non-germinal center phenotype (73.7 vs. 32.4 %, P?=?0.001) and high level of Bcl-2 expression (78.9 vs. 52.9 %, P?=?0.025) were more frequent in nodal than extranodal lymphomas. Univariate analyses indicated that bulky disease, Ann Arbor stage II, high level of Ki-67 expression, and primary nodal disease had adverse effects on complete remission (CR), but these effects were confirmed in a multivariate analysis for primary nodal disease and bulky disease. Patients with primary extranodal lymphoma also had better overall survival (OS) (87.7 vs. 72.5 %, P?=?0.04) and event-free survival (EFS) (84 vs. 58.5 %, P?=?0.046) than patients with nodal disease, although in the multivariate analysis, only Ann Arbor stage II continued to predict worse OS and EFS, whereas bulky disease was an independent prognostic factor only for EFS. We found significant differences in the biological characteristics and prognosis between primary nodal and extranodal HN-DLBCL. PMID:25537456

Sánchez, L A Guardado; Redondo, A M; Muñez, O Blanco; Sebastián, E; Alcoceba, M; González, M; Martín, A; Caballero, D

2015-04-01

170

Potential Mechanisms for Racial and Ethnic Differences in Antimüllerian Hormone and Ovarian Reserve  

PubMed Central

Accumulating evidence suggests that reproductive potential and function may be different across racial and ethnic groups. Racial differences have been demonstrated in pubertal timing, infertility, outcomes after assisted reproductive technology (ART) treatment, and reproductive aging. Recently, racial differences have also been described in serum antimüllerian hormone (AMH), a sensitive biomarker of ovarian reserve, supporting the notion that ovarian reserve differs between racial/ethnic groups. The existence of such racial/ethnic differences in ovarian reserve, as reflected by AMH, may have important clinical implications for reproductive endocrinologists. However, the mechanisms which may underlie such racial differences in ovarian reserve are unclear. Various genetic factors and environmental factors such as obesity, smoking, and vitamin D deficiency which have been shown to correlate with serum AMH levels and also display significant racial/ethnic variations are discussed in this review. Improving our understanding of racial differences in ovarian reserve and their underlying causes may be essential for infertility treatment in minority women and lead to better reproductive planning, improved treatment outcomes, and timely interventions which may prolong reproductive lifespan in these women. PMID:24348557

Seifer, David B.

2013-01-01

171

Potential for large-scale submarine slope failure and tsunami generation along the US mid-Atalantic coast  

NSDL National Science Digital Library

This paper from the journal GEOLOGY, "Potential for large-scale submarine slope failure and tsunami generation along the US mid-Atlantic coast," by Neal W. Driscoll, Jeffrey K. Weissel, and John A. Goff, has made headlines in recent weeks for its claim that the outer continental shelf off the coasts of Virginia and North Carolina "might be in the initial stages of large-scale slope failure." Such failure would likely produce a significant Tsunami effect along the eastern coast.

Driscoll, Neal W.

2000-01-01

172

Structure of different within-plate magmatic system of large igneous provinces  

NASA Astrophysics Data System (ADS)

It is generally accepted that formation of continental large igneous provinces (LIPs) is linked with ascending of mantle superplumes. However, it is not clear yet why and how magmatic systems appeared and functionated. It is known that LIPs are formed by numerous magmatic centers, which imply existence of individual magmatic systems beneath them. Such a situation can be explained by presence of protuberances (local plumes) on the surface of extended superplume heads, where processes of adiabatic melting occurred give rise to formation of magmatic systems. Newly-formed melts on their way to the surface pass through complicate system of conduits and transitional magma chambers, where they were undergone by different processes of crystallizing differentiation, mixing, assimilation of wall-rocks, etc. According to data available, three major levels of transitional magmatic chambers, linked by systems of feeder conduits (dikes), occurred within the crust. Each of them is responsible for transformation of a primary melt in different extent: The lowest level with the largest chambers, located along boundary between upper margin of the plume head and incumbent rigid lithosphere; they are responsible for the underplating phenomenon. Processes of contamination mantle-derived magmas by crustal material can play essential role here, especially in the late Archean and early Paleoproterozoic when they led to appearance of specific mantle-crustal magmas of siliceous high-Mg series (SHMS), which formed large igneous provinces with numerous mafic-iltramafic layered intrusions (Sharkov, Bogina, 2006). It suggests that formation of this series was linked with "floating up" of chambers (batches) of high-temperature ultramafic magmas through the upper part of lithospheric mantle and mafic lower crust by zone refinement mechanism, i.e. by melting material of the chamber's roof and crystallization at their bottoms. As a result, the primary melt gradually enriched in crustal material; portions of such series of melts periodically arrived into hardening transitional magma chambers of the middle level. Very likely that such structure of magmatic systems was typical also for the earliest Moon's magnesian suite magmatism, where such type layered mafic-ultramafic intrusions was found (Snyder et al., 1995). (2) Processes at the middle level are easy to understand on example of large layered mafic-ultramafic intrusions which are represent hardened transition magma chambers. Crystallizing differentiation as well as mixing of periodically arrived into hardening intrusive chambers fresh portions of magmas with evolved melts in it occurred here. Specific type of transitional magma chambers are represented by huge bimodal anorthosite-rapakivi granite complexes (ARGCs), typical for the Mesoproterozoic. They were formed under conditions of unusually thick (70-80 km at the moment) continental crust. Geological, geochemical and isotope data evidence that melting in the mantle and silicic crust occurred here simultaneously above local mantle plumes. It suggests that melting of the crust's material occurred above sill-like intrusions of basaltic melt which were led to appearance of large magma chambers, where mafic and sialic melts coexisted; such chambers represented now as ARGCs. By contrast to continental crust, under conditions of thin oceanic crust processes at the low and middle levels of magmatic systems are united, and layered mafic-ultramafic intrusions occurred directly between the ultramafic mantle and rocks of the upper crust, play role of the lower oceanic crust, how it is easily to observe on example of ophiolite associations. (3) The shallow level - subvolcanic chambers (usually sills), from which melts arrive to the surface, forming individual volcanoes and lava plateaus. Processes of contamination of wall rocks and crystallizing differentiation are very limited here due to small size of bodies and, accordingly, low heat keeping and quickly hardening. So, primary magmatic melt can reach the surface very rare; as a rule, it had undergone

Sharkov, E.

2009-04-01

173

Possible experiments to distinguish between different methods of treating the Pauli principle in nuclear potential models  

SciTech Connect

The finite Pauli repulsion model of Walliser and Nakaichi-Maeda and the orthogonality condition model are two microscopically motivated potential models for the description of nuclear collisions which, however, differ from each other in the way they incorporate antisymmetrization effects into the nucleus-nucleus interaction. We have used ..cap alpha..+..cap alpha.. scattering at low energies as a tool to distinguish between the two different treatments of the Pauli principle. Both models are consistent with the presently available on-shell (elastic) and off-shell (bremsstrahlung) data. We suggest further measurements of ..cap alpha..+..cap alpha.. bremsstrahlung including the coplanar laboratory differential cross section in Harvard geometry at ..cap alpha..-particle angles of around 27/sup 0/ and the ..gamma..-decay width of the 4/sup +/ resonance at E/sub c.m./ = 11.4 MeV, because in both cases the two models make significantly different predictions.

Krolle, D.; Assenbaum, H.J.; Funck, C.; Langanke, K.

1987-05-01

174

Environmental assessment of two different crop systems in terms of biomethane potential production.  

PubMed

The interest in renewable energy sources has gained great importance in Europe due to the need to reduce fossil energy consumption and greenhouse gas emissions, as required by the Renewable Energy Directive (RED) of the European Parliament. The production of energy from energy crops appears to be consistent with RED. The environmental impact related to this kind of energy primarily originates from crop cultivation. This research aimed to evaluate the environmental impact of different crop systems for biomass production: single and double crop. The environmental performances of maize and maize plus wheat were assessed from a life cycle perspective. Two alternative scenarios considering different yields, crop management, and climatic conditions, were also addressed. One normal cubic metre of potential methane was chosen as a functional unit. Methane potential production data were obtained through lab experimental tests. For both of the crop systems, the factors that have the greatest influence on the overall environmental burden are: fertilizer emissions, diesel fuel emissions, diesel fuel production, and pesticide production. Notwithstanding the greater level of methane potential production, the double crop system appears to have the worse environmental performance with respect to its single crop counterpart. This result is due to the bigger quantity of inputs needed for the double crop system. Therefore, the greater amount of biomass (silage) obtained through the double crop system is less than proportional to the environmental burden that results from the bigger quantity of inputs requested for double crop. PMID:23994820

Bacenetti, Jacopo; Fusi, Alessandra; Negri, Marco; Guidetti, Riccardo; Fiala, Marco

2014-01-01

175

Heavy Quark Potential at Finite Temperature in a Dual Gravity Closer to Large N QCD  

E-print Network

In gauge-gravity duality, the heavy quark potential at finite temperature is usually calculated with the pure AdS background, which does not capture the renormalization group (RG) running in the gauge theory part. In addition, the potential does not contain any confining term in the deconfined phase. Following the Klebanov-Strassler geometry, we employ a geometry, which captures the RG flow similar to QCD, to obtain the heavy quark potential by analytically continuing the string configurations into the complex plane. In addition to the attractive terms, the obtained potential has confining terms both at $T = 0$ and $T \

Binoy Krishna Patra; Himanshu Khanchandani

2015-04-01

176

Potential ecological risk of hazardous elements in different land-use urban soils of Bangladesh.  

PubMed

Soil pollution, influenced by both the natural and anthropogenic factors, significantly reduces environmental quality. In this study, six hazardous elements (Cr, Ni, Cu, As, Cd and Pb) in 12 different land-use urban soils from Bangladesh were assessed. The ranges of Cr, Ni, Cu, As, Cd and Pb in studied soils were 2.4-1258, 8.3-1044, 9.7-823, 8.7-277, 1.8-80 and 13-842mg/kg, respectively. More than 70% of soil samples exceeded the Dutch target value for Ni, Cu, As, Cd and Pb concentration in soil, indicating a potential risk to the environment. Certain indices, including the enrichment factor (EF), pollution load index (PLI) and contamination factor (Cf(i)), were used to assess the ecological risk posed by hazardous elements in soils. The mean range of PLI was 1.5-10, indicating progressive deterioration of soil due to metal contamination. However, the Cf(i) values of Cd ranged from 3.7 to 35 revealed that the examined soils were strongly impacted by Cd. Considering the severity of potential ecological risk for single metal (Er(i)), the descending order of contaminants was Cd>As>Cu>Pb>Ni>Cr. In view of the potential ecological risk (PER), soils from all land uses showed considerable to very high potential ecological risk. PMID:25613773

Islam, Saiful; Ahmed, Kawser; Habibullah-Al-Mamun; Masunaga, Shigeki

2015-04-15

177

Prediction model of potential hepatocarcinogenicity of rat hepatocarcinogens using a large-scale toxicogenomics database  

SciTech Connect

The present study was performed to develop a robust gene-based prediction model for early assessment of potential hepatocarcinogenicity of chemicals in rats by using our toxicogenomics database, TG-GATEs (Genomics-Assisted Toxicity Evaluation System developed by the Toxicogenomics Project in Japan). The positive training set consisted of high- or middle-dose groups that received 6 different non-genotoxic hepatocarcinogens during a 28-day period. The negative training set consisted of high- or middle-dose groups of 54 non-carcinogens. Support vector machine combined with wrapper-type gene selection algorithms was used for modeling. Consequently, our best classifier yielded prediction accuracies for hepatocarcinogenicity of 99% sensitivity and 97% specificity in the training data set, and false positive prediction was almost completely eliminated. Pathway analysis of feature genes revealed that the mitogen-activated protein kinase p38- and phosphatidylinositol-3-kinase-centered interactome and the v-myc myelocytomatosis viral oncogene homolog-centered interactome were the 2 most significant networks. The usefulness and robustness of our predictor were further confirmed in an independent validation data set obtained from the public database. Interestingly, similar positive predictions were obtained in several genotoxic hepatocarcinogens as well as non-genotoxic hepatocarcinogens. These results indicate that the expression profiles of our newly selected candidate biomarker genes might be common characteristics in the early stage of carcinogenesis for both genotoxic and non-genotoxic carcinogens in the rat liver. Our toxicogenomic model might be useful for the prospective screening of hepatocarcinogenicity of compounds and prioritization of compounds for carcinogenicity testing. - Highlights: >We developed a toxicogenomic model to predict hepatocarcinogenicity of chemicals. >The optimized model consisting of 9 probes had 99% sensitivity and 97% specificity. >This model enables us to detect genotoxic as well as non-genotoxic hepatocarcinogens.

Uehara, Takeki, E-mail: takeki.uehara@shionogi.co.jp [Drug Developmental Research Laboratories, Shionogi and Co., Ltd., 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825 (Japan); Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Minowa, Yohsuke; Morikawa, Yuji [Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Kondo, Chiaki; Maruyama, Toshiyuki; Kato, Ikuo [Drug Developmental Research Laboratories, Shionogi and Co., Ltd., 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825 (Japan); Nakatsu, Noriyuki; Igarashi, Yoshinobu; Ono, Atsushi [Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Hayashi, Hitomi [Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Harumi-cho, Fuchu, Tokyo 183-8509 (Japan); Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193 Gifu (Japan); Mitsumori, Kunitoshi [Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Harumi-cho, Fuchu, Tokyo 183-8509 (Japan); Yamada, Hiroshi [Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Ohno, Yasuo [National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Urushidani, Tetsuro [Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kodo, Kyotanabe, Kyoto 610-0395 (Japan)

2011-09-15

178

Evaluation of the potential difference induced between platinum electrodes with and without gamma-ray irradiation  

NASA Astrophysics Data System (ADS)

By irradiating 60Co?-rays to solutions with argon (Ar) or carbon dioxide (CO 2), it is confirmed that the potential of electrode under ?-rays shows a sharp reduction during an early period and that concentration cell is formed to give potential difference (PD) between electrodes with and without exposure. When Ar is purged through solutions, the absolute value of PD shows a linear relation with dose rate (R) on log-log scale [equation (9)] whereas there is not a good correlation between PD and R in the solution with CO 2. In the light of concentration cell thus formed, some concepts are preliminary discussed to control the adverse effect of radiation-enhanced localized corrosion taking place in nuclear power plants.

Fujita, Norihiko; Matsuura, Chihiro; Saigo, Kazuhiko

1997-11-01

179

Assessing different zeolitic adsorbents for their potential use in Kr and Xe separation  

NASA Astrophysics Data System (ADS)

Separation of Kr from Xe is an important problem in spent nuclear fuel fission gas management. The energy intensive and expensive cryogenic distillation method is currently used to separate these gases. In this thesis, we have carried out the research into appropriate sorbents for the separation of Kr and Xe using pressure swing adsorption. We have examined zeolites using gas adsorption studies as they have the potential to be more cost effective than other sorbents. Zeolites are microporous aluminosilicates and have ordered pore structures. The pores in zeolites have extra-framework cations are substantially free to move. The mobility of cations and the uniformity in pore size permits the separation and removal of gases in zeolites. In our experiment, first, we have measured adsorption isotherms with same zeolitic framework but with different cations. Second, we have measured the adsorption isotherm with different zeolitic frameworks but with same cation. Using these adsorption isotherms, we have calculated the initial heats of adsorption to find out the strength of interaction between the zeolitic framework and the gases. Finally, we have compared the difference in the initial heats of adsorption to find the suitable zeolite that has the highest selectivity of Xe over Kr. In conclusion, we have found out that K LSX seems to have higher potential among the zeolites that we have compared for the separation of Kr from Xe with the differential heats of adsorption for Xe vs Kr as ˜7.4 kJ/mol.

Alagappan, Breetha

180

Large volcanoes on Venus: Examples of geologic and structural characteristics from different classes  

NASA Technical Reports Server (NTRS)

Large volcanoes characterized by radial lava flows and similar evidence for a topographic edifice are widely distributed over the surface of Venus and geologically diverse. Based on the global identification of more than 165 examples and preliminary geologic mapping, large volcanoes range from those characterized geologically as simple lava edifices to those bearing evidence of complexly developed volcanic and structural histories. Many large volcanoes exhibit characteristics transitional to other large magnetic center types such as coronae and novae. In this study, we examine the geology and structure of several type examples of large volcanoes not addressed in previous studies which are representative of several of the morphological classes.

Crumpler, L. S.; Head, J. W.; Aubele, J. C.

1993-01-01

181

Large current difference in Au-coated vertical silicon nanowire electrode array with functionalization of peptides  

PubMed Central

Au-coated vertical silicon nanowire electrode array (VSNEA) was fabricated using a combination of bottom-up and top-down approaches by chemical vapor deposition and complementary metal-oxide-semiconductor process for biomolecule sensing. To verify the feasibility for the detection of biomolecules, Au-coated VSNEA was functionalized using peptides having a fluorescent probe. Cyclic voltammograms of the peptide-functionalized Au-coated VSNEA show a steady-state electrochemical current behavior. Because of the critically small dimension and vertically aligned nature of VSNEA, the current density of Au-coated VSNEA was dramatically higher than that of Au film electrodes. Au-coated VSNEA further showed a large current difference with and without peptides that was nine times more than that of Au film electrodes. These results indicate that Au-coated VSENA is highly effective device to detect peptides compared to conventional thin-film electrodes. Au-coated VSNEA can also be used as a divergent biosensor platform in many applications. PMID:24279451

2013-01-01

182

Modeling reactive transport of reclaimed water through large soil columns with different low-permeability layers  

NASA Astrophysics Data System (ADS)

The efficacy of different proportions of silt-loam/bentonite mixtures overlying a vadose zone in controlling solute leaching to groundwater was quantified. Laboratory experiments were carried out using three large soil columns, each packed with 200-cm-thick riverbed soil covered by a 2-cm-thick bentonite/silt-loam mixture as the low-permeability layer (with bentonite mass accounting for 12, 16 and 19 % of the total mass of the mixture). Reclaimed water containing ammonium (NH4 +), nitrate (NO3 -), organic matter (OM), various types of phosphorus and other inorganic salts was applied as inflow. A one-dimensional mobile-immobile multi-species reactive transport model was used to predict the preferential flow and transport of typical pollutants through the soil columns. The simulated results show that the model is able to predict the solute transport in such conditions. Increasing the amount of bentonite in the low-permeability layer improves the removal of NH4 + and total phosphorous (TP) because of the longer contact time and increased adsorption capacity. The removal of NH4 + and OM is mainly attributed to adsorption and biodegradation. The increase of TP and NO3 - concentration mainly results from discharge and nitrification in riverbed soils, respectively. This study underscores the role of low-permeability layers as barriers in groundwater protection. Neglect of fingers or preferential flow may cause underestimation of pollution risk.

Hu, Haizhu; Mao, Xiaomin; Barry, D. A.; Liu, Chengcheng; Li, Pengxiang

2015-03-01

183

Phytoremediation Potential of Cadmium-Contaminated Soil by Eucalyptus globulus Under Different Coppice Systems.  

PubMed

The objective of this research was to determine the phytoremediation potential of Eucalyptus globulus in Cd contaminated soil through two different harvest methods. Although replanting is more expensive than coppicing and produces less aboveground biomass, more Cd can be removed from the soil with roots removal at each harvest as the E. globulus absorbs vast majority of heavy metals in non-metabolically active parts like roots. Despite the higher cost of replanting in a single harvest, when phytoremediation efficiency and total duration are considered as important factors, the replanting treatment should be recommended as an appropriate method which can decrease the phytoremediation time obviously. PMID:25543544

Luo, Jie; Qi, Shihua; Peng, Li; Xie, Xianming

2015-03-01

184

Expression of Twist gene in human hepatocellular carcinoma cell strains of different metastatic potential  

Microsoft Academic Search

Summary  In order to investigate the role of Twist gene in the metastasis of hepatocellular carcinoma (HCC), total RNA was respectively\\u000a extracted from three HCC cell strains with different metastatic potentials, HepG2, MHCC-97L and MHCC-97H. The first strand\\u000a cDNA was synthesized by reverse transcription, which was then used as template to perform fluorescent quantitative polymerase\\u000a chain reaction (FQ-PCR). The quantity of

Qian Zhu; Hubo Xu; Qian Xu; Wei Yan; De’an Tian

2008-01-01

185

In vitro testing of the osteoinductive potential of different bony allograft preparations  

Microsoft Academic Search

Introduction  Bony allografts are used frequently in the clinic for bone defect filling, however, less comparative data concerning their\\u000a osteoinductive potential are available.\\u000a \\u000a \\u000a \\u000a Aim  The purpose of the present study was the comparative analysis of different allograft preparations. From five donors, we investigated\\u000a fresh-frozen cancellous bone (native), peracetic acid–ethanol sterilized (PES) cancellous bone, cortical bone and demineralised\\u000a bone matrix (DBM). In addition,

N. Bormann; A. Pruss; G. Schmidmaier; Britt Wildemann

2010-01-01

186

Consistency of mixing height retrieved over a large spatial domain from different data sources  

NASA Astrophysics Data System (ADS)

The monitoring of GreenHouse Gases (GHG) fluxes over large domains is performed coupling measurements with transport models. A key parameter, for successfully quantifying the fluxes is the altitude of the capping inversion, or the mixing height (MH). This parameter is commonly estimated as a diagnostic variable within global models, or estimated using radiosonde data. Both these methods have problems in representing the MH. In particular the time evolution and the spatial representation are the weakest aspects. Within the context of the Integrated Carbon Observation System (ICOS), a network of measurement stations is going to be created. Together with a complete equipment of instruments for measuring GHG concentrations and meteorological quantities, it is planed to monitor the MH using ceilometers and lidars. Ceilometers are a less expensive version of lidars, they are capable to estimate aerosolic load and within almost the first two kilometers the molecular density. The estimations are obtained looking for relevant time and space fluctuations of aerosol concentration. This is equivalent to placing the MH over an strong variation of the measured signal. So the most of the algorithms for locating MH are edge detection algorithms. The evaluation of the MH, estimated with different algorithms applied to optical data, shows bad agreement with the estimate performed on radiosonde data. However, a deeper study on the automated methods used on radiosonde data reveals that the commonly used algorithms, based on different implementations of Richardson Bulk Number method, are not reliable or suitable for evaluating results of other methods. The use of optical instruments for estimating MH has several limitations: multiple edges are commonly detected and a selection criteria is required; depending on the stability of the boundary layer MH can be outside the detection limits of the instrument; clouds and other water condensations phenomena can prevent the estimation of MH. Applications of such instruments is tested over a wide domain covering the German Weather Service network of ceilometers and the estimations are compared to different methods of estimating MH, in particular: geostatistical interpolation of MH estimated with radiosonde; distance weighted interpolations of MH estimated with radiosonde; direct comparison of co-located ceilometer and radiosonde. The results reveal the need of developing a more appropriate approach for using both radiosonde and optical methods in an automated context.

Biavati, Gionata; Feist, Dietrich G.

2014-05-01

187

Large Sex Differences in Chicken Behavior and Brain Gene Expression Coincide with Few Differences in Promoter DNA-Methylation  

PubMed Central

While behavioral sex differences have repeatedly been reported across taxa, the underlying epigenetic mechanisms in the brain are mostly lacking. Birds have previously shown to have only limited dosage compensation, leading to high sex bias of Z-chromosome gene expression. In chickens, a male hyper-methylated region (MHM) on the Z-chromosome has been associated with a local type of dosage compensation, but a more detailed characterization of the avian methylome is limiting our interpretations. Here we report an analysis of genome wide sex differences in promoter DNA-methylation and gene expression in the brain of three weeks old chickens, and associated sex differences in behavior of Red Junglefowl (ancestor of domestic chickens). Combining DNA-methylation tiling arrays with gene expression microarrays we show that a specific locus of the MHM region, together with the promoter for the zinc finger RNA binding protein (ZFR) gene on chromosome 1, is strongly associated with sex dimorphism in gene expression. Except for this, we found few differences in promoter DNA-methylation, even though hundreds of genes were robustly differentially expressed across distantly related breeds. Several of the differentially expressed genes are known to affect behavior, and as suggested from their functional annotation, we found that female Red Junglefowl are more explorative and fearful in a range of tests performed throughout their lives. This paper identifies new sites and, with increased resolution, confirms known sites where DNA-methylation seems to affect sexually dimorphic gene expression, but the general lack of this association is noticeable and strengthens the view that birds do not have dosage compensation. PMID:24782041

Nätt, Daniel; Agnvall, Beatrix; Jensen, Per

2014-01-01

188

Potential of mean force of association of large hydrophobic particles: toward the nanoscale limit.  

PubMed

The potentials of mean force (PMFs) were determined, in both water with the TIP3P water model and in vacuo, for systems involving formation of nonpolar dimers composed of bicyclooctane, adamantane (both an all-atom model and a sphere with the radius of 3.4 A representing adamantane), and fullerene, respectively. A series of umbrella-sampling molecular dynamics simulations with the AMBER force field were carried out for each pair under both environmental conditions. The PMFs were calculated by using the weighted histogram analysis method. The results were compared with our previously determined PMF for neopentane. The shape of the PMFs for dimers of all four nonpolar molecules is characteristic of hydrophobic interactions with contact and solvent-separated minima and desolvation maxima. The positions of all these minima and maxima change with the size of the nonpolar molecule; for larger molecules they shift toward larger distances. Comparison of the PMFs of the bicyclooctane, adamantane, and fullerene dimers in water and in vacuo shows that hydrophobic interactions in each dimer are different from that for the dimer of neopentane. Interactions in the bicyclooctane, adamantane, and fullerene dimers are stronger in vacuo than in water. These dimers cannot be treated as classical, spherical, hydrophobic objects. The solvent contribution to the PMF was also computed by subtracting the PMF determined in vacuo from that in explicit solvent. The solvent contribution to the PMFs of bicyclooctane, adamantane, and fullerene is positive, as opposed to that of neopentane. The water molecules in the first solvation sphere of both adamantane and neopentane dimers are more ordered as compared to bulk water, with their dipole moments pointing away from the surface of the dimers. The average number of hydrogen bonds per water molecule in the first hydration shell of adamantane is smaller compared to that in bulk water, but this shell is thicker for all-atom adamantane than for neopentane or a spherical model of adamantane. In the second hydration shell, the average number of hydrogen bonds is greater compared to that in bulk water only for neopentane and a spherical model of adamantane but not for the all-atom model. The strength of the hydrophobic interactions shows a linear dependence on the number of carbon atoms both in water and in vacuo. Smaller nonpolar particles interact more strongly in water than in vacuo. For larger molecules, such as bicyclooctane, adamantane and fullerene, the reversed tendency is observed. PMID:20039620

Makowski, Mariusz; Czaplewski, Cezary; Liwo, Adam; Scheraga, Harold A

2010-01-21

189

Potential Climatic Impacts and Reliability of Very Large-Scale Wind Farms  

E-print Network

Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG) emission technologies such as wind energy. The widespread availability of wind power has ...

Wang, Chien

190

Potential Climatic Impacts and Reliability of Large-Scale Offshore Wind Farms  

E-print Network

The vast availability of wind power has fueled substantial interest in this renewable energy source as a potential near-zero greenhouse gas emission technology for meeting future world energy needs while addressing the ...

Wang, Chien

191

Heavy Quark Potential at Finite Temperature in a Dual Gravity Closer to Large N QCD  

E-print Network

In gauge-gravity duality, heavy quark potential at finite temperature is usually calculated with the pure AdS background, which does not capture the renormalisation group (RG) running in the gauge theory part and the potential also does not contain any confining term in the deconfined phase. Following the developments in \\cite{KS}, a geometry was contructed recently in \\cite{ Mia:NPB2010, Mia:PRD2010}, which captures the RG flow similar to QCD and we employ their geometry to obtain the heavy quark potential by analytically continuing the string configurations into the complex plane. In addition to the attractive terms, the obtained potential has confining terms both at $T=0$ and $T \

Binoy Krishna Patra; Himanshu Khanchandani

2014-12-16

192

The potential of large-scale open-sea cultivation of benthic algae  

Microsoft Academic Search

There is an area of open water about 200 miles long and 20 miles wide along the Florida Gulf coast that is eminently adapted to large-scale mariculture of tropical benthic algae. It is suggested that this is a unique area for the development of a large-scale system of planting, harvesting, and processing certain fast-growing tropical marine algae of value as

H. J. Humm

1979-01-01

193

Estimating sugarcane yield potential using an in-season determination of normalized difference vegetative index.  

PubMed

Estimating crop yield using remote sensing techniques has proven to be successful. However, sugarcane possesses unique characteristics; such as, a multi-year cropping cycle and plant height-limiting for midseason fertilizer application timing. Our study objective was to determine if sugarcane yield potential could be estimated using an in-season estimation of normalized difference vegetative index (NDVI). Sensor readings were taken using the GreenSeeker® handheld sensor from 2008 to 2011 in St. Gabriel and Jeanerette, LA, USA. In-season estimates of yield (INSEY) values were calculated by dividing NDVI by thermal variables. Optimum timing for estimating sugarcane yield was between 601-750 GDD. In-season estimated yield values improved the yield potential (YP) model compared to using NDVI. Generally, INSEY value showed a positive exponential relationship with yield (r(2) values 0.48 and 0.42 for cane tonnage and sugar yield, respectively). When models were separated based on canopy structure there was an increase the strength of the relationship for the erectophile varieties (r(2) 0.53 and 0.47 for cane tonnage and sugar yield, respectively); however, the model for planophile varieties weakened slightly. Results of this study indicate using an INSEY value for predicting sugarcane yield shows potential of being a valuable management tool for sugarcane producers in Louisiana. PMID:22969359

Lofton, Josh; Tubana, Brenda S; Kanke, Yumiko; Teboh, Jasper; Viator, Howard; Dalen, Marilyn

2012-01-01

194

Investigation of potential waste material insulating properties at different temperature for thermal storage application  

NASA Astrophysics Data System (ADS)

Thermal energy storage system (TES) is developed to extend the operation of power generation. TES system is a key component in a solar energy power generation plant, but the main issue in designing the TES system is its thermal capacity of storage materials, e.g. insulator. This study is focusing on the potential waste material acts as an insulator for thermal energy storage applications. As the insulator is used to absorb heat, it is needed to find suitable material for energy conversion and at the same time reduce the waste generation. Thus, a small-scale experimental testing of natural cooling process of an insulated tank within a confined room is conducted. The experiment is repeated by changing the insulator from the potential waste material and also by changing the heat transfer fluid (HTF). The analysis presented the relationship between heat loss and the reserved period by the insulator. The results show the percentage of period of the insulated tank withstands compared to tank insulated by foam, e.g. newspaper reserved the period of 84.6% as much as foam insulated tank to withstand the heat transfer of cooking oil to the surrounding. The paper finally justifies the most potential waste material as an insulator for different temperature range of heat transfer fluid.

Ali, T. Z. S.; Rosli, A. B.; Gan, L. M.; Billy, A. S.; Farid, Z.

2013-12-01

195

Estimating Sugarcane Yield Potential Using an In-Season Determination of Normalized Difference Vegetative Index  

PubMed Central

Estimating crop yield using remote sensing techniques has proven to be successful. However, sugarcane possesses unique characteristics; such as, a multi-year cropping cycle and plant height-limiting for midseason fertilizer application timing. Our study objective was to determine if sugarcane yield potential could be estimated using an in-season estimation of normalized difference vegetative index (NDVI). Sensor readings were taken using the GreenSeeker® handheld sensor from 2008 to 2011 in St. Gabriel and Jeanerette, LA, USA. In-season estimates of yield (INSEY) values were calculated by dividing NDVI by thermal variables. Optimum timing for estimating sugarcane yield was between 601–750 GDD. In-season estimated yield values improved the yield potential (YP) model compared to using NDVI. Generally, INSEY value showed a positive exponential relationship with yield (r2 values 0.48 and 0.42 for cane tonnage and sugar yield, respectively). When models were separated based on canopy structure there was an increase the strength of the relationship for the erectophile varieties (r2 0.53 and 0.47 for cane tonnage and sugar yield, respectively); however, the model for planophile varieties weakened slightly. Results of this study indicate using an INSEY value for predicting sugarcane yield shows potential of being a valuable management tool for sugarcane producers in Louisiana. PMID:22969359

Lofton, Josh; Tubana, Brenda S.; Kanke, Yumiko; Teboh, Jasper; Viator, Howard; Dalen, Marilyn

2012-01-01

196

Apollo 14 regolith breccias - Different glass populations and their potential for charting space time variations  

NASA Technical Reports Server (NTRS)

Apollo 14 regolith breccias (14313, 14307, 14301, 14049, 14047) have been found to have different populations of nonagglutinitic, mare-derived glasses. These variations appear to not only reflect different source regoliths but also different closure ages for these breccias. Based upon these different glass populations, 14301 is inferred to have a closure age sometime during the epoch of mare volcanism. All of the other four breccias were formed after the termination of mare volcanism with a possible age sequence from old to young of the following: 14307, 14313, 14049, 14047. Due to the relative simplicity of acquiring high-quality chemical data on large numbers of glasses by electron microprobe, mare glass populations allow: (1) classification of regolith breccias with respect to provenance and (2) estimation of their relative and absolute closure ages. The determination of (Ar-40)-(Ar-39) ages on individual glass spherules within breccias using the laser probe should in the future prove to be a promising extension of the present study.

Delano, John W.

1988-01-01

197

Repetition and brain potentials when recognizing natural scenes: task and emotion differences  

PubMed Central

Repetition has long been known to facilitate memory performance, but its effects on event-related potentials (ERPs), measured as an index of recognition memory, are less well characterized. In Experiment 1, effects of both massed and distributed repetition on old–new ERPs were assessed during an immediate recognition test that followed incidental encoding of natural scenes that also varied in emotionality. Distributed repetition at encoding enhanced both memory performance and the amplitude of an old–new ERP difference over centro-parietal sensors. To assess whether these repetition effects reflect encoding or retrieval differences, the recognition task was replaced with passive viewing of old and new pictures in Experiment 2. In the absence of an explicit recognition task, ERPs were completely unaffected by repetition at encoding, and only emotional pictures prompted a modestly enhanced old–new difference. Taken together, the data suggest that repetition facilitates retrieval processes and that, in the absence of an explicit recognition task, differences in old–new ERPs are only apparent for affective cues. PMID:22842817

Bradley, Margaret M.; Codispoti, Maurizio; Karlsson, Marie; Lang, Peter J.

2013-01-01

198

Action potential configuration in heart papillary muscles from female rats in different thyroid states.  

PubMed

We have studied the effects of thyroidectomy and the in vivo administration of different triiodothyronine (T3) doses in thyroidectomized female rats on electrophysiological properties, measured in vitro, of the anterior and posterior papillary muscle fibers from the right ventricle. In each thyroid state, the action potential duration (APD) measured by stimulating at 1 Hz was shorter for the posterior papillary muscle. APD from both preparations was found significantly lengthened in thyroidectomized animals in comparison to euthyroid controls. APD was shortened owing to treatment of thyroidectomized rats with T3 doses up to 10 micrograms/100 g body weight every second day. Treatment with larger doses of T3 tended to restore the values of APD found for ventricular fibres from both controls and thyroidectomized animals treated with substitutive T3 doses (5 micrograms/100 g body weight every second day). As the stimulation rate was increased from 1 to 5 Hz, APD increased in both preparations of all groups. The changes were of different amounts but the APD difference between the rat groups, which were significant at 1 Hz, remained significant at 5 Hz, while the differences between anterior and posterior preparations were cancelled in animals treated with 50 micrograms of T3 and reversed in those treated with 100 micrograms. PMID:9224547

Di Meo, S; de Martino Rosaroll, P; Venditti, P; Balestrieri, M; De Leo, T

1997-02-01

199

Torque measurements reveal large process differences between materials during high solid enzymatic hydrolysis of pretreated lignocellulose  

PubMed Central

Background A common trend in the research on 2nd generation bioethanol is the focus on intensifying the process and increasing the concentration of water insoluble solids (WIS) throughout the process. However, increasing the WIS content is not without problems. For example, the viscosity of pretreated lignocellulosic materials is known to increase drastically with increasing WIS content. Further, at elevated viscosities, problems arise related to poor mixing of the material, such as poor distribution of the enzymes and/or difficulties with temperature and pH control, which results in possible yield reduction. Achieving good mixing is unfortunately not without cost, since the power requirements needed to operate the impeller at high viscosities can be substantial. This highly important scale-up problem can easily be overlooked. Results In this work, we monitor the impeller torque (and hence power input) in a stirred tank reactor throughout high solid enzymatic hydrolysis (< 20% WIS) of steam-pretreated Arundo donax and spruce. Two different process modes were evaluated, where either the impeller speed or the impeller power input was kept constant. Results from hydrolysis experiments at a fixed impeller speed of 10 rpm show that a very rapid decrease in impeller torque is experienced during hydrolysis of pretreated arundo (i.e. it loses its fiber network strength), whereas the fiber strength is retained for a longer time within the spruce material. This translates into a relatively low, rather WIS independent, energy input for arundo whereas the stirring power demand for spruce is substantially larger and quite WIS dependent. By operating the impeller at a constant power input (instead of a constant impeller speed) it is shown that power input greatly affects the glucose yield of pretreated spruce whereas the hydrolysis of arundo seems unaffected. Conclusions The results clearly highlight the large differences between the arundo and spruce materials, both in terms of needed energy input, and glucose yields. The impact of power input on glucose yield is furthermore shown to vary significantly between the materials, with spruce being very affected while arundo is not. These findings emphasize the need for substrate specific process solutions, where a short pre-hydrolysis (or viscosity reduction) might be favorable for arundo whereas fed-batch might be a better solution for spruce. PMID:22867035

2012-01-01

200

Combined use of two membrane-potential-sensitive dyes for determination of the Galvani potential difference across a biomimetic oil/water interface.  

PubMed

The fluorescence behavior of anionic membrane-potential-sensitive dyes, bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC4(3)) and bis-(1,3-diethylthiobarbituric acid)trimethine oxonol (DiSBAC2(3)), at a biomimetic 1,2-dichloroethane (DCE)/water (W) interface was studied by the mean of potential-modulated fluorescence (PMF) spectroscopy. The respective dyes gave a well-defined PMF signal due to the adsorption/desorption at the DCE/W interface. It was also found that the potentials where the two dyes gave the PMF signals were different by about 100 mV. We then attempted a combined use of the two dyes for determination of the Galvani potential difference across the DCE/W interface. When 40 ?M DiBAC4(3) and 15 ?M DiSBAC2(3) were initially added to the W phase, distinctly different spectra were obtained for different interfacial potentials. The ratio of the PMF signal intensities at 530 and 575 nm (the fluorescence maximum wavelengths for the respective dyes) showed a clear dependence on the interfacial potential. These results suggested the potential utility of the combined use of two dyes for the determination of membrane potentials in vivo. PMID:24687435

Yoshimura, Tatsuya; Nagatani, Hirohisa; Osakai, Toshiyuki

2014-05-01

201

Phenotypic identification of subclones in multiple myeloma with different chemoresistant, cytogenetic and clonogenic potential.  

PubMed

Knowledge about clonal diversity and selection is critical to understand multiple myeloma (MM) pathogenesis, chemoresistance and progression. If targeted therapy becomes reality, identification and monitoring of intraclonal plasma cell (PC) heterogeneity would become increasingly demanded. Here we investigated the kinetics of intraclonal heterogeneity among 116 MM patients using 23-marker multidimensional flow cytometry (MFC) and principal component analysis, at diagnosis and during minimal residual disease (MRD) monitoring. Distinct phenotypic subclones were observed in 35/116 (30%) newly diagnosed MM patients. In 10/35 patients, persistent MRD was detected after 9 induction cycles, and longitudinal comparison of patient-paired diagnostic vs MRD samples unraveled phenotypic clonal tiding after therapy in half (5/10) of the patients. After demonstrating selection of distinct phenotypic subsets by therapeutic pressure, we investigated whether distinct fluorescence-activated cell-sorted PC subclones had different clonogenic and cytogenetic profiles. In half (5/10) of the patients analyzed, distinct phenotypic subclones showed different clonogenic potential when co-cultured with stromal cells, and in 6/11 cases distinct phenotypic subclones displayed unique cytogenetic profiles by interphase fluorescence in situ hybridization, including selective del(17p13). Collectively, we unravel potential therapeutic selection of preexisting diagnostic phenotypic subclones during MRD monitoring; because phenotypically distinct PCs may show different clonogenic and cytogenetic profiles, identification and follow-up of unique phenotypic-genetic myeloma PC subclones may become relevant for tailored therapy.Leukemia advance online publication, 5 December 2014; doi:10.1038/leu.2014.321. PMID:25388955

Paíno, T; Paiva, B; Sayagués, J M; Mota, I; Carvalheiro, T; Corchete, L A; Aires-Mejía, I; Pérez, J J; Sanchez, M L; Barcena, P; Ocio, E M; San-Segundo, L; Sarasquete, M E; García-Sanz, R; Vidriales, M-B; Oriol, A; Hernández, M-T; Echeveste, M-A; Paiva, A; Blade, J; Lahuerta, J-J; Orfao, A; Mateos, M-V; Gutiérrez, N C; San-Miguel, J F

2014-11-12

202

Practical hyperdynamics method for systems with large changes in potential energy.  

PubMed

A practical hyperdynamics method is proposed to accelerate systems with highly endothermic and exothermic reactions such as hydrocarbon pyrolysis and oxidation reactions. In this method, referred to as the "adaptive hyperdynamics (AHD) method," the bias potential parameters are adaptively updated according to the change in potential energy. The approach is intensively examined for JP-10 (exo-tetrahydrodicyclopentadiene) pyrolysis simulations using the ReaxFF reactive force field. Valid boost parameter ranges are clarified as a result. It is shown that AHD can be used to model pyrolysis at temperatures as low as 1000 K while achieving a boost factor of around 10(5). PMID:25527921

Hirai, Hirotoshi

2014-12-21

203

Motor unit potential morphology differences in individuals with non-specific arm pain and lateral epicondylitis  

PubMed Central

Background The pathophysiology of non-specific arm pain (NSAP) is unclear and the diagnosis is made by excluding other specific upper limb pathologies, such as lateral epicondylitis or cervical radiculopathy. The purpose of this study was to determine: (i) if the quantitative parameters related to motor unit potential morphology and/or motor unit firing patterns derived from electromyographic (EMG) signals detected from an affected muscle of patients with NSAP are different from those detected in the same muscle of individuals with lateral epicondylitis (LE) and/or control subjects and (ii) if the quantitative EMG parameters suggest that the underlying pathophysiology in NSAP is either myopathic or neuropathic in nature. Methods Sixteen subjects with NSAP, 11 subjects with LE, eight subjects deemed to be at-risk for developing a repetitive strain injury, and 37 control subjects participated. A quantitative electromyography evaluation was completed using decomposition-based quantitative electromyography (DQEMG). Needle- and surface-detected EMG signals were collected during low-level isometric contractions of the extensor carpi radialis brevis (ECRB) muscle. DQEMG was used to extract needle-detected motor unit potential trains (MUPTs), and needle-detected motor unit potential (MUP) and surface detected motor unit potential (SMUP) morphology and motor unit (MU) firing rates were compared among the four groups using one-way analysis of variance (ANOVA). Post hoc analyses were performed using Tukey's pairwise comparisons. Results Significant group differences were found for all MUP variables and for MU firing rate (p < 0.006). The post-hoc analyses revealed that patients with NSAP had smaller MUP amplitude and SMUP amplitude and area compared to the control and LE groups (p < 0.006). MUP duration and AAR values were significantly larger in the NSAP, LE and at-risk groups compared to the control group (p < 0.006); while MUP amplitude, duration and AAR values were smaller in the NSAP compared to the LE group. SMUP duration was significantly shorter in the NSAP group compared to the control group (p < 0.006). NSAP, LE and at-risk subjects had lower mean MU firing rates than the control subjects (p < 0.006). Conclusion The size-related parameters suggest that the NSAP group had significantly smaller MUPs and SMUPs than the control and LE subjects. Smaller MUPs and SMUPs may be indicative of muscle fiber atrophy and/or loss. A prospective study is needed to confirm any causal relationship between smaller MUPs and SMUPs and NSAP as found in this work. PMID:19087309

Calder, Kristina M; Stashuk, Daniel W; McLean, Linda

2008-01-01

204

Sex differences in event-related potentials and attentional biases to emotional facial stimuli  

PubMed Central

Attentional processes play an important role in the processing of emotional information. Previous research reported attentional biases during stimulus processing in anxiety and depression. However, sex differences in the processing of emotional stimuli and higher prevalence rates of anxiety disorders among women, compared to men, suggest that attentional biases may also differ between the two sexes. The present study used a modified version of the dot probe task with happy, angry, and neutral facial stimuli to investigate the time course of attentional biases in healthy volunteers. Moreover, associations of attentional biases with alexithymia were examined on the behavioral and physiological level. Event-related potentials were measured while 21 participants (11 women) performed the task, utilizing also for the first time a difference wave approach in the analysis to highlight emotion-specific aspects. Women showed overall enhanced probe P1 amplitudes compared to men, in particular after rewarding facial stimuli. Using the difference wave approach, probe P1 amplitudes appeared specifically enhanced with regard to congruently presented happy facial stimuli among women, compared to men. Both methods yielded enhanced probe P1 amplitudes after presentation of the emotional stimulus in the left compared to the right visual hemifield. Probe P1 amplitudes correlated negatively with self-reported alexithymia, most of these correlations were only observable in women. Our results suggest that women orient their attention to a greater extent to facial stimuli than men and corroborate that alexithymia is a correlate of reduced emotional reactivity on a neuronal level. We recommend using a difference wave approach when addressing attentional processes of orientation and disengagement also in future studies. PMID:25566151

Pfabigan, Daniela M.; Lamplmayr-Kragl, Elisabeth; Pintzinger, Nina M.; Sailer, Uta; Tran, Ulrich S.

2014-01-01

205

Differences in early sensory-perceptual processing in synesthesia: a visual evoked potential study.  

PubMed

Synesthesia is a condition where stimulation of a single sensory modality or processing stream elicits an idiosyncratic, yet reliable perception in one or more other modalities or streams. Various models have been proposed to explain synesthesia, which have in common aberrant cross-activation of one cortical area by another. This has been observed directly in cases of linguistic-color synesthesia as cross-activation of the 'color area', V4, by stimulation of the grapheme area. The underlying neural substrates that mediate cross-activations in synesthesia are not well understood, however. In addition, the overall integrity of the visual system has never been assessed and it is not known whether wider differences in sensory-perceptual processing are associated with the condition. To assess whether fundamental differences in perceptual processing exist in synesthesia, we utilised high-density 128-channel electroencephalography (EEG) to measure sensory-perceptual processing using stimuli that differentially bias activation of the magnocellular and parvocellular pathways of the visual system. High and low spatial frequency gratings and luminance-contrast squares were presented to 15 synesthetes and 15 controls. We report, for the first time, early sensory-perceptual differences in synesthetes relative to non-synesthete controls in response to simple stimuli that do not elicit synesthetic color experiences. The differences are manifested in the early sensory components of the visual evoked potential (VEP) to stimuli that bias both magnocellular and parvocellular responses, but are opposite in direction, suggesting a differential effect on these two pathways. We discuss our results with reference to widespread connectivity differences as a broader phenotype of synesthesia. PMID:18723094

Barnett, Kylie J; Foxe, John J; Molholm, Sophie; Kelly, Simon P; Shalgi, Shani; Mitchell, Kevin J; Newell, Fiona N

2008-11-15

206

International Large-Scale Assessments: Challenges in Reporting and Potentials for Secondary Analysis  

ERIC Educational Resources Information Center

International Large-Scale Assessments (ILSAs) have been used to draw comparisons among countries on a variety of topics in education and, more broadly, for example, in adolescent development. These assessments can inform the public about influential factors on the micro and macro levels, foster interdisciplinary and international collaboration,…

Torney-Purta, Judith; Amadeo, Jo-Ann

2013-01-01

207

A potential economical substrate for large-scale production of Bacillus thuringiensis kurstaki for caterpillar control  

Microsoft Academic Search

Bacillus thuringiensis kurstaki has been widely used in caterpillar control programs. Large-scale production of this bacterium is expensive because of the high cost of the raw materials used in the medium. In this study, we attempted to develop an economical medium, based on inexpensive, locally available raw materials using a 3-L fermenter. Parthenium hysterophorus L. extract based culture medium resulted

Bishwajeet Paul; Sangeeta Paul

2011-01-01

208

Potential effects of climate change and eutrophication on a large subtropical shallow lake  

Microsoft Academic Search

In many aquatic ecosystems, increased nutrient loading has caused eutrophication, which is reflected in the trophic structure of the ecosystem. In Lake Mangueira, a large shallow subtropical lake in Brazil, nutrient loading has also increased, but it is still unclear what the effects of this increase will be and how this relates to climate change. To evaluate the effects of

Carlos R. Fragoso; David M. L. Motta Marques; Tiago Finkler Ferreira; Jan H. Janse; Egbert H. van Nes

2011-01-01

209

Potential impacts of the Deepwater Horizon oil spill on large pelagic fishes  

Microsoft Academic Search

Biogeographical analyses provide insights on how the Deepwater Horizon oil spill impacted large pelagic fishes. We georeferenced historical ichthyoplankton surveys and published literature to map the spawning and larval areas of bluefin tuna, swordfish, blue marlin and whale shark sightings in the Gulf of Mexico with daily satellite-derived images detecting surface oil. The oil spill covered critical areas used by

Sarrah Frias-Torres; Charles R. Bostater Jr.

2011-01-01

210

A test of stress, cues, and re-exposure to large wins as potential reinstaters of suboptimal decision making in rats  

PubMed Central

The present experiment investigated potential reinstaters of suboptimal economic decision making in rats. Rats were first trained on a version of the rat Gambling Task under conditions designed to promote choice of a suboptimal option that occasionally resulted in large “wins” (four sucrose pellets). In a second phase, preference for this economically suboptimal option was reduced by substantially increasing the probability of punishment when this option was chosen. Then, three events were tested for their ability to reinstate choice of the suboptimal option. A brief period of re-exposure to a high frequency of large wins significantly increased choice of the suboptimal option. The pharmacological stressor yohimbine did not reinstate suboptimal choice, but did increase impulsive action as indexed by premature responding. Presentation of cues previously associated with large wins did not alter behavior. Results suggest reinstaters of suboptimal choice may differ from reinstaters of extinguished drug- and food-seeking behavior.

Connolly, Nina P.; Kim, Jung S.; Tunstall, Brendan J.; Kearns, David N.

2015-01-01

211

Large diffuse halos in time-dependent space-charge potentials with colored noise  

SciTech Connect

We explore the potential impact of colored noise on space-charge-induced halo formation. By coupling particle orbits to parametric resonance, colored noise due to space-charge fluctuations and/or imperfections in the beamline can eject particles to much larger amplitudes than would be inferred from parametric resonance alone.

Courtlandt Bohn and Ioannis V. Sideris

2003-05-22

212

Manual and automated methods for identifying potentially preventable readmissions: a comparison in a large healthcare system  

PubMed Central

Background Identification of potentially preventable readmissions is typically accomplished through manual review or automated classification. Little is known about the concordance of these methods. Methods We manually reviewed 459 30-day, all-cause readmissions at 18 Kaiser Permanente Northern California hospitals, determining potential preventability through a four-step manual review process that included a chart review tool, interviews with patients, their families, and treating providers, and nurse reviewer and physician evaluation of findings and determination of preventability on a five-point scale. We reassessed the same readmissions with 3 M’s Potentially Preventable Readmission (PPR) software. We examined between-method agreement and the specificity and sensitivity of the PPR software using manual review as the reference. Results Automated classification and manual review respectively identified 78% (358) and 47% (227) of readmissions as potentially preventable. Overall, the methods agreed about the preventability of 56% (258) of readmissions. Using manual review as the reference, the sensitivity of PPR was 85% and specificity was 28%. Conclusions Concordance between methods was not high enough to replace manual review with automated classification as the primary method of identifying preventable 30-day, all-cause readmission for quality improvement purposes. PMID:24708889

2014-01-01

213

Troll horizontal well tests demonstrate large production potential from thin oil zones  

SciTech Connect

This paper presents the results of two long-term horizontal well tests in the Troll field. Planning and evaluation of the tests and simulation of and consequences on field development are summarized. The two tests demonstrated significant production potential from 12- to 22-m oil columns and verified the pretest assumption that one horizontal well could replace four vertical wells.

Seines, K.; Lien, S.C.; Haug, B.T. (Norsk Hydro A/S, Oslo (Norway))

1994-05-01

214

Interannual variation in climate-potential net primary productivity relationships in differing ecosystems of California  

SciTech Connect

The seasonality and interannual variation in potential net primary production (NPP) were examined in differing vegetation types in California over three years of contrasting precipitation using co-registered maps of climate, vegetation, and 1km biweekly NDVI derived from high resolution satellite AVHRR data. Differences in seasonality of the vegetation types (annual grassland, chamise chaparral, deciduous oak woodland, and evergreen oak) were clearly evident and corresponded well to patterns observed in field studies. In years and locations having high precipitation the annual peak in NDVI occurred later in all vegetation classes. The annual sum of biweekly NDVI was correlated with annual precipitation in all vegetation types, although the slopes and intercepts of the regressions differed among types. Annual grassland showed the largest increase in sumNDVI per unit increase in total precipitation and most of the variation in grassland sumNDVI was explained by variation in autumn precipitation. In general the ratio of sumNDVI to annual precipitation was dependent on the temporal distribution of precipitation with respect to the long-term average pattern. Published relationships between precipitation and NPP were used to develop equations relating annual NDVI sum to NPP.

Koch, G.W.; Randerson, J.T. (Stanford Univ. Carnegie Institution of Plant Biology, CA (United States))

1994-06-01

215

Large-scale controls on potential respiration and denitrification in riverine floodplains  

PubMed Central

Restoration measures of deteriorated river ecosystems generally aim at increasing the spatial heterogeneity and connectivity of these systems in order to increase biodiversity and ecosystem stability. While this is believed to benefit overall ecological integrity, consequences of such restoration projects on biogeochemical processes per se (i.e. ecosystem functioning) in fluvial systems are rarely considered. We address these issues by evaluating the characteristics of surface water connection between side arms and the main river channel in a former braided river section and the role and degree of connectivity (i.e. duration of surface water connection) on the sediment biogeochemistry. We hypothesized that potential respiration and denitrification would be controlled by the degree of hydrological connectivity, which was increased after floodplain restoration. We measured potential microbial respiration (SIR) and denitrification (DEA) and compared a degraded floodplain section of the Danube River with a reconnected and restored floodplain in the same river section. Re-establishing surface water connection altered the controls on sediment microbial respiration and denitrification ultimately impacting potential microbial activities. Meta-variables were created to characterize the effects of hydrology, morphology, and the available carbon and nutrient pools on potential microbial processing. Mantel statistics and path analysis were performed and demonstrate a hierarchy where the effects of hydrology on the available substrates and microbial processing are mediated by the morphology of the floodplain. In addition, these processes are highest in the least connected sites. Surface water connection, mediated by morphology regulates the potential denitrification rate and the ratio of N2O to N2 emissions, demonstrating the effects of restoration in floodplain systems. PMID:23565037

Welti, Nina; Bondar-Kunze, Elisabeth; Singer, Gabriel; Tritthart, Michael; Zechmeister-Boltenstern, Sophie; Hein, Thomas; Pinay, Gilles

2012-01-01

216

Transcript profiling of candidate genes in testis of pigs exhibiting large differences in androstenone levels  

PubMed Central

Background Boar taint is an unpleasant odor and flavor of the meat and occurs in a high proportion of uncastrated male pigs. Androstenone, a steroid produced in testis and acting as a sex pheromone regulating reproductive function in female pigs, is one of the main compounds responsible for boar taint. The primary goal of the present investigation was to determine the differential gene expression of selected candidate genes related to levels of androstenone in pigs. Results Altogether 2560 boars from the Norwegian Landrace and Duroc populations were included in this study. Testicle samples from the 192 boars with most extreme high or low levels of androstenone in fat were used for RNA extraction, and 15 candidate genes were selected and analyzed by real-competitive PCR analysis. The genes Cytochrome P450 c17 (CYP17A1), Steroidogenic acute regulatory protein (STAR), Aldo-keto reductase family 1 member C4 (AKR1C4), Short-chain dehydrogenase/reductase family member 4 (DHRS4), Ferritin light polypeptide (FTL), Sulfotransferase family 2A, dehydroepiandrosterone-preferring member 1 (SULT2A1), Cytochrome P450 subfamily XIA polypeptide 1 (CYP11A1), Cytochrome b5 (CYB5A), and 17-beta-Hydroxysteroid dehydrogenase IV (HSD17B4) were all found to be significantly (P < 0.05) up-regulated in high androstenone boars in both Duroc and Landrace. Furthermore, Cytochrome P450 c19A2 (CYP19A2) was down-regulated and progesterone receptor membrane component 1 (PGRMC1) was up-regulated in high-androstenone Duroc boars only, while CYP21 was significantly down-regulated (2.5) in high-androstenone Landrace only. The genes Nuclear Receptor co-activator 4 (NCOA4), Sphingomyrlin phosphodiesterase 1 (SMPD1) and 3?-hydroxysteroid dehydrogenase (HSD3B) were not significantly differentially expressed in any breeds. Additionally, association studies were performed for the genes with one or more detected SNPs. Association between SNP and androstenone level was observed in CYB5A only, suggesting cis-regulation of the differential transcription in this gene. Conclusion A large pig material of highly extreme androstenone levels is investigated. The current study contributes to the knowledge about which genes that is differentially expressed regard to the levels of androstenone in pigs. Results in this paper suggest that several genes are important in the regulation of androstenone level in boars and warrant further evaluation of the above mentioned candidate genes, including analyses in different breeds, identification of causal mutations and possible gene interactions. PMID:20100319

2010-01-01

217

Examination of Sex Differences in a Large Sample of Young Children with Autism Spectrum Disorder and Typical Development  

ERIC Educational Resources Information Center

Despite consistent and substantive research documenting a large male to female ratio in Autism Spectrum Disorder (ASD), only a modest body of research exists examining sex differences in characteristics. This study examined sex differences in developmental functioning and early social communication in children with ASD as compared to children with…

Reinhardt, Vanessa P.; Wetherby, Amy M.; Schatschneider, Christopher; Lord, Catherine

2015-01-01

218

An Application of the Difference Potentials Method to Solving External Problems in CFD  

NASA Technical Reports Server (NTRS)

Numerical solution of infinite-domain boundary-value problems requires some special techniques that would make the problem available for treatment on the computer. Indeed, the problem must be discretized in a way that the computer operates with only finite amount of information. Therefore, the original infinite-domain formulation must be altered and/or augmented so that on one hand the solution is not changed (or changed slightly) and on the other hand the finite discrete formulation becomes available. One widely used approach to constructing such discretizations consists of truncating the unbounded original domain and then setting the artificial boundary conditions (ABC's) at the newly formed external boundary. The role of the ABC's is to close the truncated problem and at the same time to ensure that the solution found inside the finite computational domain would be maximally close to (in the ideal case, exactly the same as) the corresponding fragment of the original infinite-domain solution. Let us emphasize that the proper treatment of artificial boundaries may have a profound impact on the overall quality and performance of numerical algorithms. The latter statement is corroborated by the numerous computational experiments and especially concerns the area of CFD, in which external problems present a wide class of practically important formulations. In this paper, we review some work that has been done over the recent years on constructing highly accurate nonlocal ABC's for calculation of compressible external flows. The approach is based on implementation of the generalized potentials and pseudodifferential boundary projection operators analogous to those proposed first by Calderon. The difference potentials method (DPM) by Ryaben'kii is used for the effective computation of the generalized potentials and projections. The resulting ABC's clearly outperform the existing methods from the standpoints of accuracy and robustness, in many cases noticeably speed up the multigrid convergence, and at the same time are quite comparable to other methods from the standpoints of geometric universality and simplicity of implementation.

Ryaben 'Kii, Victor S.; Tsynkov, Semyon V.

1997-01-01

219

Wavelet analysis of corneal endothelial electrical potential difference reveals cyclic operation of the secretory mechanism  

NASA Astrophysics Data System (ADS)

The corneal endothelium is a fluid-transporting epithelium. As other similar tissues, it displays an electrical potential of ˜1 mV (aqueous side negative) across the entire layer [transendothelial potential difference (TEPD)]. It appears that this electrical potential is mainly the result of the transport of anions across the cell layer (from stroma to aqueous). There is substantial evidence that the TEPD is related linearly to fluid transport; hence, under proper conditions, its measure could serve as a measure of fluid transport. Furthermore, the TEPD is not steady; instead, it displays a spectrum of frequency components (0-15 Hz) recognized recently using Fourier transforms. Such frequency components appear due to charge-separating (electrogenic) processes mediated by epithelial plasma membrane proteins (both ionic channels and ionic cotransporters). In particular, the endothelial TEPD oscillations of the highest amplitude (1-2 Hz) were linked to the operation of so-called sodium bicarbonate cotransporters. However, no time localization of that activity could be obtained with the Fourier methodology utilized. For that reason we now characterize the TEPD using wavelet analysis with the aim to localize in time the variations in TEPD. We find that the mentioned high-amplitude oscillatory components of the TEPD appear cyclically during the several hours that an endothelial preparation survives in vitro. They have a period of 4.6 ± 0.4 s on average (n=4). The wavelet power value at the peak of such oscillations is 1.5 ± 0.1 mV2 Hz on average (n = 4), and is remarkably narrow in its distribution.

Cacace, V. I.; Montalbetti, N.; Kusnier, C.; Gomez, M. P.; Fischbarg, J.

2011-09-01

220

Benthic ammonia oxidizers differ in community structure and biogeochemical potential across a riverine delta  

PubMed Central

Nitrogen pollution in coastal zones is a widespread issue, particularly in ecosystems with urban or agricultural watersheds. California's Sacramento-San Joaquin Delta, at the landward reaches of San Francisco Bay, is highly impacted by both agricultural runoff and sewage effluent, leading to chronically high nutrient loadings. In particular, the extensive discharge of ammonium into the Sacramento River has altered this ecosystem by vastly increasing ammonium concentrations and thus changing the stoichiometry of inorganic nitrogen stocks, with potential effects throughout the food web. This debate surrounding ammonium inputs highlights the importance of understanding the rates of, and controls on, nitrogen (N) cycling processes across the delta. To date, however, there has been little research examining N biogeochemistry or N-cycling microbial communities in this system. We report the first data on benthic ammonia-oxidizing microbial communities and potential nitrification rates for the Sacramento-San Joaquin Delta, focusing on the functional gene amoA (which codes for the ?-subunit of ammonia monooxygenase). There were stark regional differences in ammonia-oxidizing communities, with ammonia-oxidizing bacteria (AOB) outnumbering ammonia-oxidizing archaea (AOA) only in the ammonium-rich Sacramento River. High potential nitrification rates in the Sacramento River suggested these communities may be capable of oxidizing significant amounts of ammonium, compared to the San Joaquin River and the upper reaches of San Francisco Bay. Gene diversity also showed regional patterns, as well as phylogenetically unique ammonia oxidizers in the Sacramento River. The benthic ammonia oxidizers in this nutrient-rich aquatic ecosystem may be important players in its overall nutrient cycling, and their community structure and biogeochemical function appear related to nutrient loadings. Unraveling the microbial ecology and biogeochemistry of N cycling pathways, including benthic nitrification, is a critical step toward understanding how such ecosystems respond to the changing environmental conditions wrought by human development and climate change. PMID:25620958

Damashek, Julian; Smith, Jason M.; Mosier, Annika C.; Francis, Christopher A.

2015-01-01

221

Nasal potential difference to detect Na+ channel dysfunction in acute lung injury  

PubMed Central

Pulmonary fluid clearance is regulated by the active transport of Na+ and Cl? through respiratory epithelial ion channels. Ion channel dysfunction contributes to the pathogenesis of various pulmonary fluid disorders including high-altitude pulmonary edema (HAPE) and neonatal respiratory distress syndrome (RDS). Nasal potential difference (NPD) measurement allows an in vivo investigation of the functionality of these channels. This technique has been used for the diagnosis of cystic fibrosis, the archetypal respiratory ion channel disorder, for over a quarter of a century. NPD measurements in HAPE and RDS suggest constitutive and acquired dysfunction of respiratory epithelial Na+ channels. Acute lung injury (ALI) is characterized by pulmonary edema due to alveolar epithelial-interstitial-endothelial injury. NPD measurement may enable identification of critically ill ALI patients with a susceptible phenotype of dysfunctional respiratory Na+ channels and allow targeted therapy toward Na+ channel function. PMID:21112943

Mac Sweeney, R.; Fischer, H.

2011-01-01

222

Auditory evoked potentials for the assessment of depth of anaesthesia: different configurations of artefact detection algorithms.  

PubMed

Monitoring the depth of anaesthesia has become an important research topic in the field of biosignal processing. Auditory evoked potentials (AEPs) have been shown to be a promising tool for this purpose. Signals recorded in the noisy environment of an operating theatre are often contaminated by artefacts. Thus, artefact detection and elimination in the underlying electroencephalogram (EEG) are mandatory before AEP extraction. Determination of a suitable artefact detection configuration based on EEG data from a clinical study is described. Artefact detection algorithms and an AEP extraction procedure encompassing the artefact detection results are presented. Different configurations of artefact detection algorithms are evaluated using an AEP verification procedure and support vector machines to determine a suitable configuration for the assessment of depth of anaesthesia using AEPs. PMID:17313341

Luecke, Daniela; Stockmanns, Gudrun; Gallinat, Michael; Kochs, Eberhard F; Schneider, Gerhard

2007-02-01

223

Kinetic and geometric isotope effects originating from different adsorption potential energy surfaces: Cyclohexane on Rh(111)  

NASA Astrophysics Data System (ADS)

Novel isotope effects were observed in desorption kinetics and adsorption geometry of cyclohexane on Rh(111) by the use of infrared reflection absorption spectroscopy, temperature programmed desorption, photoelectron spectroscopy, and spot-profile-analysis low energy electron diffraction. The desorption energy of deuterated cyclohexane (C6D12) is lower than that of C6H12. In addition, the work function change by adsorbed C6D12 is smaller than that by adsorbed C6H12. These results indicate that C6D12 has a shallower adsorption potential than C6H12 (vertical geometric isotope effect). The lateral geometric isotope effect was also observed in the two-dimensional cyclohexane superstructures as a result of the different repulsive interaction between interfacial dipoles. The observed isotope effects should be ascribed to the quantum nature of hydrogen involved in the C-H...metal interaction.

Koitaya, Takanori; Shimizu, Sumera; Mukai, Kozo; Yoshimoto, Shinya; Yoshinobu, Jun

2012-06-01

224

Comparison of triton bound state properties using different separable representations of realistic potentials  

E-print Network

The quality of two different separable expansion methods ({\\sl W} matrix and Ernst-Shakin-Thaler) is investigated. We compare the triton binding energies and components of the triton wave functions obtained in this way with the results of a direct two-dimensional treatment. The Paris, Bonn {\\sl A} and Bonn {\\sl B} potentials are employed as underlying two-body interactions, their total angular momenta being incorporated up to $j \\leq 2$. It is found that the most accurate results based on the Ernst-Shakin-Thaler method agree within 1.5% or better with the two-dimensional calculations, whereas the results for the {\\sl W}-matrix representation are less accurate.

W. Schadow; W. Sandhas; J. Haidenbauer; A. Nogga

1998-10-27

225

Organic nanoparticles from different fuel blends: in vitro toxicity and inflammatory potential.  

PubMed

Despite the well-established link between particulate vehicle emissions and adverse health effects, the biological effects produced by ultrafine particles generated from fuel combustion need to be investigated. The biological impact of nano-sized organic carbon particles in the size range 3-7?nm, obtained from an engine fuelled with a standard diesel and four diesel fuels doped with additives of commercial interest is reported. Our data showed that the number of particles?different nano-sized organic carbon particles induce cytotoxic and proinflammatory effects on the in vitro systems A549 (epithelial cells) and BEAS-2B (bronchial cells). All the fuels tested are able to induce the release of proinflammatory interleukins 8 and 6; moreover, the IC50 values show that the additives can increase the toxic potential of particles 10 times. Further analyses are therefore needed to better define the potential impact of organic ultrafine particles on human health. PMID:25244046

Gualtieri, Maurizio; Capasso, Laura; D'Anna, Andrea; Camatini, Marina

2014-11-01

226

In vitro evaluation of UV opacity potential of Aloe vera L. gel from different germplasms.  

PubMed

In this study, lyophilized crude and methanolic extracts of aloe gel from different germplasms (S24, RM, TN, OR, and RJN) of Aloe vera L. were tested for their ultraviolet (UV) opacity potential. UV absorption profiles, sun protection factor (SPF), and percentage blocking of UVA and UVB were considered to test UV opacity potential. Both the extracts showed UV absorption and followed the same path in the wavelength range of 250-400 nm in all the germplasms. Methanolic extract showed a stronger absorptivity than the crude lyophilized extract. Among the tested germplasms, maximum UV opacity property with a SPF of 9.97% and 79.12% UVB blocking was obtained with RJN, whereas a poor response was evident in TN with a SPF of 1.37% and 28.5% UVB blocking at 4 mg/ml methanolic extract. To our knowledge the present work for the first time documents UV opacity properties of A. vera L. gel and opens up new vistas in Aloe gel characterization. PMID:19034609

Kumar, M Shyam; Datta, P K; Dutta Gupta, S

2009-04-01

227

CFTR involvement in nasal potential differences in mice and pigs studied using a thiazolidinone CFTR inhibitor.  

PubMed

Nasal potential difference (PD) measurements have been used to demonstrate defective CFTR function in cystic fibrosis (CF) and to evaluate potential CF therapies. We used the selective thiazolidinone CFTR inhibitor CFTR(inh)-172 to define the involvement of CFTR in nasal PD changes in mice and pigs. In normal mice infused intranasally with a physiological saline solution containing amiloride, nasal PD was -4.7 +/- 0.7 mV, hyperpolarizing by 15 +/- 1 mV after a low-Cl- solution, and a further 3.9 +/- 0.5 mV after forskolin. CFTR(inh)-172 produced 1.1 +/- 0.9- and 4.3 +/- 0.7-mV depolarizations when added after low Cl- and forskolin, respectively. Systemically administered CFTR(inh)-172 reduced the forskolin-induced hyperpolarization from 4.7 +/- 0.4 to 0.9 +/- 0.1 mV but did not reduce the low Cl(-)-induced hyperpolarization. Nasal PD was -12 +/- 1 mV in CF mice after amiloride, changing by <0.5 mV after low Cl- or forskolin. In pigs, nasal PD was -14 +/- 3 mV after amiloride, hyperpolarizing by 13 +/- 2 mV after low Cl- and a further 9 +/- 1 mV after forskolin. CFTR(inh)-172 and glibenclamide did not affect nasal PD in pigs. Our results suggest that cAMP-dependent nasal PDs in mice primarily involve CFTR-mediated Cl- conductance, whereas cAMP-independent PDs are produced by a different, but CFTR-dependent, Cl- channel. In pigs, CFTR may not be responsible for Cl- channel-dependent nasal PDs. These results have important implications for interpreting nasal PDs in terms of CFTR function in animal models of CFTR activation and inhibition. PMID:15246976

Salinas, Danieli B; Pedemonte, Nicoletta; Muanprasat, Chatchai; Finkbeiner, Walter F; Nielson, Dennis W; Verkman, A S

2004-11-01

228

Noise Reduction Potential of Large, Over-the-Wing Mounted, Advanced Turbofan Engines  

NASA Technical Reports Server (NTRS)

As we look to the future, increasingly stringent civilian aviation noise regulations will require the design and manufacture of extremely quiet commercial aircraft. Indeed, the noise goal for NASA's Aeronautics Enterprise calls for technologies that will help to provide a 20 EPNdB reduction relative to today's levels by the year 2022. Further, the large fan diameters of modem, increasingly higher bypass ratio engines pose a significant packaging and aircraft installation challenge. One design approach that addresses both of these challenges is to mount the engines above the wing. In addition to allowing the performance trend towards large, ultra high bypass ratio cycles to continue, this over-the-wing design is believed to offer noise shielding benefits to observers on the ground. This paper describes the analytical certification noise predictions of a notional, long haul, commercial quadjet transport with advanced, high bypass engines mounted above the wing.

Berton, Jeffrey J.

2000-01-01

229

Potential impacts of the Deepwater Horizon oil spill on large pelagic fishes  

NASA Astrophysics Data System (ADS)

Biogeographical analyses provide insights on how the Deepwater Horizon oil spill impacted large pelagic fishes. We georeferenced historical ichthyoplankton surveys and published literature to map the spawning and larval areas of bluefin tuna, swordfish, blue marlin and whale shark sightings in the Gulf of Mexico with daily satellite-derived images detecting surface oil. The oil spill covered critical areas used by large pelagic fishes. Surface oil was detected in 100% of the northernmost whale shark sightings, in 32.8 % of the bluefin tuna spawning area and 38 % of the blue marlin larval area. No surface oil was detected in the swordfish spawning and larval area. Our study likely underestimates the extend of the oil spill due to satellite sensors detecting only the upper euphotic zone and the use of dispersants altering crude oil density, but provides a previously unknown spatio-temporal analysis.

Frias-Torres, Sarrah; Bostater, Charles R., Jr.

2011-11-01

230

Chemistry and potential mutagenicity of humic substances in waters from different watersheds in Britain and Ireland  

USGS Publications Warehouse

Humic substances are amorphous organic macromolecules responsible for the hue of natural waters. They are also known to be precursors of mutagens formed on chlorination prior to distribution of drinking water. In this study humic substances from the waters of primary streams, from major rivers, and from reservoirs were isolated and fractionated into humic acids (HA), fulvic acids (FA) and XAD-4 acids using columns of XAD-8 and of XAD-4 resins in tandem, and the fractions from the different sources were chlorinated and assayed for mutagenicity. CPMAS 13C NMR spectroscopy showed marked differences in compositions not only between HA, FA, and XAD-4 acids from the same water samples, but also between the same fractions from water samples from different watersheds. There were found to be strong similarities between the fractions from watersheds which had closely related soil types. Aromaticity was greatest in HAs, and lowest in XAD-4 acids, and carboxyl contents and aliphatic character were greatest in the XAD-4 acids. Carbon content decreased in the order HA > FA > XAD-4 acids, and amino acids and neutral sugars contents decreased in the order HA > XAD-4 > FA. Titration data complemented aspects of the NMR data, demonstrating that carboxyl content decreased in the order XAD-4 acids > FA > HA, and indicated that phenolic character was highest in HAs and lowest in the XAD-4 acids. All samples tested gave rise to bacterial mutagens on chlorination. Although the mutagenicities were of the same order of magnitude for the chlorinated humic samples from the different sources, the samples which showed the greatest number of revertant bacterial colonies were from the Thames and Trent, large rivers with humic materials from diverse environments, and relatively high in amino acid contents.

Watt, B.E.; Malcolm, R.L.; Hayes, M.H.B.; Clark, N.W.E.; Chipman, J.K.

1996-01-01

231

Difference of Diagnostic Rates and Analytical Methods in the Test Positions of Vestibular Evoked Myogenic Potentials  

PubMed Central

Objective To compare the differences of diagnostic rates, of the two widely used test positions, in measuring vestibular evoked myogenic potentials (VEMP) and selecting the most appropriate analytical method for diagnostic criteria for the patients with vertigo. Methods Thirty-two patients with vertigo were tested in two comparative testing positions: turning the head to the opposite side of the evaluating side and bowing while in seated position, and bowing while in supine positions. Abnormalities were determined by prolonged latency of p13 or n23, shortening of the interpeak latency, and absence of VEMP formation. Results Using the three criteria above for determining abnormalities, both the seated and supine positions showed no significant differences in diagnostic rates, however, the concordance correlation of the two positions was low. When using only the prolonged latency of p13 or n23 in the two positions, diagnostic rates were not significantly different and their concordance correlation was high. On the other hand, using only the shortened interpeak latency in both positions showed no significant difference of diagnostic rates, and the degree of agreement between two positions was low. Conclusion Bowing while in seated position with the head turned in the opposite direction to the area being evaluated is found to be the best VEMP test position due to the consistent level of sternocleidomastoid muscle tension and the high level of compliance. Also, among other diagnostic analysis methods, using prolonged latency of p13 or n23 as the criterion is found to be the most appropriate method of analysis for the VEMP test. PMID:24855617

Park, Jeong Mee; Yong, Sang Yeol; Kim, Jong Heon; Kim, Hee; Park, Sang-Yoo

2014-01-01

232

Simulated environmental criticalities affect transglutaminase of Malus and Corylus pollens having different allergenic potential.  

PubMed

Increases in temperature and air pollution influence pollen allergenicity, which is responsible for the dramatic raise in respiratory allergies. To clarify possible underlying mechanisms, an anemophilous pollen (hazel, Corylus avellana), known to be allergenic, and an entomophilous one (apple, Malus domestica), the allergenicity of which was not known, were analysed. The presence also in apple pollen of known fruit allergens and their immunorecognition by serum of an allergic patient were preliminary ascertained, resulting also apple pollen potentially allergenic. Pollens were subjected to simulated stressful conditions, provided by changes in temperature, humidity, and copper and acid rain pollution. In the two pollens exposed to environmental criticalities, viability and germination were negatively affected and different transglutaminase (TGase) gel bands were differently immunodetected with the polyclonal antibody AtPng1p. The enzyme activity increased under stressful treatments and, along with its products, was found to be released outside the pollen with externalisation of TGase being predominant in C. avellana, whose grain presents a different cell wall composition with respect to that of M. domestica. A recombinant plant TGase (AtPng1p) stimulated the secreted phospholipase A(2) (sPLA(2)) activity, that in vivo is present in human mucosa and is involved in inflammation. Similarly, stressed pollen, hazel pollen being the most efficient, stimulated to very different extent sPLA(2) activity and putrescine conjugation to sPLA(2). We propose that externalised pollen TGase could be one of the mediators of pollen allergenicity, especially under environmental stress induced by climate changes. PMID:21847612

Iorio, Rosa Anna; Di Sandro, Alessia; Paris, Roberta; Pagliarani, Giulia; Tartarini, Stefano; Ricci, Giampaolo; Serafini-Fracassini, Donatella; Verderio, Elisabetta; Del Duca, Stefano

2012-02-01

233

Dispersal of large branchiopod cysts: Potential movement by wind from potholes on the Colorado Plateau  

USGS Publications Warehouse

Wind is suspected to be a primary dispersal mechanism for large branchiopod cysts on the Colorado Plateau. We used a wind tunnel to investigate wind velocities capable of moving pothole sediment and cysts from intact and disturbed surfaces. Material moved in the wind tunnel was trapped in filters; cysts were separated from sediment and counted. Undisturbed sediment moved at velocities as low as 5.9 m s-1 (12.3 miles h-1). A single all-terrain vehicle (ATV) track increased the sediment mass collected 10-fold, with particles moving at a wind velocity of only 4.2 m s-1 (8.7 miles h-1). Cysts were recovered from every wind tunnel trial. Measured wind velocities are representative of low-wind speeds measured near Moab, Utah. Wind can move large numbers of cysts to and from potholes on the Colorado Plateau. Our results indicate that large branchiopod cysts move across pothole basins at low-wind speeds; additional work is needed to establish velocities at which cysts move between potholes. ?? 2007 Springer Science+Business Media B.V.

Graham, T.B.; Wirth, D.

2008-01-01

234

Large change in the predicted number of small halos due to a small amplitude oscillating inflaton potential  

SciTech Connect

A smooth inflaton potential is generally assumed when calculating the primordial power spectrum, implicitly assuming that a very small oscillation in the inflaton potential creates a negligible change in the predicted halo mass function. We show that this is not true. We find that a small oscillating perturbation in the inflaton potential in the slow-roll regime can alter significantly the predicted number of small halos. A class of models derived from supergravity theories gives rise to inflaton potentials with a large number of steps and many trans-Planckian effects may generate oscillations in the primordial power spectrum. The potentials we study are the simple quadratic (chaotic inflation) potential with superimposed small oscillations for small field values. Without leaving the slow-roll regime, we find that for a wide choice of parameters, the predicted number of halos change appreciably. For the oscillations beginning in the 10{sup 7}-10{sup 8}M{sub {center_dot}}range, for example, we find that only a 5% change in the amplitude of the chaotic potential causes a 50% suppression of the number of halos for masses between 10{sup 7}-10{sup 8}M{sub {center_dot}}and an increase in the number of halos for masses <10{sup 6}M{sub {center_dot}}by factors {approx}15-50. We suggest that this might be a solution to the problem of the lack of observed dwarf galaxies in the range 10{sup 7}-10{sup 8}M{sub {center_dot}.} This might also be a solution to the reionization problem where a very large number of Population III stars in low mass halos are required.

Rodrigues, Luiz Felippe S.; Opher, Reuven [Instituto de Astronomia Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, CEP 05508-900, Sao Paulo, SP (Brazil)

2010-07-15

235

Differences in F36VMpl-Based in Vivo Selection Among Large Animal Models  

Microsoft Academic Search

Animal models are indispensable tools for understanding physiological and pathological processes, as well as for developing new therapies. Ultimately, the results of animal experimentation must provide information that can guide the development of therapeutic approaches in humans. Significant differences have been reported comparing a gene therapy approach between different animal models. However, little information exists describing differences among the available

Robert E. Richard; R. Angelo De Claro; James Yan; Sylvia Chien; Horst von Recum; Julia Morris; Hans-Peter Kiem; David C. Dalgarno; Shelly Heimfeld; Tim Clackson; Robert Andrews; C. Anthony Blau

2004-01-01

236

Assessing the impact of different satellite retrieval methods on forecast available potential energy  

NASA Technical Reports Server (NTRS)

The effects of the inclusion of satellite temperature retrieval data, and of different satellite retrieval methods, on forecasts made with the NASA Goddard Laboratory for Atmospheres (GLA) fourth-order model were investigated using, as the parameter, the available potential energy (APE) in its isentropic form. Calculation of the APE were used to study the differences in the forecast sets both globally and in the Northern Hemisphere during 72-h forecast period. The analysis data sets used for the forecasts included one containing the NESDIS TIROS-N retrievals, the GLA retrievals using the physical inversion method, and a third, which did not contain satellite data, used as a control; two data sets, with and without satellite data, were used for verification. For all three data sets, the Northern Hemisphere values for the total APE showed an increase throughout the forecast period, mostly due to an increase in the zonal component, in contrast to the verification sets, which showed a steady level of total APE.

Whittaker, Linda M.; Horn, Lyle H.

1990-01-01

237

Multidimensional scaling of schematically represented faces based on dissimilarity estimates and evoked potentials of differences amplitudes.  

PubMed

This study researches the input of the cerebral occipital and temporal cortex in the analysis of facial configuration and expressive characteristics. Analysis is based on the construction of a spherical model for the differentiation of schematically presented faces with quantitatively altering curvature of the mouth and brows. The model is designed using the method of multidimensional scaling of the dissimilarity judgments between stimuli (faces) and the amplitude of evoked potentials of differences (EPD) between abrupt stimulus changes recorded from the occipital and posterior temporal cortex. Analysis of the structure of the spherical model of facial differentiation depending on the electrode site and the latency of the EPD component within the duration of 120-240 ms has demonstrated that the activity of the occipital and posterior temporal cortex of the right hemisphere is associated with the emotional characteristics of the presented face, whereas facial configuration is reflected in the activation of both posterior temporal cortex and the occipital cortex of the left hemisphere. At all electrode sites maximum information of the emotional expression and configuration is represented in inter-peak amplitude P120-N180. With increasing latency there is increased distortion of the structure of differences in the spherical model of schematically presented faces, which is interpreted as an attenuation of electrical activity associated with the analysis of the emotional expression, which occurs more rapidly than configuration analysis. PMID:16255381

Izmailov, Chingiz A; Sokolov, Evgeni N; Korshunova, Svetlana G

2005-11-01

238

Potential benefits of a ceramic thermal barrier coating on large power generation gas turbine  

NASA Technical Reports Server (NTRS)

Thermal barrier coating design option offers benefit in terms of reduced electricity costs when used in utility gas turbines. Options considered include: increased firing temperature, increased component life, reduced cooling air requirements, and increased corrosion resistance (resulting in increased tolerance for dirty fuels). Performance and cost data were obtained. Simple, recuperated and combined cycle applications were considered, and distillate and residual fuels were assumed. The results indicate that thermal barrier coatings could produce large electricity cost savings if these coatings permit turbine operation with residual fuels at distillate-rated firing temperatures. The results also show that increased turbine inlet temperature can result in substantial savings in fuel and capital costs.

Clark, J. S.; Nainiger, J. J.

1977-01-01

239

NREL Confirms Large Potential for Grid Integration of Wind, Solar Power (Fact Sheet)  

SciTech Connect

To fully harvest the nation's bountiful wind and solar resources, it is critical to know how much electrical power from these renewable resources could be integrated reliably into the grid. To inform the discussion about the potential of such variable sources, the National Renewable Energy Laboratory (NREL) launched two key regional studies, examining the east and west sections of the U.S. power grid. The studies show that it is technically possible for U.S. power systems to integrate 20%-35% renewable electricity if infrastructure and operational improvements can be made.

Not Available

2011-10-01

240

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

PubMed

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. PMID:25615683

Rashev, Svetoslav; Moule, David C

2015-04-01

241

Broadband Photometry of the Large Potentially Hazardous Asteroid 138095 (2000 DK79)  

NASA Astrophysics Data System (ADS)

The Near-Earth Asteroid (NEA)138095 (2000 DK79) was discovered by the LINEAR Sky Survey on February 26, 2010 (MPEC 2000-E42). With a Minimum Orbit Intersection Distance (MOID) of 0.049 AU and an expected diameter between 1.8 km and 3 km, this object has been designated as a Potentially Hazardous Asteroid (PHA) by the Minor Planet Center. We obtained two partial nights of broadband Bessel BVRI photometry at the JPL Table Mountain 0.6-m telescope (TMO) on November 16 and 17, 2013, as summarized in Table 1.

Hicks, M.; Ebelhar, S.

2013-11-01

242

Transcriptome profile at different physiological stages reveals potential mode for curly fleece in Chinese tan sheep.  

PubMed

Tan sheep (Ovis aries), a Chinese indigenous breed, has special curly fleece after birth, especially at one month old. However, this unique phenotype disappears gradually with age and the underlying reasons of trait evolvement are still unknown. In this study, skin transcriptome data was used to study this issue. In total 51,215 transcripts including described transcripts and transfrags were identified. Pathway analysis of the top 100 most highly expressed transcripts, which included TCHH and keratin gene family members, such as KRT25, KRT5, KRT71, KRT14 and others, showed pathways known to be relevant to hair/fleece development and function. Six hundred differentially expressed (DE) transcripts were detected at two different physiological ages (one-month-old with curly fleece and 48-month-old without curly fleece) and were categorized into three major functional groups: cellular component, molecular function, and biological process. The top six functional categories included cell, cell part, cellular process, binding, intracellular, metabolic process. The detected differentially expressed genes were particularly involved in signal, signal peptide, disulfide bond, glycoprotein and secreted terms, respectively. Further splicing isoform analysis showed that the metallothionein 3 isoform was up-regulated in Tan lamb skin, indicating that it may be related to the conformation of curly fleece in Chinese Tan lamb. The hair-related important differentially expressed genes (SPINK4, FGF21, ESR?, EphA3, NTNG1 and GPR110) were confirmed by qPCR analysis. We deduced that the differences existed in expressed transcripts, splice isoforms and GO categories between the two different physiological stages, which might constitute the major reasons for explaining the trait evolvement of curly fleece in Chinese Tan sheep. This study provides some clues for elucidating the molecular mechanism of fleece change with age in Chinese Tan sheep, as well as supplying some potential values for understanding human hair disorder and texture changes. PMID:23990983

Kang, Xiaolong; Liu, Gang; Liu, Yufang; Xu, Qinqin; Zhang, Ming; Fang, Meiying

2013-01-01

243

Screening candidate metastasis-associated genes in three-dimensional HCC spheroids with different metastasis potential  

PubMed Central

Purpose: Previously, we have established a tissue-like HCC spheroid which better mirrors the biological features of tumorigenesis and metastasis. This study was to find out metastasis-associated genes between two 3D HCC spheroids with different metastasis potential using comparative PCR arrays. Materials and Methods: Two HCC spheroids derived from high-metastatic MHCC97H cells and low-metastatic Hep3B cells were formed respectively in a rotating wall vessel bioreactor after 3D culture for 15 days. The candidate metastasis-associated genes related to cell adhesion, matrix secretion and invasion in HCC spheroids were screened by RT² profiler PCR arrays. The expression patterns of several differentially-expressed genes were further confirmed by real-time RT-PCR. Results: Total of 123 differential expression genes (fold-change >2) were found between two HCC spheroids, including 70 up-regulated genes (VCAM-1, IL-1?, CD44, tenascin C, SPP1, fibronectin, MMP-2, MMP-7, etc) and 53 down-regulated genes (E-cadherin, CTNND2, etc) in the high-metastatic spheroid. Function classification showed that the number of up-regulated genes related to adhesion molecules mediating cell-matrix interactions and matrix secretion was significantly higher in high-metastatic spheroid than that in low-metastatic spheroid. In contrast, the expressions of adhesion molecules maintaining homotypic tumor cell adhesion were decreased in metastatic spheroid as compared with that in low-metastatic spheroid. In addition, the expression pattern of seven selected genes associated with tumor metastasis measured by real-time RT-PCR were consistent with results of PCR arrays. Conclusions: Obvious differences between two HCC spheroids in gene expression patterns of adhesion molecules, matrix secretion, invasion and other molecules may determine the different metastatic characteristics and malignant phenotype of HCC spheroid. PMID:24966965

Chen, Rongxin; Dong, Yinying; Xie, Xiaoying; Chen, Jie; Gao, Dongmei; Liu, Yinkun; Ren, Zhenggang; Cui, Jiefeng

2014-01-01

244

Reactive power optimization with different objectives in large power systems including HVDC systems and FACTS devices  

Microsoft Academic Search

Present day power systems are growing in size and complexity of operation with inter connections to neighboring systems, introduction of large generating units, EHV 400\\/765 kV AC transmission systems, HVDC systems and more sophisticated control devices such as FACTS. For planning and operational studies, it requires suitable modeling of all components in the power system, as the number of HVDC

D. Thukaram; S. Lakpathi; K. Ravishankar; S. Surendra

2009-01-01

245

Large vocabulary Mandarin speech recognition with different approaches in modeling tones  

Microsoft Academic Search

Large vocabulary continuous Mandarin speech recognition has been an important problem for speech recognition researchers for several reasons (1), (3). First of all, it is a tonal language that requires special treatment for the modeling of tones. There are five tones in Mandarin which are necessary to disambiguate between confusable words. Secondly, the difficulty of entering Chinese by keyboard presents

Eric Chang; Jian-Lai Zhou; Shuo Di; Chao Huang; Kai-Fu Lee

2000-01-01

246

Differences in rural and urban driver-injury severities in accidents involving large-trucks: An exploratory analysis  

Microsoft Academic Search

This study explores the differences between urban and rural driver injuries (both passenger-vehicle and large-truck driver injuries) in accidents that involve large trucks (in excess of 10,000 pounds). Using 4 years of California accident data, and considering four driver-injury severity categories (no injury, complaint of pain, visible injury, and severe\\/fatal injury), a multinomial logit analysis of the data was conducted.

Ahmad Khorashadi; Debbie Niemeier; Venky Shankar; Fred Mannering

2005-01-01

247

Plant community response to loss of large herbivores differs between North American and South African savanna grasslands.  

PubMed

Herbivory and fire shape plant community structure in grass-dominated ecosystems, but these disturbance regimes are being altered around the world. To assess the consequences of such alterations, we excluded large herbivores for seven years from mesic savanna grasslands sites burned at different frequencies in North America (Konza Prairie Biological Station, Kansas, USA) and South Africa (Kruger National Park). We hypothesized that the removal of a single grass-feeding herbivore from Konza would decrease plant community richness and shift community composition due to increased dominance by grasses. Similarly, we expected grass dominance to increase at Kruger when removing large herbivores, but because large herbivores are more diverse, targeting both grasses and forbs, at this study site, the changes due to herbivore removal would be muted. After seven years of large-herbivore exclusion, richness strongly decreased and community composition changed at Konza, whereas little change was evident at Kruger. We found that this divergence in response was largely due to differences in the traits and numbers of dominant grasses between the study sites rather than the predicted differences in herbivore assemblages. Thus, the diversity of large herbivores lost may be less important in determining plant community dynamics than the functional traits of the grasses that dominate mesic, disturbance-maintained savanna grasslands. PMID:24933802

Koerner, Sally E; Burkepile, Deron E; Fynn, Richard W S; Burns, Catherine E; Eby, Stephanie; Govender, Navashni; Hagenah, Nicole; Matchett, Katherine J; Thompson, Dave I; Wilcox, Kevin R; Collins, Scott L; Kirkman, Kevin P; Knapp, Alan K; Smith, Melinda D

2014-04-01

248

Sediment pollution in the Elbe estuary and its potential toxicity at different trophic levels.  

PubMed

Sediment contamination is one of the most pressing environmental problems in estuaries of industrialized countries and is of special interest to water managers involved in waterway maintenance dredging. In the present study, eight heavy metals (As, Pb, Cd, Cr, Cu, Ni, Hg, and Zn) and 41 organic compounds (pentachlorbenzol (PeCB), hexachlorbenzol (HCB), 7 polychlorinated biphenyls (PCBs), the hexachlorocyclohexanes ?-HCH, ?-HCH, ?-HCH, 6 dichlorodiphenyltrichloroethane isomers, organochlorine styrene (OCS), octachloronaphthalene (OCN), 15 polycyclic aromatic hydrocarbons (PAHs), and 6 organotin (OT) compounds) were analyzed in surface sediments at 36 sites in the Elbe estuary in 2006. Correlation analysis showed a general decrease in sediment contaminant concentrations from the stations near the port of Hamburg towards the open sea. This decrease was significant (Spearman's rank correlation, p<0.05) with most pollutants. In addition, cluster analysis identified five groups of sites with different sediment contaminant patterns within the Elbe estuary. Worst case toxic risks stemming from sediment-bound organic pollutants were predicted using the Toxic Unit approach, based on estimated pore-water concentrations under equilibrium conditions and acute LC50 values for three standard test organisms of the trophic levels of fish, invertebrates, and algae. The estimated sediment toxicity was significantly higher in the inner part (river-km 630 to 660) compared with the estuarine mouth. Moreover, potential toxicity of organic pollutants estimated for invertebrates and for fish exceeded acute-based effect thresholds at 30 and 24 stations, respectively. Chronic effects for invertebrates are expected at all sites investigated. We conclude that sediment pollution and related potential toxicity in the Elbe estuary may have more influence on the benthos fauna than expected to date. PMID:23428749

Wetzel, Markus A; Wahrendorf, Dierk-Steffen; von der Ohe, Peter C

2013-04-01

249

Denitrification potential of different land-use types in an agricultural watershed, lower Mississippi valley  

USGS Publications Warehouse

Expansion of agricultural land and excessive nitrogen (N) fertilizer use in the Mississippi River watershed has resulted in a three-fold increase in the nitrate load of the river since the early 1950s. One way to reduce this nitrate load is to restore wetlands at suitable locations between croplands and receiving waters to remove run-off nitrate through denitrification. This research investigated denitrification potential (DP) of different land uses and its controlling factors in an agricultural watershed in the lower Mississippi valley (LMV) to help identify sites with high DP for reducing run-off nitrate. Soil samples collected from seven land-use types of an agricultural watershed during spring, summer, fall and winter were incubated in the laboratory for DP determination. Low-elevation clay soils in wetlands exhibited 6.3 and 2.5 times greater DP compared to high-elevation silt loam and low-elevation clay soils in croplands, respectively. DP of vegetated-ditches was 1.3 and 4.2 times that of un-vegetated ditches and cultivated soils, respectively. Soil carbon and nitrogen availability, bulk density, and soil moisture significantly affected DP. These factors were significantly influenced in turn by landscape position and land-use type of the watershed. It is evident from these results that low-elevation, fine-textured soils under natural wetlands are the best locations for mediating nitrate loss from agricultural watersheds in the LMV. Landscape position and land-use types can be used as indices for the assessment/modeling of denitrification potential and identification of sites for restoration for nitrate removal in agricultural watersheds. ?? 2006 Elsevier B.V. All rights reserved.

Ullah, S.; Faulkner, S.P.

2006-01-01

250

Sex Differences in Autism Spectrum Disorder: Evidence from a Large Sample of Children and Adolescents  

ERIC Educational Resources Information Center

Sex differences have been found amongst toddlers and young children with autism spectrum disorder (ASD). We investigated the presence and stability of these ASD sex differences throughout childhood and adolescence. Participants (N = 325, 52 females; aged 3-18 years) consecutively received an ASD diagnosis at a clinic for assessing high-functioning…

Mandy, William; Chilvers, Rebecca; Chowdhury, Uttom; Salter, Gemma; Seigal, Anna; Skuse, David

2012-01-01

251

Hydrodynamic modeling of juvenile mussel dispersal in a large river: The potential effects of bed shear stress and other parameters  

USGS Publications Warehouse

Because unionid mussels have a parasitic larval stage, they are able to disperse upstream and downstream as larvae while attached to their host fish and with flow as juveniles after excystment from the host. Understanding unionid population ecology requires knowledge of the processes that affect juvenile dispersal prior to establishment. We examined presettlement (transport and dispersion with flow) and early postsettlement (bed shear stress) hydraulic processes as negative censoring mechanisms. Our approach was to model dispersal using particle tracking through a 3-dimensional flow field output from hydrodynamic models of a reach of the Upper Mississippi River. We tested the potential effects of bed shear stress (??b) at 5 flow rates on juvenile mussel dispersal and quantified the magnitude of these effects as a function of flow rate. We explored the reach-scale relationships of Froude number (Fr), water depth (H), local bed slope (S), and unit stream power (QS) with the likelihood of juvenile settling (??). We ran multiple dispersal simulations at each flow rate to estimate ??, the parameter of a Poisson distribution, from the number of juveniles settling in each grid cell, and calculated dispersal distances. Virtual juveniles that settled in areas of the river where b > critical shear stress (c) were resuspended in the flow and transported further downstream, so we ran simulations at 3 different conditions for ??c (??c = ??? no resuspension, 0.1, and 0.05 N/m2). Differences in virtual juvenile dispersal distance were significantly dependent upon c and flow rate, and effects of b on settling distribution were dependent upon c. Most simulations resulted in positive correlations between ?? and ??b, results suggesting that during early postsettlement, ??b might be the primary determinant of juvenile settling distribution. Negative correlations between ?? and ??b occurred in some simulations, a result suggesting that physical or biological presettlement processes might determine juvenile settling distributions. Field data are needed to test these hypotheses. Results support the idea that flow patterns and b can act as negative censoring mechanisms controlling settling distributions. Furthermore, a river reach probably has a quantifiable threshold range of flow rates. Above the upper threshold, ??b probably is the primary determinant of juvenile settling distribution. Relationships of ?? with H, Fr, S, and QS were relatively weak. Important physical processes that affect dispersal probably are not captured by approximations based on large-scale hydraulic parameters, such as Fr and H. ?? 2010 The North American Benthological Society.

Daraio, J.A.; Weber, L.J.; Newton, T.J.

2010-01-01

252

Estimating Demand Response Market Potential Among Large Commercialand Industrial Customers:A Scoping Study  

SciTech Connect

Demand response is increasingly recognized as an essentialingredient to well functioning electricity markets. This growingconsensus was formalized in the Energy Policy Act of 2005 (EPACT), whichestablished demand response as an official policy of the U.S. government,and directed states (and their electric utilities) to considerimplementing demand response, with a particular focus on "price-based"mechanisms. The resulting deliberations, along with a variety of stateand regional demand response initiatives, are raising important policyquestions: for example, How much demand response is enough? How much isavailable? From what sources? At what cost? The purpose of this scopingstudy is to examine analytical techniques and data sources to supportdemand response market assessments that can, in turn, answer the secondand third of these questions. We focus on demand response for large(>350 kW), commercial and industrial (C&I) customers, althoughmany of the concepts could equally be applied to similar programs andtariffs for small commercial and residential customers.

Goldman, Charles; Hopper, Nicole; Bharvirkar, Ranjit; Neenan,Bernie; Cappers, Peter

2007-01-01

253

Broadband Photometry of 2012 LZ1: A Large, Dark Potentially Hazardous Asteroid  

NASA Astrophysics Data System (ADS)

2012 LZ1 was discovered on June 10, 2012 by R. McNaught (MPEC 2012-L30). The NEO passed within 0.0364 AU of the Earth on June 14.96 2012 and has been designated as a Potentially Hazardous Asteroid (PHA) by the IAU Minor Planet Center. We obtained 5 nights of time-resolved photometry at the JPL Table Mountain Observatory (TMO) 0.6-m telescope, as summarized in Table 1. Due to a high rate of motion and background star density it was necessary to minimize contamination by creating a running sky background template using adjacent frames and subtracting this template from each R-band frame, as shown in Figure 1.

Hicks, M.; Smythe, W.; Davtyan, T.; Dombroski, D.; Strojia, C.; Teague, S.

2012-07-01

254

Recruitment potential of two perennial grasses with different growth forms at a semiarid-arid transition zone  

Microsoft Academic Search

The objective of this study was to quantify differences in recruitment potential (seed production, seed presence in the soil) for two congeneric perennial grasses (Bouteloua gracilis, Bouteloua eriopoda (Poaceae)) that dominate adjacent arid and semiarid grassland biomes. It was hypothesized that these species have different recruitment strategies at the biome transition zone that are related to differences in their growth

DEBRA P. C. PETERS

2002-01-01

255

Frequency of subthreshold oscillations at different membrane potential voltages in neurons at different anatomical positions on the dorsoventral axis in the rat medial entorhinal cortex.  

PubMed

Neurons from layer II of the medial entorhinal cortex show subthreshold membrane potential oscillations (SMPOs) which could contribute to theta-rhythm generation in the entorhinal cortex and to generation of grid cell firing patterns. However, it is unclear whether single neurons have a fixed unique oscillation frequency or whether their frequency varies depending on the mean membrane potential in a cell. We therefore examined the frequency of SMPOs at different membrane potentials in layer II stellate-like cells of the rat medial entorhinal cortex in vitro. Using whole-cell patch recordings, we found that the fluctuations in membrane potential show a broad band of low power frequencies near resting potential that transition to more narrowband oscillation frequencies with depolarization. The transition from broadband to narrowband frequencies depends on the location of the neuron along the dorsoventral axis in the entorhinal cortex, with dorsal neurons transitioning to higher-frequency oscillations relative to ventral neurons transitioning to lower-frequency oscillations. Once SMPOs showed a narrowband frequency, systematic frequency changes were not observed with further depolarization. Using a Hodgkin-Huxley-style model of membrane currents, we show that differences in the influence of depolarization on the frequency of SMPOs at different dorsal to ventral positions could arise from differences in the properties of the h current. The properties of frequency changes in this data are important for evaluating models of the generation of grid cell firing fields with different spacings along the dorsal-to-ventral axis of medial entorhinal cortex. PMID:21880929

Yoshida, Motoharu; Giocomo, Lisa M; Boardman, Ian; Hasselmo, Michael E

2011-08-31

256

Phenomenon of labyrinth weal with Low static pressure difference and large clearance  

Microsoft Academic Search

Absract  The low pressure axial flow fans with an outer ring, used for cooling automobile radiators, have a significantly large tip\\u000a clearance between the ring tip and the fan shroud. It has been found that the turbulent reverse flow, or leakage flow, which\\u000a occurs at the tip clearance, greatly affects the fan performance and noise level. Therefore, in order to improve

K. Kimura; H. Ohta; K. Aoki

2003-01-01

257

Large-scale synthesis, characterization and microwave absorption properties of carbon nanotubes of different helicities  

NASA Astrophysics Data System (ADS)

Carbon nanotubes of high helicity (H-HCNTs, Sample A) have been synthesized in large-scale by pyrolysis of acetylene at 450 °C over Fe nanoparticles derived from coprecipitation/hydrogen reduction method. With controlled introduction of hydrogen during acetylene pyrolysis, CNTs of low helicity (L-HCNTs, Sample B) and worm-like CNTs (Sample C) were obtained in large quantities. The yields of the CNTs products are high, especially that of H-HCNTs (ca. 7474%). The complex permittivity and permeability of Composites A, B, and C that contain Samples A, B and C (30 wt%) were measured in the 2-18 GHz frequency range. Good absorption of electromagnetic wave (reflection loss<-20 dB) was observed in the 7.18-10.68 and 7.5-10.7 GHz range over Composites B and C (2.0-3.0 mm thickness), respectively. Thus, through the suggested route, CNTs can be produced easily and selectively in large quantities. The lightweight materials can be utilized for microwave absorption.

Qi, Xiaosi; Yang, Yi; Zhong, Wei; Deng, Yu; Au, Chaktong; Du, Youwei

2009-10-01

258

Adult and cord blood endothelial progenitor cells have different gene expression profiles and immunogenic potential  

PubMed Central

Background Endothelial colony-forming cells (ECFC) are endowed with vascular regenerative ability in vivo and in vitro. In this study we compared the genotypic profile and the immunogenic potential of adult and cord blood ECFC, in order to explore the feasibility of using them as a cell therapy product. Materials and methods ECFC were obtained from cord blood samples not suitable for haematopoietic stem cell transplantation and from adult healthy blood donors after informed consent. Genotypes were analysed by commercially available microarray assays and results were confirmed by real-time polymerase chain reaction analysis. HLA antigen expression was evaluated by flow-cytometry. Immunogenic capacity was investigated by evaluating the activation of allogeneic lymphocytes and monocytes in co-cultures with ECFC. Results Microarray assays revealed that the genetic profile of cord blood and adult ECFC differed in about 20% of examined genes. We found that cord blood ECFC were characterised by lower pro-inflammatory and pro-thrombotic gene expression as compared to adult ECFC. Furthermore, whereas cord blood and adult ECFCs expressed similar amount of HLA molecules both at baseline and after incubation with ?-interferon, cord blood ECFC elicited a weaker expression of pro-inflammatory cytokine genes. Finally, we observed no differences in the amount of HLA antigens expressed among cord blood ECFC, adult ECFC and mesenchymal cells. Conclusions Our observations suggest that cord blood ECFC have a lower pro-inflammatory and pro-thrombotic profile than adult ECFC. These preliminary data offer level-headed evidence to use cord blood ECFC as a cell therapy product in vascular diseases. PMID:23867184

Nuzzolo, Eugenia R.; Capodimonti, Sara; Martini, Maurizio; Iachininoto, Maria G.; Bianchi, Maria; Cocomazzi, Alessandra; Zini, Gina; Leone, Giuseppe; Larocca, Luigi M.; Teofili, Luciana

2014-01-01

259

Utilizing Focus Groups with Potential Participants and Their Parents: An Approach to Inform Study Design in a Large Clinical Trial  

PubMed Central

Background In the recent literature, there has been some evidence that exposure of children to anesthetic procedures during the first two years of life may impair cognitive function and learning in later life. We planned a clinical study to quantify this risk, a study involving testing 1,000 children for neurodevelopmental deficits. As a part of this planning, we conducted focus groups involving potential participants and their parents to elicit information regarding three issues: communications with the community and potential participants, recruitment and consent processes, and the return of neurodevelopmental testing results. Methods Three focus groups were conducted with the parents of potential participants and one focus group was conducted with an 18-19 year old group; each group consisted of 6-10 participants. The moderated discussions had questions about recruitment, consenting issues, and expectations from the study about return of both overall trial findings and individual research test results. Results The focus group data gave us an insight on potential participants’ views on recruitment, consenting, communications about the study, and expectations about return of both overall trial findings and individual research test results. The concerns expressed were largely addressable. In addition, the concern we had about some parents enrolling their children in the study solely for the sake of getting their child's cognitive function results was dispelled. Conclusions We found that the individuals participating in our focus groups were generally enthusiastic about the large clinical study and could see the value in answering the study question. The data from the focus groups were used to inform changes to the recruitment and consent process. Focus group input was also instrumental in affirming the study design regarding return of results. Our experience suggests that the approach we used may serve as a model for other investigators to help inform the various elements of clinical study design, in particular the recruitment and consenting processes and expectations of potential participants regarding the return of individual research findings. PMID:24955380

Kadimpati, Sandeep; McCormick, Jennifer B; Chiu, Yichen; Parker, Ashley B.; Iftikhar, Aliya Z.; Flick, Randall P.; Warner, David O.

2014-01-01

260

Monitoring the Effects of Acupoint Antioxidant Intervention by Measuring Electrical Potential Difference along the Meridian  

PubMed Central

Previous studies suggest that superoxide anions are possibly traveling along acupuncture meridians. The electrical potential difference (EPD) between acupoints may be related to the movement. To test the above hypothesis, we conducted a study investigating the effects of acupoint antioxidant interventions on the meridian EPD. Firstly, ST39 (L) and ST44 (L) were screened out for the EPD detection along the stomach meridian, and ST36 (L) was selected for interventions including acumassage with the control cream, as well as the TAT-SOD cream for 30 minutes, or injection with reduced glutathione sodium. The EPD between ST39 and ST44 was recorded for 80 minutes and measured again 48?h later. While the EPD increased during the acumassage, the acumassage with TAT-SOD cream and the glutathione injection generated waves of EPD increased, indicating the migration or removal from the visceral organ of a greater quantity of superoxide. Remarkably lower EPD readings 48?h later with both antioxidant acupoint interventions than the mere acumassage imply a more complete superoxide flushing out due to the restored superoxide pathway at the acupoint after interventions. The results confirm superoxide transportation along the meridians and demonstrate a possibility of acupoint EPD measurement as a tool to monitor changes in the meridians and acupoints.

Xu, Ming-Ming; Guo, Jing-Ke; Xu, Jin-Sen; Zhang, Chao-Xin; Liu, Shu-Tao; Liao, Ri-Tao; Lin, Chun-Tong; Guo, Jian-Hui; Rao, Ping-Fan

2015-01-01

261

Inhibition and biotransformation potential of veterinary ionophore antibiotics under different redox conditions.  

PubMed

Veterinary ionophore antibiotics (IPAs) are polyether compounds used extensively in the livestock industry to promote animal growth and prevent coccidia infection. However, the environmental fate and impact of IPAs are not fully understood. In this study, the inhibition and biotransformation potential of the most commonly used IPAs, monensin (MON) and salinomycin (SAL), were investigated under well-defined aerobic, nitrate-reducing, fermentative/sulfate-reducing, and fermentative/methanogenic conditions. Batch assays were conducted with mixed cultures developed from poultry litter (PL), PL-fertilized soil, and municipal anaerobic sludge. Significant transformation of MON and SAL was observed in aerobic, low-buffer capacity culture series as a result of abiotic acid-catalyzed IPAs hydrolysis induced by nitrification. Biotransformation of IPAs was the main transformation process in aerobic, high-buffer capacity culture series. MON persisted under fermentative/sulfate-reducing conditions, whereas SAL was transformed by fermentative bacteria. Both MON and SAL were stable under nitrate-reducing and methanogenic conditions. At IPAs concentrations up to 1 mg/L, MON inhibited only methanogenesis, whereas SAL did not impact any of the biological processes investigated in this study. Multiple, new primary IPA biotransformation products were observed on LC/MS, and their molecular structures were tentatively identified by analyzing LC/MS/MS fragmentation patterns. Overall, MON and SAL exhibited different inhibition and biotransformation patterns at each redox condition tested, which could greatly influence their fate and impact upon their release into the environment as a result of agricultural activities. PMID:25340528

Sun, Peizhe; Huang, Ching-Hua; Pavlostathis, Spyros G

2014-11-18

262

Phytochemical screening, antioxidants and antimicrobial potential of Lantana camara in different solvents  

PubMed Central

Objective To evaluate the antioxidant activity, hydrogen peroxide radicals scavenging activity, reducing power, the total phenolic and flavonoids contents, and antimicrobial and antifungal activities of methanol, ethanol and water extracts of leaves of Lantana camara (L. camara). Methods Methanol, ethanol and water extracts were evaluated against four Gram positive and Gram negative bacterial isolates (Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Bacillus subtilis) and two fungal strains (Aspergillus fumigatus and Aspergillus flavus). Methanol extract at different concentrations was tested for antioxidant potential and phytochemicals were determined by using spectrophotometric method. Results The total phenolic content was (40.859±0.017) mg gallic acid/g in the leaves of L. camara, while the total flavonoids was (53.112±0.199) mg/g dry weight. Methanol leaf extract of L. camara showed maximum antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa and was also effective against other bacterial strains as compared to ethanol and aqueous extracts of leaves. The methanol leaf extract of L. camara exhibited significant inhibition (71%) and (66%) against Aspergillus fumigatus and Aspergillus flavus respectively. Conclusions The methanol extract of the L. camara leaves is effective against selected bacterial and fungal strains. Its phytochemical contents have broad antimicrobial properties and the plant might be a novel source of antimicrobial drug.

Naz, Rabia; Bano, Asghari

2013-01-01

263

Dyskinetic potential of dopamine agonists is associated with different striatonigral/striatopallidal zif-268 expression.  

PubMed

In the dopamine-depleted striatum, an altered post-synaptic signalling of efferent neurons might underline the onset of variable dyskinetic responses to dopaminergic agonists. We have previously shown that a subchronic treatment with the D1 agonist SKF-38393 and the D2 agonist ropinirole induces a dyskinetic response of high and low intensities respectively, in 6-hydroxydopamine-lesioned rats. Here, zif-268 mRNA expression was evaluated in striatonigral and striatopallidal neurons to assess a neurochemical marker of these different dyskinetic responses upon drug administration. Acute and subchronic SKF-38393 (3mg/kg) increased zif-268 expression per neuron in the striatonigral pathway, albeit the number of neurons displaying high early-gene levels was reduced by the subchronic treatment. Zif-268 mRNA in striatopallidal neurons was not affected by SKF-38393 treatments. In contrast, ropinirole (5mg/kg) did not alter zif-268 mRNA in striatonigral neurons acutely, whereas ropinirole decreased zif-268 mRNA subchronically. Both acute and subchronic ropinirole decreased zif-268 levels in the striatopallidal pathway. The differential expression of zif-268 in striatonigral and striatopallidal neurons might provide a biochemical correlate of the dyskinetic outcome displayed by SKF-38393 and ropinirole treatments, suggesting that evaluation of neuronal responses upon drug administration provides a tool for the preclinical characterization of dyskinetic potential beyond behavioural tests. PMID:20452347

Carta, Anna R; Frau, Lucia; Pinna, Annalisa; Morelli, Micaela

2010-08-01

264

On the relationship between the tree and its environment, based on electrical potential difference monitoring on trunk of trees  

Microsoft Academic Search

Electrical potential differences (EPD) in the trunk of a Turkey oak tree (measured by using non-polarising electrodes deepened in the sap wood) have been continuously recorded in the Geophysical Observatory \\

A. Koppan; A. Fenyvesi; L. Szarka; V. Wesztergom

2002-01-01

265

Large impact crater histories of Mars: The effect of different model crater age techniques  

NASA Astrophysics Data System (ADS)

Impact events that produce large craters primarily occurred early in the Solar System's history because the largest bolides were remnants from planetary formation. Determining when large impacts occurred on a planetary surface such as Mars can yield clues to the flux of material in the early inner Solar System which, in turn, can constrain other planetary processes such as the timing and magnitude of resurfacing and the history of the martian core dynamo. We have used a large, global planetary database in conjunction with geomorphologic mapping to identify craters superposed on the rims of 78 larger craters with diameters D ? 150 km on Mars, ?78% of which have not been previously dated in this manner. The densities of superposed craters with diameters larger than 10, 16, 25, and 50 km, as well as isochron fits were used to derive model crater ages of these larger craters and basins from which we derived an impact flux. In discussing these ages, we point out several internal inconsistencies of crater-age modeling techniques and chronology systems and, all told, we explain why we think isochron-fitting is the most reliable indicator of an age. Our results point to a mostly obliterated crater record prior to ˜4.0 Ga with the oldest preserved mappable craters on Mars dating to ˜4.3-4.35 Ga. We have used our results to constrain the cessation time of the martian core dynamo which we found to have occurred between the formation of Ladon and Prometheus basins, approximately 4.06-4.09 Ga. We also show that, overall, surfaces on Mars older than ˜4.0-4.1 Ga have experienced >1 km of resurfacing, while those younger than ˜3.8-3.9 Ga have experienced significantly less.

Robbins, Stuart J.; Hynek, Brian M.; Lillis, Robert J.; Bottke, William F.

2013-07-01

266

Semiconducting large bandgap oxides as potential thermoelectric materials for high-temperature power generation?  

NASA Astrophysics Data System (ADS)

Semiconducting large bandgap oxides are considered as interesting candidates for high-temperature thermoelectric power generation (700-1,200 °C) due to their stability, lack of toxicity and low cost, but so far they have not reached sufficient performance for extended application. In this review, we summarize recent progress on thermoelectric oxides, analyze concepts for tuning semiconductor thermoelectric properties with view of their applicability to oxides and determine key drivers and limitations for electrical and thermal transport properties in oxides based on our own experimental work and literature results. For our experimental assessment, we have selected representative multicomponent oxides that range from materials with highly symmetric crystal structure (SrTiO3 perovskite) over oxides with large densities of planar crystallographic defects (Ti n O2 n-1 Magnéli phases with a single type of shear plane, NbO x block structures with intersecting shear planes and WO3- x with more defective block and channel structures) to layered superstructures (Ca3Co4O9 and double perovskites) and also include a wide range of their composites with a variety of second phases. Crystallographic or microstructural features of these oxides are in 0.3-2 nm size range, so that oxide phonons can efficiently interact with them. We explore in our experiments the effects of doping, grain size, crystallographic defects, superstructures, second phases, texturing and (to a limited extend) processing on electric conductivity, Seebeck coefficient, thermal conductivity and figure of merit. Jonker and lattice-versus-electrical conductivity plots are used to compare specific materials and material families and extract levers for future improvement of oxide thermoelectrics. We show in our work that oxygen vacancy doping (reduction) is a more powerful driver for improving the power factor for SrTiO3, TiO2 and NbO x than heterovalent doping. Based on our Seebeck-conductivity plots, we derived a set of highest achievable power factors. We met these best values in our own experiments for our titanium oxide- and niobium oxide-based materials. For strontium titanate-based materials, the estimated highest power factor was not reached; further material improvement is possible and can be reached for materials with higher carrier densities. Our results show that periodic crystallographic defects and superstructures are most efficient in reducing the lattice thermal conductivity in oxides, followed by hetero- and homovalent doping. Due to the small phonon mean free path in oxides, grain boundary scattering in nanoceramics or materials with nanodispersions is much less efficient. We investigated the impact of texturing in Ca3Co4O9 ceramics on thermoelectric performance; we did not find any improvement in the overall in-plane performance of a textured ceramic compared to the corresponding random ceramic.

Backhaus-Ricoult, M.; Rustad, J.; Moore, L.; Smith, C.; Brown, J.

2014-08-01

267

Multicomponent interparticle-potential lattice Boltzmann model for fluids with large viscosity ratios.  

PubMed

This work focuses on an improved multicomponent interparticle-potential lattice Boltzmann model. The model results in viscosity-independent equilibrium densities and is capable of simulating kinematic viscosity ratios greater than 1000. External forces are incorporated into the discrete Boltzmann equation, rather than through an equilibrium velocity shift as in the original Shan and Chen (hereafter, SC) model. The model also requires the derivation of a momentum conserving effective velocity, which is substituted into the equilibrium distribution function and applies to both the single- and multiple-relaxation-time formulations. Additionally, higher-order isotropy is used in the calculation of the fluid-fluid interaction forces to reduce the magnitude of spurious currents (i.e., numerical errors) in the vicinity of interfaces. First, we compare the model to the SC model for static bubble simulations. We demonstrate that the model results in viscosity-independent equilibrium bubble densities for a wide range of kinematic viscosities, which is not the case for the SC model. Furthermore, we show that the model is capable of simulating stable bubbles for kinematic viscosity ratios greater than 1000 (when higher-order isotropy is used), whereas the SC model is known to be limited to kinematic viscosity ratios on the order of 10. Next we verify the model for surface tension via Laplace's law and show that the model results in the same surface tension values for a range of kinematic viscosities and kinematic viscosity ratios of 10, 100, and 1000. The model is also verified for layered cocurrent flow though parallel plates. We show that the simulated velocity profiles preserve continuity at the interface for kinematic viscosity ratios ranging from 0.001 to 1000 and that the model accurately predicts nonwetting and wetting phase relative permeability for kinematic viscosity ratios of 0.01 to 100. PMID:23031047

Porter, Mark L; Coon, E T; Kang, Q; Moulton, J D; Carey, J W

2012-09-01

268

Dimensional overlap between arrows as cueing stimuli and responses?. Evidence from contra-ipsilateral differences in EEG potentials.  

PubMed

In the S1-S2 interval, 400 ms after an arrow as S1, an EEG-potential difference occurs between scalp sites contralateral and ipsilateral to arrow direction. Eimer [J. Exp. Psychol. Hum. Percept. Perform. 21 (1995) 837-854] interpreted this difference as a sign of automatic activation of the manual response, due to dimensional overlap of arrows and responses. However, according to Kornblum et al.'s [Psychol. Rev. 97 (1990) 253-270] notion of dimensional overlap, responses can only be automatically primed if they are included in the response set. Therefore, participants of the present study had to respond to S2 in separate blocks either by key-press, as in Eimer [J. Exp. Psychol. Hum. Percept. Perform. 21 (1995) 837-854], or by making saccades. In addition, contra-ipsilateral differences were recorded not only from central positions, overlying the hand-motor area, but across the whole scalp. Contralateral negativity at 400 ms after S1 was indeed found over the hand-motor area in the 'hand blocks'. However, this 'L-400' (=lateralization at 400 ms) was generally as large in the 'eye' blocks as in the 'hand' blocks. Therefore, L-400 does not reflect automatic activation of manual responses in the sense of Kornblum et al. [Psychol. Rev. 97 (1990) 253-270]. Further, its topographical maximum was more anterior than the hand-motor-related negativity that preceded the manual response ('LRP') with its maximum at central sites. Therefore, L-400 probably does not originate in the hand-motor cortex. Rather, it may be related to activity of the lateral premotor cortex found in fMRI studies of spatial orienting. The present EEG study extends these studies by delimiting the time period of this activity, suggesting that it reflects encoding of the spatial properties of the arrow for action. PMID:10978697

Verleger, R; Vollmer, C; Wauschkuhn, B; van der Lubbe, R H; Wascher, E

2000-09-01

269

Differences in human cortical gene expression match the temporal1 properties of large-scale functional networks2  

E-print Network

1 Differences in human cortical gene expression match the temporal1 properties of large-scale functional networks2 3 4 5 6 Human cortical gene expression and properties of functional networks7 8 9--that the patterns of expression of the 938 genes most40 differentially expressed across the cortex organized

O'Toole, Alice J.

270

A Large Gene Cluster Encoding Several Magnetosome Proteins Is Conserved in Different Species of Magnetotactic Bacteria  

Microsoft Academic Search

In magnetotactic bacteria, a number of specific proteins are associated with the magnetosome membrane (MM) and may have a crucial role in magnetite biomineralization. We have cloned and sequenced the genes of several of these polypeptides in the magnetotactic bacterium Magnetospirillum gryphiswaldense that could be assigned to two different genomic regions. Except for mamA, none of these genes have been

KAREN GRUNBERG; CATHRIN WAWER; BRADLEY M. TEBO; DIRK SCHULER

2001-01-01

271

Large-scale integration of wind power into different energy systems  

Microsoft Academic Search

The paper presents the ability of different energy systems and regulation strategies to integrate wind power. The ability is expressed by the following three factors: the degree of electricity excess production caused by fluctuations in wind and Combined Heat and Power (CHP) heat demands, the ability to utilise wind power to reduce CO2 emission in the system, and the ability

Henrik Lund

2005-01-01

272

Who Gets Market Supplements? Gender Differences within a Large Canadian University  

ERIC Educational Resources Information Center

This study examines the gender pay gap among university faculty by analyzing gender differences in one component of faculty members' salaries--"market premiums." The data were collected during the Fall of 2002 using a survey of faculty at a single Canadian research university. Correspondence analysis and logistic regression analysis were performed…

Doucet, Christine; Durand, Claire; Smith, Michael

2008-01-01

273

Potential of a Future Large Aperture UVOIR Space Observatory for Breakthrough Observations of Star and Planet Formation  

NASA Astrophysics Data System (ADS)

A future large aperture space observatory operating from the UV to the near-infrared with a diameter between 10 and 15 meters will provide a unique opportunity for observations of star and planet formation, from nearby moving groups and associations to star formation in galaxies in the local universe. Our newly formed working group will examine the unique opportunities that such a telescope will give observers in a post-JWST/WFIRST-AFTA era that includes extremely large ground-based observatories such as the TMT, E-ELT, ALMA, and the VLTI. Given a potential suite of instruments for this observatory we will discuss some of the key areas of star and planet formation science where breakthroughs might occur.

Danchi, William C.; Grady, Carol A.; Padgett, Deborah

2015-01-01

274

Sex differences in intellectual performance: analysis of a large cohort of competitive chess players.  

PubMed

Only 1% of the world's chess grandmasters are women. This underrepresentation is unlikely to be caused by discrimination, because chess ratings objectively reflect competitive results. Using data on the ratings of more than 250,000 tournament players over 13 years, we investigated several potential explanations for the male domination of elite chess. We found that (a) the ratings of men are higher on average than those of women, but no more variable; (b) matched boys and girls improve and drop out at equal rates, but boys begin chess competition in greater numbers and at higher performance levels than girls; and (c) in locales where at least 50% of the new young players are girls, their initial ratings are not lower than those of boys. We conclude that the greater number of men at the highest levels in chess can be explained by the greater number of boys who enter chess at the lowest levels. PMID:17201785

Chabris, Christopher F; Glickman, Mark E

2006-12-01

275

Potential vertical movement of large heat-generating waste packages in salt.  

SciTech Connect

With renewed interest in disposal of heat-generating waste in bedded or domal salt formations, scoping analyses were conducted to estimate rates of waste package vertical movement. Vertical movement is found to result from thermal expansion, from upward creep or heave of the near-field salt, and from downward buoyant forces on the waste package. A two-pronged analysis approach was used, with thermal-mechanical creep modeling, and coupled thermal-viscous flow modeling. The thermal-mechanical approach used well-studied salt constitutive models, while the thermal-viscous approach represented the salt as a highly viscous fluid. The Sierra suite of coupled simulation codes was used for both approaches. The waste package in all simulations was a right-circular cylinder with the density of steel, in horizontal orientation. A time-decaying heat generation function was used to represent commercial spent fuel with typical burnup and 50-year age. Results from the thermal-mechanical base case showed approximately 27 cm initial uplift of the package, followed by gradual relaxation closely following the calculated temperature history. A similar displacement history was obtained with the package density set equal to that of salt. The slight difference in these runs is attributable to buoyant displacement (sinking) and is on the order of 1 mm in 2,000 years. Without heat generation the displacement stabilizes at a fraction of millimeter after a few hundred years. Results from thermal-viscous model were similar, except that the rate of sinking was constant after cooldown, at approximately 0.15 mm per 1,000 yr. In summary, all calculations showed vertical movement on the order of 1 mm or less in 2,000 yr, including calculations using well-established constitutive models for temperature-dependent salt deformation. Based on this finding, displacement of waste packages in a salt repository is not a significant repository performance issue.

Clayton, Daniel James; Martinez, Mario J.; Hardin, Ernest L.

2013-05-01

276

Complex genetic architecture of population differences in adult lifespan of a beetle: nonadditive inheritance, gender differences, body size and a large maternal effect.  

PubMed

Evolutionary responses to selection can be complicated when there is substantial nonadditivity, which limits our ability to extrapolate from simple models of selection to population differentiation and speciation. Studies of Drosophila melanogaster indicate that lifespan and the rate of senescence are influenced by many genes that have environment- and sex-specific effects. These studies also demonstrate that interactions among alleles (dominance) and loci (epistasis) are common, with the degree of interaction differing between the sexes and among environments. However, little is known about the genetic architecture of lifespan or mortality rates for organisms other than D. melanogaster. We studied genetic architecture of differences in lifespan and shapes of mortality curves between two populations of the seed beetle, Callosobruchus maculatus (South India and Burkina Faso populations). These two populations differ in various traits (such as body size and adult lifespan) that have likely evolved via host-specific selection. We found that the genetic architecture of lifespan differences between populations differs substantially between males and females; there was a large maternal effect on male lifespan (but not on female lifespan), and substantial dominance of long-life alleles in females (but not males). The large maternal effect in males was genetically based (there was no significant cytoplasmic effect) likely due to population differences in maternal effects genes that influence lifespan of progeny. Rearing host did not affect the genetic architecture of lifespan, and there was no evidence that genes on the Y-chromosome influence the population differences in lifespan. Epistatic interactions among loci were detectable for the mortality rate of both males and females, but were detectable for lifespan only after controlling for body size variation among lines. The detection of epistasis, dominance, and sex-specific genetic effects on C. maculatus lifespan is consistent with results from line cross and quantitative trait locus studies of D. melanogaster. PMID:15312073

Fox, C W; Czesak, M E; Wallin, W G

2004-09-01

277

Acute mannitol and saline volume expansion in the rat: effect on transepithelial potential difference in proximal tubules.  

PubMed

1. Transepithelial potential difference (PDte) of proximal tubules was measured in rats under control conditions (C), and mannitol-saline and saline extracellular fluid volume expansion (MVE, SVE, respectively) under conditions of normal net lumen to basal sodium transport. 2. PDte was measured in kidneys bathed with Hartmann's solution or covered with mineral oil under both volume-expanded conditions together with their controls. 3. PDte was significantly lower in kidneys bathed with Hartmann's solution than those covered with oil. 4. In MVE rats, with mineral oil covering the kidneys, PDte (expressed as mean and s.e.m.) was for the control 2.20 +/- 0.05 (n = 45) mV and MVE 1.97 +/- 0.04 (n = 36) mV, lumen positive, a significant reduction of 10% (P less than 0.001). In SVE rats, with mineral oil covering the kidneys, PDte was for C = 2.42 +/- 0.05 (n = 74) mV and SVE = 1.93 +/- 0.03 (n = 67) mV, a significant reduction (P less than 0.001) of 20%. 5. According to thermodynamic considerations, neither of these changes is sufficient to explain the 50% inhibition of Na transport measured previously during MVE and SVE with autologous tubular fluid. The present results offer further evidence supporting the idea that the inhibition of Na transport during MVE and SVE is largely due to inhibition of the active Na transporting step. PMID:2112434

Sugo, E; Györy, A Z

1990-01-01

278

Supplier involvement in automotive component design: are there really large US Japan differences?  

Microsoft Academic Search

Typical descriptions of Japanese supplier management portray first-tier suppliers as partners in product development from the early concept stages of design, whereas US first-tier suppliers are provided detailed specifications and blueprints and build to print. This paper examines US\\/Japan differences in supplier involvement in design based on a 1993 survey of 143 Japanese and 189 US automotive component suppliers. The

Jeffrey K. Liker; Rajan R. Kamath; S. Nazli Wasti; Mitsuo Nagamachi

1996-01-01

279

On the origin of the electrostatic potential difference at a liquid-vacuum interface  

PubMed Central

The microscopic origin of the interface potential calculated from computer simulations is elucidated by considering a simple model of molecules near an interface. The model posits that molecules are isotropically oriented and their charge density is Gaussian distributed. Molecules that have a charge density that is more negative toward their interior tend to give rise to a negative interface potential relative to the gaseous phase, while charge densities more positive toward their interior give rise to a positive interface potential. The interface potential for the model is compared to the interface potential computed from molecular dynamics simulations of the nonpolar vacuum-methane system and the polar vacuum-water interface system. The computed vacuum-methane interface potential from a molecular dynamics simulation (?220?mV) is captured with quantitative precision by the model. For the vacuum-water interface system, the model predicts a potential of ?400?mV compared to ?510?mV, calculated from a molecular dynamics simulation. The physical implications of this isotropic contribution to the interface potential is examined using the example of ion solvation in liquid methane. PMID:19102551

Harder, Edward; Roux, Benoît

2008-01-01

280

Acute hypertension selectively potentiates constrictor responses of large coronary arteries to serotonin by altering endothelial function in vivo.  

PubMed

We tested the hypothesis that acute coronary artery hypertension may damage vascular endothelium and alter vasomotor responses to humoral agents. We examined effects of intracoronary infusion of the endothelium-dependent agent serotonin and two endothelium-independent agents, angiotensin II and methoxamine, on large coronary artery diameter in the blood perfused dog heart. Responses were examined before and 30 minutes after brief periods of coronary hypertension (200 mm Hg for 10 seconds to 15 minutes). In open-chest anesthetized dogs, the left anterior descending coronary artery was perfused at constant pressure. Coronary diameter (D) was measured with piezoelectric crystals. At a control perfusion pressure of 80 mm Hg, serotonin produced dose-dependent constriction of the large coronary artery (mean +/- SEM; delta D = -22 +/- 10 microns at 5 micrograms/min; -108 +/- 50 microns at 50 micrograms/min). Increasing perfusion pressure to 200 mm Hg increased flow 515 +/- 79% and coronary diameter 509 +/- 9 microns. After 15 minutes of hypertension, when coronary diameter had returned to baseline values, the constriction of the large artery to serotonin was potentiated (delta D = -89 +/- 33 microns at 5 micrograms/min; -207 +/- 45 microns at 50 micrograms/min; p less than 0.05). Hypertension for 1-5 minutes potentiated constrictor responses of large coronary arteries for at least 2 1/2 hours. Removal of endothelium prevented effects of hypertension on constrictor responses of large arteries to serotonin. Hypertension did not alter constrictor responses to angiotension II (1 and 2.5 micrograms/min) or methoxamine (50 and 100 micrograms/min) or the dilator response to acetylcholine (40 micrograms/min). Acute hypertension altered endothelial morphology. There were small endothelial craters following 10 seconds of hypertension, and disruption of endothelial junctions with leukocyte adherence following 1-15 minutes of hypertension. We conclude that acute hypertension alters constrictor responses of large coronary arteries to serotonin by impairing endothelial function and not by directly affecting vascular smooth muscle. These effects of acute hypertension on vascular reactivity are selective in that they do not involve non-endothelium-dependent agents or the endothelium-dependent agent, acetylcholine. The effect of hypertension also persists long after pressure is restored to normotensive levels. PMID:3677343

Lamping, K G; Dole, W P

1987-12-01

281

Are large time differences in meteorite formation real. [cosmochronological dating and nucleosynthetic ratios  

NASA Technical Reports Server (NTRS)

Considerations are given concerning the interpretation of the results of two types of cosmochronological dating in order to examine the validity of the conclusions inferred from these results that the time intervals between the formation of various meteorite samples are very great. It is theorized that the isotopic differences between Angra dos Reis and other basaltic achondrites may be due to real fluctuations between the relative abundances of s-process and r-process nucleosynthesis products at a level delta about 0.001.

Cameron, A. G. W.

1973-01-01

282

Addressing impacts of different statistical downscaling methods on large scale hydrologic simulations  

NASA Astrophysics Data System (ADS)

Many hydrologic assessments, such as evaluations of climate change impacts on water resources, require downscaled climate model outputs to force hydrologic simulations at a spatial resolution finer than the climate models' native scale. Statistical downscaling is an attractive alternative to dynamical downscaling methods for continental scale hydrologic applications because of its lower computational cost. The goal of this study is to illustrate and compare how the errors in precipitation and temperature produced by different statistical downscaling methods propagate into hydrologic simulations. Multi-decadal hydrologic simulations were performed with three process-based hydrologic models (CLM, VIC, and PRMS) forced by multiple climate datasets over the contiguous United States. The forcing datasets include climate data derived from gauge observations (M02) as well as climate data downscaled from the NCEP-NCAR reanalysis using 4 statistical downscaling methods for a domain with 12-km grid spacing: two forms of Bias Corrected Spatially Disaggregated methods (BCSD-monthly and BCSD-daily), Bias Corrected Constructed Analogue (BCCA), and Asynchronous Regression (AR). Our results show that both BCCA and BCSD-daily underestimate extreme precipitation events while AR produces these correctly at the scale at which the simulations were run but does not scale them up appropriately to larger basin scales like HUC-4 and HUC-2. These artifacts lead to a poor representation of flooding events when hydrologic models are forced by these methods over a range of spatial scales. We also illustrate that errors in precipitation depths dominate impacts on runoff depth estimations, and that errors in wet day frequency have a larger effect on shortwave radiation estimations than do the errors in temperatures; this error subsequently affects the partitioning of precipitation into evaporation and runoff as we show over mountainous areas of the upper Colorado River. Finally we show the inter-model differences across our simulations are generally lower than than inter-forcing data differences. We conclude with preliminary guidance on sound methodological choices for future climate impact studies using these methods. Comparison of annual precipitation between statistically downscaled data and observation (M02) and illustration of how these differences propagate into hydrologic simulations with two models. Figure shows the simulations over the western United States.

Mizukami, N.; Clark, M. P.; Gutmann, E. D.; Mendoza, P. A.; Brekke, L. D.; Arnold, J.; Raff, D. A.

2013-12-01

283

Facilitation of motor evoked potentials (MEPs) in first dorsal interosseous (FDI) muscle is dependent on different motor images  

Microsoft Academic Search

Objective: We investigated changes in motor evoked potentials (MEPs) to explain why mental practice can improve motor performance.Methods: MEPs were recorded from right and left first dorsal interosseous (FDI) muscles of 9 normal, right-handed subjects during different motor images of index finger movement: (1) rest, (2) flexion, (3) abduction, (4) extension. A paired t test was used to compare differences

Susumu Yahagi; Tatsuya Kasai

1998-01-01

284

Target Repression Induced by Endogenous microRNAs: Large Differences, Small Effects  

PubMed Central

MicroRNAs are small RNAs that regulate protein levels. It is commonly assumed that the expression level of a microRNA is directly correlated with its repressive activity – that is, highly expressed microRNAs will repress their target mRNAs more. Here we investigate the quantitative relationship between endogenous microRNA expression and repression for 32 mature microRNAs in Drosophila melanogaster S2 cells. In general, we find that more abundant microRNAs repress their targets to a greater degree. However, the relationship between expression and repression is nonlinear, such that a 10-fold greater microRNA concentration produces only a 10% increase in target repression. The expression/repression relationship is the same for both dominant guide microRNAs and minor mature products (so-called passenger strands/microRNA* sequences). However, we find examples of microRNAs whose cellular concentrations differ by several orders of magnitude, yet induce similar repression of target mRNAs. Likewise, microRNAs with similar expression can have very different repressive abilities. We show that the association of microRNAs with Argonaute proteins does not explain this variation in repression. The observed relationship is consistent with the limiting step in target repression being the association of the microRNA/RISC complex with the target site. These findings argue that modest changes in cellular microRNA concentration will have minor effects on repression of targets. PMID:25141277

Ninova, Maria; Griffiths-Jones, Sam; Ronshaugen, Matthew

2014-01-01

285

Sensitivity tests on the criterion of potential vorticity index for discriminating the location of ozone sources and sinks over large continental areas  

NASA Astrophysics Data System (ADS)

This paper presents the results of a sensitivity analysis of a statistical-dynamic model (ISOGASP, standing for Identification of SOurces of greenhouse GAS Plus), developed by our research group to reconstruct 3D concentration patterns of greenhouse gases in large and deep atmospheric regions over continental or oceanic areas and extending vertically from the lower troposphere to the lower stratosphere. The results of this analysis have shown the ability of the ISOGASP model to discriminate the locations of ozone sources, according to the geographical distribution patterns of atmospheric O3 concentration inside a limited number of atmospheric layers at different heights above sea level, reconstructed through the method of backward trajectories simulating the travel of air parcels from each different layer to the receptor points at their own height. The potential vorticity index has been used to discriminate the sub-sets of trajectories belonging to stratosphere or troposphere.

Cacòpardo, T.; Ferrarese, S.; Longhetto, A.; Cassardo, C.

2004-03-01

286

The theoretical foundations and potential for large-eddy simulation (LES) in fluvial geomorphic and sedimentological research  

NASA Astrophysics Data System (ADS)

Large-eddy simulation (LES) is a method for resolving the time-dependent structure of high Reynolds number, turbulent flows. With LES it is possible to model and track the behaviour of coherent turbulent structures and study their effect on the flow field. Hence, LES is potentially an important research tool in the fluvial sciences where flow mixing, sediment entrainment and sediment transport are all affected by the presence of coherent vortices and their interactions with channel boundaries and other flow structures. This paper introduces the LES methodology, discusses a variety of ways for representing small-scale processes within LES (the subgrid-scale modelling problem), and provides some examples of early work into the use of LES in a fluvial context. A number of advances in computational power and numerical methods are required before LES can be effectively applied at the river reach scale. This paper considers some recent developments and their potential for providing validated large-eddy simulations of river flow at the channel scale.

Keylock, C. J.; Hardy, R. J.; Parsons, D. R.; Ferguson, R. I.; Lane, S. N.; Richards, K. S.

2005-08-01

287

Uncertainty of SWAT model at different DEM resolutions in a large mountainous watershed.  

PubMed

The objective of this study was to enhance understanding of the sensitivity of the SWAT model to the resolutions of Digital Elevation Models (DEMs) based on the analysis of multiple evaluation indicators. The Xiangxi River, a large tributary of Three Gorges Reservoir in China, was selected as the study area. A range of 17 DEM spatial resolutions, from 30 to 1000 m, was examined, and the annual and monthly model outputs based on each resolution were compared. The following results were obtained: (i) sediment yield was greatly affected by DEM resolution; (ii) the prediction of dissolved oxygen load was significantly affected by DEM resolutions coarser than 500 m; (iii) Total Nitrogen (TN) load was not greatly affected by the DEM resolution; (iv) Nitrate Nitrogen (NO?-N) and Total Phosphorus (TP) loads were slightly affected by the DEM resolution; and (v) flow and Ammonia Nitrogen (NH?-N) load were essentially unaffected by the DEM resolution. The flow and dissolved oxygen load decreased more significantly in the dry season than in the wet and normal seasons. Excluding flow and dissolved oxygen, the uncertainties of the other Hydrology/Non-point Source (H/NPS) pollution indicators were greater in the wet season than in the dry and normal seasons. Considering the temporal distribution uncertainties, the optimal DEM resolutions for flow was 30-200 m, for sediment and TP was 30-100 m, for dissolved oxygen and NO?-N was 30-300 m, for NH?-N was 30 to 70 m and for TN was 30-150 m. PMID:24509347

Zhang, Peipei; Liu, Ruimin; Bao, Yimeng; Wang, Jiawei; Yu, Wenwen; Shen, Zhenyao

2014-04-15

288

Differences in Human Cortical Gene Expression Match the Temporal Properties of Large-Scale Functional Networks  

PubMed Central

We explore the relationships between the cortex functional organization and genetic expression (as provided by the Allen Human Brain Atlas). Previous work suggests that functional cortical networks (resting state and task based) are organized as two large networks (differentiated by their preferred information processing mode) shaped like two rings. The first ring–Visual-Sensorimotor-Auditory (VSA)–comprises visual, auditory, somatosensory, and motor cortices that process real time world interactions. The second ring–Parieto-Temporo-Frontal (PTF)–comprises parietal, temporal, and frontal regions with networks dedicated to cognitive functions, emotions, biological needs, and internally driven rhythms. We found–with correspondence analysis–that the patterns of expression of the 938 genes most differentially expressed across the cortex organized the cortex into two sets of regions that match the two rings. We confirmed this result using discriminant correspondence analysis by showing that the genetic profiles of cortical regions can reliably predict to what ring these regions belong. We found that several of the proteins–coded by genes that most differentiate the rings–were involved in neuronal information processing such as ionic channels and neurotransmitter release. The systematic study of families of genes revealed specific proteins within families preferentially expressed in each ring. The results showed strong congruence between the preferential expression of subsets of genes, temporal properties of the proteins they code, and the preferred processing modes of the rings. Ionic channels and release-related proteins more expressed in the VSA ring favor temporal precision of fast evoked neural transmission (Sodium channels SCNA1, SCNB1 potassium channel KCNA1, calcium channel CACNA2D2, Synaptotagmin SYT2, Complexin CPLX1, Synaptobrevin VAMP1). Conversely, genes expressed in the PTF ring favor slower, sustained, or rhythmic activation (Sodium channels SCNA3, SCNB3, SCN9A potassium channels KCNF1, KCNG1) and facilitate spontaneous transmitter release (calcium channel CACNA1H, Synaptotagmins SYT5, Complexin CPLX3, and synaptobrevin VAMP2). PMID:25546015

Cioli, Claudia; Abdi, Hervé; Beaton, Derek; Burnod, Yves; Mesmoudi, Salma

2014-01-01

289

Differences in human cortical gene expression match the temporal properties of large-scale functional networks.  

PubMed

We explore the relationships between the cortex functional organization and genetic expression (as provided by the Allen Human Brain Atlas). Previous work suggests that functional cortical networks (resting state and task based) are organized as two large networks (differentiated by their preferred information processing mode) shaped like two rings. The first ring--Visual-Sensorimotor-Auditory (VSA)--comprises visual, auditory, somatosensory, and motor cortices that process real time world interactions. The second ring--Parieto-Temporo-Frontal (PTF)--comprises parietal, temporal, and frontal regions with networks dedicated to cognitive functions, emotions, biological needs, and internally driven rhythms. We found--with correspondence analysis--that the patterns of expression of the 938 genes most differentially expressed across the cortex organized the cortex into two sets of regions that match the two rings. We confirmed this result using discriminant correspondence analysis by showing that the genetic profiles of cortical regions can reliably predict to what ring these regions belong. We found that several of the proteins--coded by genes that most differentiate the rings--were involved in neuronal information processing such as ionic channels and neurotransmitter release. The systematic study of families of genes revealed specific proteins within families preferentially expressed in each ring. The results showed strong congruence between the preferential expression of subsets of genes, temporal properties of the proteins they code, and the preferred processing modes of the rings. Ionic channels and release-related proteins more expressed in the VSA ring favor temporal precision of fast evoked neural transmission (Sodium channels SCNA1, SCNB1 potassium channel KCNA1, calcium channel CACNA2D2, Synaptotagmin SYT2, Complexin CPLX1, Synaptobrevin VAMP1). Conversely, genes expressed in the PTF ring favor slower, sustained, or rhythmic activation (Sodium channels SCNA3, SCNB3, SCN9A potassium channels KCNF1, KCNG1) and facilitate spontaneous transmitter release (calcium channel CACNA1H, Synaptotagmins SYT5, Complexin CPLX3, and synaptobrevin VAMP2). PMID:25546015

Cioli, Claudia; Abdi, Hervé; Beaton, Derek; Burnod, Yves; Mesmoudi, Salma

2014-01-01

290

Large work function difference driven electron transfer from electrides to single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

A difference in work function plays a key role in charge transfer between two materials. Inorganic electrides provide a unique opportunity for electron transfer since interstitial anionic electrons result in a very low work function of 2.4-2.6 eV. Here we investigated charge transfer between two different types of electrides, [Ca2N]+.e- and [Ca24Al28O64]4+.4e-, and single-walled carbon nanotubes (SWNTs) with a work function of 4.73-5.05 eV. [Ca2N]+.e- with open 2-dimensional electron layers was more effective in donating electrons to SWNTs than closed cage structured [Ca24Al28O64]4+.4e- due to the higher electron concentration (1.3 × 1022 cm-3) and mobility (~200 cm2 V-1 s-1 at RT). A non-covalent conjugation enhanced near-infrared fluorescence of SWNTs as high as 52%. The field emission current density of electride-SWNT-silver paste dramatically increased by a factor of 46 000 (14.8 mA cm-2) at 2 V ?m-1 (3.5 wt% [Ca2N]+.e-) with a turn-on voltage of 0.85 V ?m-1.A difference in work function plays a key role in charge transfer between two materials. Inorganic electrides provide a unique opportunity for electron transfer since interstitial anionic electrons result in a very low work function of 2.4-2.6 eV. Here we investigated charge transfer between two different types of electrides, [Ca2N]+.e- and [Ca24Al28O64]4+.4e-, and single-walled carbon nanotubes (SWNTs) with a work function of 4.73-5.05 eV. [Ca2N]+.e- with open 2-dimensional electron layers was more effective in donating electrons to SWNTs than closed cage structured [Ca24Al28O64]4+.4e- due to the higher electron concentration (1.3 × 1022 cm-3) and mobility (~200 cm2 V-1 s-1 at RT). A non-covalent conjugation enhanced near-infrared fluorescence of SWNTs as high as 52%. The field emission current density of electride-SWNT-silver paste dramatically increased by a factor of 46 000 (14.8 mA cm-2) at 2 V ?m-1 (3.5 wt% [Ca2N]+.e-) with a turn-on voltage of 0.85 V ?m-1. Electronic supplementary information (ESI) available: The acronyms of base materials and synthesized specimens, field emission characteristics of PSWNT-Ag paste and HSWNT-Ag paste, additional XPS and Raman data, estimation of transferred electrons from electrides to nanotubes, optical images of C12A7:e--HSWNT films, a SEM image of the tape-activated PSWNT-Ag paste, and comparison of field emission properties. See DOI: 10.1039/c4nr01629g

Menamparambath, Mini Mol; Park, Jong-Ho; Yoo, Ho-Sung; Patole, Shashikant P.; Yoo, Ji-Beom; Kim, Sung Wng; Baik, Seunghyun

2014-07-01

291

Potential impact of atmospheric N deposition on soil N2O emission varies with different soil N regimes  

NASA Astrophysics Data System (ADS)

Future increases in nitrogen (N) deposition has the potential to change belowground nutrient dynamics, especially N cycle, and thereby can alter the soil-atmosphere exchange of nitrous oxide (N2O) which is one of the major greenhouse gases. Moreover, we considered that their effect on soil N2O emission varies with different soil N levels because N2O is a by-product of the biological nitrification process in aerobic soil environments and of the biological denitrification process in anaerobic soil environments. To understand the changes in soil N2O flux under different soil N, we carried out simulated N addition experiment in three-year-old hybrid larch F1 (F1: Larix gmelinii var. japonica × Larix kaempferi) plantation during two growing seasons 2008 - 2009. The hybrid larch F1 was developed to make up for several problems of larch species, e.g. a high susceptibility to disease or grazing damage by insects and fungi, and a large number of this seedlings are planted recently in northern Japan. Based on soil analysis, we selected two sites which have different soil N concentration, i.e. low-N and high-N concentrations. Nitrogen input was initiated at the onset of our experiment, and included four treatments with four replications: Low-N soil + Zero-N control, Low-N soil + 50 kg-N addition, High-N soil + Zero-N control and High-N soil + 50 kg-N addition. The N was added as ammonium nitrate (NH4NO3) solution distributed in four occasions during each growing season. Gas and soil samples were taken from each plot on ten occasions at a time during each growing season. Collected N2O concentrations were determined by a gas chromatograph (GC-14B; Shimadzu, Kyoto, Japan) equipped with an electron capture detector, while total-N and inorganic-N concentrations were obtained by a NC analyzer (Sumigraph NC-1000; Sumica Chemical Analysis Service Ltd., Osaka, Japan) and an auto analyzer (AACS-4; BL-TEC Inc., Osaka, Japan), respectively. Before the N addition, initial total-N in High-N soil was almost two times higher than that of Low-N soil, but there were no significant differences in physical soil properties among four treatments, e.g. bulk density and water-filled pore space. During the measurement period, N addition increased NH4-N and NO3-N concentrations (P < 0.01), and therefore stimulated soil N2O emissions from 50 kg-N addition plots in both soil N regimes (P < 0.05). Furthermore, increased levels of soil N2O flux in High-N soil were higher than that of Low-N soil (P < 0.001). In this study, we found a positive spatial relationship between soil N2O emission and NO3-N concentration (R2 = 0.80, P < 0.0001). Overall, N addition induced emission in High-N soil was equivalent to 1.66% of the applied N. This value is over the IPCC 1.25% default value, but the loss of 0.69% in Low-N soil is considerably lower than the IPCC mean default value. In conclusion, our results suggest that soil N2O emission seems to largely depend on whether the ecosystem N limited or not at the time of N inputs. Nitrogen cycling in forest ecosystems, which already exhibits large N2O emission, responded strongly to the added N, where as an ecosystem that has been limited by N uses up the added N rapidly and soil N2O emission was elevated only for a short term.

Kim, Y.; Yi, M.; Koike, T.

2011-12-01

292

Cytoskeletal stiffness, friction, and fluidity of cancer cell lines with different metastatic potential  

PubMed Central

We quantified mechanical properties of cancer cells differing in metastatic potential. These cells included normal and H-ras-transformed NIH3T3 fibroblast cells, normal and oncoprotein-overexpressing MCF10A breast cancer cells, and weakly and strongly metastatic cancer cell line pairs originating from human cancers of the skin (A375P and A375SM cells), kidney (SN12C and SN12PM6 cells), prostate (PC3M and PC3MLN4 cells), and bladder (253J and 253JB5 cells). Using magnetic twisting cytometry, cytoskeletal stiffness (g?) and internal friction (g?) were measured over a wide frequency range. The dependencies of g? and g? upon frequency were used to determine the power law exponent x which is a direct measure of cytoskeletal fluidity and quantifies where the cytoskeleton resides along the spectrum of solid-like (x = 1) to fluid-like (x = 2) states. Cytoskeletal fluidity x increased following transformation by H-ras oncogene expression in NIH3T3 cells, overexpression of ErbB2 and 14-3-3-? in MCF10A cells, and implantation and growth of PC3M and 253J cells in the prostate and bladder, respectively. Each of these perturbations that had previously been shown to enhance cancer cell motility and invasion are shown here to shift the cytoskeleton towards a more fluid-like state. In contrast, strongly metastatic A375SM and SN12PM6 cells that disseminate by lodging in the micro-circulation of peripheral organs had smaller x than did their weakly metastatic cell line pairs A375P and SN12C, respectively. Thus, enhanced hematological dissemination was associated with decreased x and a shift towards a more solid-like cytoskeleton. Taken together, these results are consistent with the notion that adaptations known to enhance metastatic ability in cancer cell lines define a spectrum of fluid-like versus solid-like states, and the position of the cancer cell within this spectrum may be a determinant of cancer progression. PMID:22961212

Coughlin, Mark F.; Bielenberg, Diane R.; Lenormand, Guillaume; Marinkovic, Marina; Waghorne, Carol G.; Zetter, Bruce R.; Fredberg, Jeffrey J.

2013-01-01

293

Cytoskeletal stiffness, friction, and fluidity of cancer cell lines with different metastatic potential.  

PubMed

We quantified mechanical properties of cancer cells differing in metastatic potential. These cells included normal and H-ras-transformed NIH3T3 fibroblast cells, normal and oncoprotein-overexpressing MCF10A breast cancer cells, and weakly and strongly metastatic cancer cell line pairs originating from human cancers of the skin (A375P and A375SM cells), kidney (SN12C and SN12PM6 cells), prostate (PC3M and PC3MLN4 cells), and bladder (253J and 253JB5 cells). Using magnetic twisting cytometry, cytoskeletal stiffness (g') and internal friction (g?) were measured over a wide frequency range. The dependencies of g' and g? upon frequency were used to determine the power law exponent x which is a direct measure of cytoskeletal fluidity and quantifies where the cytoskeleton resides along the spectrum of solid-like (x = 1) to fluid-like (x = 2) states. Cytoskeletal fluidity x increased following transformation by H-ras oncogene expression in NIH3T3 cells, overexpression of ErbB2 and 14-3-3-? in MCF10A cells, and implantation and growth of PC3M and 253J cells in the prostate and bladder, respectively. Each of these perturbations that had previously been shown to enhance cancer cell motility and invasion are shown here to shift the cytoskeleton towards a more fluid-like state. In contrast, strongly metastatic A375SM and SN12PM6 cells that disseminate by lodging in the microcirculation of peripheral organs had smaller x than did their weakly metastatic cell line pairs A375P and SN12C, respectively. Thus, enhanced hematological dissemination was associated with decreased x and a shift towards a more solid-like cytoskeleton. Taken together, these results are consistent with the notion that adaptations known to enhance metastatic ability in cancer cell lines define a spectrum of fluid-like versus solid-like states, and the position of the cancer cell within this spectrum may be a determinant of cancer progression. PMID:22961212

Coughlin, Mark F; Bielenberg, Diane R; Lenormand, Guillaume; Marinkovic, Marina; Waghorne, Carol G; Zetter, Bruce R; Fredberg, Jeffrey J

2013-03-01

294

Cosmic expansion driven by real scalar field for different forms of potential  

E-print Network

We discuss the expansion of the universe in the FRLW model assuming that the source of dark energy is either tachyonic scalar field or quintessence. The tachyonic scalar field with exponential and power-law potential (function of homogeneous scalar field $\\phi$) both gives exponential expansion of the universe. It is found that this behaviour is not distinguishable from the quintessence with respect to these potentials.

Murli Manohar Verma; Shankar Dayal Pathak

2013-11-12

295

Annual surveys of larval Ambystoma cingulatum reveal large differences in dates of pond residency  

SciTech Connect

Effective sampling of pond-dwelling larval stages of the federally listed Ambystoma cingulatum (Flatwoods Salamander) requires sufficient knowledge of when larvae are present and how best to sample them. Through systematic sampling with active and passive sampling techniques, we found dipnetting to be significantly more effective than three types of passive traps. During surveys for Flatwoods Salamander larvae at Fort Stewart Military Installation, GA in 2005 and 2006, we found that pond residency varied by at least 1.5 months between the 2 years due to the timing of pond filling. In addition, our latest capture on 23 May 2005 was about 2 weeks later than previously recorded at any site range-wide. A simple growth model was used to evaluate likely hatching dates based on significant rain events, observed sizes at capture, and likely growth rates. This analysis suggested that the primary dates of hatching occurred in late February 2005 and early January 2006, a difference that corresponds to that seen in the residency of the latest larval stages. A review of the survey records for Fort Stewart for the past 13 years shows a steep decline in the number of occupied ponds from near 20 to a single pond for the past two years (the only documented breeding success in a natural pond since 1999).

Bevelhimer, Mark S [ORNL; Giffen, Neil R [ORNL; Stevenson, Dirk [Ft Stewart Fish and Wildlife Branch

2008-05-01

296

Examination of sex differences in a large sample of young children with autism spectrum disorder and typical development.  

PubMed

Despite consistent and substantive research documenting a large male to female ratio in Autism Spectrum Disorder (ASD), only a modest body of research exists examining sex differences in characteristics. This study examined sex differences in developmental functioning and early social communication in children with ASD as compared to children with typical development. Sex differences in adaptive behavior and autism symptoms were also examined in children with ASD. Participants (n = 511) were recruited from the Florida State University FIRST WORDS(®) Project and University of Michigan Autism and Communication Disorders Center. Analyses did not reveal significant effects of sex or a diagnostic group by sex interaction, suggesting a similar phenotype in males and females early in development. Further research is needed to examine sex differences across development. PMID:25189824

Reinhardt, Vanessa P; Wetherby, Amy M; Schatschneider, Christopher; Lord, Catherine

2015-03-01

297

The measurement of large optical frequency differences and the design of a new type of frequency chain  

Microsoft Academic Search

We have used optical frequency interval dividers, optical frequency comb generators and mode-locked lasers to measure large optical frequency differences of up to 45.2 THz between laser frequencies. We have shown that the modes of a mode-locked laser are distributed uniformly in frequency space within the experimental limit of 3.0 parts in 1017 and that the mode separation equals the

Thomas Udem; Jorg Reichert; Ronald Holzwarth; Theodor Hansch; Motonobu Kourogi

1999-01-01

298

Low-frequency fatigue, post-tetanic potentiation and their interaction at different muscle lengths following eccentric exercise  

Microsoft Academic Search

Low-frequency fatigue (LFF) and post-tetanic potentiation (PTP) were quantified at different muscle lengths in rat medial gastrocnemius (GM) muscle. In situ experiments were performed on GM muscle-tendon complexes of anaesthetised (urethane, 1.5·g·kg-1 i.p.) Wistar rats (N=8). Force-length characteristics were determined at maximal (200·Hz) and submaximal (60·Hz) stimulation. Data for submaximally stimulated muscle were obtained in a non-potentiated and in a

J. M. Rijkelijkhuizen; C. J. de Ruiter; P. A. Huijing; A. de Haan

2005-01-01

299

Large-Scale, Complex Shaped Coastline Responses to Different Forms of Local Shoreline Stabilization and Climate Change  

NASA Astrophysics Data System (ADS)

Nowhere is the importance of research addressing the dynamics of coupled human-landscape processes more pronounced than on the world’s coasts, where human shoreline stabilization alters the natural evolution of the coastline on large spatial and temporal scales. Slott et al. (2010) extended a recently developed large-scale coastline evolution model to include the effects of beach ‘nourishment’ (importing sand into the nearshore system at a long term rate sufficient to counteract shoreline erosion) on a complex-shaped coastline, finding a surprising human signal over large (100s km) distances (Figure 1); even localized shoreline stabilization efforts, when maintained over decadal time scales, can significantly affect the regional pattern of coastline morphological adjustment in response to changing storm behaviors (Slott, et al., 2010). In this work, we examine the effects of shoreline-stabilization method that involve hard structures, such as sea walls and groyne fields. These methods differ significantly from beach nourishment in terms of large-scale impacts; they hold the shoreline location fixed without adding a flux of sediment into the system. Like beach nourishment, these human manipulations have widespread, significant effects on shoreline change rates, even when the manipulations only occur locally. However, the effects on large-scale coastline morphodynamics also exhibit interesting differences when compared to the beach nourishment case. References Slott, Jordan, A. B. Murray, Andrew Ashton, 2010. Large-Scale Responses of Complex-Shaped Coastlines to Local Shoreline Stabilization and Climate Change, Journal of Geophysical Research—Earth Surface. Figure 1. Evolution of a cuspate-cape shoreline in response to ongoing beach nourishment over 200 years, for six different site selections. a. Initial model shoreline, developed in response to a wave climate approximating recent conditions off of the Carolina coast, USA. b. The influence that beach nourishment had on coastline change, with each curve representing a different model run in which nourishment occurred at one location only. The curves show the human signal (with the coastline change in a nourishment-free control run subtracted), normalized for the cuspate-cape shape of the shoreline. (After Slott et al., accepted.)

Ells, K.; Murray, A. B.; Slott, J. M.

2010-12-01

300

NLP-12 engages different UNC-13 proteins to potentiate tonic and evoked release.  

PubMed

A neuropeptide (NLP-12) and its receptor (CKR-2) potentiate tonic and evoked ACh release at Caenorhabditis elegans neuromuscular junctions. Increased evoked release is mediated by a presynaptic pathway (egl-30 G?q and egl-8 PLC?) that produces DAG, and by DAG binding to short and long UNC-13 proteins. Potentiation of tonic ACh release persists in mutants deficient for egl-30 G?q and egl-8 PLC? and requires DAG binding to UNC-13L (but not UNC-13S). Thus, NLP-12 adjusts tonic and evoked release by distinct mechanisms. PMID:25609620

Hu, Zhitao; Vashlishan-Murray, Amy B; Kaplan, Joshua M

2015-01-21

301

Patterns in benthic biodiversity link lake trophic status to structure and potential function of three large, deep lakes.  

PubMed

Relative to their scarcity, large, deep lakes support a large proportion of the world's freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world's largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe's diversity is indicative of differential response of chironomid communities to nutrient enrichment which may be an indication of changes in trophic state within and across habitats. PMID:25594516

Hayford, Barbara L; Caires, Andrea M; Chandra, Sudeep; Girdner, Scott F

2015-01-01

302

Patterns in Benthic Biodiversity Link Lake Trophic Status to Structure and Potential Function of Three Large, Deep Lakes  

PubMed Central

Relative to their scarcity, large, deep lakes support a large proportion of the world’s freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world’s largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe’s diversity is indicative of differential response of chironomid communities to nutrient enrichment which may be an indication of changes in trophic state within and across habitats. PMID:25594516

Hayford, Barbara L.; Caires, Andrea M.; Chandra, Sudeep; Girdner, Scott F.

2015-01-01

303

Numerical study on the potential impact of different bottom boundary conditions on the water balance of lysimeters  

NASA Astrophysics Data System (ADS)

The SOILCan lysimeter network is a large scale climate feedback experiment and is embedded in the four long term observatories of TERENO (TERestrial ENvironmental Observatories). The focus of the SOILCan-project is to observe the impact of climate change on water and matter budgets in different grass- and arable-land lysimeters. The monitoring infrastructure was established across a rainfall and temperature transect along which lysimeters were transported from wetter to drier conditions. The lysimeters in SOILCan have a controlled bottom boundary condition using a rack of suction candles that enables upward and downward flow of water. This pressure head at the bottom is controlled by measured soil water potentials in undisturbed soil in the close vicinity of the bottom of the lysimeter. For transported lysimeters this controlling approach no longer works as the surrounding soil profile and both its upper climatic boundary conditions and lower boundary conditions related to its hydrogeological setting differ from the place where the lysimeter was taken from. In order to evaluate these artefacts and to derive a suited approach to control the lower boundary of transported lysimeters, water balance simulations were run. We analyzed three different approaches to impose bottom boundary conditions for transported lysimeters. A 'zeroth-order' approach is to define the bottom boundary at the bottom of the lysimeter and use the pressure heads measured at the location from which the soil lysimeter was taken. However, this approach is prone to artefacts since these bottom boundary conditions are determined by the climate at the site where the lysimeter was taken from. A 'first-order' approach is to define a bottom boundary condition at a certain hydrogeological boundary that can be defined deeper in the soil profile such as a seepage face or a groundwater table. However, for shallow groundwater tables, this approach may also lead to artefacts since the depth of the groundwater table may change with changing climate. In a 'second-order' approach, the effect of changing climate conditions on these bottom boundaries is evaluated. Therefore, other hydrogeological properties that determine lateral groundwater flow such as the depth of an impermeably layer and the distance between surface water structures that drain groundwater have to be considered in the approach as well. We will present a comparison of these approaches using water balance results derived by numerical simulation with the software HYDRUS 1-D.

Groh, Jannis; Vanderborght, Jan; Pütz, Thomas; Vereecken, Harry

2014-05-01

304

Copy number variation detection in cattle reveals potential breed specific differences  

Technology Transfer Automated Retrieval System (TEKTRAN)

Copy Number Variations (CNVs) are large, common deletions or duplications of genome sequence among individuals of a species that have been linked to diseases and phenotypic traits. For example, a CNV-generating, translocation mechanism encompassing the KIT gene is responsible for color sidedness in ...

305

Integrating Differences: Design Culture's Potential Impact on Contemporary Education  

ERIC Educational Resources Information Center

This qualitative study charted the implications and potentialities of embracing a design culture within contemporary education. Unlike the positivist scientific paradigm which dissects and analyzes, a design philosophy offers a unifying logic that facilitates change, acknowledges complexity, and shapes possibilities (Nelson & Stolterman,…

Uri, Therese

2012-01-01

306

Motor unit potential morphology differences in individuals with non-specific arm pain and lateral epicondylitis  

Microsoft Academic Search

BACKGROUND: The pathophysiology of non-specific arm pain (NSAP) is unclear and the diagnosis is made by excluding other specific upper limb pathologies, such as lateral epicondylitis or cervical radiculopathy. The purpose of this study was to determine: (i) if the quantitative parameters related to motor unit potential morphology and\\/or motor unit firing patterns derived from electromyographic (EMG) signals detected from

Kristina M Calder; Daniel W Stashuk; Linda McLean

2008-01-01

307

Groundwater pollution potential and greenhouse gas emission from soils amended with different swine biochars  

Technology Transfer Automated Retrieval System (TEKTRAN)

Although there exist numerous research studies in the literature on greenhouse gas emission and groundwater pollution potentials of soils amended with plant-based biochar made from traditional dry pyrolysis (hereafter referred as pyrochar), a very few such studies exist for hydrochar made from hydro...

308

Ecstasy and methamphetamine elicit action potential bursts via different mechanisms in a central snail neuron.  

PubMed

This study sought to determine the effects of (+) methamphetamine (METH) and its ring-substituted analog (+/-)3,4-methylenedioxymethamphetamine (MDMA; ecstasy) on electrophysiological behavior and their relationships to second messenger systems in an identifiable RP4 neuron of the African snail, Achatina fulica Ferussac. Extracellular application of MDMA at 1mM and METH at 3mM elicited action potential bursts that were not blocked after immersing the neurons in Ca(2+)-free solution. Notably, MDMA- (1mM) elicited action potential bursts were blocked by pretreatment with the protein kinase C (PKC) inhibitors chelerythrine (20 microM) and Ro 31-8220 (20 microM), but not by the PKA inhibitors KT-5720 (10 microM) and H89 (10 microM). The PKC activator phorbol 12,13-dibutyrate (PDBu; 3 microM), but not the PKA activator forskolin (50 microM), facilitated the induction of bursts elicited by MDMA at a lower concentration (0.3mM). In contrast, METH- (3mM) elicited action potential bursts were blocked by pretreatment with KT-5720 (10 microM) and H89 (10 microM), but not by chelerythrine (20 microM) and Ro 31-8220 (20 microM). Forskolin (50 microM), but not PDBu (3 microM) facilitated the induction of bursts elicited by METH at a lower concentration (1mM). Tetraethylammonium chloride (TEA), a blocker of the delayed rectifying K(+) current (I(KD)), did not elicit bursts at a concentration of 5mM but did facilitate the induction of action potential bursts elicited by both METH and MDMA. Voltage clamp studies revealed that both METH and MDMA decreased the TEA-sensitive I(KD) of the RP4 neuron. Forskolin (50 microM) or dibutyryl cAMP (1mM), a membrane-permeable cAMP analog, alone did not elicit action potential bursts. However, co-administration with forskolin (50 microM) and TEA (5mM) or co-administration with dibutyryl cAMP (1mM) and TEA (50mM) elicited action potential bursts in the presence of the PKC inhibitor chelerythrine (20 microM). Similarly, PDBu (10 microM) or phorbol 12-myristate 13-acetate (PMA; 3 microM) alone did not elicit action potential bursts. However, co-administration with PDBu (10 microM) and TEA (5mM) or co-administration with PMA (3 microM) and TEA (5mM) elicited action potential bursts in the presence of the PKA inhibitor KT-5720 (10 microM). These data suggest that action potential bursts in the RP4 neuron were not due to Ca(2+)-dependent synaptic effects. Rather, action potential bursts may be elicited through (1) combined activation of the cAMP-PKA signaling pathway and inhibition of the I(KD) and (2) combined activation of PKC and inhibition of the I(KD). PMID:19958791

Lin, Pei-Lin; Tsai, Ming-Cheng; Lu, Guan-Ling; Lu, Dah-Yuu; Chuang, Chieh-Min; Yang, Han-Yin; Huang, Shiang-Suo; Chen, Yi-Hung

2010-01-01

309

Different Frontal Involvement in ALS and PLS Revealed by Stroop Event-Related Potentials and Reaction Times  

PubMed Central

Background: A growing body of evidence suggests a link between cognitive and pathological changes in amyotrophic lateral sclerosis (ALS) and in frontotemporal lobar degeneration (FTLD). Cognitive deficits have been investigated much less extensively in primary lateral sclerosis (PLS) than in ALS. Objective: To investigate bioelectrical activity to Stroop test, assessing frontal function, in ALS, PLS, and control groups. Methods: Thirty-two non-demented ALS patients, 10 non-demented PLS patients, and 27 healthy subjects were included. Twenty-nine electroencephalography channels with binaural reference were recorded during covert Stroop task performance, involving mental discrimination of the stimuli and not vocal or motor response. Group effects on event-related potentials (ERPs) latency were analyzed using statistical multivariate analysis. Topographic analysis was performed using low-resolution brain electromagnetic tomography (LORETA). Results: Amyotrophic lateral sclerosis patients committed more errors in the execution of the task but they were not slower, whereas PLS patients did not show reduced accuracy, despite a slowing of reaction times (RTs). The main ERP components were delayed in ALS, but not in PLS, compared with controls. Moreover, RTs speed but not ERP latency correlated with clinical scores. ALS had decreased frontotemporal activity in the P2, P3, and N4 time windows compared to controls. Conclusion: These findings suggest a different pattern of psychophysiological involvement in ALS compared with PLS. The former is increasingly recognized to be a multisystems disorder, with a spectrum of executive and behavioral impairments reflecting frontotemporal dysfunction. The latter seems to mainly involve the motor system, with largely spared cognitive functions. Moreover, our results suggest that the covert version of the Stroop task used in the present study, may be useful to assess cognitive state in the very advanced stage of the disease, when other cognitive tasks are not applicable. PMID:24376417

Amato, Ninfa; Riva, Nilo; Cursi, Marco; Martins-Silva, Ana; Martinelli, Vittorio; Comola, Mauro; Fazio, Raffaella; Comi, Giancarlo; Leocani, Letizia

2013-01-01

310

Growth, stomatal resistance, and transpiration of Aloe vera under different soil water potentials  

Microsoft Academic Search

Aloe vera (Sábila) is used in folklore medicine and commercial cosmetology products in many countries. Little is known about the plant's physiological, growth, and yield responses under different irrigation regimes. The plant has a crassulacean acid metabolism (CAM) that allows water conservation within the tissue, and therefore, resistance to high water stress. A. vera plants were submitted to different irrigation

R. Rodríguez-García; D. Jasso de Rodríguez; J. A. Gil-Marín; J. L. Angulo-Sánchez; R. H. Lira-Saldivar

2007-01-01

311

Proficiency Differences in Syntactic Processing of Monolingual Native Speakers Indexed by Event-Related Potentials  

ERIC Educational Resources Information Center

Although anecdotally there appear to be differences in the way native speakers use and comprehend their native language, most empirical investigations of language processing study university students and none have studied differences in language proficiency, which may be independent of resource limitations such as working memory span. We examined…

Pakulak, Eric; Neville, Helen J.

2010-01-01

312

Isolated rat hepatocytes in suspension: Potential hepatotoxic effects of six different drugs  

Microsoft Academic Search

Isolated rat hepatocytes in suspension were studied with regard to various measures of hepatic toxicity. We compared enzyme leakage (ASAT, ALAT, LDH), cell viability (trypan blue exclusion), intracellular ATP content, and incorporation of 14C-valine into stationary and export proteins while the cells were exposed to six different drugs at two different concentrations. The drugs were oxytetracycline, paracetamol, carbon tetrachloride, ethanol,

Barthold Vonen; Jørg Mørland

1984-01-01

313

Potential Large Animal Models for Gene Therapy of Human Genetic Diseases of Immune and Blood Cell Systems  

PubMed Central

Genetic mutations involving the cellular components of the hematopoietic system—red blood cells, white blood cells, and platelets—manifest clinically as anemia, infection, and bleeding. Although gene targeting has recapitulated many of these diseases in mice, these murine homologues are limited as translational models by their small size and brief life span as well as the fact that mutations induced by gene targeting do not always faithfully reflect the clinical manifestations of such mutations in humans. Many of these limitations can be overcome by identifying large animals with genetic diseases of the hematopoietic system corresponding to their human disease counterparts. In this article, we describe human diseases of the cellular components of the hematopoietic system that have counterparts in large animal species, in most cases carrying mutations in the same gene (CD18 in leukocyte adhesion deficiency) or genes in interacting proteins (DNA cross-link repair 1C protein and protein kinase, DNA-activated, catalytic polypeptide in radiation-sensitive severe combined immunodeficiency). Furthermore, we describe the potential of these animal models to serve as disease-specific, preclinical models for testing the efficacy and safety of clinical interventions such as hematopoietic stem cell transplantation or gene therapy approaches before their use in humans with the corresponding disease. PMID:19293460

Bauer, Thomas R.; Adler, Rima L.; Hickstein, Dennis D.

2009-01-01

314

Linkages between microbial functional potential and wastewater constituents in large-scale membrane bioreactors for municipal wastewater treatment.  

PubMed

Large-scale membrane bioreactors (MBRs) have been widely used for the municipal wastewater treatment, whose performance relies on microbial communities of activated sludge. Nevertheless, microbial functional structures in MBRs remain little understood. To gain insight into functional genes and their steering environmental factors, we adopted GeoChip, a high-throughput microarray-based tool, to examine microbial genes in four large-scale, in-operation MBRs located in Beijing, China. The results revealed substantial microbial gene heterogeneity (43.7-85.1% overlaps) among different MBRs. Mantel tests indicated that microbial nutrient cycling genes were significantly (P < 0.05) correlated to influent COD, [Formula: see text] -N, TP or sulfate, which signified the importance of microbial mediation of wastewater constituent removal. In addition, functional genes shared by all four MBRs contained a large number of genes involved in antibiotics resistance, metal resistance and organic remediation, suggesting that they were required for degradation or resistance to toxic compounds in wastewater. The linkages between microbial functional structures and environmental variables were also unveiled by the finding of hydraulic retention time, influent COD, [Formula: see text] -N, mixed liquid temperature and humic substances as major factors shaping microbial communities. Together, the results presented demonstrate the utility of GeoChip-based microarray approach in examining microbial communities of wastewater treatment plants and provide insights into the forces driving important processes of element cycling. PMID:24675272

Sun, Yanmei; Shen, Yue-xiao; Liang, Peng; Zhou, Jizhong; Yang, Yunfeng; Huang, Xia

2014-06-01

315

Role of the outer pore domain in transient receptor potential vanilloid 1 dynamic permeability to large cations.  

PubMed

Transient receptor potential vanilloid 1 (TRPV1) has been shown to alter its ionic selectivity profile in a time- and agonist-dependent manner. One hallmark of this dynamic process is an increased permeability to large cations such as N-methyl-d-glucamine (NMDG). In this study, we mutated residues throughout the TRPV1 pore domain to identify loci that contribute to dynamic large cation permeability. Using resiniferatoxin (RTX) as the agonist, we identified multiple gain-of-function substitutions within the TRPV1 pore turret (N628P and S629A), pore helix (F638A), and selectivity filter (M644A) domains. In all of these mutants, maximum NMDG permeability was substantially greater than that recorded in wild type TRPV1, despite similar or even reduced sodium current density. Two additional mutants, located in the pore turret (G618W) and selectivity filter (M644I), resulted in significantly reduced maximum NMDG permeability. M644A and M644I also showed increased and decreased minimum NMDG permeability, respectively. The phenotypes of this panel of mutants were confirmed by imaging the RTX-evoked uptake of the large cationic fluorescent dye YO-PRO1. Whereas none of the mutations selectively altered capsaicin-induced changes in NMDG permeability, the loss-of-function phenotypes seen with RTX stimulation of G618W and M644I were recapitulated in the capsaicin-evoked YO-PRO1 uptake assay. Curiously, the M644A substitution resulted in a loss, rather than a gain, in capsaicin-evoked YO-PRO1 uptake. Modeling of our mutations onto the recently determined TRPV1 structure revealed several plausible mechanisms for the phenotypes observed. We conclude that side chain interactions at a few specific loci within the TRPV1 pore contribute to the dynamic process of ionic selectivity. PMID:25568328

Munns, Clare H; Chung, Man-Kyo; Sanchez, Yuly E; Amzel, L Mario; Caterina, Michael J

2015-02-27

316

A large prospective study of meat consumption and colorectal cancer risk: an investigation of potential mechanisms underlying this association  

PubMed Central

Although the relation between red and processed meat intake and colorectal cancer has been reported in several epidemiologic studies, very few investigated the potential mechanisms. This study examined multiple potential mechanisms in a large U.S. prospective cohort with a detailed questionnaire on meat type and meat cooking methods linked to databases for estimating intake of mutagens formed in meats cooked at high temperatures (heterocyclic amines, polycyclic aromatic hydrocarbons), heme iron, nitrate and nitrite. During 7 years of follow-up, 2,719 colorectal cancer cases were ascertained from a cohort of 300,948 men and women. The hazard ratios (HR) and 95% confidence intervals (CI) comparing the fifth to the first quintile for both red (HR=1.24, 95% CI: 1.09-1.42; p-trend <0.001) and processed meat (HR=1.16, 95% CI: 1.01-1.32; p-trend=0.017) intake indicated an elevated risk for colorectal cancer. The potential mechanisms for this relation include heme iron (HR=1.13, 95% CI: 0.99-1.29; p-trend=0.022), nitrate from processed meats (HR=1.16, 95% CI: 1.02-1.32; p-trend=0.001) and heterocyclic amine intake (HR=1.19, 95% CI: 1.05-1.34; p-trend <0.001 for MeIQx and HR=1.17, 95% CI: 1.05-1.29; p-trend <0.001 for DiMeIQx). In general, the elevated risks were higher for rectal cancer than for colon cancer, with the exception of MeIQx and DiMeIQx, which were only associated with colon cancer. In conclusion, we found a positive association for red and processed meat intake and colorectal cancer; heme iron, nitrate/nitrite, and heterocyclic amines from meat may explain these associations. PMID:20215514

Cross, Amanda J.; Ferrucci, Leah M.; Risch, Adam; Graubard, Barry I .; Ward, Mary H.; Park, Yikyung; Hollenbeck, Albert R.; Schatzkin, Arthur; Sinha, Rashmi

2010-01-01

317

Differences in population dynamics and potential impacts of a freshwater invader driven by temporal habitat stability  

Microsoft Academic Search

Understanding population dynamics and population regulation of invasive species is critical for predicting their effects on\\u000a native ecosystems as well as for control strategies. Many species of gastropod in the genus Pomacea are successful aquatic invaders that have caused economic and ecological impacts in Southeastern Asia where their large fecundity\\u000a and broad reproductive window helps them to colonize and take

Lyubov E. Burlakova; Dianna K. Padilla; Alexander Y. Karatayev; David N. Hollas; Leah D. Cartwright; Kevin D. Nichol

2010-01-01

318

Ecstasy and methamphetamine elicit action potential bursts via different mechanisms in a central snail neuron  

Microsoft Academic Search

This study sought to determine the effects of (+) methamphetamine (METH) and its ring-substituted analog (±)3,4-methylenedioxymethamphetamine (MDMA; ecstasy) on electrophysiological behavior and their relationships to second messenger systems in an identifiable RP4 neuron of the African snail, Achatina fulica Ferussac. Extracellular application of MDMA at 1mM and METH at 3mM elicited action potential bursts that were not blocked after immersing

Pei-Lin Lin; Ming-Cheng Tsai; Guan-Ling Lu; Dah-Yuu Lu; Chieh-Min Chuang; Han-Yin Yang; Shiang-Suo Huang; Yi-Hung Chen

2010-01-01

319

Nitrogen mineralization potentials of shrub-steppe soils with different disturbance histories  

Microsoft Academic Search

Disturbance of shrub-steppe soils and changes in the dominant plant cover may alter soil N-cycling processes. The mineralization of organic N to plant-available forms is an important component of the N cycle in shrub-steppe soils. Therefore, the soil N-mineralization potential (N{sub o}) was determined for two arid ecosystems, an undisturbed perennial shrub-steppe and an annual grassland, which was initially shrub-steppe

H. Jr. Bolton; R. E. Wildung; J. L. Smith

2009-01-01

320

Dimensional overlap between arrows as cueing stimuli and responses? : evidence from contra-ipsilateral differences in EEG potentials  

Microsoft Academic Search

In the S1–S2 interval, 400 ms after an arrow as S1, an EEG-potential difference occurs between scalp sites contralateral and ipsilateral to arrow direction. Eimer [J. Exp. Psychol. Hum. Percept. Perform. 21 (1995) 837–854] interpreted this difference as a sign of automatic activation of the manual response, due to dimensional overlap of arrows and responses. However, according to Kornblum et

R. Verleger; C. Vollmer; B. Wauschkuhn; Lubbe van der R. H. J; E. Wascher

2000-01-01

321

A Large-Scale Investigation of Lateralization in Cortical Anatomy and Word Reading: Are There Sex Differences?  

PubMed Central

Although left hemisphere language specialization is one of the most widely reported findings in human neuropsychology, some studies have found evidence for more bilateral language organization in women. We report findings of a large scale, multi-task investigation of sex differences in both structural asymmetries and lateralization of word reading. Two hundred participants were tested in eight divided visual field lexical tasks, and each received a structural MRI scan. We examined whether there was evidence for sex differences in overall measures of neuroanatomical and behavioral lateralization, in specific language tasks and brain regions, and in variation in asymmetry within and across tasks and brain regions. There was very little evidence for sex differences on any behavioral measure. The few indications of sex differences in the current report accounted for 2% or less of the individual variation in asymmetry and could not be replicated in independent subsamples. No sex differences were observed in the asymmetry of structures in Broca’s and Wernicke’s area such as pars triangularis, pars opercularis, the planum temporale, planum parietale, or Heschl’s gyrus. There were also no sex differences in the variability of neuroanatomical asymmetries within or between brain regions. However, a significant relationship between planum temporale and behavioral asymmetry was restricted to men. PMID:19254094

Chiarello, Christine; Welcome, Suzanne E.; Halderman, Laura K.; Towler, Stephen; Julagay, Janelle; Otto, Ronald; Leonard, Christiana M.

2011-01-01

322

Evaluation of anticancer potential of sorghums with different genetic characteristics and levels of phenolic compounds  

E-print Network

inhibition (near 100%) in mammary, colon and liver cancer cell lines. Sumac sorghum bran was selected for further investigation. Methanolic extracts from sumac whole grain, bran and tannin removed bran were tested in vitro at different concentrations...

Guajardo Flores, Sara

2009-05-15

323

Onset Dynamics of Action Potentials in Rat Neocortical Neurons and Identified Snail Neurons: Quantification of the Difference  

PubMed Central

The generation of action potentials (APs) is a key process in the operation of nerve cells and the communication between neurons. Action potentials in mammalian central neurons are characterized by an exceptionally fast onset dynamics, which differs from the typically slow and gradual onset dynamics seen in identified snail neurons. Here we describe a novel method of analysis which provides a quantitative measure of the onset dynamics of action potentials. This method captures the difference between the fast, step-like onset of APs in rat neocortical neurons and the gradual, exponential-like AP onset in identified snail neurons. The quantitative measure of the AP onset dynamics, provided by the method, allows us to perform quantitative analyses of factors influencing the dynamics. PMID:18398478

Volgushev, Maxim; Malyshev, Aleksey; Balaban, Pavel; Chistiakova, Marina; Volgushev, Stanislav; Wolf, Fred

2008-01-01

324

Onset dynamics of action potentials in rat neocortical neurons and identified snail neurons: quantification of the difference.  

PubMed

The generation of action potentials (APs) is a key process in the operation of nerve cells and the communication between neurons. Action potentials in mammalian central neurons are characterized by an exceptionally fast onset dynamics, which differs from the typically slow and gradual onset dynamics seen in identified snail neurons. Here we describe a novel method of analysis which provides a quantitative measure of the onset dynamics of action potentials. This method captures the difference between the fast, step-like onset of APs in rat neocortical neurons and the gradual, exponential-like AP onset in identified snail neurons. The quantitative measure of the AP onset dynamics, provided by the method, allows us to perform quantitative analyses of factors influencing the dynamics. PMID:18398478

Volgushev, Maxim; Malyshev, Aleksey; Balaban, Pavel; Chistiakova, Marina; Volgushev, Stanislav; Wolf, Fred

2008-01-01

325

Hemispheric Differences in the Time-Course of Semantic Priming Processes: Evidence from Event-Related Potentials (ERPs)  

ERIC Educational Resources Information Center

To investigate hemispheric differences in the timing of word priming, the modulation of event-related potentials by semantic word relationships was examined in each cerebral hemisphere. Primes and targets, either categorically (silk-wool) or associatively (needle-sewing) related, were presented to the left or right visual field in a go/no-go…

Bouaffre, Sarah; Faita-Ainseba, Frederique

2007-01-01

326

Effects of muscle potential depression and muscle stimulation caused by different insulation coating configurations on cardiac pacemakers  

Microsoft Academic Search

Insulation coating was added to the external pacemaker surface to prevent unnecessary electric current leakage to the periphery because the pulse generator body is used as an anode in unipolar pacing. However, a model without insulation coating has recently been used, so we studied the effects on muscle potential inhibition and muscle stimulation of pacemakers in unipolar pacing with different

Toshimi Yajima; Kenichi Yamada; Naoko Okubo; Takashi Nitta; Masami Ochi; Kazuo Shimizu

2005-01-01

327

Improving Students' Ability to Intuitively Infer Resistance from Magnitude of Current and Potential Difference Information: A Functional Learning Approach  

ERIC Educational Resources Information Center

The study examined the knowledge of the functional relations between potential difference, magnitude of current, and resistance among seventh graders, ninth graders, 11th graders (in technical schools), and college students. It also tested the efficiency of a learning device named "functional learning" derived from cognitive psychology on the…

Chasseigne, Gerard; Giraudeau, Caroline; Lafon, Peggy; Mullet, Etienne

2011-01-01

328

The transepithelial potential difference in the gills of the fiddler crab, Uca tangeri: Influence of some inhibitors  

Microsoft Academic Search

Euryhaline Crustacea living in dilute media, counterbalance the salt loss by active absorption of NaCl across the gill epithelium. To investigate the mechanisms involved in salt absorption, transeptithelial potential difference (PDte) was measured in isolated, perfused gills of the fiddler crab,Uca tangeri. The influence of some specific inhibitors of epithelial ion transport on the PDte was tested.

Gisela Drews; Kai Graszynski

1987-01-01

329

Effect of Noise from DC-Driven Trains to Geoelectrical Potential Difference and its Reduction in Hakuba Area, Japan  

NASA Astrophysics Data System (ADS)

The variations of geoelectrical potential differences in Hakuba area, Nagano Prefecture, Japan have been investigated. The noises originated from the DC-driven trains were found to contaminate the natural geoelectrical potential data. The most intense influence of trains occurred when the train was running nearby measuring dipoles. The gradient of the potential was deflected towards the railways and/or the position of the train, exhibiting a certain correlation between the power supply data at substation and the geoelectrical potential data at measuring sites. Extracting the high correlation part (r > 0.7), “idealized” train noise can be computed by the least square method. The reduction of train noise by more than 60 % was achieved by subtracting the idealized noise from observed data.

Ishikawa, Hisashi; Hattori, Katsumi; Takahashi, Ichiro; Noda, Yoichi; Nagao, Toshiyasu; Isezaki, Nobuhiro

330

Redox potential of pheophytin a in photosystem II of two cyanobacteria having the different special pair chlorophylls  

PubMed Central

Water oxidation by photosystem (PS) II in oxygenic photosynthetic organisms is a major source of energy on the earth, leading to the production of a stable reductant. Mechanisms generating a high oxidation potential for water oxidation have been a major focus of photosynthesis research. This potential has not been estimated directly but has been measured by the redox potential of the primary electron acceptor, pheophytin (Phe) a. However, the reported values for Phe a are still controversial. Here, we measured the redox potential of Phe a under physiological conditions (pH 7.0; 25 °C) in two cyanobacteria with different special pair chlorophylls (Chls): Synechocystis sp. PCC 6803, whose special pair for PS II consists of Chl a, and Acaryochloris marina MBIC 11017, whose special pair for PS II consists of Chl d. We obtained redox potentials of ?536 ± 8 mV for Synechocystis sp. PCC 6803 and ?478 ± 24 mV for A. marina on PS II complexes in the presence of 1.0 M betaine. The difference in the redox potential of Phe a between the two species closely corresponded with the difference in the light energy absorbed by Chl a versus Chl d. We estimated the potentials of the special pair of PS II to be 1.20 V and 1.18 V for Synechocystis sp. PCC 6803 (P680) and A. marina (P713), respectively. This clearly indicates conservation in the properties of water-oxidation systems in oxygenic photosynthetic organisms, irrespective of the special-pair chlorophylls. PMID:20142495

Allakhverdiev, Suleyman I.; Tomo, Tatsuya; Shimada, Yuichiro; Kindo, Hayato; Nagao, Ryo; Klimov, Vyacheslav V.; Mimuro, Mamoru

2010-01-01

331

Potential explanation of limb combination performance differences for two-limb coordination tasks  

PubMed Central

Rhythmic two-limb coordinated movements in the sagittal plane are variable and inaccurate when the movements are in the opposite direction as compared with those in the same direction (directional constraint). The magnitude of directional constraint depends on the particular limb combination. It is prominent in ipsilateral hand-foot coordination, but minimal in bimanual hand coordination. The reason for such differences remains unclear. In this study, we investigated the possible mechanisms underlying the production of the difference that depend on limb combination. Subjects performed two-limb rhythmic coordinated movements either in the same or in the opposite direction for three separate limb combinations (bilateral hands, contralateral hand and foot, and ipsilateral hand and foot). For each combination two different tasks were performed. In the first condition, subjects actively moved two limbs (active condition). Second, subjects actively moved one limb in coordination with a passively moved limb (passive condition). In the active condition, the directional constraint was dependent upon the limb combination, as reported in previous studies; the directional constraint was quite prominent in ipsilateral combinations, intermediate in contralateral combinations, and minimal for bilateral combination. However, differences in the directional constraint did not depend on limb combination for any combination in the passive conditions which apparently utilized closed-loop control. In other word, the difference depending on limb combination disappeared when control strategies become uniformly closed-loop. Thus, we speculate that the control strategy utilized depends on limb combination in the active condition. Additionally, different mechanisms other than closed-loop control also would have influence depending on the particular limb combination. This may result in differences in performance depending upon the limb combination. PMID:25713327

Nakagawa, Kento; Muraoka, Tetsuro; Kanosue, Kazuyuki

2015-01-01

332

Potential explanation of limb combination performance differences for two-limb coordination tasks.  

PubMed

Rhythmic two-limb coordinated movements in the sagittal plane are variable and inaccurate when the movements are in the opposite direction as compared with those in the same direction (directional constraint). The magnitude of directional constraint depends on the particular limb combination. It is prominent in ipsilateral hand-foot coordination, but minimal in bimanual hand coordination. The reason for such differences remains unclear. In this study, we investigated the possible mechanisms underlying the production of the difference that depend on limb combination. Subjects performed two-limb rhythmic coordinated movements either in the same or in the opposite direction for three separate limb combinations (bilateral hands, contralateral hand and foot, and ipsilateral hand and foot). For each combination two different tasks were performed. In the first condition, subjects actively moved two limbs (active condition). Second, subjects actively moved one limb in coordination with a passively moved limb (passive condition). In the active condition, the directional constraint was dependent upon the limb combination, as reported in previous studies; the directional constraint was quite prominent in ipsilateral combinations, intermediate in contralateral combinations, and minimal for bilateral combination. However, differences in the directional constraint did not depend on limb combination for any combination in the passive conditions which apparently utilized closed-loop control. In other word, the difference depending on limb combination disappeared when control strategies become uniformly closed-loop. Thus, we speculate that the control strategy utilized depends on limb combination in the active condition. Additionally, different mechanisms other than closed-loop control also would have influence depending on the particular limb combination. This may result in differences in performance depending upon the limb combination. PMID:25713327

Nakagawa, Kento; Muraoka, Tetsuro; Kanosue, Kazuyuki

2015-02-01

333

On the relationship between the tree and its environment, based on electrical potential difference monitoring on trunk of trees  

NASA Astrophysics Data System (ADS)

Electrical potential differences (EPD) in the trunk of a Turkey oak tree (measured by using non-polarising electrodes deepened in the sap wood) have been continuously recorded in the Geophysical Observatory "Istv n Széchenyi" of the Hungarian Academy of Sciences since 1997. Besides of various geophysical observations, meteorological and direct sap-flow measurements have also been carried out in the observatory. As it was found (Kopp n A., Szarka L., Wesztergom V., 2000: Annual fluctuation in amplitudes of daily variations of electrical signals measured in the trunk of a standing tree. C.R. Acad. Sci. Paris, Life Sciences 323, 559-563), the measured electric potential difference data have a characteristic sinusoidal daily fluctuation, and the intensity of the diurnal variations has a double-peak annual characteristics, which coincides with the life activity maximums of the tree. We have found a remarkable inter-correlation between trunk EPD, water potential of air (derived from meteorological data), and direct sap flow velocity data from a neighboring tree. All these results clearly demonstrate that the sap streaming due to the transpiration and root pressure generates the largest part of measured potential differences. The ratio of the flow velocity of a diluted solution forced through stems and the potential differences was found to be constant (Gindl, W., L”ppert, H.-G., Wimmer, R., 1999: Relationship between streaming potential and sap velocity in Salix alba L. Phyton, 39, 217-224.). On the contrary in our in-vivo experiments the relationship between the measured sap flow velocity and EPD is non-linear, which means that the conductivity (i.e. ion concentration) of the xylem sap itself also has a daily fluctuation.

Koppan, A.; Fenyvesi, A.; Szarka, L.; Wesztergom, V.

2002-05-01

334

Identification of Different Types of Spinal Afferent Nerve Endings That Encode Noxious and Innocuous Stimuli in the Large Intestine Using a Novel Anterograde Tracing Technique  

PubMed Central

In mammals, sensory stimuli in visceral organs, including those that underlie pain perception, are detected by spinal afferent neurons, whose cell bodies lie in dorsal root ganglia (DRG). One of the major challenges in visceral organs has been how to identify the different types of nerve endings of spinal afferents that transduce sensory stimuli into action potentials. The reason why spinal afferent nerve endings have been so challenging to identify is because no techniques have been available, until now, that can selectively label only spinal afferents, in high resolution. We have utilized an anterograde tracing technique, recently developed in our laboratory, which facilitates selective labeling of only spinal afferent axons and their nerve endings in visceral organs. Mice were anesthetized, lumbosacral DRGs surgically exposed, then injected with dextran-amine. Seven days post-surgery, the large intestine was removed. The characteristics of thirteen types of spinal afferent nerve endings were identified in detail. The greatest proportion of nerve endings was in submucosa (32%), circular muscle (25%) and myenteric ganglia (22%). Two morphologically distinct classes innervated myenteric ganglia. These were most commonly a novel class of intraganglionic varicose endings (IGVEs) and occasionally rectal intraganglionic laminar endings (rIGLEs). Three distinct classes of varicose nerve endings were found to innervate the submucosa and circular muscle, while one class innervated internodal strands, blood vessels, crypts of lieberkuhn, the mucosa and the longitudinal muscle. Distinct populations of sensory endings were CGRP-positive. We present the first complete characterization of the different types of spinal afferent nerve endings in a mammalian visceral organ. The findings reveal an unexpectedly complex array of different types of primary afferent endings that innervate specific layers of the large intestine. Some of the novel classes of nerve endings identified must underlie the transduction of noxious and/or innocuous stimuli from the large intestine. PMID:25383884

Spencer, Nick J.; Kyloh, Melinda; Duffield, Michael

2014-01-01

335

In-Season Prediction of Corn Grain Yield Potential Using Normalized Difference Vegetation Index  

Microsoft Academic Search

Drastic increases in the cost of N fertilizer and increased public scrutiny have encouraged development and implementation of im- proved N management practices. This study evaluated the relationship between corn (Zea mays L.) grain yield and early season normalized difference vegetation index (NDVI) sensor readings using the Green- Seeker sensor. The relationships between grain yield and several pre- dictor variables

R. K. Teal; B. Tubana; K. Girma; K. W. Freeman; D. B. Arnall; O. Walsh; W. R. Raun

2006-01-01

336

Potential population growth and harmful effects on humans from bed bug populations exposed to different feeding regimes.  

PubMed

Effects of host availability and feeding period on bed bugs, Cimex lectularius (L.) (Hemiptera: Cimicidae), were measured. Population growth and the potential harmful effect of bed bug populations on human hosts were modelled. Bloodmeal sizes were affected by both feeding length and frequency, with >2-fold difference between insects fed daily or weekly. Blood consumption increased >2-fold between bed bugs fed occasionally and often, and 1.5-fold between occasional and daily feeding. Bed bugs fed more often than once a week, potentially every 2-4 days. Egg production was associated with nutrition, being strongly correlated with blood consumption in the previous week. Bed bug populations can grow under different feeding regimes and are hard to control with <80% mortality. Bed bugs can survive and grow even in locations with a limited blood supply, where bed bug persistence may be important for the continual spread of populations. Persistence in non-traditional locations and a potential association with human pathogens increase the health risks of bed bugs. Potential blood loss as a result of a bed bug can have serious consequences because uncontrolled populations can reach harmful levels in 3-8 months. The reproduction potential of bed bug populations suggests serious consequences to human health and the need for efficacious control measures. PMID:23046478

Pereira, R M; Taylor, A S; Lehnert, M P; Koehler, P G

2013-06-01

337

[Visual evoked potentials and functional asymmetry in children with with different degrees of intellectual retardation].  

PubMed

Visual evoked potentials (VEP) to flash and patterned visual stimuli have been recorded from occipital and central brain regions in 7-8-year-old boys with normal intellect (20 cases), with mental retardation (15 cases) and with oligophrenia of a debile degree (27 cases). A significant elongation of late-component latency has been revealed in motor brain areas VEP in oligophrenia group compared to normal subjects. A negative correlation between P190 component latency of motor area VEP to patterned visual stimulus and general and non-verbal intellectual indices has been stated in full right-handed subjects with intellectual deficiency. Such a relation was absent in right-handed patients with left dominant eye. PMID:8042397

Katargina, T A; Kryzhanovskaia, I L; Petrova, M A

1993-01-01

338

One-dimensional modeling of a recent Ganga avulsion: Assessing the potential effect of tectonic subsidence on a large river  

NASA Astrophysics Data System (ADS)

River avulsion as studied in small-sized and medium-sized rivers is partly explained by the water surface gradient advantage of a new channel course over the old course, caused by spatial differences in aggradation and compaction. Recently, the effect of meandering upstream of the avulsion node, or bifurcation, was shown to have an equally large effect on avulsion duration as gradient advantage. These effects remain poorly understood for the largest rivers on Earth, where gradients are very small, subtle gradient advantages are affected by tectonics, and often several anabranches remain active simultaneously. Our objective was to assess the relative importance of these factors in the River Ganga in determining the pacing of an avulsion. We used a combination of historical data, remote sensing, and one-dimensional modeling. The course of the Ganga in historical times was through the present Ganga-Bhagirathi system but then there was either a gradual or sudden shift to the present Ganga-Padma system. Historical evidence and remnant paleochannels, as observed in satellite sensor data, corroborate the changing pattern of the Ganga River system, but the exact causes of the shifting and of the short avulsion duration remain unclear. Based on generalized data, using a one-dimensional model we ran idealized scenarios bracketing different tectonic subsidence estimates for long-term morphodynamic evolution of the upstream channel and the two downstream bifurcates. The model predicts flow and sediment partitioning at the bifurcation node, and includes the effect of migrating meanders at the bifurcation and width adjustment of the bifurcates. Our modeling demonstrates that the old and the new branches can remain ‘open' and morphologically active for a long time because of the large backwater effect and the high mobility of the sediment. The bifurcation stabilizes at an asymmetrical flow and sediment division, which in smaller rivers (such as the River Rhine) would be followed by residual channel filling but in the much larger Ganges results in morphologically active anabranches. The model results reveal that neither a gradient advantage nor a bend upstream of the bifurcation leads to an avulsion within centuries as has been observed in some large rivers in tectonically inactive regions. On the other hand, a realistic tectonic uplift of the old branch or subsidence of the new branch may force an avulsion to take place quickly, and historical data show that the study area is seismically active. The combination of these factors leads to a realistic modeled avulsion duration of less than three centuries. Historical data indicate that these general conclusions might also apply to other large rivers in this region, e.g. the Brahmaputra and the Teesta. We conclude that large rivers may avulse quickly in response to tectonics but attain an anabranching pattern because of the large dimension of the residual channel and backwater effects.

Gupta, Niladri; Kleinhans, Maarten G.; Addink, Elisabeth A.; Atkinson, Peter M.; Carling, Paul A.

2014-05-01

339

Potential Effects of Climate Change on the Water Level, Flora and Macro-fauna of a Large Neotropical Wetland  

PubMed Central

Possible consequences of climate change in one of the world’s largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades. PMID:23874446

Úbeda, Bárbara; Di Giacomo, Adrian S.; Neiff, Juan José; Loiselle, Steven A.; Guadalupe Poi, Alicia S.; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

2013-01-01

340

Potential effects of climate change on the water level, flora and macro-fauna of a large neotropical wetland.  

PubMed

Possible consequences of climate change in one of the world's largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades. PMID:23874446

Úbeda, Bárbara; Di Giacomo, Adrian S; Neiff, Juan José; Loiselle, Steven A; Poi, Alicia S Guadalupe; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

2013-01-01

341

Potential yields and properties of oil from the hydrothermal liquefaction of microalgae with different biochemical content.  

PubMed

A range of model biochemical components, microalgae and cyanobacteria with different biochemical contents have been liquefied under hydrothermal conditions at 350 °C, ?200 bar in water, 1M Na(2)CO(3) and 1M formic acid. The model compounds include albumin and a soya protein, starch and glucose, the triglyceride from sunflower oil and two amino acids. Microalgae include Chlorella vulgaris,Nannochloropsis occulata and Porphyridium cruentum and the cyanobacteria Spirulina. The yields and product distribution obtained for each model compound have been used to predict the behaviour of microalgae with different biochemical composition and have been validated using microalgae and cyanobacteria. Broad agreement is reached between predictive yields and actual yields for the microalgae based on their biochemical composition. The yields of bio-crude are 5-25 wt.% higher than the lipid content of the algae depending upon biochemical composition. The yields of bio-crude follow the trend lipids>proteins>carbohydrates. PMID:20599375

Biller, P; Ross, A B

2011-01-01

342

Waveform difference between skin conductance and skin potential responses in relation to electrical and evaporative properties of skin.  

PubMed

The shapes of skin conductance (SC) and skin potential (SP) responses are often similar, but can also be very different due to an unexplained cause. Using a new method to measure SC and SP simultaneously at the same electrode, this difference was investigated in a new way by comparing their temporal peak differences. SC, SP, skin susceptance (SS), and transepidermal water loss (TEWL) were recorded from 40 participants during relaxation and stress. The SP response could peak anywhere between the onset of an SC response to some time after the peak of an SC response. This peak time difference was associated with the magnitude of the SCR, the hydration of the skin, and the filling of the sweat ducts. Interpretation of the results in light of existing biophysical theories suggests that this peak difference may indicate the hydraulic capacity state of the sweat ducts at the time of a response. PMID:23889171

Tronstad, Christian; Kalvøy, Håvard; Grimnes, Sverre; Martinsen, Ørjan G

2013-11-01

343

Cytotoxic and genotoxic potential of drinking water: a comparison between two different concentration methods.  

PubMed

The level of exposure to hazardous compounds through drinking water is low but it is maintained throughout life, therefore representing a risk factor for human health. The use of techniques averaging the consumer's exposure over time could be more useful than relying on intermittent grab samples that may misrepresent average tap water concentrations due to short-term temporal variability. In this study, we compared the induction of in vitro cytotoxic and genotoxic effects (DNA damage by the comet assay) in relation to different sampling methods, i.e. exposure over time (semipermeable membrane devices, SPMDs, exposed for 30 days) or intermittent grab samples (5 weekly water sampling, C18 concentration). Waters with different chemical characteristics were sampled to test the sensitivity of the two methods. We did not found any positive correlation between the biological findings and water chemical parameters. SPMD extracts induced a significantly greater DNA damage than C18. The different behaviour was specially found for the water samples with a low level of organic compounds and when C18 extracts were highly cytotoxic. Our findings suggest that SPMD could be of a great interest in assessing genotoxic contaminants in both raw and drinking water, with great suitability for continuous monitoring. Furthermore, the results of this study have confirmed the great importance of the biological assays in evaluating the effects of a complex mixture such as water in addition to the conventional chemical examination of water quality. PMID:18199468

Buschini, Annamaria; Giordani, Federica; Pellacani, Claudia; Rossi, Carlo; Poli, Paola

2008-04-01

344

Two highly homologous phospholipase D isoenzymes from Papaver somniferum L. with different transphosphatidylation potential.  

PubMed

The genes of two phospholipase D (PLD) isoenzymes, PLD1 and PLD2, from poppy seedlings (2829 and 2828 bp) were completely sequenced. The two genes have 96.9% identity in the encoding region and can be assigned to the alpha-type of plant PLDs. The corresponding amino acid sequences do not contain any signal sequences. One Asn-glycosylation site, six and two phosphorylation sites for protein kinase C and tyrosine kinase, respectively, and two phosphatidylinositol-4,5-bisphosphate binding motifs could be identified. Like in most plant PLDs, two HKD motifs and one C2 domain are present. PLD1 and PLD2 have ten and nine cysteine residues. The two enzymes were expressed in E. coli and purified to homogeneity by Ca2+ ion-mediated hydrophobic interaction chromatography. The Ca2+ ion concentration needed for carrier binding of the two enzymes in chromatography as well as for optimum activity was found to be considerably higher (>100 mM) than with other alpha-type plant PLDs. Although PLD1 and PLD2 differ in eleven amino acids only, they showed remarkable differences in their transphosphatidylation activity. Two amino acid exchanges within and near the first HKD motif contribute to this difference as shown by the A349E/E352Q-variant of PLD2. PMID:16257263

Lerchner, Alexandra; Mansfeld, Johanna; Schäffner, Ines; Schöps, Regina; Beer, Helge K; Ulbrich-Hofmann, Renate

2005-12-15

345

Differences in passenger car and large truck involved crash frequencies at urban signalized intersections: an exploratory analysis.  

PubMed

The influence of intersection features on safety has been examined extensively because intersections experience a relatively large proportion of motor vehicle conflicts and crashes. Although there are distinct differences between passenger cars and large trucks-size, operating characteristics, dimensions, and weight-modeling crash counts across vehicle types is rarely addressed. This paper develops and presents a multivariate regression model of crash frequencies by collision vehicle type using crash data for urban signalized intersections in Tennessee. In addition, the performance of univariate Poisson-lognormal (UVPLN), multivariate Poisson (MVP), and multivariate Poisson-lognormal (MVPLN) regression models in establishing the relationship between crashes, traffic factors, and geometric design of roadway intersections is investigated. Bayesian methods are used to estimate the unknown parameters of these models. The evaluation results suggest that the MVPLN model possesses most of the desirable statistical properties in developing the relationships. Compared to the UVPLN and MVP models, the MVPLN model better identifies significant factors and predicts crash frequencies. The findings suggest that traffic volume, truck percentage, lighting condition, and intersection angle significantly affect intersection safety. Important differences in car, car-truck, and truck crash frequencies with respect to various risk factors were found to exist between models. The paper provides some new or more comprehensive observations that have not been covered in previous studies. PMID:24140813

Dong, Chunjiao; Clarke, David B; Richards, Stephen H; Huang, Baoshan

2014-01-01

346

Large interclone differences in melezitose secretion in the facultatively ant-tended black bean aphid Aphis fabae.  

PubMed

Many aphids are known to engage in a trophic mutualism with ants, whereby the aphids secrete sugary-rich honeydew which is collected by the ants for food, and the ants, in exchange, protect the aphids against natural enemies. Previous results, however, suggest that the production of some of the honeydew sugars, such as the ant-attractant trisaccharide melezitose, may induce an indirect cost to the aphids. This led us to believe that large differences in the nature of the secreted honeydew might exist, due to some clones capitalizing more or less on their mutualistic interaction with ants, or due to some "cheater" clones foregoing the production of particular sugars, instead taking advantage of the ant-attracting effect of other non sugar-deficient clones, co-occurring on the same plant. Here we present data on clonal variation in the composition of honeydew of the black bean aphid Aphis fabae which confirm this prediction. In particular, our results show that there was large interclone variation in the amount of glucose, melezitose and total sugar produced. The variation in the production of melezitose, however, showed particularly large differences, with 54% (7 out of 13) of the clones screened being virtually deficient for the production of this sugar, irrespective of whether the aphid colonies were ant-tended or not. The consequences of this finding in the context of the evolution and maintenance of the ant-aphid mutualism, as well as the adaptive benefits of oligosaccharide synthesis in aphids and other insects are discussed. PMID:21896277

Vantaux, A; Van den Ende, W; Billen, J; Wenseleers, T

2011-12-01

347

Large sex difference in adolescents on a timed line judgment task: attentional contributors and task relationship to mathematics.  

PubMed

Visuospatial performance, assessed with the new, group-administered Judgment of Line Angle and Position test (JLAP-13), varied with sex and mathematical competence in a group of adolescents. The JLAP-13, a low-level perceptual task, was modeled after a neuropsychological task dependent upon functioning of the posterior region of the right hemisphere [Benton et al, 1994 Contributions to Neuropsychological Assessment: A Clinical Manual (New York: Oxford University Press)]. High-school boys (N = 52) performed better than girls (N = 62), with a large effect for sex (d = 1.11). Performance increased with mathematical competence, but the sex difference did not vary significantly across different levels of mathematics coursework. On the basis of earlier work, it was predicted that male, but not female, performance in line judgment would decline with disruptions to task geometry (page frame), and that the sex difference would disappear with disruptions to geometry. These predictions were supported by a number of univariate and sex-specific analyses, although an omnibus repeated-measures analysis did not detect the predicted interaction, most likely owing to limitations in power. Thus, there is partial support for the notion that attentional predispositions or strategies may contribute to visuospatial sex differences, with males more likely than females to attend to, and rely upon, internal or external representations of task geometry. Additional support for this hypothesis may require development of new measures or experimental manipulations with more powerful geometrical disruptions. PMID:16700296

Collaer, Marcia L; Hill, Erica M

2006-01-01

348

Investigation of Phenolic Profiles, Cytotoxic Potential and Phytochemical Screening of Different Extracts of Drynaria quercifolia J. Smith (Leaves)  

PubMed Central

Purpose: The present study is aimed to evaluate phenolic profiles, cytotoxic activity and phytochemical screening of different extracts of Drynaria quercifolia leaves. Methods: The dried and powder leaves were extracted with methanol at room temperature and the concentrated methanolic extract was fractionated by the modified Kupchan partitioning method to provide pet-ether, carbon tetrachloride, chloroform and aqueous soluble fractions. Phenolic profiles were determined by using Folin-Ciocalteau reagent, which results were expressed in gallic acid equivalent (mg of GAE/g of sample). Phytochemical properties of different extractives of plant materials were tested by the method of Trease and Evans. Brine shrimp lethality bioassay was used to investigate the cytotoxic potential of D. quercifolia. Results: The phytochemical screening revealed the potent source of different phytochemical constituents on different extractives including alkaloid, glycosides, tannin, saponins, proteins and amino acids, flavonoids, triterpenes, phenols, phytosterols and carbohydrate. In the determination of phenolic profiles, different extractives showed a significant content of phenolic compounds ranging from 103.43 -132.23 mg of GAE/g of extractive. Compared to vincristine sulfate different extractives of plant materials demonstrated moderate cytotoxic potential (having LC50 of 12.45 ?g/ml, 13.02 ?g/ml 15.83 ?g/ml, 14.95 ?g/ml and 7.612 ?g/ml, respectively). Conclusion: It is concluded from this study that D. quercifolia is an excellent source of phenolic content and phytoconstitutes as well as possesses moderate cytotoxic activity. PMID:24312880

Runa, Jannatul Ferdous; Hossain, Marjan; Hasanuzzaman, Md.; Ali, Md. Ramjan

2013-01-01

349

Antioxidant potential of different melatonin-loaded nanomedicines in an experimental model of sepsis.  

PubMed

Oxidative stress has been shown to play a major role in the complex pathophysiological processes leading to organ failure during sepsis. The aim of the present research was to evaluate the effect of different melatonin nanoparticle (NP) carriers in an experimental animal model of sepsis. Poly-D,L-lactide-co-glycolide (PLGA [NP-A]) and polyethylene glycol-co-(poly-D,L-lactide-co-glycolide) (PLGA-PEG [NP-B]) were used to obtain melatonin-loaded nanocarriers (10 mg/kg). Oxidative stress was measured in tissue homogenates by measuring heme oxygenase-1 (HO-1) expression, total thiol groups and lipid hydroperoxides (LOOH). In vitro NPs showed a long lag time followed by a controlled release of melatonin. All the different melatonin formulations restored total thiol group levels to those of controls in all the examined organs, with no significant changes among them. Both melatonin NP formulations significantly decreased LOOH levels when compared with sepsis vehicle animals. The stealth formulation NP-B was able to produce a more significant reduction in LOOH levels in the heart, lung and liver when compared with NP-A. No significant changes were observed between the two NP formulations in the kidney. Interestingly, HO-1 expression was differently affected following treatment with various melatonin formulations. The NP-B formulation was more effective in inducing HO-1 protein compared with free melatonin and NP-A, with the exception of the kidney. Taken together, our results show that melatonin possesses a significant antioxidant activity during sepsis and that it is possible to improve this ability by delivering the compound with specific drug delivery systems. PMID:22728708

Li Volti, Giovanni; Musumeci, Teresa; Pignatello, Rosario; Murabito, Paolo; Barbagallo, Ignazio; Carbone, Claudia; Gullo, Antonino; Puglisi, Giovanni

2012-06-01

350

Quaternary megafans, large rivers and other avulsive systems: a potential "who is who" in the geological record  

NASA Astrophysics Data System (ADS)

A fascinating discussion has been recently calling the attention of sedimentologists and geomorphologists regarding to the dominant fluvial styles preserved in the geological record. While some authors postulate that distributary (or distributive) patterns are the most important systems likely to dominate the alluvial rock record (Weissmann et al.2010, among others) others suggest that a variety of fluvial styles are remarkably preserved in the geological record, rejecting the importance of the distributary systems (such as megafans and other like fans coastal systems) (Fielding et al, 2012 among others). However, the Quaternary record of the largest depositional tracks on Earth has been not assessed in a comparative and detailed way. Here I present results from some of the most important Quaternary areas of sedimentation of the world such as the alluvial belts of the largest rivers, the largest megafans and other impressive fluvial dominated wetlands in active tectonic basins. My study is based on field work I carried out in many of the analyzed areas, a literature review and remote sensing products. Specific examples are discussed from several rivers of the Amazon basin, the Parana River, the Mississippi River, among others. Large depositional tracks in forelands, platforms and intracratonic basins such as the Chaco, the Orinoco Llanos, the Bananal and Pantanal basin, the Ucamara depression, and the Indo-Gangetic plain, which contain a variety of complex avulsive systems and megafans, are discussed. A main conclusion is that megafans and similar distributary systems, avulsive systems with a variety of channel patterns and linear fluvial belts of major rivers, have the potential for preservation in the geological record. The scarcity of purely braided systems in large rivers is noticeable and they are mainly constrained to small-medium size channels, short length piedmont courses or related to relatively small alluvial fans. Meandering and anabranching systems are dominant in large rivers while anabranching systems are characteristic of megarivers. Despite the findings above, a remarkable challenge remains to identify characteristic facies assemblages for reconstructing large rivers, as they are not clearly identified in the geological record. The scale-size limitation of the architectural characteristics of fluvial landforms and the floodplain complexity of large systems are some of the challenges that need additional research when looking for analogs in the sedimentary record. References: Fielding, Christopher R., Ashworth, Philip J., Best, James L., Prokocki, EricW., Smith, Gregory H. Sambrook, (2012). Tributary, distributary and other fluvial patterns: What really represents the norm in the continental rock record?, Sedimentary Geology doi: 10.1016/j.sedgeo.2012.03.004 Weissmann, G.S., Hartley, A.J., Nichols, G.J., Scuderi, L.A., Olson, M., Buehler, H., Banteah, R., 2010. Fluvial form in modern continental sedimentary basins: distributive fluvial systems. Geology 38, 39-42

Latrubesse, E. M.

2012-12-01

351

Regional differences in the potential exposure of US minority populations to hazardous facilities  

SciTech Connect

In the literature that examines the distribution of environmental disamenities of various types, there is considerable documentation that minority groups and lower income groups are more likely to be exposed. Such differential exposure has been attributed to ``environmental racism`` by some authors, but there has been no systematic investigation of the factors and dynamics underlying this exposure pattern. This study examines regional differences in the proximity of African-American, Hispanics, Asians, and non-Hispanic Whites to a broad range facility types and explores the degree to which this may be related to urban and income factors.

Nieves, L.A. [Argonne National Lab., IL (United States); Nieves, A.L. [Wheaton Coll., Wheaton, IL (United States)]|[Argonne National Lab., IL (United States)

1992-12-01

352

Regional differences in the potential exposure of US minority populations to hazardous facilities  

SciTech Connect

In the literature that examines the distribution of environmental disamenities of various types, there is considerable documentation that minority groups and lower income groups are more likely to be exposed. Such differential exposure has been attributed to environmental racism'' by some authors, but there has been no systematic investigation of the factors and dynamics underlying this exposure pattern. This study examines regional differences in the proximity of African-American, Hispanics, Asians, and non-Hispanic Whites to a broad range facility types and explores the degree to which this may be related to urban and income factors.

Nieves, L.A. (Argonne National Lab., IL (United States)); Nieves, A.L. (Wheaton Coll., Wheaton, IL (United States) Argonne National Lab., IL (United States))

1992-01-01

353

Osteoinductivity potential of rhBMP-2 associated with two carriers in different dosages  

Microsoft Academic Search

The objective of this study was to evaluate bone formation after application of different doses of recombinant human bone\\u000a morphogenetic protein-2 (rhBMP-2) combined with monoolein or poloxamer gels, in critical bone defects of rats. Forty-five\\u000a Wistar rats were divided into nine treatment groups with five animals each: I: application of 1 µg rhBMP-2 + monoolein; II:\\u000a 3 µg rhBMP-2 + monoolein; III: 7 µg rhBMP-2 + monoolein; IV: 1 µg

Priscilla Maria Fernandes Abdala; Mamie Mizusaki Iyomasa; Sandra Sato; Maria Vitória Lopes Badra Bentley; Dimitrius Leonardo Pitol; Simone Cecílio Hallak Regalo; Selma Siéssere; João Paulo Mardegan Issa

2010-01-01

354

Effects of different storage protocols on cat testis tissue potential for xenografting and recovery of spermatogenesis.  

PubMed

The loss of genetic diversity due to premature death of valuable individuals is a significant problem in animal conservation programs, including endangered felids. Testis tissue xenografting has emerged as a system to obtain spermatozoa from dead immature animals, however protocols to store this tissue before xenografting are still lacking. This study focused on testis tissue cryopreservation and storage from the domestic cat (Felis catus) classified as "pre-pubertal" and "pubertal" according to spermatogenesis development. Grafts from testis tissue cryopreserved with DMSO 1.4M, recovered after 10 weeks xenografting, presented seminiferous tubules with no germ cells. On the contrary, testis tissue from pre-pubertal animals preserved in ice-cold medium for 2 to 5 days presented no loss of viability or spermatogenic potential, while the number of grafts of pubertal cat testis tissue with germ cells after 10 weeks of xenografting decreased with increasing storage time. Nevertheless, even grafts from pre-pubertal cat testis tissue presented lower anti-DDX4 and anti-BOULE staining (proteins necessary for the meiosis completion), when compared with adult cat testis. Finally, a strong correlation found between testis weight and xenograft outcome may help choose good candidates for xenografting. PMID:21958640

Mota, Paula C; Ehmcke, Jens; Westernströer, Birgit; Gassei, Kathrin; Ramalho-Santos, João; Schlatt, Stefan

2012-01-15

355

Low Plasma Leptin in Cognitively Impaired ADNI Subjects: Gender Differences and Diagnostic and Therapeutic Potential  

PubMed Central

Analysis of data derived from the Alzheimer's Disease Neuroimaging Initiative (ADNI) program showed plasma leptin levels in individuals with Mild Cognitive Impairment (MCI) or Alzheimer's disease (AD) to be lower than those of subjects with normal cognition (NC). Approximately 70% of both men and women with MCI have plasma leptin levels lower than the median values of NC. Additionally, half of these subjects carry at least one apolipoprotein-E4 (APOE-?4) allele. A subgroup of participants also had cerebrospinal fluid (CSF) leptin measured. Plasma leptin typically reflected the levels of leptin in CSF in all groups (Control/MCI/AD) in both genders. The data suggest that plasma leptin deficiency provides an indication of potential CNS leptin deficiency, further supporting the exploration of plasma leptin as a diagnostic marker for MCI or AD. The important question is whether leptin deficiency plays a role in the causation of AD and/or its progression. If this is the case, individuals with early AD or MCI with low plasma leptin may benefit from leptin replacement therapy. Thus, these data indicate that trials of leptin in low leptin MCI/early-stage AD patients should be conducted to test the hypothesis. PMID:24359504

Johnston, Jane M.; Hu, William T.; Fardo, David W.; Greco, Steven J.; Perry, George; Montine, Thomas J.; Trojanowski, John Q.; Shaw, Leslie M.; Ashford, J. Wesson; Tezapsidis, Nikolaos

2014-01-01

356

Identifying the Potential for Robotics to Assist Older Adults in Different Living Environments.  

PubMed

As the older adult population grows and becomes more diverse, so will their needs and preferences for living environments. Many adults over 65 years of age require some assistance [1, 2]; yet it is important for their feelings of well-being that the assistance not restrict their autonomy [3]. Not only is autonomy correlated with quality of life [4], autonomy enhancement may improve functionality [2, 5]. The goal of this paper is to provide guidance for the development of technology to enhance autonomy and quality of life for older adults. We explore the potential for robotics to meet these needs. We evaluated older adults' diverse living situations and the predictors of residential moves to higher levels of care in the United States. We also examined older adults' needs for assistance with activities of daily living (ADLs), instrumental activities of daily living (IADLs), and medical conditions when living independently or in a long-term care residence. By providing support for older adults, mobile manipulator robots may reduce need-driven, undesired moves from residences with lower levels of care (i.e., private homes, assisted living) to those with higher levels of care (i.e., skilled nursing). PMID:24729800

Mitzner, Tracy L; Chen, Tiffany L; Kemp, Charles C; Rogers, Wendy A

2014-04-01

357

Identifying the Potential for Robotics to Assist Older Adults in Different Living Environments  

PubMed Central

As the older adult population grows and becomes more diverse, so will their needs and preferences for living environments. Many adults over 65 years of age require some assistance [1, 2]; yet it is important for their feelings of well-being that the assistance not restrict their autonomy [3]. Not only is autonomy correlated with quality of life [4], autonomy enhancement may improve functionality [2, 5]. The goal of this paper is to provide guidance for the development of technology to enhance autonomy and quality of life for older adults. We explore the potential for robotics to meet these needs. We evaluated older adults' diverse living situations and the predictors of residential moves to higher levels of care in the United States. We also examined older adults' needs for assistance with activities of daily living (ADLs), instrumental activities of daily living (IADLs), and medical conditions when living independently or in a long-term care residence. By providing support for older adults, mobile manipulator robots may reduce need-driven, undesired moves from residences with lower levels of care (i.e., private homes, assisted living) to those with higher levels of care (i.e., skilled nursing). PMID:24729800

Mitzner, Tracy L.; Chen, Tiffany L.; Kemp, Charles C.; Rogers, Wendy A.

2014-01-01

358

Assessment of Antioxidant Potential, Total Phenolics and Flavonoids of Different Solvent Fractions of Monotheca Buxifolia Fruit  

PubMed Central

Objectives This study was conducted to investigate the antioxidant potential of methanol extract and its derived fractions (hexane, ethyl acetate, butanol, and aqueous) of fruits of Monotheca buxifolia (Falc.) Dc., a locally used fruit in Pakistan. Methods Dried powder of the fruit of M. buxifolia was extracted with methanol and the resultant was fractionated with solvents having escalating polarity; n-hexane, chloroform, ethyl acetate, n-butanol and the residual soluble aqueous fraction. Total phenolic and total flavonoid contents were estimated for the methanol and various fractions. These fractions were also subjected to various in vitro assays to estimate the scavenging activity for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), superoxide, hydroxyl, hydrogen peroxide and reductive ability for ferric ions and phosphomolybdate assay. Results The n-butanol, aqueous and methanol fractions possessed high amount of phenolics and flavonoids compared with other fractions, and subsequently showed a pronounced scavenging activity on DPPH, ABTS, superoxide, hydroxyl and hydrogen peroxide radicals and had a potent reductive ability on ferric ion and phosphomolybdate assay. There was a found significant correlation between total phenolic and flavonoid contents and EC50 of DPPH, superoxide, hydrogen peroxide radical and phosphomolybdate assays, whereas a nonsignificant correlation was found with the hydroxyl radical and ABTS radical assay. Conclusion M. buxifolia fruit can be used as natural antioxidant source to prevent damage associated with free radicals. PMID:24298440

Jan, Shumaila; Khan, Muhammad Rashid; Rashid, Umbreen; Bokhari, Jasia

2013-01-01

359

Chromium accumulation potential of Zea mays grown under four different fertilizers.  

PubMed

Chromium (Cr) contamination in soil is a growing concern in sustainable agriculture production and food safety. We performed pot experiment with chromium (30 mg/soil) to assess the accumulation potential of Zea mays and study the influence of four fertilizers, viz. Farm Yard Manure (FYM), NPK, Panchakavya (PK) and Vermicompost (VC) with respect to Cr accumulation. The oxidative stress and pigment (chlorophyll) levels were also examined. The results showed increased accumulation of chromium in both shoots and roots of Zea mays under FYM and NPK supply, and reduced with PK and VC. While the protein and pigment contents decreased in Cr treated plants, the fertilizers substantiated the loss to overcome the stress. Similarly, accumulation of Cr increased the levels of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) indicating the enhanced damage control activity. However, these levels were relatively low in plants supplemented with fertilizers. Our results confirm that the maize can play an effective role in bioremediation of soils polluted with chromium, particularly in supplementation with fertilizers such as farm yard manure and NPK. PMID:25651615

Dheeba, B; Sampathkumar, P; Kannan, K

2014-12-01

360

An investigation into the role that a transverse magnetic field plays in the formation of large anode sheath potentials  

SciTech Connect

A 9.25 A low-pressure (45{endash}55 mTorr) hollow cathode arc discharge has been used to simulate plasma processes that occur at the anode of magnetoplasmadynamic accelerators used for space propulsion applications. The interest in the near-anode region is related to findings of past research, which indicate that large anode sheath potentials can drive as much as 70{percent} of the input electrical power into the anode, thus degrading thrust efficiency. Presented here are results that essentially characterize the behavior of the near-anode plasma as a function of a transverse magnetic field. Plasma diagnostics included single Langmuir probe techniques, emission spectroscopy, and water calorimetry for anode heat flux measurements. Phenomenological arguments based on measurements taken suggest that observed changes in anode fall voltage are related to variations in the measured local electron number density as the magnetic field is varied. This behavior is attributed to the variations in the measured ionization rate, which is shown to be a nonlinear function of transverse magnetic field. {copyright} {ital 1996 American Institute of Physics.}

Foster, J.E.; Gallimore, A.D. [The Plasmadynamics and Electric Propulsion Laboratory, The University of Michigan, Ann Arbor, Michigan 48109 (United States)] [The Plasmadynamics and Electric Propulsion Laboratory, The University of Michigan, Ann Arbor, Michigan 48109 (United States)

1996-11-01

361

Large regional differences in incidence of arthroscopic meniscal procedures in the public and private sector in Denmark  

PubMed Central

Objectives A recent study reported a large increase in the number of meniscal procedures from 2000 to 2011 in Denmark. We examined the nation-wide distribution of meniscal procedures performed in the private and public sector in Denmark since different incentives may be present and the use of these procedures may differ from region to region. Setting We included data on all patients who underwent an arthroscopic meniscal procedure performed in the public or private sector in Denmark. Participants Data were retrieved from the Danish National Patient Register on patients who underwent arthroscopic meniscus surgery as a primary or secondary procedure in the years 2000 to 2011. Hospital identification codes enabled linkage of performed procedures to specific hospitals. Primary and secondary outcome measures Yearly incidence of meniscal procedures per 100?000 inhabitants was calculated with 95% CIs for public and private procedures for each region. Results Incidence of meniscal procedures increased at private and at public hospitals. The private sector accounted for the largest relative and absolute increase, rising from an incidence of 1 in 2000 to 98 in 2011. In 2011, the incidence of meniscal procedures was three times higher in the Capital Region than in Region Zealand. Conclusions Our study identified a large increase in the use of meniscal procedures in the public and private sector in Denmark. The increase was particularly conspicuous in the private sector as its proportion of procedures performed increased from 1% to 32%. Substantial regional differences were present in the incidence and trend over time of meniscal procedures. PMID:25712820

Hare, Kristoffer Borbjerg; Vinther, Jesper Høeg; Lohmander, L Stefan; Thorlund, Jonas Bloch

2015-01-01

362

Metal oxide-based nanoparticles: revealing their potential to enhance oil recovery in different wettability systems  

NASA Astrophysics Data System (ADS)

This paper presents systematic studies of hydrophilic metal oxide nanoparticles (NPs) dispersed in brine intended to reveal their potential to enhance oil recovery (EOR) in various rock wettability systems. The stability in suspension (nanofluid) of the NPs has been identified as a key factor related to their use as an EOR agent. Experimental techniques have been developed for nanofluid stability using three coupled methods: direct visual observation, surface conductivity and particle size measurements. The use of a dispersant has been investigated and has been shown to successfully improve metal oxide nanofluid stability as a function of its concentration. The dispersant alters the nanofluid properties, i.e. surface conductivity, pH and particle size distribution. A two-phase coreflood experiment was conducted by injecting the stable nanofluids as a tertiary process (nano-EOR) through core plugs with various wettabilities ranging from water-wet to oil-wet. The combination of metal oxide nanofluid and dispersant improved the oil recovery to a greater extent than either silica-based nanofluid or dispersant alone in all wettability systems. The contact angle, interfacial tension (IFT) and effluent were also measured. It was observed that metal oxide-based nanofluids altered the quartz plates to become more water-wet, and the results are consistent with those of the coreflood experiment. The particle adsorption during the transport process was identified from effluent analysis. The presence of NPs and dispersant reduced the IFT, but its reduction is sufficient to yield significant additional oil recovery. Hence, wettability alteration plays a dominant role in the oil displacement mechanism using nano-EOR.

Hendraningrat, Luky; Torsæter, Ole

2015-02-01

363

Two different spectrophotometric determinations of potential anticancer drug and its toxic metabolite.  

PubMed

Flutamide is a hormone therapy used for men with advanced prostate cancer. Flutamide is highly susceptible to hydrolysis with the production of 3-(trifluoromethyl)aniline, which is reported to be one of its toxic metabolites, impurities and related substances according to BP and USP. Flutamide was found to be stable when exposed to oxidation by 30% hydrogen peroxide and direct sunlight for up to 4h. Two accurate and sensitive spectrophotometric methods were used for determination of flutamide in bulk and in pharmaceutical formulations. Method (I) is the area under curve (AUC) spectrophotometric method that depends on measuring the AUC in the wavelength ranges of 275-305nm and 350-380nm and using Cramer's rule. The linearity range was found to be 1-35?g/mL and 0.5-16?g/mL for the drug and the degradate, respectively. In method (II), combination of the isoabsorptive and dual wavelength spectrophotometric methods was used for resolving the binary mixture. The absorbance at 249.2nm (?iso) was used for determination of total mixture concentration, while the difference in absorbance between 232nm and 341.2nm was used for measuring the drug concentration. By subtraction, the degradate concentration was obtained. Beer's law was obeyed in the range of 2-35?g/mL and 0.5-20?g/mL for the drug and its degradate, respectively. The two methods were validated according to USP guidelines and were applied for determination of the drug in its pharmaceutical dosage form. Moreover AUC method was used for the kinetic study of the hydrolytic degradation of flutamide. The kinetic degradation of flutamide was found to follow pseudo-first order kinetics and is pH and temperature dependent. Activation energy, kinetic rate constants and t1/2 at different temperatures and pH values were calculated. PMID:25795610

Farid, Nehal F; Abdelwahab, Nada S

2015-06-15

364

Morphology of platinum electrodeposits in the three-dimensional sublayer to full layer range produced under different potential modulations on highly oriented pyrolytic graphite.  

PubMed

The topography of platinum electrodes produced by electrodeposition (19 to 200 mC cm-2) on highly oriented pyrolytic graphite (HOPG) under different potential modulations was investigated by atomic force microscopy, scanning tunneling microscopy, and H-atom electrosorption voltammetry. To modulate electrodeposition, (i) triangular potential cycling at 0.1 V s-1, (ii) a linear cathodic potential at 0.1 V s-1 and anodic potential step cycling, and (iii) square wave potential cycling at 5000 Hz were utilized. AFM and STM imaging showed that at lower platinum loading the HOPG surface was partially covered by a 3D sublayer of platinum. Electrodes produced by procedure (i) were made of faceted platinum aggregates of about 200 nm and nanoclusters in the range of 5-20 nm; those that resulted from procedure (ii) consisted of anisotropic aggregates of nanoclusters arranged as quasi-parallel domains. These electrodes from (i) and (ii) behaved as fractal objects. The electrodes resulting from procedure (iii) exhibited a flat surface that behaved as a Euclidean object. For all WEs, as the platinum loading was increased the HOPG surface was fully covered by a thin 3D layer of platinum aggregates produced by electrodeposition and coalescence phenomena. Large platinum loading led to electrodes with fractal geometry. Statistical parameters (root-mean-square height, skewedness, kurtosis, anisotropy, Abbot curve, number of protrusions and valleys, and fractal dimension) were obtained from the analysis of AFM and STM imaging data. Platinum electrodeposition coupled to either H-adatom formation for procedures (i) and (ii) or phonon dispersion for (iii) was involved in the surface atom rearrangements related to electrofaceting. The H-adatom electrosorption voltammetry data were used to evaluate the real electrode surface area via the voltammetric charge and to advance a tentative explanation of the contribution of the different crystallographic facets to the global electrochemical process dominated by weak H-Pt adsorption interactions. PMID:17129018

Rodríguez Nieto, F J; Pasquale, M A; Cabrera, C R; Arvia, A J

2006-12-01

365

Toward adaptive management: the impacts of different management strategies on fish stocks and fisheries in a large regulated lake.  

PubMed

We applied the adaptive management approach to analyze the demand and feasibility of adaptive management of fish stocks in a large regulated lake, Oulujärvi, in northern Finland. The process consisted of four phases: (1) analysis of the current state of the fisheries system (fishers, related markets and industry, fisheries researches and authorities, related organizations, etc.); (2) analysis of the objectives of different stakeholders; (3) the composition of alternative management strategies and assessment of their impacts; and (4) recommendations for future management. We used catch statistics from the period 1973-1995 to analyze fish stocks and fishing. Fish species involved were brown trout (Salmo trutta L.), whitefish [Coregonus lavaretus (L.) sl.], vendace (Coregonus albula L.); and pikeperch (Stizostedion lucioperca L.). Questionnaires and interviews were applied to ascertain the opinions of different groups of fishermen. Several models and cost-benefit analysis were used to assess the ecological, economic, and social impacts of three alternative management strategies. The results emphasize that when determining stocking levels and fishing regulations, the system should be considered as a whole, and impacts on major fish species and different groups of fishermen should be assessed. The stocking policy and fishing regulations should also be flexible to accommodate changing biotic and societal conditions. The key questions in applying the adaptive management process in Oulujärvi fisheries are how to determine clear objectives for fisheries management, find a fisheries management structure that provides workable interactions between different stakeholders, and arrange cost-effective monitoring. The lessons learned from the Oulujärvi experience and recommendations for fisheries management are relevant to other lakes with conflicting objectives of different stakeholders. PMID:15517682

Marttunen, Mika; Vehanen, Teppo

2004-06-01

366

Difference  

NSDL National Science Digital Library

This interactive Flash applet models the difference meaning of subtraction. A child or teacher can compare two rows of beads and analyze the calculation they represent. Once a user sets up the two rows of beads (up to 30 each), the applet provides a series of animations which represents the rows with two number lines and then as a single number line with the difference indicated by a "jump". This applet works well with an interactive white board. A teacher's guide to this series of applets is cataloged separately.

2006-01-01

367

Structural Rationalization of a Large Difference in RNA Affinity Despite a Small Difference in Chemistry between Two 2'-O-Modified Nucleic Acid Analogs  

SciTech Connect

Chemical modification of nucleic acids at the 2'-position of ribose has generated antisense oligonucleotides (AONs) with a range of desirable properties. Electron-withdrawing substituents such as 2'-O-[2-(methoxy)ethyl] (MOE) confer enhanced RNA affinity relative to that of DNA by conformationally preorganizing an AON for pairing with the RNA target and by improving backbone hydration. 2'-Substitution of the ribose has also been shown to increase nuclease resistance and cellular uptake via changes in lipophilicity. Interestingly, incorporation of either 2'-O-[2-(methylamino)-2-oxoethyl]- (NMA) or 2'-O-(N-methylcarbamate)-modified (NMC) residues into AONs has divergent effects on RNA affinity. Incorporation of 2'-O-NMA-T considerably improves RNA affinity while incorporation of 2'-O-NMC-T drastically reduces RNA affinity. Crystal structures at high resolution of A-form DNA duplexes containing either 2'-O-NMA-T or 2'-O-NMC-T shed light on the structural origins of the surprisingly large difference in stability given the relatively minor difference in chemistry between NMA and NMC. NMA substituents adopt an extended conformation and use either their carbonyl oxygen or amino nitrogen to trap water molecules between phosphate group and sugar. The conformational properties of NMA and the observed hydration patterns are reminiscent of those found in the structures of 2'-O-MOE-modified RNA. Conversely, the carbonyl oxygen of NMC and O2 of T are in close contact, providing evidence that an unfavorable electrostatic interaction and the absence of a stable water structure are the main reasons for the loss in thermodynamic stability as a result of incorporation of 2'-O-NMC-modified residues.

Pattanayek, R.; Sethaphong, L.; Pan, C.; Prhavc, M.; Prakash, T.P.; Manoharan, M.; Egli, M. (Tennessee); (Isis Pharmaceuticals Inc.); (Alnylam Pharmaceuticals,); (Vanderbilt)

2010-03-08

368

Comparison diel signal of electrical potential differences in the trunk of trees with other eco-hydrological phenomena  

NASA Astrophysics Data System (ADS)

Diel fluctuation of hydrological features in forested lands is not a highly researched area. Many of the details of geophysical effects on the eco-hydrological phenomena in forest covered areas are poorly understood, too. In this paper some meteorological (net radiation, temperature, relative humidity data) and eco-hydrological (electrical potential differences data measured on the trunk of riparian trees, riparian groundwater level and stream base-flow data) parameters have been compared at a small time scale under forest covered environmental conditions. Analysed data set was measured at the outlet streamside point of the Hidegvíz Valley experimental catchment located at the eastern border of Alps. Meteorological data have been recorded by a micrometeorological station in the neighbourhood of streamflow, groundwater level reading and electrical potential differences measuring sensors. Groundwater level and streamflow discharges were calculated from data of water pressure principle functioning sensor. Electrical potential differences (EPD) have been recorded for several years between electrodes inserted in sixteen selected sites of trunks of two Alder trees (Alnus Glutinosa L.). The measured EPDs are related to the xylem-sapflow density. All of the examined eco-hydrological phenomenon are induced by the evapotranspiration. Therefore Penman-Monteith evapotranspiration rate were calculated on the basis of meteorological data for comparison of EPD, groundwater and streamflow signal. Detailed stochastic analysis (like dynamic spectrum, cross-correlation analysis etc.) was employed on the detrended eco-hydrological data series. These initial results help us better understanding of atmosphere, vegetation, water relationship in case of a streamside zone in hilly region. Keywords: diel fluctuation, electrical potential differences, sap flow, evapotranspiration

Koppan, A.; Kalicz, P.; Gribovszki, Z.; Vig, P.

2009-04-01

369

Nonlinear free vibration analysis of simply supported piezo-laminated plates with random actuation electric potential difference and material properties  

Microsoft Academic Search

Studies are made on nonlinear free vibrations of simply supported piezo-laminated rectangular plates with immovable edges utilizing Kirchoff’s hypothesis and von Kármán strain–displacement relations. The effect of random material properties of the base structure and actuation electric potential difference on the nonlinear free vibration of the plate is examined. The study is confined to linear-induced strain in the piezoelectric layer

K. Jayakumar; D. Yadav; B. Nageswara Rao

2009-01-01

370

Different effects of two gold compounds on muscle contraction, membrane potential and ryanodine receptor.  

PubMed

Effects of gold sodium thiomalate and NaAuCl4 on skeletal muscle function were studied using intact single fibres of frog skeletal muscle and fragmented sarcoplasmic reticulum prepared from frog and rabbit skeletal muscles. Gold sodium thiomalate at a concentration of 500 microM decreased tension amplitude by 27% and resting membrane potential by 5.3% after 30 and 22 min, respectively. The duration of tetanus tension was markedly shortened by 500 microM gold sodium thiomalate. When 10 microM NaAuCl4 was applied to gold sodium thiomalate-pretreated fibres, the fibres lost the ability to contract upon electrical stimulation, similar to the effects of 10 microM NaAuCl4 alone. In the presence of thiomalic acid, on the other hand, NaAuCl4 did not completely block tetanus tension even at 50 microM. Thiomalic acid also inhibited NaAuCl4-induced membrane depolarization. These findings suggest that thiomalate masks the effects of gold ion on muscle function. When sarcoplasmic reticulum vesicles were incorporated into lipid bilayers, exposure of the cis side of the Ca2+-release channel to 100 microM gold sodium thiomalate rapidly increased the open probability of the channel 3.3-fold, from 0.032 in controls to 0.105, with an increase in number of open events and a decrease in mean closed time. The ability of NaAuCl4 to activate the Ca2+-release channel was much stronger than that of gold sodium thiomalate. Only 1 microM NaAuCl4 was enough to activate the channel and this gold was effective from either side of the channel. These results suggest that gold sodium thiomalate could be used as an antirheumatic drug without considering severe side-effects on skeletal muscle. Coexistent thiomalate probably contributes to protection of muscle function from side-effects of gold ion. PMID:10422793

Oba, T; Ishikawa, T; Yamaguchi, M

1999-06-25

371

Post-traumatic stress disorder and migraine: epidemiology, sex differences, and potential mechanisms.  

PubMed

Migraine is a common, often disabling disorder associated with a significant personal and societal burden. The presence of post-traumatic stress disorder (PTSD) may increase this disability substantially. Migraine and PTSD are both up to 3 times more common in women than in men. The divergence in prevalence rates of migraine and PTSD that occurs between the sexes after puberty suggests that gonadal hormones play an important role. In addition, the preponderance of PTSD in women may be related to their higher rates of interpersonal trauma, the most common cause of PTSD. However, recent data suggest that although the odds of PTSD are increased in both women and men with episodic migraine, this association is stronger in men than women. In this paper, we examine the epidemiology of PTSD and migraine, with an emphasis on the known sex differences. We then discuss the neurobiological changes associated with PTSD, the current hypotheses for the mechanisms relating PTSD and migraine, and the treatment implications of these findings. PMID:21592096

Peterlin, B Lee; Nijjar, Satnam S; Tietjen, Gretchen E

2011-06-01

372

Occurrence and potential health risk of Cryptosporidium and Giardia in different water catchments in Belgium.  

PubMed

Human wastewater and livestock can contribute to contamination of surface water with Cryptosporidium and Giardia. In countries where a substantial proportion of drinking water is produced from surface water, e.g., Belgium, this poses a constant threat on drinking water safety. Our objective was to monitor the presence of Cryptosporidium and Giardia in different water catchment sites in Belgium and to discriminate between (oo)cysts from human or animal origin using genotyping. Monthly samples were collected from raw water and purified drinking water at four catchment sites. Cryptosporidium and Giardia were detected using USEPA method 1623 and positive samples were genotyped. No contamination was found in purified water at any site. In three catchments, only low numbers of (oo)cysts were recovered from raw water samples (<1/liter), but raw water samples from one catchment site were frequently contaminated with Giardia (92 %) and Cryptosporidium (96 %), especially in winter and spring. Genotyping of Giardia in 38 water samples identified the presence of Giardia duodenalis assemblage AI, AII, BIV, BIV-like, and E. Cryptosporidium andersoni, Cryptosporidium suis, Cryptosporidium horse genotype, Cryptosporidium parvum, and Cryptosporidium hominis were detected. The genotyping results suggest that agriculture may be a more important source of surface water contamination than human waste in this catchment. In catchment sites with contaminated surface water, such as the Blankaart, continuous monitoring of treated water for the presence of Cryptosporidium and Giardia would be justified and (point) sources of surface water contamination should be identified. PMID:25616782

Ehsan, Amimul; Geurden, Thomas; Casaert, Stijn; Paulussen, Jef; De Coster, Lut; Schoemaker, Toon; Chalmers, Rachel; Grit, Grietje; Vercruysse, Jozef; Claerebout, Edwin

2015-02-01

373

Screening of Different Extracts from Artemisia Species for Their Potential Antimalarial Activity  

PubMed Central

The formation of hemozoin (malaria pigment) has been proposed as an ideal drug target for antimalarial screening programs. In this study, we used an improved, cost-effective and high-throughput spectrophotometric assay to screen plant extracts for finding novel antimalarial plant sources. Fifteen extracts with different polarity from three Iranian Artemisia species, A. ciniformis, A. biennis and A. turanica, were assessed for their antimalarial activity by in-vitro ?-hematin formation assay. The most potent effect was observed in dichloromethane (DCM) extract of A. ciniformis with IC50 and IC90 values of 0.92 ± 0.01 and 1.29 ± 0.02 mg/mL, respectively. Ethyl acetate (EtOAC) extracts of A. biennis and A. turanica also showed significant antimalarial activities with IC50 values of 1.11 ± 0.02 and 1.35 ± 0.08 mg/mL and IC90 values of 1.22 ± 0.04 and 2.81 ± 0.21 mg/mL, respectively. Based on these results, it is possible to conclude that the components with strong antimalarial activity have been concentrated in the medium-polar extracts.

Mojarrab, Mahdi; Naderi, Rozhin; Heshmati Afshar, Fariba

2015-01-01

374

Two different models to predict ionic-liquid diffraction patterns: fixed-charge versus polarizable potentials.  

PubMed

This study reports the performance of classical molecular dynamics (MD) in predicting the X-ray diffraction patterns of butylammonium nitrate (BAN) and two derivatives, 4-hydroxybutan-1-ammonium nitrate (4-HOBAN) and 4-methoxybutan-1-ammonium nitrate (4-MeOBAN). The structure functions and radial distribution functions obtained from energy-dispersive X-ray diffraction spectra, recorded newly for BAN and for the first time for 4-MeOBAN and 4-HOBAN, are compared with the corresponding quantities calculated from MD trajectories, to access information on the morphology of these liquids. The different behavior of two force fields, a polarizable multipole force field and a fixed-charge one supplemented by an explicit three-body term, is shown. The three-body force field proves to be superior in reproducing the intermediate q range, for which the polarizable force field gives the wrong peak position and intensities. In addition, both models can correctly account for the presence or absence of a low q peak in the scattering patterns. PMID:25359089

Campetella, Marco; Gontrani, Lorenzo; Leonelli, Francesca; Bencivenni, Luigi; Caminiti, Ruggero

2015-01-12

375

Effect of pulsed electric field treatment on hot-boned muscles of different potential tenderness.  

PubMed

In this study, the effect of pulsed electric field (PEF) treatment and ageing on the quality of beef M. longissimus lumborum (LL) and M. semimembranosus (SM) muscles was evaluated, including the tenderness, water loss and post-mortem proteolysis. Muscles were obtained from 12 steers (6 steers for each muscle), removed from the carcasses 4hour postmortem and were treated with pulsed electric field within 2h. Six different pulsed electric field intensities (voltages of 5 and 10kV×frequencies of 20, 50 and 90Hz) plus a control were applied to each muscle to determine the optimum treatment conditions. Beef LL was found to get tougher with increasing treatment frequency whereas beef SM muscle was found to have up to 21.6% reduction in the shear force with pulsed electric field treatment. Post-mortem proteolysis showed an increase in both troponin and desmin degradation in beef LL treated with low intensity PEF treatment (20Hz) compared to non-treated control samples. PMID:25754097

Suwandy, Via; Carne, Alan; van de Ven, Remy; Bekhit, Alaa El-Din A; Hopkins, David L

2015-07-01

376

Near infrared photoresponse study of large area multi-walled carbon nanotube film with different electrode spacing  

NASA Astrophysics Data System (ADS)

Photoconductivity of carbon nanotube have generated considerable debate in terms of whether the photoresponse is (i) due to photon induced charge carrier (excitonic), (ii) due to heating of the CNT network (bolometric), or (iii) caused by photodesorption of oxygen molecules at the surface of the CNT. In addition, the role of the metal electrode -- CNT contact's effect on the photoresponse has also been debated. In this talk, we will present near -infrared photoresponse study of multi-walled carbon nanotube (MWCNT) film with different electrode spacings. We found that there is a large enhancement of photocurrent upon laser illumination and the photocurrent strongly depends on the position of the laser spot with maximum response occurring at the metal -- film interface. We also show that the photoresponse is rather slow (˜1s) and increases with increasing electrode spacing. We will discuss the origin of the position dependent photocurrent and slow time response.

Sarker, Biddut; Arif, M.; Stokes, Paul; Kabir, Alamgir; Khondaker, Saiful I.

2009-03-01

377

Exploiting large non-isomorphous differences for phase determination of a G-segment invertase–DNA complex  

PubMed Central

Crystals of the G-segment invertase in complex with a 37-base-pair asymmetric DNA duplex substrate had an unusually high solvent content of 88% and diffracted to a maximal resolution of about 5.0?Å. These crystals exhibited a high degree of non-isomorphism and anisotropy, which presented a serious challenge for structure determination by isomorphous replacement. Here, a procedure of cross-crystal averaging is described that uses large non-isomorphous crystallographic data with a priori information of an approximate molecular boundary as determined from a minimal amount of experimental phase information. Using this procedure, high-quality experimental phases were obtained that have enabled it to be shown that the conformation of the bound substrate DNA duplex significantly differs from those of substrates bound in other serine recombinase–DNA complexes. PMID:24598738

Ritacco, Christopher J.; Steitz, Thomas A.; Wang, Jimin

2014-01-01

378

A novel DAX-1 mutation presented with precocious puberty and hypogonadotropic hypogonadism in different members of a large pedigree.  

PubMed

Patients with DAX-1 gene mutations on chromosome Xp21 usually present with adrenal hypoplasia congenita and hypogonadotropic hypogonadism. Yet, neither correlation between the type of mutation and the age of onset of the disease nor mechanism of the mutation on puberty is fully understood. Here, we report a novel non-sense p.Gln208X mutation in the amino terminal domain of the DAX-1 gene observed in a large family with three boys presenting with adrenal manifestations at different ages. Furthermore, two boys developed spontaneous puberty that failed to progress at similar ages, whereas the other boy developed precocious puberty at 10 month of age. The unique structure of the DAX-1 gene may explain this phenotypic variability. However, more studies are needed to understand the role of the DAX-1 gene on development of the adrenal gland and hypothalamus-pituitary-gonadal axis. PMID:23585174

Durmaz, Erdem; Turkkahraman, Doga; Berdeli, Afig; Atan, Merve; Karaguzel, Gulay; Akcurin, Sema; Bircan, Iffet

2013-01-01

379

Effects of different culture conditions on biological potential and metabolites production in three Penicillium isolates.  

PubMed

The genus Penicillium is well known for its importance in drug and food production. Certain species are produced on an industrial scale for the production of antibiotics (e.g. penicillin) or for insertion in food (e.g. cheese). In the present work, three Penicillium species, part of the natural mycobiota growing on various food products were selected - P. ochrochloron, P. funiculosum and P. verrucosum var. cyclopium. The objective of our study was to value these species from the point of view of production of bioactive metabolites. The species were obtained after inoculation and growth in Czapek and Malt media. Both mycelia and culture media were analyzed to monitor the production of different metabolites by each fungus and their release to the culture medium. The concentrations of sugars, organic acids, phenolic acids and tocopherols were determined. Antioxidant activity of the phenolic extracts was evaluated, as also the antimicrobial activity of phenolic acids, organic acids and tocopherols extracts. Rhamnose, xylose, fructose and trehalose were found in all the mycelia and culture media; the prevailing organic acids were oxalic and fumaric acids, and protocatechuic and p-hydroxybenzoic acids were the most common phenolic acids; ?-tocopherol was the most abundant vitamin E isoform. Generally, the phenolic extracts corresponding to the mycelia samples revealed higher antioxidant activity. Concerning the antimicrobial activity there were some fluctuations, however all the studied species revealed activity against the tested strains. Therefore, the in-vitro bioprocesses can be an alternative for the production of bioactive metabolites that can be used by pharmaceutical industry. PMID:24261405

Reis, Filipa S; ?iri?, Ana; Stojkovi?, Dejan; Barros, Lillian; Ljaljevi?-Grbi?, Milica; Sokovi?, Marina; Ferreira, Isabel C F R

2015-02-01

380

Gender differences in methionine accumulation and metabolism in freshly isolated mouse hepatocytes: Potential roles in toxicity  

SciTech Connect

L-Methionine (Met) is hepatotoxic at high concentrations. Because Met toxicity in freshly isolated mouse hepatocytes is gender-dependent, the goal of this study was to assess the roles of Met accumulation and metabolism in the increased sensitivity of male hepatocytes to Met toxicity compared with female hepatocytes. Male hepatocytes incubated with Met (30 mM) at 37 {sup o}C exhibited higher levels of intracellular Met at 0.5, 1.0, and 1.5 h, respectively, compared to female hepatocytes. Conversely, female hepatocytes had higher levels of S-adenosyl-L-methionine compared to male hepatocytes. Female hepatocytes also exhibited higher L-methionine-L-sulfoxide levels relative to control hepatocytes, whereas the increases in L-methionine-D-sulfoxide (Met-D-O) levels were similar in hepatocytes of both genders. Addition of aminooxyacetic acid (AOAA), an inhibitor of Met transamination, significantly increased Met levels at 1.5 h and increased Met-D-O levels at 1.0 and 1.5 h only in Met-exposed male hepatocytes. No gender differences in cytosolic Met transamination activity by glutamine transaminase K were detected. However, female mouse liver cytosol exhibited higher methionine-DL-sulfoxide (MetO) reductase activity than male mouse liver cytosol at low (0.25 and 0.5 mM) MetO concentrations. Collectively, these results suggest that increased cellular Met accumulation, decreased Met transmethylation, and increased Met and MetO transamination in male mouse hepatocytes may be contributing to the higher sensitivity of the male mouse hepatocytes to Met toxicity in comparison with female mouse hepatocytes.

Dever, Joseph T. [Department of Comparative Biosciences and Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin (United States); Elfarra, Adnan A. [Department of Comparative Biosciences and Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin (United States)], E-mail: aelfarra@wisc.edu

2009-05-01

381

The potential of different bio adsorbents for removing phenol from its aqueous solution.  

PubMed

The use of natural resources for the removal of phenol and phenolic compounds is being looked upon by researchers in preference to other prevailing methods. In the present study, different biosorbents, brown algae (Padina pavonia), fresh water macrophyta (Ceratophyllum demersum), and black tea residue, were tested as adsorbent for the removal of phenol from aqueous solutions. The optimum conditions for maximum adsorption in terms of concentration of the adsorbate and pH were identified. The results show that the initial concentration increases as the removal of phenol increases in C. demersum; in the case of the other two adsorbents, the initial concentration increases as the removal of phenol decreases, especially for an initial concentration lower than 100 and 1,000 ?g/L for P. pavonia and black tea residue, respectively. Maximum percentage removal of phenol by each adsorbent is 77, 50.8, and 29 % for C. demersum, P. pavonia, and black tea residue, respectively. Also, the biosorption capacity was strongly influenced by the pH of the aqueous solution with an observed maximum phenol removal at pH of around 6-10. The first biosorbent (black tea residue) displays the maximum adsorption capacity at a pH of 10 with a percentage sorption capacity of 84 %; P. pavonia revealed a greater adsorption percentage at pH?10, reaching 30 %, while for C. demersum, the removal of phenol increases with the increase in initial pH up to 6.0 and decreases drastically with further increase in initial pH. The Freundlich, Langmuir, and Brauner-Emmet-Teller adsorption models were applied to describe the equilibrium isotherms. The results reveal that the equilibrium data for all phenol adsorbents fitted the Freundlich model which seemed to be the best-fitting model for the experimental results with similar values of coefficient of determination. PMID:23242505

Abdallah, Maha Ahmed Mohamed

2013-08-01

382

Recruitment potential of two perennial grasses with different growth forms at a semiarid-arid transition zone.  

PubMed

The objective of this study was to quantify differences in recruitment potential (seed production, seed presence in the soil) for two congeneric perennial grasses (Bouteloua gracilis, Bouteloua eriopoda [Poaceae]) that dominate adjacent arid and semiarid grassland biomes. It was hypothesized that these species have different recruitment strategies at the biome transition zone that are related to differences in their growth form and longevity. Recruitment potential for each Bouteloua species was compared in patches dominated by one or both species or codominated by the invasive shrub, Larrea tridentata (Zygophyllaceae). Regional variation in recruitment was examined for B. gracilis for cases in which comparable data were available in the literature for a site located within the semiarid grassland biome. The short-lived stoloniferous species B. eriopoda produced more seeds per plant than the long-lived bunchgrass B. gracilis, yet seed viability (<60%) and presence in the soil were lower. Mean viability of B. gracilis was higher (>90%) than that of B. eriopoda, and a greater percentage of seeds produced on a square meter basis was found in the soil (10-25%). Similar patterns were found for both species in all grass-dominated patches. Bouteloua eriopoda plants growing in patches codominated by L. tridentata produced fewer seeds per plant with lower viability, and fewer seeds were found in the soil compared to grass-dominated patches. Regional comparisons found greater seed production per square meter and more seeds in the soil for B. gracilis at the transitional site compared with a cooler, wetter site located within the semiarid grassland biome. These differences in recruitment potential along with published differences in rates of seedling establishment and vegetative spread may explain, at least in part, localized patterns in species dominance. PMID:21665589

Peters, Debra P C

2002-10-01

383

Neurite, a Finite Difference Large Scale Parallel Program for the Simulation of Electrical Signal Propagation in Neurites under Mechanical Loading  

PubMed Central

With the growing body of research on traumatic brain injury and spinal cord injury, computational neuroscience has recently focused its modeling efforts on neuronal functional deficits following mechanical loading. However, in most of these efforts, cell damage is generally only characterized by purely mechanistic criteria, functions of quantities such as stress, strain or their corresponding rates. The modeling of functional deficits in neurites as a consequence of macroscopic mechanical insults has been rarely explored. In particular, a quantitative mechanically based model of electrophysiological impairment in neuronal cells, Neurite, has only very recently been proposed. In this paper, we present the implementation details of this model: a finite difference parallel program for simulating electrical signal propagation along neurites under mechanical loading. Following the application of a macroscopic strain at a given strain rate produced by a mechanical insult, Neurite is able to simulate the resulting neuronal electrical signal propagation, and thus the corresponding functional deficits. The simulation of the coupled mechanical and electrophysiological behaviors requires computational expensive calculations that increase in complexity as the network of the simulated cells grows. The solvers implemented in Neurite—explicit and implicit—were therefore parallelized using graphics processing units in order to reduce the burden of the simulation costs of large scale scenarios. Cable Theory and Hodgkin-Huxley models were implemented to account for the electrophysiological passive and active regions of a neurite, respectively, whereas a coupled mechanical model accounting for the neurite mechanical behavior within its surrounding medium was adopted as a link between electrophysiology and mechanics. This paper provides the details of the parallel implementation of Neurite, along with three different application examples: a long myelinated axon, a segmented dendritic tree, and a damaged axon. The capabilities of the program to deal with large scale scenarios, segmented neuronal structures, and functional deficits under mechanical loading are specifically highlighted. PMID:25680098

García-Grajales, Julián A.; Rucabado, Gabriel; García-Dopico, Antonio; Peña, José-María; Jérusalem, Antoine

2015-01-01

384

Neurite, a Finite Difference Large Scale Parallel Program for the Simulation of Electrical Signal Propagation in Neurites under Mechanical Loading.  

PubMed

With the growing body of research on traumatic brain injury and spinal cord injury, computational neuroscience has recently focused its modeling efforts on neuronal functional deficits following mechanical loading. However, in most of these efforts, cell damage is generally only characterized by purely mechanistic criteria, functions of quantities such as stress, strain or their corresponding rates. The modeling of functional deficits in neurites as a consequence of macroscopic mechanical insults has been rarely explored. In particular, a quantitative mechanically based model of electrophysiological impairment in neuronal cells, Neurite, has only very recently been proposed. In this paper, we present the implementation details of this model: a finite difference parallel program for simulating electrical signal propagation along neurites under mechanical loading. Following the application of a macroscopic strain at a given strain rate produced by a mechanical insult, Neurite is able to simulate the resulting neuronal electrical signal propagation, and thus the corresponding functional deficits. The simulation of the coupled mechanical and electrophysiological behaviors requires computational expensive calculations that increase in complexity as the network of the simulated cells grows. The solvers implemented in Neurite-explicit and implicit-were therefore parallelized using graphics processing units in order to reduce the burden of the simulation costs of large scale scenarios. Cable Theory and Hodgkin-Huxley models were implemented to account for the electrophysiological passive and active regions of a neurite, respectively, whereas a coupled mechanical model accounting for the neurite mechanical behavior within its surrounding medium was adopted as a link between electrophysiology and mechanics. This paper provides the details of the parallel implementation of Neurite, along with three different application examples: a long myelinated axon, a segmented dendritic tree, and a damaged axon. The capabilities of the program to deal with large scale scenarios, segmented neuronal structures, and functional deficits under mechanical loading are specifically highlighted. PMID:25680098

García-Grajales, Julián A; Rucabado, Gabriel; García-Dopico, Antonio; Peña, José-María; Jérusalem, Antoine

2015-01-01

385

The molecular signature of mediastinal large B-cell lymphoma differs from that of other diffuse large B-cell lymphomas and shares features with classical Hodgkin lymphoma  

Microsoft Academic Search

Mediastinal large B-cell lymphoma (MLBCL) is a recently identified subtype of diffuse large B-cell lymphoma (DLBCL) that char- acteristically presents as localized tu- mors in young female patients. Although MLBCL has distinctive pathologic fea- tures, it clinically resembles the nodular sclerosis subtype of classical Hodgkin lymphoma (cHL). To elucidate the molecu- lar features of MLBCL, we compared the gene expression

Kerry J. Savage; Stefano Monti; Jeffery L. Kutok; Giorgio Cattoretti; Donna Neuberg; Laurence de Leval; Paul Kurtin; Paola Dal Cin; Christine Ladd; Friedrich Feuerhake; Ricardo C. T. Aguiar; Sigui Li; Gilles Salles; Francoise Berger; Wen Jing; Geraldine S. Pinkus; Thomas Habermann; Riccardo Dalla-Favera; Lee Harris; Jon C. Aster; Todd R. Golub; Margaret A. Shipp

2003-01-01

386

Experimental and theoretical study of the electrical conductivity, NMR properties under different salinities and the membrane potential of shaly sandstone  

NASA Astrophysics Data System (ADS)

Although the salinity of formation water determines a list of important petrophysical parameters in reservoir rocks, little work on the salinity effects on the bound water saturation and the consequent effects on the electrical and nuclear magnetic resonance (NMR) characteristics has been done. In this study, the measurements of the bound water saturation, electrical conductivity and NMR responses of rocks with different salinities have been conducted. The experimental results indicate that the bound water saturation of shaly sandstone decreases with an increase in the salinity. The electrical conductivity of rock with low salinity formation water may be high because of high bound water saturation and, additionally, clay content. The transverse relaxation time (T2) spectrum distribution changes with the salinity of solution. The cutoff value of the T2 decreases with the increase of the solution salinity. The property of membrane potential in shaly sands is critical in determining the resistivity of formation water (Rw) using a spontaneous potential (SP) log. In order to understand the influences of cation exchange capacity, hydrocarbon saturation and salinity on membrane potential, a systematical study on the membrane potential of oil-bearing shaly sands has been conducted based on electrochemical theory and the electrical conductivity properties of shaly sands. Laboratory experiments were designed and carried out. The experimental results show that the membrane potential of shaly sands increases with the increase of cation exchange capacity, the hydrocarbon saturation and the salinity difference of the solutions. The developed membrane theory in shaly sands should improve SP log interpretation. If using SP to predict Rw, we suggest that the influences of hydrocarbon saturation and shale content should be taken into account.

Deng, Shaogui; Wang, Xiaochang; Li, Guoxin; Fan, Yiren

2006-12-01

387

A large survey of Croatian wild mammals for Giardia duodenalis reveals a low prevalence and limited zoonotic potential.  

PubMed

Wild mammals are considered an important source of potentially zoonotic Giardia duodenalis parasites, yet surprisingly little information is available on the actual prevalence and the genetic identity of the species they harbor. A large survey was conducted in Croatia by collecting 832 fecal samples from red deer (Cervus elaphus, n = 374), roe deer (Capreolus capreolus, n = 21), wild boars (Sus scrofa, n = 144), foxes (Vulpes vulpes, n = 66), bears (Ursus arctos, n = 19), wolves (Canis lupus, n = 127), jackals (Canis aureus, n = 8), and hares (Lepus europeus, n = 73). Fecal samples were tested for the presence of Giardia cysts using fluorescent microscopy. The observed prevalence ranged from low (1% in red deer, 1.7% in wild boars, and 4.5% in foxes) to moderate (10% in wolves and 12.5% in jackals) to high (24% in roe deer). No cysts were observed in bears and hares. Polymerase chain reaction was performed on microscopically positive samples to amplify fragments of the small subunit ribosomal gene, the ribosomal 5.8S gene and the two flanking internal transcribed sequences, and the triose phosphate isomerase gene. Sequence analysis showed a predominance of G. duodenalis assemblage A in both ruminants (genotypes A1 and A3) and carnivores (genotype A1). G. duodenalis assemblages B, C, and D, as well as Giardia microti, were also detected in this study. This is the first molecular description of the parasite from the red deer, the wolf, and the jackal. The data point to a minor role of wild mammals as reservoirs of zoonotic assemblages of G. duodenalis, albeit cycling between sylvatic and domestic animals is possible. PMID:21142957

Beck, Relja; Sprong, Hein; Lucinger, Snjezana; Pozio, Edoardo; Cacciò, Simone M

2011-08-01

388

A large population of king crabs in Palmer Deep on the west Antarctic Peninsula shelf and potential invasive impacts  

PubMed Central

Lithodid crabs (and other skeleton-crushing predators) may have been excluded from cold Antarctic continental shelf waters for more than 14 Myr. The west Antarctic Peninsula shelf is warming rapidly and has been hypothesized to be soon invaded by lithodids. A remotely operated vehicle survey in Palmer Deep, a basin 120 km onto the Antarctic shelf, revealed a large, reproductive population of lithodids, providing the first evidence that king crabs have crossed the Antarctic shelf. DNA sequencing and morphology indicate the lithodid is Neolithodes yaldwyni Ahyong & Dawson, previously reported only from Ross Sea waters. We estimate a N. yaldwyni population density of 10 600 km?2 and a population size of 1.55 × 106 in Palmer Deep, a density similar to lithodid populations of commercial interest around Alaska and South Georgia. The lithodid occurred at depths of more than 850 m and temperatures of more than 1.4°C in Palmer Deep, and was not found in extensive surveys of the colder shelf at depths of 430–725 m. Where N. yaldwyni occurred, crab traces were abundant, megafaunal diversity reduced and echinoderms absent, suggesting that the crabs have major ecological impacts. Antarctic Peninsula shelf waters are warming at approximately 0.01°C yr?1; if N. yaldwyni is currently limited by cold temperatures, it could spread up onto the shelf (400–600 m depths) within 1–2 decades. The Palmer Deep N. yaldwyni population provides an important model for the potential invasive impacts of crushing predators on vulnerable Antarctic shelf ecosystems. PMID:21900324

Smith, Craig R.; Grange, Laura J.; Honig, David L.; Naudts, Lieven; Huber, Bruce; Guidi, Lionel; Domack, Eugene

2012-01-01

389

Estimating the Potential Impacts of Large Mesopredators on Benthic Resources: Integrative Assessment of Spotted Eagle Ray Foraging Ecology in Bermuda  

PubMed Central

Declines of large sharks and subsequent release of elasmobranch mesopredators (smaller sharks and rays) may pose problems for marine fisheries management as some mesopredators consume exploitable shellfish species. The spotted eagle ray (Aetobatus narinari) is the most abundant inshore elasmobranch in subtropical Bermuda, but its predatory role remains unexamined despite suspected abundance increases and its hypothesized specialization for mollusks. We utilized a combination of acoustic telemetry, benthic invertebrate sampling, gut content analysis and manipulative experiments to assess the impact of spotted eagle rays on Bermudian shellfish resources. Residency and distribution of adult spotted eagle rays was monitored over two consecutive summers in Harrington Sound (HS), an enclosed inshore lagoon that has historically supported multiple recreational and commercial shellfish species. Telemetered rays exhibited variable fidelity (depending on sex) to HS, though generally selected regions that supported relatively high densities of potential mollusk prey. Gut content analysis from rays collected in HS revealed a diet of mainly bivalves and a few gastropods, with calico clam (Macrocallista maculata) representing the most important prey item. Manipulative field and mesocosm experiments with calico clams suggested that rays selected prey patches based on density, though there was no evidence of rays depleting clam patches to extirpation. Overall, spotted eagle rays had modest impacts on local shellfish populations at current population levels, suggesting a reduced role in transmitting cascading effects from apex predator loss. However, due to the strong degree of coupling between rays and multiple protected mollusks in HS, ecosystem-based management that accounts for ray predation should be adopted. PMID:22802956

Ajemian, Matthew J.; Powers, Sean P.; Murdoch, Thaddeus J. T.

2012-01-01

390

Germination responses to temperature and water potential in Jatropha curcas seeds: a hydrotime model explains the difference between dormancy expression and dormancy induction at different incubation temperatures  

PubMed Central

Background and Aims Jatropha curcas is a drought-resistant tree whose seeds are a good source of oil that can be used for producing biodiesel. A successful crop establishment depends on a rapid and uniform germination of the seed. In this work we aimed to characterize the responses of J. curcas seeds to temperature and water availability, using thermal time and hydrotime analysis, Methods Thermal and hydrotime analysis was performed on germination data obtained from the incubation of seeds at different temperatures and at different water potentials. Key Results Base and optimum temperatures were 14·4 and 30 °C, respectively. Approximately 20 % of the seed population displayed absolute dormancy and part of it displayed relative dormancy which was progressively expressed in further fractions when incubation temperatures departed from 25 °C. The thermal time model, but not the hydrotime model, failed to describe adequately final germination percentages at temperatures other than 25 °C. The hydrotime constant, ?H, was reduced when the incubation temperature was increased up to 30 °C, the base water potential for 50 % germination,?b(50), was less negative at 20 and 30 °C than at 25 °C, indicating either expression or induction of dormancy. At 20 °C this less negative ?b(50) explained satisfactorily the germination curves obtained at all water potentials, while at 30 °C it had to be corrected towards even less negative values to match observed curves at water potentials below 0. Hence, ?b(50) appeared to have been further displaced to less negative values as exposure to 30 °C was prolonged by osmoticum. These results suggest expression of dormancy at 20 °C and induction of secondary dormancy above 25 °C. This was confirmed by an experiment showing that inhibition of germination imposed by temperatures higher than 30 °C, but not that imposed at 20 °C, is a permanent effect. Conclusions This study revealed (a) the extremely narrow thermal range within which dormancy problems (either through expression or induction of dormancy) may not be encountered; and (b) the high sensitivity displayed by these seeds to water shortage. In addition, this work is the first one in which temperature effects on dormancy expression could be discriminated from those on dormancy induction using a hydrotime analysis. PMID:21917817

Windauer, Liliana B.; Martinez, J.; Rapoport, D.; Wassner, D.; Benech-Arnold, Roberto

2012-01-01

391

Traumatic brain injury and hemorrhagic shock: evaluation of different resuscitation strategies in a large animal model of combined insults.  

PubMed

Traumatic brain injury (TBI) and hemorrhagic shock (HS) are the leading causes of trauma-related mortality and morbidity. Combination of TBI and HS (TBI + HS) is highly lethal, and the optimal resuscitation strategy for this combined insult remains unclear. A critical limitation is the lack of suitable large animal models to test different treatment strategies. We have developed a clinically relevant large animal model of TBI + HS, which was used to evaluate the impact of different treatments on brain lesion size and associated edema. Yorkshire swine (42-50 kg) were instrumented to measure hemodynamic parameters and intracranial pressure. A computer-controlled cortical impact device was used to create a TBI through a 20-mm craniotomy: 15-mm cylindrical tip impactor at 4 m/s velocity, 100-ms dwell time, and 12-mm penetration depth. Volume-controlled hemorrhage was started (40% blood volume) concurrent with the TBI. After 2 h of shock, animals were randomized to one of three resuscitation groups (n = 5/group): (a) normal saline (NS); (b) 6% hetastarch, Hextend (Hex); and (c) fresh frozen plasma (FFP). Volumes of Hex and FFP matched the shed blood, whereas NS was three times the volume. After 6 h of postresuscitation monitoring, brains were sectioned into 5-mm slices and stained with TTC (2,3,5-triphenyltetrazolium chloride) to quantify the lesion size and brain swelling. Combination of 40% blood loss with cortical impact and a period of shock (2 h) resulted in a highly reproducible brain injury. Total fluid requirements were lower in the Hex and FFP groups. Lesion size and brain swelling in the FFP group (2,160 ± 202.63 mm and 22% ± 1.0%, respectively) were significantly smaller than those in the NS group (3,285 ± 130.8 mm3 and 37% ± 1.6%, respectively) (P < 0.05). Hex treatment decreased the swelling (29% ± 1.6%) without reducing the lesion size. Early administration of FFP reduces the size of brain lesion and associated swelling in a large animal model of TBI + HS. In contrast, artificial colloid (Hex) decreases swelling without reducing the actual size of the brain lesion. PMID:22575994

Jin, Guang; DeMoya, Marc A; Duggan, Michael; Knightly, Thomas; Mejaddam, Ali Y; Hwabejire, John; Lu, Jennifer; Smith, William Michael; Kasotakis, Georgios; Velmahos, George C; Socrate, Simona; Alam, Hasan B

2012-07-01

392

A large Bradbury Nielsen ion gate with flexible wire spacing based on photo-etched stainless steel grids and its characterization applying symmetric and asymmetric potentials  

E-print Network

Bradbury Nielsen gates are well known devices used to switch ion beams and are typically applied in mass or mobility spectrometers for separating beam constituents by their different flight or drift times. A Bradbury Nielsen gate consists of two interleaved sets of electrodes. If two voltages of the same amplitude but opposite polarity are applied the gate is closed, and for identical (zero) potential the gate is open. Whereas former realizations of the device employ actual wires resulting in difficulties with winding, fixing and tensioning them, our approach is to use two grids photo-etched from a metallic foil. This design allows for simplified construction of gates covering large beam sizes up to at least 900\\,mm$^2$ with variable wire spacing down to 250\\,\\textmu m. By changing the grids the wire spacing can be varied easily. A gate of this design was installed and systematically tested at TRIUMF's ion trap facility, TITAN, for use with radioactive beams to separate ions with different mass-to-charge ratios by their time-of-flight.

T. Brunner; A. R. Mueller; K. O'Sullivan; M. C. Simon; M. Kossick; S. Ettenauer; A. T. Gallant; E. Mané; D. Bishop; M. Good; G. Gratta; J. Dilling

2011-09-14

393

Modeling of region-specific fMRI BOLD neurovascular response functions in rat brain reveals residual differences that correlate with the differences in regional evoked potentials  

PubMed Central

The response of the rat visual system to flashes of blue light has been studied by blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI). The BOLD temporal response is dependent on the number of flashes presented and demonstrates a refractory period that depends on flash frequency. Activated brain regions included the primary and secondary visual cortex, superior colliculus (SC), dorsal Lateral Geniculate (DLG), and Lateral Posterior Nucleus (LP), which were found to exhibit differing temporal responses. To explain these differences, the BOLD neurovascular response function was modeled. A second order differential equation was developed and solved numerically to arrive at region-specific response functions. Included in the model are the light input from the diode (duty cycle), a refractory period, a transient response following onset and cessation of stimulus, and a slow adjustment to changes in the average level of the signal. Constants in the differential equation were evaluated for each region by fitting the model to the experimental BOLD response from a single flash, and the equation was then solved for multiple flashes. The simulation mimics the major features of the data; however, remaining differences in the frequency dependence of the response between the cortical and subcortical regions were unexplained. We hypothesized that these discrepancies were due to regional-specific differences in neuronal response to flash frequency. To test this hypothesis, cortical visual evoked potentials (VEPs) were recorded using the same stimulation protocol as the fMRI. Cortical VEPs were more suppressed than subcortical VEPs as flash frequency increased, supporting our hypothesis. This is the first report that regional differences in neuronal activation to the same stimulus lead to differential BOLD activation. PMID:18406628

Pawela, Christopher P.; Hudetz, Anthony G.; Ward, B. Douglas; Schulte, Marie L.; Li, Rupeng; Kao, Dennis S.; Mauck, Matthew C.; Cho, Younghoon R.; Neitz, Jay; Hyde, James S.

2008-01-01

394

Investigation of Liquid Transport/Diffusion through a Nanopore Driven by a Constant Pressure/Chemical Potential Difference.  

NASA Astrophysics Data System (ADS)

Fluid transport/diffusion through a nanopore in a membrane was investigated by using a novel molecular dynamics approach proposed in this study. The advantages of this method, relative to dual-control-volume grand-canonical molecular dynamics (DCV-GCMD), are that it eliminates disruptions to the system dynamics that normally created by inserting or deleting particles from control volumes, and that it functions well for dense systems as the number of particles in the studied system remain fixed. Using this method, we examined liquid argon transport/diffusion through a nanopore by performing non-equilibrium molecular dynamics (NEMD) simulations under different back-pressures/chemical potentials. The MD code was validated firstly by comparison with published experimental data, and NEMD results of the present method show that constant pressure/chemical potential difference across the membrane was readily achieved. The soundness of classical Navier-Stokes (NS) solutions for these nanochannel flows was also checked by direct comparison between the NS predictions and results from the proposed NEMD method. The density distributions along the nanopore for both methods were found to be significantly different, but the velocity profile had a similar pattern, although some difference between them exists.

Huang, Cunkui; Nandakumar, Kumar; Choi, Phillip; Kostiuk, Larry

2006-03-01

395

Time-scale and extent at which large-scale circulation modes determine the wind and solar potential in the Iberian Peninsula  

NASA Astrophysics Data System (ADS)

The North Atlantic Oscillation (NAO), the East Atlantic (EA) and the Scandinavian (SCAND) modes are the three main large-scale circulation patterns driving the climate variability of the Iberian Peninsula. This study assesses their influence in terms of solar (photovoltaic) and wind power generation potential (SP and WP) and evaluates their skill as predictors. For that we use a hindcast regional climate simulation to retrieve the primary meteorological variables involved, surface solar radiation and wind speed. First we identify that the maximum influence of the various modes occurs on the interannual variations of the monthly mean SP and WP series, being generally more relevant in winter. Second we find that in this time-scale and season, SP (WP) varies up to 30% (40%) with respect to the mean climatology between years with opposite phases of the modes, although the strength and the spatial distribution of the signals differ from one month to another. Last, the skill of a multi-linear regression model (MLRM), built using the NAO, EA and SCAND indices, to reconstruct the original wintertime monthly series of SP and WP was investigated. The reconstructed series (when the MLRM is calibrated for each month individually) correlate with the original ones up to 0.8 at the interannual time-scale. Besides, when the modeled series for each individual month are merged to construct an October-to-March monthly series, and after removing the annual cycle in order to account for monthly anomalies, these correlate 0.65 (0.55) with the original SP (WP) series in average. These values remain fairly stable when the calibration and reconstruction periods differ, thus supporting up to a point the predictive potential of the method at the time-scale assessed here.

Jerez, Sonia; Trigo, Ricardo M.

2013-12-01

396

Evaluation of the Potential Environmental Impacts from Large-Scale Use and Production of Hydrogen in Energy and Transportation Applications  

SciTech Connect

The purpose of this project is to systematically identify and examine possible near and long-term ecological and environmental effects from the production of hydrogen from various energy sources based on the DOE hydrogen production strategy and the use of that hydrogen in transportation applications. This project uses state-of-the-art numerical modeling tools of the environment and energy system emissions in combination with relevant new and prior measurements and other analyses to assess the understanding of the potential ecological and environmental impacts from hydrogen market penetration. H2 technology options and market penetration scenarios will be evaluated using energy-technology-economics models as well as atmospheric trace gas projections based on the IPCC SRES scenarios including the decline in halocarbons due to the Montreal Protocol. Specifically we investigate the impact of hydrogen releases on the oxidative capacity of the atmosphere, the long-term stability of the ozone layer due to changes in hydrogen emissions, the impact of hydrogen emissions and resulting concentrations on climate, the impact on microbial ecosystems involved in hydrogen uptake, and criteria pollutants emitted from distributed and centralized hydrogen production pathways and their impacts on human health, air quality, ecosystems, and structures under different penetration scenarios

Wuebbles, D.J.; Dubey, M.K., Edmonds, J.; Layzell, D.; Olsen, S.; Rahn, T.; Rocket, A.; Wang, D.; Jia, W.

2010-06-01

397

The BOLD response and the gamma oscillations respond differently than evoked potentials: an interleaved EEG-fMRI study  

PubMed Central

Background The integration of EEG and fMRI is attractive because of their complementary precision regarding time and space. But the relationship between the indirect hemodynamic fMRI signal and the more direct EEG signal is uncertain. Event-related EEG responses can be analyzed in two different ways, reflecting two different kinds of brain activity: evoked, i.e. phase-locked to the stimulus, such as evoked potentials, or induced, i.e. non phase-locked to the stimulus such as event-related oscillations. In order to determine which kind of EEG activity was more closely related with fMRI, EEG and fMRI signals were acquired together, while subjects were presented with two kinds of rare events intermingled with frequent distractors. Target events had to be signaled by pressing a button and Novel events had to be ignored. Results Both Targets and Novels triggered a P300, of larger amplitude in the Novel condition. On the opposite, the fMRI BOLD response was stronger in the Target condition. EEG event-related oscillations in the gamma band (32–38 Hz) reacted in a way similar to the BOLD response. Conclusions The reasons for such opposite differential reactivity between oscillations / fMRI on the one hand, and evoked potentials on the other, are discussed in the paper. Those results provide further arguments for a closer relationship between fast oscillations and the BOLD signal, than between evoked potentials and the BOLD signal. PMID:14499000

Foucher, Jack R; Otzenberger, Hélène; Gounot, Daniel

2003-01-01

398

Plant growth promotion potential is equally represented in diverse grapevine root-associated bacterial communities from different biopedoclimatic environments.  

PubMed

Plant-associated bacteria provide important services to host plants. Environmental factors such as cultivar type and pedoclimatic conditions contribute to shape their diversity. However, whether these environmental factors may influence the plant growth promoting (PGP) potential of the root-associated bacteria is not widely understood. To address this issue, the diversity and PGP potential of the bacterial assemblage associated with the grapevine root system of different cultivars in three Mediterranean environments along a macrotransect identifying an aridity gradient were assessed by culture-dependent and independent approaches. According to 16S rRNA gene PCR-DGGE, the structure of endosphere and rhizosphere bacterial communities was highly diverse (P = 0.03) and was associated with a cultivar/latitudinal/climatic effect. Despite being diverse, the bacterial communities associated with Egyptian grapevines shared a higher similarity with the Tunisian grapevines than those cultivated in North Italy. A similar distribution, according to the cultivar/latitude/aridity gradients, was observed for the cultivable bacteria. Many isolates (23%) presented in vitro multiple stress resistance capabilities and PGP activities, the most frequent being auxin synthesis (82%), insoluble phosphate solubilisation (61%), and ammonia production (70%). The comparable numbers and types of potential PGP traits among the three different environmental settings indicate a strong functional homeostasis of beneficial bacteria associated with grape root. PMID:23878810

Marasco, Ramona; Rolli, Eleonora; Fusi, Marco; Cherif, Ameur; Abou-Hadid, Ayman; El-Bahairy, Usama; Borin, Sara; Sorlini, Claudia; Daffonchio, Daniele

2013-01-01

399